Itch expression by Treg cells controls Th2 inflammatory responses
Hyung-seung Jin, … , Chris Elly, Yun-Cai Liu
Hyung-seung Jin, … , Chris Elly, Yun-Cai Liu
Published October 25, 2013
Citation Information: J Clin Invest. 2013;123(11):4923-4934. https://doi.org/10.1172/JCI69355.
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Research Article

Itch expression by Treg cells controls Th2 inflammatory responses

Abstract

Regulatory T (Treg) cells maintain immune homeostasis by limiting autoimmune and inflammatory responses. Treg differentiation, maintenance, and function are controlled by the transcription factor Foxp3. However, the exact molecular mechanisms underlying Treg cell regulation remain elusive. Here, we show that Treg cell–specific ablation of the E3 ubiquitin ligase Itch in mice caused massive multiorgan lymphocyte infiltration and skin lesions, chronic T cell activation, and the development of severe antigen-induced airway inflammation. Surprisingly, Foxp3 expression, homeostasis, and the in vitro and in vivo suppressive capability of Treg cells were not affected by Itch deficiency. We found that the expression of Th2 cytokines by Treg cells was increased in the absence of Itch. Fate mapping revealed that a fraction of Treg cells lost Foxp3 expression independently of Itch. However, Th2 cytokines were excessively augmented in Itch–/– Foxp3-negative “ex-Treg” cells without altering the percentage of conversion. Targeted knockdown of Th2 transcriptional regulators in Itch–/– Treg cells prevented Th2 cytokine production. The present study unveils a mechanism of Treg cell acquisition of Th2-like properties that is independent of Foxp3 function and Treg cell stability.

Authors

Hyung-seung Jin, Yoon Park, Chris Elly, Yun-Cai Liu

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Figure 5

Loss of Itch in Treg cells resulted in the acquisition of Th2-like properties.

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Loss of Itch in Treg cells resulted in the acquisition of Th2-like prope...
(A and B) FACS-sorted CD4+YFP+RFP+ Treg cells (A) or CD4+YFP–RFP+ ex-Treg cells (B) from the spleens of WTR26R and ItchR26R mice were stimulated with anti-CD3 and anti-CD28 antibodies for 48 hours in vitro. Cytokine production was measured by Bio-Plex multicytokine assay. Data are compiled from three independent experiments. Error bars indicate the mean (± SD). (C) Flow cytometric analysis of CD62L and CD44 expression on YFP+CD4+ Treg cells in 8-week-old Itchfl/flFoxp3Cre mice and Itch+/+Foxp3Cre littermates. (D) Expression of Treg cell–associated molecules (GITR, ICOS, CTLA4, and CD25) on wild-type and Itch-deficient Treg cells. (E) Flow cytometric analysis of FACS-sorted CD4+YFP+ Treg cells stimulated with anti-CD3 and anti-CD28 antibodies for 2 days in the absence of IL-2 (upper panel). Anti–IL-4 antibody was added as indicated at 10 μg/ml. Percentages of events in the live gates (7-AADlo and FSChi) by flow cytometric analyses are shown in the bar graph (lower panel). (F) Violet dye–labeled FACS-sorted YFP+ Treg cells were stimulated with anti-CD3/CD28 antibodies for 4 days in the presence of IL-2. Cell division was analyzed by flow cytometry. All results are representative of at least three experiments. *P < 0.05 (unpaired 2-tailed Student’s t test).