Heparan sulfate modulates HSCs microanatomical positioning. (A-C) Relative positioning of HSCs in the BM cavity. (A) Control and mutant mice were bred into a strain expressing GFP under the Col2.3 promoter labeling osteoblastic cells. (B) Representative pictures of the BM cavity of control and mutant mice injected with equal numbers of DiD-labeled HSCs (red); blue, second-harmonic generation signal (bone); green, Col2.3GFP (osteoblasts). Scale bars, 100 μm. (C) Distances of LKS CD48⁻CD150⁺ HSCs 24 hours after transplantation, from Col2.3GFP cells (left) and endosteal surface (right) in micrometers. Data represent 2 independent experiments; n = 2 mice per genotype per experiment. Data are represented as mean ± SD. *P < .05; **P < .01; ***P < .001.