Novel Insight into the Potential Role of Acylglycerophosphate Acyltransferases Family Members on Triacylglycerols Synthesis in Buffalo

Abstract

Acylglycerophosphate acyltransferases (AGPATs) are the rate-limiting enzymes for the de novo pathway of triacylglycerols (TAG) synthesis. Although AGPATs have been extensively explored by evolution, expression and functional studies, little is known on functional characterization of how many members of the AGPAT family are involved in TAG synthesis and their impact on the cell proliferation and apoptosis. Here, 13 AGPAT genes in buffalo were identified, of which 12 AGPAT gene pairs were orthologous between buffalo and cattle. 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. Knockdown of AGPAT1 or AGPAT6 significantly decreased the TAG content of buffalo mammary epithelial cells (BuMECs) and bovine mammary epithelial cells (BoMECs) by regulating lipogenic gene expression (p < 0.05). Knockdown of AGPAT1 or AGPAT6 inhibited proliferation and apoptosis of BuMECs through the expression of marker genes associated with the proliferation and apoptosis (p < 0.05). Our data confirmed that both AGPAT1 and AGPAT6 could regulate TAG synthesis and growth of mammary epithelial cells in buffalo. These findings will have important implications for understanding the role of the AGPAT gene in buffalo milk performance.

Role of Different Members of the AGPAT Gene Family in Milk Fat Synthesis in Bubalus bubalis

“…Among them, the expressions of AGPAT2 and AGPAT5 are too low for further functional analysis. The functions of AGPAT1 and AGPAT6 in BMECs have been studied in a previous report [9,33]. We selected AGPAT1 to compare this study with the previous report.…”

“…Furthermore, current studies have mainly focused on the role of the AGPAT gene family in regulating milk fat content, with few investigating its role in regulating fat composition. In a previous study, the authors identified 32 and 14 AGPAT isoform protein sequences encoded by 13 AGPAT genes predicted from the river and swamp buffalo genomes, respectively [9]. However, most of the identified AGPAT genes are only predicted by sequence analysis, and cannot be amplified from the mRNA of MFG.…”

“…Among these, AGPATs catalyze the conversion of lysophosphatidic acid (LPA) to phosphatidic acid (PA), in addition to further dephosphorylation to form diacylglycerol (DAG). AGPAT1 and AGPAT6 are highly expressed in both buffalo and cattle mammary glands during lactation, and AGPAT1 or AGPAT6 knockdown can significantly decrease the TAG content in mammary epithelial cells by regulating the expressions of lipogenic-related genes [9]. Moreover, GPATs prefer to catalyze SFA acylation, whereas AGPATs prefer to catalyze UFAs [8,10].…”

Comparative Genomic Analysis of the Thiolase Family and Functional Characterization of the Acetyl-Coenzyme A Acyltransferase-1 Gene for Milk Biosynthesis and Production of Buffalo and Cattle

“…Identification of functional markers for milk production traits has drawn significant attention from the scientific community and breeders. ,, Previous studies have demonstrated that ACAA1 polymorphism was associated with breast cancer risk and loin-eye area in beef. , However, the association between ACAA1 polymorphism and milk production remains unclear. In this study, we identified five SNPs in the buffalo ACAA1 gene, of which three SNPs were associated with milk production traits.…”

“…Identification of functional markers for milk production traits has drawn significant attention from the scientific community and breeders. 49,50,53 Previous studies have demonstrated that ACAA1 polymorphism was associated with breast cancer risk and loin-eye area in beef. 50,51 However, the association between ACAA1 polymorphism and milk production remains unclear.…”