The Endothelial Glycocalyx: Its Structure and Function and as a Mechanotransducer

内皮糖萼：其结构和功能以及作为机械传感器

• 批准号: 8056011
• 负责人: JOHN M TARBELL
• 金额: $ 55.79万
• 依托单位: CITY COLLEGE OF NEW YORK
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-15 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8056011
• 关键词: Address; Adhesions; Amino Acid Sequence; Aorta; Atherosclerosis; Binding; Biomedical Engineering; Blood Vessels; Blood flow; Caveolae; Cell Line; Cells; Characteristics; Chondroitinases; Complement; Confocal Microscopy; Core Protein; Cytoskeleton; Dehydration; Diabetes Mellitus; Disease; Electron Microscopy; Endothelial Cells; Enzymes; Epoprostenol; Event; Focal Adhesions; Functional disorder; Glycocalyx; Glycosaminoglycans; Glypican; Goals; Gold; Health; Heparan Sulfate Proteoglycan; Heparin Lyase; Heparitin Sulfate; Hyaluronic Acid; Hyaluronidase; Hypertension; In Vitro; Inorganic Sulfates; Knowledge; Label; Liquid substance; Mediating; Membrane; Methods; Microscopy; Molecular Biology; Morphologic artifacts; Mus; Neuraminidase; Nitric Oxide; Plasma Proteins; Process; Production; Prostaglandins I; Proteins; Proteoglycan; Public Health; RNA Interference; Research; Research Project Grants; Series; Sialic Acids; Signaling Molecule; Structure; Surface; Technology; Thick; Time; Transmission Electron Microscopy; Unspecified or Sulfate Ion Sulfates; Vascular Diseases; Vasodilator Agents; Work; combat; in vivo; insight; knockout animal; macromolecule; proteoglycan core protein; public health relevance; research study; response; shear stress; small hairpin RNA; syndecan

DESCRIPTION (provided by applicant): The luminal surfaces of endothelial cells (ECs) that line our vasculature are coated with a glycocalyx of membrane-bound macromolecules comprised of sulfated proteoglycans, hyaluronic acid, sialic acids, glycocproteins and plasma proteins that adhere to this surface matrix. The endothelial glycocalyx layer (EGL) provides a multifunctional coating to the vasculature that is degraded in disease states such as atherosclerosis and diabetes. Because of dehydration artifacts associated with conventional electron microscopy, even such rudimentary characteristics as the thickness of the layer have not been firmly established. In vivo and in vitro studies have, however, shown that heparan sulfate proteoglycans mediate endothelial remodeling (cell elongation and alignment) in response to fluid shear stress and along with hyaluronic acid control vital mechanotransduction events such as fluid shear-induced stimulation of nitric oxide production, but the core proteins that are involved in these characteristic responses are not known. To address these fundamental questions that are crucial for our understanding of vascular function in health and disease, we will pursue the following studies in the proposed research: To elucidate the structure of the endothelial glycocalyx layer (EGL) we will apply, for the first time, cryo-transmission electron microscopy (cryo-TEM) in conjunction with confocal microscopy to determine its thickness and organization. To determine the proteoglycan core proteins that mediate EC remodeling and mechanotransduction in response to fluid shear stress we will use glycosaminoglycan (GAG) degrading enzymes, RNA interference technology and adhesion blocking amino acid sequences in vitro and knockout animals in vivo to deconstruct these processes. To carry out the projects in this Bioengineering Research Grant (BRG), we have organized a research team with core expertise in bioengineering including: in vitro shear experiments (Tarbell), and in vivo shear experiments (Fu) that is complemented by expertise in microscopy and molecular biology (Spray). PUBLIC HEALTH RELEVANCE: The research is important to public health because the endothelial glycocalyx layer (EGL) provides a multifunctional coating to the vasculature that is degraded in disease states such as atherosclerosis and diabetes. Degradation of the EGL leads to vasoregulatory dysfunction through, for example, loss of blood flow-induced stimulation of the potent vasodilator, nitric oxide. Knowledge of EGL structure and the core proteins and glycosaminoglycans involved in mechanotransduction/remodeling will be required if methods are to be developed to re-constitute or reinforce the EGL. A re-constituted EGL will restore critical vasoregulatory functions, thus combating disease. The foundational work proposed in this application is essential for translational work that will follow as part of the long range goals of this project.

描述（由申请人提供）：我们的血管系统中的内皮细胞（EC）的管腔表面包被有膜结合大分子的糖萼，该糖萼由硫酸化蛋白聚糖、透明质酸、唾液酸、糖蛋白和血浆蛋白组成，粘附在该表面基质上。内皮糖萼层（EGL）为血管系统提供多功能涂层，其在诸如动脉粥样硬化和糖尿病的疾病状态下降解。由于与常规电子显微镜相关的脱水伪影，甚至层的厚度这样的基本特征也没有被牢固地建立。然而，体内和体外研究表明，硫酸乙酰肝素蛋白聚糖介导内皮重塑（细胞伸长和排列），以响应流体剪切应力，并沿着与透明质酸控制重要的机械转导事件，如流体剪切诱导的刺激一氧化氮的产生，但参与这些特征性反应的核心蛋白是未知的。为了解决这些对于我们理解健康和疾病中的血管功能至关重要的基本问题，我们将在拟议的研究中进行以下研究：为了阐明内皮糖萼层（EGL）的结构，我们将首次应用冷冻透射电子显微镜（cryo-TEM）结合共聚焦显微镜来确定其厚度和组织。为了确定介导EC重塑和机械转导的蛋白聚糖核心蛋白，以响应流体剪切应力，我们将使用糖胺聚糖（GAG）降解酶，RNA干扰技术和粘附阻断氨基酸序列在体外和敲除动物在体内解构这些过程。 为了开展这项生物工程研究资助（BRG）中的项目，我们组织了一个具有生物工程核心专业知识的研究团队，包括：体外剪切实验（Tarbell）和体内剪切实验（Fu），并辅以显微镜和分子生物学（Spray）的专业知识。 公共卫生相关性：这项研究对公共卫生很重要，因为内皮糖萼层（EGL）为血管系统提供了多功能涂层，该涂层在动脉粥样硬化和糖尿病等疾病状态下会降解。EGL的降解导致血管调节功能障碍，例如，通过丧失血流诱导的有效血管扩张剂一氧化氮的刺激。如果要开发重建或加强EGL的方法，则需要了解EGL结构和参与机械传导/重塑的核心蛋白和糖胺聚糖。重建的EGL将恢复关键的血管调节功能，从而对抗疾病。本申请中提出的基础工作对于作为本项目长期目标一部分的翻译工作至关重要。