Role for Wnt/beta-catenin signaling in alveolar repair and fibrosis

项目摘要：肺纤维化是一种毁灭性的疾病，死亡率超过 在许多恶性肿瘤中。纤维化在很大程度上是由炎症驱动的模型尚未证明 转化为皮质类固醇的有效治疗。因此，新的分子洞察力可以帮助我们理解 肺纤维化是必要的。Wnt/b-catenin信号转导是细胞所需的主要途径 维持成人组织动态平衡的分化决定，最近被牵连到 纤维化症。由于组织纤维化被认为需要上皮细胞的破坏和成纤维细胞的激活， 我们假设Wnt/b-catenin信号通过靶向增殖来驱动纤维化表型。 肺上皮细胞和成纤维细胞的存活和分化。在这项提案中，我们将建立 Wnt/b-catenin信号在博莱霉素肺纤维化小鼠模型中的因果作用 这表现为减弱(LRP5-/-)或增强(AXIN2-/-)b-连环蛋白信号(目标1)。在受伤期间 博莱霉素模型的时相，我们将确定Wnt/b-catenin信号的激活是否 肺泡2型(AT2)上皮细胞存活及其肺损伤后修复能力所必需的 (目标2)。在博莱霉素模型的纤维化阶段，我们将确定是否激活 在成纤维细胞中观察到的Wnt/b-catenin信号通路促进其增殖和迁移活性。 (目标3)。我们假设有限的Wnt/b-catenin信号激活促进肺泡上皮细胞 存活和分化，揭示了在肺泡早期阶段的重要保护作用 受伤后再进行修复。然而，Wnt/b-catenin信号在成纤维细胞中的持续激活，最终 通过促进它们的增殖和迁移来驱动纤维化的表型。这项研究的发现 该提案旨在证明Wnt/b-catenin信号与肺组织之间的第一个因果联系 纤维化症。通过分析Wnt/b-catenin信号在肺泡上皮和成纤维细胞中的作用 组件，我们将提供对纤维化肺部疾病的诱因的迫切需要的洞察。

Project Summary: Pulmonary fibrosis is a devastating disease with mortality rates that exceed those of many malignancies. Models that fibrosis is largely driven by inflammation have not proven to translate into effective therapy with corticosteroids. Thus, new molecular insights into the mechanism of pulmonary fibrosis are needed. Wnt/b-catenin signaling is a major pathway required for cell differentiation decisions that maintain adult tissue homeostasis, and has recently been implicated in fibrosis. Since tissue fibrosis is thought to require both epithelial destruction and fibroblast activation, we hypothesize that Wnt/b-catenin signaling drives the fibrogenic phenotype by targeting proliferation, survival and differentiation in both lung epithelial cells and fibroblasts. In this proposal, we will establish a causal role for Wnt/b-catenin signaling in the bleomycin model for lung fibrosis, using mouse models that manifest attenuated (LRP5-/-) or enhanced (AXIN2-/-) b-catenin signaling (Aim 1). During the injury phase of the bleomycin model, we will determine whether activation of Wnt/b-catenin signaling is required for the survival of alveolar type 2 (AT2) epithelial cells and their ability to repair after lung injury (Aim 2). During the fibrogenic phase of the bleomycin model, we will determine whether the activation of Wnt/b-catenin signaling observed in fibroblasts promotes their proliferation and migratory activities. (Aim 3). We hypothesize that limited Wnt/b-catenin signaling activation promotes alveolar epithelial cell survival and differentiation, revealing an important protective role during the early stages of alveolar repair after injury. Sustained activation of Wnt/b-catenin signaling in fibroblasts, however, ultimately drives the fibrogenic phenotype by promoting their proliferation and migration. The findings of this proposal aim to demonstrate the first causal link between Wnt/b-catenin signaling and pulmonary fibrosis. By parsing the effects of Wnt/b-catenin signaling in both alveolar epithelial and fibroblast components, we will provide much needed insight into the instigating causes of fibrotic lung diseases.