Molecular regulation of angiogenesis

描述(申请人提供)：相当多的疾病，包括缺血性心脏和肢体疾病、癌症、糖尿病失明、老年性黄斑变性和类风湿性关节炎，都以血管生成过多或不足为特征。血管内皮生长因子(VEGF)是调节多种内皮细胞(EC)功能和血管生成的主要生长因子。血管内皮生长因子在血管生成中的重要作用为治疗提供了新的机会。然而，对血管内皮生长因子引导血管生成的信号通路的不完全了解仍然是开发有效的抗血管生成癌症治疗或促进血管生成治疗缺血性心脏和四肢疾病的关键障碍。来自我的团队和其他人的新证据支持蛋白激酶D(PKD1)在血管内皮生长因子信号转导和血管生成中的关键作用。PKD1是一个新的丝氨酸/苏氨酸蛋白激酶家族的成员，是潜在的治疗药物靶点。因此，了解PKD1的生物学功能和导致血管生成的特定信号事件是非常必要的。我们首次报道了血管内皮生长因子通过其受体2激活血管内皮细胞中的蛋白酪氨酸激酶1。随后，我们发现PKD1通过组蛋白脱乙酰酶的磷酸化，特别是HDAC7，调节EC的迁移和管状的形成。我的团队的初步观察显示，PKD1通过对EC存活和新血管形成的平行作用，调节血管内皮生长因子介导的血管生成。具体地说，利用基于PKD1基序的筛选策略，我们鉴定了一个与细胞凋亡途径有关的新的PKD1底物。其次，利用基因图谱分析发现，PKD1参与了血管内皮生长因子信号和Notch信号的串扰，在EC形态分化、萌发和血管稳定等新生血管形成过程中起着重要作用。最后，我们的初步研究表明，抑制PKD1在体外和体内都会阻碍血管生成。因此，我们的中心假设是，由血管内皮生长因子激活的PKD1促进了内皮细胞的存活和功能，从而导致血管生成。我们提出了三个强有力且相互关联的目标来验证这一假说：目的1.确定PKD1在血管内皮细胞生长因子诱导的内皮细胞存活中的作用和信号机制。目的2.明确PKD1在血管内皮生长因子和Notch信号相互作用中的作用和分子机制。目的3.研究PKD1及其信号转导通路在小鼠缺血血管生成模型中的作用。目的4.在小鼠肿瘤血管生成模型中评价PKD_1的生物学作用及PKD特异性抑制剂的治疗作用。本文提出的研究将为血管生成中血管生成中血管内皮生长因子-PKD1通路的机制和功能重要性提供深入的认识。这些研究的结果将有助于开发新的治疗方法来预防或治疗血管生成相关疾病。 与公共卫生相关：相当多的疾病，包括缺血性心脏和肢体疾病、癌症、糖尿病失明、老年性黄斑变性和类风湿性关节炎，都以血管生成过多或不足为特征。该项目中提出的研究旨在阐明一种名为PKD1的蛋白质在调节血管内皮功能和新血管形成中的作用。该项目的发现将有助于更好地了解异常血管形成背后的细胞信号机制，并将为发展针对血管生成相关疾病的更有效的靶向干预奠定基础。

DESCRIPTION (provided by applicant): A considerable number of diseases, including ischemic heart and limb diseases, cancer, diabetic blindness, age-related macular degeneration and rheumatoid arthritis, are characterized by excessive or insufficient angiogenesis. Vascular endothelial growth factor (VEGF) is a major growth factor that regulates multiple endothelial cell (EC) functions and angiogenesis. The importance of VEGF in angiogenesis has offered new therapeutic opportunities. However, the incomplete understanding of the signaling pathways whereby VEGF directs angiogenesis remains a critical barrier to developing efficient anti-angiogenic cancer therapy or pro-angiogenic treatment for ischemic heart and limb diseases. Emerging evidence from my group and others supports a crucial role of protein kinase D (PKD1) in VEGF signaling and angiogenesis. PKD1 is a member of a novel family of serine/threonine protein kinases, which are potential druggable targets for therapeutics. As such, it is imperative to understand the biological functions of PKD1 and specific signaling events leading to angiogenesis. We are the first to report that VEGF via its receptor 2 stimulated PKD1 phosphorylation and activation in vascular ECs. Subsequently, we found that PKD1, via phosphorylation of histone deacetylases specifically HDAC7, regulates EC migration and tube formation. Nascent observations from my group now reveal that PKD1, through parallel effects on EC survival and new vessel formation, regulates VEGF-mediated angiogenesis. Specifically, using a PKD1 motif-based screening strategy, we identified a novel PKD1 substrate that is involved in the apoptosis pathway. Second, using gene profile analysis we have found that PKD1 is involved in the crosstalk of VEGF signaling and Notch signaling, which plays an essential role in new vessel formation including EC morphological differentiation, sprouting and vascular stabilization. Finally, our preliminary studies indicate that PKD1 inhibition impedes angiogenesis in vitro and in vivo. Therefore, our central hypothesis is that PKD1 activation by VEGF promotes endothelial survival and functions leading to angiogenesis. Three robust and interrelated aims are proposed to test this hypothesis: Aim 1. Determine the role and signaling mechanisms for PKD1 in VEGF-induced EC survival. Aim 2. Define the role and molecular mechanisms for PKD1 in the interplay of VEGF and Notch signaling. Aim 3. Study the role of PKD1 and signaling pathways in a mouse model of ischemia angiogenesis. Aim 4. Evaluate the biological role of PKD1 and therapeutic effects of a specific PKD inhibitor in a mouse model of tumor angiogenesis. The studies proposed herein will provide mechanistic insights and functional importance of the VEGF-PKD1 pathway in angiogenesis. The results of these studies will facilitate development of new therapeutic approaches to prevent or treat angiogenesis-related diseases. PUBLIC HEALTH RELEVANCE: A considerable number of diseases, including ischemic heart and limb diseases, cancer, diabetic blindness, age-related macular degeneration and rheumatoid arthritis, are characterized by either excessive or insufficient angiogenesis. The studies proposed in this project are designed to elucidate the role of a protein called PKD1 in regulation of vascular endothelial function and new blood vessel formation. The findings from this project will provide a better understanding of cellular signaling mechanisms underlying abnormal blood vessel formation, and will provide an underpinning for the advancement of more effectively targeted interventions aimed at angiogenesis-associated diseases.