Expression and function of four AAV-based constructs for dystrophin restoration in the mdx mouse model of Duchenne muscular dystrophy

Rachael A Potter; Danielle A Griffin; Kristin N Heller; Jerry R Mendell; Louise R Rodino-Klapac

doi:10.1242/bio.059797

Expression and function of four AAV-based constructs for dystrophin restoration in the mdx mouse model of Duchenne muscular dystrophy

Biol Open. 2023 Sep 15;12(9):bio059797. doi: 10.1242/bio.059797. Epub 2023 Sep 15.

Authors

Rachael A Potter^{1

2}, Danielle A Griffin^{1

2}, Kristin N Heller¹, Jerry R Mendell^{1

3}, Louise R Rodino-Klapac^{1

2

3}

Affiliations

¹ Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.
² Sarepta Therapeutics, Inc., Cambridge, MA 02142, USA.
³ Department of Pediatrics and Neurology, The Ohio State University, Columbus, OH 43210, USA.

Abstract

Robust expression of shortened, functional dystrophin provided impetus to develop adeno-associated virus (AAV)-based constructs for clinical application. Because several cassettes are being tested in clinical trials, this study compared the efficacies of four shortened dystrophin-promoter combinations with implications for outcomes in clinical trials: MHCK7 or MCK promoter with a shortened dystrophin transgene containing the N-terminus and spectrin repeats R1, R2, R3 and R24 (rAAVrh74.MHCK7.micro-dystrophin and rAAVrh74.MCK.micro-dystrophin, respectively); shortened dystrophin construct containing the neuronal nitric oxide (nNOS) binding site (rAAVrh74.MHCK7.DV.mini-dystrophin); and shortened dystrophin containing the C-terminus (rAAVrh74.MHCK7.micro-dystrophin.Cterm). Functional and histological benefit were examined at 4 weeks following intramuscular delivery in mdx mice. rAAVrh74.MHCK7.micro-dystrophin provided the most robust transgene expression and significantly increased specific force output in the tibialis anterior muscle. Muscle environment was normalized (i.e. reductions in central nucleation), indicating functional and histological advantages of rAAVrh74.MHCK7.micro-dystrophin. Thus, promoter choice and transgene design are critical for optimal dystrophin expression/distribution for maximal functional improvement.

Keywords: Mdx mouse model; Adeno-associated virus; Duchenne muscular dystrophy; Dystrophin; Gene therapy; Micro-dystrophin.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Actin Cytoskeleton
Animals
Dependovirus / genetics
Disease Models, Animal
Dystrophin* / genetics
Mice
Mice, Inbred mdx
Muscular Dystrophy, Duchenne* / genetics
Muscular Dystrophy, Duchenne* / therapy

Substances

Dystrophin