Targeting Pathogenic Lafora Bodies in Lafora Disease Using an Antibody-Enzyme Fusion

Abstract

Lafora disease (LD) is a fatal childhood epilepsy caused by recessive mutations in either the EPM2A or EPM2B gene. A hallmark of LD is the intracellular accumulation of insoluble polysaccharide deposits known as Lafora bodies (LBs) in the brain and other tissues. In LD mouse models, genetic reduction of glycogen synthesis eliminates LB formation and rescues the neurological phenotype. Therefore, LBs have become a therapeutic target for ameliorating LD. Herein, we demonstrate that human pancreatic α-amylase degrades LBs. We fused this amylase to a cell-penetrating antibody fragment, and this antibody-enzyme fusion (VAL-0417) degrades LBs in vitro and dramatically reduces LB loads in vivo in Epm2a^-/- mice. Using metabolomics and multivariate analysis, we demonstrate that VAL-0417 treatment of Epm2a^-/- mice reverses the metabolic phenotype to a wild-type profile. VAL-0417 is a promising drug for the treatment of LD and a putative precision therapy platform for intractable epilepsy.

Keywords: Lafora bodies; Lafora disease; amylase; antibody-based drug; antibody-enzyme fusion; enzyme therapy; epilepsy; glycogen; glycogen storage disease; metabolomics.