Gene supplementation in Vanishing White Matter mice ameliorates the disease

Vanishing White Matter is a leukodystrophy associated with neurological decline, including motor deficits, and premature death. It is caused by mutations in the genes encoding the subunits of eukaryotic Translation Initiation Factor 2B (eIF2B), leading to constitutive activation of the Integrated Stress Response, especially in astrocytes. Brain pathology shows immature and dysfunctional glia in the central nervous system. No curative treatment options are currently available for Vanishing White Matter patients. To investigate a gene therapy approach, we supplemented Eif2b5-mutant Vanishing White Matter mice with the wild-type Eif2b5 gene sequence. We tested lentiviral vectors with different promoters to target astrocytes or cells with heightened Integrated Stress Response activity. The regenerative effects of intracerebroventricular injection in neonates were tested in adulthood. Motor skills and pathology in the central nervous system were improved when wild-type Eif2b5 delivery was targeted towards astrocytes. No negative side-effects of overexpression were observed in any of the groups. In conclusion, gene supplementation in astrocytes is effective in alleviating disease severity, showing promise for gene therapy for Vanishing White Matter patients.