miR-19b-3pRegulated by Estrogen Controls Lipid Synthesis Through Targeting MSMO1and ELOVL5in LMH Cells

miR-19b-3pis reported to undertake various biological role, while its function and action mechanism in chicken hepatic lipid metabolism is unclear. Conservation analysis and tissue expression pattern of miR-19b-3pand its target gene were evaluated, respectively. Dual luciferase reporter system and western blot technologies were adopted to validate miR-19b-3ptarget gene. Overexpression and knockdown assays were done to explore the biological functions of miR-19b-3pand target gene in Leghorn Male Hepatoma cell line (LMH). Regulatory approaches of estrogen on miR-19b-3pand target gene expressions are analyzed through site-directed mutation combined with estrogen receptors antagonist treatment assays. The results showed that, chicken miR-19b-3pmature sequences are highly conserved among Capra hircus, Columba livia, Rattus norvegicus, Mus musculus, Cricetulus griseus, Danio rerio, Danio novaehollandiae, Orycodylus porosus, Crocodylus porosus, Gadus morhua, and widely expressed in lung, ovary, spleen, duodenum, kidney, heart, liver, leg muscle and pectoral muscle tissues. miR-19b-3pcould significantly increase intracellular triglyceride (TG) content and decrease intracellular cholesterol (TC) content via targeting methylsterol monooxygenase 1 (MSMO1) and elongase of very long chain fatty acids 5 (ELOVL5), which are highly conserved among species, in both mRNA and protein levels. Estrogen could inhibit miR-19b-3pexpression, but directly promoted MSMO1transcription via estrogen receptor α (ERα) and indirectly regulated ELOVL5expression at the transcription level. Meanwhile, estrogen could also up-regulate MSMO1and ELOVL5expression through inhibiting miR-19b-3pexpression at the post-transcription level. Taken together, these results highlight the role and regulatory mechanism of miR-19b-3pin hepatic lipid metabolism in chicken, and might produce useful comparative information for human obesity studies and biomedical research.