【Seminar】The Ghost Neuron Protocol for Integrative Structural Analysis of CNS Axons by Dr. Christian Biertuempfel, National Heart, Lung, and Blood Institute

Title: The Ghost Neuron Protocol for Integrative Structural Analysis of CNS Axons

Speaker: Dr. Christian Biertuempfel

National Heart, Lung, and Blood Institute (NHLBI/NIH)

Abstract

Cellular cryo-electron microscopy (cryo-EM) offers powerful tools to reveal molecular architecture inside cells, but the dense cytoplasm often obscures fine molecular features, especially in narrow neuronal projections. While studying epothilone B-induced axonal regeneration in primary moues CNS neurons we realized that careful specimen preparation can provide an additional edge into cryo-EM imaging. We developed the Ghost Neuron technique, a preparation combining brief hypotonic treatment with controlled mechanical rupture immediately before freezing, facilitating high-contrast imaging of neuronal ultrastructure within its neurite topology. 

By removing the plasma membrane and reducing cytoplasmic density, the method allows high-resolution structural analysis while preserving the overall geometry of neurites. Moreover, structural information can be mapped back onto the neuronal architecture. Using the Ghost Neuron approach, we resolved axonal microtubules distinguishing expanded and compact lattice states and mapped these states as interspersed patches along individual microtubules within axons. We also resolved axonal actin filaments and identified cofilin-decorated actin. These results establish Ghost Neuron as a discovery platform for linking molecular structure to neuronal organization.