Analysis of ADAM10 in infection-associated MODS

项目总结 与严重感染或败血症有关的死亡与一个或多个器官的难治性衰竭有着千丝万缕的联系。 系统。虽然在理解关键的分子机制方面取得了进展，但特定的 微生物会导致严重感染，我们仍然对不同种类的人类 病原体引起定义为多器官功能障碍综合征的全身性疾病的快速进展 (MODS)。在患有败血症的儿童中，超过90%的儿童表现出多器官功能障碍，这提供了一种临床 必须了解儿童败血症引起多器官功能障碍的基本机制。随着利率的上升 了解抗菌素耐药性和MODS的难治性，更深入地了解MODS的本地化 感染转化为危及生命的系统性疾病是必要的。我们已经证明了锌的作用 依赖性金属蛋白酶在金黄色葡萄球菌和脆弱杆菌致死性感染发病机制中的作用 人类败血症的主要病原体。金黄色葡萄球菌α毒素利用宿主ADAM10(A去整合素和 金属蛋白酶10)作为其细胞受体，过早地触发金属蛋白酶的病理性激活。 脆性芽孢杆菌毒素(BFT)是一种锌依赖的金属蛋白酶，类似于ADAM10。ADAM10和BFT都是 导致致命性感染相关的多器官功能障碍。基于这些发现，我们认为与感染相关的 MODS是由宿主ADAM10的异常激活所催化的。因为ADAM10被无处不在地表达和 参与不同的宿主细胞过程，这种金属蛋白酶处于有利地位，导致范围 在多器官功能障碍综合征中观察到的损伤。因此，这项提议的主要目标是检验ADAM10的假设 在严重肺炎和血液感染引起的多器官功能障碍综合征的发展中是必需的 由关键的人类细菌和真菌病原体。这一建议基于三个发现：1)细胞类型 特异性ADAM10基因敲除小鼠可鉴定金黄色葡萄球菌α毒素对小鼠单个细胞的影响 致死性感染，揭示了这些依赖于毒素介导的ADAM10的激活和病理性切割 原生ADAM10底物。2)感染相关器官功能障碍是ADAM10作用于 离散的细胞，随着时间的推移整合到组织中。3)人类ADAM10基因的特定多态易患 导致严重脓毒症的发展，而不考虑激发病原体。扩展这些观察结果 对ADAM10在MODS中更广泛作用的体内分析将提供一个机会 检验宿主金属蛋白水解酶对多器官功能障碍综合征至关重要的创新假设。作为特异性的抑制物 ADAM10已经在人体临床试验中证明是安全的，从这些研究中获得的知识可能会使 一类治疗感染相关多器官功能障碍的新疗法的评价。

PROJECT SUMMARY Death related to severe infection, or sepsis, is inextricably linked to the refractory failure of one or more organ systems. While advances have been made in understanding key molecular mechanisms by which specific microorganisms cause severe infection, we still have a poor understanding of how a diverse array of human pathogens elicit the rapid progression of systemic disease defined as multiple organ dysfunction syndrome (MODS). Among children with sepsis, over 90% demonstrate multi-organ dysfunction, providing a clinical imperative to understand fundamental mechanisms by which pediatric sepsis causes MODS. With rising rates of antimicrobial resistance and the refractory nature of MODS, a deeper understanding of how localized infection converts to life-threatening systemic disease is needed. We have demonstrated the role of zinc dependent metalloproteases in the pathogenesis of lethal infection caused by S. aureus and B. fragilis – two leading etiologic agents of human sepsis. S. aureus α-toxin utilizes host ADAM10 (A Disintegrin and Metalloprotease 10) as its cellular receptor, triggering untimely, pathologic activation of the metalloprotease. The B. fragilis toxin (BFT) is a zinc dependent metalloprotease similar to ADAM10. ADAM10 and BFT both contribute to lethal infection-associated MODS. Based on these findings, we propose that infection-associated MODS is catalyzed by aberrant activation of host ADAM10. As ADAM10 is ubiquitously expressed and involved in diverse host cellular processes, this metalloprotease is well-positioned to cause the scope of injuries observed in MODS. The primary goal of this proposal is thus to examine the hypothesis that ADAM10 is required for the development of MODS in the setting of severe pneumonia and bloodstream infection caused by key human bacterial and fungal pathogens. This proposal is based on three discoveries: 1) Cell-type specific ADAM10 knockout mice permit the identification of effects of S. aureus α-toxin on individual cells in lethal infection, revealing that these depend on toxin-mediated activation of ADAM10 and pathologic cleavage of native ADAM10 substrates. 2) Infection-related organ dysfunction is a composite of ADAM10 action on discrete cells, integrated in the tissue over time. 3) A specific polymorphism in human ADAM10 predisposes toward the development of severe sepsis, irrespective of the inciting pathogen. Extending these observations toward the in vivo analysis of the broader role of ADAM10 in MODS as proposed will provide an opportunity to examine the innovative hypothesis that a host metalloprotease is critical for MODS. As specific inhibitors of ADAM10 have demonstrated safety in human clinical trials, knowledge gained from these studies may enable the evaluation of a novel class of therapeutics for infection-associated MODS.