Abnormalities of GATA-1 in megakaryocytes from patients with idiopathic myelofibrosis.
The abnormal megakaryocytopoiesis associated with idiopathic myelofibrosis (IM) plays a role in its pathogenesis. Because mice with defective expression of transcription factor GATA-1 (GATA-1(low) mutants) eventually develop myelofibrosis, we investigated the occurrence of GATA-1 abnormalities in IM patients. CD 34(+) cells were purified from 12 IM patients and 8 controls; erythroblasts and megakaryocytes were then obtained from unilineage cultures of CD 34(+) cells. Purified CD 61(+), GPA(+), and CD 34(+) cells from IM patients contained levels of GATA-1, GATA-2, and FOG-1 mRNA, as well as of GATA-2 protein, that were similar to controls. In contrast, CD 61(+) cells from IM patients contained significantly reduced GATA-1 protein. Furthermore, 45% of megakaryocytes in biopsies from IM patients did not stain with anti-GATA-1 antibody, as compared to controls (2%), essential thrombocythemia (4%), or polycythemia vera (11%) patients. Abnormalities in immunoreactivity for FOG-1 were not found, and no mutations in GATA-1 coding sequences were found. The presence of GATA-1(neg) megakaryocytes in bone marrow biopsies was independent of the Val 617 Phe JAK 2 mutation, making it unlikely that a downstream functional relationship exists. We conclude that megakaryocytes from IM patients have reduced GATA-1 content, possibly contributing to disease pathogenesis as in the GATA-1(low) mice and also representing a novel IM-associated marker.
Vannucchi
Alessandro M
AM
Department of Hematology, University of Florence, Florence, Italy. amvannucchi@unifi.it
Pancrazzi
Alessandro
A
Guglielmelli
Paola
P
Di Lollo
Simonetta
S
Bogani
Costanza
C
Baroni
Gianna
G
Bianchi
Lucia
L
Migliaccio
Anna Rita
AR
Bosi
Alberto
A
Paoletti
Francesco
F
D000906:Antibodies / Q000378:metabolism; D016022:Case-Control Studies; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000276:immunology / Q000378:metabolism; D050981:Erythroid-Specific DNA-Binding Factors; D005260:Female; D050982:GATA1 Transcription Factor; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D039661:Integrin beta3 / Q000378:metabolism; D008297:Male; D008533:Megakaryocytes / Q000378:metabolism* / Q000473:pathology; D011087:Polycythemia Vera / Q000378:metabolism / Q000473:pathology; D055728:Primary Myelofibrosis / Q000378:metabolism* / Q000473:pathology; D013194:Staining and Labeling; D013922:Thrombocytosis / Q000378:metabolism / Q000473:pathology; D014157:Transcription Factors / Q000172:deficiency* / Q000276:immunology / Q000378:metabolism
D000906:Antibodies; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D039661:Integrin beta3; D014157:Transcription Factors