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Identification of microRNA-221/222 and microRNA-323-3p association with rheumatoid arthritis via predictions using the human tumour necrosis factor transgenic mouse model
  1. Ioannis Pandis1,
  2. Caroline Ospelt2,3,
  3. Niki Karagianni1,4,
  4. Maria C Denis4,
  5. Martin Reczko5,
  6. Carme Camps6,
  7. Artemis G Hatzigeorgiou5,
  8. Jiannis Ragoussis6,7,
  9. Steffen Gay2,3,
  10. George Kollias1
  1. 1Institute of Immunology, Biomedical Sciences Research Centre ‘Alexander Fleming’, Vari, Greece
  2. 2Center of Experimental Rheumatology, University Hospital Zurich, Zurich, Switzerland
  3. 3Zurich Center of Integrative Human Physiology, Zurich, Switzerland
  4. 4Biomedcode Hellas SA, Vari, Greece
  5. 5Institute of Molecular Oncology, Biomedical Sciences Research Centre ‘Alexander Fleming’, Vari, Greece
  6. 6The Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, UK
  7. 7Institute of Molecular Biology and Genetics, Biomedical Sciences Research Centre, Vari, Greece
  1. Correspondence to George Kollias, Biomedical Sciences Research Centre ‘Alexander Fleming’, Institute of Immunology, Vari 16672, Greece; kollias{at}


Objective To identify novel microRNA (miR) associations in synovial fibroblasts (SF), by performing miR expression profiling on cells isolated from the human tumour necrosis factor (TNF) transgenic mouse model (TghuTNF, Tg197) and patients biopsies.

Methods miR expression in SF from TghuTNF and wild-type (WT) control mice were determined by miR deep sequencing (miR-seq) and the arthritic profile was established by pairwise comparisons. Quantitative PCR analysis was utilised for profile validation, miR and gene quantitation in patient SF. Dysregulated miR target genes and pathways were predicted via bioinformatic algorithms and validated using gain-of-function coupled with reporter assay experiments.

Results miR-seq demonstrated that TghuTNF-SF exhibit a distinct pathogenic profile with 22 significantly upregulated and 30 significantly downregulated miR. Validation assays confirmed the dysregulation of miR-223, miR-146a and miR-155 previously associated with human rheumatoid arthritis (RA) pathology, as well as that of miR-221/222 and miR-323-3p. Notably, the latter were also found significantly upregulated in patient RA SF, suggesting for the first time their association with RA pathology. Bioinformatic analysis suggested Wnt/cadherin signalling as a putative pathway target. miR-323-3p overexpression was shown to enhance Wnt pathway activation and decrease the levels of its predicted target β-transducin repeat containing, an inhibitor of β-catenin.

Conclusions Using miR-seq-based profiling in SF from the TghuTNF mouse model and validations in RA patient biopsies, the authors identified miR-221/222 and miR-323-3p as novel dysregulated miR in RA SF. Furthermore, the authors show that miR-323-3p is a positive regulator of WNT/cadherin signalling in RA SF suggesting its potential pathogenic involvement and future use as a therapeutic target in RA.

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  • Funding This project was funded by the Masterswitch Project (HEALTH-F2-2008–223404), EURO-RA RTN (HPRN-CT-2002-00255) and IMI BtCure (grant agreement no. 115142) grants to GK and SG. JR was supported by the Wellcome Trust grant 075491/Z/04. SG also received funding from IAR-EPALINGES.

  • Ethics approval The local ethics committee approved the study.

  • Patient consent Obtained.

  • Competing interests None.

  • Provenance and peer review Not commissioned; externally peer reviewed.