Downregulation of hsa_circ_0068087 ameliorates TLR4/NF-κB/NLRP3 inflammasome-mediated inflammation and endothelial cell dysfunction in high glucose conditioned by sponging miR-197

Abstract

Diabetes mellitus (DM) is a chronic, multifactorial metabolic disease whereby insulin deficiency or resistance results in hyperglycemia. A sustained high glucose environment results in inflammation and endothelial cell dysfunction. However, the underlying mechanisms are still not entirely clear. Circular RNAs (circRNAs) are recognized as functional non-coding RNAs involved in diverse biological processes, including DM. Previous studies have found that hsa_circ_0068087 is increased in DM patients. In order to identify whether hsa_circ_0068087 plays a role in high glucose (HG)-induced inflammation and endothelial cell dysfunction Human Umbilical Vein Endothelial Cell (HUVECs), quantitative reverse transcription PCR (qRTPCR), tube formation assay, enzyme-linked immunosorbent assay (ELISA) and bifluorescein reporter experiments were employed in this study. The results showed that the expression of hsa_circ_0068087 was upregulated in HUVECs following increases in glucose. Knockdown of hsa_circ_0068087 suppressed HG-induced HUVEC dysfunction and inflammation by suppression of the TLR4/NF-κB/NLRP3 inflammasome signaling pathway. Downregulation of miR-197 reversed hsa_circ_0068087 silence-induced HUVEC dysfunction and inflammation in the HG condition. It was found that TLR4 was the target of miR-197 and that overexpression of TLR4 ameliorated miR-197-induced HUVEC dysfunction and inhibited inflammation in the HG condition. Bifluorescein report experiments confirmed that miR-197 is a potential target of hsa_circ_0068087 and that TLR4 is a potential miR-197 target. Taken together, these results suggest that downregulation of hsa_circ_0068087 ameliorates TLR4/NF-κB/NLRP3 inflammasome-mediated inflammation and endothelial cell dysfunction in the high glucose condition by sponging miR-197.