Defining the lineage, mechanisms of maintenance, and function of a new injury-resistant airway epithelial structure: the hillock

定义新的抗损伤气道上皮结构的谱系、维持机制和功能：小丘

• 批准号: 10364896
• 负责人: JAYARAJ RAJAGOPAL
• 金额: $ 46.74万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10364896
• 关键词: Ablation; Age; Airway Disease; Apical; Applications Grants; Area; Attention; Basal Cell; Behavior; Bladder; Cartilage; Cells; Chronic Obstructive Pulmonary Disease; Coupled; Cytokeratin; Diffuse; Diphtheria Toxin; Disease; Epidermis; Epithelial; Epithelial Cells; Genetic; Homeostasis; Human; Image; Injury; Label; Liver; Maintenance; Mediating; Metaplasia; Modeling; Molecular; Morphology; Mus; Names; Natural regeneration; Play; Polyploid Cells; Polyploidy; Population; Pseudostratified Epithelium; Regulation; Reporting; Resistance; Role; Shapes; Signal Transduction; Skin; Smoking; Smooth Muscle; Squamous Metaplasia; Stereotyping; Stratification; Stratified Epithelium; Structure; System; Trachea; Tretinoin; Vitamin A; Vitamin A Deficiency; airway epithelium; airway regeneration; airway repair; cell motility; chemical genetics; design; epithelial repair; in vivo; injured airway; injury and repair; migration; mouse model; novel; repaired; severe injury; stem cell migration; stem cells; two-photon

We recently identified a novel airway epithelial structure, the hillock, in the murine trachea and we present evidence that similar structures occur in the human airway epithelium. Airway epithelial hillocks are stratified epithelial structures with multiple layers of cells that are distinct from the classic pseudostratified epithelium that lines most of the airway lumen. They possess novel polyploid luminal epithelial cells, but completely lack ciliated cells. We now show that these stratified hillock epithelial structures resist multiple forms of airway injury. We hypothesize that the stratified structure of hillock cells results in a protective barrier, in analogy to the protective function of the stratified epidermal cells that lie atop epidermal basal cells. Furthermore, we show that hillocks contain a unique population of basal stem cells marked by Cytokeratin 13 (KRT13). These basal cells are characterized by a very high baseline rate of turnover and are capable of rapidly migrating over denuded airway epithelium. We hypothesize that the diffuse distribution of injury-resistant airway hillocks facilitates disseminated migration of stem cells that have resisted severe injury. We show preliminary evidence that hillock basal stem cells, which are the first highly defined subset of airway basal cells in the murine trachea, are plastic and can produce normal pseudostratified epithelium after damage to recreate a normal epithelium. Finally, we show that murine hillocks increase in size and number with age. Interestingly, both smoking-induced squamous metaplasia and vitamin A-deficiency induced squamous metaplasia have both been associated with stratified KRT13+ epithelium suggesting they may originate from hillock-like cells. In this grant application, we first propose to define the lineage and plasticity of hillocks during homeostasis and after injury using 2 distinct genetic driver lines that are designed to specifically label hillocks and even more specifically hillock basal cells. We will also determine the functional significance of hillocks during epithelial homeostasis and after injury repair using diphtheria toxin- mediated ablation in combination with models of airway injury, with special attention focused on assessing the role of hillock polyploid cells. Using a combination of an explant model of murine tracheal regeneration, 2-photon live imaging, and the chemical and genetic modulation of a human hillock culture system, we will dissect the molecular mechanisms of hillock differentiation and hillock-mediated injury repair with a focus on the specific role of retinoic acid signaling and the association of hillocks to squamous metaplasia.

我们最近在小鼠气管中发现了一种新的气道上皮结构，即小丘，我们 目前的证据表明，人类气道上皮细胞中也存在类似的结构。气道上皮 小丘是分层上皮结构，具有多层细胞，与细胞不同 典型的假复层上皮排列在大部分气道管腔内。他们拥有新颖的 多倍体管腔上皮细胞，但完全缺乏纤毛细胞。我们现在证明这些 分层小丘上皮结构可抵抗多种形式的气道损伤。我们假设 小丘细胞的分层结构形成保护屏障，类似于保护功能 位于表皮基底细胞顶部的复层表皮细胞。此外，我们表明 小丘含有独特的基底干细胞群，以细胞角蛋白 13 (KRT13) 为标志。 这些基底细胞的特点是基线周转率非常高，并且能够 在裸露的气道上皮上快速迁移。我们假设弥散分布 抗损伤气道小丘促进已抵抗损伤的干细胞的播散性迁移 重伤。我们展示了初步证据表明小丘基底干细胞是第一个 小鼠气管中高度明确的气道基底细胞子集，是塑料的，可以产生 正常假复层上皮损伤后重建正常上皮。最后，我们展示 小鼠小丘的大小和数量随着年龄的增长而增加。有趣的是，两者都是由吸烟引起的 鳞状上皮化生和维生素A缺乏引起的鳞状上皮化生均已被 与复层 KRT13+ 上皮相关，表明它们可能起源于小丘样细胞。 在本次拨款申请中，我们首先提出定义小丘的谱系和可塑性 使用 2 个不同的基因驱动系来实现稳态和损伤后，这些基因驱动系专门设计用于 标记小丘，更具体地标记小丘基底细胞。我们还将确定功能 小丘在上皮稳态和使用白喉毒素损伤后修复过程中的意义 介导消融与气道损伤模型相结合，特别关注 评估小丘多倍体细胞的作用。使用小鼠外植体模型的组合 气管再生、2 光子实时成像以及化学和遗传调节 人类小丘培养体系，剖析小丘分化的分子机制 和小丘介导的损伤修复，重点关注视黄酸信号传导和 小丘与鳞状化生的关联。