CCL2 and rheumatoid arthritis: Consistent with this, enforced expression of miR-155 via transfection with miR-155-5p mimic, increased basal release of IL-6 and CCL2 by SFs from each of Naïve, CIA and CIA-ES-62 mice and this was associated with profound suppression of SOCS1 (Fig 4I–4K), as previously reported for the association between high levels of miR-155 and IL-1β and TNFα in peripheral blood from RA patients [41].