Autophagy-dependent regulatory T cells are critical for the control of graft-versus-host disease
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
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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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 4

Characterization of BM and splenic TIGIT+ Tregs.

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Characterization of BM and splenic TIGIT+ Tregs. (A and B) Flow cytometr...
(A and B) Flow cytometry analysis of splenic and BM TIGIT+ and TIGITneg CD4+FoxP3-GFP+ or FoxP3-RFP+ Tregs from FoxP3-GFP or IL-10-GFP-FoxP3-RFP naive mice. Expression of KLRG1, CD62L, CD44, CD69, CD25, PD-1, CD73, GITR, ICOS, CTLA4, ICAM-1, and IL-10. The isotype control represents staining of pooled BM and spleen cells. Representative histograms of phenotype analysis (n = 3 from 3 independent experiments). (C) Representative histograms of BCL-2 expression in splenic and BM TIGIT+ and TIGITneg CD4+FoxP3+ cells from C57BL/6 naive mice (n = 3 from 1 experiment). (D) Frequency (%) and intensity (geometric mean) of LC3 expression in splenic and BM TIGIT+ and TIGITneg CD4+CD25+ Tregs from LC3-GFP mice (n = 9 from 3 independent experiments). (E) ATG7 transcripts quantification by RT-qPCR in sorted TIGIT+ and TIGITneg CD4+FoxP3-GFP+ splenic Tregs from FoxP3-GFP naive mice (n = 6 from 3 independent experiments). Data are shown as mean ± SEM. Statistical significance was determined using a Wilcoxon matched-paired test (*P < 0.05; **P < 0.01). Statistical analyses were performed using GraphPad Prism version 6.01 software. TIGIT, T cell immunoreceptor with Ig and ITIM domains; RFP, red fluorescent protein; KLRG1, coinhibitory receptor killer cell lectin-like receptor G1; PD-1, programmed cell death protein 1; GITR, glucocorticoid-induced TNFR-related protein; ICOS, inducible T cell costimulator; CTLA4, cytotoxic T lymphocyte–associated protein 4; ICAM-1, intercellular adhesion molecule 1; BCL-2, B cell lymphoma 2; LC3, microtubule-associated protein light chain 3; Atg, autophagy-related gene.