PNPLA3 in largemouth bass (Micropterus salmoides): Molecular cloning, functional characterization, and its role in high glucose-induced lipid synthesis

This study aimed to characterize the full-length cDNA of pnpla 3 in Micropterus salmoides , and evaluate its role in high glucose-induced lipid synthesis. The full-length cDNA of pnpla 3 was composed of 3366 nucleotides that encoded 550 amino acids. The molecular weight of Pnpla3 was 60.41044 kDa. Pnpla3 protein contained one I-superfamily conotoxin signature, one patatin domain, one (G/A) xGxxG nucleotide domain, one GxSxG lipase motif, one DGG lipase motif, one Ser47-Asp166 catalytic dyad motif, one brummer box domain, and one 148I residue. The high mRNA levels of pnpla 3 were got in perivisceral fat followed by liver, white muscle, brain and intestine. High carbohydrates diets and glucose administration resulted in a significant up-regulation of pnpla 3 mRNA levels in the liver and muscle. In the in vitro study, PNPLA3 gene silencing significantly decreased pnpla 3 mRNA levels and its protein content, and lipid droplets area in hepatocytes. Isoleucine treatment reduced pnpla 3 mRNA levels, total triglyceride and cholesterol contents, and lipid droplets area in hepatocytes subjected to high glucose. Overall, M. salmoides pnpla 3 is highly conserved, and pnpla 3 involved in the regulation of glucose metabolism. Isoleucine could alleviate high glucose-induced lipid accumulation in M. salmoides ; this might be achieved through the down-regulation of pnpla 3 expression. • M. salmoides pnpla 3 is highly conserved. • The highest levels of pnpla 3 was got in perivisceral fat followed by liver and white muscle. • pnpla 3 involved in the regulation of glucose homeostasis of M. salmoides . • Isoleucine alleviates high glucose-induced lipid accumulation in M. salmoides .