Pharmacological competitive inhibition of heparan sulfate modulates Vcam1-dependent adhesion. (A-B) Vcam1 inhibition abrogates heparin-induced mobilization. (A) PB circulating progenitor cells measured by CFU assay in animals receiving vehicle, AMD3100, or Vcam1 neutralizing antibody alone or in combination with heparin. Gray shadowed area is intended to highlight the fact that coadministration of heparin enhances AMD3100-induced mobilization. (B) Representative image of the CFU assay quantified in A. (C) Relative PB reconstitution, 16 weeks after transplantation, of recipient CD45.1 mice transfused with PB from Ext1 control or mutant mice (CD45.2) receiving G-CSF alone or in combination with AMD3100. Recipient mice were lethally irradiated and received CD45.1 cells for radioprotection. Data are representative of at least 2 independent experiments; n = 5 to 8 mice per genotype per experiment. In mobilization experiments, PB was collected from at least 5 mice per experimental group. Data are represented as mean ± SD or median ± interquartile range. *P < .05; **P < .01; ***P < .001.