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An A2B Adenosine Receptor Agonist Promotes Th17 Autoimmune Responses in Experimental Autoimmune Uveitis (EAU) via Dendritic Cell Activation.

Chen M, Liang D, Zuo A, Shao H, Kaplan HJ, Sun D - PLoS ONE (2015)

Bottom Line: We have recently reported that, although adenosine receptor (AR) agonists have a suppressive effect on Th1 autoreactive T cells, their effect on Th17 autoreactive T cells and γδ T cells is stimulatory and this effect is mainly mediated via A2A adenosine receptors (A2ARs).In the present study, we showed that exposure of DCs to A2BR agonist facilitated γδ T cell activation, leading to augmented Th17 responses and progressive EAU development.Our results further support our previous finding that AR agonists have distinct effects on Th1 and Th17 autoimmune responses.

View Article: PubMed Central - PubMed

Affiliation: Doheny Eye Institute and Department of Ophthalmology, University of California, Los Angeles, CA90033, United States of America.

ABSTRACT
We have recently reported that, although adenosine receptor (AR) agonists have a suppressive effect on Th1 autoreactive T cells, their effect on Th17 autoreactive T cells and γδ T cells is stimulatory and this effect is mainly mediated via A2A adenosine receptors (A2ARs). In this study, we further demonstrate that treatment of C57BL/6 (B6) mice with a selective A2B adenosine receptor (A2BR) agonist greatly enhanced the development of experimental autoimmune uveitis (EAU), whereas treatment with an A2BR antagonist significantly ameliorated severity of EAU. The A2BR agonist-treated mice showed augmented Th17, but not Th1, responses. Mechanistic studies showed that the A2BR agonist-induced enhancement of the Th17 response was significantly lower when TCR-δ-/- mice received the same treatment and that transfer of γδ T cells into TCR-δ-/- mice partially restored this effect. We also showed that dendritic cells (DCs) from A2BR agonist-treated mice showed a significantly increased ability to activate γδ T cells and Th17 autoreactive T cells. Thus, our previous studies have shown that, in EAU, activated γδ T cells possess greatly increased ability to enhance Th17 autoimmune responses. In the present study, we showed that exposure of DCs to A2BR agonist facilitated γδ T cell activation, leading to augmented Th17 responses and progressive EAU development. Our results further support our previous finding that AR agonists have distinct effects on Th1 and Th17 autoimmune responses.

No MeSH data available.


Related in: MedlinePlus

BMDCs incubated in vitro with the A2BR agonist produce increased amounts of IL-23 and IL-6 and have enhanced ability enhancing Th17 response.A) BMDCs cultured from immunized B6 mice were further cultured for 48h in the absence or presence of A2BR agonist (100 ng/ml), then IL-1, IL-12, IL-23 and IL-6 levels in the culture supernatants were measured by ELISA. B) Neither TLR2 ligand nor A2BR agonist along induced increased MHC II and CD86 expression on BMDCs, but a synergistic effect did. Cultured BMDCs were incubated with or without TLR2 ligand (Pam3CSK, 10μg/ml) and in the presence or absence of the A2BR agonist (100 ng/ml). 24h later, the expression of MHC II and CD86 on BMDCs was assessed by FACS after staining with FITC-anti-mouse MHC II or FITC-anti-mouse CD86 antibodies, respectively. C) The 48h supernatants of T cell-BMDC co-cultures described in Fig 7B were tested for IL-17 amount. **p<0.01. D) After an in vitro treatment with vehicle (control) or A2BR agonist for 24 h, the supernatants of BMDCs were taken and added to co-cultures of in vivo primed CD3+ responder T cells and splenic APCs, in the presence of the immunizing peptide and under Th17 polarizing conditions. After 5 days, proliferating T cells were stained intracellularly for IL-17.
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pone.0132348.g007: BMDCs incubated in vitro with the A2BR agonist produce increased amounts of IL-23 and IL-6 and have enhanced ability enhancing Th17 response.A) BMDCs cultured from immunized B6 mice were further cultured for 48h in the absence or presence of A2BR agonist (100 ng/ml), then IL-1, IL-12, IL-23 and IL-6 levels in the culture supernatants were measured by ELISA. B) Neither TLR2 ligand nor A2BR agonist along induced increased MHC II and CD86 expression on BMDCs, but a synergistic effect did. Cultured BMDCs were incubated with or without TLR2 ligand (Pam3CSK, 10μg/ml) and in the presence or absence of the A2BR agonist (100 ng/ml). 24h later, the expression of MHC II and CD86 on BMDCs was assessed by FACS after staining with FITC-anti-mouse MHC II or FITC-anti-mouse CD86 antibodies, respectively. C) The 48h supernatants of T cell-BMDC co-cultures described in Fig 7B were tested for IL-17 amount. **p<0.01. D) After an in vitro treatment with vehicle (control) or A2BR agonist for 24 h, the supernatants of BMDCs were taken and added to co-cultures of in vivo primed CD3+ responder T cells and splenic APCs, in the presence of the immunizing peptide and under Th17 polarizing conditions. After 5 days, proliferating T cells were stained intracellularly for IL-17.

Mentions: Since DC-produced cytokines, such as IL-1, IL-6 and IL-23, are important promoters of the activation of Th17 autoreactive T cells [40–43], we examined whether the increased γδ T cell-stimulating effect of BMDCs from BAY 60-6583-treated immunized mice correlated with altered production of cytokines by BMDCs. When BMDCs from immunized B6 mice were incubated in vitro with BAY 60–6583 or vehicle, in the presence or absence of a Toll-like receptor 2 (TLR2) ligand (Pam3CSK), then levels of IL-1, IL-6, IL-12, and IL-23 in the culture supernatants were measured. Our results showed that treatment of TLR ligand induced BMDCs to produce all the four cytokines tested and BAY 60–6583 was unable to induce cytokine production from the BMDCs by itself. The levels of IL-1, IL-6, and IL-23 were markedly increased, but the IL-12 was significantly decreased in culture supernatants of BMDCs incubated with BAY 60–6583 and TLR ligand (Fig 7A). Neither TLR ligand along nor BAY 60–6583 induced increased expression of MHC class II and CD86 molecules on BMDCs, whereas when added together an enhanced expression was noticed (Fig 7B). In addition, when CD3+ T cells isolated from immunized B6 mice were stimulated by the immunizing antigen and APCs in the presence of supernatants from these BAY 60-6583-treated or vehicle-treated BMDCs, the former resulted in increased IL-17 secretion (Fig 7D) and an increased percentage of IL-17+ αβ T cells (Fig 7C).


An A2B Adenosine Receptor Agonist Promotes Th17 Autoimmune Responses in Experimental Autoimmune Uveitis (EAU) via Dendritic Cell Activation.

Chen M, Liang D, Zuo A, Shao H, Kaplan HJ, Sun D - PLoS ONE (2015)

BMDCs incubated in vitro with the A2BR agonist produce increased amounts of IL-23 and IL-6 and have enhanced ability enhancing Th17 response.A) BMDCs cultured from immunized B6 mice were further cultured for 48h in the absence or presence of A2BR agonist (100 ng/ml), then IL-1, IL-12, IL-23 and IL-6 levels in the culture supernatants were measured by ELISA. B) Neither TLR2 ligand nor A2BR agonist along induced increased MHC II and CD86 expression on BMDCs, but a synergistic effect did. Cultured BMDCs were incubated with or without TLR2 ligand (Pam3CSK, 10μg/ml) and in the presence or absence of the A2BR agonist (100 ng/ml). 24h later, the expression of MHC II and CD86 on BMDCs was assessed by FACS after staining with FITC-anti-mouse MHC II or FITC-anti-mouse CD86 antibodies, respectively. C) The 48h supernatants of T cell-BMDC co-cultures described in Fig 7B were tested for IL-17 amount. **p<0.01. D) After an in vitro treatment with vehicle (control) or A2BR agonist for 24 h, the supernatants of BMDCs were taken and added to co-cultures of in vivo primed CD3+ responder T cells and splenic APCs, in the presence of the immunizing peptide and under Th17 polarizing conditions. After 5 days, proliferating T cells were stained intracellularly for IL-17.
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Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4492970&req=5

pone.0132348.g007: BMDCs incubated in vitro with the A2BR agonist produce increased amounts of IL-23 and IL-6 and have enhanced ability enhancing Th17 response.A) BMDCs cultured from immunized B6 mice were further cultured for 48h in the absence or presence of A2BR agonist (100 ng/ml), then IL-1, IL-12, IL-23 and IL-6 levels in the culture supernatants were measured by ELISA. B) Neither TLR2 ligand nor A2BR agonist along induced increased MHC II and CD86 expression on BMDCs, but a synergistic effect did. Cultured BMDCs were incubated with or without TLR2 ligand (Pam3CSK, 10μg/ml) and in the presence or absence of the A2BR agonist (100 ng/ml). 24h later, the expression of MHC II and CD86 on BMDCs was assessed by FACS after staining with FITC-anti-mouse MHC II or FITC-anti-mouse CD86 antibodies, respectively. C) The 48h supernatants of T cell-BMDC co-cultures described in Fig 7B were tested for IL-17 amount. **p<0.01. D) After an in vitro treatment with vehicle (control) or A2BR agonist for 24 h, the supernatants of BMDCs were taken and added to co-cultures of in vivo primed CD3+ responder T cells and splenic APCs, in the presence of the immunizing peptide and under Th17 polarizing conditions. After 5 days, proliferating T cells were stained intracellularly for IL-17.
Mentions: Since DC-produced cytokines, such as IL-1, IL-6 and IL-23, are important promoters of the activation of Th17 autoreactive T cells [40–43], we examined whether the increased γδ T cell-stimulating effect of BMDCs from BAY 60-6583-treated immunized mice correlated with altered production of cytokines by BMDCs. When BMDCs from immunized B6 mice were incubated in vitro with BAY 60–6583 or vehicle, in the presence or absence of a Toll-like receptor 2 (TLR2) ligand (Pam3CSK), then levels of IL-1, IL-6, IL-12, and IL-23 in the culture supernatants were measured. Our results showed that treatment of TLR ligand induced BMDCs to produce all the four cytokines tested and BAY 60–6583 was unable to induce cytokine production from the BMDCs by itself. The levels of IL-1, IL-6, and IL-23 were markedly increased, but the IL-12 was significantly decreased in culture supernatants of BMDCs incubated with BAY 60–6583 and TLR ligand (Fig 7A). Neither TLR ligand along nor BAY 60–6583 induced increased expression of MHC class II and CD86 molecules on BMDCs, whereas when added together an enhanced expression was noticed (Fig 7B). In addition, when CD3+ T cells isolated from immunized B6 mice were stimulated by the immunizing antigen and APCs in the presence of supernatants from these BAY 60-6583-treated or vehicle-treated BMDCs, the former resulted in increased IL-17 secretion (Fig 7D) and an increased percentage of IL-17+ αβ T cells (Fig 7C).

Bottom Line: We have recently reported that, although adenosine receptor (AR) agonists have a suppressive effect on Th1 autoreactive T cells, their effect on Th17 autoreactive T cells and γδ T cells is stimulatory and this effect is mainly mediated via A2A adenosine receptors (A2ARs).In the present study, we showed that exposure of DCs to A2BR agonist facilitated γδ T cell activation, leading to augmented Th17 responses and progressive EAU development.Our results further support our previous finding that AR agonists have distinct effects on Th1 and Th17 autoimmune responses.

View Article: PubMed Central - PubMed

Affiliation: Doheny Eye Institute and Department of Ophthalmology, University of California, Los Angeles, CA90033, United States of America.

ABSTRACT
We have recently reported that, although adenosine receptor (AR) agonists have a suppressive effect on Th1 autoreactive T cells, their effect on Th17 autoreactive T cells and γδ T cells is stimulatory and this effect is mainly mediated via A2A adenosine receptors (A2ARs). In this study, we further demonstrate that treatment of C57BL/6 (B6) mice with a selective A2B adenosine receptor (A2BR) agonist greatly enhanced the development of experimental autoimmune uveitis (EAU), whereas treatment with an A2BR antagonist significantly ameliorated severity of EAU. The A2BR agonist-treated mice showed augmented Th17, but not Th1, responses. Mechanistic studies showed that the A2BR agonist-induced enhancement of the Th17 response was significantly lower when TCR-δ-/- mice received the same treatment and that transfer of γδ T cells into TCR-δ-/- mice partially restored this effect. We also showed that dendritic cells (DCs) from A2BR agonist-treated mice showed a significantly increased ability to activate γδ T cells and Th17 autoreactive T cells. Thus, our previous studies have shown that, in EAU, activated γδ T cells possess greatly increased ability to enhance Th17 autoimmune responses. In the present study, we showed that exposure of DCs to A2BR agonist facilitated γδ T cell activation, leading to augmented Th17 responses and progressive EAU development. Our results further support our previous finding that AR agonists have distinct effects on Th1 and Th17 autoimmune responses.

No MeSH data available.


Related in: MedlinePlus