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.

scholarly journals Gestational long-term hypoxia induces metabolomic reprogramming and phenotypic transformations in fetal sheep pulmonary arteries

2021 ◽  
Author(s):  
Eric Leslie ◽  
Vanessa Lopez ◽  
Nana A.O. Anti ◽  
Rafael Alvarez ◽  
Isaac Kafeero ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Arteries ◽  
Metabolic Reprogramming ◽  
Persistent Pulmonary Hypertension ◽  
Wall Thickening ◽  
Omega 3 ◽  
Alpha Linolenic Acid ◽  
Fetal Sheep ◽  
Functional Changes

Gestational long-term hypoxia increases the risk of myriad diseases in infants including persistent pulmonary hypertension. Similar to humans, fetal lamb lung development is susceptible to long-term intrauterine hypoxia, with structural and functional changes associated with the development of pulmonary hypertension including pulmonary arterial medial wall thickening and dysregulation of arterial reactivity, which culminates in decreased right ventricular output. To further explore the mechanisms associated with hypoxia-induced aberrations in the fetal sheep lung, we examined the premise that metabolomic changes and functional phenotypic transformations occur due to intrauterine, long-term hypoxia. To address this, we performed electron microscopy, Western immunoblotting, calcium imaging, and metabolomic analyses on pulmonary arteries isolated from near-term fetal lambs that had been exposed to low- or high-altitude (3801 m) hypoxia for the latter 110+ days of gestation. Our results demonstrate that the sarcoplasmic reticulum was swollen with high luminal width and distances to the plasma membrane in the hypoxic group. Hypoxic animals presented with higher endoplasmic reticulum stress and suppressed calcium storage. Metabolically, hypoxia was associated with lower levels of multiple omega-3 polyunsaturated fatty acids and derived lipid mediators (e.g. eicosapentanoic acid, docosahexaenoic acid, alpha-linolenic acid, 5-hydroxyeicosapentaenoic acid (5-HEPE), 12-HEPE, 15-HEPE, prostaglandin E3, and 19(20)-epoxydocosapentaenoic acid), and higher levels of some omega-6 metabolites (p<0.02) including 15-Keto prostaglandin E2 and linoleoylglycerol. Collectively, the results reveal broad evidence for long-term hypoxia-induced metabolic reprogramming and phenotypic transformations in the pulmonary arteries of fetal sheep, conditions that likely contribute to the development of persistent pulmonary hypertension.

scholarly journals Microenvironmental Regulation of Macrophage Transcriptomic and Metabolomic Profiles in Pulmonary Hypertension

2021 ◽  
Vol 12 ◽  
Author(s):  
Min Li ◽  
Suzette Riddle ◽  
Sushil Kumar ◽  
Joanna Poczobutt ◽  
B. Alexandre McKeon ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Macrophage Polarization ◽  
Pulmonary Arteries ◽  
Cell Types ◽  
Metabolic Reprogramming ◽  
Macrophage Phenotype ◽  
Inflammatory Monocytes ◽  
Adventitial Fibroblasts

The recruitment and subsequent polarization of inflammatory monocytes/macrophages in the perivascular regions of pulmonary arteries is a key feature of pulmonary hypertension (PH). However, the mechanisms driving macrophage polarization within the adventitial microenvironment during PH progression remain unclear. We previously established that reciprocal interactions between fibroblasts and macrophages are essential in driving the activated phenotype of both cell types although the signals involved in these interactions remain undefined. We sought to test the hypothesis that adventitial fibroblasts produce a complex array of metabolites and proteins that coordinately direct metabolomic and transcriptomic re-programming of naïve macrophages to recapitulate the pathophysiologic phenotype observed in PH. Media conditioned by pulmonary artery adventitial fibroblasts isolated from pulmonary hypertensive (PH-CM) or age-matched control (CO-CM) calves were used to activate bone marrow derived macrophages. RNA-Seq and mass spectrometry-based metabolomics analyses were performed. Fibroblast conditioned medium from patients with idiopathic pulmonary arterial hypertension or controls were used to validate transcriptional findings. The microenvironment was targeted in vitro using a fibroblast-macrophage co-culture system and in vivo in a mouse model of hypoxia-induced PH. Both CO-CM and PH-CM actively, yet distinctly regulated macrophage transcriptomic and metabolomic profiles. Network integration revealed coordinated rewiring of pro-inflammatory and pro-remodeling gene regulation in concert with altered mitochondrial and intermediary metabolism in response to PH-CM. Pro-inflammation and metabolism are key regulators of macrophage phenotype in vitro, and are closely related to in vivo flow sorted lung interstitial/perivascular macrophages from hypoxic mice. Metabolic changes are accompanied by increased free NADH levels and increased expression of a metabolic sensor and transcriptional co-repressor, C-terminal binding protein 1 (CtBP1), a mechanism shared with adventitial PH-fibroblasts. Targeting the microenvironment created by both cell types with the CtBP1 inhibitor MTOB, inhibited macrophage pro-inflammatory and metabolic re-programming both in vitro and in vivo. In conclusion, coordinated transcriptional and metabolic reprogramming is a critical mechanism regulating macrophage polarization in response to the complex adventitial microenvironment in PH. Targeting the adventitial microenvironment can return activated macrophages toward quiescence and attenuate pathological remodeling that drives PH progression.

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.

Abstract 17224: Metabolic Switch and Redox Imbalance Contributes to Pulmonary Hypertension in Glucose-6-Phosphate Dehydrogenase Deficiency

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Mathews Valuparampil Varghes ◽  
Joel James ◽  
Olga Rafikova ◽  
Ruslan Rafikov
Keyword(s):  
Oxidative Stress ◽  
Pulmonary Hypertension ◽  
G6pd Deficiency ◽  
Mapk Pathway ◽  
Systolic Pressure ◽  
Metabolic Reprogramming ◽  
Pulmonary Vasculature ◽  
Metabolic Switch ◽  
Glucose 6 Phosphate Dehydrogenase ◽  
Deficient Mice

Introduction: Pulmonary hypertension (PH) is a fatal disorder with inadequate therapeutic choices and diminished survival rate with later prognosis. We previously reported that several patients with idiopathic pulmonary arterial hypertension had different types of glucose-6 phosphate dehydrogenase (G6PD) deficiency. G6PD is the key regulator enzyme in the pentose phosphate pathway (PPP) and the only source of NADPH in erythrocytes. However, the pathogenic mechanism of how G6PD deficiency contributes to PH development remains elusive. Hypothesis: We hypothesize that G6PD deficiency-induced PH is mediated through a multifactorial mechanism by increased red blood cell fragility, oxidative stress, and a metabolic switch. Methods: To delineate the contribution of G6PD in PH pathogenesis, we utilized a G6PD knockdown mouse line (11-13 week old) with decreased expression of G6PD (10% from wild-type level). Results: Hemodynamic and histological studies confirmed that G6PD deficient mice developed PH phenotype by an increase in right ventricular systolic pressure (30.08±0.91mmHg; p≤0.001), Fulton index (0.358±0.03; p≤0.01) and pulmonary vascular remodeling. G6PD deficiency resulted in increased free hemoglobin and activation of the p38/MAPK pathway, which we recently reported, induces the development of PH in the sugen/hypoxia model via endothelial barrier dysfunction. Metabolomics analysis of G6PD-deficient mice indicates the switch to alternative metabolic fluxes that feed into PPP, resulting in the upregulation of oxidative stress, fatty acid pathway, and reduction in pyruvate production. Thus, G6PD deficiency did not reduce PPP flux that is important for proliferation but activated collateral pathways at the cost of increased oxidative stress. Indeed, we found upregulation of Myo-inositol oxidase (p≤0.05), reduction in GSH/GSSG ratio (p≤0.01), and increased nitration (p≤0.05) in the lungs of G6PD deficient mice. Increased oxidative stress also results in the activation of PI3K, ERK1/2 and AMPK that contributes to the proliferation of pulmonary vasculature. Conclusions: Based on these results we infer that G6PD deficiency has a multi-modal effect, including hemolysis, metabolic reprogramming, and oxidative stress leading to PH.

Effects of DNA methylation inhibitors and conventional antidepressants on mice behaviour and brain DNA methylation levels

2015 ◽  
Vol 28 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Amanda Juliana Sales ◽  
Sâmia Regiane Lourenço Joca
Keyword(s):  
Dna Methylation ◽  
Neural Plasticity ◽  
Dna Methyltransferase ◽  
Antidepressant Drugs ◽  
Brain Regions ◽  
Dna Methyltransferase Inhibitors ◽  
Behavioural Effects ◽  
Expression Of Genes ◽  
Induced Changes ◽  
Dna Methylation Inhibitors

ObjectiveStress increases DNA methylation and decreases the expression of genes involved in neural plasticity, while treatment with DNA methyltransferase inhibitors (DNMTi) increases gene expression and induces antidepressant-like effects in preclinical models. Therefore, the aim of the present work was to further investigate the potential antidepressant-like effect induced by DNMTi by evaluating the behavioural effects induced by associating DNMTi treatment with conventional antidepressant drugs in mice submitted to the forced swimming test (FST). In addition, brain levels of DNA methylation were also investigated.MethodsMice received systemic injections of 5-aza-2'-deoxycytidine (5-AzaD, 0.1, 0.2 mg/kg), RG108 (0.1, 0.2, 0.4 mg/kg), desipramine (DES, 2.5, 5, 10 mg/kg) or fluoxetine (FLX, 5, 10, 20, 30 mg/kg) and were submitted to the FST or to the open field test (OFT). Additional groups received a combination of subeffective doses of 5-AzaD or RG108 (DNMTi) with subeffective doses of DES or FLX (antidepressants).ResultsSubeffective doses of RG108 (0.1 mg/kg) or 5-AzaD (0.1mg/kg) in association with subeffective doses of DES (2.5 mg/kg) or FLX (10 mg/kg) induced significant antidepressant-like effects. Effective doses of RG108 (0.2 mg/kg), 5-AzaD (0.2 mg/kg), DES (10 mg/kg) and FLX (20 mg/kg) atenuated stress-induced changes in DNA methylation levels in the hippocampus and prefrontal cortex. None of the treatments induced locomotor effects in the OFT.ConclusionThese results suggest that DNMTi potentiate the behavioural effects of antidepressant drugs in the FST and that antidepressants, as well as DNMTi, are able to modulate stress-induced changes in DNA methylation in brain regions closely associated with the neurobiology of depression.

scholarly journals Hypoxia-induced glucose-6-phosphate dehydrogenase overexpression and -activation in pulmonary artery smooth muscle cells: implication in pulmonary hypertension

2015 ◽  
Vol 308 (3) ◽  
pp. L287-L300 ◽  
Author(s):  
Sukrutha Chettimada ◽  
Rakhee Gupte ◽  
Dhwajbahadur Rawat ◽  
Sarah A. Gebb ◽  
Ivan F. McMurtry ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Pulmonary Arteries ◽  
Pentose Phosphate ◽  
Arterial Remodeling ◽  
Altered Glucose ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle ◽  
Glucose 6 Phosphate Dehydrogenase

Severe pulmonary hypertension is a debilitating disease with an alarmingly low 5-yr life expectancy. Hypoxia, one of the causes of pulmonary hypertension, elicits constriction and remodeling of the pulmonary arteries. We now know that pulmonary arterial remodeling is a consequence of hyperplasia and hypertrophy of pulmonary artery smooth muscle (PASM), endothelial, myofibroblast, and stem cells. However, our knowledge about the mechanisms that cause these cells to proliferate and hypertrophy in response to hypoxic stimuli is still incomplete, and, hence, the treatment for severe pulmonary arterial hypertension is inadequate. Here we demonstrate that the activity and expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, are increased in hypoxic PASM cells and in lungs of chronic hypoxic rats. G6PD overexpression and -activation is stimulated by H2O2. Increased G6PD activity contributes to PASM cell proliferation by increasing Sp1 and hypoxia-inducible factor 1α (HIF-1α), which directs the cells to synthesize less contractile (myocardin and SM22α) and more proliferative (cyclin A and phospho-histone H3) proteins. G6PD inhibition with dehydroepiandrosterone increased myocardin expression in remodeled pulmonary arteries of moderate and severe pulmonary hypertensive rats. These observations suggest that altered glucose metabolism and G6PD overactivation play a key role in switching the PASM cells from the contractile to synthetic phenotype by increasing Sp1 and HIF-1α, which suppresses myocardin, a key cofactor that maintains smooth muscle cell in contractile state, and increasing hypoxia-induced PASM cell growth, and hence contribute to pulmonary arterial remodeling and pathogenesis of pulmonary hypertension.

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.

Pulmonary Endarterectomy: Assessment of Operability, Surgical Description, and Post-op Care

2014 ◽  
Vol 12 (4) ◽  
pp. 186-192 ◽  
Author(s):  
David Poch ◽  
Victor Pretorius
Keyword(s):  
Pulmonary Hypertension ◽  
Pulmonary Artery ◽  
Pulmonary Artery Pressure ◽  
Pulmonary Arteries ◽  
Chronic Thromboembolic Pulmonary Hypertension ◽  
Pulmonary Artery Wedge Pressure ◽  
Pulmonary Endarterectomy ◽  
Pulmonary Thromboendarterectomy ◽  
Thromboembolic Pulmonary Hypertension ◽  
Wedge Pressure

Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as a mean pulmonary artery pressure ≥25 mm Hg and pulmonary artery wedge pressure ≤15 mm Hg in the presence of occlusive thrombi within the pulmonary arteries. Surgical pulmonary thromboendarterectomy (PTE) is considered the best treatment option for CTEPH.

scholarly journals Oxygen-Sensitivity and Pulmonary Selectivity of Vasodilators as Potential Drugs for Pulmonary Hypertension

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 155
Author(s):  
Daniel Morales-Cano ◽  
Bianca Barreira ◽  
Beatriz De Olaiz Navarro ◽  
María Callejo ◽  
Gema Mondejar-Parreño ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Gas Exchange ◽  
Pulmonary Circulation ◽  
Pulmonary Arteries ◽  
Blood Perfusion ◽  
Mesenteric Arteries ◽  
Oxygen Sensitivity ◽  
Low Oxygen ◽  
Oxygen Selectivity

Current approved therapies for pulmonary hypertension (PH) aim to restore the balance between endothelial mediators in the pulmonary circulation. These drugs may exert vasodilator effects on poorly oxygenated vessels. This may lead to the derivation of blood perfusion towards low ventilated alveoli, i.e., producing ventilation-perfusion mismatch, with detrimental effects on gas exchange. The aim of this study is to analyze the oxygen-sensitivity in vitro of 25 drugs currently used or potentially useful for PH. Additionally, the study analyses the effectiveness of these vasodilators in the pulmonary vs. the systemic vessels. Vasodilator responses were recorded in pulmonary arteries (PA) and mesenteric arteries (MA) from rats and in human PA in a wire myograph under different oxygen concentrations. None of the studied drugs showed oxygen selectivity, being equally or more effective as vasodilators under conditions of low oxygen as compared to high oxygen levels. The drugs studied showed low pulmonary selectivity, being equally or more effective as vasodilators in systemic than in PA. A similar behavior was observed for the members within each drug family. In conclusion, none of the drugs showed optimal vasodilator profile, which may limit their therapeutic efficacy in PH.

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