366. Hitting Two Birds with One Stone: How Efficacious Pre-Clinical Gene Therapy Cures Canavan Disease and Sheds Light onto the Pathomechanism

Abstract

Almost 90 years ago, Canavan Disease (CD) was described for the first time. Since then, the scientific community has unsuccessfully sought to cure this devastating leukodystrophy and understand its pathomechanism. Early hope for gene therapy was fueled with the cloning of the disease causing gene, Aspartoacylase, in 1993. Unfortunately, the only clinical trial for CD gene therapy failed to show significant clinical improvements in Canavan patients. At that time, animal models for CD were just engineered and comprehensive pre-clinical evaluation of CD gene therapy was missing. Earlier, we reported that our 1st generation IV delivered pre-clinical gene therapy was able to rescue early lethality and partially restored motor function in a mouse model of CD. Now in its 3rd generation, our gene therapy cures the disease in Canavan mice by a single intravenous injection, shown by behavioral, cognitive, and neuropathology tests. Taking advantage of this complete reversal of the disease, we used whole brain neurometabolome profiling to closely monitor the molecular efficacy and mechanism(s) in curing Canavan disease in mouse. Hierarchical cluster analysis (HCA) shows complete restoration of the disease associated metabolic derangements, including the array of detected myelin lipids. In the next step, we hypothesized that the metabolic nature of Canavan Disease mandates the origin of its pathomechanism in the metabolic regulation. We identified a specific dysregulation in the energy metabolism in vitro and in vivo that suggests the self-digestion of myelin for energetic purposes, calling current hypotheses about the Canavan disease pathomechanism into question. Currently, we are intensifying our insight into this mechanism by mircoRNAome, transcriptome analyses, a series of in vitro cell culture models, as well as supplementary and alternative strategies for the treatment of Canavan Disease. In summary, our data demonstrates strong evidence that rAAV mediated pre-clinical gene therapy not only cures the Canavan phenotype but also corrects the extensive neurometabolome, which provides meticulous evidence for gene therapy's high efficacy. Furthermore, we revealed a new pathomechanism that supports a paradigm shift in our perception of the function of ASPA and NAA in Canavan disease and their potential implications in other CNS and metabolic disorders in general.