Substrate topography determines neuronal polarization and growth in vitro

Area of Science:

• Neuroscience
• Biophysics
• Developmental Biology

Background:

• Neuronal connectivity relies on precise initial polarization of developing neurons.
• Biophysical cues, such as substrate topography, can influence neuronal morphology and growth in vitro.
• Early differentiation stages, including cell polarization and initial neurite formation, are critical but less understood regarding topographic influences.

Purpose of the Study:

• To investigate the impact of substrate topography on the very early differentiation stages of developing neurons.
• To analyze how micron-sized pillar structures influence neuronal polarization and neurite outgrowth.
• To determine if topographic signaling affects polarization markers and axon extension in early-stage neurons.

Main Methods:

• Fabrication of micron-sized pillar structures with reproducible feature sizes.
• Analysis of mouse embryonic neurons on the interface of flat and topographic surfaces.
• Observation and quantification of polarization markers (N-cadherin, Golgi-centrosome complex) and neurite extension.

Main Results:

• Topographic signaling attracted polarization markers towards the stimuli.
• The Golgi-centrosome complex and the first neurite bud oriented towards topographic cues.
• Axons preferentially extended along the pillars, irrespective of pillar dimensions within the tested range.
• Neurite length showed dependence on pillar dimensions.

Conclusions:

• Substrate topography significantly influences the initial polarization and early neurite outgrowth of developing neurons.
• Topographic cues can guide key cellular components and axon extension during the critical early differentiation phase.
• This study provides detailed insights into the early response of hippocampal neurons to topographic stimuli, highlighting its role in neuronal development.