Cross talk between cav-1 and flot1 in lung injury

描述(由申请人提供)：急性肺损伤(ALI)及其严重形式的急性呼吸窘迫综合征(ARDS)是导致严重发病率和死亡率的破坏性综合征。ARDS的发病机制仍然知之甚少，治疗选择仍然有限。高氧性肺损伤是一种已建立的模拟人类ARDS的模型，已被研究人员广泛使用。肺上皮细胞死亡是ALI的一个重要特征，在ALI/ARDS的发病机制中起关键作用。细胞死亡是由信号分子调节的，信号分子已被证明聚集在脂筏上。Caveolin-1(Cav-1)和Flotilin1(Flot1)是脂筏标志物蛋白，在多种肺细胞中高表达。然而，Flot1在呼吸生物学中的调节和功能一直没有得到很好的研究，如果有的话。根据我们已发表的和初步的研究，我们认为Cav-1和Flot1是重要的效应分子，在ALI和高氧诱导的上皮细胞死亡的发病机制中发挥关键作用。我们已发表的工作表明，Cav-1基因缺失的小鼠对高氧诱导的ALI具有抵抗力。自我们上次提交以来，我们最新发表的数据进一步表明，Cav-1通过抑制Survivin增加了高氧诱导的细胞凋亡。与Cav-1相比，我们的数据显示Flot1可以保护细胞免受高氧诱导的细胞死亡。Cav-1和Flot1通过不依赖FasL的Fas途径共同调控高氧诱导的细胞死亡。Flot1和Cav-1在高氧后均与Fas相互作用，表明Cav-1和Flot1相互作用并介导死亡信号。我们推测Cav-1、Flot1及其相互作用通过调节Fas信号通路调控高氧诱导的上皮细胞死亡和ALI。我们预计，我们的研究将为开发治疗急性肺损伤的方法确定新的靶点。我们将在以下特定目标中验证我们的假设：目的1：确定Cav-1的功能作用以及Cav-1介导高氧诱导的上皮细胞死亡的潜在机制。目的：探讨Flot1在高氧诱导的肺上皮细胞死亡和肺损伤中的调节和作用。目的：探讨Cav-1和Flot1在高氧诱导的肺上皮细胞死亡和肺损伤中的相互作用。

DESCRIPTION (provided by applicant): Acute lung injury (ALI) and its severe form acute respiratory distress syndrome (ARDS) are devastating syndromes responsible for significant morbidity and mortality. The pathogenesis of ARDS is still poorly understood and therapeutic options remain limited. Hyperoxia-induced lung injury is an established model which mimics human ARDS and has been used extensively by investigators. Lung epithelial cell death is a key feature of ALI and is crucial in the pathogenesis of ALI /ARDS. Cell death is regulated by signaling molecules, which have been shown to congregate on lipid rafts. Caveolin-1 (cav-1) and flotillin1(flot1) have been identified as lipid raft marker proteins, which are highly expressed in various lung cells. However, the regulation and function of flot1 in respiratory biology has been poorly, if at all, studied. Based on our published and preliminary studies, we believe that cav-1 and flot1 are important effector molecules which play critical roles in the pathogenesis of ALI and hyperoxia-induced epithelial cell death. Our published work has demonstrated that cav-1 null mice are resistant to hyperoxia induced ALI. Since our previous submission, our newly published data further showed that cav-1 increases hyperoxia-induced apoptosis via suppressing survivin. In contrast to cav-1, our data showed that flot1 protects against hyperoxia induced cell death. Cav-1 and flot1 together regulate hyperoxia induced cell death via Fas pathways independent of FasL. Flot1 and cav-1 both interacted with Fas after hyperoxia, indicating that cav-1 and flot1 cross talk and mediate the death signaling. We hypothesize that cav-1, flot1 and their cross-talk modulate hyperoxia induced epithelial cell death and ALI via regulating Fas signaling pathways. We anticipate that our studies will lead to the identification of novel targets for the development of therapeutic approaches against acute lung injury. We will test our hypothesis in the following specific aims: Aim1I: To determine the functional role of cav-1 and the underlying mechanisms by which cav-1 mediates hyperoxia induced epithelial cell death. Aim 2: To determine the regulation and function of flot1 in hyperoxia induced lung epithelial cell death and lung injury. Aim 3: To determine the cross-talk between cav-1 and flot1 in hyperoxia induced lung epithelial cell death and lung injury.