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 µm 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.