MitoTNT: Mitochondrial Temporal Network Tracking for 4D live-cell fluorescence microscopy data

Area of Science:

• Cell Biology
• Mitochondrial Dynamics
• Bioimaging

Background:

• Mitochondria form a dynamic 4D network crucial for cellular health.
• Dysregulation of mitochondrial networks is linked to diseases like cancer and neurodegeneration.
• Existing 4D imaging methods lack quantitative analysis tools for mitochondrial networks.

Purpose of the Study:

• Introduce MitoTNT, the first software for Mitochondrial Temporal Network Tracking (MitoTNT) in 4D live-cell microscopy.
• Provide accurate quantitative analysis of mitochondrial network dynamics.
• Facilitate research into mitochondrial roles in health and disease.

Main Methods:

• Developed MitoTNT software utilizing spatial proximity and network topology for optimal tracking.
• Validated tracking accuracy using reaction-diffusion simulations and experimental data.
• Applied MitoTNT to quantify 4D mitochondrial networks in human induced pluripotent stem cells.

Main Results:

• MitoTNT achieved >90% accuracy in simulations and validated well with experimental data.
• Characterized mitochondrial skeleton node motion, revealing temporal correlations.
• Identified fission/fusion events, showing increased node motility near these sites and a role for microtubules.
• Transport simulations revealed that pharmacological perturbations affect network reachability and resilience.

Conclusions:

• MitoTNT provides accurate, accessible 4D mitochondrial network tracking and analysis.
• Revealed novel insights into mitochondrial dynamics, including node motion patterns and fission/fusion mechanisms.
• Demonstrated the impact of perturbations on mitochondrial network function, relevant for disease and drug development.