Effect of M-CSF on Bone Resorption

Korean J Bone Metab > Volume 16(1); 2009 > Article

Original Article

Korean Journal of Bone Metabolism 2009;16(1):15-21.

Effect of M-CSF on Bone Resorption

골 흡수에 M-CSF의 효과

오성렬,박성태,이명수,김헌수1,곽한복2

원광대학교 의과대학 내과학교실, 병리학교실1, 해부학교실2

Abstract

Objective
Osteoclasts are multinucleated cells of the monocyte-macrophage lineage that are responsible for the resorption of bone. Macrophage-colony stimulating factor (M-CSF) plays an important role in osteoclast differentiation and survival. However, the effect of M-CSF in bone resorption remains unknown.
Methods
Mature osteoclasts were prepared by cocultures of bone marrow cells and calvarial osteoblasts. Osteoclasts were stained with rhodamine-conjugated phalloidin to visualize F-actin. To determine resorption activity, osteoclasts were incubated on hydroxyapatite-coated 48-well plate. M-CSF signaling was analyzed by Western blotting.
Results
M-CSF significantly induced the survival of osteoclasts. Actin ring formation was induced by M-CSF. M-CSF did not induce bone resorption. Although, M-CSF greatly induced the phosphorylation of Akt and ERK, M-CSF did not induce I-κB degradation.
Conclusions
Our findings suggest that M-CSF significantly promoted osteoclast survival. However, M-CSF did not regulate bone resorption. These results suggest that enhanced osteoclast survival is necessary but not sufficient to induce bone resorption. [Korean Journal of Bone Metabolism, 16(1): 15-21, 2009]

Key Words: Osteoclast, M-CSF, Survival, Resorption