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高死亡率，仍然需要开发降低脓毒症死亡率的治疗方法。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根除细菌的能力。如果不能适当地控制细菌，就会导致过度和长期的炎症。本提案将评估两种不同的治疗脓毒症的方式：1)阻断特异性腺苷受体和2)提供补充氧气。为了增加研究结果的适用性，我们将对4种不同的小鼠脓毒症模型进行研究。第一个模型是盲肠结扎和穿刺（CLP）后头4天出现的急性期脓毒症，第二个模型是慢性脓毒症，第5天之后发生死亡。第三个脓毒症模型评估创伤（腹部切口）加假单胞菌肺炎模型的治疗方式。第四项实验将使用新近开发的CLP致脓毒症人源化小鼠模型。我们的第一个具体目标是通过使用特异性A2A和A2B受体拮抗剂治疗脓毒症小鼠，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。一种使用生物标志物直接阻断腺苷受体的新方法也将被采用。第二个目的是验证败血症期间发生的局部缺氧，并提供补充氧气以改善结果。第三个目标将结合腺苷受体阻断和补充氧来确定治疗的潜在协同相互作用。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，这一应用将为脓毒症提供新的治疗策略，并为理解它们为何有效提供机制知识。

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. PUBLIC HEALTH RELEVANCE: The project will try and find new ways to treat severe bacterial infections. We believe that providing a small amount of oxygen and blocking receptors on cells will help these cells kill the bacteria.