Baicalein suppresses high glucose-induced inflammation and apoptosis in trophoblasts by targeting the miRNA-17-5p-Mfn1/2-NF-κB pathway

Abstract

Controlling inflammation and apoptosis in trophoblasts is critical for treating gestational diabetes mellitus (GDM). Baicalein (Bai) exhibits anti-inflammatory and miRNA-related effects; however, its roles and mechanisms in GDM remain unknown. Therefore, we explored whether Bai inhibited inflammation and apoptosis in human trophoblasts (HTR8 cells) and analyzed its mechanisms. HTR8 cells pretreated with Bai were subjected to the high-glucose (HG) stimulation before analyzing their viability, cytokine production and apoptosis, followed the expression profiles of small RNA sequencing data. The effects of miR-17-5p on the inflammation, mitochondrial fission, and apoptosis were investigated by ELISA, transmission electron microscopy and flow cytometry, respectively. Moreover, miR-17-5p, Mfn1/Mfn2 levels and mitochondrial morphology in human plasma and placental tissues from GDM-complicated and normal pregnant women were examined. Bai decreased the secretion of TNF-α, IL-1β, IL-6 and apoptosis in HG-stimulated HTR8 cells, while miR-17-5p mediated the anti-inflammatory and anti-apoptotic effects of Bai. Mechanically, miR-17-5p targeted Mfn1/Mfn2 by affecting the mitochondrial fission and apoptosis via regulation of p-Drp1 (Ser 616) and p-NF-κB signaling. Moreover, overexpression of Mfn1/Mfn2 reversed miR-17-5p-elicited mitochondrial fission and inflammation in HG-stimulated HTR8 cells pretreated with Bai. Furhtermore, overexpression of Drp1 also reversed the anti-inflammatory effect of Mfn1/2 overexpression in HG-treated HTR8 cells via up-regulation of p65 phosphorylation. Finally, miR-17-5p was upregulated in human GDM plasma and placentas along with the reduced Mfn1/Mfn2. We are the first to demonstrate that bai exerts anti-inflammatory and anti-apoptotic effects on GDM, likely by targeting the miRNA-17-5p-Mfn1/2-NF-κB pathway.