Developing Non-Ototoxic Aminoglycosides

说明(申请人提供)：氨基糖苷类(AGs)抗生素因其强大的抗菌活性和低成本而在全球范围内使用。尽管它们有明显的耳毒性和肾毒性副作用，但仍被广泛使用。来自独立实验室的最新证据表明，由于AGs能够通过位于立体纤毛顶端附近的机电换能器通道进入毛细胞，因此AGs在毛细胞中迅速积累。通道生物物理特性促进了通道的进入，但限制了通过这些相同通道的出口。我们的数据清楚地表明，通过这些渠道阻断进入可以预防耳毒性。这项建议的目标是开发新的无耳毒性氨基糖苷类药物。我们的团队对机械门控通道的生物物理特性有独特的见解，并可以利用这些知识来设计在空间和/或电气上受到限制的化合物，使其无法进入通道并因此进入毛细胞。在AG主干上选择用于修饰的位置，以便不干扰抗菌活性。我们有能力在通道、细胞、终末器官、系统和整个动物水平上研究这些化合物，使用电生理、光学、分子和药理学手段来监测耳毒性和抗菌活性。对这些化合物的发展的补充将是确定AGs进入内淋巴室的机制。一旦确定了这一途径，我们将设计出限制现有AG运输的方法，以便共同治疗计划可能阻止AG进入MET通道，从而限制进入毛细胞。这项建议的重点是设计治疗方案，要么通过创造新的AGG，要么通过共同治疗计划，以减轻由于AG给药造成的耳毒性。在拟议的两年研究期结束时，我们将应用我们独特的知识库和技能集来深入了解这两种方法中的任何一种在减少由AGs引起的耳毒性方面的有效性。 公共卫生相关性：氨基糖苷类(AGs)是全世界使用最广泛的抗生素，尽管其耳毒性发生率很高。我们已经证明，听觉毛细胞对AGs的敏感性是因为它们对AG的摄取率很高，这源于AGs通过位于立体纤毛顶端的一种新的机械敏感离子通道的能力。我们的计划是设计新的抗生素，这些抗生素在灭菌和/或电气上受到限制，不能通过这一通道。结合这一方法，我们将确定AG进入内淋巴溶液的机制，并设计一个共同治疗计划来阻止负责的运输机制，从而防止AG到达它们渗透的离子通道。

DESCRIPTION (provided by applicant): Aminoglycoside (AGs) antibiotics are used worldwide because of their potent antimicrobial activities and low cost. They are widely used despite the significant side effects of ototoxicity and nephrotoxicity. Recent evidence from independent laboratories demonstrated that AGs accumulate rapidly in hair cells because of their ability to enter these cells through the mechanoelectric transducer channel located near the tops of the stereocilia. Channel biophysical properties promote entry through the channel but limit exit through these same channels. Our data clearly show that ototoxicity can be prevented by blocking entry via these channels. The goal of this proposal is to develop novel non-ototoxic aminoglycosides. Our team has unique insights into the biophysical properties of the mechanically gated channels and can use this knowledge to design compounds that are sterically and/or electrically restricted from entering the channel and therefore the hair cell. Sites for modification are selected on the AG backbone so as not to interfere with antimicrobial activity. We have in hand the ability to investigate these compounds at the channel, cellular, end organ, system and whole animal level, using electrophysiological, optical, molecular and pharmacological means to monitor ototoxicity as well as antimicrobial activity. Complementary to the development of these compounds will be identifying the mechanism of entry of the AGs into the endolymph compartment. Upon identification of this pathway we will devise means to limit transport of existing AGs so that a co-treatment plan might prevent access of the AGs to the MET channel and thus limit entry into hair cells. The focus of this proposal is to design treatment regimes, either by creating novel AGs, or co-treatment plans, that will ameliorate ototoxicity due to AG administration. At the end of the proposed two-year research period, we will have applied our unique knowledge base and skill sets to gain insights into the effectiveness of either of these approaches in reducing ototoxicity caused AGs. PUBLIC HEALTH RELEVANCE: Aminoglycosides (AGs) are the most widely used antibiotics worldwide, despite having a high incidence of ototoxicity. We have shown that auditory hair cells are sensitive to AGs because of their high rate of AG uptake, arising from the ability of AGs to pass through a novel mechanosensitive ion channel located at the tops of the stereocilia. Our plan is to design new antibiotics that are sterically and/or electrically restricted from passing through this channel. In conjunction with this approach we will identify the mechanism by which AGs enter the endolymph solution and devise a cotreatment plan to block the responsible transport mechanism, thus preventing the AGs from reaching the ion channel that they permeate.