CSF-1

CSF-1 E. Richard Stanley* Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA * corresponding author tel: 718-430-2344, fax: 718-430-8567, e-mail: [email protected] DOI: 10.1006/rwcy.2000.09005.

SUMMARY Colony-stimulating factor 1 (CSF-1) is the primary regulator of the survival, proliferation, and differentiation of mononuclear phagocytes and also regulates cells of the female reproductive tract. Produced by a wide variety of cell types, CSF-1 acts humorally and locally. It is secreted into the circulation as a glycoprotein or chondroitin sulfate-containing proteoglycan and expressed on the surface of CSF-1producing cells. CSF-1 effects are mediated by the CSF-1 receptor tyrosine kinase that is encoded by the c-fms protooncogene product. Osteopetrotic Csf1op/ Csf1op mice possess an inactivating mutation in the CSF-1 gene and besides striking reductions in numbers of osteoclasts and certain tissue macrophages, they exhibit a pleiotropic phenotype. This pleiotropic phenotype may be due to trophic and/or scavenger actions of macrophages and other cell types regulated by CSF-1, that control such characteristics as dermal thickness, male and female fertility, and neural processing. CSF-1 appears to play an autocrine and/ or paracrine role in cancers of the female reproductive tract and the myeloid system.

BACKGROUND

Discovery Colony-stimulating factors (CSFs) were so named because of their ability to stimulate the formation of colonies of mature myeloid cells from single immature hematopoietic precursor cells plated in semisolid medium. The homodimeric glycoprotein colonystimulating factor 1 (CSF-1) was the first of these factors to be purified (Stanley and Heard, 1977) and

was shown to stimulate the formation of colonies of macrophages (Stanley et al., 1978). Specific antibody neutralization studies and the development of specific radioimmunoassays and radioreceptor assays (Stanley, 1979; Das et al., 1980, 1981), indicated that it was distinct from the other CSFs (Stanley, 1985).

Alternative names Prior to the delineation of the CSF subclasses, CSF-1 was referred to as CSF, macrophage and granulocyte inducer IM (MGI-IM) or alternatively, macrophage growth factor (MGF), which was assayed by its ability to stimulate the proliferation of activated peritoneal macrophages (Stanley, 1994). Currently, it is also known as macrophage colony stimulating factor (M-CSF), although its action is not restricted to macrophages. Proteoglycan-100 has been shown to be the proteoglycan form of CSF-1 (Partenheimer et al., 1995).

Structure Through alternative mRNA splicing and differential posttranslational proteolytic processing, mouse and human CSF-1 can either be secreted into the circulation as an 80±100 kDa glycoprotein or 130± 160 kDa chondroitin sulfate-containing proteoglycan, or expressed as a membrane-spanning 68±86 kDa glycoprotein on the surface of CSF-1-producing cells. All biologically active forms are dimeric and contain the N-terminal 150 amino acids of the fulllength  520 amino acid CSF-1 precursor that are required for in vitro biological activity (Stanley, 1994) (Figure 1).

Figure 1 CSF-1 genomic organization, expression, and structure. The CSF-1 gene is localized to human chromosome 1p13-p21 and mouse chromosome 3. The bottom half of the diagram shows the intron±exon structure and four representative human cDNA clones that have been sequenced. Similar mouse clones have been isolated. Exons (1±10) and the transmembrane domain (TM, cross-hatched), are indicated. The 4 kb and 2.1 kb mRNAs arise from alternative usage of untranslated regions encoded by exons 9 and 10, the latter exon encoding putative mRNA instability sequences (AU). The 1.6 kb and 3.1 kb mRNAs are products of a splicing reaction that results in the use of a short form of exon 6. The approximate intracellular proteolytic cleavage sites (arrowheads) and the chondroitin sulfate glycosaminoglycan addition site (GAG) are also shown. The top half of the diagram shows the processing of CSF-1 homodimers encoded by both the short and long coding regions. Hatched regions represent those present in the mature secreted or released glycoprotein forms while both hatched and filled regions are present in the major secreted proteoglycan form. N-Linked (filled arrowheads) and O-linked (open circles) glycosylation sites, the chondroitin sulfate chain (linked, open hexagons) and the transmembrane domain (filled region) are shown. Reproduced from Stanley (1998).

CSF-1

Main activities and pathophysiological roles CSF-1 is the primary regulator of the survival, proliferation, and differentiation of mononuclear phagocytes, including tissue macrophages and osteoclasts. It has also been shown to stimulate CD5‡ B lymphocytes to develop into biphenotypic B/macrophage cells (Borrello and Phipps, 1999). CSF-1 acts locally and humorally, preferentially regulating the development of macrophages found in tissues undergoing active morphogenesis and/or tissue remodeling. Cells requiring CSF-1 for their development may regulate, via trophic and/or scavenger functions, bone resorption, male fertility, the thickness of the dermis, and neural processing. In the female reproductive system, CSF-1 regulates the development of macrophages and the function of nonmononuclear phagocytic, CSF-1 receptor-expressing cells. Mice bearing the mutation osteopetrotic (Csf1op) possess an inactivating mutation in the CSF-1 gene and exhibit a pleiotropic phenotype that reflects the roles of the cells regulated by CSF-1. CSF-1 appears to play an autocrine and/or paracrine role in cancers of the ovary, endometrium, breast, and myeloid tissues (Janowska-Wieczorek et al., 1991; Kacinski, 1995; Pollard and Stanley, 1996; Scholl et al., 1996; HaranGhera et al., 1997; Sapi and Kacinski, 1999).

GENE AND GENE REGULATION

Accession numbers CSF-1 cDNAs have been cloned from several species and are listed below with their GenBank accession numbers. Human: CSF-1522: M37435 (Wong et al., 1987); X05825 (Ladner et al., 1987); NM_000757 (Takahashi et al., 1989) CSF-1406: U22385 (Cerretti et al., 1988) CSF-1224: M21149 (Kawasaki et al., 1985; Pampfer et al., 1991) Mouse: CSF-1520 exon 9 30 UTR: M21149 (Ladner et al., 1988); X05010 (DeLamarter et al., 1987) CSF-1520 exon 10 30 UTR: M21952 (Ladner et al., 1988) CSF-1520: M15692 (Rajavashisth et al., 1987) Rat: CSF-1520: M84361 (Borycki et al., 1993) Rabbit: CSF-1: E14817

913

Bovine: CSF-1522: D87917 (Yoshihara et al., 1998) CSF-1225: D87918 (Yoshihara et al., 1998)

Chromosome location The human CSF-1 gene is approximately 21 kb in length, comprising 10 exons (Ladner et al., 1987; Kawasaki and Ladner, 1990) (Figure 1). It is localized to human chromosome 1p13-p21. The mouse CSF-1 gene (Csf1) is localized to chromosome 3F3 at what was formerly known as the op locus (Stanley, 1994). Exon 1 encodes the 50 UTR and a portion of the signal sequence, exons 2±6 encode the CSF-1 precursor domain expressed on the luminal side of the endoplasmic reticulum, the entire transmembrane domain and a portion of the cytoplasmic domain, exon 6 spanning the transmembrane domain and portions of the other two domains. Exons 7 and 8 encode the remainder of the cytoplasmic domain, exon 8 also encoding a small portion of the 30 UTR, which is predominantly encoded by exons 9 or 10 (Figure 1). The most abundant mRNA transcripts are those resulting from the alternative use of different 30 UTRs encoded by exons 9 (0.68 kb) and 10 (2 kb) (Ladner et al., 1987; Wong et al., 1987). The 30 UTR encoded by exon 10 contains AU-rich sequences, which may confer mRNA instability. Alternative mRNA splicing in exon 6 can result in shortened coding regions in CSF-1 mRNAs that affect the processing of the CSF1 protein precursors they encode (Kawasaki et al., 1985; Ladner et al., 1987; Wong et al., 1987; Cerretti et al., 1988). The abundance of these messages, which encode the relatively stably expressed cell surface form of CSF-1, is less. Additional species of CSF-1 mRNA have been described in specific cell lines.

Regulatory sites and corresponding transcription factors The 50 promoter regions of the human (Ladner et al., 1987) and mouse (Harrington et al., 1991) CSF-1 genes have been cloned. They exhibit 80% sequence similarity in the region 450 bp upstream of the transcription start site. Several elements, involved in the regulation of CSF-1 gene expression, are located within this region and the control of gene expression in monocytes and fibroblasts is mediated by common and cell type-specific trans-acting factors (Konicek et al., 1998).

914 E. Richard Stanley

Cells and tissues that express the gene See Cellular sources and tissue expression.

PROTEIN

Ladner, 1990). The cysteine residues involved in intrachain (Cys7±Cys90, Cys48±Cys139, Cys102± Cys146) and interchain, (Cys31±Cys31, Cys157± Cys157, Cys159±Cys159) disulfide bonding in human CSF-1 (Glocker et al., 1993; Wilkins et al., 1993) are highly conserved in published CSF-1 sequences from all species.

Accession numbers

Description of protein

Human: CSF-1522: AAA52117 (Wong et al., 1987); FQHUMP (Kawasaki et al., 1985; Ladner et al., 1987; Wong et al., 1987); AAA59573 (Takahashi et al., 1989) CSF-1406: AAA59572 (Cerretti et al., 1988) CSF-1224: AAA52120 (Kawasaki et al., 1985; Pampfer et al., 1991) Mouse: CSF-1520: P07141 (Ladner et al., 1988); A31401 (Ben Avram et al., 1985); CAA28660 (DeLamarter et al., 1987) Rat: CSF-1520: AAA03032 (Borycki et al., 1993) Bovine: CSF-1522: BAA31556 (Yoshihara et al., 1998) CSF-1225: BAA31557 (Yoshihara et al., 1998)

The secreted forms of mouse CSF-1 are homodimeric glycoprotein and proteoglycan molecules (Price et al., 1992). Reinterpretation of earlier data on the biosynthesis and secretion of human CSF-1 (Price et al., 1992; Stanley, 1994) together with other studies (Suzu et al., 1992), indicate that the secreted forms of human CSF-1, previously thought to be exclusively glycoprotein, are predominantly proteoglycan. As shown in Figure 1, the membrane-spanning CSF-1 precursor encoded by the full-length mRNA is cotranslationally N-glycosylated in the endoplasmic reticulum. It rapidly undergoes a dimerization that involves the formation of interchain disulfide bonds (Price et al., 1992) and the resulting homodimeric precursor moves to the Golgi, where the N-linked oligosaccharides are converted from high mannose to complex type and O-linked oligosaccharides are added. Among these O-linked oligosaccharides is an 18,000 kDa chondroitin sulfate chain that is added to Ser277 (human) or Ser276 (mouse) within the consensus sequence for glycosaminoglycan addition (Price et al., 1992; Suzu et al., 1992). Once in the secretory vesicle, the secreted forms of the mature CSF-1 are cleaved from the precursor. Depending on whether the proteolytic cleavage takes place on the amino terminal side or the carboxyl terminal side of the glycosaminoglycan addition site, they are secreted as either the 80±100 kDa glycoprotein or 130±160 kDa proteoglycan. Both forms rapidly accumulate in the extracellular medium with a half-time of 40 minutes (Price et al., 1992) and have similar receptor binding and in vitro biological activities (Price et al., 1992; Suzu et al., 1997). Three sequenced human CSF-1 cDNAs possess shorter than full-length coding regions due to alternative splicing in exon 6 (Kawasaki et al., 1985; Cerretti et al., 1988; Pampfer et al., 1991). These clones encode precursors of 224 (CSF-1224) (Kawasaki et al., 1985; Pampfer et al., 1991) or 406 (CSF-1406) (Cerretti et al., 1988) amino acids in which the amino acids 150±447 and 332±447 respectively, have been spliced out (Figure 1 and Figure 2). CSF1224, also found in the mouse (Pollard and Stanley, 1996), encodes a precursor in which the region

Sequence cDNAs encoding CSF-1 have been isolated from several species and sequenced. A comparison of the amino acid sequences for human and mouse CSF-1 is shown in Figure 2. The coding region of the fulllength human CSF-1 precursor comprises a 32 amino acid signal sequence, followed by 522 additional residues which contain four potential N-linked glycosylation sites, a single consensus sequence for glycosaminoglycan addition (acidic residues -SerGly-X-Gly/Ala) at Ser277 and a hydrophobic stretch of 23 amino acids at residues 464±486 that encodes the transmembrane domain and is followed by a sequence of charged amino acids (Arg-Trp-Arg-ArgArg) that apparently functions as a `stop transfer' sequence (Kawasaki et al., 1985; Ladner et al., 1987; Wong et al., 1987). Without its 32 amino acid signal sequence, the full-length coding region of the mouse transcript predicts a precursor of 520 amino acids with 59.6% sequence similarity to human CSF-1 and all of the features of human CSF-1 mentioned above (Ladner et al., 1988). The highest degree of sequence similarity (80.5%) occurs for the amino terminal residues 1±149, which have been shown to be required for in vitro biological activity (Kawasaki and

CSF-1

915

Figure 2 Amino acid sequences of the human CSF-1522 and mouse CSF-1520 precursors. In mouse CSF-1520, amino acid identity with the human sequence is indicated by an asterisk. Maximal alignment of sequences was achieved by introducing four gaps, each indicated by a dash. Signal peptide and transmembrane domains are indicated respectively by large open and filled boxes, N-linked glycosylation sites by the heavy-lined open boxes and cysteines involved in the disulfide bonds by light-lined open boxes. The consensus sequence for glycosaminoglycan addition (heavy underline) and the four  helical and two pleated regions (overlined) are also shown. Amino acids 150± 447 (between arrows numbered 1) and 332±447 (between arrows numbered 2) are deleted in truncated forms that are derived from alternatively spliced mRNAs.

encoding the proteolytic cleavage sites, the sites for Olinked oligosaccharide addition (including the glycosaminoglycan site), and half of the potential N-linked glycosylation sites have been deleted. It differs significantly from the full-length precursor CSF1522 in its processing and expression. Like CSF-1522,

it is cotranslationally glycosylated in the endoplasmic reticulum, rapidly dimerizes there and then moves to the Golgi, where its N-linked oligosaccharides are converted to complex type. However, it is not proteolytically cleaved in the secretory vesicle. Instead, upon fusion of the vesicle with the plasma membrane,

916 E. Richard Stanley it is expressed as a membrane-spanning protein on the cell surface (Rettenmier et al., 1987) (Figure 1). In contrast to the cells expressing CSF-1522, which secrete soluble CSF-1, fixed cell layers expressing CSF-1224 stimulate the proliferation of overlayered macrophages, indicating that the membrane-spanning, cell surface form is biologically active (Stein et al., 1990). Studies in mouse L cells indicate that this form of CSF-1 is stably expressed at the cell surface (t1/2 ˆ 7 hours) (Price et al., 1992). However, release of CSF-1 by proteolysis from CSF-1224 at the cell surface is greatly stimulated by activation of protein kinase C (Stein and Rettenmier, 1991). Multiple factors determine the selection of the ectodomain cleavage site for the release of bioactive CSF-1 from CSF224 (Deng et al., 1998). It is not clear how the processing of CSF-1406 occurs. It is possible that it is both expressed on the cell surface and secreted. Expression of transcripts encoding the cell surface and secreted forms of CSF-1 can be differentially regulated by sex steroid hormones (Lea et al., 1999).

Discussion of crystal structure The first 149 amino acids are conserved in all biologically active forms of CSF-1 and are required for in vitro biological activity (Stanley, 1994). The crystal structure of this region (amino acids 4±158) has been determined at 2.5 AÊ (Pandit et al., 1992) and despite its lack of sequence similarity with members of the cytokine family, it also possesses a similar four  helical bundle/anti-parallel ribbon structure. The monomer is an antiparallel four  helical bundle in which the helices run up-up-down-down, similar to the connectivity observed in GM-CSF and growth hormone. However, the relative lengths of the helices and the connecting loops differ and there are differences in the disulfide bonds in all three proteins (Pandit et al., 1992). The exon±intron junctions occur at nearly the same positions in the three-dimensional structure of all three, at the end of helix A, at the beginning of helix B, at the end of helix C, and the end of helix D. The dimer is formed by linking two CSF-1 monomers end-to-end, yielding a very flat, elongated structure with dimensions of approximately 80  30  20 AÊ (Pandit et al., 1992). There are three intrachain disulfide bonds per monomer and an interchain disulfide bond that maintain the dimeric state (Glocker et al., 1993; Wilkins et al., 1993). The interchain disulfide bond of the truncated biologically active form is not necessary for activity, provided that the intrachain disulfide bonds remain intact (Krautwald and Baccarini, 1993).

Important homologies The membrane-spanning, cell surface form of CSF-1 (CSF-1224), stem cell factor, and Flt-3 ligand all have short intracellular domains and share significant sequence similarity in the extracellular domain (Bazan, 1991). The human CSF-1 Cys7±Cys90 and Cys48± Cys139 intrachain disulfide bonds are conserved in all three, while CSF-1 possesses an extra intrachain disulfide bond and an additional Cys involved in the interchain disufide that links the monomers.

Posttranslational modifications All forms of CSF-1 are highly glycosylated with Nand O-linked oligosaccharides. The secreted forms are more glycosylated than the cell surface form. The most glycosylated form is the secreted proteoglycan which may possess one or two  18,000 molecular weight chondroitin sulfate chains per dimer (Price et al., 1992; Suzu et al., 1992). Two different types of glycosaminoglycan that differ in their ability to bind low density lipoproteins have been identified in the proteoglycan CSF-1 (Chang et al., 1998).

CELLULAR SOURCES AND TISSUE EXPRESSION

Cellular sources that produce CSF-1 is found and synthesized in most tissues, including submaxillary gland, lung, spleen, kidney, lymph nodes, brain, liver, testis, and ovary (Bartocci et al., 1986; Roth et al., 1997). A variety of different types of normal cells synthesize CSF-1, including fibroblasts, endothelial cells, bone marrow stromal cells, osteoblasts, thymic epithelial cells, keratinocytes, astrocytes, myoblasts, mesothelial cells, liver parenchymal cells (Stanley, 1994), thyrocytes (Matsumura et al., 1999), and adipocytes (Levine et al., 1998). CSF-1 is synthesized by ovarian granulosa cells, oviduct epithelium and in large amounts by uterine epithelial cells during pregnancy (Bartocci et al., 1986; Pollard et al., 1987; Pollard and Stanley, 1996; Cohen et al., 1999). Cells from many neoplastic cell lines, including leukemic, lymphoma, and pancreatic cell lines, and from adenocarcinomas of the lung, breast, ovary, and endometrium synthesize CSF-1. In several cases proliferation of these neoplastic cells is under CSF-1 autocrine control (Roth and Stanley, 1992; Stanley, 1994).

CSF-1

917

Eliciting and inhibitory stimuli, including exogenous and endogenous modulators

IN VITRO ACTIVITIES

In vitro CSF-1 synthesis is stimulated following the activation of monocytes, endothelial cells, T lymphocytes, B lymphocytes, fibroblasts, and mesangial cells (Roth and Stanley, 1992). Stimulatory cytokines for human monocytes, mouse macrophages, and several other cell types reportedly include bacterial lipopolysaccharide (LPS), IgG complexes, IL-1, IFN , TNF, IL-4, IL-6, and GM-CSF. However, caution must be used in interpreting some of these reports as indicated by Hamilton (1993). Various stimuli have also been reported to increase CSF-1 synthesis and secretion by retinal pigment epithelial cells, chondrocytes, thymic epithelial cells, osteoblasts, endometrial stromal cells, keratinocytes, and thyroid follicular cells. In several cell types other agents regulate CSF-1 expression as well. For example, in osteoblasts, synthesis is increased by IL-4 (Lacey et al., 1994), TNF (Kaplan et al., 1996), PTH, PTHrP (Weir et al., 1993), 1,25-dihydroxyvitamin D3 (Rubin et al., 1996), histamine (Takamatsu and Nakano, 1998), and dexamethasone (Rubin et al., 1998) and inhibited by estrogen (Srivastava et al., 1998). Endometrial stromal cell synthesis is stimulated by progesterone, testosterone (Kanzaki et al., 1995), IFN , and platelet-activating factor (Nasu et al., 1999), while endothelial and mesangial cell synthesis is stimulated by oxidized LDL (Pai et al., 1995; Rajavashisth et al., 1995) and inhibited by NO (Peng et al., 1995). Human thyroid follicular cell synthesis is stimulated by IL-6 and inhibited by TGF (Matsumura et al., 1999). LPS, either directly, or indirectly through TNF or IL-1, potently stimulates mouse CSF-1 synthesis by many tissues in vivo, resulting in an increase of up to 7-fold in the circulating CSF-1 concentration approximately 4 hours after administration (Roth et al., 1997). Modified LDL increased serum CSF activity 7- to 26-fold following injection in mice (Liao et al., 1991) and increased CSF-1 synthesis by endothelial cells and smooth muscle cells in vitro (Rajavashisth et al., 1990; Clinton et al., 1992).

CSF-1 was initially defined as a macrophage colonystimulating factor or macrophage growth factor. While its action is now clearly not limited to mononuclear phagocytes (hematopoietic macrophage colony-forming cell ! monoblast ! promonocyte ! monocyte ! macrophage) these cells, including osteoclast precursors, are stimulated to survive, proliferate, and differentiate in response to CSF-1. Apart from their production via the mononuclear phagocytic lineage, CSF-1 can also stimulate macrophage development from CD5‡ B lymphocytes (Borrello and Phipps, 1999). In addition, antisense experiments indicate that there is autocrine regulation by CSF-1 during the early proliferative step following induction of myogenic differentiation in L6 1 rat myoblasts (Borycki et al., 1995a, 1995b, 1995c). Other cells, including trophoblastic and decidual cells are apparently regulated by CSF-1, but CSF-1 does not appear to regulate their proliferation. Circulating monocytes are noncycling cells in vivo. However, in the mouse, monocytes and their precursors, hematopoietic macrophage colony-forming cells, monoblasts, and promonocytes, are all capable of forming macrophage colonies in the presence of CSF-1 with very high plating efficiency. Macrophages that are recently derived from monocytes possess a slightly reduced plating efficiency, while resident tissue macrophage populations have relatively poor plating efficiencies, containing many macrophages that are incapable of proliferating in response to CSF-1 (Stanley et al., 1978, 1983). Human mononuclear phagocytes, in contrast to mouse mononuclear phagocytes, generally exhibit a poorer proliferative response to CSF-1 (Das et al., 1981) and the proliferative response of monocytes and macrophages is virtually nonexistent (Bennett et al., 1992). In vitro experiments with very primitive hematopoietic cells from the bone marrow of mice recovering from treatment with 5-fluorouracil resulted in the purification and description of hematopoietin 1, a cytokine that synergized with CSF-1 and other hematopoietic growth factors in stimulating the proliferation and differentiation of these cells along multiple hematopoietic lineages (Bartelmez and Stanley, 1985; Jubinsky, 1985; Stanley et al., 1986). Hematopoietin 1 was subsequently shown to be IL-1 (Mochizuki et al., 1986). Very primitive hematopoietic precursor cells cannot proliferate in

RECEPTOR UTILIZATION The CSF-1 receptor (CSF-1R), encoded by the c-fms protooncogene (Sherr et al., 1985), is a member of the type III receptor tyrosine kinase family that includes the PDGF, SCF, and Flk-2/Flt-3 receptors.

In vitro findings

918 E. Richard Stanley response to CSF-1 alone, but the combination of CSF-1 with other hematopoietic cytokines, such as IL-1, IL-3, and SCF, dramatically increases both their plating efficiency and colony size (Bartelmez et al., 1989; Williams et al., 1992). Recently, combined treatment of mice with IL-1 and CSF-1 has been shown to be particularly effective in accelerating recovery from drug-induced myelosuppression in mice (Kovacs et al., 1998). Several systems have been used to demonstrate that CSF-1 is required for the generation of osteoclasts from precursor cells in vitro (Felix et al., 1994; Pollard and Stanley, 1996). Astrocytes from brain have been shown to produce CSF-1 and cultured microglia to express the CSF-1R and proliferate in response to CSF-1. In addition, CSF1 in serum-free primary embryonic brain cultures derived from the hippocampus, cerebellum, cortex or hypothalamus stimulated increased cell numbers and process outgrowth of the vast majority of neurons in all brain regions, with networks of processes extending between almost all cells in the cortical cultures. These neurotropic effects of CSF-1 are likely to be mediated via its action on microglia (Michaelson et al., 1996; Pollard and Stanley, 1996). Although CSF-1 has been claimed to stimulate macrophages and monocytes to produce prostaglandin E, plasminogen activator, IL-1, IFN , and oxygen metabolites, many of these findings have been questioned. CSF-1 appears to play an important role in priming macrophages to respond to other stimuli, such as LPS, by releasing cytokines such as TNF, IL-1, and IL-6 (Hamilton, 1993). CSF-1 has minor effects in promoting phagocytosis, tumor cytotoxicity, and resistance to viral infections (Ralph et al., 1986; Hamilton, 1993). It stimulates the synthesis and surface expression of macrophage scavenger receptor (De Villiers et al., 1994) and maintains the expression of CD36, an oxidized LDL lipoprotein scavenger receptor (Huh et al., 1996). CSF-1 stimulation of macrophages causes rapid morphological changes, including cell spreading, extension of lamellopodia, and formation of ruffles on the cell surface (Boocock et al., 1989), followed by cell polarization and increased motility (Webb et al., 1996; Allen et al., 1998). It has been shown to stimulate invasiveness of CSF-1Rexpressing macrophage and carcinoma cell lines in a human amniotic basement membrane invasion assay (Filderman et al., 1992). CSF-1 enhances phagocytosis, but not bactericidal activity of the intracellular bacterium Listeria monocytogenes (Cheers et al., 1989).

Regulatory molecules: Inhibitors and enhancers IL-1, IL-3, SCF (Bartelmez et al., 1989; Williams et al., 1992), GM-CSF (McNiece et al., 1988), IL-6 (Bot et al., 1989), IL-2 (Li et al., 1989), IL-7 (Jacobsen et al., 1994), and TNF (Guilbert et al., 1993) synergize with CSF-1 to regulate the proliferation and differentiation of primitive hematopoietic cells to macrophages. CSF-1 also synergizes with osteoprotegerin ligand (OPGL)/osteoclast differentiation factor (ODF)/TNF-related activation-induced cytokine (TRANCE) to stimulate osteoclastogenesis from hematopoietic cells (Lacey et al., 1998; Yasuda et al., 1998). CSF-1-induced macrophage colony formation or macrophage proliferation has been shown to be inhibited by prostaglandin E (Williams, 1979), IFN , TNF, LPS (Vairo et al., 1991), glucocorticoids (Hamilton, 1983), and opioids (Roy et al., 1996).

Bioassays used The colony-stimulating factor bioassay is based on the CSF-dependent stimulation of bone marrow cells to form colonies of granulocytes and/or macrophages in semisolid culture media. A limitation of this assay is that it cannot be used to specifically assay CSF-1 in preparations that contain other CSFs. However, CSF-1-specific competitive binding assays have been developed that are based on the ability of CSF-1 in assay samples to complete for the binding of labeled CSF-1 with either anti-CSF-1 antibody or the CSF-1 receptor on intact cells (Stanley, 1979; Das et al., 1980, 1981; Stanley, 1981). These assays are relatively species-specific, but all have the advantage of only detecting biologically active CSF-1. Several nonradioactive competitive immunoassays with similar properties have recently been developed. Table 1 summarizes the sensitivity and specificity of assays for CSF-1.

IN VIVO BIOLOGICAL ACTIVITIES OF LIGANDS IN ANIMAL MODELS

Normal physiological roles Administration of CSF-1 increases blood monocyte and tissue macrophage numbers (Hume et al., 1988; Munn et al., 1990), although some populations, e.g. alveolar and peritoneal macrophages, are not

CSF-1

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Table 1 CSF-1 assay methods a

CSF specificity

CSF-1 dose-response range (ng)

Assay time (days)

Bone marrow colony formation

None

0.1±1.5

7±14

Peritoneal exudate macrophage colony formation

CSF-1, GM-CSF

0.4±6.0

14±28

3

HTdR uptake by peritoneal exudate macrophages

CSF-1, GM-CSF

0.4±6.0

7

3

HTdR uptake by bone marrow cells

All

0.2±3.0

4

Mouse

Mouse CSF-1

0.025±1.2

1±2

Human

Human CSF-1

0.025±1.2

1±2

Mouse CSF-1 and human CSF-1

0.025±1.2

1

0.040±1.2

1

Assay method

Radioimmunoassay

Radioreceptor assay (mouse)

a

Stanley (1981).

increased (Asakura et al., 1997). In contrast, the absence of CSF-1 in the Csf1op/Csf1op mouse is associated with a large decrease in the concentration of mononuclear phagocytes in blood, bone marrow, and major macrophage-containing tissues (Marks and Lane, 1976; Wiktor-Jedrzejczak et al., 1982, 1991; Naito et al., 1991; Cecchini et al., 1994). These observations clearly indicate that CSF-1 is the primary regulator of mononuclear phagocyte production. In addition, other studies have demonstrated that while circulating CSF-1 regulates the development and maintenance of certain tissue macrophage populations, e.g. Kupffer cells, other populations are regulated by locally produced CSF-1 (WiktorJedrzejczak et al., 1991; Cecchini et al., 1994; Roth et al., 1998). The osteopetrotic phenotype of the CSF-1-null Csf1op/Csf1op mouse clearly demonstrates the essential osteoclastogenic role of CSF-1. Wild-type splenic hematopoietic precursor cells proliferate and differentiate to tartrate-resistant acid phosphatase-positive osteoclasts when co-cultured with stromal osteoblasts from wild-type mice, or Csf1op/Csf1op osteoblasts and CSF-1, but not with Csf1op/Csf1op osteoblasts alone, demonstrating that osteoblast-derived CSF-1 is required for osteoclast formation (Felix et al., 1994; Pollard and Stanley, 1996). In cultured embryonic mouse metatarsals, CSF-1 mRNA is locally and temporally expressed during the period of osteoclast development, and osteoclasts as well as their precursors express the CSF-1R (Felix et al., 1994; Pollard and Stanley, 1996)). Consistent with an action of CSF-1 on proliferating osteoclast precursor cells, culture of Csf1op/Csf1op mouse metatarsals with CSF-1

induces osteoclastogenesis (Morohashi et al., 1994). CSF-1 supports osteoclast differentiation in cooperation with OPGL/ODF/TRANCE and the combination of both factors overcomes the requirement for osteoblastic cells in co-cultures with hematopoietic cells. CSF-1 alone causes the development of small mononuclear cells, whereas OPGL stimulates the development of active osteoclasts in a CSF-1-dependent fashion. This synergy may in part be explained by CSF-1-induced OPGL receptor expression on osteoclast precursors (Lacey et al., 1998; Yasuda et al., 1998). Of particular interest is the difference between the CSF-1 requirement for osteoclast differentiation and for maintenance of tissue macrophage populations. For example, a single injection of CSF-1 in a Csfmop/Csfmop mouse is sufficient to differentiate osteoclast Csf1op/Csf1op progenitors and correct the osteopetrotic condition (Kodama et al., 1993), whereas repeated injections are required to maintain tissue macrophage populations after their development (Cecchini et al., 1994; Pollard and Stanley, 1996). Apart from its role in the proliferation and differentiation of osteoclast progenitors (Felix et al., 1994; Pollard and Stanley, 1996), CSF-1 also appears to play a role in regulating osteoclast function. CSF-1 stimulates increases in osteoclast survival, size, and multinucleation (Jimi et al., 1995; Lees and Heersche, 1999). It also stimulates the migration, chemotaxis, spreading, and survival of isolated osteoclasts, inhibiting their resorptive activity by reducing the proportion of bone resorbing cells (Felix et al., 1994; Pollard and Stanley, 1996). The bone resorptive and migratory states of the osteoclast may be mutually

920 E. Richard Stanley exclusive so that CSF-1 production by the osteoblast may be important in regulating the distribution of osteoclasts (Fuller et al., 1993). Here the cell surface and proteoglycan forms of CSF-1 could play important and different roles. The osteoblast cell surface form may be involved in direct cell±cell interaction with osteoclasts or be released locally by cell surface proteolysis. The proteoglycan form may be differentially localized to bone via its chondroitin sulfate chains after its secretion from osteoblasts or recruitment from the circulation (Felix et al., 1994; Pollard and Stanley, 1996). Studies of the postnatal development of tissue macrophage populations using Csf1op/Csf1op mice indicate that several tissue macrophage populations are partially or completely dependent on CSF-1 for their development and maintenance, while the development and maintenance of others are largely unaffected by its absence (Table 2). In many of the `CSF-1-dependent' tissues, the macrophage density is normally highest at birth and the requirement for CSF-1 therefore appears to be prenatal. In general, the `CSF-1-dependent' macrophages are in tissues which undergo significant perinatal remodeling and morphogenesis and are believed to play significant roles in these processes by producing trophic factors or acting as scavengers. In several of these tissues, the absence of the `CSF-1-dependent' macrophages is correlated with altered function of the tissue (Cecchini et al., 1994; Pollard and Stanley, 1996). CSF-1 is either synthesized locally, or the proteoglycan form specifically sequestered, in the regulation of macrophages of muscle, tendon, periosteum, synovium, bladder, salivary gland, gut, adrenals, and bone marrow (Cecchini et al., 1994). Irrespective of whether the tissue macrophage requirement is for circulating or locally produced CSF-1, the requirement is, in many cases, prenatal as well as postnatal (Table 2). In contrast to the `CSF-1-dependent' macrophages, the development of macrophages of the epidermis (Langerhans cells), thymus, and lymph node (with the exception of those of the subcapsular sinus) (WitmerPack et al., 1993) is largely unaltered in Csf1op/Csf1op mice (Takahashi et al., 1992., 1993; Witmer-Pack et al., 1993; Cecchini et al., 1994). The macrophages of this group are believed to be important for immunological and inflammatory responses and represent a small proportion of total body macrophages, most of which are found in the liver, gut, and brain. Since they express the CSF-1R, they are possibly regulated in some way by CSF-1 in the adult (Cecchini et al., 1994). CSF-1 does not seem to have a major immunological role. It does not have a significant role in in vivo phagocytic function, normal delayed-type

hypersensitivity, and normal T and B cell responses to ovalbumin or sheep red blood cells (WiktorJedrzejczak et al., 1992; Chang et al., 1995). In fact, many of the effects of CSF-1, including the enhancement of the killing of Candida albicans and Listeria monocytogenes (Roth and Stanley, 1992), as well as the impaired ability of Csf1op/Csf1op mice to release TNF and G-CSF into the circulation in response to bacterial endotoxin, and to form granulomatous lesions (Stanley, 1994; Pollard and Stanley, 1996), might be explained by the chemotactic role or macrophage growth-promoting activities of CSF-1. The dramatic elevation of uterine CSF-1 concentration during pregnancy (Bartocci et al., 1986; Pollard et al., 1991) and the detection of CSF-1R mRNA in the placenta (Pollard and Stanley, 1996) suggested non-mononuclear phagocytic actions of CSF-1 during pregnancy. Before implantation, CSF-1 mRNA and protein are detected in the oviduct (Arceci et al., 1992). CSF-1 mRNA is also elevated in the uterus at estrus during the estrous cycle (Sanford et al., 1992). During pregnancy, uterine epithelial CSF-1 synthesis, stimulated by progesterone and estradiol-17 , increases exponentially from day 3 of pregnancy so that uterine concentrations are increased  5-fold at implantation and  1000-fold at term. This increase is local, since circulating CSF-1 is only increased by  1.4-fold (Bartocci et al., 1986; Pollard et al., 1987; Arceci et al., 1989). The uterine CSF-1 mRNA is predominantly the 2.3 kb, exon 9containing species encoding the secreted forms of CSF-1, although mRNA encoding the cell surface form is also present, so that juxtacrine as well as paracrine interactions of CSF-1 may occur during pregnancy. There is reciprocity in the expression of the CSF-1R. Maternal CSF-1R mRNA is first found in developing follicles and persists in the growing oocyte to ovulation (Arceci et al., 1992). Zygotic mRNA appears at the late two-cell stage and remains (Arceci et al., 1992). After decidualization commences, the primary decidual cells surrounding the invading embryo express high levels of CSF-1R mRNA (Arceci et al., 1989, 1992; Regenstreif and Rossant, 1989) and there are low intra-embryonic levels. After placentation, there is strong expression in the various layers of the trophoblast and expression in decidual cells persists at low levels in the decidua basalis (Arceci et al., 1989; Regenstreif and Rossant, 1989). A similar pattern of CSF-1 and CSF-1R expression is found in the human reproductive tract, except that CSF-1 is also expressed by trophoblast and decidual cells (Pollard and Stanley, 1996). These temporal-spatial patterns of CSF-1/CSF-1R expression, together with the sex steroid hormone regulation of CSF-1 expression, strongly implicate CSF-1 in the

CSF-1

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Table 2 CSF-1 dependence of tissue macrophage development and effect of circulating CSF-1 on macrophage development in CSF-1-null Csflop/Csflop mice Tissue

Detection method

CSF-1 dependence

Effect of postnatal circulating CSF-1

Muscle

F4/80

Complete

Complete

Tendon

F4/80

Complete

None

Dermis

F4/80

Complete

None

Periosteum

F4/80

Complete

Partial/nonea

Synovium

F4/80

Complete

None

Kidney

F4/80

Complete

Complete

Retina

F4/80

Complete

Complete

b

Peritoneal cavity

NSE

Complete

Nonec

Pleural cavity

NSE

Complete

Nonec

Lymph node subcap. sinus

CD11b

Complete

±

Adrenals

F4/80

Partial

None

Bladder

F4/80

Partial

Partial/nonea

Salivary gland

F4/80

Partial

Partial

Bone marrow macrophage

F4/80

Partial

Partial

Liver

F4/80

Partial

Complete

Partial

±

Lung alveolar macrophage Osteoclast

b

WS

b

TRAP

Completea

Partial d

Partial/nonea

Stomach

F4/80

Partial

Gut

F4/80

Partial

Partial/nonea

Spleen

F4/80

Partial

Complete

Uterus

F4/80

Partial

±

Langerhans

F4/80

Independent

None

Thymus

F4/80

Independent

None

Lymph node

F4/80

Independent

None

Bone marrow `monocyte'

F4/80

Independent

None

Spleen metallophils

MOMA-1

Complete

Complete

References: Cecchini et al. (1994); Pollard and Stanley (1996); Wiktor-Jedrzejczak and Gordon (1996). a Localized subpopulations exhibited different responses to restoration of circulating CSF-1. b NSE, nonspecific esterase; WS, Wright's stain; TRAP, tartrate-resistant acid phosphatase. c Local administration of CSF-1 restores subpopulation. d Localized subpopulations within these tissues are completely dependent.

regulation of pre- and postimplantation development in the female reproductive tract. Studies with the op/ op mouse (Pollard and Stanley, 1996), summarized below, have indicated that this is the case and that CSF-1 surprisingly also plays an important role in the regulation of male fertility. Both CSF-1 and CSF-1R mRNA are expressed in the brain in a developmentally regulated way and

CSF-1 mRNA is expressed in a regional specific pattern (Michaelson et al., 1996). CSF-1 appears to play a role in the wound healing processes in the brain (Brosnan et al., 1993) and probably indirectly, via its action on microglia, in sensory responses. Although autocrine regulation by CSF-1 may be involved in some situations, such as myoblast differentiation (Borycki et al., 1995) and the effect of IL-1

922 E. Richard Stanley on human monocyte survival and differentiation (Gruber et al., 1994), CSF-1 normally acts on nonCSF-1-producing cells. In contrast, autocrine regulation by CSF-1 is quite common in neoplasia. Mouse monocytic tumors induced by a c-myc-containing retrovirus were shown to develop due to a rearrangement in the CSF-1 gene which resulted in their secretion of CSF-1 and autocrine regulation (Baumbach et al., 1987). Furthermore, the proliferation of individual radiation-induced leukemias in SJL/J mice has been shown without exception to be regulated in an autocrine fashion by CSF-1 (Haran-Ghera et al., 1997). Autocrine regulation of proliferation by CSF-1 has also been reported for human placental (Takeda et al., 1996) and hematopoietic (Champelovier et al., 1997) cell lines. CSF-1 has been shown to enhance the uptake and degradation of acetylated LDL and cholesterol esterification by macrophages in vitro, and its expression with CSF-1R-expressing foam cells in atherosclerotic lesions (Wiktor-Jedrzejczak and Gordon, 1996; Motoyoshi, 1998), together with studies in Csf1op/ Csf1op mice (de Villiers et al., 1998; Rajavashisth et al., 1998), indicate that it plays a role in the pathogenesis of atherosclerosis.

Species differences Human CSF-1 is active on mouse cells but mouse CSF-1 has no activity on human cells.

(Wiktor-Jedrzejczak et al., 1990; Yoshida et al., 1990). Sequencing of the Csf1op/Csf1op cDNA revealed that this deficiency is due to a thymidine insertion in exon 4 (Yoshida et al., 1990) and that this was the only mutation in the coding sequence (Pollard et al., 1991). The thymidine insertion leads to a frameshift at base pair 262 from the ATG initiation codon of the CSF-1 cDNA sequence, predicting translational termination 21 bp downstream and a translation product of 63 amino acids, considerably shorter than the 150 amino acids required for CSF-1 biological activity (Kawasaki and Ladner, 1990). Although initially the mutation appeared to be completely recessive (Wiktor-Jedrzejczak et al., 1990), recent studies of mice bearing the mutation on a more uniform genetic background indicate that heterozygotes have lower CSF-1 concentrations than homozygous wild-type mice (Rajavashisth et al., 1998). The pleiotropic phenotype of the Csf1op/Csf1op mouse is summarized in Table 3. Their lack of osteoclasts leads to the prenatal and early postnatal absence of a distinct bone marrow medullary cavity, Table 3 Phenotype of young Csflop/Csflop mice Osteopetrosis due to reduced number of osteoclasts Reduced bone marrow cellularity Increased extramedullary hematopoiesis Reduced numbers of tissue macrophages (Table 2)

Knockout mouse phenotypes No targeted gene inactivation of CSF-1 has been reported. However, the osteopetrotic mutation, Csf1op, formerly known as op (Marks and Lane, 1976), behaves as a CSF-1-null mutation. Reciprocal bone marrow transplantation experiments showed that op is cell nonautonomous, indicating that the mutation affected the production of a growth stimulatory or inhibitory factor regulating the osteoclastic lineage (Wiktor-Jedrzejczak et al., 1982, 1990). Besides their osteopetrosis, the Csf1op/Csf1op mutants were found to possess a profound deficiency in mononuclear phagocytes and the CSF-1 gene was subsequently found to map near the Csf1op locus on chromosome 3 (Pollard and Stanley, 1996). These observations, which suggested that Csf1op could be a mutation in the CSF-1 gene, were supported by the absence of CSF-1 in a wide range of Csf1op/ Csf1op tissues and serum by RIA and the inability of Csf1op/Csf1op bone marrow stroma to support mononuclear phagocytic colony formation in vitro

Reduced atherosclerosis when hyperlipidemic Female reproductive defects Extended estrus cycle Delayed puberty Low ovulation rate Reduced litter size Reduced lactational ability Disrupted positive and negative feedback loops in hypothalamus and pituitary Male reproductive defects Reduced testosterone production Low libido Lowered circulating LH concentration Reduced hypothalamic-pituitary feedback response to testosterone Reduced auditory and visual processing Toothlessness Reduced weight

CSF-1 domed skulls, sclerosis of the vertebrae, shortened limb and tail bones, as well as frequent deformities of the hind feet and tail. As indicated above, marrow cavities do develop in older mice, but most of the skeletal abnormalities associated with the osteopetrotic condition persist. In addition the mice are toothless, have a low body weight, poor breeding performance, thinner than normal dermis, and are functionally deaf and blind (Felix et al., 1994; Pollard and Stanley, 1996; Wiktor-Jedrzejczak and Gordon, 1996). Besides reduced numbers of osteoclasts, young Csf1op/Csf1op mice possess lower than normal numbers of bone marrow macrophages, blood monocytes, serosal cavity macrophages, and tissue macrophages in most tissues (Cecchini et al., 1994; Pollard and Stanley, 1996). Although bone marrow cellularity is dramatically lowered due to the reduction in the available marrow space, the numbers of lightly staining F4/80‡ monocytic cells (candidate blood monocyte precursors) (Felix et al., 1990; Cecchini et al., 1994) are differentially increased, consistent with a block in mononuclear phagocyte differentiation. The reduced bone marrow hematopoiesis and mononuclear phagocyte differentiation block at 2±6 weeks of age is associated with a compensatory increase in splenic hematopoiesis (Nilsson and Bertoncello, 1994). However, due to slow osteoclast development, there is progressive enlargement of the bone cavities with age and hematopoiesis gradually switches back to the marrow, bone marrow cellularity normalizing by 22 weeks, and F4/80‡ macrophage numbers by 35 weeks of age (Begg et al., 1993; Nilsson et al., 1995). The age-related correction of osteopetrosis and hematopoiesis is not accompanied by a recovery of liver Kupffer cells (Cecchini et al., 1994; Takatsuka et al., 1998) and is likely to be due to local production of VEGF-1, which can independently stimulate osteoclastogenesis in op/op mice (Niida et al., 1999). Consistent with the different morphologies of macrophages cultured with GM-CSF and CSF-1, the CSF-1-dependent tissue macrophage populations of the Csf1op/Csf1op mouse are more round and possess less developed organelles than macrophages from normal mice (Pollard and Stanley, 1996). Csf1op/Csf1op mice are able to mount normal T and B cell-dependent responses both to simple antigens, such as ovalbumin, or a corpuscular antigen, such as sheep red blood cells (WiktorJedrzejczak et al., 1992; Chang et al., 1995), consistent with the nearly normal development of lymph node, thymic, and splenic macrophages and the normal numbers of dendritic cells (Witmer-Pack et al., 1993; Cecchini et al., 1994). In addition to these normal T and B cell functions, Csf1op/Csf1op mice exhibit

923

normal delayed hypersensitivity responses and phagocytosis of carbon particles (Wiktor-Jedrzejczak et al., 1992). Successful pregnancies from Csf1op/Csf1op  Csflop/ Csflop matings are very infrequent, because Csf1op/ Csf1op males have a low libido and Csf1op/Csf1op females have extended, somewhat abnormal estrus cycles (Cohen et al., 1996, 1997). The males have low circulating levels of luteinizing hormone (LH), reduced testosterone synthesis, and low sperm counts associated with a reduced complement of testicular macrophages, all of which are partially correctable by restoration of circulating CSF-1 (Cohen et al., 1997a; Pollard et al., 1997). Since macrophages are the only CSF-1R-expressing cells in the hypothalamus and testes, and the testis macrophages are in intimate contact with the steroid biosynthetic Leydig cells, these data suggest that CSF-1 affects testicular steroidogenesis through its regulation of the development of hypothalamic and testicular macrophages that are respectively trophic for luteinizing hormone synthesis and Leydig cell steroidogenesis. CSF-1 is not required for placental development (Pollard et al., 1991) and female Csf1op/Csf1op mice display fertility defects at three levels. First, they have a reduced ovulation rate and reduced numbers of ovarian macrophages, both of which are corrected by restoration of circulating levels of CSF-1 from birth (Araki et al., 1996; Cohen et al., 1997b). Since estrogen drives ovarian function, these mice either lack ovarian responsiveness to pituitary gonadotropins or have a lower rate of steroidogenesis, regulated by CSF-1 either directly or via its action on macrophages. Second, they have a slightly greater rate of fetal attrition (Pollard et al., 1991). Third, their mammary glands fail to branch and grow out into the fat pad during pregnancy. Restoration of circulating CSF-1 is able to partially correct this lactational defect and approximately 50% of mothers feed their young (Pollard and Hennighausen, 1994). The action of CSF-1 could be either within the mammary gland, directly on ductal epithelial cells or via resident macrophages, or it could act indirectly by influencing another tissue, e.g. placenta, to produce a hormone or cytokine that regulates mammary gland growth and development (Cohen et al., 1999). Csf1op/Csf1op mice have a slow response to external stimuli suggestive of neuronal deficiencies. Electrophysiological scalp recordings of both brainstem auditory evoked potentials and visual evoked potentials (VEP) confirmed diminished neurological function in these sensory responses. However, Csf1op/Csf1op brains are normal in size and have no obvious histological abnormalities (Michaelson et al., 1996), apart from a significant lowering of

924 E. Richard Stanley Figure 3 Regulation by CSF-1 of target cells that have trophic and/or scavenger roles in tissues.

microglial cell density and altered microglial cell morphology (Wegiel et al., 1998). As expected from the regulation of microglial proliferation by CSF-1, microglial proliferation in the facial nucleus is dramatically reduced compared with wild-type mice following axotomization of the facial nerve (Raivich et al., 1994), consistent with a role for CSF-1 in posttraumatic repair processes within the brain. Csf1op/Csf1op mice fed a high-fat, high-cholesterol diet or on an apoprotein E-null background, have significantly reduced atherosclerosis compared with wildtype control mice (Qiao et al., 1997; de Villiers et al., 1998; Rajavashisth et al., 1998). An approximately 2-fold reduction in CSF-1 expression (from ‡/‡ to op/‡) reduced lesion size by approximately 100-fold, suggesting the requirement for a threshold level of CSF-1. However, since both op/op and op/‡ mice exhibited higher levels of atherogenic lipoprotein particles and (op/‡) mice showed a near normal number of circulating monocytes, these results suggest that locally produced CSF-1 may be involved in the development of atherosclerosis (Rajavashisth et al., 1998). In general, it appears that macrophages requiring either locally produced or circulating CSF-1 for their establishment or maintenance appear to have trophic or scavenger roles important in organogenesis and tissue remodeling, distinguishing them from the `CSF-1-independent macrophages' that are primarily involved in immune and inflammatory responses. In fact, the pleiotropic nature of the Csf1op/Csf1op phenotype appears to be a direct consequence of the lack of the physiologically active macrophage populations whose development and maintenance are regulated by CSF-1 (Cecchini et al., 1994) (Figure 3). Current understanding of regulation by CSF-1, partly summarized in Figure 4 and Figure 5, is largely due to studies with Csf1op/Csf1op mice.

Figure 4 Humoral and local regulation by CSF-1: macrophage and osteoclast production and function. pp, primitive multipotent progenitor cell; mp, multipotent progenitor cell; mp, mononuclear phagocyte progenitor; mo, monocyte; m, macrophage; ob/sc, osteoblast/stomal cell; op, osteoclast progenitor; oc, osteoclast; ec, endothelial cell; kc, Kupffer cell; csc, CSF-1 synthesizing cell; tc, tissue cell.

CSF-1 Figure 5 Humoral and local regulation by CSF-1: the reproductive system. LC, Leydig cell; M, macrophage; OF, ovarian follicle; MG, microglial cell; AP, anterior pituitary; H, hypothalamus; LH, luteinizing hormone, T, testosterone; E2, estrogen. Modified from Cohen et al. (1999).

925

Interactions with cytokine network See sections on In vitro findings and Regulatory molecules: inhibitors and enhancers.

Endogenous inhibitors and enhancers See section on Regulatory molecules: inhibitors and enhancers.

PATHOPHYSIOLOGICAL ROLES IN NORMAL HUMANS AND DISEASE STATES AND DIAGNOSTIC UTILITY

Normal levels and effects Pharmacological effects The concentration of CSF-1 in mouse serum varies from 7 to 15 ng/mL depending on the strain. Ninety-four per cent of circulating mouse CSF-1 (half-life, 10 minutes) is cleared by CSF-1R-mediated endocytosis and intracellular degradation by sinusoidally located macrophages in the liver and spleen. CSF-1 clearance by macrophages represents a negative feedback loop for macrophage production regulated by circulating CSF-1 (Bartocci et al., 1987). Superimposed upon this coarse control, rapid increases in circulating CSF-1 in response to stimuli and infections are mediated by the increased synthesis and release of the growth factor by endothelial cells of several organs (Roth et al., 1997). Administration of pharmacological doses of CSF-1 can saturate the physiological clearance mechanism, resulting in clearance by the kidney and extension of the serum half-life to 1.6 hours (Bartocci et al., 1987). Administration of recombinant human CSF-1 in mice and nonhuman primates results in an increase of up to 10-fold in the circulating monocyte concentration and increases in macrophage numbers in certain areas of the periphery (Hume et al., 1988; Munn et al., 1990). CSF-1 administration to hyperlipidemic rabbits or cynomolgus monkeys rapidly lowers blood cholesterol levels (Shimano et al., 1990; Stoudemire and Garnick, 1991).

Serum levels of CSF-1 in normal adults have a mean value of 4.46  1.33 ng/mL (n=64) and range from 1.73 to 8.4 ng/mL (Janowska-Wieczorek et al., 1991). Serum CSF-1 levels are significantly elevated in pregnancy (Daiter and Pollard, 1992). Compared with adults, levels are elevated in the newborn (Roth and Stanley, 1992). Approximately one-third of people over the age of 65, while possessing normal serum levels, have elevated urinary levels (Liao et al., 1994).

Role in experiments of nature and disease states Circulating CSF-1 is elevated in a variety of conditions, in many cases consistent with our understanding of CSF-1 biology. High concentrations are seen in patients with a variety of neoplastic disorders of the hematopoietic and reproductive systems. Consistent with the role of CSF-1 in pregnancy, circulating levels are elevated in patients with preeclampsia (Hayashi et al., 1996) and depressed in patients with unexplained recurrent abortion (Katano et al., 1997). Serum CSF-1 is elevated in patients following chemotherapy with and without autologous bone marrow transplantation (Kimura et al., 1992; Rabinowitz et al., 1993) and during infection (Cebon et al., 1994; Petros et al., 1994; Grieg and Roth, 1995). Serum levels are also increased in liver disease (Itoh et al., 1994, 1997) and hepatic injury (Itoh et al., 1999), hemophagocytic syndrome (Shirono and Tsuda,

926 E. Richard Stanley 1995), thalassemia (Wiener et al., 1996), amyloidosis (Rysava et al., 1999), and in patients surmised to have had vascular damage due to a previous cerebral infarction (Suehiro et al., 1999). Consistent with the increased CSF-1 mRNA expression in ischemic and reperfused myocardium (Frangogiannis et al., 1998), circulating CSF-1 is elevated in ischemic heart disease (Tashiro et al., 1997). Patients with IgA nephropathy possess normal serum but elevated urinary CSF-1 levels (Matsuda et al., 1999). Both high-grade cervical dysplasia patients and human papillomavirus-infected women at high risk have increased serum CSF-1 concentrations, suggesting a possible role for CSF-1 in cervical neoplasia (Adam et al., 1999). Elevated circulating CSF-1 has been suggested as a disease marker for ovarian cancer, endometrial cancer, and breast cancer (Kacinski, 1995; Scholl et al., 1996), and for amyloidosis (Rysava et al., 1999). Inappropriate coexpression of both CSF-1 and the CSF-1R in the same cell type and consequent autocrine regulation by the growth factor may lead to tumor development (Baumbach et al., 1987). Coexpression of both CSF-1 and the CSF-1R has been described for human adenocarcinomas of the endometrium, ovary and breast, as well as leukemias (Kacinski, 1995; Haran-Ghera et al., 1997). In addition, many patients with neoplasms of these types possess significantly elevated concentrations of circulating CSF-1 (Janowska-Wieczorek et al., 1991; Kacinski, 1995; Scholl et al., 1996; Haran-Ghera et al., 1997). These neoplasms are therefore candidates for autocrine or paracrine regulation by CSF-1. CSF-1 plays an important role in the pathogenesis of atherosclerosis in humans (reviewed in Motoyoshi, 1998).

IN THERAPY Potential therapeutic applications of CSF-1 include its use in the treatment of infection and malignancies, to accelerate hematopoietic recovery following chemotherapy or bone marrow transplantation, to reduce the risk of atherosclerosis and to improve fertility. The development of effective antagonists is another potential area of application, because of the elevation of circulating and/or local CSF-1 in specific chronic diseases.

Preclinical ± How does it affect disease models in animals? Administration of pharmacological doses of mouse or human CSF-1 has been reported to increase

circulating monocytes and granulocytes and tissue macrophages. Stimulation of the cycling of bone marrow progenitors and the splenic content of progenitors for granulocytes, megakaryocytes, and erythrocytes was also reported and may reflect the synergism observed between CSF-1 and other hematopoietic cytokines on primitive progenitors in vitro. In other early studies, CSF-1 has been reported to stimulate NK cell activity, macrophage and monocyte antibody-dependent cellular cytotoxicity, to protect against lethal Escherichia coli and Candida infection in normal and cytoxan-suppressed mice and to reduce tumor metastases and increase survival in mice bearing B16 melanomas. It was shown to synergize with IFN and local irradiation in the treatment of mice with B16 tumors and Lewis carcinomas. (Garnick and Stoudemire, 1990; Ralph and Sampson-Johannes, 1990; Munn and Cheung, 1992). More recently, a variety of model systems have been used to demonstrate antitumor and/or antimetastatic effects of CSF-1 either alone (Sanda et al., 1992; Sasaki et al., 1995) or in conjunction with other treatments including cytokines (Vallera et al., 1993; Lasek et al., 1995; Teicher et al., 1996), antibodies to tumor antigens (Conlon et al., 1996), and chemotherapy (Adachi et al., 1993; Douzono et al., 1995). In addition, treatment of rodents with tumor cells transduced with the gene encoding either the secreted or cell surface form of CSF-1 has been shown to have antitumor effects, often associated with a marked macrophage infiltration into the tumor (Sone et al., 1996; Yoshioka et al., 1998; Graf et al., 1999; Yano et al., 1999). In agreement with the in vitro observations (Bartelmez and Stanley, 1985; Jubinsky, 1985; Stanley et al., 1986), combined treatment of mice with IL-1 and CSF-1 has been shown to be particularly effective in accelerating hematopoietic recovery from drug-induced myelosuppression in mice (Kovacs et al., 1998). Inclusion of secondary cytokines, IL-3, GMCSF, and IL-6 further enhances the effect of IL-1 and CSF-1 (Kovacs et al., 1997). Infusion of CSF-1 into rabbits and nonhuman primates reduces serum cholesterol, by enhancement of the clearance of lipoproteins containing apolipoprotein B-100 via both LDL receptor-dependent and independent pathways. CSF-1 increases the uptake of acetylated LDL into macrophages by upregulating scavenger receptors. However, it also stimulates an efflux of free LDL from macrophages by upregulating both the HDL receptor and cholesterol ester hydrolase. Indeed, the accumulation of cholesterol ester and the density of macroscopic plaques containing the CSF-1-receptor-expressing foam cells are both significantly decreased in the aortas of CSF-1-treated

CSF-1 Watanabe heritable hyperlipidemic rabbits, suggesting that while threshold levels are required for the development of the lesions (Rajavashisth et al., 1998), high circulating CSF-1 inhibits progression of atherosclerosis by influencing macrophage function (Motoyoshi, 1998). Other reported effects of CSF-1 administration include the suppression of acute virus-induced myocarditis (Hiraoka et al., 1995) and suppression of the infiltration of glomerular macrophages in lipidinduced nephrotoxicity in hypercholesteremic diabetic rats (Utsunomiya et al., 1995).

Pharmacokinetics Reflecting the situation in mice (Bartocci et al., 1987), dose-range studies with human recombinant CSF-1 in rats showed a drop in serum half-life from 23 minutes to  10 hours with increased dose from 5 to 1000 mg/ kg (Garnick and Stoudemire, 1990). Continued administration of pharmacological doses of CSF-1 in monkeys lowers the CSF-1 half-life from 6.2 hours to 2 hours (Garnick and Stoudemire, 1990), presumably by increasing (Cecchini et al., 1994) the numbers of sinusoidally located liver and splenic macrophages that have been shown to clear CSF-1 at physiological concentrations in mice (Bartocci et al., 1987). A decreased half-life after administration of pharmacological doses is also seen in humans (Cole et al., 1994).

927

certain chronic neutropenias of childhood, in decreasing serum cholesterol and in significantly decreasing the recovery times from granulocytopenia and in increasing the survival rates in patients given CSF-1 after bone marrow transplantation. In subsequent studies, human recombinant CSF-1, given to acute myeloid leukemic patients in complete remission after combination chemotherapy, was shown to reduce the average durations of pyrexia, the requirement for parenteral antibiotic injections, and the number of platelet transfusions (Motoyoshi, 1998). In a largescale double-blind study with human urinary CSF-1 administered to acute myeloid leukemiapatients in complete remission for 14 days after each consolidation therapy, similar effects were observed, with faster recovery of neutrophils and platelets and reduction in febrile neutropenia (Ohno et al., 1997). As for treatment with the other CSFs, patients who have received CSF-1 after chemotherapy tend to have a higher complete remission rate, but this does not seem to translate into a definite survival benefit (Ohno, 1998). Based on the preclinical studies (Kovacs et al., 1998), additional trials with CSF-1 in combination with other cytokines are warranted. Phase I trials of recombinant human CSF-1 in combination with standard antifungal therapy in patients with invasive fungal infections following bone marrow transplantation suggest efficacy of CSF-1 in controlling fungal infections (Nemunaitis, 1998).

Toxicity

References

Phase 1 trials of CSF-1 indicate that it is mildly toxic, occasionally inducing flu-like symptoms and exhibiting a reversible but sometimes dose-limiting thrombocytopenia (Vial and Descotes, 1995). Preclinical experiments indicate that the thrombocytopenia is transient and not due to suppression of thrombopoiesis, but to increased numbers and activity of macrophages, causing shortened platelet survival times. The thrombocytopenia persists until increased platelet production compensates for the increased platelet destruction (Baker and Levin, 1998).

Adachi, T., Mano, H., Shinohara, Y., Nakanishi, T., Suzuki, T., Ino, K., Kato, N., Okamoto, T., Nawa, A., and Goto, S. (1993). Tumoricidal effect of human macrophage-colony-stimulating factor against human-ovarian-carcinoma-bearing athymic mice and its therapeutic effect when combined with cisplatin. Cancer Immunol. Immunother. 37, 1±6. Adam, R. A., Horowitz, I. R., and Tekmal, R. R. (1999). Serum levels of macrophage colony-stimulating factor-1 in cervical human papillomavirus infection and intraepithelial neoplasia. Am. J. Obstet. Gynecol. 180, 28±32. Allen, W. E., Zicha, D., Ridley, A. J., and Jones, G. E. (1998). A role for Cdc42 in macrophage chemotaxis. J. Cell Biol. 141, 1147±1157. Araki, M., Fukumatsu, Y., Katabuchi, H., Shultz, L. D., Takahashi, K., and Okamura, H. (1996). Follicular development and ovulation in macrophage colony-stimulating factordeficient mice homozygous for the osteopetrosis (op) mutation. Biol. Reprod. 54, 478±484. Arceci, R. J., Shanahan, F., Stanley, E. R., and Pollard, J. W. (1989). Temporal expression and location of colony-stimulating factor 1 (CSF-1) and its receptor in the female reproductive tract are consistent with CSF-1-regulated placental development. Proc. Natl Acad. Sci. USA 86, 8818±8822. Arceci, R. J., Pampfer, S., and Pollard, J. W. (1992). Role and expression of colony stimulating factor-1 and steel factor

Clinical results In several early phase I and phase II studies, the administration of human urinary CSF-1 was reported to be efficacious in stimulating leukocyte recovery and reducing thrombocytopenia of patients with solid tumors after chemotherapy, in increasing the number and maturity of marrow neutrophil precursors in

928 E. Richard Stanley receptors and their ligands during pregnancy in the mouse. Reprod. Fertil. Dev. 4, 619±632. Asakura, E., Yamauchi, T., Umemura, A., Hanamura, T., and Tanabe, T. (1997). Intravenously administered macrophage colony-stimulating factor (M-CSF) specifically acts on the spleen, resulting in the increasing and activating spleen macrophages for cytokine production in mice. Immunopharmacology 37, 7±14. Baker, G. R., and Levin, J. (1998). Transient thrombocytopenia produced by administration of macrophage colony-stimulating factor: investigations of the mechanism. Blood 91, 89±99. Bartelmez, S. H., and Stanley, E. R. (1985). Synergism between hemopoietic growth factors (HGFs) detected by their effects on cells bearing receptors for a lineage specific HGF: assay of hemopoietin-1. J. Cell. Physiol. 122, 370±378. Bartelmez, S. H., Bradley, T. R., Bertoncello, I., Mochizuki, D. Y., Tushinski, R. J., Stanley, E. R., Hapel, A. J., Young, I. G., Kriegler, A. B., and Hodgson, G. S. (1989). Interleukin 1 plus interleukin 3 plus colony-stimulating factor 1 are essential for clonal proliferation of primitive myeloid bone marrow cells. Exp. Hematol. 17, 240±245. Bartocci, A., Pollard, J. W., and Stanley, E. R. (1986). Regulation of colony-stimulating factor 1 during pregnancy. J. Exp. Med. 164, 956±961. Bartocci, A., Mastrogiannis, D. S., Migliorati, G., Stockert, R. J., Wolkoff, A. W., and Stanley, E. R. (1987). Macrophages specifically regulate the concentration of their own growth factor in the circulation. Proc. Natl Acad. Sci. USA 84, 6179±6183. Baumbach, W. R., Stanley, E. R., and Cole, M. D. (1987). Induction of clonal monocyte-macrophage tumors in vivo by a mouse c-myc retrovirus: rearrangement of the CSF-1 gene as a secondary transforming event. Mol. Cell. Biol. 7, 664±671. Bazan, J. F. (1991). Genetic and structural homology of stem cell factor and macrophage colony-stimulating factor. Cell 65, 9±10. Begg, S. K., Radley, J. M., Pollard, J. W., Chisholm, O. T., Stanley, E. R., and Bertoncello, I. (1993). Delayed hematopoietic development in osteopetrotic (op/op) mice. J. Exp. Med. 177, 237±242. Ben Avram, C. M., Shively, J. E., Shadduck, R. K., Waheed, A., Rajavashisth, T., and Lusis, A. J. (1985). Amino-terminal amino acid sequence of murine colony-stimulating factor 1. Proc. Natl Acad. Sci. USA 82, 4486±4489. Bennett, S., Por, S. B., Stanley, E. R., and Breit, S. N. (1992). Monocyte proliferation in a cytokine-free, serum-free system. J. Immunol. Methods 153, 201±212. Boocock, C. A., Jones, G. E., Stanley, E. R., and Pollard, J. W. (1989). Colony-stimulating factor-1 induces rapid behavioural responses in the mouse macrophage cell line, BAC1.2F5. J. Cell Sci. 93, 447±456. Borrello, M. A., and Phipps, R. P. (1999). Fibroblast-secreted macrophage colony-stimulating factor is responsible for generation of biphenotypic B/macrophage cells from a subset of mouse B lymphocytes. J. Immunol. 163, 3605±3611. Borycki, A., Lenormund, J., Guillier, M., and Leibovitch, S. A. (1993). Isolation and characterization of a cDNA clone encoding for rat CSF-1 gene.Post-transcriptional repression occurs in myogenic differentiation. Biochim. Biophys. Acta 1174, 143±152. Borycki, A.-G., Foucrier, J., Saffar, L., and Leibovitch, S. A. (1995a). Repression of the CSF-1 receptor (c-fms proto-oncogene product) by antisense transfection induces G1-growth arrest in L6a1 rat myoblasts. Oncogene 10, 1799±1811. Borycki, A.-G., Lenormand, J.-L., Guillier, M., Smadja, F., Stanley, E. R., and Leibovitch, S. A. (1995b). Co-expression of CSF-1 and its receptor on myoblasts is lost on their differentiation to myotubes. Exp. Cell Res. 218, 213±222.

Borycki, A.-G., Smadja, F., Stanley, R., and Leibovitch, S. A. (1995c). Colony-stimulating factor 1 (CSF-1) is involved in an autocrine growth control of rat myogenic cells. Exp. Cell Res. 218, 213±222. Bot, F. J., van Eijk, L., Broeders, L., Aarden, L. A., and Lowenberg, B. (1989). Interleukin-6 synergizes with M-CSF in the formation of macrophage colonies from purified human marrow progenitor cells. Blood 73, 435±437. Brosnan, C. F., Shafit-Zagardo, B., Aquino, D. A., and Berman, J. W. (1993). Expression of monocyte/macrophage growth factors and receptors in the central nervous system. Adv. Neurol. 59, 349±361. Cebon, J., Layton, J. E., Maher, D., and Morstyn, G. (1994). Endogenous haemopoietic growth factors in neutropenia and infection. Br. J. Haematol. 86, 265±274. Cecchini, M. G., Dominguez, M. G., Mocci, S., Wetterwald, A., Felix, R., Fleisch, H., Chisholm, O., Hofstetter, W., Pollard, J. W., and Stanley, E. R. (1994). Role of colony stimulating factor-1 in the establishment and regulation of tissue macrophages during postnatal development of the mouse. Development 120, 1357±1372. Cerretti, D. P., Wignall, J., Anderson, D., Tushinski, R. J., Gallis, B. M., Stya, M., Gillis, S., Urdal, D. L., and Cosman, D. (1988). Human macrophage-colony stimulating factor: alternative RNA and protein processing from a single gene. Mol. Immunol. 25, 761±770. Champelovier, P., Fixe, P., Valiron, O., Feige, J. J., Praloran, V., and Seigneurin, D. (1997). Proliferation of LAMA-84 and LAMA-87 cell lines is modulated by autocrine loops involving M-CSF and TGF-beta. Exp. Hematol. 25, 958±965. Chang, M. Y., Stanley, E. R., Khalili, H., Chisholm, O., and Pollard, J. W. (1995). Osteopetrotic (op/op) mice deficient in macrophages have the ability to mount a normal T-cell-dependent immune response. Cell. Immunol. 162, 146±152. Chang, M. Y., Olin, K. L., Tsoi, C., Wight, T. N., and Chait, A. (1998). Human monocyte-derived macrophages secrete two forms of proteoglycan-macrophage colony-stimulating factor that differ in their ability to bind low density lipoproteins. J. Biol. Chem. 273, 15985±15992. Cheers, C., Hill, M., Haigh, A. M., and Stanley, E. R. (1989). Stimulation of macrophage phagocytic but not bactericidal activity by colony-stimulating factor 1. Infect. Immun. 57, 1512± 1516. Clinton, S. K., Underwood, R., Hayes, L., Sherman, M. L., Kufe, D. W., and Libby, P. (1992). Macrophage colony-stimulating factor gene expression in vascular cells and in experimental and human atherosclerosis. Am. J. Pathol. 140, 301±316. Cohen, P. E., Chisholm, O., Arceci, R. J., Stanley, E. R., and Pollard, J. W. (1996). Absence of colony-stimulating factor-1 in osteopetrotic (csfmop/csfmop) mice results in male fertility defects. Biol. Reprod. 55, 310±317. Cohen, P. E., Hardy, M. P., and Pollard, J. W. (1997a). Colonystimulating factor-1 plays a major role in the development of reproductive function in male mice. Mol. Endocrinol. 11, 1636± 1650. Cohen, P. E., Zhu, L. Y., and Pollard, J. W. (1997b). Absence of colony stimulating factor-1 in osteopetrotic (csfmop/csfmop) mice disrupts estrous cycles and ovulation. Biol. Reprod. 56, 110±118. Cohen, P. E., Nishimura, K., Zhu, L., and Pollard, J. W. (1999). Macrophages: important accessory cells for reproductive function. J. Leukoc. Biol. 66, 765±772. Cole, D. J., Sanda, M. G., Yang, J. C., Schwartzentruber, D. J., Weber, J., Ettinghausen, S. E., Pockaj, B. A., Kim, H. I., Levin, R. D., Pogrebniak, H. W., Balkissoon, J., Fenton, R. M., DeBarge, L. R., Kaye, J., Rosenberg, S. A., and Parkinson, D. R.

CSF-1 (1994). Phase I trial of recombinant human macrophage colonystimulating factor administered by continuous intravenous infusion in patients with metastatic cancer. J.Natl Cancer Inst. 6, 39±45. Conlon, K. C., Anver, M. R., Longo, D. L., Ortaldo, J. R., and Murphy, W. J. (1996). Adoptive immunotherapy involving recombinant human M-CSF and R24 anti-melanoma antibody induces human T-cell infiltration into human melanoma xenografts. J. Immunother. Emphasis Tumor Immunol. 19, 317±323. Daiter, E., and Pollard, J. W. (1992). Colony stimulating factor-1 (CSF-1) in pregnancy. Reprod. Med. Rev. 1, 83±97. Das, S. K., Stanley, E. R., Guilbert, L. J., and Forman, L. W. (1980). Discrimination of a colony stimulating factor subclass by a specific receptor on a macrophage cell line. J. Cell. Physiol. 104, 359±366. Das, S. K., Stanley, E. R., Guilbert, L. J., and Forman, L. W. (1981). Human colony stimulating factor (CSF-1) radioimmunoassay: resolution of three subclasses of human colony stimulating factors. Blood 58, 630±641. De Villiers, W. J. S., Fraser, I. P., and Gordon, S. (1994). Cytokine and growth factor regulation of macrophage scavenger receptor expression and function. Immunol. Lett. 43, 73±79. de Villiers, W. J., Smith, J. D., Miyata, M., Dansky, H. M., Darley, E., and Gordon, S. (1998). Macrophage phenotype in mice deficient in both macrophage-colony-stimulating factor (op) and apolipoprotein E. Arterioscler. Thromb. Vasc. Biol. 18, 631±640. DeLamarter, J. F., Hession, C., Semon, D., Gough, N. M., Rothenbuhler, R., and Mermod, J.-J. (1987). Nucleotide sequence of a cDNA encoding murine CSF-1 (macrophageCSF). Nucleic Acids Res. 15, 2389±2390. Deng, P., Wang, Y. L., Haga, Y., and Pattengale, P. K. (1998). Multiple factors determine the selection of the ectodomain cleavage site of human cell surface macrophage colony-stimulating factor. Biochemistry 37, 17898±17904. Douzono, M., Suzu, S., Yamada, M., Yanai, N., Kawashima, T., Hatake, K., and Motoyoshi, K. (1995). Augmentation of cancer chemotherapy by preinjection of human macrophage colonystimulating factor in L1210 leukemic cell-inoculated mice. Jpn J. Cancer Res. 86, 315±321. Felix, R., Cecchini, M. G., Hofstetter, W., Elford, P. R., Stutzer, A., and Fleisch, H. (1990). Impairment of macrophage colony-stimulating factor production and lack of resident bone marrow macrophages in the osteopetrotic op/op mouse. J. Bone Miner. Res. 5, 781. Felix, R., Hofstetter, W., Wetterwald, A., Cecchini, M. G., and Fleisch, H. (1994). Role of colony-stimulating factor-1 in bone metabolism. J. Cell. Biochem. 55, 340±349. Filderman, A. E., Bruckner, A., Kacinski, B. M., Deng, N., and Remold, H. G. (1992). Macrophage colony-stimulating factor (CSF-1) enhances invasiveness in CSF-1 receptor-positive carcinoma cell lines. Cancer Res. 52, 3661±3666. Frangogiannis, N. G., Youker, K. A., Rossen, R. D., Gwechenberger, M., Lindsey, M. H., Mendoza, L. H., Michael, L. H., Ballantyne, C. M., Smith, C. W., and Entman, M. L. (1998). Cytokines and the microcirculation in ischemia and reperfusion. J. Mol. Cell. Cardiol. 30, 2567± 2576. Fuller, K., Owens, J. M., Jagger, C. J., Wilson, A., Moss, R., and Chambers, T. J. (1993). Macrophage colony-stimulating factor stimulates survival and chemotactic behavior in isolated osteoclasts. J. Exp. Med. 178, 1733±1744. Garnick, M. B., and Stoudemire, J. B. (1990). Preclinical and clinical evaluation of recombinant human macrophage colonystimulating factor (rhM-CsF). Int. J. Cell Cloning 8, 356±373.

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Glocker, M. O., Arbogast, B., Schreurs, J., and Deinzer, M. L. (1993). Assignment of the inter- and intramolecular disulfide linkages in recombinant human macrophage colony stimulating factor using fast atom bombardment mass spectrometry. Biochemistry 32, 482±488. Graf, M. R., Jadus, M. R., Hiserodt, J. C., Wepsic, H. T., and Granger, G. A. (1999). Development of systemic immunity to glioblastoma multiforme using tumor cells genetically engineered to express the membrane-associated isoform of macrophage colony-stimulating factor. J. Immunol. 163, 5544± 5551. Grieg, A., and Roth, P. (1995). Colony-stimulating factor 1 in the human response to neonatal listeriosis. Infect Immun. 63, 1595± 1597. Gruber, M. F., Williams, C. C., and Gerrard, T. L. (1994). Macrophage-colony-stimulating factor expression by antiCD45 stimulated human monocytes is transcriptionally upregulated by IL-1 beta and inhibited by IL-4 and IL-10. J. Immunol. 152, 1354±1361. Guilbert, L. J., Winkler-Lowen, B., Smith, A., Branch, D. R., and Garcia-Lloret, M. (1993). Analysis of the synergistic stimulation of mouse macrophage proliferation by macrophage colony-stimulating factor (CSF-1) and tumor necrosis factor a (TNF-a). J. Leukoc. Biol. 54, 65±72. Hamilton, J. A. (1983). Glucocorticoids and prostaglandins inhibit the induction of macrophage DNA synthesis by macrophage growth factor and phorbol ester. J. Cell. Physiol. 115, 67±74. Hamilton, J. A. (1993). Colony stimulating factors, cytokines and monocyte-macrophages±Some controversies. Immunol. Today 14, 18±24. Haran-Ghera, N., Krautghamer, R., Lapidot, T., Peled, A., Dominguez, M. G., and Stanley, E. R. (1997). Increased circulating colony-stimulating factor-1 (CSF-1) in SJL/J mice with radiation-induced acute myeloid leukemia (AML) is associated with autocrine regulation of AML cells by CSF-1. Blood 89, 2537±2545. Harrington, M. A., Edenberg, H. J., Saxman, S., Pedigo, L. M., Daub, R., and Broxmeyer, H. E. (1991). Cloning and characterization of the murine promoter for the colony-stimulating factor-1-encoding gene. Gene 102, 165±170. Hayashi, M., Numaguchi, M., Watabe, H., and Yaoi, Y. (1996). High blood levels of macrophage colony-stimulating factor in preeclampsia. Blood 88, 4426±4428. Hiraoka, Y., Kishimoto, C., Takada, H., Suzaki, N., and Shiraki, K. (1995). Colony-stimulating factors and coxsackievirus B3 myocarditis in mice: macrophage colony-stimulating factor suppresses acute myocarditis with increasing interferonalpha. Am. Heart J. 130, 1259±1264. Huh, H. Y., Pearce, S. F., Yesner, L. M., Schindler, J. L., and Silverstein, R. L. (1996). Regulated expression of CD36 during monocyte-to-macrophage differentiation: potential role of CD36 in foam cell formation. Blood 87, 2020±2028. Hume, D. A., Pavli, P., Donahue, R. E., and Fidler, I. J. (1988). The effect of human recombinant macrophage colony-stimulating factor (CSF-1) on the murine mononuclear phagocyte system in vivo. J. Immunol. 141, 3405±3409. Itoh, Y., Okanoue, T., Enjyo, F., Sakamoto, S., Ohmoto, Y., Hirai, Y., Kagawa, K., and Kashima, K. (1994). Serum levels of macrophage colony stimulating factor (M-CSF) in liver disease. J. Hepatol. 21, 527±535. Itoh, Y., Okanoue, T., Sakamoto, S., Nishioji, K., and Kashima, K. (1997). The effects of prednisolone and interferons on serum macrophage colony stimulating factor concentrations in chronic hepatitis B. J. Hepatol. 26, 244±252.

930 E. Richard Stanley Itoh, Y., Okanoue, T., Ohnishi, N., Nishioji, K., Sakamoto, S., Nagao, Y., Nakamura, H., Kirishima, T., and Kashima, K. (1999). Hepatic damage induced by transcatheter arterial chemoembolization elevates serum concentrations of macrophagecolony stimulating factor. Liver 19, 97±103. Jacobsen, F. W., Veiby, O. P., and Jacobsen, S. E. (1994). IL-7 stimulates CSF-induced proliferation of murine bone marrow macrophages and Mac-1‡ myeloid progenitors in vitro. J. Immunol. 153, 270±276. Janowska-Wieczorek, A., Belch, A. R., Jacobs, A., Bowen, D., Paietta, E., and Stanley, E. R. (1991). Increased circulating colony-stimulating factor-1 in patients with preleukemia, leukemia, and lymphoid malignancies. Blood 77, 1796±1803. Jimi, E., Shuto, T., and Koga, T. (1995). Macrophage colonystimulating factor and interleukin-1a maintain the survival of osteoclast-like cells. Endocrinology 136, 808±811. Jubinsky, P. T., and Stanley, E. R. (1985). Purification of hemopoietin 1: a multilineage hemopoietic growth factor. Proc. Natl Acad. Sci. USA 82, 2764±2768. Kacinski, B. M. (1995). CSF-1 and its receptor in ovarian, endometrial and breast cancer. Ann. Med. 27, 79±85. Kanzaki, H., Hatayama, H., Narukawa, S., Kariya, M., Fujita, J., and Mori, T. (1995). Hormonal regulation in the production of macrophage colony-stimulating factor and transforming growth factor-beta by human endometrial stromal cells in culture. Horm. Res. 44, 30±35. Kaplan, D. L., Eielson, C. M., Horowitz, M. C., Insogna, K. L., and Weir, E. C. (1996). Tumor necrosis factor-alpha induces transcription of the colony-stimulating factor-1 gene in murine osteoblasts. J. Cell. Physiol. 168, 199±208. Katano, K., Matsumoto, Y., Ogasawara, M., Aoyama, T., Ozaki, Y., Kajiura, S., and Aoki, K. (1997). Low serum MCSF levels are associated with unexplained recurrent abortion. Am. J. Reprod. Immunol. 38, 1±5. Kawasaki, E. S., and Ladner, M. B. (1990). In ``ColonyStimulating Factors. Molecular and Cellular Biology'' (ed T. M. Dexter, J. M. Garland and N. G. Testa), Molecular biology of macrophage colony-stimulating factor pp. 155±176. Marcel Dekker, Inc., New York. Kawasaki, E. S., Ladner, M. B., Wang, A. M., Van Arsdell, J. N., Warren, M. K., Coyne, M. Y., Schweickart, V. L., Lee, M. T., Wilson, K. J., Boosman, A., Stanley, E. R., and Mark, D. F. (1985). Molecular cloning of a complementary DNA encoding human macrophage-specific colony-stimulating factor (CSF-1). Science 230, 291±296. Kimura, F., Takemura, Y., Ohtsuki, T., Mizukami, H., Takagi, S., Yamamoto, K., Nagata, N., and Moyotoshi, K. (1992). Serial changes of the serum macrophage colony-stimulating factor level after cytoreductive chemotherapy. Int. J. Hematol. 55, 147±155. Kodama, H., Yamasaki, A., Abe, M., Niida, S., Hakeda, Y., and Kawashima, H. (1993). Transient recruitment of osteoclasts and expression of their function in osteopetrotic (op/op) mice by a single injection of macrophage colony-stimulating factor. J. Bone Miner. Res. 8, 45±50. Konicek, B. W., Xia, X., Rajavashisth, T., and Harrington, M. A. (1998). Regulation of mouse colony-stimulating factor-1 gene promoter activity by AP1 and cellular nucleic acid-binding protein. DNA Cell Biol. 17, 799±809. Kovacs, C. J., Evans, M. J., Daly, B. M., Thomas-Patterson, D., Johnke, R. M., and Powell, D. S. (1997). Secondary cytokines interact in sequence with interleukin 1alpha (IL-1alpha) with or without macrophage colony-stimulating factor (M-CSF) to further accelerate granulopoietic recovery in myelosuppressed animals. J. Interferon Cytokine Res. 17, 453±460.

Kovacs, C. J., Kerr, J. A., Daly, B. M., Evans, M. J., and Johnke, R. M. (1998). Interleukin 1 alpha (IL-1) and macrophage colony-stimulating factor (M-CSF) accelerate recovery from multiple drug-induced myelosuppression. Anticancer Res. 18, 1805±1812. Krautwald, S., and Baccarini, M. (1993). Bacterially expressed murine CSF-1 possesses agonistic activity in its monomeric form. Biochem. Biophys. Res. Commun. 192, 720±727. Lacey, D. L., Erdmann, J. M., and Tan, H. L. (1994). Interleukin 4 increases type 5 acid phosphatase mRNA expression in murine bone marrow macrophages. J. Cell Biochem. 54, 365±371. Lacey, D. L., Timms, E., Tan, H. L., Kelley, M. J., Dunstan, C. R., Burgess, T., Elliott, R., Colombero, A., Elliott, G., Scully, S., Hsu, H., Sullivan, J., Hawkins, N., Davy, E., Capparelli, C., Eli, A., Qian, Y. X., Kaufman, S., Sarosi, I., Shalhoub, V., Senaldi, G., Guo, J., Delaney, J., and Boyle, W. J. (1998). Osteoprotegerin ligand is a cytokine that regulates osteoclast differentiation and activation. Cell 93, 165±176. Ladner, M. B., Martin, G. A., Noble, J. A., Nikoloff, D. M., Tal, R., Kawasaki, E. S., and White, T. J. (1987). Human CSF-1: gene structure and alternative splicing of mRNA precursors. EMBO J. 6, 2693±2698. Ladner, M. B., Martin, G. A., Noble, J. A., Wittman, V. P., Warren, M. P., McGrogan, M., and Stanley, E. R. (1988). cDNA cloning and expression of murine macrophage colonystimulating factor from L929 cells. Proc. Natl Acad. Sci. USA 85, 6706±6710. Lane, P. W. (1979). Mouse Newsl. 60, 50. Lasek, W., Wankowicz, A., Kuc, K., Feleszko, W., Golab, J., Giermasz, A., Wiktor-Jedrzejczak, W., and JakoÂbisiak, M. (1995). Potentiation of antitumor effects of tumor necrosis factor a and interferon gamma by macrophage-colony-stimulating factor in a MmB16 melanoma model in mice. Cancer Immunol. Immunother. 40, 315±321. Lea, C. K., Sarma, U., and Flanagan, A. M. (1999). Macrophage colony stimulating-factor transcripts are differentially regulated in rat bone-marrow by gender hormones. Endocrinology 140, 273±279. Lees, R. L., and Heersche, J. N. (1999). Macrophage colony stimulating factor increases bone resorption in dispersed osteoclast cultures by increasing osteoclast size. J. Bone Miner. Res. 14, 937±945. Levine, J. A., Jensen, M. D., Eberhardt, N. L., and O'Brien, T. (1998). Adipocyte macrophage colony-stimulating factor is a mediator of adipose tissue growth. J. Clin. Invest. 101, 1557± 1564. Li, H., Schwinzer, R., Baccarini, M., and Lohmann-matthes, M. L. (1989). Cooperative effects of colony-stimulating factor 1 and recombinant interleukin 2 on proliferation and induction of cytotoxicity of macrophage precursors generated from mouse bone marrow cell cultures. J. Exp. Med. 169, 973±986. Liao, F., Berliner, J. A., Mehrabian, M., Navab, M., Demer, L. L., Lusis, A. J., and Fogelman, A. M. (1991). Minimally modified low density lipoprotein is biologically active in vivo in mice [published erratum appears in J. Clin. Invest. 1991; 88, 721]. J. Clin. Invest. 87, 2253±2257. Liao, Z., Caucino, J. A., Schnipper, S. M., Stanley, E. R., Small, C. B., and Rosenstreich, D. L. (1994). Increased urinary cytokine levels in the elderly. Aging: Immunology and Infectious Disease 4, 139±153. McNiece, I. K., Robinson, B. E., and Quesenberry, P. J. (1988). Stimulation of murine colony-forming cells with high proliferative potential by the combination of GM-CSF and CSF-1. Blood 72, 191±195.

CSF-1 Marks Jr., S. C., and Lane, P. W. (1976). Osteopetrosis, a new recessive skeletal mutation on chromosome 12 of the mouse. J. Hered. 67, 11±18. Matsuda, M., Shikata, K., Wada, J., Yamaji, H., Shikata, Y., Doi, A., Kosaka, M., Akagi, H., Masuda, Y., Ohmoto, Y., and Makino, H. (1999). Increased urinary excretion of macrophage-colony-stimulating factor (M-CSF) in patients with IgA nephropathy: tonsil stimulation enhances urinary M-CSF excretion. Nephron 81, 264±270. Matsumura, M., Banba, N., Motohashi, S., and Hattori, Y. (1999). Interleukin-6 and transforming growth factor-beta regulate the expression of monocyte chemoattractant protein-1 and colony-stimulating factors in human thyroid follicular cells. Life Sci. 65, L129±135. Michaelson, M. D., Bieri, P. L., Mehler, M. F., Xu, H., Arezzo, J. C., Pollard, J. W., and Kessler, J. A. (1996). CSF-1 deficiency in mice results in abnormal brain development. Development 122, 2661±2672. Mochizuki, D. Y., Eisenman, J. R., Conlon, P. J., Park, L. S., and Urdal, D. L. (1986). Development and characterization of antiserum to murine granulocyte-macrophage colony-stimulating factor. J. Immunol. 136, 3706±3709. Morohashi, T., Corboz, V. A., Fleisch, H., Cecchini, M. G., and Felix, R. (1994). Macrophage colony-stimulating factor restores bone resorption in op/op bone in vitro in conjunction with parathyroid hormone or 1,25-dihydroxyvitamin D3. J. Bone Miner. Res. 9, 401±407. Motoyoshi, K. (1998). Biological activities and clinical application of M-CSF. Int. J. Hematol. 67, 109±122. Munn, D. H., and Cheung, N. K. (1992). Preclinical and clinical studies of macrophage colony-stimulating factor. Semin. Oncol. 19, 395±407. Munn, D. H., Garnick, M. B., and Cheung, N.-K. V. (1990). Effects of parenteral recombinant human macrophage colonystimulating factor on monocyte number, phenotype, and antitumor cytotoxicity in nonhuman primates. Blood 75, 2042± 2048. Naito, M., Hayashi, S., Yoshida, H., Nishikawa, S., Shultz, L. D., and Takahashi, K. (1991). Abnormal differentiation of tissue macrophage populations in `osteopetrosis' (op) mice defective in the production of macrophage colony-stimulating factor. Am. J. Pathol. 139, 657±667. Nasu, K., Narahara, H., Matsui, N., Kawano, Y., Tanaka, Y., and Miyakawa, I. (1999). Platelet-activating factor stimulates cytokine production by human endometrial stromal cells. Mol. Hum. Reprod. 5, 548±553. Nemunaitis, J. (1998). Use of macrophage colony-stimulating factor in the treatment of fungal infections. Clin. Infect. Dis. 26, 1279±1281. Niida, S., Kaku, M., Amano, H., Yoshida, H., Kataoka, H., Nishikawa, S., Tanne, K., Maeda, N., and Kodama, H. (1999). Vascular endothelial growth factor can substitute for macrophage colony-stimulating factor in the support of osteoclastic bone resorption. J. Exp. Med. 190, 293±298. Nilsson, S. K., and Bertoncello, I. (1994). Age-related changes in extramedullary hematopoiesis in the spleen of normal and perturbed osteopetrotic (op/op) mice. Exp. Hematol. 22, 377±383. Nilsson, S. K., Lieschke, G. J., Garcia-Wijnen, C. C., Williams, B., Tzelepis, D., Hodgson, G., Grail, D., Dunn, A. R., and Bertoncello, I. (1995). Granulocyte-macrophage colonystimulating factor is not responsible for the correction of hematopoietic deficiencies in the maturing op/op mouse. Blood 86, 66±72. Ohno, R. (1998). Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor and macrophage

931

colony-stimulating factor in the treatment of acute myeloid leukemia and acute lymphoblastic leukemia. Leuk. Res. 22, 1143±1154. Ohno, R., Miyawaki, S., Hatake, K., Kuriyama, K., Saito, K., Kanamaru, A., Kobayashi, T., Kodera, Y., Nishikawa, K., Matsuda, S., Yamada, O., Omoto, E., Takeyama, H., Tsukuda, K., Asou, N., Tanimoto, M., Shiozaki, H., Tomonaga, M., Masaoka, T., Miura, Y., Takaku, F., Ohashi, Y., and Motoyoshi, K. (1997). Human urinary macrophage colony-stimulating factor reduces the incidence and duration of febrile neutropenia and shortens the period required to finish three courses of intensive consolidation therapy in acute myeloid leukemia: a double-blind controlled study. J. Clin. Oncol. 15, 2954±2965. Pai, R., Kirschenbaum, M. A., and Kamanna, V. S. (1995). Lowdensity lipoprotein stimulates the expression of macrophage colony-stimulating factor in glomerular mesangial cells. Kidney Int. 48, 1254±1262. Pampfer, S., Tabibzadeh, S., Chuan, F.-C., and Pollard, J. W. (1991). Expression of colony-stimulating factor-1 (CSF-1) messenger RNA in human endometrial glands during the menstrual cycle: Molecular cloning of a novel transcript that predicts a cell surface form of CSF-1. Mol. Endocrinol. 5, 1931±1938. Pandit, J., Bohm, A., Jancarik, J., Halenbeck, R., Koths, K., and Kim, S.-H. (1992). Three-dimensional structure of dimeric human recombinant macrophage colony-stimulating factor. Science 258, 1358±1362. Partenheimer, A., Schwarz, K., Wrocklage, C., Kolsch, E., and Kresse, H. (1995). Proteoglycan form of colony-stimulating factor-1 (proteoglycan-100). Stimulation of activity by glycosaminoglycan removal and proteolytic processing. J. Immunol. 155, 5557±5565. Peng, H. B., Rajavashisth, T. B., Libby, P., and Liao, J. K. (1995). Nitric oxide inhibits macrophage-colony stimulating factor gene transcription in vascular endothelial cells. J. Biol. Chem. 270, 17050±17055. Petros, W. P., Rabinowitz, J., Stuart, A. R., Gupton, C., Alderman, E. M., and Peters, W. P. (1994). Elevated endogenous serum macrophage colony-stimulating factor in the early stage of fungemia following bone marrow transplantation. Exp. Hematol. 22, 582±586. Pollard, J. W., and Hennighausen, L. (1994). Colony stimulating factor 1 is required for mammary gland development during pregnancy. Proc. Natl Acad. Sci. USA 91, 9312±9316. Pollard, J. W., and Stanley, E. R. (1996). Pleiotropic roles for CSF-1 in development defined by the mouse mutation osteopetrotic (op). Adv. Dev. Biochem. 4, 153±193. Pollard, J. W., Bartocci, A., Arceci, R., Orlofsky, A., Ladner, M. B., and Stanley, E. R. (1987). Apparent role of the macrophage growth factor, CSF-1, in placental development. Nature 330, 484±486. Pollard, J. W., Hunt, J. W., Wiktor-Jedrzejczak, W., and Stanley, E. R. (1991). A pregnancy defect in the osteopetrotic (op/op) mouse demonstrates the requirement for CSF-1 in female fertility. Dev. Biol. 148, 273±283. Pollard, J. W., Dominguez, M. G., Mocci, S., Cohen, P. E., and Stanley, E. R. (1997). Effect of the colony-stimulating factor-1 null mutation, osteopetrotic (csfm(op)), on the distribution of macrophages in the male mouse reproductive tract. Biol. Reprod. 56, 1290±1300. Price, L. K. H., Choi, H. U., Rosenberg, L., and Stanley, E. R. (1992). The predominant form of secreted colony stimulating factor-1 is a proteoglycan. J. Biol. Chem. 267, 2190±2199. Qiao, J. H., Tripathi, J., Mishra, N. K., Cai, Y., Tripathi, S., Wang, X. P., Imes, S., Fishbein, M. C., Clinton, S. K.,

932 E. Richard Stanley Libby, P., Lusis, A. J., and Rajavashisth, T. B. (1997). Role of macrophage colony-stimulating factor in atherosclerosis: studies of osteopetrotic mice. Am. J. Pathol. 150, 1687±1699. Rabinowitz, J., Petros, W. P., Stuart, A. R., and Peters, W. P. (1993). Characterization of endogenous cytokine concentrations after high-dose chemotherapy with autologous bone marrow support. Blood 81, 2452±2459. Raivich, G., Moreno-Flores, M. T., Moller, J. C., and Kreutzberg, G. W. (1994). Inhibition of posttraumatic microglial proliferation in a genetic model of macrophage colonystimulating factor deficiency in the mouse. Eur. J. Neurosci. 6, 1615±1618. Rajavashisth, T., Qiao, J. H., Tripathi, S., Tripathi, J., Mishra, N., Hua, M., Wang, X. P., Loussararian, A., Clinton, S., Libby, P., and Lusis, A. (1998). Heterozygous osteopetrotic (op) mutation reduces atherosclerosis in LDL receptor-deficient mice. J. Clin. Invest. 101, 2702±2710. Rajavashisth, T. B., Eng, R., Shadduck, R. K., Waheed, A., BenAvram, C. M., Shively, J. E. A., and Lusis, A. J. (1987). Cloning and tissue-specific expression of mouse macrophage colonystimulating factor mRNA. Proc. Natl Acad. Sci. USA 84, 1157±1161. Rajavashisth, T. B., Andalibi, A., Territo, M. C., Berliner, J. A., Navab, M., Fogelman, A. M., and Lusis, A. J. (1990). Induction of endothelial cell expression of granulocyte and macrophage colony-stimulating factors by modified low-density lipoproteins. Nature 344, 254±257. Rajavashisth, T. B., Yamada, H., and Mishra, N. K. (1995). Transcriptional activation of the macrophage-colony stimulating factor gene by minimally modified LDL ± Involvement of nuclear factor-kappaB. Arterioscler. Thromb. Vasc. Biol. 15, 1591±1598. Ralph, P., and Sampson-Johannes, A. (1990). Macrophage growth and stimulating factor, M-CSF. Prog. Clin. Biol. Res. 338, 43±64. Ralph, P., Warren, M. K., Nakoinz, I., Lee, M. T., Brindley, L., Sampson Johannes, A., Kawasaki, E. S., Ladner, M. B., Strickler, J. E., Boosman, A., Csejtey, J., and White, T. J. (1986). Biological properties and molecular biology of the human macrophage growth factor, CSF-1. Immunobiology 172, 194±204. Regenstreif, L. J., and Rossant, J. (1989). Expression of the c-fms proto-oncogene and of the cytokine, CSF-1, during mouse embryogenesis. Dev. Biol. 133, 284±294. Rettenmier, C. W., Roussel, M. F., Ashmun, R. A., Ralph, P., Price, K., and Sherr, C. J. (1987). Synthesis of membrane-bound colony-stimulating factor 1 (CSF-1) and downmodulation of CSF-1 receptors in NIH 3T3 cells transformed by cotransfection of the human CSF-1 and c-fms (CSF-1 receptor) genes. Mol. Cell. Biol. 7, 2378±2387. Roth, P., and Stanley, E. R. (1992). The biology of CSF-1 and its receptor. Curr. Top. Microbiol. Immunol. 181, 141±167. Roth, P., Bartocci, A., and Stanley, E. R. (1997). Lipopolysaccharide induces synthesis of mouse colony-stimulating factor-1 in vivo. J. Immunol. 158, 3874±3880. Roth, P., Dominguez, M. G., and Stanley, E. R. (1998). The effects of CSF-1 on the distribution of mononuclear phagocytes in the developing osteopetrotic mouse. Blood 91, 3773±3783. Roy, S., Sedqi, M., Ramakrishnan, S., Barke, R. A., and Loh, H. H. (1996). Differential effects of opioids on the proliferation of a macrophage cell line, Bac 1.2F5. Cell. Immunol. 169, 271±277. Rubin, J., Fan, X., Thornton, D., Bryant, R., and Biskobing, D. (1996). Regulation of murine osteoblast macrophage

colony-stimulating factor production by 1,25(OH)2D3. Calcif. Tissue Int. 59, 291±296. Rubin, J., Biskobing, D. M., Jadhav, L., Fan, D., Nanes, M. S., Perkins, S., and Fan, X. (1998). Dexamethasone promotes expression of membrane-bound macrophage colony-stimulating factor in murine osteoblast-like cells. Endocrinology 139, 1006± 1012. Rysava, R., Merta, M., Tesar, V., Jirsa, M., and Zima, T. (1999). Can serum amyloid A or macrophage colony stimulating factor serve as marker of amyloid formation process? Biochem. Mol. Biol. Int. 47, 845±850. Sanda, M. G., Bolton, E., Mule, J. J., and Rosenberg, S. A. (1992). In vivo administration of recombinant macrophage colony-stimulating factor induces macrophage-mediated antibody-dependent cytotoxicity of tumor cells. J. Immunother. 12, 132±137. Sanford, T. R., De, M., and Wood, G. W. (1992). Expression of colony-stimulating factors and inflammatory cytokines in the uterus of CD1 mice during Days 1 to 3 of pregnancy. J. Reprod. Fertil. 94, 213±220. Sapi, E., and Kacinski, B. M. (1999). The role of CSF-1 in normal and neoplastic breast physiology. Proc. Soc. Exp. Biol. Med. 220, 1±8. Sasaki, K., Hirata, K., Torimoto, K., Sakawaki, T., Nakamura, M., Sato, N., and Kikuchi, K. (1995). Macrophage colony stimulating factor inhibits experimental liver metastases from colon cancer. Anticancer Res. 15, 1235±1239. Scholl, S. M., Lidereau, R., de la Rochefordiere, A., Le-Nir, C. C., Mosseri, V., Nogues, C., Pouillart, P., and Stanley, F. R. (1996). Circulating levels of the macrophage colony stimulating factor CSF-1 in primary and metastatic breast cancer patients. A pilot study. Breast Cancer Res. Treat. 39, 275±283. Sherr, C. J., Rettenmier, C. W., Sacca, R., Roussel, M. F., Look, A. T., and Stanley, E. R. (1985). The c-fms proto-oncogene product is related to the receptor for the mononuclear phagocyte growth factor, CSF-1. Cell 41, 665±676. Shimano, H., Yamada, N., Ishibashi, S., Harada, K., Matsumoto, A., Mori, N., Inaba, T., Motoyoshi, K., Itakura, H., and Takaku, F. (1990). Human monocyte colony-stimulating factor enhances the clearance of lipoproteins containing apolipoprotein B-100 via both low density lipoprotein receptor-dependent and -independent pathways in rabbits. J. Biol. Chem. 265, 12869±12875. Shirono, K., and Tsuda, H. (1995). Virus-associated haemophagocytic syndrome in previously healthy adults. Eur. J. Haematol. 55, 240±244. Sone, S., Tsuruo, T., Sato, S., Yano, S., Nishioka, Y., and Shinohara, T. (1996). Transduction of the macrophage colony-stimulating factor gene into human multidrug resistant cancer cells: enhanced therapeutic efficacy of monoclonal antiP-glycoprotein antibody in nude mice. Jpn J. Cancer Res. 87, 757±764. Srivastava, S., Weitzmann, M. N., Kimble, R. B., Rizzo, M., Zahner, M., Milbrandt, J., Ross, F. P., and Pacifici, R. (1998). Estrogen blocks M-CSF gene expression and osteoclast formation by regulating phosphorylation of Egr-1 and its interaction with Sp-1. J. Clin. Invest. 102, 1850±1859. Stanley, E. R. (1979). Colony-stimulating factor (CSF) radioimmunoassay: detection of a CSF subclass stimulating macrophage production. Proc. Natl Acad. Sci. USA 76, 2969±2973. Stanley, E. R. (1981). In ``The Lymphokines'' (ed W.E. Stewart and J.W. Hadden), Colony stimulating factors pp. 102±132. Humana Press, New Jersey. Stanley, E. R. (1985). The macrophage colony-stimulating factor, CSF-1. Methods Enzymol. 116, 564±587.

CSF-1 Stanley, E. R. (1994). In ``The Cytokine Handbook'' (ed A.W. Thomson), Colony stimulating factor-1 (macrophage colony stimulating factor) pp. 387±418. Academic Press, San Diego. Stanley, E. R. (1998). In ``Encyclopedia of Immunology'' (ed P.J. Delves and I.M.Roitt), Macrophage colony stimulating factor CSF-1 pp. 1650±1654. Academic Press, Orlando. Stanley, E. R., and Heard, P. M. (1977). Factors regulating macrophage production and growth conditioned by mouse L cells. J. Biol. Chem. 252, 4305±4312. Stanley, E. R., Chen, D. M., and Lin, H.-S. (1978). Induction of macrophage production and proliferation by a purified colony stimulating factor. Nature 274, 168±170. Stanley, E. R., Guilbert, L. J., Tushinski, R. J., and Bartelmez, S. H. (1983). CSF-1 ± a mononuclear phagocyte lineage-specific hemopoietic growth factor. J. Cell. Biochem. 21, 151±159. Stanley, E. R., Bartocci, A., Patinkin, D., Rosendaal, M., and Bradley, T. R. (1986). Regulation of very primitive multipotent hematopoietic cells by hemopoietin-1. Cell 45, 667±674. Stein, J., and Rettenmier, C. W. (1991). Proteolytic processing of a plasma membrane-bound precursor to human macrophage colony-stimulating factor (CSF-1) is accelerated by phorbol ester. Oncogene 6, 601±605. Stein, J., Borzillo, G. V., and Rettenmier, C. W. (1990). Direct stimulation of cells expressing receptors for macrophage colonystimulating factor (CSF-1) by a plasma membrane-bound precursor of human CSF-1. Blood 76, 1308±1314. Stoudemire, J. B., and Garnick, M. B. (1991). Effects of recombinant human macrophage colony-stimulating factor on plasma cholesterol levels. Blood 77, 750±755. Suehiro, A., Tsujioka, H., Yoshimoto, H., Higasa, S., and Kakishita, E. (1999). Serum macrophage colony-stimulating factor (M-CSF) level is elevated in patients with old cerebral infarction related to vascular damage. Am. J. Hematol. 60, 185± 190. Suzu, S., Ohtsuki, T., Makishima, M., Yanai, N., Kawashima, T., Nagata, N., and Motoyoshi, K. (1992). Biological activity of a proteoglycan form of macrophage colony-stimulating factor and its binding to type V collagen. J. Biol. Chem. 267, 16812± 16815. Suzu, S., Ohtsuki, T., Yanai, N., Takatsu, Z., Kawashima, T., Takaku, F., Nagata, N., and Motoyoshi, K. (1992). Identification of a high molecular weight macrophage colonystimulating factor as a glycosaminoglycan-containing species. J. Biol. Chem. 267, 4345±4348. Suzu, S., Kimura, F., Ota, J., Motoyoshi, K., Itoh, T., Mishima, Y., Yamada, M., and Shimamura, S. (1997). Biologic activity of proteoglycan macrophage colony-stimulating factor. J. Immunol. 159, 1860±1867. Takahashi, K., Naito, M., and Shultz, L. D. (1992). Differentiation of epidermal Langerhans cells in macrophage colony-stimulating-factor-deficient mice homozygous for the osteopetrosis (op) mutation. J. Invest. Dermatol. 99, 46S±47S. Takahashi, K., Naito, M., Shultz, L. D., Hayashi, S., and Nishikawa, S. (1993). Differentiation of dendritic cell populations in macrophage colony-stimulating factor-deficient mice homozygous for the osteopetrosis (op) mutation. J. Leukoc. Biol. 53, 19±28. Takahashi, M., Hirato, T., Takano, M., Nishida, T., Nagamura, K., Kamogashira, T., Nakai, S., and Hirai, Y. (1989). Amino-terminal region of human macrophage colony-stimulating factor (M-CSF) is sufficient for its in vitro biological activity: Molecular cloning and expression of carboxyl-terminal deletion mutants of human M-CSF. Biochem. Biophys. Res. Commun. 161, 892±901.

933

Takamatsu, S., and Nakano, K. (1998). Regulation of interleukin6, and macrophage colony-stimulating factor mRNA levels by histamine in stromal cell line (MC3T3-G2/PA6). Inflamm. Res. 47, 221±226. Takatsuka, H., Umezu, H., Hasegawa, G., Usuda, H., Ebe, Y., Naito, M., and Shultz, L. D. (1998). Bone remodeling and macrophage differentiation in osteopetrosis (op) mutant mice defective in the production of macrophage colony-stimulating factor. J. Submicrosc. Cytol. Pathol. 30, 239±247. Takeda, S., Soutter, W. P., Dibb, N. J., and White, J. O. (1996). Biological activity of the receptor for macrophage colonystimulating factor in the human endometrial cancer cell line, Ishikawa. Br. J. Cancer 73, 615±619. Tashiro, H., Shimokawa, H., Yamamoto, K., Momohara, M., Tada, H., and Takeshita, A. (1997). Altered plasma levels of cytokines in patients with ischemic heart disease. Coron. Artery Dis. 8, 143±147. Teicher, B. A., Ara, G., Menon, K., and Schaub, R. G. (1996). In vivo studies with interleukin-12 alone and in combination with monocyte colony-stimulating factor and/or fractionated radiation treatment. Int. J. Cancer 65, 80±84. Utsunomiya, K., Ohta, H., Kurata, H., Tajima, N., and Isogai, Y. (1995). The effect of macrophage colony-stimulating factor (M-CSF) on the progression of lipid-induced nephrotoxicity in diabetic nephropathy. J. Diabetes Complications 9, 292±295. Vairo, G., Argyriou, S., Knight, K. R., and Hamilton, J. A. (1991). Inhibition of colony-stimulating factor-stimulated macrophage proliferation by tumor necrosis factor-a, IFNgamma, and lipopolysaccharide is not due to a general loss of responsiveness to growth factor. J. Immunol. 146, 3469±3477. Vallera, D. A., Taylor, P. A., Aukerman, S. L., and Blazar, B. R. (1993). Antitumor protection from the murine T-cell leukemia/ lymphoma EL4 by the continuous subcutaneous coadministration of recombinant macrophage-colony stimulating factor and interleukin-2. Cancer Res. 53, 4273±4280. Vial, T., and Descotes, J. (1995). Clinical toxicity of cytokines used as haemopoietic growth factors. Drug Safety 13, 371±406. Webb, S. E., Pollard, J. W., and Jones, G. E. (1996). Direct observation and quantification of macrophage chemoattraction to the growth factor CSF-1. J. Cell Sci. 109, 793±803. Wegiel, J., Wisniewski, H. M., Dziewiatkowski, J., Tarnawski, M., Kozielski, R., Trenkner, E., and Wiktor-Jedrzejczak, W. (1998). Reduced number and altered morphology of microglial cells in colony stimulating factor-1-deficient osteopetrotic op/op mice. Brain Res. 804, 135±139. Weir, E. C., Horowitz, M. C., Baron, R., Centrella, M., Kacinski, B. M., and Insogna, K. L. (1993). Macrophage colony-stimulating factor release and receptor expression in bone cells. J. Bone Miner. Res. 8, 1507±1518. Wiener, E., Wanachiwanawin, W., Chinprasertsuk, S., Siripanyaphinyo, U., Mawas, F., Fucharoen, S., and Wickramasinghe, S. N. (1996). Increased serum levels of macrophage colony-stimulating factor (M-CSF) in alpha- and beta-thalassaemia syndromes: correlation with anaemia and monocyte activation. Eur. J. Haematol. 57, 364±369. Wiktor-Jedrzejczak, W., and Gordon, S. (1996). Cytokine regulation of the macrophage (M phi) system studied using the colony stimulating factor-1-deficient op/op mouse. Physiol. Rev. 76, 927±947. Wiktor-Jedrzejczak, W., Ahmed, A., Szczylik, C., and Skelly, R. R. (1982). Hematological characterization of congenital osteopetrosis in op/op mouse. J. Exp. Med. 156, 1516±1527. Wiktor-Jedrzejczak, W., Bartocci, A., Ferrante, A. W., AhmedAnsari, A., Sell, K. W., Pollard, J. W., and Stanley, E. R. (1990). Total absence of colony-stimulating factor 1 in the

934 E. Richard Stanley macrophage-deficient osteopetrotic (op/op) mouse. Proc. Natl Acad. Sci. USA 87, 4828±4832. Wiktor-Jedrzejczak, W., Urbanowska, E., Aukerman, S. L., Pollard, J. W., Stanley, E. R., Ralph, P., Ansari, A. A., Sell, K. W., and Szperl, M. (1991). Correction by CSF-1 of defects in the osteopetrotic op/op mouse suggests local, developmental, and humoral requirements for this growth factor. Exp. Hematol. 19, 1049±1054. Wiktor-Jedrzejczak, W., Ansari, A. A., Szperl, M., and Urbanowska, E. (1992). Distinct in vivo functions of two macrophage subpopulations as evidenced by studies using macrophage-deficient op/op mouse. Eur. J. Immunol. 22, 1951±1954. Wilkins, J. A., Cone, J., Randhawa, Z. I., Wood, D., Warren, M. K., and Witkowska, H. E. (1993). A study of intermediates involved in the folding pathway for recombinant human macrophage colony-stimulating factor (M-CSF): Evidence for two distinct folding pathways. Protein Sci. 2, 244±254. Williams, N. (1979). Preferential inhibition of murine macrophage colony formation by prostaglandin E. Blood 53, 1089±1094. Williams, N., Bertoncello, I., Kavnoudias, H., Zsebo, K., and McNiece, I. (1992). Recombinant rat stem cell factor stimulates the amplification and differentiation of fractionated mouse stem cell populations. Blood 79, 58±64. Witmer-Pack, M. D., Hughes, D. A., Schuler, G., Lawson, L., McWilliam, A., Inaba, K., Steinman, R. M., and Gordon, S. (1993). Identification of macrophages and dendritic cells in the osteopetrotic (op/op) mouse. J. Cell Sci. 104, 1021±1029. Wong, G. G., Temple, P. A., Leary, A. C., Witek Giannotti, J. S., Yang, Y. C., Ciarletta, A. B., Chung, M., Murtha, P., Kriz, R., Kaufman, R. J., Ferenz, C. R., Sibley, B. S., Turner, K. J., Hewick, R. M., Clark, S. C., Yanai, N., Yokota, H., Yamada, M., Saito, M., Motoyoshi, K., and Takaku, F. (1987). Human CSF-1: molecular cloning and expression of 4-kb cDNA encoding the human urinary protein. Science 235, 1504±1508. Yano, S., Hanibuchi, M., Nishioka, Y., Nokihara, H., Nishimura, N., Tsuruo, T., and Sone, S. (1999). Combined therapy with anti-P-glycoprotein antibody and macrophage colony-stimulating factor gene transduction for multiorgan metastases of multidrug-resistant human small cell lung cancer in NK cell-depleted SCID mice. Int. J. Cancer 82, 105±111.

Yasuda, H., Shima, N., Nakagawa, N., Yamaguchi, K., Kinosaki, M., Mochizuki, S., Tomoyasu, A., Yano, K., Goto, M., Murakami, A., Tsuda, E., Morinaga, T., Higashio, K., Udagawa, N., Takahashi, N., and Suda, T. (1998). Osteoclast differentiation factor is a ligand for osteoprotegerin/osteoclastogenesis-inhibitory factor and is identical to TRANCE/RANKL. Proc. Natl Acad. Sci. USA 95, 3597±3602. Yoshida, H., Hayashi, S.-I., Kunisada, T., Ogawa, M., Nishikawa, S., Okamura, H., Sudo, T., Shultz, L. D., and Nishikawa, S.-I. (1990). The murine mutation ``osteopetrosis'' (op) is a mutation in the coding region of the macrophage colony stimulating factor (Csfm) gene. Nature 345, 442±444. Yoshihara, K., Inumaru, S., Hirota, Y., and Momotani, E. (1998). Cloning and sequencing of cDNA encoding bovine macrophage colony-stimulating factor (bM-CSF) and expression of recombinant bM-CSF using baculovirus. Vet. Immunol. Immunopathol. 63, 381±391. Yoshioka, H., Hama, S., Sadatomo, T., Taniguchi, E., Harada, K., Sugiyama, K., Kimura, F., Motoyoshi, K., and Kurisu, K. (1998). Transformation of rat glioma cells with the M-CSF gene inhibits tumorigenesis in vivo. J. Neurooncol. 40, 197±204.

LICENSED PRODUCTS See Table 4.

ACKNOWLEDGEMENTS This work was supported by National Institutes of Health (NIH) grants CA 26504, CA 32551, and the Albert Einstein Cancer Center Grant P30-13330. I thank Dr Y.-G. Yeung and Elyse Rizzo for help in the preparation of the manuscript.

Table 4 Sources of CSF-1 and CSF-1 antibodies Product

Description

Supplier

Human CSF-1

Recombinant human M-CSF

Peprotech (http://www.peprotech.com

Human CSF-1

Recombinant human M-CSF

Sigma Corp. (http://www.sigma.sial.com)

Mouse CSF-1

Recombinant mouse M-CSF

Sigma Corp. (http://www.sigma.sial.com)

Anti-human CSF-1 antiserum Rabbit anti-recombinant human

Peprotech (http://www.peprotech.com)

M-CSF Anti-mouse CSF-1 antibody

Rabbit anti-recombinant human

Sigma Corp. (http://www.sigma.sial.com)

M-CSF Anti-mouse CSF-1 antibody

Rat anti-mouse CSF-1 monoclonal Calbiochem (http://www.calbiochem.com) antibody recognizes human and mouse CSF-1