Microvascular Dysfunction: Impact Ischemia-Reperfusion Vascular Cell Interaction

微血管功能障碍：影响缺血再灌注血管细胞相互作用

• 批准号: 7918618
• 负责人: RONALD JOHN KORTHUIS
• 金额: $ 36.22万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-22 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7918618
• 关键词: Address; Adherence; Adhesions; Adhesives; Angiotensin II; Angiotensins; Animal Model; Animals; Arteries; Blood Vessels; Blood flow; Brain; Caliber; Cause of Death; Cell Adhesion Molecules; Cell Communication; Cell Degranulation; Cells; Chymase; Coupling; Development; Dilator; Emigrations; Endothelial Cells; Endothelium; Event; Extracellular Matrix; Functional disorder; Gelatinase B; Generations; Goals; Heart; Integrins; Intestines; Ischemia; Ischemic Bowel Disease; Kidney; Leukocyte Rolling; Leukocytes; Link; Lymph; Mediating; Microscopic; Modeling; Molecular; Mus; Oxidants; Oxidases; Pathogenesis; Pathway interactions; Peptide Hydrolases; Play; Production; Rattus; Reaction; Reactive Oxygen Species; Reagent; Reperfusion Therapy; Role; Signal Transduction; Site; Source; Superoxides; Tissues; Transgenic Animals; Vascular blood supply; Vasodilation; Work; arteriole; design; disability; interstitial; knockout gene; mast cell; neutrophil; novel; novel therapeutic intervention; postcapillary venule; prevent; response

Ischemia/reperfusion (I/R) induces leukoeyte/endothelial cell adhesive interactions (LECA) in postcapillary venules and impaired endothelium-dependent, NO-mediated vasodllatory responses (EDD) in upstream arterioles. Even though leukocytes do not roll along, adhere to, or emigrate across arteriolar endothelium in postischemic intestine, recent work indicates that l/R-induced venular LECA is causally linked to EDD in arterioles. However, the mechanisms coupling l/R-induced postcapillary venular LECA and EDD in upstream arterioles are unknown. Our overall hypothesis is that l/R-induced EDD in arterioles occurs by a mechanism that is triggered by LECA in postcapillary venules and involves the formation of signals in the interstitium elicited by the proteolytic activity of emigrated leukocytes which exposes matricryptic sites in the extracellular matrix (ECM) that interact with the integrin avp3 to induce mast cell-dependent formation of angiotensin II (Ang II). Subsequent activation of NAD(P)H oxidase promotes eNOS uncoupling in the vascular wall and leads to the formation of oxidants which inactivate NO, resulting in arteriolar EDD. Our Specific Aims are to determine: Aim A) whether venular LECA play an obligatory role in the development of EDD in upstream arterioles; Aim B) the contribution of leukocyte-derived proteases to the development of arteriolar EDD; Aim C) the role of avp3 integrin in initiating chymase-dependent formafion of Ang II; and Aim D) the role of Ang ll-dependent, NAD(P)H oxidase- and uncoupled eNOS-mediated oxidant production in arteriolar EDD. Intravital microscopic approaches will be used to examine arteriolar EDD, venular LECA, and mast cell responses to I/R. Arterioles will be isolated from non-ischemic intesfine and exposed to posfischemic lymph, as a means to examine interstitial signals that are generated by the proteolytic acfivity of extravasated leukocytes. A novel three-dimensional ECM model engrafted with isolated cannulated arterioles and seeded with mast cells in the presence and absence of neutrophils will also be used to to further explore our hypothesis. Isolated arterioles obtained from a number of gene knockout and transgenic animal models will be used to further explore the mechanisms of arteriolar EDD. Collectively, these aims address a novel mechanism to explain the profound disturbance in arteriolar vasoregulatory funcfion in postischemic tissues. Significance: This work will identify new links between LECA in postcapillary venules, signals generated in the interstitium by emigrated leukocytes, and EDD in arterioles. Given the importance of the endothelium in regulating vascular tone, these fundamentally important findings have enormous implications for our understanding of blood flow dysregulation in conditions characterized by I/R.

缺血/再灌注（I/R）诱导毛细血管后白细胞/内皮细胞粘附相互作用（LECA） 微静脉和上游内皮依赖性、NO 介导的血管舒张反应 (EDD) 受损 小动脉。尽管白细胞不会沿着小动脉内皮滚动、粘附或迁移 缺血后肠道，最近的研究表明，L/R 诱导的小静脉 LECA 与 EDD 存在因果关系 小动脉。然而，l/R 诱导的毛细血管后小静脉 LECA 和上游 EDD 的耦合机制 小动脉未知。我们的总体假设是，L/R 诱导的小动脉 EDD 是由 毛细血管后微静脉中的 LECA 触发的机制，涉及在毛细血管中形成信号 由迁移的白细胞的蛋白水解活性引起的间质，暴露了基质中的基质隐位点 细胞外基质 (ECM) 与整合素 avp3 相互作用，诱导肥大细胞依赖性形成 血管紧张素II（Ang II）。随后 NAD(P)H 氧化酶的激活促进 eNOS 解偶联 血管壁并导致形成氧化剂，使 NO 失活，导致小动脉 EDD。我们的 具体目标是确定： 目标 A) 静脉 LECA 是否在 上游小动脉的 EDD；目标 B) 白细胞来源的蛋白酶对细胞发育的贡献 动脉EDD；目标C) avp3整合素在启动胃促胰酶依赖性Ang II形成中的作用；和目标 D) Ang II 依赖性、NAD(P)H 氧化酶和非偶联 eNOS 介导的氧化剂产生在 动脉 EDD。活体显微镜方法将用于检查小动脉 EDD、小静脉 LECA、 和肥大细胞对 I/R 的反应。将从非缺血性肠中分离出小动脉并暴露于 缺血后淋巴，作为检查蛋白水解活性产生的间质信号的一种手段 外渗的白细胞。一种植入隔离空心管的新型三维 ECM 模型 小动脉并在存在和不存在中性粒细胞的情况下接种肥大细胞也将用于进一步探索我们的假设。从多个基因敲除和转基因动物模型中获得的分离小动脉将用于进一步探索小动脉EDD的机制。总的来说，这些目标提出了一种新机制来解释缺血后组织中小动脉血管调节功能的严重紊乱。意义：这项工作将确定毛细血管后微静脉中的 LECA、迁移的白细胞在间质中产生的信号以及小动脉中的 EDD 之间的新联系。鉴于内皮细胞在调节血管张力方面的重要性，这些具有根本意义的重要发现具有巨大的意义。 对我们理解以 I/R 为特征的情况下血流失调的影响。