ECAT1 is essential for human oocyte maturation and pre-implantation development of the resulting embryos

Common dysmorphic oocytes and embryos in assisted reproductive technology laboratory in association with gene alternations

Amorphic or defected oocytes and embryos are commonly observed in assisted reproductive technology (ART) laboratories. It is believed that a proper gene expression at each stage of embryo development contributes to the possibility of a decent-quality embryo leading to successful implantation. Many studies reported that several defects in embryo morphology are associated with gene expressions during in vitro fertilization (IVF) treatment. There is lacking literature review on summarizing common morphological defects about gene alternations. In this review, we summarized the current literature. We selected 64 genes that have been reported to be involved in embryo morphological abnormalities in animals and humans, 30 of which were identified in humans and might be the causes of embryonic changes. Five papers focusing on associations of multiple gene expressions and embryo abnormalities using RNA transcriptomes were also included during the search. We have also reviewed our time-lapse image database with over 3000 oocytes/embryos to show morphological defects possibly related to gene alternations reported previously in the literature. This holistic review can better understand the associations between gene alternations and morphological changes. It is also beneficial to select important biomarkers with strong evidence in IVF practice and reveal their potential application in embryo selection. Also, identifying genes may help patients with genetic disorders avoid unnecessary treatments by providing preimplantation genetic testing for monogenic/single gene defects (PGT-M), reduce embryo replacements by less potential, and help scientists develop new methods for oocyte/embryo research in the near future.

Acute deletion of TET enzymes results in aneuploidy in mouse embryonic stem cells through decreased expression of Khdc3

TET (Ten-Eleven Translocation) dioxygenases effect DNA demethylation through successive oxidation of the methyl group of 5-methylcytosine (5mC) in DNA. In humans and in mouse models, TET loss-of-function has been linked to DNA damage, genome instability and oncogenesis. Here we show that acute deletion of all three Tet genes, after brief exposure of triple-floxed, Cre-ERT2-expressing mouse embryonic stem cells (mESC) to 4-hydroxytamoxifen, results in chromosome mis-segregation and aneuploidy; moreover, embryos lacking all three TET proteins showed striking variation in blastomere numbers and nuclear morphology at the 8-cell stage. Transcriptional profiling revealed that mRNA encoding a KH-domain protein, Khdc3 (Filia), was downregulated in triple TET-deficient mESC, concomitantly with increased methylation of CpG dinucleotides in the vicinity of the Khdc3 gene. Restoring KHDC3 levels in triple Tet-deficient mESC prevented aneuploidy. Thus, TET proteins regulate Khdc3 gene expression, and TET deficiency results in mitotic infidelity and genome instability in mESC at least partly through decreased expression of KHDC3.

Oocyte maturation abnormalities - A systematic review of the evidence and mechanisms in a rare but difficult to manage fertility pheneomina

A small proportion of infertile women experience repeated oocyte maturation abnormalities (OMAS). OMAS include degenerated and dysmorphic oocytes, empty follicle syndrome, oocyte maturation arrest (OMA), resistant ovary syndrome and maturation defects due to primary ovarian insufficiency. Genetic factors play an important role in OMAS but still need specifications. This review documents the spectrum of OMAS and to evaluate the multiple subtypes classified as OMAS. In this review, readers will be able to understand the oocyte maturation mechanism, gene expression and their regulation that lead to different subtypes of OMAs, and it will discuss the animal and human studies related to OMAS and lastly the treatment options for OMAs. Literature searches using PubMed, MEDLINE, Embase, National Institute for Health and Care Excellence were performed to identify articles written in English focusing on Oocyte Maturation Abnormalities by looking for the following relevant keywords. A search was made with the specified keywords and included books and documents, clinical trials, animal studies, human studies, meta-analysis, randomized controlled trials, reviews, systematic reviews and options written in english. The search detected 3,953 sources published from 1961 to 2021. After title and abstract screening for study type, duplicates and relevancy, 2,914 studies were excluded. The remaining 1,039 records were assessed for eligibility by full-text reading and 886 records were then excluded. Two hundred and twenty seven full-text articles and 0 book chapters from the database were selected for inclusion. Overall, 227 articles, one unpublished and one abstract paper were included in this final review. In this review study, OMAS were classified and extensively evaluatedand possible treatment options under the light of current information, present literature and ongoing studies. Either genetic studies or in vitro maturation studies that will be handled in the future will lead more informations to be reached and may make it possible to obtain pregnancies.

The effects of gallic acid and metformin on male reproductive dysfunction in diabetic mice induced by methylglyoxal: An experimental study

BACKGROUND

Diabetes mellitus is a disease that has reached a dangerous point. Today, nearly 500 million men and women around the world live with diabetes. Gallic acid (Gal) affects diabetes.

OBJECTIVE

To evaluate the effects of Gal and metformin (met) on the levels of glucose, insulin, testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), sperm count, antioxidant status, and histological changes in the testes of diabetic mice induced by methylglyoxal (MGO).

MATERIALS AND METHODS

In this experimental study, 50 male adult NMRI mice, weighting 25-30 gr, aged 3-4 months were randomly divided into five equal groups (n = 10/each). (i) Control (vehicle, normal saline), (ii) MGO (600 mg/kg/d) orally for 28 days, (iii) Gal (50 mg/kg/d), (iv) MGO+Gal, and (v) MGO+met (200 mg/kg/d). Gal and met were administered orally for 21 consecutive days after the induction of diabetes. Blood samples were taken at 24 hr after the latest doses of treatment. Histological assessment of the testis was done, and the epididymis sperm count was obtained. Antioxidant indices, glucose, insulin, LH, FSH, and testosterone levels were measured.

RESULTS

In the MGO group compared to the control group, insulin, glucose (p = 0.001), LH (p = 0.04) and malondialdehyde (p = 0.001) were increased. However, the level of testosterone (p = 0.001), seminiferous tubule diameters, epithelial height, sperm count, superoxide dismutase activity (p = 0.02), and testis volume (p = 0.01) were decreased. The results indicated that Gal and met ameliorated the MGO effects.

CONCLUSION

These findings suggested that the animals receiving MGO became diabetic. According to the results, Gal and met can effectively prevent MGO-induced diabetes. The effect of Gal was equivalent and sometimes better than metformin.

Does combination of estradiol and sesame oil improve the oocyte quality, embryo development and expressions of Zp3, E-cad, and Ctnnb1 genes in mice? An experimental study

BACKGROUND

Aging may reduce oocyte maturation, embryo quality, and fertility potential.

OBJECTIVE

To compare the effect of estradiol (E2) and sesame oil on oocyte and embryo quality between young and old mice.

MATERIALS AND METHODS

Sixty old and young female mice were divided in to two groups (30 mice/group, grouped by age). Each group was divided into three subgroups of mice treated with sesame oil, E2 + sesame oil, and normal saline as control group. After ovulation induction, some oocytes were considered for in vitro fertilization and the rest were assessed for morphological status. After obtaining the two-cell embryos, the embryos were collected to determine the expression of zona pellucida (ZP) glycoprotein 3, E-cadherin, and β-catenin genes and some of them followed until the blastocysts stage to evaluate the viability.

RESULTS

The findings showed that the mean ZP and perivitelline space thickness increased in the old mice that received the E2 + sesame oil treatment. The number of 2-cell embryos, blastocysts, and live cells were significantly higher in the old group treated with sesame oil respectively (p = 0.018, 0.002, and < 0.0001, respectively). The normal ZP shape and refractile body numbers increased in the old mice that were treated with sesame oil, respectively. The E-cadherin gene was downregulated in the treatment groups compared to the controls.

CONCLUSION

Sesame oil showed a better response in the old mice, because aging is associated with an increased rate of reactive oxygen species, causing deficiencies in both oocyte and embryo qualities.

Identification of novel, clinically correlated autoantigens in the monogenic autoimmune syndrome APS1 by proteome-wide PhIP-Seq

The identification of autoantigens remains a critical challenge for understanding and treating autoimmune diseases. Autoimmune polyendocrine syndrome type 1 (APS1), a rare monogenic form of autoimmunity, presents as widespread autoimmunity with T and B cell responses to multiple organs. Importantly, autoantibody discovery in APS1 can illuminate fundamental disease pathogenesis, and many of the antigens found in APS1 extend to more common autoimmune diseases. Here, we performed proteome-wide programmable phage-display (PhIP-Seq) on sera from a cohort of people with APS1 and discovered multiple common antibody targets. These novel APS1 autoantigens exhibit tissue-restricted expression, including expression in enteroendocrine cells, pineal gland, and dental enamel. Using detailed clinical phenotyping, we find novel associations between autoantibodies and organ-restricted autoimmunity, including a link between anti-KHDC3L autoantibodies and premature ovarian insufficiency, and between anti-RFX6 autoantibodies and diarrheal-type intestinal dysfunction. Our study highlights the utility of PhIP-Seq for extensively interrogating antigenic repertoires in human autoimmunity and the importance of antigen discovery for improved understanding of disease mechanisms.

Stereological study of organelle distribution in human oocytes at metaphase I

We have previously presented a stereological analysis of organelle distribution in human prophase I oocytes. In the present study, using a similar stereological approach, we quantified the distribution of organelles in human metaphase I (MI) oocytes also retrieved after ovarian stimulation. Five MI oocytes were processed for transmission electron microscopy and a classical manual stereological technique based on point-counting with an adequate stereological grid was used. Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction were used to compare the means of relative volumes (Vv) occupied by organelles. In all oocyte regions, the most abundant organelles were mitochondria and smooth endoplasmic reticulum (SER) elements. No significant differences were observed in Vv of mitochondria, dictyosomes, lysosomes, or SER small and medium vesicles, tubular aggregates and tubules. Significant differences were observed in other organelle distributions: cortical vesicles presented a higher Vv (P = 0.004) in the cortex than in the subcortex (0.96% vs 0.1%) or inner cytoplasm (0.96% vs 0.1%), vesicles with dense granular contents had a higher Vv (P = 0.005) in the cortex than in the subcortex (0.1% vs 0%), and SER large vesicles exhibited a higher Vv (P = 0.011) in the inner cytoplasm than in the subcortex (0.2% vs 0%). Future stereological analysis of metaphase II oocytes and a combined quantitative data of mature and immature oocytes, will enable a better understanding of oocyte organelle distribution during in vivo maturation. Combined with molecular approaches, this may help improve stimulation protocols and in vitro maturation methods.

KHDC3L mutation causes recurrent pregnancy loss by inducing genomic instability of human early embryonic cells

Recurrent pregnancy loss (RPL) is an important complication in reproductive health. About 50% of RPL cases are unexplained, and understanding the genetic basis is essential for its diagnosis and prognosis. Herein, we report causal KH domain containing 3 like (KHDC3L) mutations in RPL. KHDC3L is expressed in human epiblast cells and ensures their genome stability and viability. Mechanistically, KHDC3L binds to poly(ADP-ribose) polymerase 1 (PARP1) to stimulate its activity. In response to DNA damage, KHDC3L also localizes to DNA damage sites and facilitates homologous recombination (HR)-mediated DNA repair. KHDC3L dysfunction causes PARP1 inhibition and HR repair deficiency, which is synthetically lethal. Notably, we identified two critical residues, Thr145 and Thr156, whose phosphorylation by Ataxia-telangiectasia mutated (ATM) is essential for KHDC3L’s functions. Importantly, two deletions of KHDC3L (p.E150_V160del and p.E150_V172del) were detected in female RPL patients, both of which harbor a common loss of Thr156 and are impaired in PARP1 activation and HR repair. In summary, our study reveals both KHDC3L as a new RPL risk gene and its critical function in DNA damage repair pathways.

Recurrent pregnancy loss is an important complication in reproductive health, and about 50% of cases remain unexplained. This study shows that KHDC3L safeguards the genomic stability of human early embryonic cells, and damaging mutations in its gene cause recurrent pregnancy loss in humans.

Cancer Stem Cells or Tumor Survival Cells?

Research endeavors originally generated stem cell definitions for the purpose of describing normally sustainable developmental and tissue turnover processes in various species, including humans. The notion of investigating cells that possess a vague capacity of “stamm (phylum)” can be traced back to the late 19th century, mainly concentrating on cells that could produce the germline or the entire blood system. Lately, such undertakings have been recapitulated for oncogenesis, tumor growth, and cancer cell resistance to oncolytic therapies. However, due to the complexity and basic life-origin mechanisms comprising the genetic and epigenetic repertoire of the stemness in every developing or growing cell, presently there are ongoing debates regarding the biological essentials of the stem cell-like tumor initiation cells (ie, cancer stem cells; CSCs). This conceptual analysis focuses on the potential pitfalls of extrapolating that CSCs bear major traits of stemness. We propose a novel nomenclature of Tumor Survival Cells (TSCs) to further define tumor cells behaving like CSCs, based on the ruthless and detrimental features of Cancer Cell Survivology that appears fundamentally different from stem cell biology. Hence, precise academic separation of TSCs from all the stem cell-related labels applied to these unique tumor cells may help to improve scientific reasoning and strategies to decode the desperado-like survival behaviors of TSCs to eventually overcome cancer.