A functional mini-GDE transgene corrects impairment in models of glycogen storage disease type III
Antoine Gardin, Jérémy Rouillon, Valle Montalvo-Romeral, Lucille Rossiaud, Patrice Vidal, Romain Launay, Mallaury Vie, Youssef Krimi Benchekroun, Jérémie Cosette, Bérangère Bertin, Tiziana La Bella, Guillaume Dubreuil, Justine Nozi, Louisa Jauze, Romain Fragnoud, Nathalie Daniele, Laetitia Van Wittenberghe, Jérémy Esque, Isabelle André, Xavier Nissan, Lucile Hoch, Giuseppe Ronzitti
Antoine Gardin, Jérémy Rouillon, Valle Montalvo-Romeral, Lucille Rossiaud, Patrice Vidal, Romain Launay, Mallaury Vie, Youssef Krimi Benchekroun, Jérémie Cosette, Bérangère Bertin, Tiziana La Bella, Guillaume Dubreuil, Justine Nozi, Louisa Jauze, Romain Fragnoud, Nathalie Daniele, Laetitia Van Wittenberghe, Jérémy Esque, Isabelle André, Xavier Nissan, Lucile Hoch, Giuseppe Ronzitti
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Research Article Metabolism

A functional mini-GDE transgene corrects impairment in models of glycogen storage disease type III

Abstract

Glycogen storage disease type III (GSDIII) is a rare inborn error of metabolism affecting liver, skeletal muscle, and heart due to mutations of the AGL gene encoding for the glycogen debranching enzyme (GDE). No curative treatment exists for GSDIII. The 4.6 kb GDE cDNA represents the major technical challenge toward the development of a single recombinant adeno-associated virus–derived (rAAV-derived) vector gene therapy strategy. Using information on GDE structure and molecular modeling, we generated multiple truncated GDEs. Among them, an N-terminal–truncated mutant, ΔNter2-GDE, had a similar efficacy in vivo compared with the full-size enzyme. A rAAV vector expressing ΔNter2-GDE allowed significant glycogen reduction in heart and muscle of Agl–/– mice 3 months after i.v. injection, as well as normalization of histology features and restoration of muscle strength. Similarly, glycogen accumulation and histological features were corrected in a recently generated Agl–/– rat model. Finally, transduction with rAAV vectors encoding ΔNter2-GDE corrected glycogen accumulation in an in vitro human skeletal muscle cellular model of GSDIII. In conclusion, our results demonstrated the ability of a single rAAV vector expressing a functional mini-GDE transgene to correct the muscle and heart phenotype in multiple models of GSDIII, supporting its clinical translation to patients with GSDIII.

Authors

Antoine Gardin, Jérémy Rouillon, Valle Montalvo-Romeral, Lucille Rossiaud, Patrice Vidal, Romain Launay, Mallaury Vie, Youssef Krimi Benchekroun, Jérémie Cosette, Bérangère Bertin, Tiziana La Bella, Guillaume Dubreuil, Justine Nozi, Louisa Jauze, Romain Fragnoud, Nathalie Daniele, Laetitia Van Wittenberghe, Jérémy Esque, Isabelle André, Xavier Nissan, Lucile Hoch, Giuseppe Ronzitti

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Figure 1

Generation of truncated GDE polypeptides in the C domain.

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Generation of truncated GDE polypeptides in the C domain. (A) Schematic ...
(A) Schematic representation of the human GDE cDNA, depicting the different functional domains and the 2 catalytic sites (28), as well as the position of missense mutations reported in patients with GSDIII (2, 5, 6, 28, 31–38). (B) 4–5 month-old male Agl–/– mice were injected in the tail vein with an rAAV-MT vector encoding ΔC1 to ΔC4 GDE mutants, at the dose of 1 × 1014 vg/kg. PBS-injected Agl+/+ or Agl–/– mice were used as controls. (C) Western blot analysis of GDE and vinculin expression in heart and triceps 3 months after vector injection. (D) Glycogen content measured in heart and triceps 3 months after vector injection. (E) Wire-hang test expressed as the number of falls per minute, performed 3 months after vector injection. Statistical analyses were performed by 1-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001 versus PBS-injected Agl–/– mice; #P < 0.05, ##P < 0.01, ###P < 0.001 versus PBS-injected Agl+/+ mice; n = 4–5 mice per group. All data are shown as mean ±SEM.