Figure 2.

Expression of MCT8 and OATP1C1 in the cerebral barriers of the human and macaque motor cortex. Representative brightfield (A,E,I,M) and fluorescence confocal microscope (B–D,F–H,J–L,N–T) photomicrographs showing immunostaining for MCT8 (A–H,Q–T) and OATP1C1 (I–P) in blood vessels of human and macaque motor cortex. (A,E) show strong MCT8 staining in the endothelial layer of small vessels and capillaries (white arrowheads) in humans and macaques, respectively. (B–D,F–H) show colocalization of MCT8 (green) with the endothelial markers UEA-I (red) and ENG (red). (I,M) show weak OATP1C1 staining in small vessels (white arrowheads) and venules (black arrowheads). The red arrowhead in M points to a glial cell positive for OATP1C1 with processes surrounding the capillary. (J–L,N–P) show colocalization of OATP1C1 (green) with UEA-I (red) and endoglin (red) in a few blood vessels of the human and macaque motor cortex, respectively. White arrowheads point to vessels. In both human and macaque brain tissues, MCT8-immunopositive capillaries are much more abundant than OATP1C1-immunopositive capillaries, which can only be seen occasionally. Moreover, (Q–T) show MCT8-expressing pericytes (white arrowheads) in the human motor cortex that in addition to express MCT8 (green), also show the pericyte biomarker PDGFR-β (pink), but not the endothelial marker UEA-I (red). Counterstaining with DAPI (blue) shows nuclei of all cells. ENG: endoglin, UEA-I: Ulex Europaeus Agglutinin-I. PDGFR-β: platelet-derived growth factor receptor beta. Scale bar = 100 μm (A,E,I,M), 25 μm (B–D), 50 μm (J–L), 120 μm (F–H,N–P), and 12 μm (Q–T).