Differential intracellular trafficking of extracellular vesicles in microglia and astrocytes.

Abstract

Extracellular vesicles (EVs) have emerged as key players in cell-to-cell communication in both physiological and pathological processes in the Central Nervous System. Thus far, the intracellular pathways involved in uptake and trafficking of EVs within different cell types of the brain are poorly understood. In our study, the endocytic processes and subcellular sorting of EVs were investigated in primary glial cells, particularly linked with the EV-associated α-synuclein (α-syn) transmission. Mouse microglia and astrocytic primary cultures were incubated with DiI-stained mouse brain-derived EVs. The internalization and trafficking pathways were analyzed in cells treated with pharmacological reagents that block the major endocytic pathways. Brain-derived EVs were internalized by both glial cell types; however, uptake was more efficient in microglia than in astrocytes. Colocalization of EVs with early and late endocytic markers (Rab5, Lamp1) indicated that EVs are sorted to endo-lysosomes for subsequent processing. Blocking actin-dependent phagocytosis and/or macropinocytosis with Cytochalasin D or EIPA inhibited EV entry into glial cells, whereas treatment with inhibitors that strip cholesterol off the plasma membrane, induced uptake, however differentially altered endosomal sorting. EV-associated fibrillar α-Syn was efficiently internalized and detected in Rab5- and Lamp1-positive compartments within microglia. Our study strongly suggests that EVs enter glial cells through phagocytosis and/or macropinocytosis and are sorted to endo-lysosomes for subsequent processing. Further, brain-derived EVs serve as scavengers and mediate cell-to-glia transfer of pathological α-Syn which is also targeted to the endolysosomal pathway, suggesting a beneficial role in microglia-mediated clearance of toxic protein aggregates, present in numerous neurodegenerative diseases.

• Authors: Marina Pantazopoulou, Agaristi Lamprokostopoulou, Dimitra Sotiria Karampela, Anastasia Alexaki, Anastasios Delis, Audrey Coens, Martina Samiotaki, Anastasios G Kriebardis, Ronald Melki, Stamatis N Pagakis, Leonidas Stefanis, Kostas Vekrellis
• Journal: Cellular and molecular life sciences : CMLS (Cell Mol Life Sci) Vol. 80 Issue 7 Pg. 193 (Jun 30 2023) ISSN: 1420-9071 [Electronic] Switzerland
• PMID: 37391572 (Publication Type: Journal Article)
• Copyright: © 2023. The Author(s).

Topics

• Animals
• Mice
• Female
• Humans
• Astrocytes
• Microglia
• Neuroglia
• Central Nervous System
• Biological Transport
• Endometriosis