Regulation of epithelial, pro-apoptotic Endoplasmic Reticulum (ER) stress in Idiopathic Pulmonary Fibrosis (IPF).

特发性肺纤维化 (IPF) 中上皮、促凋亡内质网 (ER) 应激的调节。

• 批准号: 280798910
• 负责人: Dr. Martina Korfei
• 金额: --
• 依托单位: Klinische Forschergruppe "Lungenfibrose"
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/280798910?language=en
• 关键词: Regulation; epithelial; pro; apoptotic; Endoplasmic

Idiopathic Pulmonary Fibrosis (IPF) is a rare and lethal disease, for which no curative therapy exists to date. Endoplasmic Reticulum (ER) stress, caused by the accumulation of unfolded or misfolded proteins in the ER, is a prominent finding in injured, apoptotic type-II alveolar epithelial cells (AECII) of patients with IPF. ER stress is signalled through the unfolded protein response (UPR) pathways PERK, ATF6, and IRE1alpha. If not resolved, the UPR may induce a variety of ER stress-mediated apoptosis pathways, amongst others via induction of the pro-apoptotic transcription factor CHOP, or through those activated by phosphorylated IRE1alpha-oligomers (p-IRE1a), involving 1) the degradation of microRNAs controlling the levels of caspase family cell death substrates and other pro-apoptotic factors and 2) the activation of the Apoptosis Signal-regulating Kinase-1 (ASK1), which causes downstream activation of stress kinases c-Jun-N-terminal kinases (JNK1/2) and p38 MAPK that promote apoptosis.We hypothesize that ER stress-induced apoptosis, largely driven by CHOP, IRE1alpha and ASK1, is the major reason for death of IPF-AECII, and that this process represents a common pathomechanistic principle of sporadic and familial IPF, including gene mutations affecting telomere maintenance. We also hypothesize that IPF reflects an aberrant reparative response to repetitive alveolar epithelial injury in a (genetically) susceptible individual, and that second hits such as oxidative stress, noxious fumes, or respiratory infections are required for a full-blown activation of a pro-apoptotic ER stress-response and high level AECII apoptosis, and consequent development of lung fibrosis. Based on these hypotheses, we will address the following questions:1) Does AECII-specific conditional overexpression of Chop in transgenic mice predispose to development of pulmonary fibrosis in response to second hits (such as herpesvirus-infection and ROS exposure) or ageing?2) Does ER stress-induced AECII apoptosis involving CHOP and/or the p-IRE1a/ASK1-signalling pathway play a role in familial IPF caused by SFTPA2 mutations or gene mutations in the Telomerase-complex?3) Are adaptive, pro-survival ER stress signalling pathways activated in Clara cells of patients with SFTPA2 mutations, thereby providing one possible explanation for the concomitant development of adenocarcinoma in these families? 4) Can ER stress-mediated apoptosis induced by mutant SP-A2, SP-C, or telomere-related proteins be prevented in ASK1 or CHOP deficient alveolar epithelial cells?5) Does ASK1 offer as novel therapeutic target for IPF? We aim to evaluate therapeutic blockade of ER stress-signalling on development of lung fibrosis in vivo by using Ask1(-/-) knockout mice or the small-molecule Ask1 inhibitor selonsertib in mouse models of lung fibrosis (bleomycin, amiodarone), as well as assessing the effects of ASK1 inhibition in precision cut lung slices from IPF-patients cultured ex vivo.

特发性肺纤维化（IPF）是一种罕见的致命性疾病，迄今为止还没有治愈性治疗方法。内质网（ER）应激由ER中未折叠或错误折叠的蛋白质积累引起，是IPF患者受损、凋亡的II型肺泡上皮细胞（AECII）中的一个突出发现。ER应激通过未折叠蛋白反应（UPR）途径PERK，ATF 6和IRE 1 α发出信号。如果不解决，UPR可能诱导多种ER应激介导的凋亡途径，其中包括通过诱导促凋亡转录因子CHOP，或通过磷酸化IRE 1 α-寡聚体（p-IRE 1a）激活的途径，涉及1）控制半胱天冬酶家族细胞死亡底物和其它促凋亡因子水平的microRNA的降解和2）凋亡信号调节激酶-1（ASK 1），其引起下游的应激激酶c-Jun-N-末端激酶（JNK 1/2）和促进凋亡的p38 MAPK的激活。我们假设ER应激诱导的凋亡，主要由CHOP、IRE 1 α和ASK 1驱动，是IPF-AECII死亡的主要原因，并且该过程代表散发性和家族性IPF的共同病理机制原理，包括影响端粒维持的基因突变。我们还假设，IPF反映了（遗传）易感个体对重复性肺泡上皮损伤的异常修复反应，并且第二次打击如氧化应激、有毒烟雾或呼吸道感染是促凋亡ER应激反应和高水平AECII凋亡的全面激活以及随后肺纤维化发展所需的。基于这些假设，我们将解决以下问题：1）在转基因小鼠中，AECII特异性条件性过表达Chop是否会导致肺纤维化的发展，以响应第二次打击（如疱疹病毒感染和ROS暴露）或衰老？2)ER应激诱导的涉及CHOP和/或p-IRE 1a/ASK 1信号通路的AECII细胞凋亡是否在由SFTPA 2突变或端粒酶复合物基因突变引起的家族性IPF中发挥作用？3)适应性，促生存ER应激信号通路在SFTPA 2突变患者的Clara细胞中激活，从而为这些家族中腺癌的伴随发展提供了一种可能的解释吗？4)在ASK 1或CHOP缺陷的肺泡上皮细胞中，由突变的SP-A2、SP-C或端粒相关蛋白诱导的ER应激介导的凋亡能否被阻止？5)ASK 1是否可作为IPF的新治疗靶点？我们的目的是通过在肺纤维化小鼠模型（博莱霉素、胺碘酮）中使用Ask 1（-/-）敲除小鼠或小分子Ask 1抑制剂selonsertib，评估ER应激信号传导对体内肺纤维化发展的治疗阻断，以及评估ASK 1抑制对离体培养的IPF患者精密切割肺切片的影响。