Activation of alpha5beta3 integrin on blood and endothelial cells

血液和内皮细胞上 α5β3 整合素的激活

• 批准号: 7253409
• 负责人: Tatiana V Byzova
• 金额: $ 32.64万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-14 至 2009-01-11
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7253409
• 关键词: 1-Phosphatidylinositol 3-Kinase; Affinity; Agonist; Animals; Apoptosis; Atherosclerosis; Avidity; Binding; Biological; Biology; Blood; Blood Platelets; Blood Vessels; Cardiovascular Diseases; Cell Adhesion; Cell Line; Cell membrane; Cell surface; Cells; Complex; Cytoplasmic Tail; Data; Development; Doctor of Philosophy; Endothelial Cells; Environment; Event; Extracellular Domain; Extracellular Matrix; Family; Fibrinogen; Gene Expression; Genes; Goals; Growth Factor; In Vitro; Inflammation; Injury; Integrin Binding; Integrin alphaVbeta3; Integrin beta3; Integrins; Ligand Binding; Ligands; Literature; Malignant Neoplasms; Mediating; Molecular; Mus; Mutate; Pathway interactions; Phosphoinositide-3-Kinase, Catalytic, Gamma Polypeptide; Phosphotransferases; Physiological; Platelet aggregation; Play; Principal Investigator; Process; Property; Range; Regulation; Rest; Role; Series; Signal Transduction; Site; Testing; Thrombus; VEGF165; Vascular Endothelial Growth Factor Receptor; Vascular Endothelial Growth Factor Receptor-1; Vascular Endothelial Growth Factor Receptor-2; Vascular Endothelial Growth Factors; angiogenesis; cytokine; in vivo; insight; migration; mutant; programs; receptor; response; restenosis; therapeutic angiogenesis; therapeutic target

DESCRIPTION (provided by applicant): The family of cell surface molecules, the integrins, mediates multiple physiological and pathological responses, including inflammation, atherosclerosis and cancer development, thrombus formation and angiogenesis. Indeed, several integrins are therapeutic targets for cardiovascular diseases and for cancer. However, recent findings indicate that our understanding of the role of integrins in general and alphavbeta3 in particular in angiogenesis is incomplete. The central hypothesis of this proposal is that cellular interaction of integrin alphavbeta3 with matrix ligands is tightly controlled and depends on the activation state of the receptor. A physiologically important activation mechanism of alphavbeta3 is mediated by angiogenic growth factors of the VEGF family acting through their receptors, and the consequence of this activation will be evident in the angiogenic response in vivo. Akt will play a pivotal role in activation of alphavbeta3 and this role can be most convincingly demonstrated by comparing the consequences of inactivation of the Akt gene on the function of alphavbeta3 and alphaIIbeta3. The following Specific Aims are proposed to test this hypothesis: Aim I. To determine the molecular mechanisms for alphavbeta3 activation by VEGFRs. a) We will determine whether alphavbeta3 activation is mediated exclusively by VEGFR-2 using growth factors with selective receptor activity as well as cell lines expressing this VEGF receptor; b) Knowing that VEGFR-2 can activate alphavbeta3, we will dissect the requirements for VEGFR-2 to transmit a signal leading to alphavbeta3 activation using cells expressing mutant VEGFR-2 receptors; c) The structural requirements for beta3 integrin subunit to receive an activating signal will be determined using truncated and mutated forms of the cytoplasmic tail of the beta3 integrin subunit; d) the requirement for a physical association between alphavbeta3 and VEGFR-2 will be assessed and compared to that of VEGFR-1. Aim II. To characterize the functional consequences of activation of integrin alphavbeta3 in vitro and in vivo. We will determine: a) how alphavbeta3 activation by VEGF controls the recognition of specific physiological ligands; and b) whether avb3 activation occurs in sites of injury or therapeutic angiogenesis in vivo. Aim IlI. To establish the role of the Akt pathway in activation of the two beta3 integrins in vitro and in vivo. We will: a) manipulate the activity of Akt-1 in vitro using transfected cells and determine its role in alphavbeta3 activation; b) combine an analysis of transfected cells and cells from Akt-1 null animals to determine if Akt is necessary for the activation of both beta3 integrins; c) We will characterize the role of Akt in alphavbeta3 activation in vivo in the process of VEGF-stimulated angiogenesis in normal and Akt-1 null animals and in alphavbeta3 activation in platelet mediated responses in vivo. Our efforts to determine the mechanisms and significance of beta3 integrin activation should provide new insights into regulation of integrin functions in physiological and pathophysiological settings and identify new targets for therapy.

描述（由申请人提供）：细胞表面分子家族整合素介导多种生理和病理反应，包括炎症、动脉粥样硬化和癌症发展、血栓形成和血管生成。事实上，几种整联蛋白是心血管疾病和癌症的治疗靶标。然而，最近的研究结果表明，我们对整合素的作用，特别是α v β 3在血管生成中的理解是不完整的。该提议的中心假设是整合素α v β 3与基质配体的细胞相互作用受到严格控制，并取决于受体的活化状态。α v β 3的生理学上重要的活化机制由VEGF家族的血管生成生长因子介导，所述血管生成生长因子通过其受体起作用，并且这种活化的结果在体内血管生成应答中是明显的。Akt将在α v β 3的激活中发挥关键作用，并且通过比较Akt基因失活对α v β 3和α II β 3功能的影响可以最令人信服地证明这种作用。提出以下具体目标来检验这一假设：目标I。确定VEGF激活α v β 3的分子机制。a）我们将使用具有选择性受体活性的生长因子以及表达该VEGF受体的细胞系来确定α v β 3活化是否仅由VEGFR-2介导; B）已知VEGFR-2可以活化α v β 3，我们将使用表达突变型VEGFR-2受体的细胞来剖析VEGFR-2传递导致α v β 3活化的信号的要求; c）使用β 3整联蛋白亚基的胞质尾区的截短和突变形式来确定β 3整联蛋白亚基接收活化信号的结构要求; d）评估α v β 3和VEGFR-2之间物理缔合的要求并与VEGFR-1的要求进行比较。Aim II.表征整合素α v β 3在体外和体内活化的功能后果。我们将确定：a）VEGF对α v β 3的激活如何控制特异性生理配体的识别;和B）体内avb 3激活是否发生在损伤部位或治疗性血管生成部位。目标III。确定Akt通路在体外和体内两种β 3整合素活化中的作用。我们将：B）联合收割机分析转染的细胞和Akt-1缺失动物的细胞，以确定Akt是否是激活两种β 3整联蛋白所必需的; c）我们将表征在正常和Akt-1中VEGF刺激的血管生成过程中Akt在体内α v β 3活化中的作用。1无效动物和体内血小板介导的应答中的α v β 3活化。我们的努力，以确定β 3整合素激活的机制和意义，应提供新的见解，在生理和病理生理环境中的整合素功能的调节，并确定新的治疗目标。