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: 10672969
• 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/10672969
• 关键词: 19 year old; Adult; Age; Agonist; Alagille Syndrome; Alleles; Animal Diseases; 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; Functional Regeneration; Gene Expression Profiling; Genes; Genetic; Genetic Diseases; Genetic Models; Genetic Transcription; Growth; Hemorrhage; Hepatic; Hepatocyte; Hepatology; Heterozygote; Human; In Vitro; Life; Ligands; Liver; Liver Failure; Liver Regeneration; Locomotion; Loss of Heterozygosity; 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; Visualization; Zebrafish; autosome; bile duct; body system; cell regeneration; dosage; drug standard; effective therapy; efficacy evaluation; 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.

项目概要 阿拉吉尔综合征 (ALGS) 是一种常染色体显性遗传疾病，其特征是新生儿和成人多效性 由单倍体不足的 JAGGED/NOTCH 信号传导引起的病理 (1)。具体来说，ALGS 是由 杂合性功能丧失突变主要发生在 Notch 配体基因 JAGGED1 (JAG1) 中，较少发生 经常出现在 NOTCH2 (N2) (2-5) 中。尽管这种疾病的特点是多器官系统缺陷， 心血管和肝脏病变是最危及生命的。然而，这种基因的体内遗传模型 由于 Jag1 杂合小鼠的外显率轻微且可变，该疾病一直具有挑战性 (6)。更远， 目前还没有成熟的药物可以增强 Notch 信号传导以潜在地治疗这种遗传 紊乱。为了生成表型更加稳健的 ALGS 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，以产生始终如一的强而渗透的病理学 与 ALGS 类似，包括肝胆管缺乏无法解决和自发性出血。 此外，我们还验证了一种小分子Notch激动剂，可以直接增强Notch信号传导 哺乳动物细胞和斑马鱼。这些重要的新工具将使我们能够首次调查救援情况 Notch 信号传导作为这种单倍体不足的 Jag/Notch 信号传导遗传病的治疗方法。 在 ALGS 肝脏中，胆管细胞缺乏可导致胆汁淤积和肝功能衰竭。随着流行 对于那些没有进行肝移植的人，估计有 1/40,000 的出生率 (7) 和 19 岁时死亡率为 76% (8)、ALGS迫切需要有效的治疗。我们的斑马鱼体内研究首次表明 恢复锯齿状/Notch 信号传导可导致丢失的肝管细胞再生。这一发现，连同 Jagged1 杂合小鼠 (6, 9) 出生后肝管缺乏的恢复以及肝功能的波动 ALGS 患者 (10) 表明 ALGS 病理可能是可逆的。可逆性以及变量 ALGS 患者的动态病理外显率及其 JAG1 杂合性使我们得出以下假设 Jag/Notch 信号可能在不足和充足之间摇摆不定。因此，这些 ALGS 稍微增强Notch信号传导可能可以治疗病理。我们经过严格验证 一种新型小分子 Notch 激动剂，可强力增强小鼠肝细胞和 ALGS 中的 Notch 信号传导 具有 JAG1 突变的患者成纤维细胞。我们在此建议在斑马鱼中测试这种新近验证的 Notch 激动剂， 小鼠、人类 Jag ALGS 突变模型。我们的初步研究表明，这种 Notch 激动剂 确实能刺激 jag 突变斑马鱼的肝管细胞再生。我们的研究对于产出至关重要 使用Notch激动剂作为解决大多数生命问题的治疗策略的概念验证数据 威胁性 ALGS 病理。这些研究是临床前研究必要的基本步骤。