APP and Alzheimer disease: Additionally, it has been shown that inhibition of RhoA‐GTP attenuates the BBB permeability (van Nieuw Amerongen & van Hinsbergh, 2007) and RhoA is activated in the cerebral cortex of the Tg2576 mice model of AD that overexpresses a mutant form of APP (KM670/671NL) (Petratos et al., 2008).