Effect of PEG-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on growth and differentiation of the HEL cell line

Abstract

BACKGROUND AND OBJECTIVE: Thrombopoietin has been established as the major regulator of megakaryocyte and platelet production. In this study we evaluated the effects of PEG-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF), a pegylated and truncated form of thrombopoietin, on the growth and differentiation of the HEL cell line. As a model system we chose the pluripotent HEL line that acquires multiple markers of the megakaryocyte/platelet phenotype following treatment with phorbol esters, and, more importantly, expresses the receptor for thrombopoietin (Mpl receptor) at its cellular surface. DESIGN AND METHODS: The effect of PEG-rHuMGDF on HEL proliferation/differentiation was evaluated in a liquid culture assay. RESULTS: Peg-rHuMGDF do not increase the proliferative capacity of HEL cell but, in parallel experiments, HEL cells showed a more mature and differentiated pattern after exposure to the cytokine. Our results show that PEG-rHuMGDF, at the optimal doses of 100-150 ng/mL, is able to induce: 1) morphological changes with the formation of cytoplasmic protrusions; 2) increased ploidy as demonstrated by cytofluorimetric analysis; 3) increased expression of megakaryocyte markers, including glycoprotein IIb-IIIa and the platelet-specific alloantigen (PIA1). INTERPRETATION AND CONCLUSIONS: These findings show that HEL cells represent a useful model to investigate the differentiative properties of thrombopoietin in the megakaryocyte compartment.