Autophagy has been shown to maintain neural system homeostasis during stroke. However, the molecular mechanisms underlying neuronal autophagy in ischemic stroke remain poorly understood. This study aims to investigate the regulatory mechanisms of the pathway consisting of MEG3 (maternally expressed gene 3), microRNA-378 (miR-378), and GRB2 (growth factor receptor-bound protein 2) in neuronal autophagy and neurological functional impairment in ischemic stroke. A mouse model of the middle cerebral artery occluded–induced ischemic stroke and an in vitro model of oxygen-glucose deprivation–induced neuronal injury were developed. To understand the role of the MEG3/miR-378/GRB2 axis in the neuronal regulation, the expression of proteins associated with autophagy in neurons was measured by Western blotting analysis, and neuron death was evaluated using a lactate dehydrogenase leakage rate test. First, it was found that the GRB2 gene, up-regulated in middle cerebral artery occluded–operated mice and oxygen-glucose deprivation–exposed neurons, was a target gene of miR-378. Next, miR-378 inhibited neuronal loss and neurological functional impairment in mice, as well as neuronal autophagy and neuronal death by silencing of GRB2. Confirmatory in vitro experiments showed that MEG3 could specifically bind to miR-378 and subsequently up-regulate the expression of GRB2, which in turn suppressed the activation of Akt/mTOR pathway. Taken together, these findings suggested that miR-378 might protect against neuronal autophagy and neurological functional impairment and proposed that a MEG3/miR-378/GRB2 regulatory axis contributed to better understanding of the pathophysiology of ischemic stroke.

中文翻译：

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长链非编码 RNA MEG3/MiR-378/GRB2 轴在缺血性卒中神经元自噬和神经功能障碍中的作用。

自噬已被证明可以在中风期间维持神经系统稳态。然而，缺血性卒中神经元自噬的分子机制仍然知之甚少。本研究旨在探讨由 MEG3（母体表达基因 3）、microRNA-378（miR-378）和 GRB2（生长因子受体结合蛋白 2）组成的通路在缺血性神经元自噬和神经功能障碍中的调控机制。中风。开发了大脑中动脉闭塞诱导的缺血性卒中小鼠模型和缺氧葡萄糖剥夺诱导的神经元损伤的体外模型。为了了解 MEG3/miR-378/GRB2 轴在神经元调节中的作用，通过蛋白质印迹分析测量了神经元中与自噬相关的蛋白质的表达，使用乳酸脱氢酶泄漏率测试评估神经元死亡。首先，发现在大脑中动脉闭塞手术小鼠和缺氧-葡萄糖剥夺暴露神经元中上调的 GRB2 基因是 miR-378 的靶基因。接下来，miR-378 通过沉默 GRB2 抑制小鼠的神经元丢失和神经功能障碍，以及神经元自噬和神经元死亡。验证性体外实验表明，MEG3 可以与 miR-378 特异性结合，随后上调 GRB2 的表达，进而抑制 Akt/mTOR 通路的激活。综合起来，