An Automated, Combined Workflow for Extracting Polar Metabolites and Lipids from Mammalian Cells

Significance of the Topic

Mammalian cell metabolomics and lipidomics rely on robust sample preparation to ensure accurate multi-omic profiling.
Conventional cold quenching and liquid–liquid extraction pose safety and reproducibility challenges.
A streamlined, automated workflow at room temperature addresses these limitations, enhancing lab safety and throughput.

Aims and Study Overview

This study demonstrates an integrated, semi-automated method to concurrently extract polar metabolites and lipids from K562 cell lysates.
It evaluates the efficiency of room temperature quenching with 50% trifluoroethanol (TFE) compared to traditional cold protocols.

Methodology and Instrumentation

• Cell quenching and lysis: 50% TFE at ambient temperature to halt metabolism safely.
• Sequential solid-phase extraction: Captiva EMR-Lipid plate enables separation of metabolites (flow-through) and lipids (eluted fractions).
• Automation: Bravo Liquid Handler executes SPE steps, reducing hands-on time and operator variability.

Used Instrumentation

• Agilent 6545 LC/Q-TOF with ion-pairing reversed-phase for polar metabolites.
• Agilent 6545 LC/Q-TOF in negative-ion mode with Lipid Annotator 1.0 and Mass Profiler Professional 15.1 for lipid analysis.
• MassHunter VistaFlux Software for stable isotope tracing data.

Key Results and Discussion

• Stable isotope tracing with 13C-glutamine showed no artifactual conversion to 13C-glutamate, confirming effective metabolic quenching at room temperature.
• ATP remained stable for at least four hours in 50% TFE, with extraction yields comparable to cold quench methods.
• High recoveries observed for organic acids, amino acids, sugars, and nucleotides, validated by spiked 13C standards.
• Lipid profiling across four replicates yielded 225 annotations in 21 classes, demonstrating extraction consistency relative to traditional workflows.

Benefits and Practical Applications

• Enhanced safety by removing reliance on hazardous cryogens and extreme temperatures.
• Automated SPE reduces manual errors and improves reproducibility in QA/QC and research environments.
• Sequential metabolite and lipid data enable intra-sample multi-omic correlations for comprehensive biological insights.

Future Trends and Possibilities

• Integration with high-throughput platforms for large-scale metabolomics and lipidomics studies.
• Adaptation of room temperature protocols to other cell types and sample matrices.
• Development of universal SPE materials supporting a wider range of analytes in multi-omic workflows.

Conclusion

The presented semi-automated workflow offers a safe, efficient, and reproducible approach for simultaneous extraction of polar metabolites and lipids from mammalian cells at room temperature.
Its compatibility with advanced LC/Q-TOF analytics facilitates comprehensive multi-omic studies, advancing both basic research and industrial applications.

References

• Hartman, T. E., et al. Agilent Technologies Application Note (2017).
• Zhao, L., et al. Agilent Technologies Application Note (2017).
• Matyash, V., et al. Journal of Lipid Research 49, 1137–1146 (2008).