Effect of miR-425-5p on GLP-1 secretion in intestinal L cells induced by lipopolysaccharide and its mechanism / 中华内分泌代谢杂志

ABSTRACT

Objective:To investigate the effect of miR-425-5p on glucagon-like peptide-1(GLP-1) secretion in intestinal L cells induced by lipopolysaccharide(LPS), and to explore its mechanism.Methods:GLUTag cells of intestinal L cell line were incubated with LPS to determine the levels of miR-425-5p and GLP-1. Cell viability was determined by MTT assay, and cell apoptosis was detected by flow cytometry. Quantitative real time-PCR and western blot were performed to determine the expressions of miR-425-5p, phosphatase and tensin homology(PTEN), proglucagon, and GLP-1. Activity of Wnt/β-catenin signaling pathway was determined by detecting TOP/FOP ratio. Interaction among miR-425-5p, PTEN, and β-catenin was analyzed using luciferase activity assay and chromatin immunoprecipitation(ChIP)assay.Results:In GLUTag cells, with the elevation of LPS concentration, the expression of miR-425-5p and the apoptosis rate were increased, while the level of active GLP-1 and the cell viability were decreased. MiR-425-5p was involved in the regulation of LPS on GLP-1 secretion and intestinal L cell viability. Inhibition of miR-425-5p reduced the mRNA expression of proglucagon and the TOP/FOP ratio, increased PTEN protein level, and inhibited cell viability. In LPS-treated GLUTag cells, miR-425-5p increased the level of β-catenin by targeting PTEN, and β-catenin acted as a cis-acting element to induce the transcription of proglucagon and promote the secretion of GLP-1.Conclusion:In LPS-induced intestinal L cells, miR-425-5p promotes the expression of GLP-1 by targeting PTEN to modulate β-catenin.