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PPARγ-AGPAT6 signaling mediates acetate-induced mTORC1 activation and milk fat synthesis in mammary epithelial cells of dairy cows

Published online by Cambridge University Press:  18 November 2022

Can Liu
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
Chuanping Liu
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
Xiaoqing Gong
Affiliation:
Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
Yi Jiang
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
Yang Yang
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
Jinyou Zhang
Affiliation:
Institute of Animal Husbandry and Veterinary of Heilongjiang Academy of Land Reclamation Science, Harbin 150038, China
Xiaoming Hou
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
Ye Lin*
Affiliation:
Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
*
Author for correspondence: Ye Lin, Email: linlu516@163.com

Abstract

This research communication investigated the role and the underlying mechanism of sn-1-acylglycerol-3-phosphate O-acyltransferase 6 (AGPAT6) in acetate-induced mTORC1 signaling activation and milk fat synthesis in dairy cow mammary epithelial cells. The data showed AGPAT6 knockdown significantly decreased acetate-induced phosphorylation of mTORC1 signaling molecules and intracellular triacylglycerol (TAG) content, whereas this inhibition effect was reversed after the addition of 16:0,18:1 phosphatidic acid (PA), suggesting that AGPAT6 could generate PA in response to acetate simulation, that in turn activates mTORC1 signaling. PPARγ is the upstream regulator of AGPAT6 upon acetate stimulation. Luciferase assay with clones containing various deletions and mutation in AGPAT6 promoter showed that there is a RXRα binding sequence located at −96 bp of AGPAT6 promoter. Acetate stimulation significantly increased the interaction between PPARγ and AGPAT6 via this RXRα binding site. Taken together, our data indicated that AGPAT6 could activate mTORC1 signaling by producing PA during acetate-induced milk fat synthesis, and PPARγ acts as a transcription factor to mediate the effect of acetate on AGPAT6 via RXRα.

Type
Research Article
Copyright
Copyright © The Author(s), 2022. Published by Cambridge University Press on behalf of Hannah Dairy Research Foundation

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