Epithelial Beta-catenin Signaling Improves Chronic Renal Injury

上皮β-连环蛋白信号传导改善慢性肾损伤

• 批准号: 10612208
• 负责人: Leslie S Gewin
• 金额: --
• 依托单位: ST. LOUIS VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2023-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10612208
• 关键词: Epithelial; Beta; catenin; Signaling; Improves

Chronic kidney disease (CKD) is a growing public health problem that affects more than 10% of Veterans, increases morbidity and mortality, and imposes a huge economic burden. Persistent renal tubular injury is an important component of tubulointerstitial fibrosis (TIF), the common feature of progressive CKD of any etiology. Growth factors such as transforming growth factor- (TGF-) and Wnt/-catenin are important determinants of how tubular epithelia respond to injury. Various inhibitors of the Wnt/-catenin pathway have had mixed effects on chronic renal injury. We used a genetic approach to augment -catenin signaling in the proximal tubule, and this resulted in marked improvement in CKD progression after renal injury. Wnt/-catenin signaling mediates very different actions in injury versus homeostasis. Our preliminary data suggest that -catenin binding to the transcription factor FoxO may be an important mediator of the altered -catenin-dependent responses in injury. This proposal tests the hypothesis that epithelial -catenin signaling protects against CKD progression by protective effects on inflammation, oxidative stress, and cell cycle progression in a manner partly dependent on FoxO. The first aim investigates how epithelial -catenin signaling alters epithelial survival through effects on inflammation, cell cycle, and antioxidant production using murine models of injury. We will use genetically modified mice that have a mutation in -catenin that prevents its degradation, and this mutant -catenin is either specifically expressed in the proximal tubule or present throughout the tubule in a doxycycline-inducible manner. We will induce chronic kidney injury by either angiotensin/uninephrectomy or aristolochic acid. We anticipate that mice with increased epithelial -catenin activity have reduced inflammation, altered cell cycle progression, reduced oxidative stress, and increased epithelial survival after injury. We have identified a number of potential -catenin targets that may mediate these effects based on our preliminary data. We will measure expression of these targets in the injured animal models and test how they affect cell death using cell culture techniques. The second aim explores the role of FoxO in mediating -catenin's protective effect after chronic kidney injury. We will determine how injury (i.e. oxidative stress) alters the way -catenin signals to promote FoxO- mediated responses using a special reporter mouse. We will also cross our mouse containing the active - catenin in the proximal tubule with our mouse lacking FoxO in the same epithelial segment. If the benefit of - catenin activity is mediated through FoxO, then this double conditional knockout mouse should lose the protective effect (i.e. more epithelial cell death) conferred by augmented -catenin activity. Furthermore, we will define how FoxO targets change epithelial responses to stress using cell culture techniques. This proposal uses innovative genetic approaches to determine the role of -catenin and FoxO interactions in epithelial injury. We will investigate several novel targets of these protein interactions identified by sequencing the transcriptome (preliminary data). These studies will provide valuable pre-clinical data for these targets which may lead to future therapies for CKD. In addition, these studies will further our knowledge of Wnt/-catenin signaling and the role of FoxO in CKD.

慢性肾病 (CKD) 是一个日益严重的公共卫生问题，影响超过 10% 的退伍军人、 增加发病率和死亡率，并带来巨大的经济负担。 肾小管间质纤维化 (TIF) 的重要组成部分，而 TIF 是任何病因的进行性 CKD 的共同特征。 生长因子如转化生长因子- (TGF-) 和 Wnt/-连环蛋白是重要的决定因素 肾小管上皮如何响应损伤。Wnt/-连环蛋白途径的各种抑制剂具有混合效应。 我们使用遗传方法来增强近曲小管中的 β-连环蛋白信号传导，以及 这导致肾损伤后 CKD 进展显着改善。 我们的初步数据表明，β-连环蛋白与损伤和稳态的作用非常不同。 转录因子 FoxO 可能是损伤中 β-连环蛋白依赖性反应改变的重要介质。 该提案检验了上皮 -连环蛋白信号传导通过以下方式预防 CKD 进展的假设： 对炎症、氧化应激和细胞周期进程的保护作用部分取决于 福克斯O。 第一个目的是研究上皮 -连环蛋白信号如何通过影响上皮细胞存活来改变上皮细胞存活。 我们将使用小鼠损伤模型来研究炎症、细胞周期和抗氧化剂的产生。 修饰小鼠的 -连环蛋白发生突变，可防止其降解，这种突变的 -连环蛋白是 要么在近端小管中特异性表达，要么在多西环素诱导的整个小管中存在 我们将通过血管紧张素/单肾切除术或马兜铃酸诱导慢性肾损伤。 预计上皮 β-连环蛋白活性增加的小鼠可以减少炎症，改变细胞周期 我们已经确定了一个 根据我们的初步数据，我们将确定可能介导这些影响的潜在 -连环蛋白靶点的数量。 测量这些靶标在受伤动物模型中的表达，并使用细胞测试它们如何影响细胞死亡 培养技术。 第二个目的是探讨 FoxO 在介导慢性肾损伤后 β-catenin 的保护作用中的作用。 我们将确定损伤（即氧化应激）如何改变 -连环蛋白信号以促进 FoxO- 我们还将使用含有活性 - 的小鼠进行杂交。 近曲小管中的连环蛋白与我们的小鼠在同一上皮段中缺乏 FoxO 如果 - 的好处。 连环蛋白活性是通过 FoxO 介导的，那么这种双重条件敲除小鼠应该失去 增强的 β-连环蛋白活性所带来的保护作用（即更多的上皮细胞死亡）。 定义 FoxO 目标如何使用细胞培养技术改变上皮细胞对应激的反应。 该提案使用创新的遗传方法来确定 -catenin 和 FoxO 的作用 我们将研究这些已确定的蛋白质相互作用的几个新靶标。 通过对转录组进行测序（初步数据），这些研究将为以下方面提供有价值的临床前数据。 这些目标可能会导致未来的 CKD 治疗方法。此外，这些研究将进一步加深我们的认识。 Wnt/-连环蛋白信号传导以及 FoxO 在 CKD 中的作用。