Foxp3 drives oxidative phosphorylation and protection from lipotoxicity

Area of Science:

• Immunology
• Cellular Metabolism
• Molecular Biology

Background:

• Regulatory T cells (Tregs) exhibit a catabolic metabolic program, favoring fatty acid oxidation for oxidative phosphorylation (OXPHOS).
• The precise drivers for this metabolic preference in Tregs, whether environmental or intrinsic, remain incompletely understood.
• The role of the transcription factor Foxp3 in dictating this metabolic phenotype is a key question.

Purpose of the Study:

• To elucidate the role of Foxp3 in programming the metabolic capabilities of Tregs.
• To investigate whether Foxp3 is sufficient to induce a fatty acid oxidation-fueled OXPHOS program in Tregs.
• To identify the molecular mechanisms by which Foxp3 influences Treg metabolism and function.

Main Methods:

• Comprehensive metabolic analysis of Tregs.
• Unbiased mass spectrometry-based proteomics to identify protein expression changes.
• Assessment of respiratory capacity and ATP generation.
• Evaluation of fatty acid utilization and cell survival under fatty acid stress.

Main Results:

• Foxp3 was found to be both necessary and sufficient for programming increased respiratory capacity in Tregs.
• Foxp3 upregulates components of the electron transport chain, enhancing OXPHOS and ATP production.
• Tregs exhibit an increased ability to utilize fatty acids to fuel OXPHOS, driven by Foxp3.
• Increased fatty acid beta-oxidation confers selective protection against fatty acid-induced cell death in Foxp3+ Tregs.

Conclusions:

• Foxp3 is a critical determinant of Treg metabolic programming, specifically promoting fatty acid oxidation-fueled OXPHOS.
• This Foxp3-driven metabolic adaptation enhances Treg bioenergetics and confers a survival advantage.
• The findings suggest potential therapeutic targets for modulating Treg function by manipulating their metabolic pathways.