Yan Le-Jin, Qi Shuang, Wu Chao, Jin Rui, Hu Chen, Wang Ao-Li, Wang Bei-Lei, Yu Hong-Wei, Wang Li, Liu Jing, Qi Zi-Ping, Wang Wen-Chao, Liu Qing-Song
University of Science and Technology of China, Hefei, 230026, China.
Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
Acta Pharmacol Sin. 2025 Apr;46(4):1016-1029. doi: 10.1038/s41401-024-01434-1. Epub 2024 Dec 16.
Abnormal activation of NLRP3 inflammasome causes the progression of gout, and no small-molecule inhibitor of NLRP3 has been approved yet for clinical use. In this study we established a nigericin-induced inflammasome activation cell model for screening of a natural product library by measuring IL-1β secretion in cell supernatants. Among 432 compounds tested, we found that hypocrellin A (HA), one of the major active components of a traditional ethnic medicinal fungus Hypocrella bambusea in the Northwest Yunnan of China, exhibited the highest inhibition on IL-1β production (IC = 0.103 μM). In PMA-primed THP-1 cells or bone marrow derived macrophages (BMDMs) treated with multiple stimuli (nigericin, ATP or MSU), HA dose-dependently suppressed the activation of NLRP3 inflammasome, reducing the subsequent release of inflammatory cytokines and LDH. Furthermore, the suppression of inflammasome activation by HA was specific to NLRP3, but not to AIM2 or NLRC4. In LPS-primed BMDMs treated with nigericin, HA inhibited ASC oligomerization and speckle formation, and blocked the NLRP3-NEK7 interaction during inflammasome assembly without influencing the priming stage. Moreover, we demonstrated that HA directly bound to the NACHT domain of NLRP3, and that Arg578 and Glu629 were the critical residues for HA binding to NLRP3. In MSU-induced peritonitis and acute gouty arthritis mouse models, administration of HA (10 mg/kg, i.p., once or twice daily) effectively suppressed the inflammatory responses mediated by NLRP3 inflammasome. We conclude that HA is a broad-spectrum and specific NLRP3 inhibitor, and a valuable lead compound to develop novel therapeutic inhibitors against NLRP3-driven diseases. This study also elucidates the anti-inflammation mechanisms and molecular targets of HA, a major active component in medicinal fungus Hypocrella bambusea that has been long used by Chinese ethnic groups.
NLRP3炎性小体的异常激活会导致痛风的进展，目前尚无NLRP3小分子抑制剂获批用于临床。在本研究中，我们通过测量细胞上清液中IL-1β的分泌，建立了尼日利亚菌素诱导的炎性小体激活细胞模型，用于筛选天然产物文库。在所测试的432种化合物中，我们发现竹红菌素A（HA），一种来自中国云南西北部传统民族药用真菌竹红菌的主要活性成分之一，对IL-1β的产生具有最高抑制作用（IC = 0.103 μM）。在用多种刺激物（尼日利亚菌素、ATP或MSU）处理的佛波酯（PMA）预处理的THP-1细胞或骨髓来源的巨噬细胞（BMDM）中，HA剂量依赖性地抑制NLRP3炎性小体的激活，减少随后炎性细胞因子和乳酸脱氢酶（LDH）的释放。此外，HA对炎性小体激活的抑制作用对NLRP3具有特异性，而对AIM2或NLRC4无特异性。在用尼日利亚菌素处理的脂多糖（LPS）预处理的BMDM中，HA抑制凋亡相关斑点样蛋白（ASC）寡聚化和斑点形成，并在炎性小体组装过程中阻断NLRP3与NEK7的相互作用，而不影响启动阶段。此外，我们证明HA直接与NLRP3的NACHT结构域结合，并且精氨酸578和谷氨酸629是HA与NLRP3结合的关键残基。在MSU诱导的腹膜炎和急性痛风性关节炎小鼠模型中，给予HA（10 mg/kg，腹腔注射，每日一次或两次）可有效抑制由NLRP3炎性小体介导的炎症反应。我们得出结论，HA是一种广谱且特异性的NLRP3抑制剂，是开发针对NLRP3驱动疾病的新型治疗抑制剂的有价值的先导化合物。本研究还阐明了长期被中国少数民族使用的药用真菌竹红菌的主要活性成分HA的抗炎机制和分子靶点。
