Live imaging analyses of the mechanisms required for coordinated urinary tract peristalsis in lower-order and higher-order mammalian species

低阶和高阶哺乳动物协调尿路蠕动所需机制的实时成像分析

基本信息

批准号：
10181186
负责人：
Romulo Hurtado
金额：
$ 3.39万
依托单位：
WEILL MEDICAL COLL OF CORNELL UNIV
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-03-01 至 2024-02-29
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10181186
关键词：
Ablation Address Anatomy Basic Science Bladder Cations Cells ChIP-seq Child Childhood Clinical Defect Development Diagnostic Disease Distal Excretory function Exhibits Family suidae Fetus Flare Functional disorder Genes Genetic Transcription Goals Homologous Gene Human Hydronephrosis Image Imaging Techniques Immunohistochemistry Impairment Injury Ion Channel Kidney Kidney Failure Mammals Mediating Mesenchyme Metanephric Diverticulum Morbidity - disease rate Mus Muscle Newborn Infant Optics Organ Pacemakers Pathology Pelvis Peristalsis Pharmaceutical Preparations Phenotype Physiological Physiology Play Procedures Process Property Publishing Renal Tissue Reporting Research Role Site Smooth Muscle System Techniques Testing Therapeutic Time Tissues Tubular formation Ureter Urinary tract Urine Video Microscopy antenatal clinical translation clinically significant human tissue hyperpolarization-activated cation channel imaging modality in vivo innovation insight mouse model mutant mutant mouse model novel novel therapeutics patch clamp pressure prevent ratiometric renal damage screening stem cells transcription factor wasting

项目摘要

ABSTRACT Proximal-to-distal peristaltic contractions of the upper urinary tract (UUT) smooth muscle coat propel waste from the kidney to the bladder. Defects in the peristaltic process are highly prevalent and clinically significant. For example, impaired urine outflow from the kidney causes pressure mediated dilation of renal tissues, or hydronephrosis. Hydronephrosis is the most commonly observed abnormality in children, detected in 1% of newborns, and is a leading cause of pediatric kidney failure. The overall goal of this project is to better understand the normal physiology and pathophysiology of the UUT. Indeed, despite the high morbidity associated with urinary tract dysfunctions, the mechanisms underlying renal pacemaker activity that triggers UUT peristalsis have remained elusive. To study this process, we have developed novel live imaging techniques to record the propagation of electrical and contractile excitation throughout the intact UUT. Results of our studies have revealed that hyperpolarization activate cation (HCN) channels are highly expressed and localized to renal pacemaker tissues of the murine UUT. HCN channel inhibition abolishes UUT pacemaker activity, and results in a loss of coordinated peristalsis. Instead of the proximal-to-distal contractile and electrical excitation observed in control UUTs, HCN inhibited explants exhibit near-simultaneous electrical activation throughout the UUT and twitch-like contractile activity. Thus, we have demonstrated ex-vivo that HCN+ cells of the UUT are renal pacemakers that set the origin and coordinate UUT peristalsis. Moreover, we have recently discovered that HCN channel expression is conserved to renal pacemaker tissues of the porcine and human urinary tracts, which share a unique anatomy and physiology. In Aim 1 of this proposal we will use a novel mouse model of hydronephrosis that lacks HCN+ cells in the UUT. We will use the live imaging techniques we have developed to determine if loss of HCN+ cells in vivo results in aberrant UUT peristalsis that underlies hydronephrosis. Aim 1 will also include mechanistic studies to begin to elucidate the transcriptional networks regulating HCN+ pacemakers. For Aim 2, we have recently developed a novel explant system to directly visualize the electrical and contractile properties of peristalsis in the porcine UUT. We will use this explant system to determine if HCN channel conductance is required for coordinated UUT peristalsis in a close homolog to humans. Results of these studies will provide much needed insight into the mechanisms underlying normal and aberrant UUT peristalsis in both lower-order and higher-order mammalian species. Long term translational implications of the studies include the development of novel treatments and diagnostics for uropathies such as hydronephrosis.

抽象的上尿路 (UUT) 平滑肌层的近端至远端蠕动收缩推动废物从肾到膀胱。蠕动过程中的缺陷非常普遍且具有临床意义。例如，肾脏的尿液流出受损会导致压力介导的肾组织扩张，或肾积水。肾积水是儿童中最常见的异常现象，1% 的儿童可发现肾积水新生儿，并且是小儿肾衰竭的主要原因。该项目的总体目标是更好地了解 UUT 的正常生理学和病理生理学。事实上，尽管发病率很高与尿路功能障碍相关，触发肾起搏器活动的机制 UUT 的蠕动仍然难以捉摸。为了研究这个过程，我们开发了新型实时成像记录整个完整 UUT 中电和收缩激励传播的技术。结果我们的研究表明，超极化激活阳离子 (HCN) 通道高度表达，并且定位于小鼠 UUT 的肾起搏器组织。 HCN 通道抑制废除了 UUT 起搏器活动，并导致协调蠕动的丧失。而不是从近端到远端的收缩和在对照 UUT 中观察到电激发，HCN 抑制的外植体表现出近乎同步的电激发整个 UUT 的激活和抽搐样收缩活动。因此，我们已经在体外证明了 UUT 的 HCN+ 细胞是肾起搏器，可设置原点并协调 UUT 蠕动。此外，我们最近发现HCN通道表达在猪的肾起搏器组织中是保守的和人类泌尿道，它们具有独特的解剖学和生理学。在本提案的目标 1 中，我们将使用一种新型肾积水小鼠模型，其 UUT 中缺乏 HCN+ 细胞。我们将使用实时成像我们开发的技术用于确定体内 HCN+ 细胞的损失是否会导致 UUT 蠕动异常是肾积水的基础。目标 1 还将包括机制研究，以开始阐明转录调节 HCN+ 起搏器的网络。对于目标 2，我们最近开发了一种新型外植体系统直接可视化猪 UUT 中蠕动的电气和收缩特性。我们将使用这个外植体系统以确定是否需要 HCN 通道电导来协调 UUT 的近距离蠕动与人类同源。这些研究的结果将为了解其背后的机制提供急需的见解低阶和高级哺乳动物物种中正常和异常的 UUT 蠕动。长期这些研究的转化意义包括开发新的治疗方法和诊断方法尿路疾病，例如肾积水。