Endogenous Modulation of Cochlear Injury

描述（由申请人提供）：顺铂是当前化疗方案的关键组成部分。不幸的是，顺铂经常引起双侧和不可逆的耳毒性。这对于听力损失严重阻碍语言、认知和社会发展的幼儿来说尤其具有挑战性。因此，迫切需要新的药物来降低顺铂的耳毒性。我们实验室最近的研究表明，单次经鼓室注射辣椒素（TRPV1激动剂）会导致短暂性听力损失和炎症细胞因子的暂时增加。令人惊讶的是，经鼓膜辣椒素预处理可减轻顺铂耳毒性。初步数据显示，口服辣椒素还能降低顺铂诱导的听性脑干反应（ABER）阈值偏移。我们的体外研究表明辣椒素的“预处理”效应是由瞬时STAT1上调引起的。辣椒素激活STAT1可能会修饰或隔离STAT1，从而在耳蜗细胞随后受到顺铂攻击时阻止其与p53的相互作用。另外，与顺铂不同，辣椒素可以激活STAT1（即增加其磷酸化）。辣椒素还可以激活细胞保护性STAT蛋白（如STAT3）。辣椒素还可以增加耳蜗中大麻素（CB）的表达，这可以起到细胞保护作用。在UB/OC1细胞中的初步实验表明，辣椒素上调了这些细胞中的CB受体。目的1的实验将证实口服辣椒素对顺铂耳毒性的作用，随后的3个目的将阐明其保护机制。目的2将确定辣椒素介导的抗顺铂耳毒性保护的分子基础。假设是辣椒素激活STAT1（通过介导Ser727和Tyr701磷酸化），从而隔离（或下调）STAT1，从而降低顺铂可激活的STAT1的可用性。目的3将验证辣椒素通过激活或增加耳蜗中CB受体的表达而介导的顺铂耳毒性保护的假设。在体外实验中，CB激活降低顺铂耳毒性，并在许多报道中显示出抗炎和神经保护作用。目的4将验证基因阵列将证明大鼠耳蜗中辣椒素、顺铂和顺铂加辣椒素治疗后感兴趣的基因发生变化的假设。目的5将确定辣椒素是否干扰或实际上增强顺铂的抗肿瘤疗效。该研究将为改善顺铂耳毒性提供新的保护性口服治疗提供巨大的希望。

DESCRIPTION (provided by applicant): Cisplatin is a critical component of current chemotherapy regimens. Unfortunately, cisplatin frequently causes ototoxicity that is bilateral and irreversible. This is particularly challenging in young children in whom hearing loss severely hampers speech, cognitive and social development. Thus, there is an urgent need for new drugs to reduce cisplatin ototoxicity. Recent studies from our laboratory have shown that a single transtympanic injection of capsaicin (TRPV1 agonist) produced transient hearing loss and temporary increases in inflammatory cytokines. Surprisingly, pretreatment with transtympanic capsaicin alleviated cisplatin ototoxicity. Preliminary data show that oral capsaicin also reduces cisplatin-induced auditory brain stem response (ABER) threshold shifts. Our in vitro studies suggest that capsaicin's "preconditioning" effect results from transient STAT1 up-regulation. Activation of STAT1 by capsaicin may modify or sequester STAT1, preventing its interaction with p53 when cochlear cells are subsequently challenged by cisplatin. Alternatively, capsaicin could activate STAT1 (i.e. increase its phosphorylation) differently from cisplatin. Capsaicin could also activate cytoprotective STAT proteins (such as STAT3). Capsaicin can also increase cannabinoid (CB) expression in the cochlea, which can be cytoprotective. Preliminary experiments in UB/OC1 cells show that capsaicin up-regulates CB receptors in these cells. Experiments in aim1 should confirm the efficacy of oral capsaicin against cisplatin ototoxicity and the subsequent 3 aims will elucidate mechanisms of protection. Aim 2 will determine the molecular basis of capsaicin-mediated protection against cisplatin ototoxicity. The hypothesis is that capsaicin activates STAT1 (by mediating Ser727 and Tyr701 phosphorylation) which sequesters (or down-regulates) it, thereby decreasing the availability of STAT1 accessible for activation by cisplatin. Aim 3 will test the hypothesis that capsaicin-mediated protection against cisplatin ototoxicity by activation, or increasing the expression, of CB receptors in the cochlea. CB activation reduces cisplatin ototoxicity in vitro and has demonstrated anti-inflammatory and neuroprotective effects in numerous reports. Aim 4 will test the hypothesis that Gene Array will demonstrate changes in genes of interest in the cochlea of rats treated with capsaicin, cisplatin and cisplatin plus capsaicin. Aim 5 will determine whether capsaicin interferes with or actually enhances the antitumor efficacy of cisplatin. This research will offer great promise to provide novel protective oral treatments to ameliorate cisplatin ototoxicity.