Spatiotemporal Distribution and Function of N-Cadherin in Postnatal Schwann Cells : A Matter of Adhesion?

• During embryonic development of the peripheral nervous system (PNS), the adhesion molecule neuronal cadherin (N-cadherin) is expressed by Schwann cell precursors and associated with axonal growth cones. N-cadherin expression levels decrease as precursors differentiate into Schwann cells. In this study, we investigated the distribution of N-cadherin in the developing postnatal and adult rat peripheral nervous system. N-cadherin was found primarily in ensheathing glia throughout development, concentrated at neuron glial or glial glial contacts of the sciatic nerve, dorsal root ganglia (DRG), and myenteric plexi. In the sciatic nerve, N-cadherin decreases with age and progress of myelination. In adult animals, N-cadherin was found exclusively in nonmyelinating Schwann cells. The distribution of N-cadherin in developing E17 DRG primary cultures is similar to what was observed in vivo. Functional studies of N-cadherin in these cultures, using the antagonist peptide INPISGQ, show a disruption of the attachment between Schwann cells, but no interference in the initial or long-term contact between Schwann cells and axons. We suggest that N-cadherin acts primarily in the adhesion between glial cells during postnatal development. It may form adherents/junctions between nonmyelinating glia, which contribute to the stable tubular structure encapsulating thin caliber axons and thus stabilize the nerve structure as a whole.

Nyckelord

PNS development

nonmyelinating Schwann cells

myelination

enteric glia

satellite cells

MEDICINE

MEDICIN

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