PJ34 protects hair cells from cisplatin‐induced ototoxicity in vitro: possible relation to inhibition of PARP-1-AIF-mediated parthanatos

PARP inhibitor PJ34 exerts anti-inflammatory and neuroprotective effects by regulating parthanatos. The objective of this study was to investigate the protective effects of PJ34 on auditory cells against cisplatin-induced injury as well as to explore the potential mechanisms involved in its action. Flow cytometry, immunofluorescence staining, Western blot, Mitochondrial membrane potential (MMP) assay and MitoSox red staining were employed to detect apoptosis, determine the expression levels of cleaved caspase-3, PARP-1, and AIF, measure MMP levels, and evaluate the levels of reactive oxygen species (ROS) in the corresponding HEI-OC1 auditory cells, ovarian cancer cell lines, and mouse cochlear hair cells. Our results demonstrated that exposure to 30 μM cisplatin activated cleaved caspase-3, PARP-1, and induced AIF nuclear translocation, leading to a decrease in MMP and an increase in ROS levels, which induced auditory cell death. Treatment with 2.5 μM PJ34 attenuated the hyperactivation of PARP-1 and nuclear translocation of AIF after cisplatin exposure, rescued the reduction of MMP and ROS accumulation, and thus protected auditory cells from cisplatin-induced cellular damage. Furthermore, PJ34 enhanced the sensitivity of ovarian cancer cell lines to cisplatin treatment. In conclusion, our findings suggest that PJ34 may attenuate cisplatin-induced hair cell death by regulating PARP-1-mediated parthanatos. Interestingly, PJ34 shows promise as a potential novel therapeutic agent for the prevention and/or treatment of cisplatin-induced ototoxicity.

PARP 抑制剂 PJ34 通过调节细胞焦亡蛋白（parthanatos）发挥抗炎和神经保护作用。本研究旨在探讨 PJ34 对听细胞抵御顺铂诱导损伤的保护作用，并探索其作用机制。本研究采用了流式细胞术、免疫荧光染色、蛋白质印迹、线粒体膜电位（MMP）测定和 MitoSox 红染色技术，以检测细胞凋亡、确定裂解的 caspase-3、PARP-1 和 AIF 的表达水平、测量 MMP 水平，并评估 HEI-OC1 听觉细胞、卵巢癌细胞系和鼠耳蜗毛细胞的活性氧（ROS）水平。研究结果表明，30 μM 顺铂暴露激活了裂解的 caspase-3、PARP-1，并诱导 AIF 核移位，导致 MMP 水平降低和 ROS 水平升高，从而引发听觉细胞死亡。2.5 μM PJ34 处理减弱了顺铂暴露后 PARP-1 的过度激活和 AIF 的核移位，挽救了 MMP 的减少和 ROS 的积累，从而保护听觉细胞免受顺铂诱导的细胞损伤。此外，PJ34 增强了卵巢癌细胞系对顺铂治疗的敏感性。综上所述，我们的研究结果表明，PJ34 可能通过调节 PARP-1 介导的细胞焦亡蛋白来减轻顺铂诱导的毛细胞死亡。有趣的是，PJ34 作为一种新型治疗剂，在预防和/或治疗顺铂诱导的耳毒性方面展现出良好的前景。