Epidermal growth factor improves developmental competence and embryonic quality of singly cultured domestic cat embryos

Epigen enhances the developmental potential of in vitro fertilized embryos by improving cytoplasmic maturation

Numerous growth factors contribute to oocyte maturation and embryonic development in vivo; however, only a few are understood. One such factor is epigen, a new member of the epidermal growth factor (EGF) family that is secreted by the granulosa cells of immature oocytes. We hypothesized that epigen may play a role in oocyte maturation, specifically in the nuclear and cytoplasmic aspects. This study aimed to investigate the effects of epigen on porcine oocyte maturation and embryo development in vitro. In this study, three different concentrations of epigen (3, 6, and 30 ng/mL) were added to tissue culture medium-199 (TCM-199) during in vitro maturation of porcine oocytes. A control group that did not receive epigen supplementation was also included. Mature porcine oocytes were fertilized, and the resulting zygotes were cultured until day 7. The levels of intracellular glutathione (GSH) and reactive oxygen species (ROS) were measured in the in vitro matured oocytes. At the same time, the expression patterns of genes related to apoptosis were detected in day 7 blastocysts (BLs) using real-time quantitative PCR Apoptosis was detected by annexin-V assays in mature oocytes. Data were analyzed using ANOVA and Duncan's test on SPSS, and results are presented as mean ± SEM. The group that received 6 ng/mL epigen had a significantly lower rate of germinal vesicle breakdown (GVBD) than the control group without affecting the nuclear maturation among the experimental groups. Among the treatment groups, the 6 ng/mL epigen group showed significantly higher levels of intracellular GSH and lower ROS production. Supplementation with 6 ng/mL epigen significantly improved blastocyst (BL) formation rates compared to those in the control and 3 ng/mL groups. Additionally, the blastocyst expansion rate was significantly higher with epigen supplementation (6 ng/mL). In the fertilization experiment, the group supplemented with 6 ng/mL epigen exhibited significantly higher levels of monospermy and fertilization efficiency and lower levels of polyspermy than the control group. This study indicated that adding epigen at a concentration of 6 ng/mL can significantly enhance the developmental potential of porcine oocytes fertilized in vitro. Specifically, the study found that epigen improves cytoplasmic maturation, which helps prevent polyspermy and emulates monospermic penetration.

Improvement of oocyte competence and in vitro oocyte maturation with EGF and IGF-I in Guinea pig model

In vitro maturation (IVM) system is an alternative method to superovulation protocols to obtain mature oocytes. Epidermal Growth Factor (EGF) and Insulin-like Growth Factor I (IGF-I) have been widely used in IVM medium in different species. Although the guinea pig is a valuable animal model for reproductive studies, IVM is rarely used. We aimed to establish a suitable in vitro production system using EGF and/or IGF-I during IVM to improve oocyte competence. Firstly, immunolocalization of EGF and IGF-I receptors in the ovary was assessed. An IVM dose-response experiment was performed with cumulus-oocyte complexes (COCs) supplemented with: 1) EGF [0, 10, 50, 100 ng/mL or 10% fetal calf serum (FCS)]; 2) IGF-I [0, 50, 100, 200 ng/mL or 10% FCS]; or 3) the concentrations of EGF and IGF-I which showed the best IVM index in the previous experiments, with or without Fetal Calf Serum (FCS). Cortical granule and mitochondria distribution patterns were determined in in vivo and in vitro-matured oocytes for the first time in this species. Apoptotic rate after IVM and oocyte competence by in vitro embryo development were evaluated. Immunohistochemistry results showed positive immunostaining of EGF and IGF receptors in corpus luteum, oocytes, granulosa and theca cells in follicles in all stages of development. Supplementation of IVM medium with 50 ng/mL EGF or 100 ng/mL IGF-I or their combination with FCS successfully led to oocyte nuclear and cytoplasmic maturation and reduced the apoptotic rate. Both growth factors improved oocyte competence during IVM in this species since early embryos were in vitro developed, showing better results when FCS was used in the IVM medium.

Lipid modulation during IVM increases the metabolism and improves the cryosurvival of cat oocytes

This study investigated the time course of lipid accumulation during IVM and assessed the role of lipid modulators added during IVM on lipid content, nuclear maturation, oxidative stress, mitochondrial activity, gene expression, and cryosurvival of cat oocytes. First, the lipid content of immature COCs was compared to those subjected to different IVM duration times (24, 28, and 32 h). Then, the lipid content was investigated after the use of different lipid modulators [conjugated linoleic acid (CLA), forskolin (FSK), l-carnitine (LC)]. Subsequently, both the CONTROL group and MIX 18 (CLA+FSK+LC) were compared regarding nuclear maturation, mitochondrial activity, reactive oxygen 19 species (ROS), and glutathione (GSH) levels, to the expression of SDHA, GDF9, BMP15, ZAR-1, 20 PRDX1, SIRT1, and SIRT3 genes (normalized by ACTB and YWHAZ genes); and to vitrification and 21 post-warming viability assessment. When not using any lipid modulator, an increase (P < 0.05) in lipid content could be observed after 28 h of IVM. The MIX group showed the greatest (P < 0.05) reduction in oocyte lipid content after 28 h of IVM. No difference (P > 0.05) was observed in the MII rate in the CONTROL (45%) and MIX (41%) groups and in mitochondrial activity ((1.00 ± 0.35 A U vs 1.19 ± 0.14 A U). Although ROS and GSH levels were higher (P < 0.05) in MIX than in CONTROL, the redox balance (ROS/GSH) was greater (P < 0.05) in the latter (C:1.00 ± 0.20b vs M:0.26 ± 0.06 a A.U). The GDF9, HSP70, PRDX1, and SIRT1 transcripts were downregulated (P < 0.05) in MIX-oocytes, compared to the CONTROL. After vitrification, MIX (74%) presented a higher (P < 0.05) viability compared to control (53%). In conclusion, MIX can reduce the total lipid content and improve viability after cryopreservation, however, it seems to affect the oocyte metabolism in a way that still needs to be better understood in the cat biological model.

Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

Simple Summary

This study was conducted with the aim of analyzing the morphokinetic parameters that determine the proper development of feline embryos in vitro. Our research was carried out using a time-lapse monitoring system shows that the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Abstract

The aim of this study was to analyze the morphokinetic parameters of feline embryos using a time lapse system. Oocytes matured in vitro were fertilized (IVF) and in vitro cultured in a time lapse-system (Primo Vision^®, Gothenburg, Sweden). The first cell division of embryos occurred between 17 h post insemination (hpi) and 38 hpi, with the highest proportion of embryos (46%) cleaving between 21 and 24 hpi. The timing of the first cleavage significantly affected further embryo development, with the highest development occurring in embryos that cleaved at 21–22 hpi. Embryos that cleaved very early (17–18 hpi) developed poorly to the blastocyst stage (2%) and none of the embryos that cleaved later than 27 hpi were able to reach the blastocyst stage. Morphological defects were observed in 48% of the embryos. There were no statistically significant differences between the timing intervals of the first cleavage division and the frequency of morphological defects in embryos. Multiple (MUL) morphological defects were detected in more than half (56%) of the abnormal embryos. The most frequent single morphological defects were cytoplasmic fragmentation (FR) (8%) and blastomere asymmetry (AS) (6%). Direct cleavage (DC) from 1–3 or 3–5 blastomeres, reverse cleavage (RC) and vacuoles were rarely observed (2–3%). The timing of blastocyst cavity formation is a very good indicator of embryo quality. In our study, blastocyst cavity formation occurred between 127–167 hpi, with the highest frequency of hatching observed in blastocysts that cavitated between 142–150 hpi. Blastocysts in which cavitation began after 161 h did not hatch. In conclusion, the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Optimization of in vitro embryo production and zygote vitrification for the indigenous Vietnamese Ban pig: The effects of different in vitro oocyte maturation systems

The Vietnamese Ban pig is a precious genetic resource that needs to be preserved. In vitro embryo production from in vitro matured (IVM) oocytes is an important tool for the utilization of cryopreserved porcine sperm. The aim of this study was to compare two media for the IVM of Ban pig oocytes. Immature oocytes were subjected to IVM either in a non-defined (TCM-199 + pig follicular fluid) or in a defined base medium (POM + epidermal growth factor). At the end of IVM, the oocytes were in vitro fertilized (IVF) with frozen Ban sperm. Ten hours after IVF, the oocytes were either subjected to orcein staining to check fertilization and maturation status or cultured in vitro for 7 days. There was no difference between the two IVM media in terms of percentages of oocyte maturation and blastocyst production. However, the percentage of male pronuclear formation after IVF and the total cell numbers in blastocysts were higher with the defined system. Zygotes obtained by the two IVM systems survived vitrification at similar rates. In conclusion, the two IVM systems were both effective for the production of Ban pig embryos; however, better embryo quality was achieved with the defined one.

A multilevel analysis identifies the different relationships between amino acids and the competence of oocytes matured individually or in groups

High-protein diets contribute to an increase in urea follicular concentrations associated with decreased fertility. Urea has been shown to interfere with the epidermal growth factor (EGF)/EGFR system, which has been shown to have a beneficial effect during in vitro maturation (IVM) of oocytes. Of note, the number of cumulus-oocyte complexes (COCs) in the maturation medium can change the maturation and the developmental competence of COCs. Therefore, it was hypothesized that, the presence of urea and EGF may have a differential effect on the depletion/appearance of AAs and competence of COCs matured individually (I-IVM system) or in groups (G-IVM system). In the G-IVM system, COCs increased consumption (depletion) of AAs compared with other groups in the presence of high-level urea (40 mg/dl) + EGF (10 ng/ml). In the I-IVM system, the non-cleaved COCs depleted more AAs than the cleaved COCs, in particular in the presence of urea. The combination of urea and EGF increased the depletion of AAs in the G-IVM system. However, the EGF abrogated the urea-induced depletion of AAs by the I-IVM COCs. The use of N-acetyl-L-cysteine as an EGFR inhibitor canceled urea-induced depletion of AAs. This shows the inhibiting effect of urea over the EGF/EGFR system. In the presence of urea + EGF, COCs had a lower degree of developmental competence than control in both I- and G-IVM systems. Arginine had the best predictive power to identify highly competent COCs in the G-IVM system, while glutamine was the best predictor of the cleavage in the I-IVM system. In conclusion, this multi-level study shows that COCs matured individually or in groups may have different association with AAs metabolism. These findings provide new insights into the relationships between AA metabolism and the subsequent developmental competence of COCs.

Ultra-diluted Folliculinum 6 cH impairs ovine oocyte viability and maturation after in vitro culture

This study investigated the effect of Folliculinum 6 cH on the oocyte meiosis resumption and viability rates, progesterone production and mitochondrial activity after in vitro maturation of cumulus-oocyte complexes (COCs) in sheep. Sheep ovaries were collected at a local slaughterhouse and COCs were recovered by slicing technique. The selected COCs were maturated in TCM199 (Control treatment), or control medium supplemented with 0.05% ethanol (v/v) (the vehicle of the homeopathic preparation - Ethanol treatment) or with Folliculinum 6 cH. After 24 h of in vitro maturation (IVM), oocytes were mechanically denuded and incubated with Hoechst 33342 and MitoTracker (0.5 μM) Orange CMTMRos for analysis of viability and chromatin configuration, and mitochondrial activity, respectively. The results showed that Folliculinum 6 cH addition increased oocyte degeneration and reduced meiotic resumption compared to the control (P < 0.05). Interestingly, the percentages meiotic resumption and oocyte maturation were lower in the Folliculinum 6 cH treatment compared to its vehicle (Ethanol treatment) (P < 0.05). On the other hand, when the treatments were compared, higher mitochondrial activity was observed in the Ethanol treatment (P < 0.05). In conclusion, contrary to its vehicle, the addition of Folliculinum 6 cH to the IVM medium promoted oocyte degeneration and affected negatively the mitochondrial distribution, impairing meiosis resumption.

Reactive oxygen species in reproduction: harmful, essential or both?

The process of embryonic development is crucial and radically influences preimplantation embryo competence. It involves oocyte maturation, fertilization, cell division and blastulation and is characterized by different key phases that have major influences on embryo quality. Each stage of the process of preimplantation embryonic development is led by important signalling pathways that include very many regulatory molecules, such as primary and secondary messengers. Many studies, both in vivo and in vitro, have shown the importance of the contribution of reactive oxygen species (ROS) as important second messengers in embryo development. ROS may originate from embryo metabolism and/or oocyte/embryo surroundings, and their effect on embryonic development is highly variable, depending on the needs of the embryo at each stage of development and on their environment (in vivo or under in vitro culture conditions). Other studies have also shown the deleterious effects of ROS in embryo development, when cellular tissue production overwhelms antioxidant production, leading to oxidative stress. This stress is known to be the cause of many cellular alterations, such as protein, lipid, and DNA damage. Considering that the same ROS level can have a deleterious effect on the fertilizing oocyte or embryo at certain stages, and a positive effect at another stage of the development process, further studies need to be carried out to determine the rate of ROS that benefits the embryo and from what rate it starts to be harmful, this measured at each key phase of embryonic development.

Hyaluronic acid and epidermal growth factor improved the bovine embryo quality by regulating the DNA methylation and expression patterns of the focal adhesion pathway

Focal adhesion pathway is one of the key molecular pathways affected by suboptimal culture conditions during embryonic development. The epidermal growth factor (EGF) and hyaluronic acid (HA) are believed to be involved in the focal adhesion pathway function by regulating the adherence of the molecules to the extracellular matrix. However, regulatory and molecular mechanisms through which the EGF and HA could influence the embryo development is not clear. Therefore, this study aimed to investigate the effect of continued or stage specific supplementation of EGF and/or HA on the developmental competence and quality of bovine preimplantation embryos and the subsequent consequences on the expression and DNA methylation patterns of genes involved in the focal adhesion pathway. The results revealed that, the supplementation of EGF or HA from zygote to the blastocysts stage reduced the level of reactive oxygen species and increased hatching rate after thawing. On the other hand, HA decreased the apoptotic nuclei and increased blastocyst compared to EGF supplemented group. Gene expression and DNA methylation analysis in the resulting blastocysts indicated that, combined supplementation of EGF and HA increased the expression of genes involved in focal adhesion pathway while supplementation of EGF, HA or a combination of EGF and HA during the entire preimplantation period changed the DNA methylation patterns of genes involved in focal adhesion pathway. On the other hand, blastocysts developed in culture media supplemented with EGF + HA until the 16-cell stage exhibited higher expression level of genes involved in focal adhesion pathway compared to those supplemented after the 16-cell stage. Conversely, the DNA methylation level of candidate genes was increased in the blastocysts obtained from embryos cultured in media supplemented with EGF + HA after 16-cell stage. In conclusion, supplementation of bovine embryos with EGF and/or HA during the entire preimplantation period or in a stage specific manner altered the DNA methylation and expression patterns of candidate genes involved in the focal adhesion pathway which was in turn associated with the observed embryonic developmental competence and quality.

Expressed proteins and activated pathways in conditioned embryo culture media from IVF patients are diverse according to infertility factors

OBJECTIVE

Given that the embryo culture medium secretome reflects the embryo development, we hypothesize that protein profiles are affected according to infertility factors, which can be responsible for detrimental embryonic developmental competence. The aim of this study was to screen the protein profile of conditioned embryo culture media in patients presenting deep infiltrating endometriosis (ENDO) and polycystic ovarian syndrome (PCOS) undergoing IVF, by proteomics approaches. The control group was constituted by tubal factor patients.

METHODS

Patients underwent in vitro fertilization (IVF) treatment as routine and oocytes were fertilized by ICSI. The embryos were group cultured until day 3 of development, and after transfer the culture media were collected. For the proteomics analysis, two pools of samples were prepared for groups CONTROL and PCOS, and 4 pools of samples for group DIE. Samples were prepared to deplete high abundant proteins and followed evaluated by high throughput proteomics approach.

RESULTS

The embryonic organ and tissue development were physiological functions activated, based on proteins identified in the 3 study groups of samples. The samples coming from DIE patients presented a high calcium activity and on the other hand, embryos coming from PCOS patients showed a decreased calcium action. Other pathways as grow factors through the EGF signaling pathway overexpressed in ENDO culture medium and protein kinase A in PCOS were also observed.

CONCLUSIONS

Proteomic embryonic secretome will advance our knowledge of early embryogenesis and additionally could lead to improved selection of embryos for transfer warrants further investigation.

ARTs in Wild Felid Conservation Programmes in Poland and in the World

With the exception of the domestic cat, all felid species (Felidae) are currently threatened with extinction in their natural habitat. To develop effective and optimal wild cat conservation programmes with assisted reproductive technology (ART) it is necessary to combine advances from different disciplines of science, starting from the biology of the species, through research into the population and habitat, assisted reproductive technologies, establishment of gene banks, developing bioinformatic systems, and ending with biodiversity and endangered species management. In the last few years knowledge of felid reproduction has expanded considerably thanks to comparative studies utilising the domestic cat as a research model for endangered wild cats. Basic reproductive techniques utilised in both domestic cat breeding and rescuing wild felid populations that are threatened with extinction include semen collection and cryopreservation, artificial insemination, oocyte collection, in vitro maturation, in vitro fertilisation, somatic cloning, and embryo transfer. The main directions in which assisted reproductive technologies are being developed in wild cat conservation implementations and the contribution of Polish research centres in advancing these methods are presented.

p66Shc is associated with hydrogen peroxide-induced oxidative stress in preimplantation sheep embryos

The low efficiency of in vitro embryo production is associated with oxidative stress induced by suboptimal culture conditions. p66Shc is a 66-kDa protein of the ShcA (Src homologous-collagen homolog) adaptor protein family, which is involved in signaling pathways involved in oxidative stress regulation, apoptosis induction, and aging. However, the functional role of p66Shc during the preimplantation development of sheep embryos is not understood. Our results showed that early-cleavage (≤28 hr) embryos had a higher developmental potential than late-cleavage (>28 hr) embryos. The poor quality of these late-cleavage embryos was associated with increased the transcripts and protein of p66Shc and decreased mitochondrial activity. In addition, exogenous hydrogen peroxide-induced oxidative stress significantly increased p66Shc protein abundance and suppressed embryonic development, which was ameliorated by antioxidant treatment. Notably, oxidative stress induced the nuclear localization of p66Shc and phosphorylated (Ser-36) p66Shc. Collectively, these observations suggest that p66Shc may be playing an important role in the regulation of oxidative stress during the preimplantation development of sheep embryos.

Influence of wideband visible light with an padding red component on the functional state of mice embryos and embryonic stem cells

It is known that visible light, including sunlight and laboratory lighting, adversely affect the development of embryos in vitro. In with article we present a technology for the synthesis of composite screens, capable to photoconvert UV and a part of the blue spectrum into red light with the maximum ~630 nm. It is established that the application of such transformed light with an evident red component raises the chances of embryos to survive and protects embryonic stem cells. To create photoconversion screens, the CdZn/Se quantum dots were obtained, the average size being about 7 nm. When the quantum dots are excited by electromagnetic waves of the UV and blue spectral range, photoluminescence is observed. The average photon energy for photoluminescence is of the order of 2 eV. On the basis of CdZn/Se quantum dots and methylphenylsiloxane polymer, light-transforming composite screens were made. In case of the light-transforming composite screen, the UV component disappeared from the energy spectrum, and the intensity of the blue region of the spectrum was reduced. On the contrary, in the red region (λ_max = 630 nm) one can see a little more than two-fold increase of intensity. It is shown that when exposed to 2-cell embryos by transformed light, the proportion of normally developing embryos increases by 20%, the number of dead embryos decreases twice, and number of dead and apoptotic cells was lower in blastocysts, what's decreased by 70%, as compared to the control group. When blastocysts are transferred to the feeder substrate, colonies of embryonic stem cells are formed. Cells obtained from blastocysts irradiated with transformed visible light are in a normal state in 90% of cases and did not change expression levels, biochemistry and morphology for at least 20 passages. It is assumed that the data obtained can be used for the design of systems of efficient cultivation of embryonic cells for tissue engineering and cell therapy.

Effects of vitrification and a Rho-associated coiled-coil containing protein kinase 1 inhibitor on the meiotic and developmental competence of feline oocytes

Oocyte cryopreservation is the technique of choice for the long-term storage of female gametes. However, it induces an irreversible loss of oocyte viability and function. We examined the effects of vitrification and a Rho-associated coiled-coil containing protein kinase 1 (ROCK1) inhibitor (ROCKi) on the meiotic and developmental competence of feline oocytes. We examined the expression of LIM kinase (LIMK) 1 and 2, with and without ROCKi treatment. Cumulus oocyte complexes (COCs) were matured in vitro with 0, 10, 20, and 40 µM ROCKi. The oocytes were subsequently assessed for maturation rate and embryo development following in vitro fertilization. We repeated the COC experiment, but vitrified and warmed the COCs prior to culture. We detected LIMK1 and LIMK2 expression in feline oocytes, which could be downregulated by ROCKi treatment. The ROCKi at 10 µM affected neither meiotic nor developmental competence (P > 0.05, versus control). However, high concentrations of ROCKi during maturation induced meiotic arrest at metaphase I. Appropriate concentrations of ROCKi significantly improved the normal fertilization rate of vitrified warmed oocytes (49.4 ± 3.4%) compared with that of the control (42.8 ± 8.6%, P < 0.05). The ROCKi also significantly improved the embryo cleavage rate (36.1 ± 3.8%) as compared with the non-treated control (27.4 ± 2.5%, P < 0.05). Thus, this study revealed that the main mediators of the ROCK cascade (LIM kinases) are expressed in feline oocytes. The ROCKi (10 µM) did not compromise the meiotic or developmental competence of feline oocytes. In addition, 10 µM ROCKi improved the cytoplasmic maturation of vitrified–warmed oocytes as indicated by their fertilization competence.

Fibroblast growth factor 10 markedly improves in vitro maturation of porcine cumulus-oocyte complexes

Growth factors synthesized by ovarian somatic cells affect cumulus cell expansion and oocyte maturation in vitro. Fibroblast growth factor 10 (FGF10), for example, is a known regulator of mammalian cumulus-oocyte complex maturation. In this study, we investigated the effects of 0, 5, 10, 50, and 100 ng/mL FGF10 (5F, 10F, 50F, and 100F, respectively) on in vitro cumulus cell expansion, oocyte maturation, and embryo development. The percentage of fully expanded cumulus cells at the oocyte's metaphase-II (MII) stage was significantly higher in the 10F-treated group than in the control. Transcript abundance of the cumulus cell expansion-related gene encoding hyaluronian synthase 2 (HAS2) in cumulus cells at oocyte germinal vesicle breakdown (GVBD) was significantly higher in the 10F- and 50F-treated groups compared to untreated controls, whereas the mRNA abundance of the protease cathepsin B (CTSB) at the oocyte MII stage was remarkably decreased in the 10F-treated group. The percentage of oocytes with normal spindles was greater in the 10F- and 50F-treated group at GVBD than in the other groups; the 5F-, 10F-, and 100F-treated groups were higher than the control; and the 50F-treated group was highest at MII. The abundance of GDF9 and BMP15 transcript at GVBD and BMP15 and CCNB1 transcripts at MII increased in the 10F-treated group. Cleavage rate, blastocyst formation rate, and total cell number were significantly higher in the 5F- to 50F-treated groups. These results demonstrate that FGF10 markedly improves cumulus cell expansion, oocyte maturation, and subsequent embryo development. Mol. Reprod. Dev. 84: 67-75, 2017. © 2016 Wiley Periodicals, Inc.

Actions of activin A, connective tissue growth factor, hepatocyte growth factor and teratocarcinoma-derived growth factor 1 on the development of the bovine preimplantation embryo

The reproductive tract secretes bioactive molecules collectively known as embryokines that can regulate embryonic growth and development. In the present study we tested four growth factors expressed in the endometrium for their ability to modify the development of the bovine embryo to the blastocyst stage and alter the expression of genes found to be upregulated (bone morphogenetic protein 15 (BMP15) and keratin 8, type II (KRT8)) or downregulated (NADH dehydrogenase 1 (ND1) and S100 calcium binding protein A10 (S100A10)) in embryos competent to develop to term. Zygotes were treated at Day 5 with 0.01, 0.1 or 1.0 nM growth factor. The highest concentration of activin A increased the percentage of putative zygotes that developed to the blastocyst stage. Connective tissue growth factor (CTGF) increased the number of cells in the inner cell mass (ICM), decreased the trophectoderm : ICM ratio and increased blastocyst expression of KRT8 and ND1. The lowest concentration of hepatocyte growth factor (HGF) reduced the percentage of putative zygotes becoming blastocysts. Teratocarcinoma-derived growth factor 1 increased total cell number at 0.01 nM and expression of S100A10 at 1.0 nM, but otherwise had no effects. Results confirm the prodevelopmental actions of activin A and indicate that CTGF may also function as an embryokine by regulating the number of ICM cells in the blastocyst and altering gene expression. Low concentrations of HGF were inhibitory to development.

Expression and Function of the Epidermal Growth Factor Receptor in Physiology and Disease

The epidermal growth factor receptor (EGFR) is the prototypical member of a family of membrane-associated intrinsic tyrosine kinase receptors, the ErbB family. EGFR is activated by multiple ligands, including EGF, transforming growth factor (TGF)-α, HB-EGF, betacellulin, amphiregulin, epiregulin, and epigen. EGFR is expressed in multiple organs and plays important roles in proliferation, survival, and differentiation in both development and normal physiology, as well as in pathophysiological conditions. In addition, EGFR transactivation underlies some important biologic consequences in response to many G protein-coupled receptor (GPCR) agonists. Aberrant EGFR activation is a significant factor in development and progression of multiple cancers, which has led to development of mechanism-based therapies with specific receptor antibodies and tyrosine kinase inhibitors. This review highlights the current knowledge about mechanisms and roles of EGFR in physiology and disease.