RESUMEN
MicroRNA (miRNA) species (miR) regulate mRNA translation and are implicated as mediators of disease pathology via coordinated regulation of molecular effector pathways. Unraveling miR disease-related activities will facilitate future therapeutic interventions. miR-155 recently has been identified with critical immune regulatory functions. Although detected in articular tissues, the functional role of miR-155 in inflammatory arthritis has not been defined. We report here that miR-155 is up-regulated in synovial membrane and synovial fluid (SF) macrophages from patients with rheumatoid arthritis (RA). The increased expression of miR-155 in SF CD14(+) cells was associated with lower expression of the miR-155 target, Src homology 2-containing inositol phosphatase-1 (SHIP-1), an inhibitor of inflammation. Similarly, SHIP-1 expression was decreased in CD68(+) cells in the synovial lining layer in RA patients as compared with osteoarthritis patients. Overexpression of miR-155 in PB CD14(+) cells led to down-regulation of SHIP-1 and an increase in the production of proinflammatory cytokines. Conversely, inhibition of miR-155 in RA synovial CD14(+) cells reduced TNF-α production. Finally, miR-155-deficient mice are resistant to collagen-induced arthritis, with profound suppression of antigen-specific Th17 cell and autoantibody responses and markedly reduced articular inflammation. Our data therefore identify a role of miR-155 in clinical and experimental arthritis and suggest that miR-155 may be an intriguing therapeutic target.
Asunto(s)
Artritis Experimental/genética , Artritis Experimental/metabolismo , Artritis Reumatoide/genética , Artritis Reumatoide/metabolismo , Mediadores de Inflamación/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Animales , Artritis Experimental/inmunología , Artritis Experimental/patología , Artritis Reumatoide/inmunología , Artritis Reumatoide/patología , Secuencia de Bases , Estudios de Casos y Controles , Citocinas/biosíntesis , Humanos , Inositol Polifosfato 5-Fosfatasas , Ratones , Ratones Noqueados , Osteoartritis/genética , Osteoartritis/inmunología , Osteoartritis/metabolismo , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas , Monoéster Fosfórico Hidrolasas/genética , Monoéster Fosfórico Hidrolasas/metabolismo , Membrana Sinovial/inmunología , Membrana Sinovial/metabolismo , Membrana Sinovial/patologíaRESUMEN
OBJECTIVES: Macrophages are central to the inflammatory processes driving rheumatoid arthritis (RA) synovitis. The molecular pathways that are induced in synovial macrophages and thereby promote RA disease pathology remain poorly understood. METHODS: We used microarray to characterise the transcriptome of synovial fluid (SF) macrophages compared with matched peripheral blood monocytes from patients with RA (n=8). RESULTS: Using in silico pathway mapping, we found that pathways downstream of the cholesterol activated liver X receptors (LXRs) and those associated with Toll-like receptor (TLR) signalling were upregulated in SF macrophages. Macrophage differentiation and tumour necrosis factor α promoted the expression of LXRα. Furthermore, in functional studies we demonstrated that activation of LXRs significantly augmented TLR-driven cytokine and chemokine secretion. CONCLUSIONS: The LXR pathway is the most upregulated pathway in RA synovial macrophages and activation of LXRs by ligands present within SF augments TLR-driven cytokine secretion. Since the natural agonists of LXRs arise from cholesterol metabolism, this provides a novel mechanism that can promote RA synovitis.
Asunto(s)
Artritis Reumatoide/metabolismo , Macrófagos/metabolismo , Receptores Nucleares Huérfanos/biosíntesis , Líquido Sinovial/metabolismo , Receptores Toll-Like/fisiología , Anciano , Artritis Reumatoide/genética , Artritis Reumatoide/patología , Diferenciación Celular/fisiología , Citocinas/metabolismo , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Receptores X del Hígado , Macrófagos/efectos de los fármacos , Macrófagos/patología , Masculino , Persona de Mediana Edad , Monocitos/metabolismo , Análisis de Secuencia por Matrices de Oligonucleótidos/métodos , Receptores Nucleares Huérfanos/genética , Receptores Nucleares Huérfanos/fisiología , Transducción de Señal/fisiología , Sinovitis/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Regulación hacia ArribaRESUMEN
Conclusive resolution of an immune response is critical for the prevention of autoimmunity and chronic inflammation. We report that following co-culture with autologous CD4+CD25- responder T cells, human CD14+ monocytes and monocyte-derived macrophages become activated but also significantly more prone to apoptosis than monocytes/macrophages cultured alone. In contrast, in the presence of CD4+CD25+ regulatory T cells (Tregs), monocytes and macrophages survive whilst adopting an anti-inflammatory phenotype. The induction of monocyte death requires responder T cell activation and cell-contact between responder T cells and monocytes. We demonstrate a critical role for FAS/FAS-L ligation in responder T cell-induced monocyte killing since responder T cells, but not Tregs, upregulate FAS-ligand (FAS-L) mRNA, and induce FAS expression on monocytes. Furthermore, responder T cell-induced monocyte apoptosis is blocked by neutralising FAS/FAS-L interaction, and is not observed when monocytes from an autoimmune lymphoproliferative syndrome (ALPS) patient with complete FAS-deficiency are used as target cells. Finally, we show that responder T cell-induced killing of monocytes is impaired in patients with active rheumatoid arthritis (RA). Our data suggest that resolution of inflammation in the course of a healthy immune response is aided by the unperturbed killing of monocytes with inflammatory potential by responder T cells and the induction of longer-lived, Treg-induced, anti-inflammatory monocytes.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Proteína Ligando Fas/inmunología , Macrófagos/inmunología , Monocitos/inmunología , Linfocitos T Reguladores/inmunología , Receptor fas/inmunología , Apoptosis/inmunología , Artritis Reumatoide/inmunología , Artritis Reumatoide/metabolismo , Artritis Reumatoide/patología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Técnicas de Cocultivo , Citotoxicidad Inmunológica/inmunología , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Citometría de Flujo , Expresión Génica , Humanos , Subunidad alfa del Receptor de Interleucina-2/inmunología , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Receptores de Lipopolisacáridos/inmunología , Receptores de Lipopolisacáridos/metabolismo , Macrófagos/citología , Macrófagos/metabolismo , Monocitos/citología , Monocitos/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Linfocitos T Reguladores/citología , Linfocitos T Reguladores/metabolismo , Receptor fas/genética , Receptor fas/metabolismoRESUMEN
BACKGROUND: The TAM-receptor tyrosine kinase family, Tyro3, Axl and Mer are key to apoptotic cell clearance. Reduced phagocytic clearance in systemic lupus erythematosus (SLE) leads to prolonged exposure of nuclear autoantigen to the immune system. Here we measure the levels of TAM receptors and the phagocytic capacity of monocytes and macrophages in juvenile-onset SLE (JSLE). METHOD: Mer protein was measured on monocytes from JSLE, healthy control and JIA patients. JSLE, healthy control and JIA patients' plasma were analysed for soluble Mer (sMer), soluble Tyro3 (sTyro) and soluble Axl (sAxl). A phagocytosis assay measured the effect of JSLE serum on phagocytic potential of JSLE and control monocytes to engulf E. Coli bacteria and healthy macrophages to engulf apoptotic neutrophils. RESULTS: Mer receptor expression was significantly decreased on JSLE monocytes compared to healthy controls. Plasma sMer, sTyro and sAxl were significantly increased in JSLE patients compared to controls (p < 0.05). Adult healthy control macrophages had significantly decreased phagocytosis of E. Coli and apoptotic neutrophils in the presence of 10% JSLE serum compared to control serum (p < 0.05). CONCLUSION: JSLE patients have a decreased phagocytosis due to both serum and cell-derived factors. Significantly increased levels of sMer, sTyro3 and sAxl may be important factors contributing to the deficit in phagocytosis ability.
Asunto(s)
Lupus Eritematoso Sistémico/metabolismo , Lupus Eritematoso Sistémico/fisiopatología , Fagocitosis/fisiología , Proteínas Proto-Oncogénicas/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Receptores Inmunológicos/metabolismo , Proteínas ADAM/metabolismo , Proteína ADAM17 , Adolescente , Edad de Inicio , Apoptosis/fisiología , Artritis Juvenil/epidemiología , Artritis Juvenil/metabolismo , Artritis Juvenil/fisiopatología , Estudios de Casos y Controles , Niño , Preescolar , Escherichia coli/metabolismo , Femenino , Humanos , Lupus Eritematoso Sistémico/epidemiología , Masculino , Monocitos/metabolismo , Monocitos/patología , Neutrófilos/patología , Tirosina Quinasa c-Mer , Tirosina Quinasa del Receptor AxlRESUMEN
BACKGROUND: T cells are important to systemic lupus erythematosus (SLE) disease progression. This study determined the pro-inflammatory potential of T cells within the rare condition juvenile-onset SLE (JSLE). METHOD: IL-17A and Th1/Th2-related cytokine concentrations were measured in plasma/serum from JSLE patients (n = 19, n = 11) and HC (n = 18, n = 7). IL17A, RORC, IL23 and IL23R mRNA were measured in peripheral blood mononuclear cells (PBMCs) from JSLE and healthy controls (HC) (n = 12). Th17-associated cytokine expression was analysed in the supernatant of CD3/CD28 activated JSLE (n = 7) and HC (n = 6) PBMCs. RESULTS: JSLE plasma IL-17A level (21.5 ± 5.2 pg/ml) was higher compared to HC (7.2 ± 2.5 pg/ml, p = 0.028). No differences were found in Th1/Th2 cytokines levels. IL = 17A (p = 0.022), IL-6 (p = 0.028) and IL-21 (p = 0.003) concentrations were increased in supernatants from activated JSLE PBMCs. IL-17 F (p = 0.50) and IL-22 (p = 0.43) were also increased but were not statistically significant. IL17A and IL23 mRNA was significantly higher in JSLE PBMCs (p = 0.018 and p = 0.01). CONCLUSION: JSLE T cells have an increased ability to secrete Th17 associated cytokines once activated, which could contribute to the pro-inflammatory disease phenotype seen in these patients.