Cerebral ischemia/reperfusion (I/R) injury often leads to irreversible neuronal injury and even death, and hypothermia is the only therapeutic method that has been proven to be effective. However, the molecular mechanisms underlying the effect of hypothermia treatment on I/R injury have not been fully elucidated. In the present study, we aimed to evaluate the neuroprotective effects and mechanisms of hypothermia against hypoxia/reoxygenation (H/R)-induced neuronal damage. Primary hippocampal neurons were exposed to H/R and were then treated with hypothermia. We observed that hypothermia significantly increased cellular viability, downregulated the expression of pyroptosis-related proteins-including NLR pyrin domain containing 3 (NLRP3), apoptotic speck-like protein containing CARD (ASC), cleaved Caspase-1, and Gasdermin-D (GsdmD) p30-and reduced secretion of the pro-inflammatory cytokines, IL-1β and IL-18. Additionally, pretreatment with MCC950, a specific small-molecule inhibitor of the NLRP3 inflammasome, yielded a protective effect on cellular viability that was comparable to that of hypothermia treatment. Furthermore, hypothermia also significantly elevated the expression level of phosphatase and tensin homologous protein (PTEN) and activated the phosphorylation levels of protein kinase B (Akt) and glycogen synthase kinase-3β (GSK-3β). These protective effects of hypothermia on pyroptosis-related proteins and pro-inflammatory cytokines were partially reversed by the specific PI3K/Akt inhibitor, LY294002. Moreover, the methylated level of PTEN mRNA was elevated in hippocampal neurons upon H/R, whereas this level remained stable in the hypothermia group. Therefore, our findings suggest that hypothermia protects neurons against neuronal H/R-induced pyroptosis, and that m6A-mediated activation of PTEN and the phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/Akt/GSK-3β signaling pathway may play crucial roles during this process.

中文翻译：

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低温通过 m6A 介导的 PTEN 激活和 PI3K/Akt/GSK-3β 信号通路保护神经元免受缺血/再灌注诱导的细胞焦亡。

脑缺血/再灌注（I/R）损伤往往会导致不可逆的神经元损伤甚至死亡，而低温疗法是唯一被证明有效的治疗方法。然而，低温治疗对 I/R 损伤影响的分子机制尚未完全阐明。在本研究中，我们旨在评估低温对缺氧/复氧 (H/R) 诱导的神经元损伤的神经保护作用和机制。原代海马神经元暴露于 H/R，然后进行低温治疗。我们观察到低温显着增加了细胞活力，下调了细胞焦亡相关蛋白的表达，包括含有 3 的 NLR pyrin 结构域 (NLRP3)、含有 CARD (ASC) 的凋亡斑点样蛋白、裂解的 Caspase-1、和 Gasdermin-D (GsdmD) p30-并减少促炎细胞因子 IL-1β 和 IL-18 的分泌。此外，用 NLRP3 炎性体的特异性小分子抑制剂 MCC950 预处理对细胞活力产生了与低温治疗相当的保护作用。此外，低温还显着提高了磷酸酶和张力蛋白同源蛋白 (PTEN) 的表达水平，并激活了蛋白激酶 B (Akt) 和糖原合酶激酶-3β (GSK-3β) 的磷酸化水平。低温对细胞焦亡相关蛋白和促炎细胞因子的这些保护作用被特定的 PI3K/Akt 抑制剂 LY294002 部分逆转。此外，在 H/R 后海马神经元中 PTEN mRNA 的甲基化水平升高，而这个水平在低温组中保持稳定。因此，我们的研究结果表明，低温保护神经元免受神经元 H/R 诱导的细胞焦亡，并且 m6A 介导的 PTEN 和磷脂酰肌醇-4,5-二磷酸 3-激酶 (PI3K)/Akt/GSK-3β 信号通路的激活可能在这个过程中发挥着至关重要的作用。