Progression Of Pulmonary Arterial Hypertension Research Articles

Saluisn-β contributes to endothelial dysfunction in monocrotaline-induced pulmonary arterial hypertensive rats

BackgroundThe endothelial dysfunction and the consequent attenuated pulmonary vasodilatation are the major causes of elevated pulmonary arterial resistance and pressure in pulmonary arterial hypertension (PAH). Current study aimed to explore the effects of a TOR2A gene product, salusin-β, on endothelium-dependent vascular relaxation and the progression of PAH in monocrotaline (MCT)-induced PAH rats as well as the relevant signaling pathway. MethodsAcetylcholine (ACh)-induced dose-dependent relaxation was used to evaluate the endothelium-dependent vasodilatation function. ResultsThe salusin-β level in plasma and pulmonary artery (PA) in MCT-PAH rats were significantly increased, while the ACh-induced endothelium-dependent vasodilatation was attenuated. After salusin-β incubation or overexpression of salusin-β gene, the endothelium-dependent relaxation was further deteriorated, while anti-salusin-β IgG incubation or knockdown of salusin-β improved it in PAH rats. The superoxide anions scavenger NAC or the antioxidant apocynin inhibited the effect of salusin-β, while the SOD inhibitor DETC further enhanced it. The nitric oxide (NO) synthase inhibitor L-NAME almost blocked the effect of anti-salusin-β IgG. Silencing of salusin-β in PAH rats decreased right ventricular (RV) systolic pressure, RV hypertrophy index, NAD(P)H oxidase activity and ROS level, and increased the eNOS activity and NO level of PA. Overexpression of salusin-β played opposite roles. ConclusionsThe elevated saluisn-β level in PAH rats plays important roles in the reduction of endothelium-dependent vasodilatation and participates in the progression of PAH through stimulating NAD(P)H oxidase-ROS production and inhibiting eNOS-NO release.

FAM171B as a Novel Biomarker Mediates Tissue Immune Microenvironment in Pulmonary Arterial Hypertension.

The purpose of this study was to uncover potential diagnostic indicators of pulmonary arterial hypertension (PAH), evaluate the function of immune cells in the pathogenesis of the disease, and find innovative treatment targets and medicines with the potential to enhance prognosis. Gene Expression Omnibus was utilized to acquire the PAH datasets. We recognized differentially expressed genes (DEGs) and investigated their functions utilizing R software. Weighted gene coexpression network analysis, least absolute shrinkage and selection operators, and support vector machines were used to identify biomarkers. The extent of immune cell infiltration in the normal and PAH tissues was determined using CIBERSORT. Additionally, the association between diagnostic markers and immune cells was analyzed. In this study, 258DEGs were used to analyze the disease ontology. Most DEGs were linked with atherosclerosis, arteriosclerotic cardiovascular disease, and lung disease, including obstructive lung disease. Gene set enrichment analysis revealed that compared to normal samples, results from PAH patients were mostly associated with ECM-receptor interaction, arrhythmogenic right ventricular cardiomyopathy, the Wnt signaling pathway, and focal adhesion. FAM171B was identified as a biomarker for PAH (area under the curve = 0.873). The mechanism underlying PAH may be mediated by nave CD4 T cells, resting memory CD4 T cells, resting NK cells, monocytes, activated dendritic cells, resting mast cells, and neutrophils, according to an investigation of immune cell infiltration. FAM171B expression was also associated with resting mast cells, monocytes, and CD8 T cells. The results suggest that PAH may be closely related to FAM171B with high diagnostic performance and associated with immune cell infiltration, suggesting that FAM171B may promote the progression of PAH by stimulating immune infiltration and immune response. This study provides valuable insights into the pathogenesis and treatment of PAH.

Abstract P1075: Elucidate The Mechanism Driving The Imbalance Between BMPs And Activin/Gdfs Signaling In Pulmonary Arterial Hypertension

Transforming Growth Factor-beta (TGF-β) family signaling is involved in Pulmonary Arterial Hypertension (PAH) in humans. PAH is a rare, highly morbid disorder characterized by dysregulated pulmonary vascular remodeling, elevated pulmonary vascular resistance, and the progressive obliteration of the pulmonary arteriolar circulation. The progression of PAH is largely influenced by the proliferation and migration of the pulmonary smooth muscle cells (PASMCs) and pulmonary endothelial cells (PAECs). While the exact mechanism is not understood, there is evidence that germline mutations in the BMPRII gene, one of the TGF-β family type II receptors, is present in PAH patients. Due to the functional similarity of BMPRII and type II Activin receptors ACVR2A and ACVR2B, they interact with overlapping TGF-β family ligands to activate either the SMAD 1/5/8 or SMAD 2/3 signaling. In the pulmonary vasculature, the BMP-9 ligand regulates cell proliferation by binding to type I receptors, ALK-1 and BMPRII, to activate SMAD 1/5/8 signaling. In PAH, there is a decrease in SMAD 1/5/8 signaling and an increase in SMAD 2/3 signaling. However, what causes the signaling switch is still unknown. In our lab, we found out that BMPRII and ACVR2A bind TGF-β ligands with nearly identical geometry based on our crystal structures. Both of the receptors contain a conserved hydrophobic hot spot within the ligand binding pocket. We found that the BMPRII ligand binding domain may exhibit greater flexibility than ACVR2A. We also investigated eight soluble BMPRII extracellular domain mutants and expressed them as BMPRII-Fc fusion proteins (BMPRII-Fc variants). Using surface plasmon resonance, we observed four of the BMPRII-Fc variants bind to high affinity ligands, such as BMP9, BMP10, Activin B and Activin A. In reporter gene assays, we found these BMPRII-Fc variants act as a ligand trap and attenuate BMP9 and BMP10-mediated SMAD1/5/8 signaling in HEK293 cells. Interestingly, they did not inhibit Activin B-mediated SMAD2/3 signaling. In conclusion, our findings show gain of function of specific BMPRII mutations and suggest that imbalances between SMAD1/5/8 and SMAD2/3 signaling may lead to PAH progression.

Evolving Concepts in Endothelial Pathobiology of Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a deadly disease, characterized by increased vascular resistance, pulmonary arteriolar loss, and occlusive arterial remodeling, leading to eventual right heart failure. Evidence increasingly points to the pulmonary endothelium as a central actor in PAH. Endothelial cell apoptosis can result directly in distal lung arteriolar pruning and indirectly in the formation of complex and occlusive arterial lesions, reflecting an imbalance between endothelial injury and repair in the development and progression of PAH. Many of the mutations implicated in PAH are in genes, which are predominantly, or solely, expressed in endothelial cells, and the endothelium is a major target for therapeutic interventions to restore BMP signaling. We explore how arterial pruning can promote the emergence of occlusive arterial remodeling mediated by ongoing endothelial injury secondary to hemodynamic perturbation and pathological increases in luminal shear stress. The emerging role of endothelial cell senescence is discussed in the transition from reversible to irreversible arterial remodeling in advanced PAH, and we review the sometimes conflicting evidence that female sex hormones can both protect or promote vascular changes in disease. Finally, we explore the contribution of the endothelium to metabolic changes and the altered inflammatory and immune state in the PAH lung, focusing on the role of excessive TGFβ signaling. Given the complexity of the endothelial pathobiology of PAH, we anticipate that emerging technologies that allow the study of molecular events at a single cell level will provide answers to many of the questions raised in this review.

Potential role of cellular senescence in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a rare and chronic lung vasculature disease characterised by pulmonary vasculature remodelling, including abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) and dysfunctional endothelial cells (ECs). Remodelling of the pulmonary vasculature occurs from maturity to senescence, and it has become apparent that cellular senescence plays a central role in the pathogenesis of various degenerative vascular diseases and pulmonary pathologies. Cellular senescence represents a state of stable proliferative arrest accompanied by the senescence-associated secretory phenotype (SASP), which entails the copious secretion of proinflammatory signals in the tissue microenvironment. Evidence shows that in PAH patients, higher levels of cytokines, chemokines and inflammatory mediators can be detected and correlate with clinical outcome. Moreover, senescent cells accrue with age in epithelial, endothelial, fibroblastic and immunological compartments within human lungs, and evidence has shown that ECs and PASMCs in lungs from patients with chronic obstructive pulmonary disease were characterised by a higher number of senescent cells. However, there is little evidence uncovering the molecular pulmonary vasculature senescence in PAH. Herein, we review the cellular senescence in pulmonary vascular remodelling, and emphasise its importance in PAH. We further introduce some signalling pathways which might be involved in vasculature senescence and PAH, with the intent to discuss the possibility of the PAH therapy via targeting cellular senescence and reduce PAH progression and mortality.

Proteomic and Metabolomic Analyses of Right Ventricular Failure due to Pulmonary Arterial Hypertension.

Right ventricular failure (RVF) is the independent and strongest predictor of mortality in pulmonary arterial hypertension (PAH), but, at present, there are no preventive and therapeutic strategies directly targeting the failing right ventricle (RV). The underlying mechanism of RV hypertrophy (RVH) and dysfunction needs to be explored in depth. In this study, we used myocardial proteomics combined with metabolomics to elucidate potential pathophysiological changes of RV remodeling in a monocrotaline (MCT)-induced PAH rat model. The proteins and metabolites extracted from the RV myocardium were identified using label-free liquid chromatography–tandem mass spectrometry (LC-MS/MS). The bioinformatic analysis indicated that elevated intracellular Ca2+ concentrations and inflammation may contribute to myocardial proliferation and contraction, which may be beneficial for maintaining the compensated state of the RV. In the RVF stage, ferroptosis, mitochondrial metabolic shift, and insulin resistance are significantly involved. Dysregulated iron homeostasis, glutathione metabolism, and lipid peroxidation related to ferroptosis may contribute to RV decompensation. In conclusion, we depicted a proteomic and metabolomic profile of the RV myocardium during the progression of MCT-induced PAH, and also provided the insights for potential therapeutic targets facilitating the retardation or reversal of RV dysfunction in PAH.

Pirfenidone ameliorates pulmonary arterial pressure and neointimal remodeling in experimental pulmonary arterial hypertension by suppressing NLRP3 inflammasome activation.

Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased pulmonary arterial pressure, inflammation, and neointimal remodeling of pulmonary arterioles. Serum levels of interleukin (IL)‐1β and IL‐18 are elevated in PAH patients and may enhance proinflammatory neointimal remodeling. NLRP3 inflammasome activation induces cleavage of the cytokines IL‐1β and IL‐18, required for their secretion. Pirfenidone (PFD), an antifibrotic and anti‐inflammatory drug, has been suggested to inhibit NLRP3 inflammasome activation. We hypothesized that PFD delays the progression of PAH by suppressing NLRP3 inflammasome activation. We assessed the effects of PFD treatment in a rat model for neointimal PAH induced by monocrotaline and aortocaval shunt using echocardiographic, hemodynamic, and vascular remodeling parameters. We measured inflammasome activation by NLRP3 immunostaining, Western blots for caspase‐1, IL‐1β, and IL‐18 cleavage, and macrophage IL‐1β secretion. PFD treatment ameliorated pulmonary arterial pressure, pulmonary vascular resistance, and pulmonary vascular remodeling in PAH rats. In PAH rats, immunostaining of NLRP3 in pulmonary arterioles and caspase‐1, IL‐1β, and IL‐18 cleavage in lung homogenates were increased compared to controls, reflecting NLRP3 inflammasome activation in vivo. PFD decreased IL‐1β and IL‐18 cleavage, as well as macrophage IL‐1β secretion in vitro. Our studies show that PFD ameliorates pulmonary hemodynamics and vascular remodeling in experimental PAH. Although PFD did not affect all NLRP3 inflammasome parameters, it decreased IL‐1β and IL‐18 cleavage, the products of NLRP3 inflammasome activation that are key to its downstream effects. Our findings thus suggest a therapeutic benefit of PFD in PAH via suppression of NLRP3 inflammasome activation.

Quantitative and qualitative analysis of pulmonary arterial hypertension fibrosis using wide-field second harmonic generation microscopy.

We demonstrated that wide-field second harmonic generation (SHG) microscopy of lung tissue in combination with quantitative analysis of SHG images is a powerful tool for fast and label-free visualization of the fibrosis pathogenesis in pulmonary arterial hypertension (PAH). Statistical analysis of the SHG images revealed changes of the collagen content and morphology in the lung tissue during the monocrotaline-induced PAH progression in rats. First order statistics disclosed the dependence of the collagen overproduction on time, the second order statistics indicated tightening of collagen fiber network around blood vessels and their spreading into the alveolar region. Fourier analysis revealed that enhancement of the fiber orientation in the collagen network with PAH progression was followed with its subsequent reduction at the terminating phase of the disease. Proposed approach has potential for assessing pulmonary fibrosis in interstitial lung disease, after lung(s) transplantation, cancer, etc.

Bioinformatic analysis of dysregulated circular RNAs in pediatric pulmonary hypertension linked congenital heart disease.

BackgroundCircular RNAs (circRNAs) may play important roles in the progression of pulmonary arterial hypertension. However, the potential roles they play in childhood pulmonary arterial hypertension associated congenital heart disease (CHD) progression remains unclear.MethodsThirteen human plasma samples including eight from pulmonary arterial hypertension secondary to CHD patients and five from a control group were analyzed using the Arraystar Human circRNA array. The relative expression levels of five differentially expressed circRNAs in pulmonary arterial hypertension were detected using real-time polymerase chain reaction (PCR) analysis. In parallel, these levels were also taken on control samples from 32 CHD patients. We used miRanda and TargetScan software packages to predict potential microRNA (miRNA)targets, which were then combined into a circRNA–miRNA–messenger RNA (mRNA) network.ResultsTwenty-seven circRNAs (three upregulated and 24 downregulated) were differentially expressed between the pulmonary arterial hypertension and control groups. Compared to control group levels, circ_003416 expression in the pulmonary arterial hypertension group was significantly downregulated, while circ_005372 expression, in contrast, was significantly upregulated. The differential expression of these circRNAs was mainly linked to variation in levels of oxidative phosphorylation and tight junction signaling.ConclusionsWe identified one overexpressed and one underexpressed circRNA in plasma samples from children with CHD associated pulmonary arterial hypertension. Bioinformatic analysis indicated these dysregulated circRNAs might be associated with the occurrence and regulation of pulmonary arterial hypertension.

The MFF-SIRT1/3 axis, regulated by miR-340-5p, restores mitochondrial homeostasis of hypoxia-induced pulmonary artery smooth muscle cells

AbstractMitochondrial dynamics and quality control play a central role in the maintenance of the proliferation–apoptosis balance, which is closely related to the progression of pulmonary arterial hypertension (PAH). However, the exact mechanism of this balance remains unknown. Pulmonary artery smooth muscle cells (PASMCs) were cultured in hypoxia condition for constructing a PAH model in vitro. The expression of genes and proteins were determined by qRT-PCR and western bolt assays. Cell proliferation–apoptosis balance were tested by MTT, EdU and TUNEL assays. The mitochondrial functions were assessed by flow cytometry, JC-1, Mito tracker red staining, and corresponding kits. Besides, the molecular interaction was validated by dual-luciferase reporter assay. MFF was overexpressed in hypoxia-treated PAMSCs. Knockdown of MFF significantly repressed the excessive proliferation but enhanced cell apoptosis in hypoxia-treated PAMSCs. Moreover, MFF silencing improved mitochondrial function of hypoxia-treated PAMSCs by increasing ATP production and decreasing ROS release and mitochondrial fission. Mechanistically, MFF was a directly target of miR-340-5p, and could negatively regulate SIRT1/3 expression. Subsequently, functional rescue assays showed that the biological effects of MFF in hypoxia-treated PAMSCs were negatively regulated by miR-340-5p and depended on the regulation on SIRT1/3 pathway. These results provided evidences that miR-340-5p regulated MFF-SIRT1/3 axis to improve mitochondrial homeostasis and proliferation–apoptosis imbalance of hypoxia-treated PAMSCs, which provided a theoretical basis for the prevention and treatment of PAH.The imbalance between the proliferation and apoptosis of pulmonary arterial smooth muscle cells (PASMCs) is an important pathological process in pulmonary arterial hypertension (PAH). Mitochondrial dynamics and quality control play important roles in maintaining the cell proliferation–apoptosis balance. This paper reveals that miR-340-5p upregulates SIRT1/3 by targeting MFF, therefore improving mitochondrial dysfunction to maintain the proliferation–apoptosis balance of hypoxia-treated PAMSCs.

Clinical value of lncRNA SOX2-OT in pulmonary arterial hypertension and its role in pulmonary artery smooth muscle cell proliferation, migration, apoptosis, and inflammatory

BackgroundNon-coding RNA is confirmed to be involved in pulmonary arterial hypertension (PAH). ObjectivesThis study investigated the clinical value and potential mechanisms of the long noncoding RNA (lncRNA) SRY-box transcription factor 2 overlapping transcript (SOX2-OT) in PAH. MethodsSOX2-OT levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) in serum of 82 patients with PAH and 76 healthy controls. Receiver operating characteristic (ROC) analysis was performed to assess the diagnostic value of SOX2-OT. Human pulmonary arterial smooth muscle cells (hPASMCs) were treated by hypoxia to construct PAH cell models. Proliferation, migration, apoptosis, and inflammatory cytokines levels of hPASMCs were examined by CCK-8, Transwell, flow cytometry, and ELISA assay. Dual-luciferase reporter gene assays were performed to verify the target relationships between miR-455-3p and SOX2-OT, as well as small ubiquitin-related modifier 1 (SUMO1). ResultsSerum SOX2-OT was highly expressed in patients with PAH (P < 0.05). And elevated SOX2-OT levels significantly differentiated PAH patients from healthy controls, confirming high diagnostic feasibility. What's more, SOX2-OT was increased in hypoxia-induced hPASMCs in a time-dependent manner. Silencing SOX2-OT could reverse hypoxia-induced proliferation, migration, anti-apoptosis, and inflammation of hPASMCs (P < 0.05). However, rescue experiments showed that this reversal effect of silencing SOX2-OT was attenuated by suppressed miR-455-3p, which was presumably achieved by SUMO1 (P < 0.05). ConclusionsElevated SOX2-OT is a feasible diagnostic marker for PAH, and its silencing may attenuated hypoxia-induced hPASMCs proliferation, migration, anti-apoptosis, and inflammation by modulating the miR-455-3p/SUMO1 axis, preventing vascular remodeling and PAH progression. Our research provided new insights for PAH treatment.

Long Term Safety and Outcomes Utilizing the CardioMEMS Device in Patients with Pulmonary Arterial Hypertension

<h3>Purpose</h3> Baseline and periodic hemodynamic monitoring of pulmonary artery pressures using right heart catheterization (RHC) is recommended for initiating and titrating pulmonary arterial hypertension (PAH) therapies as well as for prognostication. The CardioMEMS HF System is an ambulatory implantable hemodynamic monitor, previously only used in patients with left heart failure (HF). In this study, we describe the long-term safety and outcomes using the CardioMEMS device in PAH patients implanted as a part of an investigational pilot study. <h3>Methods</h3> 23 PAH patients between the ages of 31-80 years, were implanted with CardioMEMS device as a part of an investigational pilot study (VITA contract HHSN268201400008C) between 08/2014 - 09/2018. 3 patients were lost to follow-up. Complete follow up data was available for 20 patients who were included in this analysis. <h3>Results</h3> 85% of the PAH patients were female, with a median post-implant follow-up period of 58.5 months. The number of right heart catheterization (RHC) prior to the device implant was 4.37 per patient year, while only 1.99 RHC per patient year were done post implant. In long term follow up there were no significant device related adverse events and all devices remain functional. 8 patients did require RHC for recalibration of the device. 12 patients are still undergoing active monitoring. Of the remaining patients, 1 was enrolled in hospice, 4 patients died from progression of PAH, 1 patient died from malignancy; 1 from end-stage cirrhosis. There was a total of 13 HF hospitalizations between these 20 patients over 3 to 7 year follow-up based on the time of implant. <h3>Conclusion</h3> The CardioMEMS device has previously been reported to reduce hospitalizations in patients with left sided heart failure. Based on our study, deployment of the device was safe in PAH patients with no long-term device related complications. It reduced the number of follow-up invasive RHC by more than 50%. Larger prospective studies are warranted before widespread use of the device for monitoring PA pressures in PAH patients.

Pirfenidon Prevents Experimental Flow-Associated PAH by Suppression of the NLRP3 Inflammasome

<h3>Purpose</h3> Pulmonary arterial hypertension (PAH) is a fatal disease with characteristic vascular remodeling, including fibrosis, within an inflammatory milieu in the distal pulmonary vascular bed. Interleukin (IL)-1β and IL-18 levels, two potent proinflammatory cytokines, are elevated in patient serum and animal models of PAH. The release of these cytokines is regulated by the activation of the NLRP3 inlfammasome, hallmarked by caspase-1 cleavage. We hypothesized that pirfenidone (PFD) an antifibrotic and antinflammatory agent delays the progression of PAH by suppressing NLRP3 inflammasome activation. <h3>Methods</h3> We investigated the effect of preventive PFD treatment in the rat model for neointimal PAH induced by monocrotaline and aortocaval shunt. The disease severity was assessed by pulmonary hemodynamics and histology. The NLRP3 inflammasome activation was assessed by immunohistochemisry and immunoblotting on lung homogenate. For proof of concept, the effect of PFD on NLRP3 inflammasome was additionally tested, by qPCR and ELISA, on bone marrow derived macrophages (BMDMs) after LPS/nigericin stimulation. <h3>Results</h3> Inflammasome activation was increased in the model compared to control as assessed by cleavage the ratio of caspase-1 (145%, p=0.023), IL-1β (142%, p=0.002) and IL-18 (210%, p=0.006). PFD treatment led to reduction of mPAP and occlusion (mPAP:28 ±8 mmHg vs 36 ±4mmHg, p=0.004; occlusion 28 ±4% vs 18 ±10%, p=0.008). So did the level of IL-1β and IL-18 activation when compared to the PAH untreated group (35%, p=0.027; 68%, p=0.005). The perivascular collagen content correlated with mPAP (p=0.025) and occlusion (p<0.001) regarding fibrosis. On BMDMs, both the inflammasome related gene expression relative to control and the IL-1β excretion were reduced by PFD (NLRP3: 40% p<0.001; IL-1β: 61% p<0.001; IL-18: 50% p<0.001 & IL-1β in medium: 44% p<0.001). <h3>Conclusion</h3> Inflammasome is activated in experimental flow-associated PAH, based on the cleavage of caspase-1 and its products IL-1β and IL-18. Its activation correlates with pulmonary hemodynamics and vascular remodeling. PFD suppresses NLRP3 inflammasome activation and ameliorates PAH, assessed by pulmonary hemodynamics and vascular remodeling.

Prostacyclin for Pulmonary Arterial Hypertension

Prostacyclin for Pulmonary Arterial Hypertension

Decrease in LINC00963 attenuates the progression of pulmonary arterial hypertension via microRNA-328-3p/profilin 1 axis.

BackgroundPulmonary arterial hypertension (PAH) is a severe cardiopulmonary disease characterized by vascular hyperplasia and remodeling. Long noncoding RNA LINC00963 can regulate cell proliferation and metastasis in nonsmall cell lung cancer. However, the function of LINC00963 on PAH progression is rarely reported.MethodsQuantitative real‐time PCR was used to determine the expression levels of LINC00963, microRNA (miRNA)‐328‐3p, and profilin 1 (PFN1), as well as vascular endothelial growth factor (VEGF), fibroblast growth factor 2 (FGF‐2), and hypoxia‐inducible factor (HIF)‐α. The protein level of PFN1 was measured by western blotting. The viability and migration of hypoxia‐induced pulmonary arterial smooth muscle cells (PASMCs) were assessed by 3‐(4, 5‐dimethyl‐2‐thiazolyl)‐2, 5‐diphenyl‐2‐h‐tetrazolium bromide, and transwell assays, respectively. The target relationships between miR‐328‐3p and LINC00963/PFN1 were confirmed by dual‐luciferase reporter assay. A PAH mouse model was conducted to explore the effects of hypoxia on cardiopulmonary functions.ResultsIn hypoxia‐induced PASMCs and PAH mouse model, high expression levels of LINC00963 and PFN1, and low expression of miR‐328‐3p, were determined. The viability, migration of hypoxia‐induced PASMCs, the expression of VEGF, FGF‐2, and HIF‐α were significantly repressed by transfection of si‐LINC00963 or miR‐328‐3p mimics. The inhibitory effects of LINC00963 silencing on cell viability, migration, and the levels of VEGF, FGF‐2, and HIF‐α were partly eliminated by miR‐328‐3p inhibitor or increasing the expression of PFN1. Hypoxia treatment increased the levels of RVSP, mPAP, and RV/(LV+S), as well as the thickness of pulmonary artery wall.ConclusionsSilencing of LINC00963 ameliorates PAH via modulating miR‐328‐3p/PFN1.

Immune Cells in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a complex and serious cardiopulmonary disease; it is characterised by increased pulmonary arterial pressure and pulmonary vascular remodelling accompanied by disordered endothelial and smooth muscle cell proliferation within pulmonary arterioles and arteries. Although recent reports have suggested that dysregulated immunity and inflammation are key players in PAH pathogenesis, their roles in PAH progression remain unclear. Intriguingly, altered host immune cell distribution, number, and polarisation within the lung arterial vasculature have been linked to disease development. This review mainly focusses on the roles of different immune cells in PAH and discusses the underlying mechanisms.

Perillyl alcohol and quercetin modulate the expression of non-coding RNAs MIAT, H19, miR-29a, and miR-33a in pulmonary artery hypertension in rats.

BackgroundNon-coding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), play critical roles in the pathogenesis and progression of pulmonary artery hypertension (PAH). LncRNA H19, myocardial infarction-associated transcript (MIAT), miR-29a, and miR-33a have been suggested as potential targets for treating arterial hypertension. We explored the expression pattern of non-coding RNAs H19, MIAT, miR-29a, and miR-33a in monocrotaline (MCT)-induced PAH rats. Moreover, we investigated whether perillyl alcohol (PA) and quercetin (QS), two plant derivatives with beneficial effects on PAH-induced abnormalities, act through regulating the expression of these non-coding RNAs.MethodsMale Wistar rats (n = 30) were divided into five groups. MCT (60 mg/kg) was injected subcutaneously to induce PAH. PA (50 mg/kg daily) and QS (30 mg/kg daily) were administered three weeks after induction of PAH. H&E staining and qRT-PCR were performed to assess arteriole wall thickness and gene expression, respectively.ResultsRight ventricular systolic pressure (RVSP) and right ventricular hypertrophy (RVH) increased in MCT and MCT + Veh. groups compared to the control group (in both P < 0.001). QS and PA decreased RVSP and RVH significantly. Wall thickness and fibrosis score in the MCT group (score 3) increased compared to the control group (score 0). PA and QS ameliorated wall thickness and fibrosis to score 1 (mild). Also, the expression of miR-29a and miR-33a decreased in the PAH group (in both, P < 0.001). Treatment with PA and QS decreased the expression of H19 (P < 0.001) and MIAT (P < 0.01) and increased the expression of miR-29a (P < 0.01) and miR-33a significantly (P < 0.05 for QS and P < 0.001 for PA).ConclusionsThe beneficial effects of PA and QS on PAH-induced abnormalities were exerted through returning the dysregulated expression of H19, MIAT, miR-29a, and miR-33a to normal levels in rats with MTC-induced PAH. This study emphasized the therapeutic potential of PA and QS in PAH. However, more detailed investigations are needed to clarify the underlying molecular mechanisms.

FGF21 attenuates pulmonary arterial hypertension via downregulation of miR-130, which targets PPARγ.

The proliferation, migration and apoptotic resistance of pulmonary artery smooth muscle cells (PASMCs) are central to the progression of pulmonary arterial hypertension (PAH). Our previous study identified that fibroblast growth factor 21 (FGF21) regulates signalling pathway molecules, such as peroxisome proliferator‐activated receptor gamma (PPARγ), to play an important role in PAH treatment. However, the biological roles of miRNAs in these effects are not yet clear. In this study, using miRNA sequencing and real‐time PCR, we found that FGF21 treatment inhibited miR‐130 elevation in hypoxia‐induced PAH in vitro and in vivo. Dual luciferase reporter gene assays showed that miR‐130 directly negatively regulates PPARγ expression. Inhibition of miR‐130 expression suppressed abnormal proliferation, migration and apoptotic resistance in hypoxic PASMCs, and this effect was corrected upon PPARγ knockdown. Both the ameliorative effect of FGF21 on pulmonary vascular remodelling and the inhibitory effect on proliferation, migration and apoptotic resistance in PASMCs were observed following exogenous administration of miR‐130 agomir. In conclusion, this study revealed the protective effect and mechanism of FGF21 on PAH through regulation of the miR‐130/PPARγ axis, providing new ideas for the development of potential drugs for PAH based on FGF21.

Caspase-4/11-Mediated Pulmonary Artery Endothelial Cell Pyroptosis Contributes to Pulmonary Arterial Hypertension.

Endothelial dysfunction enhances vascular inflammation, which initiates pulmonary arterial hypertension (PAH) pathogenesis, further induces vascular remodeling and right ventricular failure. Activation of inflammatory caspases is an important initial event at the onset of pyroptosis. Studies have shown that caspase-1-mediated pyroptosis has played a crucial role in the pathogenesis of PAH. However, the role of caspase-11, another inflammatory caspase, remains to be elucidated. Therefore, the purpose of this study was to clarify the role of caspase-11 in the development of PAH and its mechanism on endothelial cell function. The role of caspase-11 in the progression of PAH and vascular remodeling was assessed in vivo. In vitro, the effect of caspase-4 silencing on the human pulmonary arterial endothelial cells pyroptosis was determined. We confirmed that caspase-11 and its human homolog caspase-4 were activated in PAH animal models and TNF (tumor necrosis factor)-α-induced human pulmonary arterial endothelial cells. Caspase-11-/- relieved right ventricular systolic pressure, right ventricle hypertrophy, and vascular remodeling in Sugen-5416 combined with chronic hypoxia mice model. Meanwhile, pharmacological inhibition of caspase-11 with wedelolactone exhibited alleviated development of PAH on the monocrotaline-induced rat model. Moreover, knockdown of caspase-4 repressed the onset of TNF-α-induced pyroptosis in human pulmonary arterial endothelial cells and inhibited the activation of pyroptosis effector GSDMD (gasdermin D) and GSDME (gasdermin E). These observations identified the critical role of caspase-4/11 in the pyroptosis pathway to modulate pulmonary vascular dysfunction and accelerate the progression of PAH. Our findings provide a potential diagnostic and therapeutic target in PAH.

Potential of the TRPM7 channel as a novel therapeutic target for pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.