Database Commons

a catalog of worldwide biological databases

Exosomes are a class of extracellular vesicles that are secreted by various cell types. Unlike other extracellular vesicles (ectosomes and apoptotic blebs), exosomes are of endocytic origin. The roles of exosomes in vaccine/drug delivery, intercellular communication and as a possible source of disease biomarkers have sparked immense interest in them, resulting in a plethora of studies. Whilst multidimensional datasets are continuously generated, it is difficult to harness the true potential of the data until they are compiled and made accessible to the biomedical researchers. Here, we describe ExoCarta (http://www.exocarta.org), a manually curated database of exosomal proteins, RNA and lipids. Datasets currently present in ExoCarta are integrated from both published and unpublished exosomal studies. Since its launch in 2009, ExoCarta has been accessed by more than 16,000 unique users. In this article, we discuss the utility of ExoCarta for exosomal research and urge biomedical researchers in the field to deposit their datasets directly to ExoCarta.

Exosomes, membrane microvesicles (40-100 nm) secreted by most cell types, can be isolated in several ways while characterizing them is heavily based on electron microscopy and, most importantly, the identification of exosome marker proteins. Researchers rely on the identification of certain exosomal marker proteins including Alix, CD9 and CD63 to confirm the presence of exosomes in their preparations. An evolutionary-conserved set of protein molecules have been identified in most exosomes studied to date. However, with the complexity of tissue/cell type-specific proteins being incorporated in the exosomes, some of these so-called exosomal markers are not always present in all the exosomes. The presence of tissue/cell type-specific proteins in exosomes allows researchers to isolate them using immunoaffinity capture methods. A compendium for exosomal proteomes will aid researchers in identifying proteins that were more commonly found in various exosomes (exosome markers) and those that are specific to certain tissue/cell type-derived exosomes. Here, we describe ExoCarta, a compendium for proteins and RNA molecules identified in exosomes. ExoCarta is first of its kind and the resource is freely available to the scientific community through the web (http://exocarta.ludwig.edu.au). We believe that this community resource will be of great biological importance for any future exosome analyses.