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Blockade of tumor necrosis factor in collagen-induced arthritis reveals a novel immunoregulatory pathway for Th1 and Th17 cells.

Notley CA, Inglis JJ, Alzabin S, McCann FE, McNamee KE, Williams RO - J. Exp. Med. (2008)

Bottom Line: IL-17 is implicated in the pathogenesis of rheumatoid arthritis (RA) and has previously been shown to be induced by tumor necrosis factor (TNF) in vitro.TNF blockade using TNFR-Fc fusion protein or anti-TNF monoclonal antibody reduced arthritis severity but, unexpectedly, expanded populations of Th1 and Th17 cells, which were shown by adoptive transfer to be pathogenic.Treatment of macrophages with rTNF also inhibited p40 production in vitro.

View Article: PubMed Central - PubMed

Affiliation: Kennedy Institute of Rheumatology Division, Imperial College London, London, W6 8LH, England, UK.

ABSTRACT
IL-17 is implicated in the pathogenesis of rheumatoid arthritis (RA) and has previously been shown to be induced by tumor necrosis factor (TNF) in vitro. The aim of this study was to assess the impact of TNF inhibition on IL-17 production in collagen-induced arthritis, a model of RA. TNF blockade using TNFR-Fc fusion protein or anti-TNF monoclonal antibody reduced arthritis severity but, unexpectedly, expanded populations of Th1 and Th17 cells, which were shown by adoptive transfer to be pathogenic. Th1 and Th17 cell populations were also expanded in collagen-immunized TNFR p55(-/-) but not p75(-/-) mice. The expression of IL-12/IL-23 p40 was up-regulated in lymph nodes (LN) from p55(-/-) mice, and the expansion of Th1/Th17 cells was abrogated by blockade of p40. Treatment of macrophages with rTNF also inhibited p40 production in vitro. These findings indicate that at least one of the ways in which TNF regulates Th1/Th17 responses in arthritis is by down-regulating the expression of p40. Finally, although TNF blockade increased numbers of Th1 and Th17 cells in LN, it inhibited their accumulation in the joint, thereby providing an explanation for the paradox that anti-TNF therapy ameliorates arthritis despite increasing numbers of pathogenic T cells.

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TNFα inhibits expression of IL-12/IL-23 p40. Thioglycolate-elicited macrophages were cultured in the presence or absence of 30 or 100 ng/ml TNFα for 8 h and then stimulated for a further 18 h with 1 ng/ml LPS. (A–C) Levels of p40, IL-1β, and IL-6 protein were determined in the culture supernatants by ELISA. (D) Relative levels of p40 mRNA from WT, p55 TNFR−/−, and p75 TNFR−/− LN cells 14 d after immunization were determined by real time PCR. Histograms show mean ± SEM (n = 4). *, P < 0.05; **, P < 0.01; ***, P < 0.001.
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fig3: TNFα inhibits expression of IL-12/IL-23 p40. Thioglycolate-elicited macrophages were cultured in the presence or absence of 30 or 100 ng/ml TNFα for 8 h and then stimulated for a further 18 h with 1 ng/ml LPS. (A–C) Levels of p40, IL-1β, and IL-6 protein were determined in the culture supernatants by ELISA. (D) Relative levels of p40 mRNA from WT, p55 TNFR−/−, and p75 TNFR−/− LN cells 14 d after immunization were determined by real time PCR. Histograms show mean ± SEM (n = 4). *, P < 0.05; **, P < 0.01; ***, P < 0.001.

Mentions: We next sought to identify the mechanism by which TNFα reduces Th17 and Th1 cell activity. IL-12 and IL-23 share a common subunit, p40. Dimerization of p40 with p35 forms IL-12, which is involved in the differentiation of Th1 cells, whereas dimerization of p40 with p19 forms IL-23, which has an important role in the generation and/or survival of Th17 cells. Hence, one possible explanation for our findings is that TNFα conditions myeloid cells toward reduced p40 expression, and we set out to address this question using thioglycolate-elicited macrophages stimulated with LPS in vitro. Pretreatment of macrophages before LPS stimulation with 30 or 100 ng/ml of TNFα produced a dose-dependent reduction of p40 upon subsequent stimulation with LPS (Fig. 3). The maximum inhibition of p40 production by LPS-stimulated macrophages was ∼50%, and the failure to obtain greater suppression was attributed to the fact that LPS alone would inevitably produce significant quantities of TNFα. TNFα pretreatment also suppressed IL-6 production at 100 ng/ml, but not at 30 ng/ml, but had no effect on IL-1β production at either dose (Fig. 3). This shows that the effect of TNFα on cytokine production was selective and did not cause global suppression of cellular activity.


Blockade of tumor necrosis factor in collagen-induced arthritis reveals a novel immunoregulatory pathway for Th1 and Th17 cells.

Notley CA, Inglis JJ, Alzabin S, McCann FE, McNamee KE, Williams RO - J. Exp. Med. (2008)

TNFα inhibits expression of IL-12/IL-23 p40. Thioglycolate-elicited macrophages were cultured in the presence or absence of 30 or 100 ng/ml TNFα for 8 h and then stimulated for a further 18 h with 1 ng/ml LPS. (A–C) Levels of p40, IL-1β, and IL-6 protein were determined in the culture supernatants by ELISA. (D) Relative levels of p40 mRNA from WT, p55 TNFR−/−, and p75 TNFR−/− LN cells 14 d after immunization were determined by real time PCR. Histograms show mean ± SEM (n = 4). *, P < 0.05; **, P < 0.01; ***, P < 0.001.
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fig3: TNFα inhibits expression of IL-12/IL-23 p40. Thioglycolate-elicited macrophages were cultured in the presence or absence of 30 or 100 ng/ml TNFα for 8 h and then stimulated for a further 18 h with 1 ng/ml LPS. (A–C) Levels of p40, IL-1β, and IL-6 protein were determined in the culture supernatants by ELISA. (D) Relative levels of p40 mRNA from WT, p55 TNFR−/−, and p75 TNFR−/− LN cells 14 d after immunization were determined by real time PCR. Histograms show mean ± SEM (n = 4). *, P < 0.05; **, P < 0.01; ***, P < 0.001.
Mentions: We next sought to identify the mechanism by which TNFα reduces Th17 and Th1 cell activity. IL-12 and IL-23 share a common subunit, p40. Dimerization of p40 with p35 forms IL-12, which is involved in the differentiation of Th1 cells, whereas dimerization of p40 with p19 forms IL-23, which has an important role in the generation and/or survival of Th17 cells. Hence, one possible explanation for our findings is that TNFα conditions myeloid cells toward reduced p40 expression, and we set out to address this question using thioglycolate-elicited macrophages stimulated with LPS in vitro. Pretreatment of macrophages before LPS stimulation with 30 or 100 ng/ml of TNFα produced a dose-dependent reduction of p40 upon subsequent stimulation with LPS (Fig. 3). The maximum inhibition of p40 production by LPS-stimulated macrophages was ∼50%, and the failure to obtain greater suppression was attributed to the fact that LPS alone would inevitably produce significant quantities of TNFα. TNFα pretreatment also suppressed IL-6 production at 100 ng/ml, but not at 30 ng/ml, but had no effect on IL-1β production at either dose (Fig. 3). This shows that the effect of TNFα on cytokine production was selective and did not cause global suppression of cellular activity.

Bottom Line: IL-17 is implicated in the pathogenesis of rheumatoid arthritis (RA) and has previously been shown to be induced by tumor necrosis factor (TNF) in vitro.TNF blockade using TNFR-Fc fusion protein or anti-TNF monoclonal antibody reduced arthritis severity but, unexpectedly, expanded populations of Th1 and Th17 cells, which were shown by adoptive transfer to be pathogenic.Treatment of macrophages with rTNF also inhibited p40 production in vitro.

View Article: PubMed Central - PubMed

Affiliation: Kennedy Institute of Rheumatology Division, Imperial College London, London, W6 8LH, England, UK.

ABSTRACT
IL-17 is implicated in the pathogenesis of rheumatoid arthritis (RA) and has previously been shown to be induced by tumor necrosis factor (TNF) in vitro. The aim of this study was to assess the impact of TNF inhibition on IL-17 production in collagen-induced arthritis, a model of RA. TNF blockade using TNFR-Fc fusion protein or anti-TNF monoclonal antibody reduced arthritis severity but, unexpectedly, expanded populations of Th1 and Th17 cells, which were shown by adoptive transfer to be pathogenic. Th1 and Th17 cell populations were also expanded in collagen-immunized TNFR p55(-/-) but not p75(-/-) mice. The expression of IL-12/IL-23 p40 was up-regulated in lymph nodes (LN) from p55(-/-) mice, and the expansion of Th1/Th17 cells was abrogated by blockade of p40. Treatment of macrophages with rTNF also inhibited p40 production in vitro. These findings indicate that at least one of the ways in which TNF regulates Th1/Th17 responses in arthritis is by down-regulating the expression of p40. Finally, although TNF blockade increased numbers of Th1 and Th17 cells in LN, it inhibited their accumulation in the joint, thereby providing an explanation for the paradox that anti-TNF therapy ameliorates arthritis despite increasing numbers of pathogenic T cells.

Show MeSH
Related in: MedlinePlus