Chromosome segregation in female germ cells and early embryonic blastomeres is known to be highly prone to errors. The resulting aneuploidy is therefore the most frequent cause of termination of early development and embryo loss in mammals. And in specific cases, when the aneuploidy is actually compatible with embryonic and fetal development, it leads to severe developmental disorders. The main surveillance mechanism, which is essential for the fidelity of chromosome segregation, is the Spindle Assembly Checkpoint (SAC). And although all eukaryotic cells carry genes required for SAC, it is not clear whether this pathway is active in all cell types, including blastomeres of early embryos. In this review, we will summarize and discuss the recent progress in our understanding of the mechanisms controlling chromosome segregation and how they might work in embryos and mammalian embryos in particular. Our conclusion from the current literature is that the early mammalian embryos show limited capabilities to react to chromosome segregation defects, which might, at least partially, explain the widespread problem of aneuploidy during the early development in mammals.
- MeSH
- aneuploidie MeSH
- chromozomy MeSH
- embryonální vývoj * genetika MeSH
- lidé MeSH
- savci genetika MeSH
- segregace chromozomů * MeSH
- velikost buňky MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- MeSH
- dýchací soustava * embryologie MeSH
- embryonální vývoj fyziologie MeSH
- lidé MeSH
- organogeneze fyziologie MeSH
- plicní surfaktanty MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
FTO and ALKBH5 proteins are essential erasers of N6-adenosine methylation in RNA. We studied how levels of FTO and ALKBH5 proteins changed during mouse embryonic development, aging, cardiomyogenesis, and neuroectodermal differentiation. We observed that aging in male and female mice was associated with FTO up-regulation in mouse hearts, brains, lungs, and kidneys, while the ALKBH5 level remained stable. FTO and ALKBH5 proteins were up-regulated during experimentally induced cardiomyogenesis, but the level of ALKBH5 protein was not changed when neuroectodermal differentiation was induced. HDAC1 depletion in mouse ES cells caused FTO down-regulation. In these cells, mRNA, carrying information from genes that regulate histone signature, RNA processing, and cell differentiation, was characterized by a reduced level of N6-adenosine methylation in specific gene loci, primarily regulating cell differentiation into neuroectoderm. Together, when we compared both RNA demethylating proteins, the FTO protein level undergoes the most significant changes during cell differentiation and aging. Thus, we conclude that during aging and neuronal differentiation, m6A RNA demethylation is likely regulated by the FTO protein but not via the function of ALKBH5.
- MeSH
- adenosin metabolismus MeSH
- alfa-ketoglutarát-dependentní dioxygenasa, AlkB homolog 5 * genetika metabolismus MeSH
- buněčná diferenciace MeSH
- embryonální vývoj MeSH
- gen pro FTO * genetika metabolismus MeSH
- myši MeSH
- RNA metabolismus MeSH
- stárnutí genetika MeSH
- upregulace MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The cell body space occupied by the nucleus decreased during the cell differentiation of the granulocytic cell lineage in CML (Chronic Myeloid Leukemia) patients. In contrary, in patients suffering from CLL (Chronic Lymphocytic Leukemia), the cell body space occupied by the nucleus during the cell differentiation of the lymphocytic lineage did not decrease despite the reduction of the cell size. Thus, the cell body space occupied by the cell nucleus during the differentiation was characteristic for each of these cell lineages.
- MeSH
- buněčná diferenciace MeSH
- buněčný rodokmen MeSH
- chronická lymfatická leukemie * MeSH
- lidé MeSH
- retrospektivní studie MeSH
- tělo buňky * MeSH
- velikost buněčného jádra MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Cells of pre-implantation embryos are equipped with many morphological and functional systems through which they can synthesize specific proteins and effectively ensure the protection of early embryonic development. Here we present evidence for the existence of these systems in morphologically normal and abnormal bovine blastocyst stage embryos in vivo at the ultrastructural and actin cytoskeleton levels. The appearance of organelles in the trophectoderm (TE) and inner cell mass (ICM) cells, responsible for their synthetic activities and their role in the development of early bovine embryos are described. We point out the importance of endocytic processes and the participation of extracellular vesicles in the formation of intercellular contacts and homeostasis of the embryo microenvironment. Several changes in the ultrastructural morphology of embryos produced by different methods (ICSI, parthenogenetic AC/DC electrical activation, IVF with separated sperm) and freezing/thawed embryos are described. We also show alterations occurred in the organelles after viral contamination of embryos with BHV-1 and BVDV viruses, and in embryos from over-conditioned cows. Recorded changes in organelles and appearance of cellular autophagic structures (vesicles, multivesicular bodies and autophagolysosomes) may negatively affect embryo metabolism and lead to the emergence of pathological processes in TE and ICM cells of preimplantation embryos.
- MeSH
- blastocysta fyziologie ultrastruktura MeSH
- embryonální vývoj * fyziologie MeSH
- skot MeSH
- sperma * MeSH
- těhotenství MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- skot MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
Healing of dense regular connective tissue, due to a high fiber-to-cell ratio and low metabolic activity and regeneration potential, frequently requires surgical implantation or reconstruction with high risk of reinjury. An alternative to synthetic implants is using bioscaffolds obtained through decellularization, a process where the aim is to extract cells from the tissue while preserving the tissue-specific native molecular structure of the ECM. Proteins, lipids, nucleic acids and other various extracellular molecules are largely involved in differentiation, proliferation, vascularization and collagen fibers deposit, making them the crucial processes in tissue regeneration. Because of the multiple possible forms of cell extraction, there is no standardized protocol in dense regular connective tissue (DRCT). Many modifications of the structure, shape and composition of the bioscaffold have also been described to improve the therapeutic result following the implantation of decellularized connective tissue. The available data provide a valuable source of crucial information. However, the wide spectrum of decellularization makes it important to understand the key aspects of bioscaffolds relative to their potential use in tissue regeneration.
- Klíčová slova
- zygotic splitting,
- MeSH
- dvojčata monozygotní MeSH
- fertilizace in vitro metody MeSH
- gravidita MeSH
- incidence MeSH
- lidé MeSH
- přenos embrya metody přístrojové vybavení MeSH
- rozdělení zygoty MeSH
- těhotenství mnohočetné * statistika a číselné údaje MeSH
- Check Tag
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
Preimplantation mouse embryo development involves temporal-spatial specification and segregation of three blastocyst cell lineages: trophectoderm, primitive endoderm and epiblast. Spatial separation of the outer-trophectoderm lineage from the two other inner-cell-mass (ICM) lineages starts with the 8- to 16-cell transition and concludes at the 32-cell stages. Accordingly, the ICM is derived from primary and secondary contributed cells; with debated relative EPI versus PrE potencies. We report generation of primary but not secondary ICM populations is highly dependent on temporal activation of mammalian target of Rapamycin (mTOR) during 8-cell stage M-phase entry, mediated via regulation of the 7-methylguanosine-cap (m7G-cap)-binding initiation complex (EIF4F) and linked to translation of mRNAs containing 5' UTR terminal oligopyrimidine (TOP-) sequence motifs, as knockdown of identified TOP-like motif transcripts impairs generation of primary ICM founders. However, mTOR inhibition-induced ICM cell number deficits in early blastocysts can be compensated by the late blastocyst stage, after inhibitor withdrawal; compensation likely initiated at the 32-cell stage when supernumerary outer cells exhibit molecular characteristics of inner cells. These data identify a novel mechanism specifically governing initial spatial segregation of mouse embryo blastomeres, that is distinct from those directing subsequent inner cell formation, contributing to germane segregation of late blastocyst lineages.
- MeSH
- embryonální vývoj MeSH
- lidé MeSH
- urogenitální abnormality MeSH
- urogenitální systém * embryologie MeSH
- vývoj plodu * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
Príspevok popisuje vplyv prenatálnej expozície alkoholu (PAE) v kontexte vzniku kraniofaciálnych a ostatných typických deficitov u detí s fetálnym alkoholovým syndrómom – FAS. FAS je najzávažnejšou diagnózou porúch fetálneho alkoholového spektra – FASD. FASD je nediagnostický súhrnný termín pre možné následky PAE. Ide o súbor anatomických malformácií a neurovývinových abnormalít vzniknutých počas vnútromaternicového vývinu jednotlivca konzumáciou alkoholu matkou počas tehotenstva. V rámci diagnostiky FASD, vrátane FAS, existuje celosvetovo viacero diagnostických manuálov. Na Slovensku sa zatiaľ používa The 4-Digit Code podľa Astley (2004). Daný manuál má veľmi dobre prepracovanú časť diagnostiky kraniofaciálnych deficitov. Pri FAS sú typickými znakmi na tvári tzv. sentinelové črty tváre. Patria sem krátka viečková štrbina, úzka horná pera a vyhladená ryha medzi nosom a hornou perou. Z hľadiska logopédie je dôležité vedieť aj o anomáliách vývinu zubov, pier, podnebia, nosa, uší a očí. V rámci etiogenézy kraniofaciálnych a ostatných typických deficitov sa vo všeobecnosti uvádzajú molekulárne, biochemické, bunkové a embryonálne mechanizmy.
The article describes the impact of prenatal alcohol exposure (PAE) in the context of the development of craniofacial and other typical deficits in children with foetal alcohol syndrome - FAS. FAS is the most serious diagnosis of foetal alcohol spectrum disorders - FASD. FASD is a non-diagnostic umbrella term for possible consequences of PAE. It is a set of anatomical malformations and neurodevelopmental abnormalities created during intrauterine development of an individual due to alcohol consumption by the mother during pregnancy. There are several diagnostic manuals worldwide for the diagnosis of FASD, including FAS. The 4-Digit Code according to Astley (2004) is currently used in Slovakia. The given manual has a very well-researched section on the diagnosis of craniofacial deficits. In FAS, the typical signs on the face are what are called the sentinel facial features. These include a short palpebral fissure, a narrow upper lip, and a smooth crease between the nose and the upper lip. From the point of view of Speech Therapy, it is also important to know about anomalies in the development of the teeth, lips, palate, nose, ears and eyes. As part of the aetiology of craniofacial and other typical deficits, molecular, biochemical, cellular and embryonic mechanisms are generally mentioned.
