Role of Caveolin-1 in Cellular Senescence and Aging

衰老的表现之一是细胞和有机体水平上损伤的积累。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，活性氧已被证明可以促进培养细胞过早衰老，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，被细胞用于区隔和功能调节信号分子。我们最近已经证明，过度表达caveolin-1足以使小鼠胚胎成纤维细胞处于细胞周期的G0/G1期，并诱导细胞过早衰老。然而，小洞蛋白-1是否在促进细胞衰老中起核心作用尚不清楚。在本提案中，我们计划验证caveolin-1在氧化应激诱导的过早衰老（SIPS）中起关键作用的假设。本建议的三个长期目标是：表征小窝蛋白-1启动子对氧化应激的反应。2. 探讨小泡蛋白-1在SIPS中对p53通路的调节作用。3. 鉴定氧化应激后囊泡膜富集的信号分子。为了表征caveolin-1启动子对氧化应激的反应，我们建议鉴定在细胞对氧化应激反应中刺激caveolin-1基因表达的转录因子。为了研究小洞蛋白-1对p53通路的调节，我们将验证小洞蛋白-1通过将Mdm-2隔离到小洞膜中来激活p53的假设。为了鉴定氧化应激后进入小泡膜的信号分子，我们计划使用基于蛋白质组学的方法克隆和表征氧化刺激后进入小泡膜的信号分子。了解氧化应激诱导的过早衰老的信号转导机制将为自由基衰老理论提供新的见解。

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.