MicroRNA-200a regulates adipocyte differentiation in the domestic yak Bos grunniens

The domestic yak (Bos grunniens) is a culturally important animal that lives at high altitude and is farmed by Tibetan herders for its meat, milk, and other animal by-products. Within the animal, adipose tissue is an important store and source of energy and is used to maintain adequate body temperature during the extended cold seasons. Exploring the biomolecular role of microRNAs (miRNAs) in the regulation of growth, development, and metabolism of yak adipocytes may provide valuable insights into the physiology of adipogenesis in the yak. This study investigated whether and how miR-200a (a miRNA recently reported to promote adipogenesis in ST2 bone marrow stromal cells) regulates adipocyte differentiation in the yak. Expression levels of miR-200a gradually increased during day 0 to day 8 of adipocyte differentiation, and transfection of adipocytes with miR-200a enhanced lipid accumulation and triglyceride content compared to control (un-transfected) adipocytes. We additionally verified (using qRT-PCR analysis) that miR-200a increased the expression of adipocyte-specific genes involved in lipogenic transcription (PPARγ, ELVOL, and C/EBPα), fatty acid synthesis (ACC, ACS, SCD, and FAS), and fatty acid transport (DGAT, LPL, and FABP4). We also found that transfection of adipocytes with miR-200a resulted in suppression of the levels of noncanonical Wnt signaling transcription factors (Wnt5a, TAK1, and NLK). These results indicate that miRNA-200a plays an important role in promoting yak adipocyte differentiation that may operate via the suppression of noncanonical Wnt signaling.