Signal integration of the death receptor pathways

描述（由申请人提供）：生物系统在许多意义上是复杂的，特别是涉及启动和调节病理生理过程的多种途径。我们感兴趣的是不同的信号事件如何与这些过程中重要的细胞死亡机制相互作用。在早期的研究中，我们在小鼠肝损伤和肝细胞凋亡模型中确定了Bid（一种促死亡Bcl-2家族蛋白）在死亡受体途径和线粒体途径之间的串导中所起的关键作用。从那以后，我们发现新的信号事件参与了这些通路，特别是当TNF-R1参与时。基于我们的初步研究，我们假设JNK和活性氧（reactive oxygen species， ROS）是独立于Bid之外与线粒体激活整合的两个重要机制。我们将探讨JNK在促进tnfa诱导的肝细胞凋亡和肝损伤中的功能（目的1），以及JNK如何以不依赖于bid的方式激活线粒体（目的2）。在Aim 3中，我们将研究ROS在TNFa诱导的肝损伤和肝细胞凋亡中的作用，它们通过NF-KB途径的调节，以及它们如何以不依赖于bid的方式激活线粒体。将采用多种方法，包括利用基因敲除小鼠和RNAi敲除体内基因的体内模型，体外原代细胞培养和生物化学分析。虽然本提案的重点是在TNFa刺激后线粒体水平的一些关键信号传导过程的整合，但我们的长期目标是了解不同的信号通路如何整合以确定病理过程的最终结果，这对新疗法的发展将是重要的。

DESCRIPTION (provided by applicant): The biology system is complicated in many senses, in particular regarding to the multiple pathways involved in initiating and regulating pathophysiological processes. We are interested in how different signaling events could interact with the cell death machinery important to these processes. In earlier studies, we defined the critical role of Bid, a pro-death Bcl-2 family protein, in the cross-talk between the death receptor pathway and the mitochondria pathway in a murine model of liver injury and hepatocyte apoptosis. We have since then found that novel signaling events are involved in the pathways, particularly when TNF-R1 is engaged. Based on our preliminary studies, we hypothesize that JNK and reactive oxygen species (ROS) are two important mechanisms that could integrate with the mitochondrial activation independently of Bid. We will address the function of JNK in promoting TNFa-induced hepatocyte apoptosis and liver injury (Aim 1) and how JNK may activate the mitochondria in a Bid-independent way (Aim 2). In Aim 3, we will investigate the role of ROS in TNFa induced liver injury and hepatocyte apoptosis, their regulation by the NF-KB pathway and how they may activate the mitochondria in a Bid-independent manner. A variety of approaches will be taken, including the in vivo models that utilize gene knockout mice and in vivo gene knockdown by RNAi, in vitro primary cell cultures and biochemistry analysis. While the focus of this proposal is at the integration of some of the key signaling processes at the mitochondria level following TNFa stimulation, our long-term goal is to understand how different signal pathways can be integrated to determine the final outcome of a pathological process, which would be important to the development of novel therapeutics.