Evaluation of a peptide that inhibits the activation of NOX2 and the generation of reactive oxygen species in protection against acute lung injury

总结： 急性肺损伤（ALI）是一种毁灭性的并发症脓毒症，病毒和细菌 肺炎、严重创伤伴或不伴大量失血、酸吸入和其他 主要或继发影响肺部的疾病。这相对常见 综合征（在美国每年约200，000例）目前的总体死亡率为 ~ 40%。与活性氧产生相关的肺部炎症 (ROS)是导致ALI综合症的重要因素。我们已经证明， NADPH氧化酶，2型（NOX 2），肺中ROS的主要来源，需要PLA 2 过氧化物氧还蛋白6（Prdx 6）的活性，并且最近鉴定了一种9个氨基酸的肽 结合Prdx 6并抑制其PLA 2活性;我们将其命名为Prdx 6抑制剂 肽（PIP-2）。PIP-2包封在脂质体中并经鞘内（IT）给药 对小鼠肺内ROS生成的抑制作用>80%，持续24 h。PIP-2给药12-16 低剂量LPS（给予IT）后3 h， 在24小时检查时，氧化损伤大大降低了死亡率（从100%到100%）。 28%。PIP-2也显著降低了小鼠死亡率， 腹腔内LPS作为脓毒症模型。我们现在建议评估 PIP-2对2种感染相关性ALI小鼠模型肺损伤的影响第一个将是 肺炎克雷伯菌感染模型（Sp.Aim 1）;第二个模型为盲肠 结扎和穿刺（Sp. Aim 2）。PIP-2将在施用后12或24小时施用。 细菌的侮辱。我们将评估PIP对肺部炎症的影响， 血气屏障和氧化损伤。我们还将确定PIP对 肺细菌负荷作为NOX 2抑制剂可能干扰PMN杀菌 机制等我们认为PIP-2将在临床上应用于预防 肺部炎症和组织氧化损伤是导致 ALI的发病机制。我们计划进行第二阶段的STTR应用，以评估PIP的效果 在大型动物模型中更复杂的急性肺损伤模型的治疗， 确定肽施用的可能的毒理学作用。

SUMMARY: Acute lung injury (ALI) is a devastating complication of sepsis,viral and bacterial pneumonias, severe trauma with or without major blood loss, acid aspiration and other conditions that affect the lung either primarily or secondarily.This relatively common syndrome (~200,000 cases per yr in the US) currently has an overall mortality rate of ~40%. Lung inflammation associated with the production of reactive oxygen species (ROS) is an important contributor to the ALI syndrome. We have shown that activation of NADPH oxidase, type 2 (NOX2), the major source of ROS in lungs, requires the PLA2 activity of peroxiredoxin 6 (Prdx6) and have recently identified a 9 amino acid peptide that binds to Prdx6 and inhibits its PLA2 activity; we have named this Prdx6 inhibitory peptide (PIP-2). PIP-2 encapsulated in liposomes and administered intratracheally (IT) to mice inhibited the lung generation of ROS by >80% for 24 h. PIP-2 administered 12-16 h after low dose LPS (given IT) markedly decreased lung inflammation and tissue oxidative injury when examined at 24 h and greatly decreased mortality (from 100% to 28%) after high dose LPS. PIP-2 also markedly decreased mouse mortality after intraperitoneal LPS as a model of sepsis. We now propose to evaluate the effect of PIP-2 on lung injury in 2 mouse models of ALI associated with infection. The first will be the Klebsiella pneumoniae infection model (Sp.Aim 1); the 2nd model will be the cecal ligation and puncture (Sp. Aim 2). PIP-2 will be administered at either 12 or 24 hrs after the bacterial insult. We will evauate the effect of PIP on lung inflammation, disruption of the blood-gas barrier,and oxidative injury. We also will determine the effect of PIP on lung bacterial load as the NOX2 inhibitor may interfere with PMN bactericidal mechanisms. We propose that PIP-2 will have clinical application for the prevention of lung inflammation and tissue oxidative injury that are major contributors to the pathogenesis of ALI. We plan a phase 2 STTR application to evaluate the effect of PIP treatment on more complex models of acute lung injury in large animal models and to determine possible toxicological effects of peptide administration.