Regulation of Endothelial ICAM-1 and PMN-Mediated Lung Injury by Actin Dynamics

肌动蛋白动力学对内皮 ICAM-1 和 PMN 介导的肺损伤的调节

• 批准号: 8235015
• 负责人: Fabeha Fazal
• 金额: $ 30.59万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2015-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8235015
• 关键词: Actin-Binding Protein; Actins; Acute Lung Injury; Address; Adhesions; Adhesives; Adult Respiratory Distress Syndrome; Binding; Biochemical; Blood Vessels; Cell Nucleus; Cell surface; Coagulation Process; Cytoplasm; Cytoskeleton; Data; Development; Disease; Edema; Emigrations; Endothelial Cells; Endothelium; Event; Genetic; ICAM1 gene; Immigration; Infiltration; Inflammation; Inflammatory; Injury; Intercellular adhesion molecule 1; LIM Domain Kinase 1; Lead; Lung; MYLK gene; Mediating; Modeling; Molecular and Cellular Biology; Mus; Myosin ATPase; Myosin Light Chain Kinase; Myosin Type II; Nonmuscle Myosin Type IIA; Nuclear; Nuclear Import; Nuclear Translocation; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiology; Play; Positioning Attribute; Proteins; Public Health; Regulation; Role; Secondary to; Sepsis; Serine Protease; Signal Transduction; Testing; Thrombin; Tissues; base; cofilin; depolymerization; in vivo; insight; interdisciplinary approach; intraperitoneal; lung injury; lung vascular injury; migration; mouse model; neutrophil; novel; nucleocytoplasmic transport; p65; prevent; promoter; public health relevance; trafficking; transcription factor; uptake

DESCRIPTION (provided by applicant): The overall objective of the proposed studies is to address the mechanisms by which thrombin, a serine protease released during clotting initiated by sepsis or vascular injury, regulates the expression of adhesive protein intercellular adhesion molecule-1 (ICAM-1; CD54) in endothelial cells, and how this event promotes sequestration and migration of polymorphonuclear leukocytes (PMN) in the lung and thus contributes to development of lung vascular injury. The basis of ICAM-1 expression involves activation of RelA/p65 subunit of the transcription factor NF-(B. Activation of RelA/p65 requires its release from the inhibitory protein I(B( in the cytoplasm and subsequently, its translocation to the nucleus. Whereas the mechanisms of its release have been elucidated, the cytoplasmic events regulating the translocation of RelAp65 to the nucleus remain elusive. We previously showed that activation of RhoA/ROCK and the dynamic changes in actin cytoskeleton induced by thrombin are crucial for NF-(B activation and ICAM-1 expression. We now have evidence that cofilin, an actin binding protein that promotes actin depolymerization, occupies a central position in RhoA-actin pathway mediating ICAM-1 expression by virtue of facilitating the nuclear translocation of RelA/p65. Interestingly, LIM kinase 1 (LIMK1), a cofilin kinase, and slingshot (SSH1L), a cofilin phosphatase, also regulate ICAM-1 expression. Additionally, MLCK and its target myosin IIA play an important role in thrombin-induced NF-(B activation. Based upon these findings, we hypothesize that thrombin engages LIMK1 and SSH1L as well as MLCK to regulate actin-myosin interaction, which in turn facilitates nuclear translocation of RelA/p65, and expression of ICAM-1 in endothelial cells. We will also test the hypothesis that MLCK signaling of ICAM-1-dependent endothelial adhesivity by this mechanism contributes to lung PMN sequestration and PMN-mediated lung vascular injury and tissue edema in mice. We will pursue the following specific aims to test this hypothesis. Specific Aim 1 will determine the role of LIMK1 and SSH1L in regulating the changes in the actin cytoskeleton leading to nuclear translocation of RelA/p65 and expression of ICAM-1 in endothelial cells. Specific Aim 2 will address the role of MLCK in regulating actin-myosin interaction leading to nuclear transport of RelA/p65 and expression of ICAM-1 in endothelial cells. Specific Aim 3 will evaluate the in vivo role of endothelial MLCK in regulating thrombin-induced ICAM-1 expression, lung PMN infiltration, and PMN-mediated lung vascular injury in mice. We will use multidisciplinary approaches ranging from biochemical, cellular, and molecular biology to lung physiology to carry out these studies. With the information gained, we believe that it will be possible to block PMN-mediated lung vascular injury by inhibiting the specific signaling events controlling ICAM-1 expression associated with intravascular coagulation and consequent inflammation. PUBLIC HEALTH RELEVANCE: These studies will provide novel insights into the mechanisms regulating translocation of RelA/p65 into the nucleus and thereby expression of ICAM-1, and its consequences on lung PMN sequestration and lung vascular injury. The information gained may lead to the development of strategies for interfering with specific signaling events controlling ICAM-1 expression and thereby preventing or limiting lung PMN uptake and lung vascular injury associated with inflammatory disease states as Acute Respiratory Distress Syndrome (ARDS).

描述（由申请方提供）：拟定研究的总体目标是阐明凝血酶（一种在脓毒症或血管损伤引发的凝血过程中释放的丝氨酸蛋白酶）调节粘附蛋白细胞间粘附分子-1表达的机制（ICAM-1; CD54），以及该事件如何促进多形核白细胞（PMN）在肺中的隔离和迁移，从而促进肺血管损伤的发展。ICAM-1表达的基础涉及转录因子NF-（B. RelA/p65的激活需要其从细胞质中的抑制性蛋白I（B）释放，随后，其易位到细胞核。尽管其释放机制已得到阐明，但调节RelAp 65转运至细胞核的细胞质事件仍然难以捉摸。我们先前的研究表明凝血酶诱导的RhoA/ROCK的激活和肌动蛋白细胞骨架的动态变化对NF-β B的激活和ICAM-1的表达至关重要。我们现在有证据表明，cofilin，一种促进肌动蛋白解聚的肌动蛋白结合蛋白，在RhoA-肌动蛋白通路中占据中心位置，通过促进RelA/p65的核转位介导ICAM-1的表达。有趣的是，LIM激酶1（LIMK 1），一种cofilin激酶，和弹弓（SSH 1 L），一种cofilin磷酸酶，也调节ICAM-1的表达。此外，MLCK及其靶肌球蛋白IIA在凝血酶诱导的NF-（B）活化中起重要作用。基于这些发现，我们推测凝血酶参与LIMK 1和SSH 1 L以及MLCK调节肌动蛋白-肌球蛋白相互作用，这反过来又促进RelA/p65的核转位，以及ICAM-1在内皮细胞中的表达。我们还将测试的假设，即MLCK信号的ICAM-1依赖的内皮细胞粘附性，通过这种机制有助于肺中性粒细胞隔离和中性粒细胞介导的肺血管损伤和组织水肿的小鼠。我们将追求以下具体目标来检验这一假设。具体目标1将确定LIMK 1和SSH 1 L在调节肌动蛋白细胞骨架的变化中的作用，从而导致RelA/p65的核转位和内皮细胞中ICAM-1的表达。具体目标2将阐明MLCK在调节肌动蛋白-肌球蛋白相互作用中的作用，从而导致RelA/p65的核转运和内皮细胞中ICAM-1的表达。具体目标3将评估内皮MLCK在调节凝血酶诱导的ICAM-1表达、肺PMN浸润和PMN介导的小鼠肺血管损伤中的体内作用。我们将使用多学科的方法，从生物化学，细胞和分子生物学肺生理学进行这些研究。根据所获得的信息，我们相信通过抑制与血管内凝血和随后的炎症相关的控制ICAM-1表达的特异性信号事件，将有可能阻断PMN介导的肺血管损伤。 公共卫生相关性：这些研究将提供新的见解的机制，调节RelA/p65易位到核，从而ICAM-1的表达，其后果对肺中性粒细胞隔离和肺血管损伤。所获得的信息可能导致开发用于干扰控制ICAM-1表达的特定信号传导事件的策略，从而预防或限制与急性呼吸窘迫综合征（ARDS）等炎性疾病状态相关的肺PMN摄取和肺血管损伤。