Department of Pharmacy, Inner Mongolia People's Hospital, Hohhot, China; Department of Hepatology, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China; China Military Institute of Chinese Materia, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China.
Department of Hepatology, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China; China Military Institute of Chinese Materia, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China; School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing, China.
Phytomedicine. 2024 Aug;131:155758. doi: 10.1016/j.phymed.2024.155758. Epub 2024 May 28.
The adaptor protein apoptosis-associated speck-like protein (ASC) containing a caspase recruitment domain (CARD) can be activated through pyrin domain (PYD) interactions between sensors and ASC, and through CARD interactions between caspase-1 and ASC. Although the majority of ternary inflammasome complexes depend on ASC, drugs targeting ASC protein remain scarce. After screening natural compounds from Isatidis Radixin, we found that tryptanthrin (TPR) could inhibit NLRP3-induced IL-1β and caspase-1 production, but the underlying anti-inflammatory mechanisms remain to be elucidated.
The purpose of this study was to determine the impact of TPR on the NLRP3, NLRC4, and AIM2 inflammasomes and the underlying mechanisms. Additionally, the efficacy of TPR was analysed in the further course of methionine- and choline-deficient (MCD)-induced NASH and lipopolysaccharide (LPS)-induced sepsis models of mice.
In vitro studies used bone marrow-derived macrophages to assess the anti-inflammatory activity of TPR, and the techniques included western blot, testing of intracellular K and Ca, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), co-immunoprecipitation, ASC oligomerization assay, surface plasmon resonance (SPR), and molecular docking. We used LPS-induced sepsis models and MCD-induced NASH models in vivo to evaluate the effectiveness of TPR in inhibiting inflammatory diseases.
Our observations suggested that TPR could inhibit NLRP3, NLRC4, and AIM2 inflammasome activation. As shown in a mouse model of inflammatory diseases caused by MCD-induced NASH and LPS-induced sepsis, TPR significantly alleviated the progression of diseases. TPR interrupted the interactions between ASC and NLRP3/NLRC4/AIM2 in the co-immunoprecipitation experiment, and stable binding of TPR to ASC was also evident in SPR experiments. The underlying mechanisms of anti-inflammatory activities of TPR might be associated with targeting ASC, in particular, PYD domain of ASC.
In general, the requirement for ASC in multiple inflammasome complexes makes TPR, as a novel broad-spectrum inflammasome inhibitor, potentially useful for treating a wide range of multifactorial inflammasome-related diseases.
衔接蛋白凋亡相关斑点样蛋白（ASC）含有半胱氨酸天冬氨酸蛋白酶募集结构域（CARD），可通过传感器与 ASC 之间的吡喃结构域（PYD）相互作用以及 caspase-1 和 ASC 之间的 CARD 相互作用而被激活。尽管大多数三元炎症小体复合物依赖 ASC，但针对 ASC 蛋白的药物仍然很少。从靛蓝根筛选天然化合物后，我们发现色烯（TPR）可以抑制 NLRP3 诱导的 IL-1β 和 caspase-1 的产生，但潜在的抗炎机制仍有待阐明。
本研究旨在确定 TPR 对 NLRP3、NLRC4 和 AIM2 炎症小体的影响及其潜在机制。此外，还分析了 TPR 在蛋氨酸和胆碱缺乏（MCD）诱导的 NASH 和脂多糖（LPS）诱导的脓毒症小鼠模型中的疗效。
体外研究采用骨髓来源的巨噬细胞来评估 TPR 的抗炎活性，所采用的技术包括 Western blot、细胞内 K 和 Ca 检测、免疫荧光、酶联免疫吸附试验（ELISA）、免疫共沉淀、ASC 寡聚化测定、表面等离子体共振（SPR）和分子对接。我们使用 LPS 诱导的脓毒症模型和 MCD 诱导的 NASH 模型体内来评估 TPR 抑制炎症性疾病的有效性。
我们的观察表明，TPR 可以抑制 NLRP3、NLRC4 和 AIM2 炎症小体的激活。在 MCD 诱导的 NASH 和 LPS 诱导的脓毒症引起的炎症性疾病的小鼠模型中，TPR 显著缓解了疾病的进展。在免疫共沉淀实验中，TPR 中断了 ASC 与 NLRP3/NLRC4/AIM2 之间的相互作用，SPR 实验也显示 TPR 与 ASC 稳定结合。TPR 抗炎活性的潜在机制可能与靶向 ASC 有关，特别是 ASC 的 PYD 结构域。
一般来说，ASC 在多种炎症小体复合物中的必要性使 TPR 成为一种新型的广谱炎症小体抑制剂，可能对治疗多种多因素炎症小体相关疾病具有重要意义。
