Kerr Nadine A, Sanchez Juliana, O'Connor Gregory, Watson Brant D, Daunert Sylvia, Bramlett Helen M, Dietrich W Dalton
Miami Project to Cure Paralysis, Leonard M. Miller School of Medicine, University of Miami, 1095 NW 14th Terrace, Miami, FL, 33136, USA.
Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, USA.
Transl Stroke Res. 2022 Dec;13(6):898-912. doi: 10.1007/s12975-022-01005-8. Epub 2022 Mar 19.
Approximately 50% of stroke survivors experience gastrointestinal complications. The innate immune response plays a role in changes to the gut-brain axis after stroke. The purpose of this study is to examine the importance of inflammasome-mediated pyroptosis in disruption of the gut-brain axis after experimental stroke. B6129 mice were subjected to a closed-head photothrombotic stroke. We examined the time course of inflammasome protein expression in brain and intestinal lysate using western blot analysis at 1-, 3-, and 7-days post-injury for caspase-1, interleukin-1β, nod-like receptor protein 3 (NLRP3), and apoptosis speck-like protein containing a caspase-recruiting domain (ASC) and gasdermin-D (GSDMD) cleavage. In a separate group of mice, we processed brain tissue 24 and 72 h after thrombotic stroke for immunohistochemical analysis of neuronal and endothelial cell pyroptosis. We examined intestinal tissue for morphological changes and pyroptosis of macrophages. We performed behavioral tests and assessed gut permeability changes to confirm functional changes after stroke. Our data show that thrombotic stroke induces inflammasome activation in the brain and intestinal tissue up to 7-day post-injury as well as pyroptosis of neurons, cerebral endothelial cells, and intestinal macrophages. We found that thrombotic stroke leads to neurocognitive and motor function deficits as well as increased gut permeability. Finally, the adoptive transfer of serum-derived EVs from stroke mice into naive induced inflammasome activation in intestinal tissues. Taken together, these results provide novel information regarding possible mechanisms underlying gut complications after stroke and the identification of new therapeutic targets for reducing the widespread consequences of ischemic brain injury.
约50%的中风幸存者会出现胃肠道并发症。先天性免疫反应在中风后肠-脑轴的变化中起作用。本研究的目的是探讨炎性小体介导的细胞焦亡在实验性中风后肠-脑轴破坏中的重要性。将B6129小鼠进行闭合性头部光血栓性中风。我们在损伤后1天、3天和7天，使用蛋白质免疫印迹分析检测脑和肠裂解物中炎性小体蛋白表达的时间进程，检测半胱天冬酶-1、白细胞介素-1β、NOD样受体蛋白3（NLRP3）、含半胱天冬酶招募结构域的凋亡斑点样蛋白（ASC）和gasdermin-D（GSDMD）的裂解情况。在另一组小鼠中，我们在血栓性中风后24小时和72小时处理脑组织，用于神经元和内皮细胞焦亡的免疫组织化学分析。我们检查肠组织的形态变化和巨噬细胞的焦亡情况。我们进行行为测试并评估肠道通透性变化，以确认中风后的功能变化。我们的数据表明，血栓性中风可诱导脑和肠组织中炎性小体激活，持续至损伤后7天，以及神经元、脑内皮细胞和肠巨噬细胞的焦亡。我们发现，血栓性中风会导致神经认知和运动功能缺陷以及肠道通透性增加。最后，将中风小鼠血清来源的细胞外囊泡过继转移到未处理小鼠中，可诱导肠组织中的炎性小体激活。综上所述，这些结果提供了关于中风后肠道并发症潜在机制的新信息，并确定了减少缺血性脑损伤广泛后果的新治疗靶点。
