Mechanically Stressed VSMC: A Role for Slingshot Phosphatase in Inflammation

机械应力 VSMC：弹弓磷酸酶在炎症中的作用

• 批准号: 8996699
• 负责人: Alejandra San Martin
• 金额: $ 39万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-02-15 至 2018-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8996699
• 关键词: Actin-Binding Protein; Actins; Animal Model; Aortic coarctation; Arteries; Attenuated; Binding; Biochemical; Biomechanics; Blood Vessels; Cardiovascular Diseases; Cardiovascular system; Caveolae; Cell Nucleus; Cells; Cellular biology; Cytoskeleton; DNA Binding; Data; Disease; Down-Regulation; Event; Focal Adhesions; Gene Expression; Genes; Genetic Transcription; Grant; Growth; Health; Hydrogen Peroxide; Hypertension; Immigration; In Vitro; Inflammation; Inflammatory; Integrins; Knock-out; LIM Domain Kinase 1; LIMK1 gene; Lead; Mechanical Stimulation; Mechanical Stress; Mechanics; Mediating; Molecular; NADPH Oxidase; Nuclear; Nuclear Translocation; Oxidation-Reduction; Pathway interactions; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Platelet-Derived Growth Factor; Play; Production; Proteins; Reactive Oxygen Species; Regulation; Risk Factors; Rodent; Role; Signal Transduction; Signaling Molecule; Site; Smooth Muscle Myocytes; Source; Stimulus; Stress; Stress Fibers; Stretching; Superoxides; Testing; Tissues; Vascular Smooth Muscle; base; cofilin; design; extracellular; gain of function; heat-shock factor 1; hemodynamics; in vivo; in vivo Model; knockout animal; new therapeutic target; oxidation; pressure; research study; response; therapeutic development; transcription factor; vascular inflammation; vascular smooth muscle cell migration

DESCRIPTION (provided by applicant): Cell and tissues are subjected to different types of mechanical stress. Hypertension is a pathological state in which the increase in pressure induces enhanced mechanical forces within the vessel wall. One of the consequences of hypertension is the induction of inflammatory gene expression in the vasculature. Although inflammation may facilitate hypertension-related cardiovascular complications, the molecular pathways that result in hypertension-induced inflammation are incompletely described vascular smooth muscle cells (VSMCs), a main component of the vessel wall, respond to biomechanical forces initiated by hemodynamic changes and undergo phenotypic modulation. Indeed, this modulation results in reorientation of the cell body, which has been proposed as one mechanism to counteract the strain. Reactive oxygen species (ROS) play important roles as signaling molecules in all types of vascular cells. One main source of ROS in the vasculature is Nox4, which is found in focal adhesions (FAs), the sites of engagement of the cell to the extracellular substrate. We have shown that Slingshot 1L (SSH1L) phosphatase, which dephosphorylates and thus activates its substrate, the actin binding protein cofilin, plays a key role in the control of PDGF-induced lamellipodia formation and VSMC migration. Now, we have exciting preliminary data indicating that SSH1L-mediated cofilin activation is required for cell reorientation and, most significantly, for the regulation of inflammatory gene expression when VSMC are subjected to mechanical stress. We hypothesize that in response to mechanical stress, integrins activate the Nox4-based NADPH oxidase to produce H2O2 that induces SSH1IL-mediated cofilin activation within the FA, and that activated cofilin is required for cell reorientation and translocates to the nucleus where it regulates the transcription of inflammatory genes. During this grant period we aim to: 1. Identify the mechanism of mechanical stretch-induced SSH1L/cofilin activation and its role in cell reorientation in VSMC, 2. Define the mechanism of cofilin nuclear translocation and its role in regulating the gene expression and 3. Determine the role of the Nox4/cofilin pathway in attenuating hypertension-induced vascular inflammation in vivo. Experiments described in this application will increase our understanding about how cells sense mechanical stimuli and the consequences of such stimuli on cell phenotype, providing sufficient proof-of principle to support the identification of new therapeutic targets.

描述(申请人提供)：细胞和组织受到不同类型的机械应力。高血压是一种病理状态，在这种状态下，压力的增加会导致血管壁内机械力的增强。高血压的后果之一是诱导血管系统中炎症基因的表达。虽然炎症可以促进高血压相关的心血管并发症，但导致高血压引起炎症的分子通路尚未完全被描述，血管平滑肌细胞(VSMCs)是血管壁的主要组成部分，它响应血流动力学变化引发的生物力学压力并经历表型调节。事实上，这种调节会导致细胞体的重新定位，这已被认为是抵消应变的一种机制。活性氧簇(ROS)在各种类型的血管细胞中作为信号分子发挥着重要作用。血管系统中ROS的一个主要来源是NOX4，它存在于局部粘连(FAs)中，FAs是细胞与细胞外基质的结合部位。我们已经证明，Slingshot 1L(SSH1L)磷酸酶可以去磷酸化并激活其底物肌动蛋白结合蛋白cofilin，在PDGF诱导的片状脂肪形成和VSMC迁移的控制中发挥关键作用。现在，我们有了令人兴奋的初步数据表明，SSH1L介导的cofilin激活是细胞重新定位所必需的，最重要的是，当VSMC受到机械应力时，对炎症基因表达的调控是必需的。我们假设，在机械应力的响应下，整合素激活基于NOX4的NADPH氧化酶产生过氧化氢，从而诱导SSH1IL介导的cofilin在FA内激活，并且激活的cofilin是细胞重新定位所必需的，并移位到细胞核，在那里它调节炎症基因的转录。在此期间，我们的目标是：1.确定机械拉伸诱导的SSH1L/cofilin激活的机制及其在VSMC细胞重定向中的作用；2.确定cofilin核转位的机制及其在基因表达调控中的作用；3.确定NOX4/cofilin途径在体内减轻高血压诱导的血管炎症中的作用。本申请中描述的实验将增加我们对细胞如何感知机械刺激以及这种刺激对细胞表型的影响的理解，为识别新的治疗方法提供充分的原理证据 目标。