Fluorogenic and Mitochondria-Localizable Probe Enables Selective Labeling and Imaging of Nitroreductase

Area of Science:

• Biochemistry
• Chemical Biology
• Molecular Imaging

Background:

• Nitroreductase (NTR) is a flavin-dependent enzyme upregulated under tumor hypoxia.
• Existing fluorescent probes for NTR activity suffer from diffusion, limiting accuracy and signal quality.
• Accurate localization and sensitive detection of NTR are crucial for biological studies.

Purpose of the Study:

• To design, synthesize, and evaluate a novel NTR-activatable probe (FY) for enhanced biological imaging.
• To develop a probe that overcomes the diffusion limitations of conventional fluorescent probes.
• To enable permanent labeling and high-resolution imaging of NTR activity.

Main Methods:

• Design and synthesis of the FY probe.
• Integration of quinone methide (QM) proximity-based protein labeling.
• In vitro evaluation of probe performance, including localization and retention.
• Biological applications for imaging NTR activity in cells.

Main Results:

• The FY probe exhibits mitochondrial localization and a fluorogenic response.
• FY achieves permanent retention at the NTR activation site, preventing diffusion.
• Enhanced spatial resolution and improved detection sensitivity were observed, even after cell fixation.
• The probe demonstrated successful biological applications in imaging complex biological events.

Conclusions:

• The FY probe offers a significant advancement over conventional NTR detection methods.
• Permanent labeling by FY enhances accuracy and signal-to-noise ratio for NTR imaging.
• This work provides a versatile synthetic strategy for developing permanent labeling fluorescence probes.