Sander van Den Driesche

Epigenetic reprogramming of fetal germ cells involves the genome-wide erasure and subsequent re-establishment of DNA methylation. Mouse studies indicate that DNA demethylation may be initiated at embryonic day (e) 8 and completed between e11.5 and e12.5. In the male germline, DNA remethylation begins around e15 and continues for the remainder of gestation whilst this process occurs postnatally in female germ cells. Although 5-methylcytosine (5mC) dynamics have been extensively characterised, a role for the more recently described DNA modifications (5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC)) remains unclear. Moreover, the extent to which the developmental dynamics of 5mC reprogramming is conserved across species remains largely undetermined. Here, we sought to describe this process during late gestation in the male rat. Using immunofluorescence, we demonstrate that 5mC is re-established between e18.5 and e21.5 in the rat, subsequent to loss ...

Vascular endothelial growth factor (VEGF)-dependent angiogenesis is crucial for follicular growth, and corpus luteum formation and function, in the primate ovary. In the ovary VEGF can be hormonally regulated, but in other systems, the main regulator of VEGF expression is hypoxia. We hypothesized that hypoxia was involved in the regulation of angiogenesis in the cycling ovary. We therefore used immunohistochemistry to localize hypoxia-inducible factor (HIF)-1alpha in the marmoset ovary across the ovarian cycle. We also investigated the effect of VEGF inhibition, using VEGF Trap (aflibercept), on HIF-1alpha localization during the follicular and luteal phases of the cycle. Finally, we studied the effect of chorionic gonadotropin stimulation of the corpus luteum during early pregnancy. Nuclear HIF-1alpha staining was largely absent from normally growing preantral and antral follicles. However, there was marked up-regulation of nuclear HIF-1alpha in the granulosa cells at ovulation tha...

Vascular endothelial growth factor (VEGF)-dependent angio- genesis is crucial for follicular growth, and corpus luteum formation and function, in the primate ovary. In the ovary VEGF can be hormonally regulated, but in other systems, the main regulator of VEGF expression is hypoxia. We hypothe- sized that hypoxia was involved in the regulation of angio- genesis in the cycling ovary. We

The luteinizing hormone (LH) receptor is fundamental for the regulation of the corpus luteum (CL) in women and non-human primates. Its ligands, LH and human chorionic gonadotropin (hCG), have key roles in the regulation of tissue and vascular remodeling associated with luteal formation and regression. However this remodeling involves the regulation of cells that do not express LH receptors including

Phthalate exposure induces germ cell effects in the rat fetal testis. Whilst experimental models have shown that the human fetal testis is insensitive to the steroidogenic effects of phthalates, the effects on germ cells are less explored. To identify the effects of phthalate exposure on human fetal germ cells in a dynamic model and to establish if the rat is an appropriate model for investigating such effects. Immunohistochemistry, immunofluorescence and quantitative real-time PCR for Sertoli and germ cell markers on vehicle/di(n-butyl) phthalate (DBP)-exposed rat testes and human fetal testis xenografts. This included analysis of germ cell differentiation markers, proliferation markers and cell adhesion proteins. In both rat and human fetal testes, DBP exposure induced similar germ cell effects, namely germ cell loss (predominantly undifferentiated), induction of multinucleated gonocytes (MNGs) and aggregation of differentiated germ cells, although the latter occurred rarely in th...

Reproductive disorders that are common/increasing in prevalence in human males may arise because of deficient androgen production/action during a fetal 'masculinization programming window'. We identify a potentially important role for Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) in Leydig cell (LC) steroidogenesis that may partly explain this. In rats, fetal LC size and intratesticular testosterone (ITT) increased ~3-fold between e15.5-e21.5 which associated with a progressive decrease in the percentage of LC expressing COUP-TFII. Exposure of fetuses to dibutyl phthalate (DBP), which induces masculinization disorders, dose-dependently prevented the age-related decrease in LC COUP-TFII expression and the normal increases in LC size and ITT. We show that nuclear COUP-TFII expression in fetal rat LC relates inversely to LC expression of steroidogenic factor-1 (SF-1)-dependent genes (StAR, Cyp11a1, Cyp17a1) with overlapping binding sites for SF-1 and C...

Ectopic pregnancy is common but remains difficult to diagnose accurately. There is no serum test to differentiate ectopic from intrauterine gestation. Our objective was to investigate differential gene expression in decidualized endometrium of ectopic pregnancy. Tissue and serum analysis informed by microarray study was performed. The study was performed at a large United Kingdom teaching hospital. Women undergoing surgical termination of pregnancy (n = 8), evacuation of uterus for miscarriage (n = 6), and surgery for tubal ectopic pregnancy (n = 11) were included in the study. Endometrium was collected from normally cycling women undergoing hysterectomy. Decidualized endometrium was subjected to microarray analysis, morphological assessment, and immunohistochemistry. Endometrial stromal fibroblasts were cultured in the presence of decidualizing stimuli. Differential expression of potentially secreted molecules was calculated. Inhibin/activin beta-B expression was lower in decidualized endometrium from ectopic pregnancies when compared with that of ongoing pregnancies (P < 0.01) or miscarriages (P < 0.01). The localization of the beta-B subunit was more marked in decidualized than nondecidualized stroma. Decidualization of stromal fibroblasts in vitro was associated with increased beta-B expression (P < 0.05). Endometrial stroma of ectopic pregnancies was less decidualized morphologically (P < 0.05), with lower prolactin (P < 0.01) and IGF binding protein-1 (P < 0.005) expression. Serum activin B was lower in ectopic pregnancies (P < 0.005) than in intrauterine pregnancies, whereas there was no difference in progesterone concentrations. Despite similar concentrations of progesterone, the endometrium of ectopic pregnancies is less decidualized than intrauterine pregnancies. Expression of the beta-B subunit is related to decidualization and can be detected in the circulation as activin B. Serum activin B concentrations are lower in ectopic pregnancy.