Forkhead signaling in the endothelium

描述(申请人提供)：内皮细胞(EC)表型在健康和疾病中表现出显著的异质性。血管生物学的一个重要目标是了解EC表型的时空调控的分子机制。这一竞争性的更新申请是我们之前工作的延伸，目的是阐明叉头(FOXO)转录因子在EC生物学中的作用。在过去的三年中，FOXO生物学出现了三个新的和令人兴奋的方面，加上我们自己发表的数据和初步结果，为目前的提议提供了坚实的基础：1)尽管FOXO蛋白普遍表达，但FOXO缺陷小鼠显示出血管表型，无论该基因在胚胎发育期间还是在成年鼠中被删除，2)血管表型是器官特有的，来自不同器官的FOXO缺陷内皮细胞显示出不同的基因表达模式和功能变化，以及3)FOXO蛋白(至少在其他细胞类型中)已被证明与广泛的转录因子结合和/或相互作用。基于这些考虑，我们假设FOXO蛋白(特别是FOXO1)与其他转录因子合作调节EC表型。总体目标是确定内皮细胞中FOXO1相关的转录网络，了解这些转录网络如何调节血管床特异基因的表达，并确定FOXO1在完整内皮细胞中的体内作用。目的1研究血管内皮细胞中FOXO1与其他转录因子的功能相互作用。目的2研究FOXO1和NF-kB对血管内皮细胞的基因调控。目的3分析在正常和病理状态下条件性FOXO1的过度表达和敲除对EC功能和功能障碍的影响。 与公共卫生相关：该提案意义重大，因为它将为FOXO1介导的EC信号转导的机制(从而治疗潜力)提供重要的见解。

DESCRIPTION (provided by applicant): Endothelial cell (EC) phenotypes display remarkable heterogeneity in health and disease. An important goal in vascular biology is to understand the molecular mechanisms underlying the spatial and temporal modulation of EC phenotypes. This competing renewal application is an extension of our previous work aimed towards elucidating the role of forkhead (FOXO) transcription factors in EC biology. Three novel and exciting aspects of FOXO biology have emerged in the past 3 years, which together with our own published data and preliminary results provide a strong foundation for the current proposal: 1) despite the fact that FOXO proteins are ubiquitously expressed, FOXO- deficient mice display a vascular phenotype, whether the gene is deleted during embryogenesis or in adults, 2) the vascular phenotype is organ-specific and FOXO-deficient ECs from different organs demonstrate different gene expression patterns and functional changes, and 3) FOXO proteins (at least in other cell types) have been shown to bind to and/or interact with a broad spectrum of transcription factors. Based on these considerations, we hypothesize that FOXO proteins (in particular FOXO1) cooperate with other transcription factors to regulate EC phenotypes. The overall goal is to identify FOXO1-associated transcriptional networks in ECs, to understand how these mediate vascular bed-specific gene expression, and to define the in vivo role of FOXO1 in the intact endothelium. Aim 1 is to characterize functional interactions between FOXO1 and other transcription factors in ECs. Aim 2 is to characterize combinatorial gene regulation by FOXO1 and NF-kB in ECs. Aim 3 is to analyze the effect of conditional FOXO1 over-expression and knockout on EC function and dysfunction in normal and pathological states. PUBLIC HEALTH RELEVANCE: The proposal is significant in that it will provide important insights into the mechanisms (hence therapeutic potential) of FOXO1-mediated EC signal transduction.