Divergent Cellular Energetics, Glutamate Metabolism, and Mitochondrial Function Between Human and Mouse Cerebral...

Area of Science:

• Neuroscience
• Metabolic research
• Comparative biology

Background:

• Brain energy and neurotransmitter metabolism disruptions are linked to neurodegenerative diseases like Alzheimer's.
• Rodent models are common for studying brain metabolism, but human-specific differences exist.

Purpose of the Study:

• To compare metabolic functions between human and mouse brain tissue.
• To identify key differences in cellular metabolism relevant for disease modeling.

Main Methods:

• Acutely isolated brain slices and non-synaptic mitochondria from human and mouse cerebral cortex were analyzed.
• Dynamic isotope labeling with 13C-enriched substrates was used to trace metabolic pathways.
• Oxygen consumption rates and mitochondrial coupling were measured.

Main Results:

• Human brain slices exhibited lower metabolic rates for glucose, acetate, β-hydroxybutyrate, and glutamine compared to mouse slices.
• Human slices showed higher glutamate-to-glutamine conversion supporting GABA synthesis, while mouse slices favored glutamate-to-aspartate conversion.
• Human mitochondria had lower oxygen consumption but higher coupled respiration and lower proton leak with pyruvate/malate, indicating greater efficiency.

Conclusions:

• Significant metabolic differences exist between human and mouse brain cells (neurons and astrocytes).
• These findings highlight the need to consider species-specific metabolic variations when using rodent models for human brain research.