RESUMO
Cisplatin-induced hearing loss is a common side effect of cisplatin chemotherapy, for which clinical therapy remains unavailable. Apoptosis of hair cells is considered the primary cause of cisplatin-induced ototoxicity; however, inhibiting apoptosis can only partially restore cisplatin-induced hearing loss. Therefore, auditory cell death caused by cisplatin damage requires further study. Ferroptosis, a novel form of regulated cell death, has been shown to play a role in the mechanism of cisplatin toxicity. In this study, we observed proferroptotic alterations (lipid peroxidation and impaired antioxidant capacity) in the cochleae of C57BL/6 mice after cisplatin damage, verifying the induction of ferroptosis. Using the HEI-OC1 cell line, we observed that cisplatin induced proferroptotic alterations and activated ferritinophagy (specific autophagy pathway). Employing chloroquine, we confirmed that the blockage of autophagy remarkably alleviated cisplatin-induced ferroptosis in HEI-OC1 cells; therefore, the induction of ferroptosis in cisplatin-treated auditory cells was dependent on the activation of autophagy. In addition, the ferroptosis inhibitor ferrostatin-1 and iron chelator deferoxamine significantly attenuated cisplatin-induced cytotoxicity in HEI-OC1 cells and cochlear explants. Moreover, pharmacologically inhibiting ferroptosis using ferrostatin-1 significantly decreased the auditory cell loss and, notably, attenuated hearing loss in C57BL/6 mice after cisplatin damage. Collectively, these findings indicate that autophagy-dependent ferroptosis plays an integrated role in the mechanism of cisplatin-induced hearing loss.
Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Cisplatino/toxicidade , Ferroptose/efeitos dos fármacos , Células Ciliadas Auditivas/efeitos dos fármacos , Perda Auditiva/induzido quimicamente , Ototoxicidade/etiologia , Animais , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos AnimaisRESUMO
Cisplatin, the most widely used platinum-based anticancer drug, often causes progressive and irreversible sensorineural hearing loss in cancer patients. However, the precise mechanism underlying cisplatin-associated ototoxicity is still unclear. Nicotinamide adenine dinucleotide (NAD+), a co-substrate for the sirtuin family and PARPs, has emerged as a potent therapeutic molecular target in various diseases. In our investigates, we observed that NAD+ level was changed in the cochlear explants of mice treated with cisplatin. Supplementation of a specific inhibitor (TES-1025) of α-amino-ß-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD), a rate-limiting enzyme of NAD+de novo synthesis pathway, promoted SIRT1 activity, increased mtDNA contents and enhanced AMPK expression, thus significantly reducing hair cells loss and deformation. The protection was blocked by EX527, a specific SIRT1 inhibitor. Meanwhile, the use of NMN, a precursor of NAD+ salvage synthesis pathway, had shown beneficial effect on hair cell under cisplatin administration, effectively suppressing PARP1. In vivo experiments confirmed the hair cell protection of NAD+ modulators in cisplatin treated mice and zebrafish. In conclusion, we demonstrated that modulation of NAD+ biosynthesis via the de novo synthesis pathway and the salvage synthesis pathway could both prevent ototoxicity of cisplatin. These results suggested that direct modulation of cellular NAD+ levels could be a promising therapeutic approach for protection of hearing from cisplatin-induced ototoxicity.
Assuntos
Inibidores Enzimáticos/farmacologia , Células Ciliadas Auditivas/efeitos dos fármacos , Perda Auditiva/prevenção & controle , Audição/efeitos dos fármacos , NAD/biossíntese , Ototoxicidade/prevenção & controle , Sirtuína 1/metabolismo , Animais , Animais Geneticamente Modificados , Carboxiliases/antagonistas & inibidores , Carboxiliases/metabolismo , Cisplatino , Modelos Animais de Doenças , Ativação Enzimática , Células Ciliadas Auditivas/enzimologia , Células Ciliadas Auditivas/patologia , Perda Auditiva/induzido quimicamente , Perda Auditiva/enzimologia , Perda Auditiva/fisiopatologia , Sistema da Linha Lateral/efeitos dos fármacos , Sistema da Linha Lateral/enzimologia , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , Mitocôndrias/patologia , Ototoxicidade/enzimologia , Ototoxicidade/etiologia , Ototoxicidade/fisiopatologia , Peixe-ZebraRESUMO
Cisplatin is a well-known and commonly used chemotherapeutic agent. However, cisplatin-induced ototoxicity limits its clinical use. Previous studies have shown an important role of reactive oxygen species (ROS) accumulation in the pathogenesis of cisplatin-induced ototoxicity. In many cell types, the transcription factor, nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant response element (ARE) protect against oxidative stress by suppressing ROS. Here our results showed that cisplatin injury reduced Nrf2 expression and inhibited Nrf2 translocation in HEI-OC1 cells and Nrf2 activator tert-butylhydroquinone (TBHQ) rescued hair cells from cisplatin induced apoptosis by suppressing the total cellular ROS accumulation. Moreover, we found that decreased ROS accumulation induced by TBHQ didn't depend on mitochondrial derived ROS production, indicating that Nrf2 activation alleviated cisplatin induced oxidative stress and apoptosis through mitochondrial-independent ROS production. Therefore, we provide a potential strategy of prevention and treatment for cisplatin-induced ototoxicity by Nrf2 activation. In conclusion, Nrf2 activation protects auditory hair cells from cisplatin-induced ototoxicity through suppressing the total cellular ROS levels which arise from sources other than mitochondria.