Mechanisms of Successful vs. Failed Kidney Repair

肾脏修复成功与失败的机制

• 批准号: 10385841
• 负责人: BENJAMIN D. HUMPHREYS
• 金额: $ 38.22万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10385841
• 关键词: Acute; Acute Renal Failure with Renal Papillary Necrosis; Adult; Automobile Driving; Back; Binding; Cell Cycle; Cell Cycle Arrest; Cell Cycle Progression; Cell Proliferation; Cells; Chronic Kidney Failure; Complex; Data; Defect; Down-Regulation; Epithelial; Epithelial Cells; Event; Fibrosis; G2/M Arrest; Genes; Genetic Transcription; Goals; Growth Factor Receptors; Hospitalization; In Vitro; Injury; Injury to Kidney; Investigation; Kidney; Laboratories; M cell; Mediating; Medicare; Mitosis; Modeling; Molecular; Nuclear; Outcome; Pathway interactions; Patients; Phosphotransferases; Probability; Process; Proteins; Proto-Oncogene Proteins c-akt; Proximal Kidney Tubules; Publishing; Receptor Activation; Recovery; Recurrence; Regulator Genes; Reperfusion Injury; Role; Signal Transduction; Tea; Testing; Therapeutic Intervention; Up-Regulation; Work; aged; base; epithelial repair; falls; forkhead protein; improved; in vivo; injured; kidney repair; knock-down; mouse model; novel therapeutic intervention; prevent; profibrotic cytokine; programs; recruit; repaired; response to injury; transcription factor

ABSTRACT Outcomes after acute kidney injury (AKI) cover a wide spectrum ranging from full recovery to failed repair and transition to chronic kidney disease. Medicare patients aged 66 years and older who were hospitalized for AKI had a 35% cumulative probability of a recurrent AKI hospitalization within one year and 28% developed chronic kidney disease (CKD) in the year following hospitalization (the “AKI to CKD transition”). Work from our laboratory and others has demonstrated that proximal tubule repairs through injury-induced dedifferentiation of mature proximal tubule cells. A cardinal feature of proximal tubule dedifferentiation is increased proliferative capacity, but the mechanisms governing this process are incompletely understood. Moreover, in cases of severe or repetitive injury, proximal tubule epithelia become arrested in the G2/M phase of the cell cycle, leading to profibrotic cytokine secretion, tubulointerstitial fibrosis and CKD. The long term goal of this application is to define the molecular mechanisms of proximal tubule cell cycle progression and test whether this can be manipulated to promote successful repair. We have identified the specific and strong upregulation of the transcription factor forkhead box protein M1 (FoxM1) in injured proximal tubule after injury with subsequent downregulation by day 14. FoxM1 drives transcription of proliferation-related genes, and regulates both G1/S and G2/M phases of the cell cycle. We show that the epithelial growth factor receptor (EGFR) regulates FoxM1 expression both in vitro and in vivo, and knockdown of FoxM1 in primary renal proximal tubule epithelial cells (RPTECs) inhibits cell proliferation. EGFR activation in proximal tubule is also known to activate Yes-Associated Protein (Yap) and Tea Domain transcription factors (TEAD) which in turn regulates cell proliferation after AKI. Based on published and preliminary data, we propose that AKI leads to EGFR- dependent upregulation of FoxM1 via AKT and Yap/TEAD, causing pro-repair proximal tubule proliferation. We further hypothesize that failed repair and profibrotic G2/M arrest in proximal tubule can be prevented by inducible FoxM1 expression, driving a G2 transcriptional program, cell cycle progression and successful repair. In Aim 1 we examine the roles of EGFR, Hippo and FoxM1 signaling networks in proximal tubule epithelia. In Aim 2, we define the role of FoxM1 in successful repair after ischemia-reperfusion injury using a conditional deletion strategy. In Aim 3 we ask whether tubule-specific, transient expression of constitutively active FoxM1 (FoxM1∆N) can rescue pro-fibrotic G2/M cell cycle arrest and failed repair.

摘要 急性肾损伤（阿基）后的结局涵盖了从完全恢复到修复失败的广泛范围， 向慢性肾病转变。因阿基住院的66岁及以上的Medicare患者 一年内阿基复发住院的累积概率为35%，28%的患者发生慢性 在住院后的一年中，患者患有肾脏疾病（CKD）（“阿基向CKD过渡”）。从我们的工作 实验室和其他人已经证明，近端小管通过损伤诱导的去分化修复， 成熟近曲小管细胞。近曲小管去分化的一个主要特征是增殖性增加 能力，但这一进程的机制并不完全了解。此外，如果 严重或重复性损伤，近端小管上皮细胞停滞在细胞周期的G2/M期， 导致促纤维化细胞因子分泌、肾小管间质纤维化和CKD。长期目标是 应用是定义近端小管细胞周期进展的分子机制，并测试是否 这可以被操纵以促进成功的修复。我们已经确定了特定的和强烈的上调 转录因子叉头盒蛋白M1（FoxM 1）在损伤的近端小管损伤后， 随后在第14天下调。FoxM 1驱动增殖相关基因的转录，并调节 细胞周期的G1/S和G2/M期。我们发现，上皮生长因子受体（EGFR） 在体外和体内调节FoxM 1的表达，并在原发性肾近端细胞中敲低FoxM 1。 肾小管上皮细胞（RPTEC）抑制细胞增殖。还已知近端小管中的EGFR活化 激活Yes相关蛋白（雅普）和茶结构域转录因子（TEAD），进而调节 阿基后的细胞增殖。根据已发表的和初步的数据，我们认为阿基导致EGFR- 通过AKT和雅普/TEAD依赖性上调FoxM 1，引起促修复近端小管增殖。我们 进一步假设近端小管中的修复失败和促纤维化G2/M阻滞可以通过以下方式预防： 诱导型FoxM 1表达，驱动G2转录程序，细胞周期进展和成功修复。 在目的1中，我们研究了EGFR、Hippo和FoxM 1信号网络在近端小管上皮中的作用。在 目的2，我们使用条件性的免疫组织化学方法，确定FoxM 1在缺血再灌注损伤后成功修复中的作用。 删除策略在目的3中，我们询问组成型活性FoxM 1的小管特异性瞬时表达是否 （FoxM 1-N）可以挽救促纤维化G2/M细胞周期停滞和修复失败。