title: FIP1L1-PDGFRalpha imposes eosinophil lineage commitment on hematopoietic stem/progenitor cells.
abstract: Although leukemogenic tyrosine kinases (LTKs) activate a common set of downstream molecules, the phenotypes of leukemia caused by LTKs are rather distinct. Here we report the molecular mechanism underlying the development of hypereosinophilic syndrome/chronic eosinophilic leukemia by FIP1L1-PDGFRalpha. When introduced into c-Kit(high)Sca-1(+)Lineage(-) cells, FIP1L1-PDGFRalpha conferred cytokine-independent growth on these cells and enhanced their self-renewal, whereas it did not immortalize common myeloid progenitors in in vitro replating assays and transplantation assays. Importantly, FIP1L1-PDGFRalpha but not TEL-PDGFRbeta enhanced the development of Gr-1(+)IL-5Ralpha(+) eosinophil progenitors from c-Kit(high)Sca-1(+)Lineage(-) cells. FIP1L1-PDGFRalpha also promoted eosinophil development from common myeloid progenitors. Furthermore, when expressed in megakaryocyte/erythrocyte progenitors and common lymphoid progenitors, FIP1L1-PDGFRalpha not only inhibited differentiation toward erythroid cells, megakaryocytes, and B-lymphocytes but aberrantly developed eosinophil progenitors from megakaryocyte/erythrocyte progenitors and common lymphoid progenitors. As for the mechanism of FIP1L1-PDGFRalpha-induced eosinophil development, FIP1L1-PDGFRalpha was found to more intensely activate MEK1/2 and p38(MAPK) than TEL-PDGFRbeta. In addition, a MEK1/2 inhibitor and a p38(MAPK) inhibitor suppressed FIP1L1-PDGFRalpha-promoted eosinophil development. Also, reverse transcription-PCR analysis revealed that FIP1L1-PDGFRalpha augmented the expression of C/EBPalpha, GATA-1, and GATA-2, whereas it hardly affected PU.1 expression. In addition, short hairpin RNAs against C/EBPalpha and GATA-2 and GATA-3KRR, which can act as a dominant-negative form over all GATA members, inhibited FIP1L1-PDGFRalpha-induced eosinophil development. Furthermore, FIP1L1-PDGFRalpha and its downstream Ras inhibited PU.1 activity in luciferase assays. Together, these results indicate that FIP1L1-PDGFRalpha enhances eosinophil development by modifying the expression and activity of lineage-specific transcription factors through Ras/MEK and p38(MAPK) cascades.
authors.affiliation: Department of Hematology and Oncology, Osaka University Graduate School of Medicine, 2-2, Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Fukushima
authors.forename: Itaru
authors.initials: I
authors.lastname: Matsumura
authors.forename: Sachiko
authors.initials: S
authors.lastname: Ezoe
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Masato
authors.initials: M
authors.lastname: Yasumi
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Satoh
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Shibayama
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Atsushi
authors.initials: A
authors.lastname: Iwama
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Kanakura
mesh_terms: D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D002908:Chronic Disease; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004804:Eosinophils / Q000201:enzymology* / Q000473:pathology; D050982:GATA1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D050989:GATA2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells; D006801:Humans; D017681:Hypereosinophilic Syndrome / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System; D051379:Mice; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics; D014184:Transplantation, Homologous; D039221:mRNA Cleavage and Polyadenylation Factors / Q000235:genetics / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D000099232:Proto-Oncogene Protein Spi-1
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D016207:Cytokines; D050982:GATA1 Transcription Factor; D050989:GATA2 Transcription Factor; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D020796:Receptor, Platelet-Derived Growth Factor alpha; D015534:Trans-Activators; D039221:mRNA Cleavage and Polyadenylation Factors; D048051:p38 Mitogen-Activated Protein Kinases; D000099232:Proto-Oncogene Protein Spi-1; C494689:Gata1 protein, mouse; C494712:Gata2 protein, mouse; C482128:MAP2K2 protein, human; C479819:FIP1L1-PDGFRA fusion protein, human; C482125:MAP2K1 protein, human; C482127:Map2k1 protein, mouse; C482129:Map2k2 protein, mouse