OGR1 negatively regulates β-casein and triglyceride synthesis and cell proliferation via the PI3K/AKT/mTOR signaling pathway in goat mammary epithelial cells

Abstract

Goat milk in some cases is less allergenic than cow milk, therefore, more people drink goat milk in the world, so it is necessary for us to improve the yield and quality of goat milk. Previous studies have shown that some genes are closely related to lactation. Ovarian cancer G protein-coupled 1 (OGR1) is a G protein-coupled receptor discovered recently. OGR1 is widely found in various tissues of organisms and is involved in cell skeleton reorganization, carcinogenesis, cell proliferation, and apoptosis by regulating multiple signaling pathways in cells. However, the modulating effect of OGR1 in lactation is still unknown. Therefore, the objective of this study is to investigate the function of OGR1 in goat mammary epithelial cells (GMECs). Flow cytometry, CCK8, EDU, enzyme-linked immunosorbent assay, and triglyceride test kit assays were performed and we found that OGR1 regulated Bcl-2/Bax ratio, Fas protein expression as well as the phosphorylation of AKT and mammalian target of rapamycin (mTOR). si-OGR1 could enhance the proliferation of GMECs by promoting G1/S phase progression and the synthesis of β-casein and triglyceride. By contrast, OGR1 repressed GMECs proliferation and down-regulated the synthesis of β-casein and triglyceride by blocking the PI3K/AKT/mTOR signaling pathway in GMECs.

Keywords:

• Mammary epithelial cells
• proliferation
• PI3K/AKT/mTOR signaling pathway
• triglyceride
• goat

Ethics approval

All animal care and procedures were performed in accordance with institutional and national guidelines and approved by the institutional Animal Care and Use Committee of Northwest A&F University (China).

Acknowledgments

We thank Lei Zhang, Xiaorui Liu, Yuhan Liu, Jiuzeng Cui, Sicheng Che, Heran Cao for their help during the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was financially supported by the National Natural Science Foundation of China [31601925], the Natural Science Foundation of Shaanxi Province [2018JM3006 and 2015JM3087], the China Postdoctoral Science Foundation [2016T90954 and 2014M552498], and the Shaanxi Science and Technology Innovation Project Plan [2015KTCQ03-08, 2016KTZDNY02-04, 2017ZDXM-NY-081, and 2018ZDCXL-NY-01-04].