Preimplantation Stages Research Articles

Gender choice in assisted reproductive technologies: opportunities, dangers, prospects

Today, assisted reproductive technologies (ART) are a birth rate factor, which allows almost every person to give birth to a child, regardless of health. Fully reliable gender selection is only possible through pre-implantation diagnostics (PGD) as part of in vitro fertilization (IVF). Usually preference is given to boys, and the problem turns from individual family into a socio-gender problem, which can only be solved at the state level. While traditional methods of gender regulation involved selective abortions or killing of newborns («infanticide»), modern ART technically solves the issue at the pre-implantation stage, but entails ethical, psychological and financial problems that require special control. By prohibiting sex-selective abortions, the state limits the possibility of gender choice at the stage of conception to the risk of inherited diseases transmission due to fears of seriously disturbing natural gender balance, creating prerequisites for «genomocide». According to the National ART registries, Surveys of the International Federation of Fertility Societies for 2010–2019, Russian and foreign «hospital» statistics and the media, the article shows increase in the popularity of PGD that makes it possible to make a gender choice. In Russia, where the number of children in a family rarely exceeds two, and reproductive clinics perform all IVF programs, the choice of child’s gender is possible only with medically-justified PGD, and almost always performed at the expense of the patient. The only perspective in this situation is inclusion of such a PGD in the Compulsory Health Insurance system, when the gender of an unborn child becomes an additional, and its health — the main result.

Derivation of Maternal Epiblast Stem Cells from Haploid Embryos.

Pluripotent cells in the inner cell mass (ICM) or epiblast of mammalian embryos exhibit the capacity to differentiate into all cells represented in the three germ layers. Embryonic stem (ES) cells can be derived from the ICM of preimplantation stage blastocysts, while epiblast stem cells (EpiSCs) can be derived from the epiblast of postimplantation embryos or preimplantation stage embryos. The ability to derive distinct types of pluripotent cells from blastocyst-stage embryos suggests that optimization of culture conditions can promote self-renewal of various stem cell populations. Moreover, because mouse EpiSCs resemble human pluripotent stem (hPS) cells, EpiSCs are a useful model to study common and divergent mechanisms of self-renewal between orthologous species. In addition, studies have demonstrated that haploid embryos and ES cells can be derived from chemically activated oocytes. Here, we describe a protocol for deriving maternal (parthenogenetic/gynogenetic) EpiSCs (maEpiSCs) from haploid blastocyst-stage embryos. This protocol is suitable to establish an experimental model for the study of mechanisms of EpiSC self-renewal and differentiation.

Establishment of porcine nuclear transfer-derived embryonic stem cells using induced pluripotent stem cells as donor nuclei.

We investigated whether sequential reprogramming via porcine induced pluripotent stem cells (piPSCs) or exposure to oocyte cytoplasm following nuclear transfer could generate nuclear transfer-derived ESCs (piPSCs-ntESCs). Nuclear transfer embryos were reconstructed with piPSCs possessing a ZsGreen fluorescent marker for expression of exogenous Nanog and Lin28. Reconstructed oocytes developed to morphologically normal 8-cell/morulae (35/93, 37.6%) and blastocysts (12/93, 12.9%). Although most green fluorescent protein-positive blastocysts showed efficient outgrowth (8/10, 80%), none formed primary colonies and all cultures degenerated. Conversely, 15% of fluorescent positive 8-cell/morula stage embryos showed outgrowth (6/40), with three forming primary colonies (7.5%). All three were expanded and maintained as piPSC-ntESC lines. These cell lines expressed stem cell marker genes and proteins. Despite inactivation of one X chromosome, all piPSC-ntESC lines formed teratomas comprising derivatives from all three embryonic germ layers. Strong SSEA1, 3, and 4 expression was detected at the 8-cell/morula stage in embryos reconstructed from both piPSCs and porcine embryonic fibroblasts (PEFs). SSEA3 was notably absent from IVF controls at pre-implantation embryo stages. Finally, we attempted to establish ntESCs from 8-cell/morulae reconstructed with PEFs using the same culture conditions as those for piPSC-ntESC derivation. Although eight primary colonies arose from 107 embryos (7.5%), they all degenerated after the first passage culture. Early and sustained expression of key reprogramming regulatory factors may be critical for pluripotent stem cell derivation to derive piPSC-ntESCs from 8-cell/morula stages, while the expression of SSEAs may be involved in the initial stem cell colony formation phases.

Derivation of LIF-Independent Embryonic Stem Cells Using Inducible OCT4 Expression.

Pluripotent mouse embryonic stem (ES) cells, which are derived from the inner cell mass (ICM) of preimplantation stage embryos, are capable of self-renewing indefinitely in the presence of the external signal leukemia inhibitory factor (LIF), activation of Wnt signaling through inhibition of GSK3, and inhibition of MAP kinase/ERK kinase signaling. The OCT4 transcription factor is expressed highly in pluripotent cells and is a central transcriptional regulator of the pluripotent state. Here, we describe a protocol to culture ES cells in LIF-independent and serum-free media using an inducible OCT4 (iOCT4) ES cell model system. This protocol is sufficient to sustain ES cell self-renewal in vitro in defined conditions in the absence of external signals. LIF-independent iOCT4 ES cells are fully capable of differentiating following deactivation of the inducible OCT4 transgene.

Universal strategy for preimplantation genetic testing for cystic fibrosis based on next-generation sequencing.

We developed and applied a universal strategy for preimplantation genetic testing for all cystic fibrosis gene mutations (PGT-CF) based on next-generation sequencing (NGS). A molecular protocol was designed to diagnose all CF mutations at preimplantation stage. The detection of CF mutations was performed by direct gene sequencing and linkage strategy testing 38 specific SNPs located upstream and inside the gene for PGT-CF. Seventeen couples at risk of CF transmission decided to undergo PGT-CF. Trophectoderm cell biopsies were performed on days 5-6 blastocysts. PGT for aneuploidy (PGT-A) was performed from the same samples. Tested embryos were transferred on further natural cycles. PGT was performed on 109 embryos. Fifteen CF mutations were tested. PGT-CF and PGT-A were conclusive for, respectively, 92.7% and 95.3% of the samples. A mean of 24.1 SNPs was informative per couple. After single embryo transfer on natural cycle, 81.3% of the transferred tested embryos implanted. The present protocol based on the entire CFTR gene sequencingtogether with informative SNPs outside and inside the gene can be applied to diagnose all CF mutations at preimplantation stage.

Universal strategy for preimplantation genetic testing for cystic fibrosis based on next generation sequencing

PurposeWe developed and applied a universal strategy for preimplantation genetic testing for all cystic fibrosis gene mutations (PGT-CF) based on next-generation sequencing (NGS).MethodsA molecular protocol was designed to diagnose all CF mutations at preimplantation stage. The detection of CF mutations was performed by direct gene sequencing and linkage strategy testing 38 specific SNPs located upstream and inside the gene for PGT-CF. Seventeen couples at risk of CF transmission decided to undergo PGT-CF. Trophectoderm cell biopsies were performed on day 5–6 blastocysts. PGT for aneuploidy (PGT-A) was performed from the same samples. Tested embryos were transferred on further natural cycles.ResultsPGT was performed on 109 embryos. Fifteen CF mutations were tested. PGT-CF and PGT-A were conclusive for respectively 92.7% and 95.3% of the samples. A mean of 24.1 SNPs was informative per couple. After a single embryo transfer on natural cycle, 81.3% of the transferred tested embryos were implanted.ConclusionsThe present protocol based on the entire CFTR gene together with informative SNPs outside and inside the gene can be applied to diagnose all CF mutations at preimplantation stage.

THE FIRST CASE OF HUMAN GENOME EDITING: CRIMINAL LAW PERSPECTIVE

This article analyzes the legal assessment of the human genome modification experiment at the pre-implantation stage conducted by a group of scientists headed by He Jiankui, professor at the Southern University of Science and Technology (SUSTech) in Shenzhen, Guangdong Province, China, by means of the CRISPR/Cas9 technology. Chinese scholars have different opinions concerning He Jiankui’s experiment, but on the whole condemn it as illegal. Though CRISPR/Cas9 has been applied for quite a long time, the legislation of most developed countries is not ready to respond. The author of the article underlines the fact that despite the consolidated opinion of scholars, there is no binding international act which would restrict human genome editing. The author relies on Chinese sources in considering the main approaches to the assessment of He Jiankui’s actions in terms of criminal law (illegal medical activity, forgery of documents or fraud). Based on the analysis of Chinese criminal law doctrine, the author offers possible models of classifying separate actions related to human genome manipulation. The following cases of human genome manipulation are considered by the author as publicly dangerous and criminally liable: (a) when the embryo genome is changed by genetic engineering technologies for the purpose of its further implantation in the situation where the child’s parents are not aware of such intervention and its possible implications; (b) when genetic therapy or any other gene transfer (transgenesis) is applied to a person who is not aware of the nature of such manipulation and the possible implications of the application of the technology.

Loss of Mob1a/b impairs the differentiation of mouse embryonic stem cells into the three germ layer lineages

The Hippo pathway plays a crucial role in cell proliferation and apoptosis and can regulate stem cell maintenance and embryonic development. MOB kinase activators 1A and 1B (Mob1a/b) are key components of the Hippo pathway, whose homozygous deletion in mice causes early embryonic lethality at the preimplantation stage. To investigate the role of Mob1a/b in stem cell maintenance and differentiation, an embryonic stem cell (ESC) clone in which Mob1a/b could be conditionally depleted was generated and characterized. Although Mob1a/b depletion did not affect the stemness or proliferation of mouse ESCs, this depletion caused defects in differentiation into the three germ layers. Yap knockdown rescued the in vitro and in vivo defects in differentiation caused by Mob1a/b depletion, suggesting that differentiation defects caused by Mob1a/b depletion were Yap-dependent. In teratoma experiments, Yap knockdown in Mob1a/b-depleted ESCs partially restored defects in differentiation, indicating that hyperactivation of Taz, another effector of the Hippo pathway, inhibited differentiation into the three germ layers. Taken together, these results suggest that Mob1a/b or Hippo signaling plays a critical role in the differentiation of mouse ESCs into the three germ layers, which is dependent on Yap. These close relationship of the Hippo pathway with the differentiation of stem cells supports its potential as a therapeutic target in regenerative medicine.

Identification of lncRNAs by RNA Sequencing Analysis During in Vivo Pre-Implantation Developmental Transformation in the Goat.

Pre-implantation development is a dynamic, complex and precisely regulated process that is critical for mammalian development. There is currently no description of the role of the long noncoding RNAs (lncRNAs) during the pre-implantation stages in the goat. The in vivo transcriptomes of oocytes (n = 3) and pre-implantation stages (n=19) at seven developmental stages in the goat were analyzed by RNA sequencing (RNA-Seq). The major zygotic gene activation (ZGA) event was found to occur between the 8- and 16-cell stages in the pre-implantation stages. We identified 5,160 differentially expressed lncRNAs (DELs) in developmental stage comparisons and functional analyses of the major and minor ZGAs. Fourteen lncRNA modules were found corresponding to specific pre-implantation developmental stages by weighted gene co-expression network analysis (WGCNA). A comprehensive analysis of the lncRNAs at each developmental transition of high correlation modules was done. We also identified lncRNA-mRNA networks and hub-lncRNAs for the high correlation modules at each stage. The extensive association of lncRNA target genes with other embryonic genes suggests an important regulatory role for lncRNAs in embryonic development. These data will facilitate further exploration of the role of lncRNAs in the developmental transformation in the pre-implantation stage.

Single-Cell Transcriptome Analysis of Uniparental Embryos Reveals Parent-of-Origin Effects on Human Preimplantation Development.

To investigate the contribution of parental genomes to early embryogenesis, we profiled the single-cell transcriptomes of human biparental and uniparental embryos systematically from the 1-cell to the morula stage. We observed that uniparental embryos exhibited variable and decreased embryonic genome activation (EGA). Comparative transcriptome analysis identified 807 maternally biased expressed genes (MBGs) and 581 paternally biased expressed genes (PBGs) in the preimplantation stages. MBGs became apparent at the 4-cell stage and contributed to the initiation of EGA, whereas PBGs preferentially appeared at the 8-cell stage and might affect embryo compaction and trophectoderm specification. Regulatory network analysis revealed that DUX4, EGR2, and DUXA are key transcription factors in MBGs' expression; ZNF263 and KLF3 are important for PBGs' expression. We demonstrated that parent-specific DNA methylation might account for the expression of most PBGs. Our results provide a valuable resource to understand parental genome activation and might help to elucidate parent-of-origin effects in early human development.

Complement in Human Pre-implantation Embryos: Attack and Defense

It is essential for early human life that mucosal immunological responses to developing embryos are tightly regulated. An imbalance of the complement system is a common feature of pregnancy complications. We hereby present the first full analysis of the expression and deposition of complement molecules in human pre-implantation embryos. Thus, far, immunological imbalance has been considered in stages of pregnancy following implantation. We here show that complement activation against developing human embryos takes place already at the pre-implantation stage. Using confocal microscopy, we observed deposition of activation products on healthy developing embryos, which highlights the need for strict complement regulation. We show that embryos express complement membrane inhibitors and bind soluble regulators. These findings show that mucosal complement targets human embryos, and indicate potential adverse pregnancy outcomes, if regulation of activation fails. In addition, single-cell RNA sequencing revealed cellular expression of complement activators. This shows that the embryonic cells themselves have the capacity to express and activate C3 and C5. The specific local embryonic expression of complement components, regulators, and deposition of activation products on the surface of embryos suggests that complement has immunoregulatory functions and furthermore may impact cellular homeostasis and differentiation at the earliest stages of life.

Replication stress limits developmental potential of human preimplantation embryos

Human preimplantation embryos show abnormal nucleation and DNA damage, compromising cell cycle progression and developmental potential. The molecular mechanisms and timing of these abnormalities are unknown. We identified endogenous DNA damage and repair mechanisms in human embryos and developed a murine model to study developmental consequences of replication stress in preimplantation embryos. Prospective laboratory study of human and mouse embryos Endogenous DNA damage and repair pathways were evaluated in humans using donated oocytes (n=25) and embryos (n=20). Immunofluorescent staining detected DNA damage (γH2AX, RPA), repair (RPAS33, RPA S4/S8, Rad51, 53BP1), and micronucleation. Consequences of genomic instability were studied in a murine model using aphidicolin, a DNA polymerase inhibitor that increases endogenous chromosome fragility1. Mouse zygotes (n=500) were briefly exposed to aphidicolin in the first cell cycle, then evaluated at 1-cell, 2-cell, 4-8-cell and blastocyst stage. Immunofluorescent staining detected DNA damage and repair. Cleavage progression, blastulation and embryo quality were assessed versus controls. Human and mouse karyotypes were determined with NGS. Human preimplantation embryos show endogenous DNA damage, demonstrated by γH2AX, RPA and abnormal nucleation. Cleavage embryos had significantly greater foci and micronucleation vs blastocysts (γH2AX cleavage mean 2.3 vs blastocyst 1.0, p <0.0001; RPA cleavage mean 1.7 vs 0.3, p<0.0001; abnormal nucleation cleavage mean 15.9% vs blastocyst 4.2%, p<0.0001). DNA damage foci coincided with RPAS33, indicating RPA phosphorylation by G2 checkpoint kinase ATR, Rad51, indicating repair by homologous recombination, and 53BP1, indicating unrepaired DNA is passed to daughter cells. Aphidicolin-induced replication delay resulted in DNA damage (γH2AX and RPA), and RPAS33, indicating an ATR-dependent G2 checkpoint. Additional DNA repair mechanisms included Rad51 and 53BP1, similar to human embryos. Though some unreplicated DNA is tolerated in mitosis and compatible with euploidy, aphidicolin-induced under replication in the first cell cycle precipitated instability in later cell cycles, leading to decreased blastulation (45% after 8h aphidicolin vs 91.8% control, p<0.0001), and poor quality embryos as evidenced by significantly fewer total cells and inner cell mass with significantly greater DNA damage and micronucleation with increasing duration of aphidicolin exposure compared to controls. DNA damage responses to incomplete replication in G2 (ATR and Rad51), and the G1 response to unreplicated DNA (53BP1) mirror endogenous repair activity in human preimplantation embryos. Developmental consequences of replication stress likely persist beyond the preimplantation stage and may contribute to failed implantation or miscarriage. The murine model of genomic instability enables further study of these processes and the development of targeted therapeutics.

Origins of Intraindividual Genetic Variation in Human Fetuses

BackgroundIntraindividual copy number variation (CNV) origin is largely unknown. They might be due to aging and/or common genome instability at the preimplantation stage while contribution of preimplantation in human intraindividual CNVs occurrence is unknown. To address this question, we investigated mosaicism and its origin in the fetuses of natural conception.MethodsWe studied normal fetuses following therapeutic abortion due to maternal indications. We analyzed the genome of 22 tissues of each fetus by array comparative genomic hybridization for intraindividual CNVs. Each tissue was studied in 2 microarray experiments; the reciprocal aberrations larger than 40 Kb, identified by comparing tissues of each fetus, were subsequently validated using quantitative polymerase chain reaction.ResultsThrough intraindividual comparison, frequency of reciprocal events varied from 2 to 9. According to the distribution pattern of the frequent CNV in derivatives of different germ layers, we found that its origin is early development including preimplantation, whereas CNVs with low frequency have occurred in later stages. Shared CNVs in both fetuses were belonged to thymus and related to the functional role of genes located in these CNVs.ConclusionsThe origin of some of fetal CNVs is preimplantation stage. Each organ might inherit CNVs with an unpredictable pattern due to the extensive cell mixing/migration in embryonic development.

69. IMPROVED IVF SUCCESS OF COMBINED PGT-M AND PGT-A APPLICATIONS

Introduction Preimplantation Genetic Testing (PGT) has been performed since 1989 and utilized in the diagnosis of all genetic conditions at preimplantation stage ( 1 ). In the previous years, only a disorder could be diagnosed with the use of multiplex nested PCR in PGT applications. Increased use of trophectoderm biopsy and vitrification together with Whole Genome Amplification (WGA) technology enabled the detection of single gene disorders together with 24 chromosome screening. This approach allowed us to select healthy and chromosomally euploid embryos. Even though single gene disorder carrier patients are mostly young and fertile, they still have high risk of spontaneous miscarriage. In the recent years, it has been reported that when the embryos are screened for aneuploidy (PGT-A) in addition to single gene disorder testing (PGT-M), pregnancy rates can be increased from 45% to 68% and spontaneous miscarriage rates decreased from 15% to 5%. 34 single gene disorder patients, whose embryos were found to be healthy in terms of single gene disorder, were included in this study and these embryos were further screened for aneuploidy using Next Generation Sequencing (NGS) technology ( 2 ). Materials & Method On the 5th and 6th days of embryonic development, WGA was performed using SurePlex DNA Amplification System (Illumina, USA) and DOPlify (PerkinElmer Health Sciences - Australia). Following multiplex nested PCR on WGA samples, fragment analysis for haplotyping and sequence analysis for mutation detection were performed. Embryos found to be suitable for transfer regarding the single gene disorder have further been screened for aneuploidy using NGS technology with VeriSeq PGS Kit (Illumina, USA). Results This study was conducted for single gene disoder and 24 chromosome screening in 44 patients with an average age of 34. 280 embryos derived from these patients were included in PGT-M. Among 153 embryos that were found to be suitable for transfer after PGT-M, PGT-A was performed on 121 embryos upon patients' requests and 49% of these embryos were euploid. Embryo transfer could not be performed in 12 patients due to the absence of euploid embryos. According to the data we acquired, 64% pregnancy was achieved in the rest of the patients. Conclusion While pregnancy ratio can be improved with this approach, Allele drop out (ADO) and contamination errors are still major limitation which can lead to misdiagnosis of embryos. ADO ratio was demonstrated to be 25% in PGT for blastomere cells, whereas this ratio drops down to 5% when 5-7 cells obtained by trophectoderm biopsy are tested. Thus trophectoderm cells are more appropriate for PGT-M applications combined with PGT-A. Since stable and homogenous amplification of the entire genome is a crucial step, optimised WGA technologies will be a key factor in these applications.

The role of Kifc1, Kchn5 and miRNA-302 on in vitro development in 8-cell, morula and blastocyst stage of mouse embryos

Introduction: Embryo development is characterized by lack of cell cycle check-points and overexpression of core circadian oscillators. On previous report we have identified several genes over-and under-detected at human embryo blastomeres. In this study, we investigated the expression profile of Kcnh5, KIFC1 and miRNA-302 genes at three pre-implantation stages of mouse embryo development. Material and methods: Total RNA was extracted from mouse embyos at 8-cell, morula and blastocyst stage. The expression profile of Kcnh5, KIFC1 and miRNA-302 was assessed by RT-PCR and the results were normalized with G6pdh expression levels. Results: Kcnh5 showed absence of expression at all stages, indicating novel mechanisms of cell cycle control during blastomeres divisions. KIFC1 showed positive expression at all stages, with decreasing levels as the embryogenesis progresses. This finding indicates that KIFC1 may have more important role at early events. miRNA-302 showed increased levels of expression at all stages, with morula having the highest levels. Therefore, miRNA-302 might play an important role at the events that happen during morula stage such as compaction. Conclusions: Cell cycle control of blastomeres at early embryogenesis might be based on different mechanisms compared to somatic cells and more research is needed in order to reveal crucial cycling elements.

Defining Human Pluripotency.

Human pluripotent stem cells harbor the capacity to differentiate into cells from the three embryonic germ layers, and this ability grants them a central role in modeling human disorders and in the field of regenerative medicine. Here, we review pluripotency in human cells with respect to four different aspects: (1) embryonic development, (2) transcriptomes of pluripotent cell stages, (3) genes and pathways that reprogram somatic cells into pluripotent stem cells, and finally (4) the recent identification of the human pluripotent stem cell essentialome. These four aspects of pluripotency collectively culminate in a broader understanding of what makes a cell pluripotent.

The extent of DNA methylation anticipation due to a genetic defect in ICR1 in Beckwith-Wiedemann syndrome.

Beckwith-Wiedemann syndrome (BWS) is a representative imprinting disorder. Gain of methylation at imprinting control region 1 (ICR1-GOM), leading to the biallelic expression of IGF2 and silencing of H19, is one of the causative alterations in BWS. Twenty percent of BWS patients with ICR1-GOM have genetic defects in ICR1. Evidence of methylation anticipation in familial BWS patients with ICR1 genetic defects has been reported. However, the precise methylation pattern and extent of anticipation in these patients remain elusive. In addition, although age-related IGF2-DMR0 hypomethylation has been reported in the normal population, the period of its occurrence is unknown. In this study, we analyzed 10 sites (IGF2-DMR0, IGF2-DMR2, CTCF binding sites 1-7, and the H19 promoter) within the IGF2/H19 domain in familial BWS patients harboring a pathogenic variant in ICR1. We found that sites near the variant had relatively higher methylation in the first affected generation and observed methylation anticipation through maternal transmission in the next generation. The extent of anticipation was greater at sites far from the variant than nearby sites. The extended and severe GOM might be due to the insufficient erasure/demethylation of pre-acquired ICR1-GOM in primordial germ cells or during the preimplantation stage. In the normal population, age-related IGF2-DMR0 hypomethylation occurred; it became established by young adulthood and continued to old age. Further studies are needed to clarify (1) the precise mechanism of anticipation in patients with familial BWS and (2) the mechanism and biological significance of constitutive hypomethylation of IGF2-DMR0 and/or other imprinted differentially methylated regions.

EIF3f depletion impedes mouse embryonic development, reduces adult skeletal muscle mass and amplifies muscle loss during disuse.

In muscular cells, eukaryotic initiation factor subunit f (eIF3f) activates protein synthesis by allowing physical interaction between mechanistic target of rapamycin complex 1 (MTORC1) and ribosomal protein S6 kinase 1 (S6K1), although its physiological role in animals is unknown. A knockout approach suggests that homozygous mice carrying a null mutation of the eIF3f gene fail to develop and consequently die at early embryonic stage, whereas heterozygous mice associated with a partial depletion of eIF3f gene grow normally and are phenotypically indistinguishable from wild-type mice. Heterozygous mice express reduced eIF3f mRNA and protein levels in skeletal muscles and show diminished muscle mass associated with a decrease in the protein synthesis rate and an inhibition of the MTORC1 pathway. During hindlimb immobilization, heterozygous eIF3f mice display an exacerbated immobilization-induced muscle atrophy associated with reduced protein synthesis. These results highlight the essential role of eIF3f during embryonic development and its involvement in muscular homeostasis via protein synthesis regulation. Eukaryotic translation initiation factor 3, subunit F (eIF3f), a component of eIF3 complex, plays an important role in protein synthesis regulation, although its physiological functions are unknown. We generated and analysed mice carrying a null mutation in the eIF3f gene. We showed that homozygous eIF3f knockout fail to develop and that eIF3f-/- embryos die at an early stage of development but after the pre-implantation stage. However, disrupting one eIF3f allele does not affect growth, viability and fertility of heterozygous mice but, instead, reduces eIF3f mRNA and protein levels in all tissues examined. Although heterozygous mice are phenotypically indistinguishable from wild-type mice, they present a diminished body weight and a lean mass reduction associated with normal body size. Interestingly, skeletal muscles are mainly affected and display an altered cell size without modification of fibre number. Skeletal muscles of heterozygous mice show a deficiency in polysome content, a decrease in protein synthesis rate and an inhibition of the mechanistic target of rapamycin (MTOR) pathway. We then studied the effects of hindlimb immobilization that mimic muscle disuse on heterozygous mice aiming to further explore the involvement of eIF3f in protein synthesis. We found that eIF3f partial depletion amplifies muscle atrophy compared to wild-type mice. Mass and cross-sectional area decreases were associated with reduced MTOR pathway activation and protein synthesis rate. Taken together, our data indicate that eIF3f is essential for mice embryonic development and controls adult skeletal muscle mass via protein synthesis regulation in a MTOR-dependent manner.

Aminopeptidase N expression in the endometrium could affect endometrial receptivity

Aminopeptidase N (ANPEP) is a membrane-bound zinc-dependent peptidase. Although it is widely believed that ANPEP acts as an important angiogenesis regulatory factor, there are few studies about its function in the female reproductive system. In our previous research, we applied Isobaric Tags for Relative and Absolute Quantitation (iTRAQ) to analyze the influence of different controlled superovulation treatments for Assisted Reproductive Technology, In Vitro Fertilization and Embryo Transfer (IVF-ET)) patients from a global proteomic perspective to search for potential biomarkers associated with endometrium receptivity and embryo implantation. ANPEP is one of the proteins that demonstrated differential expression between different treatment groups and may be closely associated with endometrial receptivity. In this study, we assessed the expression of ANPEP in the endometrium of mice at different ages and found it to be highest in the mature period. We also detected ANPEP expression in the endometrium of IVF-ET patients in the proliferative, preimplantation and implantation stages, and the highest expression level of ANPEP was found in the last group. Human primary endometrial stromal cells were infected with an adenovirus expression vector containing the ANPEP gene and a green fluorescent protein (GFP) fusion protein; the mRNA levels of HOXA-10, LIF, and integrin β3 were found to be increased. Therefore, we conclude that ANPEP could be involved in the regulation of endometrial receptivity.

Assessment of Toxic Effects of Ochratoxin A in Human Embryonic Stem Cells.

Ochratoxin A (OTA) is a mycotoxin produced by different Aspergillus and Penicillium species, and it is considered a common contaminant in food and animal feed worldwide. On the other hand, human embryonic stem cells (hESCs) have been suggested as a valuable model for evaluating drug embryotoxicity. In this study, we have evaluated potentially toxic effects of OTA in hESCs. By using in vitro culture techniques, specific cellular markers, and molecular biology procedures, we found that OTA produces mild cytotoxic effects in hESCs by inhibiting cell attachment, survival, and proliferation in a dose-dependent manner. Thus, we suggest that hESCs provide a valuable human and cellular model for toxicological studies regarding preimplantation stage of human fetal development.