Feedback Control of Cyclooxygenase-2 Expression by Prostaglandin E2 in Rheumatoid Synoviocytes

Th17 cells are critically involved in autoimmune disease induction and severity. Recently, we showed that Th17 cells from patients with rheumatoid arthritis (RA) directly induced a proinflammatory loop upon interaction with RA synovial fibroblasts (RASF), including increased autocrine IL-17A production. To unravel the mechanism driving this IL-17A production, we obtained primary CD4+CD45RO+CCR6+ (Th17) cells and CD4+CD45RO+CCR6− (CCR6−) T cells from RA patients or healthy individuals and cocultured these with RASF. IL-1β, IL-6, IL-23p19, and cyclooxygenase (COX)-2 expression and PGE2 production in Th17–RASF cultures were higher than in CCR6− T cell–RASF cultures. Cytokine neutralization showed that IL-1β and IL-6, but not IL-23, contributed to autocrine IL-17A induction. Importantly, treatment with celecoxib, a COX-2 inhibitor, resulted in significantly lower PGE2 and IL-17A, but not IFN-γ, production. Combined celecoxib and TNF-α blockade more effectively suppressed the proinflammatory loop than did single treatment, as shown by lower IL-6, IL-8, matrix metalloproteinase-1 and matrix metalloproteinase-3 production. These findings show a critical role for the COX-2/PGE2 pathway in driving Th17-mediated synovial inflammation in an IL-23– and monocyte-independent manner. Therefore, it would be important to control PGE2 in chronic inflammation in RA and potentially other Th17-mediated autoimmune disorders.

Section: Discussionmentioning

confidence: 57%

Synovial Fibroblasts Directly Induce Th17 Pathogenicity via the Cyclooxygenase/Prostaglandin E2 Pathway, Independent of IL-23

Paulissen

Hamburg

Davelaar

et al. 2013

“…The isolation of the FLS from the synovial tissues was performed as described previously (12). The FLS, from passages 3 through 7, were seeded in 24-well plates (Nunc) at 3 ϫ 10 4 cells/well or in a 100-mm culture dish at 5 ϫ 10 5 cells in DMEM supplemented with 10% FCS (Invitrogen Life Technologies) and cultivated at 37°C for 24 h. To eliminate the influence of FCS on calcineurin activity, the cells were washed with DMEM and then incubated again in serum-free DMEM supplemented with insulin-transferrin-selenium A (ITSA; Invitrogen Life Technologies) for 48 h, until the medium was replaced with fresh DMEM/ITSA.…”

Section: Isolation and Culture Of Fibroblast-like Synoviocytes (Fls)mentioning

confidence: 99%

“…The amounts of IL-6, IL-10, and IL-17 released into the culture supernatants were measured by ELISA, as described previously (12). The concentrations of MMP-1 (Amersham Biosciences), MMP-2 (R&D Systems), MMP-3 (Amersham Biosciences), and MMP-9 (R&D Systems) were also measured by ELISA, according to the manufacturers' instructions.…”

Section: Elisa For Il-6 Il-10 Il-17 and Mmpmentioning

confidence: 99%

Calcineurin Is Expressed and Plays a Critical Role in Inflammatory Arthritis

Yoo¹,

Park²,

Park³

et al. 2006

Self Cite

Calcineurin is a calcium-activated phosphatase to mediate lymphocyte activation and neuron signaling, but its role in inflammatory arthritis remains largely unknown. In this study, we demonstrate that calcineurin was highly expressed in the lining layer, infiltrating leukocytes, and endothelial cells of rheumatoid synovium. The basal expression levels of calcineurin were higher in the cultured synoviocytes of rheumatoid arthritis patients than those of osteoarthritis patients. The calcineurin activity in the synoviocytes was increased by the stimulation with proinflammatory cytokines such as IL-1β and TNF-α. Moreover, rheumatoid arthritis synoviocytes had an enlarged intracellular Ca2+ store and showed a higher degree of [Ca2+]i release for calcineurin activity than osteoarthritis synoviocytes when stimulated with either TNF-α or phorbol myristate acetate. IL-10, an anti-inflammatory cytokine, failed to increase the Ca2+ and calcineurin activity. The targeted inhibition of calcineurin by the overexpression of calcineurin-binding protein 1, a natural calcineurin antagonist, inhibited the production of IL-6 and matrix metalloproteinase-2 by rheumatoid synoviocytes in a similar manner to the calcineurin inhibitor, cyclosporin A. Moreover, the abundant calcineurin expression was found in the invading pannus in the joints of mice with collagen-induced arthritis. In these mice, calcineurin activity in the cultured synovial and lymph node cells correlated well with the severity of arthritis, but which was suppressed by cyclosporin A treatment. Taken together, our data suggest that the abnormal activation of Ca2+ and calcineurin in the synoviocytes may contribute to the pathogenesis of chronic arthritis and thus provide a potential target for controlling inflammatory arthritis.

“…For example, using a gel EMSA, NF-B was found to be one of the major signal molecules to mediate IL-15-induced cyclooxygenase-2 up-regulation in rheumatoid synoviocytes (46). IL-15 was also found to inhibit spontaneous apoptosis in human eosinophils via autocrine production of GM-CSF and NF-B activation (17).…”

Section: (15) a Synergism Between Il-21 And Il-15 Has Been Recently mentioning

confidence: 99%

Differential Effects of IL-15 and IL-21 in Myeloid (CD11b+) and Lymphoid (CD11b−) Bone Marrow Cells

Pelletier

Girard

2006

IL-15 has been found to activate NF-κB in various types of cells. However, the role of this transcription factor in IL-15- and IL-21-stimulated murine bone marrow (BM) cells is unclear. In this study, we demonstrated that both IL-15 and IL-21 are capable of delaying BM cell factor deprivation-induced apoptosis, but only IL-15 induced their proliferation. Following separation of BM cells into myeloid (CD11b+) and lymphoid (CD11b−) cell populations, we found that IL-15, but not IL-21, significantly induced proliferation in both cell populations. Both cytokines significantly delayed apoptosis, but only in CD11b− BM cells. IL-15Rα, CD122 (IL-2/15Rβ), and common γ-chains (CD132) were expressed in both populations, whereas IL-21Rα was expressed only in CD11b− BM cells. In addition, we demonstrated that IL-15-induced BM cell proliferation was significantly inhibited in NF-κBp50−/− mice when compared with littermate controls. The ability of IL-15 and IL-21 to delay BM cell apoptosis was slightly inhibited in NF-κBp50−/− mice, whereas the antiapoptotic effect of LPS was markedly reversed. We conclude that IL-15, but not IL-21, induces BM cell proliferation and that both cytokines delay BM cell apoptosis. These biological activities were preferentially observed in CD11b− BM cells. Using NF-κBp50−/− mice, we demonstrated for the first time that NF-κB plays a greater role in IL-15-induced cell proliferation than in IL-15- and IL-21-induced suppression of apoptosis.