Developing an inducible mouse model for gene replacement therapy in Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD)

开发用于琥珀半醛脱氢酶缺乏症 (SSADHD) 基因替代疗法的诱导小鼠模型

基本信息

批准号：
10380224
负责人：
Alexander Rotenberg
金额：
$ 22.13万
依托单位：
BOSTON CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2023-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10380224
关键词：
Address Age Animal Model Ataxia Biology Blood Body Fluids Bolus Infusion Brain Brain Injuries Brain region Breeding Catabolism Cells Chlorides Clinical Clinical Research Depressed mood Development Developmental Delay Disorders Disease Dose Down-Regulation Doxycycline Elderly Encephalopathies Enterobacteria phage P1 Cre recombinase Enzymes Epilepsy Family member Frequencies Functional disorder Future GABA Receptor Genes Genetic Recombination Grant Growth Immunohistochemistry Injections Intellectual functioning disability Internal Ribosome Entry Site Interneurons Intraperitoneal Injections Introns Knockout Mice Lead Life Liver Measures Mediating Medical Metabolic Diseases Modeling Mouse Strains Mus Mutation Natural History Neurons Neurotransmitters Outcome Pathologic Patients Phenocopy Phenotype Preclinical Testing Protocols documentation Readiness Recombinant adeno-associated virus (rAAV)Regulation Risk Seizures Signal Transduction Site Specificity Succinate-semialdehyde dehydrogenase deficiency Survival Rate Symptoms Terminator Codon Testing Tetracyclines Therapeutic Time Tissues Trans-Activators Treatment Efficacy Urine Viral Vector Wild Type Mouse age related aldehyde dehydrogenases cell type enzyme activity enzyme deficiency enzyme replacement therapy extracellular gamma hydroxybutyrate gamma-Aminobutyric Acid gene replacement therapy gene therapy improved insight intraperitoneal mortality motor deficit mouse model novel overexpression postnatal development pre-clinical preclinical development proteostasis receptor receptor downregulation receptor expression receptor-mediated signaling reconstitution response restoration risk variant sudden unexpected death in epilepsy translational study

项目摘要

Project summary/abstract (30 lines) Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD) is a rare inborn metabolic disorder caused by aldh5a1 mutations. Aldh5a1 encodes SSADH which is essential for the catabolism of the inhibitory neurotransmitter γ-aminobutyric acid (GABA). In SSADHD, pathologic accumulation of GABA and its metabolite γ-hydroxybutyrate (GHB) leads to broad spectrum encephalopathy. Paradoxically, despite ambient GABA is heightened, SSADHD patients are susceptible to seizures and sudden unexpected death in epilepsy (SUDEP), highlighting the significance of compensatory GABA receptor reduction over pathologic GABA build- up. A major unmet medical need for SSADHD is treatment directly addressing the underlying enzyme deficiency such as enzyme replacement therapy (ERT) and gene therapy. Proof-of-concept systemic ERT and liver-directed aldh5a1 over-expression increased aldh5a1-/- mice survival. However, enzyme or viral vector injections in aldh5a1-/- mice lead to uncontrollable, non-specific SSADH restoration difficult to evaluate therapeutic efficacy and dose-response relationship. It is unclear restoring SSADH at what time, rate or in what cell types would suffice for phenotype reversal. We thus propose to develop a novel mouse model which allows conditional aldh5a1 reactivation under independent Cre or doxycycline regulation. In this novel mouse strain, aldh5a1 gene activity is disrupted at basal level, but is reconstituted upon Cre-mediated recombination or is reversibly regulated by the level of doxycycline. Our specific aims in this two-year exploratory grant are to: 1) Develop the aldh5a1lox-rtTA-STOP mouse model and characterize its baseline phenotype trajectory across development. 2) Test for an age-dependent therapeutic window when SSADH restoration is safe and effective, by injecting AAV-Cre into this mouse at contrasting developmental time points. 3) Test whether abrupt SSADH restoration leads to epileptic seizures, and whether gradual SSADH restoration has a therapeutic advantage, by injecting single dose versus multiple lower doses of AAV-Cre across days in early postnatal development. 4) Test whether inhibitory cell-directed partial SSADH restoration might be sufficient for phenotype reversal, by breeding aldh5a1lox-rtTA-STOP mice with Gad2-IRES-Cre mice. This novel mouse model enables testing of preclinical readiness of SSADH-restoring strategies such as gene therapy and ERT in a controlled, quantifiable and cell-specific manner. This project's long-term objectives are two-fold: 1) Provision of mechanistic insights into SSADH pathophysiology and how SSADH restoration might rescue symptoms. The proposed mouse model allows conditional SSADH depletion and restoration, so that pathological mechanisms of SSADHD and the impacts of SSADH restoration can be studied in great details. 2) Establishment of key parameters for therapeutic SSADH restoration. The proposed model provides necessary insights into the dose, pace and cell-specificity of SSADH restoration, advancing future translational and clinical studies including ERT and gene therapy for SSADHD patients.

项目摘要/摘要（30行）琥珀酸半甲醛脱氢酶缺乏症（SSADHD）是由罕见的先天代谢疾病 Aldh5A1叛变神经递质γ-氨基植物帐户（GABA）。代谢产物γ-羟基丁酸（GHB）导致广泛的脑病 GABA是Qeighted的，SSADHD患者对癫痫发作的癫痫发作和突然意外死亡。（SUDEP），强调了补偿GABA受体重新赔偿的重要性向上。缺乏酶替代疗法（ERT）和基因疗法。肝导向ALDH5A1过表达的ALDH5A1 - / - 小鼠存活。在Aldh5A1中注射---小鼠导致无法控制的，非特异性的SSADH休息障碍，以促进治疗功效和剂量反应关系。细胞类型足以逆转表型。允许有条件的ALDH5A1重新激活不见不见的CRE或强力霉素调节。菌株，ALDH5A1基因活性在基础水平上被破坏，但在CRE介导的重组后重新生成或受多西环素水平的可逆调节。 TO：1）开发Aldh5a1lox-rtta-stop Mousel并表征其基线表型轨迹开发。在对比的发育时间点上，将AAV-CRE注入该小鼠中有效。突然的ssadh恢复会导致癫痫发作，以及逐渐的ssadh休息治疗优势，通过在早期注射单剂量与多种较低剂量的AAV-CRE 产后发育。足以使表型逆转，通过用GAD2-IRES-CRE小鼠繁殖Aldh5A1lox-RTTA-Stop小鼠。 Mousel模型可以测试SSADH期间策略的临床前读数，例如基因疗法疗法和以受控的，可量化的细胞特异性方式进行ERT。 1）提供对萨德病理生理学的机理见解以及萨德氏恢复如何可能救援症状。可以细节研究SSADHD的病理机制和SSADH休息的影响。 2）建立用于治疗的SSADH恢复的关键参数。对SSADH恢复的剂量，节奏和细胞特异性的必要见解，促进未来翻译和临床研究包括包括SSADHD患者的ERT和基因治疗。