Adiponectin and AMP kinase activator stimulate proliferation, differentiation, and mineralization of osteoblastic MC3T3-E1 cells

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.

Pathophysiological role of enhanced bone marrow adipogenesis in diabetic complications

“…147 Paradoxically, adiponectin which is secreted nearly exclusively by adipocytes has been found to prevent adipogenic differentiation in bone marrow cultures and increase trabecular bone mass by promoting osteoblastogenesis and repressing osteoclast formation. [148][149][150][151] Unlike adiponectin, the expression of leptin increases concurrently with adiposity and appears to be unaffected by diabetes. [152][153][154] Leptin appears to have contradictory effects on bone, activating the sympathetic nervous system to accelerate bone loss, as well as stimulating the osteogenic differentiation of marrow MPCs, with the net outcome dependent on its concentration.…”

Fasudil hydrochloride induces osteoblastic differentiation of stromal cell lines, C3H10T1/2 and ST2, via bone morphogenetic protein-2 expression

“…The cells were stained with 2% AgNO 3 and fixed with 2.5% NaS 2 O 3 by von Kossa method to detect phosphate deposits in bone nodules [6][7][8]. At the same time, the order plates were fixed with ice-cold 70% ethanol and stained with Alizarin red to detect calcification.…”

“…SYBR green chemistry was used to perform quantitative determinations of the mRNAs for BMP-2, collagen-I, osteocalcin, and a house keeping gene, 36B4, according to an optimized protocol [6][7][8][9]. Total RNA was taken from cultured C3H10T1/2 and ST2 cells using Trizol reagent (Invitrogen, San Diego, CA) according to the manufacturer's recommended protocol.…”

“…At the same time, the order plates were fixed with ice-cold 70% ethanol and stained with Alizarin red to detect calcification. For quantification, cells stained with Alizarin red were destained with ethylpyridium chloride, then the extracted stain was transferred to a 96-well plate, and the absorbance at 550 nm was measured using a microplate reader, as previously described [6][7][8].…”

AMP-activated protein kinase pathway and bone metabolism

“…Novel findings, described in detail in this review, have shown that AMPK plays a role in bone physiology. There are in vitro studies demonstrating that AMPK modulators regulate bone cell differentiation and function (Kanazawa et al 2007, Molinuevo et al 2010, Quinn et al 2010, Shah et al 2010, Jang et al 2011, Mai et al 2011 and two publications showing that deletions of AMPKa and b subunits in mice lead to bone loss in vivo (Quinn et al 2010, Shah et al 2010. Furthermore, AMPK activity can be regulated in bone cells by hormones, such as ghrelin and norepinephrine, that regulate food intake and energy expenditure through AMPK activation in the brain and peripheral tissues.…”