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: 10434900
• 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/10434900
• 关键词: Address; Adult; Air Sacs; Alveolar; Alveolitis; Alveolus; 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; Prognosis; 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; fibrotic interstitial lung disease; fibrotic lung disease; 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.

项目总结 间质性肺疾病(ILDS)是一类以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者的了解有限，ILDS的发病情况很差 预后和有限的治疗。肺泡上皮2型细胞限制性表面活性物质的突变 ILD患者亚群中的蛋白C(SP-C)基因(SFTPC)支持一个日益增长的假说，即AEC2 功能障碍是疾病的驱动力。当我们在体外模拟这些与疾病相关的SFTPC突变时，它们 根据突变的SP-C亚型对细胞通路的压力将其分为两大类 处理异常蛋白质：抑制巨噬的突变和引起内质的突变 内质网(ER)应激。然而，这些AEC2是如何应对ILD中也发现的表型的 没有SFTPC突变的患者与ILD的发展相关仍然知之甚少。 为了理解这种关系，我们产生了两个独特的Sftpc突变敲入小鼠模型，一个 表达一种诱导AEC2巨噬功能障碍的SP-C亚型(SP-CI73T) 内质网应激(SP-CC121G)。当这些突变在成年小鼠肺中表达时，每一个都会导致自发的 肺泡炎和肺损伤后的异常修复与由此产生的纤维性ILD。因此，这些模型提供了证据 AEC2应激能够导致自发性肺病理并且是强大的临床前的概念 站台。这些模型还支持ILD发病机制的第二种新兴理论：在ILD AEC2中， 肺损伤后必须通过增殖和分化修复作为关键的兼性祖细胞 受损的上皮细胞，其祖细胞能力会出现功能障碍。我们发现，虽然相似的肺 在我们的每一种Sftpc模型中，都有不同的AEC2增殖表型 肺损伤：SP-CI73T AEC2细胞肥大，SP-CC121G AEC2细胞凋亡 低增殖性。因此，我们的模型支持这样的假设，即异常的AEC2祖细胞功能在 在ILD开发中发挥核心作用，并创建一个平台，以发展对如何 离散的AEC2应激信号会导致祖细胞能力的明显缺陷。 这一提议有三个相互关联的目标，试图了解分子和细胞机制 AEC2细胞应激、祖细胞功能障碍和ILD之间的关系。目标1使用生物信息学和活体实验 AEC2逆境信号和前体功能通路的连锁示踪 模特。AIM 2通过以下途径在细胞应激信号和祖细胞功能障碍之间提供了机制联系 体外有机物培养和体内建模。在目标3中，我们将生成第一个ILD患者来源的IPSC 内质网应激相关SFTPC突变的培养模型及其人源化平台的研究 目标1和目标2中确定。这项建议还将为受训人员提供多样化和全面的 进行必要的培训，以制定关于上皮细胞在ILD中的作用的多模式独立研究计划。