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DNA Repair Cofactors ATMIN and NBS1 Are Required to Suppress T Cell Activation.

Prochazkova J, Sakaguchi S, Owusu M, Mazouzi A, Wiedner M, Velimezi G, Moder M, Turchinovich G, Hladik A, Gurnhofer E, Hayday A, Behrens A, Knapp S, Kenner L, Ellmeier W, Loizou JI - PLoS Genet. (2015)

Bottom Line: We show loss of NBS1 led to a developmental block at the double-positive stage of T cell development, as well as reduced TCRα recombination, that was unexpectedly neither exacerbated nor alleviated by concomitant loss of ATMIN.In vivo this resulted in severe intestinal inflammation, colitis and premature death.Our findings reveal a novel model for an intestinal bowel disease phenotype that occurs upon combined loss of the DNA repair cofactors ATMIN and NBS1.

View Article: PubMed Central - PubMed

Affiliation: CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.

ABSTRACT
Proper development of the immune system is an intricate process dependent on many factors, including an intact DNA damage response. The DNA double-strand break signaling kinase ATM and its cofactor NBS1 are required during T cell development and for the maintenance of genomic stability. The role of a second ATM cofactor, ATMIN (also known as ASCIZ) in T cells is much less clear, and whether ATMIN and NBS1 function in synergy in T cells is unknown. Here, we investigate the roles of ATMIN and NBS1, either alone or in combination, using murine models. We show loss of NBS1 led to a developmental block at the double-positive stage of T cell development, as well as reduced TCRα recombination, that was unexpectedly neither exacerbated nor alleviated by concomitant loss of ATMIN. In contrast, loss of both ATMIN and NBS1 enhanced DNA damage that drove spontaneous peripheral T cell hyperactivation, proliferation as well as excessive production of proinflammatory cytokines and chemokines, leading to a highly inflammatory environment. Intriguingly, the disease causing T cells were largely proficient for both ATMIN and NBS1. In vivo this resulted in severe intestinal inflammation, colitis and premature death. Our findings reveal a novel model for an intestinal bowel disease phenotype that occurs upon combined loss of the DNA repair cofactors ATMIN and NBS1.

No MeSH data available.


Related in: MedlinePlus

Loss of ATMIN and NBS1 leads to intestinal inflammation due to infiltration of cytokine-producing T cells.(A) Histological analysis by H&E staining of large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL mice at 12 weeks of age. (B) Histological scores of the large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL and 3 individual moribund ATMINΔLNBS1ΔL mice. (C) Histological analysis by anti-CD3 staining of the large intestine of control and a moribund ATMINΔLNBS1ΔL mouse. (D) Representative flow cytometry data of CD4 and CD8 expression, as well as (E) TCRβ and TCRγδ expression on isolated IELs from the small intestine of control, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice, along with the quantification of D-E. N = 5–8 mice per genotype. (F) Representative flow cytometry data of IL17A and IFNγ production by YFP- and YFP+ IELs (gated on the CD4+ population) isolated from the small intestine of control and ATMINΔLNBS1ΔL mice after PMA and ionomycin stimulation. (G) Large intestinal sections from control, ATM-/-, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice were stained for γH2AX and DAPI. Error bars represent SEM (**P<0.01, ***P<0.001).
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pgen.1005645.g005: Loss of ATMIN and NBS1 leads to intestinal inflammation due to infiltration of cytokine-producing T cells.(A) Histological analysis by H&E staining of large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL mice at 12 weeks of age. (B) Histological scores of the large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL and 3 individual moribund ATMINΔLNBS1ΔL mice. (C) Histological analysis by anti-CD3 staining of the large intestine of control and a moribund ATMINΔLNBS1ΔL mouse. (D) Representative flow cytometry data of CD4 and CD8 expression, as well as (E) TCRβ and TCRγδ expression on isolated IELs from the small intestine of control, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice, along with the quantification of D-E. N = 5–8 mice per genotype. (F) Representative flow cytometry data of IL17A and IFNγ production by YFP- and YFP+ IELs (gated on the CD4+ population) isolated from the small intestine of control and ATMINΔLNBS1ΔL mice after PMA and ionomycin stimulation. (G) Large intestinal sections from control, ATM-/-, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice were stained for γH2AX and DAPI. Error bars represent SEM (**P<0.01, ***P<0.001).

Mentions: A proportion of ATMINΔLNBS1ΔL mice became moribund and displayed systemic inflammation, which also involved the intestine since we observed the development of spontaneous intestinal prolapses. We histologically investigated the large intestine that was found to be thickened and inflamed (Fig 5A). Moreover, histological scoring of the spontaneously sick ATMINΔLNBS1ΔL mice revealed extensive inflammation of the intestine (Fig 5B).


DNA Repair Cofactors ATMIN and NBS1 Are Required to Suppress T Cell Activation.

Prochazkova J, Sakaguchi S, Owusu M, Mazouzi A, Wiedner M, Velimezi G, Moder M, Turchinovich G, Hladik A, Gurnhofer E, Hayday A, Behrens A, Knapp S, Kenner L, Ellmeier W, Loizou JI - PLoS Genet. (2015)

Loss of ATMIN and NBS1 leads to intestinal inflammation due to infiltration of cytokine-producing T cells.(A) Histological analysis by H&E staining of large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL mice at 12 weeks of age. (B) Histological scores of the large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL and 3 individual moribund ATMINΔLNBS1ΔL mice. (C) Histological analysis by anti-CD3 staining of the large intestine of control and a moribund ATMINΔLNBS1ΔL mouse. (D) Representative flow cytometry data of CD4 and CD8 expression, as well as (E) TCRβ and TCRγδ expression on isolated IELs from the small intestine of control, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice, along with the quantification of D-E. N = 5–8 mice per genotype. (F) Representative flow cytometry data of IL17A and IFNγ production by YFP- and YFP+ IELs (gated on the CD4+ population) isolated from the small intestine of control and ATMINΔLNBS1ΔL mice after PMA and ionomycin stimulation. (G) Large intestinal sections from control, ATM-/-, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice were stained for γH2AX and DAPI. Error bars represent SEM (**P<0.01, ***P<0.001).
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pgen.1005645.g005: Loss of ATMIN and NBS1 leads to intestinal inflammation due to infiltration of cytokine-producing T cells.(A) Histological analysis by H&E staining of large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL mice at 12 weeks of age. (B) Histological scores of the large intestine of control, ATM-/-, ATMINΔL, NBS1ΔL, ATMINΔLNBS1ΔL and 3 individual moribund ATMINΔLNBS1ΔL mice. (C) Histological analysis by anti-CD3 staining of the large intestine of control and a moribund ATMINΔLNBS1ΔL mouse. (D) Representative flow cytometry data of CD4 and CD8 expression, as well as (E) TCRβ and TCRγδ expression on isolated IELs from the small intestine of control, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice, along with the quantification of D-E. N = 5–8 mice per genotype. (F) Representative flow cytometry data of IL17A and IFNγ production by YFP- and YFP+ IELs (gated on the CD4+ population) isolated from the small intestine of control and ATMINΔLNBS1ΔL mice after PMA and ionomycin stimulation. (G) Large intestinal sections from control, ATM-/-, ATMINΔL, NBS1ΔL and ATMINΔLNBS1ΔL mice were stained for γH2AX and DAPI. Error bars represent SEM (**P<0.01, ***P<0.001).
Mentions: A proportion of ATMINΔLNBS1ΔL mice became moribund and displayed systemic inflammation, which also involved the intestine since we observed the development of spontaneous intestinal prolapses. We histologically investigated the large intestine that was found to be thickened and inflamed (Fig 5A). Moreover, histological scoring of the spontaneously sick ATMINΔLNBS1ΔL mice revealed extensive inflammation of the intestine (Fig 5B).

Bottom Line: We show loss of NBS1 led to a developmental block at the double-positive stage of T cell development, as well as reduced TCRα recombination, that was unexpectedly neither exacerbated nor alleviated by concomitant loss of ATMIN.In vivo this resulted in severe intestinal inflammation, colitis and premature death.Our findings reveal a novel model for an intestinal bowel disease phenotype that occurs upon combined loss of the DNA repair cofactors ATMIN and NBS1.

View Article: PubMed Central - PubMed

Affiliation: CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria.

ABSTRACT
Proper development of the immune system is an intricate process dependent on many factors, including an intact DNA damage response. The DNA double-strand break signaling kinase ATM and its cofactor NBS1 are required during T cell development and for the maintenance of genomic stability. The role of a second ATM cofactor, ATMIN (also known as ASCIZ) in T cells is much less clear, and whether ATMIN and NBS1 function in synergy in T cells is unknown. Here, we investigate the roles of ATMIN and NBS1, either alone or in combination, using murine models. We show loss of NBS1 led to a developmental block at the double-positive stage of T cell development, as well as reduced TCRα recombination, that was unexpectedly neither exacerbated nor alleviated by concomitant loss of ATMIN. In contrast, loss of both ATMIN and NBS1 enhanced DNA damage that drove spontaneous peripheral T cell hyperactivation, proliferation as well as excessive production of proinflammatory cytokines and chemokines, leading to a highly inflammatory environment. Intriguingly, the disease causing T cells were largely proficient for both ATMIN and NBS1. In vivo this resulted in severe intestinal inflammation, colitis and premature death. Our findings reveal a novel model for an intestinal bowel disease phenotype that occurs upon combined loss of the DNA repair cofactors ATMIN and NBS1.

No MeSH data available.


Related in: MedlinePlus