Pathogenesis of tubule atrophy and failed recovery after acute kidney injury

急性肾损伤后肾小管萎缩及恢复失败的发病机制

基本信息

批准号：
9198226
负责人：
MANJERI A VENKATACHALAM
金额：
$ 34.31万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-01-01 至 2019-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9198226
关键词：
Acute Renal Failure with Renal Papillary Necrosis Address Atrophic Autophagocytosis BRCA1 gene Cell Proliferation Cells Chronic Chronic Kidney Failure DNA DNA Damage DNA Double Strand Break DNA Repair DNA biosynthesis DNA-dependent protein kinase Data Defect Deoxyribonucleotides Development Dialysis procedure Environment Event Exhibits FRAP1 gene Fibrosis GADD45A gene Gamma-H2AX Gene Expression Genes Genetic Transcription Growth H2AFX gene HIF1A gene Health Healthcare Hypoxia Immunohistochemistry Impairment Incidence Inflammation Infusion procedures Intervention Investigation Kidney Kidney Diseases Laboratories MAPK14 gene MAPK8 gene Measures Messenger RNA Morbidity - disease rate Mus Natural regeneration Nuclear Oxygen Pathogenesis Pathology Phenotype Phosphotransferases Plant Roots Proliferating Protein Analysis Proteomics Publishing RNA Probes RNA analysis Recovery Renal tubule structure Reperfusion Injury Reporter Research Ribonucleotide Reductase Ribonucleotides Risk Role Signal Transduction Signaling Protein Stress Structure TSC2 gene Testing Transgenes Transgenic Organisms Transplantation Undifferentiated Western Blotting Work base deoxyribonucleoside triphosphate homologous recombination hypoxia inducible factor 1 in vivo innovation insight knock-down morphometry mortality new therapeutic target overexpression prevent programs public health relevance recombinational repair repaired response transcriptome sequencing tripolyphosphate

项目摘要

DESCRIPTION (provided by applicant): Tubule atrophy and fibrosis often develop after acute kidney injury (AKI) favoring transition to chronic kidney disease (CKD). The AKI-CKD transition has major implications, but poorly understood. We found that tubules regenerating after AKI often fail to differentiate. Such tubules are growth arrested and atrophic, and exhibit signaling that drives fibrosis. The cause of this pathology is unknown. We obtained three lines of evidence that could explain why recovering tubules become atrophic and profibrotic. First, tubules showed damage to DNA and DNA damage repair responses (DDR) during ischemic AKI, and then, instead of subsiding, DNA damage and DDRs persisted into later stages of tubule atrophy and fibrosis. Altered gene expression caused by DNA damage may explain why tubules fail to recover normally. Chronic hypoxia in kidneys recovering from AKI could inhibit oxygen dependent ribonucleotide reductase (RNR) in tubules causing depletion of deoxynucleotide triphosphates (dNTPs) and thereby produce DNA damage. Second, dNTPs declined in hypoxic cultured tubule cells, producing DNA damage and DDRs. This was accompanied by growth arrest and a dedifferentiated abnormally signaling profibrotic phenotype similar to that seen during tubule atrophy after AKI in vivo. Provision of dNTP precursors ameliorated the hypoxic DNA damage and reversed the growth arrest. Third, by RNAseq transcriptional profiling of hypoxic cells, we identified increased expression of genes related to inflammation, atrophy and fibrosis. Our hypothesis is that following ischemic AKI, chronic hypoxia inhibits ribonucleotide reductase (RNR) in regenerating tubules, depletes dNTPs, and, thereby, causes DNA replication stress and DNA damage. Because DNA damage is chronic, the DNA damage repair response (DDR) also persists, giving rise to inflammation, atrophy and fibrosis. To test this hypothesis, we have three Specific Aims. In Aim 1 we will explore the relationships between DNA damage and development of tubule atrophy using immunohistochemistry and morphometry, a transgenic reporter DNA damage, and inducible deletion of critical DDR genes to investigate if the intervention modifies late pathology after AKI In Aim 2, we will investigate the relationships of hypoxic inhibition of RNR, dNTP depletion, DNA damage/DDR and cell pathology. We will determine if infusions of dNTP precursors in vivo ameliorate tubule pathology after AKI. In Aim 3, we will use RNAseq and proteomics to selectively identify hypoxic alterations specific to dNTP depletion as apart from other hypoxic effects. Thus, we hope to provide critically needed information relating to basic aspects in the pathogenesis of a major health problem, chronic kidney disease.

描述（由适用提供）：急性肾损伤（AKI）经常出现小管萎缩和纤维化，这有利于过渡到慢性肾脏疾病（CKD）。 Aki-CKD过渡具有重大影响，但理解很少。我们发现，在AKI之后再生的块茎通常无法区分。这样的块茎正在增长，萎缩和萎缩，并暴露于驱动纤维化的信号传导。这种病理的原因是未知的。我们获得了三条证据，可以解释为什么恢复管变成萎缩和纤维化。首先，在缺血性AKI期间，试管对DNA和DNA损伤修复反应（DDR）显示出损害，然后，DNA损伤和DDR持续到了管萎缩和纤维化的后期。由DNA损伤引起的基因表达改变可能解释了为什么试管无法正常恢复。从AKI中恢复的肾脏中的慢性缺氧可以抑制依赖性氧气核苷酸还原（RNR），导致脱氧核苷酸三磷酸盐（DNTPS）耗竭，从而产生DNA损伤。其次，在低氧培养的小管细胞中DNTP下降，产生DNA损伤和DDR。这是通过越来越多的停滞和类似于Aki in aki在体内的小节萎缩期间的纯正信号传导纤维化表型来实现的。 DNTP前体的提供可以改善低氧DNA损伤并逆转生长停滞。第三，通过RNASEQ的转录分析低氧细胞，我们确定了与感染，萎缩和纤维化有关的基因表达的增加。我们的假设是，遵循缺血性AKI，慢性低氧抑制核糖核苷酸还原酶（RNR）在再生小管，耗尽DNTPS中，从而造成DNA复制应力和DNA损伤。由于DNA损伤是慢性的，因此DNA损伤修复反应（DDR）也持续存在，从而导致感染，萎缩和纤维化。为了检验这一假设，我们有三个具体的目标。在目标1中，我们将使用免疫组织化学和形态计量学，转基因报告基因DNA损伤以及关键DDR基因的可诱导缺失，以研究AIM 2中AKI后的晚期病理学是否在AIM 2中研究，我们将研究RNR损伤和DNA DRA的关系，DNA损伤的关系是否会研究，DNA损伤是否会研究rnrnr的关系，DNA损伤与DNA损伤，DNA损伤及其DRN损伤，DNA损伤是否可以研究，DNA损害的后期病理是否会调查，DNA损伤是否会调查，DNA损伤是否会调查，DNA损伤是否会调查DRN和DDA的关系。我们将确定在AKI之后，DNTP前体的输注是否可以改善小管病理学。在AIM 3中，我们将使用RNASEQ和蛋白质组学来选择性地识别DNTP部署特异性的缺氧变化，除其他缺氧作用外。这，我们希望提供与主要健康问题（慢性肾脏疾病）发病机理中基本方面有关的急需信息。