RAGE-TXNIP axis is required for S100B-promoted Schwann cell migration, fibronectin expression and cytokine secretion.

ABSTRACT

During peripheral nerve injury, Schwann cells (SCs) adopt a migratory phenotype and remodel the extracellular matrix and provide a supportive activity for neuron regeneration. SCs synthesize neurotrophic factors and cytokines that are crucial for the repair of the injured nerve. The receptor for advanced glycation end products (RAGE) and its ligand S100B, which are secreted by SCs, are required for the repair of the injured peripheral nerve in vivo. However, the precise intracellular pathways involved have not been completely elucidated. Here, we show that RAGE-induced S100B secretion involves the recruitment of S100B in lipid rafts and caveolae. Moreover, we demonstrate for the first time that RAGE induces the expression of thioredoxin interacting protein (TXNIP) in SCs and the injured sciatic nerve in vivo. TXNIP is involved in the activation of p38 MAPK, CREB and NFκB in SCs. TXNIP silencing partially inhibits RAGE-induced SC migration and completely abolishes RAGE-induced fibronectin and IL-1ß expression. Our results support a model in which TXNIP mediates in part RAGE-induced SC migration and is required for the expression of provisional ECM and pro-inflammatory IL-1ß. We provide new insight on the role of the SC RAGE-TXNIP axis in the repair of injured peripheral nerves.