Inhibition of expression of differentiation markers hemoglobin and glycophorin A and impaired disappearance of CD34 in erythroid cells cocultivated with HZ or treated with HNE. (A-C) Erythroid cells were cocultivated with HZ (25μM HZ-heme), treated with HNE (7μM), or kept as untreated controls (CTRL) in liquid culture. (A) Cellular hemoglobin was quantified by the Drabkin method and expressed as micrograms per 106 cells. (B) The surface expression of CD34 and (C) glycophorin A was quantified by flow cytometry after immune staining and expressed as MFI. (D) CD34 expression was monitored in erythroid cells cocultivated with unfed (Mo), HZ-fed (Mo + HZ) (25μM HZ-heme, corresponding to 12 RBCs/monocyte in terms of heme content), or RBC-fed (Mo + RBC) monocytes (50 RBCs/monocyte). Means ± SE of 3 independent experiments. The significance of differences (P < .05) between untreated and HZ- (*) or HNE-treated (§) cells (A-C), or between erythroid cells cocultivated with HZ-fed monocytes and unfed (*) or RBC-fed monocytes (§; D) are indicated. (E-F) GlycophorinA and CD34 measured by flow cytometry in erythroid cells at days 15 and 1 of coincubation with HZ (solid line filled space) and HNE (dotted line unfilled space) and in control erythroid cells (solid line, unfilled space). Background is plotted as dashed line.
