Gene expression has recently been at the forefront of advance in personalized medicine, notably in the field of cancer and transplantation, providing a rational for a similar approach in rheumatoid arthritis (RA). RA is a prototypic inflammatory autoimmune disease with a poorly understood etiopathogenesis. Inflammation is the main feature of RA; however, many biological processes are involved at different stages of the disease. Gene expression signatures offer management tools to meet the current needs for personalization of RA patient's care. This review analyses currently available information with respect to RA diagnostic, prognostic and prediction of response to therapy with a view to highlight the abundance of data, whose comparison is often inconclusive due to the mixed use of material source, experimental methodologies and analysis tools, reinforcing the need for harmonization if gene expression signatures are to become a useful clinical tool in personalized medicine for RA patients.

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BackgroundMonocytes are dominant cells present within the inflamed synovium during osteoarthritis (OA). In mice, two functionally distinct monocyte subsets are described: pro-inflammatory Ly6Chigh and patrolling Ly6Clow monocytes. Alarmins S100A8/A9 locally released by the synovium during inflammatory OA for prolonged periods may be dominant proteins involved in stimulating recruitment of Ly6Chigh monocytes from the circulation to the joint. Our objective was to investigate the role of S100A8/A9 in the mobilization of Ly6Chigh and Ly6Clow monocytic populations to the inflamed joint in collagenase-induced OA (CiOA).MethodS100A8 was injected intra-articularly to investigate monocyte influx. CiOA was induced by injection of collagenase into knee joints of wild-type C57BL/6 (WT), and S100a9-/- mice. Mice were sacrificed together with age-matched saline-injected control mice (n = 6/group), and expression of monocyte markers, pro-inflammatory cytokines, and chemokines was determined in the synovium using ELISA and RT-qPCR. Cells were isolated from the bone marrow (BM), spleen, blood, and synovium and monocytes were identified using FACS.ResultsS100A8/A9 was highly expressed during CiOA. Intra-articular injection of S100A8 leads to elevated expression of monocyte markers and the monocyte-attracting chemokines CCL2 and CX3CL1 in the synovium. At day 7 (d7) after CiOA induction in WT mice, numbers of Ly6Chigh, but not Ly6Clow monocytes, were strongly increased (7.6-fold) in the synovium compared to saline-injected controls. This coincided with strong upregulation of CCL2, which preferentially attracts Ly6Chigh monocytes. In contrast, S100a9-/- mice showed a significant increase in Ly6Clow monocytes (twofold) within the synovium at CiOA d7, whereas the number of Ly6Chigh monocytes remained unaffected. In agreement with this finding, the Ly6Clow mobilization marker CX3CL1 was significantly higher within the synovium of S100a9-/- mice. Next, we studied the effect of S100A8/A9 on release of Ly6Chigh monocytes from the BM into the circulation. A 14% decrease in myeloid cells was found in WT BM at CiOA d7. No decrease in myeloid cells in S100a9-/- BM was found, suggesting that S100A8/A9 promotes the release of myeloid populations from the BM.ConclusionInduction of OA locally leads to strongly elevated S100A8/A9 expression and an elevated influx of Ly6Chigh monocytes from the BM to the synovium.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-017-1426-6) contains supplementary material, which is available to authorized users.

Rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) do not express the coxsackie-adenovirus (Ad) receptor and are poorly permissive to Ad serotype 5 (Ad5). Genetically modified, coxsackie-Ad receptor-independent Ad5 vectors were studied for gene delivery in human RA FLS and synovium explants and murine collagen-induced arthritis. Short-fiber Ad5 vectors with seven fiber shaft repeats Ad5GFP-R7-knob, Ad5GFP-R7-arginine-glycine-aspartic acid (RGD) (RGD-liganded), and Ad5GFPΔknob (knob-deleted) were compared with Ad5GFP-FiWT, a conventional wild-type (WT) Ad5 vector. Gene transfer by Ad5GFP-R7-knob and Ad5GFP-R7-RGD was 40- to 50-fold and 25-fold higher, respectively, than Ad5GFP-FiWT in FLS. Ad5GFPΔknob was more efficacious than its knob-bearing version Ad5GFP-R7-knob in FLS transduction. Virus attachment and entry required RGD- and LDV-binding integrins including αv, αvβ3, avβ5, and β1. Ad5GFP-R7-knob infection of FLS was partially neutralized by synovial fluid (SF), but remained 30- to 40-fold higher than Ad5GFP-FiWT in the presence of SF. Ad5GFPΔknob was partially neutralized by SF at low virus input, but escaped viral neutralization by SF at higher virus input. Gene transfer to human synovium ex vivo explants and murine collagen-induced arthritis in vivo was also more efficient with short fiber-modified vectors (with and without the knob domain) than Ad5GFPFiWT. Gene transfer by short fiber-modified vectors was enhanced by inflammatory cytokines in vitro and in the presence of inflammation in murine synovium in vivo. Our data indicated that the highly efficient gene delivery RA was mediated by RGD- and non-RGD-binding integrins and enhanced by inflammation. Short fiber modifications with knob ablation may be a strategy to enhance gene delivery, reducing vector dose and vector-induced inflammation and toxicity.

The synthesis of asymmetric spherical nanoparticles has attracted great interest because their anisotropic structure can be used as unique building blocks for constructing advanced materials. In this article, we report the formation of hemispherical or truncated polystyrene/nanosaponite composite particles via one‐pot miniemulsion polymerization. It was found that the morphology of final composite latex particles strongly depends on the size of the nanoclay and its surface properties. Hemisphere or truncated sphere is the dominant morphology if the size of the nanoclay is larger than 100 nm. With the increase of the nanoclay content (up to 30 wt %), the fraction of hemispherical or truncated polystyrene/nanosaponite composite latex particles increased accordingly. The formation of hemispherical particles is possibly attributed to either the asymmetric growth of polymer chains on one side of the hydrophobically modified clay or the mechanical peeling‐off of large spherical particles between polymer and saponite. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013