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Preimplantation embryo

Masami Hayashi, Kayo Yoshida, Kohei Kitada, Akane Kizu, Daisuke Tachibana, Mitsuru Fukui, Takashi Morita, Masayasu Koyama
PURPOSE: To study the outcomes of mouse preimplantation embryos irradiated with low doses of X-rays (≤ 1 Gy) and investigate apoptosis and pluripotency of the irradiated embryos. METHODS: Mouse embryos at the 2-cell stage were collected for in vitro culture. After reaching the 8-cell stage, embryos were irradiated with various low doses of X-rays (0-1 Gy). Blastocysts with a normal appearance were transferred into a pseudopregnant uterus. The developmental rate to blastocysts and the survival rate following embryo transfer were examined...
March 16, 2018: Journal of Assisted Reproduction and Genetics
Te-Sha Tsai, Sonika Tyagi, Justin C St John
STUDY QUESTION: What are the molecular differences between mitochondrial DNA (mtDNA)-deficient and mtDNA-normal oocytes and how does mitochondrial supplementation alter these? SUMMARY ANSWER: Changes to DNA methylation in a 5' cytosine-phosphate-guanine 3' (CpG) island in the mtDNA-specific replication factor (DNA polymerase gamma (POLG)) of mtDNA-deficient oocytes mediates an increase in mtDNA copy number by the 2-cell stage that positively modulates the expression of nuclear genes, which affect cellular and metabolic processes, following autologous mitochondrial supplementation...
March 13, 2018: Human Reproduction
M Irani, N Zaninovic, C Canon, C O'Neill, V Gunnala, Q Zhan, G Palermo, D Reichman, Z Rosenwaks
STUDY QUESTION: Is there a benefit to assessing ploidy in delayed embryos reaching the morula stage on Day 6 of development? SUMMARY ANSWER: Day-6 morulae should be considered for biopsy in women <40 years old undergoing preimplantation genetic testing for aneuploidy (PGT-A) because they are associated with acceptable, albeit reduced, euploidy and implantation rates (IRs). WHAT IS KNOWN ALREADY: Embryo development and morphology have been shown to correlate with aneuploidy and pregnancy rates...
March 13, 2018: Human Reproduction
Qingqing Wei, Ruiqi Li, Liang Zhong, Haiyuan Mu, Shaopeng Zhang, Liang Yue, Jinzhu Xiang, Enhong Li, Minglei Zhi, Suying Cao, Jianyong Han
After zygotic genome activation and lineage specification, zygotes develop into late blastocysts comprising three distinct cell types. The molecular mechanisms underlying this progress are largely unknown in pigs. Here, we intended to analyze an extensive set of regulators at the single-cell level to define the events involved in the development of the porcine blastocysts. Using a quantitative microfluidics approach in single cells, we detected mRNA levels of 96 genes known to function in early embryonic development and maintenance of stem cell pluripotency simultaneously in 480 individual cells derived from porcine preimplantation embryos...
March 13, 2018: Biology of Reproduction
Laura Masala, Federica Ariu, Luisa Bogliolo, Emanuela Bellu, Sergio Ledda, Daniela Bebbere
Oocytes from prepubertal animals have a reduced ability to undergo embryo development and produce viable offspring. The present work used an ovine model consisting of oocytes derived from adult and prepubertal donors to assess the molecular status of oocytes and preimplantation embryos with different developmental competence. The lower potential of oocytes of young donors was confirmed in terms of in vitro developmental capabilities and kinetics. A panel of genes including maternal effect (DPPA3, GDF9, NMP2, ZAR1) and housekeeping genes (ACTB, RPL19, SDHA, YWHAZ, ATP1A1), genes involved in DNA methylation (DNMT1, DNMT3A, DNMT3B), genomic imprinting (IGF2R), pluripotency (NANOG, POU5F1) and cell cycle regulation (CCNB1, CDK1, MELK) was relatively quantified...
March 15, 2018: Molecular Reproduction and Development
Verónica M Negrón-Pérez, Luana Teixeira Rodrigues, Gisele Zoccal Mingoti, Peter J Hansen
Rho-associated coiled-coil containing protein kinases (ROCK1 and ROCK2) are activated by binding to RHO GTPases and phosphorylate a variety of downstream targets including actinomyosin. In the mouse embryo, ROCK signaling acts to promote formation of trophectoderm (TE) and inhibit formation of the inner cell mass (ICM) by polarizing outer cells of the embryo to inactivate Hippo signaling (Kono et al., 2014; Mihajlović and Bruce, 2016). This article is protected by copyright. All rights reserved.
March 15, 2018: Molecular Reproduction and Development
Yan Hao, Dawei Chen, Zhiguo Zhang, Ping Zhou, Yunxia Cao, Zhaolian Wei, Xiaofeng Xu, Beili Chen, Weiwei Zou, Mingrong Lv, Dongmei Ji, Xiaojin He
Hearing loss may place a heavy burden on the patient and patient's family. Given the high incidence of hearing loss among newborns and the huge cost of treatment and care (including cochlear implantation), prenatal diagnosis is strongly recommended. Termination of the fetus may be considered as an extreme outcome to the discovery of a potential deaf fetus, and therefore preimplantation genetic diagnosis has become an important option for avoiding the birth of affected children without facing the risk of abortion following prenatal diagnosis...
April 2018: Oncology Letters
Michael W Pankhurst, Rebecca L Kelley, Rachel L Sanders, Savana R Woodcock, Dorothy E Oorschot, Nicola J Batchelor
Anti-Müllerian hormone (AMH) is an ovarian regulator that affects folliculogenesis. AMH inhibits the developmental activation of the dormant primordial follicles and the oocyte within. In more mature follicles, AMH reduces granulosa cell sensitivity to follicle-stimulating hormone (FSH). We examined the effects of AMH overexpression on the stages of ovarian folliculogenesis, and the development of embryos, with a transgenic mouse that overexpresses human AMH in central nervous system neurons under the control of the mouse Thy1...
March 14, 2018: Journal of Endocrinology
Joshua Shaw
This essay considers one argument used to defend parents who use preimplantation genetic diagnosis (PGD) to select for deafness and other disabilities. Some bioethicists have argued that a distinction should be drawn between genetically modifying embryos to possess disabilities and using PGD to select embryos that already present markers of them, and that the former is unethical because it inflicts avoidable harms onto the resulting children, whereas the latter is permissible because it allows children with potentially impaired abilities to exist...
April 2018: New Bioethics: a Multidisciplinary Journal of Biotechnology and the Body
Erkan Gumus, Ismail Sari, Meral Yilmaz, Ali Cetin
Improving the success of in vitro fertilization (IVF) and infertility treatment depend on understanding basic cellular and molecular mechanisms of human preimplantation development. Pre-implantation mouse embryo model is an ideal empiric system to understand these mechanisms. This study was aimed to investigate the gene and protein expressions of LAMTOR1 in mouse oocytes and pre-implantation embryos at different developmental stages. The findings demonstrate that LAMTOR1 was detected in the oocytes and in subsequent all stages of embryo development...
March 3, 2018: Gene Expression Patterns: GEP
Zohreh Zare, Beheshteh Abouhamzeh, Reza Masteri Farahani, Mohammad Salehi, Moslem Mohammadi
Background: Oocyte developmental competence is one of the key factors for determining the success rate of assisted reproductive technique. Objective: The aim of the current study was to investigate the effect of L-carnitine (LC) supplementation during in vitro maturation (IVM), on preimplantation embryo development and expression of genes involved in embryo competence derived from oocytes selected with brilliant cresyl blue (BCB) test. Materials and Methods: Cumulus-oocyte complexes (COCs) were obtained from NMRI mice ovaries...
December 2017: International Journal of Reproductive Biomedicine (Yazd, Iran)
Tapan Kumar Mistri, Wibowo Arindrarto, Wei Ping Ng, Choayang Wang, Leng Hiong Lim, Lili Sun, Ian Chambers, Thorsten Wohland, Paul Robson
Oct4 and Sox2 regulate the expression of target genes such as Nanog, Fgf4 and Utf1 , by binding to their respective regulatory motifs. Their functional cooperation is reflected in their ability to heterodimerise on adjacent cis regulatory motifs, the composite Sox/Oct motif. Given that Oct4 and Sox2 regulate many developmental genes, a quantitative analysis of their synergistic action on different Sox/Oct motifs would yield valuable insights into the mechanisms of early embryonic development. In this study, we measured binding affinities of Oct4 and Sox2 to different Sox/Oct motifs using fluorescence correlation spectroscopy (FCS)...
February 27, 2018: Biochemical Journal
Kilian Simmet, Valeri Zakhartchenko, Julia Philippou-Massier, Helmut Blum, Nikolai Klymiuk, Eckhard Wolf
Mammalian preimplantation development involves two lineage specifications: first, the CDX2-expressing trophectoderm (TE) and a pluripotent inner cell mass (ICM) are separated during blastocyst formation. Second, the pluripotent epiblast (EPI; expressing NANOG) and the differentiated primitive endoderm (PrE; expressing GATA6) diverge within the ICM. Studies in mice revealed that OCT4/POU5F1 is at the center of a pluripotency regulatory network. To study the role of OCT4 in bovine preimplantation development, we generated OCT4 knockout (KO) fibroblasts by CRISPR-Cas9 and produced embryos by somatic cell nuclear transfer (SCNT)...
February 26, 2018: Proceedings of the National Academy of Sciences of the United States of America
Sergio Menchero, Julio Sainz de Aja, Miguel Manzanares
The trophectoderm (TE) is the first cell population to appear in the mammalian preimplantation embryo, as the result of the differentiation of totipotent blastomeres located on the outer surface of the late morula. Trophectodermal cells arrange in a monolayer covering the expanding blastocyst and acquire an epithelial phenotype with distinct apicobasal polarity and a basal lamina placed toward the blastocyst interior. During later development through the periimplantation and gastrulation stages, the TE gives rise to extraembryonic membranes and cell types that will eventually form most of the fetal placenta, the specialized organ through which the embryo obtains maternal nourishment necessary for subsequent exponential growth...
2018: Current Topics in Developmental Biology
Stephanie Bissiere, Maxime Gasnier, Yanina D Alvarez, Nicolas Plachta
The early mouse embryo offers a phenomenal system to dissect how changes in the mechanisms controlling cell fate are integrated with morphogenetic events at the single-cell level. New technologies based on live imaging have enabled the discovery of dynamic changes in the regulation of single genes, transcription factors, and epigenetic mechanisms directing early cell fate decision in the early embryo. Here, we review recent progress in linking molecular dynamic events occurring at the level of the single cell in vivo, to some of the key morphogenetic changes regulating early mouse development...
2018: Current Topics in Developmental Biology
Sissy E Wamaitha, Kathy K Niakan
Understanding the progression of early human embryonic development prior to implantation is of fundamental biological importance. Greater insights into early developmental events may lead to clinical improvements, not only via the establishment of novel stem cell models with increased potential or more physiological relevance, but also by uncovering some underlying causes of infertility, miscarriages, and developmental disorders. The majority of human embryos available for study are those donated to research once they are surplus to family building following in vitro fertilization, though in some countries it is also possible to create embryos using donated gametes...
2018: Current Topics in Developmental Biology
Michelle K Y Seah, Daniel M Messerschmidt
When reflecting about cell fate commitment we think of differentiation. Be it during embryonic development or in an adult stem cell niche, where cells of a higher potency specialize and cell fate decisions are taken. Under normal circumstances this process is definitive and irreversible. Cell fate commitment is achieved by the establishment of cell-type-specific transcriptional programmes, which in turn are guided, reinforced, and ultimately locked-in by epigenetic mechanisms. Yet, this plunging drift in cellular potency linked to epigenetically restricted access to genomic information is problematic for reproduction...
2018: Current Topics in Developmental Biology
Priscila Ramos-Ibeas, Jennifer Nichols, Ramiro Alberio
Mouse embryonic stem cells (ESC), derived from preimplantation embryos in 1981, defined mammalian pluripotency for many decades. However, after the derivation of human ESC in 1998, comparative studies showed that different types of pluripotency exist in early embryos and that these can be captured in vitro under various culture conditions. Over the past decade much has been learned about the key signaling pathways, growth factor requirements, and transcription factor profiles of pluripotent cells in embryos, allowing improvement of derivation and culture conditions for novel pluripotent stem cell types...
2018: Current Topics in Developmental Biology
Deepak Saini, Yojiro Yamanaka
During the first few days in the mouse preimplantation embryo, two types of cells, polar and apolar cells are generated from spherical totipotent blastomeres. Sequential morphogenetic events, polarization, compaction, and asymmetric division, are essential for the generation of the first distinct cell populations, polar and apolar cells, which establish the outer/inner configuration within the embryo. This leads to position-dependent activation of the Hippo signaling pathway and lineage-specific gene expression to form the trophectoderm and inner cell mass in a blastocyst...
2018: Current Topics in Developmental Biology
Takayuki Tatsumi, Kaori Takayama, Shunsuke Ishii, Atsushi Yamamoto, Taichi Hara, Naojiro Minami, Naoyuki Miyasaka, Toshiro Kubota, Akira Matsuura, Eisuke Itakura, Satoshi Tsukamoto
Although autophagy is classically viewed as a non-selective degradation system, recent studies have revealed that various forms of selective autophagy also play crucial physiological roles. However, the induction of selective autophagy is not well understood. In this study, we established a forced selective autophagy system using a fusion of an autophagy adaptor and a substrate-binding protein. In both mammalian cells and fertilized mouse embryos, efficient forced lipophagy was induced by expression of a fusion of p62 (Sqstm1) and a lipid droplet (LD)-binding domain...
February 23, 2018: Development
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