Essential role for autophagy during invariant NKT cell development.

Area of Science:

• Immunology
• Cell Biology
• Metabolism

Background:

• Autophagy is a vital cellular process for homeostasis, development, and immunity.
• Its role in invariant natural killer T (iNKT) cell development and function is not fully understood.
• The impact of autophagy defects on T cell differentiation and survival requires further investigation.

Purpose of the Study:

• To investigate the role of autophagy in thymic development and peripheral survival of iNKT cells.
• To determine if iNKT cells and conventional T cells share similar autophagy requirements.
• To elucidate the mechanisms by which autophagy impacts iNKT cell differentiation and survival.

Main Methods:

• Conditional deletion of the autophagy gene Atg7 in mouse T cells (CD4 Cre-Atg7(-/-)).
• Analysis of thymic and peripheral iNKT cell development and survival.
• Assessment of mitochondrial content, mitophagy, and reactive oxygen species.
• Comparison of autophagy-deficient iNKT cells and conventional T cells.

Main Results:

• Autophagy deficiency blocks iNKT cell development in the thymus and leads to their absence in peripheral organs.
• This defect is T-cell-intrinsic and results from increased apoptosis, not altered antigen loading.
• Autophagy, particularly mitophagy, is essential for regulating mitochondrial content and preventing oxidative stress during iNKT cell differentiation.
• Autophagy-deficient conventional T cells exhibit impaired peripheral survival, especially memory CD8(+) T cells.

Conclusions:

• Autophagy is indispensable for iNKT cell development and survival through metabolic regulation.
• Autophagy's role in iNKT cell differentiation is unique compared to conventional T cells, impacting their transition to a quiescent state.
• These findings reveal a critical, autophagy-dependent metabolic pathway essential for both innate (iNKT) and adaptive T cells.