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

基本信息

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
项目类别：
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

项目摘要

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：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)，通常对于毒力至关重要。耶尔森氏菌会引起胃肠炎和鼠疫等感染，是研究 T3SS 对先天免疫反应影响的优秀模型系统。触发炎症小体复合物通常随着 caspase-1 的激活而达到顶峰，然后 caspase-1 裂解并成熟炎症细胞因子 IL-1b 和 IL-18 的形式，具有众所周知的抗菌作用的细胞因子，以及毛孔残基 D276 处形成和焦亡诱导蛋白 Gasdermin D (GSDMD)。 GSDMD 孔隙还允许 IL-1b/IL-18 的传递，但 GSDMD 裂解在抵抗许多细菌感染方面的作用很差明白了。我们发现了一组极其复杂的炎症小体操纵机制耶尔森氏菌 T3SS。一种 caspase-1 激活途径由耶尔森菌效应子 YopE（一种 RhoA 抑制剂）触发，并且通过 Pyrin 炎症小体导致骨髓细胞中大量 IL-1b/IL-18 释放。 Pyrin的许多细节激活仍不清楚，但 Pyrin 似乎不是由毒素或效应器（例如 YopE）直接触发或梭菌 TcdB，而是通过宿主 RhoA 信号传导的病理性干扰。自发激活等位基因吡啶还与家族性地中海热等自身炎症性疾病有关。据信，无活性的 Pyrin 被磷酸化，需要一种未知的磷酸酶来触发 Pyrin 炎症小体。我们的实验表明 PP2A 磷酸酶参与其中。我们假设 PP2A 磷酸酶正向调节细菌毒素诱导的 Pyrin 激活，导致裂解 caspase-1、IL-1b 和 GSDMD。此外，有效的抑制机制，例如由耶尔森氏菌 T3SS 效应子 YopM 可以阻断这种有效的抗菌途径，从而促进感染。约普姆似乎特异性抑制 T3SS 诱导的 Pyrin 炎症小体，可能是通过与几种相互作用激酶。我们的结果表明，缺乏 YopM 的减毒耶尔森氏菌菌株在缺乏 YopM 的情况下恢复毒力吡啶或 GSDMD。我们的目标是破译针对 PP2A 介导的感染的保护机制， Pyrin、caspase-1 和 GSDMD，但在体外和体内均被 YopM 抑制。我们的工作将弥合差距通过澄清与 Pyrin 如何受磷酸酶和激酶调节相关的关键问题来加深了解。