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FAP-CAR-T cells reduce dystrophic muscle fibrosis, improving adeno-associated virus gene transfer efficacy
Maxime Ferrand1,2, Céline J Rocca1,2, Guillaume Corre1,2
1Université Paris-Saclay, Univ Evry, Inserm, Integrare Research Unit UMR_S951, Genethon, 91000 Evry-Courcouronnes, France.
Abstract:
Tissue fibrosis is a pathological feature of many diseases including muscular dystrophies such as Duchenne muscular dystrophy (DMD). Fibrosis may limit the effectiveness of gene therapy in muscle impacting on viral dosing but direct evidence is lacking. Strategies to reduce skeletal muscle fibrosis are limited. The fibrosis Fap gene is over-expressed in the skeletal muscles of a severe mouse model of DMD, suggesting that cells expressing membrane fibroblast activation protein (FAP) could be targeted by chimeric antigen receptor (CAR)-T cells. Two consecutive administrations of FAP-specific CAR-T cells in the severe DMD model reduced collagen deposits and fibrotic biomarkers and also reduced the number of FAP-positive cells in muscle. Single cell transcriptomics revealed that FAP-CAR-T cells triggered cellular interactions with otherwise inactive muscle resident macrophages and depleted specific subsets of FAP-highly-expressing fibro-adipogenic progenitor cells, pointing to their importance in the fibrosis process. Reducing fibrosis with FAP-CAR-T cells enhanced adeno-associated virus (AAV) microdystrophin gene transfer in the model by increasing vector copies, demonstrating that fibrosis is a restriction factor for AAV gene delivery in skeletal muscle. These results provide novel insights into therapeutic strategies for DMD or other fibrotic diseases.
Insights
Chimeric antigen receptor (CAR)-T cells targeting fibroblast activation protein (FAP) reduced fibrosis in a Duchenne muscular dystrophy (DMD) mouse model. This approach improved gene therapy delivery, demonstrating FAP-CAR-T cells
Area of Science:
- Immunology
- Genetics
- Cell Biology
Background:
- Tissue fibrosis is a hallmark of diseases like Duchenne muscular dystrophy (DMD), potentially hindering gene therapy efficacy.
- Current strategies for reducing skeletal muscle fibrosis are limited.
- The fibrosis gene fibroblast activation protein (FAP) is overexpressed in DMD skeletal muscle.
Purpose of the Study:
- To investigate the therapeutic potential of targeting FAP-expressing cells using chimeric antigen receptor (CAR)-T cells in a severe mouse model of DMD.
- To determine if reducing fibrosis can enhance adeno-associated virus (AAV) gene transfer efficiency in skeletal muscle.
Main Methods:
- Administration of FAP-specific CAR-T cells in a severe DMD mouse model.
- Assessment of collagen deposits, fibrotic biomarkers, and FAP-positive cell counts.
- Single-cell transcriptomics to analyze CAR-T cell interactions and effects on cellular populations.
- Evaluation of AAV microdystrophin gene transfer efficiency post-treatment.
Main Results:
- Two administrations of FAP-CAR-T cells significantly reduced collagen deposits and fibrotic biomarkers.
- CAR-T cell treatment decreased the number of FAP-positive cells and modulated muscle resident macrophages.
- Specific subsets of FAP-highly-expressing fibro-adipogenic progenitor cells were depleted.
- Reduced fibrosis led to enhanced AAV microdystrophin gene transfer by increasing vector copies.
Conclusions:
- FAP-specific CAR-T cell therapy is a promising strategy to reduce skeletal muscle fibrosis in DMD.
- Fibrosis acts as a restriction factor for AAV gene delivery in skeletal muscle.
- Targeting FAP-expressing cells offers a novel therapeutic avenue for DMD and other fibrotic diseases.
