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Resistin enhances the expansion of regulatory T cells through modulation of dendritic cells.

Son YM, Ahn SM, Kim GR, Moon YS, Kim SH, Park YM, Lee WK, Min TS, Han SH, Yun CH - BMC Immunol. (2010)

Bottom Line: Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs.At the same time, resistin had no direct effect on the induction of FoxP3 in CD4+ T cells, suggesting an indirect role through other cells type(s).Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 151-921, Republic of Korea.

ABSTRACT

Background: Resistin, a member of adipokine family, is known to be involved in the modulation of immune responses including inflammatory activity. Interestingly, resistin is secreted by adipocytes in mice and rats whereas it is secreted by leukocytes in humans. However, the mechanism behind the effect of resistin on the expansion of regulatory T cells (Tregs) remains poorly understood. Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs.

Results: Both protein and mRNA expression of FoxP3, a representative marker of Tregs, increased in a dose-dependent manner when peripheral blood mononuclear cells were treated with resistin. At the same time, resistin had no direct effect on the induction of FoxP3 in CD4+ T cells, suggesting an indirect role through other cells type(s). Since DCs are an important player in the differentiation of T cells, we focused on the role of DCs in the modulation of Tregs by resistin. Resistin suppressed the expression of interferon regulatory factor (IRF)-1 and its target cytokines, IL-6, IL-23p19 and IL-12p40, in DCs. Furthermore, FoxP3 expression is increased in CD4+ T cells when co-cultured with DCs and concomitantly treated with resistin.

Conclusion: Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

Show MeSH
The number of Tregs increased when co-cultured with DCs and concomitantly treated with resistin. CD4+ T cells or CD4+ CD25- T cells and DCs were co-cultured with 500 ng/ml of resistin for 4 days. The cells were then incubated with anti-human CD2 and CD3 antibodies for an additional 3 days. (A) At the end of the incubation period, total RNA was isolated and subjected to RT-PCR to measure mRNA expression of CTLA-4, FoxP3 and TGF-β. (B) After the staining of the cells with anti-human CD25-APC and -FoxP3-PE antibodies, CD25+FoxP3+ Tregs were analyzed by flow cytometry. (C) After the staining with anti-human CD25-APC antibody, CD25+ T cells were isolated using anti-APC magnetic beads. The isolated CD25+ T cells and CD4+ CD25- naïve T cells labeled with CFSE were co-cultured with DCs and stimulated with anti-human CD2 and CD3 antibodies for 5 days. Cell proliferation was measured by flow cytometry. The value in each panel indicates the percentage of CD25+ FoxP3+ Tregs.
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Figure 2: The number of Tregs increased when co-cultured with DCs and concomitantly treated with resistin. CD4+ T cells or CD4+ CD25- T cells and DCs were co-cultured with 500 ng/ml of resistin for 4 days. The cells were then incubated with anti-human CD2 and CD3 antibodies for an additional 3 days. (A) At the end of the incubation period, total RNA was isolated and subjected to RT-PCR to measure mRNA expression of CTLA-4, FoxP3 and TGF-β. (B) After the staining of the cells with anti-human CD25-APC and -FoxP3-PE antibodies, CD25+FoxP3+ Tregs were analyzed by flow cytometry. (C) After the staining with anti-human CD25-APC antibody, CD25+ T cells were isolated using anti-APC magnetic beads. The isolated CD25+ T cells and CD4+ CD25- naïve T cells labeled with CFSE were co-cultured with DCs and stimulated with anti-human CD2 and CD3 antibodies for 5 days. Cell proliferation was measured by flow cytometry. The value in each panel indicates the percentage of CD25+ FoxP3+ Tregs.

Mentions: The primary role of DCs is to interact with T cells and trigger adaptive immune responses, but DCs are also involved in the differentiation of Tregs [12]. Therefore, to further examine whether resistin-treated DCs are involved in the regulation of Tregs, CD4+ T cells and DCs were co-cultured and concomitantly treated with resistin. mRNA expression levels of TGF-β, CTLA-4 and FoxP3, representative markers of Tregs, were subsequently measured. The expression of TGF-β, CTLA-4 and FoxP3 was greater in cells treated with resistin than those without resistin treatment (figure 2A). This finding was further confirmed by changes of CD4+ CD25+ FoxP3+ Tregs using flow cytometry. As shown in figure 2B (upper panel), CD4+ CD25+ FoxP3+ cells were significantly (P < 0.05) higher in cells treated with resistin than those without treatment (additional file 1). And, to confirm whether the increased number of Tregs were induced from naïve CD4+ T cells or expanded from Tregs, CD4+ CD25- naïve T cells were co-cultured and concomitantly treated with resistin. The result showed that CD25+ FoxP3+ Tregs were expanded from Tregs but were merely induced from CD4+ CD25- naïve T cells when co-cultured with resistin-treated DCs (figure 2B bottom panel). Finally, CD4+ CD25+ T cells were isolated after co-culture of T cells and DCs concomitantly treated with/without resistin in order to examine their functional capacity to suppress the activity of effector T cells. CD4+ CD25- T cells labeled with CFSE were co-cultured with CD4+ CD25+ T cells and stimulated with anti-human CD2 and CD3 antibodies. When compared with a proliferation of CD4+ CD25- naïve T cells only, the CD4+ CD25+ Tregs induced by DCs treated with resistin suppressed the proliferation of CD4+ CD25- naïve T cells similar to CD4+ CD25+ T cells induced by DCs without resistin (figure 2C). These results suggest that resistin modulates the functionality of DCs to enhance the expansion of CD4+ CD25+ FoxP3+ Tregs.


Resistin enhances the expansion of regulatory T cells through modulation of dendritic cells.

Son YM, Ahn SM, Kim GR, Moon YS, Kim SH, Park YM, Lee WK, Min TS, Han SH, Yun CH - BMC Immunol. (2010)

The number of Tregs increased when co-cultured with DCs and concomitantly treated with resistin. CD4+ T cells or CD4+ CD25- T cells and DCs were co-cultured with 500 ng/ml of resistin for 4 days. The cells were then incubated with anti-human CD2 and CD3 antibodies for an additional 3 days. (A) At the end of the incubation period, total RNA was isolated and subjected to RT-PCR to measure mRNA expression of CTLA-4, FoxP3 and TGF-β. (B) After the staining of the cells with anti-human CD25-APC and -FoxP3-PE antibodies, CD25+FoxP3+ Tregs were analyzed by flow cytometry. (C) After the staining with anti-human CD25-APC antibody, CD25+ T cells were isolated using anti-APC magnetic beads. The isolated CD25+ T cells and CD4+ CD25- naïve T cells labeled with CFSE were co-cultured with DCs and stimulated with anti-human CD2 and CD3 antibodies for 5 days. Cell proliferation was measured by flow cytometry. The value in each panel indicates the percentage of CD25+ FoxP3+ Tregs.
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Related In: Results  -  Collection

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Figure 2: The number of Tregs increased when co-cultured with DCs and concomitantly treated with resistin. CD4+ T cells or CD4+ CD25- T cells and DCs were co-cultured with 500 ng/ml of resistin for 4 days. The cells were then incubated with anti-human CD2 and CD3 antibodies for an additional 3 days. (A) At the end of the incubation period, total RNA was isolated and subjected to RT-PCR to measure mRNA expression of CTLA-4, FoxP3 and TGF-β. (B) After the staining of the cells with anti-human CD25-APC and -FoxP3-PE antibodies, CD25+FoxP3+ Tregs were analyzed by flow cytometry. (C) After the staining with anti-human CD25-APC antibody, CD25+ T cells were isolated using anti-APC magnetic beads. The isolated CD25+ T cells and CD4+ CD25- naïve T cells labeled with CFSE were co-cultured with DCs and stimulated with anti-human CD2 and CD3 antibodies for 5 days. Cell proliferation was measured by flow cytometry. The value in each panel indicates the percentage of CD25+ FoxP3+ Tregs.
Mentions: The primary role of DCs is to interact with T cells and trigger adaptive immune responses, but DCs are also involved in the differentiation of Tregs [12]. Therefore, to further examine whether resistin-treated DCs are involved in the regulation of Tregs, CD4+ T cells and DCs were co-cultured and concomitantly treated with resistin. mRNA expression levels of TGF-β, CTLA-4 and FoxP3, representative markers of Tregs, were subsequently measured. The expression of TGF-β, CTLA-4 and FoxP3 was greater in cells treated with resistin than those without resistin treatment (figure 2A). This finding was further confirmed by changes of CD4+ CD25+ FoxP3+ Tregs using flow cytometry. As shown in figure 2B (upper panel), CD4+ CD25+ FoxP3+ cells were significantly (P < 0.05) higher in cells treated with resistin than those without treatment (additional file 1). And, to confirm whether the increased number of Tregs were induced from naïve CD4+ T cells or expanded from Tregs, CD4+ CD25- naïve T cells were co-cultured and concomitantly treated with resistin. The result showed that CD25+ FoxP3+ Tregs were expanded from Tregs but were merely induced from CD4+ CD25- naïve T cells when co-cultured with resistin-treated DCs (figure 2B bottom panel). Finally, CD4+ CD25+ T cells were isolated after co-culture of T cells and DCs concomitantly treated with/without resistin in order to examine their functional capacity to suppress the activity of effector T cells. CD4+ CD25- T cells labeled with CFSE were co-cultured with CD4+ CD25+ T cells and stimulated with anti-human CD2 and CD3 antibodies. When compared with a proliferation of CD4+ CD25- naïve T cells only, the CD4+ CD25+ Tregs induced by DCs treated with resistin suppressed the proliferation of CD4+ CD25- naïve T cells similar to CD4+ CD25+ T cells induced by DCs without resistin (figure 2C). These results suggest that resistin modulates the functionality of DCs to enhance the expansion of CD4+ CD25+ FoxP3+ Tregs.

Bottom Line: Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs.At the same time, resistin had no direct effect on the induction of FoxP3 in CD4+ T cells, suggesting an indirect role through other cells type(s).Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Gwanak-gu, Seoul 151-921, Republic of Korea.

ABSTRACT

Background: Resistin, a member of adipokine family, is known to be involved in the modulation of immune responses including inflammatory activity. Interestingly, resistin is secreted by adipocytes in mice and rats whereas it is secreted by leukocytes in humans. However, the mechanism behind the effect of resistin on the expansion of regulatory T cells (Tregs) remains poorly understood. Therefore, we examined regulatory effect of resistin on the induction and cellular modification of Tregs.

Results: Both protein and mRNA expression of FoxP3, a representative marker of Tregs, increased in a dose-dependent manner when peripheral blood mononuclear cells were treated with resistin. At the same time, resistin had no direct effect on the induction of FoxP3 in CD4+ T cells, suggesting an indirect role through other cells type(s). Since DCs are an important player in the differentiation of T cells, we focused on the role of DCs in the modulation of Tregs by resistin. Resistin suppressed the expression of interferon regulatory factor (IRF)-1 and its target cytokines, IL-6, IL-23p19 and IL-12p40, in DCs. Furthermore, FoxP3 expression is increased in CD4+ T cells when co-cultured with DCs and concomitantly treated with resistin.

Conclusion: Our results suggest that resistin induces expansion of functional Tregs only when co-cultured with DCs.

Show MeSH