AAV-GAA Gene Therapy Clears Long Chain Length Neuronal Glycogen in a Pompe Disease Rat Model

Abstract

Pompe disease is due to mutations in the acid a-glucosidase (GAA) gene. GAA protein degrades lysosomal glycogen and dysfunctional or absent protein leads to cellular glycogen accumulation. In recent years, it has become clear that glycogen accumulation in the central nervous system (CNS) needs to be targeted in Pompe disease. However, the standard of care — intravenous enzyme replacement therapy using recombinant GAA does not effectively target the CNS. Here, we investigated the ability of neonatal AAV-GAA therapy to clear neuronal glycogen in the Pompe ( Gaa−/−) rat. On post-natal day one, male Gaa−/− rats received an administration of AAV9-DES-hGAA (1x1014 vector genomes/kg) via the temporal vein injection or sham injection (1xPBS). Rats were euthanized at age 9 months, and spinal cords and the diaphragm muscle were harvested and glycogen biochemistry was evaluated by matrix-assisted laser desorption/ionization mass spectrometry glycogen imaging (MALDI) and immunohistochemistry (GAA antibody). MALDI imaging reveal significant reduction in glycogen accumulation in the cervical spinal cord, and AAV9-DES-hGAA selectively targeting longer glucose chains within glycogen. Immunohistochemistry verified GAA expression in spinal cord neurons of rats treated with AAV-GAA. In the diaphragm muscle, MALDI revealed that the expected increase glycogen in the untreated Pompe diaphragm was associated with a decrease in n-linked glycans, a potential biomarker of the disease. Strikingly, glycogen content and glycans in the AAV-GAA treated diaphragm were indistinguishable from wild type. We conclude the neonatal gene therapy with AAV9-DES-hGAA can drive functionally relevant GAA expression in the adult rat CNS, and also effectively targets the diaphragm. R01HD052682 (DDF and BJB), R01AG066653 (RCS), R01CA266004 (RCS), R01AG078702 (RCS), RM1NS133593 (RCS), R35NS116824 (MSG). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.