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Transcription factors RUNX1 and RUNX3 in the induction and suppressive function of Foxp3+ inducible regulatory T cells.

Klunker S, Chong MM, Mantel PY, Palomares O, Bassin C, Ziegler M, Rückert B, Meiler F, Akdis M, Littman DR, Akdis CA - J. Exp. Med. (2009)

Bottom Line: Circulating human CD4(+) CD25(high) CD127(-) T reg cells significantly expressed higher levels of RUNX3, FOXP3, and TGF-beta mRNA compared with CD4(+)CD25(-) cells.Furthermore, FOXP3 and RUNX3 were colocalized in human tonsil T reg cells.These data demonstrate Runx transcription factors as a molecular link in TGF-beta-induced Foxp3 expression in iT reg cell differentiation and function.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swiss Institute of Allergy and Asthma Research Davos, University of Zurich, CH-7270 Davos-Platz, Switzerland.

ABSTRACT
Forkhead box P3 (FOXP3)(+)CD4(+)CD25(+) inducible regulatory T (iT reg) cells play an important role in immune tolerance and homeostasis. In this study, we show that the transforming growth factor-beta (TGF-beta) induces the expression of the Runt-related transcription factors RUNX1 and RUNX3 in CD4(+) T cells. This induction seems to be a prerequisite for the binding of RUNX1 and RUNX3 to three putative RUNX binding sites in the FOXP3 promoter. Inactivation of the gene encoding RUNX cofactor core-binding factor-beta (CBFbeta) in mice and small interfering RNA (siRNA)-mediated suppression of RUNX1 and RUNX3 in human T cells resulted in reduced expression of Foxp3. The in vivo conversion of naive CD4(+) T cells into Foxp3(+) iT reg cells was significantly decreased in adoptively transferred Cbfb(F/F) CD4-cre naive T cells into Rag2(-/-) mice. Both RUNX1 and RUNX3 siRNA silenced human T reg cells and Cbfb(F/F) CD4-cre mouse T reg cells showed diminished suppressive function in vitro. Circulating human CD4(+) CD25(high) CD127(-) T reg cells significantly expressed higher levels of RUNX3, FOXP3, and TGF-beta mRNA compared with CD4(+)CD25(-) cells. Furthermore, FOXP3 and RUNX3 were colocalized in human tonsil T reg cells. These data demonstrate Runx transcription factors as a molecular link in TGF-beta-induced Foxp3 expression in iT reg cell differentiation and function.

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Diminished capacity of Cbfb-deficient CD4-cre mice T cells in the generation of Foxp3+ CD4+ T cells. (A) FACS-purified naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice were activated in vitro with anti-CD3/28 mAb, 50 U/ml IL-2, ± 10 nM retinoic acid (RA), and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA + ionomycin, and then analyzed for intracellular Foxp3 and IFN-γ expression. One of five experiments is shown. (B) Naive CD4+ T cells from Cbfb CD4-cre or control mice (harboring a Foxp3-IRES-GFP allele) were adoptively transferred into Rag-deficient mice (5 × 106 cells per transfer). 6 wk later, TCRβ+CD4+ cells from the spleen, mesenteric lymph node (MLN), and lamina propria of the small intestine (LP) were analyzed for Foxp3-GFP expression. Results from one of four CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice with same findings are shown. The data from four sets of mice is shown in C. Statistical analysis was performed with Mann-Whitney U test. *, P < 0.05 between groups.
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fig5: Diminished capacity of Cbfb-deficient CD4-cre mice T cells in the generation of Foxp3+ CD4+ T cells. (A) FACS-purified naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice were activated in vitro with anti-CD3/28 mAb, 50 U/ml IL-2, ± 10 nM retinoic acid (RA), and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA + ionomycin, and then analyzed for intracellular Foxp3 and IFN-γ expression. One of five experiments is shown. (B) Naive CD4+ T cells from Cbfb CD4-cre or control mice (harboring a Foxp3-IRES-GFP allele) were adoptively transferred into Rag-deficient mice (5 × 106 cells per transfer). 6 wk later, TCRβ+CD4+ cells from the spleen, mesenteric lymph node (MLN), and lamina propria of the small intestine (LP) were analyzed for Foxp3-GFP expression. Results from one of four CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice with same findings are shown. The data from four sets of mice is shown in C. Statistical analysis was performed with Mann-Whitney U test. *, P < 0.05 between groups.

Mentions: CBFβ, a common cofactor of all RUNX proteins, stabilizes and increases the binding of the runt domain to target DNA sequences. To target all Runx proteins that might be involved in the induction of Foxp3, we used mice in which loxP-flanked Cbfb alleles were inactivated in T cells through expression of a CD4-cre transgene. Retinoic acid and TGF-β synergize in the induction of Foxp3 in naive T cells (Kang et al., 2007). To investigate whether Runx-mediated induction of Foxp3 is dependent on the expression of CBFβ, naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+CD4-cre mice were stimulated with anti-CD3/28 mAbs, retinoic acid, and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA and ionomycin and analyzed for intracellular Foxp3 and IFN-γ expression. TGF-β induced Foxp3 in CbfbF/+CD4-cre cells in a dose dependent manner, and this was significantly reduced in CbfbF/F CD4-cre cells. Retinoic acid enhanced Foxp3 expression even in 20 pg/ml of TGF-β and more than 95% of the CD4+ T cells from CbfbF/+ CD4-cre mice became Foxp3+ in 100 and 500 pg/ml TGF-β doses. The induction of Foxp3 was again significantly lower in CbfbF/F CD4-cre CD4+ T cells even in the presence of retinoic acid, demonstrating that deficiency in Runx binding to DNA affects the TGF-β induction of Foxp3 in T reg cells (Fig. 5 A). There was no difference in the induction of Foxp3 when endogenous IL-4 and IFN-γ were neutralized (Fig. S6).


Transcription factors RUNX1 and RUNX3 in the induction and suppressive function of Foxp3+ inducible regulatory T cells.

Klunker S, Chong MM, Mantel PY, Palomares O, Bassin C, Ziegler M, Rückert B, Meiler F, Akdis M, Littman DR, Akdis CA - J. Exp. Med. (2009)

Diminished capacity of Cbfb-deficient CD4-cre mice T cells in the generation of Foxp3+ CD4+ T cells. (A) FACS-purified naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice were activated in vitro with anti-CD3/28 mAb, 50 U/ml IL-2, ± 10 nM retinoic acid (RA), and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA + ionomycin, and then analyzed for intracellular Foxp3 and IFN-γ expression. One of five experiments is shown. (B) Naive CD4+ T cells from Cbfb CD4-cre or control mice (harboring a Foxp3-IRES-GFP allele) were adoptively transferred into Rag-deficient mice (5 × 106 cells per transfer). 6 wk later, TCRβ+CD4+ cells from the spleen, mesenteric lymph node (MLN), and lamina propria of the small intestine (LP) were analyzed for Foxp3-GFP expression. Results from one of four CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice with same findings are shown. The data from four sets of mice is shown in C. Statistical analysis was performed with Mann-Whitney U test. *, P < 0.05 between groups.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2806624&req=5

fig5: Diminished capacity of Cbfb-deficient CD4-cre mice T cells in the generation of Foxp3+ CD4+ T cells. (A) FACS-purified naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice were activated in vitro with anti-CD3/28 mAb, 50 U/ml IL-2, ± 10 nM retinoic acid (RA), and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA + ionomycin, and then analyzed for intracellular Foxp3 and IFN-γ expression. One of five experiments is shown. (B) Naive CD4+ T cells from Cbfb CD4-cre or control mice (harboring a Foxp3-IRES-GFP allele) were adoptively transferred into Rag-deficient mice (5 × 106 cells per transfer). 6 wk later, TCRβ+CD4+ cells from the spleen, mesenteric lymph node (MLN), and lamina propria of the small intestine (LP) were analyzed for Foxp3-GFP expression. Results from one of four CbfbF/F CD4-cre and control CbfbF/+ CD4-cre mice with same findings are shown. The data from four sets of mice is shown in C. Statistical analysis was performed with Mann-Whitney U test. *, P < 0.05 between groups.
Mentions: CBFβ, a common cofactor of all RUNX proteins, stabilizes and increases the binding of the runt domain to target DNA sequences. To target all Runx proteins that might be involved in the induction of Foxp3, we used mice in which loxP-flanked Cbfb alleles were inactivated in T cells through expression of a CD4-cre transgene. Retinoic acid and TGF-β synergize in the induction of Foxp3 in naive T cells (Kang et al., 2007). To investigate whether Runx-mediated induction of Foxp3 is dependent on the expression of CBFβ, naive CD4+ CD8− T cells from CbfbF/F CD4-cre and control CbfbF/+CD4-cre mice were stimulated with anti-CD3/28 mAbs, retinoic acid, and increasing concentrations of TGF-β. After 3 d in culture, the cells were restimulated with PMA and ionomycin and analyzed for intracellular Foxp3 and IFN-γ expression. TGF-β induced Foxp3 in CbfbF/+CD4-cre cells in a dose dependent manner, and this was significantly reduced in CbfbF/F CD4-cre cells. Retinoic acid enhanced Foxp3 expression even in 20 pg/ml of TGF-β and more than 95% of the CD4+ T cells from CbfbF/+ CD4-cre mice became Foxp3+ in 100 and 500 pg/ml TGF-β doses. The induction of Foxp3 was again significantly lower in CbfbF/F CD4-cre CD4+ T cells even in the presence of retinoic acid, demonstrating that deficiency in Runx binding to DNA affects the TGF-β induction of Foxp3 in T reg cells (Fig. 5 A). There was no difference in the induction of Foxp3 when endogenous IL-4 and IFN-γ were neutralized (Fig. S6).

Bottom Line: Circulating human CD4(+) CD25(high) CD127(-) T reg cells significantly expressed higher levels of RUNX3, FOXP3, and TGF-beta mRNA compared with CD4(+)CD25(-) cells.Furthermore, FOXP3 and RUNX3 were colocalized in human tonsil T reg cells.These data demonstrate Runx transcription factors as a molecular link in TGF-beta-induced Foxp3 expression in iT reg cell differentiation and function.

View Article: PubMed Central - HTML - PubMed

Affiliation: Swiss Institute of Allergy and Asthma Research Davos, University of Zurich, CH-7270 Davos-Platz, Switzerland.

ABSTRACT
Forkhead box P3 (FOXP3)(+)CD4(+)CD25(+) inducible regulatory T (iT reg) cells play an important role in immune tolerance and homeostasis. In this study, we show that the transforming growth factor-beta (TGF-beta) induces the expression of the Runt-related transcription factors RUNX1 and RUNX3 in CD4(+) T cells. This induction seems to be a prerequisite for the binding of RUNX1 and RUNX3 to three putative RUNX binding sites in the FOXP3 promoter. Inactivation of the gene encoding RUNX cofactor core-binding factor-beta (CBFbeta) in mice and small interfering RNA (siRNA)-mediated suppression of RUNX1 and RUNX3 in human T cells resulted in reduced expression of Foxp3. The in vivo conversion of naive CD4(+) T cells into Foxp3(+) iT reg cells was significantly decreased in adoptively transferred Cbfb(F/F) CD4-cre naive T cells into Rag2(-/-) mice. Both RUNX1 and RUNX3 siRNA silenced human T reg cells and Cbfb(F/F) CD4-cre mouse T reg cells showed diminished suppressive function in vitro. Circulating human CD4(+) CD25(high) CD127(-) T reg cells significantly expressed higher levels of RUNX3, FOXP3, and TGF-beta mRNA compared with CD4(+)CD25(-) cells. Furthermore, FOXP3 and RUNX3 were colocalized in human tonsil T reg cells. These data demonstrate Runx transcription factors as a molecular link in TGF-beta-induced Foxp3 expression in iT reg cell differentiation and function.

Show MeSH
Related in: MedlinePlus