title: Mechanisms of Impaired Neutrophil Migration by MicroRNAs in Myelodysplastic Syndromes.
abstract: In myelodysplastic syndromes (MDS), functional defects of neutrophils result in high mortality because of infections; however, the molecular basis remains unclear. We recently found that miR-34a and miR-155 were significantly increased in MDS neutrophils. To clarify the effects of the aberrant microRNA expression on neutrophil functions, we introduced miR-34a, miR-155, or control microRNA into neutrophil-like differentiated HL60 cells. Ectopically introduced miR-34a and miR-155 significantly attenuated migration toward chemoattractants fMLF and IL-8, but enhanced degranulation. To clarify the mechanisms for inhibition of migration, we studied the effects of miR-34a and miR-155 on the migration-regulating Rho family members, Cdc42 and Rac1. The introduced miR-34a and miR-155 decreased the fMLF-induced active form of Cdc42 to 29.0 ± 15.9 and 39.7 ± 4.8% of that in the control cells, respectively, although Cdc42 protein levels were not altered. miR-34a decreased a Cdc42-specific guanine nucleotide exchange factor (GEF), dedicator of cytokinesis (DOCK) 8, whereas miR-155 reduced another Cdc42-specific GEF, FYVE, RhoGEF, and PH domain-containing (FGD) 4. The knockdown of DOCK8 and FGD4 by small interfering RNA suppressed Cdc42 activation and fMLF/IL-8-induced migration. miR-155, but not miR-34a, decreased Rac1 protein, and introduction of Rac1 small interfering RNA attenuated Rac1 activation and migration. Neutrophils from patients showed significant attenuation in migration compared with healthy cells, and protein levels of DOCK8, FGD4, and Rac1 were well correlated with migration toward fMLF (r= 0.642, 0.686, and 0.436, respectively) and IL-8 (r= 0.778, 0.659, and 0.606, respectively). Our results indicated that reduction of DOCK8, FGD4, and Rac1 contributes to impaired neutrophil migration in MDS.
authors.affiliation: Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Meiwan
authors.initials: M
authors.lastname: Cao
authors.affiliation: Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan; yayois@fmu.ac.jp.|Center for Medical Education and Career Development, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Yayoi
authors.identifier: 0000-0001-5121-5130
authors.initials: Y
authors.lastname: Shikama
authors.affiliation: Department of Hematology, Kita-Fukushima Medical Center, Date 960-0502, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kimura
authors.affiliation: Department of Cardiology and Hematology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.|Department of Medical Oncology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan; and.
authors.forename: Hideyoshi
authors.initials: H
authors.lastname: Noji
authors.affiliation: Department of Cardiology and Hematology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.|Department of Blood Transfusion and Transplantation Immunology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Kazuhiko
authors.identifier: 0000-0002-5269-269X
authors.initials: K
authors.lastname: Ikeda
authors.affiliation: Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Ono
authors.affiliation: Department of Cardiology and Hematology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Kazuei
authors.initials: K
authors.lastname: Ogawa
authors.affiliation: Department of Cardiology and Hematology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Takeishi
authors.affiliation: Department of Pharmacology, School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Kimura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D049109:Cell Proliferation; D002633:Chemotaxis / Q000276:immunology; D002634:Chemotaxis, Leukocyte; D005260:Female; D020662:Guanine Nucleotide Exchange Factors / Q000172:deficiency / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018922:HL-60 Cells; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D008840:Microfilament Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000276:immunology*; D018375:Neutrophil Activation; D009504:Neutrophils / Q000276:immunology / Q000502:physiology*; D034741:RNA, Small Interfering; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000276:immunology; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000276:immunology
chemical_list: C516591:DOCK8 protein, human; C485164:FGD4 protein, human; D020662:Guanine Nucleotide Exchange Factors; D016209:Interleukin-8; C524942:MIRN155 microRNA, human; C522425:MIRN34 microRNA, human; D035683:MicroRNAs; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; D020764:cdc42 GTP-Binding Protein; D020830:rac1 GTP-Binding Protein