Mechanisms of microvascular remodeling progression

微血管重塑进展机制

• 批准号: 8282837
• 负责人: Luis A Martinez-Lemus
• 金额: $ 36.12万
• 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 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8282837
• 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. PUBLIC HEALTH RELEVANCE: Public Health Relevance Statement In people with high blood pressure, the small blood vessels known as resistance arterioles undergo a process of structural remodeling that reduces their internal diameter and increases the risk for heart attacks and stroke. The goal of this project is to understand the mechanisms that control this remodeling. This understanding will allow us to develop novel strategies for preventing, stopping, and/or reversing the remodeling process and the life threatening events that are associated with it.

描述（由申请人提供）：血管重塑是一种自适应机制，用于长期修饰血管直径。在高血压中，向内重塑，即耐药容器中管腔直径的结构降低，与心肌梗塞和中风的风险增加有关。然而，尽管它与威胁生命的心血管事件相关联，但对启动和指导抗性微血管中向内重塑进展的机制知之甚少。在这方面，我们将重塑过程视为在结构改变的容器中达到顶点的事件的连续性。我们奇异的新颖和挑衅性的假设是，持续的小动脉血管收缩响应长时间的体液，和/或机械刺激启动重塑机制，其特征是以下特征：1）部分细胞外基质（ECM）组件的部分降解（周转）； 2）血管平滑肌（VSM）细胞骨架的重排； 3）通过取决于活性氧（ROS）的细胞产生的过程来重新定位VSM细胞附着。使用在实验室中开发的高度创新的多光子成像技术，我们最近证明了分离的小动脉中的VSM细胞在长时间的血管收缩（高血压的标志）期间重新延长并迅速改变位置，同时维持减少的动脉直径。这种现象发生在短短四个小时内，我们建议是一种与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）小G蛋白Rho的ROS依赖性调节诱导钙敏化并重塑VSM细胞骨架； 3）依赖ROS依赖于整联蛋白依赖性VSM细胞附着的调制。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。借助插入显微镜，我们将在体内监测血管重塑，并在多光子显微镜下，我们将确定分离的动脉中的VSM细胞行为和ECM变化。使用原子力显微镜（AFM）和荧光成像，我们将对新鲜分离的VSM细胞应用离散力，并监测局灶性粘附（细胞附着）和细胞骨架重塑。这些方法与分子和药理学技术结合使用，将在我们的特定目的中使用，以确定ROS，MMP，RHO和整合素在重塑中的作用。这些方法将为测试我们的假设和整合结果提供强大的策略。我们的长期目标是表征导致高血压中电阻血管结构修饰的机制。这些根本重要的机械研究将使我们能够制定新的策略来预防，停止和/或反向重塑以及与之相关的威胁生命的事件。公共卫生相关性：高血压患者的公共卫生相关性声明，被称为抗性小动脉的小血管经历了结构性改造的过程，可降低其内径，并增加心脏病发作和中风的风险。该项目的目的是了解控制这种重塑的机制。这种理解将使我们能够制定新的策略，以防止，停止和/或逆转重塑过程以及与之相关的威胁生命的事件。