Endothelial Cells in the Pathogenesis of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease that involves pulmonary vasoconstriction, small vessel obliteration, large vessel thickening and obstruction, and development of plexiform lesions. PAH vasculopathy leads to progressive increases in pulmonary vascular resistance, right heart failure, and ultimately, premature death. Besides other cell types that are known to be involved in PAH pathogenesis (e.g. smooth muscle cells, fibroblasts, and leukocytes), recent studies demonstrate a crucial role of endothelial cells (ECs) in the initiation and progression of PAH. The EC-specific role in PAH is multi-faceted and impacts upon numerous pathophysiological processes including vasoconstriction, inflammation, coagulation, metabolism, and oxidative/nitrative stress, as well as cell viability, growth, and differentiation. In this review, we describe how EC dysfunction and cell signalling regulate the pathogenesis of PAH. We also highlight areas of research that warrant attention in future studies, and discuss potential molecular signalling pathways in ECs that could be targeted therapeutically in the prevention and treatment of PAH.

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Traditional Herbal Medicine Discovery for the Treatment and Prevention of Pulmonary Arterial Hypertension

Frontiers in Pharmacology ◽

10.3389/fphar.2021.720873 ◽

2021 ◽

Vol 12 ◽

Author(s):

Zhifeng Xue ◽

Yixuan Li ◽

Mengen Zhou ◽

Zhidong Liu ◽

Guanwei Fan ◽

...

Keyword(s):

Pulmonary Arterial Hypertension ◽

Herbal Medicine ◽

Pulmonary Artery ◽

Arterial Hypertension ◽

Premature Death ◽

Right Heart Failure ◽

Tanshinone Iia ◽

Active Components ◽

Traditional Herbal Medicine ◽

Pulmonary Arterial

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.

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

Circulation ◽

10.1161/circ.142.suppl_3.14880 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

BIN LIU ◽

Jingbo Dai ◽

Li Shuai ◽

Dan Yi ◽

Youyang Zhao ◽

...

Keyword(s):

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Single Cell ◽

Vascular Remodeling ◽

Molecular Mechanisms ◽

Premature Death ◽

Right Heart Failure ◽

Fatty Acid Binding ◽

Pulmonary Arterial ◽

Endothelial Plasticity

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.

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Targeting HIF2α-ARNT hetero-dimerisation as a novel therapeutic strategy for Pulmonary Arterial Hypertension

European Respiratory Journal ◽

10.1183/13993003.02061-2019 ◽

2020 ◽

pp. 1902061

Author(s):

David Macias ◽

Stephen Moore ◽

Alexi Crosby ◽

Mark Southwood ◽

Xinlin Du ◽

...

Keyword(s):

Endothelial Cells ◽

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Target Genes ◽

Right Heart Failure ◽

Pulmonary Vasculature ◽

Pulmonary Arterial ◽

The Impact

Pulmonary Arterial Hypertension (PAH) is a destructive disease of the pulmonary vasculature often leading to right heart failure and death. Current therapeutic intervention strategies only slow disease progression. The role of aberrant HIF2α stability and function in the initiation and development of pulmonary hypertension (PH) has been an area of intense interest for nearly two decades.Here we determine the effect of a novel HIF2α inhibitor (PT2567) on PH disease initiation and progression, using two pre-clinical models of PH. Haemodynamic measurements were performed followed by collection of heart, lung and blood for pathological, gene expression and biochemical analysis. Blood outgrowth endothelial cells from IPAH patients were used to determine the impact of HIF2α-inhibition on endothelial function.Global inhibition of HIF2a reduced pulmonary vascular haemodynamics and pulmonary vascular remodelling in both su5416/hypoxia prevention and intervention models. PT2567 intervention reduced the expression of PH associated target genes in both lung and cardiac tissues and restored plasma nitrite concentration. Treatment of monocrotaline exposed rodents with PT2567 reduced the impact on cardiovascular haemodynamics and promoted a survival advantage. In vitro, loss of HIF2α signalling in human pulmonary arterial endothelial cells suppresses target genes associated with inflammation, and PT2567 reduced the hyper-proliferative phenotype and over-active arginase activity in blood outgrowth endothelial cells from IPAH patients. These data suggest that targeting HIF2α hetero-dimerisation with an orally bioavailable compound could offer a new therapeutic approach for PAH. Future studies are required to determine the role of HIF in the heterogeneous PAH population.

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Epigenetic Mechanisms as Emerging Therapeutic Targets and Microfluidic Chips Application in Pulmonary Arterial Hypertension

Biomedicines ◽

10.3390/biomedicines10010170 ◽

2022 ◽

Vol 10 (1) ◽

pp. 170

Author(s):

Linh Ho ◽

Nazir Hossen ◽

Trieu Nguyen ◽

Au Vo ◽

Fakhrul Ahsan

Keyword(s):

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Vascular Remodeling ◽

Right Heart Failure ◽

Cell Types ◽

Epigenetic Mechanisms ◽

Microfluidic Chips ◽

Transcriptional Responses ◽

Pulmonary Arterial ◽

Epigenetic Regulators

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.

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Transcriptional profiling of lung cell populations in idiopathic pulmonary arterial hypertension

Pulmonary Circulation ◽

10.1177/2045894020908782 ◽

2020 ◽

Vol 10 (1) ◽

pp. ??? ◽

Cited By ~ 2

Author(s):

Didem Saygin ◽

Tracy Tabib ◽

Humberto E.T. Bittar ◽

Eleanor Valenzi ◽

John Sembrat ◽

...

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Smooth Muscle Cells ◽

Muscle Cells ◽

Cell Types ◽

Idiopathic Pulmonary Arterial Hypertension ◽

Differential Gene ◽

Pulmonary Arterial

Despite recent improvements in management of idiopathic pulmonary arterial hypertension, mortality remains high. Understanding the alterations in the transcriptome–phenotype of the key lung cells involved could provide insight into the drivers of pathogenesis. In this study, we examined differential gene expression of cell types implicated in idiopathic pulmonary arterial hypertension from lung explants of patients with idiopathic pulmonary arterial hypertension compared to control lungs. After tissue digestion, we analyzed all cells from three idiopathic pulmonary arterial hypertension and six control lungs using droplet-based single cell RNA-sequencing. After dimensional reduction by t-stochastic neighbor embedding, we compared the transcriptomes of endothelial cells, pericyte/smooth muscle cells, fibroblasts, and macrophage clusters, examining differential gene expression and pathways implicated by analysis of Gene Ontology Enrichment. We found that endothelial cells and pericyte/smooth muscle cells had the most differentially expressed gene profile compared to other cell types. Top differentially upregulated genes in endothelial cells included novel genes: ROBO4, APCDD1, NDST1, MMRN2, NOTCH4, and DOCK6, as well as previously reported genes: ENG, ORAI2, TFDP1, KDR, AMOTL2, PDGFB, FGFR1, EDN1, and NOTCH1. Several transcription factors were also found to be upregulated in idiopathic pulmonary arterial hypertension endothelial cells including SOX18, STRA13, LYL1, and ELK, which have known roles in regulating endothelial cell phenotype. In particular, SOX18 was implicated through bioinformatics analyses in regulating the idiopathic pulmonary arterial hypertension endothelial cell transcriptome. Furthermore, idiopathic pulmonary arterial hypertension endothelial cells upregulated expression of FAM60A and HDAC7, potentially affecting epigenetic changes in idiopathic pulmonary arterial hypertension endothelial cells. Pericyte/smooth muscle cells expressed genes implicated in regulation of cellular apoptosis and extracellular matrix organization, and several ligands for genes showing increased expression in endothelial cells. In conclusion, our study represents the first detailed look at the transcriptomic landscape across idiopathic pulmonary arterial hypertension lung cells and provides robust insight into alterations that occur in vivo in idiopathic pulmonary arterial hypertension lungs.

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Extracellular matrix degradation pathways and fatty acid metabolism regulate distinct pulmonary vascular cell types in pulmonary arterial hypertension

Pulmonary Circulation ◽

10.1177/2045894021996190 ◽

2021 ◽

Vol 11 (1) ◽

pp. 204589402199619

Author(s):

Sharon Mumby ◽

F. Perros ◽

C. Hui ◽

B.L. Xu ◽

W. Xu ◽

...

Keyword(s):

Endothelial Cells ◽

Smooth Muscle ◽

Pulmonary Arterial Hypertension ◽

Pulmonary Artery ◽

Arterial Hypertension ◽

Cell Types ◽

Microvascular Endothelial Cells ◽

Pulmonary Arterial ◽

Pulmonary Artery Smooth Muscle ◽

Human Pulmonary Artery

Pulmonary arterial hypertension describes a group of diseases characterised by raised pulmonary vascular resistance, resulting from vascular remodelling in the pre-capillary resistance arterioles. Left untreated, patients die from right heart failure. Pulmonary vascular remodelling involves all cell types but to date the precise roles of the different cells is unknown. This study investigated differences in basal gene expression between pulmonary arterial hypertension and controls using both human pulmonary microvascular endothelial cells and human pulmonary artery smooth muscle cells. Human pulmonary microvascular endothelial cells and human pulmonary artery smooth muscle cells from pulmonary arterial hypertension patients and controls were cultured to confluence, harvested and RNA extracted. Whole genome sequencing was performed and after transcript quantification and normalisation, we examined differentially expressed genes and applied gene set enrichment analysis to the differentially expressed genes to identify putative activated pathways. Human pulmonary microvascular endothelial cells displayed 1008 significant ( p ≤ 0.0001) differentially expressed genes in pulmonary arterial hypertension samples compared to controls. In human pulmonary artery smooth muscle cells, there were 229 significant ( p ≤ 0.0001) differentially expressed genes between pulmonary arterial hypertension and controls. Pathway analysis revealed distinctive differences: human pulmonary microvascular endothelial cells display down-regulation of extracellular matrix organisation, collagen formation and biosynthesis, focal- and cell-adhesion molecules suggesting severe endothelial barrier dysfunction and vascular permeability in pulmonary arterial hypertension pathogenesis. In contrast, pathways in human pulmonary artery smooth muscle cells were mainly up-regulated, including those for fatty acid metabolism, biosynthesis of unsaturated fatty acids, cell–cell and adherens junction interactions suggesting a more energy-driven proliferative phenotype. This suggests that the two cell types play different mechanistic roles in pulmonary arterial hypertension pathogenesis and further studies are required to fully elucidate the role each plays and the interactions between these cell types in vascular remodelling in disease progression.

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Novel strategies for treatment of pulmonary arterial hypertension

Postępy Higieny i Medycyny Doświadczalnej ◽

10.5604/01.3001.0010.3838 ◽

2017 ◽

Vol 71 (1) ◽

pp. 0-0

Author(s):

Magdalena Jasińska-Stroschein ◽

Daria Orszulak-Michalak

Keyword(s):

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Signaling Pathways ◽

Molecular Mechanisms ◽

Combined Therapy ◽

Treatment Options ◽

Premature Death ◽

Right Heart Failure ◽

Phosphodiesterase Type 5 Inhibitors ◽

Pulmonary Arterial

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.

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