Table_1_Heme Oxygenase-1 Protects Hair Cells From Gentamicin-Induced Death.DOCX

Gentamicin ototoxicity can generate free radicals within the inner ear, leading to permanent damage to sensory hair cells (HCs) and eventually hearing loss. The following study examined the alterations of oxidative damage-related genes in the cochlea and important molecules responsible for oxidation following gentamicin injury in vitro. The RT2 Profiler polymerase chain reaction (PCR) array was used to screen candidate targets for treatment to prevent hearing loss caused by gentamicin. We found that during gentamicin-induced death in HCs, Heme oxygenase-1 (HO-1) had a high fold change in the HCs of the cochlea. Moreover, the use of CoPPIX to induce HO-1 inhibited gentamicin-induced HC death, while HO-1 inhibitors ZnPPIX after CoPPIX reversed this process. Furthermore, the inhibitors of NF-E2-related factor-2 (Nrf2) reduced the expression of HO-1 and inhibited the protective effect of HO-1 after gentamicin, thus suggesting that the Nrf2/HO-1 axis might regulate gentamicin-associated ototoxicity. We further demonstrated that induction of HO-1 up-regulated the expression of Nrf2 in both cochlear and HEI-OC1 cells. In summary, these findings indicated that HO-1 protects HCs from gentamicin by up-regulating its expression in HCs and interacting with Nrf2 to inhibit reactive oxygen species (ROS).

庆大霉素耳毒性可在内耳中产生自由基，进而造成感觉毛细胞（sensory hair cells, HCs）永久性损伤，最终引发听力损失。本研究针对体外庆大霉素损伤模型，考察了耳蜗内氧化损伤相关基因与氧化应激相关重要分子的表达变化。研究采用RT2 Profiler聚合酶链式反应（PCR）阵列，筛选可用于预防庆大霉素诱导听力损失的潜在治疗靶点。我们发现，在庆大霉素诱导的HCs死亡过程中，血红素氧合酶-1（heme oxygenase-1, HO-1）在耳蜗HCs中呈现出显著的表达倍数变化。进一步实验显示，使用CoPPIX诱导HO-1表达可抑制庆大霉素诱导的HC死亡，而在CoPPIX处理后加入HO-1抑制剂ZnPPIX则可逆转该保护效应。此外，核因子E2相关因子2（NF-E2-related factor-2, Nrf2）的抑制剂可下调HO-1的表达，并阻断庆大霉素损伤后HO-1的保护作用，这提示Nrf2/HO-1信号轴可能参与调控庆大霉素相关耳毒性。本研究还进一步证实，诱导HO-1表达可同时上调耳蜗细胞与HEI-OC1细胞中Nrf2的表达。综上，本研究结果表明，HO-1可通过在HCs中上调自身表达，并与Nrf2相互作用以抑制活性氧（reactive oxygen species, ROS）的产生，从而保护HCs免受庆大霉素的损伤。