The Heterogeneity and Phenotypic Diversity of Astrocytes and Microglia in Disease and Injury

It is now well accepted that glia causally contribute to the pathology of central nervous system (CNS) injuries, as well as the pathogenesis and progression of CNS diseases. Astrocytes, the most abundant glia in the CNS, and microglia, the resident macrophages and innate immune cells of the brain and spinal cord, have emerged as key players in CNS physiology and pathophysiology. Increasing evidence indicates that both astrocytes and microglia exhibit significant functional, molecular, transcriptional and morphological heterogeneity, which is CNS region- and context-dependent. Under the influence of stimuli present in the milieu of the injured or diseased CNS, astrocytes become reactive and microglia get activated. Depending on the factors present in the affected region(s), reactive astrocytes and activated microglia can acquire either beneficial or detrimental phenotypes, which are essential determinants of the paradoxical role played by glia in pathological conditions. Fostering the neuroprotective, reparative and restorative potential of glia, while inhibiting their deleterious effects could improve the outcomes of injury and diseases. This necessitates a thorough understanding of astrocyte and microglia diversity in the healthy CNS and how this diversity is affected in various CNS regions, in a disease- or injury-specific manner.

The aim of this Research Topic is to highlight the complex diversity of astrocytes and microglia and its impact on the function or dysfunction of neural circuits, neurons and glia in the CNS. Advances in the discovery of astrocyte and microglia diversity could facilitate the design of targeted therapeutic strategies to improve the outcomes of CNS pathologies.

For this Research Topic, we invite original articles and reviews in the research areas including but not limited to
-The ontogeny of astrocyte and microglia heterogeneity.
- The regional characteristics of astrocytes and microglia in the healthy, aging, diseased and injured CNS.
- Intra-regional diversity of astrocyte and microglia subpopulations.
- The impact of astrocyte and microglia heterogeneity on the function or dysfunction of specific neuronal circuits in the CNS.
- The disease-specific properties and functional diversity of astrocytes and microglia in neurodegenerative and inflammatory diseases, psychiatric and mood disorders, brain and spinal cord injuries, developmental disorders of the CNS, neuropathic pain and other CNS pathologies.
- Commonalties in the determinants of the phenotypic and functional diversity of astrocytes and microglia across different CNS pathologies.