Prostasomes Are Heterogeneous Regarding Size and Appearance but Affiliated to one DNA-Containing Exosome Family

BACKGROUND. Prostate acinar epithelial cells release microvesicles (prostasomes) that possess pleiotropic biological effects relevant for successful fertilization. Prostasomes are formed in a similar way as exosomes but are heterogeneous as regards size and appearance. Like exosomes they are thought to be mediators of intercellular communication. METHODS. We prepared seminal prostasomes in accordance with the prevailing protocol for exosome preparation including passage through a 0.2 mu m filter and centrifugation in a sucrose gradient. RESULTS. We compared the filterable prostasomes with those trapped on the filter (nonfilterable prostasomes) and, qualitatively, no conspicuous differences were apparent regarding ultrastructure and SDS-PAGE banding pattern. Moreover, both types of prostasomes contained DNA fragments and Western blot revealed presence of prostate specific membrane antigen (PSMA), CD38, and annexin A1. CONCLUSIONS. Reasonably, prostasomes could be included in the exosome family and be regarded as one entity containing chromosomal DNA. Prostate 72: 1736-1745, 2012. (C) 2012 Wiley Periodicals, Inc.