Optimized laminin surfaces induce spontaneous myelination by neonate mice dorsal root ganglia

Peripheral nervous system myelination requires tightly coordinated structural and calcium-dependent communication between sensory axons and Schwann cells, processes that are profoundly influenced by extracellular matrix architecture. Here we describe a neonatal mouse dorsal root ganglia explant co-culture grown on laminin-1 pre-polymerized in acidic acetate buffer at pH 4 (polylaminin). This optimized substrate induced spontaneous formation of MBP-positive myelin sheaths, accompanied by enhanced alignment of Schwann cells with neurite bundles. Polylaminin also promoted robust clustering of the neuregulin receptor ErbB2 and a substantial increase in Connexin-43 gap-junction clusters along Schwann cell processes compared with laminin assembled in neutral phosphate buffer at pH 7 or with Poly-l-lysine. Fura-2 calcium imaging demonstrated that cultures on polylaminin exhibited faster, larger, and more sustained Ca²⁺ transients after KCl depolarization and ATP stimulation, indicating superior neuron-glia coupling and excitability. In contrast, laminin at pH 7 preferentially supported neurite outgrowth and Schwann cell migration, whereas Poly-l-lysine showed limited organization and responsiveness. The study establishes a simple and reproducible in vitro platform in which laminin supramolecular organization directs DRG cells toward neuritogenic or myelinating phenotypes through integrin/FAK/AKT signaling. By reducing the complexity of myelin induction while preserving functional communication, this model offers a valuable tool to investigate early events of peripheral demyelination, Cx43-dependent dysfunction, and degenerative responses characteristic of neuropathies that often precede CNS involvement.