Measuring Intracellular H ₂ O ₂ in Intact Human Cells Using the Genetically Encoded Fluorescent Sensor HyPer7

Area of Science:

• Cell Biology
• Biochemistry
• Biophysics

Background:

• Hydrogen peroxide (H2O2) plays a dual role in cells, acting as a signaling molecule at low concentrations and causing biomolecular damage at high concentrations.
• Cellular H2O2 levels are regulated by production sites, antioxidant systems, and metabolic state, necessitating precise measurement for understanding cellular processes.
• Accurate assessment of subcellular H2O2 dynamics is critical for elucidating its role in cell signaling, but has historically been challenging.

Purpose of the Study:

• To develop and validate a novel method for measuring local hydrogen peroxide (H2O2) dynamics in intact human cells.
• To overcome the limitations of previous H2O2 measurement techniques by utilizing a new generation of genetically encoded sensors.
• To enable high spatiotemporal resolution analysis of H2O2 signaling pathways within cellular environments.

Main Methods:

• Utilized the super-sensitive, pH-independent genetically encoded fluorescent H2O2 sensor, HyPer7.
• Employed a microscopic multi-mode microplate reader for quantitative measurements.
• Applied the method to intact human cells to assess localized H2O2 fluctuations.

Main Results:

• The HyPer7 sensor demonstrated high sensitivity and pH independence, enabling reliable H2O2 detection.
• The combined system allowed for the measurement of H2O2 dynamics with unprecedented spatiotemporal resolution in living cells.
• Successfully demonstrated the capability to track local H2O2 changes within subcellular compartments.

Conclusions:

• The developed method provides a powerful tool for investigating the role of H2O2 in cellular signaling pathways.
• The HyPer7 sensor and microplate reader system overcome previous technical hurdles in H2O2 dynamics measurement.
• This approach facilitates a deeper understanding of redox signaling and cellular responses to oxidative stress.