Contrary Effects of BMP-2 and ATRA on Adipogenesis in Mouse Mesenchymal Fibroblasts

This study evaluates the effects of bone morphogenetic protein 2 (BMP-2) and all trans retinoic acid (ATRA) on adipogenesis in primary mouse embryo fibroblasts (MEFs). In BMP-2-treated MEFs, lipid accumulation and substantial induction of the adipocyte specific marker 442-aP2 suggested the conversion of MEFs into adipocytes. Such adipogenesis was found to be mediated through sequential induction of C/EBPα, C/EBPβ, and PPARγ. Both the BMP/Smad and BMP/p38 pathways contributed to the adipocyte differentiation. Contrary to the effects of BMP-2, ATRA was demonstrated to inhibit adipocyte differentiation in MEFs. Semi-quantitative RT-PCR analysis revealed that ATRA caused a selective inhibition of both the basal and induction levels of C/EBPα and PPARγ, without altering the expression pattern of C/EBPβ. Taken together, these data suggest the roles of BMP-2 and ATRA in adipogenic differentiation of primary MEFs, and the possible molecular mechanism that involves the regulation of C/EBPα, C/EBPβ, and PPARγ.