Autophagy-dependent regulatory T cells are critical for the control of graft-versus-host disease
Laëtitia Le Texier, … , Geoffrey R. Hill, Kelli P.A. MacDonald
Laëtitia Le Texier, … , Geoffrey R. Hill, Kelli P.A. MacDonald
Published September 22, 2016
Citation Information: JCI Insight. 2016;1(15):e86850. https://doi.org/10.1172/jci.insight.86850.
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Research Article Immunology Transplantation

Autophagy-dependent regulatory T cells are critical for the control of graft-versus-host disease

Abstract

Regulatory T cells (Tregs) play a crucial role in the maintenance of peripheral tolerance. Quantitative and/or qualitative defects in Tregs result in diseases such as autoimmunity, allergy, malignancy, and graft-versus-host disease (GVHD), a serious complication of allogeneic stem cell transplantation (SCT). We recently reported increased expression of autophagy-related genes (Atg) in association with enhanced survival of Tregs after SCT. Autophagy is a self-degradative process for cytosolic components that promotes cell homeostasis and survival. Here, we demonstrate that the disruption of autophagy within FoxP3+ Tregs (B6.Atg7fl/fl-FoxP3cre+) resulted in a profound loss of Tregs, particularly within the bone marrow (BM). This resulted in dysregulated effector T cell activation and expansion, and the development of enterocolitis and scleroderma in aged mice. We show that the BM compartment is highly enriched in TIGIT+ Tregs and that this subset is differentially depleted in the absence of autophagy. Moreover, following allogeneic SCT, recipients of grafts from B6.Atg7fl/fl-FoxP3cre+ donors exhibited reduced Treg reconstitution, exacerbated GVHD, and reduced survival compared with recipients of B6.WT-FoxP3cre+ grafts. Collectively, these data indicate that autophagy-dependent Tregs are critical for the maintenance of tolerance after SCT and that the promotion of autophagy represents an attractive immune-restorative therapeutic strategy after allogeneic SCT.

Authors

Laëtitia Le Texier, Katie E. Lineburg, Benjamin Cao, Cameron McDonald-Hyman, Lucie Leveque-El Mouttie, Jemma Nicholls, Michelle Melino, Blessy C. Nalkurthi, Kylie A. Alexander, Bianca Teal, Stephen J. Blake, Fernando Souza-Fonseca-Guimaraes, Christian R. Engwerda, Rachel D. Kuns, Steven W. Lane, Michele Teng, Charis Teh, Daniel Gray, Andrew D. Clouston, Susan K. Nilsson, Bruce R. Blazar, Geoffrey R. Hill, Kelli P.A. MacDonald

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Figure 1

Autophagy is an active process in Tregs and required for their maintenance in the periphery.

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Autophagy is an active process in Tregs and required for their maintenan...
(A and B) Analysis of freshly isolated splenic CD4+CD25– Tcon and CD4+CD25+ Tregs from LC3-GFP mice. (A) Representative histograms of flow cytometry analysis for LC3 expression. Frequency of LC3+ cells in CD4+CD25– Tcon cells and CD4+CD25+ Tregs (5 independent experiments; n = 6). (B) Representative pictures of imaging flow cytometry (AMNIS) analysis of LC3 puncta formation in CD4+FoxP3neg Tcon and CD4+FoxP3+ Treg populations isolated from FoxP3-GFP mice incubated with or without CQ. Mean of LC3 puncta/cell (n = 6 from 3 independent experiments). (C) Total thymus, spleen, and BM cell counts in WT (n = 5) and Atg5–/– FLC mice (n = 5 from 2 independent experiments). (D) Representative dot plot of flow cytometry analysis of FoxP3+ cells in CD4+CD8–CD3+CD45.2+CD45.1– T cells. Frequency (%) and absolute number (#) of total CD4+ T cells and CD4+FoxP3+ Tregs in thymus, spleen, and BM of WT and Atg5–/– FLC mice (n = 5 from 2 independent experiments). (E) Representative dot plot of flow cytometry analysis of Atg7–/– (YFP+) and WT (YFP–) CD4+FoxP3+ Tregs in CD4+CD8–CD3+CD45.2+CD45.1– T cells in the spleen of tamoxifen-treated Ptprca recipient of BM from Atg7fl/fl-SCLcre ERT-Rosa26 eYFP mice. Frequency (%) of FoxP3+ cells in CD4+ cells (n = 10 from 2 independent experiments). (F) Frequency (%) and absolute number (#) of FoxP3+ T cells in CD4+CD8–CD3+ cells of thymus, spleen, and BM from Atg7fl/fl-FoxP3creneg (WT) and Atg7fl/fl-FoxP3cre+ (Atg7–/–) mice (n = 7–8 from 2 independent experiments). Data are shown as mean ± SEM. Statistical significance was determined using an unpaired 2-tailed Mann-Whitney U test (*P < 0.05; **P < 0.01; ***P < 0.001). Statistical analyses were performed using GraphPad Prism version 6.01 software. LC3, microtubule-associated protein light chain 3; Tcon, conventional T cells; CQ, chloroquine; Atg, autophagy-related gene; FLC, fetal liver chimeras; YFP, yellow fluorescent protein.