A directional 3D neurite outgrowth model for studying motor axon biology and disease

We report a method to generate a 3D motor neuron model with segregated and directed axonal outgrowth. iPSC-derived motor neurons are cultured in extracellular matrix gel in a microfluidic platform. Neurons extend their axons into an adjacent layer of gel, whereas dendrites and soma remain predominantly in the somal compartment, as verified by immunofluorescent staining. Axonal outgrowth could be precisely quantified and was shown to respond to the chemotherapeutic drug vincristine in a highly reproducible dose-dependent manner. The model was shown susceptible to excitotoxicity upon exposure with excess glutamate and showed formation of stress granules upon excess glutamate or sodium arsenite exposure, mimicking processes common in motor neuron diseases. Importantly, outgrowing axons could be attracted and repelled through a gradient of axonal guidance cues, such as semaphorins. The platform comprises 40 chips arranged underneath a microtiter plate providing both throughput and compatibility to standard laboratory equipment. The model will thus prove ideal for studying axonal biology and disease, drug discovery and regenerative medicine.

Automated summary

This study presents a method to generate a 3D motor neuron model with segregated and directed axonal outgrowth, where axons extend into an adjacent layer of gel while dendrites and soma are predominantly in the somal compartment. The model shows reproducible responses to chemotherapeutic drugs and excitotoxicity, making it ideal for studying axonal biology and diseases, drug discovery, and regenerative medicine. The platform allows for attraction and repulsion of axons through a gradient of axonal guidance cues, providing a versatile tool for neuroscientific research.