Epithelial abnormalities in IPF: role of ER stress and GRP78/BiP

IPF 中的上皮异常：ER 应激和 GRP78/BiP 的作用

基本信息

批准号：
8577607
负责人：
Beiyun Zhou
金额：
$ 39.03万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-01 至 2018-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8577607
关键词：
Acetylcysteine Address Alveolar Antioxidants Apoptosis Binding Bone Marrow Cell Line Cells Cicatrix Data Deposition Disease Dose Endoplasmic Reticulum Environment Epithelial Epithelial Cells Epithelium Etiology Extracellular Matrix Fibroblasts Fibrosis Functional disorder Generations Goals Hamman-Rich syndrome Homeostasis In Vitro Injury Interstitial Lung Diseases Knock-out Knockout Mice Lead Link Lung Lung diseases Mediating Mediator of activation protein Membrane Mesenchymal Modeling Molecular Molecular Chaperones Mus Mutation Myofibroblast Oxidative Stress Pathogenesis Pathway interactions Phenotype Play Predisposition Process Proteins Pulmonary Fibrosis Pulmonary Surfactant-Associated Protein C Reactive Oxygen Species Reporting Respiratory physiology Role Signal Transduction Tissues Wound Healing age related alveolar epithelium biological adaptation to stress cell injury clinically relevant effective therapy endoplasmic reticulum stress fibrogenesis glucose-regulated proteins in vivo inhibitor/antagonist injured insight monolayer mutant new therapeutic target novel overexpression pneumocyte prevent protein degradation protein folding protein misfolding public health relevance response sensor src-Family Kinases surfactant treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP) is a devastating interstitial lung disease of unknown etiology, characterized by (myo)fibroblast activation/proliferation, extracellular matrix (ECM) deposition and progressive lung destruction. A central role for alveolar epithelium in IPF/UIP pathogenesis has recently been postulated. In this paradigm, injured alveolar epithelial cells (AEC) actively participate in fibrogenesis by releasing fibroproliferative mediators that promote proliferation an differentiation of fibroblasts that in turn induce AEC apoptosis and/or giving rise directly to fibroblasts through epithelial-mesenchymal transition (EMT). However, mechanisms underlying AEC injury/activation and downstream molecular pathways linking epithelial abnormalities to fibrosis remain unclear. Association between endoplasmic reticulum (ER) stress and both sporadic and familial pulmonary fibrosis associated with surfactant protein (SP) mutations has been reported. We recently found that ER stress triggers protective signaling known as the unfolded protein response (UPR) and induces both apoptosis and EMT in AEC in vitro via activation of the non-receptor membrane-associated tyrosine kinase Src, supporting a causal role for ER stress in the dysfunctional AEC phenotype in pulmonary fibrosis. Preliminary data suggest that reactive oxygen species (ROS) and b-catenin activation/interaction with the co-activator CBP are involved in Src-dependent signaling. The ER chaperone glucose-regulated protein 78 (GRP78) is a master regulator of ER homeostasis and thus represents an ideal target with which to modulate ER stress responses in alveolar epithelium. The overall goals of this proposal are to investigate mechanisms underlying ER stress-induced epithelial abnormalities implicated in the pathogenesis of fibrosis by modulating GRP78 utilizing mice with lung epithelial cell-specific deletion of Grp78. We hypothesize that (1) loss of Grp78 induces and/or exacerbates experimental fibrosis in vivo; (2) GRP78 insufficiency-induced epithelial injury contributes to fibrosis via direct effects on the epithelium (e.g., apoptosis/EMT) and/or abnormal epithelial-fibroblast crosstalk; and, (3) effects of GRP78 insufficiency on EMT/fibrosis are mediated via Src and/or ROS-dependent ¿-catenin/CBP signaling. We will use AEC-specific Grp78 knockout mice, in conjunction with clinically relevant mutant SP-C¿exon4, our well- established primary AEC in vitro monolayer model, and ICG-001, a novel inhibitor of ¿-catenin/CBP interaction, to address the following Specific Aims: 1. Evaluate effects of ER stress mediated by loss of Grp78 on pulmonary fibrosis in inducible AEC-specific Grp78 knockout mice; 2. Investigate the role of ER stress in AEC abnormalities (apoptosis vs EMT vs aberrant epithelial-fibroblast crosstalk) implicated in fibrosis in inducible AEC-specific Grp78 knockout mice; and 3. Determine mechanisms underlying ER stress-induced AEC injury/fibrosis. These studies will provide insights into mechanisms underlying the pathogenesis of IPF and facilitate identification of novel therapeutic targets for this incurable disease.

描述（由申请人提供）：特发性肺纤维化/普通间质性肺炎（IPF/UIP）是一种病因不明的破坏性间质性肺疾病，其特征是（肌）成纤维细胞活化/增殖、细胞外基质（ECM）沉积和进行性肺破坏。最近提出了肺泡上皮在 IPF/UIP 发病机制中的核心作用，在此范例中，损伤的肺泡上皮细胞。 (AEC) 通过释放促进成纤维细胞增殖和分化的纤维增殖介质积极参与纤维形成，进而诱导 AEC 凋亡和/或通过上皮间质转化 (EMT) 直接产生成纤维细胞。将上皮异常与纤维化联系起来的下游分子途径仍不清楚内质网（ER）应激与散发性和家族性肺病之间的关系。我们最近发现，内质网应激会触发称为未折叠蛋白反应 (UPR) 的保护性信号传导，并通过非受体膜的激活在体外诱导 AEC 细胞凋亡和 EMT。相关的酪氨酸激酶 Src，支持 ER 应激在肺纤维化功能失调的 AEC 表型中的因果作用。初步数据表明，活性氧 (ROS) 和 β-连环蛋白的激活/相互作用。共激活剂 CBP 参与 Src 依赖性信号传导。 ER 伴侣葡萄糖调节蛋白 78 (GRP78) 是 ER 稳态的主要调节因子，因此是调节肺泡上皮内质网应激反应的理想靶标。该提案的目的是通过利用具有肺上皮细胞的小鼠调节 GRP78 来研究与纤维化发病机制有关的 ER 应激诱导上皮异常的机制Grp78 的细胞特异性缺失。我们认为（1）Grp78 的缺失会诱导和/或加剧体内实验性纤维化；（2）GRP78 不足诱导的上皮损伤通过对上皮的直接影响（例如细胞凋亡/）导致纤维化。 EMT）和/或异常上皮-成纤维细胞串扰；以及（3）GRP78 不足对 EMT/纤维化的影响；通过 Src 和/或 ROS 依赖性介导 ¿ -catenin/CBP 信号传导我们将使用 AEC 特异性 Grp78 敲除小鼠，以及临床相关的突变体 SP-C¿ exon4（我们完善的初级 AEC 体外单层模型）和 ICG-001（一种新型 ¿ 抑制剂） -catenin/CBP 相互作用，以解决以下具体目标： 1. 评估 Grp78 缺失介导的 ER 应激对诱导型 AEC 特异性 Grp78 敲除小鼠的肺纤维化的影响； 2. 研究 ER 应激在 AEC 异常（细胞凋亡）中的作用； vs EMT vs 异常上皮-成纤维细胞串扰）涉及诱导型 AEC 特异性 Grp78 的纤维化3. 确定 ER 应激引起的 AEC 损伤/纤维化的机制。这些研究将深入了解 IPF 的发病机制，并有助于识别这种不治之症的新治疗靶点。