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.

抽象的 急性肾脏损伤后的结果（AKI）涵盖了从完全恢复到失败的维修和 过渡到慢性肾脏疾病。 66岁及以上的Medicare患者住院的AKI 在一年内复发AKI住院的累积概率为35％，有28％的慢性 住院后的一年（“ AKI到CKD过渡”）。我们的工作 实验室和其他人已经证明，近端小管通过受伤引起的推导来维修 成熟的近端小管细胞。近端小管的基本特征提高了增殖 能力，但是管理这一过程的机制尚未完全理解。此外，在 严重或重复的损伤，近端小节上皮在细胞周期的G2/m期被捕， 导致纤维化的细胞因子分泌，细胞间质纤维化和CKD。这个长期目标 应用是定义代理小管细胞周期进程的分子机制，并测试是否是否 可以操纵这以促进成功维修。我们已经确定了特定而强大的上调 在受伤的代理管中受伤后的转录因子叉子盒蛋白M1（FOXM1） 随后的下调到第14天。FOXM1驱动与增殖相关基因的转录，并调节 细胞周期的G1/S和G2/M相。我们表明上皮生长因子受体（EGFR） 在体外和体内调节FOXM1表达，并敲除原发性肾脏近端中的FOXM1 地铁上皮细胞（RPTEC）抑制细胞增殖。近端小管中的EGFR激活也已知 激活与是相关的蛋白质（YAP）和茶域转录因子（TEAD），从而调节 AKI后的细胞增殖。根据已发布和初步数据，我们建议AKI导致EGFR- 通过AKT和YAP/TEAD对FOXM1的依赖性更新，从而导致亲修复近端细胞增殖。我们 进一步假设，可以预防近端小管中的修复和纤维化的G2/m停滞 可诱导的FOXM1表达，推动G2转录程序，细胞周期进程和成功修复。 在AIM 1中，我们检查了EGFR，HIPPO和FOXM1信号网络在近端小管上皮中的作用。在 AIM 2，我们定义了使用条件的缺血再灌注损伤后FOXM1在成功修复中的作用 删除策略。在AIM 3中，我们询问组成性活性FOXM1的管特异性，瞬态表达 （FOXM1ΔN）可以挽救促纤维化G2/M细胞周期停滞并修复失败。