MicroRNA-193b-3p regulates hepatocyte apoptosis in selenium-deficient broilers by targeting MAML1

Selenium (Se) is an important nutritional element in the diet. Apoptosis is one of the characteristic pathological changes in liver tissue resulting from Se deficiency. MicroRNA (miRNA) plays an important role in cell proliferation, differentiation, apoptosis and tumorigenesis. However, why apoptosis occurs during Se deficiency and how miRNA regulates hepatocyte apoptosis in broilers requires further study. We used a dual luciferase reporter assay system and quantitative real-time PCR (qPCR) to screen hepatocytes in Se-deficient broilers for the specificity of hepatocyte apoptosis miRNA and its target protein. We tested the apoptosis of Se-deficient broiler livers and microRNA-193b-transfected primary hepatocytes using qPCR, western blot (WB) and flow cytometry. Our studies revealed that Se deficiency led to microRNA-193b-3p (miR-193b-3p) overexpression and increased apoptosis-related gene expression, resulting in broiler hepatocyte apoptosis. Mastermind-like protein 1 (MAML1) was one of the miR-193b-3p targets, and its expression was down-regulated in miR-193b-3p-overexpressing hepatocytes. Further studies have shown that miR-193b-3p overexpression induced changes of apoptosis-related gene expression by inhibiting the release of MAML1. Interestingly, when we overexpressed miR-193b-3p, which was added to the Signal transducers and activators of transcription-1 (STAT1) inhibitor fludarabine (Flu), hepatocyte apoptosis was significantly reduced. When these results were combined, they indicated that miR-193b-3p is involved in broiler hepatocyte apoptosis in Se deficiency by regulating the target protein MAML1. This finding may provide new ideas for studying the mechanism of hepatocyte injury due to Se deficiency.