Characterization of prostaglandin endoperoxide H synthase-1 enzyme expression during the differentiation of the megakaryocytic cell line, MEG-01.

Abstract

The specific objectives of my Master's project have been two-fold: to characterize the expression of prostaglandin endoperoxide synthase-1 (PGHS-1) protein and mRNA within the context of megakaryopoiesis, and to identify growth factors capable of inducing such expression. We induced MEG-01 cells to differentiate into platelet-like structures by treating them with TPA (12-0-tetradecanoylphorbol-13-acetate). We found that PGHS-1 protein levels were him in the platelet like population whereas PGHS-1 mRNA levels were greatest in the adherent population. We screened a number of recombinant hematopoietic factors for the ability to induce PGHS-1 protein expression in MEG-01 cells. We found that the combinations IL-3/IL-11/GM-CSF/SCF/TPO, IL-11/GM-CSF/SCF/TPO, IL-11/GM-CSF/TPO, IL-6/IL-11/GM-CSF/SCF, IL-6/IL-11, IL-3/IL-6, and IL 6/GM-CSF could induce PGHS-1 protein expression, but only when incubated with MEG-01 cultures that consisted solely of adherent cells. In conclusion, we have revealed that PGHS-1 protein and mRNA expression correlate strongly with megakaryocyte differentiation, and that certain cytokines can act in concert to stimulate adherent MEG-01 cells to increase their expression of PGHS-1 protein. The combination of IL-6 and -11 not only stimulates MEG-01 cells to increase their expression of PGHS-1 protein, but also PGHS-1 mRNA. (Abstract shortened by UMI.)