Maslinic Acid Suppresses High Glucose-induced Inflammation by Epigenetically Inhibiting TXNIP Expression

Objective: Hyperglycemia-induced inflammation and subsequent endothelial injuries ultimately lead to the pathogenesis of cardiovascular diseases associated with high mortality, such as atherosclerosis. Maslinic acid (MA) is a phytochemical with anti-inflammatory activity. However, it remains unknown whether it can inhibit diabetes-associated cardiovascular inflammation. The present study aimed to determine the effect of MA on high glucose-induced endothelial inflammation and apoptosis in human umbilical vein endothelial cells (HUVECs) and to explore the underlying mechanism. Methods: HUVECs were treated with high glucose to induce inflammation and apoptosis. Apoptosis was determined by flow cytometry. CCK-8 assay was used to examine cell viability. Production levels of cytokines were detected by quantitative realtime PCR (qPCR) and ELISA. Protein expression levels and signaling pathways activation were detected by Western blotting. RNA immunoprecipitation and qPCR were used to determine the N-6-methyladenosine (m6A) levels of target mRNAs. Results: MA promoted the recruitment of RNA demethylase ALKBH5 to TXNIP mRNA, and subsequently enhanced its m6A demethylation. By this means, MA decreased the stability of TXNIP mRNA and downregulated its expression level. Subsequently, reactive oxygen species (ROS) and production of pro-inflammatory cytokines, including TNF-alpha, IL-6 and IL-1 ss, were inhibited. And high glucose-induced apoptosis in HUVECs was inhibited by MA. Conclusion: MA ameliorates high glucose-induced endothelial inflammation and injury, serving as a new potential therapeutic application for protecting against diabetesassociated atherosclerosis and other inflammatory diseases.