Addition of follicular fluid to oocyte maturation medium can affect cumulus cell function, increase competence of the oocytes to be fertilised and develop to the blastocyst stage and protect the oocyte from heat shock. Here, it was tested whether exosomes in follicular fluid are responsible for the effects of follicular fluid on the function of the cumulus–oocyte complex (COC). This was accomplished by culturing COCs during oocyte maturation at 38.5°C (body temperature of the cow) or 41°C (heat shock) with follicular fluid or exosomes derived from follicular fluid and evaluating various aspects of function of the oocyte and the embryo derived from it. Negative effects of heat shock on cleavage and blastocyst development, but not cumulus expansion, were reduced by follicular fluid and exosomes. The results support the idea that exosomes in follicular fluid play important roles during oocyte maturation to enhance oocyte function and protect it from stress.

No abstract

Exosomes are nano‐sized vesicles that are involved in various biological processes including cell differentiation, proliferation, signaling, and intercellular communication. Urinary exosomes were isolated from a cohort of hereditary α‐tryptasemia (HαT) patients and from healthy volunteers. There was a greater number of exosomes isolated from the urine in the HαT group compared to the control volunteers. Here, we investigated the differences in both lipid classes and lipid species within urinary exosomes of the two groups. Lipids were extracted from urinary exosomes and subjected to liquid chromatography mass spectrometry using a targeted approach. Various molecular species of glycerophospholipids, glycerolipids, and sterols were significantly reduced in HαT patients. Out of a possible 1127 lipids, 521 lipid species were detected, and relative quantities were calculated. Sixty‐four lipids were significantly reduced in urinary exosomes of HαT patients compared to controls. All significantly reduced sphingolipids and most of the phospholipids were saturated or mono‐unsaturated lipids. These results suggest exosome secretion is augmented in HαT patients and the lipids within these exosomes may be involved in various biological processes. The unique lipid composition of urinary exosomes from HαT patients will contribute to our understanding of the biochemistry of this disease.

Reports of the stimulated release of extracellular vesicles (EVs) are few, and the mechanisms incompletely understood. To our knowledge, the possibility that the activation of any one of the multitudes of G‐protein‐coupled receptors (GPCRs) expressed by a single cell‐type might increase EV release has not been explored. Recently, we identified the expression of cholecystokinin (CCK), gastrin, gastrin/cholecystokinin types A and/or B receptors (CCKAR and/or –BR), and the bitter taste receptor, TAS2R14 in the human and mouse placenta. specifically, trophoblast. These GPCR(s) were also expressed in four different human trophoblast cell lines. The current objective was to employ two of these cell lines—JAR choriocarcinoma cells and HTR‐8/SVneo cells derived from first‐trimester human villous trophoblast—to investigate whether CCK, TAS2R14 agonists, and other GPCR ligands would each augment EV release. EVs were isolated from the cell‐culture medium by filtration and ultracentrifugation. The preparations were enriched in small EVs (<200 nm) as determined by syntenin western blot before and after sucrose gradient purification, phycoerythrin (PE)‐ADAM10 antibody labeling, and electron microscopy. Activation of TAS2R14, CCKBR, cholinergic muscarinic 1 & 3, and angiotensin II receptors, each increased EV release by 4.91‐, 2.79‐, 1.87‐, and 3.11‐fold, respectively (all p < .05 versus vehicle controls), without significantly changing EV diameter. A progressive increase of EV concentration in conditioned medium was observed over 24 hr consistent with the release of preformed EVs and de novo biogenesis. Compared to receptor‐mediated stimulation, EV release by the calcium ionophore, A23187, was less robust (1.63‐fold, p = .08). Diphenhydramine, a TAS2R14 agonist, enhanced EV release in JAR cells at a concentration 10‐fold below that required to increase intracellular calcium. CCK activation of HTR‐8/SVneo cells, which did not raise intracellular calcium, increased EV release by 2.06‐fold (p < .05). Taken together, these results suggested that other signaling pathways may underlie receptor‐stimulated EV release besides, or in addition to, calcium. To our knowledge, the finding that the activation of multiple GPCRs can stimulate EV release from a single cell‐type is unprecedented and engenders a novel thesis that each receptor may orchestrate intercellular communication through the release of EVs containing a subset of unique cargo, thus mobilizing a specific integrated physiological response by a network of neighboring and distant cells.