On the right, a representative image of individual sperm is depicted; (A) sperm stained with anti FGFR antibody and Cy3-conjugated secondary antibody, (B) FITC-PSA, (C) merge. Activation of sperm FGFRs and FGFR-related intracellular pathways To analyze the activation of sperm FGFRs, cells were exposed to FGF2 and FGFR phosphorylation Cerpegin was evaluated by immunocytochemistry. GUID:?BB4C44CB-ECBD-4823-9C9B-81B10710D561 Data Availability StatementAll relevant data are within the paper and its Supporting Information files. Abstract Fibroblast growth factors receptors (FGFRs) have been widely characterized in somatic cells, but there is scarce evidence of their expression and function in mammalian gametes. The objective of the present study was to evaluate the expression of FGFRs in human Cerpegin male germ cells, to determine sperm FGFR activation by the FGF2 ligand and their participation in the regulation Cerpegin of sperm motility. The expression of FGFR1, 2, 3 and 4 mRNAs and proteins in human testis and localization of these receptors in germ cells of the seminiferous epithelium was demonstrated. In ejaculated sperm, FGFRs were localized to the acrosomal region and flagellum. Sperm exposure to FGF2 caused an increase in flagellar FGFR phosphorylation and activation of extracellular signal-regulated kinase (ERK) and protein kinase B (PKB or Akt) signaling pathways. Incubation with FGF2 led to a significant increase in the percentage of total and progressive sperm motility, as well as in sperm kinematics. All responses were prevented by Mouse monoclonal to RFP Tag sperm preincubation with BGJ398, a specific inhibitor of FGFR tyrosine kinase activity. In addition to confirming the expression of FGFRs in germ cells of the human testis, our study describes for the first time the presence, localization and functionality of human sperm FGFRs, and provides evidence of the beneficial effect of FGF2 upon sperm motility. Introduction Fibroblast growth factors (FGFs) constitute a family of 17C34 kDa proteins, being FGF2 the best-characterized member of this family [1, 2]. FGFs bind to specific receptors (FGFRs) composed of 3 extracellular immunoglobulin-like domains, a single transmembrane domain, and 2 highly conserved cytoplasmic domains with tyrosine kinase activity. Among FGFRs, the most studied are FGFR1, FGFR2, FGFR3 and FGFR4 [3, 4]. Transcripts coding the extracellular domains of FGFR1, FGFR2 and FGFR3 are subjected to alternative splicing, giving rise to 2 or 3 3 receptor isoforms (IIIa, IIIb and IIIc) with specific tissue expression and different ligand binding properties . In particular, FGF2 has been shown to bind with high affinity to FGFR1 IIIb and IIIc, FGFR2 IIIc, FGFR3 IIIc and FGFR4, but not to other FGFR isoforms . Interaction of FGFs with heparin or heparan sulfate proteoglycans allows their binding to FGFRs, triggering receptor dimerization and phosphorylation . Activation of FGFRs leads to the activation of the Ras/mitogen activated protein kinase (MAPK) or extracellular signal-regulated kinase (ERK) pathway as well as the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB or Akt) signaling pathway. In somatic cells, components of these signal transduction cascades translocate to the nucleus and phosphorylate specific transcription factors, inducing the expression of FGF-target genes . FGF and FGFR expression has been reported in multiple tissues [9, 10] and both, ligands and receptors, have been implicated in cell proliferation, differentiation, adhesion, survival, apoptosis, and motility. This system has been related to normal tissue maintenance, repair and regulation as well as to tumor progression [11, 12]. In the female reproductive tract, FGFs and FGFRs Cerpegin have been involved in folliculogenesis, embryo implantation and development [13, 14]. Components of the FGF/FGFR pathway have also been found in tissues of the male reproductive tract from several species [6, 15, 16]. Transgenic mice expressing a dominant-negative variant of FGFR1 in the male haploid germ cells are subfertile, show diminished daily sperm output and reduced ability to undergo cellular changes associated with sperm capacitation , suggesting that this system has a relevant role in spermatogenesis/spermiogenesis and in the regulation of sperm physiology. Contrasting, a recent study reported that germ cell-specific FGFR1 or FGFR2 mutant mice have normal fertility and spermatogenesis, because of compensatory systems exerted by various other FGFRs  possibly. However, before present time a Cerpegin couple of zero reviews over the FGFR function and expression in the human sperm. The purpose of the present research was.