Exosomes derived from mesenchymal stem cells mediate miR-218 and inhibit proliferation, migration, and oxidative stress in retinal vascular endothelial cells via the EGFR/Akt/mTOR signaling pathway.

Abstract

Our study aims to elucidate the impact of exosomes obtained from human umbilical cord mesenchymal stem cells (MSC-Exos) on the proliferation, migration, and oxidative stress response of human retinal vascular endothelial cells (HRECs) and the mechanism. MSC-Exos were isolated from human umbilical cord mesenchymal stem cells using a low-temperature ultrahigh-speed centrifugation method. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, scratch tests, and cellular immunofluorescence assays were utilized to assess the influence of MSC-Exos on proliferation, migration, and oxidative stress in HRECs. Additionally, quantitative real-time PCR was utilized to quantify the expression levels of miR-218 in MSC-Exos and examine the underlying mechanisms involved in the regulation of oxidative stress. Electron microscopy and particle size analysis confirmed that the morphology of MSC-Exos was conformed to the morphological characteristics of exosomes and that MSC-Exos were positive for AlIX, CD63, and CD81 but negative for CytC. Reactive oxygen species levels were increased in HRECs induced by VEGF-165 and were decreased by MSC-Exo treatment. Compared with those of VEGF-165-transfected cells, the proliferation and migration of HRECs treated with MSC-Exos were greatly reduced, and the levels of tumor necrosis factor-a and IL-1β in the supernatant of HRECs were also significantly decreased (P < .05). The expression of miR-218 in HRECs treated with MSC-Exos was higher than that in the VEGF-165-transfected group (P < .05). The expression of VEGFA, VEGFB, HIF-1α, PGF, BDGF, and TGFβ1 in HRECs treated with MSC-Exos was significantly lower than that in the VEGF-165-transfected group (P < .05). After the overexpression of miR-218, the expression of EGFR, NLRP3, p-AKT/AKT, and p-mTOR/mTOR was significantly increased in HRECs (P < .05). MSC-Exos can significantly inhibit proliferation, migration and oxidative stress in HRECs by targeting miR-218 via the EGFR/Akt/mTOR signaling pathway.