Generation of New Mouse Models of Low Nephron Numbers to Understand Pathogenesis of AKI and CKD in Humans Born Preterm

生成新的低肾单位数小鼠模型，以了解早产人类 AKI 和 CKD 的发病机制

基本信息

批准号：
10066348
负责人：
FANGMING LIN
金额：
$ 42.43万
依托单位：
COLUMBIA UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-02-15 至 2022-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10066348
关键词：
Acute Renal Failure with Renal Papillary Necrosis Address Adult Alleles Amino Acids Animal Model Autophagocytosis Biology Biopsy Specimen Blood Pressure Caring Cells Chemicals Chronic Chronic Kidney Failure Clinical Consumption Data Development Dose Dropout Endowment Engineering Ensure Environment Female Financial compensation Future General Population Generations Gentamicins Goals Human Hypertension Hypertrophy Hypoxia Incidence Injury Injury to Kidney Investigation Kidney Kidney Diseases Knowledge Lead Life LoxP-flanked allele Measurable Measures Medical Metabolic Metabolic stress Metanephric Diverticulum Modeling Molecular Mus Mutate Neonatal Nephrectomy Nephrons Newborn Infant Pathogenesis Pathologic Pharmaceutical Preparations Phenotype Physiological Play Population Predisposition Pregnancy Premature Infant Protein Tyrosine Kinase Proteins Quality Control RET gene Rattus Recording of previous events Recovery Renal Hypertension Renal tubule structure Reperfusion Injury Risk Role Severities Stress Structure System Testing Tetanus Helper Peptide Virulence Factors absorption biological adaptation to stress chemical genetics clinically relevant cohort design genetic approach high risk inhibitor/antagonist injury and repair kidney biopsy mouse model mutant nephrogenesis nephrotoxicity novel offspring operation prevent renal hypoxia response severe injury small molecule inhibitor success

项目摘要

Abstract The population of humans born preterm (~24-37 w gestation) is growing rapidly as a result of advanced medical care. Unfortunately, humans born before 36 w gestation have incomplete kidney development and low nephron numbers, which has been hypothesized to cause increased risk of chronic kidney disease (CKD) and hypertension later in life. Premature infants also have a high incidence of acute kidney injury (AKI). Due to limited animal models and few kidney biopsy samples, the pathogenesis of AKI and CKD as well as the cellular response to kidney injury and repair in this population is poorly understood. We have developed new mouse models of congenital low nephron numbers (50-70% of controls) by inhibiting Ret tyrosine kinase during kidney development. Preliminary studies showed that kidneys with low nephron numbers had an accelerated AKI to CKD transition following ischemia-reperfusion injury (IRI). Since low nephron numbers is known to cause glomerular hyperfiltration and higher metabolic demands for absorption of high filter load of Na+ at the single nephron level, we examined kidneys for stress response with autophagy. We found that kidneys with low nephron numbers were more hypoxic and had higher autophagic response 4 w post-IRI. Therefore, we have planned studies to test the following hypotheses: 1) Low renal reserve in underdeveloped kidneys contributes to high risk of CKD, and 2) High metabolic stress may exceed autophagic compensation and lead to CKD development. Aim 1 will generate and validate new mouse models with a range of low nephron numbers (25-70% of control) that resemble human underdeveloped kidneys. We will take novel chemical and genetic approaches using mice harboring a floxed and mutant Ret allele that renders it susceptibility to a small molecule inhibitor. We plan to inhibit the engineered Ret activity with the chemical inhibitor or delete Ret gene specifically in the ureteric bud during mid-late gestation. Kidney development and renal structure and function will be characterized. Aim 2 We will use these new mouse models to address the questions of whether kidneys with low nephron numbers: 1) are more susceptible to AKI with more severe injury and incomplete recovery, and 2) have increased risk of CKD in the absence of prior history of AKI or more rapid CKD development after AKI exposure. We will also study clinically relevant models of neonatal AKI using newborn mice with low nephron number to test the impact of AKI on the developing kidneys. Aim 3 will characterize autophagy as a stress response to hypoxia and metabolic perturbations in underdeveloped kidneys by examining the role of autophagy in cell quality control as well as during the AKI to CKD transition. Studies are designed to test whether a decline in autophagic capacity and flux in response to physiologic and pathologic stress contributes to CKD development, and whether reducing metabolic stress delays CKD development. The overall goal is to obtain much needed knowledge that could be used in the future to prevent and treat kidney disease in the growing population of humans born preterm.

抽象的由于先进的医疗。不幸的是，在36 W妊娠之前出生的人类的肾脏发育不完整，肾单位数低，已经假设会导致慢性肾脏疾病（CKD）的风险增加和以后的高血压。早产婴儿也患有急性肾脏损伤（AKI）的发病率很高。到期的对于有限的动物模型和很少的肾脏活检样本，AKI和CKD的发病机理以及该人群中对肾脏损伤和修复的细胞反应知之甚少。我们已经开发了新的先天性低肾单位数（50-70％对照）的小鼠模型，通过抑制RET酪氨酸激酶在肾脏发育期间。初步研究表明，肾单位数低的肾脏具有在缺血 - 再灌注损伤（IRI）之后，加速了AKI到CKD转变。由于低肾单数为已知会引起肾小球过滤和较高的代谢需求，以吸收高过滤器载荷 Na+在单个肾单位水平上，我们检查了肾脏是否有自噬的应力反应。我们发现肾脏数量低的肾脏更缺氧，自噬反应较高4 W-iri后IRI。因此，我们计划了研究以下假设的研究：1）欠发达的低肾脏储备肾脏会导致CKD的高风险，2）高代谢压力可能会超过自噬补偿并导致CKD开发。 AIM 1将生成和验证具有一系列低范围的新鼠标模型类似于人类欠发达的肾脏的肾单位数（占对照的25-70％）。我们将把小说使用带有floxed and突变的RET等位基因的小鼠进行化学和遗传方法对小分子抑制剂的敏感性。我们计划使用化学药品抑制工程的RET活动妊娠中期妊娠期间，抑制剂或删除在输尿管芽中的RET基因。肾脏发展和肾脏结构和功能将被表征。 AIM 2我们将使用这些新鼠标模型来解决肾脏数量低的肾脏是否更容易受到AKI的影响，更严重受伤和不完全康复，2）在没有AKI或其他病史的情况下，CKD的风险增加 AKI暴露后，CKD开发更快。我们还将研究新生儿的临床相关模型 AKI使用肾单位较低的新生小鼠测试AKI对发育中的肾脏的影响。目的 3将自动噬是对欠发达中缺氧和代谢扰动的压力反应通过检查自噬在细胞质量控制以及AKI到CKD过渡期间的作用来肾脏。研究旨在测试自噬能力和通量的下降，以应对生理和病理压力有助于CKD发展，以及减少代谢压力是否会延迟CKD 发展。总体目标是获得急需的知识，以便将来使用以防止并治疗不断增长的人群的肾脏疾病出生的早产。