Role of Caveolin-1 in Cellular Senescence and Aging

衰老的表现之一是在细胞和机体水平上积累损伤。这种损伤是由内源性和外源性刺激引起的，包括氧化应激。有趣的是，在培养中，活性氧物种被证明能促进细胞的过早衰老，这被认为在更复杂的衰老过程中起着重要作用。小窝蛋白-1是小窝的结构成分，被细胞用来区分和功能调节信号分子。我们最近已经证明，小窝蛋白-1的过度表达足以将小鼠胚胎成纤维细胞阻止在细胞周期的G0/G1期，并诱导细胞过早衰老。然而，小窝蛋白-1是否是促进细胞衰老的中心角色仍不清楚。在这项提案中，我们计划测试这一假设，即小窝蛋白-1代表氧化应激诱导的早衰(SiPS)的关键参与者。这项建议的三个长期目标是：1.表征小窝蛋白-1启动子对氧化应激的反应。2.探讨小窝蛋白-1对SIPs中P53信号通路的调节作用。3.确定氧化应激后哪些信号分子被富含到腔膜中。为了研究小凹蛋白-1启动子对氧化应激的反应，我们建议找出在细胞对氧化应激反应过程中刺激小凹蛋白-1基因表达的转录因子。为了研究小凹蛋白-1对P53途径的调控，我们将检验小窝蛋白-1通过将MDM-2隔离到小窝细胞膜中而激活P53的假说。为了确定氧化应激后进入小窝的信号分子，我们计划使用一种基于蛋白质组的方法来克隆和表征在氧化剂刺激下进入小窝的信号分子。了解氧化应激诱导的早衰的信号转导机制将为衰老的自由基理论提供新的见解。

One of the manifestations of aging is the accumulation of damage at both cellular and organism levels. This damage is initiated by endogenous and exogenous stimuli, including oxidative stress. Interestingly, reactive oxygen species have been shown to promote premature cellular senescence in culture, which is believed to have an important role in the more complicated ageing process. Caveolin-1 is the structural component of caveolae and is used by the cell to compartmentalize and functionally regulate signaling molecules. We have recently demonstrated that over-expression of caveolin-1 is sufficient to arrest mouse embryonic fibroblasts in the G0/G1 phase of the cell cycle and induce premature cellular senescence. However, whether caveolin-1 is a central figure in promoting cellular senescence remains unknown. In this proposal, we plan to test the hypothesis that caveolin-1 represents a key player in oxidative stress-induced premature senescence (SIPS). The three long-term objectives of this proposal are: 1. To characterize the caveolin-1 promoter response to oxidative stress. 2. To investigate modulation of the p53 pathway by caveolin-1 in SIPS. 3. To identify signaling molecules that are enriched into caveolar membranes after oxidative stress. In order to characterize the caveolin-1 promoter response to oxidative stress, we propose to identify the transcription factors that stimulate caveolin-1 gene expression during the cellular response to oxidative stress. To investigate modulation of the p53 pathway by caveolin-1 we will test the hypothesis that caveolin-1 activates p53 by sequestering Mdm-2 into caveolar membranes. To identify signaling molecules that are enriched into caveolar membranes after oxidative stress, we plan to use a proteomic-based approach to clone and characterize signaling molecules that move into caveolae upon oxidant stimulation. Understanding the signal transduction machinery involved in oxidative stress-induced premature senescence will provide new insights into the free radical theory of aging.