title: The biphasic function of microglia in ischemic stroke.
abstract: Microglia are brain resident macrophages originated from primitive progenitor cells in the yolk sac. Microglia can be activated within hours and recruited to the lesion site. Traditionally, microglia activation is considered to play a deleterious role in ischemic stroke, as inhibition of microglia activation attenuates ischemia induced brain injury. However, increasing evidence show that microglia activation is critical for attenuating neuronal apoptosis, enhancing neurogenesis, and promoting functional recovery after cerebral ischemia. Differential polarization of microglia could likely explain the biphasic role of microglia in ischemia. We comprehensively reviewed the mechanisms involved in regulating microglia activation and polarization. The latest discoveries of microRNAs in modulating microglia function are discussed. In addition, the interaction between microglia and other cells including neurons, astrocytes, oligodendrocytes, and stem cells were also reviewed. Future therapies targeting microglia may not exclusively aim at suppressing microglia activation, but also at modulating microglia polarization at different stages of ischemic stroke. More work is needed to elucidate the cellular and molecular mechanisms of microglia polarization under ischemic environment. The roles of microRNAs and transplanted stem cells in mediating microglia activation and polarization during brain ischemia also need to be further studied.
authors: Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China; Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
authors: Yuanyuan
authors: Y
authors: Ma
authors: Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China; Department of Rehabilitation, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China.
authors: Jixian
authors: J
authors: Wang
authors: Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address: ytwang@sjtu.edu.cn.
authors: Yongting
authors: Y
authors: Wang
authors: Department of Neurology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200025, China; Neuroscience and Neuroengineering Research Center, Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China. Electronic address: gyyang0626@163.com.
authors: Guo-Yuan
authors: GY
authors: Yang
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D017628:Microglia / Q000502:physiology* / Q000637:transplantation; D020521:Stroke / Q000503:physiopathology* / Q000628:therapy
keywords: Crosstalk; Ischemic stroke; Microglia; Polarization; microRNAs