Mechanisms of Cochlear Oxidative Stress Injury and Strategies to Protect Hearing

描述(由申请者提供)：这个职业发展奖的目标是在听觉研究方面建立一个富有成效的研究计划，将促进我过渡到耳鼻喉科的独立临床医生和科学家。这一培训计划包括一个由外部咨询委员会指导的有指导的研究计划和有组织的职业提升活动。综合导师团队包括伦纳德·雷巴克医学博士担任导师，维克拉姆·拉姆库马尔博士和凯瑟琳·坎贝尔博士担任共同导师。这一奖项将为以患者为导向的科学研究领域的可持续职业生涯奠定基础。实验工作的重点是庆大霉素(一种氨基糖苷类原型)治疗后对内耳造成氧化应激损伤的分子机制。氨基糖苷类抗生素在治疗危及生命的感染中仍然发挥着重要作用，但它们也与永久性双侧听力损失以及平衡障碍、耳鸣和肾毒性有关。作为一名耳鼻喉科医生，我照顾患有各种疾病的儿童和成年人，这些疾病会影响他们有效地表达自己或在社会中发挥最佳功能的能力。对于那些听力损失的患者，我 可以看到沟通障碍对他们生活的深远影响。我长期致力于将实验室的发现带到床边，这为这个转化研究项目提供了动力。该研究策略强调氧化应激的作用，基于先前的研究表明，活性氧物种导致药物诱导和噪声诱导的听力损失，抑制这些活性氧物种可能提供耳保护。不同类型的对耳朵的侮辱可能会聚集在共同的分子途径上，导致耳蜗炎，并最终导致毛细胞死亡。这项研究计划的中心假设是，对氧化应激进行有针对性的干预可以减轻耳蜗炎，从而降低庆大霉素对内耳造成损伤的风险。使用有针对性的方法也可能降低严重副作用的风险。这项为期五年的研究计划包括一系列相关实验，以探讨庆大霉素的耳毒性机制，以及反铂作为潜在的耳保护剂的作用。转铂是顺铂的一种不活跃的反式异构体，它可以减少与药物引起的听力损失有关的几个关键分子的表达。通过经鼓室或全身途径给药，将在动物模型中确定反铂保护的剂量-反应效应。评估将通过扫描电子显微镜、听觉脑干反应测试和免疫组织化学分析进行。在耳蜗源性细胞系中的实验将研究转铂如何调节耳蜗内的氧化应激、基因表达和炎症。这项工作将更好地确定细胞膜通道、转录因子和其他分子靶标在庆大霉素引起的听力损失中的作用。这项研究的长期目标是开发安全有效的策略来预防与氨基糖苷类抗生素治疗相关的听力损失。

DESCRIPTION (provided by applicant): The goal of this career development award is to establish a productive research program in auditory research that will foster my transition to an independent clinician-scientist in otolaryngology. This training program comprises a mentored research plan with guidance by an external advisory committee and structured career-enhancing activities. The integrated mentoring team includes Leonard Rybak, M.D.,Ph.D. as mentor and Vickram Ramkumar, Ph.D., and Kathleen Campbell, Ph.D. as co-mentors. This award will lay the groundwork for a sustainable career in patient-directed scientific investigation The experimental work focuses on the molecular mechanisms responsible for oxidative stress injury to the inner ear after treatment with gentamicin, a prototype aminoglycoside. Aminoglycoside antibiotics continue to have an essential role in the treatment of life-threatening infections, but they are also associated with a risk of permanent, bilateral hearing loss, as well as balance disturbance, tinnitus, and nephrotoxicity. As an otolaryngologist, I care for children and adults suffering from a broad range of disorders that affect their ability to express themselves effectively or to function optimally in society. For those patients with hearing loss, I can see the far-reaching effects of impaired communication on their lives. My longstanding commitment to taking findings in the laboratory and bringing them to the bedside provides the impetus for this translational research program. The research strategy emphasizes the role of oxidative stress based on prior studies showing that reactive oxygen species contribute to drug-induced and noise-induced hearing loss and that dampening these reactive oxygen species may confer otoprotection. Different types of insults to the ear may converge on common molecular pathways to cause cochlear inflammation and ultimately hair cell death. The central hypothesis of this research plan is that targeted interference with oxidative stress can attenuate cochlear inflammation and in doing so decrease the risk of gentamicin-induced injury to the inner ear. Use of a targeted approach may also decrease the risk of serious side effects. The five-year research plan involves a series of related experiments that investigate the mechanisms of gentamicin ototoxicity and the role of transplatin as a potential otoprotectant. Transplatin is an inactive trans-isomer of cisplatin that reduces expression of several key molecules involved in drug-induced hearing loss. A dose-response effect for transplatin protection will be determined in an animal model by delivering transplatin via transtympanic or systemic routes. Assessments will be made by scanning electron microscopy, auditory brainstem response testing, and immunohistochemical assays. Experiments in cochlea-derived cell lines will investigate how transplatin modulates oxidative stress, gene expression, and inflammation in the cochlea. This work will better define the role of cell membrane channels, transcription factors, and other molecular targets in gentamicin-induced hearing loss. The long-term goal of this research is to develop safe and effective strategies to prevent hearing loss related to aminoglycoside antibiotic therapy.