Nitrite dependent protection against Cl2 gas toxicity_role of chlorinated lipids

描述（由申请人提供）：氯（Cl2）气体介导的损伤是复杂的，涉及暴露期间发生的直接毒性和暴露后数小时至数天内对气道、肺和全身血管系统的强烈毒性。初步数据和我们最近发表的研究表明，Cl2暴露后的损伤包括一氧化氮生物利用度的显著降低，这是由肺和肺外血管中enos依赖性血管舒张的减少所指示的，并证明了Cl2暴露后单次注射亚硝酸盐（一种一氧化氮补充策略）可以防止急性肺损伤、气道高反应性和重要的死亡率。在本提案中，我们将i)建立一个治疗框架，用于开发亚硝酸盐作为可在大规模伤亡情况下使用的暴露后治疗方法。Cl2后气体损伤是如何发生的尚不清楚。我们展示了新的数据，Cl2气体增加了肺和循环氯代脂质（Cl-lip），这是一种源自等离子原的-氯脂肪酸。Cl-lip可以作为Cl2暴露的新生物标志物，但我们也提供证据表明这些物种本身可以引起急性肺损伤和气道上皮细胞功能障碍。重要的是，氯唇依赖性毒性也可以通过暴露后亚硝酸盐治疗来预防。综上所述，我们假设Cl-lip是Cl2气体毒性的新型生物标志物和介质，暴露后亚硝酸盐治疗将减轻Cl2气体和Cl-lip依赖性毒性，并将通过以下具体目的进行测试：确定Cl-lip在介导Cl2气体毒性中的作用；确定亚硝酸盐减毒致死和亚致死的最佳治疗条件

DESCRIPTION (provided by applicant): Chlorine (Cl2) gas mediated injury is complex involving a direct toxicity that occurs during the exposure and a robust post exposure toxicity that occurs over hrs-days to the airways, pulmonary and systemic vasculature. Preliminary data and our recently published studies show that injury post Cl2 exposure includes significant decreases in NO-bioavailability as indexed by diminution of eNOS-dependent vasodilation in the pulmonary and extrapulmonary vasculature and demonstration that post Cl2 exposure administration of nitrite (an NO- repleting strategy) by a single IM injection, protects against acute lung injury, airway hyper-reactivity and importantly, mortality. In this proposal we will i) establish a therapeutic framework for the development for the use of nitrite as a post exposure therapeutic that can be administered in mass casualty scenarios. How post- Cl2 gas injury occurs is unclear. We show novel data that Cl2 gas increases lung and circulating chlorinated lipids (Cl-lip), which are �-chloro fatty acids derived from plasmalogens. Cl-lip may serve as novel biomarkers for Cl2 exposure, but we also provide evidence that these species can themselves cause acute lung injury and airway epithelial cell dysfunction. Importantly, Cl-lip dependent toxicity can also be prevented by post-exposure nitrite therapy. Taken together, we hypothesize that Cl-lip are novel biomarkers and mediators of post Cl2 gas toxicity and that post-exposure nitrite therapy will attenuate Cl2 gas and Cl-lip dependent toxicity and will test this via the following Specific Aims: 1. Determine the role of Cl-lip in mediating Cl2 gas induced toxicity, 2. Determine optimal nitrite therapeutic conditions for attenuating lethal and sub-lethal Cl2 gas toxicity, 3. Determine safety / toxicology profiles for IM nitrite administration under GLP conditions. A combination of in vivo Cl2 gas exposure with ex vivo studies is proposed. We feel this research is both timely and important and anticipate will yield novel insights into molecular mechanisms of Cl2 gas toxicity and identify and develop therapeutic (countermeasure) strategies.