Neuronal Activity Remodels the F-actin Based Submembrane Lattice in Dendrites but not Axons of Hippocampal Neurons

A talk presented by Anthony Bilodeau, Ph.D. student in neurophotonics, concerning how neuronal activity remodels the F-action based submembrane lattice in dendrites, but not axons, of hippocampal neurons – related to a recent publication in Scientific Reports

  • 29 September 2020

15h00 to 16h00



About the talk

The nanoscale organization of the F-actin cytoskeleton in neurons comprises membrane-associated periodical rings, bundles, and longitudinal fibers. The F-actin rings have been observed predominantly in axons but only sporadically in dendrites, where fluorescence nanoscopy reveals various patterns of F-actin arranged in mixed patches. These complex dendritic F-actin patterns pose a challenge for investigating quantitatively their regulatory mechanisms.

We developed here a weakly supervised deep learning segmentation approach of fluorescence nanoscopy images of F-actin in cultured hippocampal neurons. This approach enabled the quantitative assessment of F-actin remodeling, revealing the disappearance of the rings during neuronal activity in dendrites, but not in axons. The dendritic F-actin cytoskeleton of activated neurons remodeled into longitudinal fibers.

We show that this activity-dependent remodeling involves Ca2+  and NMDA receptor-dependent mechanisms. This highly dynamic restructuring of dendritic F-actin based submembrane lattice into longitudinal fibers may serve to support activity-dependent membrane remodeling, protein trafficking and neuronal plasticity.

Speaker : Anthony Bilodeau, Ph.D. candidate in Neurophotonics, Université Laval

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