Hematopoietic CD34+ cells differentiated into megakaryocytes accumulate PAF-AH activity. Freshly isolated CD34+ cells (culture day 0), megakaryocyte precursors (culture day 7), or megakaryocytes (culture day 13) adherent to immobilized fibrinogen were used for panels A through D. (A) Wheat germ agglutinin (WGA, green) and integrin αIIb (red) localization; representative of more than 10 independent experiments. Scale bar represents 50 μm. (B) Plasma PAF-AH mRNA was quantified by qRT-PCR and relative values of megakaryocyte precursors and megakaryocytes, normalized to β-actin, were compared with culture day 0 (CD34+ cells). The bars are the mean ± SD for 3 independent experiments. * indicates statistical significance (P < .05) compared with freshly isolated CD34+ cells or megakaryocyte precursors. (C) Plasma PAF-AH localization in megakaryocytes. Results are representative of 3 experiments. (D) PAF-AH activity in cell lysates. The bars in this graph represent the mean ± SD for 3 independent experiments. * indicates statistical significance (P < .05) compared with freshly isolated CD34+ cells or megakaryocyte precursors.
