Quantification of insulin-like growth factor I receptors on granulosa cells with flow cytometry after follicular stimulation

Stimulation of the JAK/STAT pathway by LIF and OSM in the human granulosa cell line COV434

The development of the follicle and competent oocyte is highly coordinated, requiring interplay among several systems. These implicate endocrine, immune, and metabolic signals, intrafollicular paracrine factors from theca, mural, and cumulus granulosa cells, and the oocyte itself. Granulosa cells play a key role in their interaction. COV434 is one of the few human granulosa cell lines that can be used as an in vitro model for ovarian research. We aimed to evaluate the possible activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway by IL-6-type cytokines leukemia inhibitory factor (LIF) and oncostatin M (OSM) in COV434 cells. Expression of GP130 (glycoprotein 130), STAT3 (signal transducer and activators of transcription 3), PIAS3 (protein inhibitor of activated STAT 3), and SOCS3 (suppressor of cytokine signaling 3) genes after stimulation with LIF or OSM was assessed using RT-qPCR (real-time PCR). GP130 transcripts were significantly upregulated after incubation with LIF or OSM for 24h. Expression of the STAT3 gene was stimulated only after incubation with LIF, but not OSM. SOCS3 showed significant upregulation for all time periods and the levels of PIAS3 were initially down- and after 24h upregulated. Furthermore, the major signaling components of the JAK/STAT pathway, GP130 and STAT3, and the kinase activation patterns of STAT3, were examined at protein level. We found constitutive protein expression for GP130, STAT3, pSTAT3(ser727) and upregulation of pSTAT3(tyr705) by LIF and OSM. Our results demonstrate the activation of the JAK/STAT pathway by LIF and OSM in human granulosa cells.

Computational modelling of bovine ovarian follicle development

Background

The development of ovarian follicles hinges on the timely exposure to the appropriate combination of hormones. Follicle stimulating hormone (FSH) and luteinizing hormone (LH) are both produced in the pituitary gland and are transported via the blood circulation to the thecal layer surrounding the follicle. From there both hormones are transported into the follicle by diffusion. FSH-receptors are expressed mainly in the granulosa while LH-receptors are expressed in a gradient with highest expression in the theca. How this spatial organization is achieved is not known. Equally it is not understood whether LH and FSH trigger distinct signalling programs or whether the distinct spatial localization of their G-protein coupled receptors is sufficient to convey their distinct biological function.

Results

We have developed a data-based computational model of the spatio-temporal signalling processes within the follicle and (i) predict that FSH and LH form a gradient inside the follicle, (ii) show that the spatial distribution of FSH- and LH-receptors can arise from the well known regulatory interactions, and (iii) find that the differential activity of FSH and LH may well result from the distinct spatial localisation of their receptors, even when both receptors respond with the same intracellular signalling cascade to their ligand.

Conclusion

The model integrates the large amount of published data into a consistent framework that can now be used to better understand how observed defects translate into failed follicle maturation.

FSH stimulates the expression of the ADAMTS-16 protease in mature human ovarian follicles

We report the characterization of full-length human ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs)-16, a novel member of the disintegrin and metalloproteinase with thrombospondin motifs (hence ADAMTS) family. ADAMTS-16 is highly expressed both in the kidney and in the ovary, where it is predominantly expressed in the parietal granulosa cells of pre-ovulatory follicles but only slightly expressed in cells of the cumulus oophorus. In fully differentiated luteinizing granulosa cells, follicle-stimulating hormone and forskolin induces expression of ADAMTS-16, suggesting that it is regulated via the cAMP pathway. Luteinizing hormone had a minor effect on the expression of ADAMTS-16. ADAMTS-16 is capable of cleaving alpha2-macroglobulin (MG), a common substrate for proteases, which is present at high concentrations in the follicular fluid of ovarian follicles. These studies provide the first evidence that ADAMTS-16 is an active protease and suggest a physiological role of ADAMTS-16 in ovarian follicles, at least during the pre-ovulatory phase.

Comparisons of follicular levels of sex steroids, gonadotropins and insulin like growth factor-1 (IGF-1) and epidermal growth factor (EGF) in poor responder and normoresponder patients undergoing ovarian stimulation with GnRH antagonist

OBJECTIVE

To determine the serum and intrafollicular concentrations of sex steroids, epidermal growth factor (EGF) and insulin like growth factor-1 (IGF-1) in women demonstrating poor response to ovarian stimulation with gonadotropins and GnRH antagonists, and to compare the results with age-matched women displaying normal ovarian response.

STUDY DESIGN

This is a prospective cross-sectional study conducted in a private IVF center. Forty-eight age-matched women producing 5 or fewer oocytes (poor responders) or 10 or more oocytes (normoresponders) at the end of controlled ovarian stimulation for assisted conception participated in the experiment. Gonadotropins and GnRH antagonists were used for ovarian stimulation, while ICSI was employed for assisted fertilization. Serum and follicular concentrations of FSH, LH and sex steroids (estradiol, progesterone and testosterone), and follicular concentrations of EGF and IGF-1 were assayed in both groups.

RESULTS

Serum and follicular levels of E(2) and progesterone were significantly lower in the poor responder group compared to the normoresponder group. Follicular level of testosterone was also lower in poor responders, but not to a level of statistical significance. The serum FSH level was higher in the poor responder group, but follicular levels of gonadotropins did not differ between the two groups. The follicular level of IGF-1 was significantly lower in poor responders. In contrast, the EGF concentration did not differ between the two groups.

CONCLUSIONS

Decreased levels of sex steroids in poor responder patients undergoing COH with GnRH antagonist, suggests that reduced IGF-1 expression acts as a modulator of impaired ovarian steroidogenesis.

Purification of granulosa cells from human ovarian follicular fluid using granulosa cell aggregates

Human follicular fluid can provide a source of human granulosa cells for scientific study. However, removing potentially contaminating cells, such as white and red blood cells, is important for molecular and in vitro studies. We have developed a purification technique for human granulosa cells based on the selection of cellular aggregates. Human granulosa cells from 21 IVF patients were collected. A 50% Percoll gradient was used to remove red blood cells, and granulosa cell aggregates were collected, washed and processed for histology, electron microscopy, flow cytometry analysis, cell culture and RNA extraction. Granulosa cell aggregates were found to be homogeneous and free of white blood cells after histological and electron microscopic analysis. White blood cell contamination, measured by flow cytometry, was found to be between 2 and 4%. Polymerase chain reaction analysis revealed expression of known human granulosa cell genes and a white blood cell marker. Human granulosa cells grown in vitro showed flattened fibroblast-like morphology with lipid droplets consistent with previous reports. Cultured cells expressed the FSH receptor. Selection of human granulosa cell aggregates following centrifugation through a Percoll gradient provides an efficient method of selecting granulosa cells, suitable for both molecular and in vitro studies.

A confocal microscopy analysis of the spindle and chromosome configurations of human oocytes cryopreserved at the germinal vesicle and metaphase II stage

BACKGROUND

Routine oocyte cryopreservation remains an elusive technique in the wide range of assisted reproductive technologies available. This study examines the effect of a cryopreservation protocol on the spindle and chromosome configurations of human oocytes cryopreserved at the germinal vesicle (GV) and metaphase II (MII) stage.

METHODS

GV oocytes were randomly assigned to one of three groups: (i) control oocytes matured in vitro to MII stage (n = 156); (ii) oocytes cryopreserved at the GV stage and then matured in vitro (n = 90); (iii) oocytes cryopreserved at the MII stage (n = 147). Following cryopreservation and in-vitro maturation, immunostaining of tubulin and chromatin was performed, before visualization using confocal microscopy.

RESULTS

A statistically significant increase was observed in the survival rate in group 2 (73.3%, 66/90) compared to group 3 (55.7%, 82/147) (P < 0.007). Exposure of oocytes to the cryoprotective solutions without freezing had no effect on the structure of their second meiotic spindle. However, statistically significant differences were observed on both spindle and chromosome configurations of oocytes from group 2 (5.2 and 5.2% respectively) and group 3 (16.2 and 18.8% respectively) compared with group 1 oocytes (71.6 and 82.0% respectively) (P < 0.001 in all cases).

CONCLUSIONS

The protocol followed results in high rates of survival and potential for in-vitro maturation, but has a deleterious effect on the organization of the meiotic spindle of human oocytes cryopreserved at both the GV and MII stages.

Expression of growth-factor receptors in normal and regenerating human periodontal cells

Growth factors are biologically active mediators that bind to specific receptors on target cells and regulate genes involved in cell growth, wound healing and regeneration. The expression of these receptors is thus of fundamental importance for the response of the cells to the factors. The aim here was to examine, using immunohistochemistry and flow cytometry, the expression of growth factor receptors in normal gingiva, periodontal ligament and in cells derived from these tissues, and also in regenerated tissues following guided tissue regeneration (GTR). By immunocytochemistry platelet-derived growth factor receptor-alpha (PDGF-Ralpha) was not detected in any of the tissues, whereas the PDGF-Rbeta and transforming growth factor-beta receptor types I and II (TGF-beta RI, RII) appeared to be upregulated in regenerated tissues compared with gingival and periodontal ligament tissues. Epidermal growth factor receptor (EGF-R) was also notably elevated in the regenerated tissue and was strongly expressed in the gingival epithelium but not in the periodontal ligament. Neither were fibroblast growth factor receptor-I (FGF-RI) or insulin-like growth factor receptor (IGF-R) detected in the periodontal ligament, nor in the gingiva, but they sometimes stained weakly in the regenerated tissues. Flow cytometry (FCM) showed that all the cells derived from the normal gingiva and the periodontal ligament expressed the PDGF-Rbeta, whereas the TGF-beta RI and RII, FGF-RI and IGF-R were detected in only a proportion of the total cells. In contrast, none of the cells expressed the PDGF-Ralpha or the EGF-R. These observations show that the growth factor receptors are differentially expressed by the periodontal tissues and cells and suggest that the corresponding factors may also be differentially involved in periodontal wound healing and regeneration.

Successful pregnancy following replacement of embryos previously refrozen at blastocyst stage: case report

We present the first reported clinical pregnancy following transfer of embryos that had been subjected to two freeze-thaw cycles: the first at day 3 after insemination, and the second after culturing to the blastocyst stage. A 25-year-old woman undergoing IVF treatment for male factor infertility opted for intracytoplasmic sperm injection (ICSI). ICSI treatment resulted in the successful production of 19 early cleavage embryos, all of which were frozen. After thawing, the embryos were cultured to the blastocyst stage. Thereafter, the blastocysts were refrozen and again thawed prior to embryo transfer. Embryos surviving a day 3 freeze-thaw cycle developed to the blastocyst stage and survived the second freeze-thaw cycle. Successful clinical pregnancy resulted following two sequential freeze-thaw cycles. This finding shows that it is possible to refreeze supernumerary blastocysts for subsequent transfer.