BIOCHEMICAL MECHANISMS OF OXIDATIVE INJURY IN TRAUMA

Rac GTP酶控制的人吞噬细胞NADPH氧化酶是 负责形成超氧阴离子和其他氧化剂 被这些细胞用来杀死细菌，也是一种重要的 炎症反应的贡献者。NADPH氧化酶是直接 在单核细胞中受到内毒素的刺激，内毒素起到“启动”氧化剂的作用 在其他白细胞中产生，从而增强炎症 败血症休克期间发生的损害。我们将调查 Rac-GTP酶调节的白细胞反应与血管紧张素转换酶的关系 内毒素利用的信号机制。 为响应内毒素而形成的新型脂质介体将被测试 破坏Rho家族GTP酶调控复合体的能力 RhoGDI。我们将使用直接结合测量和活性分析。 以评估此机制对RAC签名的可能影响。这个 Rac在125诱导的吞噬细胞氧化反应中的作用 将使用遗传方法进行测试。通过RAC向p38 MAPK发送信号 也将被检验，我们将评估RAC- 受调控的激酶，如p38，控制着 NADPH氧化酶。NADPH氧化酶组分上的磷酸化位点 将被鉴定为p38，并且这种酶对 评估了氧化物酶组件。最后，RAC可能的连接 GTP酶对脂多糖和细胞因子调节的转录激活的影响 将评估核因子-kB。这些研究应该澄清 内毒素介导炎性组织损伤的机制 感染性休克综合征。

The Rac GTPase-controlled NADPH oxidase of human phagocytes is responsible for the formation of superoxide anion and other oxidants used by these cells for bacterial killing, and is also an important contributor to the inflammatory response. NADPH oxidase is directly stimulated by LPS in monocytes, and LPS serves to "prime" oxidant production in other leukocytes, thereby enhancing the inflammatory damage occurring during septic shock. We will investigate the connections between Rac GTPase-regulated responses of leukocytes and the signaling mechanisms utilized by LPS. Novel lipid mediators formed in response to LPS will be tested for the ability to disrupt regulatory complexes of Rho family GTPases and RhoGDI. We will use both direct binding measurements and activity assays to evaluate possible effects on Rac signing by this mechanism. The contribution of Rac to the phagocyte oxidative responses induced by 125 will be tested using genetic approaches. Signaling via Rac to p38 MAPK will be examined as well, and we will evaluate the hypothesis that Rac- regulated kinases such as p38 control the coordinated assembly of the NADPH oxidase. Sites on NADPH oxidase components that are phosphorylated by p38 will be identified, and the contribution of this enzyme to oxidase assembly assessed. Finally, the possible connection of Rac GTPase to activation of the LPS- and cytokine-regulated transcription factor NF-kB will be evaluated. These studies should clarify the mechanisms by which LPS mediates inflammatory tissue damage during septic shock syndromes.