ISR Autumn Meeting 2019
2nd Place Scientific Oral Presentation
Distinct monocyte and macrophage inflammatory and bioenergetic profiles in Rheumatoid Arthritis
Hanlon MM (1), McGarry T (1) , Canavan M(1) , Low C (2), Wade S (1), Nagpal S (3) Veale DJ (2), Fearon U (1)
(1) Molecular Rheumatology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland (2) Centre for Arthritis & Rheumatic Diseases, Dublin Academic Medical Centre, University College Dublin, Ireland (3) Immunology, Janssen Research & Development, 1400 McKean Road, Spring House, PA 19477, USA;
Monocytes and macrophages play a key role in RA disease progression, however, the diversity and plasticity of cell subsets and their metabolic profile in inflammatory arthritis has yet to be elucidated.
To elucidate the inflammatory and metabolic profiles/function of RA monocytes and macrophages and fully characterise RA synovial tissue macrophage subsets.
CD14+ monocytes from RA, Arthralgia and HC bloods were isolated and examined ex-vivo or following differentiation into M1/M2 macrophages. Inflammatory mediators, metabolic markers and transcriptional activity was determined by RT-PCR and western blot, and phagocytosis capacity by OVA-albumin assays. Glycolysis (ECAR) and oxidative phosphorylation (OCR) were quantified by Seahorse-XFE-technology. Single cell synovial-tissue suspensions from RA,PsA and OA biopsies and synovial fluid cells were analysed for macrophage subsets (CD40,-CD45,-CD64,-CD68,-CD163,-CD206,-CD253) by flow cytometry. Double positive CD206+CD163+ vs CD206-CD163- cells were sorted by FACSAria Fusion sorter and RNAseq transcriptomic analysis performed.
RA monocytes are hyperinflammatory, with significantly higher expression of IL-1β,TNFα,IL-6,OSM,CXCL10 and CXCL11 compared to HC (all p<0.05), this profile is maintained in monocyte-derived M1-macrophages and M2 macrophages with impaired phagocytic capacity observed. In parallel, an increase in HIF1α and PFKFB3 (a key glycolytic enzyme) was observed compared to HC (all-p<0.05). Baseline glycolysis (p<0.05), the maximal glycolytic capacity (p<0.05) and the ECAR:OCR ratio were increased in RA CD14+ monocytes and RA M1 macrophages compared to HC (p<0.05). Interestingly, this pro-hyperinflammatory/metabolic phenotype was also evident in CD14+ monocytes from arthralgia ACPA+/RF+ subjects. Transcriptional activation of STAT3 induced this hyperinflammatory/metabolic phenotype, with STAT3-inhibition resulting in metabolic reprogramming and resolution of inflammation. A significant enrichment of a dominant double positive CD206+CD163+ compared to CD206-CD163- macrophages was demonstrated in synovial-tissue versus fluid (p<0.05), with a significant increase in the frequency of CD206+CD163+CD40+ macrophages in RA synovial-tissue compared to PsA and OA (p<0.05). Finally, RNAseq revealed differential expression of genes involved in immune activation, cell adhesion and metabolism in CD206+CD163+ vs CD206-CD163- synovial tissue macrophages.
This study demonstrates a unique inflammatory and metabolic phenotype of RA monocytes/macrophages, a phenotype that may precede disease onset. Furthermore we have identified, for the first time, enrichment of a dominant transcriptionally distinct macrophage subtype in RA synovial-tissue.