Fluorescence immunohistochemical staining of hypoxic peri-arteriolar HSCs
in human bone marrow (A-C, F, G) and hypoxic peri-arteriolar GSCs in
human glioblastoma (D, E, H, I). Yellow rectangle in A is enlarged in B
and C. CD133-expressing HSCs are localized around a SMA-positive
arteriole (a) adjacent to bone (b) in bone marrow (B, yellow arrows).
CD133 is also expressed in endothelial cells and smooth muscle cells of
the arteriolar wall (A, B). CD150-positive HSCs are localized around the
arteriole adjacent to bone in bone marrow (C, yellow arrows). CD150
expression is detected in endothelial cells and smooth muscle cells in
the wall of the arteriole (C). SMA is expressed in smooth muscle cells
in the tunica media (tm) of the arteriolar wall in glioblastoma (D).
GSCs express CD133 and SOX2 and are localized adjacent to the tunica
adventitia (ta) of the arteriole (a) in glioblastoma (E, yellow arrows).
HIF-1α is abundantly expressed in the arteriolar wall in bone marrow
(F). HIF-2α is highly expressed in HSCs in a HSC niche (F). A subset of
HSCs express both HIF-1α and HIF-2α (F, yellow arrows). VEGF is
abundantly expressed throughout bone marrow (G). HIF-1α is abundantly
expressed in the arteriolar wall in glioblastoma (H). HIF-2α is highly
expressed in GSCs (H, yellow arrows). VEGF is abundantly expressed
throughout glioblastoma (I). Nuclear counterstaining with DAPI (blue).
Scale bar = 100 µm. Abbreviations: HSC, hematopoietic stem cell; GSC,
glioblastoma stem cell; SMA, smooth muscle actin; tm, tunica media;
SOX2, sex determining region Y-box 2; ta, tunica adventitia; DAPI,
4’,6-diamidino-2-phenylindole; HIF, hypoxia-induced factor; VEGF,
vascular endothelial growth factor.