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Follicle-stimulating hormone (FSH), a pituitary glycoprotein hormone, is an integral component of the endocrine axis that regulates gonadal function and fertility. To transmit its signal, FSH must bind to its receptor (FSHR) located on Sertoli cells of the testis and granulosa cells of the ovary. Thus, both the magnitude and the target of hormone response are controlled by mechanisms that determine FSHR levels and cell-specific expression, which are supported by transcription of its gene. The present review examines the status of FSHR/Fshr gene regulation, emphasizing the importance of distal sequences in FSHR/Fshr transcription, new insights gained from the influx of genomics data and bioinformatics, and emerging trends that offer direction in deciphering the FSHR/Fshr regulatory landscape.
Bacterial vaginosis is associated with a 1.4-fold increased risk of preterm birth. We have shown previously that Lactobacillus rhamnosus GR-1 supernatant up-regulates interleukin 10 and down-regulates tumor necrosis factor-alpha output in lipopolysaccharide (LPS)-treated human primary placenta cultures in a fetal sex-dependent manner. We hypothesize that lactobacilli also exert their anti-inflammatory effect by up-regulation of colony-stimulating factor 3 (granulocyte) (CSF3), which is secreted from both immune and placental trophoblast cells, and that this activity is dependent on the sex of the fetus. Placental trophoblast cells were isolated from term elective cesarean section placentae using a Percoll gradient and separated from CD45 cells using magnetic purification. Cells were treated with LPS in the presence or absence of pretreatments with L. rhamnosus GR-1 supernatant or chemical inhibitors of the intracellular signaling pathways. Phosphorylations of mitogen-activated protein kinase 14 (MAPK14, previously known as p38) and signal transducer and activator of transcription (STAT) 3 were measured by Western blot analysis, and levels of CSF3 were determined by ELISA. CSF3 output was increased only in the placental trophoblast cells of female fetuses treated with LPS, GR-1 supernatant, and a combination of both treatments. The GR-1 supernatant up-regulated the phosphorylation of STAT3 and MAPK14. CSF3 output was inhibited by both Janus kinases (JAK) and MAPK14 inhibitors. None of the treatments was able to increase CSF3 output in either the pure trophoblast or the CD45 cell preparations alone. These results suggest an underlying mechanism for the sex difference in incidence of preterm birth and provide potential evidence for a therapeutic benefit of lactobacilli in reducing the risk of preterm labor.
Prostaglandin F2alpha (PGF) causes luteolysis of the pig corpus luteum (CL) only after Day 12 of the estrous cycle. Recent evidence indicates that progesterone (P4) may protect the CL from cell death. The present study tested the hypothesis that acute inhibition of P4 by treatment with epostane (EPO; 3betaHSD inhibitor) in CL lacking luteolytic capacity (Day 9 CL) will allow PGF to induce responses associated with luteolysis. Multiple PGF-induced responses were evaluated, including genes involved in production of PGF and estradiol-17beta, apoptosis (caspase 3), and transcription (FOSB). These responses are associated with PGF-induced luteolysis and do not normally occur in CL lacking luteolytic capacity. Animals on Day 7 after estrus were divided into four groups: 1) control (C), 2) PGF, 3) EPO, and 4) PGF plus EPO (PGF EPO). Treatment with EPO (10 mg/kg) or vehicle was given every 12 h for 36 h. Treatment with PGF (25 mg) or vehicle was given at 38 h, and CL were collected from all animals at 48 h. Some CL from each animal were frozen in liquid nitrogen for mRNA and protein analysis. Remaining CL were incubated in media for 2 h for determination of P4 and PGF production. EPO dramatically decreased production of P4 by luteal tissue (ng/mg tissue) by 90% and 95% in EPO and PGF EPO groups, respectively, compared to C (P < 0.01). Low production of PGF by luteal tissue was found in C, PGF, and EPO groups; however, treatment with PGF EPO dramatically increased (782%) luteal PGF production. Similar to intraluteal PGF production, increased mRNA for cyclooxygenase 2 (PTGS2) and phospholipase A2 (group IB; PLA2G1B) was found in the PGF EPO, but not in the EPO or PGF, group. Aromatase (CYP19A1) mRNA was not induced by PGF or EPO; however, PGF EPO caused a more than 40-fold increase in CYP19A1 mRNA (P < 0.01). CASP3 mRNA was increased (P < 0.01) by EPO (3.4-fold) and by PGF (2.7-fold) but was most dramatically increased by PGF EPO (5.3-fold), whereas caspase activity was only increased by PGF (1.5-fold) or PGF EPO (2.2-fold). Thus, these data support the hypothesis that elimination of the protective effect of intraluteal P4 does not directly cause luteolysis of the early CL but allows PGF to induce luteolytic responses in CL lacking luteolytic capacity.
Meiosis is unique to germ cells and occurs in a sex-specific manner. The genes regulating meiotic initiation in either sex are yet to be fully elucidated. Recent studies have revealed the importance of retinoic acid and one of its target genes, Stra8, in meiotic initiation in both sexes. Microarray analysis of whole murine embryonic ovary and postnatal testis time course data revealed a single peak of Stra8 expression in each organ at the onset of meiosis; at Embryonic Day 14.5 in the ovary and 10 days postpartum in the testis. In order to identify other genes involved in the initiation of meiosis in mammals, murine testis and ovary microarray data were examined more closely for transcripts with expression profiles similar to Stra8. Three such candidates include establishment of cohesion 1 homolog 2 (Esco2), encoding a protein essential for sister chromatid cohesion; SET domain, bifurcated 2 (Setdb2), the mouse ortholog of Eggless, which is essential for oogenesis in Drosophila; and ubiquitin-activating enzyme 6 (Uba6), a gene with fivefold higher expression in human and mouse testes than any other organ. In situ hybridization and immunohistochemistry or immunofluorescence were performed to localize Esco2, Setbd2, and Uba6 expression in the developing testis. The cellular expression pattern localized all three of these transcripts and their respective proteins to germ cells transitioning from mitosis to meiosis, hence supporting the hypothesis of their involvement in the initiation of meiosis. Future research will be directed at determining a specific role for these three proteins in germ cell differentiation.
The early bovine preimplantation embryo is resistant to proapoptotic signals until around the 8- to 16-cell stage. We hypothesized that 2-cell embryos have higher amounts of antiapoptotic proteins and lower amounts of proapoptotic proteins when compared to embryos ≥16 cells. Steady-state concentrations of mRNA for the antiapoptotic genes BCL2 and HSPA1A were higher for MII oocytes, 2-cell embryos, and 2-cell embryos treated with alpha-amanitin as compared to ≥16-cell embryos. Steady-state concentrations of mRNA for the proapoptotic gene BAD increased in embryos ≥16 cells. There was no significant effect of stage of development on steady-state mRNA concentrations of BCL2L1, DFFA, or BAX. Using immunohistochemistry, it was found that BCL2 was present in greater relative concentrations for 2-cell embryos than for embryos ≥16 cells. These results were confirmed by Western blotting. Relative amounts of immunoreactive BAX detected by immunofluorescence were lower for 2-cell embryos than for embryos ≥16 cells. Using Western blotting, a high molecular weight (46 kDa) form of BAX was highest in ≥16-cell embryos, intermediate in 2-cell embryos, and lowest in MII oocytes. There were no effects of stage of development on relative amounts of immunoreactive BCL2L1, HSPA1A, or BAD, as determined by immunofluorescence. Treatment of embryos with alpha-amanitin from Day 0 to Day 5 or Day 4 to Day 5 after insemination reduced activation of group II caspases and terminal deoxynucleotidyl transferase dUTP nick end labeling after treatment with the proapoptotic signal C2 ceramide at Day 5 after fertilization. Thus, transcription of BAX or other proteins is required for acquisition of the capacity for apoptosis. Results support the idea that changes in amounts of BCL2 family members are important for the inhibition of apoptosis in the 2-cell embryo and in the establishment of the capacity for apoptosis later in development.
Estrogen plays a key role in maintaining the morphology and function of the efferent ductules. We previously demonstrated that the antiestrogen fulvestrant markedly affected gene expression in the rat efferent ductules. The mechanism of fulvestrant action to modulate gene expression may involve not only the blockade of ESR1 and ESR2 estrogen receptors, but also the activation of ESR1 and ESR2 when the receptors are tethered to AP-1 or SP1 transcription factors, or the activation of the G protein-coupled estrogen receptor 1. We therefore compared the effects of two strategies to interfere with estrogen action in the rat efferent ductules: treatment with fulvestrant or with the aromatase inhibitor anastrozole. Whereas fulvestrant markedly increased Mmp7 and Spp1, and reduced Nptx1 mRNA levels, no changes were observed with anastrozole. Fulvestrant caused changes in epithelial morphology that were not seen with anastrozole. Fulvestrant shifted MMP7 immunolocalization in the epithelial cells from the supranuclear to the apical region; this effect was less pronounced with anastrozole. In vitro studies of 35S-methionine incorporation showed that protein release was increased, whereas tissue protein content in the efferent ductules of fulvestrant-treated rats was decreased. Although fulvestrant markedly affected gene expression, no changes were observed on AP-1 and SP1 DNA-binding activity. The blockade of ESRs seems to be the major reason explaining the differences between both treatments. At least some of the effects of fulvestrant appear to result from compensatory mechanisms activated by the dramatic changes caused by ESR1 blockade.
Histotroph is required for survival and development of ovine conceptuses (embryo and extraembryonic membranes). Results from our laboratory indicate that arginine (Arg), leucine (Leu), glutamine (Gln), and glucose increase in the uterine lumen between Days 10 and 15 of pregnancy, coincident with increases in expression of amino acid and glucose transporters by uterine epithelia as well as trophectoderm and yolk sac of conceptuses and elongation of the conceptus trophectoderm. Therefore, we hypothesized that Arg, Leu, Gln, and glucose have differential effects on hypertrophy, hyperplasia, and differentiated functions of trophectoderm cells that are critical to conceptus development. Primary ovine trophectoderm (oTr) cells isolated from Day 15 conceptuses were serum-starved for 24 h in a customized medium, deprived of select nutrients, and then treated with either Arg, Leu, Gln, or glucose. Western blot analyses of whole oTr cell extracts revealed that Arg, Leu, and glucose, but not Gln, increased phosphorylated AKT1 by 2.8-, 2.5-, and 1.8-fold, respectively, within 15 min, and the increase was maintained to 60 min. Arg, Leu, and glucose also stimulated increases in phosphorylated ribosomal protein S6K (pRPS6K) by 4.2-, 4.7-, and 2.3-fold, respectively, within 15 min, as well as increases in phosphorylated ribosomal protein S6 (pRPS6) between 0 and 30 min posttreatment, that were sustained to 60 min. When oTr cells were treated with Arg, pRPS6K protein increased in nuclei, but this was not observed in nuclei of oTr cells treated with Leu and glucose. Immunocytochemical analyses also revealed abundant amounts of pRPS6 protein in the cytoplasm of oTr cells treated with Arg, Leu, and glucose. Furthermore, Arg and Leu increased proliferation and migration of oTr cells. Collectively, these results indicate that Arg, Leu, and glucose, but not Gln, in histotroph coordinately activate AKT1-mechanistic target of rapamycin and RPS6K-RPS6 cell signaling pathways to stimulate hypertrophy, hyperplasia, and migration of oTr cells.
During the peri-implantation period in sheep, l-arginine (l-Arg) in the uterine lumen is an essential substrate for the synthesis of nitric oxide (NO), by nitric oxide synthase (NOS), and polyamines, via arginase and ornithine decarboxylase, that are required for survival and development of ovine conceptuses (embryo and its extraembryonic membranes). l-Arginine can stimulate hypertrophy, hyperplasia, and differentiation of the ovine conceptus trophectoderm; however, the responsible signal transduction cascade has not been determined. Therefore, this study examined possible signaling pathways mediated by l-Arg, as well as the effects of two NO donors (S-nitroso-N-acetyl-dl-penicillamine and diethylenetriamine) and putrescine (precursor for spermidine and spermine) on oTr cell proliferation. Further, the inhibition of these effects by l-NAME (l-nitro-arginine methyl ester, an inhibitor of NOS) and nor-NOHA (N-omega-hydroxy-nor-arginine, an inhibitor of arginase) was assessed. l-Arginine treatment increased the abundance of phosphorylated MTOR, RPS6K, and EIF4EBP1 in oTr cells. Consistent with activation of these cell-signaling molecules, l-Arg increased protein synthesis and reduced protein degradation in oTr cells. Both NO and polyamines enhanced cell proliferation in a dose-dependent manner. The effects of l-Arg were partially inhibited by both l-NAME and nor-NOHA. These results indicate that l-Arg enhances production of polyamines and NO and activates the MTOR/FRAP1-RPS6K-RPS6 signaling pathway to stimulate proliferation and migration of oTr cells.
Evidence from experimental studies suggests that fetal exposure to the endocrine-disrupting chemical bisphenol A (BPA) has adverse reproductive effects in both males and females. Studies from our laboratory suggest that exposure to the developing female fetus produces a unique, multigenerational effect. Specifically, maternal exposure affects the earliest stages of oogenesis in the developing fetal ovary, and the resulting subtle meiotic defects increase the likelihood that embryos produced by the exposed female in adulthood (i.e., the grandchildren) will be chromosomally abnormal. To understand the impact of BPA on the developing ovary, we conducted expression studies to characterize gene expression changes in the fetal ovary that result from BPA exposure. We first tested the validity of the approach, asking whether we could reliably detect temporal changes in expression levels of meiotic genes in controls. As anticipated, we were able to identify appropriate increases in expression in meiotic, but in few other, genes. Intriguingly, this analysis provided data on a small set of genes for which timing and expression changes suggest that they may have important and heretofore unrecognized meiotic roles. After verifying the utility of our approach, we focused our analysis on BPA-exposed animals. We found modest, but significant, changes in gene expression in the fetal ovaries from exposed fetuses. The first changes were evident within 24 h of exposure, and the most extensive changes correlated with the onset of meiosis. Furthermore, gene ontology analysis suggested that BPA acts to down-regulate mitotic cell-cycle genes, raising the possibility that fetal BPA exposure may act to limit expansion of the primordial germ cell population.
Almudena Veiga-Lopez, Teresa L. Steckler, David H. Abbott, Kathleen B. Welch, Puliyur S. MohanKumar, David J. Phillips, Kent Refsal, Vasantha Padmanabhan
Prenatal testosterone excess in sheep leads to reproductive and metabolic disruptions that mimic those seen in women with polycystic ovary syndrome. Comparison of prenatal testosterone-treated sheep with prenatal dihydrotestosterone-treated sheep suggests facilitation of defects by androgenic as well as androgen-independent effects of testosterone. We hypothesized that the disruptive impact of prenatal testosterone on adult pathology may partially depend on its conversion to estrogen and consequent changes in maternal and fetal endocrine environments. Pregnant Suffolk sheep were administered either cottonseed oil (control) or testosterone propionate in cottonseed oil (100 mg, i.m. twice weekly), from Day 30 to Day 90 of gestation (term is ∼147 d). Maternal (uterine) and fetal (umbilical) arterial samples were collected at Days 64–66, 87–90, and 139–140 (range; referred to as D65, D90, and D140, respectively) of gestation. Concentrations of gonadal and metabolic hormones, as well as differentiation factors, were measured using liquid chromatography/mass spectrometer, radioimmunoassay, or ELISA. Findings indicate that testosterone treatment produced maternal and fetal testosterone levels comparable to adult males and D65 control male fetuses, respectively. Testosterone treatment increased fetal estradiol and estrone levels during the treatment period in both sexes, supportive of placental aromatization of testosterone. These steroidal changes were followed by a reduction in maternal estradiol levels at term, a reduction in activin A availability, and induction of intrauterine growth restriction in D140 female fetuses. Overall, our findings provide the first direct evidence in support of the potential for both androgenic as well as estrogenic contribution in the development of adult reproductive and metabolic pathology in prenatal testosterone-treated sheep.
Spermatogonial stem cells (SSCs) undergo self-renewal divisions to support spermatogenesis. Although several in vitro SSC culture systems have been developed, these systems include serum or fibroblast feeders, which complicate SSC self-renewal analyses. Here, we developed a serum- and feeder-free culture system for long-term propagation of SSCs. In addition to the SSC self-renewal factors, including glial cell line-derived neurotrophic factor, supplementation with fetuin and lipid-associated molecules was required to drive SSC proliferation in vitro. Cultured cells proliferated for at least 6 mo at a rate comparable to that of serum-supplemented cultured cells. However, germline potential was reduced under serum- and feeder-free conditions, as indicated by a lower SSC frequency after germ cell transplantation. Nevertheless, the cultured cells completed spermatogenesis and produced offspring following spermatogonial transplantation into seminiferous tubules of infertile mice. This culture system provides a basic platform for understanding the regulation of SSC fate commitment in vitro and for improving SSC culture medium.
Endometriosis is a common gynecologic disorder characterized by ectopic attachment and growth of endometrial tissues. Resveratrol is a natural polyphenol with antiproliferative and anti-inflammatory properties. Our objective was to study the effects of resveratrol on human endometriotic implants in a nude mouse model and to examine its impact on human endometrial stromal (HES) cell invasiveness in vitro. Human endometrial tissues were obtained from healthy donors. Endometriosis was established in oophorectomized nude mice by intraperitoneal injection of endometrial tissues. Mice were treated with 17β-estradiol (8 mg, silastic capsule implants) alone (n = 16) or with resveratrol (6 mg/mouse; n = 20) for 10–12 and 18–20 days beginning 1 day after tissue injection. Mice were killed and endometrial implants were evaluated. A Matrigel invasion assay was used to examine the effects of resveratrol on HES cells. We assessed number and size of endometriotic implants in vivo and Matrigel invasion in vitro. Resveratrol decreased the number of endometrial implants per mouse by 60% (P < 0.001) and the total volume of lesions per mouse by 80% (P < 0.001). Resveratrol (10–30 μM) also induced a concentration-dependent reduction of invasiveness of HES by up to 78% (P < 0.0001). Resveratrol inhibits development of endometriosis in the nude mouse and reduces invasiveness of HES cells. These observations may aid in the development of novel treatments of endometriosis.
Although the neuromedin B receptor (NMBR), a bombesin receptor family member, has been implicated in thermoregulation and in stimulation of both urogenital and gastrointestinal smooth muscle contraction, its underlying role in labor onset and its associated molecular mechanisms remain poorly understood. We examined the relationship between temporal and spatial NMBR expression in the myometrium of pregnant mice and potential mechanistic pathways leading to labor onset. Resultant data indicate that NMBR expression peaked at term and before parturition. Maternal exposure to the NMBR agonist neuromedin B (NMB) shortened the gestational age of pups, an effect that was also observed after oxytocin administration. Both RELA (NFKB P65) DNA-binding activity and interleukin 6 (Il6) mRNA expression were greatest during parturition and after maternal exposure to the highest NMB concentration administered (150 μg/kg). Furthermore, a significant correlation was observed among NMBR mRNA expression, RELA DNA-binding activity, and Il6 mRNA expression. These data demonstrate that NMB and its receptor can induce the onset of labor via a RELA/IL6-mediated pathway.
Thyronines are essential for the development of the male reproductive system, including the prostate gland. Metabolically active 3,5,3′ triiodothyronine (T3) is generated mainly by the extrathyroidal, enzymatic 5′deiodination of the prohormone thyroxine (T4), which is catalyzed by deiodinases type 1 (D1) and type 2 (D2). Prostate D1 activity is highly expressed during puberty and declines with age, but continuous, long-term sexual activity prevents this reduction. The aims of this study were to characterize the changes in prostatic D1 activity in response to consecutive ejaculations and to determine whether sympathetic input participates in the local T3 generation (D1 activity). D1 activity was analyzed in prostates of sexually experienced, 4-mo-old male rats after one to five ejaculations. D1 activity, T3 concentrations, and the T3-dependent gene ornithine decarboxylase (Odc) were measured after the fourth ejaculation in prostates of intact, sham, and sympathectomized (Smpx, hypogastric nerve) rats. D1 activity was evaluated by the radio-iodine-release method; T3 was measured by radioimmunoassay and Odc expression by real-time PCR. Data showed a gradual increase of prostate D1 activity in response to consecutive ejaculations. The highest activity was found after the fourth ejaculation, and it decreased after the fifth. The increase of prostate D1 activity after ejaculation was blocked in Smpx males as compared to intact or sham animals. The changes in D1 activity correlate with prostatic T3 concentrations and Odc expression. Circulating levels of T3 were not affected by consecutive ejaculations or by Smpx. These findings indicate that the postejaculatory increase in prostatic generation of T3 depends on sympathetic input.
In mammals, the duration of the cycle of the seminiferous epithelium (DCSE) largely differs between species, but is remarkably stable within a species, usually showing variations of 1%–3%. It is difficult to change the DCSE, e.g., by hormones or chemicals. Initial experiments, employing quantitative RT-PCR, aimed at investigating the diurnal profiles of the clock genes Arntl (previously called Bmal1) and Per1 in testes and kidneys of Djungarian hamsters (Phodopus sungorus). While the testicular levels of Arntl were almost constant, clear diurnal variations were identified for Per1. In order to clarify whether day length (T-cycle) is a factor for DSCE, adult male hamsters (n = 20 per group) were exposed to normal (T = 24 h), prolonged (T = 25 h), or shortened (T = 23 h) T-cycles, with cycles thus being longer or shorter by 4.2% compared to the normal condition. Exposure lasted for 43 days, during which the activity of the animals was recorded to confirm entrainment. DCSE was estimated by incorporation of bromodeoxyuridine in dividing cells and the immunohistochemical localization of labeled cells in stages I–XII of the seminiferous epithelium. Despite the low variability of the results and the close agreement with previously published data, no effects of prolonged or shortened T-cycles on DCSE could be identified (24 h: 7.98 ± 0.05 days; 23 h: 7.94 ± 0.04 days; 25 h: 7.91 ± 0.03 days; P > 0.05). The results strongly indicate that the high temporal precision of spermatogenesis is independent of the central circadian clock.
Establishment of pregnancy in the pig depends on down-regulation of progesterone receptor (PGR) in the uterine luminal and glandular epithelium during the first week after breeding. The present study evaluated the regulation of endometrial PGR by progesterone and the possible role of endometrial tumor necrosis factor (ligand) superfamily member 11 (TNFSF11) and nuclear factor-kappa B (NFKB) activation in PGR expression. Mature, cycling gilts were inseminated (Day 0) and assigned to either untreated control (n = 9) or one of two treatments that employed RU 486 to block progesterone action either before (treatment 1 [T1]) or after (treatment 2 [T2]) the initiation of PGR down-regulation. The T1 gilts were treated with RU 486 (400 mg/day) on Days 3–5 of pregnancy (n = 9), and T2 gilts were treated with RU 486 on Days 6 and 7 of pregnancy (n = 9). Uteri and ovaries were collected on Day 8 or 12 of gestation. The diameter of the conceptuses in T1 gilts was approximately half that in controls by Day 8, and normal conceptuses were not collected from any T1 gilts on Day 12. Endometrial PGR mRNA was more abundant in T1 and T2 gilts compared with control gilts. The PGR-B protein decreased from Day 8 to Day 12 in the luminal epithelium and, to some extent, in superficial glandular epithelium in control and T2 gilts. In T1 gilts, the PGR-B protein remained elevated (i.e., failed to undergo down-regulation) on Day 12. Blocking PGR action early in the cycle (i.e., on or before Day 5), therefore, prevented normal conceptus development, caused elevated PGR mRNA, and prevented the decrease in PGR protein that typically occurs in pigs. We could not confirm a role for NFKB activation in PGR down-regulation, because pigs with extreme differences in PGR and TNFSF11 expression (T1 and controls) had similar NFKB activation on Day 8. Activated NFKB within the luminal epithelium and glandular epithelium (both superficial and deep) was observed in T2 and control pigs on Day 12 when elongating conceptuses (presumably releasing interleukin 1 beta to activate NFKB) were recovered. Gilts treated with RU 486 had greater ovarian follicular growth and greater plasma estradiol concentrations. We conclude that the mechanisms controlling PGR down-regulation are progesterone-dependent and occur between Day 3 and Day 6 of pregnancy. NFKB activation did not appear to have a role in PGR down-regulation within the period that we studied. Blocking progesterone action after Day 6 did not reverse the process of PGR down-regulation, nor did it appear to affect the development of conceptuses collected on Day 12.
The cystatin CRES (cystatin-related epididymal spermatogenic; Cst8) is the defining member of a reproductive subgroup of family 2 cystatins of cysteine protease inhibitors and is present in the epididymis and spermatozoa, suggesting roles in sperm maturation and fertilization. To elucidate the role of CRES in reproduction, mice lacking the Cst8 gene were generated and their fertility examined. Although both male and female Cst8−/− mice generated offspring in vivo, spermatozoa from Cst8−/− mice exhibited a profound fertility defect in vitro. Compared to spermatozoa from Cst8 / mice, spermatozoa from Cst8−/− mice were unable to undergo a progesterone-stimulated acrosome reaction and had decreased levels of protein tyrosine phosphorylation, suggesting a defect in the ability of Cst8−/− spermatozoa to capacitate. Incubation of Cst8−/− spermatozoa with dibutyryl cAMP and 3-isobutyl-1-methylxanthine rescued the fertility defect, including the capacity for sperm protein tyrosine phosphorylation. Both untreated Cst8 / and Cst8−/− spermatozoa, however, exhibited similar increased total levels of cAMP and protein kinase A (PKA) activity throughout the capacitation time course compared to spermatozoa incubated under noncapacitating conditions. Taken together, these results suggest that mice lacking CRES may have altered local levels of cAMP/PKA activity, perhaps because of improper partitioning or tethering of these signaling molecules, or that the CRES defect does not directly involve cAMP/PKA but other signaling pathways that regulate protein tyrosine phosphorylation and capacitation.
The Na,K-ATPase alpha4 (ATP1A4) isoform is specifically expressed in male germ cells and is highly prevalent in spermatozoa. Although selective inhibition of alpha4 activity with ouabain has been shown to affect sperm motility, a more direct analysis of the role of this isoform in sperm movement has not yet been demonstrated. To establish this, we engineered transgenic mice that express the rat alpha4 isoform fused to green fluorescent protein in male germ cells, under the control of the mouse protamine 1 promoter. We showed that the rat Atp1a4 transgene is expressed in mouse spermatozoa and that it is localized to the sperm flagellum. In agreement with increased expression of the alpha4 isoform, sperm from transgenic mice displayed higher alpha4-specific Na,K-ATPase activity and binding of fluorescently labeled ouabain than wild-type mice. In contrast, expression and activity of ATP1A1 (alpha1), the other Na,K-ATPase alpha isoform present in sperm, remained unchanged. Similar to wild-type mice, mice expressing the alpha4 transgene exhibited normal testis and sperm morphology and no differences in fertility. However, compared to wild-type mice, sperm from transgenic mice displayed plasma membrane hyperpolarization and higher total and progressive motility. Other parameters of motility also increased, including straight-line, curvilinear, and average path velocities and amplitude of lateral head displacement. In addition, sperm from the transgenic mice showed enhanced sperm hyperactive motility, but no changes in progesterone-induced acrosome reaction. Altogether, these results provide new genetic evidence for the role of the ATP1A4 isoform in sperm motility, under both noncapacitating and capacitating conditions.
Regulation of growth of ovarian theca-interstitial tissues is essential for normal ovarian development and function. Reactive oxygen species are involved in modulation of signal transduction pathways, including regulation of tissue growth and apoptosis. Previously, we have demonstrated that antioxidants inhibit proliferation of theca-interstitial cells. This report evaluates the effects of antioxidants on apoptosis of rat theca-interstitial cells. The cells were cultured in chemically defined media without or with vitamin E succinate and ebselen. Apoptosis was evaluated by cytochemical assessment of nuclear morphology, activity of executioner caspases 3 and 7, and determination of staining with annexin V in combination with propidium iodide. Both tested antioxidants induced significant morphological changes consistent with apoptosis, including chromatin condensation, nuclear shrinkage, and pyknosis. Antioxidants also induced other hallmarks of apoptosis including increased activity of caspases 3/7 as well as increased staining with annexin V. The present findings demonstrate that antioxidants with distinctly different mechanisms of action induce a series of events consistent with the process of apoptosis in ovarian mesenchyme. These observations may be of translational-clinical relevance, providing mechanistic support for the use of antioxidants in the treatment of PCOS, a condition associated with excessive growth and activity of theca-interstitial cells.
Human sirtuin (SIRT) 1 and SIRT2, which possess nicotinamide adenosine dinucleotide (NAD)-dependent deacetylase activity, exhibit anti-inflammatory actions. However, there are no data available on SIRT1 and SIRT2 expression and regulation in human intrauterine tissues. Thus, the aim of this study was to characterize the localization and expression of SIRT1 and SIRT2 in 1) placenta and fetal membranes before and after term spontaneous labor onset, 2) prelabor fetal membranes from the supracervical site (SCS) and a distal site (DS), and 3) in response to proinflammatory stimuli. Further, the effect of SIRT activation using resveratrol and SRT1720 on prolabor mediators was also assessed. SIRT1 and SIRT2 were localized in the syncytiotrophoblast layer and the cytotrophoblasts of the placenta, amnion epithelium, trophoblast layer of the chorion, and decidual cells. Additionally, SIRT2 was found within the endothelial walls of placental vessels. SIRT2, but not SIRT1, staining was significantly lower in amnion and chorion obtained from the SCS compared to a DS. On the other hand, SIRT1, but not SIRT2, gene and/or protein expression was significantly lower in placenta, amnion, and chorion obtained after labor compared to prelabor. SIRT1 expression, but not SIRT2, was down-regulated by lipopolysaccharide (LPS) and proinflammatory cytokines TNF and IL1B. The SIRT1 activators resveratrol and SRT1720 significantly decreased LPS-induced TNF, IL6, and IL8 gene expression and release and PTGS2 mRNA expression and resultant prostaglandin (PG) E2 and PGF2α release from human gestational tissues. In conclusion, SIRT1 possesses anti-inflammatory actions and thus may play a role in regulating pregnancy and parturition.
Macrophages accumulate within stromal tissue subjacent to the luminal epithelium in the mouse uterus during early pregnancy after seminal fluid exposure at coitus. To investigate their role in regulating epithelial cell expression of fucosylated structures required for embryo attachment and implantation, fucosyltransferase enzymes Fut1, Fut2 (Enzyme Commission number [EC] 2.4.1.69), and Fut4 (EC 2.4.1.214) and Muc1 and Muc4 mRNAs were quantified by quantitative real-time PCR in uterine epithelial cells after laser capture microdissection in situ or after epithelial cell coculture with macrophages or macrophage-secreted factors. When uterine macrophage recruitment was impaired by mating with seminal plasma-deficient males, epithelial cell Fut2 expression on Day 3.5 postcoitus (pc) was reduced compared to intact-mated controls. Epithelial cell Fut2 was upregulated in vitro by coculture with macrophages or macrophage-conditioned medium (MCM). Macrophage-derived cytokines LIF, IL1B, and IL12 replicated the effect of MCM on Fut2 mRNA expression, and MCM-stimulated expression was inhibited by anti-LIF and anti-IL1B neutralizing antibodies. The effects of acute macrophage depletion on fucosylated structures detected with lectins Ulex europaeus 1 (UEA-1) and Lotus tetragonolobus purpureas (LTP), or LewisX immunoreactivity, were quantified in vivo in Cd11b-dtr transgenic mice. Depletion of macrophages caused a 30% reduction in luminal epithelial UEA-1 staining and a 67% reduction in LewisX staining in uterine tissues of mice hormonally treated to mimic early pregnancy. Together, these data demonstrate that uterine epithelial Fut2 mRNA expression and terminal fucosylation of embryo attachment ligands is regulated in preparation for implantation by factors including LIF and IL1B secreted from macrophages recruited during the inflammatory response to insemination.
Jong-Yi Park, Mi-Ryung Park, Kyu-Chan Hwang, Ji-Seok Chung, Hong-Thuy Bui, Teoan Kim, Seong-Keun Cho, Jae-Hwan Kim, Seongsoo Hwang, Soo-Bong Park, Van Thuan Nguyen, Jin-Hoi Kim
Gene expression profiling of compromised umbilical cords (CUCs) derived from somatic cell nuclear transfer (scNT) clones was performed to determine why scNT-derived clones often exhibit malformed umbilical arteries. Umbilical cord samples were obtained from 65 scNT piglets, and of these, nine displayed a CUC. Microscopic analyses of the scNT clones with CUCs (scNT-CUCs) revealed complete occlusive thrombi that were not detected in the arteries of scNT clones with normal umbilical cords (scNT-Ns). Moreover, whereas the allantoic ducts of the scNT-Ns contained columnar epithelium, the scNT-CUCs lacked this epithelial layer. Compared to scNT-Ns, the scNT-CUCs exhibited severe histological damage, including tissue swelling and vein and arterial damage with complete occlusive thrombi. To investigate functional abnormality, gene expression profiles were created in duplicate using the Platinum Pig 13K oligonucleotide microarray, which contains 13 610 probes of 70 bp in length and is capable of interrogating 13 297 targets with up to one probe per target. Probe sets were selected according to a 2-fold or greater increase or decrease of gene expression in scNT-CUCs compared to scNT-Ns. Most genes expressed in scNT-Ns were also expressed by scNT-CUCs. However, most genes involved in transcriptional regulation, such as JUN, JUNB, and FOSL2, showed a significant decrease in expression in the scNT-CUCs, which may produce a ripple effect capable of altering the transcriptomes of many other cellular processes, including angiogenesis, antioxidation, and apoptosis. The scNT-CUCs with thrombosis showed extensive apoptosis leading to placental insufficiency and related pathology. Considering that the umbilical cord plays a role in the transportation of metabolites to the fetus, placental insufficiency in scNT-CUCs may be caused by an increase in apoptotic protein expression from scNT-derived umbilical cords with hypoplastic arteries, and our results provide evidence that porcine oligonucleotide microarray analysis is a useful tool for screening scNT-derived abnormalities in pigs.
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