Microvesicles may represent a new tool of intercellular communication. Two different microvesicle types have been identified: membrane-derived vesicles (abbreviated EVs) and exosomes. The former is originated by direct budding from the plasma membrane, while the latter origins from ectocytosis of multivesicular bodies. Recently, a particular attention has been focused on the capacity of EVs to alter the phenotype of neighboring cells towards the phenotype of EV producing cells. It has been observed that stem cells are an abundant source of EVs. The interaction of stem cells with the microenvironment (i.e. stem cell niche) has a critical role in determining stem cell phenotype. The stem cell niche hypothesis predicts that stem cell number can be limited by the availability of niches that release the necessary signals for self-renewal and survival. Consequently, the niche provides a mechanism to control and limit stem cell number. In this context, EVs may have a fundamental role by transfer genetic information between cells. In fact, they are able to transfer to target cells both mRNA and miRNA, which may be involved in phenotypic changes of target cells toward the phenotype of EV producing cells. The exchange of genetic information may be bidirectional. In fact, after tissue damage, EV-mediated transfer of genetic information may reprogram the phenotype of stem cells to acquire features of the injured tissue cells. In addition, stem cell derived EVs may induce de-differentiation of cells which have surveyed injury with a re-entry in cell cycle and the possibility of tissue regeneration.
Extracellular membrane vesicles as mechanism of cell-to-cell communication
Turturici G, Tinnirello R, Sconzo G, Geraci F. (2014) Extracellular membrane vesicles as mechanism of cell-to-cell communication: advantages and disadvantages. Am J Physiol Cell Physiol [Epub ahead of print]. [abstract]