Abstract:

Objective To investigate the effect and mechanism of all-trans retinoic acid （ATRA） or bone morphogenetic protein 7 （BMP7） on the development of brown adipocytes in C3H10T1/2 mesenchymal stem cells. Methods C3H10T1/2 mesenchymal stem cells were pretreated with ATRA or BMP7,followed by an adipogenic cocktail. To evaluate the adipogenesis,oil red O staining was used to identify brown adipogenic capacity. Mitochondrial track staining was used to analyze mitochondrial biogenesis in mature brown adipocytes. The expressions of BMP7,brown adipogenic inhibitors （Necdin,Wnt 10a and Pref 1） and brown adipocyte-related gene were determined by real-time fluorescence quantitation polymerase chain reaction （PCR）and western blotting. Results The optimal concentration of ATRA in promoting C3H10T1/2 brown adipogenesis was 1-2 μmol/ L. After pretreatment for 3 d with 1 μmol/L ATRA （ATRA group）,the mitochondrial biogenesis gene mRNA expressions of CyctoC,Tfam and Nrf1 were increased （P<0.05）,the mRNA expressions of brown adipogenic inhibitor Necdin and its downstream target genes （Pref1 and Wnt10a） were decreased （P<0.05）,and the mRNA expression of BMP7 gene was increased （P<0.05）,compared with control group treated by dimethyl sulfoxide （DMSO）. Different concentrations of ATRA can induce BMP7 protein expression in a dose-response manner. After the pretreatment with 1 μmol/L ATRA for 0,24 and 48 h,BMP7 protein expression was increased,and Necdin protein expression was decreased. The differentiation effect of ATRA and BMP7 was comparable. Conclusions ATRA promotes brown adipogenesis of C3H10T1/2 mesenchymal stem cells via the activation of BMP7 and reduces negative modulators of brown preadipocyte differentiation.

Key words: All-trans retinoic acid, Bone morphogenetic protein 7, Brown adipocyte, Directional differentiation