Maternal Undernutrition Induces Cell Signalling and Metabolic Dysfunction in Undifferentiated Mouse Embryonic Stem Cells.

Peri-conceptional environment can induce permanent changes in embryo phenotype which alter development and associate with later disease susceptibility. Thus, mouse maternal low protein diet (LPD) fed exclusively during preimplantation is sufficient to lead to cardiovascular, metabolic and neurological dysfunction in adult offspring. Embryonic stem cell (ESC) lines were generated from LPD and control NPD C57BL/6 blastocysts and characterised by transcriptomics, metabolomics, bioinformatics and molecular/cellular studies to assess early potential mechanisms in dietary environmental programming.

Blastocyst trophectoderm endocytic activation, a marker of adverse developmental programming.

The mouse preimplantation embryo is sensitive to its environment, including maternal dietary protein restriction, which can alter the developmental programme and affect lifetime health. Previously, we have shown maternal low-protein diet (LPD) causes a reduction in blastocyst mTORC1 signalling coinciding with reduced availability of branched-chain amino acids (BCAAs) in surrounding uterine fluid. BCAA deficiency leads to increased endocytosis and lysosome biogenesis in blastocyst trophectoderm (TE), a response to promote compensatory histotrophic nutrition.

Advanced maternal age perturbs mouse embryo development and alters the phenotype of derived embryonic stem cells.

Advanced maternal age (AMA) is known to reduce fertility, increases aneuploidy in oocytes and early embryos and leads to adverse developmental consequences which may associate with offspring lifetime health risks. However, investigating underlying effects of AMA on embryo developmental potential is confounded by the inherent senescence present in maternal body systems further affecting reproductive success. Here, we describe a new model for the analysis of early developmental mechanisms underlying AMA by the derivation and characterisation of mouse embryonic stem cell (mESC-like) lines from naturally conceived embryos.

The duration of embryo culture after mouse IVF differentially affects cardiovascular and metabolic health in male offspring.

Study Question: Do the long-term health outcomes following IVF differ depending upon the duration of embryo culture before transfer?

Summary Answer: Using a mouse model, we demonstrate that in male but not female offspring, adverse cardiovascular (CV) health was more likely with prolonged culture to the blastocyst stage, but metabolic dysfunction was more likely if embryo transfer (ET) occurred at the early cleavage stage.

What Is Known Already: ART associate with increased risk of adverse CV and metabolic health in offspring, and these findings have been confirmed in animal models in the absence of parental infertility issues. It is unclear which specific ART treatments may cause these risks.

Periconception maternal low-protein diet adversely affects male mouse fetal bone growth and mineral density quality in late gestation.

Adverse programming of adult non-communicable disease can be induced by poor maternal nutrition during pregnancy and the periconception period has been identified as a vulnerable period. In the current study, we used a mouse maternal low-protein diet fed either for the duration of pregnancy (LPD) or exclusively during the preimplantation period (Emb-LPD) with control nutrition provided thereafter and postnatally to investigate effects on fetal bone development and quality. This model has been shown previously to induce cardiometabolic and neurological disease phenotypes in offspring.

Origins of lifetime health around the time of conception: causes and consequences.

Parental environmental factors, including diet, body composition, metabolism, and stress, affect the health and chronic disease risk of people throughout their lives, as captured in the Developmental Origins of Health and Disease concept. Research across the epidemiological, clinical, and basic science fields has identified the period around conception as being crucial for the processes mediating parental influences on the health of the next generation. During this time, from the maturation of gametes through to early embryonic development, parental lifestyle can adversely influence long-term risks of offspring cardiovascular, metabolic, immune, and neurological morbidities, often termed developmental programming.

Insulin and branched-chain amino acid depletion during mouse preimplantation embryo culture programmes body weight gain and raised blood pressure during early postnatal life.

Mouse maternal low protein diet exclusively during preimplantation development (Emb-LPD) is sufficient to programme altered growth and cardiovascular dysfunction in offspring. Here, we use an in vitro model comprising preimplantation culture in medium depleted in insulin and branched-chain amino acids (BCAA), two proposed embryo programming inductive factors from Emb-LPD studies, to examine the consequences for blastocyst organisation and, after embryo transfer (ET), postnatal disease origin. Two-cell embryos were cultured to blastocyst stage in defined KSOM medium supplemented with four combinations of insulin and BCAA concentrations.

The Role of Maternal Nutrition During the Periconceptional Period and Its Effect on Offspring Phenotype.

The early preimplantation embryo has been rigorously studied for decades to understand inherent reproductive and developmental mechanisms driving its morphogenesis from before fertilisation through to and beyond implantation. Recent research has demonstrated that this short developmental window is also critical for the embryo's interaction with external, maternal factors, particularly nutritional status. Here, maternal dietary quality has been shown to alter the pattern of development in an enduring way that can influence health throughout the lifetime.

Cell signalling during blastocyst morphogenesis.

Blastocyst morphogenesis is prepared for even before fertilisation. Information stored within parental gametes can influence both maternal and embryonic gene expression programmes after egg activation at fertilisation. A complex network of intrinsic, cell-cell mediated and extrinsic, embryo-environment signalling mechanisms operates throughout cleavage, compaction and cavitation.

Do little embryos make big decisions? How maternal dietary protein restriction can permanently change an embryo's potential, affecting adult health.

Periconceptional environment may influence embryo development, ultimately affecting adult health. Here, we review the rodent model of maternal low-protein diet specifically during the preimplantation period (Emb-LPD) with normal nutrition during subsequent gestation and postnatally. This model, studied mainly in the mouse, leads to cardiovascular, metabolic and behavioural disease in adult offspring, with females more susceptible.

Amino acid composition of human uterine fluid: association with age, lifestyle and gynaecological pathology.

Study Question: Do the amino acid levels of human uterine fluid vary with age, BMI, phase of menstrual cycle, benign pathology or diet?

Summary Answer: The levels of 18 amino acids in human uterine fluid were shown to be affected only by maternal diet.

What Is Known Already: Murine, bovine and ovine uterine amino acid content has been reported, but no reliable data on the human exist. Murine studies have demonstrated that the intrauterine periconceptional nutritional environment is affected by maternal diet.

Metabolic induction and early responses of mouse blastocyst developmental programming following maternal low protein diet affecting life-long health.

Previously, we have shown that a maternal low protein diet, fed exclusively during the preimplantation period of mouse development (Emb-LPD), is sufficient to induce by the blastocyst stage a compensatory growth phenotype in late gestation and postnatally, correlating with increased risk of adult onset cardiovascular disease and behavioural dysfunction. Here, we examine mechanisms of induction of maternal Emb-LPD programming and early compensatory responses by the embryo. Emb-LPD induced changes in maternal serum metabolites at the time of blastocyst formation (E3.

Desmosomal adhesiveness is developmentally regulated in the mouse embryo and modulated during trophectoderm migration.

During embryonic development tissues remain malleable to participate in morphogenetic movements but on completion of morphogenesis they must acquire the toughness essential for independent adult life. Desmosomes are cell-cell junctions that maintain tissue integrity especially where resistance to mechanical stress is required. Desmosomes in adult tissues are termed hyper-adhesive because they adhere strongly and are experimentally resistant to extracellular calcium chelation.

Adaptive responses of the embryo to maternal diet and consequences for post-implantation development.

Maternal periconceptional (PC) nutrition, coupled with maternal physiological condition, can impact on reproductive performance and potential across mammalian species. Oocyte quality and embryo development are affected adversely by either nutrient restriction or excess. Moreover, the quality of maternal PC nutrition can have lasting effects through fetal development and postnatally into adulthood.

Maternal diet-induced obesity alters mitochondrial activity and redox status in mouse oocytes and zygotes.

The negative impact of obesity on reproductive success is well documented but the stages at which development of the conceptus is compromised and the mechanisms responsible for the developmental failure still remain unclear. Recent findings suggest that mitochondria may be a contributing factor. However to date no studies have directly addressed the consequences of maternal obesity on mitochondria in early embryogenesis.

Maternal low-protein diet during mouse pre-implantation development induces vascular dysfunction and altered renin-angiotensin-system homeostasis in the offspring.

Environmental perturbations during early mammalian development can affect aspects of offspring growth and cardiovascular health. We have demonstrated previously that maternal gestational dietary protein restriction in mice significantly elevated adult offspring systolic blood pressure. Therefore, the present study investigates the key mechanisms of blood pressure regulation in these mice.

Tight junction biogenesis during early development.

The tight junction (TJ) is an essential component of the differentiated epithelial cell required for polarised transport and intercellular integrity and signalling. Whilst much can be learnt about how the TJ is constructed and maintained and how it functions using a wide range of cellular systems, the mechanisms of TJ biogenesis within developmental models must be studied to gain insight into this process as an integral part of epithelial differentiation. Here, we review TJ biogenesis in the early mammalian embryo, mainly considering the mouse but also including the human and other species, and, briefly, within the amphibian embryo.

Low protein diet fed exclusively during mouse oocyte maturation leads to behavioural and cardiovascular abnormalities in offspring.

Early embryonic development is known to be susceptible to maternal undernutrition, leading to a disease-related postnatal phenotype. To determine whether this sensitivity extended into oocyte development, we examined the effect of maternal normal protein diet (18% casein; NPD) or isocaloric low protein diet (9% casein; LPD) restricted to one ovulatory cycle (3.5 days) prior to natural mating in female MF-1 mice.

The early human germ cell lineage does not express SOX2 during in vivo development or upon in vitro culture.

NANOG, POU5F1, and SOX2 are required by the inner cell mass of the blastocyst and act cooperatively to maintain pluripotency in both mouse and human embryonic stem cells. Inadequacy of any one of them causes loss of the undifferentiated state. Mouse primordial germ cells (PGCs), from which pluripotent embryonic germ cells (EGCs) are derived, also express POU5F1, NANOG, and SOX2.

Single-cell duplex RT-LATE-PCR reveals Oct4 and Xist RNA gradients in 8-cell embryos.

Background: The formation of two distinctive cell lineages in preimplantation mouse embryos is characterized by differential gene expression. The cells of the inner cell mass are pluripotent and express high levels of Oct4 mRNA, which is down-regulated in the surrounding trophectoderm. In contrast, the trophectoderm of female embryos contains Xist mRNA, which is absent from cells of the inner mass.

Adaptive responses by mouse early embryos to maternal diet protect fetal growth but predispose to adult onset disease.

Poor maternal nutrition during pregnancy can alter postnatal phenotype and increase susceptibility to adult cardiovascular and metabolic diseases. However, underlying mechanisms are largely unknown. Here, we show that maternal low protein diet (LPD), fed exclusively during mouse preimplantation development, leads to offspring with increased weight from birth, sustained hypertension, and abnormal anxiety-related behavior, especially in females.

Human embryos developing in vitro are susceptible to impaired epithelial junction biogenesis correlating with abnormal metabolic activity.

Background: Blastocyst biogenesis occurs over several cell cycles during the preimplantation period comprising the gradual expression and membrane assembly of junctional protein complexes which distinguish the outer epithelial trophectoderm (TE) cells from the inner cell mass (ICM). In the human, TE integrity and the formation of a junctional seal can often be impaired. Embryos likely to result in a successful pregnancy after transfer are mostly selected according to morphological criteria.

Mouse embryo culture induces changes in postnatal phenotype including raised systolic blood pressure.

A key factor in the use of assisted reproductive technologies (ART) for diverse species is the safety of procedures for long-term health. By using a mouse model, we have investigated the effect of in vitro culture and embryo transfer (ET) of superovulated embryos on postnatal growth and physiological activity compared with that of embryos developing in vivo. Embryo culture from two-cell to blastocyst stages in T6 medium either with or without a protein source reduced blastocyst trophectoderm and inner cell mass cell number compared with that of embryos developing in vivo.

Relative contribution of cell contact pattern, specific PKC isoforms and gap junctional communication in tight junction assembly in the mouse early embryo.

In mouse early development, cell contact patterns regulate the spatial organization and segregation of inner cell mass (ICM) and trophectoderm epithelium (TE) during blastocyst morphogenesis. Progressive membrane assembly of tight junctional (TJ) proteins in the differentiating TE during cleavage is upregulated by cell contact asymmetry (outside position) and suppressed within the ICM by cell contact symmetry (inside position). This is reversible, and immunosurgical isolation of the ICM induces upregulation of TJ assembly in a sequence that broadly mimics that occurring during blastocyst formation.

Contribution of JAM-1 to epithelial differentiation and tight-junction biogenesis in the mouse preimplantation embryo.

We have investigated the contribution of the tight junction (TJ) transmembrane protein junction-adhesion-molecule 1 (JAM-1) to trophectoderm epithelial differentiation in the mouse embryo. JAM-1-encoding mRNA is expressed early from the embryonic genome and is detectable as protein from the eight-cell stage. Immunofluorescence confocal analysis of staged embryos and synchronized cell clusters revealed JAM-1 recruitment to cell contact sites occurred predominantly during the first hour after division to the eight-cell stage, earlier than any other TJ protein analysed to date in this model and before E-cadherin adhesion and cell polarization.