Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.
Proc Natl Acad Sci U S A. 2012 Aug 14;109(33):E2230-9. doi: 10.1073/pnas.1204386109. Epub 2012 Jul 25.
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.
中风会导致神经功能丧失。中风后,通过强制使用受影响的肢体来促进恢复,并且与新连接的萌发有关,这个过程在成人的大脑中受到严格限制。我们表明,ephrin-A5 在梗塞周围皮质的反应性星形胶质细胞中被诱导,并且是中风中轴突萌发和运动恢复的抑制剂。使用独特的组织传递系统阻断 Ephrin-A5 信号会诱导运动、前运动和前额叶回路中轴突投射的新模式形成,并通过这些新投射介导中风后的恢复。Ephrin-A5 和强制使用受影响肢体的联合阻断促进了中风对侧整个大脑半球中令人惊讶的广泛的轴突投射。这些数据表明,中风激活了一种新描述的膜结合星形胶质细胞生长抑制剂,以限制成年动物的神经可塑性、活性依赖的轴突萌发和恢复。