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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

Administration of A2BR antagonist to IFN-γ-/- mice mitigated the severity of induced EAU and the activation of Th17 autoreactive T cells.(A&B). IFN-γ-/- mice were immunized with IRBP1-20/CFA alone or were also injected with an A2BR antagonist (MRS 1754, 2 mg/kg) via i.p., on days 1, 4, 7, and 10 post-immunization. The control mice received an injection of vehicle (diluted DMSO). EAU was scored by fundoscopy. All the mice were euthanized 30 days post-immunization, when the mice were sacrificed and the eye were taken and subjected to pathological examination. C) Surface staining assessing abundancy of γδ T cells among CD3+ splenic cells and CD44+ and CD44- γδ T cells. D). Cytoplasmic staining assessing the percentage of IL-17+ cells among the in vitro antigen-stimulated IRBP-specific T cells, detailed as in Fig 1 legend. E). ELISA results from 48-hour culture supernatants were assessed for IL-17. Data are from one single experiment, which are representative of three independent experiments. **p< 0.01.
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pone.0132348.g002: Administration of A2BR antagonist to IFN-γ-/- mice mitigated the severity of induced EAU and the activation of Th17 autoreactive T cells.(A&B). IFN-γ-/- mice were immunized with IRBP1-20/CFA alone or were also injected with an A2BR antagonist (MRS 1754, 2 mg/kg) via i.p., on days 1, 4, 7, and 10 post-immunization. The control mice received an injection of vehicle (diluted DMSO). EAU was scored by fundoscopy. All the mice were euthanized 30 days post-immunization, when the mice were sacrificed and the eye were taken and subjected to pathological examination. C) Surface staining assessing abundancy of γδ T cells among CD3+ splenic cells and CD44+ and CD44- γδ T cells. D). Cytoplasmic staining assessing the percentage of IL-17+ cells among the in vitro antigen-stimulated IRBP-specific T cells, detailed as in Fig 1 legend. E). ELISA results from 48-hour culture supernatants were assessed for IL-17. Data are from one single experiment, which are representative of three independent experiments. **p< 0.01.

Mentions: We then examined whether an A2BR antagonist would inhibit EAU by suppressing the development of Th17 T cell responses. As the average EAU score induced in vehicle-treated B6 mice was low and in the range of 0.5–1 (Fig 1), we used IFN-γ-/- mice, which develop a stronger Th17 response using the same experimental protocol for EAU induction [37,38]. IFN-γ-/- mice were immunized with a pathogenic dose of IRBP1-20 and were injected i.p. with either vehicle (DMSO) or the A2BR antagonist MRS 1754 (1.0 mg/kg) on days 1, 4, 7, and 10 post-immunization. As shown in Fig 2, the immunized IFN-γ-/- mice treated with MRS 1754 showed a marked reduction in EAU score (Fig 2A) and developed significantly milder ocular inflammation than the vehicle-treated immunized mice (Fig 2B). In addition, as shown in Fig 2C, the number of γδ T cells in MRS 1754-treated mice was decreased compared to that in the vehicle-treated mice (left panels), as was their activation status, shown by expression of the activation marker CD44 (right panels). The number of IL-17+ T cells was also significantly decreased among CD4+ T cells from MRS 1754-treated mice compared to T cells from vehicle-treated mice (Fig 2D) and the culture supernatants of in vitro activated Th17 cells from MRS 1754-treated mice contained significantly lower amounts of IL-17 (Fig 2E).


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)

Administration of A2BR antagonist to IFN-γ-/- mice mitigated the severity of induced EAU and the activation of Th17 autoreactive T cells.(A&B). IFN-γ-/- mice were immunized with IRBP1-20/CFA alone or were also injected with an A2BR antagonist (MRS 1754, 2 mg/kg) via i.p., on days 1, 4, 7, and 10 post-immunization. The control mice received an injection of vehicle (diluted DMSO). EAU was scored by fundoscopy. All the mice were euthanized 30 days post-immunization, when the mice were sacrificed and the eye were taken and subjected to pathological examination. C) Surface staining assessing abundancy of γδ T cells among CD3+ splenic cells and CD44+ and CD44- γδ T cells. D). Cytoplasmic staining assessing the percentage of IL-17+ cells among the in vitro antigen-stimulated IRBP-specific T cells, detailed as in Fig 1 legend. E). ELISA results from 48-hour culture supernatants were assessed for IL-17. Data are from one single experiment, which are representative of three independent experiments. **p< 0.01.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4492970&req=5

pone.0132348.g002: Administration of A2BR antagonist to IFN-γ-/- mice mitigated the severity of induced EAU and the activation of Th17 autoreactive T cells.(A&B). IFN-γ-/- mice were immunized with IRBP1-20/CFA alone or were also injected with an A2BR antagonist (MRS 1754, 2 mg/kg) via i.p., on days 1, 4, 7, and 10 post-immunization. The control mice received an injection of vehicle (diluted DMSO). EAU was scored by fundoscopy. All the mice were euthanized 30 days post-immunization, when the mice were sacrificed and the eye were taken and subjected to pathological examination. C) Surface staining assessing abundancy of γδ T cells among CD3+ splenic cells and CD44+ and CD44- γδ T cells. D). Cytoplasmic staining assessing the percentage of IL-17+ cells among the in vitro antigen-stimulated IRBP-specific T cells, detailed as in Fig 1 legend. E). ELISA results from 48-hour culture supernatants were assessed for IL-17. Data are from one single experiment, which are representative of three independent experiments. **p< 0.01.
Mentions: We then examined whether an A2BR antagonist would inhibit EAU by suppressing the development of Th17 T cell responses. As the average EAU score induced in vehicle-treated B6 mice was low and in the range of 0.5–1 (Fig 1), we used IFN-γ-/- mice, which develop a stronger Th17 response using the same experimental protocol for EAU induction [37,38]. IFN-γ-/- mice were immunized with a pathogenic dose of IRBP1-20 and were injected i.p. with either vehicle (DMSO) or the A2BR antagonist MRS 1754 (1.0 mg/kg) on days 1, 4, 7, and 10 post-immunization. As shown in Fig 2, the immunized IFN-γ-/- mice treated with MRS 1754 showed a marked reduction in EAU score (Fig 2A) and developed significantly milder ocular inflammation than the vehicle-treated immunized mice (Fig 2B). In addition, as shown in Fig 2C, the number of γδ T cells in MRS 1754-treated mice was decreased compared to that in the vehicle-treated mice (left panels), as was their activation status, shown by expression of the activation marker CD44 (right panels). The number of IL-17+ T cells was also significantly decreased among CD4+ T cells from MRS 1754-treated mice compared to T cells from vehicle-treated mice (Fig 2D) and the culture supernatants of in vitro activated Th17 cells from MRS 1754-treated mice contained significantly lower amounts of IL-17 (Fig 2E).

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