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Galectin-9 controls CD40 signaling through a Tim-3 independent mechanism and redirects the cytokine profile of pathogenic T cells in autoimmunity.

Vaitaitis GM, Wagner DH - PLoS ONE (2012)

Bottom Line: Galectins interact with carbohydrates on proteins to effect such signaling alterations.Studying autoimmune prone NOD and non-autoimmune BALB/c mice, here we reveal that in-vivo CD40 signals alter the glycosylation status of non-autoimmune derived CD4 T cells to resemble that of autoimmune derived CD4 T cells.Interestingly, galectin-9, at lower concentrations, alters the surface expression of CD3, CD4, and TCR, regulating access to those molecules and thereby redirects the inflammatory cytokine phenotype and CD3 induced proliferation of autoimmune CD4(lo)CD40(+) T cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine and Webb-Waring Center, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
While it has long been understood that CD40 plays a critical role in the etiology of autoimmunity, glycobiology is emerging as an important contributor. CD40 signaling is also gaining further interest in transplantation and cancer therapies. Work on CD40 signaling has focused on signaling outcomes and blocking of its ligand, CD154, while little is known about the actual receptor itself and its control. We demonstrated that CD40 is in fact several receptors occurring as constellations of differentially glycosylated forms of the protein that can sometimes form hybrid receptors with other proteins. An enticing area of autoimmunity is differential glycosylation of immune molecules leading to altered signaling. Galectins interact with carbohydrates on proteins to effect such signaling alterations. Studying autoimmune prone NOD and non-autoimmune BALB/c mice, here we reveal that in-vivo CD40 signals alter the glycosylation status of non-autoimmune derived CD4 T cells to resemble that of autoimmune derived CD4 T cells. Galectin-9 interacts with CD40 and, at higher concentrations, prevents CD40 induced proliferative responses of CD4(lo)CD40(+) effector T cells and induces cell death through a Tim-3 independent mechanism. Interestingly, galectin-9, at lower concentrations, alters the surface expression of CD3, CD4, and TCR, regulating access to those molecules and thereby redirects the inflammatory cytokine phenotype and CD3 induced proliferation of autoimmune CD4(lo)CD40(+) T cells. Understanding the dynamics of the CD40 receptor(s) and the impact of glycosylation status in immunity will gain insight into how to maintain useful CD40 signals while shutting down detrimental ones.

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Related in: MedlinePlus

CD3 and CD40 co-stimulation increases production of some cytokines.Data represented in this figure were part of experiments done in Figure 6 and can therefore be directly compared to Figure 6. Cells were sorted as in Figure 6 and were CD3- and CD40-stimulated in the absence/presence of indicated concentrations of galectin-9 (gal-9; µg/ml) for 3 days then cytokines were measured. Bar graphs depict means with SEM. Asterisks denote significant differences determined by one-way Anova; * – P between 0.01 and 0.05; ** – P <0.01. Measurements were done on four individual mice of different ages.
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pone-0038708-g007: CD3 and CD40 co-stimulation increases production of some cytokines.Data represented in this figure were part of experiments done in Figure 6 and can therefore be directly compared to Figure 6. Cells were sorted as in Figure 6 and were CD3- and CD40-stimulated in the absence/presence of indicated concentrations of galectin-9 (gal-9; µg/ml) for 3 days then cytokines were measured. Bar graphs depict means with SEM. Asterisks denote significant differences determined by one-way Anova; * – P between 0.01 and 0.05; ** – P <0.01. Measurements were done on four individual mice of different ages.

Mentions: CD40 has been demonstrated to be a co-stimulatory molecule on T cells, comparable in its function to CD28 [32]. Therefore we determined the cytokine production by NOD CD4loCD40+ T cells in response to simultaneous CD3 and CD40 stimulation. IFNγ and IL-2 were induced to significantly higher levels during co-stimulation compared to single treatment (Fig. 7; note scale changes compared to Fig. 6). The other cytokine levels were unaffected by the co-stimulation. Interestingly, while IFNγ production more than doubled, galectin-9 addition no longer impacted the level of production. IL-2 production was doubled by the co-stimulation and remained sensitive to galectin-9 which increased the induced levels (Fig. 7; note scale changes compared to Fig. 6).


Galectin-9 controls CD40 signaling through a Tim-3 independent mechanism and redirects the cytokine profile of pathogenic T cells in autoimmunity.

Vaitaitis GM, Wagner DH - PLoS ONE (2012)

CD3 and CD40 co-stimulation increases production of some cytokines.Data represented in this figure were part of experiments done in Figure 6 and can therefore be directly compared to Figure 6. Cells were sorted as in Figure 6 and were CD3- and CD40-stimulated in the absence/presence of indicated concentrations of galectin-9 (gal-9; µg/ml) for 3 days then cytokines were measured. Bar graphs depict means with SEM. Asterisks denote significant differences determined by one-way Anova; * – P between 0.01 and 0.05; ** – P <0.01. Measurements were done on four individual mice of different ages.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369903&req=5

pone-0038708-g007: CD3 and CD40 co-stimulation increases production of some cytokines.Data represented in this figure were part of experiments done in Figure 6 and can therefore be directly compared to Figure 6. Cells were sorted as in Figure 6 and were CD3- and CD40-stimulated in the absence/presence of indicated concentrations of galectin-9 (gal-9; µg/ml) for 3 days then cytokines were measured. Bar graphs depict means with SEM. Asterisks denote significant differences determined by one-way Anova; * – P between 0.01 and 0.05; ** – P <0.01. Measurements were done on four individual mice of different ages.
Mentions: CD40 has been demonstrated to be a co-stimulatory molecule on T cells, comparable in its function to CD28 [32]. Therefore we determined the cytokine production by NOD CD4loCD40+ T cells in response to simultaneous CD3 and CD40 stimulation. IFNγ and IL-2 were induced to significantly higher levels during co-stimulation compared to single treatment (Fig. 7; note scale changes compared to Fig. 6). The other cytokine levels were unaffected by the co-stimulation. Interestingly, while IFNγ production more than doubled, galectin-9 addition no longer impacted the level of production. IL-2 production was doubled by the co-stimulation and remained sensitive to galectin-9 which increased the induced levels (Fig. 7; note scale changes compared to Fig. 6).

Bottom Line: Galectins interact with carbohydrates on proteins to effect such signaling alterations.Studying autoimmune prone NOD and non-autoimmune BALB/c mice, here we reveal that in-vivo CD40 signals alter the glycosylation status of non-autoimmune derived CD4 T cells to resemble that of autoimmune derived CD4 T cells.Interestingly, galectin-9, at lower concentrations, alters the surface expression of CD3, CD4, and TCR, regulating access to those molecules and thereby redirects the inflammatory cytokine phenotype and CD3 induced proliferation of autoimmune CD4(lo)CD40(+) T cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine and Webb-Waring Center, University of Colorado Denver, Aurora, Colorado, United States of America.

ABSTRACT
While it has long been understood that CD40 plays a critical role in the etiology of autoimmunity, glycobiology is emerging as an important contributor. CD40 signaling is also gaining further interest in transplantation and cancer therapies. Work on CD40 signaling has focused on signaling outcomes and blocking of its ligand, CD154, while little is known about the actual receptor itself and its control. We demonstrated that CD40 is in fact several receptors occurring as constellations of differentially glycosylated forms of the protein that can sometimes form hybrid receptors with other proteins. An enticing area of autoimmunity is differential glycosylation of immune molecules leading to altered signaling. Galectins interact with carbohydrates on proteins to effect such signaling alterations. Studying autoimmune prone NOD and non-autoimmune BALB/c mice, here we reveal that in-vivo CD40 signals alter the glycosylation status of non-autoimmune derived CD4 T cells to resemble that of autoimmune derived CD4 T cells. Galectin-9 interacts with CD40 and, at higher concentrations, prevents CD40 induced proliferative responses of CD4(lo)CD40(+) effector T cells and induces cell death through a Tim-3 independent mechanism. Interestingly, galectin-9, at lower concentrations, alters the surface expression of CD3, CD4, and TCR, regulating access to those molecules and thereby redirects the inflammatory cytokine phenotype and CD3 induced proliferation of autoimmune CD4(lo)CD40(+) T cells. Understanding the dynamics of the CD40 receptor(s) and the impact of glycosylation status in immunity will gain insight into how to maintain useful CD40 signals while shutting down detrimental ones.

Show MeSH
Related in: MedlinePlus