Cumulus oophorus extracellular matrix: its construction and regulation

Unique hyaluronan structure of expanded oocyte-cumulus extracellular matrix in ovarian follicles

In preovulatory follicles, after the endogenous gonadotropin surge, the oocyte-cumulus complexes (OCCs) produce hyaluronan (HA) in a process called "cumulus expansion". During this process, the heavy chains (HCs) of the serum-derived inter-alpha-trypsin inhibitor (IαI) family bind covalently to synthesized HA and form a unique structure of the expanded cumulus HA-rich extracellular matrix. Understanding the biochemical mechanism of the covalent linkage between HA and the HCs of the IαI family is one of the most significant discoveries in reproductive biology, since it explains basis of the cumulus expansion process running in parallel with the oocyte maturation, both essential for ovulation. Two recent studies have supported the above-mentioned findings: in the first, seven components of the extracellular matrix were detected by proteomic, evolutionary, and experimental analyses, and in the second, the essential role of serum in the process of cumulus expansion in vitro was confirmed. We have previously demonstrated the formation of unique structure of the covalent linkage of HA to HCs of IαI in the expanded gonadotropin-stimulated OCC, as well as interactions with several proteins produced by the cumulus cells: tumor necrosis factor-alpha-induced protein 6, pentraxin 3, and versican. Importantly, deletion of these genes in the mice produces female infertility due to defects in the oocyte-cumulus structure.

IZUMO1 Receptor Localization during Hyaluronic Acid Selection in Human Spermatozoa

IZUMO1 is an acrosome transmembrane protein implicated in the adhesion and fusion of gametes. This study aims to describe the distribution of IZUMO1 in human sperm under different physiological conditions: before capacitation (NCS), at one-hour capacitation (CS1), after a hyaluronic acid (HA) selection test (mature, MS1 and immature, IS1), and induced acrosome reaction from one-hour-capacitated sperm (ARS1). The data obtained in NCS, CS1, and MS1 significantly highlight dotted fluorescence in the acrosomal region (P1) as the major staining pattern (~70%). Moreover, we describe a new distribution pattern (P2) with a dotted acrosomal region and a labelled equatorial region that significantly increases in HA-bound spermatozoa, suggesting the onset of the migration of IZUMO1. In contrast, unbound spermatozoa presented an increase in P3 (equatorial region labelled) and P4 (not labelled). Finally, costaining to observe IZUMO1 distribution and acrosome status was performed in ARS1. Interestingly, we reported a variety of combinations between the IZUMO1 staining patterns and the acrosomal stages. In conclusion, these data show as a novelty the diffusion of the IZUMO1 protein during different physiological conditions that could contribute to the improvement in sperm selection techniques.

Microfluidic devices employing chemo- and thermotaxis for sperm selection can improve sperm parameters and function in patients with high DNA fragmentation

Conventional sperm processing uses centrifugation has a negative effect on sperm parameters and DNA integrity. We designed and fabricated a novel microfluid device based on chemotaxis and thermotaxis, and compared it with the swim-up method. Twenty normal samples with high DNA fragmentation were included. Each sample was divided into four groups: Group 1, control, Group 2: sperm selection by thermotaxis, Group 3: sperm selection by chemotaxis, and Group 4: sperm selection with thermotaxis and chemotaxis. We used cumulus cells in a microfluid device to create chemotaxis, and, two warm stages to form a temperature gradient for thermotaxis. The spermatozoa were assessed based on the concentration, motility, and fine morphology using Motile Sperm Organelle Morphology Examination, mitochondrial membrane potential (MMP), acrosome reaction (AR), and sperm DNA fragmentation. Concentration (22.40 ± 5.39 vs. 66.50 ± 19.21; p < 0.001) and DNA fragmentation (12.30 ± 3.96% vs. 17.95 ± 2.89%; p < 0.001) after selection in the chemotaxis and thermotaxis microfluid device were significantly lower than control group. The progressive motility (93.75 ± 4.39% vs. 75.55 ± 5.86%, p < 0.001), normal morphology (15.45 ± 2.50% vs. 10.35 ± 3.36, p < 0.001), MMP (97.65 ± 1.81% vs. 94 ± 3.89%, p = 0.02), and AR status (79.20 ± 5.28% vs. 31.20 ± 5.24%, p < 0.001) in the chemotaxis and thermotaxis microfluid device were significantly increased compared to control group. According to these findings, spermatozoa that have penetrated the cumulus oophorus have better morphology and motility, as well as acrosome reactivity and DNA integrity.

Sperm Adhesion Molecule 1 (SPAM1) Distribution in Selected Human Sperm by Hyaluronic Acid Test

The failures of binding to the oocyte zona pellucida are commonly attributed to defects in the sperm recognition, adhesion, and fusion molecules. SPAM1 (sperm adhesion molecule 1) is a hyaluronidase implicated in the dispersion of the cumulus-oocyte matrix. Therefore, the aim of this study was to characterize the SPAM1 distribution in the different physiological conditions of human sperm. Specifically, we evaluated the location of the SPAM1 protein in human sperm before capacitation, at one and four hours of capacitation and after hyaluronic acid (HA) selection test by fluorescence microscopy. Sperm bound to HA were considered mature and those that crossed it immature. Our results detected three SPAM1 fluorescent patterns: label throughout the head (P1), equatorial segment with acrosomal faith label (P2), and postacrosomal label (P3). The data obtained after recovering the mature sperm by the HA selection significantly (p < 0.05) highlighted the P1 in both capacitation times, being 79.74 and 81.48% after one hour and four hours, respectively. Thus, the HA test identified that human sperm require the presence of SPAM1 throughout the sperm head (P1) to properly contact the cumulus-oocyte matrix. Overall, our results provide novel insights into the physiological basis of sperm capacitation and could contribute to the improvement of selection techniques.

Inter-Alpha-Trypsin Inhibitor Heavy Chain 4 Plays an Important Role in the Development and Reproduction of Nilaparvata lugens

Simple Summary

The brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae), is a destructive insect pest of rice. It causes reductions in rice yield and great economic losses. In this study, we used RNAi to explore the function of the inter-alpha-trypsin inhibitor heavy chain 4 (ITIH4) gene in the development and reproduction of the brown planthopper. Our results revealed that ITIH4 influences the survival, ovarian development, egg production, and egg hatching of this insect, indicating that ITIH4 plays important roles in development and reproduction. Considering the importance of ITIH4 in the brown planthopper, it may be a potential target for pest management.

Abstract

The brown planthopper, Nilaparvata lugens, is a difficult-to-control insect pest affecting rice yields in Asia. As a structural component of the inter-alpha-trypsin inhibitor (ITI), the inter-alpha-trypsin inhibitor heavy chain (ITIH) has been reported to be involved in various inflammatory or malignant disorders, ovarian development, and ovulation. To reveal the function of ITIH4 in N. lugens, the gene encoding N. lugens ITIH4 (NlITIH4) was cloned and characterized. NlITIH4 contains a signal peptide, a vault protein inter-alpha-trypsin domain, and a von Willebrand factor type A domain. qPCR analysis showed that NlITIH4 was expressed at all developmental stages and in all tissues (fat body, ovary, and gut), with the highest expression in the fat body. Double stranded NlITIH4 (dsNlITIH4) injection clearly led to an RNAi-mediated inhibition of the expression of NlITIH4 and resulted in reduced survival, delayed ovarian development, and reduced egg production and egg hatching. These results indicate that NlITIH4 plays an important role in the development and reproduction of N. lugens.

Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment

This study examined the status of oxidative stress in 599 couples undertaking in vitro fertilization (IVF) treatment and its association with reproductive hormones, smoking, and outcomes. Oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide (H₂O₂), catalase (CAT), and total antioxidant capacity (TAC) were determined in follicular fluid and seminal plasma. Tail moment (TM) was used to evaluate DNA damage in the sperm and granulosa cells. Reproductive hormones in serum and cotinine (COT) in urine, follicular fluid, and seminal plasma samples were determined. Separate multivariate linear regression was used to assess associations between levels of each oxidative stress biomarker and each hormone and smoking parameter (modeled as natural log-transformed). The findings indicate that some oxidative stress and DNA damage biomarkers played a role in disrupting certain reproductive hormones in women and their male partners either by overproducing reactive oxygen species or reducing antioxidant defense capacity. Although women were nonsmokers, COT levels > 50 and 10 µg/L in urine and follicular were observed in 5.7 and 1.7%, respectively. Levels of follicular fluid COT were positively associated with H₂O₂ and TM. We used log-binomial multivariate regression to estimate relative risks for the association between oxidative stress/DNA damage and IVF binary outcomes (fertilization rate > 50%, biochemical pregnancy, clinical pregnancy, and live birth). An increase in the CAT levels of follicular fluid was associated with a 48 and 41% decrease in the risk of poor fertilization rate (≤50%) and unsuccessful live birth, respectively. After the models were adjusted for hormonal factors, the associations remained the same, except that the elevated TAC in follicular fluid became significantly associated with a decrease of 42% in the risk of poor fertilization rate (≤50%). The higher antioxidant activity (CAT and TAC) in follicular fluid might positively impact specific IVF outcomes.

Cumulus Extracellular Matrix Is an Important Part of Oocyte Microenvironment in Ovarian Follicles: Its Remodeling and Proteolytic Degradation

The extracellular matrix (ECM) is an essential structure with biological activities. It has been shown that the ECM influences gene expression via cytoskeletal components and the gene expression is dependent upon cell interactions with molecules and hormones. The development of ovarian follicles is a hormone dependent process. The surge in the luteinizing hormone triggers ovulatory changes in oocyte microenvironment. In this review, we discuss how proteolytic cleavage affects formation of cumulus ECM following hormonal stimulation; in particular, how the specific proteasome inhibitor MG132 affects gonadotropin-induced cytoskeletal structure, the organization of cumulus ECM, steroidogenesis, and nuclear maturation. We found that after the inhibition of proteolytic cleavage, gonadotropin-stimulated oocyte-cumulus complexes (OCCs) were without any signs of cumulus expansion; they remained compact with preserved cytoskeletal F-actin-rich transzonal projections through the oocyte investments. Concomitantly, a significant decrease was detected in progesterone secretion and in the expression of gonadotropin-stimulated cumulus expansion-related transcripts, such as HAS2 and TNFAIP6. In agreement, the covalent binding between hyaluronan and the heavy chains of serum-derived the inter-alpha-trypsin inhibitor, essential for the organization of cumulus ECM, was missing.

Compromised Cumulus-Oocyte Complex Matrix Organization and Expansion in Women with PCOS

The cumulus-oocyte complex (COC) matrix plays a critical role in the ovulation and fertilization process and a major predictor of oocyte quality. Proteomics studies of follicular fluid showed differential expression of COC matrix proteins in women with polycystic ovary syndrome (PCOS), indicating altered COC matrix in these women. In the present study, we aimed to understand COC matrix gene induction in humans and its probable dysfunction in women with PCOS. Animal studies have shown that amphiregulin (AREG) and growth differentiation factor-9 (GDF-9) are important in the induction of COC matrix genes which are involved in cumulus expansion. The effects of AREG and GDF-9 on expression of tumor necrosis factor alpha induced protein 6 (TNFAIP6) and hyaluronan synthase 2 (HAS2) on human cumulus granulosa cells (CGCs) and murine COC expansion were evaluated. Further time-dependent effects of growth factor supplementation on these gene expressions in CGCs from PCOS and control women were compared. Follicular fluid from PCOS showed reduced COC matrix expansion capacity, using murine COCs. Expression of COC matrix genes TNFAIP6 and HAS2 were significantly reduced in CGCs of PCOS. Treatment of CGCs with AREG and GDF-9 together induced expression of both these genes in controls and could only restore HAS2 but not TNFAIP6 expression in PCOS. Our results suggest that the reduced potential of follicular fluid to support COC expansion, altered expression of structural constituents, and intrinsic defects in granulosa cells of women with PCOS may contribute to the aberrant COC organization and expansion in PCOS, thus affecting fertilization.

Modulation of hyaluronan signaling as a therapeutic target in human disease

The extracellular matrix is an active participant, modulator and mediator of the cell, tissue, organ and organismal response to injury. Recent research has highlighted the role of hyaluronan, an abundant glycosaminoglycan constituent of the extracellular matrix, in many fundamental biological processes underpinning homeostasis and disease development. From this basis, emerging studies have demonstrated the therapeutic potential of strategies which target hyaluronan synthesis, biology and signaling, with significant promise as therapeutics for a variety of inflammatory and immune diseases. This review summarizes the state of the art in this field and discusses challenges and opportunities in what could emerge as a new class of therapeutic agents, that we term "matrix biologics".

The Function of Cumulus Cells in Oocyte Growth and Maturation and in Subsequent Ovulation and Fertilization

Cumulus cells (CCs) originating from undifferentiated granulosa cells (GCs) differentiate in mural granulosa cells (MGCs) and CCs during antrum formation in the follicle by the distribution of location. CCs are supporting cells of the oocyte that protect the oocyte from the microenvironment, which helps oocyte growth and maturation in the follicles. Bi-directional communications between an oocyte and CCs are necessary for the oocyte for the acquisition of maturation and early embryonic developmental competence following fertilization. Follicle-stimulation hormone (FSH) and luteinizing hormone (LH) surges lead to the synthesis of an extracellular matrix in CCs, and CCs undergo expansion to assist meiotic resumption of the oocyte. The function of CCs is involved in the completion of oocyte meiotic maturation and ovulation, fertilization, and subsequent early embryo development. Therefore, understanding the function of CCs during follicular development may be helpful for predicting oocyte quality and subsequent embryonic development competence, as well as pregnancy outcomes in the field of reproductive medicine and assisted reproductive technology (ART) for infertility treatment.

Involvement of peroxiredoxin 2 in cumulus expansion and oocyte maturation in mice

Peroxiredoxin 2 (Prdx2), an antioxidant enzyme, is expressed in the ovary during the ovulatory process. The aim of the present study was to examine the physiological role of Prdx2 during ovulation using Prdx2-knockout mice and mouse cumulus-oocyte complex (COC) from WT mice. Two days of treatment of immature mice (21-23 days old) with equine chorionic gonadotrophin and followed by treatment with human chorionic gonadotrophin greatly impaired cumulus expansion and oocyte maturation in Prdx2-knockout but not wild-type mice. Treatment of COCs in culture with conoidin A (50µM), a 2-cys Prdx inhibitor, abolished epiregulin (EPI)-induced cumulus expansion. Conoidin A treatment also inhibited EPI-stimulated signal molecules, including signal transducer and activator of transcription-3, AKT and mitogen-activated protein kinase 1/2. Conoidin A treatment also reduced the gene expression of EPI-stimulated expansion-inducing factors (hyaluronan synthase 2 (Has2), pentraxin 3 (Ptx3), TNF-α induced protein 6 (Tnfaip6) and prostaglandin-endoperoxide synthase 2 (Ptgs2)) and oocyte-derived factors (growth differentiation factor 9 (Gdf9) and bone morphogenetic protein 15 (Bmp15)). Furthermore, conoidin A inhibited EPI-induced oocyte maturation and the activity of connexins 43 and 37. Together, these results demonstrate that Prdx2 plays a role in regulating cumulus expansion and oocyte maturation during the ovulatory process in mice, probably by modulating epidermal growth factor receptor signalling.

Sperm selection strategies and their impact on assisted reproductive technology outcomes

The application of assisted reproductive technologies (ART) has revolutionised the treatment of human infertility, giving hope to the patients previously considered incapable of establishing pregnancy. While semen analysis is performed to access whether a sample has an adequate number of viable, motile and morphologically normal sperm cells able to achieve fertilisation, sperm selection techniques for ART aim to isolate the most competent spermatozoon which is characterised by the highest fertilising potential. Based on the semen analysis results, the correct sperm selection technique must be chosen and applied. In this review, different sperm selection strategies for retrieving spermatozoa with the highest fertilising potential and their impact on ART outcomes are discussed. In addition, advantages and disadvantages of each method and the best suited techniques for each clinical scenario are described.

Follicular extracellular vesicles enhance meiotic resumption of domestic cat vitrified oocytes

Extracellular vesicles (EVs) contain multiple factors that regulate cell and tissue function. However, understanding of their influence on gametes, including communication with the oocyte, remains limited. In the present study, we characterized the proteome of domestic cat (Felis catus) follicular fluid EVs (ffEV). To determine the influence of follicular fluid EVs on gamete cryosurvival and the ability to undergo in vitro maturation, cat oocytes were vitrified using the Cryotop method in the presence or absence of ffEV. Vitrified oocytes were thawed with or without ffEVs, assessed for survival, in vitro cultured for 26 hours and then evaluated for viability and meiotic status. Cat ffEVs had an average size of 129.3 ± 61.7 nm (mean ± SD) and characteristic doughnut shaped circular vesicles in transmission electron microscopy. Proteomic analyses of the ffEVs identified a total of 674 protein groups out of 1,974 proteins, which were classified as being involved in regulation of oxidative phosphorylation, extracellular matrix formation, oocyte meiosis, cholesterol metabolism, glycolysis/gluconeogenesis, and MAPK, PI3K-AKT, HIPPO and calcium signaling pathways. Furthermore, several chaperone proteins associated with the responses to osmotic and thermal stresses were also identified. There were no differences in the oocyte survival among fresh and vitrified oocyte; however, the addition of ffEVs to vitrification and/or thawing media enhanced the ability of frozen-thawed oocytes to resume meiosis. In summary, this study is the first to characterize protein content of cat ffEVs and their potential roles in sustaining meiotic competence of cryopreserved oocytes.

Analysis of the equine "cumulome" reveals major metabolic aberrations after maturation in vitro

Background

Maturation of oocytes under in vitro conditions (IVM) results in impaired developmental competence compared to oocytes matured in vivo. As oocytes are closely coupled to their cumulus complex, elucidating aberrations in cumulus metabolism in vitro is important to bridge the gap towards more physiological maturation conditions. The aim of this study was to analyze the equine “cumulome” in a novel combination of proteomic (nano-HPLC MS/MS) and metabolomic (UPLC-nanoESI-MS) profiling of single cumulus complexes of metaphase II oocytes matured either in vivo (n = 8) or in vitro (n = 7).

Results

A total of 1811 quantifiable proteins and 906 metabolic compounds were identified. The proteome contained 216 differentially expressed proteins (p ≤ 0.05; FC ≥ 2; 95 decreased and 121 increased in vitro), and the metabolome contained 108 metabolites with significantly different abundance (p ≤ 0.05; FC ≥ 2; 24 decreased and 84 increased in vitro). The in vitro “cumulome” was summarized in the following 10 metabolic groups (containing 78 proteins and 21 metabolites): (1) oxygen supply, (2) glucose metabolism, (3) fatty acid metabolism, (4) oxidative phosphorylation, (5) amino acid metabolism, (6) purine and pyrimidine metabolism, (7) steroid metabolism, (8) extracellular matrix, (9) complement cascade and (10) coagulation cascade. The KEGG pathway “complement and coagulation cascades” (ID4610; n = 21) was significantly overrepresented after in vitro maturation. The findings indicate that the in vitro condition especially affects central metabolism and extracellular matrix composition. Important candidates for the metabolic group oxygen supply were underrepresented after maturation in vitro. Additionally, a shift towards glycolysis was detected in glucose metabolism. Therefore, under in vitro conditions, cumulus cells seem to preferentially consume excess available glucose to meet their energy requirements. Proteins involved in biosynthetic processes for fatty acids, cholesterol, amino acids, and purines exhibited higher abundances after maturation in vitro.

Conclusion

This study revealed the marked impact of maturation conditions on the “cumulome” of individual cumulus oocyte complexes. Under the studied in vitro milieu, cumulus cells seem to compensate for a lack of important substrates by shifting to aerobic glycolysis. These findings will help to adapt culture media towards more physiological conditions for oocyte maturation.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5836-5) contains supplementary material, which is available to authorized users.

CK1 inhibitor affects in vitro maturation and developmental competence of bovine oocytes

The objectives of present study were to evaluate the effect of casein kinase 1 (CK1) inhibition D4476 on in vitro maturation (IVM) and developmental competence of bovine oocytes. The cumulus oocyte complexes (COCs) were cultured in maturation medium with D4476 (0, 2, 5, 10, 20 μM) for 24 hr. After IVM and in vitro fertilization, through expansion average scores of cumulus cells (CCs), oocyte maturation efficiency, cleavage rate and blastocyst rate of zygote, we found 5 μM D4476 could increase the development potential of oocytes. After the COCs were treated with 5 μM D4476, the results of quantitative real-time PCR analysis, Lichen red staining and PI staining showed that under without affecting germinal vesicle breakdown and nuclear morphology, D4476 could significantly decrease CK1 and upregulate TCF-4 in oocytes. Furthermore, without influencing the level of Bad and CTSB, D4476 could significantly increase the expression of β-catenin, TCF-4, Cx43, MAPK, PTGS-2, PTX-3, TGS-6, Bax and Bcl-2 in CCs. Western blot analysis revealed that the addition of 5 μM D4476 during the maturation of COCs resulted in a lower level of Cx43 protein at 12 hr and a higher expression of Cx43 protein at 24 hr compared to the group without D4476. These results indicate that adding optimum D4476 (5 μM) to maturation medium is beneficial to maturity efficiency and development competence of bovine oocytes.

Gonadotropin regulation of ankyrin-repeat and SOCS-box protein 9 (ASB9) in ovarian follicles and identification of binding partners

Ankyrin-repeat and SOCS-box protein 9 (ASB9) is a member of the large SOCS-box containing proteins family and acts as the specific substrate recognition component of E3 ubiquitin ligases in the process of ubiquitination and proteasomal degradation. We previously identified ASB9 as a differentially expressed gene in granulosa cells (GC) of bovine ovulatory follicles. This study aimed to further investigate ASB9 mRNA and protein regulation, identify binding partners in GC of bovine ovulatory follicles, and study its function. GC were obtained from small follicles (SF: 2–4 mm), dominant follicles at day 5 of the estrous cycle (DF), and ovulatory follicles, 24 hours following hCG injection (OF). Analyses by RT-PCR showed a 104-fold greater expression of ASB9 in GC of OF than in DF. Steady-state levels of ASB9 in follicular walls (granulosa and theca cells) analyzed at 0, 6, 12, 18 and 24 hours after hCG injection showed a significant induction of ASB9 expression at 12 and 18 hours, reaching a maximum induction of 10.2-fold at 24 hours post-hCG as compared to 0 hour. These results were confirmed in western blot analysis showing strongest ASB9 protein amounts in OF. Yeast two-hybrid screening of OF-cDNAs library resulted in the identification of 10 potential ASB9 binding partners in GC but no interaction was found between ASB9 and creatine kinase B (CKB) in these GC. Functional studies using CRISPR-Cas9 approach revealed that ASB9 inhibition led to increased GC proliferation and modulation of target genes expression. Overall, these results support a physiologically relevant role of ASB9 in the ovulatory follicle by targeting specific proteins likely for degradation, contributing to reduced GC proliferation, and could be involved in the final GC differentiation into luteal cells.

Exposure to phthalates in couples undergoing in vitro fertilization treatment and its association with oxidative stress and DNA damage

This prospective study of 599 couples seeking fertility treatment and who were recruited between 2015 and 2017 was conducted to (a) explore the associations between phthalate exposure and in vitro fertilization (IVF) outcomes; and (b) examine the implication of oxidative stress as a mediator of these. We measured eight phthalate metabolites in two spot urine samples; oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide, catalase (CAT), and total antioxidant capacity in follicular fluid and seminal plasma. We also examined DNA damage in sperm and granulosa cells. Couples were exposed to a broad range of phthalate compounds and seven metabolites were detected in over 94% of the urine samples, whereas monobenzyl phthalate was found in only 24% of women and 26% of men. Our results showed high levels of seven urinary phthalate metabolites (except monobenzyl phthalate) and a notable increase in many oxidative stress markers in both follicular fluid and seminal plasma. However, their associations with exposure were rather limited. Multivariate binomial regression modeling showed higher levels of follicular CAT levels reduced the probability of fertilization rate (≤ 50%) [Adjusted relative risk (RR_adj) = 0.52, p = 0.005] and unsuccessful live birth (RR_adj = 0.592, p = 0.023). We observed a 46% decrease in the probability of clinical pregnancy in association with an elevated percentage of DNA in the tail (RR_adj = 0.536, p = 0.04). There was a 32% and 22% increase in the probability of clinical pregnancy and unsuccessful live birth associated with higher levels of mono-(2-ethylhexyl) phthalate (RR_adj = 1.32, p = 0.049) and monoethyl phthalate (RR_adj = 1.22, p = 0.032) in women, respectively. In contrast, the probability of clinical pregnancy reduced by 20% with higher levels of mono-(2-ethyl-5-carboxypentyl) phthalate (RR_adj = 0.797, p = 0.037) and 19.6% with mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) (RR_adj = 0.804, p = 0.041) in men. Other oxidative stress biomarkers or urinary phthalate metabolites showed suggestive relationships with certain IVF outcomes. Lastly, our results demonstrated that elevated levels of CAT in follicular fluid might have a positive impact on fertilization rate ≥ 50% and successful live birth. CAT seems to play a potential role in mediating the relationship between the risk of poor fertilization rate and MEOHP and mono-isobutyl phthalate. Additional data are required to understand the clinical implications of oxidative stress and its contribution to the reproductive toxicity of phthalate exposure.

Effect of DNA damage of cumulus oophorus cells and lymphocytes analyzed by alkaline comet assay on oocyte quality and intracytoplasmic sperm injection success among patients with polycystic ovary syndrome

AIM

Cumulus oophorus cells (COC) exhibit a close relationship with the oocytes. We aimed to determine the role of the DNA integrity of COC and lymphocytes on the oocyte and embryo quality and intracytoplasmic sperm injection (ICSI) success.

METHODS

The COC obtained with the mechanical denudation of each oocyte and the lymphocytes obtained on oocyte retrieval day from 69 infertile polycystic ovary syndrome (PCOS) patients were used. The tail length, tail moment and tail DNA percentage were evaluated using an alkaline comet assay. The oocytes and embryos were graded. Clinical pregnancy was defined as the presence of a gestational sac with a beating heart.

RESULTS

All of the DNA integrity parameters of the COC and lymphocytes were similar between the good and poor quality oocytes and between the good and poor quality embryos. There was no relationship between the DNA damage parameters and the fertilization and clinical pregnancy. The day 2 hormone levels, body mass index and age were negatively correlated with the DNA integrity parameters. No links were found between the embryo and oocyte scores and the DNA damage parameters.

CONCLUSION

The DNA integrity of the COC and lymphocytes did not seem to be related to the oocyte and embryo quality and ICSI success.

Assessment of Prostaglandin-Endoperoxide Synthase 2 and Versican gene expression profile from the cumulus cells: association with better in vitro fertilization outcomes

BACKGROUND

Current methods for determining superior embryo quality (morphological assessment) are unable to compensate for poor pregnancy outcomes. Due to the importance of the cumulus-oocyte complex and the value of cumulus cells (CCs) as markers of embryo health, we determined the association between the CCs gene expression of the Prostaglandin-Endoperoxide Synthase 2 (PTGS2) and Versican (VCAN) with pregnancy.

METHODS

One hundred forty-nine women, suffering from infertility and undergoing IVF, were included in this study (age: 29-46 years; BMI = 25.5 ± 5.0 kg/m²). Patients underwent a standard IVF protocol. CCs were isolated during oocyte retrieval, and their RNA was isolated using Trizol. The mRNA expression of PTGS2, VCAN, and L19 was measured by qPCR. The PVL index, (PTGS2 + VCAN)*L19_normalized, was determined for each oocyte. Clinical pregnancy was confirmed by β-hCG and the presence of a fetal heartbeat. Associations were determined by ROC curves or logistic regression.

RESULTS

There was no correlation between the PVL index and morphological scores. Using only single embryo transfers (SETs), we determined that the PVL index was associated with pregnancy (β-hCG: AUC = 0.87, 95%CI: 0.74-1.00) with an optimal cutoff value of 58.2. Using the complete cohort (consisting of SETs, and patients with 2, 3, or 4 embryos transferred), the presence of at least one embryo with a PVL index score ≥ 58.2 was associated with a greater probability of achieving pregnancy (β-hCG: odds ratio = 17.15, 95%CI: 6.82-43.18, p < 0.001).

CONCLUSION

Transferring at least one embryo with a PVL index score ≥ 58.2, generates a higher chance of achieving pregnancy.

Zona pellucida-binding protein 2 (ZPBP2) and several proteins containing BX7B motifs in human sperm may have hyaluronic acid binding or recognition properties

STUDY QUESTION

Are there novel hyaladherins in human sperm?

SUMMARY ANSWER

Zona pellucida-binding protein 2 (ZPBP2), containing a Link-like hyaluronic acid (HA)-binding domain, and several other proteins containing BX7B motifs, such as ADAM32 and Midkine, may be novel hyaladherins with HA-binding properties.

WHAT IS KNOWN ALREADY

HA-binding proteins (hyaladherins), which can bind HA surrounding the cumulus-oophorus complex, are distinct from hyases such as PH 20 (SPAM1) and are expressed by mature spermatozoa. Although HABP1 and CD44 are reasonably well characterized hyaladherins and the former has been implicated in sperm-oocyte interactions, the overall significance of sperm hyaladherins for male fertility is still poorly understood.

STUDY DESIGN, SIZE, DURATION

This was a laboratory-based investigation into human sperm hyaladherins undertaken as part of a three year PhD programme sponsored by the EU Marie Curie Training network, Reprotrain.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Protein homogenates of sperm obtained from young men of unknown fertility (N = 4) were partitioned into HA-binding and non-binding fractions by a protein affinity 'panning' method; their subsequent characterization was by liquid chromatography-tandem mass spectrometry (LC-MS-MS) and partitioning behaviour was confirmed by western blotting. Sequences of proteins from both fractions were submitted to PDBsum to look for orthologous entries (PDB codes) and all returned codes were queried against the matching protein using SAS (Sequences Annotated by Structure) looking for structural similarities between them. A systematic search for other common features of hyaladherins was also undertaken.

MAIN RESULTS AND THE ROLE OF CHANCE

The presence of BX7B sequence motifs found in several well-described hyaladherins including RHAMM was used to assess efficacy of potential hyaladherin partitioning by the HA substrate. The data showed that 50% (14/28) and 34.5% (28/81) of proteins in the bound and unbound fractions, respectively, contained these motifs (one-tailed Z-score = 1.45; P = 0.074), indicating weak discrimination by the substrate. Querying PDBsum with sequences for all bound proteins returned several PDB codes matching ZPBP2 with the HA-binding Link domain of the hyaladherin, CD44. Western blot analysis confirmed the affinity partitioning of proteins indicated by the LC-MS/MS results, with ADAM32 (containing two BX7B motifs) and ZPBP2 (containing a Link-like HA-binding domain) present only in the binding fraction. There remains the possibility that the putative hyaladherins uncovered by this study were coincidentally enriched by HA-binding.

LARGE SCALE DATA

The full proteomics data set is available on request.

LIMITATIONS REASONS FOR CAUTION

The protein extraction methods or the HA substrate used to pan them in this study were probably not ideal, as hyaladherins expected to be present in sperm homogenates (such as CD44 and RHAMM) were not detected.

WIDER IMPLICATIONS OF THE FINDINGS

The results provide evidence that ZPBP2, found only in the bound fraction, may have hyaladherin-like properties, which could reflect the evolutionary background context of contemporary sperm-oocyte interaction mechanisms.

STUDY FUNDING AND COMPETING INTEREST(S)

An EU Marie Curie Sklodowska Initial Training Network Scholarship, supporting Ms Torabi, is gratefully acknowledged. This project was also supported and funded by the Efficacy and Mechanism Evaluation Programme, a UK MRC and NIHR partnership (Grant No 11/14/ 34). There is no conflict of interest in relation to this work.

Effect of urokinase type plasminogen activator on in vitro bovine oocyte maturation

This study examines the impacts of the urokinase-type plasminogen activator (uPA) on the in vitro maturation (IVM) of bovine oocytes. Cumulus-oocyte complexes in IVM medium were treated with uPA, amiloride (an uPA inhibitor), dimethyl sulfoxide (DMSO) or left untreated (control group). After 24 h of IVM, oocytes were recovered for testing or were in vitro fertilized and cultured to the blastocyst stage. The factors examined in all groups were: (i) oocyte nuclear maturation (Hoëscht staining); (ii) oocyte cytoplasmic maturation (cortical granules, CGs, distribution assessed by LCA-FITC); (iii) oocyte and cumulus cell (CC) gene expression (RT-qPCR); and (iv) embryo development (cleavage rate and blastocyst yield). Oocytes subjected to uPA treatment showed rates of nuclear maturation and CG distribution patterns similar to controls (P > 0.05), whereas lower rates of oocyte maturation were recorded in the amiloride group (P < 0.05). Both in oocytes and CC, treatment with uPA did not affect the transcription of genes related to apoptosis, cell junctions, cell cycle or serpin protease inhibitors. In contrast, amiloride altered the expression of genes associated with cell junctions, cell cycle, oxidative stress and CC serpins. No differences were observed between the control and uPA group in cleavage rate or in blastocyst yield recorded on Days 7, 8 or 9 post-insemination. However, amiloride led to drastically reduced cleavage rate (28.5% vs 83.2%) and Day 9 embryo production (6.0% vs 21.0%) over the rates recorded for DMSO. These results indicate that the proteolytic activity of uPA is needed for successful oocyte maturation in bovine.

Regulation and roles of the hyaluronan system in mammalian reproduction

Hyaluronan (HA) is a non-sulphated glycosaminoglycan polymer naturally occurring in many tissues and fluids of mammals, including the reproductive system. Its biosynthesis by HA synthase (HAS1–3) and catabolism by hyaluronidases (HYALs) are affected by ovarian steroid hormones. Depending upon its molecular size, HA functions both as a structural component of tissues in the form of high-molecular-weight HA or as a signalling molecule in the form of small HA molecules or HA fragments with effects mediated through interaction with its specific cell-membrane receptors. HA is produced by oocytes and embryos and in various segments of the reproductive system. This review provides information about the expression and function of members of the HA system, including HAS, HYALs and HA receptors. We examine their role in various processes from folliculogenesis through oocyte maturation, fertilisation and early embryo development, to pregnancy and cervical dilation, as well as its application in assisted reproduction technologies. Particular emphasis has been placed upon the role of the HA system in pre-implantation embryo development and embryo implantation, for which we propose a hypothetical sequential model.

Differential activation of noncanonical SMAD2/SMAD3 signaling by bone morphogenetic proteins causes disproportionate induction of hyaluronan production in immortalized human granulosa cells

Successful fertilization depends upon proper cumulus-oocyte complex (COC) expansion. Synthesized by hyaluronan synthases (HASs), hyaluronan forms the backbone of the COC matrix and plays a critical role in COC expansion. This study investigated the effects and mechanisms of ovarian BMPs on HAS expression and hyaluronan production in human granulosa cells. Treatment with BMP4, BMP6, BMP7 or BMP15 induced differing levels of noncanonical SMAD2/3, but equal levels of canonical SMAD1/5/8, phosphorylation which were mirrored by differing levels of HAS2 up-regulation and hyaluronan production. The effects of BMP4 and BMP15 on HAS2 mRNA were partially reversed by knockdown of SMAD3, and blocked by knockdown of SMAD2+SMAD3 or SMAD4. BMP4-induced SMAD2/3 phosphorylation and HAS2 mRNA up-regulation were mediated by both BMP and activin/transforming growth factor-β type I receptors. Our results suggest differential activation of noncanonical SMAD2/SMAD3 signaling by BMPs causes disproportionate induction of HAS2 expression and hyaluronan production in immortalized human granulosa cells.

RHAMM deficiency disrupts folliculogenesis resulting in female hypofertility

The postnatal mammalian ovary contains the primary follicles, each comprising an immature oocyte surrounded by a layer of somatic granulosa cells. Oocytes reach meiotic and developmental competence via folliculogenesis. During this process, the granulosa cells proliferate massively around the oocyte, form an extensive extracellular matrix (ECM) and differentiate into cumulus cells. As the ECM component hyaluronic acid (HA) is thought to form the backbone of the oocyte-granulosa cell complex, we deleted the relevant domain of the Receptor for HA Mediated Motility (RHAMM) gene in the mouse. This resulted in folliculogenesis defects and female hypofertility, although HA-induced signalling was not affected. We report that wild-type RHAMM localises at the mitotic spindle of granulosa cells, surrounding the oocyte. Deletion of the RHAMM C-terminus in vivo abolishes its spindle association, resulting in impaired spindle orientation in the dividing granulosa cells, folliculogenesis defects and subsequent female hypofertility. These data reveal the first identified physiological function for RHAMM, during oogenesis, and the importance of this spindle-associated function for female fertility.

Utility of antioxidants during assisted reproductive techniques: an evidence based review

Assisted reproductive technology (ART) is a common treatment of choice for many couples facing infertility issues, be it due to male or female factor, or idiopathic. Employment of ART techniques, however, come with its own challenges as the in vitro environment is not nearly as ideal as the in vivo environment, where reactive oxygen species (ROS) build-up leading to oxidative stress is kept in check by the endogenous antioxidants system. While physiological amounts of ROS are necessary for normal reproductive function in vivo, in vitro manipulation of gametes and embryos exposes these cells to excessive ROS production either by endogenous or exogenous environmental factors. In this review, we discuss the sources of ROS in an in vitro clinical setting and the influence of oxidative stress on gamete/embryo quality and the outcome of IVF/ICSI. Sources of ROS and different strategies of overcoming the excessive generation of ROS in vitro are also highlighted. Endogenously, the gametes and the developing embryo become sources of ROS. Multiple exogenous factors act as potential sources of ROS, including exposure to visible light, composition of culture media, pH and temperature, oxygen concentration, centrifugation during spermatozoa preparation, ART technique involving handling of gamete/embryo and cryopreservation technique (freeze/thawing process). Finally, the use of antioxidants as agents to minimize ROS generation in the in vitro environment and as oral therapy is highlighted. Both enzymatic and non-enzymatic antioxidants are discussed and the outcome of studies using these antioxidants as oral therapy in the male or female or its use in vitro in media is presented. While results of studies using certain antioxidant agents are promising, the current body of evidence as a whole suggests the need for further well-designed and larger scale randomized controlled studies, as well as research to minimize oxidative stress conditions in the clinical ART setting.

Hyaluronan: a simple polysaccharide with diverse biological functions

Hyaluronan (HA) is a linear polysaccharide with disaccharide repeats of d-glucuronic acid and N-acetyl-d-glucosamine. It is evolutionarily conserved and abundantly expressed in the extracellular matrix (ECM), on the cell surface and even inside cells. Being a simple polysaccharide, HA exhibits an astonishing array of biological functions. HA interacts with various proteins or proteoglycans to organize the ECM and to maintain tissue homeostasis. The unique physical and mechanical properties of HA contribute to the maintenance of tissue hydration, the mediation of solute diffusion through the extracellular space and the lubrication of certain tissues. The diverse biological functions of HA are manifested through its complex interactions with matrix components and resident cells. Binding of HA with cell surface receptors activates various signaling pathways, which regulate cell function, tissue development, inflammation, wound healing and tumor progression and metastasis. Taking advantage of the inherent biocompatibility and biodegradability of HA, as well as its susceptibility to chemical modification, researchers have developed various HA-based biomaterials and tissue constructs with promising and broad clinical potential. This paper illustrates the properties of HA from a matrix biology perspective by first introducing the principles underlying the biosynthesis and biodegradation of HA, as well as the interactions of HA with various proteins and proteoglycans. It next highlights the roles of HA in physiological and pathological states, including morphogenesis, wound healing and tumor metastasis. A deeper understanding of the mechanisms underlying the roles of HA in various physiological processes can provide new insights and tools for the engineering of complex tissues and tissue models.

Molecular characterization and transcriptional regulation of a disintegrin and metalloproteinase with thrombospondin motif 1 (ADAMTS1) in bovine preovulatory follicles

The ovulatory process involves a complex remodeling of the extracellular matrix during which a desintegrin and metalloproteinase with thrombospondin motif 1 (ADAMTS1) is thought to play a key role, but its transcriptional regulation in bovine follicles remains largely unknown. The objectives of this study were to characterize the regulation of ADAMTS1 in bovine follicles before ovulation and to determine its transcriptional control in bovine granulosa cells. Regulation of ADAMTS1 was assessed using total RNA isolated from bovine preovulatory follicles obtained at various times after human chorionic gonadotropin treatment. Results from RT-PCR analyses showed that levels of ADAMTS1 mRNA were very low at 0 hours but increased at 6 to 24 hours after human chorionic gonadotropin in granulosa cells. To determine the regulatory mechanisms controlling ADAMTS1 gene expression in vitro, primary cultures of bovine granulosa cells were established, and treatment with forskolin up-regulated ADAMTS1 mRNA levels. Promoter activity assays, 5'-deletion, and site-directed mutagenesis identified a minimal region conferring full-length basal and forskolin-stimulated ADAMTS1 promoter activities, with both being dependent on Ebox cis-acting elements. EMSAs revealed upstream stimulating factor (USF) proteins as key trans-activating factors interacting with Ebox. Chromatin immunoprecipitation assays confirmed such interactions between USF and Ebox in vivo, and USF binding to Ebox elements was increased by forskolin treatment. ADAMTS1 promoter activity and mRNA expression were increased by forskolin and overexpression of the catalytic subunit of protein kinase A, but not by cotreatment with inhibitors of protein kinase A, ERK1/2, and epidermal growth factor receptor signaling pathways. Furthermore, treatment with a soluble epidermal growth factor induced ADAMTS1 mRNA expression in granulosa cells. Collectively, results from this study describe the gonadotropin/forskolin-dependent up-regulation of ADAMTS1 mRNA in granulosa cells of bovine preovulatory follicles in vivo and in vitro and identify for the first time some of the molecular mechanisms responsible for ADAMTS1 promoter activation in follicular cells of a large monoovulatory species.

Importance of the GDF9 signaling pathway on cumulus cell expansion and oocyte competency in sheep

Acquisition of developmental competency in cumulus oocyte complexes (COCs) is derived from endocrine hormones and oocyte secreted factors. The contribution of these factors in oocyte maturation and development is an active area of research. The objective of this research was to investigate whether growth differentiation factor 9 (GDF9) that is secreted by oocyte affects cumulus expansion and oocyte development in sheep. Immature ovine COCs were cultured in the presence of recombinant human GDF9 (rhGDF9), denuded oocytes, SB-431542, a specific inhibitor of activin-like kinase 4/5/7; or a combination of these factors. Routine in vitro maturation of COCs and denuded oocytes were used as external control samples. Cultured COCs were used for assessment of (1) cumulus expansion; (2) expression of cumulus-related transcripts including pentraxin 3, hyaluronan synthase 2 (HAS2), tumor necrosis factor alpha-induced protein 6, prostaglandin synthase 2, B-cell lymphoma 2 (BCL2), and Bcl2-associated X (BAX); and (3) yield and quality of embryo development. It was observed that cumulus expansion was not affected by any of these treatments. HAS2 mRNA expression confirmed this observation. In the presence of exogenous GDF9, cleavage rate was reduced, blastocyst rate did not differ from other groups, and trophectoderm cell number significantly increased. This suggests that exogenous GDF9 could improve embryo quality. It was also observed that oocyte secreted factors reduced proapoptotic BAX mRNA, and BCL2 mRNA expression was not significantly different from other groups. This study provides evidence that GDF9 signaling might have a minor influence on ovine cumulus expansion and oocyte development and that other signaling pathway(s) might have a dominant role.

The phenotype of hormone-related allergic and autoimmune diseases in the skin: annular lesions that lateralize

Introduction. Sexual dimorphism with an increased prevalence in women has long been observed in various autoimmune, allergic, and skin diseases. Recent research has attempted to correlate this female predilection to physiologic changes seen in the menstrual cycle in order to more effectively diagnose and treat these diseases. Cases. We present five cases of cutaneous diseases in women with annular morphology and distributive features that favor one side over the other. In all cases, skin disease improved with ovarian suppression. Conclusion. Sexual dimorphism in the innate and adaptive immune systems has long been observed, with females demonstrating a more vigorous immune response compared to males. Female sex hormones promote T and B lymphocyte autoreactivity and favor the humoral arm of adaptive immunity. In addition to ovarian steroidogenesis and immunity, intricate pathways coexist in order to engage a single oocyte in each cycle, while simultaneously sustaining the ovarian reserve. Vigorous proinflammatory, vasoactive, and pigment-related cytokines emerge during the demise of the corpus luteum, influencing peripherical sex hormone metabolism of the level of the macrophage and fibroblast. We propose that annular and lateralizing lesions are important manifestations of hormone-related inflammation and recognition of this linkage can lead to improved immune and reproductive health.

Increased prostaglandin E₂-EP2 signalling in cumulus cells of female mice sired by males with the Y-chromosome long-arm deletion

Cumuli oophori surrounding ovulated oocytes of B10.BR(Y(del)) females (sired by males with the Y-chromosome long-arm deletion) are more resistant to hyaluronidase digestion than cumuli oophori around eggs of genetically identical females but sired by males with the intact Y chromosome (B10.BR). This has been interpreted as a result of differences in paternal genome imprinting, which females of both groups inherit from their fathers. The following study shows that it is not hyaluronan, but rather excessive protein concentration, that makes the cumulus extracellular matrix of B10.BR(Y(del)) oocytes more resistant to enzymatic treatment. It was revealed, additionally, that cumulus cells around ovulating oocytes of B10.BR(Y(del)) females display higher surface accumulation of prostaglandin EP2 subtype receptors and higher expression of the Ptgs2 gene (encoding a rate-limiting enzyme of prostaglandin E₂ synthesis) in relation to the cells of control B10.BR females. The expression levels of the prostaglandin-dependent Tnfaip6 and Ccl2 genes were also altered in B10.BR(Y(del)) cumulus cells in a manner indicating increased prostaglandin signalling. The study provides further evidence for the divergence in reproductive phenotypes between B10.BR and B10.BR(Y(del)) female mice. It supports the hypothesis that genes of the Y-chromosome long arm may be involved in establishment of epigenetic marks in X-bearing spermatozoa.

Functional characterization of double-knockout mouse sperm lacking SPAM1 and ACR or SPAM1 and PRSS21 in fertilization

Mammalian fertilization requires sperm to penetrate the cumulus to reach the oocyte. Although sperm hyaluronidase has long been believed to participate in the penetration process, our previous works revealed that neither of two sperm hyaluronidases, SPAM1 and HYAL5, are essential for fertilization. In this study, we have produced double-knockout mice lacking SPAM1 and either one of two sperm serine proteases, ACR and PRSS21, and characterized the mutant sperm. The SPAM1/ACR- and SPAM1/PRSS21-deficient males were fertile, whereas epididymal sperm of the mutant mice exhibited a reduced capacity to fertilize the oocytes in vitro. Despite normal motility, the ability of sperm to traverse the cumulus matrix was more severely impaired by the loss of SPAM1 and ACR or SPAM1 and PRSS21 than by the loss of only SPAM1. Moreover, SPAM1/ACR- and SPAM1/PRSS21-deficient sperm accumulated on the surface (outer edge) of the cumulus more abundantly than SPAM1-deficient sperm. These results suggest that ACR or PRSS21 or both may function cooperatively with SPAM1 in sperm/cumulus penetration.

Can the partial deletion in the Y chromosome of male mice affect the reproductive efficiency of their daughters?

It has been previously shown that cumuli oophori around ovulated oocytes of B10.BR-Y(del) female mice (sired by males with the deleted Y chromosome) are more resistant to enzymatic treatment than cumuli oophori around eggs of control B10.BR females (having fathers with the intact Y chromosome). This can imply that some genes which influence the establishment of the imprinting pattern in male gametes are located in the region covered by the deletion. We hypothesize that the Y-dependent imprinting pattern, inherited by female offspring, affects stability of periovum layers within them. In the present study, cumulus-oocyte complexes ovulated by females from consomic strains: DBA, DBA-Y(BR), DBA-Y(del), and CBA, CBA-Y(BR), CBA-Y(del) were tested for their susceptibility to hyaluronidase digestion. The mean times for dispersal of cumulus cells surrounding oocytes of females from the backcross lines were convergent with the times typical for oocytes from strains being the donors of the Y chromosome (B10.BR or B10.BR-Y(del)) and differed clearly from pure DBA and CBA strains. It confirmed previous findings that Y chromosomes of fathers influence the properties of cumulus-oocyte complexes ovulated by their daughters. This influence is definitely stronger than the influence of the genetic background. Additionally, it was demonstrated that the cumuli oophori surrounding oocytes of B10.BR-Y(del) females exhibit increased resistance to penetration by spermatozoa in vitro, in comparison to the control B10.BR strain. This regularity was reflected in the decreased proportion of fertilized ova recovered from oviducts of B10.BR-Y(del) females mated with B10.BR-Y(del) males and in the lower litter sizes recorded for these pairs. The excessive stability of cumuli oophori typical for oocytes of females having Y(del) fathers may negatively affect their fertility, if they have partners producing poor quality sperm.

Improvement in embryo quality and pregnancy rates by using autologous cumulus body during icsi cycles

OBJECTIVE

To determine whether the addition of intact cumulus cell mass (ICM) to both embryo culture (EC) and embryo transfer (ET) improves embryo quality and pregnancy rates.

MATERIAL AND METHODS

A total of 133 infertile couples were included, of which 67 received ICM (study group) and 66 did not (control group). The ICM was obtained from a simple cutting of the cumulus corona oocyte complex (CCOC). A case control study design was used.

RESULTS

The clinical characteristics of the two groups before the embryo culturing step were similar with respect to age, estradiol level on the day of hCG and endometrial thickness on the day of embryo transfer (p>0.05). On the other hand study group with ICM had higher number of high quality embryos (3.1±1.4 vs 2.4±1.1, p=0.03), higher implantation rate (53.7% vs 34.8%, p=0.02) and higher ultrasound confirmation of gestational sac and fetal heart beat as ongoing pregnancy rates (44.7% vs 27.2%, p=0.04) compared to the control group without ICM.

CONCLUSION

Addition of ICM improves embryo quality and pregnancy rates. This is a cost-and time-effective simple procedure that shows great promise for the improvement of infertility treatment.

Cumulus cell gene expression following the LH surge in bovine preovulatory follicles: potential early markers of oocyte competence

Cumulus cells (CCs) are essential for oocytes to reach full development competency and become fertilized. Many major functional properties of CCs are triggered by gonadotropins and governed by the oocyte. Consequently, cumulus may reflect oocyte quality and is often used for oocyte selection. The most visible function of CCs is their ability for rapid extracellular matrix expansion after the LH surge. Although unexplained, LH induces the final maturation and improves oocyte quality. To study the LH signaling and gene expression cascade patterns close to the germinal vesicle breakdown, bovine CCs collected at 2 h before and 6 h after the LH surge were hybridized to a custom-made microarray to better understand the LH genomic action and find differentially expressed genes associated with the LH-induced oocyte final maturation. Functional genomic analysis of the 141 overexpressed and 161 underexpressed clones was performed according to their molecular functions, gene networks, and cell compartments. Following real-time PCR validation of our gene lists, some interesting pathways associated with the LH genomic action on CCs and their possible roles in oocyte final maturation, ovulation, and fertilization are discussed. A list of early potential markers of oocyte competency in vivo and in vitro is thereafter suggested. These early biomarkers are a preamble to understand the LH molecular pathways that trigger the final oocyte competence acquisition process in bovine.

The effects of roscovitine on cumulus cell apoptosis and the developmental competence of domestic cat oocytes

The developmental competence of cat oocytes matured in vitro is relatively poor when compared with that of in vivo oocytes. The study aimed to investigate the effect of roscovitine on the developmental competence of cat Felis catus oocytes matured in vitro. Cumulus-oocyte complexes (COCs) were classified as Grade I and II to III. Groups of COCs were cultured in 0, 12.5, 25, 50, 100, and 200 microM roscovitine for 24h and were either fixed to assess the stages of nuclear maturation (Experiment 1) or additionally matured in vitro for 24h before fixation (Experiment 2). In Experiment 3, cumulus cells from the COCs treated with roscovitine were examined for apoptosis. Experiment 4 examined the developmental competence of cat oocytes after roscovitine treatment and in vitro fertilization in terms of cleavage and morula and blastocyst formation rates. Roscovitine reversibly arrested cat oocytes at an immature stage in a dose-dependent manner. Roscovitine at 12.5 and 25 microM demonstrated less efficiency compared with that of other doses. However, higher doses of roscovitine induced cumulus cell apoptosis and resulted in a high number of degenerated oocytes after in vitro maturation. Roscovitine at 12.5 and 25 microM were therefore used to evaluate their effect on embryo development. Pretreatment with 12.5 and 25 microM roscovitine prior to in vitro maturation decreased the developmental competence of cat oocytes compared with that of non-roscovitine-treated controls. In conclusion, roscovitine reversibly maintained cat oocytes at the germinal vesicle stage without detrimental effect on nuclear maturation. However, it negatively affected cumulus cell viability and developmental competence.

Differences in collagen expression in cumulus cells after exposure to highly purified menotropin or recombinant follicle-stimulating hormone in a mouse follicle culture model

Extracellular matrix (ECM) formation by cumulus cells is an important process that determines fertilization and embryo quality. Several collagen types are present in the ovarian follicular ECM and are related to proliferation, steroidogenesis, and luteinization. In vitro mouse follicles can optimally grow and provide developmentally competent oocytes with 10 IU/L recombinant follicle-stimulating hormone (rFSH). As a model for superovulation, experiments with 100 IU/L rFSH or 100 IU/L highly purified menotropin (HP-hMG) exposure during antral growth were undertaken. Col4a1, Col4a2, and Col6a2 expression levels were analyzed at three time points during antral growth and at a 4-h interval up to 16 h after ovulation induction using quantitative PCR. The presence and induction of the collagen mRNA and protein were confirmed in cumulus from in vivo- and in vitro-grown follicles, and TGFBs 1 and 2 were assayed as potential regulators. The study revealed that exposure to 100 IU/L FSH, as in both superovulation conditions, significantly influenced the follicle morphology and slowed down nuclear maturation and mucification (P < 0.05). This coincided with an increased expression of the three collagens in the cumulus-oocyte complex at the end of antral growth and in the first hours following the ovulatory dose of human chorionic gonadotropin (P < 0.05). The increased expression might reflect a differentiation but is most likely due to a precocious luteinization of the cumulus. Growth in HP-hMG resulted in higher Tgfb1 mRNA and protein levels, fewer COCs with an increased collagen expression and with a more synchronous nuclear maturation. This suggests that the presence of luteinizing hormone activity tempered the effect of the elevated FSH dose.

Ovarian follicular dynamics: a review with emphasis on the bovine species. Part I: Folliculogenesis and pre-antral follicle development

Recent scientific research into pre-antral follicular dynamics has resulted in the discovery of a wide range of hormones and local factors that influence primordial follicle activation and contribute to follicular development. The putative role of several of these mediators in the follicle growth process has been elucidated by genetic and molecular investigations. Crucial questions, such as the mechanism for primordial follicle initiation and the interplay between oocyte and granulosa cells in this process, remain however unresolved. This review article commences with a description of the embryogenesis of the ovary and follicles. Next, the different stages in the development from primordial to pre-antral follicle are discussed. Thereafter, a short overview of the various in vitro models for the study of follicular dynamics is presented. Finally, an in-depth discussion of pre-antral follicle development engages in the current hypotheses regarding primordial follicle activation, and the role of gonadotrophins and angiogenesis.

Regulation of bovine tumor necrosis factor-alpha-induced protein 6 in ovarian follicles during the ovulatory process and promoter activation in granulosa cells

To study the regulation of bovine TNFalpha-induced protein 6 (TNFAIP6) prior to ovulation, preovulatory follicles obtained after the treatment with human chorionic gonadotropin (hCG) were used. RT-PCR analyses showed that levels of TNFAIP6 mRNA were low before hCG but significantly increased after hCG treatment in follicles. Further analyses and immunohistochemistry indicated that this increase in transcript and protein levels occurred in theca and granulosa cells. To investigate molecular mechanisms involved in TNFAIP6 transactivation, the activity of bovine TNFAIP6 promoter was studied in granulosa cell cultures. Mutant studies identified the minimal region conferring full-length promoter activity, in which activator protein-1 (AP1) and cAMP response element (CRE) elements were required for promoter activity. Overexpression of dominant-negative AP1 and activating transcription factor/cAMP response element-binding protein (CREB) inhibited forskolin-inducible promoter activity. DNA binding assays demonstrated the importance of AP1 and CRE for activity and identified JunD, FosB, Fra2, CREB1, and CREB2 as being part of the AP1 complex, and FosB, Fra2, and CREB1 for the CRE complex. Chromatin immunoprecipitation assays confirmed binding of these proteins with endogenous TNFAIP6 promoter. Treatment with forskolin, prostaglandin E2, and catalytic subunit protein kinase (cPKA) stimulated, but H89, PKA inhibitor peptide, and indomethacin inhibited, TNFAIP6 promoter activity and gene expression in granulosa cells. Collectively, this study is the first to describe that the ovulatory process in cows is associated with a gonadotropin-dependent induction of TNFAIP6 in ovarian follicles and provide the molecular basis through which AP1 and CRE sites and PKA activation played important roles in the regulation of TNFAIP6 in granulosa cells.

Cumulus cells and their extracellular matrix affect the quality of the spermatozoa penetrating the cumulus mass

OBJECTIVE

To investigate the role of the cumulus cells and the cumulus matrix in affecting the penetrability, morphology, acrosome reaction, and motility of human spermatozoa penetrating the cumulus oophorus.

DESIGN

Controlled experimental laboratory study.

SETTING

University gynecology unit.

PATIENT(S)

Women undergoing assisted reproduction treatment and men visiting the subfertility clinics.

INTERVENTION(S)

Human spermatozoa were allowed to penetrate through the cumulus oophorus and cell-depleted cumulus matrix in a capillary, and were treated with cumulus cell extract or hyaluronic acid.

MAIN OUTCOME MEASURE(S)

The morphology, acrosomal status, and motility of human spermatozoa were determined.

RESULT(S)

Fewer spermatozoa could penetrate the fresh cell-depleted matrix compared with intact cumulus oophorus. Spermatozoa that penetrated through the cumulus oophorus had higher percentages of normal morphology and acrosome reaction and had specific motility pattern. These effects were lost or reduced in the cell-depleted matrix that had been stored overnight. Hyaluronic acid, a main component of the cumulus matrix at concentration found in the cumulus oophorus, modulated sperm motility but did not affect spontaneous acrosome reaction. Cumulus cell extract did not affect sperm motility, but induced acrosome reaction.

CONCLUSION(S)

Both the cumulus matrix and the cumulus cells contribute to the effect of cumulus oophorus on spermatozoa penetrating through it.

Growth hormone and in vitro maturation of rhesus macaque oocytes and subsequent embryo development

PURPOSE

The objective of this study was to use a nonhuman primate model to examine the effects of growth hormone (GH) on oocyte in vitro maturation (IVM).

METHODS

Immunocytochemistry confirmed the presence of GH receptors in rhesus cumulus oocyte complexes and the cytoplasm of embryonic blastomeres. Recombinant human GH (r-hGH) was added to IVM medium and cumulus expansion, nuclear maturation, cytoplasmic maturation and embryo development were analyzed.

RESULTS

Cumulus expansion was highest in the presence of 1 and 10 ng/ml r-hGH. The addition of r-hGH during IVM increased the percentage of embryos progressing to at least the 9-16 cell stage. In a separate study, 100 ng/ml r-hGH was supplemented to IVM and embryo culture medium and no effect was observed.

CONCLUSIONS

The presence of GH receptors along with increased cumulus expansion and embryos progressing to the 9-16 cell stage supports the hypothesis that r-hGH may be involved in oocyte maturation.

Impact of the hyaluronan-rich tumor microenvironment on cancer initiation and progression

Hyaluronan acts as a microenvironmental stimulus that can influence the malignant phenotype of cancer cells. During cancer progression, hyaluronan assembles an extracellular matrix that is favorable for both the motility and proliferation of cancer cells and the recruitment of inflammatory and bone marrow-derived progenitor cells. The varied roles of this polysaccharide are regulated via multiple mechanisms involving biosynthesis, degradation, binding with other extracellular molecules, and activation of signaling pathways. Recent animal studies have provided evidence that aberrant biosynthesis of hyaluronan accelerates tumor growth through a diverse repertoire of host-tumor interactions, such as stromal cell recruitment, angiogenesis, lymphangiogenesis, and inflammation. Hyaluronan in the tumor microenvironment thus significantly impacts cancer initiation and progression via stroma-cancer cell interactions.