Augmented Notch signaling as a therapeutic approach for Alagille Syndrome

增强型 Notch 信号传导作为 Alagille 综合征的治疗方法

• 批准号: 10504974
• 负责人: P. Duc Si Dong
• 金额: $ 42.9万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10504974
• 关键词: 19 year old; Adult; Age; Agonist; Alagille Syndrome; Alleles; Animals; Attenuated; Automobile Driving; Bile fluid; Biliary; Bilirubin; Binding; Biological Assay; Birth; Cardiac; Cardiovascular system; Cell Nucleus; Cells; Chlorides; Cholestasis; Data; Defect; Development; Dextrans; Disease; Disease model; Drug Kinetics; Duct (organ) structure; Ductal Epithelial Cell; Enhancers; Extracellular Domain; Fibroblasts; Gene Expression Profiling; Genes; Genetic; Genetic Diseases; Genetic Models; Genetic Transcription; Growth; Hemorrhage; Hepatic; Hepatocyte; Hepatology; Heterozygote; Human; In Vitro; Lead; Life; Ligands; Liver; Liver Failure; Liver Regeneration; Locomotion; Mammalian Cell; Modeling; Mus; Mutation; Natural regeneration; Neonatal; Nucleic Acid Regulatory Sequences; Pathologic; Pathology; Patient-Focused Outcomes; Patients; Penetrance; Pharmaceutical Preparations; Phenotype; Play; Prevalence; Recovery; Regimen; Role; Signal Transduction; Testing; Therapeutic; Time; Toxic effect; Vascular Permeabilities; Zebrafish; bile duct; body system; cell regeneration; dosage; drug standard; effective therapy; genetic approach; histological studies; improved; in vivo; liver function; liver transplantation; loss of function mutation; mortality; mouse model; mutant; notch protein; overexpression; postnatal; preclinical study; receptor; small molecule; tool; transcriptome sequencing

Project Summary Alagille Syndrome (ALGS) is an autosomal dominant disorder characterized by pleiotropic neonatal and adult pathologies resulting from haploinsufficient JAGGED/NOTCH signaling (1). Specifically, ALGS is caused by heterozygous loss-of-function mutations predominantly in the Notch ligand gene, JAGGED1 (JAG1), and less frequently, in NOTCH2 (N2) (2-5). Although this disorder is characterized by defects in multiple organ systems, cardiovascular and hepatic pathologies are the most life-threatening. However, in vivo genetic modeling of this disease has been challenging due to the mild and variable penetrance of Jag1 heterozygous mice (6). Further, there is currently no well-established drug that can enhance Notch signaling to potentially treat this genetic disorder. To generate a more phenotypically robust vertebrate model of ALGS, we leveraged the zebrafish model to control the genetic dosage of jagged alleles to produce consistently strong and penetrant pathologies analogous to ALGS, including failure of liver bile duct paucity to resolve and spontaneous hemorrhaging. Moreover, we have validated a small molecule Notch agonist that can directly enhance Notch signaling in mammalian cells and in zebrafish. These critical new tools will allow us for the first time to investigate the rescuing of Notch signaling as a therapeutic approach for this haploinsufficient Jag/Notch signaling genetic disease. In the ALGS liver, bile duct cell paucity can lead to cholestasis and liver failure. With a prevalence estimated at 1/40,000 births (7) and a 76% mortality rate by the age of 19 years for those without a liver transplant (8), ALGS urgently requires an effective treatment. Our zebrafish in vivo studies reveal for the first time that restoring Jagged/Notch signaling leads to regeneration of the lost liver duct cells. This discovery, together with postnatal recovery of liver duct paucity in Jagged1 heterozygous mice (6, 9) and fluctuations in liver function in ALGS patients (10), suggest that ALGS pathologies may be reversible. The reversibility, as well as the variable and dynamic pathological penetrance in ALGS patients and their JAG1 heterozygosity, led us to the hypothesis that Jag/Notch signaling may be teetering between being insufficient and sufficient. Therefore, these ALGS pathologies may potentially be treatable with a slight augmentation of Notch signaling. We rigorously validated a new small molecule Notch agonist that can robustly enhance Notch signaling in mouse livers cells and ALGS patient fibroblasts with JAG1 mutations. We propose here to test this newly validated Notch agonist in zebrafish, mouse, human Jag mutant models of ALGS. Our emerging preliminary studies reveal that this Notch agonist does indeed stimulate liver duct cell regeneration in jag mutant zebrafish. Our studies will be critical to yield proof-of-concept data for the use of a Notch agonist as a therapeutic strategy for resolving the most life- threatening ALGS pathologies. These studies are necessary fundamental steps towards pre-clinical studies.

项目摘要 阿拉吉综合征（ALGS）是一种常染色体显性疾病，其特征是多效新生儿和成人 由单倍体锯齿状/缺口信号传导产生的病理（1）。具体而言，ALG是由 杂合的功能丧失突变主要在Notch配体基因，JAGGED1（JAG1）中，而更少 通常，在Notch2（N2）（2-5）中。尽管这种疾病的特征是多个器官系统中的缺陷，但 心血管和肝病病是最危及生命的。但是，体内遗传建模 由于JAG1杂合小鼠的轻度和可变渗透性，疾病一直具有挑战性（6）。更远， 当前没有建立的药物可以增强缺口信号传导来潜在地治疗这种遗传 紊乱。为了生成更具表型的ALG脊椎动物模型，我们利用了斑马鱼模型 控制锯齿状等位基因的遗传剂量以产生始终如一的渗透性病理 类似于ALG，包括肝脏胆管导致缺乏解决和自发出血。 此外，我们已经验证了一个小分子缺口激动剂，可以直接增强Notch信号传导 哺乳动物细胞和斑马鱼。这些关键的新工具将使我们首次调查救援 Notch信号作为这种单倍于这种单倍的JAG/Notch信号遗传疾病的治疗方法。 在ALGS肝脏中，胆管细胞的缺乏会导致胆汁淤积和肝衰竭。患病率 估计有1/40,000的出生（7）和76％的死亡率，到19岁时，没有肝脏移植者 （8）ALG紧急需要有效的治疗。我们的斑马鱼体内研究首次揭示了 恢复锯齿状/缺口信号传导导致失去的肝管细胞再生。这个发现，以及 JAGGED1杂合小鼠（6，9）中肝管道缺乏的产后恢复（6）和肝功能波动 ALGS患者（10）表明ALGS病理可能是可逆的。可逆性以及变量 ALGS患者及其JAG1杂合性的动态病理渗透性使我们提出了假设 JAG/Notch信号传导可能在不足和足够之间摇摆。因此，这些ALG 通过略有增强Notch信号传导，病理可能可以治疗。我们严格验证 一种新的小分子缺口激动剂，可以强烈地增强小鼠肝细胞和ALG中的Notch信号传导 具有JAG1突变的患者成纤维细胞。我们在这里建议在斑马鱼中测试这种新验证的Notch激动剂， 小鼠，人体锯齿突变模型。我们新兴的初步研究表明，这种缺口激动剂 确实确实刺激了Jag突变斑马鱼中的肝管细胞再生。我们的研究对于屈服至关重要 概念验证数据用于使用凹槽激动剂作为解决最终寿命的治疗策略 - 威胁ALG的病理。这些研究是临床前研究的必要基本步骤。