Laminin 332 regulates glial fibrillary acidic protein expression and astrocyte maturation during spinal cord development.

The white matter of the spinal cord is essential for sensory and motor signaling, and its proper development is crucial for establishing functional neuronal circuits. However, the mechanisms underlying white matter formation remain incompletely understood. We hypothesized that the extracellular matrix, particularly laminins, plays a key role in this process. The spatiotemporal expression patterns of laminins during spinal cord white matter development have not been fully characterized. Here, we examined the distribution and function of laminins during spinal cord development. Laminin 332 localized to the marginal zone of the spinal cord at embryonic days 12 (E12) and 14 (E14), coinciding with periods of extensive axonal growth. Immunohistochemical analysis revealed an increase in glial fibrillary acidic protein (GFAP)-positive fibers in laminin 332-enriched regions. Laminin 332 promoted GFAP expression in astrocyte precursor cells, an effect attenuated by integrin α6β4 blockade, suggesting that laminin 332 signals through integrins to support astrocyte maturation. Our findings indicate that laminin 332 not only serves as a structural component of the extracellular matrix but also actively regulates glial differentiation during spinal cord development. Understanding the signaling pathways mediated by laminin 332 may inform therapeutic strategies aimed at enhancing spinal cord regeneration by modulating astrocyte behavior and promoting axonal growth.