Deciphering the mechanisms of CD4 T cell activation in nonischemic heart failure

摘要 重新提交F31的目的是研究T细胞激活的机制及其后果 在致命的心力衰竭综合征(HF)中，目前是中国人死亡和住院的主要原因 美国。利用已建立的横动脉缩窄(TAC)所致心力衰竭的小鼠模型，我们和 其他研究表明T细胞在心脏重塑和功能中起着中心致病作用。然而， 心衰时T细胞活化的具体机制尚不清楚。经典的T细胞激活发生在 抗原提呈细胞，包括树突状细胞(DC)、B细胞和巨噬细胞， 通过T细胞受体(TCR)。新出现的证据表明，T细胞也可以被警报激活， 可溶炎性介质，通过TCR非经典途径。我的初步研究 在野生型和卵清蛋白(OVA)免疫的OT-II转基因小鼠中使用TAC模型，其中 经典T细胞反应仅限于卵泡蛋白，表明经典和非经典T细胞激活均可发生 并可单独导致心脏纤维化(CF)，但不足以导致心脏功能障碍。这个 触发因素(特定的心脏抗原或警报)，这些T细胞激活途径的时间和位置 而参与心力衰竭进展的APC尚不清楚。基于这些数据，我将测试 中心假设经典和非经典T细胞激活机制共同启动和 在TAC诱导的心衰进展过程中维持病理性心脏重构和心功能不全。我 我将在两个特定的目标(SA)中检验这一假设。SA1将确定经典比赛的具体地点和时间 在Nur77GFP小鼠的TAC过程中，T细胞TCR激活和APC触发这一反应，这是短暂的 表达GFP以响应TCR刺激(SA1a)。我还将确定在此期间出现的TCR克隆类型 从小鼠心脏分离单个GFP+CD4+T细胞TCR测序研究TAC诱导的心衰进展 TAC小鼠(SA1b)。在SA2中，我将进行WT和警报感觉受损的采用迁移实验 效应者将CD4+T细胞注入小鼠体内，正常保护小鼠免受心力衰竭的影响，并评估心脏重构和功能。这就做 进一步探讨ALARMIN诱导T细胞依赖的体外循环(SA2b)的机制。治疗性 还将评估TAC诱导的心脏重塑发生后耗尽CD4+T细胞的可能性 (SA2C)。在我的导师和合作者的支持下完成这些目标将导致更深层次的 了解控制T细胞免疫反应的时间和进程的新机制 心脏的病理重塑，同时支持我的训练潜力和博士候选人资格。

ABSTRACT The goal of this F31 resubmission is to investigate the mechanisms of T cell activation and the consequences in the deadly syndrome of heart failure (HF), currently the leading cause of mortality and hospitalizations in the USA. Using the well- established mouse model of HF induced by transverse aortic constriction (TAC), we and others have demonstrated a central pathogenic role for T cells in cardiac remodeling and function. However, the specific mechanisms of T cell activation in HF remain unknown. Classic T cell activation occurs upon antigen presentation by antigen presenting cells, including dendritic cells (DCs), B cells and macrophages, through the T cell receptor (TCR). Emerging evidence suggests that T cells can also be activated by alarmins, soluble inflammatory mediators, through TCR independent pathways in a “non classic" manner. My preliminary data using the TAC model in wild type and ovalbumin (OVA) immunized OT-II transgenic mice, in which classic T cell responses are limited to OVA, indicate that both classic and non-classic T cell activation occur and can separately lead to cardiac fibrosis (CF), but are not sufficient to induce cardiac dysfunction. The triggers (specific cardiac antigens or alarmins), the timing and the location of these T cell activation pathways and the APC involved during the progression of HF remain unknown. Based on these data, I will test the central hypothesis that both classic and non classic T cell activation mechanisms cooperate to initiate and sustain pathological cardiac remodeling and cardiac dysfunction during the progression of TAC induced HF. I will test this hypothesis in two specific aims (SA). SA1 will determine the specific location and timing of classic T cell TCR activation and the APCs triggering this response during TAC using Nur77GFP mice, which transiently express GFP in response to TCR stimulation (SA1a). I will also identify the TCR clonotypes that emerge during the progression of TAC induced HF by TCR sequencing of single GFP+CD4+ T cells sorted from the heart of TAC mice (SA1b). In SA2 I will perform adoptive transfer experiments of WT and alarmin sensing-impaired effector CD4+ T cells into mice normally protected from HF and evaluate cardiac remodeling and function. I will further investigate the alarmin induced mechanisms of T cell dependent CF in vitro (SA2b). The therapeutic potential of depleting CD4+ T cells after TAC-induced cardiac remodeling has occurred will also be evaluated (SA2c). Completion of these aims with the support of my mentor and collaborators will result in a deeper understanding of novel mechanisms that control the timing, and progression of the T cell immune response in pathological remodeling of the heart, while supporting my training potential and PhD candidacy.