Integrins in the Developing Lung

发育中的肺中的整合素

基本信息

批准号：
10674710
负责人：
Erin J Plosa
金额：
$ 64.33万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-08-01 至 2027-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10674710
关键词：
3-Dimensional Adhesions Basement membrane Binding Cell Differentiation process Cell physiology Cells Cessation of life Cilia Collagen Critical Pathways Data Defect Development Developmental Biology ECM receptor Epithelial Cells Epithelium Exhibits Extracellular Matrix Extracellular Matrix Proteins Fetal Lung Functional disorder Gene Expression Genes Genetic Hemidesmosomes Histologic Human Impairment In Vitro Integrin Binding Integrin alpha3beta1 Integrin alpha6beta4 Integrins Intermediate Filaments Keratin Laminin Ligands Link LoxP-flanked allele Lung Lung diseases Minor Morphogenesis Mus Mutation Neonatal Organ Organogenesis Pathway Analysis Pathway interactions Perinatal mortality demographics Phenotype Phosphorylation Play Primary Cell Cultures Proliferating Pulmonary Emphysema Regulation Reporting Role SHH gene Signal Pathway Signal Transduction Structure Testing Tissues Tracheal Epithelium Transmission Electron Microscopy airway epithelium airway obstruction bone morphogenetic protein receptors cell behavior cilium biogenesis human disease kinetosome lung development lung health migration novel novel strategies pulmonary hypoplasia receptor receptor expression reconstitution single-cell RNA sequencing support network transcription factor

项目摘要

PROJECT SUMMARY Human and murine lung development requires the coordinated efforts of the lung epithelium with the surrounding extracellular matrix (ECM), but the ECM-directed mechanisms that govern epithelial cell behavior in the lung remain undefined. In epithelial tissues, integrins serve as receptors for the basement membrane components collagen and laminins (LMs), with LMs being the most important ECM protein for lung organogenesis. Lung epithelial cells bind to LMs through integrins α3β1, α6β1, and α6β4. Recent studies reported that mutations in these integrins cause pulmonary hypoplasia or neonatal emphysema complicated by abnormal airways, suggesting they play a major role in human developmental lung diseases. To investigate the role of LM-binding integrins, we generated lung epithelial specific integrin deletions. Deletion of both the β1 and α6 subunits resulted in marked branching defects and early death. Deletion of α3 caused only minor airway branching disruption. β4 deficient mice exhibited normal branching but, surprisingly, were also perinatal lethal. The β4 histological examination was notable for proteinaceous material filling the airways and lack of cilia, similar to α6 deficient mice, suggesting their demise resulted from airway dysfunction. Pathway analysis of α6 deficient lung sequencing data revealed disruptions in BMP signaling, a critical pathway for airway branching. BMP receptor expression was increased in α6-null epithelial cells, but BMP target gene expression remained markedly reduced, implicating α6-containing integrins in regulation of the BMP pathway in the fetal lung. Consistent with loss of cilia in β4 deficient mice, β4-null epithelial cells exhibited reduced expression of transcription factors linked to MCC terminal differentiation. As a critical component of hemidesmosomes, α6β4 controls tight adhesion to the basement membrane and connects with the intracellular keratin intermediate filaments. Keratin also forms a support network apically for cilia, suggesting that α6β4 regulates keratin organization critical for terminal differentiation of MCCs in the lung. Taken together, these findings indicate that: 1) α6β1 is the principal integrin required for airway branching likely through BMP signaling and 2) α6β4 regulates terminal differentiation of MCCs. Based on preliminary data, we propose the hypothesis that α6-containing integrins are critical integrins for fetal lung development through regulation of BMP signaling during airway branching and terminal differentiation of multi-ciliated epithelial cells. AIM 1: Determine the mechanisms whereby α6-containing integrins regulate lung branching morphogenesis. AIM 2: Define the mechanisms whereby α6-containing integrins regulate BMP signaling during fetal lung development. AIM 3: Identify the role of α6β4 integrin in airway epithelial cell differentiation.

项目概要人类和小鼠肺的发育需要肺上皮与肺组织的协调努力围绕细胞外基质 (ECM)，但控制上皮细胞行为的 ECM 导向机制在肺中的作用尚不清楚。在上皮组织中，整合素充当基底膜的受体。成分胶原蛋白和层粘连蛋白 (LM)，其中 LM 是肺最重要的 ECM 蛋白肺上皮细胞通过整合素 α3β1、α6β1 和 α6β4 与 LM 结合。报道称，这些整合素的突变会导致肺发育不全或新生儿肺气肿并发气道异常，表明它们在人类发育性肺部疾病中发挥着重要作用。为了研究 LM 结合整合素的作用，我们生成了肺上皮特异性整合素缺失。 β1 和 α6 亚基的缺失导致明显的分支缺陷和 α3 的早期死亡。仅造成轻微的气道分支破坏，β4 缺陷小鼠表现出正常的分支，但令人惊讶的是， β4 组织学检查的结果是，蛋白质物质充满了胚胎。气道和纤毛缺乏，与 α6 缺陷小鼠类似，表明它们的死亡是由于气道功能障碍所致。 α6 缺陷肺测序数据的通路分析揭示了 BMP 信号传导的破坏，这是一个关键的因素 α6 缺失上皮细胞中气道分支通路的 BMP 受体表达增加，但 BMP 受体表达增加。靶基因表达仍然显着降低，暗示含有α6的整合素参与调节胎儿肺中的 BMP 途径与 β4 缺陷小鼠的纤毛损失一致，β4 缺失上皮细胞表现出纤毛缺失。与 MCC 终末分化相关的转录因子表达减少。半桥粒中，α6β4 控制与基底膜的紧密粘附，并与细胞内角蛋白中间丝也形成纤毛顶部的支持网络。 α6β4 调节角蛋白组织，这对于肺部 MCC 的终末分化至关重要。这些发现表明：1) α6β1 是可能通过 BMP 进行气道分支所需的主要整合素 2) α6β4 调节 MCC 的终末分化。假设含 α6 的整合素是胎儿肺发育的关键整合素多纤毛气道分支和终末分化过程中BMP信号的调节上皮细胞。目标 1：确定含 α6 整合素调节肺分支的机制形态发生。目标 2：定义含 α6 整合素在胎儿期调节 BMP 信号传导的机制肺部发育。目标 3：确定 α6β4 整合素在气道上皮细胞分化中的作用。