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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

A2BR agonist-treated dendritic cells acquired increased ability to stimulate γδ and Th17 autoreactive T cells.A) Splenic APCs isolated from A2BR agonist-treated, immunized B6 mice have stronger ability stimulating γδ, and Th17 autoreactive T cells. Responder T cells were isolated from immunized B6 mice 13 days post immunization. After a 3-day co-incubation of T cells and splenic APCs, the activated T cells were separated by Ficoll gradient centrifugation and staining for γδ T cells or Th17 cells. B) A2BR agonist-treated BMDCs acquired increased stimulating activity to stimulate γδ, and Th17 autoreactive T cells. BMDCs were cultured from bone marrow cells of immunized B6 mice. After a 5 day co-culture of in vivo primed responder T cells with A2BR agonist-treated and-untreated BMDCs in the presence of immunizing peptide, the number of γδ T cells and IL-17+ T cells among activated T cells were examined (B) and the IL-17 and IFN-γ amounts in 48 h-stimulated culture supernatants were compared (C). **p< 0.01.
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pone.0132348.g006: A2BR agonist-treated dendritic cells acquired increased ability to stimulate γδ and Th17 autoreactive T cells.A) Splenic APCs isolated from A2BR agonist-treated, immunized B6 mice have stronger ability stimulating γδ, and Th17 autoreactive T cells. Responder T cells were isolated from immunized B6 mice 13 days post immunization. After a 3-day co-incubation of T cells and splenic APCs, the activated T cells were separated by Ficoll gradient centrifugation and staining for γδ T cells or Th17 cells. B) A2BR agonist-treated BMDCs acquired increased stimulating activity to stimulate γδ, and Th17 autoreactive T cells. BMDCs were cultured from bone marrow cells of immunized B6 mice. After a 5 day co-culture of in vivo primed responder T cells with A2BR agonist-treated and-untreated BMDCs in the presence of immunizing peptide, the number of γδ T cells and IL-17+ T cells among activated T cells were examined (B) and the IL-17 and IFN-γ amounts in 48 h-stimulated culture supernatants were compared (C). **p< 0.01.

Mentions: To determine how BAY 60–6583 enhanced the Th17 response without being able to direct activate γδ T cells, we examined whether this effect was mediated indirectly by stimulation of DCs. We therefore tested whether DCs from BAY 60-6583-treated mice had a greater stimulating activity on γδ T cells. First, we compared the stimulatory effect of splenic APCs from BAY 60-6583- or vehicle-treated immunized B6 mice using total splenic CD3+ T cells from immunized B6 mice as responder T cells to splenic APCs. After 3 days’ exposure in vitro to the splenic APCs, the numbers of γδ T cells among the responder T cells were assessed by FACS staining. As shown in Fig 6A, incubation with splenic APCs from BAY 60-6583-treated mice resulted in a higher percentage of γδ T cells in the CD3 T cells and the percentage of IL-17+ T cells in the αβ T cells than incubation with APCs from untreated mice. In addition, we prepared bone marrow dendritic cells (BMDCs) from bone marrow cells of immunized B6 mice by culturing them in GM-CSF-containing medium and examined whether cultured BMDCs showed a similar ability to activate γδ T cells and Th17 autoreactive T cells. Our results showed that, after in vitro exposure to BAY 60–6583, BMDCs showed a significantly increased ability to stimulate IL-17+ γδ T cells, as assessed by IL-17 production (Fig 6C) and, as shown in Fig 6B, to increase the percentage of γδ T cells in the CD3 T cells (upper panels) and the percentage of IL-17+ T cells in the αβ T cells (lower panels).


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)

A2BR agonist-treated dendritic cells acquired increased ability to stimulate γδ and Th17 autoreactive T cells.A) Splenic APCs isolated from A2BR agonist-treated, immunized B6 mice have stronger ability stimulating γδ, and Th17 autoreactive T cells. Responder T cells were isolated from immunized B6 mice 13 days post immunization. After a 3-day co-incubation of T cells and splenic APCs, the activated T cells were separated by Ficoll gradient centrifugation and staining for γδ T cells or Th17 cells. B) A2BR agonist-treated BMDCs acquired increased stimulating activity to stimulate γδ, and Th17 autoreactive T cells. BMDCs were cultured from bone marrow cells of immunized B6 mice. After a 5 day co-culture of in vivo primed responder T cells with A2BR agonist-treated and-untreated BMDCs in the presence of immunizing peptide, the number of γδ T cells and IL-17+ T cells among activated T cells were examined (B) and the IL-17 and IFN-γ amounts in 48 h-stimulated culture supernatants were compared (C). **p< 0.01.
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pone.0132348.g006: A2BR agonist-treated dendritic cells acquired increased ability to stimulate γδ and Th17 autoreactive T cells.A) Splenic APCs isolated from A2BR agonist-treated, immunized B6 mice have stronger ability stimulating γδ, and Th17 autoreactive T cells. Responder T cells were isolated from immunized B6 mice 13 days post immunization. After a 3-day co-incubation of T cells and splenic APCs, the activated T cells were separated by Ficoll gradient centrifugation and staining for γδ T cells or Th17 cells. B) A2BR agonist-treated BMDCs acquired increased stimulating activity to stimulate γδ, and Th17 autoreactive T cells. BMDCs were cultured from bone marrow cells of immunized B6 mice. After a 5 day co-culture of in vivo primed responder T cells with A2BR agonist-treated and-untreated BMDCs in the presence of immunizing peptide, the number of γδ T cells and IL-17+ T cells among activated T cells were examined (B) and the IL-17 and IFN-γ amounts in 48 h-stimulated culture supernatants were compared (C). **p< 0.01.
Mentions: To determine how BAY 60–6583 enhanced the Th17 response without being able to direct activate γδ T cells, we examined whether this effect was mediated indirectly by stimulation of DCs. We therefore tested whether DCs from BAY 60-6583-treated mice had a greater stimulating activity on γδ T cells. First, we compared the stimulatory effect of splenic APCs from BAY 60-6583- or vehicle-treated immunized B6 mice using total splenic CD3+ T cells from immunized B6 mice as responder T cells to splenic APCs. After 3 days’ exposure in vitro to the splenic APCs, the numbers of γδ T cells among the responder T cells were assessed by FACS staining. As shown in Fig 6A, incubation with splenic APCs from BAY 60-6583-treated mice resulted in a higher percentage of γδ T cells in the CD3 T cells and the percentage of IL-17+ T cells in the αβ T cells than incubation with APCs from untreated mice. In addition, we prepared bone marrow dendritic cells (BMDCs) from bone marrow cells of immunized B6 mice by culturing them in GM-CSF-containing medium and examined whether cultured BMDCs showed a similar ability to activate γδ T cells and Th17 autoreactive T cells. Our results showed that, after in vitro exposure to BAY 60–6583, BMDCs showed a significantly increased ability to stimulate IL-17+ γδ T cells, as assessed by IL-17 production (Fig 6C) and, as shown in Fig 6B, to increase the percentage of γδ T cells in the CD3 T cells (upper panels) and the percentage of IL-17+ T cells in the αβ T cells (lower panels).

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