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 6

Deletion of Tet2 and expression of RhoAG17V synergistically regulate FoxO1 activity.

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Deletion of Tet2 and expression of RhoAG17V synergistically regulate Fox...
(A) Real-time reverse transcription PCR (RT-PCR) analysis of FoxO1 gene expression (normalized to Gapdh) in Thy1.2+GFP+CD4+ T cells isolated from peripheral lymphoid tissues of recipient mice. The mice were adoptively transferred with WT, RhoAG17V, Tet2–/–, or Tet2–/– RhoAG17V T cells. Results are presented as the fold change relative to WT (arbitrarily set to 1). Data from 5 independent experiments are shown. ***P < 0.001, by 2-tailed Student’s t test. (B) Immunoblot analysis showing the expression of total and phosphorylated FoxO1 in GFP+CD4+ T cells (WT, RhoAG17V, Tet2–/–, or Tet2–/– RhoAG17V) that were in vitro–activated for 4 days. GAPDH served as a loading control. (C) Representative confocal images showing immunostaining of p-FoxO1 in WT, RhoAG17V, Tet2–/–, and Tet2–/– RhoAG17V in vitro–activated GFP+CD4+ T cells. (D) PCA and cluster analysis (inset) of the DNA methylation status of the CpG island (CGI) at the FoxO1 promoter in GFP+CD4+ T cells from mice of the indicated groups. The Tet2–/– and Tet2–/– RhoAG17V groups were most closely related. (E) Immunoblot analysis showing the expression of total and phosphorylated Akt and MST1 in GFP+CD4+ T cells (in vitro–activated for 4 days) from mice of the indicated groups. GAPDH served as a loading control. (F) Immunohistochemical analysis of FoxO1 distribution in normal human lymph nodes (top left) and lymphoma biopsies isolated from patients with AITL bearing both TET2 and RhoA mutations (top) or TET2 mutations alone (bottom). Scale bar: 50 μm. Original magnification: ×40.