Molecular profiling of seizures to provide comprehensive, durable, and targeted treatment for inherited white matter disorders

PROJECT ABSTRACT/SUMMARY Leukodystrophies are genetic neurodegenerative diseases that affect the white matter within the central nervous system (CNS) and commonly manifest during childhood. They have a range of cellular etiologies, with some resulting from astrocytic dysfunction; two of these include Vanishing White Matter Disease (VWM) and Alexander’s Disease (AxD). While both diseases lead to demyelination, motor abnormalities, intellectual disability, seizures, and pre- mature death, AxD can be inherited or sporadic, and is caused by autosomal dominant, toxic gain-of-function mutations in glial fibrillary acidic protein (GFAP). VWM, however, is caused by loss-of-function mutations in the subunits [1-5] of eukaryotic initiation factor 2B (eIF2B), most commonly in EIF2B5. Both have no treatments. Due to VWM’s monogenic and recessive nature, it is a good candidate for adeno-associated virus (AAV)- mediated gene supplementation therapy. Therefore, my dissertation has focused on characterizing and treating the severe Eif2b5I98M murine model with an astrocyte-targeted AAV9-EIF2B5 gene therapy. We designed constructs to drive astrocyte-specific or ubiquitous therapeutic EIF2B5 transgene expression. Ongoing efficacy studies indicate that these vectors partially rescue body weight and motor function, and significantly extend survival of Eif2b5I98M mice; however, these animals are now experiencing severe and life-limiting seizures. Preliminary data in treated VWM mice shows we were able to restore EIF2B5 expression, however analysis of the integrated stress response (ISR)—a pathway that is mediated by eIF2B and rescues homeostasis after cell stress—remained dysregulated. Therefore, we hypothesize that uncorrected molecular pathways (ISR) in primary and secondary cell types are leading to incomplete rescue. We propose that synergistic combination utilizing the clinically relevant ISR modulator, Integrated Stress Response Inhibitor (ISRIB), and our gene therapy will provide a targeted and more comprehensive correction of disease. ISRIB has been shown to lessen VWM pathologies by stabilizing the mutated eIF2B complex and is now in a clinical trial for VWM [NCT05757141]. Herein, in the F99 phase (Aim 1), I propose to learn and utilize cutting edge approaches including state-of-the-art sequencing and multiomic analyses to elucidate the molecular profile of incomplete treatment, to then provide a more durable, comprehensive, and targeted therapeutic approach for VWM. To continue my academic career and to strengthen my training in neuroscience-focused gene therapy, in the K00 phase (Aim 2) I propose to diversify my scientific repertoire with novel therapeutic approaches that are applicable to more complex white matter disorders—such as toxic gain-of-function, AxD—as well as advance my training in in vitro and in vivo model characterization and pre-clinical efficacy testing through the implementation and testing of AAV-mediated astrocyte-targeted gene knockdown of toxic GFAP. The goal is to provide a durable, safe, and efficacious treatment for AxD.