Local synthesis of plasminogen by the seminiferous tubules of the testis

Saksela, Olli; Vihko, Kimmo K.

doi:10.1016/0014-5793(86)80810-9

Cited by 23 publications

(5 citation statements)

References 27 publications

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“…Plasminogen is an inactive zymogen mainly synthesized by the liver and at lesser extent in other tissues such as testes [ 31 , 32 ]. Its secretions are found in various extracellular fluids, including seminal plasma and oviductal fluids [ 33 , 34 ].…”

Section: Resultsmentioning

confidence: 99%

Self-illuminating quantum dots for non-invasive bioluminescence imaging of mammalian gametes

et al. 2015

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BackgroundThe fertility performance of animals is still a mystery and the full comprehension of mammalian gametes maturation and early embryonic development remains to be elucidated. The recent development in nanotechnology offers a new opportunity for real-time study of reproductive cells in their physiological environments. As a first step toward that goal, we evaluated the effectiveness of a fluorescent and luminescent nanoparticle for in vitro and ex vivo imaging of porcine gametes.MethodsFreshly harvested boar sperm were labeled with red-shifted (655 nm) quantum dot nanoparticles conjugated (QD+) or not (QD−) with plasminogen antibody and evaluated. Subsets of labeled spermatozoa were loaded into straws and placed within the lumen of gilt reproductive tracts for ex vivo intra-uterine imaging. Porcine cumulus-oocyte complexes (COCs) were matured in the presence of QD− or QD+. Ovarian follicles were microinjected with QD− or QD+ and placed in culture for up to 4 days. After labeling, all samples were supplemented with coelenterazine, the luciferase substrate, and immediately submitted to bioluminescence analysis, followed by fluorescence and hyperspectral imaging. Data were analyzed with ANOVA and P < 0.05 indicated significant differences.ResultsAll labeled-samples revealed bioluminescence emission that was confirmed by fluorescence and hyperspectral imaging of the QD localization within the cells and tissues. Over 76% of spermatozoa and both immature and mature COCs were successfully labeled with QD− or QD+. The QD− fluorescence appeared homogenously distributed in the oocytes, while found in the entire sperm length with a higher accumulation within the mid-piece. Labeled-follicles exhibited a progressive migration of QD nanoparticles within the follicle wall during culture. In contrast, QD+ fluorescence signals appeared condensed and stronger in the follicle cells, sperm head, and sub-plasma membrane area of mature oocytes. Weaker QD+ signals were detected in the cumulus cells. Fluorescence and hyperspectral microscope imaging showed comparable intracellular QD localization. Ex-vivo intra-uterine bioluminescence imaging of labeled spermatozoa revealed stronger signals captured over the oviducts, with uterine body allowing the lowest signal detection.ConclusionFindings indicate that conjugated and non-conjugated fluorescent nanoparticles can be used for effective labeling of mammalian gametes for in vitro monitoring and potential in vivo targeted-imaging.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-015-0097-1) contains supplementary material, which is available to authorized users.

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Section: Resultsmentioning

confidence: 99%

Self-illuminating quantum dots for non-invasive bioluminescence imaging of mammalian gametes

et al. 2015

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“…uPA is a serine protease that converts plasminogen into plasmin, a neutral protease of broad specificity . Plasminogen, which is abundant in plasma and other extracellular fluids, is also synthesized in seminiferous tubules (Saksela and Vihko, 1986), suggesting that it is present throughout the lumen of the male genital tract. While the precise role of uPA in the biology of the reproductive system has not been elucidated, the enzyme appears to be secreted around the time of ejaculation, and to bind, possibly through interaction with a specific cell surface receptor, to the head region of the murine spermatozoon (Huarte et al, 1987).…”

Section: Introductionmentioning

confidence: 99%

Protease-nexin I as an androgen-dependent secretory product of the murine seminal vesicle.

et al. 1993

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A search for inhibitors of urokinase-type plasminogen activator (uPA) in the male and female murine genital tracts revealed high levels of a uPA ligand in the seminal vesicle. This ligand is functionally, biochemically and immunologically indistinguishable from protease-nexin I (PN-I), a serpin ligand of thrombin and uPA previously detected only in mesenchymal cells and astrocytes. A survey of murine tissues indicates that PN-I mRNA is most abundant in seminal vesicles, where it represents 0.2-0.4% of the mRNAs. PN-I is synthesized in the epithelium of the seminal vesicle, as determined by in situ hybridization, and is secreted in the lumen of the gland. PN-I levels are much lower in immature animals, and strongly decreased upon castration. Testosterone treatment of castrated males rapidly restores PN-I mRNA levels, indicating that PN-I gene expression is under androgen control.

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“…In this context, the translocation of differentiating germ cells in the spermatogenic epithelium and/or their release from the epithelium into the lumen of seminiferous tubules may also be facilitated by expression of the uPAR. This suggestion is supported by the finding that plasminogen [22] and uPA [17][18][19] are expressed in seminiferous tubules. Alternatively, the uPAR may remain unoccupied until, presumably at the time of ejaculation, uPA is secreted by epithelial cells of the epididymis and the vas deferens [10].…”

Section: Discussionmentioning

confidence: 71%

The receptor for urokinase‐type plasminogen activator is expressed during mouse spermatogenesis

Zhou

Vassalli

1997

FEBS Letters

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Key words: uPA receptor; Germ cell; Spermatozoa; Local proteolysis be synthesized by epithelial cells from the caudal part of the epididymis and the vas deferens [10], and the binding of exogenous uPA to spermatozoa prepared from the vas deferens suggested the presence of uPAR [10]. However, because of difficulties in preparing spermatozoa that had not been exposed to epididymal or vas deferens secretions, the evidence for the presence of uPAR on spermatozoa was not unambiguous. We have thus re-investigated this issue, taking advantage of the availability of mice lacking uPA [11] and of molecular probes for murine uPAR mRNA [12]. Our results provide conclusive evidence that uPAR is synthesized by germ cells during spermatogenesis, and that it is present on spermatids and mature mouse spermatozoa. Together with the previously described presence of plasminogen-binding sites on these cells [13], these observations raise the question of the possible role(s) of the uPA-plasminogen system in spermatogenesis, spermatozoa maturation and/or fertilization.

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Local synthesis of plasminogen by the seminiferous tubules of the testis

Cited by 23 publications

References 27 publications

Self-illuminating quantum dots for non-invasive bioluminescence imaging of mammalian gametes

Self-illuminating quantum dots for non-invasive bioluminescence imaging of mammalian gametes

Protease-nexin I as an androgen-dependent secretory product of the murine seminal vesicle.

The receptor for urokinase‐type plasminogen activator is expressed during mouse spermatogenesis

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