Efficacy and muscle safety assessment of fukutin-related protein gene therapy

Halli Benasutti; Joseph W Maricelli; Jane Seto; John Hall; Christine Halbert; Jacqueline Wicki; Lydia Heusgen; Nicholas Purvis; Michael Regnier; David C Lin; Buel D Rodgers; Jeffrey S Chamberlain

doi:10.1016/j.omtm.2023.05.022

Efficacy and muscle safety assessment of fukutin-related protein gene therapy

Mol Ther Methods Clin Dev. 2023 Jun 4:30:65-80. doi: 10.1016/j.omtm.2023.05.022. eCollection 2023 Sep 14.

Authors

Halli Benasutti^{1

2}, Joseph W Maricelli^{3

4}, Jane Seto^{2

5}, John Hall², Christine Halbert^{2

5}, Jacqueline Wicki², Lydia Heusgen², Nicholas Purvis², Michael Regnier⁶, David C Lin⁷, Buel D Rodgers^{3

4}, Jeffrey S Chamberlain^{1

2

5

8}

Affiliations

¹ Department of Biochemistry, University of Washington School of Medicine, Seattle, WA, USA.
² Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA.
³ School of Molecular Biosciences, Washington State University College of Veterinary Medicine, Pullman, WA 99164, USA.
⁴ Washington Center for Muscle Biology, Washington State University, Pullman, WA 99164, USA.
⁵ Sen. Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA, USA.
⁶ Department of Bioengineering, University of Washington School of Medicine, Seattle, WA, USA.
⁷ Department of Integrative Physiology and Neuroscience and the Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164, USA.
⁸ Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA.

Abstract

Limb-girdle muscular dystrophy type R9 (LGMDR9) is a muscle-wasting disease that begins in the hip and shoulder regions of the body. This disease is caused by mutations in fukutin-related protein (FKRP), a glycosyltransferase critical for maintaining muscle cell integrity. Here we investigated potential gene therapies for LGMDR9 containing an FKRP expression construct with untranslated region (UTR) modifications. Initial studies treated an aged dystrophic mouse model (FKRP^P448L) with adeno-associated virus vector serotype 6 (AAV6). Grip strength improved in a dose- and time-dependent manner, injected mice exhibited fewer central nuclei and serum creatine kinase levels were 3- and 5-fold lower compared to those in non-injected FKRP^P448L mice. Treatment also partially stabilized the respiratory pattern during exercise and improved treadmill running, partially protecting muscle from exercise-induced damage. Western blotting of C2C12 myotubes using a novel rabbit antibody confirmed heightened translation with the UTR modifications. We further explored the question of FKRP toxicity in wild-type mice using high doses of two additional muscle-tropic capsids: AAV9 and AAVMYO1. No toxic effects were detected with either therapeutic agent. These data further support the feasibility of gene therapy to treat LGMDR9.

Keywords: Ck8; FKRP; adeno-associated viral vector (AAV); fukutin-related protein; gene therapy; limb-girdle muscular dystrophy type R9 (LGMDR9); muscular dystrophy; physiology.

Abstract

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