Enhancement of human sperm motility by trophinin binding peptide
ABSTRACT Previously we found that the trophinin-binding peptide GWRQ (glycine, tryptophane, arginine, glutamic acid) activated human trophoblastic cells. Although trophinin is expressed in human sperm, to our knowledge the function of this protein is not known. In this study we tested the effect of GWRQ on human sperm to evaluate whether the peptide enhances human sperm motility.
Immunohistochemistry was performed using monoclonal antibodies specific to trophinin, bystin or tastin. GWRQ-MAPS (multivalent 8-branched GWRQ peptide) was chemically synthesized. Human sperm from 4 volunteers with a mean +/- SD age of 35.75 +/- 3.4 years was suspended in buffer with GWRQ or control peptides. In 23 volunteers with a mean age of 25.5 +/- 2.5 years the number of immotile sperm was counted and subtracted from the total number of sperm to determine the number of motile sperm. A Transwell assay was used to measure swim-down motility. Levels of adenosine triphosphate and intracellular calcium in sperm cells incubated with GWRQ or control peptide were measured using a luminescent cell viability assay and a fluo-4 calcium assay, respectively.
The presence of trophinin and the trophinin associated proteins bystin and tastin in human sperm was confirmed by immunohistochemistry. Human sperm incubated with GWRQ-MAPS showed enhanced motility on sperm count assay and swim-down Transwell assay. Sperm cells incubated with GWRQ-MAPS showed decreased adenosine triphosphate and increased intracellular calcium.
Results suggest that GWRQ-MAPS may facilitate optimized in vitro fertilization outcomes and help avert the need for intracytoplasmic sperm injection in cases of severely low sperm motility. Trophinin may have a role in regulating adenosine triphosphatase in human sperm.
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ABSTRACT: Fibroblast growth factors (FGFs) and their receptors are expressed in a variety of mammalian tissues, playing a role in development and cell proliferation. While analyzing human sperm motility, we found that sperm treated with endo-β-galactosidase (EBG), which specifically hydrolyzes poly-N-acetyllactosamine type glycans (polyLacs), enhanced motility. Mass spectrometry analysis revealed that sperm-associated polyLacs are heavily fucosylated, consistent with Lewis Y antigen. Immunohistochemistry of epididymis using an anti-Lewis Y antibody before and after EBG treatment suggested that polyLacs carrying the Lewis Y epitope are synthesized in epididymal epithelia and secreted to seminal fluid. EBG-treated sperm elevated cAMP levels and calcium influx, indicating activation of fibroblast growth factor signaling. Seminal fluid polyLacs bound to FGFs in vitro, and impaired FGF-mediated signaling in HEK293T cells.FEBS letters 08/2013; 587(19). DOI:10.1016/j.febslet.2013.07.056 · 3.34 Impact Factor
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ABSTRACT: Trophinin is an intrinsic membrane protein expressed in trophectoderm cells of embryos and in uterine epithelial cells. Trophinin potentially mediates apical cell adhesion at human embryo implantation sites through trophinin-trophinin binding in these two cell types. Trophinin-mediated cell adhesion activates trophectoderm cells for invasion, whereas the effect of adhesion on maternal side is not known. We show that addition of GWRQ peptide, a previously established peptide that mimics trophinin-mediated cell adhesion, to human endometrial epithelial cells expressing trophinin induces their apoptosis. FAS involvement was excluded, as GWRQ did not bind to FAS, and FAS knockdown did not alter GWRQ-induced apoptosis. Immunoblotting analyses of protein kinases revealed an elevation of PKC-d protein in GWRQ-bound endometrial epithelial cells. In the absence of GWRQ, PKC-d associated with trophinin and remained cytoplasmic, but after GWRQ binding to the trophinin extracellular domain, PKC-d became tyrosine phosphorylated, dissociated from trophinin, and entered the nucleus. In PKC-d knockdown endometrial cells, GWRQ did not induce apoptosis.Cell cycle (Georgetown, Tex.) 01/2011; 10(1):135-43. DOI:10.4161/cc.10.1.14448 · 5.01 Impact Factor
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ABSTRACT: For fertilization to occur in mammals, ejaculated spermatozoa must reach the egg which, following ovulation has moved from the ovary into the Fallopian tube. Two active mechanisms of spermatozoa guidance have been shown in mammals: thermotaxis and chemotaxis. The identity of most of human spermatozoa chemoattractants is unknown, and herein we tested if SDF1 (chemokine stromal cell-derived factor-1) and its pathway is involved in spermatozoa chemotaxis. We found that SDF1 is expressed in the oocytes, endometrium and follicular fluid, as well as its specific receptor CXCR4 (chemokine CXC motif receptor 4) is expressed in the head of spermatozoa. By SDF1 gradient experiments, we stated that SDF1 is able to induce hyperactivation in spermatozoa leading to accumulation, to give rise to an increase in intracellular calcium concentration, and to preserve the mitochondrial status and not to induce acrosome reaction. Our findings suggest these phenomena could reflect spermatozoa chemotaxis, and that SDF1 action could represent an important event leading to egg fertilization, even if further studies regarding the link between spermatozoa accumulation and chemotaxis are mandatory. These data suggest that the SDF-1/CXCR4 signalling could be used to manipulate the human fertilization, to improve both the outcome of physiological or assisted reproduction, and to develop new contraceptive methods, by development of SDF1 or CXCR4 antagonist.International Journal of Andrology 05/2011; 34(6 Pt 2):e554-65. DOI:10.1111/j.1365-2605.2011.01158.x · 3.21 Impact Factor