Prostasomes are neuroendocrine-like vesicles in human semen

Abstract

BACKGROUND Prostasomes are prostate‐derived organelles that exist extracellularly in human seminal plasma. METHODS In this study, we have investigated and characterized human prostasomes with regard to their contents of synaptophysin, members of the chromogranin family, and some neuropeptides. RESULTS By radioimmunoassay measurement and electron microscopy we show the presence of the neuroendocrine markers chromogranin B, neuropeptide Y, and vasoactive intestinal polypeptide in about equimolar amount in human prostasomes and chromogranin A in about 2% of that amount. To our knowledge, such a high ratio of chromogranin B to chromogranin A has never before been observed. The membrane‐bound protein synaptophysin, a well‐established immunocytochemical marker for neuroendocrine cells and neurones, was also detected. Hence, we show that synaptophysin could be used as a marker for intact prestasomes. CONCLUSIONS The presence of synaptophysin has recently been shown in the serotonin‐containing vesicles in platelets. A protein with a similar structure denoted granulophysin has been found in granulocytes and prostasomes. It is suggested that synaptophysin and granulophysin molecules are members of a family of proteins, maybe expressed in all cells that have regulated release of granule content. Our presented data indicate a neurotransmittor function of the prostasomes. The target cells are however not known but could be either the spermatozoa, the epithelial mucous cells of the uterus or tubas or perhaps the ovum. © 1996 Wiley‐Liss, Inc.

Exosomes in Prostate Cancer: Putting Together the Pieces of a Puzzle

“…Stridsberg et al . reported the prostasomes as neuroendocrine-like vesicles, as they contain neuroendocrine markers, chromogranin B, neuropeptide Y, and vasoactive intestinal polypeptide [79]. Prostasomes have a mean diameter of 150 nm, even though some authors report a broader range of 40–500 nm vesicles; they contain CD38, PSMA, and Anx1, have a complex membrane composition (cholesterol/phospholipid ratio 2:1), as well as expressing exosomal markers, CD9 and CD63 [6,80,81,82], and other markers such as CD46, CD55 and CD59 [83,84,85].…”

Differentiation of Human Prostate Cancer PC-3 Cells Induced by Inhibitors of Inosine 5′-Monophosphate Dehydrogenase

“…These organelles contain in their membrane a variety of proteins including complement regulators CD46 (14), CD55, and CD59 (15), an essential cofactor for coagulation, tissue factor (16), and several peptidase activities, including dipeptidyltranspeptidase/CD26 (17), neutral endopeptidase/CD10 (18), aminopeptidase N/CD13 (19), ␥-glutamyltranspeptidase (20), and aminopeptidase P (21). The prostasomes also contain neuroendocrine markers including chromogranin B, neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) (22) and the common secretory granule protein granulophysin/CD63 (23). Although the physiologic function of the prostasomes is still not clearly defined, they display properties that are beneficial to sperm (24 -29).…”

The Male Role in Pregnancy Loss and Embryo Implantation Failure

“…Synaptophysin and chromogranin A were found in about 10 % and 2 %, respectively, of that amount (Stridsberg et al 1996). It was reported that prostasomes express a common secretory granule protein, viz.…”