Comparative Transcriptomic Analysis of Mammary Gland Tissues Reveals the Critical Role of GPR110 in Palmitic Acid-Stimulated Milk Protein and Fat Synthesis.

The G protein coupled receptors (GPCRs) sensing nutritional signals (amino acids, fatty acids, glucose, etc.) are not fully understood. In this research, we used transcriptome-sequencing to analyze differentially expressed genes (DEGs) in mouse mammary gland tissues at puberty, lactation and involution stages, in which 8 GPCRs were selected out and verified by qRT-PCR assay. It was further identified the role of GPR110 mediating nutrients including palmitic acid (PA) and methionine (Met) to improve milk synthesis using mouse mammary epithelial cell line HC11. PA but not Met affected GPR110 expression in a dose-dependent manner. GPR110 knockdown decreased milk protein and fat synthesis and cell proliferation, and blocked the stimulation of PA on mTOR phosphorylation and SREBP-1c expression. In summary, these experimental results disclose DEGs related to lactation and reveal that GPR110 mediates PA to activate the mTOR and SREBP-1c pathways to promote milk protein and fat synthesis.