Resident Leukocytes in Lung Ischemia-Reperfusion Injury

描述(申请人提供)：尽管在肺移植生物学方面已经有了相当大的进展，但移植后缺血再灌注损伤仍然是早期死亡的主要来源。虽然已知循环白细胞在肺IR损伤中起重要作用，但驻留肺白细胞的作用仍不清楚。因此，我们的长期目标是了解细胞因子和白细胞介导的急性肺IR损伤的机制。本课题采用小鼠原位缓冲灌流肺缺血再灌注模型，研究肺内滞留、间质白细胞和细胞因子在肺缺血再灌注损伤早期的作用。该项目将检验这一总体假设，即主要是常驻肺巨噬细胞被IR激活，产生肿瘤坏死因子-α，并为启动全面的肺IR损伤奠定基础。此外，ATL-303激活腺苷A2a受体抑制巨噬细胞活化，应可减轻大部分急性肺IR损伤。 具体目标1将确定对肺IR损伤早期、急性阶段的诱导至关重要的常驻肺白细胞(巨噬细胞、中性粒细胞、淋巴细胞)。我们推测急性肺IR损伤主要是由肺巨噬细胞引起的。 特异性目标2将确定导致急性肺IR损伤的关键早期转录事件(核因子-kappaB激活)和细胞因子/趋化因子激活(肿瘤坏死因子-α、干扰素-γ、IL-1、MIP-1α、MCP-1和RANTES)，并确定负责的白细胞。我们假设，损伤在很大程度上是由巨噬细胞产生的肿瘤坏死因子-α和肿瘤坏死因子-α通过细胞因子、趋化因子和转录因子介导的信号传导引起的。 特异性目标3将确定激活常驻白细胞上的腺苷A2a受体是否可独立于循环白细胞改善急性肺IR损伤。我们假设，主要激活肺巨噬细胞上的A2a受体将独立于循环白细胞而改善肺IR损伤。 即使在最有经验的医院，IR损伤仍然是肺移植术后早期发病率和死亡率的主要原因。拟议的研究将直接解决IR损伤的原因，并希望启动进一步的研究，重点关注旨在预防或改善急性肺IR损伤的治疗策略。

DESCRIPTION (PROVIDED BY APPLICANT): Although there has been considerable progress in lung transplant biology, post-transplant ischemia-reperfusion (IR) injury remains the major source of early mortality. Although circulating leukocytes are known to be important in lung IR injury, the role of resident lung leukocytes remains unknown. Thus our long-term goal is to understand the mechanisms of cytokine- and leukocyte-mediated acute lung IR injury. This Project focuses on the role of resident, interstitial lung leukocytes and cytokine mediators in the early phase of lung IR injury by using an in situ, buffer-perfused mouse lung IR model. This project will test the overall hypothesis that it is primarily the resident pulmonary macrophages which are activated by IR, produce TNF-alpha, and set the stage for initiation of full-blown lung IR injury. In addition, inhibition of macrophage activation by ATL- 303 activation of adenosine A2A receptors should ameliorate the majority of acute lung IR injury. Specific Aim 1 will identify the resident lung leukocytes (macrophages, neutrophils, lymphocytes) that are critical for induction of the early, acute phase of lung IR injury. We hypothesize that acute lung IR injury is primarily initiated by the pulmonary macrophages. Specific Aim 2 will determine key early transcriptional events (NF-kappaB activation) and cytokine/ chemokine activation (TNF-alpha, IFN-gamma, IL-1, MIP-1alpha, MCP-1, and RANTES) leading to acute lung IR injury, and identify the responsible leukocytes. We hypothesize that injury is largely, but not solely, initiated by macrophage-produced TNF-alpha and TNF-alpha-mediated signaling via cytokines, chemokines, and transcription factors. Specific Aim 3 will determine if activation of adenosine A2A receptors on resident leukocytes ameliorates acute lung IR injury independent of circulating leukocytes. We hypothesize that A2A receptor activation primarily on pulmonary macrophages will ameliorate lung IR injury independent of circulating leukocytes. Even in the most experienced hospitals, IR injury continues to be a major cause of morbidity and mortality early after lung transplantation. The proposed studies will directly address the causes IR injury with the hopes of initiating further studies focusing on therapeutic strategies aimed at preventing or ameliorating acute lung IR injury.