Bta-miR-376a Targeting KLF15 Interferes with Adipogenesis Signaling Pathway to Promote Differentiation of Qinchuan Beef Cattle Preadipocytes

SIMPLE SUMMARY: Our study demonstrated that bta-miR-376a negatively regulates adipocyte proliferation and differentiation by targeting the adipogenesis signaling pathway and is thus a novel regulator of development in Qinchuan beef cattle. These findings contribute to a better understanding of adipogenesis regulated by miRNA and provide an important reference for studies on beef intramuscular fat. ABSTRACT: Intramuscular fat (IMF) is a quality index associated with the taste and juiciness of meat. The deposition of IMF is affected by genetic and non-genetic factors, such as age, slaughter location, gender of the animal, and diet. Micro-ribonucleic acids (miRNA) are transcriptional regulators involved in adipogenesis, but the specific role of miR-376a in regulation of bovine adipocytes remains unknown. Our findings indicated that miR-376a was a potential negative regulator of bovine adipocyte differentiation. A bta-miR-376a mimic inhibited mRNA and protein expression of the marker genes, CDK1, CDK2, PCNA, C/EBPα, FAS, and PPAR γ, and significantly reduced ratios (%) of S-phase cells, the number of cells stained with 5-ethynyl-2′-deoxyuridine, and adipocyte proliferation. Oil red O staining and triglyceride content analysis also confirmed that bta-miR-376a was involved in adipocyte differentiation. Luciferase activities confirmed that Krüppel-like transcription factor 15 (KLF15) was a direct target gene of bta-miR-376a, and that KLF15 was a key transcription factor in adipogenesis. Therefore, bta-miR-376a might be a target for increasing beef IMF.