EIF2B2 mutations in vanishing white matter disease hypersuppress translation and delay recovery during the integrated stress response.

Mutations in eIF2B genes cause vanishing white matter disease (VWMD), a fatal leukodystrophy that can manifest following physical trauma or illness, conditions that activate the integrated stress response (ISR). EIF2B is the guanine exchange factor for eIF2, facilitating ternary complex formation and translation initiation. During the ISR, eIF2α is phosphorylated and inhibits eIF2B, causing global translation suppression and stress-induced gene translation, allowing stress adaptation and recovery. We demonstrate that VWMD patient cells hypersuppress translation during the ISR caused by acute ER stress, delaying stress-induced gene expression and interrupting a negative feedback loop that allows translational recovery by GADD34-mediated dephosphorylation of phospho-eIF2α. Thus, cells from VWMD patients undergo a prolonged state of translational hyperrepression and fail to recover from stress. We demonstrate that small molecules targeting eIF2B or the eIF2α kinase PERK rescue translation defects in patient cells. Therefore, defects in the ISR could contribute to white matter loss in VWMD.