Sphingolipids (SLs) are important signaling molecules and functional components of cellular membranes. Although SLs are known as crucial regulators of neural cell physiology and differentiation, modulations of SLs by environmental neurotoxicants in neural cells and their neuronal progeny have not yet been explored. In this study, we used in vitro models of differentiated neuron-like cells, which were repeatedly exposed during differentiation to model environmental toxicants, and we analyzed changes in sphingolipidome, cellular morphology and gene expression related to SL metabolism or neuronal differentiation. We compared these data with the results obtained in undifferentiated neural cells with progenitor-like features. As model polychlorinated organic pollutants, we used 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3'-dichlorobiphenyl (PCB11) and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB153). PCB153 revealed itself as the most prominent deregulator of SL metabolism and as potent toxicant during early phases of in vitro neurogenesis. TCDD exerted only minor changes in the levels of analysed lipid species, however, it significantly changed the rate of pro-neuronal differentiation and deregulated expression of neuronal markers during neurogenesis. PCB11 acted as a potent disruptor of in vitro neurogenesis, which induced significant alterations in SL metabolism and cellular morphology in both differentiated neuron-like models (differentiated NE4C and NG108-15 cells). We identified ceramide-1-phosphate, lactosylceramides and several glycosphingolipids to be the most sensitive SL species to exposure to polychlorinated pollutants. Additionally, we identified deregulation of several genes related to SL metabolism, which may be explored in future as potential markers of developmental neurotoxicity.
- MeSH
- buněčná diferenciace účinky léků MeSH
- buněčné linie MeSH
- látky znečišťující životní prostředí toxicita MeSH
- neurogeneze účinky léků MeSH
- neurony účinky léků metabolismus MeSH
- neurotoxické syndromy etiologie genetika MeSH
- polychlorované bifenyly farmakologie toxicita MeSH
- polychlorované dibenzodioxiny toxicita MeSH
- sfingolipidy metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Embryonic neural stem cells (NSCs), comprising neuroepithelial and radial glial cells, are indispensable precursors of neurons and glia in the mammalian developing brain. Since the process of neurogenesis occurs in a hypoxic environment, the question arises of how NSCs deal with low oxygen tension and whether it affects their stemness. Genes from the hypoxia-inducible factors (HIF) family are well known factors governing cellular response to hypoxic conditions. In this study, we have discovered that the endogenous stabilization of hypoxia-inducible factor 1α (Hif1α) during neural induction is critical for the normal development of the NSCs pool by preventing its premature depletion and differentiation. The knock-out of the Hif1α gene in mESC-derived neurospheres led to a decrease in self-renewal of NSCs, paralleled by an increase in neuronal differentiation. Similarly, neuroepithelial cells differentiated in hypoxia exhibited accelerated neurogenesis soon after Hif1α knock-down. In both models, the loss of Hif1α was accompanied by an immediate drop in neural repressor Hes1 levels while changes in Notch signaling were not observed. We found that active Hif1α/Arnt1 transcription complex bound to the evolutionarily conserved site in Hes1 gene promoter in both neuroepithelial cells and neural tissue of E8.5 - 9.5 embryos. Taken together, these results emphasize the novel role of Hif1α in the regulation of early NSCs population through the activation of neural repressor Hes1, independently of Notch signaling.
- MeSH
- buněčná diferenciace MeSH
- buněčné linie MeSH
- hypoxie MeSH
- nervové kmenové buňky * MeSH
- neurogeneze MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Development of neural tube has been extensively modeled in vitro using human pluripotent stem cells (hPSCs) that are able to form radially organized cellular structures called neural rosettes. While a great amount of research has been done using neural rosettes, studies have only inadequately addressed how rosettes are formed and what the molecular mechanisms and pathways involved in their formation are. Here we address this question by detailed analysis of the expression of pluripotency and differentiation-associated proteins during the early onset of differentiation of hPSCs towards neural rosettes. Additionally, we show that the BMP signaling is likely contributing to the formation of the complex cluster of neural rosettes and its inhibition leads to the altered expression of PAX6, SOX2 and SOX1 proteins and the rosette morphology. Finally, we provide evidence that the mechanism of neural rosettes formation in vitro is reminiscent of the process of secondary neurulation rather than that of primary neurulation in vivo. Since secondary neurulation is a largely unexplored process, its understanding will ultimately assist the development of methods to prevent caudal neural tube defects in humans.
- MeSH
- buněčná diferenciace * MeSH
- COUP transkripční faktor II genetika metabolismus MeSH
- faktory domény POU genetika metabolismus MeSH
- homeodoménové proteiny genetika metabolismus MeSH
- kultivované buňky MeSH
- lidé MeSH
- nervové kmenové buňky cytologie metabolismus MeSH
- neurální trubice cytologie embryologie metabolismus MeSH
- neurulace * MeSH
- pluripotentní kmenové buňky cytologie metabolismus MeSH
- transkripční faktor PAX6 genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Although histone acetylation is one of the most widely studied epigenetic modifications, there is still a lack of information regarding how the acetylome is regulated during brain development and pathophysiological processes. We demonstrate that the embryonic brain (E15) is characterized by an increase in H3K9 acetylation as well as decreases in the levels of HDAC1 and HDAC3. Moreover, experimental induction of H3K9 hyperacetylation led to the overexpression of NCAM in the embryonic cortex and depletion of Sox2 in the subventricular ependyma, which mimicked the differentiation processes. Inducing differentiation in HDAC1-deficient mouse ESCs resulted in early H3K9 deacetylation, Sox2 downregulation, and enhanced astrogliogenesis, whereas neuro-differentiation was almost suppressed. Neuro-differentiation of (wt) ESCs was characterized by H3K9 hyperacetylation that was associated with HDAC1 and HDAC3 depletion. Conversely, the hippocampi of schizophrenia-like animals showed H3K9 deacetylation that was regulated by an increase in both HDAC1 and HDAC3. The hippocampi of schizophrenia-like brains that were treated with the cannabinoid receptor-1 inverse antagonist AM251 expressed H3K9ac at the level observed in normal brains. Together, the results indicate that co-regulation of H3K9ac by HDAC1 and HDAC3 is important to both embryonic brain development and neuro-differentiation as well as the pathophysiology of a schizophrenia-like phenotype.
- MeSH
- acetylace MeSH
- antagonisté kanabinoidních receptorů farmakologie MeSH
- antipsychotika farmakologie MeSH
- časové faktory MeSH
- epigeneze genetická MeSH
- gestační stáří MeSH
- histondeacetylasa 1 antagonisté a inhibitory genetika metabolismus MeSH
- histondeacetylasy genetika metabolismus MeSH
- histony metabolismus MeSH
- inhibitory histondeacetylas farmakologie MeSH
- methylazoxymethanolacetát MeSH
- modely nemocí na zvířatech MeSH
- molekuly buněčné adheze nervové genetika metabolismus MeSH
- mozek účinky léků embryologie enzymologie patologie MeSH
- myši inbrední C57BL MeSH
- neurogeneze * účinky léků MeSH
- neurony účinky léků enzymologie patologie MeSH
- posttranslační úpravy proteinů MeSH
- potkani Sprague-Dawley MeSH
- receptor kanabinoidní CB1 antagonisté a inhibitory metabolismus MeSH
- schizofrenie chemicky indukované farmakoterapie enzymologie genetika MeSH
- signální transdukce MeSH
- transkripční faktory SOXB1 genetika metabolismus MeSH
- vývojová regulace genové exprese MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Extensive research in the field of stem cells and developmental biology has revealed evidence of the role of hypoxia as an important factor regulating self-renewal and differentiation. However, comprehensive information about the exact hypoxia-mediated regulatory mechanism of stem cell fate during early embryonic development is still missing. Using a model of embryoid bodies (EBs) derived from murine embryonic stem cells (ESC), we here tried to encrypt the role of hypoxia-inducible factor 1α(HIF1α) in neural fate during spontaneous differentiation. EBs derived from ESC with the ablated gene for HIF1αhad abnormally increased neuronal characteristics during differentiation. An increased neural phenotype inHif1α-/-EBs was accompanied by the disruption ofβ-catenin signaling together with the increased cytoplasmic degradation ofβ-catenin. The knock-in ofHif1α, as well asβ-catenin ectopic overexpression inHif1α-/-EBs, induced a reduction in neural markers to the levels observed in wild-type EBs. Interestingly, direct interaction between HIF1αandβ-catenin was demonstrated by immunoprecipitation analysis of the nuclear fraction of wild-type EBs. Together, these results emphasize the regulatory role of HIF1αinβ-catenin stabilization during spontaneous differentiation, which seems to be a crucial mechanism for the natural inhibition of premature neural differentiation.
- Publikační typ
- časopisecké články MeSH
Reactive oxygen species (ROS) are important regulators of cellular functions. In embryonic stem cells, ROS are suggested to influence differentiation status. Regulated ROS formation is catalyzed primarily by NADPH-dependent oxidases (NOXs). Apocynin and diphenyleneiodonium are frequently used inhibitors of NOXs; however, both exhibit uncharacterized effects not related to NOXs inhibition. Interestingly, in our model of mouse embryonic stem cells we demonstrate low expression of NOXs. Therefore we aimed to clarify potential side effects of these drugs. Both apocynin and diphenyleneiodonium impaired proliferation of cells. Surprisingly, we observed prooxidant activity of these drugs determined by hydroethidine. Further, we revealed that apocynin inhibits PI3K/Akt pathway with its downstream transcriptional factor Nanog. Opposite to this, apocynin augmented activity of canonical Wnt signaling. On the contrary, diphenyleneiodonium activated both PI3K/Akt and Erk signaling pathways without affecting Wnt. Our data indicates limits and possible unexpected interactions of NOXs inhibitors with intracellular signaling pathways.
- MeSH
- acetofenony farmakologie MeSH
- extracelulárním signálem regulované MAP kinasy metabolismus MeSH
- fosfatidylinositol-3-kinasy metabolismus MeSH
- fosforylace účinky léků MeSH
- myší embryonální kmenové buňky účinky léků metabolismus MeSH
- myši MeSH
- NADPH-oxidasy genetika metabolismus MeSH
- oniové sloučeniny farmakologie MeSH
- oxidační stres účinky léků MeSH
- proliferace buněk účinky léků MeSH
- proteiny Wnt metabolismus MeSH
- protoonkogenní proteiny c-akt metabolismus MeSH
- reaktivní formy kyslíku metabolismus MeSH
- synergismus léků MeSH
- transkripční faktor STAT3 metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Studies on fixed samples or genome-wide analyses of nuclear processes are useful for generating snapshots of a cell population at a particular time point. However, these experimental approaches do not provide information at the single-cell level. Genome-wide studies cannot assess variability between individual cells that are cultured in vitro or originate from different pathological stages. Immunohistochemistry and immunofluorescence are fundamental experimental approaches in clinical laboratories and are also widely used in basic research. However, the fixation procedure may generate artifacts and prevents monitoring of the dynamics of nuclear processes. Therefore, live-cell imaging is critical for studying the kinetics of basic nuclear events, such as DNA replication, transcription, splicing, and DNA repair. This review is focused on the advanced microscopy analyses of the cells, with a particular focus on live cells. We note some methodological innovations and new options for microscope systems that can also be used to study tissue sections. Cornerstone methods for the biophysical research of living cells, such as fluorescence recovery after photobleaching and fluorescence resonance energy transfer, are also discussed, as are studies on the effects of radiation at the individual cellular level.
We studied the histone signature of embryonic and adult brains to strengthen existing evidence of the importance of the histone code in mouse brain development. We analyzed the levels and distribution patterns of H3K9me1, H3K9me2, H3K9me3, and HP1β in both embryonic and adult brains. Western blotting showed that during mouse brain development, the levels of H3K9me1, H3K9me2, and HP1β exhibited almost identical trends, with the highest protein levels occurring at E15 stage. These trends differed from the relatively stable level of H3K9me3 at developmental stages E8, E13, E15, and E18. Compared with embryonic brains, adult brains were characterized by very low levels of H3K9me1/me2/me3 and HP1β. Manipulation of the embryonic epigenome through histone deacetylase inhibitor treatment did not affect the distribution patterns of the studied histone markers in embryonic ventricular ependyma. Similarly, Hdac3 depletion in adult animals had no effect on histone methylation in the adult hippocampus. Our results indicate that the distribution of HP1β in the embryonic mouse brain is related to that of H3K9me1/me2 but not to that of H3K9me3. The unique status of H3K9me3 in the brain was confirmed by its pronounced accumulation in the granular layer of the adult olfactory bulb. Moreover, among the studied proteins, H3K9me3 was the only posttranslational histone modification that was highly abundant at clusters of centromeric heterochromatin, called chromocenters. When we focused on the hippocampus, we found this region to be rich in H3K9me1 and H3K9me3, whereas H3K9me2 and HP1β were present at a very low level or even absent in the hippocampal blade. Taken together, these results revealed differences in the epigenome of the embryonic and adult mouse brain and showed that the adult hippocampus, the granular layer of the adult olfactory bulb, and the ventricular ependyma of the embryonic brain are colonized by specific epigenetic marks.
- MeSH
- chromozomální proteiny, nehistonové analýza metabolismus MeSH
- fluorescenční mikroskopie MeSH
- histonlysin-N-methyltransferasa metabolismus MeSH
- imunohistochemie MeSH
- mozek embryologie metabolismus MeSH
- myši inbrední C57BL MeSH
- myši knockoutované MeSH
- myši MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The antioxidative potential of the Manduca sexta adipokinetic hormone (Manse-AKH) in the last instar larvae of Spodoptera littoralis (Noctuidae, Lepidoptera) was demonstrated after exposure to oxidative stress (OS) elicited by feeding on artificial diet containing tannic acid (TA). Determination of protein carbonyls (PCs) and reduced glutathione (GSH) levels, monitoring of activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione-S-transferases (GSTs), as well as measuring of the mRNA expression of CAT and SOD were used as markers of the OS. Injection of the Manse-AKH (5 pmol per individual) reversed the OS status by mitigation of PCs formation and by stimulation of glutathione-S-transferases (GSTs) activity. The CAT and SOD mRNA expression was significantly suppressed after the Manse-AKH injection while activity of these enzymes was not affected. These results indicate that diminishing of OS after the AKH injection might be a result of activation of specific enzymatic pathway possibly at the post-translational level rather than a direct effect on regulation of antioxidant marker genes at the transcriptional level.
- MeSH
- antioxidancia metabolismus MeSH
- dieta MeSH
- glutathion metabolismus MeSH
- glutathiontransferasa metabolismus MeSH
- hmyzí hormony farmakologie MeSH
- hmyzí proteiny genetika metabolismus MeSH
- katalasa genetika metabolismus MeSH
- kyselina pyrrolidonkarboxylová analogy a deriváty farmakologie MeSH
- larva účinky léků genetika metabolismus MeSH
- Manduca chemie MeSH
- oligopeptidy farmakologie MeSH
- oxidační stres účinky léků MeSH
- polymerázová řetězová reakce s reverzní transkripcí MeSH
- regulace genové exprese enzymů účinky léků MeSH
- Spodoptera účinky léků genetika metabolismus MeSH
- superoxiddismutasa genetika metabolismus MeSH
- taniny aplikace a dávkování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
