Hearing loss is a major health concern in our society, affecting more than 400 million people worldwide. Among the causes, aminoglycoside therapy can result in permanent hearing loss in 40% to 60% of patients receiving treatment, and despite these high numbers, no drug for preventing or treating this type of hearing loss has yet been approved by the US Food and Drug Administration. We have previously conducted high-throughput screenings of bioactive compounds, using zebrafish as our discovery platform, and identified piplartine as a potential therapeutic molecule. In the present study, we expanded this work and characterized piplartine’s physicochemical and therapeutic properties. We showed that piplartine had a wide therapeutic window and neither induced nephrotoxicity in vivo in zebrafish nor interfered with aminoglycoside antibacterial activity. In addition, a fluorescence-based assay demonstrated that piplartine did not inhibit cytochrome C activity in microsomes. Coadministration of piplartine protected from kanamycin-induced hair cell loss in zebrafish and protected hearing function, outer hair cells, and presynaptic ribbons in a mouse model of kanamycin ototoxicity. Last, we investigated piplartine’s mechanism of action by phospho-omics, immunoblotting, immunohistochemistry, and molecular dynamics experiments. We found an up-regulation of AKT1 signaling in the cochleas of mice cotreated with piplartine. Piplartine treatment normalized kanamycin-induced up-regulation of TRPV1 expression and modulated the gating properties of this receptor. Because aminoglycoside entrance to the inner ear is, in part, mediated by TRPV1, these results suggested that by regulating TRPV1 expression, piplartine blocked aminoglycoside’s entrance, thereby preventing the long-term deleterious effects of aminoglycoside accumulation in the inner ear compartment.

中文翻译：

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Piplartine 可减弱氨基糖苷类药物诱导的 TRPV1 活性并防止小鼠听力损失


听力损失是我们社会的一个主要健康问题，影响着全球超过 4 亿人。其中，氨基糖苷类疗法可导致 40% 至 60% 接受治疗的患者出现永久性听力损失，尽管数量如此之多，但美国食品和药物管理局尚未批准用于预防或治疗此类听力损失的药物行政。我们之前使用斑马鱼作为我们的发现平台，对生物活性化合物进行了高通量筛选，并将 piplartine 确定为潜在的治疗分子。在本研究中，我们扩展了这项工作并表征了 piplartine 的理化和治疗特性。我们发现匹拉汀具有较宽的治疗窗，既不会在斑马鱼体内引起肾毒性，也不会干扰氨基糖苷类抗菌活性。此外，基于荧光的测定表明 piplartine 不会抑制微粒体中细胞色素 C 的活性。联合给予哌普拉汀可以保护斑马鱼免受卡那霉素诱导的毛细胞损失，并保护卡那霉素耳毒性小鼠模型的听力功能、外毛细胞和突触前带。最后，我们通过磷酸组学、免疫印迹、免疫组织化学和分子动力学实验研究了匹拉汀的作用机制。我们发现用哌普拉汀联合治疗的小鼠耳蜗中 AKT1 信号传导上调。 Piplartine 治疗使卡那霉素诱导的 TRPV1 表达上调正常化，并调节该受体的门控特性。 由于氨基糖苷类药物进入内耳部分是由 TRPV1 介导的，因此这些结果表明，通过调节 TRPV1 表达，匹拉汀可阻断氨基糖苷类药物的进入，从而防止氨基糖苷类药物在内耳室中积累的长期有害影响。