Macrophage heterogeneity in atrial remodeling

心房重构，包括扩张和纤维化，可导致血流动力学恶化和心房颤动。 其结果是，心输出量下降，心房血栓栓塞到大脑、肠道和其他器官。 虽然瓣膜手术和抗凝治疗可以减少心力衰竭和中风，但仍有 许多患者将受益于抑制心房重构及其后果的治疗。至 为了解决这一迫切的未得到满足的临床需求，我们在此建议研究巨噬细胞的作用，第四 数量最多的心肌细胞，在心房重构中。在此应用程序的前期工作中，i)我们开发了 验证了结合关键临床危险因素的新的小鼠心房重构模型，ii)我们获得了单一的- 来自心房重构小鼠左心房的细胞RNA测序(scRNA-seq)数据，iii)我们确定 心房巨噬细胞在稳态和心房重塑后的个体发育，以及iv)我们建立了 心脏手术患者左心房组织中scRNA-seq的表达 MGH。我们现在建议测试巨噬细胞是否形成了心房的阿喀琉斯跟腱，是否促进了心房重构， 纤维化和房颤。我们将探讨巨噬细胞亚群在心房重构中的作用。 和药物细胞耗尽策略。我们假设在心房重塑过程中，疾病的发生 巨噬细胞来自血液单核细胞，而本地来源的巨噬细胞具有保护作用。在这些 研究中，我们将通过超声心动图、血流动力学和超声心动图来描述左心房的结构重构 电生理检查、组织学分析和流式细胞术，然后进行实时定量聚合酶链式反应。我们的预赛 Scrna-seq数据为我们提供了大量的潜在靶点来研究纤维化相关的因果关系。 通过功能丧失和功能获得研究巨噬细胞基因在心房重构中的作用。我们将检验这一假设 骨髓源性细胞中的基因缺失，即招募的巨噬细胞亚群，通过以下方式减轻心房纤维化 与成纤维细胞的相互作用和胶原沉积减少，导致心房重构减少和减少 心房颤动的诱发性。为了达到翻译的目的，我们将研究人心房巨噬细胞的异质性。 组织经scRNA-seq.我们将重点比较人类和小鼠scRNA-seq数据集。 使用最先进的计算方法将临床前发现工作引导到 在人类疾病中很重要。我们的协作应用程序联合了一个具有以下专业知识的跨学科团队 免疫学、心血管科学和计算生物学。虽然这项新颖的研究计划雄心勃勃，但我们 相信我们的初步数据证明了可行性，并为我们提供了一个研究 具有很高临床相关性的问题。

Atrial remodeling, including dilation and fibrosis, can lead to hemodynamic deterioration and atrial fibrillation. As a consequence, cardiac output declines and atrial clots embolize to the brain, intestines and other organs. While valve surgery and anticoagulation therapy reduce heart failure and stroke, there are nevertheless numerous patients who would benefit from a therapy inhibiting atrial remodeling and its consequences. To address this urgent unmet clinical need, we here propose to investigate the role of macrophages, the fourth most numerous cardiac cell, in atrial remodeling. In preliminary work for this application, i) we developed and validated a new mouse model of atrial remodeling that combines key clinical risk factors, ii) we obtained single- cell RNA-sequencing (scRNA-seq) data from the left atria of mice with atrial remodeling, iii) we determined the ontogeny of atrial macrophages in the steady state and after atrial remodeling, and iv) we established a pipeline for scRNA-seq of human left atrial tissues from patients with atrial disease undergoing heart surgery at MGH. We now propose to test if macrophages form the atria's Achilles' heel promoting atrial remodeling, fibrosis and atrial fibrillation. We will explore the role of macrophage subsets in atrial remodeling using genetic and pharmaceutical cell depletion strategies. We hypothesize that during atrial remodeling, disease-promoting macrophages are derived from blood monocytes while locally sourced macrophages are protective. In these studies, we will profile structural remodeling of the left atrium by echocardiography, hemodynamic and electrophysiological studies, histological analysis and FACS followed by real-time qPCR. Our preliminary scRNA-seq data provide us with a wealth of potential targets to study the causal role of fibrosis-related macrophage genes in atrial remodeling by loss- and gain-of-function studies. We will test the hypothesis that gene deletion in bone marrow-derived cells, i.e. recruited macrophage subsets, attenuates atrial fibrosis by cross-talk to fibroblasts and reduced collagen deposition, leading to less atrial remodeling and reduced inducibility of atrial fibrillation. In a translational aim, we will study macrophage heterogeneity in human atrial tissues by scRNA-seq. We will focus on the comparison between human and mouse scRNA-seq data sets using state-of-the-art computational methods to steer the preclinical discovery work towards pathways that are important in human disease. Our collaborative application unites an interdisciplinary team with expertise in immunology, cardiovascular science and computational biology. While the novel research plan is ambitious, we believe that our preliminary data demonstrate feasibility and provide us with a unique opportunity to study a question with high clinical relevance.