Anti-GAPDHS antibodies can inhibit in vitro sperm-oocyte binding

0445179 - BTÚ 2016 US eng A - Abstract
Dorosh, Andriy - Margaryan, Hasmik - Čapková, Jana - Maňásková-Postlerová, Pavla - Pěknicová, Jana
Anti-GAPDHS antibodies can inhibit in vitro sperm-oocyte binding.
Abstract Book - SSR 2015 Annual Meeting. Madison: Society for the Study of Reproduction, 2015. s. 212.
[48th Annual Meeting of the Society for the Study of reproduction. 18.06.2015-22.06.2015, San Juan]
R&D Projects: GA ČR(CZ) GAP503/12/1834; GA MŠMT(CZ) ED1.1.00/02.0109
Institutional research plan: CEZ:AV0Z50520701
Institutional support: RVO:86652036
Keywords : GAPDHS * antibodies * sperm-oocyte binding * acrosin * zona pellucida
Subject RIV: CE - Biochemistry

There are ten enzymes of the glycolytic pathway which are highly conserved and present in nearly all organisms. In male germ cells undergoing spermatogenesis, at least some somatic glycolytic enzymes are replaced with sperm-specific isoforms. Glyceraldehyde 3-phosphate dehydrogenase-spermatogenic (GAPDHS) is encoded with different gene than somatic GAPDH and was shown to be essential for energy production and sperm motility. We hypothesized that GAPDHS, like its somatic counterpart, might be involved in other cellular processes in addition to glycolysis. In this study, we first characterized the sperm protein recognized by a monoclonal antibody Hs-8. In the immunofluorescence test, Hs-8 antibody recognized the protein localized in the acrosomal part of the sperm head and in the principal piece of the sperm flagellum in the human, boar and mouse spermatozoa. Hs-8 labeled the 45 kDa protein in the extract of human sperm and with sequence analysis it was identified as GAPDHS. Next, functional analysis of the GAPDHS from the sperm acrosome was performed using the boar sperm/zona pellucida binding assay. We tested the effect of both Hs-8 and anti-GAPDHS antibodies, while anti-P4 (anti-progesterone) and ACR.2 (anti-acrosin) were used as negative and positive controls, respectively. There was a four- to five-fold decrease in the number of bound sperm cells to the oocyte, when ACR.2, Hs-8, or anti-GAPDHS antibodies were present in the incubation medium. Anti-P4 had no effect on the sperm/oocyte binding. The outcome of the in vitro sperm/oocyte binding assay suggests involvement of the GAPDHS protein in the secondary sperm/zona pellucida binding. To sum up, we confirmed GAPDHS localization in the apical part of the sperm head in addition to the principal piece of the flagellum. In an indirect binding assay, we showed that anti-GAPDHS antibodies interfere with the secondary sperm/oocyte binding.
Permanent Link: http://hdl.handle.net/11104/0248855