Mechanisms of Microvascular Remodeling Progression

微血管重塑进展机制

• 批准号: 8470212
• 负责人: Luis A Martinez-Lemus
• 金额: $ 34.36万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8470212
• 关键词: Adhesions; Atomic Force Microscopy; Blood Vessels; Calcium; Caliber; Cardiovascular system; Cell-Matrix Junction; Collagen Type I; Cytoskeleton; DNA Sequence Rearrangement; Event; Extracellular Matrix; Extracellular Matrix Degradation; Fibronectins; Focal Adhesions; Goals; Health; Hour; Hypertension; Image; Imaging Techniques; Immunohistochemistry; Integrins; Laboratories; Length; Life; Matrix Metalloproteinases; Measures; Mechanics; Methodology; Microscopy; Modeling; Modification; Molecular; Monitor; Monomeric GTP-Binding Proteins; Myocardial Infarction; Positioning Attribute; Process; Production; Reactive Oxygen Species; Research; Resistance; Risk; Role; Smooth Muscle Myocytes; Stimulus; Stroke; Structure; Techniques; Testing; Therapeutic procedure; Vascular Smooth Muscle; Vascular remodeling; Vasoconstrictor Agents; Vasodilator Agents; arteriole; cell behavior; fluorescence imaging; in vitro Model; in vivo; in vivo Model; innovation; intravital microscopy; molecular imaging; novel; novel strategies; prevent; prophylactic; public health relevance; research study; response; rho; vasoconstriction

DESCRIPTION (provided by applicant): Vascular remodeling is an adaptive mechanism for long-term modification of vascular diameter. In hypertension, inward remodeling, that is, the structural reduction of the lumen diameter in resistance vessels, is associated with an increased risk for myocardial infarction and stroke. However, despite its association with life threatening cardiovascular events, little is known about the mechanisms that initiate and guide the progression of inward remodeling in the resistance microvessels. In this regard, we view the remodeling process as a continuum of events that culminate in the structurally altered vessel. Our singularly novel and provocative hypothesis is that sustained arteriolar vasoconstriction in response to prolonged humoral, and/or mechanical stimuli initiates remodeling mechanisms characterized by: 1) partial degradation (turnover) of the extracellular matrix (ECM) components of the vessel wall; 2) rearrangement of the vascular smooth muscle (VSM) cytoskeleton; and 3) repositioning of the VSM cellular attachments via processes that depend on the cellular production of reactive oxygen species (ROS). Using a highly innovative multiphoton imaging technique developed in our laboratories, we recently demonstrated that VSM cells in isolated arterioles re-lengthen and rapidly change position during prolonged vasoconstriction (a hallmark of hypertension) while the reduced arteriolar diameter is maintained. This phenomenon occurs in as little as four hours, and we propose is an early mechanism associated with inward remodeling. We further hypothesize that other mechanisms occur concurrently, including: 1) ROS-dependent activation of matrix metalloproteinases (MMP) to degrade the ECM; 2) ROS-dependent modulation of the small G protein Rho to induce calcium sensitization and remodel the VSM cytoskeleton; and 3) ROS-dependent modulation of integrin-dependent VSM cell attachments. We will test our hypotheses in three in vivo and two in vitro models using state of the art imaging and molecular approaches. With intravital microscopy we will monitor vascular remodeling in vivo, and with multiphoton microscopy, we will determine VSM cell behavior and ECM changes in isolated arterioles. With atomic force microscopy (AFM) and fluorescence imaging we will apply discrete forces to freshly isolated VSM cells and monitor focal adhesion (cellular attachments) and cytoskeletal remodeling. These methodologies combined with molecular and pharmacological techniques will be used in our Specific Aims to determine the role of ROS, MMPs, Rho, and integrins on remodeling. These approaches will provide a powerful strategy for testing our hypotheses and integrating our results. Our long-term goal is to characterize the mechanisms leading to the structural modification of resistance vessels in hypertension. These fundamentally important mechanistic studies will allow us to develop new strategies to prevent, stop, and/or reverse remodeling and the life threatening events associated with it.

描述（由申请人提供）：血管重塑是血管直径长期改变的适应性机制。在高血压中，向内重塑，即阻力血管管腔直径的结构性减小，与心肌梗塞和中风的风险增加相关。然而，尽管它与危及生命的心血管事件有关，但人们对阻力微血管内向重塑的启动和引导进展的机制知之甚少。在这方面，我们将改造过程视为一个连续的事件，最终导致船舶结构发生改变。我们独特新颖且具有启发性的假设是，响应于长时间的体液和/或机械刺激而持续的小动脉血管收缩启动了重塑机制，其特征在于：1）血管壁的细胞外基质（ECM）成分部分降解（周转）； 2）血管平滑肌（VSM）细胞骨架的重排； 3) 通过依赖于细胞活性氧 (ROS) 产生的过程重新定位 VSM 细胞附着物。使用我们实验室开发的高度创新的多光子成像技术，我们最近证明，在长时间的血管收缩（高血压的标志）期间，孤立的小动脉中的 VSM 细胞重新延长并快速改变位置，同时保持减小的小动脉直径。这种现象在短短四个小时内就会发生，我们认为这是一种与向内重塑相关的早期机制。我们进一步假设其他机制同时发生，包括：1）基质金属蛋白酶（MMP）的ROS依赖性激活以降解ECM； 2）ROS依赖性调节小G蛋白Rho诱导钙敏化并重塑VSM细胞骨架； 3) 整合素依赖性 VSM 细胞附着的 ROS 依赖性调节。我们将使用最先进的成像和分子方法在三个体内和两个体外模型中测试我们的假设。通过活体显微镜，我们将监测体内血管重塑，通过多光子显微镜，我们将确定离体小动脉中的 VSM 细胞行为和 ECM 变化。通过原子力显微镜 (AFM) 和荧光成像，我们将向新鲜分离的 VSM 细胞施加离散力，并监测粘着斑（细胞附着）和细胞骨架重塑。这些方法与分子和药理学技术相结合，将用于我们的具体目标，以确定 ROS、MMP、Rho 和整合素在重塑中的作用。这些方法将为检验我们的假设和整合我们的结果提供强大的策略。我们的长期目标是确定导致高血压阻力血管结构改变的机制。这些至关重要的机制研究将使我们能够制定新的策略来预防、停止和/或逆转重塑以及与之相关的危及生命的事件。