A Feedback Loop Involving MicroRNA-150 and MYB Regulates VEGF Expression in Brain Microvascular Endothelial Cells After Oxygen Glucose Deprivation.

Song Zhang,Anqi Chen,Xiaolu Chen

doi:10.3389/fphys.2021.619904

Abstract

Vascular endothelial growth factor (VEGF) plays a pivotal role in regulating cerebral angiogenesis after stroke. Meanwhile, excessive VEGF expression induces increased microvascular permeability in brain, probably leading to neurological deterioration. Therefore, the appropriate level of VEGF expression is significant to the recovery of brain exposed to stroke. In this work, we demonstrate that microRNA-150 (miR-150) and its predicted target MYB form a negative feedback loop to control the level of post-stroke VEGF expression. Repression of MYB leads to decreased expression of miR-150 in brain microvascular endothelial cells (BMVECs) exposed to oxygen glucose deprivation (OGD), thus miR-150 was predicted to be down-regulated by MYB. Moreover, MYB was confirmed to be a direct target of miR-150 by using dual luciferase reporter assay. In our previous work, we have validated VEGF as another direct target of miR-150. Therefore, MYB participates in regulation of VEGF via miR-150 under OGD, forming a feedback loop with miR-150. We also find that high levels of miR-150 inhibitors combined with MYB silence contribute to further enhancement of VEGF expression in BMVECs in response to OGD. These observations suggest that the feedback loop comprised of miR-150 and MYB, which is a pivotal endogenous epigenetic regulation to control the expression levels of VEGF in BMVECs subjected to OGD.

Highlights

Fostering compensatory angiogenesis contributes to the restoration of blood supply and provides one of the most promising therapeutic strategies for cerebral ischemia (Hatakeyama et al, 2020)
Evidences have revealed MYB as a transcription factor involved in endothelial cells proliferation and migration which are key processes involved in angiogenesis (Li et al, 2013); this phenomenon can be observed in brain microvascular endothelial cells (BMVECs) during oxygen glucose deprivation (OGD) as our group has identified (He et al, 2013)
MRNA and protein levels of MYB were markedly up-regulated after OGD (Figures 1B,C) along with the enhancement of Vascular endothelial growth factor (VEGF) expression which was observed in our previous work

Summary

INTRODUCTION

Fostering compensatory angiogenesis contributes to the restoration of blood supply and provides one of the most promising therapeutic strategies for cerebral ischemia (Hatakeyama et al, 2020). Multiple biological processes including cell proliferation, differentiation, tumor progression and angiogenesis could be controlled by miRNAs (Yin et al, 2015; Tiwari et al, 2018). Among these miRNAs, miR-150 was found to be down-regulated in the blood and brain of rats subjected to Middle Cerebral Artery Occlusion (Choi et al, 2016). Functional deficiency of MYB was associated with BMVECs tube forming capacity and modulation of VEGF expression This finding highlighted a novel strategy involving MYB for controlling the expression level of VEGF through regulation of miR-150. Our study identifies a negative feedback loop involving miRNA-150 and MYB that maintains the homeostatic expression of VEGF in BMVECs under OGD

MATERIALS AND METHODS

RESULTS

DISCUSSION