Novel Insight Into The Potential Role of AGPAT Gene Family in Triacylglycerols Synthesis in Buffalo

Abstract Background: Acylglycerophosphate acyltransferases (AGPATs) are enzymes known to act on the second acylation step in the Kennedy (de novo) pathway to catalyze the conversion of lysophosphatidic acid (LPA) to phosphatidic acid (PA). Although AGPATs have been extensively explored by evolution, expression, and functional studies, little is known about the functional characterization of how many members of the AGPAT family are involved in the triacylglycerols (TAG) synthesis. Therefore, the objective of this study was to characterize the potential functional roles of AGPAT family members in the TAG synthesis and growth of mammary epithelial cells using comparative genomic analysis and RNA interference (RNAi) technology.Results: In the present study, a total of 13 AGPAT genes in buffalo were identified using genome-wide analysis. Among them, 12 AGPAT gene pairs were orthologous between buffalo and cattle. The comparative transcriptomic analysis and real-time quantitative reverse transcription PCR (qRT-PCR) further showed that both AGPAT1 and AGPAT6 were highly expressed in milk samples of buffalo and cattle during lactation. Notably, knockdown of AGPAT1 or AGPAT6 significantly decreased the TAG content of buffalo mammary epithelial cells (BuMEC) and bovine mammary epithelial cells (BoMEC) through regulating the mRNA expression levels of several lipogenic genes. Furthermore, the knockdown of AGPAT1 or AGPAT6 inhibited proliferation and promoted apoptosis of BuMECs; the qRT-PCR analysis of marker genes associated with cell proliferation and apoptosis supported the same conclusions. Conclusions: These findings provide new insights about the members of AGPAT family on how they regulate the TAG synthesis and growth of mammary epithelial cells in buffalo. These findings will have important implications for understanding the role of AGPAT gene for buffalo milk production performance.