Overexpression of DGAT2 Regulates the Differentiation of Bovine Preadipocytes

SIMPLE SUMMARY: Beef with rich intramuscular fat deposits is considered to be of high quality, and triacylglycerols are a major component of intramuscular fat. The synthesis of triacylglycerols is regulated by diacylglycerol O-acyltransferase 2 (DGAT2). This study focused on the regulatory mechanism of DGAT2 in the differentiation of preadipocytes from Yanbian cattle and its role in lipid metabolism-related signalling pathways. Bovine preadipocytes were infected by constructing an overexpression adenovirus vector and an interfering adenovirus vector. Differentially expressed genes in bovine preadipocytes were analysed using RNA sequencing and genome databases. The results showed that during the differentiation of bovine preadipocytes, high expression of DGAT2 promoted lipid droplet formation, triglyceride content, and expression of adipogenesis genes at the messenger RNA level. Transcriptome analysis identified 208 differentially expressed genes between DGAT2-overexpressing preadipocytes and normal cells. These results indicate that DGAT2 plays an important role in the regulation of bovine fat metabolism and provides a theoretical basis for the production of high-quality marbled beef. ABSTRACT: Triacylglycerols (TAGs) are a major component of intramuscular fat. Diacylglycerol O-acyltransferase 2(DGAT2) expression determines the rate of TAG synthesis. The purpose of this study was to investigate the role of DGAT2 in the differentiation of Yanbian cattle preadipocytes and lipid metabolism-related signalling pathways. Bovine preadipocytes were infected with overexpression and interfering adenovirus vectors of DGAT2. The effects on the differentiation of Yanbian cattle preadipocytes were examined using molecular and transcriptomic techniques, including differentially expressed genes (DEGs) and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis. DGAT2 overexpression significantly increased (p < 0.05) intracellular TAG, adiponectin, and lipid droplet (LD) contents. Moreover, it upregulated (p < 0.05) peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α, and fatty acid binding protein 4 mRNA expression. In contrast, DGAT2 knockdown reduced intracellular TAG and LD content and downregulated (p < 0.05) C/EBPβ, mannosyl (alpha-1,3-)-glycoproteinbeta-1,2-N-acetylglucosaminyltransferase, lipin 1,1-acylglycerol-3-phosphate O-acyltransferase 4, and acetyl-CoA carboxylase alpha mRNA expression. Between DGAT2-overexpressing preadipocytes and normal cells, 208 DEGs were identified, including 106 upregulated and 102 downregulated genes. KEGG pathway analysis revealed DEGs mainly enriched in PPAR signalling and AMP-activated protein kinase pathways, cholesterol metabolism, and fatty acid biosynthesis. These results demonstrated that DGAT2 regulated preadipocyte differentiation and LD and TAG accumulation by mediating the expression of adipose differentiation-, lipid metabolism-, and fatty acid synthesis-related genes.