T Cell mediated immune responses as a regulator of heart failure

描述（由申请人提供）：心力衰竭（HF）是一种进行性综合征，影响全球近2000万人，通常由心脏对病理性应激的重塑引起。新出现的证据将全身性炎症与左心室（LV）功能障碍和HF联系起来，但观察到的全身性炎症的机制在很大程度上尚未探索。我们使用胸主动脉缩窄（TAC）（一种明确的HF模型）的初步数据表明，T细胞被募集到心脏，心脏血管内皮被局部激活，作为LV功能障碍。有趣的是，我们发现，在体外生理流动条件下，来自经历HF的小鼠的T细胞与活化的小鼠心脏内皮细胞的相互作用显著高于来自对照小鼠的T细胞。值得注意的是，在我们的初步研究中，T细胞缺陷型小鼠（TCR γ-）的存活率增加，左心室功能得到保护，纤维化程度降低。根据这些数据，在本提案中，我们将测试 T细胞介导的免疫应答影响压力超负荷诱导的HF中的心脏重构的中心假设。我们提出了3个具体的目标来验证这一假设，其中我们将获得有关HF过程中调节小鼠和人心脏中T细胞募集机制的新信息，涉及的T细胞亚群，以及它们在调节HF心脏重塑机制中的影响。在目的1中，我们将使用视频显微镜来研究在TAC诱导的HF进展期间调节小鼠T细胞与心脏内皮细胞之间的相互作用的粘附机制，确定来自HF小鼠的T细胞是否利用选择素和/或整合素/IG超家族途径来介导体外生理流动条件下的滚动、停滞和跨内皮迁移。还将通过流式细胞术表征来自患有HF的小鼠的T细胞中粘附分子和趋化因子受体的表达和功能。目的2研究TAC诱导的T细胞介导的免疫应答，明确T细胞亚群在HF进展中的作用，以及它们在体外心肌细胞和心脏成纤维细胞功能中的作用。将进行TAC研究 在WT和TCR γ-小鼠中，不同的T细胞亚群将过继转移到接受TAC的TCR γ-受体小鼠中。将通过超声心动图和血液动力学研究确定LV功能，通过匹可斯红染色确定纤维化，并将使用流式细胞术、qPCR、蛋白质印迹和免疫组织化学方法确定T细胞亚群及其细胞因子对心肌细胞和成纤维细胞功能的影响。在目标3中将使用类似的方法，通过探索调节HF中人类T细胞募集的机制，将我们在目标1和2中的发现转化为人类生物学。这些目标的完成将使我们更深入地了解如何最好地调节T细胞介导的炎症，以改善衰竭心脏的结构、功能和分子缺陷，并将根据我们对控制心脏病理性重塑中T细胞免疫应答的时间、类型和进展的新机制的基本理解，确定治疗HF的替代治疗方法。

DESCRIPTION (provided by applicant): Heart failure (HF) is a progressive syndrome affecting nearly 20 million people worldwide and is generally caused by remodeling of the heart in response to pathological stress. Emerging evidence associates systemic inflammation with left ventricular (LV) dysfunction and HF, but the mechanisms for the observed systemic inflammation are largely unexplored. Our preliminary data using Thoracic aortic constriction (TAC), a well-defined model of HF, indicates that T cells are recruited to the heart and the heart vascular endothelium is activated locally as LV function worsens. Interestingly, we found that T cells from mice undergoing HF interact with activated mouse heart endothelial cells in significant higher numbers than T cells from control mice under physiological flow conditions in vitro. Remarkably, T cell deficient mice (TCR�-) showed increased survival, preserved LV function, and decreased fibrosis in our pilot studies. Based on these data, in this proposal we will test the central hypothesis that T cell mediated immune responses influence cardiac remodeling in pressure overload induced HF. We propose 3 specific aims to test this hypothesis, in which we will obtain novel information about the mechanisms regulating mouse and human T cell recruitment in the heart during the course of HF, the T cell subsets involved, and their influence in the mechanisms regulating cardiac remodeling in HF. In Aim 1 we will use videomicroscopy to study the adhesion mechanisms regulating interactions between mouse T cells and heart endothelial cells during the progression of HF induced by TAC, determining if T cells from mice with HF utilize selectin and/or integrin/Ig superfamily pathways, to mediate rolling, arrest and transendothelial migration under physiological flow conditions in vitro. The expression and functionality of adhesion molecules and chemokine receptors in T cells from mice with HF will also be characterized by flow cytometry. Aim 2 will characterize the T cell mediated immune response induced by TAC, define the role of T cell subsets during the progression of HF, and their role in cardiomyocyte and cardiac fibroblast function in vitro. TAC studies will be performed in WT and TCR�- mice and different T cell subsets will be adoptively transferred into TCR�- recipient mice undergoing TAC. LV function will be determined by echocardiography and hemodynamic studies, fibrosis by picosirious red staining, and flow cytometry, qPCR, western blot and Immunohistochemistry approaches will be used to determine the effect of T cell subsets and their cytokines in cardiac myocyte and fibroblast function. Similar approaches will be used in Aim 3 to translate our findings in Aims 1 and 2 to human biology by exploring the mechanisms regulating human T cell recruitment in HF. Completion of these aims will result in a deeper understanding of how best to regulate T cell mediated inflammation to improve the structural, functional and molecular deficits of the failing heart, and will identify alternative therapeutic approaches to treat HF based on our basic understanding of novel mechanisms that control the timing, type and progression of the T cell immune response in pathological remodeling of the heart.