Biosynthesis and Trafficking of Surfactant Protein C In Health and Disease

表面活性剂蛋白 C 在健康和疾病中的生物合成和运输

• 批准号: 8559147
• 负责人: MICHAEL FRANCIS BEERS
• 金额: $ 39.09万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-09 至 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8559147
• 关键词: Abnormal Epithelial Cell; Address; Adult; Affect; Alveolar; Anabolism; Apoptosis; Autophagocytosis; Binding; Binding Proteins; Bioenergetics; Biological Models; Cell membrane; Cell model; Cell physiology; Cells; Cellular biology; Cessation of life; Child; Cytoprotection; Data; Development; Disease; Distal; Epithelial; Epithelial Cells; Evaluation; Fibrosis; Functional disorder; Funding; Generations; Genes; Goals; Golgi Apparatus; Health; Homeostasis; Homologous Gene; Human; Impairment; In Vitro; Indium; Interstitial Lung Diseases; Laboratories; Ligands; Lung; Lung diseases; Mediating; Metabolism; Mitochondria; Modeling; Molecular; Monoubiquitination; Mutation; N-terminal; Organelles; Pathogenesis; Pathway interactions; Patients; Peptides; Phenotype; Phospholipids; Play; Process; Protein Isoforms; Proteins; Publishing; Pulmonary Fibrosis; Pulmonary Surfactant-Associated Protein C; Quality Control; Reporting; Respiratory Failure; Role; Signal Transduction; Stress; Structure; Surface; adapter protein; alveolar lamellar body; cytotoxicity; design; gain of function; in vitro Model; in vivo; mouse model; mutant; new therapeutic target; novel; programs; protein protein interaction; protein transport; prototype; public health relevance; recombinase; response; surfactant; trafficking; ubiquitin-protein ligase; uptake

DESCRIPTION (provided by applicant): Surfactant protein C (SP-C), a lung-specific hydrophobic peptide that enhances the biophysical activity of surfactant phospholipid, is synthesized as a 21 kD propeptide (proSP-C21) and post-translationally processed to yield a 3.7 kD surface active alveolar form. The importance of SP-C to lung health and disease has been underscored by observations that heterozygous expression of mutations in the SP-C gene (SFTPC) in humans is associated with interstitial lung disease (ILD). Recent studies from our laboratory have: (i) identified a novel PPDY motif in the proSP-C NH2 terminus and its ligand the E3 ligase Nedd4-2 as crucial elements in the targeting of proSP-C to the distal secretory pathway; (ii) functionally characterized the consequences of improper folding of the proSP-C COOH terminus for epithelial cell dysfunction seen with aggregation prone SFTPC mutations ("BRICHOS" domain) found in patients with accompanying ILD; (iii) uncovered a second class of phenotypically distinct ILD-associated SFTPC mutations ("Non-BRICHOS") that, while not ER retained, are instead mistrafficked to non-native organelles. Our published and new preliminary data also indicate that non-BRICHOS SP-C mutants disrupt both endosomal/ lysosomal function as well as macroautophagy producing cytotoxicity by ER stress independent pathways. This project seeks to build upon our long-standing discovery program studying cellular and molecular mechanisms underlying the biosynthetic metabolism of SP-C by further focusing on 3 emerging themes critical to lung cell biology: protein trafficking, organelle homeostasis, and cytoprotection. Specific Aim 1 will focus on defining the role of 4 key factors, the SP-C NH2 PPDY motif, Nedd4-2 WW domains, proSP-C monoubiquitination, and the adapter protein Golgi-associated, ?-adaptin homologues, Arf-binding protein 3 (GGA3) in anterograde trafficking of proSP-C. In addition, the consequences of proximal retention of proSP-C initiated by disruption of this targeting machinery will be studied using both well-characterized in vitro model systems and a new generation inducible, Cre-recombinase-driven mouse model of Nedd4-2 deficiency to evaluate quality control responses in vivo. In Specific Aim 2, mechanisms underlying AT2 cell dysfunction and cytotoxicity resulting from expression of mistrafficked non-BRICHOS SP-C mutant isoforms will be evaluated and compared with responses to aggregation prone COOH folding mutants. Results from the proposed studies will enhance our understanding of the molecular mechanisms underlying not only the pathophysiology of AT2 cell dysfunction that accompanies fibrotic lung remodeling in ILD but will provide a framework and model systems for "personalized" manipulation of proteostasis and cellular signaling for other disorders associated with parenchymal lung disease and epithelial dysfunction.

描述（由申请人提供）：表面活性剂蛋白C（SP-C）是一种肺特异性疏水肽，增强表面活性剂磷脂的生物物理活性，被合成为21 kD丙肽（Prosp-C21）（Prosp-C21）和后经盆后处理，以产生3.7 kD的表面表面活性肺泡形式。 SP-C对肺部健康和疾病的重要性突显了人们认为，人类SP-C基因（SFTPC）突变的杂合表达与间质肺疾病（ILD）有关。我们实验室的最新研究已有：（i）确定了PROSP-C NH2末端及其配体E3连接酶NEDD4-2的新型PPDY基序是将Prosp-C靶向远端分泌途径的关键要素； （ii）在功能上表征了Prosp-C COOH末端不当折叠对上皮细胞功能障碍的不当折叠的后果，该功能障碍在伴有ILD的患者中发现了容易发生的SFTPC突变（“ Brichos”结构域）； （iii）发现了第二类表型不同的ILD相关的SFTPC突变（“非砖”），虽然未保留，但对非本地细胞器的造成了误入率。我们已发表的新初步数据还表明，非砖头SP-C突变体破坏了内体/溶酶体功能，以及通过ER应力不足途径产生细胞毒性的大噬菌学。该项目旨在基于我们长期的发现计划，研究SP-C的生物合成代谢的基础的细胞和分子机制，通过进一步关注3个对肺部细胞生物学至关重要的新出现的主题：蛋白质运输，细胞器稳态和细胞保护作用。具体目标1将重点放在定义4个关键因素的作用上，SP-C NH2 PPDY基序，NEDD4-2 WW结构域，Prosp-C单次泛素化和适配器蛋白Golgi相关， - ADAPTIN同源物，ARF结合蛋白3（GGA3）在Prosprade of Prosp-c的术中。此外，将使用特征良好的体外模型系统和NEDD4-2缺陷的NEDD4-2缺陷的新一代诱导，Cre-crecibinase驱动的小鼠模型来研究通过这种靶向机械的破坏来启动ProSP-C的近端保留率的后果。在特定的目标2中，将评估AT2细胞功能障碍和细胞毒性的机制，这是由于表达失去的非砖头SP-C突变体同工型的表达而产生的，并将其与对聚集的Prone Prone COOH折叠突变体的反应进行比较。拟议的研究的结果将增强我们对ILD中纤维化肺重塑的AT2细胞功能障碍的病理生理的理解，不仅是ILD中伴有纤维化肺重塑的原因，而且还将为与其他疾病的蛋白质之间的“个性化”操纵和模型系统提供与其他疾病的疾病和疾病相关的疾病。