AAV Progranulin Gene Therapy for Lysosomal Brain Disorders
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Solution Overview
Problem
Current treatments for Gaucher disease and fronto-temporal dementia with GRN mutation are inadequate in addressing neurological manifestations and skeletal issues, with no disease-modifying therapies available for fronto-temporal dementia.
Innovation Solution
Administration of a recombinant adeno-associated virus (rAAV) vector encoding the progranulin (PGRN) protein, utilizing specific promoters, enhancers, and capsid proteins, delivered via the cisterna magna, to enhance PGRN expression in the brain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If enzyme replacement therapy, chaperone drugs, or substrate reduction therapy are used to treat Gaucher disease, then peripheral disease symptoms are improved, but neurological manifestations and skeletal issues remain refractory to treatment
Solution Approach 1:
The invention segments the treatment approach by using different AAV serotypes (AAV1, AAV2, AAV5, AAV8, AAV9) to target different tissues and pathways. Each serotype has specific tropism characteristics that allow selective delivery of functional GBA1 gene to peripheral tissues, CNS, or both, thereby addressing both peripheral and neurological manifestations through segmented delivery strategies
Solution Approach 2:
The invention introduces AAV vectors as intermediary carriers to deliver functional GBA1 cDNA across the blood-brain barrier and into target cells. The AAV capsid proteins act as mediators that facilitate neuronal uptake and intracellular delivery of the therapeutic gene, enabling CNS penetration that traditional enzyme replacement therapy cannot achieve
2Reliability
If traditional therapies are administered, then peripheral manifestations are addressed, but no disease-modifying effect is achieved for neurological symptoms
Solution Approach 1:
The invention performs preliminary action by delivering functional GBA1 cDNA via AAV vectors before irreversible neurological damage occurs. The early gene delivery establishes sustained endogenous enzyme production in CNS cells, preventing progression of neurological symptoms rather than merely managing existing symptoms
Solution Approach 2:
The invention ensures continuity of useful action through sustained expression of functional GBA1 enzyme from the delivered cDNA. The AAV-mediated gene transfer creates persistent enzyme production in target cells, providing continuous therapeutic effect that lasts throughout the patient's lifetime rather than requiring repeated administrations
3Reliability
If GRN haploinsufficiency is present, then 90% risk of developing FTD-GRN occurs, but no disease-modifying therapies are available
Solution Approach 1:
The invention uses copying by delivering a functional copy of the GRN gene (cDNA) via AAV vectors to compensate for the defective endogenous GRN allele. This functional copy is integrated into the patient's cells and produces sufficient progranulin protein to prevent or delay FTD-GRN pathology, effectively creating a genetic backup for the haploinsufficient condition
Data Source
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AI summary
The disclosure relates to compositions and methods for treatment of diseases associated with aberrant lysosomal function, such as fronto-temporal dementia (FTD). The disclosure also provides expression constructs comprising a transgene encoding progranulin or a portion thereof. The disclosure provides methods of treating FTD by administering such expression constructs to a subject in need thereof.