Can atypical response in endothelial dysfunction-related genes and microRNAs arise from low hydrogen peroxide exposure?

Objective: Vascular endothelium is a tissue in which several vasoactive substances are produced and secreted. Reactive oxygen species can cause endothelial dysfunction (ED). miRNAs can be implicated in the oxidative stress-related ED during vascular disease pathogeneses. Our aim is to investigate effect of H2O2-induced oxidative stress on expression levels of genes and miRNAs that are key players in ED.

Methods: H2O2 effect on cell viability of human umbilical-vein endothelial cells (HUVEC) at 24-hour was measured with MTT. Low sub-cytotoxic H2O2 concentrations (25, 50 µM) were selected to analyze their oxidative stress-inducing capacities with MDA assay and their effects on EDN1, NOS3, VCAM1, SERPINE1, miR21, miR22, miR126, and miR146a levels with RT-qPCR.

Results: Each tested H2O2 concentration reduced HUVEC cell viability. Fifty µM H2O2 augmented cellular MDA levels. Intriguingly, EDN1, VCAM1, and SERPINE1 and all analyzed miRNAs' levels attenuated upon H2O2 treatment whereas there was no change in NOS3 levels compared to control. There was a positive correlation between miR-21 and VCAM1.

Conclusion: Rather than individual alterations in analyzed parameters, consistent changes in our findings i.e., parallel decreases in EDN1, VCAM1, SERPINE1 mRNA levels as well as miRNAs, suggests that H2O2 concentration-dependent modulation of expression patterns can bring about various impacts on ED (Tab. 1, Fig. 5, Ref. 63).