Altering TET dioxygenase levels within physiological range affects DNA methylation dynamics of HEK293 cells
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE67351 | GEO | 2015/07/16
SECONDARY ACCESSION(S): PRJNA279558
REPOSITORIES: GEO
Similar Datasets
Project description:The TET family of dioxygenases (TET1/2/3) can convert 5-methylcytosine (5 mC) into 5-hydroxymethylcytosine (5 hmC) and has been shown to be involved in active and passive DNA demethylation. Here, we demonstrate that altering TET dioxygenase levels within physiological range can affect DNA methylation dynamics of HEK293 cells. Overexpression of TET1 increased global 5 hmC levels and was accompanied by mild DNA demethylation of promoters, gene bodies and CpG islands. Conversely, the simultaneous knockdown of TET1, TET2, and TET3 led to decreased global 5 hmC levels and mild DNA hypermethylation of above-mentioned regions. The methylation changes observed in the overexpression and knockdown studies were mostly non-reciprocal and occurred with different preference depending on endogenous methylation and gene expression levels. Single-nucleotide 5 hmC profiling performed on a genome-wide scale revealed that TET1 overexpression induced 5 mC oxidation without a distribution bias among genetic elements and structures. Detailed analysis showed that this oxidation was related to endogenous 5 hmC levels. In addition, our results support the notion that the effects of TET1 overexpression on gene expression are generally unrelated to its catalytic activity.
| S-EPMC4622922 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2015-07-16 | E-GEOD-67351 | biostudies-arrayexpress
Project description:To characterize target specificity of TETi76, we performed global gene expression analyses of K562TET2+/+ and TET2-/- control cells; TETi76 mimicked expression signatures generated by the loss of TET2 in K562. The addition of Ascorbic Acid (AA), known to enhance TET-dioxygenase activity, counteracted the changes induced by TETi76. In order to study the molecular pathway of synthetic lethality by TET-dioxygenase inhibition, natural TET2-/- mutant cell line SIGM5 was treated with TET inhibitor TETi76 and global gene expression analysis was performed by RNAseq. Result demostrate a significant upregulation of TNT-α signaling and the down regulation of Interferon-α signaling. Interestingly, we also observed significant up-modulation of oxidative stress response pathway genes consistent with the inhibition of dioxygenases. In particular, TETi76 treatment induces 8-fold increase of oxidative stress sensor NQO1 a NRF2 target gene that has been shown earlier to induce pro-apoptotic cell death in cancer cells.
2020-12-03 | GSE162487 | GEO
Project description:ObjectiveIn the context of an ongoing debate on the potential risks of hypoxemia and hyperoxemia, it seems prudent to maintain the partial arterial oxygen pressure (PaO2) in a physiological range during administration of supplemental oxygen. The PaO2 and peripheral oxygen saturation (SpO2) are closely related and both are used to monitor oxygenation status. However, SpO2 values cannot be used as an exact substitute for PaO2. The aim of this study in acutely ill and stable patients was to determine at which SpO2 level PaO2 is more or less certain to be in the physiological range.MethodsThis is an observational study prospectively collecting data pairs of PaO2 and SpO2 values in patients admitted to the emergency room or intensive care unit (Prospective Inpatient Acutely ill cohort; PIA cohort). A second cohort of retrospective data of patients who underwent pulmonary function testing was also included (Retrospective Outpatient Pulmonary cohort; ROP cohort). Arterial hypoxemia was defined as PaO2 < 60 mmHg and hyperoxemia as PaO2 > 125 mmHg. The SpO2 cut-off values with the lowest risk of hypoxemia and hyperoxemia were determined as the 95th percentile of the observed SpO2 values corresponding with the observed hypoxemic and hyperoxemic PaO2 values.Results220 data pairs were collected in the PIA cohort. 95% of hypoxemic PaO2 measurements occurred in patients with an SpO2 below 94%, and 95% of hyperoxemic PaO2 measurements occurred in patients with an SpO2 above 96%. Additionally in the 1379 data pairs of the ROP cohort, 95% of hypoxemic PaO2 measurements occurred in patients with an SpO2 below 93%.ConclusionThe SpO2 level marking an increased risk of arterial hypoxemia is not substantially different in acutely ill versus stable patients. In acutely ill patients receiving supplemental oxygen an SpO2 target of 95% maximizes the likelihood of maintaining PaO2 in the physiological range.
| S-EPMC8118260 | biostudies-literature
Project description:BACKGROUND:The distinct functional effects of the replication-dependent histone H2A isoforms have been demonstrated; however, the mechanistic basis of the non-redundancy remains unclear. Here, we have investigated the specific functional contribution of the histone H2A isoform H2A1H, which differs from another isoform H2A2A3 in the identity of only three amino acids. RESULTS:H2A1H exhibits varied expression levels in different normal tissues and human cancer cell lines (H2A1C in humans). It also promotes cell proliferation in a context-dependent manner when exogenously overexpressed. To uncover the molecular basis of the non-redundancy, equilibrium unfolding of recombinant H2A1H-H2B dimer was performed. We found that the M51L alteration at the H2A-H2B dimer interface decreases the temperature of melting of H2A1H-H2B by ~ 3 °C as compared to the H2A2A3-H2B dimer. This difference in the dimer stability is also reflected in the chromatin dynamics as H2A1H-containing nucleosomes are more stable owing to M51L and K99R substitutions. Molecular dynamic simulations suggest that these substitutions increase the number of hydrogen bonds and hydrophobic interactions of H2A1H, enabling it to form more stable nucleosomes. CONCLUSION:We show that the M51L and K99R substitutions, besides altering the stability of histone-histone and histone-DNA complexes, have the most prominent effect on cell proliferation, suggesting that the nucleosome stability is intimately linked with the physiological effects observed. Our work provides insights into the molecular basis of the non-redundancy of the histone H2A isoforms that are being increasingly reported to be functionally important in varied physiological contexts.
| S-EPMC5648446 | biostudies-literature
Project description:How an estuary responds to sea level rise (SLR) is complex and depends on energy drivers (e.g., tides and river inflows), estuarine geometry (e.g., length and depth), intrinsic fluid properties (e.g., density), and bed/bank roughness. While changes to the tidal range under SLR can impact estuarine sediment transport, water quality, and vegetation communities, studies on the altered tidal range under SLR are often based on case studies with outcomes applicable to a specific site. As such, this study produced a large ensemble of estuarine hydrodynamic models (>1800) to provide a systematic understanding of how tidal range dynamics within different estuary types may change under various SLR and river inflow scenarios. The results indicated that SLR often amplifies the tidal range of different estuary types, except for short estuaries with a low tidal range at the mouth where SLR attenuates the tides. SLR alters the location of the points with minimum tidal range and overall tidal range patterns in an estuary. Variations in tidal range were more evident in converging estuaries, shallower systems, or in estuaries with strong river inflows. These findings provide an indication of how different estuary types may respond to estuaries and may assist estuarine managers and decision makers.
| S-EPMC8452028 | biostudies-literature
Project description:Ten-eleven translocation (TET) proteins are dioxygenases that convert 5-methylcytosine (5mC) into 5-hydroxylmethylcytosine (5hmC) in DNA and RNA. However, their involvement in adult stem cell regulation remains unclear. Here, we identify a novel enzymatic activity-independent function of Tet in the Drosophila germline stem cell (GSC) niche. Tet activates the expression of Dpp, the fly homologue of BMP, in the ovary stem cell niche, thereby controlling GSC self-renewal. Depletion of Tet disrupts Dpp production, leading to premature GSC loss. Strikingly, both wild-type and enzyme-dead mutant Tet proteins rescue defective BMP signaling and GSC loss when expressed in the niche. Mechanistically, Tet interacts directly with Bap55 and Stat92E, facilitating recruitment of the Polybromo Brahma associated protein (PBAP) complex to the dpp enhancer and activating Dpp expression. Furthermore, human TET3 can effectively substitute for Drosophila Tet in the niche to support BMP signaling and GSC self-renewal. Our findings highlight a conserved novel catalytic activity-independent role of Tet as a scaffold protein in supporting niche signaling for adult stem cell self-renewal.
| S-SCDT-10_1038-S44318-024-00074-9 | biostudies-other
Project description:TET methylcytosine dioxygenases are essential for the stability and function of regulatory T cells (Treg cells), which maintain immune homeostasis and self-tolerance and express the lineage-determining transcription factor Foxp3. Here, we use whole-genome analyses to show that the transcriptional program and epigenetic features (DNA modification, chromatin accessibility) of Treg cells are attenuated in the absence of Tet2 and Tet3. Conversely, the addition of the TET activator vitamin C during TGFβ-induced iTreg cell differentiation in vitro potentiates the expression of Treg signature genes and alters the epigenetic landscape to better resemble that of Treg cells generated in vivo. Vitamin C enhances IL-2 responsiveness in iTreg cells by increasing IL2Rα expression, STAT5 phosphorylation, and STAT5 binding, mimicking the IL-2/STAT5 dependence of Treg cells generated in vivo. In summary, TET proteins play essential roles in maintaining Treg molecular features and promoting their dependence on IL-2. TET activity during endogenous Treg development and potentiation of TET activity by vitamin C during iTreg differentiation are necessary to maintain the transcriptional and epigenetic features of Treg cells.
| S-EPMC8339674 | biostudies-literature
Project description:More than just a container for DNA, the nuclear envelope carries out a wide variety of critical and highly regulated cellular functions. One of these functions is nuclear import, and in this study we investigate how altering the levels of nuclear transport factors impacts developmental progression and organismal size. During early Xenopus laevis embryogenesis, the timing of a key developmental event, the midblastula transition (MBT), is sensitive to nuclear import factor levels. How might altering nuclear import factors and MBT timing in the early embryo affect downstream development of the organism? We microinjected X. laevis two-cell embryos with mRNA to increase levels of importin α or NTF2, resulting in differential amounts of nuclear import factors in the two halves of the embryo. Compared to controls, these embryos exhibited delayed gastrulation, curved neural plates, and bent tadpoles with different sized eyes. Furthermore, embryos microinjected with NTF2 developed into smaller froglets compared to control microinjected embryos. We propose that altering nuclear import factors and nuclear size affects MBT timing, cell size, and cell number, subsequently disrupting later development. Thus, altering nuclear import factors early in development can affect function and size at the organismal level.
| S-EPMC6476522 | biostudies-literature
Project description:TET2 is one of the most frequently mutated genes in myeloid neoplasms. TET2 loss-of-function perturbs myeloid differentiation and causes clonal expansion. Despite extensive knowledge regarding biochemical mechanisms underlying distorted myeloid differentiation, targeted therapies are lagging. Here we review known biochemical mechanisms and candidate therapies that emerge from this. Specifically, we discuss the potential utility of vitamin C to compensate for TET-dioxygenase deficiency, to thereby restore the biochemical function. An alternative approach exploits the TET-deficient state for synthetic lethality, exploiting the fact that a minimum level of TET-dioxygenase activity is required for cell survival, rendering TET2-mutant malignant cells selectively vulnerable to inhibitors of TET-function.
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