Loss of ADAM15 in female mice does not worsen pressure overload cardiomyopathy, independent of ovarian hormones

Cardiac hypertrophy is a common feature in several cardiomyopathies. We previously reported that loss of ADAM15 (disintegrin and metalloproteinase 15) worsened cardiac hypertrophy and dilated cardiomyopathy following cardiac pressure overload. Here, we investigated the impact of ADAM15 loss in female mice following cardiac pressure overload induced by transverse aortic constriction (TAC). Female Adam15-/-mice developed the same degree of cardiac hypertrophy, dilation and dysfunction as the parallel female wildtype (WT) mice at 6 weeks post-TAC. To determine if this is due to the protective effects of estrogen which could mask the negative impact of Adam15 loss, WT and Adam15-/- mice underwent ovariectomy (OVx) 2 weeks prior to TAC. Cardiac structure and function analyses were performed at 6 weeks post-TAC. OVx similarly impacted females of both genotypes post-TAC. Calcineurin (Cn) activity was increased post-OVx-TAC, and more in Adam15-/- mice, however this increase was not reflected in the total-to-phospho NFAT levels. Integrin α7 expression, which was upstream of Cn activation in male Adam15-/--TAC mice, remained unchanged in female mice. However, activation of the Mitogen Activated Protein Kinases (ERK, JNK, P38) were greater in Adam15-/--OVx-TAC compared to WT-OVx-TAC mice. In addition, ADAM15 protein levels were significantly increased post-TAC in male but not in female WT mice. Myocardial fibrosis was comparable in non-OVx WT-TAC and Adam15-/--TAC mice. OVx increased the perivascular fibrosis more in Adam15-/- compared to WT mice post-TAC. Our data demonstrate that loss of ovarian hormones did not fully replicate the male phenotype in the female Adam15-/- mice post-TAC. Since ADAM15 levels were increased in males but not in females post-TAC, it is plausible that ADAM15 does not play a prominent role in post-TAC events in female mice. Our findings highlight the significance of factors other than sex hormones in mediating cardiomyopathies in females, which require a more thorough understanding.

CC16 augmentation reduces exaggerated COPD-like disease in Cc16-deficient mice

Low Club Cell 16 kDa protein (CC16) plasma levels are linked to accelerated lung function decline in patients with chronic obstructive pulmonary disease (COPD). Cigarette smoke-exposed (CS-exposed) Cc16-/- mice have exaggerated COPD-like disease associated with increased NF-κB activation in their lungs. It is unclear whether CC16 augmentation can reverse exaggerated COPD in CS-exposed Cc16-/- mice and whether increased NF-κB activation contributes to the exaggerated COPD in CS-exposed Cc16-/- lungs. CS-exposed WT and Cc16-/- mice were treated with recombinant human CC16 (rhCC16) or an NF-κB inhibitor versus vehicle beginning at the midpoint of the exposures. COPD-like disease and NF-κB activation were measured in the lungs. RhCC16 limited the progression of emphysema, small airway fibrosis, and chronic bronchitis-like disease in WT and Cc16-/- mice partly by reducing pulmonary inflammation (reducing myeloid leukocytes and/or increasing regulatory T and/or B cells) and alveolar septal cell apoptosis, reducing NF-κB activation in CS-exposed Cc16-/- lungs, and rescuing the reduced Foxj1 expression in CS-exposed Cc16-/- lungs. IMD0354 treatment reduced exaggerated lung inflammation and rescued the reduced Foxj1 expression in CS-exposed Cc16-/- mice. RhCC16 treatment reduced NF-κB activation in luciferase reporter A549 cells. Thus, rhCC16 treatment limits COPD progression in CS-exposed Cc16-/- mice partly by inhibiting NF-κB activation and represents a potentially novel therapeutic approach for COPD.

Extracellular vesicle-encapsulated CC16 as novel nanotherapeutics for treatment of acute lung injury

Acute lung injury (ALI) is still associated with high mortality. Growing evidence suggests that Club Cell Protein 16 (CC16) plays a protective role against ALI. However, the doses of recombinant CC16 (rCC16) used in preclinical studies are supraphysiological for clinical applications. Extracellular vesicles (EVs) are nanovesicles endogenously generated by mammalian cells. Our study demonstrated that CC16 is released via small EVs and EV-encapsulated CC16 (sEV-CC16) and has anti-inflammatory activities, which protect mice from lipopolysaccharide (LPS) or bacteria-induced ALI. Additionally, sEV-CC16 can activate the DNA damage repair signaling pathways. Consistent with this activity, we observed more severe DNA damage in lungs from Cc16 knockout (KO) than wild-type (WT) mice. Mechanistically, we elucidated that CC16 suppresses nuclear factor κB (NF-κB) signaling activation by binding to heat shock protein 60 (HSP60). We concluded that sEV-CC16 could be a potential therapeutic agent for ALI by inhibiting the inflammatory and DNA damage responses by reducing NF-κB signaling.

Loss of ADAM15 Exacerbates Transition to Decompensated Myocardial Hypertrophy and Dilation Through Activation of the Calcineurin Pathway

BACKGROUND

Myocardial hypertrophy and dilation are key features of cardiomyopathies and involve several cellular and molecular events. ADAMs (a disintegrin and metalloproteinases) are membrane-bound proteinases with diverse functions whose role in heart disease remains underexplored. ADAM15 is expressed in the heart and is downregulated in the failing human heart. We investigated the role ADAM15 in pressure overload cardiomyopathy.

METHODS

We assessed ADAM15 levels in myocardial specimens from patients. Its direct role in pressure overload was investigated by subjecting wildtype and Adam15-deficient mice to transverse aortic constriction (TAC).

RESULTS

ADAM15 levels did not change in patients with concentric hypertrophy, but markedly decreased in eccentric hypertrophy and heart failure. Loss of ADAM15 alone did not cause cardiomyopathy in mice (1 year old). After TAC, Adam15^-/- mice exhibited worsened eccentric hypertrophy and dilation with greater increase in hypertrophy markers (pJNK, pERK1/2; Nppb, Nppa, Myh7, Acta1) compared with wildtype-TAC. Expression of integrin-α7 (but not integrin β1) increased significantly more in Adam15^-/--TAC hearts, while the interaction of these integrins with basement membrane (laminin), decreased consistent with worsened left ventricle dilation. In vitro, ADAM15 knockdown increased cardiomyocyte hypertrophy in response to mechanical stretch. Adam15^-/--TAC hearts exhibited increased calcineurin activity and de-phosphorylation of nuclear factor of activated T cells. Calcineurin inhibition (cyclosporin-A) blocked the excess hypertrophy and dilation in Adam15^-/--TAC mice. Proteome profiling demonstrated the increased abundance of the key proteins linked to worsened DCM in Adam15^-/--TAC.

CONCLUSION

This is the first report demonstrating that ADAM15 can suppress hypertrophy through regulating the integrin-laminin interaction and the calcineurin pathway.

Dysregulation of miR-103a Mediates Cigarette Smoking-induced Lipid-laden Macrophage Formation

Cigarette smoke (CS) is considered a major risk factor for chronic obstructive pulmonary disease (COPD) that is currently the third leading cause of death in the United States. Studies have indicated that patients with COPD have elevated blood low-density lipoprotein levels, which may contribute to the dysregulation of lipid metabolism. Accumulating data show that microRNAs (miRNAs) are involved in various human diseases. However, the role of microRNAs in the pathogenesis of COPD remains poorly defined. In this study, we found that miR-103a expression was significantly reduced in alveolar macrophages from smokers and patients with COPD versus that in alveolar macrophages from nonsmokers. Our data indicated that reactive oxygen species negatively regulate miR-103a in macrophages. Functionally, miR-103a modulates the expressions of genes involved in lipid metabolism and directly targets low-density lipoprotein receptors in macrophages. Furthermore, overexpression of miR-103a suppressed the accumulation of lipid droplets and reduced the reactive oxygen species, both in vitro and in vivo. Taken together, our findings indicate that downregulation of miR-103a contributes to cigarette smoke-induced lipid-laden macrophage formation and plays a critical role in lipid homeostasis in lung macrophages in the pathogenesis of COPD.

Association of clonal hematopoiesis with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is associated with age and smoking, but other determinants of the disease are incompletely understood. Clonal hematopoiesis of indeterminate potential (CHIP) is a common, age-related state in which somatic mutations in clonal blood populations induce aberrant inflammatory responses. Patients with CHIP have an elevated risk for cardiovascular disease, but the association of CHIP with COPD remains unclear. We analyzed whole-genome sequencing and whole-exome sequencing data to detect CHIP in 48 835 patients, of whom 8444 had moderate to very severe COPD, from four separate cohorts with COPD phenotyping and smoking history. We measured emphysema in murine models in which Tet2 was deleted in hematopoietic cells. In the COPDGene cohort, individuals with CHIP had risks of moderate-to-severe, severe, or very severe COPD that were 1.6 (adjusted 95% confidence interval [CI], 1.1-2.2) and 2.2 (adjusted 95% CI, 1.5-3.2) times greater than those for noncarriers. These findings were consistently observed in three additional cohorts and meta-analyses of all patients. CHIP was also associated with decreased FEV1% predicted in the COPDGene cohort (mean between-group differences, -5.7%; adjusted 95% CI, -8.8% to -2.6%), a finding replicated in additional cohorts. Smoke exposure was associated with a small but significant increased risk of having CHIP (odds ratio, 1.03 per 10 pack-years; 95% CI, 1.01-1.05 per 10 pack-years) in the meta-analysis of all patients. Inactivation of Tet2 in mouse hematopoietic cells exacerbated the development of emphysema and inflammation in models of cigarette smoke exposure. Somatic mutations in blood cells are associated with the development and severity of COPD, independent of age and cumulative smoke exposure.

ADAM15 is required for optimal collagen cross-linking and scar formation following myocardial infarction

Collagen cross-linking is an important step in optimal scar formation. Myocardial infarction (MI) results in loss of cardiomyocytes that are replaced with a scar (infarct) tissue. Disintegrin and metalloproteinases (ADAMs) are membrane-bound proteases that can interact with molecules intra- and extra-cellularly to mediate various cellular functions. ADAM15 is expressed in the myocardium, however its function in heart disease has been poorly explored. We utilized mice lacking ADAM15 (Adam15^-/-) and wildtype (WT) mice. MI, induced by ligation of the left anterior descending artery, resulted in a transient but significant rise in ADAM15 protein in the WT myocardium at 3-days. Following MI, Adam15^-/- mice exhibited markedly higher rate of left ventricular (LV) rupture compared to WT mice (66% vs. 15%, p<0.05). Echocardiography and strain analyses showed worsened LV dysfunction in Adam15^-/- mice at 3days, prior to the onset of LV rupture. Second harmonic generation imaging revealed significant disarray and reduction in fibrillar collagen density in Adam15^-/- compared to WT hearts. This was associated with lower insoluble and higher soluble collagen fractions, reduced cross-linking enzyme, lysyl oxidase-1 (LOX-1), and fibronectin which is required for LOX-1 function, in Adam15^-/--MI hearts. Post-MI myocardial inflammation was comparable between the genotypes. In vitro, primary adult cardiac fibroblasts from Adam15^-/- mice showed suppressed activation in response to ischemia (hypoxia+nutrient depletion) compared to WT fibroblasts. Adam15-deficiency was associated with reduced PAK1(p21-activated kinase-1) levels, a regulator of fibronectin and LOX-1 expression. In female mice, the rate of post-MI LV rupture, PAK1 signaling, LOX-1 and fibronectin protein levels were comparable between Adam15^-/- and WT, indicating lack of sex-dependent effects of ADAM15 post- MI. This study reports a novel function for ADAM15 in collagen cross-linking and optimal scar formation post-MI which may also apply to scar formation in other tissues.

A Novel Protective Role for Matrix Metalloproteinase-8 in the Pulmonary Vasculature

Rationale: Mechanical signaling through cell-matrix interactions plays a major role in progressive vascular remodeling in pulmonary arterial hypertension (PAH). MMP-8 (matrix metalloproteinase-8) is an interstitial collagenase involved in regulating inflammation and fibrosis of the lung and systemic vasculature, but its role in PAH pathogenesis remains unexplored. Objectives: To evaluate MMP-8 as a modulator of pathogenic mechanical signaling in PAH. Methods: MMP-8 levels were measured in plasma from patients with pulmonary hypertension (PH) and controls by ELISA. MMP-8 vascular expression was examined in lung tissue from patients with PAH and rodent models of PH. MMP-8-/- and MMP-8+/+ mice were exposed to normobaric hypoxia or normoxia for 4-8 weeks. PH severity was evaluated by right ventricular systolic pressure, echocardiography, pulmonary artery morphometry, and immunostaining. Proliferation, migration, matrix component expression, and mechanical signaling were assessed in MMP-8-/- and MMP-8+/+ pulmonary artery smooth muscle cells (PASMCs). Measurements and Main Results: MMP-8 expression was significantly increased in plasma and pulmonary arteries of patients with PH compared with controls and induced in the pulmonary vasculature in rodent PH models. Hypoxia-exposed MMP-8-/- mice had significant mortality, increased right ventricular systolic pressure, severe right ventricular dysfunction, and exaggerated vascular remodeling compared with MMP-8+/+ mice. MMP-8-/- PASMCs demonstrated exaggerated proliferation and migration mediated by altered matrix protein expression, elevated integrin-β3 levels, and induction of FAK (focal adhesion kinase) and downstream YAP (Yes-associated protein)/TAZ (transcriptional coactivator with PDZ-binding motif) activity. Conclusions: MMP-8 is a novel protective factor upregulated in the pulmonary vasculature during PAH pathogenesis. MMP-8 opposes pathologic mechanobiological feedback by altering matrix composition and disrupting integrin-β3/FAK and YAP/TAZ-dependent mechanical signaling in PASMCs.

Metformin: Experimental and Clinical Evidence for a Potential Role in Emphysema Treatment

Rationale: Cigarette smoke (CS) inhalation triggers oxidative stress and inflammation, leading to accelerated lung aging, apoptosis, and emphysema, as well as systemic pathologies. Metformin is beneficial for protecting against aging-related diseases. Objectives: We sought to investigate whether metformin may ameliorate CS-induced pathologies of emphysematous chronic obstructive pulmonary disease (COPD). Methods: Mice were exposed chronically to CS and fed metformin-enriched chow for the second half of exposure. Lung, kidney, and muscle pathologies, lung proteostasis, endoplasmic reticulum (ER) stress, mitochondrial function, and mediators of metformin effects in vivo and/or in vitro were studied. We evaluated the association of metformin use with indices of emphysema progression over 5 years of follow-up among the COPDGene (Genetic Epidemiology of COPD) study participants. The association of metformin use with the percentage of emphysema and adjusted lung density was estimated by using a linear mixed model. Measurements and Main Results: Metformin protected against CS-induced pulmonary inflammation and airspace enlargement; small airway remodeling, glomerular shrinkage, oxidative stress, apoptosis, telomere damage, aging, dysmetabolism in vivo and in vitro; and ER stress. The AMPK (AMP-activated protein kinase) pathway was central to metformin's protective action. Within COPDGene, participants receiving metformin compared with those not receiving it had a slower progression of emphysema (-0.92%; 95% confidence interval [CI], -1.7% to -0.14%; P = 0.02) and a slower adjusted lung density decrease (2.2 g/L; 95% CI, 0.43 to 4.0 g/L; P = 0.01). Conclusions: Metformin protected against CS-induced lung, renal, and muscle injury; mitochondrial dysfunction; and unfolded protein responses and ER stress in mice. In humans, metformin use was associated with lesser emphysema progression over time. Our results provide a rationale for clinical trials testing the efficacy of metformin in limiting emphysema progression and its systemic consequences.

Long-term safety of lumacaftor-ivacaftor in children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation: a multicentre, phase 3, open-label, extension study

BACKGROUND

A previous phase 3 study showed that lumacaftor-ivacaftor was generally safe and well tolerated over 24 weeks of treatment in children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation. In this study, we aimed to assess the long-term safety of lumacaftor-ivacaftor in a rollover study of children who participated in this previous phase 3 study.

METHODS

In this multicentre, phase 3, open-label, extension study (study 116; VX16-809-116), we assessed safety of lumacaftor-ivacaftor in children included in a previous multicentre, phase 3, open-label study (study 115; VX15-809-115). The study was done at 20 cystic fibrosis care centres in the USA and Canada. Children aged 2-5 years with cystic fibrosis homozygous for the F508del-CFTR mutation who completed 24 weeks of lumacaftor-ivacaftor treatment in study 115 received weight-based and age-based doses of oral lumacaftor-ivacaftor: children weighing less than 14 kg and aged younger than 6 years at study 116 screening received lumacaftor 100 mg-ivacaftor 125 mg every 12 h; children weighing 14 kg or more and aged younger than 6 years at screening received lumacaftor 150 mg-ivacaftor 188 mg every 12 h; and children aged 6 years or older received lumacaftor 200 mg-ivacaftor 250 mg every 12 h. Children received treatment for up to 96 weeks, equivalent to up to 120 weeks of treatment in total from the start of study 115 to completion of study 116. The primary endpoint was the safety and tolerability of the study drug in all participants who had received lumacaftor-ivacaftor for 24 weeks in study 115 and had received at least one dose in study 116. Secondary endpoints included change from baseline in study 115 at week 96 of study 116 in sweat chloride concentration, growth parameters, markers of pancreatic function, and lung clearance index (LCI) parameters in all children who received at least one dose of lumacaftor-ivacaftor in study 116. This study is registered with ClinicalTrials.gov, NCT03125395.

FINDINGS

This extension study ran from May 12, 2017, to July 17, 2019. Of 60 participants enrolled and who received lumacaftor-ivacaftor in study 115, 57 (95%) were included in study 116 and continued to receive the study drug. A total of 47 (82%) of 57 participants completed 96 weeks of treatment. Most participants (56 [98%] of 57) had at least one adverse event during study 116, most of which were mild (19 [33%] participants) or moderate (29 [51%] participants) in severity. The most common adverse events were cough (47 [82%] participants), nasal congestion (25 [44%] participants), pyrexia (23 [40%] participants), rhinorrhoea (18 [32%] participants), and vomiting (17 [30%] participants). A total of 15 (26%) participants had at least one serious adverse event; most were consistent with underlying cystic fibrosis or common childhood illnesses. Respiratory adverse events occurred in five (9%) participants, none of which were serious or led to treatment discontinuation. Elevated aminotransferase concentrations, most of which were mild or moderate in severity, occurred in ten (18%) participants. Three (5%) participants discontinued treatment due to adverse events (two due to increased aminotransferase concentrations [one of whom had concurrent pancreatitis], considered as possibly related to study drug; and one due to gastritis and metabolic acidosis, considered unlikely to be related to study drug). No clinically significant abnormalities or changes were seen in electrocardiograms, vital signs, pulse oximetry, ophthalmological examinations, or spirometry assessments. Improvements in secondary endpoints observed in study 115 were generally maintained up to week 96 of study 116, including improvements in sweat chloride concentration (mean absolute change from study 115 baseline at week 96 of study 116 -29·6 mmol/L [95% CI -33·7 to -25·5]), an increase in growth parameters and pancreatic function, and stable lung function relative to baseline, as measured by the LCI.

INTERPRETATION

Lumacaftor-ivacaftor was generally safe and well tolerated, and treatment effects were generally maintained for the duration of the extension study. These findings support the use of lumacaftor-ivacaftor for up to 120 weeks in young children with cystic fibrosis aged 2 years and older homozygous for the F508del-CFTR mutation.

FUNDING

Vertex Pharmaceuticals Incorporated.

Hedgehog interacting protein (HHIP) represses airway remodeling and metabolic reprogramming in COPD-derived airway smooth muscle cells

Although HHIP locus has been consistently associated with the susceptibility to COPD including airway remodeling and emphysema in genome-wide association studies, the molecular mechanism underlying this genetic association remains incompletely understood. By utilizing Hhip+/- mice and primary human airway smooth muscle cells (ASMCs), here we aim to determine whether HHIP haploinsufficiency increases airway smooth muscle mass by reprogramming glucose metabolism, thus contributing to airway remodeling in COPD pathogenesis. The mRNA levels of HHIP were compared in normal and COPD-derived ASMCs. Mitochondrial oxygen consumption rate and lactate levels in the medium were measured in COPD-derived ASMCs with or without HHIP overexpression as readouts of glucose oxidative phosphorylation and aerobic glycolysis rates. The proliferation rate was measured in healthy and COPD-derived ASMCs treated with or without 2-DG. Smooth muscle mass around airways was measured by immunofluorescence staining for α-smooth muscle actin (α-SMA) in lung sections from Hhip+/- mice and their wild type littermates, Hhip+/+ mice. Airway remodeling was assessed in Hhip+/- and Hhip+/- mice exposed to 6 months of cigarette smoke. Our results show HHIP inhibited aerobic glycolysis and represses cell proliferation in COPD-derived ASMCs. Notably, knockdown of HHIP in normal ASMCs increased PKM2 activity. Importantly, Hhip+/- mice demonstrated increased airway remodeling and increased intensity of α-SMA staining around airways compared to Hhip+/+ mice. In conclusion, our findings suggest that HHIP represses aerobic glycolysis and ASMCs hyperplasia, which may contribute to the increased airway remodeling in Hhip+/- mice.

Surface-bound matrix metalloproteinase-8 on macrophages: Contributions to macrophage pericellular proteolysis and migration through tissue barriers

Objective

MMP‐8 binds to surface‐bound tissue inhibitor of metalloproteinase‐1 (TIMP‐1) on PMNs to promote pericellular proteolysis during the development of inflammatory diseases associated with tissue destruction. Little is known about the biology of MMP‐8 in macrophages. We tested the hypotheses that: (1) MMP‐8 and TIMP‐1 are also expressed on the surface of activated macrophages, (2) surface‐bound MMP‐8 on macrophages promotes TIMP‐resistant pericellular proteolysis and macrophage migration through tissue barriers, and (3) MMP‐8 binds to surface‐bound TIMP‐1 on macrophages.

Methods

Surface MMP‐8 and TIMP‐1 levels were measured on human monocyte‐derived macrophages (MDM) and/or murine macrophages using immunostaining, biotin‐labeling, and substrate cleavage methods. The susceptibility of membrane‐bound Mmp‐8 on activated macrophages from wild‐type (WT) mice to TIMPs was measured. Migration of WT and Mmp‐8^−/− macrophages through models of tissue barriers in vitro and the accumulation of peritoneal macrophages in WT versus Mmp‐8^−/− mice with sterile peritonitis was compared. Surface levels of Mmp‐8 were compared on activated macrophages from WT and Timp‐1^−/− mice.

Results

Lipopolysaccharides and a cluster of differentiation 40 ligand increased surface MMP‐8 and/or TIMP‐1 staining and surface type I collagenase activity on MDM and/or murine macrophages. Activated Mmp‐8^−/− macrophages degraded less type I collagen than activated WT macrophages. The surface type‐I collagenase activity on WT macrophages was resistant to inhibition by Timp‐1. Peritoneal macrophage accumulation was similar in WT and Mmp‐8^−/− mice with sterile acute peritonitis. However, Mmp‐8^−/− macrophages migrated less efficiently through models of tissue barriers (especially those containing type I collagen) than WT cells. Activated WT and Timp‐1^−/− macrophages had similar surface‐bound Mmp‐8 levels.

Conclusions

MMP‐8 and TIMP‐1 are expressed on the surface of activated human MDM and murine macrophages, but Mmp‐8 is unlikely to bind to surface‐bound Timp‐1 on these cells. Surface‐bound MMP‐8 contributes to TIMP‐resistant monocyte/macrophage pericellular proteolysis and macrophage migration through collagen‐containing tissue barriers.

A disintegrin and metalloproteinase domain-15 deficiency leads to exaggerated cigarette smoke-induced chronic obstructive pulmonary disease (COPD)-like disease in mice

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by cells implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD), but its contributions to COPD are unknown. To address this gap, ADAM15 levels were measured in samples from cigarette smoke (CS)-versus air-exposed wild-type (WT) mice. CS-induced COPD-like disease was compared in CS-exposed WT, Adam15^-/-, and Adam15 bone marrow chimeric mice. CS exposure increased Adam15 expression in lung macrophages and CD8⁺ T cells and to a lesser extent in airway epithelial cells in WT mice. CS-exposed Adam15^-/- mice had greater emphysema, small airway fibrosis, and lung inflammation (macrophages and CD8⁺ T cells) than WT mice. Adam15 bone marrow chimera studies revealed that Adam15 deficiency in leukocytes led to exaggerated pulmonary inflammation and COPD-like disease in mice. Adam15 deficiency in CD8⁺ T cells was required for the exaggerated pulmonary inflammation and COPD-like disease in CS-exposed Adam15^-/- mice (as assessed by genetically deleting CD8⁺ T cells in Adam15^-/- mice). Adam15 deficiency increased pulmonary inflammation by rendering CD8⁺ T cells and macrophages resistant to CS-induced activation of the mitochondrial apoptosis pathway by preserving mTOR signaling and intracellular Mcl-1 levels in these cells. These results strongly link ADAM15 deficiency to the pathogenesis of COPD.

Long-term safety and efficacy of tezacaftor-ivacaftor in individuals with cystic fibrosis aged 12 years or older who are homozygous or heterozygous for Phe508del CFTR (EXTEND): an open-label extension study

BACKGROUND

Tezacaftor-ivacaftor is an approved cystic fibrosis transmembrane conductance regulator (CFTR) modulator shown to be efficacious and generally safe and well tolerated over 8-24 weeks in phase 3 clinical studies in participants aged 12 years or older with cystic fibrosis homozygous for the Phe508del CFTR mutation (F/F; study 661-106 [EVOLVE]) or heterozygous for the Phe508del CFTR mutation and a residual function mutation (F/RF; study 661-108 [EXPAND]). Longer-term (>24 weeks) safety and efficacy of tezacaftor-ivacaftor has not been assessed in clinical studies. Here, we present results of study 661-110 (EXTEND), a 96-week open-label extension study that assessed long-term safety, tolerability, and efficacy of tezacaftor-ivacaftor in participants aged 12 years or older with cystic fibrosis who were homozygous or heterozygous for the Phe508del CFTR mutation.

METHODS

Study 661-110 was a 96-week, phase 3, multicentre, open-label study at 170 clinical research sites in Australia, Europe, Israel, and North America. Participants were aged 12 years or older, had cystic fibrosis, were homozygous or heterozygous for Phe508del CFTR, and completed one of six parent studies of tezacaftor-ivacaftor: studies 661-103, 661-106, 661-107, 661-108, 661-109, and 661-111. Participants received oral tezacaftor 100 mg once daily and oral ivacaftor 150 mg once every 12 h for up to 96 weeks. The primary endpoint was safety and tolerability. Secondary endpoints were changes in lung function, nutritional parameters, and respiratory symptom scores; pulmonary exacerbations; and pharmacokinetic parameters. A post-hoc analysis assessed the rate of lung function decline in F/F participants who received up to 120 weeks of tezacaftor-ivacaftor in studies 661-106 (F/F) and/or 661-110 compared with a matched cohort of CFTR modulator-untreated historical F/F controls from the Cystic Fibrosis Foundation Patient Registry. Primary safety analyses were done in all participants from all six parent studies who received at least one dose of study drug during this study. This study was registered at ClinicalTrials.gov (NCT02565914).

FINDINGS

Between Aug 31, 2015, to May 31, 2019, 1044 participants were enrolled in study 661-110 from the six parent studies of whom 1042 participants received at least one dose of study drug and were included in the safety set. 995 (95%) participants had at least one TEAE; 22 (2%) had TEAEs leading to discontinuation; and 351 (34%) had serious TEAEs. No deaths occurred during the treatment-emergent period; after the treatment-emergent period, two deaths occurred, which were both deemed unrelated to study drug. F/F (106/110; n=459) and F/RF (108/110; n=226) participants beginning tezacaftor-ivacaftor in study 661-110 had improvements in efficacy endpoints consistent with parent studies; improvements in lung function and nutritional parameters and reductions in pulmonary exacerbations observed in the tezacaftor-ivacaftor groups in the parent studies were generally maintained in study 661-110 for an additional 96 weeks. Pharmacokinetic parameters were also similar to those in the parent studies. The annualised rate of lung function decline was 61·5% (95% CI 35·8 to 86·1) lower in tezacaftor-ivacaftor-treated F/F participants versus untreated matched historical controls.

INTERPRETATION

Tezacaftor-ivacaftor was generally safe, well tolerated, and efficacious for up to 120 weeks, and the safety profile of tezacaftor-ivacaftor in study 661-110 was consistent with cystic fibrosis manifestations and with the safety profiles of the parent studies. The rate of lung function decline was significantly reduced in F/F participants, consistent with cystic fibrosis disease modification. Our results support the clinical benefit of long-term tezacaftor-ivacaftor treatment for people aged 12 years or older with cystic fibrosis with F/F or F/RF genotypes.

FUNDING

Vertex Pharmaceuticals Incorporated.

A phase 3, randomized, double-blind, parallel-group study to evaluate tezacaftor/ivacaftor in people with cystic fibrosis heterozygous for F508del-CFTR and a gating mutation

BACKGROUND

Tezacaftor (TEZ)/ivacaftor (IVA) is an approved CFTR modulator shown to be efficacious and generally safe and well tolerated in people ≥12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous for the F508del-CFTR mutation and a residual function mutation. Although previous studies with IVA alone showed clinical benefits in people with CFTR gating mutations, TEZ/IVA has not yet been evaluated in a Phase 3 study of participants heterozygous for F508del-CFTR and a gating mutation (F/gating genotypes). Here, we present results from a randomized, double-blind, IVA-controlled, parallel-group, Phase 3 study assessing the efficacy, safety, and pharmacokinetics (PK) of TEZ/IVA in participants ≥12 years of age with F/gating genotypes.

METHODS

Enrolled participants entered a 4-week IVA run-in period to create a stable IVA baseline. Participants were then randomized to receive IVA or TEZ/IVA for 8 weeks in an active comparator treatment period (ACTP). The primary endpoint was absolute change in percent predicted forced expiratory volume in 1 second (ppFEV₁). Key secondary endpoints were relative change in ppFEV₁ and absolute change in CF Questionnaire-Revised respiratory domain score. Secondary endpoints included absolute change in sweat chloride (SwCl) concentration, PK parameters, and safety. All endpoints except PK parameters and safety were assessed from baseline through Week 8.

RESULTS

Sixty-nine participants (92.0%) in the IVA group and 75 participants (98.7%) in the TEZ/IVA group completed treatment. No improvements were seen in efficacy endpoints from baseline at the end of the IVA run-in period through the end of the ACTP in the IVA group. No significant differences in ppFEV₁ or any key secondary endpoint were observed between the IVA and TEZ/IVA groups. SwCl concentrations decreased more in the TEZ/IVA versus IVA group during the ACTP. The safety profile and PK parameters of TEZ/IVA were consistent with those of previous studies in participants ≥12 years of age with CF.

CONCLUSIONS

This Phase 3 study showed that the dual-combination regimen of TEZ/IVA demonstrated clinical efficacy but did not have significantly greater clinical efficacy than IVA alone in participants ≥12 years of age with F/gating genotypes. However, as reported in other studies, TEZ/IVA was generally safe and well tolerated (NCT02412111).

A phase 3, double-blind, parallel-group study to evaluate the efficacy and safety of tezacaftor in combination with ivacaftor in participants 6 through 11 years of age with cystic fibrosis homozygous for F508del or heterozygous for the F508del-CFTR mutation and a residual function mutation

BACKGROUND

The CFTR modulator tezacaftor/ivacaftor was efficacious and generally safe and well tolerated in Phase 3 studies in participants ≥12 years of age with cystic fibrosis (CF) homozygous for the F508del-CFTR mutation or heterozygous with a residual function-CFTR mutation (F/F or F/RF respectively). We evaluated tezacaftor/ivacaftor's efficacy and safety over 8 weeks in participants 6 through 11 years of age with these mutations.

METHODS

Participants were randomized 4:1 to tezacaftor/ivacaftor or a blinding group (placebo for F/F, ivacaftor for F/RF). The primary endpoint was within-group change from baseline in the lung clearance index 2·5 (LCI_2·5) through Week 8. Secondary endpoints were change from baseline in sweat chloride (SwCl), cystic fibrosis questionnaire-revised (CFQ-R) respiratory domain score, and safety.

RESULTS

Sixty-seven participants received at least one study drug dose. Of those, 54 received tezacaftor/ivacaftor (F/F, 42; F/RF, 12), 10 placebo, and 3 ivacaftor; 66 completed the study. The within-group change in LCI_2·5 was significantly reduced (improved) by -0·51 (95% CI: -0·74, -0·29). SwCl concentration decreased (improved) by -12·3 mmol/L and CFQ-R respiratory domain score increased (improved, nonsignificantly) by 2·3 points. There were no serious adverse events (AEs) or AEs leading to tezacaftor/ivacaftor discontinuation or interruption. The most common AEs (≥10%) in participants receiving tezacaftor/ivacaftor were cough, headache, and productive cough.

CONCLUSIONS

Tezacaftor/ivacaftor improved lung function (assessed using LCI) and CFTR function (measured by SwCl concentration) in participants 6 through 11 years of age with F/F or F/RF genotypes. Tezacaftor/ivacaftor was safe and well tolerated; no new safety concerns were identified.

ADAM15 expression is increased in lung CD8+ T cells, macrophages, and bronchial epithelial cells in patients with COPD and is inversely related to airflow obstruction

BACKGROUND

A disintegrin and metalloproteinase domain-15 (ADAM15) is expressed by activated leukocytes, and fibroblasts in vitro. Whether ADAM15 expression is increased in the lungs of COPD patients is not known.

METHODS

ADAM15 gene expression and/or protein levels were measured in whole lung and bronchoalveolar lavage (BAL) macrophage samples obtained from COPD patients, smokers, and non-smokers. Soluble ADAM15 protein levels were measured in BAL fluid (BALF) and plasma samples from COPD patients and controls. Cells expressing ADAM15 in the lungs were identified using immunostaining. Staining for ADAM15 in different cells in the lungs was related to forced expiratory volume in 1 s (FEV1), ratio of FEV1 to forced vital capacity (FEV1/FVC), and pack-years of smoking history.

RESULTS

ADAM15 gene expression and/or protein levels were increased in alveolar macrophages and whole lung samples from COPD patients versus smokers and non-smokers. Soluble ADAM15 protein levels were similar in BALF and plasma samples from COPD patients and controls. ADAM15 immunostaining was increased in macrophages, CD8+ T cells, epithelial cells, and airway α-smooth muscle (α-SMA)-positive cells in the lungs of COPD patients. ADAM15 immunostaining in macrophages, CD8+ T cells and bronchial (but not alveolar) epithelial cells was related inversely to FEV1 and FEV1/FVC, but not to pack-years of smoking history. ADAM15 staining levels in airway α-SMA-positive cells was directly related to FEV1/FVC. Over-expressing ADAM15 in THP-1 cells reduced their release of matrix metalloproteinases and CCL2.

CONCLUSIONS

These results link increased ADAM15 expression especially in lung leukocytes and bronchial epithelial cells to the pathogenesis of COPD.

Tezacaftor/ivacaftor in people with cystic fibrosis heterozygous for minimal function CFTR mutations

BACKGROUND

Tezacaftor/ivacaftor is a CFTR modulator approved to treat people with cystic fibrosis (pwCF) who are homozygous (F/F) or heterozygous for the F508del-CFTR mutation and a residual function mutation (F/RF). This randomized, double-blind, placebo-controlled Phase 3 study evaluated the efficacy, safety, tolerability, and pharmacokinetics (PK) of tezacaftor/ivacaftor in participants ≥12 years of age heterozygous for the F508del-CFTR mutation and a minimal function mutation (F/MF), which produces no CFTR protein or a protein unresponsive to tezacaftor/ivacaftor in vitro.

METHODS

Participants were randomized 1:1 to receive tezacaftor/ivacaftor or placebo for 12 weeks. The primary endpoint was the absolute change from baseline in percent predicted forced expiratory volume in 1 second (ppFEV₁) between the tezacaftor/ivacaftor and placebo groups through week 12. Key secondary endpoints included absolute change from baseline in CF Questionnaire-Revised respiratory domain scores and the number of pulmonary exacerbations through week 12 and the absolute change from baseline in body mass index at week 12. A prespecified interim analysis (IA) for futility was conducted when approximately 50% of a planned enrollment of 300 participants reached week 12 of the study.

RESULTS

At the time of the IA, 83 participants were randomized to tezacaftor/ivacaftor and 85 to placebo; 165 participants completed treatment. The study failed to demonstrate that tezacaftor/ivacaftor significantly improved ppFEV₁ or any of the key secondary endpoints and was terminated for futility. The safety profile and PK parameters of tezacaftor/ivacaftor were similar to those reported in prior studies in participants ≥12 years of age with CF.

CONCLUSIONS

Tezacaftor/ivacaftor did not show a clinically meaningful benefit in participants with F/MF genotypes but was generally safe and well tolerated, consistent with the safety profile reported in other Phase 3 studies (NCT02516410).

ADAM (a Disintegrin and Metalloproteinase) 15 Deficiency Exacerbates Ang II (Angiotensin II)-Induced Aortic Remodeling Leading to Abdominal Aortic Aneurysm

Supplemental Digital Content is available in the text.

Objective:

ADAM (a disintegrin and metalloproteinase) 15—a membrane-bound metalloprotease from the ADAM (disintegrin and metalloproteinase) family—has been linked to endothelial permeability, inflammation, and metastasis. However, its function in aortic aneurysm has not been explored. We aimed to determine the function of ADAM15 in the pathogenesis of aortic remodeling and aneurysm formation.

Approach and Results:

Male Adam15-deficient and WT (wild type) mice (10 weeks old), on standard laboratory diet, received Ang II (angiotensin II; 1.5 mg/kg per day) or saline (Alzet pump) for 2 or 4 weeks. Ang II increased ADAM15 in WT aorta, while Adam15-deficiency resulted in abdominal aortic aneurysm characterized by loss of medial smooth muscle cells (SMCs), elastin fragmentation, inflammation, but unaltered Ang II–mediated hypertension. In the abdominal aortic tissue and primary aortic SMCs culture, Adam15 deficiency decreased SMC proliferation, increased apoptosis, and reduced contractile properties along with F-actin depolymerization to G-actin. Ang II triggered a markedly greater increase in THBS (thrombospondin) 1 in Adam15-deficient aorta, primarily the medial layer in vivo, and in aortic SMC in vitro; increased SSH1 (slingshot homolog 1) phosphatase activity and cofilin dephosphorylation that promoted F-actin depolymerization and G-actin accumulation. rhTHBS1 (recombinant THBS1) alone was sufficient to activate the cofilin pathway, increase G-actin, and induce apoptosis of aortic SMCs, confirming the key role of THBS1 in this process. Further, in human abdominal aortic aneurysm specimens, decreased ADAM15 was associated with increased THBS1 levels and loss of medial SMCs.

Conclusions:

This study is the first to demonstrate a key role for ADAM15 in abdominal aortic aneurysm through regulating the SMC function, thereby placing ADAM15 in a critical position as a potential therapeutic target for abdominal aortic aneurysm.

Plasma metabolomics and clinical predictors of survival differences in COPD patients

BACKGROUND

Plasma metabolomics profile (PMP) in COPD has been associated with clinical characteristics, but PMP's relationship to survival has not been reported. We determined PMP differences between patients with COPD who died an average of 2 years after enrollment (Non-survivors, NS) compared to those who survived (S) and also with age matched controls (C).

METHODS

We studied prospectively 90 patients with severe COPD and 30 controls. NS were divided in discovery and validation cohorts (30 patients each) and the results compared to the PMP of 30 S and C. All participants completed lung function tests, dyspnea scores, quality of life, exercise capacity, BODE index, and plasma metabolomics by liquid and gas chromatography / mass spectometry (LC/MS, LC/MS2, GC/MS). Statistically, we used Random Forest Analysis (RFA) and Support Vector Machine (SVM) to determine metabolites that differentiated the 3 groups and compared the ability of metabolites vs. clinical characteristics to classify patients into survivors and non-survivors.

RESULTS

There were 79 metabolites statistically different between S and NS [p < 0.05 and false discovery rate (q value) < 0.1]. RFA and SVM classification of COPD survivors and non-survivors had a predicted accuracy of 74 and 85% respectively. Elevation of tricyclic acid cycle intermediates branched amino acids depletion and increase in lactate, fructose and xylonate showed the most relevant differences between S vs. NS suggesting alteration in mitochondrial oxidative energy generation. PMP had similar predictive power for risk of death as information provided by clinical characteristics.

CONCLUSIONS

A plasma metabolomic profile characterized by an oxidative energy production difference between survivors and non-survivors was observed in COPD patients 2 years before death.

CFTR regulates B cell activation and lymphoid follicle development

Background

Cystic fibrosis (CF) is an inherited disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that promotes persistent lung infection and inflammation and progressive loss of lung function. Patients with CF have increased lung lymphoid follicles (LFs) and B cell-activating factor of tumor necrosis factor family (BAFF) that regulates B cell survival and maturation. A direct role for CFTR in B cell activation and disease pathogenesis in CF remains unclear.

Methods

The number of LFs, BAFF⁺, TLR4⁺ and proliferation marker Ki67⁺ B cells in lung explants or resections from subjects with CF and normal controls was quantified by immunostaining. The role of CFTR in B cell activation and LF development was then examined in two independent cohorts of uninfected CFTR-deficient mice (Cftr^−/−) and wild type controls. The number of lung LFs, B cells and BAFF⁺, CXCR4⁺, immunoglobulin G⁺ B cells was examined by immunostaining. Lung and splenocyte B cell activation marker and major histocompatibility complex class II (MHC class II) expression was quantified by flow cytometry. Inflammatory cytokine levels were measured in supernatants from isolated B cells from Cftr^−/− and wild type mice stimulated in vitro with Pseudomonas aeruginosa lipopolysaccharide (LPS).

Results

There was a significant increase in well-formed LFs in subjects with CF compared to normal controls. Increased B cell activation and proliferation was observed in lung LFs from CF subjects as was quantified by a significant increase in B cell BAFF, TLR4 and Ki67 expression. Uninfected Cftr^−/− mice had increased lung LFs and BAFF⁺ and CXCR4⁺ B cells compared to wild type controls. Lung B cells isolated from uninfected Cftr^−/− mice demonstrated increased MHC class II expression. In vitro, isolated B cells from Cftr^−/− mice produced increased IL-6 when stimulated with LPS compared to wild type controls.

Conclusions

These data support a direct role for CFTR in B cell activation, proliferation and inflammatory cytokine production that promotes lung LF follicle development in cystic fibrosis.

A phase 3 study of tezacaftor in combination with ivacaftor in children aged 6 through 11 years with cystic fibrosis

BACKGROUND

Tezacaftor/ivacaftor is a new treatment option in many regions for patients aged ≥12 years who are homozygous (F/F) or heterozygous for the F508del-CFTR mutation and a residual function (F/RF) mutation. This Phase 3, 2-part, open-label study evaluated the pharmacokinetics (PK), safety, tolerability, and efficacy of tezacaftor/ivacaftor in children aged 6 through 11 years with these mutations.

METHODS

Part A informed weight-based tezacaftor/ivacaftor dosages for part B. The primary objective of part B was to evaluate the safety and tolerability of tezacaftor/ivacaftor through 24 weeks; the secondary objective was to evaluate efficacy based on changes from baseline in percentage predicted forced expiratory volume in 1 s (ppFEV₁), growth parameters, sweat chloride, and the Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain score.

RESULTS

After PK analysis in part A, 70 children received ≥1 dose of tezacaftor/ivacaftor in part B; 67 children completed treatment. Exposures in children aged 6 through 11 years were within the target range for those observed in patients aged ≥12 years. The safety profile of tezacaftor/ivacaftor was generally similar to prior studies in patients aged ≥12 years. One child discontinued treatment for a serious adverse event of constipation. Tezacaftor/ivacaftor treatment improved sweat chloride levels and CFQ-R respiratory domain scores, mean ppFEV₁ remained stable in the normal range, and growth parameters remained stable over 24 weeks.

CONCLUSIONS

Tezacaftor/ivacaftor was generally safe and well tolerated, and improved CFTR function in children aged 6 through 11 years with CF with F/F and F/RF genotypes, supporting tezacaftor/ivacaftor use in this age group. NCT02953314.

Tissue Inhibitor of Metalloproteinase-1 Promotes Polymorphonuclear Neutrophil (PMN) Pericellular Proteolysis by Anchoring Matrix Metalloproteinase-8 and -9 to PMN Surfaces

Matrix metalloproteinase (MMP)-8 and -9 released by degranulating polymorphonuclear cells (PMNs) promote pericellular proteolysis by binding to PMN surfaces in a catalytically active tissue inhibitor of metalloproteinases (TIMP)-resistant forms. The PMN receptor(s) to which MMP-8 and MMP-9 bind(s) is not known. Competitive binding experiments showed that Mmp-8 and Mmp-9 share binding sites on murine PMN surfaces. A novel form of TIMP-1 (an inhibitor of soluble MMPs) is rapidly expressed on PMN surfaces when human PMNs are activated. Membrane-bound TIMP-1 is the PMN receptor for pro- and active MMP-8 and -9 as shown by the following: 1) TIMP-1 is strikingly colocalized with MMP-8 and -9 on activated human PMN surfaces and in PMN extracellular traps; 2) minimal immunoreactive and active Mmp-8 or Mmp-9 are detected on the surface of activated Timp-1^-/- murine PMNs; and 3) binding of exogenous Timp-1 (but not Timp-2) to Timp-1^-/- murine PMNs reconstitutes the binding of exogenous pro-Mmp-8 and pro-Mmp-9 to the surface of Timp-1^-/- PMNs. Unlike full-length pro-Mmp-8 and pro-Mmp-9, mutant pro-Mmp proteins lacking the COOH-terminal hemopexin domain fail to bind to Mmp-8^-/-x Mmp-9^-/- murine PMNs. Soluble hemopexin inhibits the binding of pro-Mmp-8 and pro-Mmp-9 to Mmp-8^-/-x Mmp-9^-/- murine PMNs. Thus, the COOH-terminal hemopexin domains of pro-Mmp-8 and pro-Mmp-9 are required for their binding to membrane-bound Timp-1 on murine PMNs. Exposing nonhuman primates to cigarette smoke upregulates colocalized expression of TIMP-1 with MMP-8 and MMP-9 on peripheral blood PMN surfaces. By anchoring MMP-8 and MMP-9 to PMN surfaces, membrane-bound TIMP-1 plays a counterintuitive role in promoting PMN pericellular proteolysis occurring in chronic obstructive pulmonary disease and other diseases.

RNA-sequencing across three matched tissues reveals shared and tissue-specific gene expression and pathway signatures of COPD

BACKGROUND

Multiple gene expression studies have been performed separately in peripheral blood, lung, and airway tissues to study COPD. We performed RNA-sequencing gene expression profiling of large-airway epithelium, alveolar macrophage and peripheral blood samples from the same subset of COPD cases and controls from the COPDGene study who underwent bronchoscopy at a single center. Using statistical and gene set enrichment approaches, we sought to improve the understanding of COPD by studying gene sets and pathways across these tissues, beyond the individual genomic determinants.

METHODS

We performed differential expression analysis using RNA-seq data obtained from 63 samples from 21 COPD cases and controls (includes four non-smokers) via the R package DESeq2. We tested associations between gene expression and variables related to lung function, smoking history, and CT scan measures of emphysema and airway disease. We examined the correlation of differential gene expression across the tissues and phenotypes, hypothesizing that this would reveal preserved and private gene expression signatures. We performed gene set enrichment analyses using curated databases and findings from prior COPD studies to provide biological and disease relevance.

RESULTS

The known smoking-related genes CYP1B1 and AHRR were among the top differential expression results for smoking status in the large-airway epithelium data. We observed a significant overlap of genes primarily across large-airway and macrophage results for smoking and airway disease phenotypes. We did not observe specific genes differentially expressed in all three tissues for any of the phenotypes. However, we did observe hemostasis and immune signaling pathways in the overlaps across all three tissues for emphysema, and amyloid and telomere-related pathways for smoking. In peripheral blood, the emphysema results were enriched for B cell related genes previously identified in lung tissue studies.

CONCLUSIONS

Our integrative analyses across COPD-relevant tissues and prior studies revealed shared and tissue-specific disease biology. These replicated and novel findings in the airway and peripheral blood have highlighted candidate genes and pathways for COPD pathogenesis.

Macrophage FABP4 is required for neutrophil recruitment and bacterial clearance in Pseudomonas aeruginosa pneumonia

Fatty acid binding protein 4 (FABP4), an intracellular lipid chaperone and adipokine, is expressed by lung macrophages, but the function of macrophage-FABP4 remains elusive. We investigated the role of FABP4 in host defense in a murine model of Pseudomonas aeruginosa pneumonia. Compared with wild-type (WT) mice, FABP4-deficient (FABP4-/-) mice exhibited decreased bacterial clearance and increased mortality when challenged intranasally with P. aeruginosa. These findings in FABP4-/- mice were associated with a delayed neutrophil recruitment into the lungs and were followed by greater acute lung injury and inflammation. Among leukocytes, only macrophages expressed FABP4 in WT mice with P. aeruginosa pneumonia. Chimeric FABP4-/- mice with WT bone marrow were protected from increased mortality seen in chimeric WT mice with FABP4-/- bone marrow during P. aeruginosa pneumonia, thus confirming the role of macrophages as the main source of protective FABP4 against that infection. There was less production of C-X-C motif chemokine ligand 1 (CXCL1) in FABP4-/- alveolar macrophages and lower airway CXCL1 levels in FABP4-/- mice. Delivering recombinant CXCL1 to the airways protected FABP4-/- mice from increased susceptibility to P. aeruginosa pneumonia. Thus, macrophage-FABP4 has a novel role in pulmonary host defense against P. aeruginosa infection by facilitating crosstalk between macrophages and neutrophils via regulation of macrophage CXCL1 production.-Liang, X., Gupta, K., Rojas Quintero, J., Cernadas, M., Kobzik, L., Christou, H., Pier, G. B., Owen, C. A., Çataltepe, S. Macrophage FABP4 is required for neutrophil recruitment and bacterial clearance in Pseudomonas aeruginosa pneumonia.

Club Cell Secretory Protein Deficiency Leads to Altered Lung Function

RATIONALE

CC16 (club cell secretory protein-16), a member of the secretoglobin family, is one of the most abundant proteins in normal airway secretions and has been described as a serum biomarker for obstructive lung diseases.

OBJECTIVES

To determine whether low CC16 is a marker for airway pathology or is implicated in the pathophysiology of progressive airway damage in these conditions.

METHODS

Using human data from the birth cohort of the Tucson Children's Respiratory Study, we examined the relation of circulating CC16 levels with pulmonary function and responses to bronchial methacholine challenge from childhood up to age 32 years. In wild-type and CC16-/- mice, we set out to comprehensively examine pulmonary physiology, inflammation, and remodeling in the naive airway.

MEASUREMENTS AND MAIN RESULTS

We observed that Tucson Children's Respiratory Study participants in the lowest tertile of serum CC16 had significant deficits in their lung function and enhanced airway hyperresponsiveness to methacholine challenge from 11 years throughout young adult life. Similarly, CC16-/- mice had significant deficits in lung function and enhanced airway hyperresponsiveness to methacholine as compared with wild-type mice, which were independent of inflammation and mucin production. As compared with wild-type mice, CC16-/- mice had significantly elevated gene expression of procollagen type I, procollagen type III, and α-smooth muscle actin, areas of pronounced collagen deposition and significantly enhanced smooth muscle thickness.

CONCLUSIONS

Our findings support clinical observations by providing evidence that lack of CC16 in the lung results in dramatically altered pulmonary function and structural alterations consistent with enhanced remodeling.

Matrix metalloproteinase-9 deficiency protects mice from severe influenza A viral infection

Matrix metalloproteinase-9 (MMP-9) cleaves various proteins to regulate inflammatory and injury responses. However, MMP-9's activities during influenza A viral (IAV) infections are incompletely understood. Herein, plasma MMP-9 levels were increased in patients with pandemic H1N1 and seasonal IAV infections. MMP-9 lung levels were increased and localized to airway epithelial cells and leukocytes in H1N1-infected WT murine lungs. H1N1-infected Mmp-9-/- mice had lower mortality rates, reduced weight loss, lower lung viral titers, and reduced lung injury, along with lower E-cadherin shedding in bronchoalveolar lavage fluid (BALF) samples than WT mice. H1N1-infected Mmp-9-/- mice had an altered immune response to IAV with lower BALF PMN and macrophage counts, higher Th1-like CD4+ and CD8+ T cell subsets, lower T regulatory cell counts, reduced lung type I interferon levels, and higher lung interferon-γ levels. Mmp-9 bone marrow-chimera studies revealed that Mmp-9 deficiency in lung parenchymal cells protected mice from IAV-induced mortality. H1N1-infected Mmp-9-/- lung epithelial cells had lower viral titers than H1N1-infected WT cells in vitro. Thus, H1N1-infected Mmp-9-/- mice are protected from IAV-induced lung disease due to a more effective adaptive immune response to IAV and reduced epithelial barrier injury due partly to reduced E-cadherin shedding. Thus, we believe that MMP-9 is a novel therapeutic target for IAV infections.

A Disintegrin and Metalloproteinase Domain-8: A Novel Protective Proteinase in Chronic Obstructive Pulmonary Disease

RATIONALE

ADAM8 (a disintegrin and metalloproteinase domain-8) is expressed by leukocytes and epithelial cells in health, but its contribution to the pathogenesis of chronic obstructive pulmonary disease (COPD) is unknown.

OBJECTIVES

To determine whether the expression of ADAM8 is increased in the lungs of patients with COPD and cigarette smoke (CS)-exposed mice, and whether ADAM8 promotes the development of COPD.

METHODS

ADAM8 levels were measured in lung, sputum, plasma, and/or BAL fluid samples from patients with COPD, smokers, and nonsmokers, and wild-type (WT) mice exposed to CS versus air. COPD-like lung pathologies were compared in CS-exposed WT versus Adam8-/- mice.

MEASUREMENTS AND MAIN RESULTS

ADAM8 immunostaining was reduced in macrophages, and alveolar and bronchial epithelial cells in the lungs of patients with COPD versus control subjects, and CS- versus air-exposed WT mice. ADAM8 levels were similar in plasma, sputum, and BAL fluid samples from patients with COPD and control subjects. CS-exposed Adam8-/- mice had greater airspace enlargement and airway mucus cell metaplasia than WT mice, but similar small airway fibrosis. CS-exposed Adam8-/- mice had higher lung macrophage counts, oxidative stress levels, and alveolar septal cell death rates, but lower alveolar septal cell proliferation rates and soluble epidermal growth factor receptor BAL fluid levels than WT mice. Adam8 deficiency increased lung inflammation by reducing CS-induced activation of the intrinsic apoptosis pathway in macrophages. Human ADAM8 proteolytically shed the epidermal growth factor receptor from bronchial epithelial cells to reduce mucin expression in vitro. Adam8 bone marrow chimera studies revealed that Adam8 deficiency in leukocytes and lung parenchymal cells contributed to the exaggerated COPD-like disease in Adam8-/- mice.

CONCLUSIONS

Adam8 deficiency increases CS-induced lung inflammation, emphysema, and airway mucus cell metaplasia. Strategies that increase or prolong ADAM8's expression in the lung may have therapeutic efficacy in COPD.

Beclin-1 regulates cigarette smoke-induced kidney injury in a murine model of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD), associated with cigarette smoke-induced (CS-induced) emphysema, contributes significantly to the global health care burden of disease. Although chronic kidney disease (CKD) may occur in patients with COPD, the relationship between COPD and CKD remains unclear. Using a murine model of experimental COPD, we show that chronic CS exposure resulted in marked kidney injury and fibrosis, as evidenced by histological and ultrastructural changes, altered macrophage subpopulations, and expression of tissue injury, fibrosis, and oxidative stress markers. CS induced mitochondrial dysfunction, and increased autophagic flux in kidney tissues and in kidney tubular epithelial (HK-2) cells, as determined by LC3B turnover assays. Mice heterozygous for Beclin-1 (Becn1+/-) were protected from the development of kidney tissue injury and renal fibrosis in response to CS exposure, and displayed impaired basal and inducible mitochondrial turnover by mitophagy. Interestingly, CS caused a reduction of Beclin-1 expression in mouse kidneys and kidney tubular epithelial cells, attributed to increased autophagy-dependent turnover of Beclin-1. These results suggest that Beclin-1 is required for CS-induced kidney injury and that reduced levels of Beclin-1 may confer renoprotection. These results identify the kidney as a target for CS-induced injury in COPD and the Beclin-1-dependent autophagy pathway as a potential therapeutic target in CKD.

Club cell protein 16 (Cc16) deficiency increases inflamm-aging in the lungs of mice

Low serum CC16 levels are associated with accelerated lung function decline in human population studies, but it is not known whether low serum CC16 levels contribute to lung function decline, or are an epiphenomenon. We tested the hypothesis that unchallenged Cc16-/- mice develop accelerated rates of pulmonary function test abnormalities and pulmonary pathologies over time compared with unchallenged WT mice. Respiratory mechanics, airspace enlargement, and small airway fibrosis were measured in unchallenged wild-type (WT) versus Cc16-/- mice over 6-18 months of age. Lung leukocyte counts and lung levels of metalloproteinases (Mmps), cytokines, oxidative stress, cellular senescence markers (p19 and p21), and lung cell apoptosis, and serum C-reactive protein (CRP) levels were measured in age-matched WT versus Cc16-/- mice. Unchallenged Cc16-/- mice developed greater increases in lung compliance, airspace enlargement, and small airway fibrosis than age-matched WT mice over 6-18 months of age. Cc16-/- mice had greater: (1) lung leukocyte counts; (2) lung levels of Ccl2, Ccl-5, interleukin-10, Mmp-2, and Mmp-9; (3) pulmonary oxidative stress levels, (4) alveolar septal cell apoptosis and staining for p16 and p21; and (5) serum CRP levels. Unchallenged Cc16-/- mice had greater nuclear factor-κB (NF-κB) activation in their lungs than age-matched WT mice, but similar lung levels of secretory phospholipase-A2 activity. Cc16 deficiency in mice leads spontaneously to an accelerated lung aging phenotype with exaggerated pulmonary inflammation and COPD-like lung pathologies associated with increased activation of NF- κB in the lung. CC16 augmentation strategies may reduce lung aging in CC16-deficient individuals.

A Disintegrin and A Metalloproteinase-9 (ADAM9): A Novel Proteinase Culprit with Multifarious Contributions to COPD

INTRODUCTION

Proteinases with a disintegrin and a metalloproteinase domain (ADAMs) have not been well studied in COPD. We investigated whether ADAM9 is linked to COPD in humans and mice.

METHODS

ADAM9 blood and lung levels were measured in COPD patients versus controls, and air- versus cigarette smoke (CS)-exposed wild-type (WT) mice. WT and Adam9-/- mice were exposed to air or CS for 1-6 months, and COPD-like lung pathologies were measured.

RESULTS

ADAM9 staining was increased in lung epithelial cells and macrophages in smokers and even more so in COPD patients and correlated directly with pack-year smoking history and inversely with airflow obstruction and/or FEV1 % predicted. Bronchial epithelial cell ADAM9 mRNA levels were higher in COPD patients than controls and correlated directly with pack-year smoking history. Plasma, BALF and sputum ADAM9 levels were similar in COPD patients and controls. CS exposure increased Adam9 levels in WT murine lungs. Adam9-/- mice were protected from emphysema development, small airway fibrosis, and airway mucus metaplasia. CS-exposed Adam9-/- mice had reduced lung macrophage counts, alveolar septal cell apoptosis, lung elastin degradation, and shedding of VEGFR2 and EGFR in BALF samples. Recombinant ADAM9 sheds EGF and VEGF receptors from epithelial cells to reduce activation of the Akt pro-survival pathway and increase cellular apoptosis.

CONCLUSIONS

ADAM9 levels are increased in COPD lungs and linked to key clinical variables. Adam9 promotes emphysema development, and large and small airway disease in mice. Inhibition of ADAM9 could be a therapeutic approach for multiple COPD phenotypes.

Gas exchange and breathing pattern in women with postmenopausal bone fragility

BACKGROUND

Little is known about the relationship between bone fragility and respiratory function. We hypothesized that women with osteoporosis or osteopenia, without cardio-pulmonary disease, have perturbations in the pattern of breathing and gas exchange.

METHODS

In 44 women with bone fragility (BF, T score: < -1), and 20 anthropomorphically-matched control women (T score > -1) we compared pulmonary function tests, central respiratory drive (mouth occlusion pressure or P 0.1), pattern of breathing using optoelectronic plethysmograph and arterial blood gases at rest.

RESULTS

Static pulmonary function was similar in BF subjects and controls. However, the arterial blood gas measurements differed significantly. The arterial pH was significantly higher in BF subjects than in controls (P < 0.001). The partial pressure of carbon dioxide (PaCO₂) and oxygen (PaO₂) in arterial blood were significantly lower in BF subjects than controls (P < 0.001 and P = 0.009, respectively). The BF subjects had a shorter inspiratory fraction compared with controls (P = 0.036). Moreover, T-scores were significantly inversely correlated with the alveolar-arterial gradient of oxygen (r = -0.5; P = 0.0003) and the arterial pH (r = -0.4; P = 0.002), and positively correlated with arterial PaO₂ (r = 0.3; P = 0.01) and PaCO₂ (r = 0.4; P = 0.002) among all subjects.

CONCLUSION

In the absence of known cardio-pulmonary disease, BF is associated with statistically significant perturbations in gas exchange and alterations in the pattern of breathing including shortening of the inspiratory time.

Emphysema and extrapulmonary tissue loss in COPD: a multi-organ loss of tissue phenotype

We tested whether emphysema progression accompanies enhanced tissue loss in other body compartments in 1817 patients from the ECLIPSE chronic obstructive pulmonary disease (COPD) cohort.Clinical and selected systemic biomarker measurements were compared in subjects grouped by quantitative tomography scan emphysema quartiles using the percentage of low attenuation area (LAA%). Lowest and highest quartile patients had amino-acid metabolomic profiles. We related LAA% to 3 years decline in lung function (forced expiratory volume in 1 s (FEV₁)), body mass index (BMI), fat-free mass index (FFMI) and exacerbations, hospitalisations and mortality rates.Participants with more baseline emphysema had lower FEV₁, BMI and FFMI, worse functional capacity, and less cardiovascular disease but more osteoporosis. Systemic C-reactive protein and interleukin-6 levels were similar among groups, but club cell protein 16 was higher and interleukin-8, surfactant protein D and soluble receptor for advanced glycation end product were lower with more emphysema. Metabolomics differed between extreme emphysema quartiles. Patients with more emphysema had accelerated FEV₁, BMI and FFMI decline and more exacerbations, hospitalisations and mortality.COPD patients with more emphysema undergo excessive loss of pulmonary and extrapulmonary tissue, which is probably related to abnormal tissue maintenance. Because of worse clinical outcomes, we propose this subgroup be named the multi-organ loss of tissue (MOLT) COPD phenotype.

COPD as an endothelial disorder: endothelial injury linking lesions in the lungs and other organs? (2017 Grover Conference Series)

Chronic obstructive pulmonary disease (COPD) is characterized by chronic expiratory airflow obstruction that is not fully reversible. COPD patients develop varying degrees of emphysema, small and large airway disease, and various co-morbidities. It has not been clear whether these co-morbidities share common underlying pathogenic processes with the pulmonary lesions. Early research into the pathogenesis of COPD focused on the contributions of injury to the extracellular matrix and pulmonary epithelial cells. More recently, cigarette smoke-induced endothelial dysfunction/injury have been linked to the pulmonary lesions in COPD (especially emphysema) and systemic co-morbidities including atherosclerosis, pulmonary hypertension, and chronic renal injury. Herein, we review the evidence linking endothelial injury to COPD, and the pathways underlying endothelial injury and the "vascular COPD phenotype" including: (1) direct toxic effects of cigarette smoke on endothelial cells; (2) generation of auto-antibodies directed against endothelial cells; (3) vascular inflammation; (4) increased oxidative stress levels in vessels inducing increases in lipid peroxidation and increased activation of the receptor for advanced glycation end-products (RAGE); (5) reduced activation of the anti-oxidant pathways in endothelial cells; (6) increased endothelial cell release of mediators with vasoconstrictor, pro-inflammatory, and remodeling activities (endothelin-1) and reduced endothelial cell expression of mediators that promote vasodilation and homeostasis of endothelial cells (nitric oxide synthase and prostacyclin); and (7) increased endoplasmic reticular stress and the unfolded protein response in endothelial cells. We also review the literature on studies of drugs that inhibit RAGE signaling in other diseases (angiotensin-converting enzyme inhibitors and angiotensin receptor blockers), or vasodilators developed for idiopathic pulmonary arterial hypertension that have been tested on cell culture systems, animal models of COPD, and/or smokers and COPD patients.

Asthma COPD Overlap Syndrome: An Approach to A Real -World Endotype in Obstructive Lung Disease?

BACKGROUND

Although some patients with obstructive lung disease (OLD) have features of both asthma and chronic obstructive pulmonary disease (COPD), the term "asthma-COPD overlap syndrome (ACOS)" was coined only relatively recently. However, there are gaps in our knowledge of the clinical features, pathogenesis, prognosis, and management of ACOS patients.

OBJECTIVES

To review the literature on ACOS to determine the extent to which the clinical features, pathologic mechanisms, clinical outcomes, and current therapeutic approaches for ACOS differ from those in patients with asthma alone or COPD alone.

METHODS

PUBMED searches were conducted to review the demographic and clinical features, comorbidities, lung imaging characteristics, prognoses, pathologic mechanisms, and current therapeutic approaches for patients with ACOS versus asthma alone or COPD alone.

RESULTS

Criteria that are used to diagnose ACOS vary considerably. Overall, ACOS patients have higher symptom burdens (especially dyspnea), poorer quality of life scores, and more frequent and severe exacerbations than patients with COPD alone or asthma alone. However, there are conflicting reports on the prognosis of ACOS patients. Imaging studies indicate that ACOS is predominantly an airway disease. ACOS has been linked to the presence of Th2-type immune responses in COPD airways and Th1-type immune responses in asthmatic airways. Current therapeutic options for ACOS patients include inhaled corticosteroids and bronchodilators. However, randomized clinical trials have not yet been conducted to optimize the management of ACOS patients.

CONCLUSION

ACOS patients have clinical features that are now well defined, but additional studies are needed to provide novel insights into ACOS pathogenesis, and to optimize the treatment of these patients.

Transcriptomic Analysis of Lung Tissue from Cigarette Smoke-Induced Emphysema Murine Models and Human Chronic Obstructive Pulmonary Disease Show Shared and Distinct Pathways

Although cigarette smoke (CS) is the primary risk factor for chronic obstructive pulmonary disease (COPD), the underlying molecular mechanisms for the significant variability in developing COPD in response to CS are incompletely understood. We performed lung gene expression profiling of two different wild-type murine strains (C57BL/6 and NZW/LacJ) and two genetic models with mutations in COPD genome-wide association study genes (HHIP and FAM13A) after 6 months of chronic CS exposure and compared the results to human COPD lung tissues. We identified gene expression patterns that correlate with severity of emphysema in murine and human lungs. Xenobiotic metabolism and nuclear erythroid 2-related factor 2-mediated oxidative stress response were commonly regulated molecular response patterns in C57BL/6, Hhip^+/-, and Fam13a^-/- murine strains exposed chronically to CS. The CS-resistant Fam13a^-/- mouse and NZW/LacJ strain revealed gene expression response pattern differences. The Fam13a^-/- strain diverged in gene expression compared with C57BL/6 control only after CS exposure. However, the NZW/LacJ strain had a unique baseline expression pattern, enriched for nuclear erythroid 2-related factor 2-mediated oxidative stress response and xenobiotic metabolism, and converged to a gene expression pattern similar to the more susceptible wild-type C57BL/6 after CS exposure. These results suggest that distinct molecular pathways may account for resistance to emphysema. Surprisingly, there were few genes commonly modulated in mice and humans. Our study suggests that gene expression responses to CS may be largely species and model dependent, yet shared pathways could provide biologically significant insights underlying individual susceptibility to CS.

A Pilot Study Linking Endothelial Injury in Lungs and Kidneys in Chronic Obstructive Pulmonary Disease

RATIONALE

Patients with chronic obstructive pulmonary disease (COPD) frequently have albuminuria (indicative of renal endothelial cell injury) associated with hypoxemia.

OBJECTIVES

To determine whether (1) cigarette smoke (CS)-induced pulmonary and renal endothelial cell injury explains the association between albuminuria and COPD, (2) CS-induced albuminuria is linked to increases in the oxidative stress-advanced glycation end products (AGEs) receptor for AGEs (RAGE) pathway, and (3) enalapril (which has antioxidant properties) limits the progression of pulmonary and renal injury by reducing activation of the AGEs-RAGE pathway in endothelial cells in both organs.

METHODS

In 26 patients with COPD, 24 ever-smokers without COPD, 32 nonsmokers who underwent a renal biopsy or nephrectomy, and in CS-exposed mice, we assessed pathologic and ultrastructural renal lesions, and measured urinary albumin/creatinine ratios, tissue oxidative stress levels, and AGEs and RAGE levels in pulmonary and renal endothelial cells. The efficacy of enalapril on pulmonary and renal lesions was assessed in CS-exposed mice.

MEASUREMENTS AND MAIN RESULTS

Patients with COPD and/or CS-exposed mice had chronic renal injury, increased urinary albumin/creatinine ratios, and increased tissue oxidative stress and AGEs-RAGE levels in pulmonary and renal endothelial cells. Treating mice with enalapril attenuated CS-induced increases in urinary albumin/creatinine ratios, tissue oxidative stress levels, endothelial cell AGEs and RAGE levels, pulmonary and renal cell apoptosis, and the progression of chronic renal and pulmonary lesions.

CONCLUSIONS

Patients with COPD and/or CS-exposed mice have pulmonary and renal endothelial cell injury linked to increased endothelial cell AGEs and RAGE levels. Albuminuria could identify patients with COPD in whom angiotensin-converting enzyme inhibitor therapy improves renal and lung function by reducing endothelial injury.

Metabolomic profiling in a Hedgehog Interacting Protein (Hhip) murine model of chronic obstructive pulmonary disease

Genetic variants annotated to the hedgehog interacting protein (HHIP) are robustly associated with chronic obstructive pulmonary disease (COPD). Hhip haploinsufficiency in mice leads to increased susceptibility towards the development of emphysema following exposure to chronic cigarette smoke (CS). To explore the molecular pathways which contribute to increased susceptibility, we performed metabolomic profiling using high performance liquid chromatography tandem mass spectroscopy (LC/MS-MS) on plasma, urine, and lung tissue of Hhip^+/− heterozygotes and wild type (Hhip^+/+) C57/BL6 mice exposed to either room-air or CS for six months. Univariate comparisons between groups were made with a combined fold change ≥2 and Student’s t-test p-value < 0.05 to denote significance; associations with mean alveolar chord length (MACL), a quantitative measure of emphysema, and gene-by-environment interactions were examined using empiric Bayes-mediated linear models. Decreased urinary excretion of cotinine despite comparable plasma levels was observed in Hhip^+/− heterozygotes; a strong gene-by-smoking association was also observed. Correlations between MACL and markers of oxidative stress such as urinary methionine sulfoxide were observed in Hhip^+/− but not in Hhip^+/+ mice. Metabolite set enrichment analyses suggest reduced antioxidant capacity and alterations in macronutrient metabolism contribute to increased susceptibility to chronic CS-induced oxidative stress in Hhip haploinsufficiency states.

B cells in chronic obstructive pulmonary disease: moving to center stage

Chronic inflammatory responses in the lungs contribute to the development and progression of chronic obstructive pulmonary disease (COPD). Although research studies focused initially on the contributions of the innate immune system to the pathogenesis of COPD, more recent studies have implicated adaptive immune responses in COPD. In particular, studies have demonstrated increases in B cell counts and increases in the number and size of B cell-rich lymphoid follicles in COPD lungs that correlate directly with COPD severity. There are also increases in lung levels of mediators that promote B cell maturation, activation, and survival in COPD patients. B cell products such as autoantibodies directed against lung cells, components of cells, and extracellular matrix proteins are also present in COPD lungs. These autoantibodies may contribute to lung inflammation and injury in COPD patients, in part, by forming immune complexes that activate complement components. Studies of B cell-deficient mice and human COPD patients have linked B cells most strongly to the emphysema phenotype. However, B cells have protective activities during acute exacerbations of COPD by promoting adaptive immune responses that contribute to host defense against pathogens. This review outlines the evidence that links B cells and B cell-rich lymphoid follicles to the pathogenesis of COPD and the mechanisms involved. It also reviews the potential and limitations of B cells as therapeutic targets to slow the progression of human COPD.

Hhip haploinsufficiency sensitizes mice to age-related emphysema

Genetic variants in Hedgehog interacting protein (HHIP) have consistently been associated with the susceptibility to develop chronic obstructive pulmonary disease and pulmonary function levels, including the forced expiratory volume in 1 s (FEV1), in general population samples by genome-wide association studies. However, in vivo evidence connecting Hhip to age-related FEV1 decline and emphysema development is lacking. Herein, using Hhip heterozygous mice (Hhip(+/-)), we observed increased lung compliance and spontaneous emphysema in Hhip(+/-) mice starting at 10 mo of age. This increase was preceded by increases in oxidative stress levels in the lungs of Hhip(+/-) vs. Hhip(+/+) mice. To our knowledge, these results provide the first line of evidence that HHIP is involved in maintaining normal lung function and alveolar structures. Interestingly, antioxidant N-acetyl cysteine treatment in mice starting at age of 5 mo improved lung function and prevented emphysema development in Hhip(+/-) mice, suggesting that N-acetyl cysteine treatment limits the progression of age-related emphysema in Hhip(+/-) mice. Therefore, reduced lung function and age-related spontaneous emphysema development in Hhip(+/-) mice may be caused by increased oxidative stress levels in murine lungs as a result of haploinsufficiency of Hhip.

A Chronic Obstructive Pulmonary Disease Susceptibility Gene, FAM13A, Regulates Protein Stability of β-Catenin

RATIONALE

A genetic locus within the FAM13A gene has been consistently associated with chronic obstructive pulmonary disease (COPD) in genome-wide association studies. However, the mechanisms by which FAM13A contributes to COPD susceptibility are unknown.

OBJECTIVES

To determine the biologic function of FAM13A in human COPD and murine COPD models and discover the molecular mechanism by which FAM13A influences COPD susceptibility.

METHODS

Fam13a null mice (Fam13a(-/-)) were generated and exposed to cigarette smoke. The lung inflammatory response and airspace size were assessed in Fam13a(-/-) and Fam13a(+/+) littermate control mice. Cellular localization of FAM13A protein and mRNA levels of FAM13A in COPD lungs were assessed using immunofluorescence, Western blotting, and reverse transcriptase-polymerase chain reaction, respectively. Immunoprecipitation followed by mass spectrometry identified cellular proteins that interact with FAM13A to reveal insights on FAM13A's function.

MEASUREMENTS AND MAIN RESULTS

In murine and human lungs, FAM13A is expressed in airway and alveolar type II epithelial cells and macrophages. Fam13a null mice (Fam13a(-/-)) were resistant to chronic cigarette smoke-induced emphysema compared with Fam13a(+/+) mice. In vitro, FAM13A interacts with protein phosphatase 2A and recruits protein phosphatase 2A with glycogen synthase kinase 3β and β-catenin, inducing β-catenin degradation. Fam13a(-/-) mice were also resistant to elastase-induced emphysema, and this resistance was reversed by coadministration of a β-catenin inhibitor, suggesting that FAM13A could increase the susceptibility of mice to emphysema development by inhibiting β-catenin signaling. Moreover, human COPD lungs had decreased protein levels of β-catenin and increased protein levels of FAM13A.

CONCLUSIONS

We show that FAM13A may influence COPD susceptibility by promoting β-catenin degradation.

Therapeutic monoclonal antibodies for respiratory diseases: Current challenges and perspectives, March 31 - April 1, 2016, Tours, France

Monoclonal antibody (mAb) therapeutics have tremendous potential to benefit patients with lung diseases, for which there remains substantial unmet medical need. To capture the current state of mAb research and development in the area of respiratory diseases, the Research Center of Respiratory Diseases (CEPR-INSERM U1100), the Laboratory of Excellence “MAbImprove,” the GDR 3260 “Antibodies and therapeutic targeting,” and the Grant Research program ARD2020 “Biotherapeutics” invited speakers from industry, academic and government organizations to present their recent research results at the Therapeutic Monoclonal Antibodies for Respiratory Diseases: Current challenges and perspectives congress held March 31 – April 1, 2016 in Tours, France.

Increased expression of A Proliferation-Inducing Ligand (APRIL) in lung leukocytes and alveolar epithelial cells in COPD patients with non small cell lung cancer: a possible link between COPD and lung cancer?

Background: Chronic Obstructive Pulmonary Disease (COPD) is characterized by an excessive activation of the adaptive immune system and, in particular, uncontrolled expansion of the B-cell pool. One of the key promoters of B cell expansion is A PRoliferation-Inducing Ligand (APRIL). APRIL has been strongly linked to non small cell lung cancer (NSCLC) onset and progression previously. However, little is known about the expression of APRIL in the lungs of COPD patients. Methods: Using immuno-fluorescence staining, the expression of APRIL was assessed in sections of lungs from 4 subjects with primary diagnosis of COPD (FEV1 33 ± 20 % predicted), 4 subjects with primary diagnosis of NSCLC, 4 subjects diagnosed with both COPD and NSCLC, smokers without COPD or NSCLC and 3 healthy never-smokers. The percentage of B cells, alveolar macrophages (AMs) and polymorphonuclear neutrophils (PMNs) in the lung and alveolar epithelial cells (AECs) that stained positively for APRIL was quantified using epi-fluorescence microscopy and image analysis software. Results: The percentage of APRIL-expressing B cells, AMs, PMNs and alveolar epithelial cells (AECs) was higher in patients having both COPD and NSCLC than in patients with either COPD or NSCLC alone, SC or NSC (p < 0.03 for all comparisons). The percentage of APRIL-expressing AMs and AECs (but not in B cells) was higher in patients with NSCLC alone than in patients with COPD alone. The percentage of APRIL-expressing AECs (but not B cells or AMs) was higher in COPD patients than in SC and NSC (p < 0.05 for all comparisons). The percentage of APRIL-expressing B cells, AMs and AECs cells was similar in NSC and SC. Conclusion: The percentage of APRIL-expressing B cells, AMs and AECs is higher in the lungs of patients with both COPD and NSCLC than in patients with COPD or NSCLC alone or control subjects. These findings suggest that APRIL may contribute to the pathogenesis of both COPD and NSCLC, and possibly to the development of NSCLC in patients with established COPD.