scholarly journals HMGB1 Recruits TET2/AID/TDG to Induce DNA Demethylation in STAT3 Promoter in CD4+ T Cells from aGVHD Patients

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xuejun Xu ◽  
Yan Chen ◽  
Enyi Liu ◽  
Bin Fu ◽  
Juan Hua ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Immune Response ◽  
T Cells ◽  
Promoter Region ◽  
Critical Role ◽  
Underlying Mechanism ◽  
Dna Demethylation ◽  
Dna Hypomethylation ◽  
Promoter Dna Methylation ◽  
Promoter Dna

STAT3 is highly expressed in aGVHD CD4+ T cells and plays a critical role in inducing or worsening aGVHD. In our preceding studies, DNA hypomethylation in STAT3 promoter was shown to cause high expression of STAT3 in aGVHD CD4+ T cells, and the process could be modulated by HMGB1, but the underlying mechanism remains unclear. TET2, AID, and TDG are indispensable in DNA demethylation; meanwhile, TET2 and AID also serve extremely important roles in immune response. So, we speculated these enzymes involved in the STAT3 promoter hypomethylation induced by HMGB1 in aGVHD CD4+ T cells. In this study, we found that the binding levels of TET2/AID/TDG to STAT3 promoter were remarkably increased in CD4+T cells from aGVHD patients and were significantly negatively correlated with the STAT3 promoter methylation level. Simultaneously, we revealed that HMGB1 could recruit TET2, AID, and TDG to form a complex in the STAT3 promoter region. Interference with the expression of TET2/AID/TDG inhibited the overexpression of STAT3 caused by HMGB1 downregulation of the STAT3 promoter DNA methylation. These data demonstrated a new molecular mechanism of how HMGB1 promoted the expression of STAT3 in CD4+ T cells from aGVHD patients.

scholarly journals Paradoxical association of TET loss of function with genome-wide DNA hypomethylation

2019 ◽  
Vol 116 (34) ◽  
pp. 16933-16942 ◽  
Author(s):  
Isaac F. López-Moyado ◽  
Ageliki Tsagaratou ◽  
Hiroshi Yuita ◽  
Hyungseok Seo ◽  
Benjamin Delatte ◽  
...  
Keyword(s):  
Dna Methylation ◽  
T Cells ◽  
Genomic Analysis ◽  
Dna Demethylation ◽  
Potential Contribution ◽  
Loss Of Function ◽  
Dna Hypomethylation ◽  
Dna Hypermethylation ◽  
Hematopoietic Stem ◽  
Cancer Genomes

Cancer genomes are characterized by focal increases in DNA methylation, co-occurring with widespread hypomethylation. Here, we show that TET loss of function results in a similar genomic footprint. Both 5hmC in wild-type (WT) genomes and DNA hypermethylation in TET-deficient genomes are largely confined to the active euchromatic compartment, consistent with the known functions of TET proteins in DNA demethylation and the known distribution of 5hmC at transcribed genes and active enhancers. In contrast, an unexpected DNA hypomethylation noted in multiple TET-deficient genomes is primarily observed in the heterochromatin compartment. In a mouse model of T cell lymphoma driven by TET deficiency (Tet2/3 DKO T cells), genomic analysis of malignant T cells revealed DNA hypomethylation in the heterochromatic genomic compartment, as well as reactivation of repeat elements and enrichment for single-nucleotide alterations, primarily in heterochromatic regions of the genome. Moreover, hematopoietic stem/precursor cells (HSPCs) doubly deficient for Tet2 and Dnmt3a displayed greater losses of DNA methylation than HSPCs singly deficient for Tet2 or Dnmt3a alone, potentially explaining the unexpected synergy between DNMT3A and TET2 mutations in myeloid and lymphoid malignancies. Tet1-deficient cells showed decreased localization of DNMT3A in the heterochromatin compartment compared with WT cells, pointing to a functional interaction between TET and DNMT proteins and providing a potential explanation for the hypomethylation observed in TET-deficient genomes. Our data suggest that TET loss of function may at least partially underlie the characteristic pattern of global hypomethylation coupled to regional hypermethylation observed in diverse cancer genomes, and highlight the potential contribution of heterochromatin hypomethylation to oncogenesis.

scholarly journals DNA methylation markers in lung cancer

2020 ◽  
Vol 21 ◽  
Author(s):  
Yoonki Hong ◽  
Woo Jin Kim
Keyword(s):  
Lung Cancer ◽  
Dna Methylation ◽  
Early Stage ◽  
Lung Cancer Screening ◽  
Dna Demethylation ◽  
Diagnostic Methods ◽  
Common Cancer ◽  
Promoter Dna Methylation ◽  
Potential Alternative ◽  
Promoter Dna

: Lung cancer is the most common cancer and the leading cause of cancer-related morbidity and mortality worldwide. As early symptoms of lung cancer are minimal and non-specific, many patients are diagnosed at an advanced stage. Despite a concerted effort to diagnose lung cancer early, no biomarkers that can be used for lung cancer screening and prognosis prediction have been established so far. As global DNA demethylation and gene-specific promoter DNA methylation are present in lung cancer, DNA methylation biomarkers have become a major area of research as potential alternative diagnostic methods to detect lung cancer at an early stage. This review summarizes the emerging DNA methylation changes in lung cancer tumorigenesis, focusing on biomarkers for early detection and their potential clinical applications in lung cancer.

scholarly journals Critical Role of Histone Methylation in Tumor Suppressor Gene Silencing in Colorectal Cancer

2003 ◽  
Vol 23 (1) ◽  
pp. 206-215 ◽  
Author(s):  
Yutaka Kondo ◽  
LanLan Shen ◽  
Jean-Pierre J. Issa
Keyword(s):  
Gene Expression ◽  
Colorectal Cancer ◽  
Dna Methylation ◽  
Gene Silencing ◽  
Dna Methyltransferase ◽  
Critical Role ◽  
Histone H3 ◽  
Suppressor Gene ◽  
Promoter Dna Methylation ◽  
Promoter Dna

ABSTRACT The mechanism of DNA hypermethylation-associated tumor suppressor gene silencing in cancer remains incompletely understood. Here, we show by chromatin immunoprecipitation that for three genes (P16, MLH1, and the O 6-methylguanine-DNA methyltransferase gene, MGMT), histone H3 Lys-9 methylation directly correlates and histone H3 Lys-9 acetylation inversely correlates with DNA methylation in three neoplastic cell lines. Treatment with the histone deacetylase inhibitor trichostatin A (TSA) resulted in moderately increased Lys-9 acetylation at silenced loci with no effect on Lys-9 methylation and minimal effects on gene expression. By contrast, treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5Aza-dC) rapidly reduced Lys-9 methylation at silenced loci and resulted in reactivation for all three genes. Combined treatment with 5Aza-dC and TSA was synergistic in reactivating gene expression through simultaneous effects on Lys-9 methylation and acetylation, which resulted in a robust increase in the ratio of Lys-9 acetylated and methylated histones at loci showing dense DNA methylation. By contrast to Lys-9, histone H3 Lys-4 methylation inversely correlated with promoter DNA methylation, was not affected by TSA, and was increased moderately at silenced loci by 5Aza-dC. Our results suggest that reduced H3 Lys-4 methylation and increased H3 Lys-9 methylation play a critical role in the maintenance of promoter DNA methylation-associated gene silencing in colorectal cancer.

SMAD3 Is Upregulated in Human Osteoarthritic Cartilage Independent of the Promoter DNA Methylation

2015 ◽  
Vol 43 (2) ◽  
pp. 388-394 ◽  
Author(s):  
Erfan Aref-Eshghi ◽  
Ming Liu ◽  
Seyd Babak Razavi-Lopez ◽  
Kensuke Hirasawa ◽  
Patricia E. Harper ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Promoter Region ◽  
Transforming Growth Factor ◽  
Rank Correlation ◽  
Osteoarthritic Cartilage ◽  
Human Cartilage ◽  
Joint Replacement Surgery ◽  
Promoter Dna Methylation ◽  
Promoter Dna

Objective.To compare SMAD3 gene expression between human osteoarthritic and healthy cartilage and to examine whether expression is regulated by the promoter DNA methylation of the gene.Methods.Human cartilage samples were collected from patients undergoing total hip/knee joint replacement surgery due to primary osteoarthritis (OA), and from patients with hip fractures as controls. DNA/RNA was extracted from the cartilage tissues. Real-time quantitative PCR was performed to measure gene expression, and Sequenom EpiTyper was used to assay DNA methylation. Mann-Whitney test was used to compare the methylation and expression levels between OA cases and controls. Spearman rank correlation coefficient was calculated to examine the association between the methylation and gene expression.Results.A total of 58 patients with OA (36 women, 22 men; mean age 64 ± 9 yrs) and 55 controls (43 women, 12 men; mean age 79 ± 10 yrs) were studied. SMAD3 expression was on average 83% higher in OA cartilage than in controls (p = 0.0005). No difference was observed for DNA methylation levels in the SMAD3 promoter region between OA cases and controls. No correlation was found between SMAD3 expression and promoter DNA methylation.Conclusion.Our study demonstrates that SMAD3 is significantly overexpressed in OA. This overexpression cannot be explained by DNA methylation in the promoter region. The results suggest that the transforming growth factor-β/SMAD3 pathway may be overactivated in OA cartilage and has potential in developing targeted therapies for OA.

Genome-wide investigation of DNA methylation dynamics reveals a critical role of DNA demethylation during the early somatic embryogenesis of Dimocarpus longan Lour

2020 ◽  
Vol 40 (12) ◽  
pp. 1807-1826
Author(s):  
Xiaohui Chen ◽  
Xiaoping Xu ◽  
Xu Shen ◽  
Hansheng Li ◽  
Chen Zhu ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Somatic Embryogenesis ◽  
Dna Methyltransferase ◽  
Expression Patterns ◽  
Critical Role ◽  
Dna Demethylation ◽  
Structure Stability ◽  
Dna Hypomethylation ◽  
Dimocarpus Longan

Abstract DNA methylation plays essential roles in gene regulation, chromatin structure stability, gene imprinting, X chromosome inactivation and embryonic development. However, the dynamics and functions of DNA methylation during the early stage of longan (Dimocarpus longan) somatic embryogenesis (SE) are still unclear. In this study, we carried out whole genome bisulphite sequencing and transcriptome sequencing analyses for embryogenic callus (EC), incomplete compact pro-embryogenic cultures (ICpEC) and globular embryos (GE) in an early SE system. At a global level, the DNA 5-methylcytosine content in EC, ICpEC and GE was 24.59, 19.65 and 19.74%, respectively, suggesting a global decrease in DNA methylation from EC to ICpEC and then a slight increase from ICpEC to GE. Differentially methylated region (DMR) analysis showed that hypomethylation mainly occurred in CHH contexts. Gene ontology and Kyoto encyclopedia of genes and genomes analysis of hypomethylated-CHH-DMR-associated genes revealed that zein biosynthesis, fatty acid biosynthesis, circadian rhythm and mitophagy pathways were involved in longan early SE. Expression patterns of DNA methyltransferase and demethylase genes during longan early SE suggested that the decrease in DNA methylation was probably regulated by DNA methyltransferase genes and the DNA demethylase gene REPRESSOR OF SILENCING 1 (ROS1). The correlation between DNA hypomethylation and gene expression revealed that decreased DNA methylation did not cause extensive changes in gene expression during early longan SE and that gene expression may be affected by methylation changes in gene and downstream regions. Inhibiting DNA methylation with 5-azacytidine treatment in EC promoted the formation of GE and enhanced the capability of longan SE. Our results suggest that DNA demethylation has important roles in longan SE development.

scholarly journals Epigenetic Contribution and Genomic Imprinting Dlk1-Dio3 miRNAs in Systemic Lupus Erythematosus

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 680
Author(s):  
Rujuan Dai ◽  
Zhuang Wang ◽  
S. Ansar Ahmed
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Dna Methylation ◽  
Lupus Erythematosus ◽  
Critical Role ◽  
Methylation Status ◽  
Transcriptional Level ◽  
Dna Hypomethylation ◽  
Systemic Lupus ◽  
Multiple Organs ◽  
Genetic Imprinting

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease that afflicts multiple organs, especially kidneys and joints. In addition to genetic predisposition, it is now evident that DNA methylation and microRNAs (miRNAs), the two major epigenetic modifications, are critically involved in the pathogenesis of SLE. DNA methylation regulates promoter accessibility and gene expression at the transcriptional level by adding a methyl group to 5′ cytosine within a CpG dinucleotide. Extensive evidence now supports the importance of DNA hypomethylation in SLE etiology. miRNAs are small, non-protein coding RNAs that play a critical role in the regulation of genome expression. Various studies have identified the signature lupus-related miRNAs and their functional contribution to lupus incidence and progression. In this review, the mutual interaction between DNA methylation and miRNAs regulation in SLE is discussed. Some lupus-associated miRNAs regulate DNA methylation status by targeting the DNA methylation enzymes or methylation pathway-related proteins. On the other hand, DNA hyper- and hypo-methylation are linked with dysregulated miRNAs expression in lupus. Further, we specifically discuss the genetic imprinting Dlk1-Dio3 miRNAs that are subjected to DNA methylation regulation and are dysregulated in several autoimmune diseases, including SLE.

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