Extended Data Figure 2. Vascular lesions due to CCM LOF and/or PIK3CA GOF arise in veins of the white matter.

a, Schematic of neonatal endothelial induction of Krit1 deletion and/or PIK3CA^H1047R expression. b & c, Hematoxylin-Eosin (H-E) staining of saggital hindbrain sections from P6 control, Pik3ca^iBECGOF, Krit1^iBECKO;Pik3ca^iBECGOF (b and b’) and Krit1^iBECKO (c and c’) animals with a resistant (Res) or susceptible (Susc) microbiome. b’and c’ samples were obtained from animals distinct from those in b and c. Note that lesions form in the white matter with both CCM loss of function and PIK3CA gain of function. Boxes in upper images denote area of magnified image immediately below. Dotted lines outline the white matter of the cerebellum. Arrows indicate lesions in white matter veins and venules. H-E images representative of 6 tissue sections from n=4 animals/genotype. wm, white matter. Scale bars, 0.1mm.