Extracellular vesicles

Extracellular vesicles (EVs) are spherical structures delimited by a double lipid layer that can be generated by cells and secreted into the extracellular space.

There are various types classes of microvesicles EVs, with different structural and biochemical properties depending on their intracellular origin, likely influencing their function. Those originating from platelets, endothelial cells, and monocytes have been more extensively studied. Platelet-derived microvesicles EVs were initially studied for their procoagulant activity, and recent studies have investigated their involvement in the pathophysiology of vascular disorders.

Moreover, microvesicles EVs are can be released from cell membranes in response to stimuli such as endotoxin, hypoxia, or oxidative stress, cytokine release, and thrombin production, and they might represent one of the means tissues use to adapt to these changes. Microvesicle EV membranes are enriched with characteristic molecules of the parent cell and express adhesion molecules on their surface (e.g., ICAM1), which could promote their capture by recipient cells. The fate of microvesicles EVs after adherence the interaction withto recipient cell surfaces is not known, but recent evidence suggests they may fuse with recipient cell membranes and directly deliver their content into the recipient cell cytoplasm.

It has been hypothesized that microvesicles EVs, after internalization into target cells through surface-expressed ligands, may transfer microRNA (miRNA), allowing intercellular and interorgan communication in the body. Furthermore, the expression of miRNA in circulating microvesicles EVs has been detected in the plasma of healthy subjects, and a predictive role of identified miRNA “signatures” in peripheral blood for diseases has been hypothesized.

References

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