Extracellular vesicles including exosomes are mediators of signal transduction: Are they protective or pathogenic?

Abstract

Extracellular vesicles are signaling organelles that are released by many cell types and is highly conserved in both prokaryotes and eukaryotes. Based on the mechanism of biogenesis, these membranous vesicles can be classified as exosomes, shedding microvesicles and apoptotic blebs. It is becoming clearer that these extracellular vesicles mediate signal transduction in both autocrine and paracrine fashion by the transfer of proteins and RNA. Whilst the role of extracellular vesicles including exosomes in pathogenesis is well established, very little is known about their function in normal physiological conditions. Recent evidences allude that extracellular vesicles can mediate both protective and pathogenic effects depending on the precise state. In this review, we discuss the involvement of extracellular vesicle as mediators of signal transduction in neurodegenerative diseases and cancer. In addition, the role of extracellular vesicles in mediating Wnt and PI3K signaling pathways is also discussed. Additional findings on the involvement of extracellular vesicles in homeostasis and disease progression will promote a better biological understanding, advance future therapeutic and diagnostic applications.

ExoCarta: A Web-Based Compendium of Exosomal Cargo

“…During physiological and pathological conditions, inward budding of late endosomal membranes results in the accumulation of intraluminal vesicles (ILVs) within the multivesicular bodies (MVBs) [3, 4]. Fusion of the MVBs with the plasma membrane results in the release of ILVs into the extracellular microenvironment and from here on referred to as exosomes [5].…”

Placental exosomes in normal and complicated pregnancy

“…1 Exosomes are a subpopulation of extracellular vesicles that are distinct in size (w40-120 nm), density (1.13-1.19 g/mL e1 ), content, and biogenesis. Exosomes are of endosomal origin, formed by the inward budding multivesicular bodies (MVB) (Figure 1).…”

Exosomes in colorectal carcinoma formation: ALIX under the magnifying glass

“…15,16 This process also has an important role in developing tumor chemoresistance and interfering with the tumor microenvironment by modifying stromal cell functions, such as neovascularization, immunosuppression, tumor cell invasion (eg, epithelial to mesenchymal transition) and transition of stromal cells to carcinoma-associated fibroblasts (CAFs). 1,6,17,18 CAFs as key factors of abnormal epithelial-stromal interaction and their powerful tumor-supportive effect (eg, increased regulator ligand and extracellular matrix molecule expression) are well known compared with normal stromal cells with similar morphology, that is, subepithelial myofibroblasts.…”