Developmental expression of plasminogen activator inhibitor-1 associated with thrombopoietin-dependent megakaryocytic differentiation.
Plasminogen activator inhibitor-1 (PAI-1) is present in the platelet alpha-granule and is released on activation. However, there is some debate as to whether the megakaryocyte and platelet synthesize PAI-1, take it up from plasma, or both. We examined the expression of PAI-1 in differentiating megakaryocytic progenitor cells (UT-7) and in CD34(+)/CD41(-) cells from cord blood. UT-7 cells differentiated with thrombopoietin (TPO) resembled megakaryocytes (UT-7/TPO) with respect to morphology, ploidy, and the expression of glycoprotein IIb-IIIa. PAI-1 messenger RNA (mRNA) expression was upregulated and PAI-1 protein synthesized in the UT-7/TPO cells accumulated in the cytoplasm without being released spontaneously. In contrast, erythropoietin (EPO)-stimulated UT-7 cells (UT-7/EPO) did not express PAI-1 mRNA after stimulation with TPO because they do not have endogenous c-Mpl. After cotransfection with human wild-type c-mpl, the cells (UT-7/EPO-MPL) responded to phorbol 12-myristate 13-acetate (PMA), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) with enhanced PAI-1 mRNA expression within 24 to 48 hours. However, induction of PAI-1 mRNA in UT-7/EPO-MPL cells by TPO required at least 14-days stimulation. UT-7/EPO cells expressing c-Mpl changed their morphology and the other characteristics similar to the UT-7/TPO cells. TPO also differentiated human cord blood CD34(+)/CD41(-) cells to CD34(-)/CD41(+) cells, generated morphologically mature megakaryocytes, and induced the expression of PAI-1 mRNA. These results suggest that both PAI-1 mRNA and de novo PAI-1 protein synthesis is induced after differentiation of immature progenitor cells into megakaryocytes by TPO.
Madoiwa
S
S
Division of Hemostasis and Thrombosis, Institute of Hematology, Division of Hematology, Department of Medicine, Jichi Medical School, Tochigi-ken, Japan.
Komatsu
N
N
Mimuro
J
J
Kimura
K
K
Matsuda
M
M
Sakata
Y
Y
D015415:Biomarkers; D002454:Cell Differentiation / Q000187:drug effects; D003114:Colony-Forming Units Assay; D018076:DNA, Complementary / Q000235:genetics; D004921:Erythropoietin / Q000494:pharmacology; D005312:Fetal Blood / Q000166:cytology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D006801:Humans; D007947:Leukemia, Megakaryoblastic, Acute / Q000473:pathology; D008533:Megakaryocytes / Q000187:drug effects / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis* / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013926:Thrombopoietin / Q000494:pharmacology*; D014162:Transfection; D014407:Tumor Cells, Cultured
D015415:Biomarkers; D018076:DNA, Complementary; D009363:Neoplasm Proteins; D017395:Plasminogen Activator Inhibitor 1; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D011994:Recombinant Proteins; D004921:Erythropoietin; C082218:MPL protein, human; D013926:Thrombopoietin; D013755:Tetradecanoylphorbol Acetate