Cytoskeleton architecture of HSPCs in adhesive and nonadhesive microwells. (A) Inverted images of selected Z stacks of two representative HSPC polarized on osteoblasts. Upper panel: Microtubules appear in black and the centrosome in red. Lower panel: Nucleus (DNA staining) appears in black. (B) Inverted images of selected Z stacks of actin organization in representative HSPCs polarized upon contact with osteoblast. The point of contact is highlighted with a black arrow. (C) Cytoskeleton architecture of HSPCs in a nonadhesive microwell. Selected Z stack (z = 0–10 µm) of a representative HSPC cultured in a PAA microwell (nonadhesive). Microtubules appear in green, centrosome in white, and DNA in blue. The centrosome was tightly associated with the nucleus, and not proximal to the glass bottom. Scale bar = 5 µm. (D) Inverted images of representative HSPCs cultured in PAA microwells. Upper panel: Microtubules appear in black and the centrosome in red. Lower panel: Corresponding image of the nucleus. Scale bar = 5 µm.