THE REGULATION OF NEUTROPHIL EXTRACELLULAR TRAPS (NETS) BY ADENOSINE IN MYOCARDIAL ISCHEMIA-REPERFUSION

项目概要/摘要 缺血心脏的再灌注在心肌梗死中是挽救生命的，但生理过程 再灌注引发的并发症会导致后续损伤。先天免疫系统在免疫系统中起着重要作用。 再灌注损伤中性粒细胞释放多种毒性介质及其作用的评价 细胞外陷阱（NET）在MI/R病理生理学中的重要性日益增加。腺苷是已知的减轻许多 促炎性免疫过程，而ATP从死亡和坏死细胞释放，激活免疫细胞。 ATP通过在许多细胞上表达的外核苷酸酶代谢为腺苷，包括间充质细胞 基质细胞（MSCs）。已知MSC高度表达外三磷酸核苷二磷酸水解酶-1 （NTDPase 1，CD 39）和胞外-5 '-核苷酸酶（CD 73）。嘌呤代谢的调节可能是一个强大的 MSC用于抑制其天然骨髓中的炎症以及当移植用于 治疗目的。 目前对NET产生的内源性调节知之甚少，我们假设， 腺苷可能是关键的内源性调节剂。我们的初步数据显示，MSC移植到 藻酸盐包裹的心脏可以调节对MI/R的先天性炎症反应。此外，委员会认为， 包封的MSC增加心肌腺苷水平，减少活性氧， 24小时后心脏中白细胞和中性粒细胞的数量。我们将使用人类中性粒细胞以及 从缺乏关键腺苷受体的小鼠中分离的中性粒细胞，以了解腺苷信号传导的作用 在MI/R。我们还将使用MI/R的啮齿动物模型来测试我们的新型NET体内调控策略。结果 这些研究将确定新的治疗策略，用于治疗先天性免疫MI/R损伤。 我们的目的是：1）阐明腺苷受体2A（A2 A）信号转导在调节细胞凋亡中的重要性， NET形成; 2）评估参与NET调节的细胞内信号通路; 3）测试NET形成的可行性。 MSC调节嘌呤代谢以防止MI/R中的NET。

PROJECT SUMMARY/ABSTRACT Reperfusion of the ischemic heart is lifesaving in myocardial infarction, but the physiologic processes triggered by reperfusion can cause subsequent damage. The innate immune system plays a prominent role in reperfusion injury. Neutrophils release multiple toxic mediators and the appreciation of the role of neutrophil extracellular traps (NETs) in MI/R pathophysiology is gaining importance. Adenosine is known to mitigate many pro-inflammatory immune processes while ATP released from dying and necrotic cells, activates immune cells. ATP is metabolized to adenosine by ectonucleotidases expressed on many cells including mesenchymal stromal cells (MSCs). MSCs are known to highly express ecto-nucleoside triphosphate diphosphohydrolase-1 (NTDPase1, CD39) and ecto-5’-nucleotidase (CD73). Modulation of purinergic metabolism may be a powerful mechanism used by MSCs to inhibit inflammation in their native bone marrow as well as when transplanted for therapeutic purpose. Currently little is known about endogenous regulation of NET production and we have hypothesize that adenosine may be a key endogenous regulator. Our preliminary data shows that MSC transplanted to the heart encapsulated in alginate can modulate the innate inflammatory response to MI/R. Furthermore, encapsulated MSCs increase myocardial adenosine levels, reduce reactive oxygen species, and decrease the number of leukocytes and neutrophils in the heart after 24 hours. We will use human neutrophils as well as neutrophils isolated from mice lacking key adenosine receptors to understand the role of adenosine signaling in MI/R. We will also use a rodent model of MI/R to test our novel NET-regulatory strategy in vivo. The results of these studies will identify new therapeutic strategies for treatment of innate immune MI/R injury. It is our aims to 1) delineate the importance of adenosine receptor 2A (A2A) signaling in the regulation of NET formation; 2) evaluate the intracellular signaling pathways involved in NET regulation; 3) test the feasibility of MSC modulation of purinergic metabolism to prevent NETs in MI/R.