State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China.
Cell Rep. 2021 Mar 9;34(10):108832. doi: 10.1016/j.celrep.2021.108832.
Hosts recognize cytosolic microbial infection via the nucleotide-binding domain-like receptor (NLR) protein family, triggering inflammasome complex assembly to provoke pyroptosis or cytokine-related caspase-1-dependent antimicrobial responses. Pathogens have evolved diverse strategies to antagonize inflammasome activation. Here, Edwardsiella piscicida gene-defined transposon library screening for lactate dehydrogenase (LDH) release in nlrc4 bone marrow-derived macrophages (BMDMs) demonstrates that genes clustered in the bacterial arginine metabolism pathway participate in NLRP3 inflammasome inhibition. Blocking arginine uptake or putrescine export significantly relieves NLRP3 inflammasome inhibition, indicating that this bacterium rewires its arginine metabolism network during infection. Moreover, intracellular E. piscicida recruits the host arginine importer (mCAT-1) and putrescine exporter (Oct-2) to bacterium-containing vacuoles, accompanied by reduced arginine and accumulated cytosolic spermine. Neutralizing E. piscicida-induced cytosolic spermine enhancement by spermine synthetase or extracellular spermine significantly alters NLRP3 inflammasome activation. Importantly, accumulated cytosolic spermine inhibits K efflux-dependent NLRP3 inflammasome activation. These data highlight the mechanism of bacterial gene-mediated arginine metabolism control for NLRP3 inflammasome evasion.
宿主通过核苷酸结合域样受体 (NLR) 蛋白家族识别细胞质微生物感染，触发炎症小体复合物组装，引发细胞焦亡或细胞因子相关的半胱天冬酶-1 依赖性抗菌反应。病原体已经进化出多种策略来拮抗炎症小体的激活。在这里，爱德华氏菌基因定义的转座子文库筛选 nlrc4 骨髓来源巨噬细胞 (BMDM) 中的乳酸脱氢酶 (LDH) 释放表明，聚集在细菌精氨酸代谢途径中的基因参与 NLRP3 炎症小体抑制。阻断精氨酸摄取或腐胺外排可显著缓解 NLRP3 炎症小体抑制，表明该细菌在感染过程中重新构建其精氨酸代谢网络。此外，细胞内的爱德华氏菌招募宿主精氨酸输入器 (mCAT-1) 和腐胺输出器 (Oct-2) 到含有细菌的空泡中，伴随着精氨酸减少和细胞溶质中的 spermine 积累。通过 spermine 合酶或细胞外 spermine 中和爱德华氏菌诱导的细胞溶质 spermine 增强会显著改变 NLRP3 炎症小体的激活。重要的是，积累的细胞溶质 spermine 抑制依赖于 K 外流的 NLRP3 炎症小体激活。这些数据强调了细菌基因介导的精氨酸代谢控制用于 NLRP3 炎症小体逃避的机制。
