scholarly journals Mechanisms Contributing to the Dysregulation of miRNA-124 in Pulmonary Hypertension

2021 ◽  
Vol 22 (8) ◽  
pp. 3852
Author(s):  
Hui Zhang ◽  
Aya Laux ◽  
Kurt R. Stenmark ◽  
Cheng-Jun Hu
Keyword(s):  
Pulmonary Hypertension ◽  
Gene Transcription ◽  
Chromatin Structure ◽  
Hdac Inhibitors ◽  
Open Chromatin ◽  
Vascular Cells ◽  
Aberrant Expression ◽  
Chromatin Mark ◽  
Expression Of Genes ◽  
Chronic Pulmonary Hypertension

Chronic pulmonary hypertension (PH) is a fatal disease characterized by the persistent activation of pulmonary vascular cells that exhibit aberrant expression of genes including miRNAs. We and others reported that decreased levels of mature microRNA-124 (miR-124) plays an important role in modulating the activated phenotype of pulmonary vascular cells and HDAC inhibitors (HDACi) can restore the levels of mature miR-124 and reverse the persistently activated phenotype of PH vascular cells. In this study, we sought to determine the mechanisms contributing to reduced levels of miRNAs, as well as how HDACi restores the levels of reduced miRNA in PH vascular cells. We found that pulmonary artery fibroblasts isolated from IPAH patients (PH-Fibs) exhibit reduced levels of mature miR-124 and several other miRNAs including let-7i, miR-224, and miR-210, and that these reduced levels can be restored by HDACi. Using miR-124 expression in human PH-Fibs as a model, we determined that reduced miR-124 gene transcription, not decreased expression of miRNA processing genes, is responsible for reduced levels of mature miR-124 in human PH-Fibs. Using both DNase I Sensitivity and chromatin immunoprecipitation assays, we found that the miR-124-1 gene exhibits a more condensed chromatin structure in human PH-Fibs, compared to corresponding controls. HDACi relaxed miR-124-1 chromatin structure, evidenced by increased levels of the open chromatin mark H3K27Ac, but decreased levels of closed chromatin mark H3K27Me3. Most importantly, the delivery of histone acetyltransferase (HAT) via CRISPR-dCas9-HAT and guiding RNAs to the promoter of the miR-124-1 gene increased miR-124-1 gene transcription. Thus, our data indicate epigenetic events play important role in controlling miR-124 and likely other miRNA levels and epigenetic regulators such as HDACs appear to be promising therapeutic targets for chronic PH.

scholarly journals Inhibitors of Histone Deacetylase and DNA Methyltransferase Synergistically Activate the Methylated Metallothionein I Promoter by Activating the Transcription Factor MTF-1 and Forming an Open Chromatin Structure

2002 ◽  
Vol 22 (23) ◽  
pp. 8302-8319 ◽  
Author(s):  
Kalpana Ghoshal ◽  
Jharna Datta ◽  
Sarmila Majumder ◽  
Shoumei Bai ◽  
Xiaocheng Dong ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Histone Deacetylase ◽  
Chromatin Structure ◽  
Dna Methyltransferase ◽  
Combined Treatment ◽  
Hdac Inhibitors ◽  
Prolonged Treatment ◽  
Open Chromatin ◽  
Chip Assay

ABSTRACT Inhibitors of DNA methyltransferase (Dnmt) and histone deacetylases (HDAC) synergistically activate the methylated metallothionein I gene (MT-I) promoter in mouse lymphosarcoma cells. The cooperative effect of these two classes of inhibitors on MT-I promoter activity was robust following demethylation of only a few CpG dinucleotides by brief exposure to 5-azacytidine (5-AzaC) but persisted even after prolonged treatment with the nucleoside analog. HDAC inhibitors (trichostatin A [TSA] and depsipeptide) either alone or in combination with 5-AzaC did not facilitate demethylation of the MT-I promoter. Treatment of cells with HDAC inhibitors increased accumulation of multiply acetylated forms of H3 and H4 histones that remained unaffected after treatment with 5-AzaC. Chromatin immunoprecipitation (ChIP) assay showed increased association of acetylated histone H4 and lysine 9 (K9)-acetyl H3 with the MT-I promoter after treatment with TSA, which was not affected following treatment with 5-AzaC. In contrast, the association of K9-methyl histone H3 with the MT-I promoter decreased significantly after treatment with 5-AzaC and TSA. ChIP assay with antibodies specific for methyl-CpG binding proteins (MBDs) demonstrated that only methyl-CpG binding protein 2 (MeCP2) was associated with the MT-I promoter, which was significantly enhanced after TSA treatment. Association of histone deacetylase 1 (HDAC1) with the promoter decreased after treatment with TSA or 5-AzaC and was abolished after treatment with both inhibitors. Among the DNA methyltransferases, both Dnmt1 and Dnmt3a were associated with the MT-I promoter in the lymphosarcoma cells, and association of Dnmt1 decreased with time after treatment with 5-AzaC. Treatment of these cells with HDAC inhibitors also increased expression of the MTF-1 (metal transcription factor-1) gene as well as its DNA binding activity. In vivo genomic footprinting studies demonstrated increased occupancy of MTF-1 to metal response elements of the MT-I promoter after treatment with both inhibitors. Analysis of the promoter by mapping with restriction enzymes in vivo showed that the MT-I promoter attained a more open chromatin structure after combined treatment with 5-AzaC and TSA as opposed to treatment with either agent alone. These results implicate involvement of multifarious factors including modified histones, MBDs, and Dnmts in silencing the methylated MT-I promoter in lymphosarcoma cells. The synergistic activation of this promoter by these two types of inhibitors is due to demethylation of the promoter and altered association of different factors that leads to reorganization of the chromatin and the resultant increase in accessibility of the promoter to the activated transcription factor MTF-1.

scholarly journals RNA-Binding Proteins in Pulmonary Hypertension

2020 ◽  
Vol 21 (11) ◽  
pp. 3757 ◽  
Author(s):  
Hui Zhang ◽  
R. Dale Brown ◽  
Kurt R. Stenmark ◽  
Cheng-Jun Hu
Keyword(s):  
Gene Expression ◽  
Pulmonary Hypertension ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Current Knowledge ◽  
Critical Role ◽  
Apoptosis Resistance ◽  
Aberrant Expression ◽  
Expression Of Genes

Pulmonary hypertension (PH) is a life-threatening disease characterized by significant vascular remodeling and aberrant expression of genes involved in inflammation, apoptosis resistance, proliferation, and metabolism. Effective therapeutic strategies are limited, as mechanisms underlying PH pathophysiology, especially abnormal expression of genes, remain unclear. Most PH studies on gene expression have focused on gene transcription. However, post-transcriptional alterations have been shown to play a critical role in inflammation and metabolic changes in diseases such as cancer and systemic cardiovascular diseases. In these diseases, RNA-binding proteins (RBPs) have been recognized as important regulators of aberrant gene expression via post-transcriptional regulation; however, their role in PH is less clear. Identifying RBPs in PH is of great importance to better understand PH pathophysiology and to identify new targets for PH treatment. In this manuscript, we review the current knowledge on the role of dysregulated RBPs in abnormal mRNA gene expression as well as aberrant non-coding RNA processing and expression (e.g., miRNAs) in PH.

scholarly journals Hypoxic activation of glucose-6-phosphate dehydrogenase controls the expression of genes involved in the pathogenesis of pulmonary hypertension through the regulation of DNA methylation

2020 ◽  
Vol 318 (4) ◽  
pp. L773-L786
Author(s):  
Sachindra Raj Joshi ◽  
Atsushi Kitagawa ◽  
Christina Jacob ◽  
Ryota Hashimoto ◽  
Vidhi Dhagia ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Metabolic Reprogramming ◽  
Aberrant Expression ◽  
Expression Of Genes ◽  
Normal Individuals ◽  
Induced Changes ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Aberrant Gene

Metabolic reprogramming is considered important in the pathogenesis of the occlusive vasculopathy observed in pulmonary hypertension (PH). However, the mechanisms that link reprogrammed metabolism to aberrant expression of genes, which modulate functional phenotypes of cells in PH, remain enigmatic. Herein, we demonstrate that, in mice, hypoxia-induced PH was prevented by glucose-6-phosphate dehydrogenase deficiency (G6PDDef), and further show that established severe PH in Cyp2c44−/− mice was attenuated by knockdown with G6PD shRNA or by G6PD inhibition with an inhibitor (N-ethyl-N′-[(3β,5α)-17-oxoandrostan-3-yl]urea, NEOU). Mechanistically, G6PDDef, knockdown and inhibition in lungs: 1) reduced hypoxia-induced changes in cytoplasmic and mitochondrial metabolism, 2) increased expression of Tet methylcytosine dioxygenase 2 ( Tet2) gene, and 3) upregulated expression of the coding genes and long noncoding (lnc) RNA Pint, which inhibits cell growth, by hypomethylating the promoter flanking region downstream of the transcription start site. These results suggest functional TET2 is required for G6PD inhibition to increase gene expression and to reverse hypoxia-induced PH in mice. Furthermore, the inhibitor of G6PD activity (NEOU) decreased metabolic reprogramming, upregulated TET2 and lncPINT, and inhibited growth of control and diseased smooth muscle cells isolated from pulmonary arteries of normal individuals and idiopathic-PAH patients, respectively. Collectively, these findings demonstrate a previously unrecognized function for G6PD as a regulator of DNA methylation. These findings further suggest that G6PD acts as a link between reprogrammed metabolism and aberrant gene regulation and plays a crucial role in regulating the phenotype of cells implicated in the pathogenesis of PH, a debilitating disorder with a high mortality rate.

The role of microRNA-21 in the onset and progression of cancer

2021 ◽  
Author(s):  
Ashutosh Singh ◽  
Ashutosh Kumar Singh ◽  
Rajanish Giri ◽  
Dhruv Kumar ◽  
Rohit Sharma ◽  
...  
Keyword(s):  
Cancer Detection ◽  
Tumor Suppressor Genes ◽  
Noncoding Rna ◽  
Early Cancer ◽  
Cancer Resistance ◽  
Aberrant Expression ◽  
Small Noncoding Rna ◽  
Expression Of Genes ◽  
Oncogenic Property

MicroRNAs (miRNAs), a class of small noncoding RNA, posttranscriptionally regulate the expression of genes. Aberrant expression of miRNA is reported in various types of cancer. Since the first report of oncomiR-21 involvement in the glioma, its upregulation was reported in multiple cancers and was allied with high oncogenic property. In addition to the downregulation of tumor suppressor genes, the miR-21 is also associated with cancer resistance to various chemotherapy. The recent research is appraising miR-21 as a promising cancer target and biomarker for early cancer detection. In this review, we briefly explain the biogenesis and regulation of miR-21 in cancer cells. Additionally, the review features the assorted genes/pathways regulated by the miR-21 in various cancer and cancer stem cells.

scholarly journals HDAC2 Is Involved in the Regulation of BRN3A in Melanocytes and Melanoma

2022 ◽  
Vol 23 (2) ◽  
pp. 849
Author(s):  
Markus V. Heppt ◽  
Anja Wessely ◽  
Eva Hornig ◽  
Claudia Kammerbauer ◽  
Saskia A. Graf ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Histone Acetyltransferase ◽  
Trichostatin A ◽  
Hdac Inhibitors ◽  
Melanoma Cells ◽  
Distal Enhancer ◽  
Aberrant Expression ◽  
Expression Levels ◽  
Epigenetic Regulator ◽  
Class I Hdacs

The neural crest transcription factor BRN3A is essential for the proliferation and survival of melanoma cells. It is frequently expressed in melanoma but not in normal melanocytes or benign nevi. The mechanisms underlying the aberrant expression of BRN3A are unknown. Here, we investigated the epigenetic regulation of BRN3A in melanocytes and melanoma cell lines treated with DNA methyltransferase (DNMT), histone acetyltransferase (HAT), and histone deacetylase (HDAC) inhibitors. DNMT and HAT inhibition did not significantly alter BRN3A expression levels, whereas panHDAC inhibition by trichostatin A led to increased expression. Treatment with the isoform-specific HDAC inhibitor mocetinostat, but not with PCI-34051, also increased BRN3A expression levels, suggesting that class I HDACs HDAC1, HDAC2, and HDAC3, and class IV HDAC11, were involved in the regulation of BRN3A expression. Transient silencing of HDACs 1, 2, 3, and 11 by siRNAs revealed that, specifically, HDAC2 inhibition was able to increase BRN3A expression. ChIP-Seq analysis uncovered that HDAC2 inhibition specifically increased H3K27ac levels at a distal enhancer region of the BRN3A gene. Altogether, our data suggest that HDAC2 is a key epigenetic regulator of BRN3A in melanocytes and melanoma cells. These results highlight the importance of epigenetic mechanisms in regulating melanoma oncogenes.

scholarly journals Analysis of CNV in the Genomes of the Marrow Cells of the Patients with AML Revealed That High Numbers of Aberrations Associate with Better Survival and Deletions with the Aberrant Expression of CD19 in the Leukemic Blasts

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5164-5164
Author(s):  
Emilia Jaskula ◽  
Janusz Lange ◽  
Monika Mordak-Domagala ◽  
Mariola Sedzimirska ◽  
Marta Lemieszewska ◽  
...  
Keyword(s):  
Chromatin Structure ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Hidden Markov ◽  
Aberrant Expression ◽  
Knowing That ◽  
Segmentation Algorithms ◽  
The Mean ◽  
Cd19 Expression ◽  
Marrow Cells

In our previous study (Jaskula et al., Blood 2017 130:1420) we reported that the number of CNVs within the KANSL1 gene was associated with the phenotype of AML. In the present study we looked at the presence of CNV across the whole genome. One hundred and twenty seven AML patients (diagnosed according to the FAB/WHO criteria, F/M=62/65, age median: 57, range: 21 - 84 years) were included to the present study. The patients were genetically analysed including GTG karyotyping and/or FISH for X or Y deletion, inv (3), -5/5q-, -7/7q-,+8, MLL, RUNX1, PML/RARA or RARA, inv(16). In all patients the microarray analysis of the bone marrow cells having blasts cells (median value 56%) at diagnosis Agilent - Catalog Agilent Cancer CGH+SNP 180K (74 patients) or Roche - WG Catalog NimbleGene 12x270K (53 patients) microarrays were employed and the results were analysed with the use the Partek software employing the Partek Hidden Markov Model (HMM) and segmentation algorithms. Results: The number of CNV in M0 AML marrow cells was significantly lower (median: 0 aberration), as compared to secondary to MDS AML (median: 4.5 aberrations, p=0.006). Patients with AML subtypes from M1 to M6 had higher number of CNV amplifications (median: 2) as compared to the patients with minimally differentiated blasts (M0, median: 0 amplifications, p=0.030). Knowing that (i) changes in the chromatin structure may be associated with the CNV prevalence within the genome (Gheldof et al., PLoS One. 2013 Nov 12;8(11):e79973) and (ii) the aberrant expression of CD19 in AML blasts results from the chromatin structure variations (Walter et al., Oncogene. 2010 May 20;29(20):2927-37) we looked at the presence of association between the numbers of CNV and the presence of the aberrant CD19 expression in the leukemic blasts. It appeared that 11 AML patients having aberrant expression of CD19 (within whom 4 had t(8:21)) had more frequently CNV deletions than those lacking this aberrant expression (median: 2 vs 1 deletions, p=0.018, HMM algorithm). Having the survival curves of the patients plotted accordingly to the high and low numbers of CNV, the situation is more complex and shows that: the patients having higher numbers of CNV aberrations (exceeding the mean of the whole group +SD) enjoyed better survival (20% vs 11%, p=0.090) when segmentation algorithm was employed. HMM analysis also suggested that the higher values of CNV (amplifications, exceeding the mean of the whole group +SD) was associated with better 5-year survival as compared to those with low numbers (42% vs 20%, ns). The aberrant expression of CD19 analysis was associated with higher numbers of deletions (see above) and with better 5-year survival than those lacking this aberrant expression (45% vs 20%, p=0.064). In conclusion, the prevalence of CNV within the genome shapes the phenotype of the leukemia and facilitates the survival. Disclosures No relevant conflicts of interest to declare.

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