Liver-directed AAV gene therapy for PHKG2-Glycogen Storage Disease IX (GSD IX y2)

针对 PHKG2-糖原贮积病 IX (GSD IX y2) 的肝脏定向 AAV 基因治疗

• 批准号: 10315138
• 负责人: Rebecca Anne Gibson
• 金额: $ 3.82万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10315138
• 关键词: Accounting; Address; Adolescent; Age-Months; Albumins; Blood Glucose; Breeding; Capsid; Case Study; Cells; Cessation of life; Child; Childhood; Cirrhosis; Clinical; Clinical Trials; Complex; Corn starch preparation; Data; Dependovirus; Diagnosis; Diet Modification; Dietary Intervention; Disease; Disease Progression; Disease model; Doctor of Philosophy; Dose; Enzymes; Female; Fibrosis; Future; Genes; Genetic; Glucose; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type IX; Goals; Hepatocyte; Hepatomegaly; Human; Hypoglycemia; Immune response; Immunohistochemistry; Immunosuppression; Individual; Ketones; Knock-out; Knockout Mice; Laboratories; Life; Liver; Liver Failure; Liver Fibrosis; Liver Glycogen; Liver diseases; Mission; Modeling; Mus; National Institute of Child Health and Human Development; Pathway interactions; Patients; Phenotype; Phosphorylase Kinase; Physicians; Prevalence; Primary carcinoma of the liver cells; Protein Isoforms; Proteins; Public Health; Publishing; Quantitative Reverse Transcriptase PCR; Recombinant adeno-associated virus (rAAV); Reporting; Research; Risk; Scientist; Serotyping; Serum; Severities; Testing; Therapeutic; Time; Tissues; Transgenes; Tropism; Urine; Viral Vector; Weight; adeno-associated viral vector; base; bench to bedside; career; clinical translation; efficacy evaluation; enzyme activity; exome sequencing; gene therapy; glycogenolysis; high risk; in vivo; innovation; interdisciplinary collaboration; intravenous injection; liver function; liver injury; liver transplantation; male; minimally invasive; mouse model; novel; pre-clinical; preclinical efficacy; preclinical evaluation; promoter; symptomatic improvement; transduction efficiency; uncooked; vector

Liver Glycogen Storage Disease type IX has an overall estimated prevalence of 1 in 100,000 individuals, accounting for approximately 25% of all GSD cases. Liver GSD IX is caused by deficiency of the liver enzyme phosphorylase kinase (PhK) and presents with hepatomegaly, elevated liver enzymes, and hypoglycemia. PhK is a complex, hetero-tetrameric enzyme comprised of four subunits - α, β, γ, and δ - each with tissue specific isoforms encoded by different genes. The genes PHKA2, PHKB, and PHKG2 encode the liver specific isoform PhK subunits α2, β, and γ2 respectively. Until the recent availability of gene panels and exome sequencing, the diagnosis of Liver GSD IX did not allow for differentiation of these subtypes. There is growing evidence that patients with the second most common subtype, PHKG2 GSD IX (GSD IX γ2) develop severe liver disease. Of published case reports, 95.8% of patients with GSD IX γ2 reported features of liver fibrosis and/or cirrhosis, placing individuals with GSD IX γ2 at higher risk for liver failure, hepatocellular carcinoma and death. Despite the life-threatening severity of GSD IX γ2, there has been minimal research to understand disease progression or options for treatment. The first goal of this project is to characterize the phenotype of the first mouse model of PHKG2 GSD IX (GSD IX γ2). Preliminary evidence from male and female 3-month-old Phkg2-/- mice is encouraging. I have discovered that knockout mice have significantly elevated liver glycogen content, serum ALP, AST, ALT, urine Hex4, and features of hepatocyte enlargement and fibrosis compared to wild type controls. I will continue to characterize the Phkg2-/- mouse phenotype at 6, 9- and 12-months of age. By identifying the time of onset and progression of liver disease in our model, I will better understand the ideal time to deliver therapy. The second goal of this project is to evaluate the efficacy of a novel AAV gene therapy approach for reducing liver disease progression in the Phkg2-/- mouse model. Current liver-directed gene therapies utilize a recombinant adeno-associated virus serotype 8 (AAV8), based on preclinical efficacy in mice. However, recent studies have demonstrated that AAV8 has greater tropism for murine versus human hepatocytes. Our group has identified a novel capsid with high transduction rates for both human and murine hepatocytes (AAVhum.8) – making it an excellent vector for preclinical evaluation with high potential for clinical translation. The results of this project will characterize the first GSD IX γ2 mouse model, will provide preclinical evidence for a non-surgical, long-term, therapeutic option for patients with GSD IX γ2, and will inform the treatment of other pediatric genetic liver diseases.

肝糖原储存疾病IX类型的总体估计患病率为100,000人中有1个患病率，约占所有GSD病例的25％。肝脏GSD IX是由肝酶激酶（PHK）缺乏引起的，并伴有肝肿大，肝酶升高和低血糖。 PHK是一种复杂的，异四聚酶，由四个亚基组成 - α，β，γ和δ-每个亚基，每个亚基均具有由不同基因编码的组织特异性同工型。 PHKA2，PHKB和PHKG2基因分别编码肝脏特异性同工型PHK亚基α2，β和γ2。在最近的基因面板和外显子组测序的可用性之前，肝GSD IX的诊断不允许分化这些亚型。越来越多的证据表明，患有第二常见亚型PHKG2 GSD IX（GSDIXγ2）患者患有严重的肝病。在已发表的病例报告中，有95.8％的GSDIXγ2患者报告了肝纤维化和/或肝硬化的特征，使患有GSDIXγ2的个体面临肝脏衰竭，肝细胞癌和死亡的较高风险。尽管GSDIXγ2的严重程度危及生命，但仍有最少的研究了解疾病的进展或治疗方案。该项目的第一个目标是表征PHKG2 GSD IX（GSDIXγ2）的第一个小鼠模型的表型。男性和女性3个月大的PHKG2 - / - 小鼠的初步证据令人鼓舞。我发现，与野生型对照相比，敲除小鼠具有显着升高的肝糖原含量，血清ALP，AST，ALT，尿液HEX4，以及肝细胞膨胀和纤维化的特征。我将继续表征6、9和12个月的PHKG2 - / - 小鼠表型。通过在我们的模型中确定肝病的发作和进展时间，我将更好地了解提供治疗的理想时间。该项目的第二个目标是评估新型AAV基因治疗方法在降低PHKG2 - / - 小鼠模型中肝病进展的有效性。基于小鼠的临床前效率，当前肝脏指导的基因疗法利用重组腺相关的病毒血清型8（AAV8）。然而，最近的研究表明，鼠与人肝细胞的AAV8对鼠的最向最大主义。我们的小组已经确定了一种新型的衣壳，对人和鼠肝细胞的翻译率很高（Aavhum.8） - 使其成为临床前评估的绝佳载体，具有临床翻译的高潜力。该项目的结果将表征第一个GSDIXγ2小鼠模型，该模型将为GSDIXγ2患者提供非手术，长期，治疗选择的临床前证据，并将告知其他儿科遗传肝病的治疗。