Contribution of cytoskeletal elements to the axonal mechanical properties

Area of Science:

• Neuroscience
• Cell Biology
• Biophysics

Background:

• Cytoskeletal elements like microtubules, microfilaments, and neurofilaments are crucial for neural cell morphology, function, and mechanical integrity.
• Understanding the distinct mechanical contributions of these elements is vital for comprehending axon development and function.

Purpose of the Study:

• To determine the specific contribution of microtubules, microfilaments, and neurofilaments to the mechanical properties of axons.
• To investigate the mechanical stiffness of axons in dorsal root and sympathetic ganglia cells from chick embryos.

Main Methods:

• Axons were treated with specific inhibitors (nocodazole, cytochalasin D, acrylamide) to selectively disrupt microtubules, microfilaments, and neurofilaments.
• Atomic Force Microscopy (AFM) was employed to compress treated axons and measure force-deformation responses.
• Analysis of force-deformation data allowed for the estimation of mechanical properties in disrupted axons.

Main Results:

• Disruption of microtubules led to the most significant reduction in axonal mechanical stiffness.
• Axons with disrupted neurofilaments showed a moderate decrease in stiffness.
• Disruption of microfilaments resulted in the least pronounced reduction in axonal stiffness.

Conclusions:

• Microtubules are the primary determinant of mechanical stiffness in axons.
• The findings highlight the differential contribution of cytoskeletal components to neuronal mechanical properties.
• This research provides insights into the structural mechanics of axons and their dependence on specific cytoskeletal networks.