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（由申请人提供）：细胞和组织承受不同类型的机械应力。高血压是一种病理状态，其中压力的增加导致血管壁内的机械力增强。高血压的后果之一是诱导脉管系统中炎症基因的表达。尽管炎症可能促进高血压相关的心血管并发症，但导致高血压诱发炎症的分子途径尚未完全描述。血管平滑肌细胞（VSMC）是血管壁的主要组成部分，对血流动力学变化引发的生物力学力做出反应并经历表型调节。事实上，这种调节会导致细胞体重新定向，这被认为是抵消压力的一种机制。 活性氧（ROS）作为信号分子在所有类型的血管细胞中发挥着重要作用。脉管系统中 ROS 的主要来源之一是 Nox4，它存在于粘着斑 (FA) 中，即细胞与细胞外基质的接合部位。 我们已经证明，Slingshot 1L (SSH1L) 磷酸酶可去磷酸化并从而激活其底物肌动蛋白结合蛋白丝切蛋白，在控制 PDGF 诱导的板状伪足形成和 VSMC 迁移中发挥关键作用。现在，我们有令人兴奋的初步数据表明，细胞重新定向需要 SSH1L 介导的肌动蛋白丝切蛋白激活，最重要的是，当 VSMC 受到机械应力时，它需要调节炎症基因表达。我们假设，为了响应机械应力，整合素激活基于 Nox4 的 NADPH 氧化酶，产生 H2O2，从而诱导 FA 内 SSH1IL 介导的丝切蛋白激活，并且激活的丝切蛋白是细胞重新定向和易位到细胞核中调节炎症基因转录所必需的。在此资助期内，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细胞重新定向中的作用，2.确定cofilin核易位的机制及其在调节基因表达中的作用，3.确定Nox4/cofilin通路在减轻体内高血压引起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此类刺激对细胞表型的影响的理解，提供足够的原理证明来支持新治疗方法的识别 目标。