CELLULAR MECHANISMS OF OTOTOXICITY

该项目的主要目标是阐明氨基糖苷类抗生素在感觉毛细胞中的摄取和细胞内转运途径，并探讨新生毛细胞对氨基糖苷类抗生素毒性产生抗性的机制。该建议的具体目标包括：(L)测定参与受体介导的氨基糖苷类内吞作用的质膜组件；(2)评估微管在氨基糖苷类抗生素溶酶体靶向中的作用；(3)评估氨基糖苷类药物的细胞蓄积与溶酶体破裂的关系；(4)确定再生毛细胞中导致氨基糖苷类药物耐药的细胞位置。形态测量将从鸡内耳的体外和体内准备中获得。药理试剂将应用于体外制剂中，选择性地抑制细胞器的生理功能。这项研究的结果将为清楚了解氨基糖苷类药物对毛细胞的毒性的细胞/分子机制提供有价值的信息。此外，对药物摄取途径的有效操作的知识，如果与强大的细胞/分子生物学技术相结合，将使我们能够开发出新的程序，使成熟的感觉毛细胞在未来具有耐药性。

The primary goals of this project are to elucidate the uptake and intracellular transport pathways of aminoglycoside antibiotics in sensory hair cells and to investigate the mechanisms underlying resistance of newly regenerated hair cells to aminoglycoside toxicity. Specific aims in this proposal include: (l) Determination of the plasma membrane assembly involved in receptor-mediated endocytosis of aminoglycosides; (2) Evaluation of the role of microtubules in lysosomal targeting of aminoglycosides; (3) Evaluation of the relationship between cellular accumulation of aminoglycosides and lysosomal rupture; (4) Determination of the cellular site responsible for aminoglycoside resistance in the regenerated hair cells. Morphological measures will be obtained from both in vitro and in vivo preparations of the chick inner ear. Pharmacological reagents will be applied in in vitro preparations to selectively inhibit physiological functions of cellular organelles. Results obtained from this study will provide valuable information for a clear understanding of cellular/molecular mechanisms of aminoglycoside toxicity in the hair cells. In addition, knowledge of effective manipulation of the drug uptake pathways, if combined with powerful cellular/molecular biological techniques, would enable us to develop novel procedures for conferring mature sensory hair cells with drug resistance in the future.