Osteocyte가 파골세포전구세포 모집에 미치는 영향

Abstract

The mechanisrn whereby osteoclasts are attracted to s야cific areas of bone for 잉rgeted rernoval is unknown. It has been hypothesized that the osteocytes, whether unstrained as in irnmobilization or overstr잉ned as in pathological overload, can send signals indicating which bone shouId be rernoved. Therefore, we eXaIIÙn외 the effect of osteocytes on recruitrnent of osteoclast precursors. MLO-Y 4 cells were used as a rnodel for osteocytes and RA W264.7 cells were used as rnode1s for osteoclast precursors W江0-Y 4 cells condition어 m때ium (MLO-Y 4 CM) was COllected 따ter 24h cuIture. The rnigration of RA W264.7 was assayed using σ밍lswell rnernbranes (polycarbonate, 8 씨n pores) with control rn때ia or 10, 20, 50, 100% MLO-Y4 CM. MLO-Y4 CM alone increased transrnigration of RA W264.7 cells. According to gene aπayan떠ysis of MLO-Y 4, it has been shown that 5 factors e1evated in MLO-Y 4 cells cornpared to 2T3 ostecblasts, that had previously been described as chernotaxis factors. Two chernokines, MCP-3 and MlP-2 have been described to be chernotactic for monocytes and neutrophils, but their effect on osteoclast precursors was not known‘ TGF-ßl, VEGF and M-CSF are known to induce osteoclast chemotaxis. To deterrnine the factor(s) responsible, we exaIIÙned the effect of these factors on RA W264.7 cell migration and did the blocking assay with antibodies to these factors. MCP-3, TGF-ßl and M-CSF increased transrnigration of RAW:쟁4.7 cells, whereas VEGF and MlP-2 had no effect. Anti-MCP-3 antibody and anti-TGF-ß antibody couId not block the MLO-Y4 CM induced RAW264.7 cell rnigration. Anti-M-CSF antibody could block the MLO-Y 4 CM induced RA W264.7 cell rnigration but not cornpletely‘ These results suggest that osteocytes can i띠tiate the bone resorption by recruitment of.osteoclast precursors.