Melatonin enhances the function of porcine immature Sertoli cells by inhibiting the HMGCS1-estradiol pathway.

Melatonin (MT), a neurohormone synthesized and secreted primarily by the pineal gland, is of vital function to animal reproduction. However, the effects of gene expression and metabolism exerted by MT on porcine immature Sertoli cells (iSCs) remain unclear. Here, MT treatment (10 nM, 36h) elevated mitochondrial function and reduced oxidative stress, to promote proliferation and inhibit apoptosis of porcine iSCs. Transcriptome profiling identified 39 differentially expressed genes (DEGs) (33 known and 6 novel) (MT vs. Control), mainly involved in the steroid and glutamine metabolic processes, oxidoreductase activity and G protein coupled receptor binding (GO terms), and steroid biogenesis, pyruvate metabolism and AMPK signal pathways, etc (KEGG pathways). RT-qPCR validated 6 DEGs (Phgdh, Scd, Hmgcs1, Cytb, Pck2 and Sqle), with similar expression pattern to RNA-seq. Metabolomics further showed that 14 metabolites were significantly altered. The HMGCS1 protein abundance and the estradiol level were confirmed to be significantly decreased by MT (10 nM, 36h) treatment, and direct inhibition of HMGCS1 could also significantly reduce the estradiol level. However, levels of cholesterol and lactate were unchanged. Collectively, through integrated transcriptomics and metabolomics analysis, MT is demonstrated to inhibit the HMGCS1-estradiol pathway, to enhance the function of porcine iSCs.