Schwann cells (SCs) encase peripheral axons with insulating myelin sheaths to enable faster conduction and promote regeneration following nerve injury by helping clear axonal debris and guiding regrowth. These processes are difficult to study in vitro due to challenges with inducing myelination in SCs under conditions that are compatible with purified neuronal cultures, especially in cells from mice; this has limited the use of many existing transgenic mouse models and established genetic tools for assaying peripheral nerve repair in vitro. In this Tools and Resources (Mutschler et al., 2023), Peter Arthur-Farraj and colleagues develop a compartmentalised coculture platform using microfluidic chambers that enables robust myelination of mouse dorsal root ganglion (DRG) axons by mouse SCs. The authors show that cocultured SCs can recapitulate the processes known to occur in vivo following peripheral nerve injury, such as demyelination of degenerating axons, phagocytosis of axonal fragments and upregulation of the transcription factor JUN. Using this system, they demonstrate that SCs reduce DRG axon degeneration after injury in vitro regardless of myelination status, suggesting that this known protective function of SCs might be independent of myelin sheath formation. This refined coculture platform offers new opportunities to test cells from transgenic mouse lines, gene expression vectors and pharmacological interventions in an in vitro peripheral nerve injury system.
