Search Results (167)

Local immune cell activation and vascular remodelling are characteristic pathogenic features of pulmonary arterial hypertension (PAH). HIV and schistosome infections have been individually associated with PAH. However, whether co-infection with these pathogens has a distinct impact on the development of pulmonary vascular disease remains poorly understood, partly due to the lack of experimental animal models. In a novel non-infectious model of HIV and Schistosoma pulmonary co-exposure based on lung embolisation of S. mansoni eggs in HIV-transgenic (HIV) mice, we previously reported exacerbated endothelial remodelling and dysfunction, along with increased pulmonary arterial pressure; which were associated with a unique profile of pro-inflammatory cytokines in the lung. In the present study, we used flow cytometric analysis of isolated lung leukocytes and immunofluorescence staining to characterise the pulmonary immune cell landscape associated with individual or combined exposure to HIV and schistosome. Compared with mice exposed to HIV (untreated HIV mice) or schistosome (egg-treated wild-type mice), co-exposed (egg-treated HIV mice) animals showed significantly increased numbers of interstitial and alveolar macrophages, patrolling-type monocytes, NKT and γδ T cells, and reduced CD8⁺ αβ T cells. Other lung immune cells, including inflammatory-type monocytes, eosinophils/neutrophils, dendritic cells, CD4⁺ αβ T cells, NK cells and B cells were not significantly affected in the co-exposure condition. Taken together, these results show for the first time that combined pulmonary exposure to HIV and Schistosoma, as it may occur in co-infected individuals, alters the local immune cell landscape in a manner distinct from that of individual exposure. Furthermore, these findings may contribute to a better understanding of the complex inflammatory processes involved in the pathogenesis of PAH, thereby supporting the development of therapies targeting pathogenic immune cells in pulmonary vascular disease associated with HIV and Schistosoma co-morbidity. Full article

Endothelial dysfunction is a key characteristic of many diseases, including atherosclerosis, hypertension, heart failure, stroke, cancer, acute respiratory distress syndrome (ARDS), peripheral vascular disease, coronavirus 2019 (COVID-19), and pulmonary arterial hypertension (PAH). To improve understanding of the roles of endothelial cells (ECs) in health and disease, EC-specific genome editing technologies have been developed in recent years. Therapeutic strategies that aim to restore a healthy endothelial monolayer include the inhibition of endothelial genes that cause EC injury and dysfunction and the induction or activation of endothelial genes that drive EC repair and regeneration. In this review, we describe established recombinase-mediated genetic modification technologies and emerging EC-specific genome editing technologies including viral and non-viral delivery of the CRISPR/Cas9 genome editing system, and we summarize the strengths and limitations of each technology. We then discuss possible avenues for future research, including the development of organ-specific EC genome editing technologies. In short, EC-specific genome editing technologies can be used to modulate gene expression selectively in ECs and even within a specific vascular bed and/or distinctive EC subtype, and, in doing so, greatly improve the understanding of vascular biology and help develop precision genetic medicine targeting the disease-causing vascular bed(s) to effectively treat diseases caused by vascular endothelial dysfunction. Full article

Pulmonary arterial hypertension (PAH) is a chronic and progressive cardiopulmonary vascular disorder associated with poor clinical prognosis. Its hallmark pathological feature is sustained elevation of pulmonary vascular resistance resulting from extensive vascular remodeling. Endothelial-to-mesenchymal transition (EndMT), a critical event driving vascular remodeling, is increasingly recognized as central to PAH development and progression. This review systematically outlines the convergence of multiple pathophysiological insults on endothelial dysfunction and intimal remodeling in PAH, highlighting their roles in initiating EndMT. Principal factors include: (1) genetic and molecular alterations, such as BMPR2 mutations and epigenetic dysregulation; (2) environmental and toxic exposures, including chronic hypoxia and anorexigens; (3) inflammatory and immune dysregulation, exemplified by chronic inflammatory infiltrates and autoimmune conditions; and (4) hemodynamic and metabolic disturbances, notably aberrant shear stress and lipid metabolic imbalance. Given the critical contribution of EndMT to PAH pathogenesis, therapeutic strategies aimed at reversing EndMT represent promising anti-remodeling interventions. Preclinical studies have begun exploring EndMT-targeted therapies, including mesenchymal stem cell (MSC) transplantation and dipeptidyl peptidase-4 (DPP-4) inhibitors. Herein, we summarize recent advances regarding EndMT in PAH, dissect the molecular drivers and modulators initiating and sustaining EndMT, and critically evaluate emerging therapeutic strategies harnessing this pathway for clinical benefit. Full article

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease of the pulmonary vasculature characterized by obliterative remodeling of small pulmonary arteries, leading to sustained elevation of pulmonary vascular resistance, right ventricular failure, and premature death. The diagnostic gold standard remains right heart catheterization, requiring a mean pulmonary artery pressure greater than 20 mmHg at rest, a pulmonary arterial wedge pressure of 15 mmHg or below, and a pulmonary vascular resistance exceeding 2 Wood units. PAH is an autosomal dominant disorder with markedly incomplete penetrance of approximately 20–30%, indicating that germline mutations alone are insufficient to cause disease. Disease manifestation requires additional “second hits”, including chronic hypoxia, systemic inflammation, hemodynamic stress, hormonal influences, and common genetic modifiers such as single-nucleotide polymorphisms (SNPs). This genetic and environmental complexity underpins the broad clinical heterogeneity observed across PAH subtypes, which include idiopathic PAH, heritable PAH, and disease associated with connective tissue disorders, HIV infection, portal hypertension, congenital heart disease, schistosomiasis, and drug or toxin exposure. This review provides a comprehensive and critical appraisal of the molecular-genetic architecture of PAH. Thirty genes have now been implicated in disease pathogenesis, spanning seven functional categories: receptors of the TGF-β/BMP signaling family (BMPR2, ACVRL1, ENG, BMPR1B); circulating BMP ligands (GDF2, BMP10); transcription factors (TBX4, SOX17, KLF4, FOXF1, SMAD1, SMAD4, SMAD9); membrane and polyamine transporters (ATP13A3, AQP1); potassium channel regulators (KCNA5, KCNK3, ABCC8); metabolic and mitochondrial genes (EIF2AK4, NFU1, GGCX); signaling receptors and structural proteins (NOTCH3, KDR, CAV1, PLEKHH2); vasoactive and extracellular matrix regulators (KLK1, CBLN2, CD248); and epigenetic regulators (TET2, TOPBP1). Among these, BMPR2 is the dominant contributor, accounting for 53–86% of heritable PAH and 14–35% of idiopathic cases. The remaining genes each account for fewer than 5% of cases individually, collectively reflecting a broad landscape of rare and ultra-rare genetic contributions. For each gene, we critically evaluate the strength of genetic evidence, pathogenic mechanisms, degree of mechanistic resolution, and clinical relevance. We further discuss the contribution of emerging technologies, including whole-genome sequencing, single-cell and spatial transcriptomics, multi-omics integration, iPSC-derived vascular models, and artificial intelligence, to expanding the PAH genetic architecture beyond single-gene discovery. A key theme across this landscape is convergence: despite mechanistic diversity at the gene level, most PAH-associated variants ultimately impair endothelial quiescence, promote smooth muscle proliferation, and drive apoptosis resistance through disruption of BMP signaling amplitude, transcriptional stability, ion channel homeostasis, metabolic integrity, or epigenetic regulation. This convergence supports both a unified therapeutic rationale and a precision medicine framework for genotype-stratified intervention in PAH. Full article

Endothelial dysfunction (ED) arises in multiple pathologies, and its severity correlates with disease progression. Common ED biomarkers could provide prognostic value for associated complications. This study aims to identify shared ED biomarkers and assess their prognostic significance. Endothelial cells in culture (human microvascular endothelial cells, HMEC-1) were exposed to sera from patients in five disease groups (n = 20 patients/group)—liver cirrhosis with portal hypertension, idiopathic pulmonary arterial hypertension, placental disorders such as intrauterine growth restriction, coronary artery disease with acute myocardial infarction, and chronic kidney disease—or matched controls, in the absence/presence of anti-inflammatory (apixaban) and antioxidant (EUK134) compounds. We explored changes in: VCAM-1, ICAM-1, eNOS, VWF, extracellular matrix thrombogenicity, and reactive oxygen species (ROS). In serum samples, proteomics and metabolomics analyses (including lipids, amino acids, and polar metabolites) were performed through an extraction protocol to identify common ED biomarkers. Expression of VCAM-1, ICAM-1, VWF, platelet adhesion, and ROS increased in most groups versus controls (p < 0.05). Both drugs decreased all biomarker levels except eNOS (n = 6 for in vitro experiments). For serum ED biomarkers, 18 metabolites and 24 proteins showed AUC-ROC and hit rates >77.5%, and six metabolites were associated with event-free survival. These diseases share ED driven by systemic inflammatory, oxidative, and metabolic stress, are partially reversible in vitro, and are linked to biomarkers associated with clinical outcomes. Overall, ED emerges as a modifiable pathological axis with potential prognostic value. Full article

Pulmonary arterial hypertension (PAH) is a severe and progressive cardiopulmonary disorder with limited treatment options. Camellia petelotii (Merr.) Sealy (CP) contains multiple flavonoids and other phytochemicals, but its active compounds and molecular mechanisms in PAH remain unclear. Active compounds of CP were screened by comprehensive literature mining and absorption, distribution, metabolism, and excretion (ADME) evaluation. PAH-related hub targets were identified from transcriptomic data using weighted gene co-expression network analysis (WGCNA), machine learning, and external validation. Functional enrichment, immune infiltration, and single-cell RNA-sequencing analyses were performed to characterize their biological roles and cellular localization. Molecular docking and molecular dynamics simulations assessed compound–target interactions. The effects of CP were further evaluated in hypoxia-induced rat pulmonary artery smooth muscle cells (RPASMCs). Five core bioactive compounds were identified, among which luteolin and quercetin were prioritized for further analysis. HSP90AA1 and ROCK2 were screened as hub targets. Bioinformatic analyses suggested that these targets were mainly associated with the “Lipid and atherosclerosis” pathway, metabolic reprogramming, and modulation of the immune microenvironment. Single-cell analysis showed broad expression of HSP90AA1 and enrichment of ROCK2 in fibroblasts and endothelial cells. Molecular docking and molecular dynamics simulations supported stable binding of luteolin to HSP90AA1. In vitro, CP extract inhibited hypoxia-induced hyperproliferation of RPASMCs and reduced HSP90AA1 protein expression. HSP90AA1 may represent a candidate molecular mediator of CP in PAH, and CP inhibited hypoxia-induced RPASMC proliferation in association with downregulation of HSP90AA1. Full article

The lung–kidney axis forms an important physiologically integrated system which controls multiple essential functions of the body. An important observation of this interaction is tissue oxygenation and erythropoiesis, a vital process that involves erythropoietin (EPO) release by the kidney to bring red cell production into the bone, while pulmonary gas exchange ensures adequate oxygen delivery to the cells. Subsequently, the lung–kidney activation of the renin angiotensin system (RAS) influences vascular tone, blood pressure, and tissue perfusion, influencing the delivery of oxygen and the body’s requirement for erythropoietin. Additionally, beyond oxygen sensing, studies have evidenced the role of hypoxia-inducible factors (HIFs), inflammatory mediators, endothelial signaling pathways and iron availability. These modulate erythropoietin production, which enhances the process of erythropoiesis and arterial oxygen balance. Localized variations in renal oxygen levels together with hemodynamic control mechanisms enable the body to produce erythropoietin independently from systemic hypoxia conditions. This concept emerged to include the renal oxygen extraction fraction (OFE) and intrarenal microvascular shunting with perfusion oxygen coupling in governing EPO production. The present review refines the traditional knowledge to further expand our understanding of the lung–kidney axis regulating the process of erythropoiesis and arterial oxygen content. The integrative framework demonstrates that pulmonary arterial oxygenation and renal oxygen sensing together with bone hematopoietic responses operate as a unified system which maintains both oxygen equilibrium and hematopoietic balance throughout the body. Full article

Pulmonary endarterectomy (PEA) specimens provide a unique source of endothelial cells (ECs) to model chronic thromboembolic pulmonary hypertension (CTEPH) in vitro. This study investigates the impact of chronic hypoxia on PEA-derived ECs, focusing on mechanisms of endothelial dysfunction and vascular remodeling. ECs from PEA specimens (EC-CTEPH) and controls were exposed to normoxia, hypoxia, and reoxygenation. Cell morphology, proliferation, migration, and expression of angiogenic and hypoxia-responsive genes were assessed. Pharmacological HIF stabilization with dimethyloxalylglycine (DMOG) was compared with hypoxia. Oxidative stress responses were evaluated using hydrogen peroxide. EC-CTEPH showed impaired adaptation to hypoxia, with reduced induction of glycolytic and angiogenic genes, altered morphology, delayed wound closure, and persistent oxidative stress after reoxygenation, consistent with defective hypoxia sensing. DMOG partially restored metabolic gene expression, indicating improved adaptation through HIF stabilization. Despite elevated basal ROS levels, oxidative challenge did not trigger adaptive glycolytic or angiogenic responses and induced distinct transcriptional profiles compared with controls. CTEPH endothelial cells display an altered response to hypoxia and oxidative stress, consistent with impaired hypoxia sensing and stress adaptation. This model highlights maladaptive endothelial features and provides a framework for future studies exploring HIF-targeted approaches in CTEPH. Full article

The interaction between Angiostrongylus vasorum and the vascular endothelium of the host plays a key role in the pathogenesis of canine angiostrongylosis. The adult stage of A. vasorum resides in right ventricles and pulmonary arteries of dogs and foxes and maintains close contact with the endothelium, whose activation may contribute to the hemostatic and hemorrhagic disorders observed in infected animals. However, the molecular mechanisms underlying this endothelial dysfunction remain poorly understood. To investigate this interaction, an in vitro model of vascular endothelial cells was stimulated with the adult A. vasorum homogenate. Quantitative proteomic analysis, combined with bioinformatic tools, identified 691 and 6011 protein groups in the cell supernatants and the cell lysates, respectively. Of these, 213 proteins in the cell supernatants (193 up-regulated and 20 down-regulated) and 564 in the cell lysates (358 up-regulated and 206 down-regulated) showed differential expression compared to control cells. Up-regulated proteins included TFPI, CD59, VWF, ANGPT2, MMRN1, and FLT1, which are involved in endothelial activation, angio-genesis, and coagulation regulation. Conversely, C3, SERPINE1, SERPINB2, PLAU, PLAUR, and ICAM1 were down-regulated, suggesting modulation of fibrinolysis, inflammation, and cell adhesion pathways. These findings indicate that adult A. vasorum homogenate induces a multifactorial endothelial activation characterized by dysregulation of coagulation, complement, and vascular remodelling pathways. Future studies focusing on the temporal and molecular characterization of endothelial responses to excretory/secretory antigens in both definitive and accidental hosts will further clarify the mechanisms of vascular pathology and parasite tolerance. Full article

Pulmonary arterial hypertension (PAH) is characterized by dysfunction and remodeling of the pulmonary artery endothelium and smooth muscle. In heritable PAH, heterozygous loss-of-function mutations in the type II Bone Morphogenetic Protein (BMP) receptor gene (BMPR2) are the most common genetic cause. However, the mechanisms by which reduced BMPR2 levels alter endothelial signaling to drive PAH pathogenesis remain incompletely understood. To determine how BMPR2 levels govern signaling output and endothelial functional responses, we modulated BMPR2 expression in human pulmonary artery endothelial cells (PAECs) and assessed ligand-dependent SMAD1/5/8 signaling, proliferation, and caspase-3/7 activity. We found that BMP9 and BMP10 robustly activated SMAD1/5/8 signaling and promoted proliferation in PAECs, whereas the other ligands in this panel did not elicit a comparable signaling or proliferative response under these assay conditions. A moderate (~50%) reduction in BMPR2 protein levels (an in vitro approximation of haploinsufficiency) attenuated BMP9/10-induced SMAD1/5/8 activation, abolished proliferative responses, and was associated with a modest increase in caspase-3/7 activity, consistent with caspase pathway activation and early stress/injury signaling. Under BMPR2-limiting conditions, BMP9/10 responses became sensitive to Activin type II receptor blockade by bimagrumab, consistent with a context-dependent contribution of Activin type II receptors. Conversely, BMPR2 overexpression enhanced BMP9/10-dependent SMAD signaling and proliferation. Together, these findings support a receptor–dosage model where physiological BMPR2 expression is required to sustain homeostatic BMP9/10 signaling in pulmonary artery endothelium. This framework provides a basis for interpreting context-dependent pathway effects in PAH. Full article

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by endothelial dysfunction, vascular remodeling, and a sustained increase in pulmonary vascular resistance, causing cardiopulmonary damage. The apelin receptor (APJ), a member of the G protein-coupled receptor family, has emerged as an essential modulator of vascular homeostasis. Clinical and preclinical studies have demonstrated that its activation exerts beneficial effects on the progression of PAH. Its main actions include the restoration of endothelial function, reactivation of the BMPR2/SMAD axis, induction of nitric oxide-mediated vasodilation, inhibition of autophagy and the migration of the pulmonary artery smooth muscle cells (PASMCs). Furthermore, its expression and functionality are modulated by epitranscriptomic mechanisms, particularly by microRNAs involved in the post-transcriptional regulation of key genes for vascular homeostasis. These findings position the APJ as a relevant therapeutic target in PAH. However, the clinical application of its agonists still faces pharmacokinetic limitations that restrict their therapeutic use. Therefore, the aim of this review is to gather current information on APJ in the pathophysiology of PAH and focus attention on its potential as a therapeutic target. Full article

Elevated plasma lactate is a significant risk factor in pulmonary hypertension (PH), and endothelial-mesenchymal transition (EndoMT) is a major contributor to this pathological process, yet its specific role in driving endothelial-mesenchymal transition (EndoMT) remains unclear. Using in vivo and in vitro models, we demonstrate that modulating lactate levels critically influences PH progression. In a hypoxic PH mouse model, inhibition of lactate production ameliorated hemodynamic and vascular remodeling, whereas exogenous lactate exacerbated these pathologies. In human pulmonary arterial endothelial cells under hypoxia, lactate promoted a pro-remodeling phenotype, enhancing migration, proliferation, and EndoMT. Mechanistically, lactate induced Twist1 lactylation via enhanced association with p300/CBP, promoting its nuclear translocation. This upregulated TGFB1 transcription and activated the Smad2 pathway, thereby driving EndoMT—an effect abolished by Twist1 knockdown. Our findings reveal a previously unrecognized lactate-Twist1 lactylation-TGFB1 axis that promotes vascular remodeling in PH, identifying novel therapeutic targets. Full article

Pulmonary hypertension (PH) is a progressive disorder characterized by elevated pulmonary arterial pressure and the extensive remodeling of pulmonary vasculature. Chronic intermittent hypoxia (CIH), a hallmark of obstructive sleep apnea (OSA), is a well-established contributor to the pathogenesis of PH. OSA is defined by repetitive episodes of upper airway obstruction during sleep, leading to cycles of hypoxia and reoxygenation that trigger a cascade of deleterious events including oxidative stress, inflammation, endothelial dysfunction, and vascular remodeling. Growing evidence underscores the critical role of transient receptor potential canonical (TRPC) channels in mediating hypoxia-induced vascular alterations that contribute to the development of PH. TRPC channels are non-selective cation channels that regulate calcium influx in response to mechanical stimuli, pro-inflammatory cytokines, oxidative stress, and hypoxia. These channels are expressed in both pulmonary arterial smooth muscle cells (PASMCs) and pulmonary artery endothelial cells (PAECs), where they modulate key processes such as proliferation, migration, apoptosis, endothelial permeability, and vasoconstriction. Under hypoxic conditions, the upregulation of TRPC1, TRPC3, TRPC4, and TRPC6 has been implicated in dysregulation of calcium homeostasis and activation of pathological signaling pathways that contribute to increased pulmonary arterial pressure. In this review, we propose that upregulation and functional modulation of TRPC channels under CIH represents a central pathogenic mechanism linking OSA to PH. We hypothesize that TRPC1, TRPC3, TRPC4, and TRPC6 act as critical molecular effectors mediating hypoxia-driven calcium influx and downstream signaling pathways that lead to pulmonary vascular remodeling, endothelial dysfunction, and increased pulmonary arterial pressure. This framework allows us to integrate mechanistic insights from molecular, cellular, and translational studies, and to evaluate the therapeutic potential of targeting TRPC channels in OSA-associated PH. Full article

Pulmonary arterial hypertension (PAH) is characterized by progressive vascular remodeling and right ventricular (RV) dysfunction, processes that are increasingly associated with disturbances in cellular metabolism. We investigated whether transplantation of exogenous mitochondria derived from bone marrow mesenchymal stromal cells, alone or combined with sildenafil, could improve mitochondrial homeostasis and attenuate cardiopulmonary remodeling in monocrotaline-induced PAH. Male Wistar rats were assigned to control (CTRL, n = 8) or PAH (n = 32) groups. Fourteen days after induction of PAH, animals were randomized to receive saline, sildenafil (20 mg/kg/day for 14 days), intravenous mitochondrial transplantation (100 μg, days 14 and 21), or combined therapy. On day 28, echocardiography, invasive measurement of RV systolic pressure (RVSP), pulmonary vascular histology, gene expression analyses (vimentin, VE-cadherin, and mitochondrial metabolism–related genes), and high-resolution respirometry were performed. All treatments significantly reduced RVSP compared with untreated PAH. Mitochondrial therapy, alone or combined with sildenafil, decreased arteriolar α-smooth muscle actin content, whereas endothelial–mesenchymal transition was attenuated only with combined treatment. Mitochondrial transplantation and sildenafil increased Complex I–dependent respiration, whereas Complex IV activity improved exclusively with mitochondrial therapy. Combined treatment reduced plasma IL-6 and IL-1β levels compared with PAH. Thus, mitochondrial transplantation, particularly when combined with sildenafil, improved RV function, limited pulmonary vascular remodeling, reduced plasma inflammatory markers, and changed key mitochondrial pathways in experimental PAH. Full article

The transient receptor potential vanilloid 4 channel (TRPV4) is thought to play a pivotal role in pulmonary arterial circulation. The present study hypothesizes that TRPV4 activation increases nitric oxide (NO) release and activates calcium-activated potassium of intermediate conductance (KCa3.1) in pulmonary arteries. Pulmonary arteries were isolated from wild-type mice (wt) and mice deficient in KCa3.1 channels (Kcnn4^−/−) and mounted for simultaneous NO concentration and relaxation measurements. Human small pulmonary arteries were isolated and mounted in microvascular myographs for isometric tension recordings. Acetylcholine-induced increases in NO and relaxation of pulmonary arteries were slightly decreased in pulmonary arteries from Kcnn4^−/− versus wt mice. An activator of TRPV4 channels, GSK1016790A, increased NO and relaxation to the same degree in pulmonary arteries from wt and Kcnn4^−/− mice. A blocker of TRPV4 channels, HC06704, inhibited increases in NO concentration with no effect on acetylcholine (ACh) relaxation in pulmonary arteries from wt mice, but blocked increases in NO concentration and relaxation in pulmonary arteries from Kcnn4^−/− mice and responses to GSK1016790A in pulmonary arteries from wt and Kcnn4^−/− mice. Concentration-dependent relaxations induced by an inhibitor of sarcoplasmic Ca-ATPase, cyclopiazonic acid, were blocked in the presence of an inhibitor of NO synthase and a blocker of KCa3.1 channels, TRAM-34, in pulmonary arteries from wt mice, but were unaltered in the presence of TRAM-34 in arteries from Kcnn4^−/− mice, or the presence of a blocker of TRPV4 channels. In small human pulmonary arteries, ACh and sodium nitroprusside (SNP) induced concentration-dependent relaxations, blocked by endothelial cell removal, in the presence of an inhibitor of NO synthase and the KCa3.1 channel blocker TRAM-34. GSK1016790A induced relaxation of human pulmonary arteries with endothelium, but failed to relax arteries without endothelium. The findings suggest that TRPV4 channels are involved in endothelium-dependent relaxation and likely regulate pulmonary vascular tone by modulating NO release. Full article