Neuron-Specific AAV-Mediated WWOX Gene Therapy Rescues Mortality and Seizure Phenotypes in WOREE Syndrome Models

Gene products of common fragile sites (CFSs), such as WW domain-containing
oxidoreductase (WWOX), are well-documented in cancer and increasingly linked to
neurological diseases, including epilepsy, multiple sclerosis, and Alzheimer’s
disease. Pathogenic bi-allelic germline WWOX variants are associated with rare
autosomal recessive disorders, including spinocerebellar ataxia 12 (SCAR12) and
WWOX-related epileptic encephalopathy (WOREE syndrome). These disorders are
characterized by severe epilepsy, profound developmental delay, and early lethality.
The underlying mechanisms of WWOX actions in these disorders are poorly
understood. Using genetically engineered mouse models, we demonstrated that
neuronal Wwox ablation leads to brain hyperexcitability, intractable epilepsy, ataxia,
profound hypomyelination, and postnatal lethality. Based on this knowledge, we next
aimed to check whether neuronal WWOX delivery could rescue the phenotypes of
Wwox null mice. To this end, we developed and tested an adeno-associated viral
vector (AAV9) harboring human WWOX cDNA under the neuronal Synapsin I
promoter (AAV9-SynI-WWOX). Testing the efficacy of optimal AAV-SynI-WWOX
delivery in Wwox-null mice demonstrated that specific neuronal restoration of
WWOX expression rescued brain hyperexcitability and seizures, hypoglycemia,
myelination deficits, and the premature lethality and behavioral deficits of Wwox-null
mice. Refinements to the vector design, including removal of the WPRE element to
mitigate overexpression risks, further enhanced safety and efficacy. These findings
underscore the therapeutic potential of WWOX gene therapy, paving the way for
transformative treatments for devastating WWOX-associated disorders such as
WOREE syndrome and SCAR12.