Trends in Neurosciences
ReviewAstrocytes and Microglia: In Sickness and in Health
Section snippets
The Bond between Astrocytes and Microglia
Like many great duos, astrocytes and microglia in the central nervous system (CNS) have a unique bond that constrains and coordinates their functions. The brain is functionally dominated by its most specialized cell type, neurons, electrically active cells evolved for intercellular communication. Yet, as in other organs, brain function depends on a village of cell types whose functions are relatively conserved across multiple tissues, including vascular endothelial cells, pericytes, and
Astrocytes and Microglia Promote Developmental Synapse Formation and Pruning
Both astrocytes and microglia play critical roles in neural circuit formation during development, particularly in support of synapse formation and remodeling. Astrocytes surround and contact most neuronal synapses, as well as forming the borders of the brain and vasculature. Studies over the past two decades have identified multiple molecules released from astrocytes that promote neuronal synapse formation. These include glypicans 4 and 6, thrombospondin 1 and 2, and hevin (Sparcl1) (reviewed
Molecular Mechanisms of Astrocyte Microglial Communication in Pathology
Recent work has begun to reveal several molecular mechanisms by which astrocyte and microglial function is synchronized and, more often than not, these mechanisms are studied in the context of pathology. In the sections below, we will review some of the signaling molecules that coordinate the function of astrocytes and microglia across a range of perturbations (Figure 3). We focus on selected examples where recent literature indicates direct interactions between astrocytes and microglia, or
Concluding Remarks
Recent advances in single-cell analysis have changed the landscape of science and have the potential to reveal synchronized responses among multiple cell types in the brain. Single-cell data has already opened up new approaches to understanding microglia and revealed novel microglial and myeloid subsets in inflammatory conditions, including a disease associated microglial signature that may be conserved in several different pathologies [63., 64., 65.,110]. This subset represented 7% of cells in
Acknowledgments
Thanks to Ari Molofsky and members of the Anna Molofsky lab for helpful discussion and comments on the manuscript and to funding from NIMH (R01 MH119349), the Pew Charitable Trusts, and the Burroughs Wellcome Fund.
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