The NLRP3 inflammasome has been recognized as a promising therapeutic target in drug discovery for inflammatory diseases. Our initial research identified a natural sesquiterpene isoalantolactone (IAL) as the active scaffold targeting NLRP3 inflammasome. To improve its activity and metabolic stability, a total of 64 IAL derivatives were designed and synthesized. Among them, compound 49 emerged as the optimal lead, displaying the most potent inhibitory efficacy on nigericin-induced IL-1β release in THP-1 cells, with an IC₅₀ value of 0.29 μM, approximately 27-fold more potent than that of IAL (IC₅₀: 7.86 μM), and exhibiting higher metabolic stability. Importantly, 49 remarkably improved DSS-induced ulcerative colitis in vivo. Mechanistically, we demonstrated that 49 covalently bound to cysteine 279 in the NACHT domain of NLRP3, thereby inhibiting the assembly and activation of NLRP3 inflammasome. These results provided compelling evidence to further advance the development of more potent NLRP3 inhibitors based on this scaffold.

中文翻译：

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作为有效 NLRP3 炎症小体抑制剂的新型异木瓜内酯衍生物：设计、合成和生物学表征

NLRP3炎症小体已被认为是炎症性疾病药物发现中一个有前途的治疗靶点。我们的初步研究确定了天然倍半萜异花内酯 (IAL) 作为靶向 NLRP3 炎症小体的活性支架。为了提高其活性和代谢稳定性，总共设计并合成了64个IAL衍生物。其中，化合物49成为最佳先导化合物，对THP-1细胞中尼日利亚菌素诱导的IL-1β释放具有最强效的抑制作用，IC ₅₀值为0.29 μM，比IAL强约27倍(IC ₅₀ : 7.86 μM)，并表现出更高的代谢稳定性。重要的是，49显着改善了 DSS 诱导的体内溃疡性结肠炎。从机制上讲，我们证明49与NLRP3 NACHT结构域中的半胱氨酸279共价结合，从而抑制NLRP3炎症小体的组装和激活。这些结果为进一步推进基于该支架的更有效的 NLRP3 抑制剂的开发提供了令人信服的证据。