Department of Pharmacology and Therapeutics, College of Medicine, Qassim University, Buraidah 51452, Saudi Arabia; Department of Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt.
Department of Pharmacology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa 11152, Egypt.
Life Sci. 2024 Oct 1;354:122966. doi: 10.1016/j.lfs.2024.122966. Epub 2024 Aug 13.
Aberrant activation of the NLRP3 inflammasome is recognized to induce a chronic inflammatory response in the liver, ultimately leading to hepatic fibrosis. HSP90 is suggested to regulate NLRP3 activation and its downstream signaling. This study is the first to explore the potential therapeutic role of pimitespib in mitigating liver fibrosis in rats. The results of the study revealed that pimitespib effectively suppressed hepatic inflammation and fibrogenesis by modulating HSP90's control over the NFκB/NLRP3/caspase-1 axis. In vitro experiments demonstrated that pimitespib reduced LDH levels and increased hepatocyte survival, whereas in vivo, it prolonged the survival of rats with hepatic fibrosis. Additionally, pimitespib exhibited improvements in the function and microscopic characteristics of rat livers. Pimitespib effectively inhibited NFκB, which serves as the priming signal for NLRP3 activation. Pimitespib's inhibitory effect on NLRP3, identified as an HSP90 client protein, plays a central role in the observed anti-fibrotic effect. The simultaneous inhibition of both priming and activation signals of NLRP3 by pimitespib led to a reduction in caspase-1 activity and subsequent suppression of the N-terminal fragment of gasdermin D, ultimately constraining hepatocyte pyroptotic cell death. These diverse effects were associated with a decrease in the transcription of inflammatory mediators IL-1β, IL-18, and TNF-α, as well as the fibrogenic mediators TGF-β, TIMP-1, PDGF-BB, and Col1a1. Moreover, pimitespib induced the expression of HSP70, which could further contribute to the repression of fibrosis development. In summary, our findings provide an evolutionary perspective on managing liver fibrosis, positioning pimitespib as a promising candidate for anti-inflammatory and antifibrotic therapy.
NLRP3 炎性小体的异常激活被认为会在肝脏中引起慢性炎症反应,最终导致肝纤维化。HSP90 被认为可以调节 NLRP3 的激活及其下游信号通路。本研究首次探讨了 pimitespib 在减轻大鼠肝纤维化中的潜在治疗作用。研究结果表明,pimitespib 通过调节 HSP90 对 NFκB/NLRP3/caspase-1 轴的控制,有效抑制肝炎症和纤维化。体外实验表明,pimitespib 降低 LDH 水平并增加肝细胞存活率,而体内实验则延长了肝纤维化大鼠的存活时间。此外,pimitespib 改善了大鼠肝脏的功能和显微镜特征。pimitespib 有效抑制了 NFκB,NFκB 是 NLRP3 激活的启动信号。pimitespib 对 HSP90 客户蛋白 NLRP3 的抑制作用在观察到的抗纤维化作用中起着核心作用。pimitespib 对 NLRP3 的双重抑制作用,既抑制了其启动信号,又抑制了其激活信号,导致 caspase-1 活性降低,随后抑制了 gasdermin D 的 N 端片段,最终限制了肝细胞的焦亡性细胞死亡。这些不同的作用与炎症介质 IL-1β、IL-18 和 TNF-α以及纤维化介质 TGF-β、TIMP-1、PDGF-BB 和 Col1a1 的转录减少有关。此外,pimitespib 诱导了 HSP70 的表达,这可能进一步有助于抑制纤维化的发展。总之,我们的发现为管理肝纤维化提供了一个进化的视角,将 pimitespib 定位为一种有前途的抗炎和抗纤维化治疗候选药物。