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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-ß/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.
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Hereditary Hemorrhagic Telangiectasia (HHT) is a rare, autosomal dominant, vascular disorder. About 80% of cases are caused by pathogenic variants in ACVRL1 (also known as ALK1) and ENG, with the remaining cases being unexplained. We identified two variants, c.-79C>T and c.-68G>A, in the 5'UTR of ENG in two unrelated patients. They create upstream AUGs at the origin of upstream overlapping open reading frames (uoORFs) ending at the same stop codon. To assess the pathogenicity of these variants, we performed functional assays based on the expression of wild-type and mutant constructs in human cells and evaluated their effect on ALK1 activity in a BMP-response element assay. This assay is mandatory for molecular diagnosis and has been so far only applied to coding ENG variants. These variants were associated with a decrease of protein levels in HeLa and HUVEC cells and a decreased ability to activate ALK1. We applied the same experiments on three additional uoORF-creating variants (c.-142A>T, c.-127C>T and c.-10C>T) located in the 5'UTR of ENG and previously reported in HHT patients. We found that all the analyzed variants alter protein levels and function. Additional experiments relying on an artificial deletion in our mutated constructs show that identified uAUGs could initiate the translation indicating that the associated effect is translation-dependent. Overall, we have identified two 5'UTR ENG variations in HHT patients and shed new light on the role of upstream ORFs on ENG regulation. Our findings contribute to the amelioration of molecular diagnosis in HHT.
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Hereditary pulmonary veno-occlusive disease (hPVOD) is a severe form of autosomal recessive pulmonary hypertension and is due to biallelic loss of function of the EIF2AK4 gene (alias GCN2) coding for GCN2. GCN2 is a stress kinase that belongs to the integrated stress response pathway (ISR). Three rat lines carrying biallelic Gcn2 mutation were generated and found phenotypically normal and did not spontaneously develop a PVOD-related disease. We submitted these rats to amino acid deprivation to document the molecular and cellular response of the lungs and to identify phenotypic changes that could be involved in PVOD pathophysiology. Gcn2-/- rat lungs were analyzed under basal conditions and 3 days after a single administration of PEG-asparaginase (ASNase). Lung mRNAs were analyzed by RNAseq and single-cell RNAseq (scRNA-seq), flow cytometry, tissue imaging, and Western blots. The ISR was not activated after ASNase treatment in Gcn2-/- rat lungs, and apoptosis was increased. Several proinflammatory and innate immunity genes were overexpressed, and inflammatory cells infiltration was also observed in the perivascular area. Under basal conditions, scRNA-seq analysis of Gcn2-/- rat lungs revealed increases in two T-cell populations, a LAG3+ T-cell population and a proliferative T-cell population. Following ASNase administration, we observed an increase in calprotectin expression involved in TLR pathway activation and neutrophil infiltration. In conclusion, under basal and asparagine and glutamine deprivation induced by asparaginase administration, Gcn2-/- rats display molecular and cellular signatures in the lungs that may indicate a role for Gcn2 in immune homeostasis and provide further clues to the mechanisms of hPVOD development.
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Hipertensión Pulmonar , Enfermedad Veno-Oclusiva Pulmonar , Animales , Ratas , Pulmón/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Enfermedad Veno-Oclusiva Pulmonar/genética , ARN MensajeroRESUMEN
Pulmonary fibrosis (PF) and pulmonary hypertension (PH) are chronic diseases of the pulmonary parenchyma and circulation, respectively, which may coexist, but underlying mechanisms remain elusive. Mutations in the GCN2 (general control nonderepressible 2) gene (EIF2AK4 [eukaryotic translation initiation factor 2 alpha kinase 4]) were recently associated with pulmonary veno-occlusive disease. The aim of this study is to explore the involvement of the GCN2/eIF2α (eukaryotic initiation factor 2α) pathway in the development of PH during PF, in both human disease and in a laboratory animal model. Lung tissue from patients with PF with or without PH was collected at the time of lung transplantation, and control tissue was obtained from tumor resection surgery. Experimental lung disease was induced in either male wild-type or EIF2AK4-mutated Sprague-Dawley rats, randomly receiving a single intratracheal instillation of bleomycin or saline. Hemodynamic studies and organ collection were performed 3 weeks after instillation. Only significant results (P < 0.05) are presented. In PF lung tissue, GCN2 protein expression was decreased compared with control tissue. GCN2 expression was reduced in CD31+ endothelial cells. In line with human data, GCN2 protein expression was decreased in the lung of bleomycin rats compared with saline. EIF2AK4-mutated rats treated with bleomycin showed increased parenchymal fibrosis (hydroxyproline concentrations) and vascular remodeling (media wall thickness) as well as increased right ventricular systolic pressure compared with wild-type animals. Our data show that GCN2 is dysregulated in both humans and in an animal model of combined PF and PH. The possibility of a causative implication of GCN2 dysregulation in PF and/or PH development should be further studied.
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Hipertensión Pulmonar , Fibrosis Pulmonar , Animales , Humanos , Masculino , Ratas , Bleomicina , Células Endoteliales/patología , Hipertensión Pulmonar/patología , Pulmón/patología , Proteínas Serina-Treonina Quinasas/metabolismo , Fibrosis Pulmonar/patología , Ratas Sprague-DawleyRESUMEN
Pulmonary arterial hypertension (PAH) is a rare disease that can be caused by (likely) pathogenic germline genomic variants. In addition to the most prevalent disease gene, BMPR2 (bone morphogenetic protein receptor 2), several genes, some belonging to distinct functional classes, are also now known to predispose to the development of PAH. As a consequence, specialist and non-specialist clinicians and healthcare professionals are increasingly faced with a range of questions regarding the need for, approaches to and benefits/risks of genetic testing for PAH patients and/or related family members. We provide a consensus-based approach to recommendations for genetic counselling and assessment of current best practice for disease gene testing. We provide a framework and the type of information to be provided to patients and relatives through the process of genetic counselling, and describe the presently known disease causal genes to be analysed. Benefits of including molecular genetic testing within the management protocol of patients with PAH include the identification of individuals misclassified by other diagnostic approaches, the optimisation of phenotypic characterisation for aggregation of outcome data, including in clinical trials, and importantly through cascade screening, the detection of healthy causal variant carriers, to whom regular assessment should be offered.
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Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Humanos , Hipertensión Arterial Pulmonar/genética , Asesoramiento Genético/métodos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/genética , Mutación , Hipertensión Pulmonar Primaria Familiar/genética , Pruebas Genéticas , Receptores de Proteínas Morfogenéticas Óseas de Tipo II/genética , Predisposición Genética a la EnfermedadRESUMEN
Objective: To study the genotypes and phenotypes of cerebral arteriovenous fistulas that drain or do not drain through the vein of Galen, and true vein of Galen aneurysmal malformations, in order to determine whether genotyping could help improve classification of these malformations and their management. Methods: We carried out a retrospective review of genetic and phenotypic data in databases of four centers. All children with cerebral arteriovenous fistula or vein of Galen aneurysmal malformations aged below 18 years at onset were included. We recorded the nature of the genetic variant or absence of variant, age at onset, type of malformation, symptoms at onset (hemorrhage, neurological deficit, hydrocephalus, incidental, and heart failure), type of venous drainage and the long-term outcome. Results: One hundred and fifteen children were included. Autosomal dominant variants were identified in 39% of patients. The most frequent variant affected was the RASA1 gene (25%) followed by EPHB4 (8%) and the HHT-associated genes (5%). HHT gene variants were only observed in pial arteriovenous fistula not draining into the vein of Galen; on the contrary, EPHB4 variants were only seen in genuine vein of Galen aneurysmal malformation. RASA1 variants were identified in all types of shunts. Conclusions: EPHB4 variants seem specific to the vein of Galen aneurysmal malformation, RASA1 variants are associated with either pial arteriovenous fistulas or with genuine VGAM and HHT gene variants seem specific to pial arteriovenous fistulas. The genetic data helps to classify these malformations and to guide treatment toward lowest risk of post-operative cerebral ischemic-hemorrhagic complications.
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The lack of curative options for pulmonary arterial hypertension drives important research to understand the mechanisms underlying this devastating disease. Among the main identified pathways, the platelet-derived growth factor (PDGF) pathway was established to control vascular remodeling and anti-PDGF receptor (PDGFR) drugs were shown to reverse the disease in experimental models. Four different isoforms of PDGF are produced by various cell types in the lung. PDGFs control vascular cells migration, proliferation and survival through binding to their receptors PDGFRα and ß. They elicit multiple intracellular signaling pathways which have been particularly studied in pulmonary smooth muscle cells. Activation of the PDGF pathway has been demonstrated both in patients and in pulmonary hypertension (PH) experimental models. Tyrosine kinase inhibitors (TKI) are numerous but without real specificity and Imatinib, one of the most specific, resulted in beneficial effects. However, adverse events and treatment discontinuation discouraged to pursue this therapy. Novel therapeutic strategies are currently under experimental evaluation. For TKI, they include intratracheal drug administration, low dosage or nanoparticles delivery. Specific anti-PDGF and anti-PDGFR molecules can also be designed such as new TKI, soluble receptors, aptamers or oligonucleotides.
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BACKGROUND: The phenotype of pulmonary arterial hypertension (PAH) patients carrying SOX17 pathogenic variants remains mostly unknown. METHODS: We report the genetic analysis findings, characteristics and outcomes of patients with heritable PAH carrying SOX17 variants from the French Pulmonary Hypertension Network. RESULTS: 20 patients and eight unaffected relatives were identified. The median (range) age at diagnosis was 17 (2-53)â years, with a female:male ratio of 1.5. At diagnosis, most of the patients (74%) were in New York Heart Association Functional Class III or IV with severe haemodynamic compromise, including a median pulmonary vascular resistance of 14.0 (4.2-31.5)â WU. An associated congenital heart disease (CHD) was found in seven PAH patients (35%). Patients with CHD-associated PAH were significantly younger at diagnosis than PAH patients without CHD. Four patients (20%) suffered from recurrent haemoptysis requiring repeated arterial embolisations. 13 out of 16 patients (81%) for whom imaging was available displayed chest computed tomography abnormalities, including dilated, tortuous pulmonary vessels, ground-glass opacities as well as anomalies of the bronchial and nonbronchial arteries. After a median (range) follow-up of 47 (1-591)â months, 10 patients underwent lung transplantation and one patient benefited from a heart-lung transplantation due to associated CHD. Histopathological analysis of lung explants showed a congested lung architecture with severe pulmonary arterial remodelling, subpleural vessel dilation and numerous haemorrhagic foci. CONCLUSIONS: PAH due to SOX17 pathogenic variants is a severe phenotype, frequently associated with CHD, haemoptysis and radiological abnormalities. Pathological assessment reveals severe pulmonary arterial remodelling and malformations affecting pulmonary vessels and thoracic systemic arteries.
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Cardiopatías Congénitas , Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Masculino , Femenino , Humanos , Hipertensión Arterial Pulmonar/genética , Hipertensión Arterial Pulmonar/complicaciones , Hemoptisis , Remodelación Vascular/genética , Hipertensión Pulmonar Primaria Familiar/genética , Cardiopatías Congénitas/complicaciones , Fenotipo , Factores de Transcripción SOXF/genéticaRESUMEN
Background Platelet-derived growth factor is a major regulator of the vascular remodeling associated with pulmonary arterial hypertension. We previously showed that protein widely 1 (PW1+) vascular progenitor cells participate in early vessel neomuscularization during experimental pulmonary hypertension (PH) and we addressed the role of the platelet-derived growth factor receptor type α (PDGFRα) pathway in progenitor cell-dependent vascular remodeling and in PH development. Methods and Results Remodeled pulmonary arteries from patients with idiopathic pulmonary arterial hypertension showed an increased number of perivascular and vascular PW1+ cells expressing PDGFRα. PW1nLacZ reporter mice were used to follow the fate of pulmonary PW1+ progenitor cells in a model of chronic hypoxia-induced PH development. Under chronic hypoxia, PDGFRα inhibition prevented the increase in PW1+ progenitor cell proliferation and differentiation into vascular smooth muscle cells and reduced pulmonary vessel neomuscularization, but did not prevent an increased right ventricular systolic pressure or the development of right ventricular hypertrophy. Conversely, constitutive PDGFRα activation led to neomuscularization via PW1+ progenitor cell differentiation into new smooth muscle cells and to PH development in male mice without fibrosis. In vitro, PW1+ progenitor cell proliferation, but not differentiation, was dependent on PDGFRα activity. Conclusions These results demonstrate a major role of PDGFRα signaling in progenitor cell-dependent lung vessel neomuscularization and vascular remodeling contributing to PH development, including in idiopathic pulmonary arterial hypertension patients. Our findings suggest that PDGFRα blockers may offer a therapeutic add-on strategy to combine with current pulmonary arterial hypertension treatments to reduce vascular remodeling. Furthermore, our study highlights constitutive PDGFRα activation as a novel experimental PH model.
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Hipertensión Pulmonar , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas , Animales , Proliferación Celular , Células Cultivadas , Humanos , Hipertensión Pulmonar/metabolismo , Hipoxia , Pulmón , Masculino , Ratones , Músculo Liso Vascular/metabolismo , Miocitos del Músculo Liso/metabolismo , Arteria Pulmonar , Receptor alfa de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Remodelación VascularRESUMEN
BACKGROUND: Inflammation and dysregulated immunity are important in the development of pulmonary arterial hypertension (PAH). Compelling preclinical data supports the therapeutic blockade of interleukin-6 (IL-6) signalling. METHODS: We conducted a phase 2 open-label study of intravenous tocilizumab (8â mg·kg-1) over 6â months in patients with group 1 PAH. Co-primary end-points were safety, defined by incidence and severity of adverse events, and change in pulmonary vascular resistance. Separately, a mendelian randomisation study was undertaken on 11â744 individuals with European ancestry including 2085 patients with idiopathic/heritable disease for the IL-6 receptor (IL6R) variant (rs7529229), known to associate with circulating IL-6R levels. RESULTS: We recruited 29 patients (male/female 10/19; mean±sd age 54.9±11.4â years). Of these, 19 had heritable/idiopathic PAH and 10 had connective tissue disease-associated PAH. Six were withdrawn prior to drug administration; 23 patients received at least one dose of tocilizumab. Tocilizumab was discontinued in four patients owing to serious adverse events. There were no deaths. Despite evidence of target engagement in plasma IL-6 and C-reactive protein levels, both intention-to-treat and modified intention-to-treat analyses demonstrated no change in pulmonary vascular resistance. Inflammatory markers did not predict treatment response. Mendelian randomisation did not support an effect of the lead IL6R variant on risk of PAH (OR 0.99, p=0.88). CONCLUSION: Adverse events were consistent with the known safety profile of tocilizumab. Tocilizumab did not show any consistent treatment effect.
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Investigación Biomédica , Hipertensión Arterial Pulmonar , Adulto , Anciano , Hipertensión Pulmonar Primaria Familiar , Femenino , Humanos , Interleucina-6 , Masculino , Persona de Mediana Edad , Resultado del TratamientoAsunto(s)
Cadherinas/genética , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Mutación , Hipertensión Arterial Pulmonar/diagnóstico , Hipertensión Arterial Pulmonar/genética , Biomarcadores , Niño , Femenino , Estudios de Asociación Genética/métodos , Humanos , Fenotipo , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Diagnostic ionizing radiation is a risk factor for breast cancer (BC). BC risk increases with increased dose to the chest and decreases with increased age at exposure, with possible effect modification related to familial or genetic predisposition. While chest X-rays increase the BC risk of BRCA1/2 mutation carriers compared to non-carriers, little is known for women with a hereditary predisposition to BC but who tested negative for a BRCA1 or BRCA2 (BRCA1/2) mutation. METHODS: We evaluated the effect of chest X-rays from diagnostic medical procedures in a dataset composed of 1552 BC cases identified through French family cancer clinics and 1363 unrelated controls. Participants reported their history of X-ray exposures in a detailed questionnaire and were tested for 113 DNA repair genes. Logistic regression and multinomial logistic regression models were used to assess the association with BC. RESULTS: Chest X-ray exposure doubled BC risk. A 3% increased BC risk per additional exposure was observed. Being 20 years old or younger at first exposure or being exposed before first full-term pregnancy did not seem to modify this risk. Birth after 1960 or carrying a rare likely deleterious coding variant in a DNA repair gene other than BRCA1/2 modified the effect of chest X-ray exposure. CONCLUSION: Ever/never chest X-ray exposure increases BC risk 2-fold regardless of age at first exposure and, by up to 5-fold when carrying 3 or more rare variants in a DNA repair gene. Further studies are needed to evaluate other DNA repair genes or variants to identify those which could modify radiation sensitivity. Identification of subpopulations that are more or less susceptible to ionizing radiation is important and potentially clinically relevant.
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Neoplasias de la Mama/etiología , Predisposición Genética a la Enfermedad/genética , Radiografía/efectos adversos , Adulto , Neoplasias de la Mama/genética , Reparación del ADN/genética , Femenino , Genes BRCA1 , Genes BRCA2 , Humanos , Persona de Mediana Edad , Mutación , Radiografía/estadística & datos numéricos , Riesgo , Factores de Riesgo , Adulto JovenRESUMEN
Pulmonary arterial hypertension (PAH) is characterized by an important occlusive vascular remodeling with the production of new endothelial cells, smooth muscle cells, myofibroblasts, and fibroblasts. Identifying the cellular processes leading to vascular proliferation and dysfunction is a major goal in order to decipher the mechanisms leading to PAH development. In addition to in situ proliferation of vascular cells, studies from the past 20 years have unveiled the role of circulating and resident vascular in pulmonary vascular remodeling. This review aims at summarizing the current knowledge on the different progenitor and stem cells that have been shown to participate in pulmonary vascular lesions and on the pathways regulating their recruitment during PAH. Finally, this review also addresses the therapeutic potential of circulating endothelial progenitor cells and mesenchymal stem cells.
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Hipertensión Arterial Pulmonar/patología , Células Madre , Remodelación Vascular , Animales , Células Cultivadas , Humanos , Células Madre/citología , Células Madre/patologíaRESUMEN
Rationale: The cellular and molecular landscape and translational value of commonly used models of pulmonary arterial hypertension (PAH) are poorly understood. Single-cell transcriptomics can enhance molecular understanding of preclinical models and facilitate their rational use and interpretation.Objectives: To determine and prioritize dysregulated genes, pathways, and cell types in lungs of PAH rat models to assess relevance to human PAH and identify drug repositioning candidates.Methods: Single-cell RNA sequencing was performed on the lungs of monocrotaline (MCT), Sugen-hypoxia (SuHx), and control rats to identify altered genes and cell types, followed by validation using flow-sorted cells, RNA in situ hybridization, and immunofluorescence. Relevance to human PAH was assessed by histology of lungs from patients and via integration with human PAH genetic loci and known disease genes. Candidate drugs were predicted using Connectivity Map.Measurements and Main Results: Distinct changes in genes and pathways in numerous cell types were identified in SuHx and MCT lungs. Widespread upregulation of NF-κB signaling and downregulation of IFN signaling was observed across cell types. SuHx nonclassical monocytes and MCT conventional dendritic cells showed particularly strong NF-κB pathway activation. Genes altered in SuHx nonclassical monocytes were significantly enriched for PAH-associated genes and genetic variants, and candidate drugs predicted to reverse the changes were identified. An open-access online platform was developed to share single-cell data and drug candidates (http://mergeomics.research.idre.ucla.edu/PVDSingleCell/).Conclusions: Our study revealed the distinct and shared dysregulation of genes and pathways in two commonly used PAH models for the first time at single-cell resolution and demonstrated their relevance to human PAH and utility for drug repositioning.
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Antihipertensivos/uso terapéutico , Células Cultivadas/efectos de los fármacos , Reposicionamiento de Medicamentos , Regulación de la Expresión Génica/efectos de los fármacos , Hipertensión Arterial Pulmonar/tratamiento farmacológico , Hipertensión Arterial Pulmonar/genética , Hipertensión Arterial Pulmonar/fisiopatología , Animales , Modelos Animales de Enfermedad , Humanos , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
Background We report two cases of RASA1-related capillary malformation-arteriovenous malformation (CM-AVM1) syndrome mimicking hereditary haemorrhagic telangiectasia (HHT).Methods and results A 28-year-old man, previously embolised for cerebral arteriovenous malformations (AVMs), presented with epistaxis and typical nasal telangiectasias of HHT. CT scan revealed a large portocaval shunt. The second patient was a 9-year-old girl presenting with cyanosis and several mucocutaneous telangiectasias, similar to those observed in typical cases of HHT. CT scan revealed a huge and complex pulmonary AVM of the right lower lobe and a hepatic AVM within the left lobe. HHT diagnosis was considered possible according to the Curaçao criteria for the two patients, with at least two criteria for each. Genetic tests did not find any mutation in the three classic genes (Endoglin, Activin receptor-like kinase 1 or Mothers against decapentaplegic homolog 4), but identified in both cases an RASA1 mutation, known to cause CM-AVM1 syndrome.Conclusions Pulmonary AVM and portocaval shunt, usually encountered in HHT, have not yet been described in the CM-AVM1 syndrome. RASA1 screening may be considered in case of HHT suspicion, particularly when mutations are not found in the usually affected genes.
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Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Mutación , Fenotipo , Telangiectasia Hemorrágica Hereditaria/diagnóstico , Telangiectasia Hemorrágica Hereditaria/genética , Proteína Activadora de GTPasa p120/genética , Adulto , Alelos , Biopsia , Niño , Angiografía por Tomografía Computarizada , Diagnóstico Diferencial , Femenino , Genotipo , Humanos , Masculino , Análisis de Secuencia de ADN , Evaluación de Síntomas , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Heritable pulmonary arterial hypertension (PAH) is most commonly due to heterozygous mutations of the BMPR2 gene. Based on expert consensus, guidelines recommend annual screening echocardiography in asymptomatic BMPR2 mutation carriers. The main objectives of this study were to evaluate the characteristics of asymptomatic BMPR2 mutation carriers, assess their risk of occurrence of PAH and detect PAH at an early stage in this high-risk population. METHODS: Asymptomatic BMPR2 mutation carriers underwent screening at baseline and annually for a minimum of 2â years (DELPHI-2 study; ClinicalTrials.gov: NCT01600898). Annual screening included clinical assessment, ECG, pulmonary function tests, 6-min walk distance, cardiopulmonary exercise testing, chest radiography, echocardiography and brain natriuretic peptide (BNP) or N-terminal (NT)-proBNP level. Right heart catheterisation (RHC) was performed based on predefined criteria. An optional RHC at rest and exercise was proposed at baseline. RESULTS: 55 subjects (26 males; median age 37â years) were included. At baseline, no PAH was suspected based on echocardiography and NT-proBNP levels. All subjects accepted RHC at inclusion, which identified two mild PAH cases (3.6%) and 12 subjects with exercise pulmonary hypertension (21.8%). At long-term follow-up (118.8â patient-years of follow-up), three additional cases were diagnosed, yielding a PAH incidence of 2.3% per year (0.99% per year in males and 3.5% per year in females). All PAH cases remained at low-risk status on oral therapy at last follow-up. CONCLUSIONS: Asymptomatic BMPR2 mutation carriers have a significant risk of developing incident PAH. International multicentre studies are needed to confirm that refined multimodal screening programmes with regular follow-up allow early detection of PAH.
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Hipertensión Pulmonar , Hipertensión Arterial Pulmonar , Adulto , Receptores de Proteínas Morfogenéticas Óseas de Tipo II/genética , Hipertensión Pulmonar Primaria Familiar/genética , Femenino , Humanos , Hipertensión Pulmonar/epidemiología , Hipertensión Pulmonar/genética , Masculino , Mutación , Factores de RiesgoRESUMEN
Background - Approximately 25% of patients with pulmonary arterial hypertension (PAH) have been found to harbor rare mutations in disease-causing genes. To identify missing heritability in PAH we integrated deep phenotyping with whole-genome sequencing data using Bayesian statistics. Methods - We analyzed 13,037 participants enrolled in the NIHR BioResource - Rare Diseases (NBR) study, of which 1,148 were recruited to the PAH domain. To test for genetic associations between genes and selected phenotypes of pulmonary hypertension (PH), we used the Bayesian rare-variant association method BeviMed. Results - Heterozygous, high impact, likely loss-of-function variants in the Kinase Insert Domain Receptor (KDR) gene were strongly associated with significantly reduced transfer coefficient for carbon monoxide (KCO, posterior probability (PP)=0.989) and older age at diagnosis (PP=0.912). We also provide evidence for familial segregation of a rare nonsense KDR variant with these phenotypes. On computed tomographic imaging of the lungs, a range of parenchymal abnormalities were observed in the five patients harboring these predicted deleterious variants in KDR. Four additional PAH cases with rare likely loss-of-function variants in KDR were independently identified in the US PAH Biobank cohort with similar phenotypic characteristics. Conclusions - The Bayesian inference approach allowed us to independently validate KDR, which encodes for the Vascular Endothelial Growth Factor Receptor 2 (VEGFR2), as a novel PAH candidate gene. Furthermore, this approach specifically associated high impact likely loss-of-function variants in the genetically constrained gene with distinct phenotypes. These findings provide evidence for KDR being a clinically actionable PAH gene and further support the central role of the vascular endothelium in the pathobiology of PAH.
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Pulmonary veno-occlusive disease (PVOD) occurs in humans either as a heritable form (hPVOD) due to biallelic inactivating mutations of EIF2AK4 (encoding GCN2) or as a sporadic form in older age (sPVOD). The chemotherapeutic agent mitomycin C (MMC) is a potent inducer of PVOD in humans and in rats (MMC-PVOD). Here, we compared human hPVOD and sPVOD, and MMC-PVOD pathophysiology at the histological, cellular, and molecular levels to unravel common altered pathomechanisms. MMC exposure in rats was associated primarily with arterial and microvessel remodeling, and secondarily by venous remodeling, when PVOD became symptomatic. In all forms of PVOD tested, there was convergent GCN2-dependent but eIF2α-independent pulmonary protein overexpression of HO-1 (heme oxygenase 1) and CHOP (CCAAT-enhancer-binding protein [C/EBP] homologous protein), two downstream effectors of GCN2 signaling and endoplasmic reticulum stress. In human PVOD samples, CHOP immunohistochemical staining mainly labeled endothelial cells in remodeled veins and arteries. Strong HO-1 staining was observed only within capillary hemangiomatosis foci, where intense microvascular proliferation occurs. HO-1 and CHOP stainings were not observed in control and pulmonary arterial hypertension lung tissues, supporting the specificity for CHOP and HO-1 involvement in PVOD pathobiology. In vivo loss of GCN2 (EIF2AK4 mutations carriers and Eif2ak4-/- rats) or in vitro GCN2 inhibition in cultured pulmonary artery endothelial cells using pharmacological and siRNA approaches demonstrated that GCN2 loss of function negatively regulates BMP (bone morphogenetic protein)-dependent SMAD1/5/9 signaling. Exogenous BMP9 was still able to reverse GCN2 inhibition-induced proliferation of pulmonary artery endothelial cells. In conclusion, we identified CHOP and HO-1 inhibition, and BMP9, as potential therapeutic options for PVOD.
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Enfermedad Veno-Oclusiva Pulmonar/metabolismo , Enfermedad Veno-Oclusiva Pulmonar/patología , Animales , Modelos Animales de Enfermedad , Células Endoteliales/metabolismo , Células Endoteliales/patología , Humanos , Hipertensión Pulmonar/metabolismo , Hipertensión Pulmonar/patología , Pulmón/metabolismo , Pulmón/patología , Mutación/genética , Arteria Pulmonar/metabolismo , Arteria Pulmonar/patología , Ratas , Transducción de Señal/fisiología , Factor de Transcripción CHOP/metabolismoRESUMEN
INTRODUCTION: TBX4 mutation causes small patella syndrome (SPS) and/or pulmonary arterial hypertension (PAH). The characteristics and outcomes of PAH associated with TBX4 mutations are largely unknown. METHODS: We report the clinical, functional, radiologic, histologic and haemodynamic characteristics and outcomes of heritable PAH patients carrying a TBX4 mutation from the French pulmonary hypertension (PH) network. RESULTS: 20 patients were identified in 17 families. They were characterised by a median age at diagnosis of 29â years (0-76â years) and a female to male ratio of three. Most of the patients (70%) were in New York Heart Association (NYHA) functional class III or IV with a severe haemodynamic impairment (median pulmonary vascular resistance (PVR) of 13.6 (6.2-41.8) Wood units). Skeletal signs of SPS were present in 80% of cases. Half of the patients had mild restrictive or obstructive limitation and diffusing capacity of the lung for carbon monoxide (D LCO) was decreased in all patients. High-resolution computed tomography (HRCT) showed bronchial abnormalities, peri-bronchial cysts, mosaic distribution and mediastinal lymphadenopathies. PAH therapy was associated with significant clinical improvement. At follow-up (median 76â months), two patients had died and two had undergone lung transplantation. One-year, three-year and five-year event-free survival rates were 100%, 94% and 83%, respectively. Histologic examination of explanted lungs revealed alveolar growth abnormalities, major pulmonary vascular remodelling similar to that observed in idiopathic pulmonary arterial hypertension (IPAH) and accumulation of cholesterol crystals within the lung parenchyma. CONCLUSION: PAH due to TBX4 mutations may occur with or without skeletal abnormalities across a broad age range from birth to late adulthood. PAH is usually severe and associated with bronchial and parenchymal abnormalities.