LITAF regulation of cell death and inflammatory responses

项目摘要 机械或生化应激对细胞膜的损伤，导致细胞死亡和天然免疫的激活。 炎症途径，并有助于许多炎症条件的病理。此外， 病原体可以分泌毛孔形成毒素(PFT)来促进感染和扰乱免疫，内源性 Gasdermin D和MLKL等孔形成蛋白被证明与炎症信号转导有关 和细胞因子的分泌。细胞进化出多种机制来修复膜损伤并维持 细胞内平衡，但我们对损伤是如何感觉到并与修复联系在一起的理解仍然不完整。 我们最近开发了一种基于转座子的正向遗传筛选方法，我们已经使用它来 确定促进对金黄色葡萄球菌α毒素诱导的细胞死亡的抵抗的基因。我们鉴定了溶酶体 膜蛋白LITAF作为细胞自主的细胞死亡抑制因子。在初步数据中，我们表明LITAF 通过激活ESCRT机制，促进将受损的膜隔离到囊泡中。 我们假设LITAF作为细胞防御孔洞形成蛋白的效应器，连接传感 膜损伤对效应器修复机制的影响。在本应用程序中，我们建议检验这一假设 通过：(1)确定LITAF的激活和功能的机制；(2)确定该途径在 肺部炎症和感染；(3)检测LITAF是否调节先天免疫信号、炎症体 巨噬细胞的活化和炎性细胞死亡。这项研究具有很高的意义，因为它将为 更深入地了解细胞对膜损伤的防御机制，以及两者之间的平衡 细胞存活和炎性细胞死亡。确定应对膜损伤和预防的策略 细胞死亡将有助于理解和治疗广泛的感染性和 炎症性疾病。

Project Summary Membrane damage by mechanical or biochemical stress, leads to cell death and activation of innate immune inflammatory pathways, and contributes to the pathology of many inflammatory conditions. Furthermore, pathogens can secrete pore-forming toxins (PFT) to promote infection and disrupt immunity, and endogenous pore-forming proteins such as Gasdermin D and MLKL have been shown to contribute to inflammatory signaling and secretion of cytokines. Cells have evolved multiple mechanisms to repair membrane damage and maintain cellular homeostasis, but our understanding of how damage is sensed and linked to repair remains incomplete. We have recently developed a transposon-based forward genetic screening approach, which we have used to identify genes that promote resistance to cell death induced by S. aureus α-toxin. We identified the lysosomal membrane protein LITAF as a cell-autonomous inhibitor of cell death. In preliminary data, we show that LITAF promotes sequestration of damaged membranes into vesicles through the activation of the ESCRT machinery. We hypothesize that LITAF acts as an effector of cellular defense against pore-forming proteins, linking sensing of membrane damage to effector mechanisms of repair. In this application, we propose to test this hypothesis by: (1) identifying the mechanisms of LITAF activation and function; (2) determining the role of this pathway in lung inflammation and infection; (3) testing whether LITAF regulates innate immune signaling, inflammasome activation and inflammatory cell death in macrophages. This research is of high significance as it will provide a deeper understanding of cellular defense mechanisms against membrane damage, and of the balance between cell survival and inflammatory cell death. Identifying strategies to counteract membrane damage and prevent cell death will contribute to understanding and treating the pathology of a wide range of infectious and inflammatory diseases.