G2 - Immune Targeting and Approaches with Genetically-Modified Cells and Cell Therapies (Including CAR-T, CAR-NK, TCR editing)
88: Development of a FAP-CAR T Cell Protocol to Reduce Skeletal Muscle Fibrosis in a Murine Model of Duchenne Muscular Dystrophy
Type: Oral Abstract Session
Presentation Details
Session Title: CAR T and Other Genetically Modified Immune Cells
Fibrosis is a feature of Duchenne muscular dystrophy (DMD) which progressively weakens skeletal and cardiac muscles. Immunotherapy with fibroblast activating protein (FAP)-specific CAR T cells has already been used to reduce cardiac fibrosis in mice during a drug-induced condition but this approach has not been tested in muscular dystrophy. The DBA2mdx mouse is a model of severe DMD in which rapid and strong fibrosis is observed, characterized by dense collagen deposits in skeletal muscles, with over-expression of the FAP and Col3 genes in the TA, GA, EDL muscles at 2, 3, and 4 months of age compared to their aged-matched DBA2 littermates. We developed a third-generation mFAP-CAR lentiviral vector (LV) to generate mFAP-specific CAR T cells from DBA2 spleen T cells. The transduction conditions were initially established with a LV co-expressing the mFAP-CAR and a CD19 tag, but subsequently, the CD19 tag was removed to increase titer and transduction efficacy, as measured by provirus digital PCR. The specificity and potency of the mFAP CAR T cells was demonstrated on FAP-expressing 3T3 cells using cytotoxicity and degranulation assays. To evaluate their in vivo efficacy, mFAP-CAR T cells were adoptively transferred into DBA2mdx mice. Dose finding tests showed that at least two injections of 1xE+06 FAP-CAR-LV-transduced cells were necessary to significantly reduce the histological and molecular biomarkers of fibrosis in muscles, as measured 2 weeks post-cell injection by reduced Col3 and FAP mRNA expression. Altogether, these results establish a basal protocol to reduce muscle fibrosis in DBA2mdx mice. Further studies are warranted to understand the effects of FAP CAR T cells in this model. MF and CR contributed equally. IR and AG are co-senior authors of this study.
Plain Language Summary
Duchenne muscular dystrophy (DMD) is a muscle disease of genetic origin characterized by a progressive loss of muscle function and accompanied by the fibrosis of the muscle tissues. Fibrosis has negative effects and may hamper the gene therapy of DMD. We sought to reduce muscle fibrosis with genetically-engineered immune cells, the so-called CAR T cells, which have shown efficacy to kill various types of cells. We identified fibrosis markers that were highly expressed in a mouse model of DMD. We designed the tools and a protocol to generate fibrosis-specific killer CAR T cells in mice. When sufficient amounts of these CAR T cells were injected to mice with DMD, they reduced the hallmarks of fibrosis as demonstrated by histology and molecular analyses of the muscle tissues. Further studies are warranted to use CAR-T cells to improve the treatment DMD.
Maxime Ferrand1, Celine Rocca1, Sonia Albini1, Valentina Buffa1, Elodie Bôle-Richard2, Francine Garnache-Ottou2, Isabelle Richard1, Anne Galy1,3
1UMR_S951 Integrare Research Unit, Genethon, Evry-Courcouronnes, France,2UMR1098 RIGHT, Université Franche-Comté, EFS Besançon, Besançon, France,3Art-tg, Inserm, Corbeil-Essonnes, France"
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