Chemosensory Cell-Derived Acetylcholine Drives Tracheal Mucociliary Clearance in Response to Virulence-Associated Formyl Peptides.

Mucociliary clearance through coordinated ciliary beating is a major innate defense removing pathogens from the lower airways, but the pathogen sensing and downstream signaling mechanisms remain unclear. We identified virulence-associated formylated bacterial peptides that potently stimulated ciliary-driven transport in the mouse trachea. This innate response was independent of formyl peptide and taste receptors but depended on key taste transduction genes. Tracheal cholinergic chemosensory cells expressed these genes, and genetic ablation of these cells abrogated peptide-driven stimulation of mucociliary clearance. Trpm5-deficient mice were more susceptible to infection with a natural pathogen, and formylated bacterial peptides were detected in patients with chronic obstructive pulmonary disease. Optogenetics and peptide stimulation revealed that ciliary beating was driven by paracrine cholinergic signaling from chemosensory to ciliated cells operating through muscarinic M3 receptors independently of nerves. We provide a cellular and molecular framework that defines how tracheal chemosensory cells integrate chemosensation with innate defense.

An essential function for autocrine hedgehog signaling in epithelial proliferation and differentiation in the trachea.

The tracheal epithelium is a primary target for pulmonary diseases as it provides a conduit for air flow between the environment and the lung lobes. The cellular and molecular mechanisms underlying airway epithelial cell proliferation and differentiation remain poorly understood. Hedgehog (HH) signaling orchestrates communication between epithelial and mesenchymal cells in the lung, where it modulates stromal cell proliferation, differentiation and signaling back to the epithelium. Here, we reveal a previously unreported autocrine function of HH signaling in airway epithelial cells. Epithelial cell depletion of the ligand sonic hedgehog (SHH) or its effector smoothened (SMO) causes defects in both epithelial cell proliferation and differentiation. In cultured primary human airway epithelial cells, HH signaling inhibition also hampers cell proliferation and differentiation. Epithelial HH function is mediated, at least in part, through transcriptional activation, as HH signaling inhibition leads to downregulation of cell type-specific transcription factor genes in both the mouse trachea and human airway epithelial cells. These results provide new insights into the role of HH signaling in epithelial cell proliferation and differentiation during airway development.

Adiponectin suppresses stiffness-dependent, profibrotic activation of lung fibroblasts.

Idiopathic pulmonary fibrosis (IPF) is a progressive, irreversible respiratory disease with limited therapeutic options. A hallmark of IPF is excessive fibroblast activation and extracellular matrix (ECM) deposition. The resulting increase in tissue stiffness amplifies fibroblast activation and drives disease progression. Dampening stiffness-dependent activation of fibroblasts could slow disease progression. We performed an unbiased, next-generation sequencing (NGS) screen to identify signaling pathways involved in stiffness-dependent lung fibroblast activation. Adipocytokine signaling was downregulated in primary lung fibroblasts (PFs) cultured on stiff matrices. Re-activating adipocytokine signaling with adiponectin suppressed stiffness-dependent activation of human PFs. Adiponectin signaling depended on CDH13 expression and p38 mitogen-activated protein kinase gamma (p38MAPKγ) activation. CDH13 expression and p38MAPKγ activation were strongly reduced in lungs from IPF donors. Our data suggest that adiponectin-signaling via CDH13 and p38MAPKγ activation suppresses profibrotic activation of fibroblasts in the lung. Targeting of the adiponectin signaling cascade may provide therapeutic benefits in IPF.NEW & NOTEWORTHY A hallmark of idiopathic pulmonary fibrosis (IPF) is excessive fibroblast activation and extracellular matrix (ECM) deposition. The resulting increase in tissue stiffness amplifies fibroblast activation and drives disease progression. Dampening stiffness-dependent activation of fibroblasts could slow disease progression. We found that activation of the adipocytokine signaling pathway halts and reverses stiffness-induced, profibrotic fibroblast activation. Specific targeting of this signaling cascade may therefore provide therapeutic benefits in IPF.

Multilineage murine stem cells generate complex organoids to model distal lung development and disease.

Organoids derived from mouse and human stem cells have recently emerged as a powerful tool to study organ development and disease. We here established a three-dimensional (3D) murine bronchioalveolar lung organoid (BALO) model that allows clonal expansion and self-organization of FACS-sorted bronchioalveolar stem cells (BASCs) upon co-culture with lung-resident mesenchymal cells. BALOs yield a highly branched 3D structure within 21 days of culture, mimicking the cellular composition of the bronchioalveolar compartment as defined by single-cell RNA sequencing and fluorescence as well as electron microscopic phenotyping. Additionally, BALOs support engraftment and maintenance of the cellular phenotype of injected tissue-resident macrophages. We also demonstrate that BALOs recapitulate lung developmental defects after knockdown of a critical regulatory gene, and permit modeling of viral infection. We conclude that the BALO model enables reconstruction of the epithelial-mesenchymal-myeloid unit of the distal lung, thereby opening numerous new avenues to study lung development, infection, and regenerative processes in vitro.

Evidence for a lipofibroblast-to- Cthrc1 + myofibroblast reversible switch during the development and resolution of lung fibrosis in young mice.

BACKGROUND: Fibrosis is often associated with aberrant repair mechanisms that ultimately lead to organ failure. In the lung, idiopathic pulmonary fibrosis (IPF) is a fatal form of interstitial lung disease (ILD) to which there is currently no curative therapy. From the cell biology point of view, the cell of origin and eventual fate of activated myofibroblasts (aMYFs) have taken center stage as these cells are believed to drive structural remodeling and lung function impairment. While aMYFs are now widely believed to originate from resident fibroblasts, the heterogeneity of aMYFs and ultimate fate during fibrosis resolution remain elusive. We have previously shown that aMYFs dedifferentiation and acquisition of a lipofibroblast (LIF)-like phenotype represent a route of fibrosis resolution. METHODS: In this study, we combined genetic lineage tracing and single-cell transcriptomics in mice, and data mining of human IPF datasets to decipher the heterogeneity of aMYFs and investigate differentiation trajectories during fibrosis resolution. Furthermore, organoid cultures were utilized as a functional readout for the alveolar mesenchymal niche activity during various phases of injury and repair in mice. RESULTS: Our data demonstrate that aMYFs consist of four subclusters displaying unique pro-alveologenic versus profibrotic profiles. Alveolar fibroblasts displaying a high LIF-like signature largely constitute both the origin and fate of aMYFs during fibrogenesis and resolution respectively. The heterogeneity of aMYFs is conserved in humans and a significant proportion of human aMYFs displays a high LIF signature. CONCLUSION: Our work identifies a subcluster of aMYFs that is potentially relevant for future management of IPF.

Transforming Growth Factor-ß1 Regulates Peroxisomal Genes/Proteins via Smad Signaling in Idiopathic Pulmonary Fibrosis Fibroblasts and Transgenic Mouse Models.

Idiopathic pulmonary fibrosis (IPF) is a chronic human disease with persistent destruction of lung parenchyma. Transforming growth factor-ß1 (TGF-ß1) signaling plays a pivotal role in the initiation and pathogenesis of IPF. As shown herein, TGF-ß1 signaling down-regulated not only peroxisome biogenesis but also the metabolism of these organelles in human IPF fibroblasts. In vitro cell culture observations in human fibroblasts and human lung tissue indicated that peroxisomal biogenesis and metabolic proteins were significantly down-regulated in the lung of 1-month-old transgenic mice expressing a constitutively active TGF-ß type I receptor kinase (ALK5). The peroxisome biogenesis protein peroxisomal membrane protein Pex13p (PEX13p) as well as the peroxisomal lipid metabolic enzyme peroxisomal acyl-coenzyme A oxidase 1 (ACOX1) and antioxidative enzyme catalase were highly up-regulated in TGF-ß type II receptor and Smad3 knockout mice. This study reports a novel mechanism of peroxisome biogenesis and metabolic regulation via TGF-ß1-Smad signaling: interaction of the Smad3 transcription factor with the PEX13 gene in chromatin immunoprecipitation-on-chip assay as well as in a bleomycin-induced pulmonary fibrosis model applied to TGF-ß type II receptor knockout mice. Taken together, data from this study suggest that TGF-ß1 participates in regulation of peroxisomal biogenesis and metabolism via Smad-dependent signaling, opening up novel strategies for the development of therapeutic approaches to inhibit progression of pulmonary fibrosis patients with IPF.

It takes two peroxisome proliferator-activated receptors (PPAR-ß/δ and PPAR-γ) to tango idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterized by aberrant lung epithelial phenotypes, fibroblast activation, and increased extracellular matrix deposition. Transforming growth factor-beta (TGF-ß)1-induced Smad signaling and downregulation of peroxisomal genes are involved in the pathogenesis and can be inhibited by peroxisome proliferator-activated receptor (PPAR)-α activation. However, the three PPARs, that is PPAR-α, PPAR-ß/δ, and PPAR-γ, are known to interact in a complex crosstalk. METHODS: To mimic the pathogenesis of lung fibrosis, primary lung fibroblasts from control and IPF patients with comparable levels of all three PPARs were treated with TGF-ß1 for 24 h, followed by the addition of PPAR ligands either alone or in combination for another 24 h. Fibrosis markers (intra- and extracellular collagen levels, expression and activity of matrix metalloproteinases) and peroxisomal biogenesis and metabolism (gene expression of peroxisomal biogenesis and matrix proteins, protein levels of PEX13 and catalase, targeted and untargeted lipidomic profiles) were analyzed after TGF-ß1 treatment and the effects of the PPAR ligands were investigated. RESULTS: TGF-ß1 induced the expected phenotype; e.g. it increased the intra- and extracellular collagen levels and decreased peroxisomal biogenesis and metabolism. Agonists of different PPARs reversed TGF-ß1-induced fibrosis even when given 24 h after TGF-ß1. The effects included the reversals of (1) the increase in collagen production by repressing COL1A2 promoter activity (through PPAR-ß/δ activation); (2) the reduced activity of matrix metalloproteinases (through PPAR-ß/δ activation); (3) the decrease in peroxisomal biogenesis and lipid metabolism (through PPAR-γ activation); and (4) the decrease in catalase protein levels in control (through PPAR-γ activation) and IPF (through a combined activation of PPAR-ß/δ and PPAR-γ) fibroblasts. Further experiments to explore the role of catalase showed that an overexpression of catalase protein reduced collagen production. Additionally, the beneficial effect of PPAR-γ but not of PPAR-ß/δ activation on collagen synthesis depended on catalase activity and was thus redox-sensitive. CONCLUSION: Our data provide evidence that IPF patients may benefit from a combined activation of PPAR-ß/δ and PPAR-γ.

Hospitalisation patterns in interstitial lung diseases: data from the EXCITING-ILD registry.

BACKGROUND: Interstitial lung diseases (ILD) comprise a heterogeneous group of mainly chronic lung diseases with more than 200 entities and relevant differences in disease course and prognosis. Little data is available on hospitalisation patterns in ILD. METHODS: The EXCITING-ILD (Exploring Clinical and Epidemiological Characteristics of Interstitial Lung Diseases) registry was analysed for hospitalisations. Reasons for hospitalisation were classified as all cause, ILD-related and respiratory hospitalisations, and patients were analysed for frequency of hospitalisations, time to first non-elective hospitalisation, mortality and progression-free survival. Additionally, the risk for hospitalisation according to GAP index and ILD subtype was calculated by Cox proportional-hazard models as well as influencing factors on prediction of hospitalisation by logistic regression with forward selection. RESULTS: In total, 601 patients were included. 1210 hospitalisations were recorded during the 6 months prior to registry inclusion until the last study visit. 800 (66.1%) were ILD-related, 59.3% of admissions were registered in the first year after inclusion. Mortality was associated with all cause, ILD-related and respiratory-related hospitalisation. Risk factors for hospitalisation were advanced disease (GAP Index stages II and III) and CTD (connective tissue disease)-ILDs. All cause hospitalisations were associated with pulmonary hypertension (OR 2.53, p = 0.005). ILD-related hospitalisations were associated with unclassifiable ILD and concomitant emphysema (OR = 2.133, p = 0.001) as well as with other granulomatous ILDs and a positive smoking status (OR = 3.082, p = 0.005). CONCLUSION: Our results represent a crucial contribution in understanding predisposing factors for hospitalisation in ILD and its major impact on mortality. Further studies to characterize the most vulnerable patient group as well as approaches to prevent hospitalisations are warranted.

Disease trajectories in interstitial lung diseases - data from the EXCITING-ILD registry.

BACKGROUND: Interstitial lung diseases (ILD) comprise a heterogeneous group of mainly chronic lung diseases with different disease trajectories. Progression (PF-ILD) occurs in up to 50% of patients and is associated with increased mortality. METHODS: The EXCITING-ILD (Exploring Clinical and Epidemiological Characteristics of Interstitial Lung Diseases) registry was analysed for disease trajectories in different ILD. The course of disease was classified as significant (absolute forced vital capacity FVC decline > 10%) or moderate progression (FVC decline 5-10%), stable disease (FVC decline or increase < 5%) or improvement (FVC increase ≥ 5%) during time in registry. A second definition for PF-ILD included absolute decline in FVC % predicted ≥ 10% within 24 months or ≥ 1 respiratory-related hospitalisation. Risk factors for progression were determined by Cox proportional-hazard models and by logistic regression with forward selection. Kaplan-Meier curves were utilised to estimate survival time and time to progression. RESULTS: Within the EXCITING-ILD registry 28.5% of the patients died (n = 171), mainly due to ILD (n = 71, 41.5%). Median survival time from date of diagnosis on was 15.5 years (range 0.1 to 34.4 years). From 601 included patients, progression was detected in 50.6% of the patients (n = 304) with shortest median time to progression in idiopathic NSIP (iNSIP; median 14.6 months) and idiopathic pulmonary fibrosis (IPF; median 18.9 months). Reasons for the determination as PF-ILD were mainly deterioration in lung function (PFT; 57.8%) and respiratory hospitalisations (40.6%). In multivariate analyses reduced baseline FVC together with age were significant predictors for progression (OR = 1.00, p < 0.001). Higher GAP indices were a significant risk factor for a shorter survival time (GAP stage III vs. I HR = 9.06, p < 0.001). A significant shorter survival time was found in IPF compared to sarcoidosis (HR = 0.04, p < 0.001), CTD-ILD (HR = 0.33, p < 0.001), and HP (HR = 0.30, p < 0.001). Patients with at least one reported ILD exacerbation as a reason for hospitalisation had a median survival time of 7.3 years (range 0.1 to 34.4 years) compared to 19.6 years (range 0.3 to 19.6 years) in patients without exacerbations (HR = 0.39, p < 0.001). CONCLUSION: Disease progression is common in all ILD and associated with increased mortality. Most important risk factors for progression are impaired baseline forced vital capacity and higher age, as well as acute exacerbations and respiratory hospitalisations for mortality. Early detection of progression remains challenging, further clinical criteria in addition to PFT might be helpful.

Pharmacological Treatment of Idiopathic Pulmonary Fibrosis (Update) and Progressive Pulmonary Fibroses S2k Guideline of the German Respiratory Society.

Interstitial lung diseases (ILD) are characterized by a variable degree of inflammatory and fibrotic changes within the alveolar space and distal airways (bronchioles). An inverse correlation exists between the extent of fibrosis and the possibility that an ILD is reversible. While the acute (inflammatory) type of extrinsic allergic alveolitis may resolve without sequelae (restitutio ad integrum), IPF is the prototypic fibrotic ILD with a progressive course, leading to an irreversible and progressive fibrosis of the lung parenchyma. This guideline provides guidance on differnential pharmacological treatment approaches to different types of fibrotic interstitial lung diseases.

CEACAM6 as a Novel Therapeutic Target to Boost HO-1-mediated Antioxidant Defense in COPD.

Rationale: Tobacco smoking and air pollution are primary causes of chronic obstructive pulmonary disease (COPD). However, only a minority of smokers develop COPD. The mechanisms underlying the defense against nitrosative/oxidative stress in nonsusceptible smokers to COPD remain largely unresolved. Objectives: To investigate the defense mechanisms against nitrosative/oxidative stress that possibly prevent COPD development or progression. Methods: Four cohorts were investigated: 1) sputum samples (healthy, n = 4; COPD, n = 37), 2) lung tissue samples (healthy, n = 13; smokers without COPD, n = 10; smoker+COPD, n = 17), 3) pulmonary lobectomy tissue samples (no/mild emphysema, n = 6), and 4) blood samples (healthy, n = 6; COPD, n = 18). We screened 3-nitrotyrosine (3-NT) levels, as indication of nitrosative/oxidative stress, in human samples. We established a novel in vitro model of a cigarette smoke extract (CSE)-resistant cell line and studied 3-NT formation, antioxidant capacity, and transcriptomic profiles. Results were validated in lung tissue, isolated primary cells, and an ex vivo model using adeno-associated virus-mediated gene transduction and human precision-cut lung slices. Measurements and Main Results: 3-NT levels correlate with COPD severity of patients. In CSE-resistant cells, nitrosative/oxidative stress upon CSE treatment was attenuated, paralleled by profound upregulation of heme oxygenase-1 (HO-1). We identified carcinoembryonic antigen cell adhesion molecule 6 (CEACAM6) as a negative regulator of HO-1-mediated nitrosative/oxidative stress defense in human alveolar type 2 epithelial cells (hAEC2s). Consistently, inhibition of HO-1 activity in hAEC2s increased the susceptibility toward CSE-induced damage. Epithelium-specific CEACAM6 overexpression increased nitrosative/oxidative stress and cell death in human precision-cut lung slices on CSE treatment. Conclusions: CEACAM6 expression determines the hAEC2 sensitivity to nitrosative/oxidative stress triggering emphysema development/progression in susceptible smokers.

[Task Force Dyspnoe unit (DU)]. / Task Force Dyspnoe Unit (DU).

Acute dyspnoea is one of the most common internal medicine symptoms in the emergency department. It arises from an acute illness or from the exacerbation of a chronic illness. Symptom-related emergency structures and corresponding structural guidelines already exist in the stroke and chest pain units for dealing with the leading symptoms of acute stroke and acute chest pain. These are lacking in Germany for the key symptom of dyspnoea, although the benefits of these structures have already been proven in other countries. The German Society for Pneumology and Respiratory Medicine (DGP) has now set up a task force together with the Association of Pneumology Clinics (VPK), in order to deal with the topic and develop appropriate structural guidelines for such "dyspnoea units" in Germany. At the end of the process, the certification of such units at German hospitals is optional.

SPARC, a Novel Regulator of Vascular Cell Function in Pulmonary Hypertension.

BACKGROUND: Pulmonary hypertension (PH) is a life-threatening disease, characterized by excessive pulmonary vascular remodeling, leading to elevated pulmonary arterial pressure and right heart hypertrophy. PH can be caused by chronic hypoxia, leading to hyper-proliferation of pulmonary arterial smooth muscle cells (PASMCs) and apoptosis-resistant pulmonary microvascular endothelial cells (PMVECs). On reexposure to normoxia, chronic hypoxia-induced PH in mice is reversible. In this study, the authors aim to identify novel candidate genes involved in pulmonary vascular remodeling specifically in the pulmonary vasculature. METHODS: After microarray analysis, the authors assessed the role of SPARC (secreted protein acidic and rich in cysteine) in PH using lung tissue from idiopathic pulmonary arterial hypertension (IPAH) patients, as well as from chronically hypoxic mice. In vitro studies were conducted in primary human PASMCs and PMVECs. In vivo function of SPARC was proven in chronic hypoxia-induced PH in mice by using an adeno-associated virus-mediated Sparc knockdown approach. RESULTS: C57BL/6J mice were exposed to normoxia, chronic hypoxia, or chronic hypoxia with subsequent reexposure to normoxia for different time points. Microarray analysis of the pulmonary vascular compartment after laser microdissection identified Sparc as one of the genes downregulated at all reoxygenation time points investigated. Intriguingly, SPARC was vice versa upregulated in lungs during development of hypoxia-induced PH in mice as well as in IPAH, although SPARC plasma levels were not elevated in PH. TGF-ß1 (transforming growth factor ß1) or HIF2A (hypoxia-inducible factor 2A) signaling pathways induced SPARC expression in human PASMCs. In loss of function studies, SPARC silencing enhanced apoptosis and reduced proliferation. In gain of function studies, elevated SPARC levels induced PASMCs, but not PMVECs, proliferation. Coculture and conditioned medium experiments revealed that PMVECs-secreted SPARC acts as a paracrine factor triggering PASMCs proliferation. Contrary to the authors' expectations, in vivo congenital Sparc knockout mice were not protected from hypoxia-induced PH, most probably because of counter-regulatory proproliferative signaling. However, adeno-associated virus-mediated Sparc knockdown in adult mice significantly improved hemodynamic and cardiac function in PH mice. CONCLUSIONS: This study provides evidence for the involvement of SPARC in the pathogenesis of human PH and chronic hypoxia-induced PH in mice, most likely by affecting vascular cell function.

Fibroblast growth factor 10 reverses cigarette smoke- and elastase-induced emphysema and pulmonary hypertension in mice.

BACKGROUND: COPD is an incurable disease and a leading cause of death worldwide. In mice, fibroblast growth factor (FGF)10 is essential for lung morphogenesis, and in humans, polymorphisms in the human FGF10 gene correlate with an increased susceptibility to develop COPD. METHODS: We analysed FGF10 signalling in human lung sections and isolated cells from healthy donor, smoker and COPD lungs. The development of emphysema and PH was investigated in Fgf10+/- and Fgfr2b+/- (FGF receptor 2b) mice upon chronic exposure to cigarette smoke. In addition, we overexpressed FGF10 in mice following elastase- or cigarette smoke-induced emphysema and pulmonary hypertension (PH). RESULTS: We found impaired FGF10 expression in human lung alveolar walls and in primary interstitial COPD lung fibroblasts. In contrast, FGF10 expression was increased in large pulmonary vessels in COPD lungs. Consequently, we identified impaired FGF10 signalling in alveolar walls as an integral part of the pathomechanism that leads to emphysema and PH development: mice with impaired FGF10 signalling (Fgf10+/- and Fgfr2b+/- ) spontaneously developed lung emphysema, PH and other typical pathomechanistic features that generally arise in response to cigarette smoke exposure. CONCLUSION: In a therapeutic approach, FGF10 overexpression successfully restored lung alveolar and vascular structure in mice with established cigarette smoke- and elastase-induced emphysema and PH. FGF10 treatment triggered an initial increase in the number of alveolar type 2 cells that gradually returned to the basal level when the FGF10-mediated repair process progressed. Therefore, the application of recombinant FGF10 or stimulation of the downstream signalling cascade might represent a novel therapeutic strategy in the future.

GLI1+ cells are a source of repair-supportive mesenchymal cells (RSMCs) during airway epithelial regeneration.

Repair-supportive mesenchymal cells (RSMCs) have been recently reported in the context of naphthalene (NA)-induced airway injury and regeneration. These cells transiently express smooth muscle actin (Acta2) and are enriched with platelet-derived growth factor receptor alpha (Pdgfra) and fibroblast growth factor 10 (Fgf10) expression. Genetic deletion of Ctnnb1 (gene coding for beta catenin) or Fgf10 in these cells using the Acta2-Cre-ERT2 driver line after injury (defined as NA-Tam condition; Tam refers to tamoxifen) led to impaired repair of the airway epithelium. In this study, we demonstrate that RSMCs are mostly captured using the Acta2-Cre-ERT2 driver when labeling occurs after (NA-Tam condition) rather than before injury (Tam-NA condition), and that their expansion occurs mostly between days 3 and 7 following NA treatment. Previous studies have shown that lineage-traced peribronchial GLI1+ cells are transiently amplified after NA injury. Here, we report that Gli1 expression is enriched in RSMCs. Using lineage tracing with Gli1Cre-ERT2 mice combined with genetic inactivation of Fgf10, we show that GLI1+ cells with Fgf10 deletion fail to amplify around the injured airways, thus resulting in impaired airway epithelial repair. Interestingly, Fgf10 expression is not upregulated in GLI1+ cells following NA treatment, suggesting that epithelial repair is mostly due to the increased number of Fgf10-expressing GLI1+ cells. Co-culture of SCGB1A1+ cells with GLI1+ cells isolated from non-injured or injured lungs showed that GLI1+ cells from these two conditions are similarly capable of supporting bronchiolar organoid (or bronchiolosphere) formation. Single-cell RNA sequencing on sorted lineage-labeled cells showed that the RSMC signature resembles that of alveolar fibroblasts. Altogether, our study provides strong evidence for the involvement of mesenchymal progenitors in airway epithelial regeneration and highlights the critical role played by Fgf10-expressing GLI1+ cells in this context.

Investigating significant health trends in progressive fibrosing interstitial lung disease (INSIGHTS-ILD): rationale, aims and design of a nationwide prospective registry.

BACKGROUND: The progressive course of pulmonary fibrosis (PPF) is observed with variable prevalence in different entities of fibrosing interstitial lung disease (fILD). PPF is characterised by worsening respiratory symptoms, declining lung function and increasing extent of fibrosis on high-resolution computer tomography. In Germany, data are limited on the characteristics and management of such patients. METHODS/DESIGN: INSIGHTS-ILD is a prospective observational longitudinal registry designed to describe characteristics, management and course of newly diagnosed (incident) and prevalent patients with fILD on the long term. The registry uses a non-probability sampling approach to collect data on characteristics, therapeutic interventions, health-related quality of life and health economic parameters. It is planned to include 900 patients in ambulatory care in about 30 expert sites over three years. The study has been initiated in December 2021, and currently (January 2023) follows 360 patients. DISCUSSION: The registry is expected to provide much-needed data on the characteristics, management, and trajectories of patients fILD in Germany. The start of the study comes at a time when new treatment options are available for PPF. We hypothesize that PPF represents a broad clinical phenotype that is differentially influenced by inflammatory and fibrotic pathomechanisms that need to be treated with anti-inflammatory and/or anti-fibrotic treatment strategies. This registry will allow comparisons with other countries. Gap analyses based on current guidelines for management of these patients will be possible. Trial registration DRKS00027389 (registered on 7.12.2021), BfArM NIS 7562.

A typology of nurses' interaction with relatives in emergency situations.

BACKGROUND: In nursing homes, residents' relatives represent important sources of support for nurses. However, in the heightened stress of emergency situations, interaction between nurses and relatives can raise ethical challenges. RESEARCH OBJECTIVES: The present analysis aimed at elaborating a typology of nurses' experience of ethical support and challenges in their interaction with relatives in emergency situations. RESEARCH DESIGN: Thirty-three semi-structured interviews and six focus groups were conducted with nurses from different nursing homes in Germany. Data were analysed according to Mayring's method of qualitative content analysis. PARTICIPANTS AND RESEARCH CONTEXT: Participants were licensed nurses working in nursing homes. ETHICAL CONSIDERATIONS: Ethical approval was granted by Ostfalia University of Applied Sciences (02.07.2020) and the Ethics Committee of Hannover Medical School (Nr. 8866_BO_K_2020; 27.01.2020). Interviewees were anonymised and focus group were pseudonymised during transcription. All participants provided written consent. FINDINGS/RESULTS: In emergency situations, relatives can represent important sources of support for nurses. However, they may also give rise to different challenges, relating to four ethical conflicts: (1) the challenge of meeting the information needs of relatives while providing appropriate care to all residents; (2) the challenge of managing relatives' demands for hospitalisation when hospitalisation is not deemed necessary by nurses; (3) the challenge of managing relatives' demands for lifesaving treatment when such treatment contradicts the will of the resident; and (4) the challenge of attempting to initiate hospitalisation when relatives oppose this course of action. Several external factors make these conflicts especially challenging for nurses: fear of legal consequences, a low staffing ratio, and a lack of qualified nursing staff. CONCLUSIONS: Conflict between nurses and relatives typically revolves around hospitalisation and the initiation of lifesaving treatment. Whether nurses perceive interaction with relatives as supportive or conflictual essentially depends on the quality of the relationship, which may be negatively influenced by a number of external factors.

Epigenetic Regulation by Suv4-20h1 in Cardiopulmonary Progenitor Cells Is Required to Prevent Pulmonary Hypertension and Chronic Obstructive Pulmonary Disease.

BACKGROUND: The pathogenesis of life-threatening cardiopulmonary diseases such as pulmonary hypertension (PH) and chronic obstructive pulmonary disease (COPD) originates from a complex interplay of environmental factors and genetic predispositions that is not fully understood. Likewise, little is known about developmental abnormalities or epigenetic dysregulations that might predispose for PH or COPD in adult individuals. METHODS: To identify pathology-associated epigenetic alteration in diseased lung tissues, we screened a cohort of human patients with PH and COPD for changes of histone modifications by immunofluorescence staining. To analyze the function of H4K20me2/3 in lung pathogenesis, we developed a series of Suv4-20h1 knockout mouse lines targeting cardiopulmonary progenitor cells and different heart and lung cell types, followed by hemodynamic studies and morphometric assessment of tissue samples. Molecular, cellular, and biochemical techniques were applied to analyze the function of Suv4-20h1-dependent epigenetic processes in cardiopulmonary progenitor cells and their derivatives. RESULTS: We discovered a strong reduction of the histone modifications of H4K20me2/3 in human patients with COPD but not patients with PH that depend on the activity of the H4K20 di-methyltransferase SUV4-20H1. Loss of Suv4-20h1 in cardiopulmonary progenitor cells caused a COPD-like/PH phenotype in mice including the formation of perivascular tertiary lymphoid tissue and goblet cell hyperplasia, hyperproliferation of smooth muscle cells/myofibroblasts, impaired alveolarization and maturation defects of the microvasculature leading to massive right ventricular dilatation and premature death. Mechanistically, SUV4-20H1 binds directly to the 5'-upstream regulatory element of the superoxide dismutase 3 (Sod3) gene to repress its expression. Increased levels of the extracellular SOD3 enzyme in Suv4-20h1 mutants increases hydrogen peroxide concentrations, causing vascular defects and impairing alveolarization. CONCLUSIONS: Our findings reveal a pivotal role of the histone modifier SUV4-20H1 in cardiopulmonary codevelopment and uncover the developmental origins of cardiopulmonary diseases. We assume that the study will facilitate the understanding of pathogenic events causing PH and COPD and aid the development of epigenetic drugs for the treatment of cardiopulmonary diseases.

Addressing Today's Absorption, Distribution, Metabolism, and Excretion (ADME) Challenges in the Translation of In Vitro ADME Characteristics to Humans: A Case Study of the SMN2 mRNA Splicing Modifier Risdiplam.

Small molecules that present complex absorption, distribution, metabolism, and elimination (ADME) properties can be challenging to investigate as potential therapeutics. Acquiring data through standard methods can yield results that are insufficient to describe the in vivo situation, which can affect downstream development decisions. Implementing in vitro-in vivo-in silico strategies throughout the drug development process is effective in identifying and mitigating risks while speeding up their development. Risdiplam (Evrysdi)-an orally bioavailable, small molecule approved by the US Food and Drug Administration and more recently by the European Medicines Agency for the treatment of patients ≥2 months of age with spinal muscular atrophy-is presented here as a case study. Risdiplam is a low-turnover compound whose metabolism is mediated through a non-cytochrome P450 enzymatic pathway. Four main challenges of risdiplam are discussed: predicting in vivo hepatic clearance, determining in vitro metabolites with regard to metabolites in safety testing guidelines, elucidating enzymes responsible for clearance, and estimating potential drug-drug interactions. A combination of in vitro and in vivo results was successfully extrapolated and used to develop a robust physiologically based pharmacokinetic model of risdiplam. These results were verified through early clinical studies, further strengthening the understanding of the ADME properties of risdiplam in humans. These approaches can be applied to other compounds with similar ADME profiles, which may be difficult to investigate using standard methods. SIGNIFICANCE STATEMENT: Risdiplam is the first approved, small-molecule, survival of motor neuron 2 mRNA splicing modifier for the treatment of spinal muscular atrophy. The approach taken to characterize the absorption, distribution, metabolism, and excretion (ADME) properties of risdiplam during clinical development incorporated in vitro-in vivo-in silico techniques, which may be applicable to other small molecules with challenging ADME. These strategies may be useful in improving the speed at which future drug molecules can be developed.

Effect of mild or moderate hepatic impairment on the pharmacokinetics of risdiplam.

AIM: This phase I, multicentre, open-label, nonrandomised, parallel-group, two-part study aimed to evaluate the effect of mild to moderate hepatic impairment on the pharmacokinetics (PK), safety and tolerability of a single oral dose of risdiplam. METHODS: Adult subjects (aged 18-70 years) with mild (Child-Pugh Class A; Part 1) or moderate (Child-Pugh Class B; Part 2) hepatic impairment were matched with subjects with normal hepatic function on sex, age, body mass index and smoking status. Each subject received a single oral dose of 5 mg of risdiplam. Plasma concentrations of risdiplam and its metabolite M1 were measured and PK parameters were compared. Adverse events, laboratory abnormalities, vital signs and electrocardiogram measurements were assessed. RESULTS: After a single dose (5 mg) of risdiplam, the risdiplam PK parameters area under the plasma concentration-time curve from time zero to infinity and maximum observed plasma concentration were approximately 20% and 5% lower, respectively, in subjects with mild hepatic impairment and approximately 8% and 20% higher, respectively, in subjects with moderate hepatic impairment compared with subjects with normal hepatic function. These differences were not statistically significant; all 90% confidence intervals for geometric least squares-means ratios spanned unity. No new risdiplam-related safety findings were observed in subjects with mild or moderate hepatic impairment. CONCLUSION: Mild or moderate hepatic impairment did not have a clinically relevant impact on the PK of risdiplam. Therefore, no dose adjustment is required in patients with mild or moderate hepatic impairment when receiving risdiplam.