Blood vessels guide Schwann cell migration in the adult demyelinated CNS through Eph/ephrin signaling

Abstract

ABSTRACTSchwann cells (SC) enter the central nervous system (CNS) in pathophysiological conditions. However, how SC invade the CNS to remyelinate central axons remains undetermined. We studied SC migratory behaviorex vivoandin vivoafter exogenous transplantation in the demyelinated spinal cord. Data highlight for the first time that SC migrate preferentially along blood vessel in perivascular ECM, avoiding CNS myelin. We demonstratein vitroandin vivothat this migration route occurs by virtue of a dual mode of action of Eph/ephrin receptor. Indeed, EphrinB3, enriched in myelin, interacts with SC Eph receptors, to drive SC away from CNS myelin, and triggers their preferential adhesion to ECM components, such as fibronectin via integrinβ1 interactions. This complex interplay enhances SC migration along the blood vessel network and together with lesion-induced vascular remodeling facilitates their timely invasion of the lesion site. These novel findings elucidate the mechanism by which SC invade and contribute to spinal cord repair.