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Regulatory T Cells Resist Cyclosporine-Induced Cell Death via CD44-Mediated Signaling Pathways.

Ruppert SM, Falk BA, Long SA, Bollyky PL - Int J Cell Biol (2015)

Bottom Line: We found that CD44 cross-linking promoted Foxp3 expression and Treg viability in the setting of CSA treatment.This effect was IL-2 independent but could be suppressed using sc-355979, an inhibitor of Stat5-phosphorylation.Moreover, we found that inhibition of HA synthesis impairs Treg homeostasis but that this effect could be overcome with exogenous IL-2 or CD44-cross-linking.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases and Geographic Medicine, Department of Medicine, 300 Pasteur Drive, Stanford University School of Medicine, Stanford, CA 94305-5107, USA.

ABSTRACT
Cyclosporine A (CSA) is an immunosuppressive agent that specifically targets T cells and also increases the percentage of pro-tolerogenic CD4+Foxp3+ regulatory T cells (Treg) through unknown mechanisms. We previously reported that CD44, a receptor for the extracellular matrix glycosaminoglycan hyaluronan (HA), promotes Treg stability in IL-2-low environments. Here, we asked whether CD44 signaling also promotes Treg resistance to CSA. We found that CD44 cross-linking promoted Foxp3 expression and Treg viability in the setting of CSA treatment. This effect was IL-2 independent but could be suppressed using sc-355979, an inhibitor of Stat5-phosphorylation. Moreover, we found that inhibition of HA synthesis impairs Treg homeostasis but that this effect could be overcome with exogenous IL-2 or CD44-cross-linking. Together, these data support a model whereby CD44 cross-linking by HA promotes IL-2-independent Foxp3 expression and Treg survival in the face of CSA.

No MeSH data available.


Related in: MedlinePlus

CD44 cross-linking promotes Foxp3 expression in an IL-2-independent manner. (a) Fold Increase (FI) in GFP/FoxP3 MFI for Treg activated with anti-CD3 and anti-CD28 Ab alone or in conjunction with plate-bound anti-CD44 Ab with or without anti-IL-2 Ab (Anti-IL-2), recombinant CD25 (rCD25), or IL-2 (n = 7). (b) Representative histograms demonstrating GFP/Foxp3 expression by Treg isolated from GFP/Foxp3 knock-in mice on a conventional B6 background mice or on a CD25−/− background (B6 GFP/Foxp3.CD25−/− mice) following 3 days of culture with anti-CD3 and anti-28 alone or in conjunction with plate-bound anti-CD44. (c) Representative histograms illustrating GFP/FoxP3 expression of Treg following 3 days of culture with anti-CD3 and anti-CD28 alone, or in conjunction with plate-bound CD44 Ab, and with or without varying doses of IL-2. Data are representative of two experiments.
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fig3: CD44 cross-linking promotes Foxp3 expression in an IL-2-independent manner. (a) Fold Increase (FI) in GFP/FoxP3 MFI for Treg activated with anti-CD3 and anti-CD28 Ab alone or in conjunction with plate-bound anti-CD44 Ab with or without anti-IL-2 Ab (Anti-IL-2), recombinant CD25 (rCD25), or IL-2 (n = 7). (b) Representative histograms demonstrating GFP/Foxp3 expression by Treg isolated from GFP/Foxp3 knock-in mice on a conventional B6 background mice or on a CD25−/− background (B6 GFP/Foxp3.CD25−/− mice) following 3 days of culture with anti-CD3 and anti-28 alone or in conjunction with plate-bound anti-CD44. (c) Representative histograms illustrating GFP/FoxP3 expression of Treg following 3 days of culture with anti-CD3 and anti-CD28 alone, or in conjunction with plate-bound CD44 Ab, and with or without varying doses of IL-2. Data are representative of two experiments.

Mentions: We first neutralized any IL-2 that might be produced in our Treg activation cultures by adding recombinant CD25 (rCD25), the high affinity IL-2 receptor, or antibodies directed at IL-2. However, these reagents did not completely negate the beneficial effect of CD44 cross-linking on Foxp3 expression (Figure 3(a)).


Regulatory T Cells Resist Cyclosporine-Induced Cell Death via CD44-Mediated Signaling Pathways.

Ruppert SM, Falk BA, Long SA, Bollyky PL - Int J Cell Biol (2015)

CD44 cross-linking promotes Foxp3 expression in an IL-2-independent manner. (a) Fold Increase (FI) in GFP/FoxP3 MFI for Treg activated with anti-CD3 and anti-CD28 Ab alone or in conjunction with plate-bound anti-CD44 Ab with or without anti-IL-2 Ab (Anti-IL-2), recombinant CD25 (rCD25), or IL-2 (n = 7). (b) Representative histograms demonstrating GFP/Foxp3 expression by Treg isolated from GFP/Foxp3 knock-in mice on a conventional B6 background mice or on a CD25−/− background (B6 GFP/Foxp3.CD25−/− mice) following 3 days of culture with anti-CD3 and anti-28 alone or in conjunction with plate-bound anti-CD44. (c) Representative histograms illustrating GFP/FoxP3 expression of Treg following 3 days of culture with anti-CD3 and anti-CD28 alone, or in conjunction with plate-bound CD44 Ab, and with or without varying doses of IL-2. Data are representative of two experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig3: CD44 cross-linking promotes Foxp3 expression in an IL-2-independent manner. (a) Fold Increase (FI) in GFP/FoxP3 MFI for Treg activated with anti-CD3 and anti-CD28 Ab alone or in conjunction with plate-bound anti-CD44 Ab with or without anti-IL-2 Ab (Anti-IL-2), recombinant CD25 (rCD25), or IL-2 (n = 7). (b) Representative histograms demonstrating GFP/Foxp3 expression by Treg isolated from GFP/Foxp3 knock-in mice on a conventional B6 background mice or on a CD25−/− background (B6 GFP/Foxp3.CD25−/− mice) following 3 days of culture with anti-CD3 and anti-28 alone or in conjunction with plate-bound anti-CD44. (c) Representative histograms illustrating GFP/FoxP3 expression of Treg following 3 days of culture with anti-CD3 and anti-CD28 alone, or in conjunction with plate-bound CD44 Ab, and with or without varying doses of IL-2. Data are representative of two experiments.
Mentions: We first neutralized any IL-2 that might be produced in our Treg activation cultures by adding recombinant CD25 (rCD25), the high affinity IL-2 receptor, or antibodies directed at IL-2. However, these reagents did not completely negate the beneficial effect of CD44 cross-linking on Foxp3 expression (Figure 3(a)).

Bottom Line: We found that CD44 cross-linking promoted Foxp3 expression and Treg viability in the setting of CSA treatment.This effect was IL-2 independent but could be suppressed using sc-355979, an inhibitor of Stat5-phosphorylation.Moreover, we found that inhibition of HA synthesis impairs Treg homeostasis but that this effect could be overcome with exogenous IL-2 or CD44-cross-linking.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases and Geographic Medicine, Department of Medicine, 300 Pasteur Drive, Stanford University School of Medicine, Stanford, CA 94305-5107, USA.

ABSTRACT
Cyclosporine A (CSA) is an immunosuppressive agent that specifically targets T cells and also increases the percentage of pro-tolerogenic CD4+Foxp3+ regulatory T cells (Treg) through unknown mechanisms. We previously reported that CD44, a receptor for the extracellular matrix glycosaminoglycan hyaluronan (HA), promotes Treg stability in IL-2-low environments. Here, we asked whether CD44 signaling also promotes Treg resistance to CSA. We found that CD44 cross-linking promoted Foxp3 expression and Treg viability in the setting of CSA treatment. This effect was IL-2 independent but could be suppressed using sc-355979, an inhibitor of Stat5-phosphorylation. Moreover, we found that inhibition of HA synthesis impairs Treg homeostasis but that this effect could be overcome with exogenous IL-2 or CD44-cross-linking. Together, these data support a model whereby CD44 cross-linking by HA promotes IL-2-independent Foxp3 expression and Treg survival in the face of CSA.

No MeSH data available.


Related in: MedlinePlus