Mechanisms of Pulmonary Fibrosis in Hermansky-Pudlak Syndrome

Hermansky-Pudlak 综合征肺纤维化的机制

• 批准号: 10165784
• 负责人: Lisa R. Young
• 金额: $ 44万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10165784
• 关键词: Adaptor Signaling Protein; Adult; Affect; Aging; Binding; Biogenesis; Blood Platelets; CCL2 gene; CRISPR/Cas technology; Cell Adhesion Molecules; Cell Culture Techniques; Cell membrane; Cell physiology; Cells; Coculture Techniques; Complex; Data; Defect; Development; Disease; Distal; Early Endosome; Endosomes; Epithelial; Epithelial Cells; Family; Fibroblasts; Fibrosis; Functional disorder; Funding; Genes; Genetic; Goals; Hereditary Disease; Hermanski-Pudlak Syndrome; Human; Interstitial Lung Diseases; Intervention; Knowledge; Link; Lung; Lysosomes; Mediating; Mediator of activation protein; Modeling; Molecular; Mus; Mutation; Oculocutaneous Albinism; Organelles; PAR-1 Receptor; Pathogenesis; Pathway interactions; Pharmacology; Phenotype; Predisposition; Prevention strategy; Production; Proteins; Publishing; Pulmonary Fibrosis; Receptor Cell; Receptor Signaling; Recycling; Research; Shortness of Breath; Signal Pathway; Signal Transduction; System; Testing; Therapeutic; Transforming Growth Factor beta; Transgenic Organisms; Transmembrane Transport; alveolar epithelium; base; cell injury; gene product; human disease; insight; macrophage; mouse model; novel therapeutics; prevent; protein transport; proteostasis; receptor; respiratory; trafficking; young adult

Hermansky-Pudlak Syndrome (HPS) is a family of autosomal recessive disorders characterized by oculocutaneous albinism and highly penetrant pulmonary fibrosis. Despite knowledge of the underlying genetic defects, there are currently no therapeutic or preventative approaches for HPS pulmonary fibrosis. Our published data demonstrate that alveolar epithelial cells (AECs) are the primary drivers of fibrotic susceptibility in HPS; however, the underlying mechanisms by which AECs dysfunction results in fibrosis remain undefined and represent an important knowledge gap in the field of fibrosis research. Studies during the current funding period have enabled us to define key phenotypes of HPS AECs with connections to fibrotic susceptibility in HPS mice. Specifically, we showed excess production of MCP-1 and increased Nox4-mediated ROS production by AECs contributes to fibrosis. A major goal of this proposal is to define how these pro-fibrotic AEC phenotypes relate to the underlying molecular defect in HPS. In search of a mechanism that underlies the observed pro-fibrotic phenotype of AECs in HPS, we recently identified increased TGFβ pathway activation in unstimulated HPS AECs. Activated type I and type II TGFβ receptors are constitutively recycled into endosomes, and early endosomes have been recognized as a vital signaling organelle for TGFβ signaling. Based on our preliminary data, we propose to investigate how compromised endosomal trafficking resulting from the genetic defect in HPS2 (loss of AP-3) alters proteostasis and dysregulates TGFβ signaling and AEC function. Our hypothesis is that defective endosomal trafficking in HPS alters TGFβ receptor signaling, thereby resulting in persistent and increased Smad and Erk1/2 signaling. These altered signaling pathways result in increased expression of MCP-1, Nox4, and other mediators by AECs that create a pro-fibrotic microenvironment in the distal lung. To test this hypothesis, we propose the following specific aims using cell culture models and a disease relevant HPS mouse model that develops spontaneous and progressive fibrosis with aging: 1) to determine how loss of AP-3 results in increased TGFβ signaling and expression of pro-fibrotic mediators by AECs, 2) to determine how AECs promote fibroblast activation in HPS, and 3) to investigate mechanisms of pulmonary fibrosis in HPS that develops with aging. Defining the mechanisms of AEC dysfunction in HPS could provide new insights into pathogenesis of HPS and other forms of pulmonary fibrosis, thus facilitating development of new therapeutic and preventative strategies for this fatal disorder.

Hermansky-Pudlak综合征(HPS)是一种常染色体隐性遗传病家族，其特征是 眼皮肤白化病和高度穿透性肺纤维化。尽管知道潜在的基因 对于HPS的缺陷，目前还没有治疗或预防HPS肺纤维化的方法。我们的 已发表的数据表明，肺泡上皮细胞(AECs)是纤维化易感性的主要驱动因素 然而，在HPS中，AECs功能障碍导致纤维化的潜在机制仍不清楚。 并代表着纤维化研究领域的一个重要的知识缺口。在当前资助期间进行的研究 使我们能够确定HPS AECs的关键表型与肝纤维化易感性有关 HPS小鼠。具体地说，我们发现MCP-1的过度产生和NOX4介导的ROS增加 血管内皮细胞的产生会导致纤维化。这项提案的一个主要目标是定义这些促肝纤维化的 AEC表型与HPS潜在的分子缺陷有关。在寻找一种建立在 HPS中AEC的促纤维化表型，我们最近发现转化生长因子β途径的激活增加 在未受刺激的HPS AEC中。激活的I型和II型转化生长因子β受体被结构性地循环到 内体和早期内体被认为是转化生长因子β信号转导的重要信号细胞器。 基于我们的初步数据，我们建议调查如何导致受损的内体贩运 由于HPS2的遗传缺陷(AP-3缺失)改变蛋白平衡，并失调转化生长因子β信号和血管内皮细胞 功能。我们的假设是，有缺陷的HPS内体运输改变了转化生长因子β受体信号，从而 导致持续的和增加的Smad和ERK1/2信号。这些改变的信号通路导致 血管内皮细胞增加MCP-1、NOX4和其他介质的表达，从而产生促纤维化 远端肺的微环境。为了验证这一假设，我们提出了使用CELL的以下具体目标 自发性和进行性纤维化的培养模型和疾病相关的HPS小鼠模型 随着年龄的增长：1)确定AP-3的缺失如何导致转化生长因子β信号和促纤维化表达的增加 AECs的介体，2)确定AECs如何促进HPS中成纤维细胞的激活，以及3)研究 HPS中随年龄增长而发展的肺纤维化机制。定义AEC的机制 HPS的功能障碍可以为HPS和其他形式的肺纤维化的发病机制提供新的见解， 从而促进了针对这种致命疾病的新的治疗和预防策略的开发。