IRE1α mediated dysregulation of the pulmonary epithelium in lung fibrosis

项目摘要/摘要 特发性肺纤维化(IPF)是一种进行性间质纤维化的疾病，可导致严重的 虚弱，最终导致呼吸衰竭和死亡。内质网中的蛋白质折叠应激 应激)触发未折叠蛋白反应(UPR)，这已被认为与IPF有关。最深刻的 UPR的保守介质是IRE1α，它是一种双功能的激酶/内切核酸酶，介导XBP1mRNA 剪接，内质网定位的mRNAs(RIDD)的降解，以及microRNA miR-17的降解。在严重情况下 内质网应激，IRE1UPR过度活跃促进细胞死亡，这种情况被称为终末期α。节俭的观点 认为终末期UPR导致持续的肺泡上皮细胞死亡，最终导致纤维化。 Feroz Papa博士(共同导师)的实验室开发并表征了激酶抑制核糖核酸酶 抑制IRE1α所有主要功能的衰减剂(KIRA)化合物。我们之前已经证明，老鼠 用KIRA化合物处理的小鼠可以预防博莱霉素诱导的纤维化。在新的初步数据中，单声道- 选择性KIRA化合物抑制miR-17降解、转化生长因子β信号转导及衰老相关基因 博莱霉素后肺上皮细胞的分泌表型(SASP)。在纤维化的小鼠肺和人IPF肺中， 这些受IRE1α调控的病理基因信号主要存在于功能失调的祖细胞中。 这些结果挑战了目前普遍认为的UPR仅通过细胞死亡导致纤维化的观点。 相反，这一提议的中心假设是，在受损的上皮细胞中，IRE1α的过度激活 前体细胞触发相互增强的纤维化通路网络，包括miR-1基因抑制。 17、衰老与转化生长因子β信号转导。特定目标1将检验IRE1α是必要的假设，并且 通过询问化学或遗传抑制对上皮祖细胞功能障碍的影响 IRE1α在博莱霉素模型和两种基于衰老的纤维化遗传模型(Sin3a基因敲除)和 ER应激(SftpcC121G)。特定目标2将检验IRE1α调节祖细胞功能障碍的假说 通过miR-17使用条件性缺失和条件性过表达小鼠。 培训计划的重点是肺再生和发育生物学的技能和概念， 肺生物学、上皮细胞功能障碍和负责任的实验室管理的体外模型。培训将会 包括授课课程、专题讨论会和国际会议。主要导师和共同导师 迪恩·谢泼德博士和费罗兹·帕帕博士都是有成就的内科科学家，有长期的 师徒关系。欧阳博士在加州大学旧金山分校观澜湾分校拥有实验室和办公空间，环境肥沃 进行协作，随时访问本研究所需的设施和设备。 总而言之，这个职业发展奖的申请合并了一位特殊的候选人，一位创新的 而驯服的研究计划，严谨的训练，以及世界级医师-科学家的支持，使之成为一名强大的 为启动对肺部疾病有很大影响的富有成效和独立的职业生涯提供跳板。

Project Summary / Abstract Idiopathic pulmonary fibrosis (IPF) is a disease of progressive interstitial fibrosis, which leads to severe debilitation and eventually respiratory failure and death. Protein folding stress in the endoplasmic reticulum (ER stress) triggers the unfolded protein response (UPR), which has been implicated in IPF. The most deeply conserved mediator of the UPR is IRE1α, a bifunctional kinase/endoribonuclease that mediates XBP1 mRNA splicing, degradation of ER-localized mRNAs (RIDD), and degradation of the microRNA miR-17. Under severe ER stress, IRE1α hyperactivity promotes cell death, a condition termed the terminal UPR. A parsimonious view holds that the terminal UPR causes ongoing alveolar epithelial cell death which leads ultimately to fibrosis. The laboratory of Dr. Feroz Papa (co-mentor) developed and characterized Kinase Inhibiting RNase Attenuator (KIRA) compounds that inhibit all the major functions of IRE1α. We previously showed that mice treated with KIRA compounds were protected from bleomycin-induced fibrosis. In new preliminary data, a mono- selective KIRA compound decreased miR-17 degradation, TGFβ signaling and the senescence-associated secretory phenotype (SASP) in the lung epithelium after bleomycin. In fibrotic mouse lungs and human IPF lungs, these IRE1α-regulated pathological gene signatures were preferentially found in dysfunctional progenitor cells. These results challenge the current paradigm that the UPR contributes to fibrosis exclusively through cell death. Instead, the central hypothesis of this proposal is that hyperactivation of IRE1α in injured epithelial progenitor cells triggers a network of mutually reinforcing fibrotic pathways, including gene repression by miR- 17, senescence, and TGFβ signaling. Specific Aim 1 will test the hypothesis that IRE1α is necessary and sufficient for epithelial progenitor cell dysfunction by interrogating the effects of chemical or genetic inhibition of IRE1α in the bleomycin model and two genetic models of fibrosis based on senescence (Sin3a knockout) and ER stress (SftpcC121G). Specific Aim 2 will test the hypothesis that IRE1α regulates progenitor cell dysfunction through miR-17 using conditional deletion and conditional overexpression mice. The training plan is focused on the skills and concepts of lung regeneration and developmental biology, in vitro models of lung biology, epithelial cell dysfunction, and responsible laboratory management. Training will include didactic courses, focused symposia, and international conferences. The primary mentor and co-mentor are Dr. Dean Sheppard and Dr. Feroz Papa, both accomplished physician-scientists with long track records of mentorship. Dr. Auyeung has laboratory and office space at the UCSF Mission Bay campus, a fertile environment for collaboration with ready access to the facilities and equipment necessary for this research. In summary this Career Development Award application merges an exceptional candidate, an innovative and tractable research plan, rigorous training, and the support of world-class physician-scientists into a powerful springboard for the launch of a productive and independent career with high impact on lung disease.