Spanish researchers generated different isogenic mouse muscle cell lines that mimic severe Pompe disease and validated their applicability as preclinical models of the disease. These cell lines can be used to screen potential gene therapy strategies for the disease while reducing the number of animals used in research.

The generated cell lines lack the acid alpha-glucosidase (GAA) gene, therefore resembling severe mutations found in patients with Pompe disease. The researchers reported that the cell lines all lacked GAA enzyme activity, had increased autophagy and glycogen content, and reduced surface cation-independent mannose 6-phosphate receptors (CI-MPRs), validating them as Pompe disease models.

The researchers then conducted rescue experiments. First, they generated chimeric mouse GAA protein, and then, using lentiviral vectors, they introduced these chimeric proteins back into the cells. This showed that the IFG chimera, which harbors the interferon β-1 leader peptide to improve secretion, was the best candidate for restoring GAA enzyme activity and normalizing autophagic markers and surface CI-MPRs. 


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Finally, the researchers conducted animal experiments and showed that when they administered the chimeras to live animals using liver-directed adeno-associated virus (AAV) vectors, IFG once again produced the best results in achieving cross-correction in the heart tissue of the animals.

Read more about gene therapy for Pompe disease

“Our isogenic murine GAA-[knock-out] models, together with the human cell lines, are useful tools for the analysis of [lentiviruses] expressing different GAA chimeras,” the researchers concluded. They added that although IFG could be a potential candidate for gene therapy for Pompe disease, they “consider that it requires further refinement before moving forward to [gene therapy] applications.”

Pompe disease is caused by a mutation in the GAA gene, which leads to GAA deficiency. The role of the GAA enzyme is to break down glycogen; when it does not function properly, glycogen accumulates inside cells, causing damage. 

The study is published in the International Journal of Molecular Sciences.

Reference

Aguilar-González A, González-Correa JE, Barriocanal-Casado E, et al. Isogenic GAA-KO murine muscle cell lines mimicking severe Pompe mutations as preclinical models for the screening of potential gene therapy strategies. Int J Mol Sci. 2022;23(11):6298. doi:10.3390/ijms23116298