A novel pathological mutant reveals the role of torsional flexibility in the serpin breach in adoption of an aggregation-prone intermediate

Mutants of alpha-1-antitrypsin cause the protein to self-associate and form ordered aggregates ('polymers') that are retained within hepatocytes, resulting in a predisposition to the development of liver disease. The associated reduction in secretion, and for some mutants, impairment of function, leads to a failure to protect lung tissue against proteases released during the inflammatory response and an increased risk of emphysema. We report here a novel deficiency mutation (Gly192Cys), that we name the Sydney variant, identified in a patient in heterozygosity with the Z allele (Glu342Lys). Cellular analysis revealed that the novel variant was mostly retained as insoluble polymers within the endoplasmic reticulum. The basis for this behaviour was investigated using biophysical and structural techniques. The variant showed a 40% reduction in inhibitory activity and a reduced stability as assessed by thermal unfolding experiments. Polymerisation involves adoption of an aggregation-prone intermediate and paradoxically the energy barrier for transition to this state was increased by 16% for the Gly192Cys variant with respect to the wild-type protein. However, with activation to the intermediate state, polymerisation occurred at a 3.8-fold faster rate overall. X-ray crystallography provided two crystal structures of the Gly192Cys variant, revealing perturbation within the 'breach' region with Cys192 in two different orientations: in one structure it faces towards the hydrophobic core while in the second it is solvent-exposed. This orientational heterogeneity was confirmed by PEGylation. These data show the critical role of the torsional freedom imparted by Gly192 in inhibitory activity and stability against polymerisation.

Native and Ion Mobility Mass Spectrometry Characterization of Alpha 1 Antitrypsin Variants and Oligomers

In this chapter, we describe a method for analyzing both recombinant and plasma-derived alpha 1 antitrypsin and its oligomers by means of native ion mobility mass spectrometry. Our experimental workflow can be applied to other variants of alpha 1 antitrypsin and its oligomers as well as being used to probe their interactions with small molecules in the gas phase.

The under-appreciated world of the serpin family of serine proteinase inhibitors

In the practice of medicine, many fundamental biological pathways that require tight on/off control, such as inflammation and circulatory homeostasis, are regulated by serine proteinases, but we rarely consider the unique protease inhibitors that, in turn, regulate these proteases. The serpins are a family of proteins with a shared tertiary structure, whose members largely act as serine protease inhibitors, found in all forms of life, ranging from viruses, bacteria, and archaea to plants and animals. These proteins represent up to 2-10% of proteins in the human blood and are the third most common protein family.

X chromosome associations with chronic obstructive pulmonary disease and related phenotypes: an X chromosome-wide association study

BACKGROUND

The association between genetic variants on the X chromosome to risk of COPD has not been fully explored. We hypothesize that the X chromosome harbors variants important in determining risk of COPD related phenotypes and may drive sex differences in COPD manifestations.

METHODS

Using X chromosome data from three COPD-enriched cohorts of adult smokers, we performed X chromosome specific quality control, imputation, and testing for association with COPD case-control status, lung function, and quantitative emphysema. Analyses were performed among all subjects, then stratified by sex, and subsequently combined in meta-analyses.

RESULTS

Among 10,193 subjects of non-Hispanic white or European ancestry, a variant near TMSB4X, rs5979771, reached genome-wide significance for association with lung function measured by FEV₁/FVC ([Formula: see text] 0.020, SE 0.004, p 4.97 × 10^-08), with suggestive evidence of association with FEV₁ ([Formula: see text] 0.092, SE 0.018, p 3.40 × 10^-07). Sex-stratified analyses revealed X chromosome variants that were differentially trending in one sex, with significantly different effect sizes or directions.

CONCLUSIONS

This investigation identified loci influencing lung function, COPD, and emphysema in a comprehensive genetic association meta-analysis of X chromosome genetic markers from multiple COPD-related datasets. Sex differences play an important role in the pathobiology of complex lung disease, including X chromosome variants that demonstrate differential effects by sex and variants that may be relevant through escape from X chromosome inactivation. Comprehensive interrogation of the X chromosome to better understand genetic control of COPD and lung function is important to further understanding of disease pathology. Trial registration Genetic Epidemiology of COPD Study (COPDGene) is registered at ClinicalTrials.gov, NCT00608764 (Active since January 28, 2008). Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints Study (ECLIPSE), GlaxoSmithKline study code SCO104960, is registered at ClinicalTrials.gov, NCT00292552 (Active since February 16, 2006). Genetics of COPD in Norway Study (GenKOLS) holds GlaxoSmithKline study code RES11080, Genetics of Chronic Obstructive Lung Disease.

Keratin 8 is a scaffolding and regulatory protein of ERAD complexes

Early recognition and enhanced degradation of misfolded proteins by the endoplasmic reticulum (ER) quality control and ER-associated degradation (ERAD) cause defective protein secretion and membrane targeting, as exemplified for Z-alpha-1-antitrypsin (Z-A1AT), responsible for alpha-1-antitrypsin deficiency (A1ATD) and F508del-CFTR (cystic fibrosis transmembrane conductance regulator) responsible for cystic fibrosis (CF). Prompted by our previous observation that decreasing Keratin 8 (K8) expression increased trafficking of F508del-CFTR to the plasma membrane, we investigated whether K8 impacts trafficking of soluble misfolded Z-A1AT protein. The subsequent goal of this study was to elucidate the mechanism underlying the K8-dependent regulation of protein trafficking, focusing on the ERAD pathway. The results show that diminishing K8 concentration in HeLa cells enhances secretion of both Z-A1AT and wild-type (WT) A1AT with a 13-fold and fourfold increase, respectively. K8 down-regulation triggers ER failure and cellular apoptosis when ER stress is jointly elicited by conditional expression of the µ_s heavy chains, as previously shown for Hrd1 knock-out. Simultaneous K8 silencing and Hrd1 knock-out did not show any synergistic effect, consistent with K8 acting in the Hrd1-governed ERAD step. Fractionation and co-immunoprecipitation experiments reveal that K8 is recruited to ERAD complexes containing Derlin2, Sel1 and Hrd1 proteins upon expression of Z/WT-A1AT and F508del-CFTR. Treatment of the cells with c407, a small molecule inhibiting K8 interaction, decreases K8 and Derlin2 recruitment to high-order ERAD complexes. This was associated with increased Z-A1AT secretion in both HeLa and Z-homozygous A1ATD patients' respiratory cells. Overall, we provide evidence that K8 acts as an ERAD modulator. It may play a scaffolding protein role for early-stage ERAD complexes, regulating Hrd1-governed retrotranslocation initiation/ubiquitination processes. Targeting K8-containing ERAD complexes is an attractive strategy for the pharmacotherapy of A1ATD.

Hepatobiliary phenotypes of adults with alpha-1 antitrypsin deficiency

OBJECTIVE

Alpha-1 antitrypsin deficiency (AATD) is a common, potentially lethal inborn disorder caused by mutations in alpha-1 antitrypsin (AAT). Homozygosity for the 'Pi*Z' variant of AAT (Pi*ZZ genotype) causes lung and liver disease, whereas heterozygous 'Pi*Z' carriage (Pi*MZ genotype) predisposes to gallstones and liver fibrosis. The clinical significance of the more common 'Pi*S' variant remains largely undefined and no robust data exist on the prevalence of liver tumours in AATD.

DESIGN

Baseline phenotypes of AATD individuals and non-carriers were analysed in 482 380 participants in the UK Biobank. 1104 participants of a multinational cohort (586 Pi*ZZ, 239 Pi*SZ, 279 non-carriers) underwent a comprehensive clinical assessment. Associations were adjusted for age, sex, body mass index, diabetes and alcohol consumption.

RESULTS

Among UK Biobank participants, Pi*ZZ individuals displayed the highest liver enzyme values, the highest occurrence of liver fibrosis/cirrhosis (adjusted OR (aOR)=21.7 (8.8-53.7)) and primary liver cancer (aOR=44.5 (10.8-183.6)). Subjects with Pi*MZ genotype had slightly elevated liver enzymes and moderately increased odds for liver fibrosis/cirrhosis (aOR=1.7 (1.2-2.2)) and cholelithiasis (aOR=1.3 (1.2-1.4)). Individuals with homozygous Pi*S mutation (Pi*SS genotype) harboured minimally elevated alanine aminotransferase values, but no other hepatobiliary abnormalities. Pi*SZ participants displayed higher liver enzymes, more frequent liver fibrosis/cirrhosis (aOR=3.1 (1.1-8.2)) and primary liver cancer (aOR=6.6 (1.6-26.9)). The higher fibrosis burden was confirmed in a multinational cohort. Male sex, age ≥50 years, obesity and the presence of diabetes were associated with significant liver fibrosis.

CONCLUSION

Our study defines the hepatobiliary phenotype of individuals with the most relevant AATD genotypes including their predisposition to liver tumours, thereby allowing evidence-based advice and individualised hepatological surveillance.

Genetic variation in genes regulating skeletal muscle regeneration and tissue remodelling associated with weight loss in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death globally. COPD patients with cachexia or weight loss have increased risk of death independent of body mass index (BMI) and lung function. We tested the hypothesis genetic variation is associated with weight loss in COPD using a genome-wide association study approach.

METHODS

Participants with COPD (N = 4308) from three studies (COPDGene, ECLIPSE, and SPIROMICS) were analysed. Discovery analyses were performed in COPDGene with replication in SPIROMICS and ECLIPSE. In COPDGene, weight loss was defined as self-reported unintentional weight loss > 5% in the past year or low BMI (BMI < 20 kg/m2 ). In ECLIPSE and SPIROMICS, weight loss was calculated using available longitudinal visits. Stratified analyses were performed among African American (AA) and Non-Hispanic White (NHW) participants with COPD. Single variant and gene-based analyses were performed adjusting for confounders. Fine mapping was performed using a Bayesian approach integrating genetic association results with linkage disequilibrium and functional annotation. Significant gene networks were identified by integrating genetic regions associated with weight loss with skeletal muscle protein-protein interaction (PPI) data.

RESULTS

At the single variant level, only the rs35368512 variant, intergenic to GRXCR1 and LINC02383, was associated with weight loss (odds ratio = 3.6, 95% confidence interval = 2.3-5.6, P = 3.2 × 10-8 ) among AA COPD participants in COPDGene. At the gene level in COPDGene, EFNA2 and BAIAP2 were significantly associated with weight loss in AA and NHW COPD participants, respectively. The EFNA2 association replicated among AA from SPIROMICS (P = 0.0014), whereas the BAIAP2 association replicated in NHW from ECLIPSE (P = 0.025). The EFNA2 gene encodes the membrane-bound protein ephrin-A2 involved in the regulation of developmental processes and adult tissue homeostasis such as skeletal muscle. The BAIAP2 gene encodes the insulin-responsive protein of mass 53 kD (IRSp53), a negative regulator of myogenic differentiation. Integration of the gene-based findings participants with PPI data revealed networks of genes involved in pathways such as Rho and synapse signalling.

CONCLUSIONS

The EFNA2 and BAIAP2 genes were significantly associated with weight loss in COPD participants. Collectively, the integrative network analyses indicated genetic variation associated with weight loss in COPD may influence skeletal muscle regeneration and tissue remodelling.

Quantitative 18F-fluorodeoxyglucose positron emission tomography/computed tomography to assess pulmonary inflammation in COPD

Rationale

COPD and smoking are characterised by pulmonary inflammation. ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging may improve knowledge of pulmonary inflammation in COPD patients and aid early development of novel therapies as an imaging biomarker.

Objectives

To evaluate pulmonary inflammation, assessed by FDG uptake, in whole and regional lung in “usual” (smoking-related) COPD patients, alpha-1 antitrypsin deficiency (α₁ATD) COPD patients, smokers without COPD and never-smokers using FDG PET/CT. Secondly, to explore cross-sectional associations between FDG PET/CT and systemic inflammatory markers in COPD patients and repeatability of the technique in COPD patients.

Methods

Data from two imaging studies were evaluated. Pulmonary FDG uptake (normalised K_i; nK_i) was measured by Patlak graphical analysis in four subject groups: 84 COPD patients, 11 α₁ATD-COPD patients, 12 smokers and 10 never-smokers. Within the COPD group, associations between nK_i and systemic markers of inflammation were assessed. Repeatability was evaluated in 32 COPD patients comparing nK_i values at baseline and at 4-month follow-up.

Results

COPD patients, α₁ATD-COPD patients and smokers had increased whole lung FDG uptake (nK_i) compared with never-smokers (0.0037±0.001, 0.0040±0.001, 0.0040±0.001 versus 0.0028±0.001 mL·cm⁻³·min⁻¹, respectively, p<0.05 for all). Similar results were observed in upper and middle lung regions. In COPD participants, plasma fibrinogen was associated with whole lung nK_i (β=0.30, p=0.02) in multivariate analysis adjusted for current smoking, forced expiratory volume in 1 s % predicted, systemic neutrophils and C-reactive protein levels. Mean percentage difference in nK_i between the baseline and follow-up was 3.2%, and the within subject coefficient of variability was 7.7%.

Conclusions

FDG PET/CT has potential as a noninvasive tool to enable whole lung and regional quantification of FDG uptake to assess smoking- and COPD-related pulmonary inflammation.

FDG PET/CT has potential utility to noninvasively evaluate pulmonary inflammation in COPD. Pulmonary FDG uptake is increased in COPD patients, positively associated with systemic inflammatory markers and shows low inter-occasion variability.https://bit.ly/3dELYAW

The development of highly potent and selective small molecule correctors of Z α1-antitrypsin misfolding

α1-antitrypsin deficiency is characterised by the misfolding and intracellular polymerisation of mutant α1-antitrypsin protein within the endoplasmic reticulum (ER) of hepatocytes. Small molecules that bind and stabilise Z α1-antitrypsin were identified via a DNA-encoded library screen. A subsequent structure based optimisation led to a series of highly potent, selective and cellular active α1-antitrypsin correctors.

The Importance of N186 in the Alpha-1-Antitrypsin Shutter Region Is Revealed by the Novel Bologna Deficiency Variant

Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.

Scaling Concepts in Serpin Polymer Physics

α1-Antitrypsin is a protease inhibitor belonging to the serpin family. Serpin polymerisation is at the core of a class of genetic conformational diseases called serpinopathies. These polymers are known to be unbranched, flexible, and heterogeneous in size with a beads-on-a-string appearance viewed by negative stain electron microscopy. Here, we use atomic force microscopy and time-lapse dynamic light scattering to measure polymer size and shape for wild-type (M) and Glu342→Lys (Z) α1-antitrypsin, the most common variant that leads to severe pathological deficiency. Our data for small polymers deposited onto mica and in solution reveal a power law relation between the polymer size, namely the end-to-end distance or the hydrodynamic radius, and the polymer mass, proportional to the contour length. We use the scaling concepts of polymer physics to assess that α1-antitrypsin polymers are random linear chains with a low persistence length.

Risk of Exacerbation and Pneumonia with Single-Inhaler Triple versus Dual Therapy in IMPACT

Rationale: In the IMPACT (Informing the Pathway of COPD Treatment) trial, single-inhaler fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) triple therapy reduced exacerbation risk versus FF/VI and UMEC/VI and mortality risk versus UMEC/VI. However, pneumonia incidence was higher in the inhaled corticosteroid (FF)-containing arms, raising questions about the relative benefit of exacerbation reduction compared with the increased risk of pneumonia.Objectives: Determine benefit-risk of the three treatments by evaluating time-to-first and rates of composite exacerbation or pneumonia outcomes.Methods: We evaluated time-to-first (prespecified) and rates (post hoc) of investigator-reported pneumonia, serious pneumonia leading to hospitalization or death, and the composite endpoints of 1) moderate (required antibiotics/corticosteroids)/severe (hospitalized) exacerbation or pneumonia and 2) severe exacerbation or serious (hospitalized) pneumonia. Analyses were repeated for radiographically confirmed pneumonia (post hoc).Results: Moderate/severe exacerbations occurred in 47%, 49%, and 50% of patients randomized to FF/UMEC/VI, FF/VI and UMEC/VI, and pneumonias in 8%, 7%, and 5%, respectively. FF/UMEC/VI reduced the risk of combined moderate/severe exacerbation or pneumonia (time-to-first) versus FF/VI (hazard ratio, 0.87 [95% confidence interval (CI), 0.82-0.92]) and UMEC/VI (0.87 [0.81-0.94]), as well as the risk of combined severe exacerbation or serious pneumonia versus UMEC/VI (0.83 [0.72-0.96]). FF/UMEC/VI reduced the rate of combined moderate/severe exacerbation or pneumonia (rate ratio, 0.78 [0.72-0.84]) and combined severe exacerbation or serious pneumonia (rate ratio, 0.76 [0.65-0.89]) versus UMEC/VI. Results were similar for radiographically confirmed pneumonia endpoints.Conclusions: Despite higher incidence of pneumonia in FF-containing arms, these composite exacerbation/pneumonia outcomes support a favorable benefit-risk profile of FF/UMEC/VI versus FF/VI and UMEC/VI in patients with symptomatic chronic obstructive pulmonary disease and a history of exacerbations.

The molecular species responsible for α1 -antitrypsin deficiency are suppressed by a small molecule chaperone

The formation of ordered Z (Glu342Lys) α1 -antitrypsin polymers in hepatocytes is central to liver disease in α1 -antitrypsin deficiency. In vitro experiments have identified an intermediate conformational state (M*) that precedes polymer formation, but this has yet to be identified in vivo. Moreover, the mechanism of polymer formation and their fate in cells have been incompletely characterised. We have used cell models of disease in conjunction with conformation-selective monoclonal antibodies and a small molecule inhibitor of polymerisation to define the dynamics of polymer formation, accumulation and secretion. Pulse-chase experiments demonstrate that Z α1 -antitrypsin accumulates as short-chain polymers that partition with soluble cellular components and are partially secreted by cells. These precede the formation of larger, insoluble polymers with a longer half-life (10.9 ± 1.7 h and 20.9 ± 7.4 h for soluble and insoluble polymers, respectively). The M* intermediate (or a by-product thereof) was identified in the cells by a conformation-specific monoclonal antibody. This was completely abrogated by treatment with the small molecule, which also blocked the formation of intracellular polymers. These data allow us to conclude that the M* conformation is central to polymerisation of Z α1 -antitrypsin in vivo; preventing its accumulation represents a tractable approach for pharmacological treatment of this condition; polymers are partially secreted; and polymers exist as two distinct populations in cells whose different dynamics have likely consequences for the aetiology of the disease.

Markers of disease activity in COPD: an 8-year mortality study in the ECLIPSE cohort

Rationale

There are no validated measures of disease activity in COPD. Since “active” disease is expected to have worse outcomes (e.g. mortality), we explored potential markers of disease activity in patients enrolled in the ECLIPSE cohort in relation to 8-year all-cause mortality.

Methods

We investigated 1) how changes in relevant clinical variables over time (1 or 3 years) relate to 8-year mortality; 2) whether these variables inter-relate; and 3) if any clinical, imaging and/or biological marker measured cross-sectionally at baseline relates to any activity component.

Results

Results showed that 1) after 1 year, hospitalisation for COPD, exacerbation frequency, worsening of body mass index, airflow obstruction, dyspnoea and exercise (BODE) index or health status (St George's Respiratory Questionnaire (SGRQ)) and persistence of systemic inflammation were significantly associated with 8-year mortality; 2) at 3 years, the same markers, plus forced expiratory volume in 1 s (FEV₁) decline and to a lesser degree computed tomography (CT) emphysema, showed association, thus qualifying as markers of disease activity; 3) changes in FEV₁, inflammatory cytokines and CT emphysema were not inter-related, while the multidimensional indices (BODE and SGRQ) showed modest correlations; and 4) changes in these markers could not be predicted by any baseline cross-sectional measure.

Conclusions

In COPD, 1- and 3-year changes in exacerbation frequency, systemic inflammation, BODE and SGRQ scores and FEV₁ decline are independent markers of disease activity associated with 8-year all-cause mortality. These disease activity markers are generally independent and not predictable from baseline measurements.

In patients with COPD, 1- and 3-year changes in exacerbation frequency, systemic inflammation, BODE and SGRQ scores, and FEV₁ decline, are independent markers of disease activity associated with 8-year all-cause mortalityhttps://bit.ly/2CyifcN

Development of a small molecule that corrects misfolding and increases secretion of Z α1 -antitrypsin

Severe α1 -antitrypsin deficiency results from the Z allele (Glu342Lys) that causes the accumulation of homopolymers of mutant α1 -antitrypsin within the endoplasmic reticulum of hepatocytes in association with liver disease. We have used a DNA-encoded chemical library to undertake a high-throughput screen to identify small molecules that bind to, and stabilise Z α1 -antitrypsin. The lead compound blocks Z α1 -antitrypsin polymerisation in vitro, reduces intracellular polymerisation and increases the secretion of Z α1 -antitrypsin threefold in an iPSC model of disease. Crystallographic and biophysical analyses demonstrate that GSK716 and related molecules bind to a cryptic binding pocket, negate the local effects of the Z mutation and stabilise the bound state against progression along the polymerisation pathway. Oral dosing of transgenic mice at 100 mg/kg three times a day for 20 days increased the secretion of Z α1 -antitrypsin into the plasma by sevenfold. There was no observable clearance of hepatic inclusions with respect to controls over the same time period. This study provides proof of principle that "mutation ameliorating" small molecules can block the aberrant polymerisation that underlies Z α1 -antitrypsin deficiency.

Conversion of the death inhibitor ARC to a killer activates pancreatic β cell death in diabetes

Loss of insulin-secreting pancreatic β cells through apoptosis contributes to the progression of type 2 diabetes, but underlying mechanisms remain elusive. Here, we identify a pathway in which the cell death inhibitor ARC paradoxically becomes a killer during diabetes. While cytoplasmic ARC maintains β cell viability and pancreatic architecture, a pool of ARC relocates to the nucleus to induce β cell apoptosis in humans with diabetes and several pathophysiologically distinct mouse models. β cell death results through the coordinate downregulation of serpins (serine protease inhibitors) not previously known to be synthesized and secreted by β cells. Loss of the serpin α₁-antitrypsin from the extracellular space unleashes elastase, triggering the disruption of β cell anchorage and subsequent cell death. Administration of α₁-antitrypsin to mice with diabetes prevents β cell death and metabolic abnormalities. These data uncover a pathway for β cell loss in type 2 diabetes and identify an FDA-approved drug that may impede progression of this syndrome.

InforMing the PAthway of COPD Treatment (IMPACT Trial) Single-Inhaler Triple Therapy (Fluticasone Furoate/Umeclidinium/Vilanterol) Versus Fluticasone Furoate/Vilanterol and Umeclidinium/Vilanterol in Patients With COPD: Analysis of the Western Europe and North America Regions

BACKGROUND

The InforMing the Pathway of COPD Treatment (IMPACT) trial demonstrated lower moderate/severe exacerbation rates with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI or UMEC/VI in patients with chronic obstructive pulmonary disease (COPD) and a history of exacerbations. Since IMPACT was a global study, post-hoc analyses were conducted by geographic region to investigate potential differences in overall findings.

METHODS

IMPACT was a 52-week, randomized, double-blind trial. Patients with symptomatic COPD and ≥1 moderate/severe exacerbation in the prior year were randomized 2:2:1 to once-daily FF/UMEC/VI 100/62.5/25µg, FF/VI 100/25µg, or UMEC/VI 62.5/25µg. Endpoints assessed in the overall, Western Europe and North America populations included on-treatment moderate/severe exacerbation (rates and time-to-first), trough forced expiratory volume in 1 second and St George's Respiratory Questionnaire (SGRQ) total score. Safety was assessed.

RESULTS

Overall, 10,355 patients were enrolled, 3164 from Western Europe, 2639 from North America. FF/UMEC/VI significantly reduced on-treatment moderate/severe exacerbation rates versus FF/VI and UMEC/VI in Western Europe (rate ratios 0.82 [95%CI 0.74-0.91], P<.001 and 0.76 [0.67-0.87], P<.001) and in North America (0.87 [0.77-0.97], P=.014 and 0.69 [0.60-0.80], P<.001). FF/UMEC/VI reduced time-to-first moderate/severe exacerbation and improved lung function versus FF/VI and UMEC/VI in both regions, and improved SGRQ total score in Western Europe, but not North America. Safety profiles were generally similar between treatment groups/regions; the inhaled corticosteroid class effect of increased pneumonia incidence was seen in North America but not Western Europe.

CONCLUSION

Consistent with intent-to-treat results, FF/UMEC/VI reduced moderate/severe exacerbation rate and risk and improved lung function in Western Europe and North America; however, between-regions differences were seen for SGRQ total score and pneumonia incidence.

CLINICAL TRIAL REGISTRATION

NCT02164513.

Prognostic value of clinically important deterioration in COPD: IMPACT trial analysis

INTRODUCTION

Clinically important deterioration (CID) is a multicomponent measure for assessing disease worsening in chronic obstructive pulmonary disease (COPD). This analysis investigated the prognostic value of a CID event on future clinical outcomes and the effect of single-inhaler triple versus dual therapy on reducing CID risk in patients in the IMPACT trial.

METHODS

IMPACT was a phase III, double-blind, 52-week, multicentre trial. Patients with symptomatic COPD and at least one moderate/severe exacerbation in the prior year were randomised 2:2:1 to fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 µg, FF/VI 100/25 µg or UMEC/VI 62.5/25 µg. CID at the time-point of interest was defined as a moderate/severe exacerbation, ≥100 mL decrease in trough forced expiratory volume in 1 s or deterioration in health status (increase of ≥4.0 units in St George's Respiratory Questionnaire total score or increase of ≥2.0 units in COPD Assessment Test score) from baseline. A treatment-independent post hoc prognostic analysis compared clinical outcomes up to week 52 in patients with/without a CID by week 28. A prospective analysis evaluated time to first CID with each treatment.

RESULTS

Patients with a CID by week 28 had significantly increased exacerbation rates after week 28, smaller improvements in lung function and health status at week 52 (all p<0.001), and increased risk of all-cause mortality after week 28 versus patients who were CID-free. FF/UMEC/VI significantly reduced CID risk versus dual therapies (all p<0.001).

CONCLUSIONS

Prevention of short-term disease worsening was associated with better long-term clinical outcomes. FF/UMEC/VI reduced CID risk versus dual therapies; this effect may improve long-term prognosis in this population.

Non-invasive testing for liver pathology in alpha-1 antitrypsin deficiency

Background

Many patients with alpha-1 antitrypsin deficiency (A1ATD) receive care in respiratory clinics without access to specialist hepatology expertise. Liver disease can develop asymptomatically, and non-invasive markers of fibrosis may help identify patients who require definitive assessment with liver biopsy. We evaluated the utility of non-invasive markers of liver fibrosis in A1ATD to guide testing in settings without ready access to hepatology expertise.

Methods

Patients attending the London A1ATD service undergo assessment using blood tests to calculate the ‘APRI’ and ‘FIB-4’ score, liver ultrasound and Fibroscan. Liver biopsy is offered to patients who have abnormal liver function tests with abnormal liver ultrasound and/or liver stiffness >6 kPa on Fibroscan. Liver biopsies were assessed for the presence of A1AT, steatosis, fibrosis and inflammation.

Results

75 patients with A1ATD had results for analysis, 56% were female, age 16–82 years. 75% of patients had Fibroscan <6 kPa, 19% had Fibroscan 6–7.9 kPa and 6%>8 kPa. There was a significant correlation between FIB-4 and Fibroscan (r=0.244, p=0.035). Fibroscan >6 kPa corresponded to a FIB-4 score of >1.26. However, FIB-4 >1.26 had poor sensitivity (47%), specificity (32%) and positive-predictive value (PPV; 36%) to identify Fibroscan >6 kPa. The negative-predictive value (NPV) was stronger at 81%. APRI data were similar. Twelve patients underwent liver biopsy, with 11 reports available for analysis. Six had FIB-4 scores<1.26 and five had Fibroscan of <6 kPa. A1AT was present in 64% of biopsies, steatosis in 82%, mild fibrosis in 36%, moderate fibrosis in 9% and severe fibrosis in 9%.

Conclusion

A combination of liver ultrasound and non-invasive fibrosis tests can help identify patients with A1ATD liver injury. However, APRI and FIB-4 scores alone had poor sensitivity and specificity to justify use as an independent tool for liver pathology in A1ATD.

High-resolution ex vivo NMR spectroscopy of human Z α1-antitrypsin

Genetic mutations predispose the serine protease inhibitor α1-antitrypsin to misfolding and polymerisation within hepatocytes, causing liver disease and chronic obstructive pulmonary disease. This misfolding occurs via a transiently populated intermediate state, but our structural understanding of this process is limited by the instability of recombinant α1-antitrypsin variants in solution. Here we apply NMR spectroscopy to patient-derived samples of α1-antitrypsin at natural isotopic abundance to investigate the consequences of disease-causing mutations, and observe widespread chemical shift perturbations for methyl groups in Z AAT (E342K). By comparison with perturbations induced by binding of a small-molecule inhibitor of misfolding we conclude that they arise from rapid exchange between the native conformation and a well-populated intermediate state. The observation that this intermediate is stabilised by inhibitor binding suggests a paradoxical approach to the targeted treatment of protein misfolding disorders, wherein the stabilisation of disease-associated states provides selectivity while inhibiting further transitions along misfolding pathways.

The Effect of Inhaled Corticosteroid Withdrawal and Baseline Inhaled Treatment on Exacerbations in the IMPACT Study. A Randomized, Double-Blind, Multicenter Clinical Trial

Rationale: In the IMPACT (Informing the Pathway of Chronic Obstructive Pulmonary Disease Treatment) trial, fluticasone furoate (FF)/umeclidinium (UMEC)/vilanterol (VI) significantly reduced exacerbations compared with FF/VI or UMEC/VI in patients with symptomatic chronic obstructive pulmonary disease and a history of exacerbations.

Objectives: To understand whether inhaled corticosteroid (ICS) withdrawal affected IMPACT results, given direct transition from prior maintenance medication to study medication at randomization.

Methods: Exacerbations and change from baseline in trough FEV₁ and St. George’s Respiratory Questionnaire results were analyzed by prior ICS use. Exacerbations were also analyzed while excluding data from the first 30 days.

Measurements and Main Results: FF/UMEC/VI significantly reduced the annual moderate/severe exacerbation rate compared with UMEC/VI in prior ICS users (29% reduction; P < 0.001), but only a numerical reduction was seen among prior ICS nonusers (12% reduction; P = 0.115). To minimize impact from ICS withdrawal, in an analysis excluding the first 30 days, FF/UMEC/VI continued to significantly reduce the annual on-treatment moderate/severe exacerbation rate (19%; P < 0.001) compared with UMEC/VI. The benefit of FF/UMEC/VI compared with UMEC/VI was seen for severe exacerbation rates, regardless of prior ICS use (prior ICS users, 35% reduction; P < 0.001; non-ICS users, 35% reduction; P = 0.018), and overall when excluding the first 30 days (29%; P < 0.001). Improvements from baseline with FF/UMEC/VI compared with UMEC/VI were also maintained throughout the study for both trough FEV₁ and St. George’s Respiratory Questionnaire, regardless of prior ICS use.

Conclusions: These data support the important treatment effects of FF/UMEC/VI combination therapy on exacerbation reduction, lung function, and quality of life that do not appear to be related to abrupt ICS withdrawal.

Clinical trial registered with www.clinicaltrials.gov (NCT 02164513).

Effect of Age on the Efficacy and Safety of Once-Daily Single-Inhaler Triple-Therapy Fluticasone Furoate/Umeclidinium/Vilanterol in Patients With COPD: A Post Hoc Analysis of the Informing the Pathway of COPD Treatment Trial

BACKGROUND

In the Informing the Pathway of COPD Treatment (IMPACT) trial, single-inhaler triple-therapy fluticasone furoate (FF), umeclidinium (UMEC), and vilanterol (VI) reduced moderate/severe exacerbation rates vs FF/VI and UMEC/VI in patients with symptomatic COPD and a history of exacerbations, with a similar safety profile.

RESEARCH QUESTION

Are trial outcomes with single-inhaler triple-therapy FF/UMEC/VI vs FF/VI and UMEC/VI affected by age in patients with symptomatic COPD and a history of exacerbations?

STUDY DESIGN AND METHODS

IMPACT was a phase III, double-blind, 52-week trial. Patients ≥ 40 years of age with symptomatic COPD and ≥ 1 moderate/severe exacerbation in the previous year were randomly assigned 2:2:1 to FF/UMEC/VI 100/62.5/25 μg, FF/VI 100/25 μg, or UMEC/VI 62.5/25 μg. End points assessed by age included annual rate of moderate/severe exacerbations, change from baseline (CFB) in trough FEV₁, proportion of St. George's Respiratory Questionnaire (SGRQ) responders (≥ 4 units decrease from baseline in SGRQ total score), and safety.

RESULTS

The intention-to-treat population comprised 10,355 patients; 4,724 (46%), 4,225 (41%), and 1,406 (14%) were ≤ 64, 65 to 74, and ≥ 75 years of age, respectively. FF/UMEC/VI reduced on-treatment moderate/severe exacerbation rates vs FF/VI (% reduction [95% CI]: ≤ 64 years, 8% [-1 to 16]; P = .070; 65-74 years, 22% [14-29]; P < .001; ≥ 75 years, 18% [3-31]; P = .021) and vs UMEC/VI (≤ 64 years, 16% [7-25]; P = .002; 65-74 years, 33% [25-41]; P < .001; ≥ 75 years, 24% [6-38]; P = .012), with greatest rate reduction seen in the 65 to 74 and ≥ 75 years subgroups. Post hoc analyses of CFB in trough FEV₁ and proportion of SGRQ responders at week 52 were significantly greater with FF/UMEC/VI than with FF/VI or UMEC/VI in all subgroups. No new safety signals were identified.

INTERPRETATION

FF/UMEC/VI reduced the rate of moderate/severe exacerbations and improved lung function and health status vs FF/VI and UMEC/VI irrespective of age for most end points, with a similar safety profile.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02164513; URL: www.clinicaltrials.govCTT116855.

The structural basis for Z α1-antitrypsin polymerization in the liver

The serpinopathies are among a diverse set of conformational diseases that involve the aberrant self-association of proteins into ordered aggregates. α₁-Antitrypsin deficiency is the archetypal serpinopathy and results from the formation and deposition of mutant forms of α₁-antitrypsin as "polymer" chains in liver tissue. No detailed structural analysis has been performed of this material. Moreover, there is little information on the relevance of well-studied artificially induced polymers to these disease-associated molecules. We have isolated polymers from the liver tissue of Z α₁-antitrypsin homozygotes (E342K) who have undergone transplantation, labeled them using a Fab fragment, and performed single-particle analysis of negative-stain electron micrographs. The data show structural equivalence between heat-induced and ex vivo polymers and that the intersubunit linkage is best explained by a carboxyl-terminal domain swap between molecules of α₁-antitrypsin.

Reduction in All-Cause Mortality with Fluticasone Furoate/Umeclidinium/Vilanterol in Patients with Chronic Obstructive Pulmonary Disease

Rationale: The IMPACT (Informing the Pathway of Chronic Obstructive Pulmonary Disease Treatment) trial demonstrated a significant reduction in all-cause mortality (ACM) risk with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus UMEC/VI in patients with chronic obstructive pulmonary disease (COPD) at risk of future exacerbations. Five hundred seventy-four patients were censored in the original analysis owing to incomplete vital status information.

Objectives: Report ACM and impact of stepping down therapy, following collection of additional vital status data.

Methods: Patients were randomized 2:2:1 to FF/UMEC/VI 100/62.5/25 μg, FF/VI 100/25 μg, or UMEC/VI 62.5/25 μg following a run-in on their COPD therapies. Time to ACM was prespecified. Additional vital status data collection and subsequent analyses were performed post hoc.

Measurements and Main Results: We report vital status data for 99.6% of the intention-to-treat population (n = 10,355), documenting 98 (2.36%) deaths on FF/UMEC/VI, 109 (2.64%) on FF/VI, and 66 (3.19%) on UMEC/VI. For FF/UMEC/VI, the hazard ratio for death was 0.72 (95% confidence interval, 0.53–0.99; P = 0.042) versus UMEC/VI and 0.89 (95% confidence interval, 0.67–1.16; P = 0.387) versus FF/VI. Independent adjudication confirmed lower rates of cardiovascular and respiratory death and death associated with the patient’s COPD.

Conclusions: In this secondary analysis of an efficacy outcome from the IMPACT trial, once-daily single-inhaler FF/UMEC/VI triple therapy reduced the risk of ACM versus UMEC/VI in patients with symptomatic COPD and a history of exacerbations.

Intrahepatic heteropolymerization of M and Z alpha-1-antitrypsin

The α-1-antitrypsin (or alpha-1-antitrypsin, A1AT) Z variant is the primary cause of severe A1AT deficiency and forms polymeric chains that aggregate in the endoplasmic reticulum of hepatocytes. Around 2%-5% of Europeans are heterozygous for the Z and WT M allele, and there is evidence of increased risk of liver disease when compared with MM A1AT individuals. We have shown that Z and M A1AT can copolymerize in cell models, but there has been no direct observation of heteropolymer formation in vivo. To this end, we developed a monoclonal antibody (mAb2H2) that specifically binds to M in preference to Z A1AT, localized its epitope using crystallography to a region perturbed by the Z (Glu342Lys) substitution, and used Fab fragments to label polymers isolated from an MZ heterozygote liver explant. Glu342 is critical to the affinity of mAb2H2, since it also recognized the mild S-deficiency variant (Glu264Val) present in circulating polymers from SZ heterozygotes. Negative-stain electron microscopy of the Fab2H2-labeled liver polymers revealed that M comprises around 6% of the polymer subunits in the MZ liver sample. These data demonstrate that Z A1AT can form heteropolymers with polymerization-inert variants in vivo with implications for liver disease in heterozygous individuals.

Single-inhaler triple therapy fluticasone furoate/umeclidinium/vilanterol versus fluticasone furoate/vilanterol and umeclidinium/vilanterol in patients with COPD: results on cardiovascular safety from the IMPACT trial

Background

This analysis of the IMPACT study assessed the cardiovascular (CV) safety of single-inhaler triple therapy with fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) versus FF/VI and UMEC/VI dual therapy.

Methods

IMPACT was a 52-week, randomized, double-blind, multicenter Phase III study comparing the efficacy and safety of FF/UMEC/VI 100/62.5/25 mcg with FF/VI 100/25 mcg or UMEC/VI 62.5/25 mcg in patients ≥40 years of age with symptomatic chronic obstructive pulmonary disease (COPD) and ≥1 moderate/severe exacerbation in the previous year. The inclusion criteria for the study were intentionally designed to permit the enrollment of patients with significant concurrent CV disease/risk. CV safety assessments included proportion of patients with and exposure-adjusted rates of on-treatment CV adverse events of special interest (CVAESI) and major adverse cardiac events (MACE), as well as time-to-first (TTF) CVAESI, and TTF CVAESI resulting in hospitalization/prolonged hospitalization or death.

Results

Baseline CV risk factors were similar across treatment groups. Overall, 68% of patients (n = 7012) had ≥1 CV risk factor and 40% (n = 4127) had ≥2. At baseline, 29% of patients reported a current/past cardiac disorder and 58% reported a current/past vascular disorder. The proportion of patients with on-treatment CVAESI was 11% for both FF/UMEC/VI and UMEC/VI, and 10% for FF/VI. There was no statistical difference for FF/UMEC/VI versus FF/VI or UMEC/VI in TTF CVAESI (hazard ratio [HR]: 0.98, 95% confidence interval [CI]: 0.85, 1.11; p = 0.711 and HR: 0.92, 95% CI: 0.78, 1.08; p = 0.317, respectively) nor TTF CVAESI leading to hospitalization/prolonged hospitalization or death (HR: 1.19, 95% CI: 0.93, 1.51; p = 0.167 and HR: 0.96, 95% CI: 0.72, 1.27; p = 0.760, respectively). On-treatment MACE occurred in ≤3% of patients across treatment groups, with similar prevalence and rates between treatments.

Conclusions

In a symptomatic COPD population with a history of exacerbations and a high rate of CV disease/risk, the proportion of patients with CVAESI and MACE was 10–11% and 1–3%, respectively, across treatment arms, and the risk of CVAESI was low and similar across treatment arms. There was no statistically significant increased CV risk associated with the use of FF/UMEC/VI versus FF/VI or UMEC/VI, and UMEC/VI versus FF/VI.

Trial registration

NCT02164513 (GSK study number CTT116855).

The effect of exacerbation history on outcomes in the IMPACT trial

IMPACT, a 52-week, randomised, double-blind trial, assessed the efficacy and safety of fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) triple therapy versus FF/VI or UMEC/VI in patients with symptomatic COPD and a history of exacerbations.

Subgroup analyses assessed whether the efficacy of FF/UMEC/VI versus FF/VI or UMEC/VI and UMEC/VI versus FF/VI varies according to prior exacerbation history, and the combined effects of exacerbation history and blood eosinophil counts. Three subgroups were defined: single moderate (1 moderate/no severe; n=3056 (30%)), frequent moderate (≥2 moderate/no severe; n=4628 (45%)) and severe (≥1 severe/any moderate; n=2671 (26%)). End-points included annual on-treatment moderate/severe exacerbation rate (pre-specified), lung function and health status (both post-hoc).

Moderate/severe exacerbation rates (reduction % (95% CI)) were reduced in the FF/UMEC/VI group versus FF/VI (single moderate 20% (10–29), frequent moderate 11% (2–19), severe 17% (7–26)) and versus UMEC/VI (single moderate 18% (5–29), frequent moderate 29% (21–37), severe 26% (14–35)). Moderate/severe exacerbation rates were reduced in the FF/VI group versus UMEC/VI in the frequent moderate subgroup; a numerical reduction was observed in the severe subgroup (single moderate 2% (−12–18), frequent moderate 21% (11–29), severe 11% (−3–22)). Moderate/severe exacerbation rates were lower in the FF/VI group compared with UMEC/VI in patients with higher eosinophil counts. FF/UMEC/VI improved lung function and health status versus both dual therapies irrespective of exacerbation subgroup. UMEC/VI improved lung function versus FF/VI in all subgroups.

Triple therapy was more effective than dual regardless of exacerbation history, consistent with results in the intent-to-treat population. Comparisons between dual therapies were influenced by prior exacerbation history and eosinophil counts.

FF/UMEC/VI shows benefits vs FF/VI and UMEC/VI across multiple endpoints irrespective of exacerbation history. Exacerbation history and eosinophils influenced the comparison between UMEC/VI and FF/VI, and eosinophils that between FF/UMEC/VI and UMEC/VI.http://bit.ly/2SHu2ey

Heme metabolism genes Downregulated in COPD Cachexia

INTRODUCTION

Cachexia contributes to increased mortality and reduced quality of life in Chronic Obstructive Pulmonary Disease (COPD) and may be associated with underlying gene expression changes. Our goal was to identify differential gene expression signatures associated with COPD cachexia in current and former smokers.

METHODS

We analyzed whole-blood gene expression data from participants with COPD in a discovery cohort (COPDGene, N = 400) and assessed replication (ECLIPSE, N = 114). To approximate the consensus definition using available criteria, cachexia was defined as weight-loss > 5% in the past 12 months or low body mass index (BMI) (< 20 kg/m2) and 1/3 criteria: decreased muscle strength (six-minute walk distance < 350 m), anemia (hemoglobin < 12 g/dl), and low fat-free mass index (FFMI) (< 15 kg/m2 among women and < 17 kg/m2 among men) in COPDGene. In ECLIPSE, cachexia was defined as weight-loss > 5% in the past 12 months or low BMI and 3/5 criteria: decreased muscle strength, anorexia, abnormal biochemistry (anemia or high c-reactive protein (> 5 mg/l)), fatigue, and low FFMI. Differential gene expression was assessed between cachectic and non-cachectic subjects, adjusting for age, sex, white blood cell counts, and technical covariates. Gene set enrichment analysis was performed using MSigDB.

RESULTS

The prevalence of COPD cachexia was 13.7% in COPDGene and 7.9% in ECLIPSE. Fourteen genes were differentially downregulated in cachectic versus non-cachectic COPD patients in COPDGene (FDR < 0.05) and ECLIPSE (FDR < 0.05).

DISCUSSION

Several replicated genes regulating heme metabolism were downregulated among participants with COPD cachexia. Impaired heme biosynthesis may contribute to cachexia development through free-iron buildup and oxidative tissue damage.

Common and Rare Variants Genetic Association Analysis of Cigarettes per Day Among Ever-Smokers in Chronic Obstructive Pulmonary Disease Cases and Controls

INTRODUCTION

Cigarette smoking is a major environmental risk factor for many diseases, including chronic obstructive pulmonary disease (COPD). There are shared genetic influences on cigarette smoking and COPD. Genetic risk factors for cigarette smoking in cohorts enriched for COPD are largely unknown.

METHODS

We performed genome-wide association analyses for average cigarettes per day (CPD) across the Genetic Epidemiology of COPD (COPDGene) non-Hispanic white (NHW) (n = 6659) and African American (AA) (n = 3260), GenKOLS (the Genetics of Chronic Obstructive Lung Disease) (n = 1671), and ECLIPSE (the Evaluation of COPD Longitudinally to Identify Predictive Surrogate Endpoints) (n = 1942) cohorts. In addition, we performed exome array association analyses across the COPDGene NHW and AA cohorts. We considered analyses across the entire cohort and stratified by COPD case-control status.

RESULTS

We identified genome-wide significant associations for CPD on chromosome 15q25 across all cohorts (lowest p = 1.78 × 10-15), except in the COPDGene AA cohort alone. Previously reported associations on chromosome 19 had suggestive and directionally consistent associations (RAB4, p = 1.95 × 10-6; CYP2A7, p = 7.50 × 10-5; CYP2B6, p = 4.04 × 10-4). When we stratified by COPD case-control status, single nucleotide polymorphisms on chromosome 15q25 were nominally associated with both NHW COPD cases (β = 0.11, p = 5.58 × 10-4) and controls (β = 0.12, p = 3.86 × 10-5) For the gene-based exome array association analysis of rare variants, there were no exome-wide significant associations. For these previously replicated associations, the most significant results were among COPDGene NHW subjects for CYP2A7 (p = 5.2 × 10-4).

CONCLUSIONS

In a large genome-wide association study of both common variants and a gene-based association of rare coding variants in ever-smokers, we found genome-wide significant associations on chromosome 15q25 with CPD for common variants, but not for rare coding variants. These results were directionally consistent among COPD cases and controls.

IMPLICATIONS

We examined both common and rare coding variants associated with CPD in a large population of heavy smokers with and without COPD of NHW and AA descent. We replicated genome-wide significant associations on chromosome 15q25 with CPD for common variants among NHW subjects, but not for rare variants. We demonstrated for the first time that common variants on chromosome 15q25 associated with CPD are similar among COPD cases and controls. Previously reported associations on chromosome 19 showed suggestive and directionally consistent associations among common variants (RAB4, CYP2A7, and CYP2B6) and for rare variants (CYP2A7) among COPDGene NHW subjects. Although the genetic effect sizes for these single nucleotide polymorphisms on chromosome 15q25 are modest, we show that this creates a substantial smoking burden over the lifetime of a smoker.

C. elegans expressing D76N β2-microglobulin: a model for in vivo screening of drug candidates targeting amyloidosis

The availability of a genetic model organism with which to study key molecular events underlying amyloidogenesis is crucial for elucidating the mechanism of the disease and the exploration of new therapeutic avenues. The natural human variant of β2-microglobulin (D76N β2-m) is associated with a fatal familial form of systemic amyloidosis. Hitherto, no animal model has been available for studying in vivo the pathogenicity of this protein. We have established a transgenic C. elegans line, expressing the human D76N β2-m variant. Using the INVertebrate Automated Phenotyping Platform (INVAPP) and the algorithm Paragon, we were able to detect growth and motility impairment in D76N β2-m expressing worms. We also demonstrated the specificity of the β2-m variant in determining the pathological phenotype by rescuing the wild type phenotype when β2-m expression was inhibited by RNA interference (RNAi). Using this model, we have confirmed the efficacy of doxycycline, an inhibitor of the aggregation of amyloidogenic proteins, in rescuing the phenotype. In future, this C. elegans model, in conjunction with the INVAPP/Paragon system, offers the prospect of high-throughput chemical screening in the search for new drug candidates.

Cost-Effectiveness Of Once-Daily Single-Inhaler Triple Therapy In COPD: The IMPACT Trial

Background

We assessed the cost-effectiveness of single-inhaler fluticasone furoate (FF)/umeclidinium (UMEC)/vilanterol (VI) versus FF/VI or UMEC/VI from a Canadian public healthcare perspective, incorporating data from the IMPACT trial in chronic obstructive pulmonary disease (COPD) (NCT02164513).

Methods

Baseline inputs and treatment effects from IMPACT were populated into the validated GALAXY-COPD disease progression model. Canadian unit costs and drug costs (Canadian dollars [C$], 2017) were applied to healthcare resource utilization and treatments. Future costs and health outcomes were discounted at 1.5% annually. Analyses were probabilistic, and outputs included exacerbation rates, costs, and life years (LYs) and quality-adjusted life years (QALYs) gained.

Results

Compared with FF/VI and UMEC/VI over a lifetime horizon, the analyses predicted that treatment with FF/UMEC/VI resulted in fewer moderate and severe exacerbations, more LYs and more QALYs gained, with a small incremental cost. The base-case incremental cost-effectiveness ratio (ICER) per QALY gained was C$18,989 (95% confidence interval [CI]: C$14,665, C$25,753) versus FF/VI and C$13,776 (95% CI: C$9787, C$19,448) versus UMEC/VI. FF/UMEC/VI remained cost-effective versus both FF/VI and UMEC/VI in all sensitivity analyses, including in scenario analyses that considered different intervention and comparator discontinuation rates, and treatment effects for subsequent therapy.

Conclusion

Treatment with FF/UMEC/VI was predicted to improve outcomes and be a cost-effective treatment option for patients with symptomatic COPD and a history of exacerbations compared with FF/VI or UMEC/VI, in Canada.

Blood eosinophils and treatment response with triple and dual combination therapy in chronic obstructive pulmonary disease: analysis of the IMPACT trial

BACKGROUND

Previous studies have highlighted a relationship between reduction in rate of exacerbations with therapies containing inhaled corticosteroids (ICS) and baseline blood eosinophil count in patients with chronic obstructive pulmonary disease (COPD). The IMPACT trial showed that once-daily single-inhaler triple therapy significantly reduced exacerbations versus dual therapies. Blood eosinophil counts and smoking status could be important modifiers of treatment response to ICS. We aimed to model these relationships and their interactions, including outcomes other than exacerbations.

METHODS

IMPACT was a phase 3, randomised, double-blind, parallel-group, 52-week global study comparing once-daily single-inhaler triple therapy (fluticasone furoate-umeclidinium-vilanterol) with dual inhaled therapy (fluticasone furoate-vilanterol or umeclidinium-vilanterol). Eligible patients had moderate-to-very-severe COPD and at least one moderate or severe exacerbation in the previous year. We used fractional polynomials to model continuous blood eosinophil counts. We used negative binomial regression for numbers of moderate and severe exacerbations, severe exacerbations, and pneumonia. We modelled differences at week 52 in trough FEV₁, St George's Respiratory Questionnaire (SGRQ) total score, and Transition Dyspnoea Index using repeated measurements mixed effect models. IMPACT was registered with ClinicalTrials.gov, number NCT02164513.

FINDINGS

The magnitude of benefit of regimens containing ICS (fluticasone furoate-umeclidinium-vilanterol n=4151 and fluticasone furoate-vilanterol n=4134) in reducing rates of moderate and severe exacerbations increased in proportion with blood eosinophil count, compared with a non-ICS dual long-acting bronchodilator (umeclidinium-vilanterol n=2070). The moderate and severe exacerbation rate ratio for triple therapy versus umeclidinium-vilanterol was 0·88 (95% CI 0·74 to 1·04) at blood eosinophil count less than 90 cells per μL and 0·56 (0·47 to 0·66) at counts of 310 cells per μL or more; the corresponding rate ratio for fluticasone furoate-vilanterol versus umeclidinium-vilanterol was 1·09 (0·91 to 1·29) and 0·56 (0·47 to 0·66), respectively. Similar results were observed for FEV₁, Transition Dyspnoea Index, and SGRQ total score; however, the relationship with FEV₁ was less marked. At blood eosinophil counts less than 90 cells per μL and at counts of 310 cells per μL or more, the triple therapy versus umeclidinium-vilanterol treatment difference was 40 mL (95% CI 10 to 70) and 60 mL (20 to 100) for trough FEV₁, -0·01 (-0·68 to 0·66) and 0·30 (-0·37 to 0·97) for Transition Dyspnoea Index score, and -0·01 (-1·81 to 1·78) and -2·78 (-4·64 to -0·92) for SGRQ total score, respectively. Smoking status modified the relationship between observed efficacy and blood eosinophil count for moderate or severe exacerbations, Transition Dyspnoea Index, and FEV₁, with former smokers being more corticosteroid responsive at any eosinophil count than current smokers.

INTERPRETATION

This analysis of the IMPACT trial shows that assessment of blood eosinophil count and smoking status has the potential to optimise ICS use in clinical practice in patients with COPD and a history of exacerbations.

FUNDING

GlaxoSmithKline.

It's more than low BMI: prevalence of cachexia and associated mortality in COPD

BACKGROUND

Cachexia is associated with increased mortality risk among chronic obstructive pulmonary disease (COPD) patients. However, low body mass index (BMI) as opposed to cachexia is often used, particularly when calculating the BODE (BMI, Obstruction, Dyspnea and Exercise) index. For this reason, we examined mortality using a consensus definition and a weight-loss definition of cachexia among COPD cases and compared two new COPD severity indices with BODE.

METHODS

In the current report, the consensus definition for cachexia incorporated weight-loss > 5% in 12-months or low BMI in addition to 3/5 of decreased muscle strength, fatigue, anorexia, low FFMI and inflammation. The weight-loss definition incorporated weight-loss > 5% or weight-loss > 2% (if low BMI) in 12-months. The low BMI component in BODE was replaced with the consensus definition to create the CODE (Consensus cachexia, Obstruction, Dyspnea and Exercise) index and the weight-loss definition to create the WODE (Weight loss, Obstruction, Dyspnea and Exercise) index. Mortality was assessed using Kaplan-Meier survival and Cox Regression. Performance of models was compared using C-statistics.

RESULTS

Among 1483 COPD cases, the prevalences of cachexia by the consensus and weight-loss definitions were 4.7 and 10.4%, respectively. Cachectic patients had a greater than three-fold increased mortality by either the consensus or the weight-loss definition of cachexia independent of BMI and lung function. The CODE index predicted mortality slightly more accurately than the BODE and WODE indices.

CONCLUSIONS

Cachexia is associated with increased mortality among COPD patients. Monitoring cachexia using weight-loss criteria is relatively simple and predictive of mortality among COPD cases who may be missed if only low BMI is used.

Genetic landscape of chronic obstructive pulmonary disease identifies heterogeneous cell-type and phenotype associations

Chronic obstructive pulmonary disease (COPD) is the leading cause of respiratory mortality worldwide. Genetic risk loci provide new insights into disease pathogenesis. We performed a genome-wide association study in 35,735 cases and 222,076 controls from the UK Biobank and additional studies from the International COPD Genetics Consortium. We identified 82 loci associated with P < 5 × 10-8; 47 of these were previously described in association with either COPD or population-based measures of lung function. Of the remaining 35 new loci, 13 were associated with lung function in 79,055 individuals from the SpiroMeta consortium. Using gene expression and regulation data, we identified functional enrichment of COPD risk loci in lung tissue, smooth muscle, and several lung cell types. We found 14 COPD loci shared with either asthma or pulmonary fibrosis. COPD genetic risk loci clustered into groups based on associations with quantitative imaging features and comorbidities. Our analyses provide further support for the genetic susceptibility and heterogeneity of COPD.

Heteropolymerization of α-1-antitrypsin mutants in cell models mimicking heterozygosity

The most common genotype associated with severe α-1-antitrypsin deficiency (AATD) is the Z homozygote. The Z variant (Glu342Lys) of α-1-antitrypsin (AAT) undergoes a conformational change and is retained within the endoplasmic reticulum (ER) of hepatocytes leading to the formation of ordered polymeric chains and inclusion bodies. Accumulation of mutated protein predisposes to cirrhosis whilst plasma AAT deficiency leads to emphysema. Increased risk of liver and lung disease has also been reported in heterozygous subjects who carry Z in association with the milder S allele (Glu264Val) or even with wild-type M. However, it is unknown whether Z AAT can co-polymerize with other AAT variants in vivo. We co-expressed two AAT variants, each modified by a different tag, in cell models that replicate AAT deficiency. We used pull-down assays to investigate interactions between co-expressed variants and showed that Z AAT forms heteropolymers with S and with the rare Mmalton (Phe52del) and Mwurzburg (Pro369Ser) mutants, and to a lesser extent with the wild-type protein. Heteropolymers were recognized by the 2C1 mAb that binds to Z polymers in vivo. There was increased intracellular accumulation of AAT variants when co-expressed with Z AAT, suggesting a dominant negative effect of the Z allele. The molecular interactions between S and Z AAT were confirmed by confocal microscopy showing their colocalization within dilated ER cisternae and by positivity in Proximity Ligation Assays. These results provide the first evidence of intracellular co-polymerization of AAT mutants and contribute to understanding the risk of liver disease in SZ and MZ heterozygotes.

Characterisation of a type II functionally-deficient variant of alpha-1-antitrypsin discovered in the general population

Lung disease in alpha-1-antitrypsin deficiency (AATD) results from dysregulated proteolytic activity, mainly by neutrophil elastase (HNE), in the lung parenchyma. This is the result of a substantial reduction of circulating alpha-1-antitrypsin (AAT) and the presence in the plasma of inactive polymers of AAT. Moreover, some AAT mutants have reduced intrinsic activity toward HNE, as demonstrated for the common Z mutant, as well as for other rarer variants. Here we report the identification and characterisation of the novel AAT reactive centre loop variant Gly349Arg (p.G373R) present in the ExAC database. This AAT variant is secreted at normal levels in cellular models of AATD but shows a severe reduction in anti-HNE activity. Biochemical and molecular dynamics studies suggest it exhibits unfavourable RCL presentation to cognate proteases and compromised insertion of the RCL into β-sheet A. Identification of a fully dysfunctional AAT mutant that does not show a secretory defect underlines the importance of accurate genotyping of patients with pulmonary AATD manifestations regardless of the presence of normal levels of AAT in the circulation. This subtype of disease is reminiscent of dysfunctional phenotypes in anti-thrombin and C1-inibitor deficiencies so, accordingly, we classify this variant as the first pure functionally-deficient (type II) AATD mutant.

Whole exome sequencing analysis in severe chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), one of the leading causes of death worldwide, is substantially influenced by genetic factors. Alpha-1 antitrypsin deficiency demonstrates that rare coding variants of large effect can influence COPD susceptibility. To identify additional rare coding variants in patients with severe COPD, we conducted whole exome sequencing analysis in 2543 subjects from two family-based studies (Boston Early-Onset COPD Study and International COPD Genetics Network) and one case-control study (COPDGene). Applying a gene-based segregation test in the family-based data, we identified significant segregation of rare loss of function variants in TBC1D10A and RFPL1 (P-value < 2x10-6), but were unable to find similar variants in the case-control study. In single-variant, gene-based and pathway association analyses, we were unable to find significant findings that replicated or were significant in meta-analysis. However, we found that the top results in the two datasets were in proximity to each other in the protein-protein interaction network (P-value = 0.014), suggesting enrichment of these results for similar biological processes. A network of these association results and their neighbors was significantly enriched in the transforming growth factor beta-receptor binding and cilia-related pathways. Finally, in a more detailed examination of candidate genes, we identified individuals with putative high-risk variants, including patients harboring homozygous mutations in genes associated with cutis laxa and Niemann-Pick Disease Type C. Our results likely reflect heterogeneity of genetic risk for COPD along with limitations of statistical power and functional annotation, and highlight the potential of network analysis to gain insight into genetic association studies.

hiPSC hepatocyte model demonstrates the role of unfolded protein response and inflammatory networks in α1-antitrypsin deficiency

BACKGROUND & AIMS

α1-Antitrypsin deficiency (A1ATD) is an autosomal recessive disorder caused by mutations in the SERPINA1 gene. Individuals with the Z variant (Gly342Lys) retain polymerised protein in the endoplasmic reticulum (ER) of their hepatocytes, predisposing them to liver disease. The concomitant lack of circulating A1AT also causes lung emphysema. Greater insight into the mechanisms that link protein misfolding to liver injury will facilitate the design of novel therapies.

METHODS

Human-induced pluripotent stem cell (hiPSC)-derived hepatocytes provide a novel approach to interrogate the molecular mechanisms of A1ATD because of their patient-specific genetic architecture and reflection of human physiology. To that end, we utilised patient-specific hiPSC hepatocyte-like cells (ZZ-HLCs) derived from an A1ATD (ZZ) patient, which faithfully recapitulated key aspects of the disease at the molecular and cellular level. Subsequent functional and "omics" comparisons of these cells with their genetically corrected isogenic-line (RR-HLCs) and primary hepatocytes/human tissue enabled identification of new molecular markers and disease signatures.

RESULTS

Our studies showed that abnormal A1AT polymer processing (immobilised ER components, reduced luminal protein mobility and disrupted ER cisternae) occurred heterogeneously within hepatocyte populations and was associated with disrupted mitochondrial structure, presence of the oncogenic protein AKR1B10 and two upregulated molecular clusters centred on members of inflammatory (IL-18 and Caspase-4) and unfolded protein response (Calnexin and Calreticulin) pathways. These results were validated in a second patient-specific hiPSC line.

CONCLUSIONS

Our data identified novel pathways that potentially link the expression of Z A1AT polymers to liver disease. These findings could help pave the way towards identification of new therapeutic targets for the treatment of A1ATD.

LAY SUMMARY

This study compared the gene expression and protein profiles of healthy liver cells and those affected by the inherited disease α1-antitrypsin deficiency. This approach identified specific factors primarily present in diseased samples which could provide new targets for drug development. This study also demonstrates the interest of using hepatic cells generated from human-induced pluripotent stem cells to model liver disease in vitro for uncovering new mechanisms with clinical relevance.

New Therapeutic Targets for Alpha-1 Antitrypsin Deficiency

Alpha-1antitrypsin deficiency (AATD) results from the intracellular polymerization and retention of mutant alpha-1antitrypsin (AAT) within the endoplasmic reticulum of hepatocytes. This causes cirrhosis whilst the deficiency of circulating AAT predisposes to early onset emphysema. This is an exciting time for researchers in the field with the development of novel therapies based on understanding the pathobiology of disease. I review here augmentation therapy to prevent the progression of lung disease and a range of approaches to treat the liver disease associated with the accumulation of mutant AAT: modifying proteostasis networks that are activated by Z AAT polymers, stimulating autophagy, small interfering RNA and small molecules to block intracellular polymerization, and stem cell technology to correct the genetic defect that underlies AATD.

Single-inhaler triple therapy in symptomatic COPD patients: FULFIL subgroup analyses

Triple inhaled corticosteroid (ICS)/long-acting muscarinic antagonist (LAMA)/long-acting β₂-agonist (LABA) therapy is recommended for symptomatic patients with chronic obstructive pulmonary disease (COPD) and at risk of exacerbations. However, the benefits versus side-effects of triple inhaled therapy for COPD, based on distinct patient clinical profiles, are unclear.

FULFIL, a phase III, randomised, double-blind study, compared 24 weeks of once-daily fluticasone furoate/umeclidinium/vilanterol (FF/UMEC/VI) 100/62.5/25 µg using the Ellipta inhaler with twice-daily budesonide/formoterol (BUD/FOR) 400/12 µg using the Turbuhaler. Subgroup analyses of forced expiratory volume in 1 s (FEV₁), St George's Respiratory Questionnaire (SGRQ) Total score and exacerbation rates were carried out. Subgroups were defined by COPD medication at screening (ICS+LABA, BUD+FOR, ICS+LABA+LAMA, LAMA alone, tiotropium alone and LAMA+LABA), by disease severity (lung function and exacerbations) and by exacerbation history (exacerbation severity and frequency).

In the intent-to-treat population (n=1810) at week 24, FF/UMEC/VI (n=911) versus BUD/FOR (n=899) improved FEV₁ and SGRQ Total score and reduced mean annual exacerbation rates in all disease severity and exacerbation history subgroups. FF/UMEC/VI versus BUD/FOR improved FEV₁ and SGRQ Total score in all medication subgroups and reduced mean annual exacerbation rates in all medication subgroups, except LAMA+LABA. Adverse events were similar across subgroups.

These findings support the benefit of FF/UMEC/VI compared with dual ICS/LABA therapy in patients with symptomatic COPD regardless of disease severity or prior treatment and may help to inform clinical decision making.

Single-inhaler triple therapy for COPD provides clinical benefit across a wide spectrum of disease characteristicshttp://ow.ly/ETBv30iXQ97

Once-Daily Single-Inhaler Triple versus Dual Therapy in Patients with COPD

BACKGROUND

The benefits of triple therapy for chronic obstructive pulmonary disease (COPD) with an inhaled glucocorticoid, a long-acting muscarinic antagonist (LAMA), and a long-acting β₂-agonist (LABA), as compared with dual therapy (either inhaled glucocorticoid-LABA or LAMA-LABA), are uncertain.

METHODS

In this randomized trial involving 10,355 patients with COPD, we compared 52 weeks of a once-daily combination of fluticasone furoate (an inhaled glucocorticoid) at a dose of 100 μg, umeclidinium (a LAMA) at a dose of 62.5 μg, and vilanterol (a LABA) at a dose of 25 μg (triple therapy) with fluticasone furoate-vilanterol (at doses of 100 μg and 25 μg, respectively) and umeclidinium-vilanterol (at doses of 62.5 μg and 25 μg, respectively). Each regimen was administered in a single Ellipta inhaler. The primary outcome was the annual rate of moderate or severe COPD exacerbations during treatment.

RESULTS

The rate of moderate or severe exacerbations in the triple-therapy group was 0.91 per year, as compared with 1.07 per year in the fluticasone furoate-vilanterol group (rate ratio with triple therapy, 0.85; 95% confidence interval [CI], 0.80 to 0.90; 15% difference; P<0.001) and 1.21 per year in the umeclidinium-vilanterol group (rate ratio with triple therapy, 0.75; 95% CI, 0.70 to 0.81; 25% difference; P<0.001). The annual rate of severe exacerbations resulting in hospitalization in the triple-therapy group was 0.13, as compared with 0.19 in the umeclidinium-vilanterol group (rate ratio, 0.66; 95% CI, 0.56 to 0.78; 34% difference; P<0.001). There was a higher incidence of pneumonia in the inhaled-glucocorticoid groups than in the umeclidinium-vilanterol group, and the risk of clinician-diagnosed pneumonia was significantly higher with triple therapy than with umeclidinium-vilanterol, as assessed in a time-to-first-event analysis (hazard ratio, 1.53; 95% CI, 1.22 to 1.92; P<0.001).

CONCLUSIONS

Triple therapy with fluticasone furoate, umeclidinium, and vilanterol resulted in a lower rate of moderate or severe COPD exacerbations than fluticasone furoate-vilanterol or umeclidinium-vilanterol in this population. Triple therapy also resulted in a lower rate of hospitalization due to COPD than umeclidinium-vilanterol. (Funded by GlaxoSmithKline; IMPACT ClinicalTrials.gov number, NCT02164513 .).