Dynamic changes of global DNA methylation and hypermethylation of cell adhesion-related genes in rat kidneys in response to ochratoxin A

2015 ◽  
Vol 8 (4) ◽  
pp. 465-476 ◽  
Author(s):  
X. Li ◽  
J. Gao ◽  
K. Huang ◽  
X. Qi ◽  
Q. Dai ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Cell Adhesion ◽  
Ochratoxin A ◽  
Transcriptional Activation ◽  
Dna Methyltransferase ◽  
Dna Methyltransferases ◽  
Global Dna Methylation ◽  
Specific Cell

Ochratoxin A (OTA), which is found in a variety of food products, is associated with the development of nephrotoxicity and carcinogenicity in rats and has raised public health concerns. A previous study in our laboratory indicated that OTA exposure induced cytotoxicity by decreasing global DNA methylation in vitro. However, the relationship between OTA-induced nephrotoxicity and DNA methylation changes in vivo remains unclear. The object of this study was to investigate whether OTA can change global DNA methylation or alter the expression of several critical tumour-related genes by inducing methylation modifications before carcinogenesis. We focused on the mechanism of action of OTA in regard to DNA methylation, including the expression of DNA methyltransferases and the regulation of specific cell signalling pathways. Dynamic and dose-dependent changes of global DNA methylation were observed during OTA-induced nephrotoxicity and probably associated with the expression of DNA methyltransferase 1. 13-week exposure of OTA caused hypermethylation in the promoters of critical cell adhesion-related genes, E-cadherin and N-cadherin, leading to reduction of the corresponding mRNA expression, accompanied by transcriptional activation of the Wnt and PI3K/AKT pathways. These findings suggested that long-term OTA exposure could disrupt DNA methylation profile, which might be one of the possible mechanisms of OTA-induced nephrotoxicity.

scholarly journals Continuous Zebularine Treatment Effectively Sustains Demethylation in Human Bladder Cancer Cells

2004 ◽  
Vol 24 (3) ◽  
pp. 1270-1278 ◽  
Author(s):  
Jonathan C. Cheng ◽  
Daniel J. Weisenberger ◽  
Felicidad A. Gonzales ◽  
Gangning Liang ◽  
Guo-Liang Xu ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dna Methyltransferase ◽  
Promoter Regions ◽  
Bladder Cancer Cells ◽  
Continuous Application ◽  
Aberrant Dna Methylation ◽  
Human Bladder Cancer Cells ◽  
Partial Depletion

ABSTRACT During tumorigenesis, tumor suppressor and cancer-related genes are commonly silenced by aberrant DNA methylation in their promoter regions. Recently, we reported that zebularine [1-(β-d-ribofuranosyl)-1,2-dihydropyrimidin-2-one] acts as an inhibitor of DNA methylation and exhibits chemical stability and minimal cytotoxicity both in vitro and in vivo. Here we show that continuous application of zebularine to T24 cells induces and maintains p16 gene expression and sustains demethylation of the 5′ region for over 40 days, preventing remethylation. In addition, continuous zebularine treatment effectively and globally demethylated various hypermethylated regions, especially CpG-poor regions. The drug caused a complete depletion of extractable DNA methyltransferase 1 (DNMT1) and partial depletion of DNMT3a and DNMT3b3. Last, sequential treatment with 5-aza-2′-deoxycytidine followed by zebularine hindered the remethylation of the p16 5′ region and gene resilencing, suggesting the possible combination use of both drugs as a potential anticancer regimen.

scholarly journals SIRT6 Promotes Osteogenic Differentiation of Adipose-Derived Mesenchymal Stem Cells Through Antagonizing DNMT1

2021 ◽  
Vol 9 ◽  
Author(s):  
Bo Jia ◽  
Jun Chen ◽  
Qin Wang ◽  
Xiang Sun ◽  
Jiusong Han ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Stem Cells ◽  
Notch Signaling ◽  
Osteogenic Differentiation ◽  
Dna Methyltransferases ◽  
Luciferase Reporter ◽  
Calcium Deposition ◽  
Alizarin Red

BackgroundAdipose-derived stem cells (ADSCs) are increasingly used in regenerative medicine because of their potential to differentiate into multiple cell types, including osteogenic lineages. Sirtuin protein 6 (SIRT6) is a nicotinamide adenine dinucleotide (NAD)-dependent deacetylase that plays important roles in cell differentiation. NOTCH signaling has also been reported to involve in osteogenic differentiation. However, the function of SIRT6 in osteogenic differentiation of ADSCs and its relation to the NOTCH signaling pathways are yet to be explored.MethodsThe in vitro study with human ADSCs (hADSCs) and in vivo experiments with nude mice have been performed. Alkaline phosphatase (ALP) assays and ALP staining were used to detect osteogenic activity. Alizarin Red staining was performed to detect calcium deposition induced by osteogenic differentiation of ADSCs. Western blot, RT-qPCR, luciferase reporter assay, and co-immunoprecipitation assay were applied to explore the relationship between of SIRT6, DNA methyltransferases (DNMTs) and NOTCHs.ResultsSIRT6 promoted ALP activity, enhanced mineralization and upregulated expression of osteogenic-related genes of hADSCs in vitro and in vivo. Further mechanistic studies showed that SIRT6 deacetylated DNMT1, leading to its unstability at protein level. The decreased expression of DNMT1 prevented the abnormal DNA methylation of NOTCH1 and NOTCH2, resulting in the upregulation of their transcription. SIRT6 overexpression partially suppressed the abnormal DNA methylation of NOTCH1 and NOTCH2 by antagonizing DNMT1, leading to an increased capacity of ADSCs for their osteogenic differentiation.ConclusionThis study demonstrates that SIRT6 physical interacts with the DNMT1 protein, deacetylating and destabilizing DNMT1 protein, leading to the activation of NOTCH1 and NOTCH2, Which in turn promotes the osteogenic differentiation of ADSCs.

scholarly journals Targeting the Tumour-Specific Spliceosome Through In Silico Virtual Screening for Discovery of New SF3B1 Small Molecule Inhibitors

2018 ◽  
Vol 4 (Supplement 2) ◽  
pp. 201s-201s
Author(s):  
L.Z. Wong
Keyword(s):  
Virtual Screening ◽  
Vitamin D3 ◽  
Transcriptional Activation ◽  
Messenger Rna ◽  
Binding Free Energy ◽  
Specific Cell ◽  
Breast Cancers ◽  
Eukaryotic Genes

Background: The coding (exon) and noncoding (intron) eukaryotic genes are expressed as precursor messenger RNA (premRNA). mRNA splicing defines the process by which introns are excised from premRNA and flanking exons are ligated together. This process is catalyzed by the spliceosome in which combination of small nuclear ribonucleoproteins (U1, U2, U4, U5, U6) forms a spliceosome. The SF3B1 protein is a core component of the U2 snRNP that binds to the branch site and facilitate RNA splicing. Recent studies have identified mutations and dysregulation of in SF3B1 activities in subsets of human cancers including chronic lymphocytic leukemias (CLLs), uveal melanomas, pancreatic cancers and breast cancers. Despite promising in vivo results indicating the potential of spliceosome modulators in targeting the refractory breast cancers, the preclinical and clinical development of such modulators will take several years to complete. Aim: In the current study, we sought to identify new SF3B1 modulators using massive virtual screening of FDA-approved drugs or novel agents for drug repurposing. Methods: A total of 3000 compounds were screened and the hits were identified based on the binding free energy (kcal/mol) of the molecules to the predicted binding sites. Of the 90 hits, vitamin D3 and its analogs (calcipotriol and calcitriol) were identified as a putative SF3B1 modulators. Results: Further in vitro testing revealed that vitamin D3 and its analogs induced significant mRNA misplicing and tumor-specific cell death in MCF7 and MDA-MB-468. Further analyses revealed that vitamin D3 and its analogs significantly reduce SF3B1 protein expression with no changes in its mRNA expression. Conclusion: These results suggest that vitamin D3 and its analogs might interact with SF3B1 to induce protein degradation rather than transcriptional activation.

scholarly journals Global DNA methylation: role, status and genome-wide approaches to study epigenetic mark in cloned embryos

2020 ◽  
pp. 41-59
Author(s):  
Shivani Malpotra ◽  
Ahmad Hussain
Keyword(s):  
Dna Methylation ◽  
Developmental Stages ◽  
Gene Expression Pattern ◽  
Methylation Profile ◽  
Global Dna Methylation ◽  
Epigenetic Mark ◽  
Dna Methylation Profile ◽  
Low Efficiency

Somatic cell nuclear transfer (SCNT) technique has been proving its worth for more than two decades now as over 20 different species have been successfully cloned. SCNT protocol for cloning is well established but efficiency in terms of live birth rate is still low. Epigenetic abnormality following nuclear reprogramming is considered as the main culprit behind its low efficiency. DNA methylation is one of the most important epigenetic modifications that directly or indirectly regulate gene expression pattern, development and genome stability. Embryos produced through SCNT are found to express abnormal DNA methylation profile in comparison with in vivo or in vitro produced embryos. In order to improve DNA methylation profile in cloned embryos, a complete database of whole genome is required to find out specific faulty targets. Many techniques including low throughput and high throughput approach has been used to profile DNA methylation pattern in bovine embryos throughout the developmental stages. In the present review, we have compiled the overall status of global DNA methylation, the effect of aberrant DNA methylation on development and evolution in methodologies used for profiling global DNA methylome in cloned embryos.

scholarly journals O6D.2 Evidence of dna methylation changes by carbon nanotubes in a translational study design

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A57.2-A57
Author(s):  
Manosij Ghosh ◽  
Deniz Öner ◽  
Lode Godderis ◽  
Peter Hoet
Keyword(s):  
Dna Methylation ◽  
Cross Sectional Study ◽  
Methylation Pattern ◽  
Global Dna Methylation ◽  
Limited Information ◽  
Cross Sectional ◽  
Translational Study ◽  
Exposed Workers

IntroductionWhile studies have addressed genotoxic effects of CNT, only limited information are available on epigenetic effects. We designed a study to investigate DNA methylation alterations in vitro, in vivo and in occupationally exposed workers.Material and methodsIn vitro studies were performed in 16-HBE and THP-1 cells. For the in vivo study, BALB/c mice were administered intratracheally with single-wall CNT (SWCNTs) and multi-wall (MWCNTs) at high (2.5 mg/kg) and low (0.25 mg/kg) doses. For the cross sectional study, 24 workers exposed to aggregates of MWCNT of 500 nm–100 µm with concentrations of 4.6–42.6 µg/m3 and 43 unexposed referents were recruited. Global DNA methylation and demethylation patterns were analysed by LC-MS/MS. Methylation of specific genes was measured by Pyromark 24® (Qiagen). Genome-wide assessment of DNA methylation was performed with Infinium HumanMethylation450 BeadChip Array.ResultsIn general, we did not find global DNA methylation alteration for both CNTs. In 16-HBE cells, differentially methylated and expressed genes (MWCNTs>SWCNTs) from p53 signalling, DNA damage repair and cell cycle pathways were observed. In THP-1 cells, CNTs induced promoter-specific methylation of genes involved in several signaling cascade, vascular endothelial growth factor and platelet activation pathways. In lungs of BALB/c mice CNTs affected methylation of ATM gene. Finally, analysis of gene-specific DNA methylation in exposed workers revealed significant changes for DNMT1, ATM, SKI, and HDAC4 promoter CpGs.ConclusionsEpigenetic changes seem to occur at sub cyto-genotoxic concentrations in vitro. Alteration in DNA methylation pattern could be a natural reaction of cells but could also silence critical genes and reprogram cellular functions.

scholarly journals A new member of the I kappaB protein family, I kappaB epsilon, inhibits RelA (p65)-mediated NF-kappaB transcription.

1997 ◽  
Vol 17 (10) ◽  
pp. 6184-6190 ◽  
Author(s):  
Z Li ◽  
G J Nabel
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Transcriptional Activation ◽  
Interleukin 1 ◽  
Specific Cell ◽  
Alternative Mechanism ◽  
Necrosis Factor Alpha ◽  
Nf Kappab

A novel member of the I kappaB family has been identified as a protein that associated with the p50 subunit of NF-kappaB in a yeast two-hybrid screen. Similar to previously known I kappaB proteins, this member, I kappaB epsilon, has six consecutive ankyrin repeats. I kappaB epsilon mRNA is widely expressed in different human tissues, with highest levels in spleen, testis, and lung. I kappaB epsilon interacts with different NF-kappaB proteins, including p65 (RelA), c-Rel, p50, and p52, in vitro and in vivo and inhibits the DNA-binding activity of both p50-p65 and p50-c-Rel complexes effectively. Endogenous and transfected NF-kappaB (RelA-dependent) transcriptional activation is inhibited by I kappaB epsilon. I kappaB epsilon mRNA is expressed at different levels in specific cell types and is synthesized constitutively in transformed B-cell lines. It also displays differential induction in response to tumor necrosis factor alpha, interleukin-1, or phorbol ester stimulation compared to I kappaB alpha in non-B-cell lines. Therefore, I kappaB epsilon represents a novel I kappaB family member which provides an alternative mechanism for regulation of NF-kappaB-dependent transcription.

scholarly journals Differential regulation of DNA methylation versus histone acetylation in cardiomyocytes during HHcy in vitro and in vivo: an epigenetic mechanism

2014 ◽  
Vol 46 (7) ◽  
pp. 245-255 ◽  
Author(s):  
Pankaj Chaturvedi ◽  
Anuradha Kalani ◽  
Srikanth Givvimani ◽  
Pradip Kumar Kamat ◽  
Anastasia Familtseva ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Histone Acetylation ◽  
Dna Methyltransferase ◽  
Epigenetic Mechanism ◽  
Dependent Manner ◽  
Histone Deacetylase 1 ◽  
H3k9 Acetylation ◽  
Dose Dependent

The mechanisms of homocysteine-mediated cardiac threats are poorly understood. Homocysteine, being the precursor to S-adenosyl methionine (a methyl donor) through methionine, is indirectly involved in methylation phenomena for DNA, RNA, and protein. We reported previously that cardiac-specific deletion of N-methyl-d-aspartate receptor-1 (NMDAR1) ameliorates homocysteine-posed cardiac threats, and in this study, we aim to explore the role of NMDAR1 in epigenetic mechanisms of heart failure, using cardiomyocytes during hyperhomocysteinemia (HHcy). High homocysteine levels activate NMDAR1, which consequently leads to abnormal DNA methylation vs. histone acetylation through modulation of DNA methyltransferase 1 (DNMT1), HDAC1, miRNAs, and MMP9 in cardiomyocytes. HL-1 cardiomyocytes cultured in Claycomb media were treated with 100 μM homocysteine in a dose-dependent manner. NMDAR1 antagonist (MK801) was added in the absence and presence of homocysteine at 10 μM in a dose-dependent manner. The expression of DNMT1, histone deacetylase 1 (HDAC1), NMDAR1, microRNA (miR)-133a, and miR-499 was assessed by real-time PCR as well as Western blotting. Methylation and acetylation levels were determined by checking 5′-methylcytosine DNA methylation and chromatin immunoprecipitation. Hyperhomocysteinemic mouse models (CBS+/−) were used to confirm the results in vivo. In HHcy, the expression of NMDAR1, DNMT1, and matrix metalloproteinase 9 increased with increase in H3K9 acetylation, while HDAC1, miR-133a, and miR-499 decreased in cardiomyocytes. Similar results were obtained in heart tissue of CBS+/− mouse. High homocysteine levels instigate cardiovascular remodeling through NMDAR1, miR-133a, miR-499, and DNMT1. A decrease in HDAC1 and an increase in H3K9 acetylation and DNA methylation are suggestive of chromatin remodeling in HHcy.

scholarly journals Modulation of DNA Methylation Influences Cartilage Formation in Murine Chondrogenic Models

2021 ◽  
Author(s):  
Judit Vágó ◽  
Katalin Kiss ◽  
Edina Karanyicz ◽  
Roland Takács ◽  
Csaba Matta ◽  
...  
Keyword(s):  
Dna Methylation ◽  
In Situ Hybridization ◽  
Dna Methyltransferase ◽  
Mouse Cell ◽  
Dna Demethylation ◽  
Specific Gene ◽  
Cartilage Formation

The aim of this study was to investigate the role of DNA methylation in the regulation of in vitro and in vivo cartilage formation. Based on the data of an RNA chip-assay performed on chondrifying BMP2-overexpressing C3H10T1/2 cells, the relative expression of Tet1 (tet methylcytosine dioxygenase 1), Dnmt3a (DNA methyltransferase 3) and Ogt (O-linked N-acetylglucosamine transferase) genes was examined with RT-qPCR in mouse cell-line based and primary micromass cultures. RNA probes for in situ hybridization were used on frozen sections of 15-day-old mouse embryos. DNA methylation was inhibited with 5-azacytidine during culturing. We found very strong but gradually decreasing expression of Tet1 throughout the entire course of in vitro cartilage differentiation along with strong signals in the cartilaginous embryonic skeleton. Dnmt3a and Ogt expressions did not show significant changes with RT-qPCR and gave weak in situ hybridization signals. Inhibition of DNA methylation applied during early stages of differentiation reduced cartilage-specific gene expression and cartilage formation. In contrast, it had stimulatory effect when added to differentiated chondrocytes. Our results indicate that the DNA demethylation-inducing Tet1 is a significant epigenetic factor of chondrogenesis, and inhibition of DNA methylation exerts distinct effects in different phases of in vitro cartilage formation.

69 BLASTOCYSTS DEVELOPED FROM EMBRYOS THAT SPENT UP TO 2-CELL STAGE IN VIVO EXHIBITED MASSIVE DNA METHYLATION DYSREGULATION INCLUDING IMPRINTED GENES AND DNA METHYLTRANSFERASES

2017 ◽  
Vol 29 (1) ◽  
pp. 142 ◽  
Author(s):  
D. Salilew-Wondim ◽  
M. Hoelker ◽  
U. Besenfelder ◽  
V. Havlicek ◽  
E. Held ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Culture Condition ◽  
Dna Methyltransferases ◽  
Cell Stage ◽  
Embryonic Genome ◽  
Genomic Regions ◽  
Methylation Patterns ◽  
Genome Activation

Suboptimal culture condition before minor or major genome activation is believed to affect the quality and the transcriptome landscape of the resulting blastocysts. Thus, we hypothesised that exposure of bovine embryos to suboptimal culture condition before minor embryonic genome activation could affect the genome methylation patterns of the resulting blastocysts. Therefore, here we aimed to investigate the genome wide DNA methylation patterns of blastocysts derived from embryos developed up to 2-cell stages in vivo followed by in vitro culture. For this, Simmental heifers were superovulated and artificially inseminated. The 2-cell stage embryos were then flushed using a state-of-the-art nonsurgical endoscopic early-stage embryo flushing technique and in vitro cultured until the blastocyst stage. The DNA methylation patterns of these blastocysts were then determined with reference to blastocysts derived from embryos developed completely under in vivo condition. For this, the genomic DNA isolated from each blastocyst group were fragmented, and unmethylated genomic regions were cleaved using methylation sensitive restriction enzymes. The samples were then amplified using ligation mediated PCR and labelled either with Cy-3 or Cy-5 dyes in a dye-swap design using the ULS Fluorescent genomic DNA labelling kit (Kreatech Biotechnology) and hybridized on an EmbryoGENE DNA Methylation Array as described previously (Saadi 2014 BMC Genomics 15, 451; Salilew-Wondim 2015 PLoS ONE 10, e0140467). Array hybridization was performed for 40 h at 65°C, and 4 hybridizations were preformed to represent 4 biological replicates. The slides were scanned using Agilent’s High-Resolution C Scanner (Agilent Technologies, Santa Clara, CA, USA), and Agilent’s Feature Extraction software (Agilent Technologies) was used to extract data features. Differentially methylated regions with fold change ≥1.5 and P-value < 0.05 were identified using linear modelling for microarray and R software. The results have shown that including imprinted genes (PEG3, IGF1, RASGRF1, IGF2R, GRB10, SNRPN, and PLAGL1) and DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B), a total of 10,388 genomic regions were differentially methylated, of which 6393 genomic regions were hypermethylated in blastocysts derived from 2-cell flush compared with the complete vivo group. In addition, comparative analysis of the current DNA methylation data with our previous transcriptome profile data have shown that including DNMT3A, CTSZ, ElF3E, and PPP2R2B, the expression patterns of 603 genes was inversely correlated with the methylation patterns. Moreover, canonical pathways including gap junction, adherens junction, axon guidance, focal adhesion, and calcium signalling were affected by differentially methylated regions. Therefore, this study indicated that exposure of embryos to suboptimal culture condition before embryonic genome activation would lead to a massive dysregulation of methylation pattern of genes involved in developmentally relevant pathways in the resulting blastocysts.

scholarly journals Direct Physical and Functional Interaction of the NuA4 Complex Components Yaf9p and Swc4p

2004 ◽  
Vol 3 (4) ◽  
pp. 976-983 ◽  
Author(s):  
Claudia B. Bittner ◽  
Deniz T. Zeisig ◽  
Bernd B. Zeisig ◽  
Robert K. Slany
Keyword(s):  
Transcriptional Activation ◽  
Dna Methyltransferase ◽  
Chromatin Modification ◽  
Gel Filtration ◽  
Dominant Negative ◽  
Yeast Homolog ◽  
High Degree ◽  
Degree Of Similarity

ABSTRACT Saccharomyces cerevisiae Yaf9p and the mammalian leukemia-associated protein ENL share a high degree of similarity. To investigate the biological function of Yaf9p, this protein was used to search for interacting proteins in a two-hybrid system. Here, we demonstrate that Yaf9p binds directly to Swc4p, the yeast homolog of the mammalian DNA-methyltransferase-associated protein 1. Yaf9p and Swc4p associate through C-terminal domains, and both proteins coprecipitate in vitro in pull-down experiments and in vivo by immunoprecipitation. In living cells, Swc4p is present in a megadalton protein complex that shows a fractionation behavior in gel filtration similar to that of Esa1p, the histone acetyltransferase of the NuA4 complex. Recruitment of Yaf9p to DNA leads to promoter-specific transcriptional activation that can be inhibited by dominant negative Swc4p lacking the Yaf9p binding domain. Interference with Swc4p function also increases sensitivity to the microtubule toxin benomyl, a trait that corresponds to the known phenotype of a yaf9 − knockout strain. In summary, the results suggest that Yaf9p and Swc4p form a protein pair that has a role in chromatin modification with possible implications also for the function of their mammalian counterparts.

Sign in / Sign up

Export Citation Format

Share Document