RRC ID 43187
Author Kanazawa I, Yamaguchi T, Yano S, Yamauchi M, Yamamoto M, Sugimoto T.
Title Adiponectin and AMP kinase activator stimulate proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells.
Journal BMC Cell Biol
Abstract BACKGROUND:Adiponectin is a key mediator of the metabolic syndrome that is caused by visceral fat accumulation. Adiponectin and its receptors are known to be expressed in osteoblasts, but their actions with regard to bone metabolism are still unclear. In this study, we investigated the effects of adiponectin on the proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells.
RESULTS:Adiponectin receptor type 1 (AdipoR1) mRNA was detected in the cells by RT-PCR. The adenosine monophosphate-activated protein kinase (AMP kinase) was phosphorylated by both adiponectin and a pharmacological AMP kinase activator, 5-amino-imidazole-4-carboxamide-riboside (AICAR), in the cells. AdipoR1 small interfering RNA (siRNA) transfection potently knocked down the receptor mRNA, and the effect of this knockdown persisted for as long as 10 days after the transfection. The transfected cells showed decreased expressions of type I collagen and osteocalcin mRNA, as determined by real-time PCR, and reduced ALP activity and mineralization, as determined by von Kossa and Alizarin red stainings. In contrast, AMP kinase activation by AICAR (0.01-0.5 mM) in wild-type MC3T3-E1 cells augmented their proliferation, differentiation, and mineralization. BrdU assay showed that the addition of adiponectin (0.01-1.0 mug/ml) also promoted their proliferation. Osterix, but not Runx-2, appeared to be involved in these processes because AdipoR1 siRNA transfection and AICAR treatments suppressed and enhanced osterix mRNA expression, respectively.
CONCLUSION:Taken together, this study suggests that adiponectin stimulates the proliferation, differentiation, and mineralization of osteoblasts via the AdipoR1 and AMP kinase signaling pathways in autocrine and/or paracrine fashions.
Volume 8
Pages 51
Published 2007-11-29
DOI 10.1186/1471-2121-8-51
PII 1471-2121-8-51
PMID 18047638
PMC PMC2214728
MeSH 3T3 Cells Adenylate Kinase / metabolism* Adiponectin / physiology* Animals Calcification, Physiologic* Cell Differentiation* Cell Proliferation* Mice Obesity / etiology Osteoblasts / cytology* RNA, Small Interfering / pharmacology Receptors, Adiponectin / antagonists & inhibitors Receptors, Adiponectin / physiology* Signal Transduction
IF 3.066
Times Cited 136
WOS Category CELL BIOLOGY
Resource
Human and Animal Cells MC3T3-E1(RCB1126)