Figure 2. rHSCs Located by N-Cad⁺ Endosteal Region in BM Niche.

(A) Representative whole-mount images of sternum, with bone (white by SHG) and megakaryocytes (MKs) (yellow, distinguished by size, morphology, and CD41 expression). Green and white arrowheads denote phenotypic rHSCs (Lin⁻CD48⁻CD41⁻CD150⁺CD49b⁻) and pHSCs (Lin⁻CD48⁻CD41⁻CD150⁺CD49b⁺).

(B) Representative images of rHSCs, pHSCs, and 5FU rHSCs (arrows). Scale bar, 10 μm.

(C–E) Relative distance between rHSCs, pHSCs, and 5FU rHSCs to BVs (C), bone (D), or N-cad⁺ cells (E) (n = 51 rHSCs, n = 144 pHSCs, n = 102 5FU rHSCs in distance quantification of HSCs from BVs and bone; n = 40 rHSCs, n = 50 pHSCs, n = 34 5FU rHSCs in distance quantification of HSCs from N-cad⁺ cells). n = 3 mice for each distance quantification dataset.

(F) Representative whole-mount images of N-cad-CreER^T; R26-ZsG mice induced by TMX for 24 h, co-stained with CD150, Lin, CD41, CD48, and CD49b as well as SHG signal (control and day 3 after 5FU).

(G) The rHSCs (arrows) localized near the N-cad⁺ bone surface after 5FU. Dashed-lined higher-power image (inset) shows one N-cad⁺ rHSC and one N-cad⁻ rHSC.

(H) Absolute numbers of AnnexinV⁺ SytoxG⁻ stromal cells in control and day 3 post-5FU (n = 3). *p < 0.05, **p < 0.01, ***p < 0.001. Error bars, SEM.