Transcription factors in the pathogenesis of pulmonary arterial hypertension—Current knowledge and therapeutic potential

Pulmonary arterial hypertension (PAH) is a disease characterized by elevated pulmonary vascular resistance and pulmonary artery pressure. Mortality remains high in severe cases despite significant advances in management and pharmacotherapy. Since currently approved PAH therapies are unable to significantly reverse pathological vessel remodeling, novel disease-modifying, targeted therapeutics are needed. Pathogenetically, PAH is characterized by vessel wall cell dysfunction with consecutive remodeling of the pulmonary vasculature and the right heart. Transcription factors (TFs) regulate the process of transcribing DNA into RNA and, in the pulmonary circulation, control the response of pulmonary vascular cells to macro- and microenvironmental stimuli. Often, TFs form complex protein interaction networks with other TFs or co-factors to allow for fine-tuning of gene expression. Therefore, identification of the underlying molecular mechanisms of TF (dys-)function is essential to develop tailored modulation strategies in PAH. This current review provides a compendium-style overview of TFs and TF complexes associated with PAH pathogenesis and highlights their potential as targets for vasculoregenerative or reverse remodeling therapies

Idiopathic pulmonary arterial hypertension phenotypes determined by cluster analysis from the COMPERA registry

Funding Information: Marius M. Hoeper has received fees for lectures and/or consultations from Acceleron, Actelion, Bayer, MSD, and Pfizer. Nicola Benjamin has received fees for lectures and/or consultations from Actelion. Ekkehard Grünig has received fees for lectures and/or consultations from Actelion, Bayer, GSK, MSD, United Therapeutics, and Pfizer. Karen M. Olsson has received fees for lectures and/or consultations from Actelion, Bayer, United Therapeutics, GSK, and Pfizer. C. Dario Vizza has received fees from Actelion, Bayer, GSK, MSD, Pfizer, and United Therapeutics Europe. Anton Vonk-Noordegraaf has received fees for lectures and/or consultation from Actelion, Bayer, GSK, and MSD. Oliver Distler has/had a consultancy relationship with and/or has received research funding from 4-D Science, Actelion, Active Biotec, Bayer, Biogen Idec, Boehringer Ingelheim Pharma, BMS, ChemoAb, EpiPharm, Ergonex, espeRare foundation, GSK, Genentech/Roche, Inventiva, Lilly, medac, MedImmune, Mitsubishi Tanabe, Pharmacyclics, Pfizer, Sanofi, Serodapharm, and Sinoxa in the area of potential treatments of scleroderma and its complications including pulmonary arterial hypertension. In addition, Prof Distler has a patent for mir-29 for the treatment of systemic sclerosis licensed. Christian Opitz has received fees from Actelion, Bayer, GSK, Pfizer, and Novartis. J. Simon R. Gibbs has received fees for lectures and/or consultations from Actelion, Bayer, Bellerophon, GSK, MSD, and Pfizer. Marion Delcroix has received fees from Actelion, Bayer, GSK, and MSD. H. Ardeschir Ghofrani has received fees from Actelion, Bayer, Gilead, GSK, MSD, Pfizer, and United Therapeutics. Doerte Huscher has received fees for lectures and consultations from Actelion. David Pittrow has received fees for consultations from Actelion, Biogen, Aspen, Bayer, Boehringer Ingelheim, Daiichi Sankyo, and Sanofi. Stephan Rosenkranz has received fees for lectures and/or consultations from Actelion, Bayer, GSK, Pfizer, Novartis, Gilead, MSD, and United Therapeutics. Martin Claussen reports honoraria for lectures from Boehringer Ingelheim Pharma GmbH and Roche Pharma and for serving on advisory boards from Boehringer Ingelheim, outside the submitted work. Heinrike Wilkens reports personal fees from Boehringer and Roche during the conduct of the study and personal fees from Bayer, Biotest, Actelion, GSK, and Pfizer outside the submitted work. Juergen Behr received grants from Boehringer Ingelheim and personal fees for consultation or lectures from Actelion, Bayer, Boehringer Ingelheim, and Roche. Hubert Wirtz reports personal fees from Boehringer Ingelheim and Roche outside the submitted work. Hening Gall reports personal fees from Actelion, AstraZeneca, Bayer, BMS, GSK, Janssen-Cilag, Lilly, MSD, Novartis, OMT, Pfizer, and United Therapeutics outside the submitted work. Elena Pfeuffer-Jovic reports personal fees from Actelion, Boehringer Ingelheim, Novartis, and OMT outside the submitted work. Laura Scelsi reports personal fees from Actelion, Bayer, and MSD outside the submitted work. Siliva Ulrich reports grants from Swiss National Science Foundation, Zurich Lung, Swiss Lung, and Orpha Swiss, and grants and personal fees from Actelion SA/Johnson & Johnson Switzerland and MSD Switzerland outside the submitted work. The remaining authors have no conflicts of interest to disclose. Funding Information: This work was supported by the German Centre of Lung Research (DZL). COMPERA is funded by unrestricted grants from Acceleron , Actelion Pharmaceuticals , Bayer , OMT , and GSK . These companies were not involved in data analysis or the writing of this manuscript. Publisher Copyright: © 2020 The Authors Copyright: Copyright 2020 Elsevier B.V., All rights reserved.The term idiopathic pulmonary arterial hypertension (IPAH) is used to categorize patients with pre-capillary pulmonary hypertension of unknown origin. There is considerable variability in the clinical presentation of these patients. Using data from the Comparative, Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension, we performed a cluster analysis of 841 patients with IPAH based on age, sex, diffusion capacity of the lung for carbon monoxide (DLCO; <45% vs ≥45% predicted), smoking status, and presence of comorbidities (obesity, hypertension, coronary heart disease, and diabetes mellitus). A hierarchical agglomerative clustering algorithm was performed using Ward's minimum variance method. The clusters were analyzed in terms of baseline characteristics; survival; and response to pulmonary arterial hypertension (PAH) therapy, expressed as changes from baseline to follow-up in functional class, 6-minute walking distance, cardiac biomarkers, and risk. Three clusters were identified: Cluster 1 (n = 106; 12.6%): median age 45 years, 76% females, no comorbidities, mostly never smokers, DLCO ≥45%; Cluster 2 (n = 301; 35.8%): median age 75 years, 98% females, frequent comorbidities, no smoking history, DLCO mostly ≥45%; and Cluster 3 (n = 434; 51.6%): median age 72 years, 72% males, frequent comorbidities, history of smoking, and low DLCO. Patients in Cluster 1 had a better response to PAH treatment than patients in the 2 other clusters. Survival over 5 years was 84.6% in Cluster 1, 59.2% in Cluster 2, and 42.2% in Cluster 3 (unadjusted p < 0.001 for comparison between all groups). The population of patients diagnosed with IPAH is heterogenous. This cluster analysis identified distinct phenotypes, which differed in clinical presentation, response to therapy, and survival.publishersversionPeer reviewe

Riociguat treatment in patients with chronic thromboembolic pulmonary hypertension: Final safety data from the EXPERT registry

Objective: The soluble guanylate cyclase stimulator riociguat is approved for the treatment of adult patients with pulmonary arterial hypertension (PAH) and inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH) following Phase

The Endothelial ADMA/NO Pathway in Hypoxia-Related Chronic Respiratory Diseases

Since its discovery, many adhere to the view that asymmetric dimethylarginine (ADMA), as an inhibitor of the synthesis of nitric oxide (NO), contributes to the pathogenesis of various diseases. Particularly, this is evident in disease of the cardiovascular system, in which endothelial dysfunction results in an imbalance between vasoconstriction and vasodilatation. Even if increased ADMA concentrations are closely related to an endothelial dysfunction, several studies pointed to a potential beneficial effect of ADMA, mainly in the context of angioproliferative disease such as cancer and fibrosis. Antiproliferative properties of ADMA independent of NO have been identified in this context. In particular, the regulation of ADMA by its degrading enzyme dimethylarginine dimethylaminohydrolase (DDAH) is the object of many studies. DDAH is discussed as a promising therapeutic target for the indirect regulation of NO. In hypoxia-related chronic respiratory diseases, this controversy discussion of ADMA and DDAH is particularly evident and is therefore subject of this review

Endoscopic lung volume reduction coil treatment in patients with very low FEV: an observational study

Background: Endoscopic lung volume reduction coil (LVRC) treatment is a therapeutic option for selected patients with advanced emphysema. The effects and the safety of endoscopic lung volume reduction in patients with very low forced expired volume in one second (FEV 1 ) remain to be determined. This study was conducted to assess the effects and the safety of LVRC treatment in patients with very low FEV 1 . Methods: The study was performed as a retrospective observational study in the Department of Respiratory Medicine at the University Medical Center Hamburg-Eppendorf on patients with very low FEV 1 , defined as an FEV 1 ⩽ 20% of predicted at baseline in whom LVRC treatment was performed between 1 April 2012 and 28 February 2017. Results: LVRC treatment was performed in 33 patients with very low FEV 1 . Of these, 45.5% were female and 54.5% were male. At baseline, mean FEV 1 was 0.46 ± 0.12 liters (15 ± 3% of predicted), mean forced vital capacity (FVC) was 1.61 ± 0.62 liters (42 ± 13% of predicted), mean residual volume (RV) was 6.03 ± 0.81 liters (275 ± 51% of predicted) and 6-minute walk distance was 229 ± 102 m. Bilateral LVRC treatment was completed in 21 of these patients (63.6%). Bilateral LVRC treatment led to significant improvements in functional parameters with an increase in mean FEV 1 from 0.44 ± 0.11 liters to 0.54 ± 0.12 liters ( p = 0.001), equivalent to a relative improvement of 24.5 ± 26.9%, an increase in mean FVC from 1.49 ± 0.54 liters to 1.84 ± 0.49 liters ( p = 0.001), a decrease in mean RV from 6.27 ± 0.83 liters to 5.83 ± 1.09 liters ( p = 0.004) and an improvement in 6-minute walk distance from 218 ± 91 m to 266 ± 96 m ( p = 0.01). There were no cases of respiratory failure requiring mechanical ventilation and no deaths. Conclusions: LVRC treatment was effective and safe in patients with very low FEV 1

Endoscopic lung volume reduction coil treatment in patients with chronic hypercapnic respiratory failure: an observational study

Background: Endoscopic lung volume reduction coil (LVRC) treatment is an option for selected patients with severe emphysema. In the advanced stages, emphysema leads to respiratory failure: hypoxemia and eventually chronic hypercapnic respiratory failure. It can be hypothesized that LVRC treatment, a procedure targeting hyperinflation and thereby reducing ventilatory workload, may be especially beneficial in patients with chronic hypercapnic respiratory failure. This study was conducted to gain first insights into the effects and the safety of LVRC treatment in patients with emphysema and chronic hypercapnic respiratory failure. Methods: A retrospective observational study conducted in the Department of Respiratory Medicine at the University Medical Center Hamburg-Eppendorf, Germany on all patients with chronic hypercapnic respiratory failure in whom bilateral LVRC treatment was performed between 1 April 2012 and 30 September 2015. Results: During the study period, bilateral LVRC treatment was performed in 10 patients with chronic hypercapnic respiratory failure. Compared with baseline, bilateral LVRC treatment led to a significant increase in mean forced expiratory volume in one second (FEV 1 ) from 0.5 ± 0.1 l to 0.6 ± 0.2 l ( p = 0.004), a decrease in residual volume (RV) from 6.1 ± 0.9 l to 5.6 ± 1.1 l ( p = 0.02) and a reduction in partial pressure of carbon dioxide in arterial blood (PaCO 2 ) from 53 ± 5 mmHg to 48 ± 4 mmHg ( p = 0.03). One case of hemoptysis requiring readmission to hospital was the only severe adverse event. Conclusions: LVRC treatment was safe and effective in patients with nonsevere chronic hypercapnic respiratory failure. It led not only to an improvement in lung function but also to a significant decrease in PaCO 2

Genetic evidence for a causative effect of airflow obstruction on left ventricular filling: a Mendelian randomisation study

Background!#!Observational studies on the general population have suggested that airflow obstruction associates with left ventricular (LV) filling. To limit the influence of environmental risk factors/exposures, we used a Mendelian randomisation (MR) approach based on common genetic variations and tested whether a causative relation between airflow obstruction and LV filling can be detected.!##!Methods!#!We used summary statistics from large genome-wide association studies (GWAS) on the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC) measured by spirometry and the LV end-diastolic volume (LVEDV) as assessed by cardiac magnetic resonance imaging. The primary MR was based on an inverse variance weighted regression. Various complementary MR methods and subsets of the instrument variables were used to assess the plausibility of the findings.!##!Results!#!We obtained consistent evidence in our primary MR analysis and subsequent sensitivity analyses that reducing airflow obstruction leads to increased inflow to the LV (odds ratio [OR] from inverse variance weighted regression 1.05, 95% confidence interval [CI] 1.01-1.09, P = 0.0172). Sensitivity analyses indicated a certain extent of negative horizontal pleiotropy and the estimate from biased-corrected MR-Egger was adjusted upward (OR 1.2, 95% CI 1.09-1.31, P &amp;lt; 0.001). Prioritisation of single genetic variants revealed rs995758, rs2070600 and rs7733410 as major contributors to the MR result.!##!Conclusion!#!Our findings indicate a causal relationship between airflow obstruction and LV filling in the general population providing genetic context to observational associations. The results suggest that targeting (even subclinical) airflow obstruction can lead to direct cardiac improvements, demonstrated by an increase in LVEDV. Functional annotation of single genetic variants contributing most to the causal effect estimate could help to prioritise biological underpinnings

Recent advances in pulmonary arterial hypertension [version 1; referees: 2 approved]

Pulmonary arterial hypertension (PAH) is a rare disorder with a high mortality rate. Treatment options have improved in the last 20 years, but patients still die prematurely of right heart failure. Though rare, it is heterogeneous at the genetic and molecular level, and understanding and exploiting this is key to the development of more effective treatments. BMPR2, encoding bone morphogenetic receptor type 2, is the most commonly affected gene in both familial and non-familial PAH, but rare mutations have been identified in other genes. Transcriptomic, proteomic, and metabolomic studies looking for endophenotypes are under way. There is no shortage of candidate new drug targets for PAH, but the selection and prioritisation of these are challenges for the research community