BACKGROUND Inhibition of inositol-requiring enzyme-1 alpha (IRE1α), one of the sensor signaling proteins associated with endoplasmic reticulum (ER) stress, has been shown to alleviate brain injury and improve neurological behavior in a neonatal hypoxic-ischemic encephalopathy (HIE) rat model. However, there is no information about the role of IRE1α inhibitor as well as its molecular mechanisms in preventing neuronal pyroptosis induced by NLRP1 (NOD-, LRR- and pyrin domain-containing 1) inflammasome. In the present study, we hypothesized that IRE1α can degrade microRNA-125-b-2-3p (miR-125-b-2-3p) and activate NLRP1/caspased-1 pathway, and subsequently promote neuronal pyroptosis in HIE rat model. METHODS Ten-day old unsexed rat pups were subjected to hypoxia-ischemia (HI) injury, and the inhibitor of IRE1α, STF083010, was administered intranasally at 1 h after HI induction. AntimiR-125 or NLRP1 activation CRISPR was administered by intracerebroventricular (i.c.v) injection at 24 h before HI induction. Immunofluorescence staining, western blot analysis, reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), brain infarct volume measurement, neurological function tests, and Fluoro-Jade C staining were performed. RESULTS Endogenous phosphorylated IRE1α (p-IRE1α), NLRP1, cleaved caspase-1, interleukin-1β (IL-1β), and interleukin-18 (IL-18) were increased and miR-125-b-2-3p was decreased in HIE rat model. STF083010 administration significantly upregulated the expression of miR-125-b-2-3p, reduced the infarct volume, improved neurobehavioral outcomes and downregulated the protein expression of NLRP1, cleaved caspase-1, IL-1β and IL-18. The protective effects of STF083010 were reversed by antimiR-125 or NLRP1 activation CRISPR. CONCLUSIONS IRE1α inhibitor, STF083010, reduced neuronal pyroptosis at least in part via miR-125/NLRP1/caspase-1 signaling pathway after HI.

中文翻译：

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在新生儿缺氧缺血性脑病大鼠模型中，IRE1α 抑制可通过 miR-125/NLRP1 通路减轻神经元焦亡。

背景 抑制肌醇需求酶 1 α (IRE1α) 是与内质网 (ER) 应激相关的传感器信号蛋白之一，已被证明可以减轻新生儿缺氧缺血性脑病 (HIE) 的脑损伤并改善神经行为大鼠模型。然而，目前还没有关于IRE1α抑制剂的作用及其预防NLRP1（含NOD-、LRR-和pyrin结构域1）炎性体诱导的神经元焦亡的分子机制的信息。在本研究中，我们假设IRE1α可以降解microRNA-125-b-2-3p（miR-125-b-2-3p）并激活NLRP1/caspased-1通路，随后促进HIE大鼠模型中的神经元焦亡。方法对10日龄未性别的幼鼠进行缺氧缺血（HI）损伤，并在HI诱导后1小时鼻内给予IRE1α抑制剂STF083010。在 HI 诱导前 24 小时通过脑室内 (icv) 注射进行抗 miR-125 或 NLRP1 激活 CRISPR。进行免疫荧光染色、蛋白质印迹分析、逆转录定量实时聚合酶链反应（RT-qPCR）、脑梗死体积测量、神经功能测试和Fluoro-Jade C染色。结果 内源性磷酸化 IRE1α (p-IRE1α)、NLRP1、cleaved caspase-1、白细胞介素 1β (IL-1β) 和白细胞介素 18 (IL-18) 增加，而 miR-125-b-2-3p 减少。 HIE大鼠模型。STF083010 给药显着上调 miR-125-b-2-3p 的表达，减少梗塞体积，改善神经行为结果，并下调 NLRP1、cleaved caspase-1、IL-1β 和 IL-18 的蛋白表达。STF083010 的保护作用可被 antimiR-125 或 NLRP1 激活 CRISPR 逆转。结论 IRE1α 抑制剂 STF083010 至少部分通过 HI 后的 miR-125/NLRP1/caspase-1 信号通路减少神经元焦亡。