Automated segmentation and tracking of mitochondria in live-cell time-lapse images

Austin E Y T Lefebvre1,2, Dennis Ma3, Kai Kessenbrock3

  • 1Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, USA.

Nature Methods
|August 20, 2021
PubMed

Insights

Mitometer is a new algorithm for automated segmentation and tracking of mitochondria in live-cell imaging. This tool reveals differences in mitochondrial dynamics and morphology between breast cancer subtypes and links motility to metabolic activity.

Area of Science:

  • Cell Biology
  • Mitochondrial Dynamics
  • Cancer Research

Background:

  • Mitochondria exhibit complex morphology and movement, posing challenges for segmentation and tracking in live-cell imaging.
  • Accurate analysis of mitochondrial dynamics is crucial for understanding cellular function and disease states, particularly in cancer.

Purpose of the Study:

  • To introduce Mitometer, a novel algorithm for automated, unbiased segmentation and tracking of mitochondria in 2D and 3D time-lapse images.
  • To investigate mitochondrial morphology and motility in different breast cancer subtypes and their correlation with metabolic activity.

Main Methods:

  • Developed Mitometer, an algorithm utilizing pixel size and frame interval for mitochondrial identification, including fusion and fission events.
  • Employed shape- and size-preserving background removal for individual mitochondrion segmentation.
  • Implemented a tracking algorithm based on morphological features, displacement, and a gap-closing scheme.

Main Results:

  • Mitometer successfully segmented and tracked mitochondria in live-cell images, identifying motion, morphology, fusion, and fission.
  • Mitochondria in triple-negative breast cancer cells were found to be faster, more directional, and more elongated than in receptor-positive cells.
  • Mitochondrial motility and morphology correlated with metabolic activity in breast cancer cells, but not in normal breast epithelia.

Conclusions:

  • Mitometer provides a fast, unbiased, and user-friendly tool for analyzing mitochondrial dynamics and morphology.
  • The study highlights distinct mitochondrial characteristics in different breast cancer subtypes and their functional relevance.
  • Mitometer facilitates fundamental research into the relationship between mitochondrial form, function, and cancer progression.

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