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Alveolar type 2 (AT2) cells maintain lung health by acting as stem cells and producing pulmonary surfactant. AT2 dysfunction underlies many lung diseases, including interstitial lung disease (ILD), in which some inherited forms result from the mislocalization of surfactant protein C (SFTPC) variants. Lung disease modeling and dissection of the underlying mechanisms remain challenging due to complexities in deriving and maintaining human AT2 cells ex vivo. Here, we describe the development of mature, expandable AT2 organoids derived from human fetal lungs which are phenotypically stable, can differentiate into AT1-like cells, and are genetically manipulable. We use these organoids to test key effectors of SFTPC maturation identified in a forward genetic screen including the E3 ligase ITCH, demonstrating that their depletion phenocopies the pathological SFTPC redistribution seen for the SFTPC-I73T variant. In summary, we demonstrate the development of a novel alveolar organoid model and use it to identify effectors of SFTPC maturation necessary for AT2 health., Competing Interests: Disclosure and competing interests statement. SAT is a remunerated member of the scientific advisory boards of Qiagen, Foresite Labs, and Element Biosciences, a co-founder and equity holder of TransitionBio, and a part-time employee of GlaxoSmithKline since January 2024. JCM has been an employee of Genentech, Inc. since September 2022. The remaining authors declare no competing interests., (© 2025. The Author(s).)

Aims: Heart failure and associated cachexia is an unresolved and important problem. This study aimed to determine the factors that contribute to cardiac cachexia in a new model of heart failure in mice that lack the integrated stress response (ISR) induced eIF2α phosphatase, PPP1R15A., Methods and Results: Mice were irradiated and reconstituted with bone marrow cells. Mice lacking functional PPP1R15A, exhibited dilated cardiomyopathy and severe weight loss following irradiation, whilst wild-type mice were unaffected. This was associated with increased expression of Gdf15 in the heart and increased levels of GDF15 in circulation. We provide evidence that the blockade of GDF15 activity prevents cachexia and slows the progression of heart failure. We also show the relevance of GDF15 to lean mass and protein intake in patients with heart failure., Conclusion: Our data suggest that cardiac stress mediates a GDF15-dependent pathway that drives weight loss and worsens cardiac function. Blockade of GDF15 could constitute a novel therapeutic option to limit cardiac cachexia and improve clinical outcomes in patients with severe systolic heart failure., Competing Interests: Conflict of interest: S.O.R. is an employee of the University of Cambridge and has provided remunerated consultancy services to the following pharmaceutical companies with an active or potential interest in GDF15: Pfizer, AstraZeneca, MedImmune, and Novo-Nordisk. A.A.V. and J.T received consultancy fees and research support from Roche Diagnostics. The employer of AAV received consultancy fees and/or research support from AnaCardio, AstraZeneca, BMS, Boehringer Ingelheim, Bayer, Corteria, EliLilly, Moderna, Novartis, NovoNordisk, Roche Diagnostics., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Introduction: Spontaneous pneumothorax recurs in 30-54% of patients without surgery. Identifying individuals likely to suffer a recurrence, who might benefit from pre-emptive surgery, is challenging. Previous meta-analysis suggested a relationship between contralateral recurrence and specific CT findings., Methods: We analysed CT images and recurrence rates of 243 patients seen by our tertiary referral pneumothorax service., Results: We validated the meta-analysis observation that contralateral lung cysts are associated with a higher risk of contralateral recurrence in younger individuals. Furthermore, we observed that the size of contralateral cysts to be associated with increased contralateral recurrence in younger patients., Conclusion: The detection of contralateral lung cysts might therefore help identify younger patients more likely to benefit from pre-emptive surgery., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Association of Physicians.)

Pulmonary arterial hypertension (PAH) is a disorder with a large genetic component. Biallelic mutations of EIF2AK4, which encodes the kinase GCN2, are causal in two ultra-rare subtypes of PAH, pulmonary veno-occlusive disease and pulmonary capillary haemangiomatosis. EIF2AK4 variants of unknown significance have also been identified in patients with classical PAH, though their relationship to disease remains unclear. To provide patients with diagnostic information and enable family testing, the functional consequences of such rare variants must be determined, but existing computational methods are imperfect. We applied a suite of bioinformatic and experimental approaches to sixteen EIF2AK4 variants that had been identified in patients. By experimentally testing the functional integrity of the integrated stress response (ISR) downstream of GCN2, we determined that existing computational tools have insufficient sensitivity to reliably predict impaired kinase function. We determined experimentally that several EIF2AK4 variants identified in patients with classical PAH had preserved function and are therefore likely to be non-pathogenic. The dysfunctional variants of GCN2 that we identified could be subclassified into three groups: misfolded, kinase-dead, and hypomorphic. Intriguingly, members of the hypomorphic group were amenable to paradoxical activation by a type-1½ GCN2 kinase inhibitor. This experiment approach may aid in the clinical stratification of EIF2AK4 variants and potentially identify hypomorophic alleles receptive to pharmacological activation., (© The Author(s) 2024. Published by Oxford University Press.)

Most patients with pleural mesothelioma (PM) present with symptomatic pleural effusion. In some patients, PM is only detectable on the pleural surfaces, providing a strong rationale for intrapleural anticancer therapy. In modern prospective studies involving expert radiological staging and specialist multidisciplinary teams, the population incidence of stage I PM (an approximate surrogate of pleura-only PM) is higher than in historical retrospective series. In this Viewpoint, we advocate for the expansion of intrapleural trials to serve these patients, given the paucity of data supporting licensed systemic therapies in this setting and the uncertainties involved in surgical therapy. We begin by reviewing the unique anatomical and physiological features of the PM-bearing pleural space, before critically appraising the evidence for systemic therapies in stage I PM and previous intrapleural PM trials. We conclude with a summary of key challenges and potential solutions, including optimal trial designs, repurposing of indwelling pleural catheters, and new technologies., Competing Interests: Declaration of interests KGB declares institutional grant funding from Rocket Medical and RS Oncology; lecture honoraria from Bristol-Myers Squibb; and the role of chief investigator of the PREDICT-Meso International Accelerator Network. PSA declares research funding from ATARA Biotherapeutics; patents, royalties, and intellectual property on therapies licensed to ATARA Biotherapeutics; and scientific advisory board membership and consulting fees from ATARA Biotherapeutics, Bayer, Bio4T2, Carisma Therapeutics, Imugene, ImmPactBio, Johnson & Johnson, Orion Pharma, and Outpace Bio. PA declares equipment loans for courses from Novatech, Wolf, and Olympus. LD declares lecture honoraria from Bristol-Myers Squibb. YCGL declares receipt of equipment from Rocket Medical for use in clinical trials. ASM declares institutional grant funding from Novartis and Verily; consulting fees from Rising Tide and TRIPTYCH Health Partners; institutional payments or honoraria from Janssen, BeiGene, Chugai Pharmaceutical (Roche), Ideology Health (formerly Health Media), Antoni van Leeuwenhoek Kanker Instituut, AXIS Medical Education, Johnson & Johnson Global Services, Intellisphere, Answers in CME, University of Miami International Mesothelioma Symposium, and Immunocore; support for attending meetings from Shanghai Roche; membership of scientific advisory boards for AbbVie, AstraZeneca, Bristol-Myers Squibb, Genentech/Roche, Takeda Oncology, and Sanofi Genzyme; and study funding from Bristol-Myers Squibb. SJM is co-principal investigator of the Engineering and Physical Sciences Research Council Interdisciplinary Research Collaboration in Targeted Delivery for Hard-to-Treat Cancers; he declares consulting fees from DefiniGEN, and support for attending meetings from Alpha-1 Foundation, Federation of American Societies for Experimental Biology, and Mesothelioma UK. NM declares consulting fees from Rocket Medical UK, Cook Medical UK, and Becton Dickinson. VP declares grant funding from the Danish Comprehensive Cancer Center and no conflicts of interest within the scope of this Viewpoint. NMR declares consulting fees from Rocket Medical UK, Cook Medical UK, and LTI USA. MGZ declares institutional grant funding from Medimmune, Precog, GSK, Epizyme, Polaris, Sellas Life Sciences, Bristol-Myers Squibb, Millenium, Curis, and Atara; consulting fees from Curis, Ikena, Takeda, GSK, and Novocure; and honoraria from PER and Medscape. DS declares support including research funding and consulting fees from AstraZeneca, Boehringer Ingelheim, Exigo Management, Flame Biosciences, HitchBio, Intuitive Surgical, Janssen, Johnson & Johnson, Medscape, Olympus Corporation of the Americas (also known as Spiration), Sensei Biotherapeutics, Trizell, Trustees of the University of Pennsylvania, Verismo, and Wolters Kluwer Health. DAF declares institutional grants from Aldeyra, Astex Therapeutics, Bayer Oncology, Bergen Bio, Boehringer Ingelheim, Clovis Oncology, Eli Lilly, Lovance, MSD, Owkin, Roche Oncology, and RS Oncology; consulting fees from Cambridge Clinical Laboratories and RS Oncology; honoraria from MSD and Bristol-Myers Squibb; support for attending meetings from RS Oncology; and participation on data monitoring or advisory boards for AstraZeneca and RS Oncology. TP declares no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Abstract: For monogenic diseases caused by pathogenic loss-of-function DNA variants, attention focuses on dysregulated gene-specific pathways, usually considering molecular subtypes together within causal genes. To better understand phenotypic variability in hereditary hemorrhagic telangiectasia (HHT), we subcategorized pathogenic DNA variants in ENG/endoglin, ACVRL1/ALK1, and SMAD4 if they generated premature termination codons (PTCs) subject to nonsense-mediated decay. In 3 patient cohorts, a PTC-based classification system explained some previously puzzling hemorrhage variability. In blood outgrowth endothelial cells (BOECs) derived from patients with ACVRL1+/PTC, ENG+/PTC, and SMAD4+/PTC genotypes, PTC-containing RNA transcripts persisted at low levels (8%-23% expected, varying between replicate cultures); genes differentially expressed to Bonferroni P < .05 in HHT+/PTC BOECs clustered significantly only to generic protein terms (isopeptide-bond/ubiquitin-like conjugation) and pulse-chase experiments detected subtle protein maturation differences but no evidence for PTC-truncated protein. BOECs displaying highest PTC persistence were discriminated in unsupervised hierarchical clustering of near-invariant housekeeper genes, with patterns compatible with higher cellular stress in BOECs with >11% PTC persistence. To test directionality, we used a HeLa reporter system to detect induction of activating transcription factor 4 (ATF4), which controls expression of stress-adaptive genes, and showed that ENG Q436X but not ENG R93X directly induced ATF4. AlphaFold accurately modeled relevant ENG domains, with AlphaMissense suggesting that readthrough substitutions would be benign for ENG R93X and other less rare ENG nonsense variants but more damaging for Q436X. We conclude that PTCs should be distinguished from other loss-of-function variants, PTC transcript levels increase in stressed cells, and readthrough proteins and mechanisms provide promising research avenues., (© 2024 American Society of Hematology. Published by Elsevier Inc. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

The development of nanoparticle (NP)-based drug carriers has presented an exciting opportunity to address challenges in oncology. Among the 100,000 available possibilities, zirconium-based metal-organic frameworks (MOFs) have emerged as promising candidates in biomedical applications. Zr-MOFs can be easily synthesized as small-size NPs compatible with intravenous injection, whereas the ease of decorating their external surfaces with functional groups allows for targeted treatment. Despite these benefits, Zr-MOFs suffer degradation and aggregation in real, in vivo conditions, whereas the loaded drugs will suffer the burst effect-i.e., the fast release of drugs in less than 48 h. To tackle these issues, we developed a simple but effective bilayer coating strategy in a generic, two-step process. In this work, bilayer-coated MOF NU-901 remained well dispersed in biologically relevant fluids such as buffers and cell growth media. Additionally, the coating enhances the long-term stability of drug-loaded MOFs in water by simultaneously preventing sustained leakage of the drug and aggregation of the MOF particles. We evaluated our materials for the encapsulation and transport of pemetrexed, the standard-of-care chemotherapy in mesothelioma. The bilayer coating allowed for a slowed release of pemetrexed over 7 days, superior to the typical 48 h release found in bare MOFs. This slow release and the related performance were studied in vitro using both A549 lung cancer and 3T mesothelioma cells. Using high-resolution microscopy, we found the successful uptake of bilayer-coated MOFs by the cells with an accumulation in the lysosomes. The pemetrex-loaded NU-901 was indeed cytotoxic to 3T and A549 cancer cells. Finally, we demonstrated the general approach by extending the coating strategy using two additional lipids and four surfactants. This research highlights how a simple yet effective bilayer coating provides new insights into the design of promising MOF-based drug delivery systems., Competing Interests: The authors declare the following competing financial interest(s): D.F.-J. has commercial interests in Vector Bioscience Cambridge, a spin-out for the commercialization of MOFs in healthcare applications., (© 2024 The Authors. Published by American Chemical Society.)

The pleural lining of the thorax regulates local immunity, inflammation and repair. A variety of conditions, both benign and malignant, including pleural mesothelioma, can affect this tissue. A lack of knowledge concerning the mesothelial and stromal cells comprising the pleura has hampered the development of targeted therapies. Here, we present the first comprehensive single-cell transcriptomic atlas of the human parietal pleura and demonstrate its utility in elucidating pleural biology. We confirm the presence of known universal fibroblasts and describe novel, potentially pleural-specific, fibroblast subtypes. We also present transcriptomic characterisation of multiple in vitro models of benign and malignant mesothelial cells, and characterise these through comparison with in vivo transcriptomic data. While bulk pleural transcriptomes have been reported previously, this is the first study to provide resolution at the single-cell level. We expect our pleural cell atlas will prove invaluable to those studying pleural biology and disease. It has already enabled us to shed light on the transdifferentiation of mesothelial cells, allowing us to develop a simple method for prolonging mesothelial cell differentiation in vitro ., Competing Interests: Conflicts of interest: In addition to the funding acknowledged in the support statement, the following conflicts are declared by the authors. J. Obacz reports grants from Victor Dahdaleh Charitable Foundation. A.S. Coonar reports grants from Innovate UK, consultancy for Viderigen, honoraria for lectures from AstraZeneca, book royalties from Springer Nature, payment for expert testimony from Medicolegal reports, leadership or fiduciary roles for Society for Cardiothoracic Surgery of GB and Ireland, and is Chair of the Thoracic Surgery Committee, NHS, National Clinical Lead for NHS England and a Governor of Royal Papworth Hospital. A. Peryt reports lecture honoraria from AstraZeneca, and travel support from Albyn Medical. N. Kaminski is a scientific founder at Thyron, served as a consultant to Biogen Idec, Boehringer Ingelheim, Third Rock, Pliant, Samumed, NuMedii, Theravance, LifeMax, Three Lake Partners, Optikira, AstraZeneca, RohBar, Veracyte, Augmanity, CSL Behring, Galapagos, Gilead, Chiesi, Arrowhead, Sofinnova and Thyron over the last 3 years, reports Equity in Pliant and Thyron, and grants from Veracyte, Boehringer Ingelheim, BMS and Three Lakes Foundation, and non-financial support from MiRagen and Astra Zeneca; N. Kaminski also has the following patents licensed to biotech: New therapies for IPF, New Therapies for ARDS and New Biomarkers in IPF. M.J. Garnett reports consultancy fees from and equity in Mosaic Therapeutics, and has a patent pending for describing suspension organoid cultures. R.C. Rintoul is chief investigator of Mesobank UK and is part funded by Asthma+Lung UK. The remaining authors have no potential conflicts of interest to disclose., (Copyright ©The authors 2024.)

Adequate lung epithelial repair relies on supportive interactions within the epithelial niche, including interactions with WNT-responsive fibroblasts. In fibroblasts from patients with chronic obstructive pulmonary disease (COPD) or upon in vitro cigarette smoke exposure, Wnt/β-catenin signalling is distorted, which may affect interactions between epithelial cells and fibroblasts resulting in inadequate lung repair. We hypothesized that cigarette smoke (CS), the main risk factor for COPD, interferes with Wnt/β-catenin signalling in fibroblasts through induction of cellular stress responses, including oxidative- and endoplasmic reticulum (ER) stress, and thereby alters epithelial repair support potential. Therefore, we assessed the effect of CS-exposure and the ER stress inducer Thapsigargin (Tg) on Wnt/β-catenin signalling activation in MRC-5 fibroblasts, and on their ability to support lung epithelial organoid formation. Exposure of MRC-5 cells for 15 min with 5 AU/mL CS extract (CSE), and subsequent 6 h incubation induced oxidative stress ( HMOX1 ). Whereas stimulation with 100 nM Tg increased markers of both the integrated stress response (ISR - GADD34 / PPP1R15A , CHOP ) and the unfolded protein response (UPR - XBP1spl , GADD34/PPP1R15A , CHOP and HSPA5/BIP ), CSE only induced GADD34 / PPP1R15A expression. Strikingly, although treatment of MRC-5 cells with the Wnt activator CHIR99021 upregulated the Wnt/β-catenin target gene AXIN2, this response was diminished upon CSE or Tg pre-exposure, which was confirmed using a Wnt-reporter. Furthermore, pre-exposure of MRC-5 cells to CSE or Tg, restricted their ability to support organoid formation upon co-culture with murine pulmonary EpCam + cells in Matrigel at day 14. This restriction was alleviated by pre-treatment with CHIR99021. We conclude that exposure of MRC-5 cells to CSE increases oxidative stress, GADD34/PPP1R15A expression and impairs their ability to support organoid formation. This inhibitory effect may be restored by activating the Wnt/β-catenin signalling pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer GT declared a past co-authorship with the authors RG to the handling Editor, (Copyright © 2023 Khedoe, van Schadewijk, Schwiening, Ng-Blichtfeldt, Marciniak, Stolk, Gosens and Hiemstra.)

Alveolar type 2 (AT2) cells maintain lung health by acting as stem cells and producing pulmonary surfactant 1-3 . AT2 dysfunction underlies many lung diseases including interstitial lung disease (ILD), in which some inherited forms result from mislocalisation of surfactant protein C (SFTPC) variants 4,5 . Disease modelling and dissection of mechanisms remains challenging due to complexities in deriving and maintaining AT2 cells ex vivo. Here, we describe the development of expandable adult AT2-like organoids derived from human fetal lung which are phenotypically stable, can differentiate into AT1-like cells and are genetically manipulable. We use these organoids to test key effectors of SFTPC maturation identified in a forward genetic screen including the E3 ligase ITCH, demonstrating that their depletion phenocopies the pathological SFTPC redistribution seen for the SFTPC-I73T variant. In summary, we demonstrate the development of a novel alveolar organoid model and use it to identify effectors of SFTPC maturation necessary for AT2 health.

The nuclear deubiquitylase BRCA1-associated protein 1 (BAP1) is frequently inactivated in malignant pleural mesothelioma (MPM) and germline BAP1 mutation predisposes to cancers including MPM. To explore the influence on cell physiology and drug sensitivity, we sequentially edited a predisposition mutation (w-) and a promoter trap (KO) into human mesothelial cells. BAP1w-/KO MeT5A cells express less BAP1 protein and phenocopy key aspects of BAP1 loss in MPM. Stable isotope labeling with amino acids in cell culture-mass spectrometry revealed evidence of metabolic adaptation, with concomitant alteration of cellular metabolites. In MeT5A, BAP1 deficiency reduces glycolytic enzyme levels but increases enzymes involved in the tricarboxylic acid cycle and anaplerotic pathways. Notably both argininosuccinate synthase 1 (ASS1), essential for cellular synthesis of arginine, and its substrate aspartate, are elevated in BAP1w-/KO MeT5A cells. Likewise, ASS1 expression is higher in BAP1-altered MPM cell lines, and inversely correlates with BAP1 in The Cancer Genome Atlas MESO dataset. Elevated ASS1 is also evident by IHC staining in epithelioid MPM lacking nuclear BAP1 expression, with improved survival among patients with BAP1-negative/ASS1-expressing tumors. Alterations in arginine metabolism may sensitize cells to metabolic drugs and we find that BAP1-negative/ASS1-expressing MPM cell lines are more sensitive to ASS1 inhibition, although not to inhibition of purine synthesis by mizoribine. Importantly, BAP1w-/KO MeT5A become desensitized to arginine deprivation by pegylated arginine deiminase (ADI-PEG20), phenocopying BAP1-negative/ASS1-expressing MPM cell lines., Implications: Our data reveal an interrelationship between BAP1 and arginine metabolism, providing a potential means of identifying patients with epithelioid MPM likely to benefit from ADI-PEG20., (©2023 The Authors; Published by the American Association for Cancer Research.)

Phase transitions of cellular proteins and lipids play a key role in governing the organisation and coordination of intracellular biology. The frequent juxtaposition of proteinaceous biomolecular condensates to cellular membranes raises the intriguing prospect that phase transitions in proteins and lipids could be co-regulated. Here we investigate this possibility in the ribonucleoprotein (RNP) granule-ANXA11-lysosome ensemble, where ANXA11 tethers RNP granule condensates to lysosomal membranes to enable their co-trafficking. We show that changes to the protein phase state within this system, driven by the low complexity ANXA11 N-terminus, induce a coupled phase state change in the lipids of the underlying membrane. We identify the ANXA11 interacting proteins ALG2 and CALC as potent regulators of ANXA11-based phase coupling and demonstrate their influence on the nanomechanical properties of the ANXA11-lysosome ensemble and its capacity to engage RNP granules. The phenomenon of protein-lipid phase coupling we observe within this system offers an important template to understand the numerous other examples across the cell whereby biomolecular condensates closely juxtapose cell membranes.

Antithrombin, a major endogenous anticoagulant, is a serine protease inhibitor (serpin). We characterized the biological and clinical impact of variants involving C-terminal antithrombin. We performed comprehensive molecular, cellular, and clinical characterization of patients with C-terminal antithrombin variants from a cohort of 444 unrelated individuals with confirmed antithrombin deficiency. We identified 17 patients carrying 12 C-terminal variants, 5 of whom had the p.Arg445Serfs*17 deletion. Five missense variants caused qualitative deficiency, and 7, including 4 insertion-deletion variants, induced severe quantitative deficiency, particularly p.Arg445Serfs*17 (antithrombin <40%). This +1 frameshift variant had a molecular size similar to that of WT antithrombin but possessed a different C-terminus. Morphologic and cotransfection experiments showed that recombinant p.Arg445Serfs*17 was retained at the endoplasmic reticulum and had a dominant-negative effect on WT antithrombin. Characterization of different 1+ frameshift, aberrant C-terminal variants revealed that protein secretion was determined by frameshift site. The introduction of Pro441 in the aberrant C-terminus, shared by 5 efficiently secreted variants, partially rescued p.Arg445Serfs*17 secretion. C-terminal antithrombin mutants have notable heterogeneity, related to variant type and localization. Aberrant C-terminal variants caused by 1+ frameshift, with similar size as WT antithrombin, may be secreted or not, depending on frameshift site. The severe clinical phenotypes of these genetic changes are consistent with their dominant-negative effects.

Objectives: The impulse oscillometry system (IOS) provides an alternative method of lung function testing for patients in whom forced expiratory manoeuvres are contraindicated, such as those with inherited vascular connective tissue disorders. Here we examine the role of IOS in the diagnosis and monitoring of asthma in such patients through a clinical case series and literature review. Methods: The clinical case series comprised of data from 12 patients with inherited connective tissue disorders representing 32 clinical encounters. Of these, 11 encounters were for asthma diagnosis and 21 were for asthma monitoring. Symptoms, exhaled nitric oxide (FeNO) and IOS were assessed at each encounter. Results: In the clinical case series, 5 of 6 patients with likely asthma (as determined by physician review and exhaled nitric oxide testing) had abnormal IOS parameters compared with 0 of 5 of those with unlikely asthma. In the monitoring group, 11 encounters resulted in treatment escalation (demonstrating suboptimal control), and 8 resulted in no change to treatment (good control). Six of 11 of those with suboptimal control had abnormalities in ≥3 IOS parameters, with R5 and R5-20 most frequently affected. Only 1 of 8 of those with good control had abnormalities in ≥3 IOS parameters. Conclusions: IOS can be used as an alternative to conventional lung function testing to support the diagnosis and monitoring of asthma when forced expiratory manoeuvres are contraindicated. Larger studies are required to establish severity and treatment escalation thresholds and provide clearer comparisons with spirometry values.

Competing Interests: All authors are members of the National Institute for Health and Care Research Respiratory Translational Research Collaboration (R-TRC) network. AH has received royalties from Oxford University Press and personal fees from Vertex Pharmaceuticals and Mylan Pharmaceuticals. CB has received research grants from AstraZeneca, GSK, Novartis, Chiesi, Boehringer Ingelheim, Genentech, Roche, Sanofi, Regeneron, Mologics, 4D Pharma, Synairgen, and Merck, and his institution has received payment for his consultancy work from AstraZeneca, GSK, Novartis, Chiesi, Boehringer Ingelheim, Genentech, Roche, Sanofi, Regeneron, Mologics, 4D Pharma, and Synairgen. JD has received personal fees from Vertex Pharmaceuticals, Boehringer Ingelheim, Eloxx, Algipharma, Abbvie, Arcturus, and Enterprise Therapeutics. RD has received research grants from Teva, GSK, Novartis, Sanofi, and Chiesi, and personal fees from Synairgen, Sanofi Genzyme, Galapagos, GSK, AstraZeneca, and Airways Vista; RD reports personal shares in Synairgen. LGH has received research funding from Amgen, AstraZeneca, Medimmune, Janssen, Novartis, Roche, Genentech, GSK, and Boehringer Ingelheim, and personal fees from AstraZeneca, Novartis, Roche, Genentech, GSK, Chiesi, Teva, Boehringer Ingelheim, Theravance, and Vectura. LM has received personal fees from Alexon Pharmaceuticals. JCP has received personal fees from The Limbic, Carrick Therapeutics, and AstraZeneca, and her institution has received research support from Roche. TW has received research grants and contract funding from Synairgen, AstraZeneca, UCB, and Bergenbio, and personal fees from Synairgen, AstraZeneca, and Valneva. LPH has received research grants from Boehringer Ingelheim and Celgene, and her institution has received payment for her consultancy work from DJS Antibodies. TH and SJM declare no competing interests.

Background: The COVID-19 pandemic has presented substantial new challenges to clinical and research teams. Our objective was to analyse the experience of investigators and research delivery staff regarding the research response to COVID-19 in order to identify these challenges as well as solutions for future pandemic planning., Methods: We conducted a survey of diverse research staff involved in delivery of COVID-19 clinical trials across the UK. This was delivered online across centres linked to the NIHR Respiratory Translational Research Collaboration. Responses were analysed using a formal thematic analysis approach to identify common themes and recommendations., Results: 83 survey participants from ten teaching hospitals provided 922 individual question responses. Respondents were involved in a range of research delivery roles but the largest cohort (60%) was study investigators. A wide range of research experiences were captured, including early and late phase trials. Responses were coded into overarching themes. Among common observations, complex protocols without adaptation to a pandemic were noted to have hampered recruitment. Recommendations included the need to develop and test pandemic-specific protocols, and make use of innovations in information technology. Research competition needs to be avoided and drug selection processes should be explicitly transparent., Conclusions: Delivery of clinical trials, particularly earlier phase trials, in a pandemic clinical environment is highly challenging, and was reactive rather than anticipatory. Future pandemic studies should be designed and tested in advance, making use of pragmatic study designs as far as possible and planning for integration between early and later phase trials and regulatory frameworks., Competing Interests: Competing interests: ARH, JD, RD, LGH, TH, SJM, LPM, JP, TW, CEB and LPH are all supported by their respective NIHR Respiratory Biomedical Research Centres. Separate to this work: ARH reports grants from JP Moulton Charity, CF Trust, CF Foundation, MRC and UKRI and personal fees from Vertex Pharmaceuticals and Mylan Pharmaceuticals. JD reports grants from CF Trust, CF Foundation, CF Ireland, EPSRC and personal fees Vertex Pharmaceuticals, Boehringer-Ingelheim, Eloxx, Algipharma, Abbvie, Arcturus, Enterprise Therapeutics. RD reports grants from ERS, Teva, GSK, Novartis, Sanofi, Chiesi and personal fees from Synairgen, Sanofi-Genzyme, Galapagos, GSK, AstraZeneca and Airways Vista, and personal shares in Synairgen. LGH reports grants from MRC, including with multiple industrial partners, and personal fees from Astra Zeneca, Novartis, Roche/Genentech, GlaxoSmithKline, Chiesi, Teva, Theravance and Vectura. SM reports grants from BLF, MRC, June Hancock Mesothelioma Research, Alpha-1 Foundation, and Myrolitis Trust. JP reports grants from UKRI, LifeArc and MRC. TW reports grants from UKRI, Synairgen, AZ, UCB, Bergenbio and personal fees from Synairgen and Valneva. CEB reports fees to his institution from AZ, GSK, Novartis, Chiesi, BI, Genentech, Roche, Sanofi, Regeneron, Mologics, 4DPharma, Synairgen, Merck., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: At least a third of patients go on to suffer a recurrence following a first spontaneous pneumothorax. Surgical intervention reduces the risk of recurrence and has been advocated as a primary treatment for pneumothorax. But surgery exposes patients to the risks of anaesthesia and in some cases can cause chronic pain. Risk stratification of patients to identify those most at risk of recurrence would help direct the most appropriate patients to early intervention. Many studies have addressed the role of thoracic computerized tomography (CT) in identifying those individuals at increased risk of recurrence, but a consensus is lacking., Aim: Our objective was to clarify whether CT provides valuable prognostic information for recurrent pneumothorax., Design: Meta-analysis., Methods: We conducted an exhaustive search of the literature for thoracic CT imaging and pneumothorax, and then performed a meta-analysis using a random effects model to estimate the common odds ratio and standard error., Results: Here, we show by meta-analysis of data from 2475 individuals that emphysematous change on CT scan is associated with a significant increased odds ratio for recurrent pneumothorax ipsilateral to the radiological abnormality (odds ratio 2.49, 95% confidence interval 1.51-4.13)., Conclusions: The association holds true for primary spontaneous pneumothorax when considering emphysematous changes including blebs and bullae. Features, such as bullae at the azygoesophageal recess or increased Goddard score similarly predicted recurrent secondary pneumothorax, as shown by subgroup analysis. Our meta-analysis suggests that CT scanning has value in risk stratifying patients considering surgery for pneumothorax., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Association of Physicians.)

Misfolding of secretory proteins in the endoplasmic reticulum (ER) features in many human diseases. In α 1 -antitrypsin deficiency, the pathogenic Z variant aberrantly assembles into polymers in the hepatocyte ER, leading to cirrhosis. We show that α 1 -antitrypsin polymers undergo a liquid:solid phase transition, forming a protein matrix that retards mobility of ER proteins by size-dependent molecular filtration. The Z-α 1 -antitrypsin phase transition is promoted during ER stress by an ATF6-mediated unfolded protein response. Furthermore, the ER chaperone calreticulin promotes Z-α 1 -antitrypsin solidification and increases protein matrix stiffness. Single-particle tracking reveals that solidification initiates in cells with normal ER morphology, previously assumed to represent a healthy pool. We show that Z-α 1 -antitrypsin-induced hypersensitivity to ER stress can be explained by immobilization of ER chaperones within the polymer matrix. This previously unidentified mechanism of ER dysfunction provides a template for understanding a diverse group of related proteinopathies and identifies ER chaperones as potential therapeutic targets.

The accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress, resulting in activation of the unfolded protein response (UPR) that aims to restore protein homeostasis. However, the UPR also plays an important pathological role in many diseases, including metabolic disorders, cancer and neurological disorders. Over the last decade, significant effort has been invested in targeting signalling proteins involved in the UPR and an array of drug-like molecules is now available. However, these molecules have limitations, the understanding of which is crucial for their development into therapies. Here, we critically review the existing ER stress and UPR-directed drug-like molecules, highlighting both their value and their limitations., (© 2021. Springer Nature Limited.)

Familial spontaneous pneumothorax (FSP) accounts for 10% of primary spontaneous pneumothoraces. Appropriate investigation of FSP enables early diagnosis of serious monogenic diseases and the practice of precision medicine. Here, we show that a pneumothorax genetics multidisciplinary team (MDT) can efficiently diagnose a range of syndromic causes of FSP. A sizeable group (73.6%) of clinically unclassifiable FSPs remains. Using whole genome sequencing we demonstrate that most of these cases are not known monogenic disorders. Therefore, clinico-radiological assessment by an MDT has high sensitivity for currently known clinically important monogenic causes of FSP, which has relevance for the design of efficient pneumothorax services., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)