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Therapeutic potential of base editing strategies to convert CAG to CAA in Huntington's Disease

将 CAG 转化为 CAA 的碱基编辑策略在亨廷顿病中的治疗潜力

基本信息

批准号：
10318916
负责人：
Jong-Min Lee
金额：
$ 55.86万
依托单位：
MASSACHUSETTS GENERAL HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-12-15 至 2025-11-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10318916
关键词：
Affect Age Age of Onset Alleles Amino Acid Sequence Animal Model Biological Models Brain CAG repeat Cell Culture Techniques Cell model Cells Clinical Clinical Trials Clone Cells Clustered Regularly Interspaced Short Palindromic Repeats Code Corpus striatum structure DNA Repair Gene Data Development Disease Disease model Engineering Evaluation Future Gene Duplication Gene Targeting Gene-Modified Genes Genetic Glutamine Heritability Human Huntington Disease Huntington gene Huntington protein Interruption Investigation Knock-in Mouse Knowledge Length Liver Location Methods Modeling Modification Molecular Mus Mutation Neuronal Differentiation Neurons Nuclear Onset of illness Outcome Patients Persons Phenotype Plant Roots Positioning Attribute Research Role Route Specificity Stains Study models Symptoms Testing Therapeutic Treatment Efficacy Variant Work base base editing base editor clinical investigation clinically relevant clinically significant effective therapy genome editing genome wide association study genome-wide induced pluripotent stem cell innovation insight molecular phenotype mouse model novel novel therapeutics pre-clinical prevent therapeutic target therapeutically effective transcriptome sequencing treatment strategy virtual

项目摘要

SUMMARY / ABSTRACT Therapeutic potential of base editing strategies to convert CAG to CAA in Huntington's disease Huntington's disease (HD) defies development of effective treatments despite its long-known genetic cause and numerous mechanisms implicated in model systems, reflecting limited clinical utility of model-based investigations. By contrast, observations in HD patients may reveal therapeutics that actually works in people. All cases of HD are due to an expanded CAG repeat in huntingtin gene. However, age at clinical manifestation varies widely, and unexplained variance in age at onset by the mutation size shows heritability, indicating HD is modified by genes. Therefore, we performed genome-wide association study, and discovered that repeat instability-related DNA repair genes modify HD onset. Importantly, we revealed that duplicated and loss of CAG-CAA interruption in the huntingtin CAG repeat robustly delay and hasten HD onset age, respectively. Together, our data indicate that the rate of HD is largely determined by the size of uninterrupted CAG repeat and modified by repeat instability, providing insights into driver of the disease and therapeutic strategies. Capitalizing on these clinically relevant observations in humans, we conceived novel therapeutic Base Editing (BE) strategies to convert CAG to CAA aiming at delaying clinical manifestation by decreasing the size of uninterrupted CAG repeat and potentially further suppressing repeat expansion. Our novel therapeutic BE strategies have a number of advantages over other gene targeting approaches. Observations in patients suggest that CAG-to-CAA conversion produces very strong therapeutic benefit (i.e., delaying onset more than 10 years). In addition, our BE strategies, targeting the root cause of the disease, do not alter huntingtin protein since both CAG and CAA encode glutamine. Therefore, same single treatment strategies can be applied to all HD patients to produce allele-specific benefits. Here, we propose to determine therapeutic potential of selected BE strategies to convert CAG to CAA using relevant cell and animal models of HD. Briefly, we will 1) evaluate conversion efficiencies and allele specificity of BE strategies with high efficiencies, 2) test whether CAG-to- CAA conversion affects HTT expression levels, neuronal differentiation, and other molecular phenotypes, 3) determine impacts of CAG-to-CAA conversion on CAG repeat instability, and 4) evaluate off-target effects, and further optimize to reveal the BE strategy with the highest feasibility and therapeutic potential. This research will 1) produce a complete evaluation chart for combinations of different base editors and conversion strategies, 2) generate knowledge regarding allele specificity, off-targeting, and molecular consequences, 3) provides considerations for subsequent optimization, and 4) produce expected outcomes when BE strategies are applied to HD patients. Our research testing novel and innovative therapeutic routes for HD therefore will significantly contribute to the development of effective therapeutics for HD and other CAG expansion disorders.

摘要/摘要