Adenosine and Oxygen Modulate Antimicrobial Defenses

描述(由申请人提供)：由于脓毒症的高发病率和死亡率，降低该疾病死亡率的治疗方法仍需开发。我们有强有力的初步数据表明，局部组织缺氧加上细胞外腺苷的增加，抑制了细胞清除细菌的能力。未能适当地控制细菌会导致过度和长期的炎症。该提案将评估2种不同的治疗脓毒症的方法：1)阻断特定的腺苷受体；2)补充氧气。为了增加研究结果的适用性，我们将研究4种不同的小鼠脓毒症模型。第一种模式是盲肠结扎和穿刺术(CLP)后前四天出现的急性期脓毒症，第二种模式是慢性脓毒症阶段，死亡发生在第五天之后。第三个脓毒症模型评估了创伤(腹部切开)加假单胞菌肺炎模型的治疗方式。第四个将使用最近开发的人源化的CLP诱导的脓毒症小鼠模型。我们的第一个具体目标是通过用特定的A2A和A2B受体拮抗剂治疗脓毒症小鼠来密切研究腺苷在脓毒症中的作用。我们将使用A2A和A2B受体敲除小鼠来证实这些发现的特异性。还将采用一种新的方法，使用生物标记物直接阻断腺苷受体。第二个目标将验证脓毒症期间是否发生局部缺氧，并提供补充氧气以改善预后。第三个目标是将腺苷受体阻断与补充氧气相结合，以确定这些治疗的潜在协同作用。第四个具体目标将密切研究这些治疗策略如何通过确定导致细菌清除改善的增强途径来改善结果的细胞机制。如果成功，这项应用为脓毒症提供了新的治疗策略，并提供了了解它们为什么有效的机制知识。

DESCRIPTION (provided by applicant): Therapies to reduce the mortality of sepsis still need to be developed due to the high morbidity and mortality of the disease. We have strong preliminary data indicating that local tissue hypoxia coupled with an increase in extracellular adenosine suppresses the ability of cells to eradicate bacteria. Failure to appropriately control bacteria results in excessive and prolonged inflammation. This proposal will evaluate 2 different modalities to treat sepsis by 1) blocking specific adenosine receptors and 2) providing supplemental oxygen. To increase the applicability of the findings, 4 different murine sepsis models will be studied. The first model is the acute phase of sepsis present in the first four days after cecal ligation and puncture (CLP) and the second model is the chronic phase of sepsis where deaths occur after day five. The third sepsis model evaluates the treatment modalities in a model of trauma (abdominal incision) plus Pseudomonas pneumonia. The fourth will use the recently developed humanized mouse model of sepsis induced by CLP. Our first specific aim will closely study the role of adenosine in sepsis by treating septic mice with specific A2A and A2B receptor antagonists. We will confirm the specificity of these findings using A2A and A2B receptor knockout mice. A novel approach of using biomarkers to direct blockade of the adenosine receptors will also be employed. The second aim will verify that local hypoxia occurs during sepsis and provide supplemental oxygen to improve outcome. The third aim will combine adenosine receptor blockade with supplemental oxygen to determine the potential synergistic interactions of the treatments. The fourth specific aim will closely examine the cellular mechanisms of how these treatment strategies improve outcome by determining the augmented pathways that result in improved bacterial clearance. If successful, this application offers both new treatment strategies for sepsis, and the mechanistic knowledge to understand why they are effective.