Isolation and Identification of Bovine Preadipocytes and Screening of MicroRNAs Associated with Adipogenesis.

The elucidation of the mechanisms of preadipocyte differentiation and fat accumulation in adipocytes is a major work in beef cattle breeding. As important post-transcriptional regulators, microRNAs (miRNAs) take part in cell proliferation, differentiation, apoptosis, and fat metabolism through binding seed sites of targeting mRNAs. The aim of this study was to isolate and identify bovine preadipocytes and screen miRNAs associated with adipogenesis. Bovine preadipocytes were isolated from subcutaneous fatty tissue and induced to differentiate into adipocytes. Verification of preadipocytes and adipocytes was performed by qRT-PCR (real-time quantitative reverse transcription PCR), Oil Red O staining, and immunofluorescence staining. Total RNA was extracted for small RNA sequencing. The sequencing data showed that 131 miRNAs were highly expressed in adipocytes, and 119 miRNAs were highly expressed in preadipocytes. Stem-loop qPCR (stem-loop quantitative real-time PCR) results showed that the expression patterns of 11 miRNAs were consistent with the sequencing results (miR-149-5p, miR-24-3p, miR-199a-5p, miR-33a, etc.). According to KEGG pathway and Gene Ontology (GO) analyses, multiple predicted target genes were associated with lipid metabolism. In summary, this study provides a protocol of isolating bovine preadipocytes and screening various differently expressed miRNAs during preadipocyte differentiation.