Endothelial cell senescence exacerbates pulmonary hypertension through Notch-mediated juxtacrine signaling

AbstractPulmonary arterial hypertension (PAH) is a fatal disease characterized by pathological pulmonary artery remodeling. Endothelial cells (EC) injury including DNA damage is critically involved in the vascular remodeling in PAH, and persistent injury leads to cellular senescence in ECs. Here, we show that EC senescence exacerbates pulmonary hypertension through Notch-mediated juxtacrine signaling. EC-specific progeroid mice that we recently generated showed exacerbated pulmonary hypertension after chronic hypoxia exposure, accompanied by the enhanced pulmonary arterial smooth muscle cells (PASMCs) proliferation in the distal pulmonary arteries. Mechanistically, we identified that senescent ECs highly expressed Notch ligands, and thus activated Notch signaling in PASMCs, leading to enhanced PASMCs proliferation and migration capacities. Consistently, pharmacological inhibition of Notch signaling attenuated the effects of senescent ECs on SMCs functions in vitro, and on the pulmonary hypertension in EC-specific progeroid mice in vivo. These data establish EC senescence as a crucial disease-modifying facor in PAH.

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Hydrogen Sulfide Metabolism and Pulmonary Hypertension

Cells ◽

10.3390/cells10061477 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1477

Author(s):

Lukas Roubenne ◽

Roger Marthan ◽

Bruno Le Le Grand ◽

Christelle Guibert

Keyword(s):

Pulmonary Hypertension ◽

Hydrogen Sulfide ◽

Pulmonary Circulation ◽

Pulmonary Arteries ◽

K Channel ◽

Protective Effects ◽

Pulmonary Arterial ◽

Regulatory Functions

Pulmonary hypertension (PH) is a severe and multifactorial disease characterized by a progressive elevation of pulmonary arterial resistance and pressure due to remodeling, inflammation, oxidative stress, and vasoreactive alterations of pulmonary arteries (PAs). Currently, the etiology of these pathological features is not clearly understood and, therefore, no curative treatment is available. Since the 1990s, hydrogen sulfide (H2S) has been described as the third gasotransmitter with plethoric regulatory functions in cardiovascular tissues, especially in pulmonary circulation. Alteration in H2S biogenesis has been associated with the hallmarks of PH. H2S is also involved in pulmonary vascular cell homeostasis via the regulation of hypoxia response and mitochondrial bioenergetics, which are critical phenomena affected during the development of PH. In addition, H2S modulates ATP-sensitive K+ channel (KATP) activity, and is associated with PA relaxation. In vitro or in vivo H2S supplementation exerts antioxidative and anti-inflammatory properties, and reduces PA remodeling. Altogether, current findings suggest that H2S promotes protective effects against PH, and could be a relevant target for a new therapeutic strategy, using attractive H2S-releasing molecules. Thus, the present review discusses the involvement and dysregulation of H2S metabolism in pulmonary circulation pathophysiology.

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Abstract 3570: A Critical and Novel Role of Nogo (Neurite Outgrowth Inhibitor) in Pulmonary Arterial Hypertension

Circulation ◽

10.1161/circ.118.suppl_18.s_446-a ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Gopinath Sutendra ◽

Sebastien Bonnet ◽

Paulette Wright ◽

Peter Dromparis ◽

Alois Haromy ◽

...

Keyword(s):

Pulmonary Arterial Hypertension ◽

Arterial Hypertension ◽

Nuclear Translocation ◽

Pulmonary Arteries ◽

Over Expression ◽

Nfat Activation ◽

Pulmonary Arterial ◽

Systemic Arteries

Nogo was first identified as an inhibitor of neuronal axonal regeneration. Recently, Nogo-B was implicated in the proliferative and anti-apoptotic remodeling in systemic arteries; reduced Nogo-B expression was seen in remodeled mouse femoral arteries following injury. Pulmonary arterial hypertension (PAH) is also characterized by proliferative/anti-apoptotic remodeling in pulmonary arteries (PA), sparing systemic vessels. PAH PA smooth muscle cells (PASMC) are characterized by mitochondrial hyperpolarization (increased ΔΨm), decreased production of reactive oxygen species (ROS) (suppressing mitochondria-dependent apoptosis), down-regulation of Kv1.5 and activation of the transcription factor NFAT (promoting contraction and proliferation). We found that in contrast to systemic vessels, Nogo-B expression is significantly increased in vivo and in vitro in PAs and PASMCs from patients (n=6) and mice (n=42) with PAH, compared to normals. We hypothesized that Nogo is involved in the pathogenesis of PAH . Nogo −/− mice (n=7) had a normal phenotype and, in contrast to Nogo +/+ , did not develop chronic hypoxia (CH)-induced PAH assessed invasively (catheterization, RV/LV+Septum) and non-invasively (pulmonary artery acceleration time and treadmill performance) (n=7, Table ). CH- Nogo +/+ PASMC had the expected increase in ΔΨm (measured by TMRM), decreased ROS (MitoSOX), increased [Ca ++ ] i (FLUO3), decreased Kv1.5 (immunohistochemistry) and NFAT activation (nuclear translocation). None of these changes occurred in CH- Nogo −/− PASMC while all were induced in normoxic Nogo +/+ PASMC by adenoviral over-expression of Nogo-B . Heterozygote CH- Nogo +/− (n=7) values were between Nogo −/− and Nogo +/+ suggesting a gene dose-dependent effect. Nogo is over-expressed in human and rodent PAH and induces critical features of the PAH phenotype. Nogo targeting might represent a novel and selective therapeutic strategy for PAH. Table

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Targeting IL-17 attenuates hypoxia-induced pulmonary hypertension through downregulation of β-catenin

Thorax ◽

10.1136/thoraxjnl-2018-211846 ◽

2019 ◽

Vol 74 (6) ◽

pp. 564-578 ◽

Cited By ~ 2

Author(s):

Lei Wang ◽

Jie Liu ◽

Wang Wang ◽

Xianmei Qi ◽

Ying Wang ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Lung Tissue ◽

Interleukin 17 ◽

Antibody Assays ◽

Coculture Model ◽

Potential Benefits ◽

Pulmonary Arterial ◽

And Migration ◽

Arterial Endothelial Cells

BackgroundThe role of interleukin 17 (IL-17) in hypoxic pulmonary hypertension (HPH) remains unclear. This study is designed to explore whether IL-17 is a potential target for HPH treatment.MethodsClinic samples from the lung tissue and serum were obtained from qualified patients. Western blotting, immunohistochemistry and/or ELISA were used to measure the expression of relevant proteins. HPH models were established in C57BL/6 wild-type (WT) and IL-17−/− mice and were treated with exogenous recombinant mouse IL-17 (rmIL-17) or an IL-17 neutralising antibody. Assays for cell proliferation, angiogenesis and adhesion were employed to analyse the behaviours of human pulmonary arterial endothelial cells (HPAECs). A non-contact Transwell coculture model was used to evaluate intercellular interactions.ResultsExpression of IL-17 was increased in lung tissue of both patients with bronchiectasis/COPD-associated PH and HPH mouse model. Compared with WT mice, IL-17−/− mice had attenuated HPH, whereas administration of rmIL-17 aggravated HPH. In vitro, recombinant human IL-17 (rhIL-17) promoted proliferation, angiogenesis and adhesion in HPAECs through upregulation of Wnt3a/β-catenin/CyclinD1 pathway, and siRNA-mediated knockdown of β-catenin almost completely reversed this IL-17-mediated phenomena. IL-17 promoted the proliferation but not the migration of human pulmonary arterial smooth muscle cells (HPASMCs) cocultured with HPAECs under both normoxia and hypoxia, but IL-17 had no direct effect on proliferation and migration of HPASMCs. Blockade of IL-17 with a neutralising antibody attenuated HPH in WT mice.ConclusionsIL-17 contributes to the pathogenesis of HPH through upregulation of β-catenin expression. Targeting IL-17 might provide potential benefits for alternative therapeutic strategies for HPH.

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NBS1 interacts with Notch signaling in neuronal homeostasis

Nucleic Acids Research ◽

10.1093/nar/gkaa716 ◽

2020 ◽

Vol 48 (19) ◽

pp. 10924-10939

Author(s):

Zhong-Wei Zhou ◽

Murat Kirtay ◽

Nadine Schneble ◽

George Yakoub ◽

Mingmei Ding ◽

...

Keyword(s):

Notch Signaling ◽

Notch Pathway ◽

Direct Consequence ◽

Nijmegen Breakage Syndrome ◽

Neuron Development ◽

Genetic Ablation ◽

Notch Activity ◽

And Migration

Abstract NBS1 is a critical component of the MRN (MRE11/RAD50/NBS1) complex, which regulates ATM- and ATR-mediated DNA damage response (DDR) pathways. Mutations in NBS1 cause the human genomic instability syndrome Nijmegen Breakage Syndrome (NBS), of which neuronal deficits, including microcephaly and intellectual disability, are classical hallmarks. Given its function in the DDR to ensure proper proliferation and prevent death of replicating cells, NBS1 is essential for life. Here we show that, unexpectedly, Nbs1 deletion is dispensable for postmitotic neurons, but compromises their arborization and migration due to dysregulated Notch signaling. We find that Nbs1 interacts with NICD-RBPJ, the effector of Notch signaling, and inhibits Notch activity. Genetic ablation or pharmaceutical inhibition of Notch signaling rescues the maturation and migration defects of Nbs1-deficient neurons in vitro and in vivo. Upregulation of Notch by Nbs1 deletion is independent of the key DDR downstream effector p53 and inactivation of each MRN component produces a different pattern of Notch activity and distinct neuronal defects. These data indicate that neuronal defects and aberrant Notch activity in Nbs1-deficient cells are unlikely to be a direct consequence of loss of MRN-mediated DDR function. This study discloses a novel function of NBS1 in crosstalk with the Notch pathway in neuron development.

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Mutual promotion of FGF21 and PPARγ attenuates hypoxia-induced pulmonary hypertension

Experimental Biology and Medicine ◽

10.1177/1535370219828692 ◽

2019 ◽

Vol 244 (3) ◽

pp. 252-261 ◽

Cited By ~ 3

Author(s):

Gexiang Cai ◽

Jingjing Liu ◽

Meibin Wang ◽

Lihuang Su ◽

Mengsi Cai ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Mouse Lung ◽

Fibroblast Growth Factor 21 ◽

Arterial Remodeling ◽

Collagen Deposition ◽

Pparγ Agonist ◽

Pulmonary Arterial ◽

The Relationship

Fibroblast growth factor 21 (FGF21), a primarily liver-derived endocrine factor, has the beneficial effect of protecting blood vessels. Peroxisome proliferator-activated receptor γ (PPARγ), a ligand-activated nuclear transcription factor, has been reported to effectively inhibit pulmonary hypertension (PH). The purpose of this study is to investigate the role of FGF21 in hypoxia-induced PH (HPH) and explore the relationship between FGF21 and PPARγ in this disorder. Adult C57BL/6 mice were subjected to four weeks of hypoxia to establish a PH model. The effects of FGF21 and PPARγ agonists and antagonists were investigated in HPH mice, as well as the relationship between FGF21 and PPARγ in this model. Moreover, we investigated the underlying mechanisms of this relationship between FGF21 and PPARγ in vivo and in vitro. In vivo, we found that hypoxia resulted in pulmonary hypertension, right ventricular hypertrophy, pulmonary arterial remodeling, and pulmonary arterial collagen deposition. Furthermore, hypoxia decreased FGF21 and PPARγ levels. These changes were reversed by exogenous FGF21 and a PPARγ agonist and were further enhanced by a PPARγ antagonist. The hypoxia-induced decrease in β-klotho (KLB) expression was improved by the PPARγ agonist and further reduced by the PPARγ antagonist. Exogenous FGF21 increased adenosine monophosphate-activated protein kinase (AMPK) phosphorylation (Thr172) and PPARγ coactivator-1α (PGC-1α) expression in PH mouse lung homogenates. In vitro, we found that knockdown of AMPK or using an AMPK antagonist inhibited the FGF21-mediated up-regulation of PPARγ expression, and the PPARγ-mediated up-regulation of FGF21 expression was inhibited by knockdown of KLB. These results indicated that FGF21 exerts protective effects in inhibiting HPH. FGF21 and PPARγ mutually promote each other’s expression in HPH via the AMPK/PGC-1α pathway and KLB protein. Impact statement In this study, we reported for the first time that FGF21 alleviated hypoxia-induced pulmonary hypertension through attenuation of increased pulmonary arterial pressure, pulmonary arterial remodeling and collagen deposition in vivo, and we confirmed the mutual promotion of FGF21 and PPARγ in hypoxia-induced pulmonary hypertension. Additionally, we found that FGF21 and PPARγ mutually promote each other’s expression via the AMPK/PGC-1α pathway and KLB protein in vitro and in vivo. Pulmonary hypertension is a progressive and serious pathological phenomenon with a poor prognosis, and current therapies are highly limited. Our results provide novel insight into potential clinical therapies for pulmonary hypertension and establish the possibility of using this drug combination and potential dosage reductions in clinical settings.

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The serotonin hypothesis in pulmonary hypertension revisited: targets for novel therapies (2017 Grover Conference Series)

Pulmonary Circulation ◽

10.1177/2045894018759125 ◽

2018 ◽

Vol 8 (2) ◽

pp. 204589401875912 ◽

Cited By ~ 30

Author(s):

Margaret (Mandy) R. MacLean

Keyword(s):

Pulmonary Hypertension ◽

Pulmonary Arteries ◽

Convincing Evidence ◽

Current Status ◽

Novel Therapies ◽

Serotonin Synthesis ◽

Pulmonary Arterial ◽

Arterial Smooth Muscle Cells ◽

Diet Pills ◽

Sert Activity

Increased synthesis of serotonin and/or activity of serotonin in pulmonary arteries has been implicated in the pathobiology of pulmonary arterial hypertension (PAH). The incidence of PAH associated with diet pills such as aminorex, fenfluramine, and chlorphentermine initially led to the “serotonin hypothesis of pulmonary hypertension.” Over the last couple of decades there has been an accumulation of convincing evidence that targeting serotonin synthesis or signaling is a novel and promising approach to the development of novel therapies for PAH. Pulmonary endothelial serotonin synthesis via tryptophan hydroxlase 1 (TPH1) is increased in patients with PAH and serotonin can act in a paracrine fashion on underlying pulmonary arterial smooth muscle cells (PASMCs), In humans, serotonin can enter PASMCs via the serotonin transporter (SERT) or activate the 5-HT1B receptor; 5-HT1B activation and SERT activity cooperate to induce PASMC contraction and proliferation via activation of downstream proliferative and contractile signaling pathways. Here we will review the current status of the serotonin hypothesis and discuss potential and novel therapeutic targets.

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MiRNA let-7b promotes the development of hypoxic pulmonary hypertension by targeting ACE2

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00387.2018 ◽

2019 ◽

Vol 316 (3) ◽

pp. L547-L557 ◽

Cited By ~ 14

Author(s):

Ruifeng Zhang ◽

Hua Su ◽

Xiuqing Ma ◽

Xiaoling Xu ◽

Li Liang ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Hypoxia Inducible Factor ◽

Underlying Mechanism ◽

Pulmonary Vessel ◽

Hypoxic Pulmonary Hypertension ◽

And Migration ◽

Ventricle Hypertrophy ◽

Proliferation And Migration

Angiotensin-converting enzyme 2 (ACE2) protects against hypoxic pulmonary hypertension (HPH) by inhibiting the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs). Under hypoxia, the hypoxia-inducible factor 1α (HIF-1α) inhibits ACE2 indirectly; however, the underlying mechanism is unclear. In the present study, we found that exposure to chronic hypoxia stimulated microRNA (miRNA) let-7b expression in rat lung via a HIF-1α-dependent pathway. Let-7b downregulated ACE2 expression by directly targeting the coding sequence of ACE2. Our in vitro and in vivo results revealed that let-7b contributed to the pathogenesis of HPH by inducing PASMCs proliferation and migration. Let-7b knockout mitigated right ventricle hypertrophy and pulmonary vessel remodeling in HPH by restoring ACE2 expression. Overall, we demonstrated that HIF-1α inhibited ACE2 expression via the HIF-1α-let-7b-ACE2 axis, which contributed to the pathogenesis of HPH by stimulating PASMCs proliferation and migration. Since let-7b knockout alleviated the development of HPH, let-7b may serve as a potential clinical target for the treatment of HPH.

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Hypoxia inhibits adenylyl cyclase catalytic activity in a porcine model of persistent pulmonary hypertension of the newborn

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00130.2018 ◽

2018 ◽

Vol 315 (6) ◽

pp. L933-L944 ◽

Cited By ~ 1

Author(s):

A. S. Sikarwar ◽

M. Hinton ◽

K. T. Santhosh ◽

P. Dhanaraj ◽

M. Talabis ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Catalytic Activity ◽

Adenylyl Cyclase ◽

Specific Activity ◽

Pulmonary Arteries ◽

Persistent Pulmonary Hypertension ◽

Receptor Agonists ◽

Pulmonary Arterial ◽

Fraction Of Inspired Oxygen

Persistent pulmonary hypertension of the newborn (PPHN) features hypoxemia, pulmonary vasoconstriction, and impaired cardiac inotropy. We previously reported low basal and stimulated cAMP in hypoxic pulmonary artery smooth muscle cells (PASMCs). We now examine pulmonary arterial adenylyl cyclase (AC) activity and regulation in hypoxic PPHN. PPHN was induced in newborn swine by normobaric hypoxia (fraction of inspired oxygen 0.10) for 72 h and compared with age-matched normoxic controls. We studied relaxation of pulmonary arterial (PA) rings to AC activator forskolin and cGMP activator sodium nitroprusside (SNP) by isometric myography, ATP content, phosphodiesterase activity, AC content, isoform expression, and catalytic activity in presence or absence of Gαs-coupled receptor agonists, forskolin, or transnitrosylating agents in human and neonatal porcine PASMCs and HEK293T stably expressing AC isoform 6, after 72 h hypoxia (10% O2) or normoxia (21% O2). Relaxation to forskolin and SNP were equally impaired in PPHN PA. AC-specific activity decreased in hypoxia. PASMC from PPHN swine had reduced AC activity despite exposure to normoxia in culture; transient hypoxia in vitro further decreased AC activity. Prostacyclin receptor ligand affinity decreased, but its association with Gαs increased in hypoxia. Total AC content was unchanged by hypoxia, but AC6 increased in hypoxic cells and PPHN pulmonary arteries. Impairment of AC6 activity in hypoxia was associated with nitrosylation. PPHN PA relaxation is impaired because of loss of AC activity. Hypoxic AC is inhibited because of S-nitrosylation; inhibition persists after removal from hypoxia. Downregulation of AC-mediated relaxation in hypoxic PA has implications for utility of Gαs-coupled receptor agonists in PPHN treatment.

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Exposure of mice to chronic hypoxia attenuates pulmonary arterial contractile responses to acute hypoxia by increases in extracellular hydrogen peroxide

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00257.2013 ◽

2014 ◽

Vol 307 (4) ◽

pp. R426-R433 ◽

Cited By ~ 14

Author(s):

Dhara Patel ◽

Raed Alhawaj ◽

Michael S. Wolin

Keyword(s):

Hydrogen Peroxide ◽

Pulmonary Hypertension ◽

Chronic Hypoxia ◽

Soluble Guanylate Cyclase ◽

Aminolevulinic Acid ◽

Acute Hypoxia ◽

Pulmonary Arteries ◽

Protoporphyrin Ix

Exposing mice to a chronic hypoxic treatment (10% oxygen, 21 days) that promotes pulmonary hypertension was observed to attenuate the pulmonary vasoconstriction response to acute hypoxia (HPV) both in vivo and in isolated pulmonary arteries. Since catalase restored the HPV response in isolated arteries, it appeared to be attenuated by extracellular hydrogen peroxide. Chronic hypoxia promoted the detection of elevated lung superoxide, extracellular peroxide, extracellular SOD expression, and protein kinase G (PKG) activation [based on PKG dimerization and vasodilator-stimulated phosphoprotein (VASP) phosphorylation], suggesting increased generation of extracellular peroxide and PKG activation may contribute to the suppression of HPV. Aorta from mice exposed to 21 days of hypoxia also showed evidence for extracellular hydrogen peroxide, suppressing the relaxation response to acute hypoxia. Peroxide appeared to partially suppress contractions to phenylephrine used in the study of in vitro hypoxic responses. Treatment of mice with the heme precursor δ-aminolevulinic acid (ALA; 50 mg·kg−1·day−1) during exposure to chronic hypoxia was examined as a pulmonary hypertension therapy because it could potentially activate beneficial cGMP-mediated effects through promoting a prolonged protoporphyrin IX (PpIX)-elicited activation of soluble guanylate cyclase. ALA attenuated pulmonary hypertension, increases in both superoxide and peroxide, and the suppression of in vitro and in vivo HPV responses. ALA generated prolonged detectible increases in PpIX and PKG-associated phosphorylation of VASP, suggesting PKG activation may contribute to suppression of pulmonary hypertension and prevention of alterations in extracellular peroxide that appear to be attenuating HPV responses caused by chronic hypoxia.

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IL-13 receptor α2-arginase 2 pathway mediates IL-13-induced pulmonary hypertension

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00101.2012 ◽

2013 ◽

Vol 304 (2) ◽

pp. L112-L124 ◽

Cited By ~ 26

Author(s):

Won-Kyung Cho ◽

Chang-Min Lee ◽

Min-Jong Kang ◽

Yan Huang ◽

Frank J. Giordano ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Cellular Proliferation ◽

Pulmonary Arteries ◽

Systolic Pressure ◽

Direct Proof ◽

Dependent Manner ◽

Sirna Silencing ◽

Null Mutant Mice

Although previous literature suggests that interleukin (IL)-13, a T-helper type 2 cell effector cytokine, might be involved in the pathogenesis of pulmonary hypertension (PH), direct proof is lacking. Furthermore, a potential mechanism underlying IL-13-induced PH has never been explored. This study's goal was to investigate the role and mechanism of IL-13 in the pathogenesis of PH. Lung-specific IL-13-overexpressing transgenic (Tg) mice were examined for hemodynamic changes and pulmonary vascular remodeling. IL-13 Tg mice spontaneously developed PH phenotype by the age of 2 mo with increased expression and activity of arginase 2 (Arg2). The role of Arg2 in the development of IL-13-stimulated PH was further investigated using Arg2 and IL-13 receptor α2 (Rα2) null mutant mice and the small-interfering RNA (siRNA)-silencing approach in vivo and in vitro, respectively. IL-13-stimulated medial thickening of pulmonary arteries and right ventricle systolic pressure were significantly decreased in the IL-13 Tg mice with Arg2 null mutation. On the other hand, the production of nitric oxide was further increased in the lungs of these mice. In our in vitro evaluations, the recombinant IL-13 treatment significantly enhanced the proliferation of human pulmonary artery smooth muscle cells in an Arg2-dependent manner. The IL-13-stimulated cellular proliferation and the expression of Arg2 in hpaSMC were markedly decreased with IL-13Rα2 siRNA silencing. Our studies demonstrate that IL-13 contributes to the development of PH via an IL-13Rα2-Arg2-dependent pathway. The intervention of this pathway could be a potential therapeutic target in pulmonary arterial hypertension.

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