Figure 6.

G-CSFRIV–mediated hyperproliferative response is compromised in the presence of a Stat5 inhibitor or shmiR-155. (A) CD34⁺ HSPCs were transduced with a lentiviral vector containing either G-CSFRI or G-CSFRIV encoding sequences. Cells (1 × 10⁵) were labeled with CPD eFluor 670 and stimulated with 100 ng/mL G-CSF together with DMSO as control or with a Stat5 inhibitor (100 μmol/L) for 3 d followed by FACS analysis. GFP expression was used to distinguish G-CSFR overexpressing and nontransduced cells. Graph displays MFI of CPD eFluor 670 on G-CSFRI⁺ and G-CSFRIV⁺ HSPCs. Data are mean ± SD of eight independent experiments. (B) CD34⁺ HSPCs were transduced with a G-CSFRI or G-CSFRIV encoding lentiviral vector together with shmiR-155 or shNC. GFP and DsRed were used to distinguish transduced and nontransduced cells. Cells (1 × 10⁵) were labeled with CPD eFluor 670 and stimulated with 100 ng/mL G-CSF for 3 d followed by FACS analysis. Graph displays MFI of CPD eFluor 670 on G-CSFRI⁺ shNC, G-CSFRI⁺ shmiR-155, G-CSFRIV⁺ shNC and G-CSFRIV⁺ shmiR-155 cells. The data shown are mean ± SD of four independent experiments. Statistically significant differences were calculated using a two-tailed Student t test and are shown with asterisks (*p < 0.05, **p < 0.01 and ***p < 0.001).