M-CSF

Macrophage CSF, which stimulates the proliferation and differentiation of monocytes, is produced by macrophages, endothelial cells and fibroblasts. It is a homodimer glycoprotein of relative molecular mass 40-80 kDa. Its production by macrophages is stimulated by the addition of IL-3, GM-CSF and 

The biologically active form of M-CSF is a homodimer. These homodimers can exist as integral cell surface proteins, or may be released from their producer cell by proteolytic cleavage, thus yielding the soluble cytokine. 

The M-CSF receptor is a single chain, heavily glycosylated, polypeptide of molecular mass 150 kDa. Its intracellular domain displays tyrosine kinase activity which is capable of autophosphorylation, as well as phosphorylating additional cytoplasmic polypeptides. 

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GM-CSF, G-CSF, M-CSF, multi-CSF cytotoxic injury bone marrow transplantation myelodysplastic syndromes AIDS neutropenia rodent and human... 

Interleukin-1 OC and (3. IL-1 has radioprotective activity toward BM and other tissues (151,164). IL-1 is produced in response to endotoxin, other cytokines, and microbial and viral agents, primarily by monocytes and macrophages. Other nucleated cells can also produce it. IL-1 appears to play an important role in the regulation of normal hemopoiesis directly by stimulating the most primitive stem cells and indirectly by stimulating other hemopoietic factors, including G-CSF, GM-CSF, M-CSF, and IL-6. 

Cytokines and biological response modifiers represent a broad class of therapeutic agents that modify the hosts response to cancer or cancer therapies. The enormous body information about their clinical uses and their side effects is beyond the scope of this essay that can only give illustrative examples. For an up-to-date information the reader can resort to reference [5]. As many as 33 different interleukins are known and the list continues to grow IL-2 used in the treatment of kidney cancer is one example. Interferon alpha is used for chronic myelogenous leukeia, hairy cell leukaemia and Kaposi s sarcoma. Interferons are also used in the treatment of chronic infections such as viral hepatitis. Tumor necrosis factor (alpha), G/GM/M-CSF, and several other cellular factors are used in treatment of various cancers. Many of these cytokines produce serious side effects that limit their use. 

Fig. 2.1 Sequence of events in atherogenesis and role of low-density lipoprotein. Native LDL, in the subendothelial space, undergoes progressive oxidation (mmLDL) and activates the expression of MCP-1 and M-CSF in the endothelium (EC). MCP-1 and M-CSF promote the entry and maturation of monocytes to macrophages, which further oxidise LDL (oxLDL). Ox-LDL is specifically recognised by the scavenger receptor of macrophages and, once internalised, formation of foam cells occurs. Both mmLDL and oxLDL induce endothelial dysfunction, associated with changes of the adhesiveness to leukoc)des or platelets and to wall permeability.

Sustained NF-kB activation, TNF-a, IL-1, proliferation, signals (M-CSF, G-CSF), chemotaxis (MCP-1), adhesion (VCAM-1, ICAM-1), thrombogenesis (TF)... 

IkB inhibitory protein kappa B lCAM-1 intercellular adhesion molecule 1 lL-1 interleukin-1 LDL low density lipoprotein MAPKs mitogen activated protein kinases MCP-1 macrophage chemotactic protein 1 M-CSF macrophage colony stimulating factor mmLDL minimally modified LDL NAC A-acetylcysteine NF-kB nuclear factor-kappa B oxLDL oxidised LDL PKC protein kinase C PMA phobol myristate acetate ROS reactive oxygen species TNF-a tumour necrosis factor alpha AM-1 vascular cell adhesion molecule 1... 

FRUEBis J, GONZALEZ v, siLVESTRE M and PALiNSKi w (1997) Effect of probucol treatment on gene expression of VCAM-1, MCP-1, and M-CSF in the aortic wall of LDL receptor-deficient rabbits during early sihsro genss.is, Arteriosclerosis, Thrombosis and Vascular Biology 17, 1289-302. 

M-CSF Monocyte/macrophage colony-stimulating factor MCt Tryptase-containing mast cell MCtc Tryptase- and chymase-containing mast cell MDA Malondialdehyde MDGF Macrophage-derived growth factor... 

M-CSF serves as a growth, differentiation and activation factor for macrophages and their precursor cells. It is also known as CSF-1. This cytokine is produced by various cell types (Table 10.5). The mature form is a glycoprotein containing three potential N-linked glycosylation sites. Three related forms of human M-CSF have been characterized. All are ultimately... 

The proposed model to explain OCS is schematized in Fig. 7.2. Several agents, induced or not for estrogen deficiency, stimulate the expression of RANKL on stromal/OB cells. The binding of RANKL with its receptor RANK on osteoclastic precursors, together with M-CSF, is a necessary and sufficient condition to carry out all the steps in the formation and differentiation of the osteoclasts. Undoubtedly all this is much more complex than what is described here since at least 24 genes that positively and negatively regulate OCS have been described (Boyle et al. 2003). 

Fig. 7.3. Osteoclastogenesis after estrogen deficiency. Estrogen deprivation leads to an increase in the synthesis of RANKL for stromal/OB cells of the BM. This increase in the expression of RANKL leads to an increase in OCS. Estrogen deficiency also induces the synthesis and secretion of cytokines, such as IL-6 and M-CSF, that increase the number of preosteoclasts in the BM, and thus increases OCS. Nonetheless, certain cells of the immune system, such as monocytes and T-cells, intervene in the process when the supply of estrogens fails. These cells secrete IL-1 and TNF-a that are powerful inductors of OCS. When estrogens or agonists of estrogen receptors like raloxifene are administered, the synthesis and secretion of many of the mentioned cytokines diminish and the synthesis and liberation of OPG and TGF-/S are stimulated. These molecules inhibit OCS by inhibiting the RANKL/RANK signal pathway and by promoting osteoclast apoptosis...

If the RANKL/OPG system is a final effector on the biology of osteoclasts, then this system should be the basis for the antiresorptive effects of estrogen. Indeed, estrogen stimulates OPG synthesis for osteoblastic cells (Hofbauer et al. 1999), estrogen deficiency induced by OVX results in a decrease in OPG and increased RANKL production, an action that is prevented by estradiol administration, and OPG administration prevents bone loss induced by OVX (Simonet et al. 1997 Hofbauer et al. 2000 Hofbauer 1999). In addition, estrogen can suppress RANKL and M-CSF-induced differentiation of myelomonocytic precursors into multinucleated TRAP+ osteoclasts through an ER-dependent mechanism that does not require mediation by stromal cells (Shevde et al. 2000). Finally, treatment with estradiol inhibits the response of osteoclast precursors to the action of RANKL (Srivastava et al. 2001). 

Interleukins (IL-l-IL-13 have now been characterised) colony-stimulating factors (CSFs), such as granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF) and macrophage CSF (M-CSF) ... 

M-CSF CSF-1 70-90 (dimer) 21 (subunit) monocytes lpl3-21 macrophages, fibroblasts, endothelial cells... 

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