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

摘要 F31再提交的目的是研究T细胞活化的机制及其后果。 在致命的心力衰竭综合征（HF）中，HF是目前美国死亡和住院的主要原因。 USA.使用由横向主动脉缩窄（TAC）诱导的已建立的HF小鼠模型， 其他人已经证明了T细胞在心脏重塑和功能中的中心致病作用。然而，在这方面， HF中T细胞活化的具体机制仍不清楚。经典的T细胞活化发生在 通过抗原呈递细胞，包括树突细胞（DC）、B细胞和巨噬细胞进行抗原呈递， 通过T细胞受体（TCR）。新出现的证据表明，T细胞也可以被alarmin激活， 可溶性炎症介质，通过TCR非依赖性途径以“非经典”方式。我的初步 在野生型和卵清蛋白（OVA）免疫的OT-II转基因小鼠中使用TAC模型的数据，其中 经典的T细胞应答仅限于OVA，表明经典和非经典的T细胞活化均发生 并可单独导致心脏纤维化（CF），但不足以诱发心脏功能障碍。的 触发物（特异性心脏抗原或警报素），这些T细胞激活途径的时间和位置 并且在HF进展过程中涉及的APC仍然未知。根据这些数据，我将测试 经典和非经典T细胞活化机制共同启动和 在TAC诱导的HF进展期间维持病理性心脏重构和心功能障碍。我 将在两个特定目标（SA）中测试这一假设。SA 1将确定经典的具体位置和时间 在使用Nur 77 GFP小鼠的TAC期间，T细胞TCR活化和触发该应答的APC， 响应TCR刺激表达GFP（SA 1a）。我还将识别出TCR克隆型， 通过从心脏中分选的单个GFP+ CD 4 + T细胞的TCR测序，TAC诱导的HF的进展 TAC小鼠（SA 1b）。在SA 2中，我将进行WT和报警蛋白感知受损的小鼠的过继转移实验。 将效应CD 4 + T细胞植入正常保护免于HF的小鼠中，并评估心脏重塑和功能。我会 进一步研究alarmin诱导T细胞依赖性CF的体外机制（SA 2b）。治疗 还将评估TAC诱导的心脏重塑发生后耗竭CD 4 + T细胞的潜力 （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细胞免疫应答的时间和进展的新机制， 心脏的病理性重塑，同时支持我的培训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.