Adiponectin Regulates Osteoclast Formation And Bone Resorption Through The AMPK Pathway

Objective:The aim of this study was to explore the effects of adiponectin on osteoclast formation and bone resorption and to elucidate its specific mechanism from the perspective of energy metabolism.Methods:1.Representational experiment Under the induction of cytokines,osteoclast precursor cells BMMs(bone marrow-derived monocytes)and RAW264.7 cell lines were formed into osteoclasts,effect of different concentrations of adiponectin on osteoclast formation and bone resorption were determined : a.CCK-8 method to determine the safe concentration of adiponectin(including BMMs and RAW264.7 cell lines);b.During osteoclast differentiation,effect of different concentrations of adiponectin on the formation of osteoclasts was determined in BMMs and RAW264.7 cell line;c.The effect of adiponectin on osteolysis of osteoclasts was determined by studies of osteoclast F-actin rings and formation of resorption pits after osteolysis.2.Mechanism research Adiponectin receptors,osteoclast differentiation pathway-associated protein molecules and energy metabolism-related protein molecules explore the specific mechanism of adiponectin affecting osteoclast formation: a.q PCR to determine adiponectin receptor subtype;b.Western blotting to determine the effect of adiponectin on MAPK of osteoclast differentiation related protein;c.Western blotting to determine the effect of adiponectin on energy metabolism related protein AMPK;d.Western blotting clearly determined the effect of adiponectin on MAPK after adding AMPK inhibitor Compound C.Results:1.Representational experiment: a.Adiponectin exhibits toxic effects at 10 μg/m L;b.Adiponectin inhibits osteoclast formation in a concentration-dependent manner;c.As the concentration of adiponectin increases,the function of osteoclasts diminishes,and F-actin rings and bone resorption pits decrease.2.Mechanism research: a.Adiponectin acts by acting on adiponectin receptor 1(Adipo R1);b.Phosphorylation of p38 MAPK stimulated by RANKL can be significantly inhibited by adiponectin;c.Adiponectin can make AMPK phosphate,which activates the AMPK pathway;d.AMPK inhibitor Compound C eliminates the phosphorylation of p38 AMPK by adiponectin.Conclusion:Adiponectin can inhibit p38 MAPK by Adipo R1-AMPK at a non-toxic concentration,thereby inhibiting osteoclast formation and bone resorption.