MAPT and Alzheimer disease: Reduced brain glucose uptake impairs the attachment of O-linked N-acetylglucosamine, leading to the hyperphosphorylation of tau protein and subsequent formation of neurofibrillary tangles, which accumulate in the microvascular system of the brain in AD patients (Liu et al., 2004), and the integrity of the BBB is maintained when tau expression is suppressed (Zhang et al., 2007; Zhang et al., 2021).