title: Polysialic acid is present in mammalian semen as a post-translational modification of the neural cell adhesion molecule NCAM and the polysialyltransferase ST8SiaII.
abstract: Fertilization in animals is a complex sequence of several biochemical events beginning with the insemination into the female reproductive tract and, finally, leading to embryogenesis. Studies by Kitajima and co-workers (Miyata, S., Sato, C., and Kitajima, K. (2007) Trends Glycosci. Glyc, 19, 85-98) demonstrated the presence of polysialic acid (polySia) on sea urchin sperm. Based on these results, we became interested in the potential involvement of sialic acid polymers in mammalian fertilization. Therefore, we isolated human sperm and performed analyses, including Western blotting and mild 1,2-diamino-4,5-methylenedioxybenzene-HPLC, that revealed the presence α2,8-linked polySia chains. Further analysis by a glyco-proteomics approach led to the identification of two polySia carriers. Interestingly, besides the neural cell adhesion molecule, the polysialyltransferase ST8SiaII has also been found to be a target for polysialylation. Further analysis of testis and epididymis tissue sections demonstrated that only epithelial cells of the caput were polySia-positive. During the epididymal transit, polySia carriers were partially integrated into the sperm membrane of the postacrosomal region. Because polySia is known to counteract histone as well as neutrophil extracellular trap-mediated cytotoxicity against host cells, which plays a role after insemination, we propose that polySia in semen represents a cytoprotective element to increase the number of vital sperm.
authors.affiliation: Institute of Biochemistry, Faculty of Medicine, Justus-Liebig-University, 35392 Giessen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Simon
authors.forename: Sören
authors.initials: S
authors.lastname: Bäumner
authors.forename: Oliver
authors.initials: O
authors.lastname: Busch
authors.forename: René
authors.initials: R
authors.lastname: Röhrich
authors.forename: Miriam
authors.initials: M
authors.lastname: Kaese
authors.forename: Peter
authors.initials: P
authors.lastname: Richterich
authors.forename: Axel
authors.initials: A
authors.lastname: Wehrend
authors.forename: Karin
authors.initials: K
authors.lastname: Müller
authors.forename: Rita
authors.initials: R
authors.lastname: Gerardy-Schahn
authors.forename: Martina
authors.initials: M
authors.lastname: Mühlenhoff
authors.forename: Hildegard
authors.initials: H
authors.lastname: Geyer
authors.forename: Rudolf
authors.initials: R
authors.lastname: Geyer
authors.forename: Ralf
authors.initials: R
authors.lastname: Middendorff
authors.forename: Sebastian P
authors.initials: SP
authors.lastname: Galuska
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004822:Epididymis / Q000378:metabolism; D005260:Female; D005306:Fertilization; D006801:Humans; D008297:Male; D051379:Mice; D008856:Microscopy, Fluorescence; D019006:Neural Cell Adhesion Molecules / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D040901:Proteomics / Q000379:methods; D051381:Rats; D012661:Semen / Q000378:metabolism*; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism
chemical_list: D019006:Neural Cell Adhesion Molecules; D012794:Sialic Acids; C021319:polysialic acid; C046778:CMP-N-acetylneuraminate-poly-alpha-2,8-sialosyl sialyltransferase; D012799:Sialyltransferases
keywords: Cell Adhesion; Fertilization; Mammalian Sperm; NCAM; Polysaccharide; Polysialic Acid; Polysialyltransferase; Post-translational Modification; ST8SiaII; Spermatozoa