title: Role of cholesterol, DOTAP, and DPPC in prostasome/spermatozoa interaction and fusion.
abstract: Prostasomes are membranous vesicles present in ejaculated human semen. They are very rich in cholesterol and can interact with spermatozoa. Their physiological roles are still under study. Prostasomes were mixed with liposomes prepared from various lipids, such as N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium (DOTAP), DOTAP/1,2-dipalmytoyl-sn-glycero-3-phosphorylcholine (DPPC, 4:1 molar ratio) and DOTAP/cholesterol (4:1, molar ratio) at different pH values (5-8). The mixing of the lipid phases (fusion) was determined by the relief of octadecyl rhodamine B chloride (R(18)) self-quenching and the radii of the vesicles, by light scattering measurements. The mixing of lipids and the radii of prostasomes were both influenced by the addition of liposome, although in a different manner. The ability of prostasomes (modified by previous treatment with liposomes) to transfer lipid to spermatozoa was also measured. Pretreatment with DOTAP decreased the phenomenon and addition of DPPC abolished it. On the other hand, pretreatment of prostasomes with DOTAP/cholesterol liposomes did not affect the transfer of lipid between prostasome and spermatozoa. Therefore, the ability of vesicles to fuse (or, at least, to exchange the lipid component) was affected by the enrichment in either natural or artificial lipid. This may open new possibilities for the modulation of spermatozoa capacitation and acrosome reaction.
authors.affiliation: Department of Internal Medicine, Laboratory of Biochemistry, University of Perugia, Via del Giochetto, I-06122 Perugia, Italy.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Palmerini
authors.forename: Cesare
authors.initials: C
authors.lastname: Cametti
authors.forename: Simona
authors.initials: S
authors.lastname: Sennato
authors.forename: Diego
authors.initials: D
authors.lastname: Gaudino
authors.forename: Enrico
authors.initials: E
authors.lastname: Carlini
authors.forename: Federico
authors.initials: F
authors.lastname: Bordi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arienti
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000494:pharmacology*; D000328:Adult; D002450:Cell Communication / Q000187:drug effects*; D002459:Cell Fusion; D002784:Cholesterol / Q000494:pharmacology*; D005229:Fatty Acids, Monounsaturated / Q000494:pharmacology*; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008297:Male; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D012661:Semen / Q000737:chemistry / Q000187:drug effects* / Q000378:metabolism; D013094:Spermatozoa / Q000166:cytology / Q000187:drug effects*
chemical_list: D005229:Fatty Acids, Monounsaturated; D008055:Lipids; D008081:Liposomes; D000644:Quaternary Ammonium Compounds; D015060:1,2-Dipalmitoylphosphatidylcholine; D002784:Cholesterol; C070046:1,2-dioleoyloxy-3-(trimethylammonium)propane