TPTEP1 suppresses high glucose-induced dysfunction in retinal vascular endothelial cells by interacting with STAT3 and targeting VEGFA.

Abstract

Diabetic retinopathy (DR) is a vascular complication of diabetes mellitus that causes visual impairment and blindness. Long noncoding RNAs (lncRNAs) have been revealed to be involved in biological processes of several diseases including DR. We designed this study to investigate the specific role of TPTEP1 in DR. First, we mimicked diabetic conditions with high glucose (HG) stimulation of human retinal vascular endothelial cells (HRVECs) and measured TPTEP1 expression in HG-stimulated HRVECs using RT-qPCR analysis. Then, CCK-8, Transwell, and Matrigel tube formation assays as well as western blot analysis were performed to reveal the biological functions of TPTEP1 in HG-stimulated HRVECs. Subsequently, bioinformatics analysis, RNA pull down, luciferase reporter and ChIP assays as well as western blot analysis evaluated the relationship of TPTEP1, signal transducer and activator of transcription 3 (STAT3) and vascular endothelial growth factor A (VEGFA) in HG-stimulated HRVECs. Finally, to verify the regulation of the TPTEP1/STAT3/VEGFA axis in HG-stimulated HRVECs, rescue experiments were carried out in HG-stimulated HRVECs. TPTEP1 presented a significant downregulation in HG-stimulated HRVECs. Additionally, TPTEP1 overexpression reduced viability, migration, and angiogenesis in HG-stimulated HRVECs. Moreover, TPTEP1 suppressed phosphorylation and nuclear translocation of STAT3, and thereby downregulated VEGFA mRNA and protein levels. Furthermore, TPTEP1 overexpression-mediated suppression of HG-induced dysfunction in HRVECs was countervailed by STAT3 upregulation or VEGFA upregulation. TPTEP1 alleviated HG-induced dysfunction in HRVECs via interacting with STAT3 and targeting VEGFA.