Iron deficiency causes aspartate-sensitive dysfunction in CD8⁺ T cells.

Area of Science:

• Immunology
• Cellular Metabolism
• Nutritional Biochemistry

Background:

• Iron is essential for cellular metabolism and immune function.
• Iron deficiency affects over a billion people globally, impairing immunity.
• The precise impact of iron deprivation on CD8+ T cell function is not well understood.

Purpose of the Study:

• To investigate how low iron availability affects CD8+ T cell metabolism and function.
• To elucidate the molecular mechanisms underlying immune impairment in iron deficiency.

Main Methods:

• Multi-omic analysis (genomics, transcriptomics, proteomics).
• Metabolic labeling techniques.
• Assessment of mitochondrial function and cellular proliferation.

Main Results:

• Iron limitation significantly impairs CD8+ T cell proliferation and mitochondrial membrane potential.
• TCA cycle metabolism is altered, with a shift towards a reductive trajectory.
• Aspartate accumulates but is not utilized for nucleotide synthesis due to mitochondrial dysfunction.
• Exogenous aspartate partially rescues CD8+ T cell expansion and function.

Conclusions:

• Iron scarcity creates a metabolic bottleneck in mitochondria, hindering CD8+ T cell function.
• Aspartate supplementation can bypass this bottleneck, restoring some immune cell capabilities.
• These findings provide mechanistic insights into immune dysfunction caused by iron deficiency.