title: MicroRNA-17 Suppresses TNF-α Signaling by Interfering with TRAF2 and cIAP2 Association in Rheumatoid Arthritis Synovial Fibroblasts.
abstract: TNF-α is a major cytokine implicated in rheumatoid arthritis (RA), and its expression is regulated at the transcriptional and posttranscriptional levels. However, the impact of changes in microRNA expression on posttranslational processes involved in TNF-α signaling networks is not well defined in RA. In this study, we evaluated the effect of miR-17, a member of the miR-17-92 cluster, on the TNF-α signaling pathway in human RA synovial fibroblasts (SFs). We demonstrated that miR-17 expression was significantly low in RA serum, SFs, and synovial tissues, as well as in the serum and joints of adjuvant-induced arthritis rats. RNA-sequencing analysis showed modulation of 664 genes by pre-miR-17 in human RA SFs. Ingenuity pathway analysis of RNA-sequencing data identified the ubiquitin proteasome system in the TNF-α signaling pathway as a primary target of miR-17. Western blot analysis confirmed the reduction in TRAF2, cIAP1, cIAP2, USP2, and PSMD13 expression by miR-17 in TNF-α-stimulated RA SFs. Immunoprecipitation assays showed that miR-17 restoration increased the K48-linked polyubiquitination of TRAF2, cIAP1, and cIAP2 in TNF-α-stimulated RA SFs. Thus, destabilization of TRAF2 by miR-17 reduced the ability of TRAF2 to associate with cIAP2, resulting in the downregulation of TNF-α-induced NF-κBp65, c-Jun, and STAT3 nuclear translocation and the production of IL-6, IL-8, MMP-1, and MMP-13 in human RA SFs. In conclusion, this study provides evidence for the role of miR-17 as a negative regulator of TNF-α signaling by modulating the protein ubiquitin processes in RA SFs.
authors.affiliation: Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, WA 99210.
authors.forename: Nahid
authors.initials: N
authors.lastname: Akhtar
authors.affiliation: Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, WA 99210.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Singh
authors.affiliation: Department of Pharmaceutical Sciences, Washington State University College of Pharmacy, Spokane, WA 99210 salah.ahmed@wsu.edu.
authors.forename: Salahuddin
authors.initials: S
authors.lastname: Ahmed
mesh_terms: D001172:Arthritis, Rheumatoid / Q000209:etiology / Q000276:immunology*; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D005347:Fibroblasts / Q000276:immunology; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000502:physiology; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis; D035683:MicroRNAs / Q000502:physiology*; D016328:NF-kappa B / Q000502:physiology; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D013583:Synovial Membrane / Q000276:immunology*; D047992:TNF Receptor-Associated Factor 2 / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000502:physiology*
chemical_list: D016207:Cytokines; D051034:Inhibitor of Apoptosis Proteins; C524941:MIRN17 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D047992:TNF Receptor-Associated Factor 2; D014409:Tumor Necrosis Factor-alpha; D025801:Ubiquitin; C494832:BIRC3 protein, human; D000075747:Baculoviral IAP Repeat-Containing 3 Protein; D044767:Ubiquitin-Protein Ligases; D020781:Matrix Metalloproteinase 1