Resveratrol inhibits hydrogen peroxide-induced apoptosis in endothelial cells via the activation of PI3K/Akt by miR-126.

AIM: Resveratrol(RSV) is an edible polyphenolic phytoalexin present in different plant species that plays an important role in improving endothelial dysfunction. However, the molecular mechanisms underlying these effects are unknown. In the present study, the mechanism underlying the protection of CRL-1730 cells by RSV against oxidative stress was examined. METHODS: We first assessed the effects of RSV on the cell viability and apoptosis of CRL-1730 cells exposed to hydrogen peroxide(H2O2). Real-time PCR was used to determine the microRNA-126(miR-126) expression in cells treated with RSV and/or H2O2. We also evaluated the PI3K/Akt signaling pathway in CRL-1730 cells following upregulation of the miR-126 expression. Finally, we determined the effects of miR-126 on RSV against oxidative injury using an miR-126 inhibitor. RESULTS: Treatment with RSV resulted in a significant increase in survival and a decrease in the apoptosis of CRL-1730 cells exposed to H2O2. We also found that H2O2 significantly suppressed the expression of miR-126, which was reversed by RSV in a dose-dependent manner. The overexpression of miR-126 decreased PIK3R2(p85-ß) and enhanced Akt phosphorylation, which resulted in an increase in the survival of CRL-1730 cells exposed to H2O2. More importantly, the downregulation of the miR-126 expression reversed the effects of RSV on the survival and apoptosis of CRL-1730 cells exposed to H2O2. In addition, the knockdown of Ets-1 reversed the effects of RSV on the miR-126 expression in CRL-1730 cells exposed to H2O2. CONCLUSIONS: In this study, we demonstrated that the protection of endothelial cells by RSV against oxidative injury is due to the activation of PI3K/Akt by miR-126.

[Effects of mixed-tocopherols and eicosapentaenoic acid on oxidized LDL-induced oxidative damage and inflammatory cytokine secretion in human umbilical vein endothelial cells].

OBJECTIVE: To observe the influence of either alone or combined mixed-tocopherols combined with eicosapentaenoic acid (EPA) and α-Tocopherol use on oxidized LDL (oxLDL) induced 8-hydroxy-2'-deoxyguanosine (8-OHDG) and interleukin-6 (IL-6) secretion by human umbilical vein endothelial cells (HUVECs) and to explore the potential mechanism. METHOD: Cultured HUVECs in vitro were incubated with oxLDL, oxLDL + α-tocopherol, oxLDL + mixed-tocopherols, oxLDL + EPA, oxLDL + α-tocopherol + EPA, oxLDL + mixed-tocopherols + EPA for 24 hours, respectively. Secretion of 8-OHDG and IL-6 were detected by cell enzyme linked immunosorbent assay (ELISA). The expressions of superoxide dismutase (SOD), protein kinase C-δ (PKC-δ), phosphorylated PKC-δ (p-PKC-δ) were analyzed by Western blot. RESULTS: 8-OHDG and IL-6 secretion of HUVECs was significantly increased significantly after incubated with oxLDL for 24 hours which could be significantly attenuated in the presence of tocopherols and EPA (alone or in combination, all P < 0.05) while the strongest inhibition effects were seen with combined use of mixed-tocopherols and EPA. Moreover, combination of mixed-tocopherols and EPA could also significantly increase SOD activity and decrease PKC activity (all P < 0.05). However, the protein expression of SOD and PKC-was similar among groups. CONCLUSION: Combined mixed-tocopherols + EPA use enhanced the inhibiting effects on the secretion of 8-OHDG and IL-6 in oxLDL stimulated HUVECs which might be linked with increased SOD activity and reduced p-PKC activity.