Laboratory of Nutrition and Development, Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China.
Front Immunol. 2021 Aug 26;12:741839. doi: 10.3389/fimmu.2021.741839. eCollection 2021.
The dysregulation of NLRP3 inflammasome plays a critical role in pathogenesis of various human inflammatory diseases, thus NLRP3 inflammasome activation must be tightly controlled at multiple levels. However, the underlying mechanism regulating NLRP3 inflammasome activation remains unclear. Herein, the effects of Tripartite motif-containing protein 65 (TRIM65) on NLRP3 inflammasome activation and the underlying molecular mechanism were investigated and . Inhibition or deletion of could significantly strengthen agonist induced NLRP3 inflammasome activation in THP-1 cells and BMDMs, indicated by increased caspase-1 activation and interleukin-1β secretion. However, TRIM65 had no effect on poly (dA: dT)-induced AIM2 inflammasome activation or flagellin-induced IPAF inflammasome activation. Mechanistically, immunoprecipitation assays demonstrated that TRIM65 binds to NACHT domain of NLRP3, promotes lys48- and lys63- linked ubiquitination of NLRP3 and restrains the NEK7-NLRP3 interaction, thereby inhibiting NLRP3 inflammasome assembly, caspase-1 activation, and IL-1β secretion. , three models of inflammatory diseases were used to confirm the suppression role of TRIM65 in NLRP3 inflammasome activation. TRIM65-deficient mice had a higher production of IL-1β induced by lipopolysaccharide in sera, and more IL-1β secretion and neutrophil migration in the ascites, and more severity of joint swelling and associated IL-1β production induced by monosodium urate, suggesting that TRIM65 deficiency was susceptible to inflammation. Therefore, the data elucidate a TRIM65-dependent negative regulation mechanism of NLRP3 inflammasome activation and provide potential therapeutic strategies for the treatment of NLRP3 inflammasome-related diseases.
NLRP3 炎性小体的失调在各种人类炎症性疾病的发病机制中起着关键作用，因此 NLRP3 炎性小体的激活必须在多个水平上受到严格控制。然而，调节 NLRP3 炎性小体激活的潜在机制尚不清楚。在此，研究了三结构域蛋白 65（TRIM65）对 NLRP3 炎性小体激活的影响及其潜在的分子机制。发现抑制或缺失 可以显著增强激动剂诱导的 THP-1 细胞和 BMDMs 中的 NLRP3 炎性小体激活，表现为 caspase-1 激活和白细胞介素-1β 分泌增加。然而，TRIM65 对聚（dA:dT）诱导的 AIM2 炎性小体激活或鞭毛蛋白诱导的 IPAF 炎性小体激活没有影响。机制上，免疫沉淀试验表明，TRIM65 与 NLRP3 的 NACHT 结构域结合，促进 NLRP3 的赖氨酸 48 和赖氨酸 63 连接的泛素化，并抑制 NEK7-NLRP3 相互作用，从而抑制 NLRP3 炎性小体组装、caspase-1 激活和 IL-1β 分泌。此外，使用三种炎症性疾病模型证实了 TRIM65 对 NLRP3 炎性小体激活的抑制作用。脂多糖诱导的血清中白细胞介素-1β 的产生、腹水白细胞介素-1β 的分泌和中性粒细胞迁移以及尿酸单钠诱导的关节肿胀和相关白细胞介素-1β 产生的严重程度在 TRIM65 缺陷型小鼠中均升高，提示 TRIM65 缺陷型小鼠易发生炎症。因此，该研究阐明了 TRIM65 依赖性 NLRP3 炎性小体激活的负调控机制，并为 NLRP3 炎性小体相关疾病的治疗提供了潜在的治疗策略。
