Genetic determinants of risk in pulmonary arterial hypertension: international genome-wide association studies and meta-analysis

Genetically Proxied Phosphodiesterase Type 5 (PDE5) Inhibition and Risk of Dementia: A Drug Target Mendelian Randomization Study

Phosphodiesterase-5 (PDE5) inhibitors have gained interest as a potential treatment for dementia. However, current evidence is limited to observational and pre-clinical studies. We conducted a drug-target Mendelian randomization (MR) analysis to investigate the on-target effects of pharmacological PDE5 inhibition on dementia subtypes and related phenotypes. We selected variants from around the PDE5A locus associated with diastolic and systolic blood pressure, as well as circulating PDE5A levels, to create three instruments for genetically proxied PDE5A inhibition. Using two-sample MR, we validated the instruments against erectile dysfunction and pulmonary arterial hypertension before assessing their associations with dementia subtypes, dementia-related proteins, and neuroimaging traits. After correcting for multiple comparisons, genetically proxied PDE5 inhibition, per one SD lower in diastolic blood pressure, was associated with higher odds of Alzheimer's disease (OR 1.09, 95% CI 1.07-1.11) and Lewy body dementia (OR 1.32, 95% CI 1.23-1.41), but a trend towards lower odds of vascular dementia across all instruments. Genetically proxied PDE5 inhibition was associated with both beneficial and adverse effects on brain MRI traits. This included lower volumes of white matter hyperintensities (SD change - 0.035, 95% CI - 0.025, - 0.045), indicating potential benefits, but also reduced volumes of other structures, including the thalamus, suggesting potential adverse effects. PDE5 inhibition was associated with the concentrations of several proteins implicated in dementia pathophysiology. Our findings suggest that while PDE5 inhibition may be associated with a lower risk of vascular dementia, possibly by preventing white matter hyperintensities, it may increase risk of Alzheimer's disease and Lewy body dementia, warranting further investigation before clinical trials.

Assessing causal relationships between gut microbiotas, metabolites, and pulmonary arterial hypertension through univariate Mendelian randomization study and bioinformatics analysis

BACKGROUND

Recent research has linked gut microbiotas and metabolites to the development and progression of pulmonary arterial hypertension (PAH) through the gut-lung axis. However, current studies on the causal relationship between gut microbiotas, gut microbiota derived metabolites, and PAH lack conclusive evidence. This study employed Mendelian randomization and bioinformatics analysis to reveal the possible causal links among them.

METHODS

Summary statistics of gut microbiotas, metabolites, and PAH were from GWAS. Univariate Mendelian randomization (inverse variance weighted and weighted median), reverse Mendelian randomization, and verification through other PAH GWAS cohorts were used to analyze the possible causal relationships between these gut microbiotas or gut microbiota derived metabolites and PAH. In addition, Cochran's Q statistic, MR-Egger regression intercept, MR-PRESSO global test, and the leave-one-out method were used for the sensitivity analysis. Based on this, we carried out an initial bioinformatics analysis to investigate its potential biological mechanisms.

RESULTS

Preliminary screening of the present research revealed four gut microbiotas ( Genus Eubacteriumfissicatenagroup , Genus RuminococcaceaeUCG002, Genus Tyzzerella3, and Genus Sutterella) and one metabolite (taurolithocholate 3-sulfate) correlated with PAH. However, after validation in other PAH GWAS cohorts, only genetically increased Genus Tyzzerella3 (odds ratio: 0.54, 95% confidence interval: 0.37-0.80, P  = 0.0018) correlated with a reduced risk for PAH, a relationship may be related to the keratan sulfate and glycosphingolipid synthesis. No significant heterogeneity, pleiotropy, or reversal causation effect was observed ( P  > 0.05).

CONCLUSION

Our Mendelian randomization analysis establishes a significant correlation between Genus Tyzzerella3 and PAH, positioning it as a prominent protective factor for PAH.

Therapeutic targets for pulmonary arterial hypertension: insights into the emerging landscape

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive, life-threatening disease driven by vascular remodeling, right ventricular (RV) dysfunction, and metabolic and inflammatory dysregulation. Current therapies primarily target vasodilation to relieve symptoms but do not reverse disease progression. The recent approval of sotatercept, which modulates BMP/TGF-β signaling, marks a shift toward anti-remodeling therapies. Building on this, recent preclinical advances have identified promising therapeutic targets and potentially disease-modifying treatments.

AREAS COVERED

This review synthesizes the evolving preclinical landscape of emerging PAH therapeutic targets and drugs, highlighting innovative approaches aimed at addressing the underlying mechanisms of disease progression. Additionally, we discuss novel therapeutic strategies under development.

EXPERT OPINION

Recent advances in PAH research have identified novel therapeutic targets beyond vasodilators, including modulation of BMP/TGF-β signaling, metabolic programs, epigenetics, cancer-related signaling, the extracellular matrix, and immune pathways, among others. Sotatercept represents a significant advance in therapies that go beyond vasodilation, and long-term safety, efficacy, and durability are being assessed. Future treatment strategies will focus on precision approaches, noninvasive technologies, and regenerative biology to improve outcomes and reverse vascular remodeling.

Association of Pulmonary Hypertension With Trastuzumab Emtansine: An Analysis of French Pulmonary Hypertension Registry and WHO Pharmacovigilance Database

BACKGROUND

Trastuzumab emtansine has been recently suspected to be associated with the development of pulmonary arterial hypertension (PAH).

RESEARCH QUESTION

Is there an association between trastuzumab, trastuzumab emtansine, or trastuzumab deruxtecan and the development of PAH?

STUDY DESIGN AND METHODS

Characteristics of incident PAH cases treated with trastuzumab, trastuzumab emtansine, or trastuzumab deruxtecan were analyzed from the French Pulmonary Hypertension Registry, the VIGIAPATH program, concurrently with a pharmacovigilance disproportionality analysis using the World Health Organization pharmacovigilance database using a broad definition of pulmonary hypertension (PH) and a narrow definition of PAH. A signal of disproportionate reporting was deemed significant if the lower boundary of the 95% credibility interval of the information component (IC) was superior to 0. The variables were expressed as median (interquartile range [IQR]).

RESULTS

In the French PH Registry, we identified 8 incident cases of PAH after trastuzumab emtansine exposure and none with trastuzumab alone or trastuzumab deruxtecan. All cases occurred in female patients (age, 56; IQR, 49-61 years) with breast cancer. The delay between first exposure and PAH diagnosis was 43 months (IQR, 4.5-55). At diagnosis, 5 were in New York Heart Association functional class III/IV with severe hemodynamic impairment (mean pulmonary artery pressure, 42 mm Hg; cardiac index, 2.51 L/min/m2; pulmonary vascular resistance, 9.7 Wood units). Disproportionality analysis showed that only trastuzumab emtansine demonstrated a significant signal of disproportionate reporting using both a broad definition of PH (IC, 1.46; 0.86-1.95) and a narrow definition of PAH (IC, 1.76; 0.83-2.46). Trastuzumab displayed a significant signal using only the broad definition of PH, whereas trastuzumab deruxtecan was not associated with any significant signals of disproportionate reporting.

INTERPRETATION

Our results suggest that more patients exposed to trastuzumab emtansine developed PH compared with trastuzumab alone. Further assessment of this safety signal and exploration of pathophysiologic mechanisms is needed.

The Role of Genetics in Congenital Heart Disease-Associated Pulmonary Arterial Hypertension

Pulmonary arterial hypertension associated with congenital heart disease (APAH-CHD) is a severely progressive condition with complex pathogenesis. The aim of this study was to evaluate the contribution of genetic variants to the development of PAH in patients with APAH-CHD. Fifteen children and twenty-seven adults diagnosed with APAH-CHD were enrolled. Targeted next-generation sequencing was performed on PAH-associated genes (ABCC8, ACVRL1, AQP1, ATP13A3, BMPR2, CAV1, GDF2, GGCX, EIF2AK4, ENG, KCNK3, KDR, KLK1, SMAD1, SMAD4, SMAD9, SOX17, TBX4, TET2). A total of 21 distinct variants across 11 different genes were detected in 17 of the 42 patients. (ABCC8 = 2, ACVRL1 = 1, ATP13A3 = 2, BMPR2 = 4, GGCX = 1, EIF2AK4 = 2, ENG = 1, KDR = 3, SMAD1 = 1, SMAD9 = 1, TET2 = 3). Five of the patients with the mutation were under the age of 18, and 12 patients were adults. The most common CHD in patients with detected variants was VSD. PAH-related genetic variants were not uncommon in APAH-CHD patients. Our study identified 12 novel variants that may help to understand the genetic basis of APAH-CHD. Trial Registration The study has been registered on ClinicalTrials.gov with the identification number NCT05550389.

SOX17 Prevents Endothelial-Mesenchymal Transition of Pulmonary Arterial Endothelial Cells in Pulmonary Hypertension through Mediating TGF-β/Smad2/3 Signaling

Endothelial-to-mesenchymal transition (EndMT) has been reported to contribute to pulmonary vascular remodeling in patients with pulmonary hypertension (PH). Our study demonstrates that SOX17, a member of the SOX (SRY-Box) transcription factor family, plays a role in regulating pulmonary arterial homeostasis through extracellular vesicles in an autocrine and paracrine manner. However, the role of SOX17 in mediating EndMT of pulmonary arterial endothelial cells (PAECs) and its intracellular mechanisms remain unclear. Here we present evidence showing that downregulation of SOX17 expression is accompanied by significant pulmonary arterial EndMT and activation of the TGF-β/Smad2/3 signaling pathway in patients with idiopathic PH and rats with PH induced by Sugen 5416/hypoxia. In primary human PAECs, canonical TGF-β (transforming growth factor-β) signaling inhibits the expression of SOX17. Overexpression of SOX17 reverses TGF-β- and hypoxia-induced EndMT. These findings suggest that SOX17 is essential for human PAECs to undergo TGF-β-mediated EndMT. Mechanistically, our data demonstrate that SOX17 prevents TGF-β-induced EndMT by suppressing ROCK1 (Rho-associated kinase 1) expression through binding to the specific promoter region of ROCK1, thereby inhibiting MYPT1 (myosin phosphatase target subunit 1) and MLC (myosin light chain) phosphorylation. Furthermore, we show that Tie2-Cre rats with endothelial cell-specific overexpression of SOX17 are protected against Sugen/hypoxia-induced EndMT and subsequent pulmonary vascular remodeling. Consistent with the in vitro results, compared with Tie2-Cre rats treated with Sugen/hypoxia alone, rats overexpressing SOX17 exhibited reduced levels of ROCK1 as well as decreased phosphorylation levels of MYPT1 and MLC. Overall, our studies unveil a novel TGF-β/SOX17/ROCK1 pathway involved in regulating PAECs' EndMT process, and we propose the targeting of SOX17 as a potential therapeutic strategy for alleviating pulmonary vascular remodeling in PH.

Spontaneous recovery from rocuronium measured by mechanomyography during 100- or 200-Hz tetanic stimulations compared to normalized train-of-four with acceleromyography

Neuromuscular block recovery was evaluated using high-frequency tetanic ulnar nerve simulations compared to normalized train-of-four (NTOF) in anesthetized patients. Under intravenous general anesthesia, we compared rocuronium-induced neuromuscular recovery using 5 s 100- and 200-Hz tetanic stimulations via isometric mechanomyography to acceleromyographic NTOF in 20 consenting patients. The primary outcome was the comparison by Student's t-tests of 100- and 200-Hz tetanic fade ratios (residual force at the end of the contraction / maximal force reached during the 5 s) before rocuronium administration and at different recovery levels. The secondary outcome was the quantification of any significant fade occurring with 100- and 200-Hz stimulations after reaching the acceleromyographic NTOF ratio of 0.9 during subsequent stages of spontaneous recovery until their fade ratios exceeded 0.9. During early (TOF count ≥ 1) and intermediate (NTOF ratio ≥ 0.5) stages of recovery, both 100- and 200-Hz tetanic fade ratios were similarly low. However, during late recovery when NTOF ratio ≥ 0.9, 200-Hz stimulation induced a significantly deeper muscular fade than 100-Hz (tetanic fade ratio 0.20 ± 0.23 vs. 0.64 ± 0.29, P < 0.001). The delays between the recovery of NTOF ratio 0.9 and 100- or 200-Hz tetanic fade ratio 0.9 were 7.7 ± 7.1 and 43.6 ± 14.6 min, respectively. In anesthetized humans, mechanomyographic 200-Hz tetanic stimulation detects lighter levels of residual paralysis than NTOF and 100-Hz tetanic stimulation during a valuable additional period. Registered in the ClinicalTrials.gov Registry NCT05474638 on July 15th 2022.

Pathogenic SMAD6 variants in patients with idiopathic and complex congenital heart disease associated pulmonary arterial hypertension

In patients with complex congenital heart disease (CHD) pathogenic SMAD6 variants have been described previously. The aim of this study was to analyze if pathogenic SMAD6 variants also occur in patients with CHD associated with pulmonary arterial hypertension (CHD-APAH) or idiopathic PAH. A PAH gene panel with up to 64 genes including SMAD6 was used to sequence 311 patients with idiopathic PAH (IPAH) and 32 with CHD-APAH. In 4 of 32 (12.5%) CHD-APAH and in 2 out of 311 (0.64%) IPAH patients we identified likely pathogenic or rare SMAD6 missense variants. All CHD-APAH patients with a rare SMAD6 variant had complex CHD. One patient had bi-allelic SMAD6 variants, combined pulmonary valve defect and supravalvular aortic stenosis, craniosynostosis and radioulnar synostosis. This is the first description of potentially disease-causing SMAD6 variants in patients with IPAH and complex CHD-APAH. Further studies are needed to assess pathogenesis and prevalence of pathogenic SMAD6 variants in PAH.

Exploring the Causal Relationship Between Gut Microbiota and Pulmonary Artery Hypertension: Insights From Mendelian Randomization

BACKGROUND

Research into the "gut-lung" axis links gut microbiota to pulmonary artery hypertension (PAH). However, the mechanisms by which gut microbiota influence PAH remain unclear. We aimed to investigate the causal relationship between the gut microbiota and PAH using Mendelian randomization analysis, identify key microbiota and metabolites, and explore the regulatory role of associated genes in PAH pathogenesis.

METHODS AND RESULTS

We examined the association between gut microbiota taxa and PAH using inverse variance weighted 2-sample Mendelian randomization analysis, Mendelian randomization-Egger, weighted median, and weighted mode methods. Additionally, we identified PAH-regulating genes in the intestinal microbiome using bioinformatics tools and validated their expression levels in the lung tissue of hypoxia-induced PAH mice models by quantitative reverse transcription polymerase chain reaction. Eleven gut microbiota taxa were associated with PAH. The order Clostridiales and genera Eubacterium fissicatena group, Lachnospiraceae UCG004, and Ruminococcaceae UCG002 were positively associated with PAH, whereas the order Bifidobacteriales; family Bifidobacteriaceae; and genera Eubacterium eligens group, Sutterella, Methanobrevibacter, Sellimonas, and Tyzzerella3 were negatively associated with PAH, with some exhibiting bidirectional causality. These microbiota modulate 24 metabolites, including palmitoylcholine, oleoylcholine, and 3,7-dimethylurate, to influence PAH. Hypoxia-induced PAH mice had significantly downregulated 1,4,5-trisphosphate receptor type 2, degrading enzyme, nuclear receptor-interacting protein 1, and growth factor-binding protein 1 in lung tissues, indicating their potential role in PAH regulation.

CONCLUSIONS

These findings suggest that gut microbiota composition and associated metabolites contribute to PAH development by regulating lung tissue gene expression. Our findings have implications for advancing gut microbiota-based PAH diagnostic technologies and targeted therapies.

SOX17-Associated Pulmonary Hypertension in Children: A Distinct Developmental and Clinical Syndrome

OBJECTIVE

To characterize clinical, hemodynamic, imaging, and pathologic findings in children with pulmonary arterial hypertension (PAH) and variants in SRY-box transcription factor 17 (SOX17), a novel risk gene linked to heritable and congenital heart disease-associated PAH.

STUDY DESIGN

We assembled a multi-institutional cohort of children with PAH and SOX17 variants enrolled in the Pediatric Pulmonary Hypertension Network (PPHNet) and other registries. Subjects were identified through exome and PAH gene panel sequencing. Data were collected from registries and retrospective chart review.

RESULTS

We identified 13 children (8 female, 5 male) aged 1.6-16 years at diagnosis with SOX17 variants and PAH. Seven patients had atrial septal defects and 2 had patent ductus arteriosus. At diagnostic cardiac catheterization, patients had severely elevated mean pulmonary artery (PA) pressure (mean 78, range 47-124 mmHg) and markedly elevated indexed pulmonary vascular resistance (mean 25.9, range 4.9-55 WU∗m2). No patients responded to acute vasodilator testing. Catheter and computed tomography angiography imaging demonstrated atypical PA anatomy including severely dilated main pulmonary arteries, lack of tapering in third and fourth order pulmonary arteries, tortuous 'corkscrewing' pulmonary arteries, and abnormal capillary 'blush.' Several children had PA stenoses and 2 had systemic arterial abnormalities. Histologic examination of explanted lungs from 3 patients disclosed plexiform arteriopathy and extensive aneurysmal dilation of alveolar septal capillaries.

CONCLUSIONS

SOX17-associated PAH is a distinctive genetic syndrome characterized by early onset severe PAH, extensive pulmonary vascular abnormalities, and high prevalence of congenital heart disease with intracardiac and interarterial shunts, suggesting a role for SOX17 in pulmonary vascular development.

2025 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2025 AHA Statistical Update is the product of a full year's worth of effort in 2024 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. This year's edition includes a continued focus on health equity across several key domains and enhanced global data that reflect improved methods and incorporation of ≈3000 new data sources since last year's Statistical Update.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Triangular Causality Among Pulmonary Hypertension, Sleep Disorders, and Brain Structure at the Genetic Level: A Mendelian Randomization Study Focused on the Lung-Brain Axis

Background

The bidirectional relationship between pulmonary hypertension (PH) and sleep disorders has attracted significant research attention. The concept of the lung-brain axis has further highlighted the need for a holistic approach to managing these diseases.

Methods

This study used bidirectional two-sample Mendelian Randomization (MR) to explore the genetic-level causal relationships between PH, sleep disorders, and structural brain changes. GWAS data for PH were pooled from four cohorts; data on four sleep disorder subtypes were sourced from the FinnGen database; and data on 15 structural brain changes were obtained from the ENIGMA Consortium. To ensure reliability, we applied strict data selection, multiple corrections, heterogeneity assessments, and sensitivity tests. Visualizations included forest plots, scatter plots, funnel plots, and leave-one-out plots.

Results

MR analysis revealed a significant causal relationship between PH and both obstructive sleep apnea (OSA) (OR = 1.022, 95% CI = 1.006-1.039, P = 0.006, PBonferroni = 0.025) and general sleep disorders (OR = 1.018, 95% CI = 1.003-1.033, P = 0.018, PFDR = 0.036), with no evidence of reverse causation and multivariable MR analyses also demonstrated significant results. PH was linked to changes in total brain volume (P = 0.032) and cerebral white matter (P = 0.035). Amygdala changes appeared to reduce the risk of sleep disorders (P = 0.008) and OSA (P = 0.014). Sensitivity analyses showed no heterogeneity, pleiotropy, or significant outliers.

Conclusion

This study identifies significant causal links between PH, sleep disorders, and structural brain changes, establishing a triangular cyclic relationship that supports the lung-brain axis concept. These findings inform clinical management of PH and its comorbidities.

Lipid-lowering drug targets associated with risk of respiratory disease: a Mendelian randomization study

BACKGROUND

Observational studies have identified a possible connection between lipid-lowering medications and respiratory illnesses. However, it remains unclear whether lipid-lowering drugs is causative for respiratory diseases, and we aimed to answer this question.

METHODS

We performed Mendelian randomization (MR) analyses by integrating data from genome-wide association studies (GWAS). Three statistical approaches were employed for MR analysis: inverse variance weighting (IVW), MR-Egger, and weighted median. The purpose was to evaluate the causal relationships between 10 drug targets that lower lipid levels and the likelihood of developing 7 respiratory diseases. Additional sensitivity analyses were conducted to ensure the robustness and validity of the results.

RESULTS

After adjusting for multiple testing, our MR analysis identified APOB (odd ratios [OR]: 0.86; 95% confidence interval [CI]: 0.77 to 0.97; PIVW = 0.01) and PCSK9 (OR: 0.84; 95% CI: 0.72 to 0.97; PIVW = 0.02) as significant risk targets for asthma. Additionally, LDLR was found to be a significant risk target for chronic obstructive pulmonary disease (OR: 0.81; 95% CI: 0.67 to 0.98; PIVW = 0.03). The sensitivity analysis validated no proof of heterogeneity or pleiotropy amongst the mentioned results.

CONCLUSIONS

Our findings suggest a likely causal relationship between respiratory diseases and lipid-lowering drug targets. Further mechanistic and clinical research is needed to confirm and validate these findings.

Mendelian randomization study of serum uric acid levels and urate-lowering drugs on pulmonary arterial hypertension outcomes

This study aims to explore the causal relationships between serum uric acid level and pulmonary arterial hypertension (PAH) using the Mendelian randomization (MR) approach, and to assess the therapeutic impacts of urate-lowering drugs on PAH. Utilizing published genome-wide association study (GWAS) data, we applied MR and colocalization analysis to assess the link between serum uric acid levesl and PAH across four GWAS datasets from two distinct European populations. The validity and reliability of these findings were confirmed through multiple statistical methods, along with an MR analysis of urate-lowering drug targets to investigate their potential effects on PAH treatment. MR analysis revealed a significant positive correlation between serum uric acid levels and PAH (odds ratio (OR) 1.106, 95% confidence intervals (CI) 1.021-1.200, P = 0.014), corroborated by a replication MR analysis (OR 1.859, 95% CI 1.130-3.057, P = 0.015). No significant heterogeneity or horizontal pleiotropy was found in the sensitivity analyses. However, urate-lowering drugs did not demonstrate a significant direct therapeutic effect on PAH. This study establishes a genetic basis for a causal link between serum uric acid levels and PAH. However, urate-lowering drugs do not appear to have a direct causal effect on improving PAH. These findings provide a novel reference point for developing future therapeutic strategies for PAH.

Mechanisms and treatment of pulmonary arterial hypertension

Substantial progress has been made in the management of pulmonary arterial hypertension (PAH) in the past 25 years, but the disease remains life-limiting. Established therapies for PAH are mostly limited to symptomatic relief by correcting the imbalance of vasoactive factors. The tyrosine kinase inhibitor imatinib, the first predominantly non-vasodilatory drug to be tested in patients with PAH, improved exercise capacity and pulmonary haemodynamics compared with placebo but at the expense of adverse events such as subdural haematoma. Given that administration by inhalation might reduce the risk of systemic adverse effects, inhaled formulations of tyrosine kinase inhibitors are currently in clinical development. Other novel therapeutic approaches for PAH include suppression of activin receptor type IIA signalling with sotatercept, which has shown substantial efficacy in clinical trials and was approved for use in the USA in 2024, but the long-term safety of the drug remains unclear. Future advances in the management of PAH will focus on right ventricular function and involve deep phenotyping and the development of a personalized medicine approach. In this Review, we summarize the mechanisms underlying PAH, provide an overview of available PAH therapies and their limitations, describe the development of newer, predominantly non-vasodilatory drugs that are currently being tested in phase II or III clinical trials, and discuss future directions for PAH research.

Genetic evidence for the causal effect of clonal hematopoiesis on pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is a severe and progressive cardiovascular disease. While potential links between clonal hematopoiesis (CH) and cardiovascular diseases have been identified, the causal relationship between CH and PAH remains unclear. This study aims to investigate the causal effect of CH on the risk of PAH using a two-sample Mendelian randomization (MR) approach.

METHODS

We utilized genetic variants associated with CH as instrumental variables, identified from two large genome-wide association studies (GWAS) involving 359,088 participants in the discovery cohort and 184,121 participants in the validation cohort, all of European descent. We obtained GWAS summary statistics for PAH. The inverse-variance weighted (IVW) method was employed as the primary analysis, complemented by sensitivity analyses to assess the robustness of our findings. A bidirectional MR analysis was conducted to estimate the causation between CH and PAH.

RESULTS

Our results indicate a causal effect of CH on the risk of PAH in the discovery cohort, with TET2 showing an IVW odds ratio (OR) of 1.200 (95% CI: 1.001-1.438, P = 0.049). Sensitivity analysis did not reveal significant pleiotropy or heterogeneity. In the validation cohort, we found that TET2 remains a risk factor for PAH (OR = 2.3E + 08, 95% CI 17.007-3.1E + 15, P = 0.022). Additionally, no causal relationship was found between other CH genes, such as DNMT3A and PAH (P > 0.05). The reverse MR analysis provided no evidence of causal effects of PAH on CH.

CONCLUSION

These findings showed that individuals with CH due to TET2 mutations may have a higher risk of developing PAH, suggesting that the CH patients may be tested for TET2 gene mutations.

Shear stress unveils patient-specific transcriptional signatures in PAH: Towards personalized molecular diagnostics

Rationale: Pulmonary arterial hypertension (PAH) is a life-threatening disorder characterized by increased pulmonary blood pressures and regional inhomogeneities in flows, with diagnostic and treatment challenges arising from diverse underlying pathogenic mechanisms. Conventional in vitro models often obscure the mechanistic nuances of PAH by failing to replicate the dynamic mechanical environment of the diseased lung, limiting the identification of specific molecular patterns. To address this, we employed an in vitro shear stress model simulating physiological or pathological conditions to explore the transcriptional heterogeneity of human pulmonary microvascular endothelial cells (hPMECs) from PAH patients and healthy controls within their respective biomechanical context. Methods & Results: hPMECs from PAH patients and controls were exposed to static, low shear stress (LSS), and high shear stress (HSS) conditions, followed by bulk RNA-sequencing. While increasing shear stress resulted in a greater number of differentially expressed genes, traditional grouped analysis showed minimal overall transcriptional differences. Further, pathway enrichment analysis indicated common shear-induced responses in both groups, suggesting that standard analysis methods may mask meaningful disease-specific changes. Crucially, detailed dimensionality reduction analyses revealed pronounced inter-patient variability among PAH donors in response to increasing shear stress, facilitating the identification of 398 genes driving this transcriptional heterogeneity. Unsupervised clustering of these high-variability genes enabled the sub-classification of patients based on their unique transcriptomic profiles, each linked to specific combinations of PAH associated pathogenic pathways such as mesenchymal transition, inflammation, metabolism, extracellular matrix remodeling, and cell cycle/DNA damage signaling. Importantly, re-analysis of published peripheral blood mononuclear cell (PBMC) omics data from PAH patients confirmed the clinical feasibility to utilize these high-variability genes as a non-invasive, accessible approach for molecular patient stratification. Conclusion: Our study uncovers patient-specific transcriptomic patterns in PAH, providing a novel molecular sub-classification strategy. These findings represent a significant step toward personalized molecular diagnostics in PAH and eventual therapeutic interventions for clinically well-defined PAH patients, with potential applications in clinically accessible cell populations such as PBMCs.

Precision Medicine for Pulmonary Vascular Disease: The Future Is Now (2023 Grover Conference Series)

Pulmonary vascular disease is not a single condition; rather it can accompany a variety of pathologies that impact the pulmonary vasculature. Applying precision medicine strategies to better phenotype, diagnose, monitor, and treat pulmonary vascular disease is increasingly possible with the growing accessibility of powerful clinical and research tools. Nevertheless, challenges exist in implementing these tools to optimal effect. The 2023 Grover Conference Series reviewed the research landscape to summarize the current state of the art and provide a better understanding of the application of precision medicine to managing pulmonary vascular disease. In particular, the following aspects were discussed: (1) Clinical phenotypes, (2) genetics, (3) epigenetics, (4) biomarker discovery, (5) application of precision biology to clinical trials, (6) the right ventricle (RV), and (7) integrating precision medicine to clinical care. The present review summarizes the content of these discussions and the prospects for the future.

Reversal of inflammatory reprogramming by vasodilator agents in pulmonary hypertension

Background

Pulmonary arterial hypertension (PAH) is a deadly disease without effective non-invasive diagnostic and prognostic testing. It remains unclear whether vasodilators reverse inflammatory activation, a part of PAH pathogenesis. Single-cell profiling of inflammatory cells in blood could clarify these PAH mechanisms.

Methods

We evaluated a University of Pittsburgh Medical Center cohort consisting of idiopathic PAH (iPAH) and systemic sclerosis-associated PAH (sscPAH) patients and non-PAH controls. We performed single-cell RNA sequencing of peripheral blood mononuclear cells (PBMCs) from controls (n=3) and from PAH patients (iPAH and sscPAH) naïve to treatment (n=4), PAH patients 3 months after phosphodiesterase-5 inhibitor (PDE5i) treatment (n=7) and PAH patients 3 months after PDE5i+macitentan treatment (n=6). We compared the transcriptomes of five PBMC subtypes from iPAH and sscPAH to observe their serial responses to treatments. Furthermore, we utilised network analysis to illuminate the altered connectivity of biological networks in this complex disease.

Results

We defined differential gene expression and perturbed network connectivity in PBMCs of PAH patients following treatment with PDE5i or PDE5i+macitentan. Importantly, we identified significant reversal of inflammatory transcripts and pathways in the combined PAH patient cohort after vasodilator therapy in every PBMC type assessed. The "glucagon signalling in metabolic regulation" pathway in monocytes was reversed after vasodilator therapy via two independent analysis modalities.

Conclusion

Via a systems-biology approach, we define inflammatory reprogramming in the blood of PAH patients and the anti-inflammatory activity of vasodilators. Such findings establish diagnostic and prognostic blood-based tools for tracking inflammatory progression of PAH and response to therapy.

Serum proteome profiling reveals HGFA as a candidate biomarker for pulmonary arterial hypertension

BACKGROUND

Identification and validation of potential biomarkers could facilitate the identification of pulmonary arterial hypertension (PAH) and thus aid to study their roles in the disease process.

METHODS

We used the isobaric tag for relative and absolute quantitation approaches to compare the protein profiles between the serum of PAH patients and the controls. Bioinformatics analyses and enzyme-linked immunosorbent assay (ELISA) identification of PAH patients and the controls were performed to identify the potential biomarkers. The receiver operating characteristic curve (ROC) analysis was used to evaluate the diagnostic performance of these potential biomarkers. Mendelian randomization (MR) analysis further clarified the relationship between the potential biomarkers and PAH. Additionally, the expression levels of the potential biomarkers were further validated in two PAH animal models (monocrotaline-PH and Sugen5416 plus hypoxia-PH) using ELISA and reverse transcription-quantitative PCR (RT-qPCR).

RESULTS

We identified significant changes in three proteins including heparanase (HPSE), gelsolin (GSN), and hepatocyte growth factor activator (HGFA) in PAH patients. The ROC analysis showed that the areas under the curve of HPSE, GSN, and HGFA in differentiating PAH patients from controls were 0.769, 0.777, and 0.964, respectively. HGFA was correlated with multiple parameters of right ventricular functions in PAH patients. Besides proteomic analysis, we also used MR method to demonstrate the causal link between genetically reduced HGFA levels and an increased risk of PAH. In subsequent validation study in PAH animal models, the mRNA expression levels of HGFA in the lung tissues were significantly lower in PAH rat models than in controls. In the rat models, serum levels of HGFA were lower compared to the control group and showed a negative correlation with right ventricular systolic pressure.

CONCLUSION

The study demonstrated that HGFA might be a promising biomarker for noninvasive detection of PAH.

Serum uric acid and pulmonary arterial hypertension: A two-sample Mendelian randomization study

BACKGROUND

Observational studies have suggested a correlation between hyperuricemia and pulmonary arterial hypertension (PAH), yet the causal relationship remains uncertain. We aimed to establish this link using Mendelian Randomization (MR) methods.

OBJECTIVES

Based on publicly accessible data, our study employs MR to determine the causal relationship between uric acid (UA) and PAH.

METHOD

MR analysis was conducted among individuals of European descent. Genetic instruments linked to UA (p-value < 5 × 10-8) were extracted from the Chronic Kidney Disease Genetic Consortium and genome-wide association study databases. PAH risk genetic associations were sourced separately. We employed four MR methods (MR-Egger, weighted median, inverse variance weighted, and weighted mode) with selected instrumental variables to assess the causal association between UA and PAH. MR-PRESSO was used to evaluate pleiotropy and outlier Single Nucleotide Polymorphisms (SNPs), while Cochran's Q test and funnel plot assessed SNP heterogeneity. Leave-one-out analysis examined SNP impacts on causal assessment.

RESULT

Two-sample MR analysis revealed a positive, causal relationship between UA levels and PAH.

CONCLUSION

Our MR analysis provides robust evidence of a causal link between serum UA and PAH, suggesting UA's potential as a biomarker and therapeutic target for PAH.

Exploring IRGs as a Biomarker of Pulmonary Hypertension Using Multiple Machine Learning Algorithms

BACKGROUND

Pulmonary arterial hypertension (PAH) is a severe disease with poor prognosis and high mortality, lacking simple and sensitive diagnostic biomarkers in clinical practice. This study aims to identify novel diagnostic biomarkers for PAH using genomics research.

METHODS

We conducted a comprehensive analysis of a large transcriptome dataset, including PAH and inflammatory response genes (IRGs), integrated with 113 machine learning models to assess diagnostic potential. We developed a clinical diagnostic model based on hub genes, evaluating their effectiveness through calibration curves, clinical decision curves, and ROC curves. An animal model of PAH was also established to validate hub gene expression patterns.

RESULTS

Among the 113 machine learning algorithms, the Lasso + LDA model achieved the highest AUC of 0.741. Differential expression profiles of hub genes CTGF, DDR2, FGFR2, MYH10, and YAP1 were observed between the PAH and normal control groups. A diagnostic model utilizing these hub genes was developed, showing high accuracy with an AUC of 0.87. MYH10 demonstrated the most favorable diagnostic performance with an AUC of 0.8. Animal experiments confirmed the differential expression of CTGF, DDR2, FGFR2, MYH10, and YAP1 between the PAH and control groups (p < 0.05); Conclusions: We successfully established a diagnostic model for PAH using IRGs, demonstrating excellent diagnostic performance. CTGF, DDR2, FGFR2, MYH10, and YAP1 may serve as novel molecular diagnostic markers for PAH.

Single-cell transcriptomics reveal diverging pathobiology and opportunities for precision targeting in scleroderma-associated versus idiopathic pulmonary arterial hypertension

Introduction

Pulmonary arterial hypertension (PAH) involves progressive cellular and molecular change within the pulmonary vasculature, leading to increased vascular resistance. Current therapies targeting nitric oxide (NO), endothelin, and prostacyclin pathways yield variable treatment responses. Patients with systemic sclerosis-associated PAH (SSc-PAH) often experience worse outcomes than those with idiopathic PAH (IPAH).

Methods

Lung tissue samples from four SSc-PAH, four IPAH, and four failed donor specimens were obtained from the Pulmonary Hypertension Breakthrough Initiative (PHBI) lung tissue bank. Single-cell RNA sequencing (scRNAseq) was performed using the 10X Genomics Chromium Flex platform. Data normalization, clustering, and differential expression analysis were conducted using Seurat. Additional analyses included gene set enrichment analysis (GSEA), transcription factor activity analysis, and ligand-receptor signaling. Pharmacotranscriptomic screening was performed using the Connectivity Map.

Results

SSc-PAH samples showed a higher proportion of fibroblasts and dendritic cells/macrophages compared to IPAH and donor samples. GSEA revealed enriched pathways related to epithelial-to-mesenchymal transition (EMT), apoptosis, and vascular remodeling in SSc-PAH samples. There was pronounced differential gene expression across diverse pulmonary vascular cell types and in various epithelial cell types in both IPAH and SSc-PAH, with epithelial to endothelial cell signaling observed. Macrophage to endothelial cell signaling was particularly pronounced in SSc-PAH. Pharmacotranscriptomic screening identified TIE2, GSK-3, and PKC inhibitors, among other compounds, as potential drug candidates for reversing SSc-PAH gene expression signatures.

Discussion

Overlapping and distinct gene expression patterns exist in SSc-PAH versus IPAH, with significant molecular differences suggesting unique pathogenic mechanisms in SSc-PAH. These findings highlight the potential for precision-targeted therapies to improve SSc-PAH patient outcomes. Future studies should validate these targets clinically and explore their therapeutic efficacy.

Integrative Multiomics in the Lung Reveals a Protective Role of Asporin in Pulmonary Arterial Hypertension

BACKGROUND

Integrative multiomics can elucidate pulmonary arterial hypertension (PAH) pathobiology, but procuring human PAH lung samples is rare.

METHODS

We leveraged transcriptomic profiling and deep phenotyping of the largest multicenter PAH lung biobank to date (96 disease and 52 control) by integration with clinicopathologic data, genome-wide association studies, Bayesian regulatory networks, single-cell transcriptomics, and pharmacotranscriptomics.

RESULTS

We identified 2 potentially protective gene network modules associated with vascular cells, and we validated ASPN, coding for asporin, as a key hub gene that is upregulated as a compensatory response to counteract PAH. We found that asporin is upregulated in lungs and plasma of multiple independent PAH cohorts and correlates with reduced PAH severity. We show that asporin inhibits proliferation and transforming growth factor-β/phosphorylated SMAD2/3 signaling in pulmonary artery smooth muscle cells from PAH lungs. We demonstrate in Sugen-hypoxia rats that ASPN knockdown exacerbated PAH and recombinant asporin attenuated PAH.

CONCLUSIONS

Our integrative systems biology approach to dissect the PAH lung transcriptome uncovered asporin as a novel protective target with therapeutic potential in PAH.

Sex-specific Genetic Determinants of Right Ventricular Structure and Function

RATIONALE

While sex differences in right heart phenotypes have been observed, the molecular drivers remain unknown.

OBJECTIVES

To provide biological insights into sex differences in the structure and function of the right ventricle (RV) using common genetic variation.

METHODS

RV phenotypes were obtained from cardiac magnetic resonance imaging in 18,156 women and 16,171 men from the UK Biobank. Observational analyses and sex-stratified genome-wide association studies were performed. Candidate female-specific loci were evaluated against invasively measured cardiac performance in 479 female patients with idiopathic or heritable pulmonary arterial hypertension (PAH), recruited to the UK NIHR BioResource Rare Diseases study.

MEASUREMENTS AND MAIN RESULTS

Sex was associated with differences in RV volumes and ejection fraction in models adjusting for left heart counterparts, blood pressure, lung function and sex hormone levels. Six genome-wide significant loci (13%) revealed heterogeneity of allelic effects between women and men, and significant sex-by-genotype interaction. These included two sex-specific candidate loci present in women only: a locus for RV ejection fraction in BMPR1A and a locus for RV end-systolic volume near DMRT2. Epigenetic data in RV tissue indicate that variation at the BMPR1A locus likely alters transcriptional regulation. In female patients with PAH, a variant located in the promoter of BMPR1A was significantly associated with cardiac index (effect size 0.16 l/min/m2), despite similar RV afterload.

CONCLUSIONS

BMPR1A has emerged as a biologically plausible candidate gene for female-specific genetic determination of RV function, showing associations with cardiac performance under chronically increased afterload in female patients with PAH.

Genome-wide assessment of shared genetic landscape of idiopathic pulmonary fibrosis and its comorbidities

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease accompanied by both local and systemic comorbidities. Genetic factors play a role in the development of IPF and certain associated comorbidities. Nevertheless, it is uncertain whether there are shared genetic factors underlying IPF and these comorbidities. To bridge this knowledge gap, we conducted a systematic investigation into the shared genetic architecture between IPF and ten prevalent heritable comorbidities (i.e., body mass index [BMI], coronary artery disease [CAD], chronic obstructive pulmonary disease [COPD], gastroesophageal reflux disease, lung cancer, major depressive disorder [MDD], obstructive sleep apnoea, pulmonary hypertension [PH], stroke, and type 2 diabetes), by utilizing large-scale summary data from their respective genome-wide association studies and multi-omics studies. We revealed significant (false discovery rate [FDR] < 0.05) and moderate genetic correlations between IPF and seven comorbidities, excluding lung cancer, MDD and PH. Evidence suggested a partially putative causal effect of IPF on CAD. Notably, we observed FDR-significant genetic enrichments in lung for the cross-trait between IPF and CAD and in liver for the cross-trait between IPF and COPD. Additionally, we identified 65 FDR-significant genes over-represented in 20 biological pathways related to the etiology of IPF, BMI, and COPD, including inflammation-related mucin gene clusters. Several of these genes were associated with clinically relevant drugs for the treatment of IPF, CAD, and/or COPD. Our results underscore the pervasive shared genetic basis between IPF and its common comorbidities and hold future implications for early diagnosis of IPF-related comorbidities, drug repurposing, and the development of novel therapies for IPF.

Pathology and pathobiology of pulmonary hypertension: current insights and future directions

In recent years, major advances have been made in the understanding of the cellular and molecular mechanisms driving pulmonary vascular remodelling in various forms of pulmonary hypertension, including pulmonary arterial hypertension, pulmonary hypertension associated with left heart disease, pulmonary hypertension associated with chronic lung disease and hypoxia, and chronic thromboembolic pulmonary hypertension. However, the survival rates for these different forms of pulmonary hypertension remain unsatisfactory, underscoring the crucial need to more effectively translate innovative scientific knowledge into healthcare interventions. In these proceedings of the 7th World Symposium on Pulmonary Hypertension, we delve into recent developments in the field of pathology and pathophysiology, prioritising them while questioning their relevance to different subsets of pulmonary hypertension. In addition, we explore how the latest omics and other technological advances can help us better and more rapidly understand the myriad basic mechanisms contributing to the initiation and progression of pulmonary vascular remodelling. Finally, we discuss strategies aimed at improving patient care, optimising drug development, and providing essential support to advance research in this field.

Genetics and precision genomics approaches to pulmonary hypertension

Considerable progress has been made in the genomics of pulmonary arterial hypertension (PAH) since the 6th World Symposium on Pulmonary Hypertension, with the identification of rare variants in several novel genes, as well as common variants that confer a modest increase in PAH risk. Gene and variant curation by an expert panel now provides a robust framework for knowing which genes to test and how to interpret variants in clinical practice. We recommend that genetic testing be offered to specific subgroups of symptomatic patients with PAH, and to children with certain types of group 3 pulmonary hypertension (PH). Testing of asymptomatic family members and the use of genetics in reproductive decision-making require the involvement of genetics experts. Large cohorts of PAH patients with biospecimens now exist and extension to non-group 1 PH has begun. However, these cohorts are largely of European origin; greater diversity will be essential to characterise the full extent of genomic variation contributing to PH risk and treatment responses. Other types of omics data are also being incorporated. Furthermore, to advance gene- and pathway-specific care and targeted therapies, gene-specific registries will be essential to support patients and their families and to lay the foundation for genetically informed clinical trials. This will require international outreach and collaboration between patients/families, clinicians and researchers. Ultimately, harmonisation of patient-derived biospecimens, clinical and omic information, and analytic approaches will advance the field.

Role of Forkhead box F1 in the Pathobiology of Pulmonary Arterial Hypertension

Rationale

Approximately 80% of patients with non-familial pulmonary arterial hypertension (PAH) lack identifiable pathogenic genetic variants. While most genetic studies of PAH have focused on predicted loss-of-function variants, recent approaches have identified ultra-rare missense variants associated with the disease. FOXF1 encodes a highly conserved transcription factor, essential for angiogenesis and vasculogenesis in human and mouse lungs.

Objectives

We identified a rare FOXF1 missense coding variant in two unrelated probands with PAH. FOXF1 is an evolutionarily conserved transcription factor required for lung vascular development and vascular integrity. Our aims were to determine the frequency of FOXF1 variants in larger PAH cohorts compared to the general population, study FOXF1 expression in explanted lung tissue from PAH patients versus control (failed-donor) lungs, and define potential downstream targets linked to PAH development.

Methods

Three independent, international, multicenter cohorts were analyzed to evaluate the frequency of FOXF1 rare variants. Various composite prediction models assessed the deleteriousness of individual variants. Bulk RNA sequencing datasets from human explanted lung tissues were compared to failed-donor controls to determine FOXF1 expression. Bioinformatic tools identified putative FOXF1 binding targets, which were orthogonally validated using mouse ChIP-seq datasets.

Measurements and Main Results

Seven novel or ultra-rare missense coding variants were identified across three patient cohorts in different regions of the FOXF1 gene, including the DNA binding domain. FOXF1 expression was dysregulated in PAH lungs, correlating with disease severity. Histological analysis showed heterogeneous FOXF1 expression, with the lowest levels in phenotypically abnormal endothelial cells within complex vascular lesions in PAH samples. A hybrid bioinformatic approach identified FOXF1 downstream targets potentially involved in PAH pathogenesis, including BMPR2 .

Conclusions

Large genomic and transcriptomic datasets suggest that decreased FOXF1 expression or predicted dysfunction is associated with PAH.

What can we learn from pathophysiology and therapeutic targetable pathways from all genetic causes and associations in PH?

Pulmonary hypertension (PH) encompasses a group of conditions which ultimately lead to elevated pulmonary arterial pressure. PH is classified into five subgroups, of which Group 1 pulmonary arterial hypertension (PAH), is the most extensively studied. Numerous causal genes have been identified in PAH, most notably germline mutations in bone morphogenetic protein receptor type 2 (BMPR2) and the wider BMP pathway. Often when considering the genetics of PH, sporadic idiopathic and heritable PAH dominates the discussion. There are a number of reviews that elegantly describe the 'state of the art' in respect to group 1 PAH, however this focus misses the wider context of genetic conditions where PH is a feature, but outside of the framework of classical 'idiopathic or heritable' PAH. In addition to variants in genes within the TGF-β/BMP signaling pathway, genes which regulate ion channels, the extracellular matrix, inflammation, angiogenesis, and mitochondrial dysfunction have been shown to play a significant role in PH pathogenesis across different PH groups. In this review, we aim to cast the net wider to understand what we can learn from the spectrum of genetic conditions where PH is an acknowledged feature or complication, and what this tells us about the important cellular, molecular and systems physiology features that predispose to PH and consequently might be treatment targets.

Genetics and Genomics of Pulmonary Fibrosis: Charting the Molecular Landscape and Shaping Precision Medicine

Recent genetic and genomic advancements have elucidated the complex etiology of idiopathic pulmonary fibrosis (IPF) and other progressive fibrotic interstitial lung diseases (ILDs), emphasizing the contribution of heritable factors. This state-of-the-art review synthesizes evidence on significant genetic contributors to pulmonary fibrosis (PF), including rare genetic variants and common SNPs. The MUC5B promoter variant is unusual, a common SNP that markedly elevates the risk of early and established PF. We address the utility of genetic variation in enhancing understanding of disease pathogenesis and clinical phenotypes, improving disease definitions, and informing prognosis and treatment response. Critical research gaps are highlighted, particularly the underrepresentation of non-European ancestries in PF genetic studies and the exploration of PF phenotypes beyond usual interstitial pneumonia/IPF. We discuss the role of telomere length, often critically short in PF, and its link to progression and mortality, underscoring the genetic complexity involving telomere biology genes (TERT, TERC) and others like SFTPC and MUC5B. In addition, we address the potential of gene-by-environment interactions to modulate disease manifestation, advocating for precision medicine in PF. Insights from gene expression profiling studies and multiomic analyses highlight the promise for understanding disease pathogenesis and offer new approaches to clinical care, therapeutic drug development, and biomarker discovery. Finally, we discuss the ethical, legal, and social implications of genomic research and therapies in PF, stressing the need for sound practices and informed clinical genetic discussions. Looking forward, we advocate for comprehensive genetic testing panels and polygenic risk scores to improve the management of PF and related ILDs across diverse populations.

Genetics of chronic respiratory disease

Chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD), asthma and interstitial lung diseases are frequently occurring disorders with a polygenic basis that account for a large global burden of morbidity and mortality. Recent large-scale genetic epidemiology studies have identified associations between genetic variation and individual respiratory diseases and linked specific genetic variants to quantitative traits related to lung function. These associations have improved our understanding of the genetic basis and mechanisms underlying common lung diseases. Moreover, examining the overlap between genetic associations of different respiratory conditions, along with evidence for gene-environment interactions, has yielded additional biological insights into affected molecular pathways. This genetic information could inform the assessment of respiratory disease risk and contribute to stratified treatment approaches.

Deficiency of the Deubiquitinase UCHL1 Attenuates Pulmonary Arterial Hypertension

BACKGROUND

The ubiquitin-proteasome system regulates protein degradation and the development of pulmonary arterial hypertension (PAH), but knowledge about the role of deubiquitinating enzymes in this process is limited. UCHL1 (ubiquitin carboxyl-terminal hydrolase 1), a deubiquitinase, has been shown to reduce AKT1 (AKT serine/threonine kinase 1) degradation, resulting in higher levels. Given that AKT1 is pathological in pulmonary hypertension, we hypothesized that UCHL1 deficiency attenuates PAH development by means of reductions in AKT1.

METHODS

Tissues from animal pulmonary hypertension models as well as human pulmonary artery endothelial cells from patients with PAH exhibited increased vascular UCHL1 staining and protein expression. Exposure to LDN57444, a UCHL1-specific inhibitor, reduced human pulmonary artery endothelial cell and smooth muscle cell proliferation. Across 3 preclinical PAH models, LDN57444-exposed animals, Uchl1 knockout rats (Uchl1-/-), and conditional Uchl1 knockout mice (Tie2Cre-Uchl1fl/fl) demonstrated reduced right ventricular hypertrophy, right ventricular systolic pressures, and obliterative vascular remodeling. Lungs and pulmonary artery endothelial cells isolated from Uchl1-/- animals exhibited reduced total and activated Akt with increased ubiquitinated Akt levels. UCHL1-silenced human pulmonary artery endothelial cells displayed reduced lysine(K)63-linked and increased K48-linked AKT1 levels.

RESULTS

Supporting experimental data, we found that rs9321, a variant in a GC-enriched region of the UCHL1 gene, is associated with reduced methylation (n=5133), increased UCHL1 gene expression in lungs (n=815), and reduced cardiac index in patients (n=796). In addition, Gadd45α (an established demethylating gene) knockout mice (Gadd45α-/-) exhibited reduced lung vascular UCHL1 and AKT1 expression along with attenuated hypoxic pulmonary hypertension.

CONCLUSIONS

Our findings suggest that UCHL1 deficiency results in PAH attenuation by means of reduced AKT1, highlighting a novel therapeutic pathway in PAH.

Shared and Distinct Genomics of Chronic Thromboembolic Pulmonary Hypertension and Pulmonary Embolism

Rationale: Chronic thromboembolic pulmonary hypertension involves the formation and nonresolution of thrombus, dysregulated inflammation, angiogenesis, and the development of a small-vessel vasculopathy. Objectives: We aimed to establish the genetic basis of chronic thromboembolic pulmonary hypertension to gain insight into its pathophysiological contributors. Methods: We conducted a genome-wide association study on 1,907 European cases and 10,363 European control subjects. We coanalyzed our results with existing results from genome-wide association studies on deep vein thrombosis, pulmonary embolism, and idiopathic pulmonary arterial hypertension. Measurements and Main Results: Our primary association study revealed genetic associations at the ABO, FGG, F11, MYH7B, and HLA-DRA loci. Through our coanalysis, we demonstrate further associations with chronic thromboembolic pulmonary hypertension at the F2, TSPAN15, SLC44A2, and F5 loci but find no statistically significant associations shared with idiopathic pulmonary arterial hypertension. Conclusions: Chronic thromboembolic pulmonary hypertension is a partially heritable polygenic disease, with related though distinct genetic associations with pulmonary embolism and deep vein thrombosis.

Otud6b induces pulmonary arterial hypertension by mediating the Calpain-1/HIF-1α signaling pathway

Pulmonary hypertension (PAH) is a cardiopulmonary disease in which pulmonary artery pressure continues to rise, leading to right heart failure and death. Otud6b is a member of the ubiquitin family and is involved in cell proliferation, apoptosis and inflammation. The aim of this study was to understand the role and mechanism of Otud6b in PAH. C57BL/6 and Calpain-1 knockout (KO) mice were exposed to a PAH model induced by 10% oxygen. Human pulmonary artery endothelial cells (HPACEs) and human pulmonary artery smooth muscle cells (HPASMCs) were exposed to 3% oxygen to establish an in vitro model. Proteomics was used to determine the role of Otud6b and its relationship to Calpain-1/HIF-1α signaling. The increased expression of Otud6b is associated with the progression of PAH. ROtud6b activates Otud6b, induces HIF-1α activation, increases the production of ET-1 and VEGF, and further aggravates endothelial injury. Reducing Otud6b expression by tracheal infusion of siOtud6b has the opposite effect, improving hemodynamic and cardiac response to PAH, reducing the release of Calpain-1 and HIF-1α, and eliminating the pro-inflammatory and apoptotic effects of Otud6b. At the same time, we also found that blocking Calpain-1 reduced the effect of Otud6b on HIF-1α, and inhibiting HIF-1α reduced the expression of Calpain-1 and Otud6b. Our study shows that increased Otud6b expression during hypoxia promotes the development of PAH models through a positive feedback loop between HIF-1α and Calpain-1. Therefore, we use Otud6b as a biomarker of PAH severity, and regulating Otud6b expression may be an effective target for the treatment of PAH.

Seeing pulmonary hypertension through a paediatric lens: a viewpoint

Pulmonary hypertension (PH) is a life-threating condition associated with abnormally elevated pulmonary pressures and right heart failure. Current epidemiological data indicate that PH aetiologies are different between the adult and paediatric population. The most common forms of PH in adults are PH from left heart disease or chronic lung disease, followed by pulmonary arterial hypertension (PAH) [1]; in paediatric patients, PH is most often associated with developmental lung disorders and congenital heart disease (CHD) [2, 3]. In contrast to adults with PH, wherein patients worsen over time despite therapy, PH in children can improve with growth. For example, in infants with bronchopulmonary dysplasia (BPD) and PH morbidity and mortality are high, but with lung growth and ensuring no ongoing lung injury pulmonary vascular disease can improve as evidenced by discontinuation of vasodilator therapy in almost two-thirds of BPD-PH survivors by age 5 years [3, 4].

Paediatric pulmonary hypertension (PH) offers unique genetic and developmental insights that can help in the discovery of novel mechanisms and targets to treat adult PH https://bit.ly/3TMm6bi

Genetically determined gut microbiota associates with pulmonary arterial hypertension: a Mendelian randomization study

BACKGROUND

Emerging evidences have demonstrated that gut microbiota composition is associated with pulmonary arterial hypertension (PAH). However, the underlying causality between intestinal dysbiosis and PAH remains unresolved.

METHOD

An analysis using the two-sample Mendelian randomization (MR) approach was conducted to examine the potential causal relationship between gut microbiota and PAH. To assess exposure data, genetic variants associated with 196 bacterial traits were extracted from the MiBioGen consortium, which included a sample size of 18,340 individuals. As for the outcomes, summary statistics for PAH were obtained from the NHGRI-EBI GWAS Catalog, which conducted a meta-analysis of four independent studies comprising a total of 11,744 samples. Causal effects were estimated employing various methods, including inverse variance weighted (IVW), MR-Egger, weighted median, weight mode and simple mode, with sensitivity analyses also being implemented with Cochran's Q test, MR-Egger intercept test, MR-PRESSO, leave-one-out analysis, and funnel plots.

RESULTS

Following false discovery rate (FDR) correction, the genetically predicted genus Eubacterium fissicatena group (odds ratio (OR) 1.471, 95% confidence interval (CI) 1.178-1.837, q = 0.076) exhibited a causal association with PAH. In addition, the genus LachnospiraceaeUCG004 (OR 1.511, 95% CI 1.048-2.177) and genus RuminococcaceaeUCG002 (OR 1.407, 95% CI 1.040-1.905) showed a suggestive increased risk of PAH, while genus Eubacterium eligens group (OR 0.563, 95% CI 0.344-0.922), genus Phascolarctobacterium (OR 0.692, 95% CI 0.487-0.982), genus Erysipelatoclostridium (OR 0.757, 95% CI 0.579-0.989) and genus T-yzzerella3 (OR 0.768, 95% CI 0.624-0.945) were found to have nominal protective effect against PAH.

CONCLUSION

The findings from our MR study have revealed a potential causal relationship between gut microbiota and PAH. Specifically, we have identified four types of gut microbiota that exhibit a protective effect on PAH, as well as three types that have a detrimental impact on PAH, thereby offering valuable insights for future mechanistic and clinical investigations in the field of PAH.

A time-resolved multi-omics atlas of transcriptional regulation in response to high-altitude hypoxia across whole-body tissues

High-altitude hypoxia acclimatization requires whole-body physiological regulation in highland immigrants, but the underlying genetic mechanism has not been clarified. Here we use sheep as an animal model for low-to-high altitude translocation. We generate multi-omics data including whole-genome sequences, time-resolved bulk RNA-Seq, ATAC-Seq and single-cell RNA-Seq from multiple tissues as well as phenotypic data from 20 bio-indicators. We characterize transcriptional changes of all genes in each tissue, and examine multi-tissue temporal dynamics and transcriptional interactions among genes. Particularly, we identify critical functional genes regulating the short response to hypoxia in each tissue (e.g., PARG in the cerebellum and HMOX1 in the colon). We further identify TAD-constrained cis-regulatory elements, which suppress the transcriptional activity of most genes under hypoxia. Phenotypic and transcriptional evidence indicate that antenatal hypoxia could improve hypoxia tolerance in offspring. Furthermore, we provide time-series expression data of candidate genes associated with human mountain sickness (e.g., BMPR2) and high-altitude adaptation (e.g., HIF1A). Our study provides valuable resources and insights for future hypoxia-related studies in mammals.

RNA modifications in pulmonary diseases

Threatening public health, pulmonary disease (PD) encompasses diverse lung injuries like chronic obstructive PD, pulmonary fibrosis, asthma, pulmonary infections due to pathogen invasion, and fatal lung cancer. The crucial involvement of RNA epigenetic modifications in PD pathogenesis is underscored by robust evidence. These modifications not only shape cell fates but also finely modulate the expression of genes linked to disease progression, suggesting their utility as biomarkers and targets for therapeutic strategies. The critical RNA modifications implicated in PDs are summarized in this review, including N6-methylation of adenosine, N1-methylation of adenosine, 5-methylcytosine, pseudouridine (5-ribosyl uracil), 7-methylguanosine, and adenosine to inosine editing, along with relevant regulatory mechanisms. By shedding light on the pathology of PDs, these summaries could spur the identification of new biomarkers and therapeutic strategies, ultimately paving the way for early PD diagnosis and treatment innovation.

[Research progress on bioinformatics in pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) is a severe disease characterized by abnormal pulmonary vascular remodeling and increased right ventricular pressure load, posing a significant threat to patient health. While some pathological mechanisms of PAH have been revealed, the deeper mechanisms of pathogenesis remain to be elucidated. In recent years, bioinformatics has provided a powerful tool for a deeper understanding of the complex mechanisms of PAH through the integration of techniques such as multi-omics analysis, artificial intelligence, and Mendelian randomization. This review focuses on the bioinformatics methods and technologies used in PAH research, summarizing their current applications in the study of disease mechanisms, diagnosis, and prognosis assessment. Additionally, it analyzes the existing challenges faced by bioinformatics and its potential applications in the clinical and basic research fields of PAH in the future.

Multi-biobank summary data Mendelian randomisation does not support a causal effect of IL-6 signalling on risk of pulmonary arterial hypertension

Interleukin (IL)-6 has been linked with the pathobiology of pulmonary arterial hypertension (PAH). IL-6 plasma levels are elevated in PAH patients and closely linked to survival [1]. Both increased IL-6 activity and gene knockout influence the development of, and resistance to, pulmonary hypertension in animal models [2–4]. IL-6 can repress expression of BMPR2, a gene key in PAH risk [5].

In the most comprehensive analysis to date, this study failed to detect an association of genetically predicted CRP-weighted IL-6 signalling or CRP-weighted IL-6R signalling with PAH risk using all available PAH GWAS data https://bit.ly/3T5h5uj

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

SOX on tumors, a comfort or a constraint?

The sex-determining region Y (SRY)-related high-mobility group (HMG) box (SOX) family, composed of 20 transcription factors, is a conserved family with a highly homologous HMG domain. Due to their crucial role in determining cell fate, the dysregulation of SOX family members is closely associated with tumorigenesis, including tumor invasion, metastasis, proliferation, apoptosis, epithelial-mesenchymal transition, stemness and drug resistance. Despite considerable research to investigate the mechanisms and functions of the SOX family, confusion remains regarding aspects such as the role of the SOX family in tumor immune microenvironment (TIME) and contradictory impacts the SOX family exerts on tumors. This review summarizes the physiological function of the SOX family and their multiple roles in tumors, with a focus on the relationship between the SOX family and TIME, aiming to propose their potential role in cancer and promising methods for treatment.

Pulmonary primary oxysterol and bile acid synthesis as a predictor of outcomes in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare and fatal vascular disease with heterogeneous clinical manifestations. To date, molecular determinants underlying the development of PAH and related outcomes remain poorly understood. Herein, we identify pulmonary primary oxysterol and bile acid synthesis (PPOBAS) as a previously unrecognized pathway central to PAH pathophysiology. Mass spectrometry analysis of 2,756 individuals across five independent studies revealed 51 distinct circulating metabolites that predicted PAH-related mortality and were enriched within the PPOBAS pathway. Across independent single-center PAH studies, PPOBAS pathway metabolites were also associated with multiple cardiopulmonary measures of PAH-specific pathophysiology. Furthermore, PPOBAS metabolites were found to be increased in human and rodent PAH lung tissue and specifically produced by pulmonary endothelial cells, consistent with pulmonary origin. Finally, a poly-metabolite risk score comprising 13 PPOBAS molecules was found to not only predict PAH-related mortality but also outperform current clinical risk scores. This work identifies PPOBAS as specifically altered within PAH and establishes needed prognostic biomarkers for guiding therapy in PAH.

Allele-specific control of rodent and human lncRNA KMT2E-AS1 promotes hypoxic endothelial pathology in pulmonary hypertension

Hypoxic reprogramming of vasculature relies on genetic, epigenetic, and metabolic circuitry, but the control points are unknown. In pulmonary arterial hypertension (PAH), a disease driven by hypoxia inducible factor (HIF)-dependent vascular dysfunction, HIF-2α promoted expression of neighboring genes, long noncoding RNA (lncRNA) histone lysine N-methyltransferase 2E-antisense 1 (KMT2E-AS1) and histone lysine N-methyltransferase 2E (KMT2E). KMT2E-AS1 stabilized KMT2E protein to increase epigenetic histone 3 lysine 4 trimethylation (H3K4me3), driving HIF-2α-dependent metabolic and pathogenic endothelial activity. This lncRNA axis also increased HIF-2α expression across epigenetic, transcriptional, and posttranscriptional contexts, thus promoting a positive feedback loop to further augment HIF-2α activity. We identified a genetic association between rs73184087, a single-nucleotide variant (SNV) within a KMT2E intron, and disease risk in PAH discovery and replication patient cohorts and in a global meta-analysis. This SNV displayed allele (G)-specific association with HIF-2α, engaged in long-range chromatin interactions, and induced the lncRNA-KMT2E tandem in hypoxic (G/G) cells. In vivo, KMT2E-AS1 deficiency protected against PAH in mice, as did pharmacologic inhibition of histone methylation in rats. Conversely, forced lncRNA expression promoted more severe PH. Thus, the KMT2E-AS1/KMT2E pair orchestrates across convergent multi-ome landscapes to mediate HIF-2α pathobiology and represents a key clinical target in pulmonary hypertension.

Unlocking the potential of genetic research in pulmonary arterial hypertension: Insights from clinicians, researchers, and study team

Genetic research and testing are increasingly important for understanding and treating pulmonary arterial hypertension. We aimed to explore how attitudes toward genetic research among clinical and research teams impacted the engagement in genetic research and the integration of genetic insights into clinical practice. We conducted 53 semistructured interviews and focus groups with patients, clinicians, and researchers from nine UK Pulmonary Hypertension centers, who had genetic research experience. Transcripts were thematically coded using inductive analysis. In this study, we focus on the researchers', clinicians', and study team's perspectives. From the interview data, several key themes emerged, ranging from study design, recruitment, and consent procedures to the return of individual genetic results. Additionally, participants reflected on both the successes of these studies and the future directions of genetic research. The analysis highlighted the critical importance of fostering collaborative networks firmly rooted in existing clinical and research infrastructure in rare disease study setups. Furthermore, the significance of trust-building, personalized communication, and transparency among stakeholders was underscored. The study offered valuable insights into the motivating and hindering factors to participant recruitment and consent procedures. Lastly, the findings gathered from processes surrounding the return of individual genetic results, genetic counselling, and the recruitment of relatives provided invaluable lessons regarding the integration of genetics into clinical practice. This in-depth analysis yields a crucial understanding of attitudes to genetic research among various stakeholders and sheds light on the complexities of genetic research and the evidence-practice gap.

Meta-analysis reveals differential gene expression in tetralogy of Fallot versus controls

OBJECTIVES

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect in the United States. We aimed to identify genetic variations associated with TOF using meta-analysis of publicly available digital samples to spotlight targets for prevention, screening, and treatment strategies.

METHODS

We used the Search Tag Analyze Resource for Gene Expression Omnibus (STARGEO) platform to identify 39 TOF and 19 non-TOF right ventricle tissue samples from microarray data and identified upregulated and downregulated genes. Associated gene expression data were analyzed using ingenuity pathway analysis and restricted to genes with a statistically significant (p < .05) difference and an absolute experimental log ratio >0.1 between disease and control samples.

RESULTS

Our analysis identified 220 genes whose expression profiles were significantly altered in TOF vs. non-TOF samples. The most striking differences identified in gene expression included genes FBXO32, PTGES, MYL12a, and NR2F2. Some top associated canonical pathways included adrenergic signaling, estrogen receptor signaling, and the role of NFAT in cardiac hypertrophy. In general, genes involved in adaptive, defensive, and reparative cardiovascular responses showed altered expression in TOF vs. non-TOF samples.

CONCLUSIONS

We introduced the interpretation of open "big data" using the STARGEO platform to define robust genomic signatures of congenital heart disease pathology of TOF. Overall, our meta-analysis results indicated increased metabolism, inflammation, and altered gene expression in TOF patients. Estrogen receptor signaling and the role of NFAT in cardiac hypertrophy represent unique pathways upregulated in TOF patients and are potential targets for future pharmacologic treatments.

Understanding what drives genetic study participation: Perspectives of patients, carers, and relatives

Genetic research's growing importance in understanding pulmonary arterial hypertension (PAH) and developing effective treatments prompted the RAPID-PAH study. This study sought feedback from stakeholders who participated in two genomic studies to enhance genetic study delivery and clinical integration. Stakeholders from nine UK PH centres, representing various roles, ages, genders, and mutation statuses, took part in 53 semi-structured interviews and focus groups. Transcripts were thematically coded using inductive analysis. Clustering analysis was conducted to identify patient groups that shared attitudes. In this paper, we focus on patients', carers', and relatives' perspectives. The key interview themes revealed insights into participants' attitudes toward genetic research and testing more generally, expertise and knowledge of the disease itself, motivations and barriers to participating in genetic research, awareness of and interest in consent procedures and the use of personal and genetic data, as well as the process of communicating individual genetic results. Factors influencing genetic research participation included altruistic motives, personal diagnostic experiences, and family-related hopes. Clustering analysis produced distinct clusters based on the presence of barriers and motivators for research participation; however, hardly any patients shared identical sets of attitudes, emphasising the need for personalised approaches to recruitment. Most patients reported poor engagement with study-related materials. Patients who received individual genetic results expressed satisfaction with the process, whereas those who did not were disappointed with the lack of feedback. Reflecting on patient perspectives, we offer recommendations to improve the genetic study delivery process. Enhancing genetic research integration into clinical practice requires tailored engagement, clear communication, and support from healthcare stakeholders.

Germline and Somatic Mutations in DNA Methyltransferase 3A (DNMT3A) Predispose to Pulmonary Arterial Hypertension (PAH) in Humans and Mice: Implications for Associated PAH

Background

Mutations are found in 10-20% of idiopathic PAH (IPAH) patients, but none are consistently identified in connective tissue disease-associated PAH (APAH), which accounts for ∼45% of PAH cases. TET2 mutations, a cause of clonal hematopoiesis of indeterminant potential (CHIP), predispose to an inflammatory type of PAH. We now examine mutations in another CHIP gene, DNMT3A , in PAH.

Methods

We assessed DNMT3A mutation prevalence in PAH Biobank subjects as compared with controls, first using whole exome sequencing (WES)-derived CHIP calls in 1832 PAH Biobank patients versus 7509 age-and sex-matched gnomAD controls. We then performed deep, targeted panel sequencing of CHIP genes on a subset of 710 PAH Biobank patients and compared the prevalence of DNMT3A mutations therein to an independent pooled control cohort (N = 3645). In another cohort of 80 PAH patients and 41 controls, DNMT3A mRNA expression was studied in peripheral blood mononuclear cells (PBMCs). Finally, we evaluated the development of PAH in a conditional, hematopoietic, Dnmt3a knockout mouse model.

Results

DNMT3A mutations were more frequent in PAH cases versus control subjects in the WES dataset (OR 2.60, 95% CI: 1.71-4.27). Among PAH patients, 33 had DNMT3A variants, most of whom had APAH (21/33). While 21/33 had somatic mutations (female:male 17:4), germline variants occurred in 12/33 (female:male 11:1). Hemodynamics were comparable with and without DNMT3A mutations (mPAP=58±21 vs. 52±18 mmHg); however, patients with DNMT3A mutations were unresponsive to acute vasodilator testing. Targeted panel sequencing identified that 14.6% of PAH patients had CHIP mutations (104/710), with DNMT3A accounting for 49/104. There was a significant association between all CHIP mutations and PAH in analyses adjusted for age and sex (OR 1.40, 95% CI: 1.09-1.80), though DNMT3A CHIP alone was not significantly enriched (OR:1.15, 0.82-1.61). DNMT3A expression was reduced in patient-derived versus control PAH-PBMCs. Spontaneous PAH developed in Dnmt3a -/- mice, and it was exacerbated by 3 weeks of hypoxia. Dnmt3a -/- mice had increased lung macrophages and elevated plasma IL-13. The IL-1β antibody canakinumab attenuated PAH in Dnmt3a -/- mice.

Conclusions

Germline and acquired DNMT3A variants predispose to PAH in humans. DNMT3A mRNA expression is reduced in human PAH PBMCs. Hematopoietic depletion of Dnmt3a causes inflammatory PAH in mice. DNMT3A is a novel APAH gene and may be a biomarker and therapeutic target.