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Updated: May 28, 2026
CRISPR/Cas9 Technology in Restoring Dystrophin Expression in iPSC-Derived Muscle Progenitors
Published on: September 14, 2019
A simplified immune suppression scheme leads to persistent micro-dystrophin expression in Duchenne muscular dystrophy
Jin-Hong Shin1, Yongping Yue, Arun Srivastava
1Department of Molecular Microbiology and Immunology, University of Missouri , Columbia, Missouri 65212, USA.
Abstract:
Highly abbreviated micro-dystrophin genes have been intensively studied for Duchenne muscular dystrophy (DMD) gene therapy. Following adeno-associated virus (AAV) gene transfer, robust microgene expression is achieved in murine DMD models in the absence of immune suppression. Interestingly, a recent study suggests that AAV gene transfer in dystrophic dogs may require up to 18 weeks' immune suppression using a combination of three different immune-suppressive drugs (cyclosporine, mycophenolate mofetil, and anti-dog thymocyte globulin). Continued immune suppression is not only costly but also may cause untoward reactions. Further, some of the drugs (such as anti-dog thymocyte globulin) are not readily available. To overcome these limitations, we developed a novel 5-week immune suppression scheme using only cyclosporine and mycophenolate mofetil. AAV vectors (either AV.RSV.AP that expresses the heat-resistant human alkaline phosphatase gene, or AV.CMV.μDys that expresses the canine R16-17/H3/ΔC microgene) at 2.85×10(12) vg particles were injected into adult dystrophic dog limb muscles under the new immune suppression protocol. Sustained transduction was observed for nearly half year (the end of the study). The simplified immune suppression strategy described here may facilitate preclinical studies in the dog model.
Insights
A simplified immune suppression strategy using cyclosporine and mycophenolate mofetil for Duchenne muscular dystrophy (DMD) gene therapy in dogs shows sustained microgene expression. This approach reduces the duration and complexity of immunosuppression for preclinical studies.
Area of Science:
- Gene Therapy
- Immunology
- Duchenne Muscular Dystrophy Research
Background:
- Adeno-associated virus (AAV) gene transfer is a promising therapy for Duchenne muscular dystrophy (DMD).
- Previous studies in dystrophic dogs suggested a prolonged 18-week immune suppression protocol was necessary for AAV gene transfer, involving multiple drugs.
- This lengthy immunosuppression is costly, can cause adverse reactions, and utilizes drugs with limited availability.
Purpose of the Study:
- To develop a simplified and shorter immune suppression protocol for AAV gene therapy in dystrophic dogs.
- To evaluate the efficacy of a novel 5-week immune suppression regimen using only cyclosporine and mycophenolate mofetil.
- To assess sustained gene expression following AAV vector delivery under the new protocol.
Main Methods:
- Developed a novel 5-week immune suppression regimen using cyclosporine and mycophenolate mofetil.
- Administered AAV vectors (expressing alkaline phosphatase or micro-dystrophin) at 2.85×10^12 vg particles to adult dystrophic dog limb muscles.
- Monitored gene transduction and expression for up to six months.
Main Results:
- Achieved sustained gene transduction for nearly six months in dystrophic dogs.
- Demonstrated the efficacy of the simplified 5-week immune suppression protocol.
- Confirmed successful expression of micro-dystrophin and alkaline phosphatase genes.
Conclusions:
- A simplified 5-week immune suppression strategy using cyclosporine and mycophenolate mofetil is effective for AAV gene therapy in dystrophic dogs.
- This approach overcomes limitations of previous lengthy and complex immunosuppression protocols.
- The findings facilitate preclinical AAV gene therapy studies in canine models of DMD.
