Molecular Mechanism of THM1-Medicated Renal Cystogenesis

THM1介导的肾囊肿发生的分子机制

• 批准号: 8534222
• 负责人: Pamela Vivian Tran
• 金额: $ 21.86万
• 依托单位: UNIVERSITY OF KANSAS MEDICAL CENTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8534222
• 关键词: Ablation; Adult; Alien; Alleles; Bardet-Biedl Syndrome; Cells; Clinical; Cyst; Cystic Kidney Diseases; Cystic kidney; Defect; Development; Distal; Duct (organ) structure; Embryo; Embryonic Development; Epithelial Cells; Epithelium; Erinaceidae; Ethylnitrosourea; Etiology; Exhibits; Fluorescence-Activated Cell Sorting; Gene Expression; Genes; Genetic; Goals; Grant; In Vitro; Instruction; Joubert syndrome; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; Measures; Mediating; Modeling; Molecular; Mus; Mutant Strains Mice; Mutate; Nephronophthisis; Nephrons; Pathogenesis; Pathway interactions; Patients; Perinatal; Phenotype; Physiology; Prevention strategy; Proteins; Regulation; Role; Severities; Signal Pathway; Sorting - Cell Movement; Stromal Cells; Syndrome; Testing; Thoracic Diseases; Time; Transcription Coactivator; Tubular formation; cell type; ciliopathy; design; inhibitor/antagonist; insight; interstitial cell; mouse model; mutant; novel; paracrine; prevent; research study; small molecule; smoothened signaling pathway; tool

Cysfic kidney disease (CKD) is proposed to originate from an underlying ciliary defect, though molecular mechanisms remain unclear. We have identified a novel ciliary protein, THM1 (Tetratricopeptide Repeat Containing Hedgehog Modulator 1, also termed TTC21B or IFT139), which negatively regulates Hedgehog (Hh) signaling. Recently, THM1 has been shown to contribute the most pathogenic alleles among ciliary genes to patients with ciliopathies, including Meckel-Gruber Syndrome (MKS), Bardet-Bledl Syndrome (BBS), nephronophthisis (NPHP), Joubert's Syndrome (JS) and Jeune's Asphyxiating Thoracic Disorder (JATD). A major clinical feature of these ciliopathies is CKD, and indeed, genetic deletion of Thml during late embryogenesis results in CKD in the adult mouse. While Hh signaling has not been studied extensively in CKD, our analyses of THM1 have led us to investigate a possible role for enhanced Hh activity in renal cystogenesis. In support of this hypothesis, cyst formation in an embryonic culture model of CKD was prevented by genetic deletion of Gli2, the main transcriptional activator of Hh signaling, and by treatment with small molecule Hh inhibitors. The goal of this proposal is to determine whether enhanced Hh activity leads to renal cysts. In the first aim, the effect of paracrine Hh signaling in CKD will be elucidated by conducting a spatial and temporal quantitative assessment of Hh signaling in the Thm1 conditional knock-out mouse. In the second aim, this spatial analysis will be extended by examining the effects of ablating Thm1 in renal tubular epithelial cells versus in renal stromal cells. In the third aim, causality of increased Hh signaling in renal cystogenesis will be explored by down regulating the Hh pathway genetically and pharmacologically in Thm1 conditional knock-out mice. Examining gene expression in a spatial context may provide a tool with which to gain better understanding of the pathogenesis of CKD. Furthermore, these experiments will establish a causal role for Hh signaling in renal cystogenesis and may offer important implications for the design of preventive strategies against CKD.

囊性肾病（CKD）被认为起源于潜在的纤毛缺陷，但分子机制仍不清楚。我们发现了一种新型纤毛蛋白 THM1（含有 Hedgehog 调节剂 1 的四肽重复序列，也称为 TTC21B 或 IFT139），它可以负向调节 Hedgehog (Hh) 信号传导。最近，THM1 已被证明在纤毛病患者的纤毛基因中贡献了最具致病性的等位基因，包括梅克尔-格鲁伯综合征 (MKS)、巴代-布莱德尔综合征 (BBS)、肾结核 (NPHP)、朱伯特综合征 (JS) 和 Jeune 窒息性胸廓疾病 (JATD)。这些纤毛病的一个主要临床特征是 CKD，事实上，胚胎发生晚期期间 Thml 的基因缺失会导致成年小鼠出现 CKD。虽然 Hh 信号传导在 CKD 中尚未得到广泛研究，但我们对 THM1 的分析使我们研究了 Hh 活性增强在肾囊肿发生中的可能作用。为了支持这一假设，通过基因删除 Gli2（Hh 信号转导的主要转录激活因子）和小分子 Hh 抑制剂治疗，可以阻止 CKD 胚胎培养模型中囊肿的形成。该提案的目的是确定 Hh 活性增强是否会导致肾囊肿。第一个目标是，通过对 Thm1 条件敲除小鼠中的 Hh 信号进行空间和时间定量评估，阐明旁分泌 Hh 信号在 CKD 中的作用。在第二个目标中，将通过检查消除 Thm1 在肾小管上皮细胞与肾基质细胞中的影响来扩展这种空间分析。第三个目标是，通过在 Thm1 条件性敲除小鼠中从遗传和药理学角度下调 Hh 通路，探索肾囊肿发生中 Hh 信号传导增强的因果关系。在空间背景下检查基因表达可能提供一种工具，可以更好地了解 CKD 的发病机制。此外，这些实验将确定 Hh 信号在肾囊肿发生中的因果作用，并可能为 CKD 预防策略的设计提供重要意义。