Bacterial activation and evasion of a PP2A phosphatase – Pyrin - Gasdermin D axis

PP2A 磷酸酶的细菌激活和逃避 - Pyrin - Gasdermin D 轴

• 批准号: 10196593
• 负责人: Egil Lien
• 金额: $ 25.13万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-03-05 至 2023-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10196593
• 关键词: Alleles; Anti-Bacterial Agents; Attenuated; Bacteria; Bacterial Infections; Bacterial Toxins; Biological Models; CASP1 gene; Cell Death; Cells; Chemicals; Cleaved cell; Clostridium; Complex; Disease; Equilibrium; Familial Mediterranean Fever; Gastroenteritis; Goals; In Vitro; Infection; Inflammasome; Inflammation; Inflammatory; Innate Immune Response; Interleukin-18; Knowledge; Lead; Link; Mediating; Monitor; Mus; Myeloid Cells; Natural Immunity; Organ; Pasteurella pseudotuberculosis; Pathologic; Pathology; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Plague; Proteins; Research Design; Resistance; Role; Salmonella; Signal Transduction; Toxin; Type III Secretion System Pathway; Virulence; Work; Yersinia; Yersinia infections; Yersinia pestis; autoinflammatory; cytokine; experimental study; in vivo; inhibitor/antagonist; macrophage; marenostrin; novel; novel strategies; pathogen; therapy design; therapy development

Abstract: Many successful Gram-negative pathogens evade or thwart innate immunity via Type III secretion systems (T3SS), often essential for virulence. Yersinia bacteria cause infections such as gastroenteritis and plague, and is an excellent model system for studies of T3SS effects on innate immune responses. Triggering of inflammasome complexes typically culminate with activation of caspase-1 that then cleaves and matures pro- forms of inflammatory cytokines IL-1b and IL-18, cytokines with well-known antibacterial effects, and the pore- forming and pyroptosis-inducing protein Gasdermin D (GSDMD) at residue D276. GSDMD pores also allow passing of IL-1b/IL-18, but the role of GSDMD cleavage in the resistance to many bacterial infections is poorly understood. We have uncovered an extraordinarily complex set of manipulations of inflammasomes by the Yersinia T3SS. One caspase-1 activation pathway is triggered by Yersinia effector YopE, a RhoA inhibitor, and leads to substantial IL-1b/IL-18 release in myeloid cells via Pyrin inflammasomes. Many details of Pyrin activation remain unclear, but Pyrin does not appear to be directly triggered by toxins or effectors such as YopE or Clostridium TcdB, rather by pathological disturbance of host RhoA signaling. Spontaneously activating alleles of Pyrin are also linked to auto-inflammatory diseases such as familial Mediterranean fever. It is believed that inactive Pyrin is phosphorylated, and an unknown phosphatase is needed to trigger Pyrin inflammasomes. Our experiments suggest PP2A phosphatase is involved. We hypothesize that PP2A phosphatase positively regulates bacterial toxin-induced Pyrin activation leading to cleavage of caspase-1, IL-1b and GSDMD. Furthermore, effective inhibitory mechanisms such as those promoted by Yersinia T3SS effector YopM can block this effective anti-bacterial pathway to promote infection. YopM appears to specifically inhibit the T3SS induced Pyrin inflammasome, likely by interactions with several kinases. Our results suggest that attenuated Yersinia strains lacking YopM regain virulence in the absence of Pyrin or GSDMD. Our goal is to decipher the protective mechanisms against infection mediated by PP2A, Pyrin, caspase-1 and GSDMD but suppressed by YopM, in vitro and in vivo. Our work will bridge the gap of knowledge by clarifying key questions related to how Pyrin is regulated by phosphatases and kinases.

抽象的： 通过III型分泌系统，许多成功的革兰氏阴性病原体逃避或阻止先天免疫 （T3SS），通常对于毒力必不可少。耶尔森细菌引起感染，例如胃肠炎和鼠疫，以及 是研究T3SS对先天免疫反应影响的出色模型系统。触发 炎性体复合物通常以caspase-1的激活结束，然后切割并成熟 炎性细胞因子IL-1B和IL-18的形式，具有众所周知抗菌作用的细胞因子，孔 在残基D276处形成和凋亡诱导蛋白质加油D（GSDMD）。 GSDMD毛孔也允许 通过IL-1B/IL-18的传递，但是GSDMD裂解在对许多细菌感染的抗性中的作用很差 理解。我们发现了一套非常复杂的炎症操作。 Yersinia T3SS。一个caspase-1激活途径是由Yersinia效应YOPE触发的，RhoA抑制剂，并且 导致通过吡啶炎症体在髓样细胞中释放的大量IL-1B/IL-18。 pyrin的许多细节 激活尚不清楚，但吡啶似乎并未由毒素或效应子（例如yope）直接触发 或TCDB梭状芽胞杆菌，而不是宿主RhoA信号传导的病理障碍。自发激活等位基因 吡啶的胃蛋白也与自动炎症性疾病（如家族性地中海热）有关。 据信，非活性吡啶是磷酸化的，需要一个未知的磷酸酶来触发吡啶 炎症。我们的实验表明涉及PP2A磷酸酶。我们假设PP2A 磷酸酶积极调节细菌毒素诱导的吡啶活化，导致裂解 caspase-1，IL-1B和GSDMD。此外，有效的抑制机制，例如由 Yersinia T3SS效应子YOPM可以阻止这种有效的抗细菌途径促进感染。 yopm 似乎特别抑制了T3SS诱导的吡啶炎症体，可能是通过与几个相互作用的 激酶。我们的结果表明，缺乏Yopm的Yersinia菌株在没有YOPM的情况下恢复了毒力 pyrin或gsdmd。我们的目标是破译针对由PP2A介导的感染的保护机制， pyrin，caspase-1和GSDMD，但被YOPM，体外和体内抑制。我们的工作将弥合 通过阐明与吡啶如何受到磷酸酶和激酶调节有关的关键问题的知识。