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.

摘要： 许多成功的革兰氏阴性病原体通过III型分泌系统逃避或阻碍先天免疫 (T3SS)，通常是毒力所必需的。耶尔森氏菌会引起胃肠炎和鼠疫等感染，以及 是研究T3SS对先天免疫反应影响的良好模型系统。触发 炎症体复合体通常以caspase-1的激活而达到顶峰，caspase-1随后裂解并成熟于 炎性细胞因子IL-1b和IL-18的形式，具有众所周知的抗菌作用的细胞因子，以及毛孔- Gasdermin D(GSDMD)在D276位残基的形成和热下垂诱导蛋白。GSDMD毛孔还允许 IL-1b/IL-18的传递，但GSDMD裂解在许多细菌感染的抗性中的作用很差 明白了。我们已经发现了一组非常复杂的炎症体操作 耶尔森氏菌T3SS.一条caspase-1激活途径是由耶尔森氏菌效应子YopE触发的，YopE是一种RhoA抑制剂， 导致髓系细胞通过吡咯炎性小体大量释放IL-1b/IL-18。关于吡喃的许多细节 激活尚不清楚，但吡喃似乎不是由毒素或效应物(如YopE)直接触发的 或梭状芽胞杆菌TcdB，而不是宿主RhoA信号的病理性干扰。自发激活等位基因 此外，吡喃类化合物还与家族性地中海热等自发性炎症有关。 人们认为，失活的比林是磷酸化的，需要一种未知的磷酸酶来触发比林。 炎症性小体。我们的实验表明PP2A磷酸酶参与了这一过程。我们假设PP2A 磷酸酶正向调节细菌毒素诱导的吡咯酶活性，导致裂解 Caspase-1、IL-1b和GSDMD。此外，有效的抑制机制，如由 Yersinia T3SS效应子YopM可以阻断这一有效的抗菌途径，促进感染。YopM 似乎特异性地抑制T3SS诱导的吡咯炎症体，可能是通过与几个 激活剂。我们的结果表明，缺乏YopM的耶尔森氏菌减毒株在缺乏YopM的情况下恢复了毒力 吡喃或GSDMD。我们的目标是破译PP2A介导的抗感染保护机制， 体外和体内实验表明，YopM可抑制PYRIN、Caspase-1和GSDMD的表达。我们的工作将弥合 通过澄清与磷酸酶和激酶如何调节吡喃相关的关键问题来了解这一知识。