Down-Regulation of miR-218-5p Promotes Apoptosis of Human Umbilical Vein Endothelial Cells Through Regulating High-Mobility Group Box-1 in Henoch-Schonlein Purpura.

BACKGROUND: Apoptosis of human umbilical vein endothelial cells (HUVECs) plays an important role in the progression of Henoch-Schonlein purpura (HSP). In the present study, we explored the function of miR-218-5p in HUVEC apoptosis and HSP development.

MATERIALS AND METHODS: HSP rat model was established and peripheral blood mononuclear cells (PBMC) were isolated. The expression of miR-218-5p and high-mobility group box-1 (HMGB1) protein in HUVECs was determined by quantitative real-time polymerase chain reaction and western blot, respectively. Cell apoptosis was detected by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. The association between miR-218-5p and HMGB1 was determined by luciferase assay. The endogenous expression of related genes was modulated with recombinant plasmids and cell transfection.

RESULTS: MiR-218-5p was down-regulated and HMGB1 was up-regulated in vessels of the lower limb of HSP rats and in HUVECs co-cultured in HSP PBMC supernatant. MiR-218-5p negatively regulated HMGB1 by targeting its 3'-untranslated regions. Over expression of miR-218-5p reversed the increased apoptosis and HMGB1 expression observed in HUVECs co-cultured in PBMC supernatant, whereas miR-218-5p knockdown showed the opposite outcomes. Furthermore, the miR-218-5p mimic demonstrated an inhibitory effect on the apoptosis of HUVECs co-cultured in PBMC supernatant, which was reversed by over expression of HMGB1. In HSP rats, over expression of miR-218-5p attenuated HSP and decreased the level of HMGB1.

CONCLUSIONS: MiR-218-5p attenuated HSP at least partly through regulating HMGB1 expression and affecting the function of HUVECs.