KRIT1 and cerebral cavernous malformation: To further test and validate the effects of mPR-specific PRG actions on the performance and maintenance of permeability of ECs, next, we plan to measure the stability of the BBB in WT and hemizygous Ccm1, Ccm2, and Ccm3 mutant mice strains (the same genetic composition as human familial CCM patients) in vivo.