[Effect of adiponectin on human osteoblast differentiation].
OBJECTIVE
To investigate the effect of adiponectin on the osteoblast differentiation and its signal transduction.


METHODS
Adipopnectin receptor (AdipoR) was detected by immunoblot analysis. Alkaline phosphatase (ALP) activity was measured by enzyme-linked immunosorbent assay. Osteocalcin was measured by a specific radioimmunoassay kit, and the extent of mineralized matrix was determined. RNA interference was used to down-regulate the expression of AdipoR1 in human osteoblasts, and the effect of adiponectin on osteoblast differentiation was investigated.


RESULTS
Only AdipoR1 protein was detected in human osteoblasts. Adiponectin could promote osteoblast differentiation, and result in a dose-dependent increase in ALP activity, osteocalcin secretion, and an increase in mineralized nodules. Suppression of AdipoR1 with siRNA could abolish the adiponectin induced ALP expression. Adiponectin could induce the activation of p38 and JNK, but not ERK1/2 in osteoblasts, and the pretreatment of osteoblasts with the p38 inhibitor (SB203580) could block the adiponectin-induced ALP activity.


CONCLUSIONS
Adiponectin can induce human osteoblast differentiation via AdipoR1/p38 pathway.
Guo
Li-juan
LJ
Department of Endocrinology, Xiangya Hospital, Central South University, Changsha 410008, China. guo-li-juan@163.com
Xie
Hui
H
Liao
Er-yuan
EY
D052242:Adiponectin / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D006801:Humans; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D015675:Osteocalcin / Q000032:analysis; D034741:RNA, Small Interfering / Q000235:genetics; D054419:Receptors, Adiponectin / Q000096:biosynthesis*; D015398:Signal Transduction
D052242:Adiponectin; D034741:RNA, Small Interfering; D054419:Receptors, Adiponectin; D015675:Osteocalcin; D000469:Alkaline Phosphatase