FIG. 6.

Treatment of CD36⁺/Epo⁺ EPCs with the Jak2-specific inhibitor AG490 leads to a dose-dependent decrease in phosphorylated Jak2 and EpoR but does not affect the cell cycle. At day 7 in culture, CD36⁺/Epo⁺ EPCs were treated with AG490 at the indicated concentrations or with DMSO (0.5%; control). They were infected with B19V 24 h later (day 8). (A) Protein phosphorylation was assessed by Western blotting of a subpopulation of the cells using the indicated antibodies (left), and the bands were quantitated relative to their counterparts in DMSO (right). (B) Cell viability (to assess cytotoxicity of treatment), as evaluated using the CellTiter-Glo kit. The luminescence readings shown are normalized against values for the cell control group (no treatment). (C) Cell viability (to assess cytotoxicity of treatment), as evaluated by annexin V/PI staining (cell death) and DAPI staining (indicator of cell cycle stage). For annexin V/PI staining, the numbers shown in the lower left quadrants represent the percentages of live cells, and the numbers in each upper and lower right quadrants represent the percentages of later/early apoptotic cells. In the case of DAPI staining, the numbers represent the percentages of cells in each phase of the cell cycle (G₀/G₁, S, and G₂/M).