A three-step pathway comprising PLZF/miR-146a/CXCR4 controls megakaryopoiesis.
MicroRNAs (miRNAs or miRs) regulate diverse normal and abnormal cell functions. We have identified a regulatory pathway in normal megakaryopoiesis, involving the PLZF transcription factor, miR-146a and the SDF-1 receptor CXCR4. In leukaemic cell lines PLZF overexpression downmodulated miR-146a and upregulated CXCR4 protein, whereas PLZF knockdown induced the opposite effects. In vitro assays showed that PLZF interacts with and inhibits the miR-146a promoter, and that miR-146a targets CXCR4 mRNA, impeding its translation. In megakaryopoietic cultures of CD34(+) progenitors, PLZF was upregulated, whereas miR-146a expression decreased and CXCR4 protein increased. MiR-146a overexpression and PLZF or CXCR4 silencing impaired megakaryocytic (Mk) proliferation, differentiation and maturation, as well as Mk colony formation. Mir-146a knockdown induced the opposite effects. Rescue experiments indicated that the effects of PLZF and miR-146a are mediated by miR-146a and CXCR4, respectively. Our data indicate that megakaryopoiesis is controlled by a cascade pathway, in which PLZF suppresses miR-146a transcription and thereby activates CXCR4 translation.
Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, 00161 Rome, Italy. catherine.labbaye@iss.it
Catherine
C
Labbaye
Isabella
I
Spinello
Maria Teresa
MT
Quaranta
Elvira
E
Pelosi
Luca
L
Pasquini
Eleonora
E
Petrucci
Mauro
M
Biffoni
Eugenia Rosa
ER
Nuzzolo
Monia
M
Billi
Robin
R
Foà
Ercole
E
Brunetti
Francesco
F
Grignani
Ugo
U
Testa
Cesare
C
Peschle
D001483:Base Sequence; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D006410:Hematopoiesis / Q000502:physiology*; D006801:Humans; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D008533:Megakaryocytes / Q000166:cytology / Q000502:physiology*; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D014158:Transcription, Genetic
D051741:Kruppel-Like Transcription Factors; C542542:MIRN146 microRNA, human; D035683:MicroRNAs; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering; D019718:Receptors, CXCR4; C092037:ZBTB16 protein, human