In vivo action of IL-27: reciprocal regulation of Th17 and Treg cells in collagen-induced arthritis

Interleukin (IL)-27 is a novel cytokine of the IL-6/IL-12 family that has been reported to be involved in the pathogenesis of autoimmune diseases and has a pivotal role as both a pro- and anti-inflammatory cytokine. We investigated the in vivo effects of IL-27 on arthritis severity in a murine collagen-induced arthritis (CIA) model and its mechanism of action regarding control of regulatory T (Tregs) and IL-17-producing T helper 17 (Th17) cells. IL-27-Fc-treated CIA mice showed a lower severity of arthritis. IL-17 expression in the spleens was significantly decreased in IL-27-Fc-treated CIA mice compared with that in the CIA model. The Th17 population was decreased in the spleens of IL-27-Fc-treated CIA mice, whereas the CD4+CD25+Foxp3+ Treg population increased. In vitro studies revealed that IL-27 inhibited IL-17 production in murine CD4+ T cells, and the effect was associated with retinoic acid-related orphan receptor gammaT and signal transducer and activator of transcription 3 inhibition. In contrast, fluorescein isothiocyanate-labeled forkhead box P3 (Foxp3) and IL-10 were profoundly augmented by IL-27 treatment. Regarding the suppressive capacity of Treg cells, the proportions of CTLA-4+ (cytotoxic T-lymphocyte antigen 4), PD-1+ (programmed cell death protein 1) and GITR+ (glucocorticoid-induced tumor necrosis factor receptor) Tregs increased in the spleens of IL-27-Fc-treated CIA mice. Furthermore, in vitro differentiated Treg cells with IL-27 exerted a more suppressive capacity on T-cell proliferation. We found that IL-27 acts as a reciprocal regulator of the Th17 and Treg populations in CD4+ cells isolated from healthy human peripheral blood mononuclear cells (PBMCs), as well as from humans with rheumatoid arthritis (RA) PBMCs. Our study suggests that IL-27 has the potential to ameliorate overwhelming inflammation in patients with RA through a reciprocal regulation of Th17 and Treg cells.

Comparison of the Child-Turcotte-Pugh Classification and the Model for End-stage Liver Disease Score as Predictors of the Severity of the Systemic Inflammatory Response in Patients Undergoing Living-donor Liver Transplantation

The aim of this study was to evaluate and compare the Child-Turcotte-Pugh (CTP) classification system and the model for end-stage liver disease (MELD) score in predicting the severity of the systemic inflammatory response in living-donor liver transplantation patients. Recipients of liver graft were allocated to a recipient group (n = 39) and healthy donors to a donor group (n = 42). The association between the CTP classification, the MELD scores and perioperative cytokine concentrations in the recipient group was evaluated. The pro-inflammatory cytokines measured included interleukin (IL)-1beta, IL-6, and tumor necrosis factor (TNF)-alpha; the anti-inflammatory cytokines measured included IL-10 and IL-4. Cytokine concentrations were quantified using sandwich enzyme-linked immunoassays. The IL-6, TNF-alpha, and IL-10 concentrations in the recipient group were significantly higher than those in healthy donor group patients. All preoperative cytokine levels, except IL-6, increased in relation to the severity of liver disease, as measured by the CTP classification. Additionally, all cytokine levels, except IL-6, were significantly correlated preoperatively with MELD scores. However, the correlations diminished during the intraoperative period. The CTP classification and the MELD score are equally reliable in predicting the severity of the systemic inflammatory response, but only during the preoperative period.

Measurement of Interleukin-33 (IL-33) and IL-33 Receptors (sST2 and ST2L) in Patients with Rheumatoid Arthritis

The interleukin-33 (IL-33)/ST2 pathway has emerged as an intercellular signaling system that participates in antigen-allergen response, autoimmunity and fibrosis. It has been suggested that IL-33/ST2 signaling has been involved in the pathogenesis of rheumatoid arthritis (RA), because IL-33 and its receptor have been specifically mapped to RA synovium. The aim of this study was to determine the levels of IL-33 and sST2 in sera and synovial fluids in patients with RA. The serum level of IL-33 was significantly higher in patients with RA (294.9 +/- 464.0 pg/mL) than in healthy controls (96.0 +/- 236.9 pg/mL, P = 0.002). The synovial fluid level of IL-33 was significantly higher in RA patients than in osteoarthritis patients. The level of serum sST2 was higher in RA patients than in healthy controls (P = 0.042). A significant relationship was found between the levels of IL-33 and IL-1beta (r = 0.311, P = 0.005), and IL-33 and IL-6 (r = 0.264, P = 0.017) in 81 RA patients. The levels of IL-33, sST2 and C-reactive protein decreased after conventional disease-modifying antirheumatic drugs treatment in 10 patients with treatment-naive RA. Conclusively, IL-33 is involved in the pathogenesis of RA and may reflect the degree of inflammation in patients with RA.

The Effect of Inflammatory Cytokines on the Differentiation of Th17 Cells in Human Peripheral Blood / 대한류마티스학회지

OBJECTIVE: IL-17-producing T cells (Th17 cells) have been identified as a distinct lineage of CD4+ T helper cells in mice. Since this discovery, many efforts have been made to investigate the characteristics and the role of human Th17 cells and the factors involved in their differentiation. This study was undertaken to assess the effects of cytokines and stimulatory conditions on the differentiation of human CD4+ T cells into Th17 cells. METHODS: Peripheral blood CD4+ T cells were isolated from healthy humans and then these cells were cultured with using various stimulatory conditions. The Th17 cells and regulatory T (Treg) cells were detected by flow cytometry (FACs). The related gene expressions of cytokines, transcription factors and chemokine receptors were determined by ELISA and RT-PCR. RESULTS: In the presence of inflammatory cytokines, TNFa and IL-1b, the human CD4+ T cells rapidly produced IL-17 in response to anti-CD3/anti-CD28 stimulation, whereas, with anti-CD3/anti-CD28 stimulation alone, the CD4+ T cells expressed low levels of IL-17. TNFa and IL-1b were also important inducers of IL-22 production. IL-6 and IL-23 up-regulated the RORgammat, CCR4 and CCR6 expressions in the human CD4+ T cells. In response to TGF-b and IL-2, the human CD4+ T cells were rapidly induced to express FoxP3, IL-10 and CCR7, as compared with anti-CD3/anti-CD28 stimulation alone. CONCLUSION: The effect of inflammatory cytokines on the differentiation of human Th17 cells may help us to understand their pathogenic role. Moreover, the differential expression of chemokine receptors and transcription factors of the subsets of CD4+ T cells with the different features of Th17 and Treg, may raise new issues concerning the pathogenesis of autoimmune inflammatory diseases.

IL-23 P19 Expression Induced by IL-17 and IL-1beta in Rheumatoid Arthritis Synovial Mononuclear Cells

Interleukin-23 (IL-23) is a novel pro-inflammatory cytokine which has been implicated to play a pathogenic role in rheumatoid arthritis (RA). This study was undertaken to investigate the IL-23 inductive activity of the proinflammatory cytokine IL-17, IL-1 beta and tumor necrosis factor (TNF-alpha) in RA synovial fluid mononuclear cells (SFMC). Expression of IL-23p19, IL-17, IL-1 beta and TNF-alpha in joint was examined by immunohistochemistry (IHC) of patients with RA and osteoarthritis (OA). The effects of IL-17 and IL-1 beta on expression of IL-23p19 in human SFMC from RA patients were determined by reverse transcriptase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-23p19 was expressed in the RA fibroblast like synoviocyte (FLS), but not from OA FLS. Similar to the protein expression, IL-23p19 mRNA could be detected by RT-PCR in RA SFMC. IL-17 and IL-1 beta could induce RA SFMC to produce the IL-23p19. The effects of IL-17 were much stronger than IL-1 beta or TNF-alpha. These responses were observed in a dose- responsive manner. In addition, IL-17 or IL-1 beta neutralizing antibody down-regulated the expression of IL-23p19 induced by LPS in RA-SFMC. Our results demonstrate that IL-23p19 is overexpressed in RA synovium and IL-17 and IL-1 beta appears to upregulate the expression of IL-23p19 in RA-SFMC.

IL-23 P19 Expression Induced by IL-17 and IL-1beta in Rheumatoid Arthritis Synovial Mononuclear Cells

Interleukin-23 (IL-23) is a novel pro-inflammatory cytokine which has been implicated to play a pathogenic role in rheumatoid arthritis (RA). This study was undertaken to investigate the IL-23 inductive activity of the proinflammatory cytokine IL-17, IL-1 beta and tumor necrosis factor (TNF-alpha) in RA synovial fluid mononuclear cells (SFMC). Expression of IL-23p19, IL-17, IL-1 beta and TNF-alpha in joint was examined by immunohistochemistry (IHC) of patients with RA and osteoarthritis (OA). The effects of IL-17 and IL-1 beta on expression of IL-23p19 in human SFMC from RA patients were determined by reverse transcriptase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). IL-23p19 was expressed in the RA fibroblast like synoviocyte (FLS), but not from OA FLS. Similar to the protein expression, IL-23p19 mRNA could be detected by RT-PCR in RA SFMC. IL-17 and IL-1 beta could induce RA SFMC to produce the IL-23p19. The effects of IL-17 were much stronger than IL-1 beta or TNF-alpha. These responses were observed in a dose- responsive manner. In addition, IL-17 or IL-1 beta neutralizing antibody down-regulated the expression of IL-23p19 induced by LPS in RA-SFMC. Our results demonstrate that IL-23p19 is overexpressed in RA synovium and IL-17 and IL-1 beta appears to upregulate the expression of IL-23p19 in RA-SFMC.

The Th17 and Autoimmune Arthritis

Autoimmune arthritis, such as rheumatoid arthritis (RA), is a chronic inflammatory disorder that primarily affects the joints and then results in their progressive destruction. Effector Th cells have been classified as Th1 and Th2 subsets based on their cytokine expression profiles and immune regulatory function. Another subset of T cells termed Th17 was recently discovered and known to selectively produce IL-17. Also, Th17 was shown to be generated by TGFbeta and IL-6 and maintained by IL-23. IL-17 is a proinflammatory cytokine that is considered to involve the development of various inflammatory autoimmune diseases such as RA, asthma, lupus, and allograft rejection. IL-17 is present in the sera, synovial fluids and synovial biopsies of most RA patient. IL-17 activates RA synovial fibroblasts to synthesize IL-6, IL-8 and VEGF via PI3K/Akt and NF-kappaB dependent pathway. IL-17 increases IL-6 production, collagen destruction and collagen synthesis. In addition, it not only causes bone resorption but also increases osteoclastogenesis and fetal cartilage destruction. Inhibition of the IL-17 production may contribute a novel therapeutic approach along with potent anti-inflammatory effect and with less immunosuppressive effect on host defenses.

Macrophage Migration Inhibitory Factor (MIF) Induced Stromal Cell-derived Factor 1 (SDF-1) Production Via Nuclear Factor KappaB (NF-kappaB) Signaling in Rheumatoid Arthritis Fibroblast Like Synoviocytes (RA-FLS)

BACKGROUND: Stromal cell-derived factor (SDF)-1 is a potent chemoattractant for activated T cells into the inflamed Rheumatoid arthritis (RA) synovium. To determine the effect of macrophage migration inhibitory factor (MIF) on the production of SDF-1 in the inflamed RA synovium. METHODS: The expression of SDF-1 and MIF in RA and Osteoarthritis (OA) synovium was examined by immunohistochemical staining. The SDF-1 was quantified by RT-PCR and ELISA after RA fibroblast like synoviocyte (FLS) were treated with MIF in the presence and absence of inhibitors of intracellular signal molecules. The synovial fluid (SF) and serum levels of MIF and SDF-1 in RA, OA and healthy control were measured by ELISA. RESULTS: Expression of SDF-1 and MIF in synovium was higher in RA patients than in OA patients. The production of SDF-1 was enhanced in RA FLS by MIF stimulation. Such effect of MIF was blocked by the inhibitors of NF-kappaB. Concentrations of SDF-1 in the serum and SF were higher in RA patients than in OA patients and healthy control. SDF-1 and MIF was overexpressed in RA FLS, and MIF could up-regulate the production of SDF-1 in RA FLS via NF-kappaB- mediated pathways. CONCLUSION: These results suggest that an inhibition of interaction between MIF from T cells and SDF-1 of FLS may provide a new therapeutic approach in the treatment of RA.