Endocrine Abstracts

Determining the sequence of events controlling preadipocyte commitment and subsequent terminal differentiation into adipocytes is critical to gain insight into brown and white fat physiology and metabolic dysfunction. MicroRNAs (miRNAs) are important regulators of gene expression and emerging evidence supports their involvement in adipogenesis and adipose metabolism. The aim of this study is to 1) identify miRNAs that modulate differentiation or function of white and brown adipocytes, and 2) define miRNA action in a stem cell model of adipogenesis. Small RNAseq analysis of primary mouse brown and white adipocytes identified enriched miRNAs in mature adipocytes and pre-adipocytes. miR-10b was upregulated in brown adipocytes and CRISPR/Cas9 was used to generate its functional knockout (KO) in E14 mouse embryonic stem cells (ES). Wild type (WT) and KO cells were assessed for proliferation and self-renewal and differentiated to mature adipocytes using an optimized protocol. The expression of key genes associated with pluripotency, adipogenesis and brown adipose tissue were determined. Samples were collected at different time points for qRT-PCR and RNA-sequencing. MiR-10b expression was significantly increased during ES adipocyte differentiation. Knockout of miR-10b severely compromised differentiation into adipocytes as judged by lack of lipid droplet accumulation and low expression of white and brown adipocyte marker genes (aP2 and CIDEA) as well as preadipocyte markers (Pref-1). In contrast, stem cell markers (OCT4, Nanog) were upregulated in KO clones. KO clones showed similar self-renewal and proliferation compared to WT. Transcriptomic analysis revealed that key pathways regulating ES commitment to the adipocyte lineage appear to be affected in the KO clones. This study shows that the process of differentiating mature adipocytes from stem cells is dependent on the presence of miR-10b. 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.