Mutations in 5-methylcytosine oxidase TET2 and RhoA cooperatively disrupt T cell homeostasis
Shengbing Zang, … , Deqiang Sun, Yun Huang
Shengbing Zang, … , Deqiang Sun, Yun Huang
Published July 10, 2017
Citation Information: J Clin Invest. 2017;127(8):2998-3012. https://doi.org/10.1172/JCI92026.
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Research Article Hematology Immunology

Mutations in 5-methylcytosine oxidase TET2 and RhoA cooperatively disrupt T cell homeostasis

Abstract

Angioimmunoblastic T cell lymphoma (AITL) represents a distinct, aggressive form of peripheral T cell lymphoma with a dismal prognosis. Recent exome sequencing in patients with AITL has revealed the frequent coexistence of somatic mutations in the Rho GTPase RhoA (RhoAG17V) and loss-of-function mutations in the 5-methylcytosine oxidase TET2. Here, we have demonstrated that TET2 loss and RhoAG17V expression in mature murine T cells cooperatively cause abnormal CD4+ T cell proliferation and differentiation by perturbing FoxO1 gene expression, phosphorylation, and subcellular localization, an abnormality that is also detected in human primary AITL tumor samples. Reexpression of FoxO1 attenuated aberrant immune responses induced in mouse models adoptively transferred with T cells and bearing genetic lesions in both TET2 and RhoA. Our findings suggest a mutational cooperativity between epigenetic factors and GTPases in adult CD4+ T cells that may account for immunoinflammatory responses associated with AITL patients.

Authors

Shengbing Zang, Jia Li, Haiyan Yang, Hongxiang Zeng, Wei Han, Jixiang Zhang, Minjung Lee, Margie Moczygemba, Sevinj Isgandarova, Yaling Yang, Yubin Zhou, Anjana Rao, M. James You, Deqiang Sun, Yun Huang

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Figure 3

TET2 depletion and RhoAG17V expression suppress cell death and disrupt peripheral T cell homeostasis.

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TET2 depletion and RhoAG17V expression suppress cell death and disrupt p...
(A) Flow cytometric analysis of NucRed live), annexin V, and Fas staining in in vitro–activated GFP+CD4+ T cells (day 4). Representative flow cytometric plots for each indicated group. Bar graphs show quantification of the percentages of cells with positive staining (n = 3 independent experiments). (B) Immunoblots showing the detection of cleaved caspase-3, p21, and cyclin D1 on day 4 following in vitro activation of CD4+ T cells (WT, RhoAG17V, Tet2–/–, or Tet2–/– RhoAG17V). GAPDH served as a loading control. MW, molecular weight. (C) Representative flow cytometric plots of Thy1.2+GFP+CD4+ T cells isolated from spleens and lymph nodes from recipient mice adoptively transferred with WT, RhoAG17V, Tet2–/–, or Tet2–/– RhoAG17V T cells (20 weeks after transfer). Bar graphs show quantification of the percentages of CD4+ T cells (n = 3 mice, 1 experiment) with positive staining for CD44, IL-17α (Th17 marker), or Foxp3 (Treg marker). (D) Representative flow cytometric plots of Thy1.2+, GFP+, and CD4+ gated Tfh cells isolated from spleens and lymph nodes from recipient mice adoptively transferred with WT, RhoAG17V, Tet2–/–, or Tet2–/– RhoAG17V T cells (20 weeks after transfer). Bar graph shows quantification of the percentages of CXCR5+BCL-6+ Tfh cells (n = 3 mice; 1 experiment). Data represent the mean ± SD. *P < 0.05 and ***P < 0.001, by ANOVA with Dunnett’s method for multiple comparisons.