title: Induction of apoptosis in the synovium of mice with autoantibody-mediated arthritis by the intraarticular injection of double-stranded MicroRNA-15a.
abstract: OBJECTIVE
  MicroRNA is a family of noncoding RNAs that exhibit tissue-specific or developmental stage-specific expression patterns and are associated with human diseases. MicroRNA-15a (miR-15a) is reported to induce cell apoptosis by negatively regulating the expression of Bcl-2, which suppresses the apoptotic processes. The purpose of this study was to investigate whether double-stranded miR-15a administered by intraarticular injection could be taken up by cells and could induce Bcl-2 dysfunction and cell apoptosis in the synovium of arthritic mice in vivo.
  
  
  METHODS
  Autoantibody-mediated arthritis was induced in male DBA/1J mice. In the experimental group, double-stranded miR-15a labeled with FAM-atelocollagen complex was injected into the knee joint. In the control group, control small interfering RNA-atelocollagen complex was injected into the knee joint. Synovial expression of miR-15a was analyzed by quantitative polymerase chain reaction, FAM by fluorescence microscopy, Bcl-2 by Western blotting, and Bcl-2 and caspase 3 by immunohistochemistry.
  
  
  RESULTS
  The expression of miR-15a in the synovium of the experimental group was significantly higher than that in the control group. Green fluorescence emission of FAM was observed in the synovium of the experimental group. Bcl-2 protein was down-regulated and the expression of caspase 3 was increased as compared with that in the control group.
  
  
  CONCLUSIONS
  These results indicate that the induction of cell apoptosis after intraarticular injection of double-stranded miR-15a occurs through inhibition of the translation of Bcl-2 protein in arthritic synovium.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nagata
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakasa
authors.forename: Yu
authors.initials: Y
authors.lastname: Mochizuki
authors.forename: Masakazu
authors.initials: M
authors.lastname: Ishikawa
authors.forename: Shigeru
authors.initials: S
authors.lastname: Miyaki
authors.forename: Hayatoshi
authors.initials: H
authors.lastname: Shibuya
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Yamasaki
authors.forename: Nobuo
authors.initials: N
authors.lastname: Adachi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asahara
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ochi
mesh_terms: D000276:Adjuvants, Immunologic / Q000009:adverse effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001169:Arthritis, Experimental / Q000378:metabolism* / Q000473:pathology; D001323:Autoantibodies / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D007270:Injections, Intra-Articular; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D035683:MicroRNAs / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology
chemical_list: D000276:Adjuvants, Immunologic; D001323:Autoantibodies; D035683:MicroRNAs; C544301:Mirn15a microRNA, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D012330:RNA, Double-Stranded; D053148:Caspase 3