Figure 3. Sca-1⁺cKit⁺CD150⁺CD41⁻CD48⁻ Bone Marrow Cells Regulate Stromal Cell Fate In Vitro and In Vivo.

In (A) Sca-1⁺cKit⁺CD150⁺CD41⁻CD48⁻ bone marrow cells were isolated from hematopoetically ‘stressed’ and ‘non-stressed’ (puncture only) (−) animals at 48 hours and were directly added to pre-established murine BMSC derived from Runx2 knock-in animals. FACs profiles of the sorted HSCs are presented in Supplemental Figure 1. After 14 days, β-galactosidase activity was detected. The data are presented as mean ± s.d. for n=5 determinations in three independent investigations. In (B), vossicles derived from Runx2 knock-in animals or littermate controls were implanted into wild-type animals. Four vossicles (n=4) were in of each five mice (n=5). At one month, the vossicles were exposed and either injected with 500 Sca-1⁺cKit⁺CD150⁺CD41⁻CD48⁻ bone marrow cells isolated from hematopoetically stressed or ‘non-stressed’ animals, or sham injected with PBS. One week later, the vossicles were harvested and tissues stained for β-galactosidase by immunohistochemistry or for enzymatic activity (Bottom Left). Bar=50 microns. IgG control stained tissues are not presented but did not differ from sham injected knock-in tissues. Quantification of the data is presented in the Bottom Right panel. The data demonstrate that Sca-1⁺cKit⁺CD150⁺CD41⁻CD48⁻ induce Runx2 expression in vitro and in vivo.