The Biology of the ABCA3 Lipid Transporter in Health and Disease

ABCA3 脂质转运蛋白在健康和疾病中的生物学

• 批准号: 9476314
• 负责人: Surafel Mulugeta
• 金额: $ 47.03万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9476314
• 关键词: ABCA3 gene; Acute; Address; Adult; Affect; Aging; Alveolar; Anabolism; Apoptosis; Autophagocytosis; Biogenesis; Biology; Bleomycin; Carrier Proteins; Cell physiology; Cells; Cellular biology; Characteristics; Child; Chronic; Clinical; Cytoprotection; Data; Defect; Development; Disease; Environmental Risk Factor; Event; Exhibits; Exposure to; Functional disorder; Future; Gene Mutation; Gene Proteins; Gene-Modified; Genes; Growth; Hand; Health; Homeostasis; Human; Impairment; In Vitro; Infant; Inflammation; Inflammatory; Inherited; Injury; Interstitial Lung Diseases; Knock-in Mouse; Knowledge; Link; Lipids; Lung; Lung diseases; Lysosomes; Membrane; Modeling; Molecular; Mus; Mutation; Organelles; Oxidative Stress; Pathogenesis; Pathology; Pathway interactions; Patients; Peptide Signal Sequences; Phenotype; Phospholipids; Play; Predisposition; Protein Isoforms; Proteins; Pulmonary Fibrosis; Pulmonary Surfactant-Associated Protein C; Pump; Quality Control; Reporting; Role; Severities; Signal Transduction; Stress; Structure of parenchyma of lung; System; Testing; Transgenic Organisms; Treatment Efficacy; Validation; Variant; Work; age related; alveolar epithelium; alveolar lamellar body; alveolar type II cell; cytotoxicity; defined contribution; disease phenotype; gene interaction; in vivo; influenzavirus; insight; lung injury; misfolded protein; mouse model; mutant; novel; programs; public health relevance; response; surfactant; surfactant deficiency in infants; targeted treatment; trafficking

 DESCRIPTION (provided by applicant): ABCA3 functions as a lipid and phospholipid transporter and is critical for the biogenesis of lamellar bodies. Following our discovery of ABCA3 in alveolar type II (AT2) cells, its importance to lung health and disease has been highlighted by an abundance of compelling reports linking mutations in ABCA3 to various lung disorders, including fatal surfactant deficiency in newborns and chronic interstitial lung disease (ILD) in older children and adults. Building upon our prior work characterizing the basic cell biology of ABCA3, this project will use both integrative and reductionist approaches to define mechanisms and pathways underlying the cellular and organotypic consequences for the lung from the expression by AT2 cells of two distinct classes of mutant isoforms of ABCA3 proteins associated with inherited lung disorders in humans. We have identified several ABCA3 mutations that in vitro exhibit either functional (transporter) or trafficking defects with the later inducing ER stress and cytotoxicity. Furthermore, we have developed a novel transgenic knock-in (KI) mouse model expressing the most common clinical variant of ABCA3 (ABCA3E292V) that develops age dependent parenchymal lung remodeling. Our preliminary data demonstrate that this functional ABCA3 mutant disrupts cellular macroautophagy, producing cytotoxicity by lysosome-dependent and ER stress-independent pathways. Our working model proposes that ILD-associated ABCA3 mutations elicits a class-specific, distinct set of altered AT2 cell responses which then drives abnormal lung injury/remodeling. This project contains three thematically interrelated specific aims that address emerging themes critical to lung cell biology: protein quality control, organelle homeostasis, and cytoprotection. Specific Aim 1 will characterize the mechanisms underlying AT2 cell dysfunction from expression of the transport-deficient ABCA3E292V mutant in vivo. Specific Aim 2 will study the vulnerability of the ABCA3E292V lung to exogenous "2nd hits", and determine the role of concomitant ER stress in promoting and enhancing abnormal lung remodeling. Specific Aim 3 will utilize a second novel KI mouse model of ILD we recently developed bearing the most common ILD-associated mutation of the surfactant protein C (SP-C) gene, SP-CI73T, which we have recently shown to also profoundly disrupt cellular quality control including autophagy. Using this novel bi-genic model, we will then assess the consequences of SP-CI73T co-expression in modulating ABCA3E292V mutation associated pathology. Results from the proposed studies utilizing rare gene mutations in AT2 cells as models will not only enhance our knowledge of the molecular mechanisms underlying the pathophysiology of familial ILD, but also more broadly promote a better understanding of the significance of AT2 cell dysfunction-induced aberrant lung remodeling and provide strategies for future development of targeted therapies for sporadic lung fibrosis.

 描述（由申请人提供）：ABCA3 充当脂质和磷脂转运蛋白，对于层状体的生物发生至关重要。继我们在 II 型肺泡 (AT2) 细胞中发现 ABCA3 后，大量令人信服的报告强调了 ABCA3 对肺部健康和疾病的重要性，这些报告将 ABCA3 突变与各种肺部疾病联系起来，包括新生儿致命的表面活性剂缺乏和年龄较大儿童和成人的慢性间质性肺疾病 (ILD)。基于我们之前描述 ABCA3 基本细胞生物学的工作，该项目将使用综合和还原论方法来定义 AT2 细胞表达与人类遗传性肺病相关的两类不同类别的 ABCA3 蛋白突变同工型对肺产生细胞和器官型影响的机制和途径。我们已经鉴定了几种 ABCA3 突变，这些突变在体外表现出功能（转运蛋白）或运输缺陷，并随后诱导 ER 应激和细胞毒性。此外，我们开发了一种新型转基因敲入（KI）小鼠模型，表达最常见的ABCA3临床变体（ABCA3E292V），可产生年龄依赖性肺实质重塑。我们的初步数据表明，这种功能性 ABCA3 突变体会​​破坏细胞巨自噬，通过溶酶体依赖性和内质网应激独立途径产生细胞毒性。我们的工作模型提出，ILD 相关的 ABCA3 突变会引发一组特定类别的、独特的 AT2 细胞反应改变，然后导致异常的肺损伤/重塑。该项目包含三个主题相互关联的具体目标，解决对肺细胞生物学至关重要的新兴主题： 蛋白质质量控​​制、细胞器稳态和细胞保护。具体目标 1 将通过体内转运缺陷 ABCA3E292V 突变体的表达来表征 AT2 细胞功能障碍的机制。具体目标 2 将研究 ABCA3E292V 肺对外源性“第二次打击”的脆弱性，并确定伴随的 ER 应激在促进和增强异常肺重塑中的作用。 Specific Aim 3 将利用我们最近开发的第二种新型 KI 小鼠 ILD 模型，该模型具有最常见的 ILD 相关表面活性蛋白 C (SP-C) 基因 SP-CI73T 突变，我们最近证明该模型也会严重破坏包括自噬在内的细胞质量控制。使用这种新颖的双基因模型，我们将评估 SP-CI73T 共表达在调节 ABCA3E292V 突变相关病理学中的后果。利用AT2细胞中罕见基因突变作为模型的研究结果不仅将增强我们对家族性ILD病理生理学分子机制的了解，而且更广泛地促进更好地理解AT2细胞功能障碍诱导的异常肺重塑的重要性，并为未来开发散发性肺纤维化的靶向治疗提供策略。