Cytokine-mediated neurologic disease in COVID-19

项目总结 新出现的冠状病毒SARS-CoV-2引起了一场历史性的呼吸道疾病大流行(COVID- 19)。一个令人惊讶的发现是，无论是轻度还是重度新冠肺炎都与持续性神经疾病有关 症状，即使在感染消除后也是如此。患者出现各种症状，从缺陷到 注意力、计划和其他执行功能，对记忆障碍或新精神病的关注。验尸报告 对新冠肺炎患者大脑的分析未发现传染性非典型肺炎冠状病毒2型的证据 薄壁组织。然而，新冠肺炎感染与一系列神经损伤有关，包括脑梗塞， 缺血、出血和缺氧。死后标本的免疫组织化学证明 SARS-CoV-2感染与血脑屏障(BBB)破坏、血浆PRO水平升高有关。 炎性细胞因子、IL-1β、小胶质细胞活化和结节、吞神经细胞。在其他神经性毒物中 病毒感染，IL-1β通过破坏血脑促进中枢神经系统的炎症 免疫细胞的屏障和募集激活小胶质细胞，从而消除海马区的突触， 大脑中对学习和记忆至关重要的区域。在恢复过程中，IL-1β抑制神经发生，从而限制突触 恢复，并导致空间记忆缺陷。我们假设在非典期间，大脑中产生了IL-1β- CoV-2感染通过破坏血脑屏障和促进认知和记忆而加剧神经功能障碍 赤字。为了研究这一点，我们将使用新冠肺炎的C57BL/6小鼠模型，在该模型中，小鼠鼻内注射 感染B.1.351(Beta变种)，自然感染小鼠。在目标1中，我们将研究IL-1R1的作用 利用脑微血管内皮细胞(BMEC)特异性可诱导Cre杂交发出血脑屏障破坏的信号 对IL-1R牙线攻击的小鼠。我们还将确定IL-1R1信号是否促进BMECs的激活和诱导 发炎的症状。在目标2中，我们将探索IL-1R1信号是否通过抑制 正在进行的突触消除中的神经发生。首先，我们将确定IL-1R1对神经发生的影响 在使用神经干细胞(NSC)特异性的B.1.351感染期间，可诱导的Cre小鼠与IL-1R杂交 老鼠。接下来，我们测试了IL-1R1信号在通过NSC-1恢复海马三叉神经突触回路中的作用。 特异性或小胶质细胞特异性Cre-IL-1R1用牙线固定的小鼠。最后，使用与先前实验相同的小鼠，我们 将对从B.1.351中恢复的小鼠进行行为测试，以检查IL-1R1对功能的影响 发信号。在这个提案中，我们将一起探索神经学基础上的免疫学机制。 新冠肺炎期间的功能障碍。

PROJECT SUMMARY The newly emerged coronavirus, SARS-CoV-2, has caused a historic pandemic of respiratory disease (COVID- 19). One surprising finding, is that both mild and severe COVID-19 is associated with persistent neurological symptoms, even after resolution of infection. Patients present with a variety of symptoms, from deficits in attention, planning, and other executive functions, to memory impairment, or new psychoses. Post-mortem analyses of brains from individuals with COVID-19 did not find evidence of infectious SARS-CoV-2 in the parenchyma. However, COVID-19 infection is associated with an array of neurological injury, including infarcts, ischemia, hemorrhages, and hypoxia. Immunohistochemistry on post-mortem specimens demonstrated that SARS-CoV-2 infection is associated with blood-brain barrier (BBB) disruption, elevated levels of the pro- inflammatory cytokine, IL-1β, and microglial activation and nodules, and neuronophagia. In other neurovirulent viral infections, IL-1β promotes inflammation in the central nervous system via disruption of the blood-brain barrier and recruitment of immune cells that activate microglia, which eliminate synapses in the hippocampus, a brain region critical for learning and memory. During recovery, IL-1β inhibits neurogenesis, which limits synapse recovery, and induces spatial memory defects. We hypothesize that IL-1β production in the brain during SARS- CoV-2 infection potentiates neurological dysfunction by disrupting the BBB and promoting cognitive and memory deficits. To investigate this, we will use a C57Bl/6 mouse model of COVID-19, in which mice are intranasally infected with B.1.351 (Beta variant), which naturally infects mice. In Aim 1, we will investigate the role of IL-1R1 signaling on BBB disruption using a brain microvascular endothelial cell (BMEC) specific inducible Cre crossed to IL-1R floxed mice. We will also determine if IL-1R1 signaling promotes activation of BMECs and the induction of inflammation. In Aim 2, we will explore if IL-1R1 signaling impacts cognition and memory via inhibition of neurogenesis within ongoing synapse elimination. First, we will determine the impact of IL-1R1 on neurogenesis during infection with B.1.351 using neural stem cell (NSC) specific, inducible Cre mice crossed to IL-1R floxed mice. Next, we test the role of IL-1R1 signaling on recovery of the hippocampal trisynaptic cirucuit via NSC- specific or microglial-specific Cre-IL-1R1 floxed mice. Last, using the same mice as the previous experiment, we will perform behavioral tests on mice recovered from B.1.351 to examine the functional impact of IL-1R1 signaling. Together, in this proposal we will explore the immunological mechanisms that underlie neurological dysfunction during COVID-19.