Aberrant inflammasome activation contributes to the pathogenesis of various human diseases, including atherosclerosis, gout, and metabolic disorders. Elucidation of the underlying mechanism involved in the negative regulation of the inflammasome is important for developing new therapeutic targets for these diseases. Here, we showed that Raf kinase inhibitor protein (RKIP) negatively regulates the activation of the NLRP1, NLRP3, and NLRC4 inflammasomes. RKIP deficiency enhanced caspase-1 activation and IL-1β secretion via NLRP1, NLRP3, and NLRC4 inflammasome activation in primary macrophages. The overexpression of RKIP in THP-1 cells inhibited NLRP1, NLRP3, and NLRC4 inflammasome activation. RKIP-deficient mice showed increased sensitivity to Alum-induced peritonitis and Salmonella typhimurium-induced inflammation, indicating that RKIP inhibits NLRP3 and NLRC4 inflammasome activation in vivo. Mechanistically, RKIP directly binds to apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC) and competes with NLRP1, NLRP3, or NLRC4 to interact with ASC, thus interrupting inflammasome assembly and activation. The depletion of RKIP aggravated inflammasome-related diseases such as monosodium urate (MSU)-induced gouty arthritis and high-fat diet (HFD)-induced metabolic disorders. Furthermore, the expression of RKIP was substantially downregulated in patients with gouty arthritis or type 2 diabetes (T2D) compared to healthy controls. Collectively, our findings suggest that RKIP negatively regulates NLRP1, NLRP3, and NLRC4 inflammasome activation and is a potential therapeutic target for the treatment of inflammasome-related diseases.

异常的炎症小体激活导致多种人类疾病的发病机制，包括动脉粥样硬化、痛风和代谢紊乱。阐明炎症小体负调节的潜在机制对于开发这些疾病的新治疗靶点非常重要。在这里，我们发现 Raf 激酶抑制剂蛋白 (RKIP) 负向调节 NLRP1、NLRP3 和 NLRC4 炎症小体的激活。 RKIP 缺陷通过原代巨噬细胞中 NLRP1、NLRP3 和 NLRC4 炎性体激活增强 caspase-1 激活和 IL-1β 分泌。 THP-1 细胞中 RKIP 的过表达抑制了 NLRP1、NLRP3 和 NLRC4 炎症小体的激活。 RKIP 缺陷小鼠对明矾诱导的腹膜炎和鼠伤寒沙门氏菌诱导的炎症的敏感性增加，表明 RKIP 抑制体内 NLRP3 和 NLRC4 炎性体激活。从机制上讲，RKIP 直接与含有 caspase 招募结构域 (ASC) 的凋亡相关斑点样蛋白结合，并与 NLRP1、NLRP3 或 NLRC4 竞争与 ASC 相互作用，从而中断炎症小体的组装和激活。 RKIP 的耗竭会加剧炎症小体相关疾病，例如尿酸钠 (MSU) 诱发的痛风性关节炎和高脂饮食 (HFD) 诱发的代谢紊乱。此外，与健康对照相比，痛风性关节炎或 2 型糖尿病 (T2D) 患者的 RKIP 表达显着下调。总的来说，我们的研究结果表明 RKIP 负向调节 NLRP1、NLRP3 和 NLRC4 炎症小体激活，是治疗炎症小体相关疾病的潜在治疗靶点。