Role of intracellular Ca2+ on the formation of microvesicle in human red blood cells

Abstract

Release of vesicles from various cell types has been seen as a kind of intercellular communication. So far three types of vesicles have been described including exosomes (40-100 nm), microvesicles (100-1,000 nm) and apoptotic bodies (1-4 mm). Although the mechanisms for the formation of vesicles are unclear at the moment, microvesicles (MVs) have been reported as a mean of transport for lipids, growth factors, protein, RNA and signal molecules among cells. In human, red blood cells (RBCs) are the most common type of blood cell which deliver oxygen to the body tissues. The formation and release of MVs from RBCs have been reported for years. However, the mechanism for the formation and function of MVs released from RBCs has not well understood. In this study, conditions for the formation and release of MVs from human (RBCs) have been investigated. By using fluorescence label techniques, fluorescence microscope and flow cytometer. The results showed that phorbol-12-myristat-13-acetate (PMA), lysophosphatidic acid (LPA) and calcium inonophore (A23187) induced the increase of intracellular Ca2+. Increase of intracellular of Ca2+ led to the formation, shedding and release of MVs in human RBCs. The formation of MVs was also coupled with the externalization of phosphatidyl serine (PS). The kinetics of the formation of MVs was investigated by using annexin V-FITC. The obtained results showed that increase intracellular Ca2+ led to cell shrinkage, formation and release of MVs in human RBCs.