title: MicroRNA-146a expresses in interleukin-17 producing T cells in rheumatoid arthritis patients.
abstract: BACKGROUND
  Interleukin (IL)-17 is an important factor in rheumatoid arthritis (RA) pathogenesis. MicroRNA (miRNA)s are a family of non coding RNAs and associated with human diseases including RA. The purpose of this study is to identify the miRNAs in the differentiation of IL-17 producing cells, and analyze their expression pattern in the peripheral blood mononuclear cells (PBMC) and synovium from RA patients.
  
  
  METHODS
  IL-17 producing cells were expanded from CD4+T cell. MiRNA microarray was performed to identify the miRNAs in the differentiation of IL-17 producing cells. Quantitative polymerase chain reaction was performed to examine the expression patterns of the identified miRNAs in the PBMC and synovium from RA and osteoarthritis (OA) patients. Double staining combining in situ hybridization and immunohistochemistry of IL-17 was performed to analyze the expression pattern of identified miRNA in the synovium.
  
  
  RESULTS
  Six miRNAs, let-7a, miR-26, miR-146a/b, miR-150, and miR-155 were significantly up regulated in the IL-17 producing T cells. The expression of miR-146a and IL-17 was higher than in PBMC in the patients with low score of Larsen grade and short disease duration. MiR-146a intensely expressed in RA synovium in comparison to OA. MiR-146a expressed intensely in the synovium with hyperplasia and high expression of IL-17 from the patients with high disease activity. Double staining revealed that miR-146a expressed in IL-17 expressing cells.
  
  
  CONCLUSIONS
  These results indicated that miR-146a was associated with IL-17 expression in the PBMC and synovium in RA patients. There is the possibility that miR-146a participates in the IL-17 expression.
authors.affiliation: Department of Orthopaedic Surgery, Programs for Applied Biomedicine, Division of Clinical Medical Science, Graduate School of Biomedical Sciences, 1-2-3, Kasumi, Minami-ku, Hiroshima 734-8551 Japan. tnakasa@smn.enjoy.ne.jp
authors.forename: Takuya
authors.initials: T
authors.lastname: Niimoto
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakasa
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okuhara
authors.forename: Bunichiro
authors.initials: B
authors.lastname: Izumi
authors.forename: Masataka
authors.initials: M
authors.lastname: Deie
authors.forename: Osami
authors.initials: O
authors.lastname: Suzuki
authors.forename: Nobuo
authors.initials: N
authors.lastname: Adachi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D006801:Humans; D020381:Interleukin-17 / Q000096:biosynthesis* / Q000235:genetics; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D008875:Middle Aged; D013583:Synovial Membrane / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology
chemical_list: D020381:Interleukin-17; D035683:MicroRNAs; C534190:Mirn146 microRNA, mouse