Mir-34a in Rheumatoid Arthritis: characterisation of elevated synovial expression and association with treatment resistance

Tange, C. E., Alivernini, S., Gilchrist, D. S., Crawford, L., Rainey, A.-A., Baxter, D., McInnes, I. B. and Kurowska-Stolarska, M. (2013) Mir-34a in Rheumatoid Arthritis: characterisation of elevated synovial expression and association with treatment resistance. In: 77th Annual Meeting of the American College of Rheumatology / 48th Annual Meeting of the Association of Rheumatology Health Professionals, San Diego, CA, 26-30 Oct 2013., S403.

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Abstract

Background/Purpose: Cells of the monocyte/macrophage lineage are critical to RA pathogenesis: unravelling mechanisms underlying macrophage inflammatory gene expression should elucidate novel disease-associated pathways and thereby biomarkers and therapeutic targets. MicroRNA (miR) comprise small, non-coding RNA species that are key regulators of mammalian gene expression. We sought to define the expression and regulation of novel miR species that regulate RA macrophage biology.<p></p> Methods: Blood (PB; healthy controls and RA patients with defined treatment characteristics) or synovial fluid (SF; RA) CD14+ cells were purified using histopaque centrifugation and autoMACS bead separation. CD14+ cells were matured with M-CSF or GM-CSF for up to 7 days, or stimulated with various TLR ligands. For T cell -macrophage interaction, CD4+ T cells were cultured with TNF, IL-2, IL-6, prior to 24hr co-culture with M-CSF-matured CD14+ cells. miR expression and copy number was variously quantified in cells or tissues via TLDA, validatory qPCR and in situ hybridisation with specific primers and DIG or FITC labelled probes, respectively.<p></p> Results: Prior TLDA elicited several dysregulated miRs in RA SF compared to PB CD14+ cells, including miR-34a. Fold change and copy number PCR assays confirmed elevated miR-34a in RA SF cells (n=10; p <0.01). Crucially miR-34a was also elevated in PB CD14+ cells from biologic-resistant RA patients compared to cDMARD good responders or matched healthy controls (n=19–30), associating miR-34a expression with chronic, treatment-resistance. miR-34a expression correlated with disease activity assessed by swollen joint count. In situ hybridisation demonstrated elevated miR-34a expression in RA compared with noninflammatory and inflammatory OA synovial tissues (n=6); double fluorescent staining confirmed expression in lining and sub-lining layer CD68+ macrophages, plus adjacent cells of FLS morphology. miR-34a was rapidly upregulated during monocyte maturation induced by adherence, M-CSF or GM-CSF, but was not further enhanced by addition of TLR ligands (LPS, CLO97, PAM3, PolyIC, CpG). Similarly co-culture with RA derived SF (10%) enhanced miR-34a expression in monocytes. Finally, cognate interactions between CD4+ T cells and macrophages further enhanced miR-34a expression in the latter cells.<p></p> Conclusion: miR-34a expression is elevated in RA SF macrophages and in PB monocytes of treatment resistant RA patients where it correlates with clinical disease activity measures. miR-34a is upregulated by the maturation rich synovial microenvironment and by interactions with a activated T cells. Putative miR-34a molecular targets include NOTCH1 rendering it a plausible novel immune regulator in synovitis.<p></p>

Item Type:Conference Proceedings
Additional Information:<br>Special Issue: 2013 Annual Meeting Abstract Supplement</br> Arthritis and Rheumatism 65(10):403
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McInnes, Professor Iain and Gilchrist, Dr Derek and Kurowska-Stolarska, Dr Mariola and Tange, Miss Clare and Alivernini, Mr Stefano
Authors: Tange, C. E., Alivernini, S., Gilchrist, D. S., Crawford, L., Rainey, A.-A., Baxter, D., McInnes, I. B., and Kurowska-Stolarska, M.
College/School:College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Arthritis and Rheumatism
Publisher:Wiley-Blackwell
ISSN:0004-3591
ISSN (Online):1529-0131

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