Novel gene therapy strategies for Canavan disease

卡纳万病的新型基因治疗策略

• 批准号: 8731279
• 负责人: Guangping Gao
• 金额: $ 46.8万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8731279
• 关键词: Address; Affect; Antigen-Presenting Cells; Applications Grants; Area; Ashkenazim; Aspartic Acid; Aspartoacylase; Biodistribution; Blood - brain barrier anatomy; Brain; Canavan Disease; Capsid; Central Nervous System Diseases; Cessation of life; Childhood; Clinical; Clinical Research; Codon Nucleotides; Data; Defect; Demyelinations; Dependovirus; Development; Disease; Dose; Ethnic group; Foundations; Functional disorder; Future; Gene Delivery; Gene Expression; Gene Transfer; Generations; Genes; Genome; Head; Immunity; Inherited; Intervention; Intravenous; Kidney Diseases; Knockout Mice; Lead; Macrocephaly; Mediating; Metabolic; MicroRNAs; Mitochondria; Modeling; Motor; Mus; Muscle hypotonia; Mutation; Neurodegenerative Disorders; Neurons; Oligodendroglia; Outcome; Patients; Peripheral; Permeability; Phenotype; Population; Population Study; Prevalence; Recombinant adeno-associated virus (rAAV); Recombinants; Reporting; Research; Retinal Diseases; Role; Route; Safety; Seroprevalences; Serotyping; Spinal Cord; Swelling; Testing; Therapeutic; Tissues; Toxic effect; Transduction Gene; Transgenes; Treatment Efficacy; Work; adeno-associated viral vector; base; cell type; design; disease phenotype; effective therapy; follower of religion Jewish; gene correction; gene replacement therapy; gene therapy; human NAT2 protein; immunotoxicity; improved; infancy; intravenous injection; leukodystrophy; meetings; mouse model; myelination; neuropathology; novel; novel strategies; patient population; postnatal; prevent; promoter; repaired; research clinical testing; success; therapeutic gene; transduction efficiency; transgene expression; treatment strategy; vector; white matter

DESCRIPTION (provided by applicant): Canavan disease (CD) is a rare, inherited, and fatal, childhood leukodystrophy caused by autosomal recessive mutations in the aspartoacylase gene (ASPA). Although CD has been found in a wide range of ethnic groups, it is especially prevalent in the Ashkenazi Jewish population, affecting one in 6,400 - 13,500 people in this group. ASPA deficiency in Canavan patients leads to accumulation of N-Acetyl-Aspartic Acid (NAA), resulting in swelling and spongy degeneration of white matter in the brain. The clinical manifestations of this fatal disease includ psychomotor retardation, hypotonia, macrocephaly, head lag, and early death. NAA is synthesized in the mitochondria of neurons by N-acetyltransferase (NAT1) and hydrolyzed in oligodendrocytes (OLs) by ASPA. Pathogenic mechanism(s) of ASPA deficiency in the CNS and contributions of ASPA deficits in PTs to the pathophysiology of CD are not well studied. Currently, there is no effective clinical intervention available for CD. ASPA gene replacement therapy is an attractive strategy for the treatment of CD. Earlier gene therapy efforts based on the first generation of AAV serotype 2-derived vector offered no clinical benefit. That was likely due to inadequate transduction efficiency of rAAV2 and limitations of localized intraparenchymal vector delivery. Recent advances in AAV vectorology produced some novel recombinant AAVs (rAAVs), such as rAAV9 reported by Kaspar et al., and rAAVrh.8 and rh.10 identified by our lab, that are highly efficient in transducing large areas of the brain and spinal cord by crossing the blood-brain-barrier (BBB) after intravenous (IV) injection. Here, we hypothesize that using these novel vectors and route of administration, we can develop safe, effective, and sustained gene therapy strategies that will correct the metabolic defect, alleviate the disease phenotype, and prolong survival of CD mice without causing significant toxicity. Specifically, this project will further our understanding of the pathophysiology of CD, particularly in the PTs and the mechanism of rAAV-mediated CD gene therapy after intravenous delivery. We will compare the BBB permeability between wild type (Wt) and ASPA Knockout (ASPA-/-) mice, and define the latest therapeutic window for CD. We will optimize the transgene cassette to express hASPA more efficiently and safely. We will compare our 3 lead vectors (i.e. rAAV9, rh.8, and rh.10) in ASPA-/- mice for minimum effective dose, the latest therapeutic window, long lasting therapeutic outcomes, immunotoxicity, and biodistribution profiles. To facilitate future clinical development, we will also compare these 3 vectors for sero- prevalence in the CD patient population and study impact of pre-existing immunity on CNS gene therapy by adoptively transferring capsid immunities to ASPA-/- mice. These proposed studies will significantly advance our current understanding of CD, and serve as the basis for the development of safe and effective rAAV gene therapeutics for CD patients.

描述（由申请人提供）： 卡纳万病 (CD) 是一种罕见的遗传性致命性儿童脑白质营养不良，由天冬氨酸酰化酶基因 (ASPA) 的常染色体隐性突变引起。虽然 CD 在许多种族群体中都有发现，但在德系犹太人中尤其普遍，该群体中每 6,400 至 13,500 人中就有一人受到影响。 Canavan 患者的 ASPA 缺乏会导致 N-乙酰天冬氨酸 (NAA) 积聚，导致大脑白质肿胀和海绵状变性。这种致命疾病的临床表现包括精神运动迟缓、肌张力减退、巨头畸形、头部迟滞和过早死亡。 NAA 在神经元线粒体中由 N-乙酰转移酶 (NAT1) 合成，并在少突胶质细胞 (OL) 中由 ASPA 水解。 CNS 中 ASPA 缺乏的致病机制以及 PT 中 ASPA 缺乏对 CD 病理生理学的影响尚未得到充分研究。目前，尚无针对 CD 的有效临床干预措施。 ASPA 基因替代疗法是治疗 CD 的一种有吸引力的策略。早期基于第一代 AAV 血清型 2 衍生载体的基因治疗工作没有提供临床益处。这可能是由于 rAAV2 的转导效率不足以及局部实质内载体递送的限制。 AAV载体学的最新进展产生了一些新型重组AAV（rAAV），例如Kaspar等人报道的rAAV9，以及我们实验室鉴定的rAAVrh.8和rh.10，它们能够高效地转导大脑和脊髓的大面积区域静脉（IV）注射后通过血脑屏障（BBB）穿过脐带。在这里，我们假设使用这些新的载体和给药途径，我们可以开发安全、有效和持续的基因治疗策略，以纠正代谢缺陷，减轻疾病表型，并延长 CD 小鼠的生存期，而不引起明显的毒性。具体来说，该项目将进一步了解 CD 的病理生理学，特别是 PT 以及静脉注射后 rAAV 介导的 CD 基因治疗的机制。我们将比较野生型 (Wt) 和 ASPA 敲除 (ASPA-/-) 小鼠之间的 BBB 通透性，并确定 CD 的最新治疗窗口。我们将优化转基因盒，以更高效、更安全地表达 hASPA。我们将在 ASPA-/- 小鼠中比较我们的 3 个主要载体（即 rAAV9、rh.8 和 rh.10）的最小有效剂量、最新治疗窗口、持久治疗结果、免疫毒性和生物分布概况。为了促进未来的临床开发，我们还将比较这 3 种载体在 CD 患者群体中的血清流行率，并通过将衣壳免疫过继转移至 ASPA-/- 小鼠来研究预先存在的免疫对 CNS 基因治疗的影响。这些拟议的研究将显着增进我们目前对 CD 的理解，并为开发针对 CD 患者的安全有效的 rAAV 基因疗法奠定基础。