Inflammatory cytokines and pyroptosis in Coronavirus infection

总结 人冠状病毒（hCoV）引起严重的呼吸道综合征，如SARS，MERS和正在进行的 由最近发现的SARS-Cov 2引起的Covid-19大流行。人类和鼠类研究表明， 过度的炎症，而不是病毒的复制，可能使这些感染加速发展成致命的疾病。的 该建议的首要假设是过度炎症和中性粒细胞募集 由IL-1β触发的细胞裂解和细胞裂解严重损害宿主控制感染和维持 体内平衡这一假设的推论，如果被证明是正确的，是仔细定时抑制IL-1β， 焦亡和中性粒细胞蛋白酶应该有益于治疗Covid-19和其他hCoV感染。 增加了我们研究的重要性，这些疗法已经被批准用于治疗许多人类疾病。 这一事实预示着治疗新冠肺炎和其他hCoV感染的药物将迅速获得批准。鼠标 CoV MHV-1提供了一个很好的CoV肺部感染模型，并将用于测试我们的假设， 这些具体目标：目标1。IL-1β在CoV感染过程中是否有害以及通过何种机制？我们将 检验IL-1β的过度产生驱动中性粒细胞募集到感染的肺的假设， 随之而来的组织损伤。IL-1β能够加重MHV-1肺部感染的发病机制， 在用IL-1β药理学抑制剂治疗的敏感和耐药小鼠品系中或在 缺乏IL-1β的菌株。我们将确定是否过度的中性粒细胞募集损害肺组织 通过释放中性粒细胞弹性蛋白酶。我们还将检验IL-1β抑制I型和III型的假设， 通过刺激PGE 2合成产生IFN。我们将使用遗传学和药理学方法， 研究在MHV-1感染期间，PGE 2产生的抑制如何影响IFN-I和IFN-III的产生。我们 将测试在感染的早期或晚期调节IFN-I或PGE 2的干预措施是否 对疾病的结果产生相反的影响。AIM 2.在MHV-1感染中， 哪种炎性小体会引发细胞死亡？我们将检验gasdermin D依赖性焦亡 可能以相反的方式影响冠状病毒感染的发病机制， 复制或加剧炎症。我们将检验以下假设： 上皮细胞或内皮细胞由半胱天冬酶-11介导。缺乏caspase-11表达的小鼠品系， 肺上皮或内皮细胞已在我们的实验室中产生，并将用于测试组织特异性作用 MHV-1感染期间caspase-11的表达。

SUMMARY Human Coronaviruses (hCoV) cause severe respiratory syndromes like SARS, MERS, and the ongoing pandemic of Covid-19 caused by the recently identified SARS-Cov2. Human and murine studies indicate that excessive inflammation, rather than viral replication, may precipitate these infections into lethal diseases. The overarching hypothesis of this proposal is that the excessive inflammation and neutrophil recruitment triggered by IL-1β and pyroptotic cell lysis severely impair the host ability to control infection and maintain homeostasis. The corollary of this hypothesis, if proven correct, is that carefully timed inhibition of IL-1β, pyroptosis, and neutrophil proteases should be beneficial to treat Covid-19 and other hCoV infections. Increasing the significance of our study, these therapies are already approved to treat a number of human diseases, a fact that bodes well for a rapid approval to treat Covid-19 and other hCoV infections. The mouse CoV MHV-1 provides an excellent model of CoV lung infections and will be used to test our hypothesis in these specific aims: AIM 1. Is IL-1β deleterious during CoV infection and through which mechanisms? We will test the hypothesis that excessive production of IL-1β drives neutrophil recruitment to the infected lung with consequent tissue damage. The ability of IL-1β to exacerbate the pathogenesis of MHV-1 lung infection will be studied in susceptible and resistant mouse strains treated with pharmacological inhibitors of IL-1β or in strains deficient in IL-1β. We will determine whether excessive neutrophil recruitment damages lung tissue through release of neutrophil elastase. We will also test the hypothesis that IL-1β inhibits type I and type III IFN production by stimulation of PGE2 synthesis. We will use genetic and pharmacological approaches to examine how inhibition of PGE2 production affects IFN-I and IFN-III production during MHV-1 infection. We will test whether interventions to regulate IFN-I or PGE2 in the early or late phases of the infection have opposite effect on the disease outcome. AIM 2. Is pyroptosis beneficial or deleterious in MHV-1 infection and which inflammasome triggers cell death? We will test the hypothesis that gasdermin D-dependent pyroptosis of lung cells may affect pathogenesis of coronavirus infection in opposite ways by either restricting viral replication or exacerbating inflammation. We will test the hypothesis that pyroptosis of CoV-infected lung epithelial or endothelial cells is mediated by caspase-11. Mouse strains that lack expression of caspase-11 in lung epithelial or endothelial cells have been generated in our lab and will be used to test tissue-specific role of caspase-11 during MHV-1 infection.