Parkin-Dependent Mitophagy Is Required for the Inhibition of ATF4 on NLRP3 Inflammasome Activation in Cerebral Ischemia-Reperfusion Injury in Rats
Parkin-Dependent Mitophagy Is Required for the Inhibition of ATF4 on NLRP3 Inflammasome Activation in Cerebral Ischemia-Reperfusion Injury in Rats
复制标题
Parkin 依赖性线粒体自噬是 ATF4 抑制大鼠脑缺血再灌注损伤中 NLRP3 炎症小体激活所必需的
DOI：
10.3390/cells8080897
复制
发表时间：
2019-08-01
期刊：
影响因子：
6
通讯作者：
Zhao, Jing
中科院分区：
文献类型：
--
作者：
He, Qi;Li, Zhenyu;Zhao, Jing
背景：nod样受体蛋白3 （NLRP3）炎性小体在脑缺血/再灌注（I/R）损伤的炎症过程中起着至关重要的作用。ATF4在脑I/R损伤的发病机制中起着关键作用，但其功能和机制尚不完全清楚。在本研究中，我们研究了ATF4是否通过抑制NLRP3炎性体激活来改善脑I/R损伤，以及线粒体自噬是否参与了这一过程。此外，我们还探讨了帕金在atf4介导的保护作用中的作用。方法：健康成年雄性sd大鼠大脑中动脉闭塞1 h，再灌注24 h。将腺相关病毒（Adeno-associated virus， AAV）和siRNA注射到大鼠体内，分别过表达和敲低ATF4的表达。AAV预处理后，大鼠体内注射线粒体分裂抑制剂mdivi-1阻断线粒体自噬活性。AAV预处理后用特异性siRNA敲低Parkin的表达。结果：数据显示，AAV诱导的ATF4过表达对脑I/R损伤具有保护作用，表现为脑梗死体积减少，神经学评分降低，HE和Nissl染色结果改善。此外，ATF4基因过表达可上调Parkin表达，增强线粒体自噬活性，抑制NLRP3炎症小体介导的炎症反应。siRNA诱导的ATF4敲低则产生相反的效果。此外，注射mdivi-1后，atf4介导的NLRP3炎性小体活化抑制受到线粒体自噬阻断的强烈影响。此外，使用siRNA敲低Parkin可有效逆转atf4介导的线粒体自噬活性增加和NLRP3炎性体活化抑制。结论：本研究表明ATF4可通过抑制NLRP3炎性体激活，从而减轻脑I/R损伤。这些结果可能为调节线粒体自噬- nlrp3炎性小体轴减轻脑I/R损伤提供了新的策略。
Background: Nod-like receptor protein 3 (NLRP3) inflammasome is a crucial contributor in the inflammatory process during cerebral ischemia/reperfusion (I/R) injury. ATF4 plays a pivotal role in the pathogenesis of cerebral I/R injury, however, its function and underlying mechanism are not fully characterized yet. In the current study, we examined whether ATF4 ameliorates cerebral I/R injury by inhibiting NLRP3 inflammasome activation and whether mitophagy is involved in this process. In addition, we explored the role of parkin in ATF4-mediated protective effects. Method: To address these issues, healthy male adult Sprague-Dawley rats were exposed to middle cerebral artery occlusion for 1 h followed by 24 h reperfusion. Adeno-associated virus (AAV) and siRNA were injected into rats to overexpress and knockdown ATF4 expression, respectively. After pretreatment with AAV, mdivi-1(mitochondrial division inhibitor-1) was injected into rats to block mitophagy activity. Parkin expression was knockdown using specific siRNA after AAV pretreatment. Result: Data showed that ATF4 overexpression induced by AAV was protective against cerebral I/R injury, as evidenced by reduced cerebral infraction volume, decreased neurological scores and improved outcomes of HE and Nissl staining. In addition, overexpression of ATF4 gene was able to up-regulate Parkin expression, enhance mitophagy activity and inhibit NLRP3 inflammasome-mediated inflammatory response. ATF4 knockdown induced by siRNA resulted in the opposite effects. Furthermore, ATF4-mediated inhibition of NLRP3 inflammasome activation was strongly affected by mitophagy blockage upon mdivi-1 injection. Besides, ATF4-mediated increase of mitophagy activity and inhibition of NLRP3 inflammasome activation were effectively reversed by Parkin knockdown using siRNA. Conclusion: Our study demonstrated that ATF4 is able to alleviate cerebral I/R injury by suppressing NLRP3 inflammasome activation through parkin-dependent mitophagy activity. These results may provide a new strategy to relieve cerebral I/R injury by modulating mitophagy-NLRP3 inflammasome axis.