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Counter-regulation of T cell effector function by differentially activated p38.

Alam MS, Gaida MM, Ogawa Y, Kolios AG, Lasitschka F, Ashwell JD - J. Exp. Med. (2014)

Bottom Line: Unlike the MAP kinase (MAPK) cascade that phosphorylates p38 on the activation loop, T cell receptor (TCR) signaling results in phosphorylation on Tyr-323 (pY323, alternative pathway).Notably, UVB treatment of human psoriatic lesions reduced skin-infiltrating p38 pY323(+) T cell IRF4 and IL-17 production.Thus, distinct mechanisms of p38 activation converge on NFATc1 with opposing effects on T cell immunity, which may underlie the beneficial effect of phototherapy on psoriasis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Immune Cell Biology, Center for Cancer Research; Dermatology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.

ABSTRACT
Unlike the MAP kinase (MAPK) cascade that phosphorylates p38 on the activation loop, T cell receptor (TCR) signaling results in phosphorylation on Tyr-323 (pY323, alternative pathway). Using mice expressing p38α and p38β with Y323F substitutions, we show that alternatively but not MAPK cascade-activated p38 up-regulates the transcription factors NFATc1 and IRF4, which are required for proliferation and cytokine production. Conversely, activation of p38 with UV or osmotic shock mitigated TCR-mediated activation by phosphorylation and cytoplasmic retention of NFATc1. Notably, UVB treatment of human psoriatic lesions reduced skin-infiltrating p38 pY323(+) T cell IRF4 and IL-17 production. Thus, distinct mechanisms of p38 activation converge on NFATc1 with opposing effects on T cell immunity, which may underlie the beneficial effect of phototherapy on psoriasis.

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DKI mice have a defective Th17 response to infection with C. rodentium. (A) WT and DKI mice were infected with C. rodentium by gavage and at day 11–12 cells in the LP were counted. Each symbol represents one mouse, and the mean ± SEM are shown. Data are pooled from two independent experiments with a total of nine mice per group. (B) At day 11 after infection, CD4+ T cells were purified and the expression of Il17a, Rorc, and Irf4 were determined by real-time PCR. The means ± SD are shown (n = 5 mice per group from two independent experiments). (C) IL-17A expression by LP CD4+ T cells was determined by intracellular staining 4 h after stimulation with PMA and ionomycin (left). The mean percentage ± SD of IL-17A–producing CD4+ T cells is shown (right, n = 5 mice per group). Data are representative of two independent experiments. (D) Histological evaluation of representative H&E-stained slides of the colon from WT and DKI mice on day 11 of infection (n = 9 mice per group from 2 independent experiments). Accumulations of lymphocytes are indicated with black circles in WT or arrowheads in DKI mice (left, bar: 100 µm). The thickness of the mucosa is indicated with a black line (middle, bar: 200 µm). Black arrows indicate goblet cells in the colon mucosa (right, bar: 200 µm). (E) The histopathological parameters were quantitated using a double-blinded visual scoring system as detailed in Materials and methods. Data are pooled from 2 independent experiments with a total of 9 mice per group. *, P < 0.05 (unpaired two-tailed Student’s t test).
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fig2: DKI mice have a defective Th17 response to infection with C. rodentium. (A) WT and DKI mice were infected with C. rodentium by gavage and at day 11–12 cells in the LP were counted. Each symbol represents one mouse, and the mean ± SEM are shown. Data are pooled from two independent experiments with a total of nine mice per group. (B) At day 11 after infection, CD4+ T cells were purified and the expression of Il17a, Rorc, and Irf4 were determined by real-time PCR. The means ± SD are shown (n = 5 mice per group from two independent experiments). (C) IL-17A expression by LP CD4+ T cells was determined by intracellular staining 4 h after stimulation with PMA and ionomycin (left). The mean percentage ± SD of IL-17A–producing CD4+ T cells is shown (right, n = 5 mice per group). Data are representative of two independent experiments. (D) Histological evaluation of representative H&E-stained slides of the colon from WT and DKI mice on day 11 of infection (n = 9 mice per group from 2 independent experiments). Accumulations of lymphocytes are indicated with black circles in WT or arrowheads in DKI mice (left, bar: 100 µm). The thickness of the mucosa is indicated with a black line (middle, bar: 200 µm). Black arrows indicate goblet cells in the colon mucosa (right, bar: 200 µm). (E) The histopathological parameters were quantitated using a double-blinded visual scoring system as detailed in Materials and methods. Data are pooled from 2 independent experiments with a total of 9 mice per group. *, P < 0.05 (unpaired two-tailed Student’s t test).

Mentions: To test the importance of p38 alternative activation in a physiological setting, WT and DKI mice were infected with C. rodentium, for which Th17 cells plays a critical protective role (Curtis and Way, 2009). Mice were analyzed at 11–12 d after infection, which is normally at or near the peak of the response (Johnson and Barthold, 1979). WT mice had more infiltrating lymphocytes in the colonic lamina propria (LP) than DKI mice (Fig. 2 A), and freshly isolated LP CD4+ T cells from DKI mice expressed much lower levels of Rorc and Irf4, transcription factors required for Th17 differentiation, than their WT counterparts (Fig. 2 B). Correspondingly, Il17a mRNA and protein expression was highly impaired in lamina propria CD4+ DKI T cells (Fig. 2, B and C). In agreement with the in vitro analyses, histological examination revealed much greater signs inflammation in the colons of WT compared with DKI mice, with greater lymphocyte infiltration in the LP (Fig. 2 D, left), increased mucosal thickness and hyperplastic and elongated crypts, sometimes with a pseudostratified appearance and obvious increased mitotic activity of enterocytes (Fig. 2 D, middle), as well as marked goblet cell depletion (Fig. 2 D, right). A semiquantitative histopathological analysis of multiple mice confirmed the diminished inflammation in the gut of DKI mice (Fig. 2 E).


Counter-regulation of T cell effector function by differentially activated p38.

Alam MS, Gaida MM, Ogawa Y, Kolios AG, Lasitschka F, Ashwell JD - J. Exp. Med. (2014)

DKI mice have a defective Th17 response to infection with C. rodentium. (A) WT and DKI mice were infected with C. rodentium by gavage and at day 11–12 cells in the LP were counted. Each symbol represents one mouse, and the mean ± SEM are shown. Data are pooled from two independent experiments with a total of nine mice per group. (B) At day 11 after infection, CD4+ T cells were purified and the expression of Il17a, Rorc, and Irf4 were determined by real-time PCR. The means ± SD are shown (n = 5 mice per group from two independent experiments). (C) IL-17A expression by LP CD4+ T cells was determined by intracellular staining 4 h after stimulation with PMA and ionomycin (left). The mean percentage ± SD of IL-17A–producing CD4+ T cells is shown (right, n = 5 mice per group). Data are representative of two independent experiments. (D) Histological evaluation of representative H&E-stained slides of the colon from WT and DKI mice on day 11 of infection (n = 9 mice per group from 2 independent experiments). Accumulations of lymphocytes are indicated with black circles in WT or arrowheads in DKI mice (left, bar: 100 µm). The thickness of the mucosa is indicated with a black line (middle, bar: 200 µm). Black arrows indicate goblet cells in the colon mucosa (right, bar: 200 µm). (E) The histopathological parameters were quantitated using a double-blinded visual scoring system as detailed in Materials and methods. Data are pooled from 2 independent experiments with a total of 9 mice per group. *, P < 0.05 (unpaired two-tailed Student’s t test).
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4042639&req=5

fig2: DKI mice have a defective Th17 response to infection with C. rodentium. (A) WT and DKI mice were infected with C. rodentium by gavage and at day 11–12 cells in the LP were counted. Each symbol represents one mouse, and the mean ± SEM are shown. Data are pooled from two independent experiments with a total of nine mice per group. (B) At day 11 after infection, CD4+ T cells were purified and the expression of Il17a, Rorc, and Irf4 were determined by real-time PCR. The means ± SD are shown (n = 5 mice per group from two independent experiments). (C) IL-17A expression by LP CD4+ T cells was determined by intracellular staining 4 h after stimulation with PMA and ionomycin (left). The mean percentage ± SD of IL-17A–producing CD4+ T cells is shown (right, n = 5 mice per group). Data are representative of two independent experiments. (D) Histological evaluation of representative H&E-stained slides of the colon from WT and DKI mice on day 11 of infection (n = 9 mice per group from 2 independent experiments). Accumulations of lymphocytes are indicated with black circles in WT or arrowheads in DKI mice (left, bar: 100 µm). The thickness of the mucosa is indicated with a black line (middle, bar: 200 µm). Black arrows indicate goblet cells in the colon mucosa (right, bar: 200 µm). (E) The histopathological parameters were quantitated using a double-blinded visual scoring system as detailed in Materials and methods. Data are pooled from 2 independent experiments with a total of 9 mice per group. *, P < 0.05 (unpaired two-tailed Student’s t test).
Mentions: To test the importance of p38 alternative activation in a physiological setting, WT and DKI mice were infected with C. rodentium, for which Th17 cells plays a critical protective role (Curtis and Way, 2009). Mice were analyzed at 11–12 d after infection, which is normally at or near the peak of the response (Johnson and Barthold, 1979). WT mice had more infiltrating lymphocytes in the colonic lamina propria (LP) than DKI mice (Fig. 2 A), and freshly isolated LP CD4+ T cells from DKI mice expressed much lower levels of Rorc and Irf4, transcription factors required for Th17 differentiation, than their WT counterparts (Fig. 2 B). Correspondingly, Il17a mRNA and protein expression was highly impaired in lamina propria CD4+ DKI T cells (Fig. 2, B and C). In agreement with the in vitro analyses, histological examination revealed much greater signs inflammation in the colons of WT compared with DKI mice, with greater lymphocyte infiltration in the LP (Fig. 2 D, left), increased mucosal thickness and hyperplastic and elongated crypts, sometimes with a pseudostratified appearance and obvious increased mitotic activity of enterocytes (Fig. 2 D, middle), as well as marked goblet cell depletion (Fig. 2 D, right). A semiquantitative histopathological analysis of multiple mice confirmed the diminished inflammation in the gut of DKI mice (Fig. 2 E).

Bottom Line: Unlike the MAP kinase (MAPK) cascade that phosphorylates p38 on the activation loop, T cell receptor (TCR) signaling results in phosphorylation on Tyr-323 (pY323, alternative pathway).Notably, UVB treatment of human psoriatic lesions reduced skin-infiltrating p38 pY323(+) T cell IRF4 and IL-17 production.Thus, distinct mechanisms of p38 activation converge on NFATc1 with opposing effects on T cell immunity, which may underlie the beneficial effect of phototherapy on psoriasis.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratory of Immune Cell Biology, Center for Cancer Research; Dermatology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.

ABSTRACT
Unlike the MAP kinase (MAPK) cascade that phosphorylates p38 on the activation loop, T cell receptor (TCR) signaling results in phosphorylation on Tyr-323 (pY323, alternative pathway). Using mice expressing p38α and p38β with Y323F substitutions, we show that alternatively but not MAPK cascade-activated p38 up-regulates the transcription factors NFATc1 and IRF4, which are required for proliferation and cytokine production. Conversely, activation of p38 with UV or osmotic shock mitigated TCR-mediated activation by phosphorylation and cytoplasmic retention of NFATc1. Notably, UVB treatment of human psoriatic lesions reduced skin-infiltrating p38 pY323(+) T cell IRF4 and IL-17 production. Thus, distinct mechanisms of p38 activation converge on NFATc1 with opposing effects on T cell immunity, which may underlie the beneficial effect of phototherapy on psoriasis.

Show MeSH
Related in: MedlinePlus