Regulation of T cell immune response in Heart Failure with Preserved Ejection Fraction

R 01应用的目的是研究T细胞导致心力衰竭的机制 (HF)射血分数保留（HFpEF），影响大约50%的HF患者。特别是 改善射血分数降低的HF（HFrEF）患者生存率和结局的治疗 在HFpEF患者中未提供临床获益，这些患者通常存在多种合并症， 包括肥胖和高血压。HFpEF患者的相关流行病学研究表明， 炎症对HFpEF的贡献。然而，潜在的免疫机制仍然主要是 未开发的在临床前模型中复制的人类HFpEF的独特心肌标志， 心脏代谢性HFpEF是未折叠蛋白反应（UPR）的下调，这导致 细胞无法科普内质网（ER）应激，UPR的中心功能，因此 损害心肌细胞松弛。我们的初步数据使用心脏代谢的实验模型， HFpEF揭示了心脏T细胞浸润与舒张功能障碍并存的新发现， 心肌细胞肥大，T细胞缺陷小鼠（Tcra-/-）不发生舒张功能障碍， 心肌细胞肥大在相同的条件下。我们的数据还显示，编码特定 ER应激反应因子如X-box蛋白1（XBP 1 s）和激活转录因子6（ATF 6）， 在从心脏代谢性HFpEF小鼠分离的CD 4 + T细胞中显著下调，而在T细胞中没有 从HFrEF小鼠身上。XBP 1 s的T细胞下调与增强的T细胞效应因子 功能和抗肿瘤活性。这项建议将测试的中心假设，失调的T细胞- 内源性ER应激反应促进心脏代谢性HFpEF中的有害炎症。在AIM 1中，我们将 使用单细胞抗体和RNA测序（CITE-Seq）来揭示T细胞转录谱 在WT小鼠心脏代谢HFpEF的整个发展过程中，研究 T细胞应答、所涉及的优势T细胞亚群及其拯救保护性表型的能力 在Tcra-/-受体小鼠中观察到。在目的2中，我们将确定在免疫抑制过程中T细胞UPR的表达。 心脏代谢性HFpEF的进展，并利用功能获得和丧失方法来定义 T细胞UPR在心脏代谢性HFpEF中受损并影响T细胞前体的机制 炎症效应子功能。在目标3中，我们将研究T细胞内在ER应激的功能作用， HFpEF进展过程中心肌细胞肥大和功能的反应以及T细胞衍生的 通过UPR受损改变影响心肌细胞肥大和功能的因素，使用小鼠 T细胞中选择性缺乏UPR效应子，以及获得功能的方法。 所提出的目标的成功实现有望确定新的T细胞内在机制 在HFpEF中促进有害的免疫反应，为开发新的 免疫调节策略来对抗这种致命的综合征。

The goal of this R01 application is to investigate the mechanisms by which T cells contribute to heart failure (HF) with preserved ejection fraction (HFpEF), affecting roughly 50% of the HF patients. Notably, the treatments that improve survival and outcomes in patients with HF with reduced ejection fraction (HFrEF) have not provided clinical benefit in HFpEF patients, who often present with multiple comorbidities that include obesity and hypertension. Correlative epidemiological studies in HFpEF patients, suggest a potential contribution of inflammation to HFpEF. However the underlying immune mechanisms remain largely unexplored. A unique myocardial hallmark of human HFpEF replicated in a pre-clinical model of cardiometabolic HFpEF is the downregulation of the unfolded protein response (UPR), which results in the cellular inability to cope with endoplasmic reticulum (ER) stress, the central function of the UPR, thus impairing cardiomyocyte relaxation. Our preliminary data using an experimental model of cardiometabolic HFpEF reveal the novel finding that cardiac T cell infiltration co-exists with diastolic dysfunction and cardiomyocyte hypertrophy, and that T cell deficient mice (Tcra-/-) do not develop diastolic dysfunction or cardiomyocyte hypertrophy under the same conditions. Our data also reveal that genes encoding specific ER stress response factors such as X-box protein 1 (XBP1s) and activating transcription factor 6 (ATF6), are remarkably downregulated in CD4+ T cells isolated from mice with cardiometabolic HFpEF, and not in T cells from mice with HFrEF. T cell downregulation of XBP1s has been implicated in enhanced T cell effector function and anti-tumor activity. This proposal will test the central hypothesis that dysregulation of T cell- intrinsic ER stress responses promotes detrimental inflammation in cardiometabolic HFpEF. In Aim1, we will use single cell antibody and RNA sequencing (CITE-Seq) to uncover the T cell transcriptional profiles throughout the development of cardiometabolic HFpEF in WT mice, investigate the antigen dependence of the T cell response, the dominant T cell subsets involved, and their ability to rescue the protective phenotype observed in Tcra-/- recipient mice. In Aim 2, we will determine the expression of the T cell UPR during the progression of cardiometabolic HFpEF and utilize gain-and loss-of- function approaches to define the mechanisms by which the T cell UPR is compromised in cardiometabolic HFpEF and impacts T cell pro- inflammatory effector function. In Aim 3, we will investigate the functional role of the T cell-intrinsic ER stress response in cardiomyocyte hypertrophy and function during the progression of HFpEF and the T cell derived factors altered by the compromised UPR that impact cardiomyocyte hypertrophy and function, using mice selectively lacking UPR effectors in T cells, and gain of function approaches,. Successful accomplishment of the Aims proposed is expected to identify novel T cell intrinsic mechanisms that foster detrimental immune responses in HFpEF, paving the way for the development of new immunomodulatory strategies to confront this deadly syndrome.