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Query: UNIPROT:P56851 (epididymal)
 11,273 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fertilization involves adhesive interactions between gametes similar to those mediated by fibronectin (FN) in other cellular systems. Fibronectin has been found on the equatorial segment of ejaculated human serum. As sperm capacity to interact with the oocyte is acquired during epididymal transit, the possible participation of FN in human sperm maturation was studied. The presence of FN in both epididymal sperm and fluid was demonstrated by the detection of a major component of 220 kD in immunoblot studies using anti-FN antisera. The concentration of FN in soluble tissue extracts of epididymis was determined by enzyme-linked immunosorbent assay (ELISA). A gradual increase along the length of the organ, averaging 12-fold from proximal caput to distal corpus, was detected. Immunocytochemistry assays indicated that the number of spermatozoa with immunoreactive FN over the equatorial segment increased from 18% in caput to 64% in distal corpus epididymis. Immunoprecipitation of medium from epididymal explants culture with anti-FN antiserum demonstrated the de novo synthesis of FN in vitro. The greater number of FN-positive sperm coincident with FN accumulation in distal regions of the epididymis supports the role of FN in sperm maturation.
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PMID:Characterization of fibronectin as a marker for human epididymal sperm maturation. 147 75

Transforming growth factor-beta 1 (TGF-beta 1) is angiogenic in vivo. In two-dimensional (2-D) culture systems microvascular endothelial cell proliferation is inhibited up to 80% by TGF-beta 1; however, in three-dimensional (3-D) collagen gels TGF-beta 1 is found to have no effect on proliferation while eliciting the formation of calcium and magnesium dependent tube-like structures mimicking angiogenesis. DNA analyses performed on 3-D cell cultures reveal no significant difference in the amount of DNA or cell number in control versus TGF-beta 1 treated cultures. In 2-D cultures TGF-beta 1 is known to increase cellular fibronectin accumulation; however, in 3-D cultures no difference is seen between control and TGF-beta 1 treated cells as established by ELISA testing for type IV collagen, fibronectin, and laminin. In 3-D cultures there is increased synthesis and secretion of type V collagen in both control and TGF-beta 1 treated cultures over 2-D cultures. Even though an equal amount of type V collagen is seen in both 3-D conditions, there is a reorganization of the protein with concentration along an organizing basal lamina in TGF-beta 1 treated cultures. EM morphological analyses on 3-D cultures illustrate quiescent, control cells lacking cell contacts. In contrast, TGF-beta 1 treated cells show increased pseudopod formation, cell-cell contact, and organized basal lamina-like material closely apposed to the "abluminal" plasma membranes. TGF-beta 1 treated cells also appear to form junctional complexes between adjoining cells. Immunofluorescence using specific antibodies to the tight junction protein ZO-1 results in staining at apparent cell-cell junctions in the 3-D cultures. Northern blots of freshly isolated microvascular endothelium, 2-D and 3-D cultures, using cDNA and cRNA probes specific for the ZO-1 tight junction protein, reveal the presence of the 7.8 kb mRNA. Western blots of rat epididymal fat pad endothelial cells (RFC) monolayer lysates probed with anti-ZO-1 label a 220 kd band which co-migrates with the bonafide ZO-1 protein. These data confirm and support the hypothesis that TGF-beta 1 is angiogenic in vitro, eliciting microvascular endothelial cells to form tube-like structures with apparent tight junctions and abluminal basal lamina deposition in three-dimensional cultures.
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PMID:Transforming growth factor beta 1 modulates extracellular matrix organization and cell-cell junctional complex formation during in vitro angiogenesis. 168 59

The ability of mouse epididymal and human ejaculated spermatozoa to bind to beads coated with various extracellular matrix components was examined. Mouse spermatozoa preferentially bound to beads coated with heparin (average values ranging between 6.2 and 8.8 sperm per bead were obtained in different experiments) and with chondroitinsulfate (6.2-7.0), and also, although with significant differences across replicate experiments, to beads coated with laminin (7.9-15.6 sperm per bead) and with collagen type I (6.1-18.5). Human spermatozoa bound to collagen-coated beads (15.4-22.6 sperm per bead) and, to a much lower extent, to chondroitin-sulfate-coated beads (3.2-4.7); they were also able to bind heparin-coated beads, although with ample differences between individual sperm donors (ranging between 0.8 and 18.7 sperm per bead). Very few human and mouse sperm bound fibronectin-coated beads; beads coated with albumin, hyaluronic acid, and chondronectin were always totally free of adhering sperm. The possible physiological role of the interactions between spermatozoa and extracellular matrix components are discussed.
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PMID:Selective binding of mouse and human spermatozoa to beads coated with extracellular matrix components. 212 12

The effect of recombinant human tumor necrosis factor (TNF) on the capillary growth was evaluated using an in vitro angiogenesis model recently developed. Sprague-Dawley rat microvessel fragments, from epididymal fat pads, seeded onto the confluent culture of myofibroblastic cells from the same tissue origin, gave rise to microvascular networks on and in the multilayered myofibroblastic cells. In contrast, the capillary growth from the vessel fragments was markedly inhibited in the presence of 10-1,000 U TNF/ml. Monoclonal antibody against TNF completely neutralized the capillary growth inhibitory activity of TNF. The mode of angiogenesis inhibitory action of TNF was also examined by use of bovine capillary endothelial (BCE) cells and rat myofibroblastic cells. TNF exerted growth inhibitory and cytotoxic actions against BCE cells cultivated on the various basement membrane components, such as extracellular matrix secreted by BCE cells, fibronectin, laminin, and type IV collagen. An irreversible damage to most of the BCE cells was observed ultrastructurally after 60 hours' exposure to TNF. TNF, however, did not injure the myofibroblastic cells but rather stimulated their growth. These findings indicate that TNF inhibits in vitro capillary growth by its direct cytostatic and cytotoxic actions to microvascular endothelial cells.
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PMID:Tumor necrosis factor inhibiting angiogenesis in vitro. 244 19

Spermatozoa were prepared by swim up technique in the same way as for in vitro fertilization of human eggs and incubated with antihuman fibronectin antibodies in the immunofluorescence technique. Fibronectin mediates adhesive interactions between cells. 69 p.c. of spermatozoa with a normal shape and only 17 p.c. of them exhibiting a pathological shape showed a positive fibronectin-fluorescent band on the equatorial segment, called equatorial fibronectin band (EFB). The cryopreservation of semen did not influence the EFB. The significance of EFB for the sperm-oocyte-binding is discussed in connection with the sperm morphology and epididymal function.
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PMID:The equatorial fibronectin band (EFB) on human spermatozoa--a diagnostic help for male fertility? 331 Jul 35

The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5-6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the "A" cell granules of the endocrine pancreas and gut mucosa cells.
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PMID:Ultrastructural and immunohistochemical studies of rat epididymis. 635 63

A rabbit antibody to mouse 3T3 cell fibronectin was used in conjunction with a fluorescein-tagged second antibody to detect fibronectin-like activity on the surface of rabbit spermatozoa. Only ejaculated sperm displayed an intense and highly localized fluorescence over the acrosomal region. Cauda epididymal sperm of the rabbit as well as several other species did not exhibit any reaction. The fluorescent activity could be eliminated by trypsin treatment but was re-established by incubation in cell-free seminal fluid. Sperm recovered from females 10-12 h after mating showed a reduction or absence of antifibronectin fluorescence, suggesting that this component's loss could be a factor in sperm capacitation. Because fibronectins show strong binding to collagen, mixtures of ejaculated sperm and collagen were examined in the light and electron microscope. Living sperm appear to have a strong affinity for collagen and quickly adhere to the filaments by their heads, while continuing vigorous flagellations. Surface labeling of sperm with the galactose-oxidase-NaB[3H]4 technique, extraction with urea-detergent mixtures and affinity chromatography of extracts on gelatin-Sepharose revealed a single radioactive band of mot wt approximately 40,000 after SDS polyacrylamide gel electrophoresis and fluorography.
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PMID:A collagen-binding protein on the surface of ejaculated rabbit spermatozoa. 699 66

Spermatozoa alter their antigenity and develop the ability of binding to zona pellucida and to vitellus during the epididymal transit. The involvement of spermatozoal adhesion molecules (AM), especially beta 1-integrins in this binding process between the gametes is very likely. Therefore, the influence of epididymis on the binding capacity of AM was indirectly investigated by comparison of AM on ejaculated and on testicular human spermatozoa and spermatogenic cells, respectively. The AM-expression was detected on ejaculated spermatozoa by flow cytometry (EPICS PROFILE II, Coulter Corp., Krefeld, Germany) and on spermatogenic cells by immunohistology using monoclonal antibodies against. beta 1-integrins and matrix proteins. The alpha-chains 3, 5, 6 of the beta 1-integrins and fibronectin were found on ejaculated spermatozoa as well as on spermatogenic cells except spermatogonia. The alpha-4-chain and laminin could only be detected after the epididymal transit of spermatozoa, whereas, the beta-chain of beta 1-integrins was missing on the ejaculated spermatozoa. These findings suggest that AM are predominantly expressed on spermatogenic cells before the epididymal transit but an epididymis-mediated modulation of AM, i.e. masking, demasking or activating of cryptodeterminants is possible. On this way dysfunction of epididymis could be followed by an impairment of AM-mediated binding capacity of spermatozoa.
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PMID:Influence of the epididymis on integrins and matrix proteins of human spermatozoa. 754 21

Heparin-binding proteins (designated BHB-2-BHB-9) were isolated from boar seminal plasma by affinity chromatography on heparin immobilized on polyacrylamide gel, followed by reverse phase HPLC. According to their N-terminal amino acid sequences, BHB-3-BHB-5 belong to the AQN family of spermadhesins and BHB-7-BHB-9 to the AWN family. BHB-6 is composed of two different proteins. The dominant protein (14 kDa) has the N-terminal amino acid sequence HNKQEGRDHD that is identical to the sequence of human semenogelin at positions 85-94. The minor proteins (16 and 17 kDa) belong to the AWN family of spermadhesins. The 14 kDa HNK protein does not crossreact with antibodies against AQN or AWN spermadhesins. BHB-2 also binds to the acrosome of boar epididymal spermatozoa but has the N-terminal sequence DQH. Therefore, basic protein BHB-2 belongs to a new family of DQH sperm surface proteins that are homologous to the acidic proteins from bull and stallion seminal plasma, to the collagen binding domain II in fibronectin and to the leucocyte cell-cell adhesion regulator, but are not homologous to AQN or AWN spermadhesins. Nevertheless, anti-AQN-1 spermadhesin antibodies crossreact strongly with DQH protein. All boar heparin-binding proteins bind concanavalin A indicating their glycoprotein nature, which was proved by the detection of glucosamine and galactosamine residues in their molecules. Furthermore, spermadhesins interact with zona pellucida, protease inhibitors and a polyacrylamide derivative of heparin. Affinity chromatography experiments showed that the DQH protein bound to gelatin-agarose together with the AWN proteins and that the DQH protein and AQN-1 spermadhesin belong to the phosphoryl choline binding proteins.
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PMID:Spermadhesins of the AQN and AWN families, DQH sperm surface protein and HNK protein in the heparin-binding fraction of boar seminal plasma. 987 52

Novel fibronectin type II (Fn2)-module proteins were cloned from human and canine epididymal cDNA libraries. cDNA sequences predicted a highly conserved protein family, related but not homologous to ungulate seminal plasma proteins (approximately 50% sequence identity), and the first known examples of proteins with four tandemly arranged Fn2-domains. By Northern blot and in situ hybridization analyses the encoding mRNAs were shown to be abundant products of the epididymal duct epithelium, but not detectable in other tissues. Homologous mRNAs were identified in the epididymides of various mammals, representing members of this novel protein family of epididymal origin. Within the Fn2-module-encoding stretches, species homologues displayed >85% sequence identity, but showed high variability at their predicted N-termini. An antipeptide antiserum in Western blot analyses detected 30-35 kDa immunoreactive protein bands in epididymal tissue, cauda epididymidal fluid, and sperm membrane protein preparations. The tandem arrangement of increasing numbers of Fn2-modules might functionally correspond to the tendency to form oligomers that has been described for lipid-binding proteins.
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PMID:Novel sperm-binding proteins of epididymal origin contain four fibronectin type II-modules. 1114 25


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