MicroR-15b-5p targets JAK2/STAT3 signaling pathway to regulate glucose and lipid metabolism in primary chicken hepatocytes

Fatty liver hemorrhagic syndrome (FLHS) is a relatively common metabolic disorder in poultry, and leads to severe economic losses in the egg and associated industries. It is unclear the role of microRNA (miRNA) regulated glucose and lipid metabolism in the progression of FLHS. Our previous sequencing data identified a significant reduction of miR-15b-5p in FLHS which we further investigated in this study. The in vitro FLHS model was established by treating primary chicken hepatocytes with free fatty acids (FFAs) and an in vivo FLHS model was developed by feeding high-energy and low-protein (HELP) diet to Hy-Line brown laying hens. Both models demonstrated excessive lipid accumulation, activation of the Janus kinase 2 (JAK2)/ signal transducer and activator of transcription 3 (STAT3) pathway, concomitant with downregulation of hepatic miR-15b-5p, which were connected to upregulation of the level of lipogenic-related genes and suppression of glucose metabolism-related genes. Subsequently, dual-luciferase reporter assay results demonstrated that miR-15b-5p specifically targets binding the 3' untranslated region (3' UTR) of JAK2 and STAT3. MiR-15b-5p mimic in primary hepatocytes induced its overexpression, markedly reduced hepatic lipid accumulation, enhanced the expression of glucose metabolism-related genes and downregulated that of lipogenesis-related genes, while suppressing JAK2/STAT3 pathway activation. Conversely, when miR-15b-5p expression was suppressed, it caused exacerbated lipid accumulation, lipogenesis-related genes expression was turned up, glucose metabolism-related genes were reduced, and further activated the JAK2/STAT3 pathway. All the results support the conclusion that miR-15b-5p regulates both glucose and lipid metabolism in FLHS by targeting the JAK2/STAT3 pathway, this underscores its potential as a therapeutic value in managing this metabolic disorder.