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: 9121815
• 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/9121815
• 关键词: ADORA2A gene; 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 receptor; 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 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; T-Cell Activation; TLR9 gene; Testing; Therapeutic; Tissues; United States; Ventricular Remodeling; Work; base; monocyte; mortality; mouse model; myocardial infarct sizing; neutrophil; public health relevance; receptor; receptor for advanced glycation endproducts; research study; 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（由适用提供）：累积证据表明CD4+ T细胞在缺血和再灌注期间介导中性粒细胞募集和器官损伤（I/R）。然而，尚不完全了解CD4+ T细胞群体，循环或组织居民CD4+ T细胞的确切机制尚不完全了解心肌I/R损伤。在肾脏和大脑中报道了脾脏在介导I/R损伤中的作用。但是，在心肌再灌注损伤的急性阶段，SLEN在介导炎症反应中的作用仍然未知。先前与SLEEN相关的研究集中在Sleen的作用上，尤其是脾脏单核细胞，在MI重塑后以及I/R损伤的后期（> 24小时的再灌注）中（> 24小时）。与MI后重塑不同，我们发现在缺血后再灌注的急性期，循环淋巴细胞和单核细胞降低。心肌梗塞大小在再灌注后一小时内最终确定，而再灌注24小时。一小时再灌注中的炎症反应对于引起心肌组织坏死更为重要。我们的初步研究表明，物质HMGB1和线粒体DNA（mtDNA）通过缺血性心肌从缺血性心肌释放出来，并通过对愤怒和/或可能的TLR9受体作用而在再灌注后激活脾细胞。 I/R之前的脾切除术减少了心肌基础设施的大小。将正常脾细胞急性自适应转移到脾脏小鼠的血液中，将基础设施大小恢复到对照小鼠的大小。这些结果表明，脾脏通过HMGB1/mtDNA-RAGE/TLR9途径在心肌I/R损伤中起着核心作用。 We therefore hypothesize that splenic CD4+ T cells are activated via a cardio-splenic axis during reperfusion and contribute importantly 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 splenic in combination with adaptive transfer of splenocytes from WT, RAGE-/- and CD4-/- mice.在这些实验之后，我们将测试A2AR激动剂的梗死效应是由于其对脾脏CD4+ T细胞A2AR的作用所致，并将开发出脂质体系统，以将A2AR激动剂传递到脾脏以抑制脾脏白细胞。其次，我们将确定心形轴通过HMGB1/mtDNA（来自缺血性心肌） - RAGE/TLR9（在脾脏CD4+ T细胞）途径中引起I/R损伤。我们将采用一种小鼠模型，具有较短的I/R，20分钟的缺血和60分钟的再灌注，并用缺血性心脏匀浆（IHH）或冠状动脉灌注酸盐（CP）处理小鼠，该小鼠的小鼠局部缺血40分钟，血浆以5分钟的再灌注获得。 IHH，CP或血浆中的HMGB1和/或mtDNA将通过与rage或TLR9受体结合并加剧基础结构大小来激活脾CD4+ T细胞。最后，我们将确定血液中HMGB1或mtDNA的治疗性阻滞是否足以阻止心形轴轴，减少心肌基础设施大小并保留心脏功能。