Immune Regulatory Roles of Endothelial Cells in Neonatal Heart Regeneration

项目摘要 心力衰竭（HF）是机械应力和慢性炎症的长期影响， 在心脏组织中发生急性缺血事件之后。目前的药物只能管理 HF的症状，并且不能修复。重要的是，心血管疾病作为主要原因持续存在 世界范围内的死亡因此，阐明心肌损伤反应的机制是至关重要的， 以实现有效的HF治疗。虽然广泛的研究都集中在补充 心肌细胞，心肌细胞，已经表明，心脏中的其他细胞类型，包括常驻细胞， 免疫细胞和内皮细胞（EC）也是维持组织稳态和协调 伤害反应。因此，了解这些不同的心肌细胞类型如何控制损伤反应， 对于对抗这种致命疾病至关重要。 左前降支动脉闭塞（LAD-0）的成年小鼠心肌梗死（MI）模型显示： 心脏重塑与人类衰竭的心脏非常相似。然而，小于8天大的新生小鼠具有 一个强大的再生能力时，受到MI，并能够实现几乎完整的功能 恢复与疤痕的决议。我们初步的单细胞RNA测序（scRNA-seq）数据揭示了一个独特的 在出生后1.5天（P1.5）再生心脏中MI后出现的内皮细胞群，但在非MI心脏中未出现。 再生P8心脏此外，免疫细胞，如巨噬细胞，在心脏中扩增， 伤害反应，以促进有利于修复的环境。这种再生EC的转录组分析 群体揭示了免疫特征，表明EC可能促进促再生免疫 通过直接骨髓细胞募集的反应。本研究的目的是确定内皮细胞在心脏中的作用， 再生鉴于上述发现，我们因此假设新生儿心脏再生内皮细胞 细胞（rEC）通过扩增修复前免疫细胞组合物来促进再生。 利用小鼠遗传学和多组学，我们的目标是揭示rEC及其免疫特征在 心脏再生我们将研究rEC是否能扩增局部修复性免疫细胞，以促进哺乳动物的免疫功能。 利用体外培养实验和体内移植研究的组合进行心脏再生。 我们将进一步研究rEC的免疫特征是否促进哺乳动物心脏再生 通过利用小鼠遗传学和体内基因编辑促进MI后修复性巨噬细胞的扩增。 这些实验将为rEC如何调节再生提供新的见解，并有助于发现新的 心力衰竭免疫调节的治疗靶点。

Project Summary Heart failure (HF) is the long term effect of the mechanical stress and chronic inflammation that occurs following an acute ischemic event in cardiac tissue. Current pharmacological agents can only manage the symptoms of HF, and are not reparative. Importantly, cardiovascular disease perpetuates as the leading cause of death worldwide. Therefore, it is crucial to elucidate the mechanisms that govern cardiac injury responses in order to realize effective HF therapies. Although extensive studies have strongly focused on the replenishment of cardiac muscle cells, cardiomyocytes, it has been shown that other cell types in the heart, including resident immune cells and endothelial cells (ECs), are also essential for maintaining tissue homeostasis and orchestrating injury responses. Thus, understanding how these different cardiac cell types govern the injury response leading up to HF is crucial for combatting this deadly disease. Adult mouse myocardial infarction (MI) models of left anterior descending arterial occlusion (LAD-O) exhibit very similar cardiac remodeling to the failing human heart. However, neonatal mice less than 8 days old possess a robust regenerative capacity when subjected to MI and are able to achieve an almost complete functional recovery with scar resolution. Our preliminary single-cell RNA sequencing (scRNA-seq) data uncovered a unique endothelial cell population that emerges post-MI in regenerative postnatal day 1.5 (P1.5) hearts but not in non- regenerative P8 hearts. Moreover, immune cells such as macrophages are expanded in the heart during an injury response to promote a pro-reparative environment. Transcriptome analysis of this regenerative EC population revealed an immune signature, suggesting that ECs may facilitate a pro-regenerative immune response via direct myeloid cell recruitment. The objective of this study is to determine the role of ECs in heart regeneration. Given the above findings, we therefore hypothesize that neonatal cardiac regenerative endothelial cells (rECs) promote regeneration by expanding a pro-reparative immune cellular composition. Utilizing mouse genetics and multi-omics, we aim to uncover the role of rECs and their immune signature in cardiac regeneration. We will study whether rECs expand local reparative immune cells to promote mammalian cardiac regeneration utilizing a combination of in vitro culturing experiments and in vivo transplantation studies. We will then further investigate whether the immune signature of rECs facilitate mammalian heart regeneration by promoting the expansion of reparative macrophages after MI utilizing mouse genetics and in vivo gene editing. These experiments will provide novel insights into how rECs regulate regeneration and help uncover new therapeutic targets in immunomodulation for heart failure.