Mapping metabolic dependences and capacities using ATP as a biomarker.

Area of Science:

• Cellular metabolism
• Bioenergetics
• Immunometabolism

Background:

• Metabolic dependences are crucial for cellular energy production.
• Current methods often use surrogate markers, limiting direct assessment of ATP contribution.
• Understanding metabolic shifts is vital for disease and immune cell research.

Purpose of the Study:

• To establish ATP as a direct biomarker for defining metabolic dependences.
• To develop a novel method, MitE-Flo, for quantifying contributions of glycolysis, fatty acid oxidation (FAO), and oxidative phosphorylation (OXPHOS) to cellular ATP.
• To apply this method to study mitochondrial diseases and immunometabolism in germinal center B cells.

Main Methods:

• Development of Mitochondrial/Energy Flow Cytometry (MitE-Flo).
• Evaluation of glycolysis, FAO, and OXPHOS contributions to ATP.
• Analysis of cell populations in mitochondrial disease models and germinal center B cells (light zone/LZ and dark zone/DZ).

Main Results:

• MitE-Flo successfully measured ATP contributions from different metabolic pathways.
• Mitochondrial disease models showed impaired OXPHOS and compensatory glycolysis.
• DZ B cells displayed higher ATP, favoring FAO/OXPHOS, while LZ B cells had lower ATP with balanced glycolysis/OXPHOS.

Conclusions:

• ATP serves as a valuable biomarker for defining metabolic dependences.
• MitE-Flo enhances the understanding of cellular bioenergetics in disease and specific immune cell subtypes.
• This approach provides new tools for metabolism research, particularly in complex cell populations.