Expression and localization of Aquaporin 3 (AQP3) in folliculogenesis of ewes

5-Fluorouracil disrupts ovarian preantral follicles in young C57BL6J mice

PURPOSE

5-Fluorouracil (5-FU), an anti-cancer drug, has been used for hepatoblastoma (HB) chemotherapy in children, who may have impaired  ovarian follicle pool reserve with lasting effects to reproduction. Therefore, this study aimed to investigate 5-FU effects on survival, growth, and morphology of ovarian preantral follicles from C57BL6J young mice.

METHODS

Experiments were carried-out both in vivo and in vitro. Mice were treated with 5-FU injection (450 mg/kg i.p) or saline and sacrificed 3 days after to obtain ovaries for histology and molecular biology. Ovaries for in vitro studies were obtained from unchallenged mice and cultured under basic culture medium (BCM) or BCM plus 5-FU (9.2, 46.1, 92.2 mM). Preantral follicles were classified according to developmental stages, and as normal or degenerated. To assess cell viability, caspase-3 immunostaining was performed. Transcriptional levels for apoptosis (Bax, Bcl2, p53, Bax/Bcl2) and Wnt pathway genes (Wnt2 and Wnt4) were also analyzed. Ultrastructural analyses were carried-out on non-cultured ovaries. In addition, β-catenin immunofluorescence was assessed in mouse ovaries.

RESULTS

The percentage of all-types normal follicles was significantly lower after 5-FU challenge. A total loss of secondary normal follicles was found in the 5-FU group. The highest 5-FU concentrations reduced the percentage of cultured normal primordial follicles. Large vacuoles were seen in granulosa cells and ooplasm of preantral follicles by electron microscopy. A significantly higher gene expression for Bax and Bax/Bcl2 ratio was seen after 5-FU treatment. A marked reduction in β-catenin immunolabeling was seen in 5-FU-challenged preantral follicles. In the in vitro experiments, apoptotic and Wnt gene transcriptions were significantly altered.

CONCLUSION

Altogether, our findings suggest that 5-FU can deleteriously affect the ovarian follicle reserve by reducing preantral follicles survival.

Impacts of different synthetic polymers on vitrification of ovarian tissue

Type and concentration of cryoprotective agents (CPAs) are important factors which influence the likelihood of a successful ovarian tissue vitrification outcome. In an attempt to address this factor, the present study was conducted to evaluate the impacts of different synthetic polymers (Supercool X-1000, Supercool Z-1000 and PVP K-12) on vitrification of bovine ovarian tissue. From each ovarian pair, fragments were recovered and immediately fixed for analysis (fresh control) or submitted to vitrification, either or not followed by in vitro culture for one or five days. Vitrification was performed using the ovarian tissue cryosystem (OTC) system. The ovarian tissues were intended for histological and viability analysis [Reactive oxygen species (ROS) production and degenerate cells assay (Ethidium homodimer-1)], as well as immunolocalization of AQP3 and AQP9 were measured. The results showed that during almost all the periods after warming, in treatment groups which contain polymer (X-1000, Z-1000 and PVP), the percentage of morphologically normal follicles was the highest in the X-1000 samples. Furthermore, post-thawed X-1000 group revealed stronger labeling for AQP9 in primordial and transitional follicles, when compared with others. However, morphology after cryopreservation did not correlate with follicle viability and function where the levels of degeneration and tissue damage of PVP K-12 group were lower in comparison with X-1000 group and only in PVP K-12 group, ROS level was similar to that of the fresh control group. We believe that in addition to permeating CPAs, the addition of one (Supercool X-1000) or maybe a combination (Supercool X-1000 and PVP K-12) of non-permeating polymers could be useful to improve the outcome for vitrified bovine ovarian tissue.

Immunolocalization for glucocorticoid receptor and effect of cortisol on in vitro development of preantral follicles

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In this study, the immunolocalization for glucocorticoid receptor (NR3C1) in goat ovarian follicles and the effect of cortisol on in vitro development of preantral follicles was evaluate.

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The NR3C1 was strongly expressed in oocytes of primary and antral follicles.

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A progressive increase of immunostaining for NR3C1 in granulosa cells from primordial to antral follicles was observed.

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In conclusion, it was observed the presence of NR3C1 in the oocyte and granulosa cells in all follicular categories.

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The in vitro culture showed that high cortisol concentration (10 ng/ml) exerts a deleterious effect on follicular survival.

The aim of this study was to evaluate the immunolocalization for glucocorticoid receptor (NR3C1) in goat ovarian follicles and the effect of cortisol on in vitro development of preantral follicles. Goat ovarian fragments were cultured for 7 days under different cortisol concentrations (0, 1, 5 and 10 ng/ml). Before and after culture, the protein expression of NR3C1 was analyzed in ovarian tissue by immunohistochemical analysis. Moreover, the endpoints follicular morphology, viability, activation as well as follicular and oocyte diameter were also analyzed. The NR3C1 was strongly expressed in oocytes of primordial and antral follicles. A progressive increase of immunostaining for NR3C1 in granulosa cells from primordial to antral follicles was observed regardless of the treatment. After in vitro culture, it was observed a significant reduction in the rate of normal preantral follicles rate in the 10 ng/ml cortisol treatment when compared to the other treatments. Moreover, follicular and oocyte diameter significantly decreased in all treatments (cortisol 0, 1, 5 and 10 ng/ml) compared to the fresh control. After culture, the activation rate significantly increased when the follicles were exposed to 1, 5 and 10 ng/ml cortisol compared to the fresh control. In conclusion, it was observed the presence of NR3C1 in the oocyte and granulosa cells in all follicular categories, except in granulosa cells of primordial follicles. The in vitro culture showed that high cortisol concentration (10 ng/ml) exerts a deleterious effect on follicular survival.

Effect of aquaporin 3 knockdown by RNA interference on antrum formation in sheep secondary follicles cultured in vitro

SummaryThe objectives were to develop an effective protocol for transfection of ovine secondary follicles and to assess the effect of attenuating aquaporin 3 (AQP3) using a small interfering RNA (siRNA-AQP3) on antrum formation and follicular growth in vitro. Various combinations of Lipofectamine® volumes (0.5, 0.75 or 1.0 µl), fluorescent oligonucleotide (BLOCK-iT ™) concentrations (3.18, 27.12 or 36.16 nM) and exposure times (12, 14, 16, 18 or 20 h) were tested. The BLOCK-iT™ was replaced by siRNA-AQP3 in the transfection complex. Ovine secondary follicles were isolated and cultured in vitro for 6 days using standard protocols. Follicles were transfected on day 0 or 3 or on both days (0 and 3) and then cultured for an additional 3 or 6 days. As revealed by the fluorescence signal, the Lipofectamine®/BLOCK-iT™ complex (0.75 µl + 27.12 nM by 12 h of incubation) crossed the basement membrane and granulosa cell and reached the oocytes. In general, the rate of intact follicles was higher and the rate of antrum formation was lower in transfected follicles compared with control follicles. In conclusion, ovine secondary follicles can be successfully transfected during in vitro culture, and siRNA-mediated attenuation of AQP3 gene reduced antrum formation of secondary follicles.

Sheep Isolated Secondary Follicles Are Able to Produce Metaphase II Oocytes After Vitrification and Long-Term In Vitro Growth

The vitrification of preantral follicles followed by in vitro growth (IVG) could be valuable to produce fertilizable oocytes. However, the meiotic resumption rates of oocytes cultured from vitrified secondary follicles (SF) have been reported as suboptimal. This study aimed to verify two base media (alpha modification of minimum essential medium, α-MEM, and tissue culture medium 199, TCM199) on vitrified SF regarding different requirements during IVG. Sheep ovarian fragments were divided in six groups: (1) Fresh groups (Control α-MEM and TCM199): SF without vitrification; (2) Follicle-Vitrified (Follicle-Vit α-MEM and TCM199): SF vitrified after isolation; and (3) Tissue-Vitrified (Tissue-Vit α-MEM and TCM199): SF vitrified enclosed in ovarian fragments and, subsequently, isolated. The isolated SF were submitted to IVG for 18 days. Thereafter, the recovered cumulus-oocyte complexes (COCs) underwent in vitro maturation (IVM) and evaluation of chromatin configuration. Follicular granulosa cells were analyzed for their gene expression of Bax, Bcl2, and Connexins (CX) 37 and 43. COCs from in vivo antral follicles were used as in vivo control. Data were analyzed by analysis of variance, Tukey, and chi-square tests. Differences were considered significant if p-value is <0.05. Follicle-Vit groups had higher (p < 0.05) percentage of antrum formation compared with Tissue-Vit groups. Vitrification did not affect (p > 0.05) oocyte diameter postmaturation. Oocytes from Follicle-Vit in α-MEM reached metaphase II stage after IVM. Gene expression for CX37, CX43, and Bax was lower in Tissue-Vit groups. For Bcl2, the gene expression was the opposite. In conclusion, during IVG for 18 days, maximal oocyte meiotic resumption was not negatively impacted by vitrification and was greatest for isolated SF using α-MEM as a medium.

Unilaminar follicular cells transiently express galectin-3 during ovarian folliculogenesis in pigs

The localization of galectin-3, a β-galactoside-binding animal lectin, was immunohistochemically studied in the ovaries of pigs to determine its expression in ovarian folliculogenesis. Various stages of ovarian follicles were identified in the ovaries of adult pigs. Galectin-3 was immunostained in the squamous follicular cells surrounding oocytes in primordial follicles and in the unilaminar granulosa cells of primary follicles, but not in oocytes of multilaminar follicles (including primary, secondary, and tertiary Graafian follicles). As in adult ovaries, galectin-3 immunoreactivity was prominent in the unilaminar follicles in neonatal ovaries. Galectin-3 was also immunolocalized in the luteal cells in the corpus luteum and granulosa cells of atretic follicles as well as in interstitial macrophages in porcine ovaries. Collectively, these results suggest that galectin-3 is transiently expressed in follicular cells in the unilaminar ovarian follicles (primordial and primary) but not in multilaminar ovarian follicles (primary to tertiary), implying that galectin-3 is embryologically involved in ovum generation.

Modulation of aquaporins 3 and 9 after exposure of ovine ovarian tissue to cryoprotectants followed by in vitro culture

Our aim has been to evaluate the effect of cryoprotective agents (CPAs) on the exposure, vitrification (VIT), and in vitro culture (IVC) of ovarian tissue with regard to the expression and immunolocalization of aquaporins (AQPs) 3 and 9 in ovine preantral follicles. Tissues were treated as follows: Experiment I: (1) control (without exposure to CPAs), (2) e-EG (exposure to ethylene glycol), (3) er-EG (exposure to and removal of EG), (4) e-DMSO (exposure to dimethyl sulfoxide), (5) er-DMSO (exposure to and removal of DMSO), (6) e-EG+DMSO (exposure to EG+DMSO), (7) er-EG+DMSO (exposure to and removal of EG+DMSO); Experiment II: (1) control, (2) VIT, (3) IVC, (4) VIT-IVC. In Experiment I, following er-EG or er-DMSO, tissue showed the down-regulation (P < 0.05) of AQP3 mRNA. The mRNA transcript levels were reduced (P < 0.05) for AQP9 in tissue following er-EG+DMSO. Immunolocalization was positive for both proteins (AQP3 and AQP9) on ovine preantral follicles following all treatments, except in the e-EG+DMSO group. In Experiment II, the mRNA levels of AQP3 and AQP9 following VIT treatment were similar (P > 0.05) to that of the control group. Nevertheless, VIT-IVC treatment led to the down-regulation of mRNA of AQP3 and AQP9. Thus, AQP3 and AQP9 act in a mutually dependent way, maintaining the cell homeostasis that is essential for the ovary cryopreservation process. Furthermore, the changes in the expression profiles of mRNA and protein after culture are a strong indicator that in vitro conditions have to be strictly controlled to ensure follicle viability and functionality.

Schistosome syntenin partially protects vaccinated mice against Schistosoma mansoni infection

Background

Schistosomiasis is a neglected tropical disease caused by several species of trematode of the genus Schistosoma. The disease affects more than 200 million people in the world and causes up to 280,000 deaths per year, besides having high morbidity due to chronic illness that damages internal organs. Current schistosomiasis control strategies are mainly based on chemotherapy, but many researchers believe that the best long-term strategy to control disease is a combination of drug treatment and immunization with an anti-schistosome vaccine. Among the most promising molecules as vaccine candidates are the proteins present in the tegument and digestive tract of the parasite.

Methodology/Principal Findings

In this study, we describe for the first time Schistosoma mansoni syntenin (SmSynt) and we evaluate its potential as a recombinant vaccine. We demonstrate by real-time PCR that syntenin is mainly expressed in intravascular life stages (schistosomula and adult worms) of the parasite life cycle and, by confocal microscopy, we localize it in digestive epithelia in adult worms and schistosomula. Administration of siRNAs targeting SmSynt leads to the knock-down of syntenin gene and protein levels, but this has no demonstrable impact on parasite morphology or viability, suggesting that high SmSynt gene expression is not essential for the parasites in vitro. Mice immunization with rSmSynt, formulated with Freund's adjuvant, induces a Th1-type response, as suggested by the production of IFN-γ and TNF-α by rSmSynt-stimulated cultured splenocytes. The protective effect conferred by vaccination with rSmSynt was demonstrated by 30–37% reduction of worm burden, 38–43% reduction in the number, and 35–37% reduction in the area, of liver granulomas.

Conclusions/Significance

Our report is the first characterization of syntenin in Schistosoma mansoni and our data suggest that this protein is a potential candidate for the development of a multi-antigen vaccine to control schistosomiasis.

Schistosomiasis affects more than 200 million people worldwide and causes up to 280,000 deaths per year. In terms of global mortality and morbidity, this disease is the most important human helminth infection. Current control strategies are based on chemotherapy, but recurrent re-infection of people living in endemic areas makes many researchers, and also the World Health Organization, search for an effective vaccine to provide protection against schistosomiasis. Substantial efforts have been committed to the characterization of new antigens for an anti-schistosome vaccine and, in order to find new targets for vaccine and/or drug development, we searched transcriptomics and proteomics of Schistosoma mansoni and identified the protein syntenin (SmSynt) for analysis. In this study, we characterize SmSynt and evaluate its potential as a vaccine candidate to protect mice against S. mansoni infection. We demonstrate that SmSynt is expressed in schistosomula and adult worms, the intravascular stages of S. mansoni and it is located in the intestinal tract of the worms, an important host/parasite interface. Furthermore, vaccination of mice with rSmSynt confers partial protection against S. mansoni challenge infection and ameliorates parasite-induced liver pathology. Our data suggest that SmSynt is a potential candidate in the development of a vaccine against schistosomiasis.