Probing the mechanisms of epithelial barrier restoration in the distal lung

探讨远端肺上皮屏障恢复机制

• 批准号: 10677534
• 负责人: Joshua Daniel Guild
• 金额: $ 3.28万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-30 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10677534
• 关键词: Ablation; Acute; Acute Respiratory Distress Syndrome; Alveolar; Alveolus; Behavior; Biological Models; Biology; Blood capillaries; Cell Death; Cell Therapy; Cells; Chronic; Chronic Obstructive Pulmonary Disease; Data; Diphtheria Toxin; Disease; Distal; EGF gene; Epidermal Growth Factor Receptor; Epithelial; Event; Failure; Fellowship; Fibroblasts; Foundations; Future; Gases; Impairment; In Situ Hybridization; Injury; Lead; Ligands; Lung; Lung Capacity; Maps; Matrix Metalloproteinases; Measures; Mediating; Minor; Modeling; Molecular; Morbidity - disease rate; Mus; Natural regeneration; Paracrine Communication; Pathway interactions; Pharmacology; Physicians; Physiological; Population; Positioning Attribute; Process; Proliferating; Proteins; Pulmonary alveolar structure; Regenerative Medicine; Regulation; Research; Respiratory Disease; Respiratory Failure; Role; Scientist; Signal Transduction; Surface; System; Testing; Therapeutic; Thinness; Training; WNT Signaling Pathway; Work; alveolar epithelium; career; cell regeneration; daughter cell; epithelium regeneration; heparin-binding EGF-like growth factor; idiopathic pulmonary fibrosis; in vivo; lung regeneration; lung repair; monolayer; mortality; mouse genetics; mouse model; prevent; programs; regeneration potential; repaired; response; restoration; self-renewal; single-cell RNA sequencing; stem cell biology; stem cell population; stem cell proliferation; stem cells; surfactant; transdifferentiation; wound healing

PROJECT SUMMARY Respiratory diseases like the Acute Respiratory Distress Syndrome, Idiopathic Pulmonary Fibrosis and Chronic Obstructive Pulmonary Disease produce significant morbidity and mortality worldwide. While each of these diseases are distinct, they all have in common a failure to maintain or repair lung alveoli. Thin, delicate alveolar type 1 (AT1) cells encompass greater than 95 percent of the alveolar gas exchange surface, interspersed with cuboidal, surfactant-secreting alveolar type 2 (AT2) cells in a monolayer epithelium. A minor subset of AT2 cells serve as the principal stem cells that renew alveoli throughout the lifetime. They function to regenerate the epithelium after injury, and there is some evidence to suggest that their disfunction underlies chronic forms of respiratory disease. Establishing a deep understanding of the biology of AT2 stem cells may lead to new pharmacological and cell-based therapies to treat these diseases. Despite recent, significant advances in lung alveolar stem cell biology, the physiological behavior of AT2 stem cells and the molecular mechanisms that regulate this behavior have proven to be challenging to define. We developed a mouse genetic system to study dynamic activation of AT2 stem cells in vivo that employs targeted ablation of AT1 cells using Diphtheria toxin. As expected, we found that AT2 cell self-duplication was rapidly induced upon AT1 cell ablation, however, this was preceded by immediate and widespread AT2-to-AT1 transdifferentiation. Our results reveal a previously unappreciated role for a (non-stem) AT2 cell population in rapidly regenerating the alveolar barrier. We hypothesize that alveolar repair involves a two-step mechanism in which direct transdifferentiation of AT2 cells into AT1 cells initially restores barrier integrity and is followed by self-duplication of AT2 stem cells. The proposed project aims to further probe the mechanisms and physiological importance of this ultra-rapid restoration of the alveolar gas exchange and barrier surface. Our findings will help to establish a foundational model of epithelial regeneration in lung alveoli, and will inform practical strategies for manipulating AT2 stem cells in therapeutic applications.

项目概要 呼吸系统疾病，如急性呼吸窘迫综合征、特发性肺纤维化和慢性肺纤维化 阻塞性肺疾病在全世界范围内产生显着的发病率和死亡率。虽然这些中的每一个 疾病各不相同，但它们的共同点都是无法维持或修复肺泡。肺泡薄而细腻 1 型 (AT1) 细胞覆盖了 95% 以上的肺泡气体交换表面，散布着 单层上皮中的立方形、分泌表面活性剂的肺泡 2 型 (AT2) 细胞。 AT2 细胞的一小部分 作为一生中更新肺泡的主要干细胞。它们的作用是再生 损伤后的上皮细胞，有一些证据表明它们的功能障碍是慢性形式的基础 呼吸道疾病。深入了解 AT2 干细胞的生物学特性可能会带来新的发现 治疗这些疾病的药物和细胞疗法。尽管最近在肺方面取得了重大进展 肺泡干细胞生物学、AT2干细胞的生理行为及其分子机制 事实证明，规范这种行为是很难定义的。我们开发了小鼠遗传系统来研究 使用白喉毒素靶向消融 AT1 细胞，动态激活体内 AT2 干细胞。 正如预期的那样，我们发现 AT1 细胞消融后，AT2 细胞自我复制迅速被诱导，然而，这 在此之前发生了立即且广泛的 AT2 至 AT1 转分化。我们的结果揭示了之前 （非干）AT2 细胞群在肺泡屏障快速再生中的作用未被认识到。我们 假设肺泡修复涉及两步机制，其中 AT2 细胞直接转分化 进入 AT1 细胞首先恢复屏障完整性，然后是 AT2 干细胞的自我复制。拟议的 该项目旨在进一步探讨这种超快速恢复的机制和生理重要性 肺泡气体交换和屏障表面。我们的研究结果将有助于建立上皮细胞的基础模型 肺泡再生，并将为在治疗中操纵 AT2 干细胞的实用策略提供信息 应用程序。