Single-Particle Tracking Method in Fluorescence Microscopy to Monitor Bioenergetic Responses of Individual...

Area of Science:

• Mitochondrial bioenergetics
• Cellular biology
• Biophysics

Background:

• Current spectroscopic methods lack resolution for individual mitochondrial responses.
• Studying mitochondrial dynamics and the mitochondrial permeability transition pore (mPTP) requires improved methodologies.
• Heterogeneity in mitochondrial function within populations remains largely uncharacterized.

Purpose of the Study:

• To develop and validate a novel high-resolution method for analyzing single mitochondrion responses.
• To enable quantitative and kinetic analysis of individual mitochondrial dynamics in large populations.
• To provide a foundation for studying the role of mPTP in single mitochondria.

Main Methods:

• Isolation of mitochondria from cardiomyocytes.
• Loading mitochondria with TMRM (tetramethylrhodamine, a membrane potential-sensitive dye).
• High-throughput fluorescence microscopy with automated image analysis using TrackMate-ImageJ and Python scripts.
• Signal-to-noise ratio enhancement and individual mitochondrion tracking with 400 ms time resolution.

Main Results:

• Simultaneous monitoring of thousands of individual mitochondria with single-organelle resolution.
• Significant improvement in signal-to-noise ratio (over two orders of magnitude).
• Uninterrupted tracking of mitochondrial fluorescence changes over experimental time.

Conclusions:

• The developed method offers unprecedented resolution for studying mitochondrial bioenergetics at the single-organelle level.
• This technique is crucial for understanding mitochondrial heterogeneity and dynamics.
• It serves as a prerequisite for investigating the mitochondrial permeability transition pore (mPTP) in single mitochondria during dynamic cellular events.