Essential role for autophagy during invariant NKT cell development

Item Type:	Article
Title:	Essential role for autophagy during invariant NKT cell development
Creators Name:	Salio, M. and Puleston, D.J. and Mathan, T.S.M. and Shepherd, D. and Stranks, A.J. and Adamopoulou, E. and Veerapen, N. and Besra, G.S. and Hollander, G.A. and Simon, A.K. and Cerundolo, V.
Abstract:	Autophagy is an evolutionarily conserved cellular homeostatic pathway essential for development, immunity, and cell death. Although autophagy modulates MHC antigen presentation, it remains unclear whether autophagy defects impact on CD1d lipid loading and presentation to invariant natural killer T (iNKT) cells and on iNKT cell differentiation in the thymus. Furthermore, it remains unclear whether iNKT and conventional T cells have similar autophagy requirements for differentiation, survival, and/or activation. We report that, in mice with a conditional deletion of the essential autophagy gene Atg7 in the T-cell compartment (CD4 Cre-Atg7(−/−)), thymic iNKT cell development—unlike conventional T-cell development—is blocked at an early stage and mature iNKT cells are absent in peripheral lymphoid organs. The defect is not due to altered loading of intracellular iNKT cell agonists; rather, it is T-cell–intrinsic, resulting in enhanced susceptibility of iNKT cells to apoptosis. We show that autophagy increases during iNKT cell thymic differentiation and that it developmentally regulates mitochondrial content through mitophagy in the thymus of mice and humans. Autophagy defects result in the intracellular accumulation of mitochondrial superoxide species and subsequent apoptotic cell death. Although autophagy-deficient conventional T cells develop normally, they show impaired peripheral survival, particularly memory CD8(+) T cells. Because iNKT cells, unlike conventional T cells, differentiate into memory cells while in the thymus, our results highlight a unique autophagy-dependent metabolic regulation of adaptive and innate T cells, which is required for transition to a quiescent state after population expansion.
Keywords:	Apoptosis, Autophagy, Autophagy-Related Protein 7, CD8-Positive T-Lymphocytes, Cell Differentiation, Cell Survival, Immunologic Memory, Knockout Mice, Microtubule-Associated Proteins, Natural Killer T-Cells, Superoxides, Thymus Gland, Animals, Mice
Source:	Proceedings of the National Academy of Sciences of the United States of America
ISSN:	0027-8424
Publisher:	National Academy of Sciences
Volume:	111
Number:	52
Page Range:	E5678-E5687
Date:	30 December 2014
Additional Information:	Freely available online through the PNAS open access option.
Official Publication:	https://doi.org/10.1073/pnas.1413935112
External Fulltext:	View full text on PubMed Central
PubMed:	View item in PubMed

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