Microglia and Neonatal Brain Injury. (1st May 2019)

• Record Type: Journal Article
• Authors: Mallard, Carina; Tremblay, Marie-Eve; Vexler, Zinaida S.
• Is Part Of: Neuroscience. Volume 405(2019)
• Page Start: 68
• Page End: 76
• Publication Date: 2019-05-01
• Subjects: ASD autism spectrum disorders -- BBB blood–brain barrier -- Iba1 ionized calcium binding adaptor molecule 1 -- ROS reactive oxidant species -- TGFβ transforming growth factor beta -- TLRs Toll-like receptors -- tMCAO transient middle cerebral artery occlusion; inflammation -- perinatal stroke -- hypoxia-ischemia -- Toll-like receptors -- electron microscopy -- synapse; Neurochemistry -- Periodicals; Neurophysiology -- Periodicals; Neurology -- Periodicals; Neurochimie -- Périodiques; Neurophysiologie -- Périodiques; Neurochemistry; Neurophysiology; Electronic journals; Periodicals; Electronic journals; 612.8
• DOI: 10.1016/j.neuroscience.2018.01.023
• Languages: English
• ISSNs: 0306-4522

Abstract

Graphical abstract: Highlights: Microglial cells guide blood–brain barrier development in embryonic brain. Microglial cells modulate postnatal brain development and brain circuit connectivity. Microglial cells mediate distinct responses in the infectious and sterile inflammatory settings. Microglial cells protect neurovascular integrity in acute perinatal focal arterial stroke. Microglial cells are sexually dimorphic in healthy and in diseased immature brain. Abstract: Microglial cells are now recognized as the "gate-keepers" of healthy brain microenvironment with their disrupted functions adversely affecting neurovascular integrity, neuronal homeostasis, and network connectivity. The perception that these cells are purely toxic under neurodegenerative conditions has been challenged by a continuously increasing understanding of their complexity, the existence of a broad array of microglial phenotypes, and their ability to rapidly change in a context-dependent manner to attenuate or exacerbate injuries of different nature. Recent studies have demonstrated that microglial cells exert crucial physiological functions during embryonic and postnatal brain development, some of these functions being unique to particular stages of development, and extending far beyond sensing dangerous signals and serving as antigen presenting cells. In this focused review we cover the roles of microglial cells in regulating embryonic vasculogenesis, neurogenesis, and establishing network connectivity during postnatal brain development. We further discuss context-dependent microglial contribution to neonatal brain injuries associated with prenatal and postnatal infection and inflammation, in relation to neurodevelopmental disorders, as well as perinatal hypoxia–ischemia and arterial focal stroke. We also emphasize microglial phenotypic diversity, notably at the ultrastructural level, and their sex-dependent influence on the pathophysiology of neurodevelopmental disorders.