Fig. 1

Expression of cell-cell contact proteins and membrane transporters in the mouse choroid plexus primary culture. Immunofluorescence labeling of mouse choroid plexus primary culture for the tight junction proteins Claudin 2 (A) and Occludin (B). Arrows indicate intercellular junctions expressing both proteins. Nuclei (blue) are stained with Topro. C) Immunofluorescence labeling of cultures for the Na⁺ dependent Cl⁻/HCO₃⁻ exchanger, Ncbe (green), in the basolateral membrane. The arrows indicate examples of the basolateral labyrinths; characteristic of the CP. Ncbe-specific labelling is also seen in intracellular vesicles (arrow heads). Cell nuclei are stained with Topro nuclear stain (blue). A z-stack through the cells confirms basolateral Ncbe (green) expression (D). Immunofluorescense labelling confirms expression of NKCC1 (green, E) and Na, K ATPase (Red, F) in the membrane of the CP cells. Overlaying the images, the yellow color confirms colocalization of the two luminal transporters (G). Arrows indicate examples of the membrane specific staining (E and F) as well as subcellular co-localization in the overlayed image (G). Z-stacks confirm correct polarization of the luminal Na, K ATPase (red, H) and NKCC1 (blue color at arrow heads, I) when co-labelled with Ncbe (green). (J) Trans-epithelial electrical resistance measured at 3, 5, 7, 8, 9 and 10 days after seeding. TEER values represent mean ± SEM. **indicates p < 0.01 and **** indicates p < 0.0001