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

基本信息

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
项目类别：
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

项目摘要

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，CD4+ T 细胞在缺血和再灌注 (I/R) 过程中介导中性粒细胞募集和器官损伤，然而，CD4+ T 细胞群、循环或驻留组织 CD4+ T 细胞的确切机制，目前尚未完全了解脾脏在介导 I/R 损伤中的作用，但在肾脏和大脑中的作用已被报道。脾脏在心肌再灌注损伤急性期介导炎症反应的作用尚不清楚，之前与脾脏相关的研究主要集中在脾脏，特别是脾脏单核细胞在心肌梗死后重塑和后期（再灌注> 24小时）中的作用。与心肌梗死后重塑不同，我们发现在缺血再灌注后的急性期，循环淋巴细胞和单核细胞减少。再灌注一小时内与再灌注 24 小时内确定心肌梗死面积因此，再灌注一小时内的炎症反应对于引起心肌组织坏死更为关键。在 I/R 之前，通过作用于 RAGE 和/或可能的 TLR9 受体，从缺血心肌中释放出来，并在再灌注时激活脾细胞。正常脾细胞急性过继性转移至脾切除小鼠的血流中，使梗塞面积恢复至对照小鼠的水平。这些结果表明，脾脏通过 HMGB1/mtDNA−RAGE/ 在心肌 I/R 损伤中发挥着核心作用。因此，我们努力研究脾 CD4+ T 细胞在再灌注过程中通过心脾轴被激活，并对 TLR9 通路发挥重要作用。为了检验这些假设，我们首先使用有或没有脾切除的 WT 小鼠结合来自 WT、RAGE-/- 的脾细胞过继转移来确定脾 CD4+ 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 A2AR 激动剂的梗塞保留作用是由于其对脾脏 A2AR 的作用。 CD4+ T 细胞将开发脂质体系统，将 A2AR 激动剂递送至脾脏，抑制脾脏白细胞。其次，我们将确定心脾轴通过 HMGB1/mtDNA（来自缺血心肌）引起 I/R 损伤 - RAGE/TLR9（在脾 CD4+ T 细胞上）途径我们将采用具有较短 I/R、20 分钟缺血的小鼠模型。和 60 分钟再灌注，并用来自 40 分钟缺血小鼠的缺血心脏匀浆 (IHH) 或冠状动脉灌注液 (CP) 和在 5 分钟再灌注时获得的血浆治疗小鼠 IHH、CP 或血浆中的 HMGB1 和/或 mtDNA。通过与 RAGE 或 TLR9 受体结合来激活脾 CD4+ T 细胞并加剧梗塞面积最后，我们将确定治疗阻断是否有效。血液中的HMGB1或mtDNA足以阻断心脾轴，减少心肌梗塞面积并保留心脏功能。