Heptamethine Cyanine-Based Molecule Release Triggered by Mitochondrial ROS

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Imaging

Background:

• Mitochondria are key sites for reactive oxygen species (ROS) production.
• Controlled molecule release in cells is crucial for biological studies and therapeutic interventions.
• Current methods for spatiotemporal control of molecular processes in live cells are limited.

Purpose of the Study:

• To develop a novel strategy for ROS-triggered molecule release specifically within mitochondria.
• To create a fluorescent probe for monitoring mitochondrial ROS levels in live cells.
• To investigate the potential of IR-780 as a platform for endogenous ROS-responsive molecular release.

Main Methods:

• Design and synthesis of a dual-targeting molecule (IRTO) by linking a mitochondrial dye (IR-780) and a nuclear dye (NH2-TO).
• Cellular uptake and localization studies of IRTO using fluorescent imaging.
• Investigation of IRTO's response to varying levels of ROS (induced by H2O2, LPS) and ROS inhibitors (NAC, MitoQ).
• Monitoring the spatiotemporal release of NH2-TO from mitochondria to the nucleus.

Main Results:

• IRTO successfully accumulated in mitochondria of live cells, exhibiting red fluorescence.
• Upon reaction with mitochondrial ROS, NH2-TO was released from mitochondria and localized in the nucleus, showing green fluorescence.
• The release of NH2-TO was accelerated by ROS-inducing agents (H2O2, LPS) and inhibited by ROS scavengers (NAC, MitoQ).
• Fluorescence imaging allowed visualization of mitochondrial ROS levels through the sequential red-to-green fluorescence shift.

Conclusions:

• IRTO functions as an effective fluorescent probe for monitoring mitochondrial ROS in live cells.
• The developed strategy demonstrates a viable method for endogenous ROS-triggered molecule release from mitochondria.
• IR-780 shows promise as a core component for developing ROS-responsive molecular platforms for biological applications.