Mitochondrial network complexity emerges from fission/fusion dynamics

Area of Science:

• Cell Biology
• Systems Biology
• Biophysics

Background:

• Mitochondrial networks display complex behaviors like energy oscillations and stress-induced depolarization.
• The structure of mitochondrial networks is closely linked to their function.
• Understanding mitochondrial network structure is crucial for comprehending cellular energy homeostasis and stress responses.

Purpose of the Study:

• To characterize the structure of mitochondrial networks in mouse embryonic fibroblasts using network analysis and percolation theory.
• To investigate how mitochondrial network structure is affected by perturbations in fission and fusion dynamics.
• To compare empirical findings with computational models of mitochondrial network emergence.

Main Methods:

• Utilized network tools and percolation theory to analyze mitochondrial network structure in mouse embryonic fibroblasts.
• Perturbed mitochondrial dynamics by promoting fusion or inducing fission.
• Performed quantitative analysis of mitochondrial clusters and compared results with a computational model based on fission-fusion kinetics.

Main Results:

• The structural parameters of healthy mitochondria were found to lie between highly fragmented and completely fused network extremes.
• Empirical findings aligned with predictions from a computational model of mitochondrial network emergence.
• Demonstrated that mitochondrial networks exhibit critical system behavior and undergo structural phase transitions.

Conclusions:

• Developed an objective methodology to quantify the complexity of mitochondrial networks.
• Provided evidence that mitochondrial networks behave as critical systems.
• Supported the concept of structural phase transitions in mitochondrial networks under physiological and stressed conditions.