Pharmacological modulation of glutamatergic and neuroinflammatory pathways in a Lafora disease mouse model

Abstract

Lafora disease (LD) is a fatal rare neurodegenerative disorder that affects young adolescents and has no treatment yet. The hallmark of LD is the presence of polyglucosan inclusions (PGs), called Lafora bodies (LBs), in the brain and peripheral tissues. LD is caused by mutations in either EPM2A or EPM2B genes, which respectively encode laforin, a glucan phosphatase, and malin, an E3-ubiquitin ligase, with identical clinical presentation. LD knockout mouse models (Epm2a-/- and Epm2b-/-) recapitulate PGs body accumulation, as in the human pathology, and display alterations in glutamatergic transmission and neuroinflammatory pathways in the brain. In this work, we show the results of four pre-clinical trials based on the modulation of glutamatergic transmission (riluzole and memantine) and anti-neuroinflammatory interventions (resveratrol and minocycline) as therapeutical strategies in an Epm2b-/- mouse model. Drugs were administered in mice from 3 to 5 months of age, corresponding early stage of the disease, and we evaluated the beneficial effect of the drugs by in vivo behavioral phenotyping and ex vivo histopathological brain analyses. The behavioral assessment was based on a battery of anxiety, cognitive, and neurodegenerative tests and the histopathological analyses included a panel of markers regarding PGs accumulation, astrogliosis, and microgliosis. Overall, the outcome of ameliorating the excessive glutamatergic neurotransmission present in Epm2b-/- mice by memantine displayed therapeutic effectiveness at the behavioral levels. Modulation of neuroinflammation by resveratrol and minocycline also showed beneficial effects at the behavioral level. Therefore, our study suggests that both therapeutical strategies could be beneficial for the treatment of LD patients.