The functional role of soluble proteins acquired by extracellular vesicles

Abstract

Extracellular vesicles (EVs) are lipid bilayer‐enclosed nanosized particles released by all cell types during physiological as well as pathophysiological processes to carry out diverse biological functions, including acting as sources of cellular dumping, signalosomes and mineralisation nanoreactors. The ability of EVs to perform specific biological functions is due to their biochemical machinery. Among the components of the EVs’ biochemical machinery, surface proteins are of critical functional significance as they mediate the interactions of EVs with components of the extracellular milieu, the extracellular matrix and neighbouring cells. Surface proteins are thought to be native, that is, pre‐assembled on the EVs’ surface by the parent cells before the vesicles are released. However, numerous pieces of evidence have suggested that soluble proteins are acquired by the EVs’ surface from the extracellular milieu and further modulate the biological functions of EVs during innate and adaptive immune responses, autoimmune disorders, complement activation, coagulation, viral infection and biomineralisation. Herein, we will describe the methods currently used to identify the EVs’ surface proteins and discuss recent knowledge on the functional relevance of the soluble proteins acquired by EVs.

Extracellular Vesicles from Highly Metastatic Osteosarcoma Cells Induce Pro‐Tumorigenic Macrophage Phenotypes

“…[ 63 ] Though both miRNA and protein payloads can be differentially expressed in highly metastatic OS‐EVs, [ 64 ] our data suggests that this signal is transduced externally. This indicates membrane proteins, adsorbed nucleic acids, or other adsorbed molecules [ 65 ] may play a role.…”

Unravelling the relationship between isolated bone matrix vesicles and forming mineral at the nanometer scale

“…It is important to note that non-vesicular components should not always be considered as contaminants. It has already been reported that the formation of a corona acquired from the extracellular milieu, composed by soluble proteins at the surface of extracellular vesicles can regulate and direct their function 65 . Proteoglycans, collagens, and non-collagenous proteins have been reported to be present in MVs preparations 66 , and the coexistence of MVs with these components within the extracellular matrix, has been long recognized at the ultrastructural level 67 .…”

Extracellular vesicles and their cells of origin: Open issues in autoimmune diseases

“…-It is possible for EVs to acquire soluble proteins from the surrounding extracellular milieu (200)(201)(202).…”

“…The main determinants are the physical and biochemical characteristics of their surface and protein concentration-based environmental changes. For example, during the pathogenesis of autoimmune diseases and innate and acquired immune responses, autoantigens may be packaged in EVs prior to or post-release (200)(201)(202).…”