Abstract 14880: Single-cell Transcriptomes Identify Unique Endothelial Subpopulation (FABP4 + TMEM100 - ) With Lipid Metabolism Dysfunction in Pulmonary Arterial Hypertension

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
BIN LIU ◽  
Jingbo Dai ◽  
Li Shuai ◽  
Dan Yi ◽  
Youyang Zhao ◽  
...  

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: We hypothesis that endothelial plasticity or distinct cell populations are critical for obstructive vascular remodeling in the pathogenesis of PAH. Methods: Here we applied single-cell RNA sequencing (ScRNA-seq) to profile the pulmonary cells in a severe mouse model ( Egln1 Tie2Cre mice) of PAH. Human hPAEC from idiopathic PAH patients and healthy donors were used to measure FABP4 and FABP5 expression. siRNA mediated knockdown of FABP4 and FABP5 was performed to study cell proliferation and apoptosis. Mice with Fabp4 and Fabp5 deletion ( Fabp45 -/- ) and wild type (WT) mice were incubated with hypoxia (10% O 2 ) to induced PAH. Egln1 Tie2Cre mice were bred with Fabp45 -/- mice to generate Egln1 Tie2Cre / Fabp45 -/- mice. Results: We identified five distinct EC subpopulations in both WT and Egln1 Tie2Cre mice via scRNA-seq. Unexpectedly, the number of Cluster (EC2, 49.8%) was markedly increased in Egln1 Tie2Cre lung compared with WT lung (2.8%). EC2 cluster (mainly from Egln1 Tie2Cre lung) was characterized by little expression of Tmem100 , Cldn5 , Tspan7 , Calcrl and Foxf1 and high expression of Fabp4, Cdh13, Sparl1 and Fabp5 . Fatty acid-binding protein (FABP) 4 and FABP5 (FABP4-5) were highly induced in PAECs from IPAH patients. Knockdown of FABP4-5 reduced EC proliferation and starvation-induced Caspase 3/7 activity. Fabp45 -/- mice were protected from hypoxia-induced PAH compared to WT mice. Moreover, Egln1 Tie2Cre / Fabp45 -/- mice also exhibited a reduction of RVSP and RV hypertrophy compared to Egln1 Tie2Cre mice. Conclusions: ScRNA-seq analysis identifies a unique endothelial population (FABP4 + TMEM100 - ) highly enriched in the lung of severe PAH mice. Knockdown of FABP4-5 reduces EC proliferation starvation-induced injury. Genetic deletion of FABP4-5 protects from hypoxia and Egln1 deficiency-induced PAH in mice.

2017 ◽  
Vol 131 (15) ◽  
pp. 2019-2035 ◽  
Author(s):  
Imad Al Ghouleh ◽  
Sanghamitra Sahoo ◽  
Daniel N. Meijles ◽  
Jefferson H. Amaral ◽  
Daniel S. de Jesus ◽  
...  

Pulmonary arterial hypertension (PAH) is a rapidly degenerating and devastating disease of increased pulmonary vessel resistance leading to right heart failure. Palliative modalities remain limited despite recent endeavors to investigate the mechanisms underlying increased pulmonary vascular resistance (PVR), i.e. aberrant vascular remodeling and occlusion. However, little is known of the molecular mechanisms responsible for endothelial proliferation, a root cause of PAH-associated vascular remodeling. Lung tissue specimens from PAH and non-PAH patients and hypoxia-exposed human pulmonary artery endothelial cells (ECs) (HPAEC) were assessed for mRNA and protein expression. Reactive oxygen species (ROS) were measured using cytochrome c and Amplex Red assays. Findings demonstrate for the first time an up-regulation of NADPH oxidase 1 (Nox1) at the transcript and protein level in resistance vessels from PAH compared with non-PAH patients. This coincided with an increase in ROS production and expression of bone morphogenetic protein (BMP) antagonist Gremlin1 (Grem1). In HPAEC, hypoxia induced Nox1 subunit expression, assembly, and oxidase activity leading to elevation in sonic hedgehog (SHH) and Grem1 expression. Nox1 gene silencing abrogated this cascade. Moreover, loss of either Nox1, SHH or Grem1 attenuated hypoxia-induced EC proliferation. Together, these data support a Nox1-SHH-Grem1 signaling axis in pulmonary vascular endothelium that is likely to contribute to pathophysiological endothelial proliferation and the progression of PAH. These findings also support targeting of Nox1 as a viable therapeutic option to combat PAH.


2017 ◽  
Vol 71 (1) ◽  
pp. 0-0
Author(s):  
Magdalena Jasińska-Stroschein ◽  
Daria Orszulak-Michalak

Pulmonary hypertension (PH) is a rare disorder associated with abnormally elevated pulmonary pressures that, if untreated, leads to right heart failure and premature death. Special population include patents with pulmonary arterial hypertension (PAH). A greater understanding of the epidemiology, pathogenesis, and pathophysiology of PAH has led to significant advances over the past few years. Modern drug therapy provides a significant improvement in patient symptomatic status and a slower rate of clinical deterioration. Despite this, PAH remains a chronic disease without a cure. There is a need for the development of novel therapies and therapeutic strategies, as treatment options are neither universally available nor always effective, possibly due to the large number of mediator and signaling pathways with downstream effectors which are implicated in the pathobiology of PH, and which are not fully reversed during PAH therapy. In the following pages, we review novel strategies for treatment of PAH. For this purpose we summarized the role of specific drug therapies that involve: endothelin receptor antagonists (ERA), phosphodiesterase type 5 inhibitors (PDE-5i) and prostacyclin and prostanoids (PGI2). We focused on novel molecular mechanisms in PAH of recently approved: Guanylate cyclase stimulator and non-prostanoid IP receptor agonist. We discussed novel approach to combined therapy, as well as a new generation of investigational drugs and promising PAH-associated signaling pathways, such as, PDGF, RhoA/ROCK RAAS, HT-5 and others.


2021 ◽  
Vol 12 ◽  
Author(s):  
Zhifeng Xue ◽  
Yixuan Li ◽  
Mengen Zhou ◽  
Zhidong Liu ◽  
Guanwei Fan ◽  
...  

Pulmonary arterial hypertension (PAH) is characterized by pulmonary artery remodeling that may subsequently culminate in right heart failure and premature death. Although there are currently both non-pharmacological (lung transplantation, etc.) and pharmacological (Sildenafil, Bosentan, and new oral drugs on trial) therapies available, PAH remains a serious and fatal pulmonary disease. As a unique medical treatment, traditional herbal medicine (THM) treatment has gradually exerted its advantages in treating PAH worldwide through a multi-level and multi-target approach. Additionally, the potential mechanisms of THM were deciphered, including suppression of proliferation and apoptosis of pulmonary artery smooth muscle cells, controlling the processes of inflammation and oxidative stress, and regulating vasoconstriction and ion channels. In this review, the effects and mechanisms of the frequently studied compound THM, single herbal preparations, and multiple active components from THM are comprehensively summarized, as well as their related mechanisms on several classical preclinical PAH models. It is worth mentioning that sodium tanshinone IIA sulfonate sodium and tetramethylpyrazine are under clinical trials and are considered the most promoting medicines for PAH treatment. Last, reverse pharmacology, a strategy to discover THM or THM-derived components, has also been proposed here for PAH. This review discusses the current state of THM, their working mechanisms against PAH, and prospects of reverse pharmacology, which are expected to facilitate the natural anti-PAH medicine discovery and development and its bench-to-bedside transformation.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Zhiyu Dai ◽  
Dan Yi ◽  
BIN LIU ◽  
Shuai Li

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.


2017 ◽  
Vol 8 (1) ◽  
pp. 204589321775291 ◽  
Author(s):  
Benoît Ranchoux ◽  
Lloyd D. Harvey ◽  
Ramon J. Ayon ◽  
Aleksandra Babicheva ◽  
Sebastien Bonnet ◽  
...  

Endothelial dysfunction is a major player in the development and progression of vascular pathology in pulmonary arterial hypertension (PAH), a disease associated with small vessel loss and obstructive vasculopathy that leads to increased pulmonary vascular resistance, subsequent right heart failure, and premature death. Over the past ten years, there has been tremendous progress in our understanding of pulmonary endothelial biology as it pertains to the genetic and molecular mechanisms that orchestrate the endothelial response to direct or indirect injury, and how their dysregulation can contribute to the pathogenesis of PAH. As one of the major topics included in the 2017 Grover Conference Series, discussion centered on recent developments in four areas of pulmonary endothelial biology: (1) angiogenesis; (2) endothelial-mesenchymal transition (EndMT); (3) epigenetics; and (4) biology of voltage-gated ion channels. The present review will summarize the content of these discussions and provide a perspective on the most promising aspects of endothelial dysfunction that may be amenable for therapeutic development.


Biomedicines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 170
Author(s):  
Linh Ho ◽  
Nazir Hossen ◽  
Trieu Nguyen ◽  
Au Vo ◽  
Fakhrul Ahsan

Pulmonary arterial hypertension (PAH) is a disease that progress over time and is defined as an increase in pulmonary arterial pressure and pulmonary vascular resistance that frequently leads to right-ventricular (RV) failure and death. Epigenetic modifications comprising DNA methylation, histone remodeling, and noncoding RNAs (ncRNAs) have been established to govern chromatin structure and transcriptional responses in various cell types during disease development. However, dysregulation of these epigenetic mechanisms has not yet been explored in detail in the pathology of pulmonary arterial hypertension and its progression with vascular remodeling and right-heart failure (RHF). Targeting epigenetic regulators including histone methylation, acetylation, or miRNAs offers many possible candidates for drug discovery and will no doubt be a tempting area to explore for PAH therapies. This review focuses on studies in epigenetic mechanisms including the writers, the readers, and the erasers of epigenetic marks and targeting epigenetic regulators or modifiers for treatment of PAH and its complications described as RHF. Data analyses from experimental cell models and animal induced PAH models have demonstrated that significant changes in the expression levels of multiple epigenetics modifiers such as HDMs, HDACs, sirtuins (Sirt1 and Sirt3), and BRD4 correlate strongly with proliferation, apoptosis, inflammation, and fibrosis linked to the pathological vascular remodeling during PAH development. The reversible characteristics of protein methylation and acetylation can be applied for exploring small-molecule modulators such as valproic acid (HDAC inhibitor) or resveratrol (Sirt1 activator) in different preclinical models for treatment of diseases including PAH and RHF. This review also presents to the readers the application of microfluidic devices to study sex differences in PAH pathophysiology, as well as for epigenetic analysis.


2012 ◽  
Vol 302 (8) ◽  
pp. H1546-H1562 ◽  
Author(s):  
Frank K. Kuhr ◽  
Kimberly A. Smith ◽  
Michael Y. Song ◽  
Irena Levitan ◽  
Jason X-J. Yuan

Pulmonary arterial hypertension (PAH) is a severe and progressive disease that usually culminates in right heart failure and death if left untreated. Although there have been substantial improvements in our understanding and significant advances in the management of this disease, there is a grim prognosis for patients in the advanced stages of PAH. A major cause of PAH is increased pulmonary vascular resistance, which results from sustained vasoconstriction, excessive pulmonary vascular remodeling, in situ thrombosis, and increased pulmonary vascular stiffness. In addition to other signal transduction pathways, Ca2+ signaling in pulmonary artery smooth muscle cells (PASMCs) plays a central role in the development and progression of PAH because of its involvement in both vasoconstriction, through its pivotal effect of PASMC contraction, and vascular remodeling, through its stimulatory effect on PASMC proliferation. Altered expression, function, and regulation of ion channels and transporters in PASMCs contribute to an increased cytosolic Ca2+ concentration and enhanced Ca2+ signaling in patients with PAH. This review will focus on the potential pathogenic role of Ca2+ mobilization, regulation, and signaling in the development and progression of PAH.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yann Grobs ◽  
Charlotte romanet ◽  
Valerie Nadeau ◽  
Junichi Omura ◽  
Mark Orcholski ◽  
...  

Like cancer, pulmonary arterial hypertension (PAH) is characterized by exaggerated proliferation and resistance to apoptosis related to metabolic alterations (Warburg effect) of pulmonary smooth muscle cells (PASMCs). These anomalies result in a progressive narrowing of the pulmonary arteries, increasing pulmonary resistance and leading to right heart failure and premature death. In cancer cells, unphosphorylated and nuclear FOXO3 has been extensively studied as a crucial protein that functions as a tumor suppressor by regulating expression of genes involved in apoptosis and cell cycle arrest. These functions combined with other FOXO3 attributes, including its key role in communicating mitochondrial-nuclear signals, make the FOXO3 a suitable candidate for controlling the cancer-like phenotype of PAH-PASMCs. Interestingly, AKT and AMPK known to be implicated in PAH exert antagonistic effects on FOXO3; AKT promoting its nuclear exclusion while AMPK favors its nuclear and mitochondrial accumulation. The thus made the hypothesis that FOXO3’s nuclear exclusion (secondary to AKT/AMPK imbalance) promotes metabolic reprogramming towards glycolysis leading to enhanced proliferation/resistance to apoptosis of PAH-PASMCs and vascular remodeling. Using Western blot and immunofluorescence in isolated PASMCs from both PAH and control patients (n=10), we found that nuclear and mitochondrial exclusion of FOXO3 due to its phosphorylation is a feature of PAH-PASMCs. In vitro, we demonstrated that nuclear localization of FOXO3 using an adenovirus expressing a constitutively active, non-phosphorylable form of FOXO3 or trifluoperazine (TFP) resulted in reduced PAH-PASMC proliferation (Ki67 labeling, p<0,0005) and resistance to apoptosis (Annexin V assay, p<0,05). These effects were accompanied by increased expression of P27 and SOD2 and diminished expression of Survivin (p<0,05). In vivo, we showed that FOXO3 activation using TPF improved established PAH in the monocrotaline rats (reduced RVSP and increased Sv and CO, by right catheterization, p<0,01, n=29) without any sign of toxicity. We showed that FOXO3 is implicated in pulmonary vascular remodeling. Pharmacological activation of FOXO3 may represent a novel avenue to improve PAH.


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