The splenic CD4+ T cells mediate myocardial ischemia-reperfusion injury

脾CD4 T细胞介导心肌缺血再灌注损伤

• 批准号: 9249963
• 负责人: ZEQUAN YANG
• 金额: $ 39.5万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9249963
• 关键词: Accounting; Acute; Adenosine; Adoptive Transfer; Agonist; Binding; Biomedical Research; Blood; Blood Circulation; Blood flow; Brain; CD4 Positive T Lymphocytes; Cardiac; Cause of Death; Cells; Cessation of life; Collection; Complex; Coronary; DNA-Binding Proteins; Data; Deoxyribonuclease I; Genes; HMGB1 Protein; HMGB1 gene; Heart; Heart failure; Hour; Individual; Infarction; Inflammatory; Inflammatory Response; Injury; Ischemia; Kidney; Leukocytes; Liposomes; Lymphocyte; Mediating; Mitochondrial DNA; Molecular; Monoclonal Antibodies; Mononuclear; Morbidity - disease rate; Mus; Myocardial; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion; Myocardial Reperfusion Injury; Myocardial tissue; Necrosis; Neutrophil Activation; Neutrophil Infiltration; Organ; Outcome; Pathway interactions; Pattern; Phase; Plasma; Play; Population; Procedures; Process; Publishing; Reperfusion Injury; Reperfusion Therapy; Reporting; Research Project Grants; Role; Spleen; Splenectomy; Splenocyte; System; TLR9 gene; Testing; Therapeutic; Tissues; United States; Ventricular Remodeling; Work; base; experimental study; monocyte; mortality; mouse model; myocardial infarct sizing; neutrophil; public health relevance; receptor; receptor for advanced glycation endproducts; targeted delivery; treatment strategy

 DESCRIPTION (provided by applicant): Accumulating evidence suggests that CD4+ T cells mediate neutrophil recruitment and organ injury during ischemia and reperfusion (I/R). However, the precise mechanisms by which CD4+ T cell populations, circulating or tissue resident CD4+ T cells, contribute to myocardial I/R injury are not fully understood. A role of the spleen in mediating I/R injury has been reported in the kidney and brain. But, the role of spleen in mediating inflammatory response during acute phase of myocardial reperfusion injury remains unknown. Previous studies related to the spleen are concentrated on role of the spleen, especially the splenic mononuclear cells, on post-MI remodeling and later phase (>24 hours of reperfusion) of I/R injury. Different from post-MI remodeling, we found that during acute phase of post-ischemic reperfusion, circulating lymphocytes and monocytes are decreased. The myocardial infarct size finalized within one hour of reperfusion versus 24 hours of reperfusion. Thus, inflammatory response within one-hour reperfusion is more critical in causing myocardial tissue necrosis. Our preliminary study has shown that substances, HMGB1 and mitochondrial DNA (mtDNA), were released from the ischemic myocardium and activated splenocytes upon reperfusion by acting on RAGE and/or possible TLR9 receptors. Splenectomy before I/R reduced myocardial infarct size. Acute adoptive transfer of normal splenocytes into the bloodstream of the splenectomized mice restored infarct size to that of control mice. These results indicate that the spleen plays a central role in myocardial I/R injury via HMGB1/mtDNA−RAGE/TLR9 pathway. We therefore hypothesize that splenic CD4+ T cells are activated via a cardio-splenic axis during reperfusion and contribute importantly to myocardial I/R injury. To test these hypotheses, we will first determine the role of splenic CD4+ T cells in myocardial I/R injury by using WT mice with or without splenectomy in combination with adoptive transfer of splenocytes from WT, RAGE-/- and CD4-/- mice. Following these experiments, we will test that infarct-sparing effect of an A2AR agonist is due to its action on A2ARs of splenic CD4+ T cells and will develop a liposome system to deliver the A2AR agonist to the spleen to inhibit the splenic leukocytes. Secondly, we will determine that a cardio-splenic axis causes I/R injury via a HMGB1/mtDNA (from ischemic myocardium) - RAGE/TLR9 (on splenic CD4+ T cells) pathway. We will employ a mouse model with shorter I/R, 20-min ischemia and 60-min reperfusion and treat mice with ischemic heart homogenates (IHH) or coronary perfusate (CP) from mice with 40-min ischemia and plasma acquired at 5-min reperfusion. The HMGB1 and/or mtDNA in IHH, CP or plasma will activate splenic CD4+ T cells by either binding to RAGEs or to TLR9 receptors and exacerbate infarct size. Finally, we will determine if the therapeutic blockade of HMGB1 or mtDNA in the blood will suffice to block the cardio-splenic axis, reduce myocardial infarct size and preserve cardiac function.

 描述（由申请人提供）：越来越多的证据表明，CD 4 + T细胞介导缺血和再灌注（I/R）期间的中性粒细胞募集和器官损伤。然而，CD 4 + T细胞群，循环或组织驻留的CD 4 + T细胞，有助于心肌I/R损伤的确切机制尚未完全了解。脾在介导肾和脑I/R损伤中的作用已被报道。但是，脾脏在心肌再灌注损伤急性期介导炎症反应中的作用尚不清楚。先前与脾相关的研究集中于脾，特别是脾单核细胞在MI后重构和I/R损伤的后期（>24小时再灌注）中的作用。与心肌梗死后重构不同的是，我们发现在缺血再灌注后急性期，循环中的淋巴细胞和单核细胞减少。心肌梗死面积在再灌注1小时内与再灌注24小时内最终确定。因此，再灌注1小时内的炎症反应在引起心肌组织坏死方面更为关键。我们的初步研究表明，物质，HMGB 1和线粒体DNA（mtDNA），从缺血心肌释放和激活脾细胞再灌注后，通过作用于β受体和/或可能的TLR 9受体。I/R前脾切除可减少心肌梗死面积。将正常脾细胞急性过继转移到脾切除小鼠的血流中，使梗死面积恢复到对照小鼠的梗死面积。这些结果表明，脾脏通过HMGB 1/mtDNA-κ B/TLR 9途径在心肌I/R损伤中发挥核心作用。因此，我们假设脾脏CD 4 + T细胞在再灌注过程中通过心脾轴被激活，并对心肌I/R损伤有重要作用。为了检验这些假设，我们将首先通过使用有或没有脾切除术的WT小鼠结合过继转移来自WT、CD 4-/-和CD 4-/-小鼠的脾细胞来确定脾CD 4 + T细胞在心肌I/R损伤中的作用。在这些实验之后，我们将测试A2 AR激动剂的梗塞保留效应是由于其对脾CD 4 + T细胞的A2 AR的作用，并且将开发脂质体系统以将A2 AR激动剂递送至脾以抑制脾白细胞。其次，我们将确定心脏-脾脏轴通过HMGB 1/mtDNA（来自缺血心肌）-HMGB 1/TLR 9（脾脏CD 4 + T细胞）途径引起I/R损伤。我们将采用I/R时间较短、缺血20分钟和再灌注60分钟的小鼠模型，并用缺血40分钟小鼠的缺血心脏匀浆（IHH）或冠状动脉灌注液（CP）和5分钟再灌注时获得的血浆治疗小鼠。IHH、CP或血浆中的HMGB 1和/或mtDNA将通过与RAGE或TLR 9受体结合而激活脾CD 4 + T细胞，并加剧梗死面积。最后，我们将确定血液中HMGB 1或mtDNA的治疗性阻断是否足以阻断心脾轴，减少心肌梗死面积并保护心脏功能。