Burda Joshua E, Bernstein Alexander M, Sofroniew Michael V
Department of Neurobiology and Brain Research Institute, University of California Los Angeles, Los Angeles, CA 90095-1763, USA.
Department of Neurobiology and Brain Research Institute, University of California Los Angeles, Los Angeles, CA 90095-1763, USA.
Exp Neurol. 2016 Jan;275 Pt 3(0 3):305-315. doi: 10.1016/j.expneurol.2015.03.020. Epub 2015 Mar 28.
Astrocytes sense changes in neural activity and extracellular space composition. In response, they exert homeostatic mechanisms critical for maintaining neural circuit function, such as buffering neurotransmitters, modulating extracellular osmolarity and calibrating neurovascular coupling. In addition to upholding normal brain activities, astrocytes respond to diverse forms of brain injury with heterogeneous and progressive changes of gene expression, morphology, proliferative capacity and function that are collectively referred to as reactive astrogliosis. Traumatic brain injury (TBI) sets in motion complex events in which noxious mechanical forces cause tissue damage and disrupt central nervous system (CNS) homeostasis, which in turn trigger diverse multi-cellular responses that evolve over time and can lead either to neural repair or secondary cellular injury. In response to TBI, astrocytes in different cellular microenvironments tune their reactivity to varying degrees of axonal injury, vascular disruption, ischemia and inflammation. Here we review different forms of TBI-induced astrocyte reactivity and the functional consequences of these responses for TBI pathobiology. Evidence regarding astrocyte contribution to post-traumatic tissue repair and synaptic remodeling is examined, and the potential for targeting specific aspects of astrogliosis to ameliorate TBI sequelae is considered.
星形胶质细胞能够感知神经活动和细胞外空间组成的变化。作为响应，它们会发挥对维持神经回路功能至关重要的稳态机制，例如缓冲神经递质、调节细胞外渗透压以及校准神经血管耦合。除了维持正常的脑活动外，星形胶质细胞还会对多种形式的脑损伤做出反应，表现为基因表达、形态、增殖能力和功能的异质性和渐进性变化，这些变化统称为反应性星形胶质细胞增生。创伤性脑损伤（TBI）引发了一系列复杂事件，其中有害的机械力会导致组织损伤并破坏中枢神经系统（CNS）的稳态，进而引发多种随着时间演变的多细胞反应，这些反应可能导致神经修复或继发性细胞损伤。针对TBI，处于不同细胞微环境中的星形胶质细胞会根据轴突损伤、血管破坏、缺血和炎症的不同程度调整其反应性。在此，我们综述了TBI诱导的星形胶质细胞反应性的不同形式以及这些反应对TBI病理生物学的功能影响。我们研究了星形胶质细胞对创伤后组织修复和突触重塑作用的证据，并探讨了针对星形胶质细胞增生的特定方面来改善TBI后遗症的可能性。
