Wu Qing-Rui, Yang Hui, Zhang Hui-Dan, Cai Yong-Jiang, Zheng Yan-Xiang, Fang Heng, Wang Zi-Fan, Kuang Su-Juan, Rao Fang, Huang Huan-Lei, Deng Chun-Yu, Chen Chun-Bo
School of Medicine, South China University of Technology, 510006, Guangzhou, China.
Guangdong Provincial Key Laboratory of Clinical Pharmacology, Research Center of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Southern Medical University, 510080, Guangzhou, Guangdong, China.
Cell Death Discov. 2024 Feb 20;10(1):91. doi: 10.1038/s41420-024-01840-8.
Pyroptosis plays a crucial role in sepsis, and the abnormal handling of myocyte calcium (Ca) has been associated with cardiomyocyte pyroptosis. Specifically, the inositol 1,4,5-trisphosphate receptor type 2 (IP3R2) is a Ca release channel in the endoplasmic reticulum (ER). However, the specific role of IP3R2 in sepsis-induced cardiomyopathy (SIC) has not yet been determined. Thus, this study aimed to investigate the underlying mechanism by which IP3R2 channel-mediated Ca signaling contributes to lipopolysaccharide (LPS)-induced cardiac pyroptosis. The SIC model was established in rats by intraperitoneal injection of LPS (10 mg/kg). Cardiac dysfunction was assessed using echocardiography, and the protein expression of relevant signaling pathways was analyzed using ELISA, RT-qPCR, and western blot. Small interfering RNAs (siRNA) and an inhibitor were used to explore the role of IP3R2 in neonatal rat cardiomyocytes (NRCMs) stimulated by LPS in vitro. LPS-induced NLRP3 overexpression and GSDMD-mediated pyroptosis in the rats' heart. Treatment with the NLRP3 inhibitor MCC950 alleviated LPS-induced cardiomyocyte pyroptosis. Furthermore, LPS increased ATP-induced intracellular Ca release and IP3R2 expression in NRCMs. Inhibiting IP3R activity with xestospongin C (XeC) or knocking down IP3R2 reversed LPS-induced intracellular Ca release. Additionally, inhibiting IP3R2 reversed LPS-induced pyroptosis by suppressing the NLRP3/Caspase-1/GSDMD pathway. We also found that ER stress and IP3R2-mediated Ca release mutually regulated each other, contributing to cardiomyocyte pyroptosis. IP3R2 promotes NLRP3-mediated pyroptosis by regulating ER Ca release, and the mutual regulation of IP3R2 and ER stress further promotes LPS-induced pyroptosis in cardiomyocytes.
细胞焦亡在脓毒症中起关键作用，而心肌细胞钙（Ca）处理异常与心肌细胞焦亡有关。具体而言，2型肌醇1,4,5-三磷酸受体（IP3R2）是内质网（ER）中的一种钙释放通道。然而，IP3R2在脓毒症诱导的心肌病（SIC）中的具体作用尚未确定。因此，本研究旨在探讨IP3R2通道介导的钙信号促成脂多糖（LPS）诱导的心脏细胞焦亡的潜在机制。通过腹腔注射LPS（10mg/kg）建立大鼠SIC模型。使用超声心动图评估心脏功能障碍，并通过ELISA、RT-qPCR和蛋白质免疫印迹分析相关信号通路的蛋白质表达。使用小干扰RNA（siRNA）和抑制剂来探究IP3R2在体外受LPS刺激的新生大鼠心肌细胞（NRCMs）中的作用。LPS诱导大鼠心脏中NLRP3过表达和GSDMD介导的细胞焦亡。用NLRP3抑制剂MCC950治疗可减轻LPS诱导的心肌细胞焦亡。此外，LPS增加了ATP诱导的NRCMs细胞内钙释放和IP3R2表达。用西司他丁C（XeC）抑制IP3R活性或敲低IP3R2可逆转LPS诱导的细胞内钙释放。此外，抑制IP3R2通过抑制NLRP3/Caspase-1/GSDMD途径逆转LPS诱导的细胞焦亡。我们还发现内质网应激和IP3R2介导的钙释放相互调节，促成心肌细胞焦亡。IP3R2通过调节内质网钙释放促进NLRP3介导的细胞焦亡，IP3R2与内质网应激的相互调节进一步促进LPS诱导的心肌细胞焦亡。
