Liu Zhantao, Zhang Qingsong, Su Dan, Chen Hong, Wang Bowen, Ye Lin, Wang Peiyan, Wu Jingnan, Jia Wencan, Liu Lijun, Wang Jianxun, Miao Shuo
School of Basic Medicine, Qingdao University, Qingdao, China.
Affiliated Hospital of Qingdao University, Qingdao, China.
Basic Res Cardiol. 2025 Jun 15. doi: 10.1007/s00395-025-01122-z.
Ferroptosis is an important cause of cardiomyocyte loss and cardiac dysfunction. Cathelicidin-related antimicrobial peptide (CRAMP) is an endogenous polypeptide that regulates oxidative stress in the body and is involved in ferroptosis. However, its specific role and mechanism in ferroptosis are unclear. To analyze the role of CRAMP in ferroptosis, we first analyzed its expression in infarcted myocardial tissues, and verified its role in ferroptosis in vitro through overexpression and knock-down techniques. The activity and expression of cathepsin L (CTSL) and its effect on ferroptosis were analyzed to verify whether CTSL participated in ferroptosis as a downstream of CRAMP. Protein disulfide isomerase family A member 4 (PDIA4) was screened as an interacting protein of CTSL by using the database, and the role of PDIA4 in ferroptosis was analyzed by gene knockdown and overexpression. Finally, the regulatory mechanism of CRAMP in ferroptosis was verified in vivo by mouse myocardial infarction model. CRAMP levels were reduced in both infarcted cardiac tissues and cardiomyocytes exposed to ferroptosis inducers. The overexpression of CRAMP or pretreatment of LL-37 alleviated cardiomyocyte ferroptosis, whereas CRAMP knockdown exacerbated cell death. Under ferroptotic stress, the expression of CTSL was elevated. CRAMP inhibited ferroptosis by antagonizing the CTSL activity. Abnormal increase in CTSL activity and levels caused PDIA4 to decrease. Overexpression of PDIA4 inhibited ferroptosis induced by CTSL, while knocking down PDIA4 counteracted the protection of CRAMP. In vivo, both CRAMP overexpression and administration of CRAMP peptide significantly ameliorated myocardial injury and improved cardiac function. CRAMP increases PDIA4 levels by inhibiting the activity of CTSL and antagonizes ferroptosis in cardiomyocytes. Targeting CRAMP offers innovative therapeutic strategies and insights for the prevention and management of myocardial injury.
铁死亡是心肌细胞丢失和心脏功能障碍的重要原因。cathelicidin相关抗菌肽（CRAMP）是一种调节体内氧化应激并参与铁死亡的内源性多肽。然而，其在铁死亡中的具体作用和机制尚不清楚。为了分析CRAMP在铁死亡中的作用，我们首先分析了其在梗死心肌组织中的表达，并通过过表达和敲低技术在体外验证了其在铁死亡中的作用。分析了组织蛋白酶L（CTSL）的活性和表达及其对铁死亡的影响，以验证CTSL是否作为CRAMP的下游参与铁死亡。通过数据库筛选出PDIA4作为CTSL的相互作用蛋白，并通过基因敲低和过表达分析了PDIA4在铁死亡中的作用。最后，通过小鼠心肌梗死模型在体内验证了CRAMP在铁死亡中的调节机制。在梗死心脏组织和暴露于铁死亡诱导剂的心肌细胞中，CRAMP水平均降低。CRAMP的过表达或LL-37预处理可减轻心肌细胞铁死亡，而CRAMP敲低则加剧细胞死亡。在铁死亡应激下，CTSL的表达升高。CRAMP通过拮抗CTSL活性抑制铁死亡。CTSL活性和水平的异常增加导致PDIA4减少。PDIA4的过表达抑制了CTSL诱导的铁死亡，而敲低PDIA4则抵消了CRAMP的保护作用。在体内，CRAMP过表达和给予CRAMP肽均显著改善心肌损伤并改善心脏功能。CRAMP通过抑制CTSL的活性增加PDIA4水平，并拮抗心肌细胞中的铁死亡。靶向CRAMP为心肌损伤的预防和管理提供了创新的治疗策略和见解。
