Understanding how alveolar epithelial cell stress drives aberrant repair in interstitial lung disease

了解肺泡上皮细胞应激如何驱动间质性肺疾病的异常修复

• 批准号: 10200141
• 负责人: Jeremy Binder Katzen
• 金额: $ 16.79万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10200141
• 关键词: Address; Adult; Air Sacs; Alveolar; Alveolitis; Apoptosis; Apoptotic; Automobile Driving; Autophagocytosis; Bioinformatics; Cell Culture Techniques; Cell Differentiation process; Cell Line; Cell Proliferation; Cells; Cellular Stress; Cellular biology; Child; Chronic Disease; Coupled; Coupling; Data; Defect; Development; Disease; Disease model; Epithelial; Epithelial Cells; Fibrosis; Functional disorder; Gene Mutation; Generations; Genes; Genetic; Human; In Vitro; Inflammation; Injury; Interstitial Lung Diseases; Knock-in; Knock-in Mouse; Link; Lung; Lung diseases; Mesenchymal; Mesenchyme; Modeling; Molecular; Mus; Mutate; Mutation; Organoids; Pathogenesis; Pathologic; Pathway interactions; Patients; Pharmacology; Phenotype; Play; Pre-Clinical Model; Proliferating; Protein Isoforms; Proteins; Publishing; Pulmonary Fibrosis; Pulmonary Pathology; Pulmonary Surfactant-Associated Protein C; Research; Respiratory Failure; Role; Signal Pathway; Signal Transduction; System; Techniques; Therapeutic; Training; alveolar epithelium; base; biological adaptation to stress; citrate carrier; endoplasmic reticulum stress; human disease; in vivo; in vivo Model; injury and repair; interstitial; lung injury; lung repair; mouse model; multimodality; mutant; novel; patient subsets; pre-clinical; progenitor; programs; repaired; stem cell function; stem cells; surfactant; theories; therapeutic evaluation; therapeutic target; trafficking; transcriptome sequencing

PROJECT SUMMARY Interstitial lung diseases (ILDs) are a class of pulmonary diseases pathologically defined by interstitial fibrosis and inflammation. Owing to our limited understanding of the upstream initiators of pathogenesis, ILDs have poor prognoses and limited therapeutics. Mutations in the Alveolar Epithelial Type 2 Cell (AEC2) restricted Surfactant Protein C (SP-C) gene (SFTPC) in a subset of ILD patients supports a growing hypothesis that AEC2 dysfunction is a driver of disease. When we model these disease-related SFTPC mutations in vitro they segregate into two major classes based upon how the mutated SP-C isoform stresses cellular pathways that manage abnormal proteins: mutations that inhibit macroautophagy and mutations that cause endoplasmic reticulum (ER) stress. However, how these AEC2 stress phenotypes, which have also been identified in ILD patients without SFTPC mutations, relate to ILD development remains poorly understood. To understand this relationship, we have generated two unique Sftpc mutation knock-in mouse models, one expressing an SP-C isoform that induces AEC2 macroautophagy dysfunction (SP-CI73T) and the other inducing ER stress (SP-CC121G). Each of these mutations when expressed in the adult mouse lung results in spontaneous alveolitis and lung injury followed by aberrant repair with resultant fibrotic ILD. These models thus provide proof of concept that AEC2 stress is capable of driving spontaneous lung pathology and are robust preclinical platforms. These models also support a second emerging theory of ILD pathogenesis: that in ILD AEC2s, which must act as critical facultative progenitor cells after lung injury by both proliferating and differentiating to repair damaged epithelium, develop dysfunction in their progenitor cell capacity. We discovered that while similar lung pathology develops in each of our Sftpc models, there are divergent AEC2 proliferation phenotypes following lung injury: SP-CI73T AEC2s become hyperpoliferative and SP-CC121G AEC2s become apoptotic and hypoproliferative. Thus, our models support the hypothesis that abnormal AEC2 progenitor cell function plays a central role in ILD development, and also create a platform to develop a mechanistic understanding of how discrete AEC2 stress signatures result in distinct defects in progenitor cell capacity. This proposal has three interrelated aims that seek to understand the molecular and cellular mechanisms that relate AEC2 cell stress, dysfunctional progenitor cell capacity, and ILD. Aim 1 uses bioinformatics and in vivo linage-tracing to characterize the AEC2 stress signaling and progenitor function pathways involved in each model. Aim 2 provides a mechanistic link between cell stress signaling and progenitor cell dysfunction through ex vivo organoid culture and in vivo modeling. In Aim 3 we will generate the first ILD patient-derived iPSC culture model of an ER stress associated SFTPC mutation as a humanized platform to study the pathways identified in Aims 1 and 2. This proposal will also provided the trainee with the diverse and comprehensive training necessary to develop a multimodal independent research program on the role of the epithelium in ILD.

项目摘要 间质性肺疾病（Interstitial lung diseases，ILD）是一类以肺间质纤维化为病理特征的肺部疾病 和炎症。由于我们对发病机制的上游启动子的了解有限， 药物和有限的治疗。肺泡上皮2型细胞（AEC 2）中的突变限制表面活性剂 ILD患者亚群中的蛋白C（SP-C）基因（SFTPC）支持越来越多的假设，即AEC 2 功能障碍是疾病的驱动因素。当我们在体外模拟这些疾病相关的SFTPC突变时， 根据突变的SP-C亚型如何应激细胞途径，将其分为两大类， 管理异常蛋白质：抑制大自噬的突变和引起内质网的突变 内质网应激。然而，这些AEC 2应激表型（也已在ILD中被鉴定）如何 对于无SFTPC突变的患者，与ILD发生的关系仍知之甚少。 为了理解这种关系，我们已经产生了两种独特的Sftpc突变敲入小鼠模型， 表达诱导AEC 2大自噬功能障碍的SP-C同种型（SP-CI 73 T），和表达诱导AEC 2大自噬功能障碍的SP-C同种型（SP-CI 73 T）， ER应力（SP-CC 121 G）。当在成年小鼠肺中表达时，这些突变中的每一种都会导致自发性肺内炎。 肺泡炎和肺损伤，随后异常修复，导致纤维化ILD。这些模型证明了 概念上，AEC 2应激能够驱动自发性肺病理学，并且是稳健的临床前 平台这些模型也支持ILD发病机制的第二个新兴理论：在ILD AEC 2中， 必须作为关键的兼性祖细胞后，肺损伤的增殖和分化修复 受损的上皮细胞，在它们的祖细胞能力中发展出功能障碍。我们发现，虽然类似的肺 在我们的每个Sftpc模型中，病理学发展，在以下情况下存在不同的AEC 2增殖表型： 肺损伤：SP-CI 73 T AEC 2变得过度增殖，SP-CC 121 G AEC 2变得凋亡， 低增殖。因此，我们的模型支持这一假设，即异常的AEC 2祖细胞功能发挥了重要作用。 在ILD发展中的核心作用，并创建一个平台，以建立一个机制，了解如何 离散的AEC 2应激信号导致祖细胞能力的明显缺陷。 该提案有三个相互关联的目标，旨在了解分子和细胞机制， 与AEC 2细胞应激、祖细胞功能障碍和ILD相关。AIM 1使用生物信息学和体内 谱系追踪以表征参与每一个细胞的AEC 2应激信号传导和祖细胞功能途径。 模型目的2提供了细胞应激信号传导和祖细胞功能障碍之间的机制联系， 离体类器官培养和体内建模。在目标3中，我们将产生第一个ILD患者来源的iPSC ER应激相关SFTPC突变的培养模型作为研究途径的人源化平台 在目标1和2中确定。这一建议也将为学员提供多样化和全面的 必要的培训，以开发一个关于上皮在ILD中的作用的多模式独立研究计划。