A novel all-in-one AAV system for efficient epigenome editing in neurodegenerative diseases

Unmet Need

Neurodegenerative diseases such as Alzheimer’s and Parkinson’s affect over 55 million people worldwide, with prevalence expected to double by 2050 due to aging populations. These conditions are progressive, debilitating, and currently have no cures. This places enormous burdens on patients, families, and healthcare systems. While gene therapy holds promise for addressing the underlying genetic drivers of these diseases, current approaches face significant challenges. These include off-target effects, permanent genomic alterations, and vector size limitations, which are especially problematic for safe and precise treatment in the brain. There is a need for a compact, durable, and non-destructive gene regulation system that enables suppression of neurodegenerative disease-associated genes with high specificity and minimal risk.

Technology

Duke inventors have developed an all-in-one gene repression system based on a compact AAV-delivered epigenome-editing platform. This is intended to be a therapeutic platform for modulating gene expression in neurodegenerative diseases such as Parkinson’s and Alzheimer’s. Furthermore, this approach—termed epigenome-editing—permits to treat a broad range of genetic diseases caused by dysregulation in gene expression through reversing disease-causing gene expression changes back to a normal state. In a clinical context, the system would be delivered via AAV injection to neurons, allowing researchers or clinicians to epigenetically silence disease-driving genes directly within the brain, using a single vector. Specifically, the inventors present a novel and compact expression cassette (AAV-CRISPR/dCas9-KRAB-MeCP2) that incorporates Sp1 and NF-κB enhancer elements to overcome AAV packaging limitations. This allows for the delivery of a complete epigenome editing system, including promoter, dSaCas9-KRAB-MeCP2 fusion, gRNA, and regulatory elements, within a single AAV vector. The KRAB-MeCP2 effector mediates robust and sustained transcriptional repression, offering a safer and more specific alternative to nuclease-active based editing. The system has been validated in human cell lines, where it effectively downregulated SNCA and APOE—genes associated with Parkinson’s disease and late-onset Alzheimer’s disease, respectively. In vivo, the technology was tested in mice and successfully suppressed gene expression for up to six weeks, demonstrating strong potential for long-term therapeutic effects.

Other Applications

This technology could also be applied to other areas such as cancer, metabolic disorders like hypercholesterolemia, and cell-type specific gene regulation in research.

Advantages

• All-in-one system fits within AAV packaging limits while maintaining high viral titers
• Novel and highly efficient bi-partite repressor comprising from KRAB and transcriptional repression domain (TRD) of MeCP2
• Effectively silences disease-relevant genes (SNCA, APOE) without cutting or altering the DNA
• Achieves robust and sustained gene silencing in both cell lines and mouse brain