Fig. 2

Oligodendrocytes are in direct contact with the vascular basement membrane

(A) Confocal images of a vOL (cyan, arrowhead) on a blood vessel (red). The location was marked with 2-photon branding and the created laser mark is well visible using green excitation light (see arrow). (B) Single-plane block-face image of the same oligodendrocyte as in (A) showing the direct contact between the cell body (light cyan,) and the basement membrane (dark red). Arrowheads denote the length of the contact and the boxed area is displayed at higher magnification. (C) 3D rendering of the reconstructed vOL in A and B, the basement membrane and the blood vessel lumen. The oligodendrocyte cell body closely follows the blood vessel shape. (D) Two example EM images showing traced processes from the cell body (light cyan) ending in compact myelin (green). (E) Example 3D volume image of a vOL (blue) and vasculature (red) obtained from the Microns dataset. (F) Example EM false colored images of contact sites between the vasculature and vOLs (cyan) from the MICrONS dataset. Arrows point to the contact site. (G) Left: annotated example EM image of astrocyte endfeet (A), oligodendrocyte (OL) and a presumed endothelial cell of the vasculature (Endo). Right: 3D reconstructions of the microns dataset show the arrangement of the astrocyte endfeet on the vasculature (top) and oligodendrocyte (bottom). (H) Single plane confocal images showing aquaporin-4 labeling of the vasculature (gray) and oligodendrocyte cell body (cyan) labeling in a Cnp-mGFP mouse. Bottom: Fluorescence intensity plots for both channels, showing a reduction of Aquaporin-4 labeling intensity at the contact site. (I) Quantification of the aquaporin-4 fluorescence and comparison between contact and non-contact sites show a reduced intensity of aquaporin-4 signal at the contact sites (Paired t-test, p = 0.0001, n = 13 cells from 4 animals).