A role for ephrin-A5 in axonal sprouting, recovery, and activity-dependent plasticity after stroke.
Stroke causes loss of neurological function. Recovery after stroke is facilitated by forced use of the affected limb and is associated with sprouting of new connections, a process that is sharply confined in the adult brain. We show that ephrin-A5 is induced in reactive astrocytes in periinfarct cortex and is an inhibitor of axonal sprouting and motor recovery in stroke. Blockade of ephrin-A5 signaling using a unique tissue delivery system induces the formation of a new pattern of axonal projections in motor, premotor, and prefrontal circuits and mediates recovery after stroke in the mouse through these new projections. Combined blockade of ephrin-A5 and forced use of the affected limb promote new and surprisingly widespread axonal projections within the entire cortical hemisphere ipsilateral to the stroke. These data indicate that stroke activates a newly described membrane-bound astrocyte growth inhibitor to limit neuroplasticity, activity-dependent axonal sprouting, and recovery in the adult.
Pubmed ID: 22837401 RIS Download
Animals | Astrocytes | Axons | Behavior, Animal | Cerebral Cortex | Ephrin-A5 | Mice | Mice, Inbred C57BL | Motor Activity | Nerve Net | Neuronal Plasticity | Phosphorylation | Recovery of Function | Signal Transduction | Staining and Labeling | Stroke