BMP4 and obesity due to melanocortin 4 receptor deficiency: Zhou found that proanthocyanidin extracts (PEs) from Chinese bayberry play an anti-obesity role by upregulating the expression of Sirt1, thus inducing the deacetylation of PPARγ, downregulating the expression of C/EBP-α and upregulating the expression of BMP4 to induced white-to-brown adipocyte transdifferentiation [58].