BPA Exposure Affects Mouse Gastruloids Axial Elongation by Perturbing the Wnt/β-Catenin Pathway.

Mammalian embryos are very vulnerable to environmental toxicants (ETs) exposure. Bisphenol A (BPA), one of the most diffused ETs, exerts endocrine-disrupting effects through estro-gen-mimicking and hormone-like properties, with detrimental health effects, including on reproduction. However, its impact during the peri-implantation stages is still unclear.

Endocrine-Disrupting Chemicals, Gut Microbiota, and Human (In)Fertility-It Is Time to Consider the Triad.

The gut microbiota (GM) is a complex and dynamic population of microorganisms living in the human gastrointestinal tract that play an important role in human health and diseases. Recent evidence suggests a strong direct or indirect correlation between GM and both male and female fertility: on the one hand, GM is involved in the regulation of sex hormone levels and in the preservation of the blood-testis barrier integrity; on the other hand, a dysbiotic GM is linked to the onset of pro-inflammatory conditions such as endometriosis or PCOS, which are often associated with infertility. Exposure to endocrine-disrupting chemicals (EDCs) is one of the main causes of GM dysbiosis, with important consequences to the host health and potential transgenerational effects.

Multi- and Transgenerational Effects of Environmental Toxicants on Mammalian Reproduction.

Environmental toxicants (ETs) are an exogenous chemical group diffused in the environment that contaminate food, water, air and soil, and through the food chain, they bioaccumulate into the organisms. In mammals, the exposure to ETs can affect both male and female fertility and their reproductive health through complex alterations that impact both gametogeneses, among other processes. In humans, direct exposure to ETs concurs to the declining of fertility, and its transmission across generations has been recently proposed.

Functional and structural phenotyping of cardiomyocytes in the 3D organization of embryoid bodies exposed to arsenic trioxide.

Chronic exposure to environmental pollutants threatens human health. Arsenic, a world-wide diffused toxicant, is associated to cardiac pathology in the adult and to congenital heart defects in the foetus. Poorly known are its effects on perinatal cardiomyocytes.

Building Pluripotency Identity in the Early Embryo and Derived Stem Cells.

The fusion of two highly differentiated cells, an oocyte with a spermatozoon, gives rise to the zygote, a single totipotent cell, which has the capability to develop into a complete, fully functional organism. Then, as development proceeds, a series of programmed cell divisions occur whereby the arising cells progressively acquire their own cellular and molecular identity, and totipotency narrows until when pluripotency is achieved. The path towards pluripotency involves transcriptome modulation, remodeling of the chromatin epigenetic landscape to which external modulators contribute.

X-Chromosome Inactivation during Preimplantation Development and in Pluripotent Stem Cells.

X dosage compensation between XX female and XY male mammalian cells is achieved by a process known as X-chromosome inactivation (XCI). XCI initiates early during preimplantation development in female cells, and it is subsequently stably maintained in somatic cells. However, XCI is a reversible process that occurs in vivo in the inner cell mass of the blastocyst, in primordial germ cells or in spermatids during reprogramming.

Chronic cypermethrin exposure alters mouse embryonic stem cell growth kinetics, induces Phase II detoxification response and affects pluripotency and differentiation gene expression.

Worldwide uncontrolled use of synthetic pyrethroids contaminates water and soil leading to health hazards. Cypermethrin (CYP), the most used pyrethroid, induces detrimental effects on adults and embryos at different stages of development of several vertebrate species. In Mammals, CYP-induced alterations have been previously described in adult somatic cells and in post-implantation embryos.

S-Homocysteinylation effects on transthyretin: worsening of cardiomyopathy onset.

Background: L-Homocysteine (Hcy) is a non-proteinogenic α-amino acid synthesized from dietary methionine. In healthy humans, high Hcy levels are a risk factor for cardiovascular diseases, stroke and type 2 diabetes. A recent study reports that Hcy reacts with Cys of transthyretin (TTR), generating a stable covalent adduct.

Polychlorinated biphenyls reduce the kinematics contractile properties of embryonic stem cells-derived cardiomyocytes by disrupting their intracellular Ca dynamics.

Persistent organic pollutants are a group of chemicals that include polychlorinated biphenyls (PCBs). PCBs exposure during adult life increases incidence and severity of cardiomyopathies, whereas in utero exposure determines congenital heart defects. Being fat-soluble, PCBs are passed to newborns through maternal milk, impairing heart functionality in the adult.

Sertoli-immature spermatids disengagement during testis regression in the armadillo.

In nature, mammalian seasonal breeders undergo spermatogenetic arrest during the non-breeding season. In the large hairy armadillo Chaetophractus villosus, testis regression initiates with immature post-meiotic germ cells sloughing into the tubule lumen and continues with the death of the remaining spermatocytes. At the end of the regression period, only spermatogonia and Sertoli cells persist in the seminiferous epithelium.

Achilles' heel of pluripotent stem cells: genetic, genomic and epigenetic variations during prolonged culture.

Pluripotent stem cells differentiate into almost any specialized adult cell type of an organism. PSCs can be derived either from the inner cell mass of a blastocyst-giving rise to embryonic stem cells-or after reprogramming of somatic terminally differentiated cells to obtain ES-like cells, named induced pluripotent stem cells. The potential use of these cells in the clinic, for investigating in vitro early embryonic development or for screening the effects of new drugs or xenobiotics, depends on capability to maintain their genome integrity during prolonged culture and differentiation.

Chromosomal Abnormalities in Embryonic and Somatic Stem Cells.

The potential use of stem cells (SCs) for tissue engineering, regenerative medicine, disease modeling, toxicological studies, drug delivery, and as in vitro model for the study of basic developmental processes implies large-scale in vitro culture. Here, after a brief description of the main techniques used for karyotype analysis, we will give a detailed overview of the chromosome abnormalities described in pluripotent (embryonic and induced pluripotent SCs) and somatic SCs, and the possible causes of their origin during culture.

3D culture of ovarian follicles: a system towards their engineering?

Infertility in women is a health priority. Designing a robust culture protocol capable of attaining complete follicle growth is an exciting challenge, for its potential clinical applications, but also as a model to observe and closely study the sequence of molecular events that lie behind the intricate relationship existing between the oocyte and surrounding follicle cells. Here, we describe the procedures used to maintain the ovarian follicle 3D architecture employing a variety of in vitro systems and several types of matrices.

Arsenic trioxide alters the differentiation of mouse embryonic stem cell into cardiomyocytes.

Chronic arsenic exposure is associated with increased morbidity and mortality for cardiovascular diseases. Arsenic increases myocardial infarction mortality in young adulthood, suggesting that exposure during foetal life correlates with cardiac alterations emerging later. Here, we investigated the mechanisms of arsenic trioxide (ATO) cardiomyocytes disruption during their differentiation from mouse embryonic stem cells.

Loss of Sertoli-germ cell adhesion determines the rapid germ cell elimination during the seasonal regression of the seminiferous epithelium of the large hairy armadillo Chaetophractus villosus.

The armadillo Chaetophractus villosus is a seasonal breeder whose seminiferous epithelium undergoes rapid regression with massive germ cell loss, leaving the tubules with only Sertoli cells and spermatogonia. Here, we addressed the question of whether this regression entails 1) the disassembly of cell junctions (immunolocalization of nectin-3, Cadm1, N-cadherin, and beta-catenin, and transmission electron microscopy [TEM]); 2) apoptosis (immunolocalization of cytochrome c and caspase 3; TUNEL assay); and 3) the involvement of Sertoli cells in germ cell phagocytosis (TEM). We showed a dramatic reduction in the extension of vimentin filaments associated with desmosomelike junctions at the interface between Sertoli and germ cells, and an increased diffusion of the immunosignals of nectin-3, Cadm1, N-cadherin, and beta-catenin.

Mouse embryonic stem cells irradiated with γ-rays differentiate into cardiomyocytes but with altered contractile properties.

Embryonic stem cells (ESCs) for their derivation from the inner cell mass of a blastocyst represent a valuable in vitro model to investigate the effects of ionizing radiation on early embryonic cellular response. Following irradiation, both human and mouse ESCs (mESCs) maintain their pluripotent status and the capacity to differentiate into embryoid bodies and to form teratomas. Although informative of the maintenance of a pluripotent status, these studies never investigated the capability of irradiated ESCs to form specific differentiated phenotypes.

Constitutively released adenosine diphosphate regulates proplatelet formation by human megakaryocytes.

Background: The interaction of adenosine diphosphate with its P2Y(1) and P2Y(12) receptors on platelets is important for platelet function. However, nothing is known about adenosine diphosphate and its function in human megakaryocytes.

Design And Methods: We studied the role of adenosine diphosphate and P2Y receptors on proplatelet formation by human megakaryocytes in culture.

Mouse embryonic stem cells that survive γ-rays exposure maintain pluripotent differentiation potential and genome stability.

This study aimed to investigate the cell cycle, apoptosis, cytogenetics and differentiation capacity of mouse embryonic stem cells (mESCs) that survived a single dose of 2 or 5 Gy γ-rays during a period of up to 96 h of culture. After 2 Gy irradiation and 24 h culture, compared to control, a significant majority of cells was blocked at the G2/M phase and a massive apoptosis was recorded. Between 48 and 72 h post-irradiation, the parameters used to describe the cell cycle and apoptosis returned similar to those of control samples.

Gatekeeper of pluripotency: a common Oct4 transcriptional network operates in mouse eggs and embryonic stem cells.

Background: Oct4 is a key factor of an expanded transcriptional network (Oct4-TN) that governs pluripotency and self-renewal in embryonic stem cells (ESCs) and in the inner cell mass from which ESCs are derived. A pending question is whether the establishment of the Oct4-TN initiates during oogenesis or after fertilisation. To this regard, recent evidence has shown that Oct4 controls a poorly known Oct4-TN central to the acquisition of the mouse egg developmental competence.

The differentiation of cardiomyocytes from mouse embryonic stem cells is altered by dioxin.

2,3,7,8-Tetrachlorodibenzo-para-dioxin (TCDD) causes abnormalities during heart development. Cardiomyocytes derived from embryonic stem (ES) cells are a robust model for the study of early cardiomyogenesis. Here, we evaluated the effects of TCDD at key stages during the differentiation of mouse ES cells into cardiomyocytes analysing: (i) the transcription of lineage differentiation (Brachyury, Nkx-2.

Megakaryocyte-matrix interaction within bone marrow: new roles for fibronectin and factor XIII-A.

The mechanisms by which megakaryocytes (MKs) differentiate and release platelets into the circulation are not well understood. However, growing evidence indicates that a complex regulatory mechanism involving MK-matrix interactions may contribute to the quiescent or permissive microenvironment related to platelet release within bone marrow. To address this hypothesis, in this study we demonstrate that human MKs express and synthesize cellular fibronectin (cFN) and transglutaminase factor XIII-A (FXIII-A).

Quantitative variation of LINE-1 sequences in five species and three subspecies of the subgenus Mus and in five Robertsonian races of Mus musculus domesticus.

The quantitative variation of a conserved region of the LINE-1 ORF2 sequence was determined in eight species and subspecies of the subgenus Mus (M. m. domesticus, M.

Chromosome number variation in three mouse embryonic stem cell lines during culture.

Although mouse embryonic stem cell lines (mESCs) have been established since 1981, systematic studies about chromosomal changes during culture are lacking. In this study, we report the results of a cytogenetic analysis performed on three mESC lines (named UPV02, UPV06 and UPV08) cultured for a period of 3 months. At time intervals, the variation of the chromosome number together with the expression of markers of the undifferentiated status, i.

Mouse fibroblasts are reprogrammed to Oct-4 and Rex-1 gene expression and alkaline phosphatase activity by embryonic stem cell extracts.

A recent remarkable study has shown that when mouse NIH-3T3 fibroblasts are exposed to an embryonic stem cell (ESC) extract, the majority of them expresses the Oct-4 gene, form ESC-like colonies, and embryoid-like bodies that differentiate into cells of the three germ layers. The use of cell extracts for inducing cell dedifferentiation could be a powerful system to obtain large quantities of pluripotent cells. It is thus of crucial importance that the robustness of this method of cell transdifferentiation is tested by other laboratories before it is advanced to a more ambitious use in cell therapy programs.

Inhibition of gene amplification in telomerase deficient immortalized mouse embryonic fibroblasts.

Mutations in genes important for the preservation of genome stability can increase the frequency of gene amplification, a process relevant to tumor development. To investigate whether telomerase, the enzyme deputed to telomere maintenance, also plays a role in gene amplification, we studied the amplification of the carbamyl-P-synthetase, aspartate transcarbamilase, dihydro-orotase (CAD) gene in immortalized embryonic fibroblasts derived from telomerase knockout mice (mTERC(-/-)) of the first and of the sixth generation. As expected, in 9 out of 10 N-(phosphonacetyl)-L-aspartate (PALA) resistant clones derived from wild-type cells, CAD was amplified; in contrast, in none of the 30 PALA resistant clones isolated from the three mTERC(-/-) cell lines we could detect CAD amplification, indicating that, in the absence of telomerase activity, gene amplification is inhibited.