Transcriptome analysis reveals brown adipogenic reprogramming in chemical compound-induced brown adipocytes converted from human dermal fibroblasts

Brown adipogenesis contributes to controlling systemic energy balance by enhancing glucose and lipid consumptions. We have previously reported chemical compound-induced brown adipocytes (ciBAs) directly converted from human dermal fibroblasts using a serum-free medium. In this study, genome-wide transcriptional analysis was performed in ciBAs in comparison with the control fibroblasts. A broad range of integrated gene expression was enhanced in functional groups including tricarboxylic acid cycle, electron transfer chain, triglycerides metabolism, fatty acid and glucose metabolism, and adaptive thermogenesis. The results suggested that the chemical conversion underwent metabolic and mitochondrial reprogramming closely associated with functions in brown/beige adipocytes. Moreover, we also compared the transcriptional changes to those of adipocyte browning in adipose tissue-derived mesenchymal stem cells (AdMSCs). Transcriptome analysis indicated that the same sets of metabolic and mitochondria-related genes were similarly changed in the adipocyte browning. Interestingly, ciBAs more expressed Ucp1, while AdMSC-derived adipocytes predominantly expressed Ucp2. UCP1 protein was also more expressed in ciBAs than in AdMSC-derived adipocytes. Based on the evidence that UCP1, but not UCP2, is responsible for adrenergic thermogenesis, ciBAs could be a promising model for human beige adipocytes applicable for basic research, drug development, and clinical uses.