Probing Methionine Uptake in Live Cells by Deuterium Labeling and Stimulated Raman Scattering

Area of Science:

• Chemical Biology
• Biomedical Imaging
• Cellular Metabolism

Background:

• Methionine (Met) is a crucial amino acid involved in protein synthesis, cancer metabolism, and epigenetics.
• Visualizing the subcellular distribution of small biomolecules like Met non-invasively remains a challenge.
• Previous methods using alkyne-labeled analogues have limitations in imaging sensitivity and invasiveness.

Purpose of the Study:

• To demonstrate stimulated Raman scattering (SRS) imaging for visualizing the cellular uptake of deuterated methionine (d8-Met).
• To compare the efficacy of d8-Met imaging with a previously used analogue, homopropargylglycine (Hpg).
• To establish d8-Met as a tool for minimally invasive investigation of metabolic processes at subcellular resolution.

Main Methods:

• Utilized stimulated Raman scattering (SRS) microscopy for live-cell imaging.
• Compared the SRS signal intensity and cellular uptake of deuterated methionine (d8-Met) against homopropargylglycine (Hpg).
• Employed background subtraction techniques for enhanced image analysis and signal quantification.

Main Results:

• d8-Met and Hpg exhibited similar SRS signal intensities in solution.
• SRS imaging successfully visualized cellular uptake of d8-Met with significantly greater signal intensity than Hpg.
• The enhanced signal suggests potentially increased and less invasive uptake kinetics for d8-Met.

Conclusions:

• Deuterated methionine (d8-Met) is a viable and effective tracer for SRS imaging of cellular uptake.
• d8-Met offers superior signal intensity and potentially improved uptake kinetics compared to Hpg.
• Deuterated biomolecules show promise for high-resolution, minimally invasive studies of metabolic pathways.