Oxygen glucose deprivation/re-oxygenation-induced neuronal cell death is associated with Lnc-D63785 m6A methylation and miR-422a accumulation

Shu Xu,Qin Jiang,Xiao-Zhong Zhou,Da-Zhuang Li,Ya Li,Ju-Ping Chen,Ting Wu

doi:10.1038/s41419-020-03021-8

Abstract

Oxygen glucose deprivation/re-oxygenation (OGD/R) induces neuronal injury via mechanisms that are believed to mimic the pathways associated with brain ischemia. In SH-SY5Y cells and primary murine neurons, we report that OGD/R induces the accumulation of the microRNA miR-422a, leading to downregulation of miR-422a targets myocyte enhancer factor-2D (MEF2D) and mitogen-activated protein kinase kinase 6 (MAPKK6). Ectopic miR-422a inhibition attenuated OGD/R-induced cell death and apoptosis, whereas overexpression of miR-422a induced significant neuronal cell apoptosis. In addition, OGD/R decreased the expression of the long non-coding RNA D63785 (Lnc-D63785) to regulate miR-422a accumulation. Lnc-D63785 directly associated with miR-422a and overexpression of Lnc-D63785 reversed OGD/R-induced miR-422a accumulation and neuronal cell death. OGD/R downregulated Lnc-D63785 expression through increased methyltransferase-like protein 3 (METTL3)-dependent Lnc-D63785 m6A methylation. Conversely METTL3 shRNA reversed OGD/R-induced Lnc-D63785 m6A methylation to decrease miR-422a accumulation. Together, Lnc-D63785 m6A methylation by OGD/R causes miR-422a accumulation and neuronal cell apoptosis.

Highlights

Ischemic stroke is a leading cause of human morbidity and mortality around the world[1,2]
oxygen and glucose deprivation (OGD)/R induces miR-422a elevation in neuronal cells To test whether OGD/R can affect miR-422a expression, differentiated SH-SY5Y cells were exposed to oxygen glucose deprivation (OGD) for 4 h, as previouslydescribed[24,25,32]
Previous studies show that miR-422a acts as a tumor suppressor in cancer cells by targeting mitogen-activated protein kinase kinase 6 (MAPKK6)[33] and myocyte enhancer factor-2D (MEF2D)[27]

Summary

Introduction

Ischemic stroke is a leading cause of human morbidity and mortality around the world[1,2]. The main pathogenesis of stroke, ischemia-reperfusion, induces significant oxidative injury to surrounding neurons[5,6], which can be mimicked in vitro by an oxygen and glucose deprivation (OGD)/. Circulating stroke-associated miR profiles reflect temporal progression and specific etiologies of ischemic stroke[14,15]. The brain-enriched microRNA-422a (miR-422a) is upregulated in acute ischemic stroke, independent of age, severity, or confounding metabolic complications[14]. In the acute phase of stroke plasma miR-422a is significantly increased, and downregulated in the sub-acute phase[16]. Following ischemia-reperfusion, miR422a is downregulated in PC12 cells[17].

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Results

Conclusion