Apoptotic Bodies: Particular Extracellular Vesicles Involved in Intercellular Communication

Abstract

In the last decade, a new method of cell-cell communication mediated by membranous extracellular vesicles (EVs) has emerged. EVs, including exosomes, microvesicles, and apoptotic bodies (ApoBDs), represent a new and important topic, because they are a means of communication between cells and they can also be involved in removing cellular contents. EVs are characterized by differences in size, origin, and content and different types have different functions. They appear as membranous sacs released by a variety of cells, in different physiological and patho-physiological conditions. Intringuingly, exosomes and microvesicles are a potent source of genetic information carriers between different cell types both within a species and even across a species barrier. New, and therefore still relatively poorly known vesicles are apoptotic bodies, on which numerous in-depth studies are needed in order to understand their role and possible function. In this review we would like to analyze their morpho-functional characteristics.

Keywords: apoptotic bodies; extracellular vesicles; intercellular communication; ultrastructure.

Figure 1

Scheme of extracellular vesicle formation. In this figure shows the biogenesis and release of microvesicles and exosomes. Their morphology was observed by transmission electron microscope (TEM) after negative staining. Apoptotic body extrusion appears in the scheme and in sections of conventionally embedded apoptotic cells. m = mitochondria, rer = rough endoplasmic reticulum, mic = micronuclei, Bar = 200 nm.

Figure 2

Schematic representation of nuclear changes during early apoptotic phases. Chromatin condensation (cc) and nuclear pore translocation (np) are also seen in TEM observations. dc = diffuse chromatin. Bar = 600 nm.

Figure 3

TEM of apoptotic bodies. Bar = 600 nm.