Paternal effects on early embryogenesis

Historically, less attention has been paid to paternal effects on early embryogenesis than maternal effects. However, it is now apparent that certain male factor infertility phenotypes are associated with increased DNA fragmentation and/or chromosome aneuploidies that may compromise early embryonic development. In addition, there is a growing body of evidence that the fertilizing sperm has more function than just carrying an intact, haploid genome. The paternally inherited centrosome is essential for normal fertilization, and the success of higher order chromatin packaging may impact embryogenesis. Epigenetic modifications of sperm chromatin may contribute to the reprogramming of the genome, and sperm delivered mRNA has also been hythesized to be necessary for embryogenesis. There is less information about the epigenetic factors affecting embryogenesis than genetic factors, but the epigenetics of gamete and early embryogenesis is a rapidly advancing field

Letrozole reduces estrogen and gonadotropin exposure in women with breast cancer undergoing ovarian stimulation before chemotherapy

PubMed: 16882752Context: Women with breast cancer are not typically offered embryo or oocyte cryopreservation to preserve their fertility before chemotherapy because of the potential risks associated with high estrogen levels arising from ovarian stimulation. Objective: We aimed to determine whether the combination of an aromatase inhibitor with gonadotropin treatment in breast cancer patients produces comparable results to standard in vitro fertilization (IVF), without a significant increase in estradiol levels and delay in the initiation of chemotherapy. Patients and Methods: Stages I-IIIA breast cancer patients (n = 47) received 5 mg/d letrozole and 150-300 IU FSH to cryopreserve embryos or oocytes. Age-matched retrospective controls (n = 56) were selected from women who underwent IVF for tubal disease. Results: Whereas letrozole and FSH stimulation resulted in significantly lower peak estradiol levels (mean ± SD 483.4 ± 278.9 vs. 1464.6 ± 644.9 pg/ml; P < 0.001) and 44% reduction in gonadotropin requirement, compared with controls, the length of stimulation, number of embryos obtained, and fertilization rates were similar. The human chorionic gonadotropin administration criteria had to be adjusted to 20 mm after letrozole stimulation, compared with 17-18 mm in the controls. The mean delay from surgery to cryopreservation was 38.6 d, with 81% of all patients completing their IVF cycles within 8 wk of surgery. Conclusion: Ovarian stimulation with letrozole and FSH appears to be a cost-effective alternative for fertility preservation in breast cancer patients with reduced estrogen exposure, compared with standard IVF. If patients are referred promptly, they may undergo embryo or oocyte cryopreservation without a delay in chemotherapy. Copyright © 2006 by The Endocrine Society

Elucidating Decorin’s role in the preovulatory follicle

Abstract Background DCN (decorin) is a proteoglycan known to be involved in regulating cell proliferation, collagen fibril organization and migration. In our global transcriptome RNA-sequencing approach to systematically identify new ovulation-associated genes, DCN was identified as one of the highly regulated genes. We therefore hypothesize that DCN may have a role in ovulatory processes such as cell migration and proliferation. Aim To characterize the expression, regulation and function of the proteoglycan DCN in the human ovarian follicles during the preovulatory period. Methods The in-vivo expression of DCN mRNA in mural (MGCs) and cumulus (CGCs) granulosa cells was characterized using quantitative RT-PCR and western blot. A signaling study was performed by treating human MGCs cultures with gonadotropins and different stimulators and inhibitors to determine their effect on DCN expression by qRT- PCR and elucidate the pathways regulating these proteins. In a functional study, KGN granulosa cell line was used to study cell migration with a scratch assay. Results DCN mRNA expression was significantly higher in MGCs compared to CGCs. DCN mRNA was significantly higher in CGCs surrounding mature metaphase II (MII) oocytes compared to CGCs of germinal vesicle (GV) and metaphase I (MI) oocytes. hCG significantly increased DCN mRNA and protein expression levels in cultured MGCs. Using signal transduction activators and inhibitors, we demonstrated that DCN induction by LH/hCG is carried out via PKA, PKC, ERK/MEK, and PI3K pathways. We showed that DCN expression is also induced in high-density cell cultures, in a dose-dependent pattern. In addition, progesterone induced a significant increase in DCN secretion to the media. MGCs from follicles of endometriosis patients exhibited reduced (about 20% of) mRNA transcriptions levels compared to MGCs follicles of control patients. More significantly, we found that DCN has an inhibiting effect on KGN cell migration. Conclusions Our study indicates that DCN is a unique ovulatory gene. Our findings support the hypothesis that DCN plays an important new role during the preovulatory period and ovulation, and stress its involvement in endometriosis infertility. A better understanding of DCN role in ovulation and endometriosis may provide treatment for some types of infertility

Characterization of the miRNA regulators of the human ovulatory cascade

Abstract Ovarian follicular development and ovulation are complex and tightly regulated processes that involve regulation by microRNAs (miRNAs). We previously identified differentially expressed mRNAs between human cumulus granulosa cells (CGCs) from immature early antral follicles (germinal vesicle - GV) and mature preovulatory follicles (metaphase II - M2). In this study, we performed an integrated analysis of the transcriptome and miRNome in CGCs obtained from the GV cumulus-oocyte complex (COC) obtained from IVM and M2 COC obtained from IVF. A total of 43 differentially expressed miRNAs were identified. Using Ingenuity IPA analysis, we identified 7288 potential miRNA-regulated target genes. Two hundred thirty-four of these target genes were also found in our previously generated ovulatory gene library while exhibiting anti-correlated expression to the identified miRNAs. IPA pathway analysis suggested that miR-21 and FOXM1 cooperatively inhibit CDC25A, TOP2A and PRC1. We identified a mechanism for the temporary inhibition of VEGF during ovulation by TGFB1, miR-16-5p and miR-34a-5p. The linkage bioinformatics analysis between the libraries of the coding genes from our preliminary study with the newly generated library of regulatory miRNAs provides us a comprehensive, integrated overview of the miRNA-mRNA co-regulatory networks that may play a key role in controlling post-transcriptomic regulation of the ovulatory process