Novel Therapies for Chlorine-Induced Lung Injury

描述(由申请人提供)：急性高水平暴露于损害呼吸道的化学物质可导致危及生命的肺损伤。氯气是一种剧毒的呼吸道刺激物，吸入后会导致细胞损伤、肺泡-毛细血管屏障破坏、炎症和肺水肿。我们正在研究G蛋白调节肺损伤、炎症和修复的机制，G蛋白是普遍存在的细胞内信号分子。在拟议的研究过程中，我们将调查G蛋白介导的信号通路如何调节当肺或肺细胞暴露在氯气中时所引起的损伤和炎症。然后，我们将应用从这些研究中获得的信息来开发基于G蛋白功能调节的新治疗策略，以改善急性肺损伤。G蛋白偶联受体(GPCRs)控制细胞内稳态和对环境刺激的反应，由组织损伤后释放的各种神经肽、炎症介质和激素激活。GPCRs通过刺激G蛋白激活细胞内信号通路，G蛋白分为四个家族：GQ、Gs、GJ和GI2。我们观察到，肺上皮细胞中GQ的激活刺激了促炎基因的表达，而Gs的激活则促进了损伤后的存活。在拟议的实验中，我们将利用GQ和Gs信号通路的操纵作为治疗氯气吸入所致急性肺损伤的潜在治疗措施。在具体目标1中，我们将研究GQ信号促进促炎转录因子NF-KB激活的机制，以及Gs抑制培养上皮细胞和内皮细胞氯毒的机制。在具体目标2中，我们将使用可诱导的、细胞特异性的基因敲除小鼠模型，确定肺上皮细胞中的GQ信号是否是改善急性肺损伤的治疗靶点。在具体目标3中，我们将在抑制GQ功能的基础上，开发包括细胞可溶性GQ抑制肽和GQ siRNA在内的氯致肺损伤的治疗策略。在具体目标4中，我们将基于对GQ功能的抑制和Gs下游的刺激信号通路，优化氯致肺损伤治疗药物的体内给药。本申请是根据RFA-NS-06-004《应对化学威胁的对策》提交的。拟议的实验旨在了解吸入有毒化学物质如何损害肺部，并根据这些信息开发治疗或预防急性肺损伤的新方法。这种类型的研究是通过RFA寻求的，因为担心美国平民可能会受到在恐怖袭击中故意释放的剧毒化学品或在工业事故或自然灾害中无意释放的高度有毒化学品的不利影响。

DESCRIPTION (provided by applicant): Acute high-level exposures to chemicals that damage the respiratory tract can cause life-threatening lung injury. Chlorine gas is a highly toxic respiratory irritant that when inhaled causes cellular injury, alveolar- capillary barrier disruption, inflammation, and pulmonary edema. We are investigating mechanisms by which G proteins, which are ubiquitous intracellular signaling molecules, regulate lung injury, inflammation, and repair. During the course of the proposed research we will investigate how G protein-mediated signaling pathways regulate injury and inflammation that are induced when lungs, or lung cells, are exposed to chlorine gas. We will then apply the information gained from these studies to develop novel treatment strategies based on modulation of G protein function to ameliorate acute lung injury. G protein coupled receptors (GPCRs), which control cellular homeostasis and responses to environmental stimuli, are activated by a variety of neuropeptides, inflammatory mediators, and hormones that are released following tissue injury. GPCRs activate intracellular signaling pathways by stimulating G proteins that have been classified into four families: Gq, Gs, Gj, and Gi2. We have observed that activation of Gq in lung epithelial cells stimulates proinflammatory gene expression, whereas activation of Gs promotes increased survival following injury. In the proposed experiments, we will use manipulation of Gq and Gs signaling pathways as potential therapeutic measures to treat acute lung injury induced by inhalation of chlorine gas. In Specific Aim 1 we will examine mechanisms by which Gq signaling promotes activation of the proinflammatory transcription factor NF-KB and Gs inhibits chlorine toxicity in cultured epithelial and endothelial cells. In Specific Aim 2, we will determine, using an inducible, cell-specific knockout mouse model, whether Gq signaling in lung epithelial cells is a therapeutic target for ameliorating acute lung injury. In Specific Aim 3, we will develop treatment strategies, including cell-soluble Gq inhibitory peptides and Gq siRNA, for chlorine-induced lung injury based on inhibition of Gq function. In Specific Aim 4, we will optimize the in vivo delivery of therapeutic agents for chlorine-induced lung injury based on inhibition of Gq function and stimulation signaling pathways downstream of Gs. This application is submitted in response to RFA-NS-06-004, "Countermeasures Against Chemical Threats." The proposed experiments are designed to understand how inhalation of a toxic chemical injures the lung and, based on this information, to develop novel ways to treat or prevent acute lung injury. This type of research is sought through the RFA because of concerns that U. S. civilians could be adversely affected by highly toxic chemicals released intentionally in terrorist attacks or unintentionally in industrial accidents or natural disasters.