Importantly, we demonstrate that TGF-β inhibition in APOE4 human brain tissue reverses the pericyte-to-myofibroblast transition and reduces cerebrovascular fibrosis and amyloid accumulation, thus providing a direct mechanistic link between APOE4, TGF-β, vascular fibrosis, and AD pathogenesis. Here, TGFB1 is linked to Alzheimer disease.