Search Results
You are looking at 1 - 6 of 6 items for
- Author: Pablo Bermejo-Álvarez x
- Refine by access: All content x
Search for other papers by Serafín Pérez-Cerezales in
Google Scholar
PubMed
Search for other papers by Priscila Ramos-Ibeas in
Google Scholar
PubMed
Search for other papers by Dimitrios Rizos in
Google Scholar
PubMed
Search for other papers by Pat Lonergan in
Google Scholar
PubMed
Search for other papers by Pablo Bermejo-Alvarez in
Google Scholar
PubMed
Search for other papers by Alfonso Gutiérrez-Adán in
Google Scholar
PubMed
Developmental plasticity enables the appearance of long-term effects in offspring caused by exposure to environmental stressors during embryonic and foetal life. These long-term effects can be traced to pre- and post-implantation development, and in both cases, the effects are usually sex specific. During preimplantation development, male and female embryos exhibit an extensive transcriptional dimorphism mainly driven by incomplete X chromosome inactivation. These early developmental stages are crucial for the establishment of epigenetic marks that will be conserved throughout development, making it a particularly susceptible period for the appearance of long-term epigenetic-based phenotypes. Later in development, gonadal formation generates hormonal differences between the sexes, and male and female placentae exhibit different responses to environmental stressors. The maternal environment, including hormones and environmental insults during pregnancy, contributes to sex-specific placental development that controls genetic and epigenetic programming during foetal development, regulating sex-specific differences, including sex-specific epigenetic responses to environmental hazards, leading to long-term effects. This review summarizes several human and animal studies examining sex-specific responses to environmental stressors during both the periconception period (caused by differences in sex chromosome dosage) and placental development (caused by both sex chromosomes and hormones). The identification of relevant sex-dependent trajectories caused by sex chromosomes and/or sex hormones is essential to define diagnostic markers and prevention/intervention protocols.
Search for other papers by Enrique Gómez in
Google Scholar
PubMed
Search for other papers by Alfonso Gutiérrez-Adán in
Google Scholar
PubMed
Search for other papers by Carmen Díez in
Google Scholar
PubMed
Search for other papers by Pablo Bermejo-Alvarez in
Google Scholar
PubMed
Search for other papers by Marta Muñoz in
Google Scholar
PubMed
Search for other papers by Aida Rodriguez in
Google Scholar
PubMed
Search for other papers by Jesús Otero in
Google Scholar
PubMed
Search for other papers by María Alvarez-Viejo in
Google Scholar
PubMed
Search for other papers by David Martín in
Google Scholar
PubMed
Search for other papers by Susana Carrocera in
Google Scholar
PubMed
Search for other papers by José Néstor Caamaño in
Google Scholar
PubMed
Parthenotes may represent an alternate ethical source of stem cells, once biological differences between parthenotes and embryos can be understood. In this study, we analyzed development, trophectoderm (TE) differentiation, apoptosis/necrosis, and ploidy in parthenotes and in vitro produced bovine embryos. Subsequently, using real-time PCR, we analyzed the expression of genes expected to underlie the observed differences at the blastocyst stage. In vitro matured oocytes were either fertilized or activated with ionomycin +6-DMAP and cultured in simple medium. Parthenotes showed enhanced blastocyst development and diploidy and reduced TE cell counts. Apoptotic and necrotic indexes did not vary, but parthenotes evidenced a higher relative proportion of apoptotic cells between inner cell mass and TE. The pluripotence-related POU5F1 and the methylation DNMT3A genes were downregulated in parthenotes. Among pregnancy recognition genes, TP-1 was upregulated in parthenotes, while PGRMC1 and PLAC8 did not change. Expression of p66 shc and BAX/BCL2 ratio were higher, and p53 lower, in parthenotes. Among metabolism genes, SLC2A1 was downregulated, while AKR1B1, PTGS2, H6PD, and TXN were upregulated in parthenotes, and SLC2A5 did not differ. Among genes involved in compaction/blastulation, GJA1 was downregulated in parthenotes, but no differences were detected within ATP1A1 and CDH1. Within parthenotes, the expression levels of SLC2A1, TP-1, and H6PD, and possibly AKR1B1, resemble patterns described in female embryos. The pro-apoptotic profile is more pronounced in parthenotes than in embryos, which may differ in their way to channel apoptotic stimuli, through p66 shc and p53 respectively, and in their mechanisms to control pluripotency and de novo methylation.
Search for other papers by Priscila Ramos-Ibeas in
Google Scholar
PubMed
Search for other papers by Ismael Lamas-Toranzo in
Google Scholar
PubMed
Search for other papers by Álvaro Martínez-Moro in
Google Scholar
PubMed
Search for other papers by Celia de Frutos in
Google Scholar
PubMed
Search for other papers by Alejandra C Quiroga in
Google Scholar
PubMed
Search for other papers by Esther Zurita in
Google Scholar
PubMed
Search for other papers by Pablo Bermejo-Álvarez in
Google Scholar
PubMed
Failures during conceptus elongation are a major cause of pregnancy losses in ungulates, exerting a relevant economic impact on farming. The developmental events occurring during this period are poorly understood, mainly because this process cannot be recapitulated in vitro. Previous studies have established an in vitro post-hatching development (PHD) system that supports bovine embryo development beyond the blastocyst stage, based on agarose gel tunnels and serum- and glucose-enriched medium. Unfortunately, under this system embryonic disc formation is not achieved and embryos show notorious signs of apoptosis and necrosis. The objective of this study has been to develop an in vitro system able to support embryonic disc formation. We first compared post-hatching development inside agarose tunnels or free-floating over an agarose-coated dish in serum- and glucose-enriched medium (PHD medium). Culture inside agarose tunnels shaped embryo morphology by physical constriction, but it restricted embryo growth and did not provide any significant advantage in terms of development of hypoblast and epiblast lineages. In contrast to PHD medium, a chemically defined and enriched medium (N2B27) supported complete hypoblast migration and epiblast survival in vitro, even in the absence of agarose coating. Cells expressing the pluripotency marker SOX2 were observed in ~56% of the embryos and ~25% developed embryonic disc-like structures formed by SOX2+ cells. In summary, here we provide a culture system that supports trophectoderm proliferation, hypoblast migration and epiblast survival after the blastocyst stage.
Search for other papers by Ricaurte Lopera-Vasquez in
Google Scholar
PubMed
Search for other papers by Meriem Hamdi in
Google Scholar
PubMed
Search for other papers by Veronica Maillo in
Google Scholar
PubMed
Search for other papers by Alfonso Gutierrez-Adan in
Google Scholar
PubMed
Search for other papers by Pablo Bermejo-Alvarez in
Google Scholar
PubMed
Search for other papers by Miguel Ángel Ramírez in
Google Scholar
PubMed
Departamento de Biologia Molecular, UAM/CBM-SO, Madrid, Spain
Search for other papers by María Yáñez-Mó in
Google Scholar
PubMed
Search for other papers by Dimitrios Rizos in
Google Scholar
PubMed
The aim of this study was to evaluate the effect of extracellular vesicles (EV) from oviductal fluid (OF), either from the ampulla or isthmus, on the development and quality of in vitro-cultured bovine embryos. Zygotes were cultured in synthetic oviduct fluid (SOF + 3 mg/mL BSA) without calf serum (C− group), in the presence of 3 × 105 EV/mL from ampullary or isthmic OF at either 1 × 104 g (10 K) or 1 × 105 g (100 K), and compared with SOF + 5% FCS (C+ group). OF-EV size and concentration were assessed by electron microscopy and nanotracking analysis system. Embryo development was recorded on Days 7–9, and blastocyst quality was assessed through cryotolerance and gene expression analysis. Lower blastocyst yield was observed on Day 7 in the C− and OF-EV groups (12.0–14.3%) compared with C+ (20.6%); however, these differences were compensated at Days 8 and 9 (Day 9: 28.5–30.8%). Importantly, the survival rate of blastocysts produced with isthmic 100 K OF-EV was higher than that of C+ and C− group at 72 h after vitrification and warming (80.1 vs 34.5 and 50.5% respectively, P < 0.05). In terms of gene expression, blastocysts produced in the presence of 100 K isthmic OF-EV upregulated the water channel AQP3 and DNMT3A and SNRPN transcripts compared with the C+, with the expression in C− being intermediate. The lipid receptor LDLR was downregulated in C+ compared with all other groups. In conclusion, the addition of oviductal fluid extracellular vesicles from isthmus, to in vitro culture of bovine embryos in the absence of serum improves the development and quality of the embryos produced.
Search for other papers by Nuria Martínez de los Reyes in
Google Scholar
PubMed
Search for other papers by Inés Flores-Borobia in
Google Scholar
PubMed
Search for other papers by Melissa Carvajal-Serna in
Google Scholar
PubMed
Search for other papers by Pilar Marigorta in
Google Scholar
PubMed
Search for other papers by Pablo Bermejo-Álvarez in
Google Scholar
PubMed
Search for other papers by Priscila Ramos-Ibeas in
Google Scholar
PubMed
In brief
MEK signalling pathway is required for hypoblast differentiation in mouse embryos, but its role in ungulate embryos remains controversial. This paper demonstrates that MEK is required for hypoblast specification in the inner cell mass of the ovine blastocyst and that it plays a role during the hypoblast migration occurring following blastocyst hatching.
Abstract
Early embryo development requires the differentiation of three cell lineages in two differentiation events. The second lineage specification differentiates the inner cell mass into epiblast, which will form the proper fetus, and hypoblast, which together with the trophectoderm will form the extraembryonic membranes and the fetal part of the placenta. MEK signalling pathway is required for hypoblast differentiation in mouse embryos, but its role in ungulate embryos remains controversial. The aim of this work was to analyse the role of MEK signalling on hypoblast specification at the blastocyst stage and on hypoblast migration during post-hatching stages in vitro in the ovine species. Using well-characterized and reliable lineage markers, and different MEK inhibitor concentrations, we demonstrate that MEK signalling pathway is required for hypoblast specification in the inner cell mass of the ovine blastocyst, and that it plays a role during the hypoblast migration occurring following blastocyst hatching. These results show that the role of MEK signalling pathway on hypoblast specification is conserved in phylogenetically distant mammals.
Search for other papers by Pérez-Gómez Alba in
Google Scholar
PubMed
Search for other papers by Flores-Borobia Inés in
Google Scholar
PubMed
Department of Cell Biology and Histology, Universidad de Murcia. International Excellence Campus for Higher Education and Research (Campus Mare Nostrum), Murcia, Spain
Search for other papers by Hamze Julieta Gabriela in
Google Scholar
PubMed
Search for other papers by Galiano-Cogolludo Beatriz in
Google Scholar
PubMed
Search for other papers by Lamas-Toranzo Ismael in
Google Scholar
PubMed
Search for other papers by González-Brusi Leopoldo in
Google Scholar
PubMed
Search for other papers by Ramos-Ibeas Priscila in
Google Scholar
PubMed
Search for other papers by Bermejo-Álvarez Pablo in
Google Scholar
PubMed
In brief
Bovine embryos lacking SMC2 (a core component of condensins I and II) are unable to survive maternal recognition of pregnancy. SMC2 KO embryos are able to form blastocysts, exhibiting a reduced cell proliferation ability, and arrest their development shortly after hatching.
Abstract
Condensins are large protein complexes required for chromosome assembly and segregation during mitosis and meiosis. Mouse or bovine embryos lacking SMC2 (a core component of condensins I and II) do not complete development to term, but it is unknown when they arrest their development. Herein, we have assessed the developmental ability of bovine embryos lacking SMC2 due to a naturally occurring mutation termed HH3 (Holstein Haplotype 3) or by CRISPR-mediated gene ablation. To determine if embryos homozygous for the HH3 allele survive to maternal recognition of pregnancy, embryonic day (E)14 embryos were flushed from superovulated carrier cows inseminated with a carrier bull. Mendelian inheritance of the HH3 allele was observed at E14 conceptuses but conceptuses homozygous for HH3 failed to achieve elongation and lacked an embryonic disc. To assess the consequence of the ablation of condensins I and II at earlier developmental stages, SMC2 KO bovine embryos were generated in vitro using CRISPR technology. SMC2 KO embryos were able to form blastocysts but exhibited reduced cell proliferation as evidenced by a significantly lower number of total, trophectoderm (CDX2+), and inner cell mass (SOX2+) cells at Day (D) 8 post-fertilization compared to their WT counterparts and were unable to survive to D12 in vitro. SMC2 ablation did not alter relative telomere length at D8, D12, or E14. In conclusion, condensins I and II are required for blastomere mitosis during early development, and embryos lacking those complexes arrest their development shortly after blastocyst hatching.
