Limits...
Conditional Deletion of TAK1 in T Cells Reveals a Pivotal Role of TCRαβ+ Intraepithelial Lymphocytes in Preventing Lymphopenia-Associated Colitis.

Sanjo H, Tokumaru S, Akira S, Taki S - PLoS ONE (2015)

Bottom Line: The kinase TAK is required for the development of conventional and regulatory T cells.Furthermore, the gut microbiota-triggered signaling was also a key event leading to the pathogenesis.Taken together, our current study highlighted the emerging role of TAK1 in configuring the gut-specialized T cell subset, which regulates mucosal homeostasis under lymphopenic conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Immunology, Shinshu University School of Medicine, Nagano, Japan.

ABSTRACT
The kinase TAK is required for the development of conventional and regulatory T cells. We previously reported that mice with conditional deletion of TAK1 in T cells (Lck-cre:TAK1fl/fl mice) exhibited severe T lymphopenia, and were nevertheless predisposed to spontaneous colitis with unknown etiology. Here we focused on the immunopathological mechanism in colitic Lck-cre:TAK1fl/fl mice. We found that 'leaky' CD4+ T cells retaining TAK1 acquired inflammatory phenotypes that contribute to disease onset in Lck-cre:TAK1fl/fl mice. Furthermore, the gut microbiota-triggered signaling was also a key event leading to the pathogenesis. We discovered that Lck-cre:TAK1fl/fl mice were almost completely devoid of TCRαβ+CD8α+ intestinal intraepithelial lymphocytes (IELs) and this was largely due to the developmental defect of the thymic precursors by TAK1 deficiency. Remarkably, transfer of TCRαβ+CD8α+ IELs from wild-type mice ameliorated colitis in Lck-cre:TAK1fl/fl mice. Taken together, our current study highlighted the emerging role of TAK1 in configuring the gut-specialized T cell subset, which regulates mucosal homeostasis under lymphopenic conditions.

No MeSH data available.


Related in: MedlinePlus

Regulatory T cell population in LTAC mice.(A) Flow cytometry analysis with thymocytes from 6-week-old (w.o.) or 11 w.o. WT and LTAC mice. Staining for CD25 and Foxp3 determined Treg in CD4 single positive cells. The plots are representative of three independent experiments. (B) Foxp3 expression in TCRβ+CD4+ cells in tissues indicated. The histograms are representative of at least five independent experiments. (C and D) Frequencies (left) and absolute numbers (right) of Foxp3+ cells of TCRβ+CD4+ cells from the mLNs (C) and cLP (D) of WT (n = 5–8, filled circle) and LTAC mice (n = 5–8, open circle), determined by flow cytometry analysis from (B). Horizontal bars represent mean. (E) Genomic DNAs from the sorted cells indicated, followed by PCR amplification to detect flox or Δ allele in TAK1 genomic locus like Fig 2C. (F) CFSE-labeled CD45.1+CD4+CD25– T cells (Tresp) were cultured with soluble anti-CD3 antibody and T cell-depleted splenocytes in the absence (Tresp alone) or presence of CD4+CD25+ regulatory T cells (Treg) purified from wild-type or LTAC mice for 3 days (The ratio of Tresp to Treg is 2:1.). The histograms are representative of three independent experiments. In (C) and (D), unpaired t tests were performed. Statistical significance was indicated by **P < 0.01, ***P < 0.001; ns, not significant.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4489433&req=5

pone.0128761.g003: Regulatory T cell population in LTAC mice.(A) Flow cytometry analysis with thymocytes from 6-week-old (w.o.) or 11 w.o. WT and LTAC mice. Staining for CD25 and Foxp3 determined Treg in CD4 single positive cells. The plots are representative of three independent experiments. (B) Foxp3 expression in TCRβ+CD4+ cells in tissues indicated. The histograms are representative of at least five independent experiments. (C and D) Frequencies (left) and absolute numbers (right) of Foxp3+ cells of TCRβ+CD4+ cells from the mLNs (C) and cLP (D) of WT (n = 5–8, filled circle) and LTAC mice (n = 5–8, open circle), determined by flow cytometry analysis from (B). Horizontal bars represent mean. (E) Genomic DNAs from the sorted cells indicated, followed by PCR amplification to detect flox or Δ allele in TAK1 genomic locus like Fig 2C. (F) CFSE-labeled CD45.1+CD4+CD25– T cells (Tresp) were cultured with soluble anti-CD3 antibody and T cell-depleted splenocytes in the absence (Tresp alone) or presence of CD4+CD25+ regulatory T cells (Treg) purified from wild-type or LTAC mice for 3 days (The ratio of Tresp to Treg is 2:1.). The histograms are representative of three independent experiments. In (C) and (D), unpaired t tests were performed. Statistical significance was indicated by **P < 0.01, ***P < 0.001; ns, not significant.

Mentions: We previously reported that TAK1 deficiency in T cells resulted in an impaired generation of regulatory T cells [25] and in fact we confirmed a dramatic reduction in the frequency of CD25+Foxp3+ cells in CD4 single positive thymocytes of 6-week-old LTAC mice in which colitis does not appear (Fig 3A). Unexpectedly, however, we recognized regulatory T cells in peripheral tissues such as mLNs and cLP of more than 10-week-old LTAC mice as well as wild-type mice and its frequency was significantly higher and lower in the mLNs and cLP, respectively, of LTAC mice than those of wild-type mice (Fig 3B–3D), whilst absolute numbers of regulatory T cells were virtually unchanged in the mLNs and cLP of both types of mice (Fig 3C and 3D). When we checked regulatory T cells in the thymus of more than 10-week-old LTAC mice, we noticed that CD4+CD25+Foxp3+ regulatory T cells were as frequent as those in wild-type mice (Fig 3A). Having observed the failure of TAK1 deletion in the remaining CD4+ T cells in peripheral tissues of LTAC mice, it would be plausible that the regulatory T cells in LTAC mice still possess intact TAK1. Indeed, the cells sorted from mLNs of LTAC mice showed virtually no sign for deletion of the TAK1 genomic locus (Fig 3E), indicating that regulatory T cells we observed in LTAC mice have intact TAK1. When we performed in vitro suppression assay to investigate regulatory T cell function, intriguingly, regulatory T cells in LTAC mice showed less suppressive activity than that of wild-type regulatory T cells (Fig 3F). Taken together, these data suggested that failure of suppressive function of the leaky regulatory T cells facilitated the pathogenesis of colitis in LTAC mice.


Conditional Deletion of TAK1 in T Cells Reveals a Pivotal Role of TCRαβ+ Intraepithelial Lymphocytes in Preventing Lymphopenia-Associated Colitis.

Sanjo H, Tokumaru S, Akira S, Taki S - PLoS ONE (2015)

Regulatory T cell population in LTAC mice.(A) Flow cytometry analysis with thymocytes from 6-week-old (w.o.) or 11 w.o. WT and LTAC mice. Staining for CD25 and Foxp3 determined Treg in CD4 single positive cells. The plots are representative of three independent experiments. (B) Foxp3 expression in TCRβ+CD4+ cells in tissues indicated. The histograms are representative of at least five independent experiments. (C and D) Frequencies (left) and absolute numbers (right) of Foxp3+ cells of TCRβ+CD4+ cells from the mLNs (C) and cLP (D) of WT (n = 5–8, filled circle) and LTAC mice (n = 5–8, open circle), determined by flow cytometry analysis from (B). Horizontal bars represent mean. (E) Genomic DNAs from the sorted cells indicated, followed by PCR amplification to detect flox or Δ allele in TAK1 genomic locus like Fig 2C. (F) CFSE-labeled CD45.1+CD4+CD25– T cells (Tresp) were cultured with soluble anti-CD3 antibody and T cell-depleted splenocytes in the absence (Tresp alone) or presence of CD4+CD25+ regulatory T cells (Treg) purified from wild-type or LTAC mice for 3 days (The ratio of Tresp to Treg is 2:1.). The histograms are representative of three independent experiments. In (C) and (D), unpaired t tests were performed. Statistical significance was indicated by **P < 0.01, ***P < 0.001; ns, not significant.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4489433&req=5

pone.0128761.g003: Regulatory T cell population in LTAC mice.(A) Flow cytometry analysis with thymocytes from 6-week-old (w.o.) or 11 w.o. WT and LTAC mice. Staining for CD25 and Foxp3 determined Treg in CD4 single positive cells. The plots are representative of three independent experiments. (B) Foxp3 expression in TCRβ+CD4+ cells in tissues indicated. The histograms are representative of at least five independent experiments. (C and D) Frequencies (left) and absolute numbers (right) of Foxp3+ cells of TCRβ+CD4+ cells from the mLNs (C) and cLP (D) of WT (n = 5–8, filled circle) and LTAC mice (n = 5–8, open circle), determined by flow cytometry analysis from (B). Horizontal bars represent mean. (E) Genomic DNAs from the sorted cells indicated, followed by PCR amplification to detect flox or Δ allele in TAK1 genomic locus like Fig 2C. (F) CFSE-labeled CD45.1+CD4+CD25– T cells (Tresp) were cultured with soluble anti-CD3 antibody and T cell-depleted splenocytes in the absence (Tresp alone) or presence of CD4+CD25+ regulatory T cells (Treg) purified from wild-type or LTAC mice for 3 days (The ratio of Tresp to Treg is 2:1.). The histograms are representative of three independent experiments. In (C) and (D), unpaired t tests were performed. Statistical significance was indicated by **P < 0.01, ***P < 0.001; ns, not significant.
Mentions: We previously reported that TAK1 deficiency in T cells resulted in an impaired generation of regulatory T cells [25] and in fact we confirmed a dramatic reduction in the frequency of CD25+Foxp3+ cells in CD4 single positive thymocytes of 6-week-old LTAC mice in which colitis does not appear (Fig 3A). Unexpectedly, however, we recognized regulatory T cells in peripheral tissues such as mLNs and cLP of more than 10-week-old LTAC mice as well as wild-type mice and its frequency was significantly higher and lower in the mLNs and cLP, respectively, of LTAC mice than those of wild-type mice (Fig 3B–3D), whilst absolute numbers of regulatory T cells were virtually unchanged in the mLNs and cLP of both types of mice (Fig 3C and 3D). When we checked regulatory T cells in the thymus of more than 10-week-old LTAC mice, we noticed that CD4+CD25+Foxp3+ regulatory T cells were as frequent as those in wild-type mice (Fig 3A). Having observed the failure of TAK1 deletion in the remaining CD4+ T cells in peripheral tissues of LTAC mice, it would be plausible that the regulatory T cells in LTAC mice still possess intact TAK1. Indeed, the cells sorted from mLNs of LTAC mice showed virtually no sign for deletion of the TAK1 genomic locus (Fig 3E), indicating that regulatory T cells we observed in LTAC mice have intact TAK1. When we performed in vitro suppression assay to investigate regulatory T cell function, intriguingly, regulatory T cells in LTAC mice showed less suppressive activity than that of wild-type regulatory T cells (Fig 3F). Taken together, these data suggested that failure of suppressive function of the leaky regulatory T cells facilitated the pathogenesis of colitis in LTAC mice.

Bottom Line: The kinase TAK is required for the development of conventional and regulatory T cells.Furthermore, the gut microbiota-triggered signaling was also a key event leading to the pathogenesis.Taken together, our current study highlighted the emerging role of TAK1 in configuring the gut-specialized T cell subset, which regulates mucosal homeostasis under lymphopenic conditions.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cellular Immunology, Shinshu University School of Medicine, Nagano, Japan.

ABSTRACT
The kinase TAK is required for the development of conventional and regulatory T cells. We previously reported that mice with conditional deletion of TAK1 in T cells (Lck-cre:TAK1fl/fl mice) exhibited severe T lymphopenia, and were nevertheless predisposed to spontaneous colitis with unknown etiology. Here we focused on the immunopathological mechanism in colitic Lck-cre:TAK1fl/fl mice. We found that 'leaky' CD4+ T cells retaining TAK1 acquired inflammatory phenotypes that contribute to disease onset in Lck-cre:TAK1fl/fl mice. Furthermore, the gut microbiota-triggered signaling was also a key event leading to the pathogenesis. We discovered that Lck-cre:TAK1fl/fl mice were almost completely devoid of TCRαβ+CD8α+ intestinal intraepithelial lymphocytes (IELs) and this was largely due to the developmental defect of the thymic precursors by TAK1 deficiency. Remarkably, transfer of TCRαβ+CD8α+ IELs from wild-type mice ameliorated colitis in Lck-cre:TAK1fl/fl mice. Taken together, our current study highlighted the emerging role of TAK1 in configuring the gut-specialized T cell subset, which regulates mucosal homeostasis under lymphopenic conditions.

No MeSH data available.


Related in: MedlinePlus