Transient light-induced intracellular oxidation revealed by redox biosensor

Area of Science:

• Cellular Biology
• Biochemistry
• Biophysics

Background:

• Intracellular glutathione redox potential is crucial for cellular health.
• Monitoring real-time redox changes in living cells remains challenging.
• Genetically encoded probes offer a promising avenue for redox sensing.

Purpose of the Study:

• To implement and validate a novel genetically encoded probe, Grx1-roGFP2, for real-time monitoring of intracellular glutathione redox potentials.
• To assess the probe's ability to detect transient changes in cellular redox state, particularly short-lived reactive oxygen species (ROS).

Main Methods:

• Development of a ratiometric, genetically encoded probe by fusing human glutaredoxin (Grx1) to redox-sensitive green fluorescent protein 2 (roGFP2).
• Utilized time-lapse live-cell imaging with short time intervals (<30s) to capture transient cellular events.
• Compared the Grx1-roGFP2 probe with the parental roGFP2 probe lacking Grx1.

Main Results:

• The Grx1-roGFP2 probe successfully monitored real-time intracellular glutathione redox potentials in mammalian cells.
• Short-wavelength excitation triggered media-dependent cytosolic oxidation, detectable with high temporal resolution.
• The enhanced sensitivity of Grx1-roGFP2 enabled the detection of transient, short-lived ROS, which were not observed with the parental roGFP2 probe.
• The probe's high sensitivity also increased its responsiveness to environmental cues, potentially leading to false positives.

Conclusions:

• The Grx1-roGFP2 fusion protein is a highly sensitive tool for detecting short-lived ROS and monitoring cellular redox dynamics in real time.
• The probe's enhanced sensitivity necessitates careful experimental design to mitigate false positive results arising from environmental influences.
• This technology provides a valuable method for advancing our understanding of cellular redox signaling and oxidative stress in living systems.