Glutathione Monoesters to Counteract Ocular Chemical Injury

 描述（由申请人提供）：该项目的目标是测试谷胱甘肽单酯（GME）可用作对抗化学战剂硫芥（SM）引起的眼部毒性的第一道防线的假设。这种起泡剂会导致严重的眼部损伤，包括眼睑烧伤、疼痛、长期结膜炎、角膜混浊、角膜溃疡，严重时甚至导致失明。氧化应激、细胞凋亡、炎症和蛋白水解是 SM 引起的组织损伤发病机制中涉及的已知机制。众所周知，SM 诱导的毒性与谷胱甘肽 (GSH) 的消耗有关，补充 GSH 或 N-乙酰半胱氨酸 (NAC) 可以预防和/或防止细胞培养实验中 SM 诱导的细胞损伤。虽然这些发现令人鼓舞，但使用 GSH 或 NAC 作为治疗方法有几个缺点，包括 GSH 和 NAC 的生物利用度有限以及 NAC 作为促氧化剂的可能性。这些固有问题大大削弱了使用 GSH 或 NAC 作为治疗剂来预防 SM 引起的眼部损伤的潜力。我们建议检验以下假设：GME 可以保护眼睛免受接触 SM 造成的伤害。谷胱甘肽单酯（其中谷胱甘肽三肽的甘氨酸羧基被酯化）已被证明是有效的谷胱甘肽递送剂。它们很容易被转运到细胞中，然后被细胞内酯酶酶切以释放 GSH。体外和体内研究表明，GME 治疗导致细胞总 GSH 水平升高，超过单独 GSH 治疗所达到的水平。因此，GME 消除了与单独使用 GSH 作为化学战剂治疗策略相关的细胞摄取挑战。该项目的具体目标是确定 GME 在治疗 SM 引起的眼组织损伤方面的功效。这将涉及使用新型离体兔眼 (IRE) 模型来测量 GME 治疗对 SM 类似物暴露后损伤深度 (DoI) 的影响。成功完成本提案中概述的实验将提供重要的可行性数据，预计这些数据将支持该项目的扩展，以检查 GME 对活体动物中 SM 的保护作用。

 DESCRIPTION (provided by applicant): The goal of this project is to test the hypothesis that glutathione monoesters (GME) can be used as a first line of defense against ocular toxicity caused by the chemical warfare agent sulfur mustard (SM). This vesicant causes severe ocular injuries, including eyelid burns, pain, prolonged conjunctivitis, corneal opacity, corneal ulceratin and, in severe cases, blindness. Oxidative stress, apoptosis, inflammation and proteolysis are among the known mechanisms involved in the pathogenesis of tissue injury induced by SM. It is well established that SM-induced toxicity is associated with depletion of glutathione (GSH) and that supplementation with either GSH or N-acetylcysteine (NAC) may prevent and/or protect against SM-induced cellular injury in cell culture experiments. While these findings are encouraging, the approach of using GSH or NAC as a treatment has several drawbacks, including the limited bioavailability of GSH and NAC as well as that the possibility of NAC acting as pro-oxidant. These inherent problems diminish substantially the potential of using either GSH or NAC as therapeutic agents for protection against ocular injury caused by SM. We propose to test the hypothesis that GME protects the eye against damage caused by exposure to SM. Monoesters of GSH, in which the glycine carboxyl group of the GSH tripeptide is esterified, have been shown to be effective GSH delivery agents. They are readily transported into cells and then enzymatically cleaved by intracellular esterases to release GSH. In vitro and in vivo studies have shown that GME treatment results in elevations in total cellular GSH levels that exceed those achieved by GSH treatment alone. Hence, GME obviates the cellular uptake challenges associated with using GSH alone as a treatment strategy for chemical warfare agents. The specific goal of this project is to determine the efficacy of GME in treating ocular tissue damage induced by SM. This will involve the use of a novel ex vivo isolated rabbit eye (IRE) model to measure the effect of GME treatment on the depth of injury (DoI) following SM analog exposure. Successful completion of the experiments outlined in this proposal will provide important feasibility data that are anticipated to support the expansion of this project to examining the protective effects of GME against SM in live animals.