Microglia ‐derived extracellular vesicles in homeostasis and demyelination/remyelination processes

Microglia (MG) monitor the brain parenchyma and detect danger signals in a surveillance state. This state is maintained through interactions with neurons mediated by CD200-CD200R, CD47-CD172a, and fractalkine-CX3CR1. Neuroinflammation, mediated by cytokines released by Th1/Th17 cells or by extracellular vesicles (EVs) derived from other peripheral inflammatory cells, can activate MG to an M1 state. M1 MG release EVs containing pro-inflammatory cytokines and toxic metabolites which promote an A1 astroglial phenotype and induce demyelination. MG can also be activated to a pro-regenerative M2 state and release EVs capable of increasing neuronal survival and inducing the recruitment, migration, and differentiation of oligodendroglial progenitors which facilitate remyelination. AbstractMicroglia (MG) play a crucial role as the predominant myeloid cells in the central nervous system and are commonly activated in multiple sclerosis. They perform essential functions under normal conditions, such as actively surveying the surrounding parenchyma, facilitating synaptic remodeling, engulfing dead cells and debris, and protecting the brain against infectious pathogens and harmful self-proteins. Extracellular vesicles (EVs) are diverse structures enclosed by a lipid bilayer that originate from intracellular endocytic trafficking or the plasma membrane. They are released by cells into the extracellular space and can be found in various bodily fluids. EVs have recently emerged as a communica...
Source: Journal of Neurochemistry - Category: Neuroscience Authors: Tags: REVIEW Source Type: research