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Vascular protection via alpha5beta1 integrin inhibition during neuroinflammation

神经炎症期间通过 α5β1 整合素抑制实现血管保护

基本信息

批准号：
9201336
负责人：
Gregory Jaye Bix
金额：
$ 23.01万
依托单位：
SCRIPPS RESEARCH INSTITUTE, THE
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-15 至 2018-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9201336
关键词：
Animal Model Biological Assay Blood - brain barrier anatomy Blood Vessels Cell Adhesion Molecules Cell Surface Receptors Cerebrum Chronic Clinical Demyelinating Diseases Demyelinations Disease Dose Endothelial Cells Experimental Autoimmune Encephalomyelitis Extracellular Matrix Proteins Fibronectins Flow Cytometry Genetic Goals Histology Human Hypoxia Immunofluorescence Immunologic In Vitro Infarction Infiltration Inflammatory Integrin Inhibition Integrin alpha5 Integrin alpha5beta1 Integrins Intercellular adhesion molecule 1 Ischemic Stroke Knockout Mice Leukocytes Ligands Maintenance Malignant Neoplasms Modeling Molecular Multiple Sclerosis Neuraxis Pathogenesis Peptides Permeability Pharmacology Property Proteins Resistance Stroke TNF gene Testing Tight Junctions Transgenic Mice Treatment Efficacy Vascular Cell Adhesion Molecule-1 Vascular remodeling Western Blotting Wild Type Mouse angiogenesis axonal degeneration brain endothelial cell brain parenchyma cerebrovascular cytokine experimental study inhibitor/antagonist leukocyte homing monolayer neuroinflammation novel public health relevance receptor response therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Multiple sclerosis (MS) is a chronic inflammatory disease characterized by demyelination and degeneration of axons in the central nervous system (CNS). Compelling evidence suggests that breakdown of the blood-brain barrier (BBB) and angiogenic remodeling occur at an early stage of MS as well as in the animal model of MS, experimental autoimmune encephalomyelitis (EAE), and is central to the initiation and maintenance of disease pathogenesis by affording leukocyte infiltration into the brain parenchyma. This vascular remodeling, in turn, is strongly influenced by the interaction between extracellular matrix (ECM) proteins and their endothelial integrin cell surface receptors. In particular, the α5β1 integrin and its ligand fibronectin are strongly upregulated on remodeling cerebral vessels in animal models of ischemic stroke and MS, and transgenic mice lacking this receptor in endothelial cells (α5-EC-KO mice) show delayed and reduced angiogenic remodeling in response to hypoxia. Furthermore, our recent studies in an experimental stroke model showed that α5-EC-KO mice are profoundly resistant to BBB breakdown, resulting in dramatic reductions in size of ischemic infarct. Pharmacological blockade of α5β1 integrin in wild-type (WT) mice achieved similar protection. As BBB breakdown and angiogenesis occur at an early stage of MS and EAE, and current evidence suggests that the α5β1 integrin is an important trigger of cerebrovascular remodeling, we hypothesize that inhibition of endothelial α5β1 integrin stabilizes the BBB and reduces leukocyte infiltration in demyelinating disease. In support of this hypothesis, new preliminary results suggest that pharmacological blockade of α5β1 integrin in cultured WT brain endothelial cells stabilizes their barrier properties in presece of the barrier-disrupting inflammatory cytokine TNF-α. These studies also suggested that protection may be a result of increased expression of claudin-5, a tight junction protein and critical component of the BBB. Armed with these results, we propose the following specific aims: (1) determine whether genetic deletion or pharmacological blockade of α5β1 integrin on endothelial cells stabilizes the BBB, resulting in reduced neuroinflammation and demyelination in the EAE model, and 2) determine the molecular mechanism whereby α5β1 integrin inhibition promotes BBB integrity and subsequent resistance to EAE. We expect to demonstrate that inhibition of α5β1 integrin in endothelial cells confers robust resistance to EAE by increasing BBB integrity through stabilization of tight junction proteins and suppression of the leukocyte- homing adhesion molecules ICAM-1 and VCAM-1. Successful completion of these studies will further our goal of developing endothelial α5β1 integrin as a novel MS therapeutic target.

描述（由申请人提供）：多发性硬化症（MS）是一种慢性炎症性疾病，其特征是中枢神经系统（CNS）中轴突脱髓鞘和变性。令人信服的证据表明，血脑屏障 (BBB) 的破坏和血管生成重塑发生在 MS 的早期阶段以及 MS 动物模型、实验性自身免疫性脑脊髓炎 (EAE) 中，并且通过提供白细胞浸润到脑实质中，对于疾病发病机制的启动和维持至关重要。反过来，这种血管重塑受到细胞外基质（ECM）蛋白与其内皮整合素细胞表面受体之间相互作用的强烈影响。特别是，在缺血性中风和多发性硬化症动物模型中，α5β1整合素及其配体纤连蛋白在脑血管重塑中强烈上调，而内皮细胞中缺乏这种受体的转基因小鼠（α5-EC-KO小鼠）表现出响应缺氧的延迟和减少的血管生成重塑。此外，我们最近对实验性中风模型的研究表明，α5-EC-KO 小鼠对 BBB 破坏有很强的抵抗力，从而导致缺血性梗塞面积急剧减小。在野生型 (WT) 小鼠中对 α5β1 整合素进行药理学阻断也达到了类似的保护作用。由于 BBB 破坏和血管生成发生在 MS 和 EAE 的早期阶段，并且目前的证据表明 α5β1 整合素是脑血管重塑的重要触发因素，因此我们假设抑制内皮 α5β1 整合素可以稳定 BBB 并减少脱髓鞘疾病中的白细胞浸润。为了支持这一假设，新的初步结果表明，在培养的 WT 脑内皮细胞中，对 α5β1 整合素进行药理学阻断，可以在破坏屏障的炎症细胞因子 TNF-α 之前稳定其屏障特性。这些研究还表明，保护作用可能是 Claudin-5 表达增加的结果，claudin-5 是一种紧密连接蛋白，也是 BBB 的关键成分。有了这些结果，我们提出以下具体目标：（1）确定内皮细胞上α5β1整合素的遗传删除或药理学阻断是否可以稳定BBB，从而减少EAE模型中的神经炎症和脱髓鞘，2）确定α5β1整合素抑制促进BBB完整性和随后对EAE的抵抗的分子机制。我们希望证明，通过稳定紧密连接蛋白和抑制白细胞归巢粘附分子 ICAM-1 和 VCAM-1 来增强 BBB 完整性，抑制内皮细胞中的 α5β1 整合素可赋予对 EAE 的强大抵抗力。这些研究的成功完成将进一步推动我们将内皮 α5β1 整合素开发为新型多发性硬化症治疗靶点的目标。