Using Stable Isotopes in Bone Marrow Derived Macrophage to Analyze Metabolism

Area of Science:

• Metabolomics
• Biochemistry
• Systems Biology

Background:

• The citric acid cycle (CAC) is central to energy metabolism, but its complex regulation and interplay with other pathways remain incompletely understood.
• Analyzing CAC intermediates can uncover unexpected correlations between metabolic pathways, offering insights into cellular energy production.
• Gas chromatography-mass spectrometry (GC-MS) is a powerful technique for quantifying metabolites and tracing metabolic flux.

Purpose of the Study:

• To present a sensitive GC-MS protocol for analyzing CAC intermediates and related metabolites.
• To demonstrate the utility of this protocol for assessing metabolic pathway integrity and flux.
• To investigate the role of phosphoenolpyruvate carboxykinase 1 (Pck1) in mouse macrophage energy metabolism using labeled glucose tracers.

Main Methods:

• Utilized gas chromatography-mass spectrometry (GC-MS) for the quantitative analysis of citric acid cycle (CAC) intermediates and related metabolites.
• Employed stable isotope labeling (¹³C-labeled glucose) to trace metabolic flux and determine precursor contributions to CAC metabolite pools.
• Applied the developed GC-MS protocol to study the role of the Pck1 gene in mouse macrophage cells.

Main Results:

• The GC-MS protocol demonstrated sensitivity for detecting small concentrations of metabolic intermediates.
• ¹³C-labeling enabled the assessment of precursor contributions from glucose to specific CAC metabolite pools.
• The study provided insights into the role of Pck1 in regulating metabolic flux within macrophage cells.

Conclusions:

• GC-MS is a versatile and sensitive method for analyzing metabolic pathways, including the CAC.
• Stable isotope tracing combined with GC-MS allows for the elucidation of metabolic flux and pathway dynamics.
• This approach facilitates the investigation of gene function in metabolic regulation under various physiological and pathological conditions.