Abstract 15544: Implication of the Histone Methyltransferase “G9a” in Pulmonary Arterial Hypertension

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Charifa awada ◽  
Karima Habbout ◽  
Valerie Nadeau ◽  
Sandra Breuils-Bonnet ◽  
Roxane Paulin ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Histone Methyltransferase ◽  
Sequencing Analysis ◽  
Apoptosis Resistance ◽  
Cancer Pathogenesis ◽  
Therapeutic Benefits ◽  
Pulmonary Arterial

Rationale: Pulmonary arterial hypertension (PAH) is a cardiopulmonary disorder characterized by elevation of pulmonary arterial (PA) pressure and premature death. PA smooth muscle cells (PASMCs) from PAH patients present a cancer-like hyperproliferative and apoptosis-resistant phenotype contributing to remodeling of distal PAs. Although epigenetic alterations contribute to PAH development, one important challenge is defining which genes are the drivers . A growing body of literature points to the role of an epigenetic factor called G9a in cancer pathogenesis. Indeed, G9a is a histone methyltransferase overexpressed in many cancers promoting cell proliferation and survival. Given the similarities between PAH and cancer, it is of interest to determine whether G9a is implicated in PAH. We thus hypothesized that G9a inhibition reduces the pro-proliferative and apoptosis resistance phenotype of PAH-PASMCs. Methods and Results: Using Western blot (WB) and immunofluorescence (IF), we showed that G9a is overexpressed in distal PAs and isolated PASMCs from PAH patients (n= 6-14, p<0.01). Similarly, G9a was increased (WB and IF, p<0.05) in two models mimicking the disease; namely the monocrotaline rat and mice exposed to chronic hypoxia. In vitro, we found that pharmacological inhibition of G9a using BIX01294 and UNC0642 reduces PAH-PASMC proliferation (Ki67 and EdU assays, p<0.001) and survival (Annexin V assay p<0.001). Through RNA sequencing analysis conducted in PAH-PASMCs treated or not with BIX01294, we found that upregulated differentially expressed genes (DEGs) were enriched in cholesterol biosynthesis, autophagy-lysosome and ER stress-induced apoptotic pathways. However, downregulated DEGs were involved in cell cycle and fibrosis-related processes. Consistently, inhibition of G9a generates numerous cytoplasmic vacuoles positive for LC3-II and p62 (WB, IF), thus suggesting that the inhibition of G9a induces cell death by altering cholesterol metabolism-dependent autophagy. Conclusion: We showed for the first time that G9a is overexpressed in PAH contributing to the pro-proliferative and anti-apoptotic phenotype of PAH-PASMCs. Current experiments aim to determine whether G9a inhibition provides therapeutic benefits in PAH.

scholarly journals Epigenetic Inheritance Underlying Pulmonary Arterial Hypertension

2019 ◽  
Vol 39 (4) ◽  
pp. 653-664 ◽  
Author(s):  
Claudio Napoli ◽  
Giuditta Benincasa ◽  
Joseph Loscalzo
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Vascular Remodeling ◽  
Disease Onset ◽  
Later Life ◽  
Epigenetic Changes ◽  
Apoptosis Resistance ◽  
Integrated Network ◽  
Mesenchymal Transition ◽  
Pulmonary Arterial

In pulmonary arterial hypertension (PAH), the Warburg effect (glycolytic shift) and mitochondrial fission are determinants of phenotype alterations characteristic of the disease, such as proliferation, apoptosis resistance, migration, endothelial-mesenchymal transition, and extracellular matrix stiffness. Current therapies, focusing largely on vasodilation and antithrombotic protection, do not restore these aberrant phenotypes suggesting that additional pathways need be targeted. The multifactorial nature of PAH suggests epigenetic changes as potential determinants of vascular remodeling. Transgenerational epigenetic changes induced by hypoxia can result in permanent changes early in fetal development increasing PAH risk in adulthood. Unlike genetic mutations, epigenetic changes are pharmacologically reversible, making them an attractive target as therapeutic strategies for PAH. This review offers a landscape of the most current clinical, epigenetic-sensitive changes contributing to PAH vascular remodeling both in early and later life, with a focus on a network medicine strategy. Furthermore, we discuss the importance of the application (from morphogenesis to disease onset) of molecular network-based algorithms to dissect PAH molecular pathobiology. Additionally, we suggest an integrated network-based program for clinical disease gene discovery that may reveal novel biomarkers and novel disease targets, thus offering a truly innovative path toward redefining and treating PAH, as well as facilitating the trajectory of a comprehensive precision medicine approach to PAH.

Abstract 14257: Endothelial SOX17 Deficiency Induces Pulmonary Arterial Hypertension

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Zhiyu Dai ◽  
Dan Yi ◽  
BIN LIU ◽  
Shuai Li
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Vascular Remodeling ◽  
Molecular Mechanisms ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Sequencing Analysis ◽  
Pulmonary Arterial

Introduction: Pulmonary arterial hypertension (PAH) is a disaster disease characterized by obliterative vascular remodeling and persistent increase of vascular resistance, leading to right heart failure and premature death. Understanding the cellular and molecular mechanisms will help develop novel therapeutic approaches for PAH patients. Hypothesis: Human genome-wide association studies identified that SOX17 locus variants are associated with PAH. SOX17 mutation is also found in patients with PAH. We hypothesis that endothelial SOX17 deficiency contributes to the pathogenesis of PAH. Methods: Mice with EndoSCL-CreERT mediated deletion of Sox17 ( Sox17 iCKO ) were generated. Sox17 iCKO and Sox17 f/f mice after tamoxifen injection were incubated with hypoxia (10% O 2 ) for 3 weeks to induced PAH. Hemodynamics and histological examination were measured to determine the PAH phenotypes and vascular remodeling. EC proliferation and apoptosis were assessed in SiRNA-mediated SOX17 knockdown in human lung microvascular endothelial cells (hLMVECs). The RNA-sequencing analysis was performed to understand the molecular mechanisms of SOX17 deficiency in ECs. Results: Sox17 iCKO mice exhibited exaggerative PAH evident by the increase of RVSP and RV hypertrophy after hypoxia treatment compared to Sox17 f/f WT mice. SOX17 knockdown in hLMVECs induced cell proliferation and reduced starvation-induced apoptosis. RNA-seq analysis and DAVID pathway analysis demonstrated that there was dysregulation of cell proliferation-related genes, which are enriched in the pathways related to cell cycle, cell division, and mitotic cell cycle. Transcriptional factor, target, and motif discovery analysis of the dysregulated gene set revealed the involvement of transcriptional factors FOXM1 and E2F1. siRNA mediated knockdown of E2F1 but not FOXM1 normalized SOX17 deficiency-induced hLMVECs proliferation and anti-apoptosis. Conclusions: Our study demonstrated that endothelial SOX17 deficiency exaggerates hypoxia-induced PAH. Loss of SOX17 promotes EC proliferation and anti-apoptosis via the upregulation of transcription factor E2F1.

Combination Pharmacotherapy in the Treatment of Pulmonary Arterial Hypertension

2013 ◽  
Vol 26 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Kimberly L. Tackett ◽  
Gregory V. Stajich
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Combination Therapy ◽  
Arterial Hypertension ◽  
Therapeutic Option ◽  
Symptom Control ◽  
Right Ventricular Dysfunction ◽  
Functional Class ◽  
Current Therapy ◽  
Therapeutic Benefits ◽  
Pulmonary Arterial

Pulmonary arterial hypertension (PAH) is a disorder of the small pulmonary arteries characterized by progressive fibrotic and proliferative changes that result in an increased pulmonary vascular resistance. It is a progressive and debilitating disease that leads to right ventricular dysfunction, impairment in activity tolerance and eventually right-sided heart failure, and premature death. The treatment goals for PAH include improvement in symptoms, improvement in functional class and exercise class, decreased morbidity, and preventing mortality. Combination therapy in the treatment of PAH is an emerging therapeutic option. Combining therapies with differing mechanisms of action will maximize therapeutic benefits such as symptom control and increased rate of survival. The updated 2007 American College of Chest Physicians evidence-based clinical practice guidelines recommend combination therapy in functional classes III and IV if there is no improvement with current therapy or if there is deterioration in class. PAH monotherapy has been shown to improve symptoms, but the patients’ hemodynamic parameters may not be normalized, leading to further pulmonary vascular remodeling. Combination therapy offers an additional option for those patients who are unable to stabilize on monotherapy.

scholarly journals Therapeutic Benefits of Induced Pluripotent Stem Cells in Monocrotaline-Induced Pulmonary Arterial Hypertension

PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0142476 ◽  
Author(s):  
Wei-Chun Huang ◽  
Meng-Wei Ke ◽  
Chin-Chang Cheng ◽  
Shih-Hwa Chiou ◽  
Shue-Ren Wann ◽  
...  
Keyword(s):  
Stem Cells ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Therapeutic Benefits ◽  
Pulmonary Arterial ◽  
Induced Pluripotent

Abstract 13972: Dexmedetomidine Ameliorates Monocrotaline Induced Pulmonary Arterial Hypertension in Rats

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yusuke Kajikawa ◽  
Susumu Hosokawa ◽  
Kenji Wakabayashi ◽  
Yasuhiro Maejima ◽  
Mitsuaki Isobe ◽  
...  
Keyword(s):  
Survival Rate ◽  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Inflammatory Responses ◽  
Systolic Pressure ◽  
Sprague Dawley ◽  
Apoptosis Resistance ◽  
Ventricular Systolic Pressure ◽  
Significant Difference ◽  
Pulmonary Arterial

[Introduction] Pulmonary arterial hypertension (PAH) is characterized by increased proliferation and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs). Dexmedetomidine (DEX) is a selective α2-aderenergic receptor agonist that is used for sedation in clinical practice. It has been reported that DEX inhibits inflammatory responses through cytokines, such as TNF-alpha, IL-6. Furthermore other reports show that G-protein-coupled receptors (GPCRs) are regulated by β-arrestins, which are also involved with inflammation. [Hypothesis] DEX ameliorates monocrotaline (MCT)-induced PAH in rats by its anti-inflammatory effect. [Methods] We treated 6 weeks-old male Sprague-Dawley rats with a single 60mg/kg intraperitoneal injection of MCT. After 14 days of injection, one group of rats was started to administer dexmedetomidine (dose: 2μg/kg/hour, MCT+DEX group) continuously using osmotic pumps, the other group was not treated with DEX (MCT group). We performed physiological examination and cardiac catheterization to measure right ventricular systolic pressure (RVSP) at day 23. [Results] Both RVSP and survival rate of rats in MCT+DEX group markedly improved compared with those in MCT group (RVSP; 38mmHg±11mmHg vs 91mmHg±6mmHg, survival rate; 42% vs 0% at day 30). In histological analysis, DEX reduced the medial hypertrophy of pulmonary arterioles, and decreased phosphorylated-NF-kB p65 (p-p65) positive PASMCs in MCT+DEX group compared with those of MCT group. In addition, DEX suppressed PASMCs proliferation with PCNA staining, and induced apoptosis of PASMCs with TUNEL assay. Then we examined the involvement of β-arrestins in PAH. It showed that βarrestin1 expressions reduced in MCT group compared with that of MCT+DEX group with western blotting and immunohistochemistry. However β-arrestin2 expressions had no significant difference between the two groups. [Conclusions] DEX ameliorates MCT-induced PAH in rats, one of the mechanism of which may be NF-kB inhibition through β-arrestin1. DEX can be a new therapeutic tool for PAH.

scholarly journals Recent advances in targeting the prostacyclin pathway in pulmonary arterial hypertension

2015 ◽  
Vol 24 (138) ◽  
pp. 630-641 ◽  
Author(s):  
Irene M. Lang ◽  
Sean P. Gaine
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Severe Disease ◽  
Subcutaneous Administration ◽  
Functional Class ◽  
Arterial Blood Flow ◽  
Arterial Blood ◽  
Therapeutic Benefits ◽  
Embolism And Thrombosis ◽  
Pulmonary Arterial

Pulmonary arterial hypertension (PAH) is a severe disease characterised by increased pulmonary vascular resistance, which leads to restricted pulmonary arterial blood flow and elevated pulmonary arterial pressure. In patients with PAH, pulmonary concentrations of prostacyclin, a prostanoid that targets several receptors including the IP prostacyclin receptor, are reduced. To redress this balance, epoprostenol, a synthetic prostacyclin, or analogues of prostacyclin have been given therapeutically. These therapies improve exercise capacity, functional class and haemodynamic parameters. In addition, epoprostenol improves survival among patients with PAH. Despite their therapeutic benefits, treatments that target the prostacyclin pathway are underused. One key factor is their requirement for parenteral administration: continuous intravenous administration can lead to embolism and thrombosis; subcutaneous administration is associated with infusion-site pain; and inhalation is time consuming, requiring multiple daily administrations. Nevertheless, targeting the prostacyclin pathway is an important strategy for the management of PAH. The development of oral therapies for this pathway, as well as more user-friendly delivery devices, may alleviate some of the inconveniences. Continued improvements in therapeutic options will enable more patients with PAH to receive medication targeting the prostacyclin pathway.

scholarly journals Regulation of The Methylation and Expression Levels of the BMPR2 Gene by SIN3a As A Novel Therapeutic Mechanism in Pulmonary Arterial Hypertension

Circulation ◽  
2021 ◽  
Author(s):  
Malik Bisserier ◽  
Prabhu Mathiyalagan ◽  
Shihong Zhang ◽  
Firas Elmastour ◽  
Peter Dorfmüller ◽  
...  
Keyword(s):  
Pulmonary Arterial Hypertension ◽  
Arterial Hypertension ◽  
Transcriptional Regulator ◽  
Ctcf Binding ◽  
Sequencing Analysis ◽  
Epigenetic Mechanisms ◽  
Rodent Models ◽  
Virus Serotype ◽  
Pulmonary Arterial

Background: Epigenetic mechanisms are critical in the pathogenesis of pulmonary arterial hypertension (PAH). Previous studies have suggested that hypermethylation of the Bone Morphogenetic Protein Receptor Type 2 (BMPR2) promoter is associated with BMPR2 downregulation and progression of PAH. Here, we investigated for the first time the role of Switch-Independent 3a (SIN3a), a transcriptional regulator, in the epigenetic mechanisms underlying hypermethylation of BMPR2 in the pathogenesis of PAH. Methods: We used lung samples from PAH patients and non-PAH controls, preclinical mouse and rat PAH models, and human pulmonary arterial smooth muscle cells (hPASMC). Expression of SIN3a was modulated using a lentiviral vector or a siRNA in vitro and a specific Adeno-Associated Virus serotype 1 (AAV1) or a lentivirus encoding for human SIN3a in vivo . Results: SIN3a is a known transcriptional regulator; however, its role in cardiovascular diseases, especially PAH, is unknown. Interestingly, we detected a dysregulation of SIN3 expression in patients and in rodent models, which is strongly associated with decreased BMPR2 expression. SIN3a is known to regulate epigenetic changes. Therefore, we tested its role in the regulation of BMPR2 and found that BMPR2 is regulated by SIN3a. Interestingly, SIN3a overexpression inhibited hPASMC proliferation and upregulated BMPR2 expression by preventing the methylation of the BMPR2 promoter region. RNA sequencing analysis suggested that SIN3a downregulated the expression of DNA and histone methyltransferases such as DNMT1 and EZH2 while promoting the expression of the DNA demethylase TET1. Mechanistically, SIN3a promoted BMPR2 expression by decreasing CTCF binding to the BMPR2 promoter. Finally, we identified intratracheal delivery of AAV1.hSIN3a to be a beneficial therapeutic approach in PAH- by attenuating pulmonary vascular and RV remodeling, decreasing RVSP and mPAP pressure, and restoring BMPR2 expression in rodent models of PAH. Conclusions: Altogether, our study unveiled the protective/beneficial role of SIN3a in pulmonary hypertension. We also identified a novel and distinct molecular mechanism by which SIN3a regulates BMPR2 in hPASMC. Our study also identified lung-targeted SIN3a gene therapy using AAV1 as a new promising therapeutic strategy for treating patients with PAH.

Sign in / Sign up

Export Citation Format

Share Document