Chen Chen, Liu Xiaoqin, Gong Lijie, Zhu Tianyu, Zhou Wuxi, Kong Lingyi, Luo Jianguang
Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
Biochem Pharmacol. 2021 Aug;190:114645. doi: 10.1016/j.bcp.2021.114645. Epub 2021 Jun 4.
Increasing evidence have reported that NLRP3 inflammasome has a crucial role in various kinds of immunological diseases including colitis. However, there have only a few drug candidates directly targeting inflammasomes for the therapy of colitis. Here, we first reported that Tubocapsanolide A (TA), a natural small molecule, as a novel inhibitor of NLRP3 inflammasome for the treatment of colitis. TA inhibited the activation of NLRP3 inflammasome and suppressed the secretion of IL-1β and IL-18 in macrophages. Moreover, the ASC oligomerization was inhibited by TA. The assembly of the NLRP3 inflammasome was also restrained by TA, while had little effects on potassium and chloride efflux. Biolayer interferometry analysis showed that TA could directly bind to NLRP3. Importantly, LC-MS/MS analysis further demonstrated that TA covalently bound to the cysteine 514 residue (Cys514) of NLRP3. In vivo experiments showed that TA remarkably ameliorated DSS-induced experimental colitis in mice. However, the protection of TA against DSS-induced experimental colitis was abrogated in NLRP3-deficient (Nlrp3) mice. Taken together, this study indicates TA as a novel inhibitor of NLRP3, which identifies Cys514 as a novel regulatory site of NLRP3 and suggests TA as a promising candidate compound for the treatment of colitis.
越来越多的证据表明，NLRP3炎性小体在包括结肠炎在内的各种免疫疾病中起关键作用。然而，直接靶向炎性小体用于治疗结肠炎的候选药物却很少。在此，我们首次报道了天然小分子化合物土贝母苷甲（TA）作为一种新型的NLRP3炎性小体抑制剂用于治疗结肠炎。TA抑制巨噬细胞中NLRP3炎性小体的激活，并抑制白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）的分泌。此外，TA抑制凋亡相关斑点样蛋白（ASC）的寡聚化。TA还抑制NLRP3炎性小体的组装，而对钾离子和氯离子外流影响很小。生物膜干涉分析表明TA可直接与NLRP3结合。重要的是，液相色谱-串联质谱（LC-MS/MS）分析进一步证明TA与NLRP3的半胱氨酸514残基（Cys514）共价结合。体内实验表明，TA显著改善了葡聚糖硫酸钠（DSS）诱导的小鼠实验性结肠炎。然而，在NLRP3基因敲除（Nlrp3）小鼠中，TA对DSS诱导的实验性结肠炎的保护作用消失。综上所述，本研究表明TA是一种新型的NLRP3抑制剂，确定Cys514为NLRP3的一个新的调节位点，并表明TA是治疗结肠炎的一个有前景的候选化合物。
