Endocrine Abstracts

Improved knowledge of adipogenesis is necessary to gain insight into brown and white fat physiology. Interest in adipocyte differentiation has increased markedly over the past few years with emphasis on intersection between microRNAs (miRNAs) and the transcriptional cascade that controls adipogenesis and metabolic dysfunction. The aim of this study is to identify miRNAs that regulate white and brown adipocyte differentiation and define miRNA action in a stem cell model of adipogenesis. Small RNAseq analysis of primary mouse brown and white adipocytes identified miR-10b to be upregulated in brown adipocytes. We generated two model systems: 1) immortalized brown pre-adipocytes (BAT) treated with miRCURY miRNA Inhibitors and 2) CRISPR/Cas9 KO of miR-10b in E14 mouse embryonic stem cells (ES). Both cell models were differentiated to mature adipocytes using optimized protocols. To unravel the pathways that are affected by miR-10b depletion, a transcriptomic analysis was performed at key time points. Both cell models demonstrated that miR-10b depletion severely compromised differentiation into mature adipocytes as judged by lack of lipid droplet accumulation and low expression of white and brown adipocyte marker genes. Further examination showed that miR-10b directly affects BMP/WNT signalling pathway, which plays a crucial role during the differentiation of ES cells into adipocytes. Intriguingly, this mechanism is not affected in the BAT model. GSEA Analysis (GSEA) based on KEGG pathways revealed that fatty acid metabolism, Citrate cycle, AMPK signalling pathway and regulation of lipolysis in adipocytes were amongst the most significantly affected pathways by the depletion of miR-10b in BAT. Our research was the first to identify the importance of miR-10b upregulation during adipogenesis. miR-10b appears to control distinct molecular pathways during preadipocyte commitment and terminal differentiation. Understanding the miR-10b-mediated regulatory mechanism during adipocyte commitment and differentiation may help to generate adipose tissue-engineering strategies for cellular therapies for lipodystrophy and obesity.