A team from Inserm and Université de Bordeaux developed mitoDREADD-Gs, a mitochondria-targeted designer receptor that, when activated, enhances mitochondrial energy functions and reverses cognitive impairment in mouse models of Alzheimer’s disease and frontotemporal dementia. This study provides causal evidence linking mitochondrial dysfunction to neurodegeneration symptoms and opens avenues for therapies aimed at restoring mitochondrial activity to preserve brain function.