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

Changes in the Transcription of Proliferation- and Apoptosis-Related Genes in Embryos in Women of Different Ages under the Influence of Extracellular Vesicles from Donor Follicular Fluid In Vitro

We studied the influence of extracellular vesicles from the follicular fluid of a young donor on gene expression (MKI67, MYBL2, CCNB1, CCND1, CCNE1, CALM2, BAX, NDRG1, TP53I3, VEGF, VCAN, HAS2, CTSL2, PIBF1, RPL37, PFKP, GPX3, and AQP3) in embryos of women of different ages. According to nanoparticle tracking analysis data, the concentration of extracellular vesicles was 3.75±0.47×1011 particles/ml and the mean particle size was 138.78±9.90 nm. During co-culturing of the follicular fluid extracellular vesicles with blastocysts of young women, we observed significantly increased expression of mRNA for genes CTSL2, CCND1, CCNE1, VEGF and reduced expression of BAX gene mRNA in comparison with embryos in women of late reproductive age. We hypothesized that addition of extracellular vesicles of the oocyte follicular fluid from a young donor to the culture medium of embryos could slow down apoptosis process typical of blastocyst cells in women above 36 years.

Evaluation of the effect of boron derivatives on cardiac differentiation of mouse pluripotent stem cells

BACKGROUND

The heart is one of the first organs to form during embryonic development and has a very important place. So much that the formation of a functional heart is completed on the 55th day of human development and the 15th day of mouse development. Myocardial, endocardial and epicardial cells, which are derived from the mesoderm layer, are the cells that form the basis of the heart. Cardiac development, like other embryonic developments, is tightly controlled and regulated by various signaling pathways. The WNT signaling pathway is the most studied of these signaling pathways and the one with the clearest relationship with heart development. It is known that boron compounds and the Wnt/β-catenin pathway are highly correlated. Therefore, this study aimed to investigate the role of boron compounds in heart development as well as its effect on pluripotency of mouse embryonic stem cells for the first time in the literature.

METHODS

Toxicity of boron compounds was evaluated by using MTS analysis and obtained results were supported by morphological pictures, Trypan Blue staining and Annexin V staining. Additionally, the possible boron-related change in pluripotency of embryonic stem cells were analyzed with alkaline phosphatase activity and immunocytochemical staining of Oct4 protein as well as gene expression levels of pluripotency related OCT4, SOX2 and KLF4 genes. The alterations in the embryonic body formation capacity of mouse embryonic stem cells due to the application boron derivatives were also evaluated. Three linage differentiation was conducted to clarify the real impact of boron compounds on embryonic development. Lastly, cardiac differentiation of mESCs was investigated by using morphological pictures, cytosolic calcium measurement, gene expression and immunocytochemical analysis of cardiac differentiation related genes and in the presence of boron compounds.

RESULTS

Obtained results show that boron treatment maintains the pluripotency of embryonic stem cells at non-toxic concentrations. Additionally, endodermal, and mesodermal fate was found to be triggered after boron treatment. Also, initiation of cardiomyocyte differentiation by boron derivative treatments caused an increased gene expression levels of cardiac differentiation related TNNT2, Nkx2.5 and ISL-1 gene expression levels.

CONCLUSION

This study indicates that boron application, which is responsible for maintaining pluripotency of mESCs, can be used for increased cardiomyocyte differentiation of mESCs.

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. Previously, we showed these lines retain cellular and epigenetic characteristics of LPD and NPD embryos after several passages. Here, three main changes were identified in LPD ESC lines. First, their derivation capacity was reduced but pluripotency marker expression was similar to controls. Second, LPD lines had impaired Mitogen-activated protein kinase (MAPK) pathway with altered gene expression of several regulators (e.g., Maff, Rassf1, JunD), reduced ERK1/2 signalling capacity and poorer cell survival characteristics which may contribute to reduced derivation. Third, LPD lines had impaired glucose metabolism comprising reduced upstream enzyme expression (e.g., Gpi, Mpi) and accumulation of metabolites (e.g., glucose-6-P, fructose-6-P) above the phosphofructokinase (PFK) gateway with PFK enzyme activity reduced. ESC lines may therefore permit investigation of peri-conceptional programming mechanisms with reduced need for animal experimentation.

Graphical Abstract

Environmental Exposures around Conception: Developmental Pathways Leading to Lifetime Disease Risk

Environment around conception can influence the developmental programme with lasting effects on gestational and postnatal phenotype and with consequences for adult health and disease risk. Peri-conception exposure comprises a crucial part of the 'Developmental Origins of Health and Disease' (DOHaD) concept. In this review, we consider the effects of maternal undernutrition experienced during the peri-conception period in select human models and in a mouse experimental model of protein restriction. Human datasets indicate that macronutrient deprivation around conception affect the epigenome, with enduring effects on cardiometabolic and neurological health. The mouse model, comprising maternal low protein diet exclusively during the peri-conception period, has revealed a stepwise progression in altered developmental programming following induction through maternal metabolite deficiency. This progression includes differential effects in extra-embryonic and embryonic cell lineages and tissues, leading to maladaptation in the growth trajectory and increased chronic disease comorbidities. The timeline embraces an array of mechanisms across nutrient sensing and signalling, cellular, metabolic, epigenetic and physiological processes with a coordinating role for mTORC1 signalling proposed. Early embryos appear active participants in environmental sensing to optimise the developmental programme for survival but with the trade-off of later disease. Similar adverse health outcomes may derive from other peri-conception environmental experiences, including maternal overnutrition, micronutrient availability, pollutant exposure and assisted reproductive treatments (ART) and support the need for preconception health before pregnancy.