HRD1-mediated METTL14 degradation regulates m6A mRNA modification to suppress ER proteotoxic liver disease.

Accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen triggers an unfolded protein response (UPR) for stress adaptation, the failure of which induces cell apoptosis and tissue/organ damage. The molecular switches underlying how the UPR selects for stress adaptation over apoptosis remain unknown. Here, we discovered that accumulation of unfolded/misfolded proteins selectively induces N6-adenosine-methyltransferase-14 (METTL14) expression. METTL14 promotes C/EBP-homologous protein (CHOP) mRNA decay through its 3' UTR N6-methyladenosine (m6A) to inhibit its downstream pro-apoptotic target gene expression. UPR induces METTL14 expression by competing against the HRD1-ER-associated degradation (ERAD) machinery to block METTL14 ubiquitination and degradation. Therefore, mice with liver-specific METTL14 deletion are highly susceptible to both acute pharmacological and alpha-1 antitrypsin (AAT) deficiency-induced ER proteotoxic stress and liver injury. Further hepatic CHOP deletion protects METTL14 knockout mice from ER-stress-induced liver damage. Our study reveals a crosstalk between ER stress and mRNA m6A modification pathways, termed the ERm6A pathway, for ER stress adaptation to proteotoxicity.

Liver Fibrosis and Metabolic Alterations in Adults With alpha-1-antitrypsin Deficiency Caused by the Pi*ZZ Mutation.

BACKGROUND & AIMS: Alpha-1 antitrypsin deficiency (AATD) is among the most common genetic disorders. Severe AATD is caused by a homozygous mutation in the SERPINA1 gene that encodes the Glu342Lys substitution (called the Pi*Z mutation, Pi*ZZ genotype). Pi*ZZ carriers may develop lung and liver diseases. Mutation-associated lung disorders have been well studied, but less is known about the effects in liver. We assessed the liver disease burden and associated features in adults with this form of AATD. METHODS: We collected data from 554 Pi*ZZ adults (403 in an exploratory cohort, 151 in a confirmatory cohort), in 9 European countries, with AATD who were homozygous for the Pi*Z mutation, and 234 adults without the Pi*Z mutation (controls), all without pre-existing liver disease. We collected data on demographic parameters, comorbidities, lung- and liver-related health, and blood samples for laboratory analysis. Liver fibrosis was assessed non-invasively via the serum tests Aspartate Aminotransferase to Platelet Ratio Index and HepaScore and via transient elastography. Liver steatosis was determined via transient elastography-based controlled attenuation parameter. We performed histologic analyses of livers from transgenic mice that overexpress the AATD-associated Pi*Z variant. RESULTS: Serum levels of liver enzymes were significantly higher in Pi*ZZ carriers vs controls. Based on non-invasive tests for liver fibrosis, significant fibrosis was suspected in 20%-36% of Pi*ZZ carriers, whereas signs of advanced fibrosis were 9- to 20-fold more common in Pi*ZZ carriers compared to non-carriers. Male sex; age older than 50 years; increased levels of alanine aminotransferase, aspartate aminotransferase, or γ-glutamyl transferase; and low numbers of platelets were associated with higher liver fibrosis burden. We did not find evidence for a relationship between lung function and liver fibrosis. Controlled attenuation parameter ≥280 dB/m, suggesting severe steatosis, was detected in 39% of Pi*ZZ carriers vs 31% of controls. Carriers of Pi*ZZ had lower serum concentrations of triglyceride and low- and very-low-density lipoprotein cholesterol than controls, suggesting impaired hepatic secretion of lipid. Livers from Pi*Z-overexpressing mice had steatosis and down-regulation of genes involved in lipid secretion. CONCLUSIONS: In studies of AATD adults with the Pi*ZZ mutation, and of Pi*Z-overexpressing mice, we found evidence of liver steatosis and impaired lipid secretion. We identified factors associated with significant liver fibrosis in patients, which could facilitate hepatologic assessment and counseling of individuals who carry the Pi*ZZ mutation. ClinicalTrials.gov Number NCT02929940.

Blockade of Dopamine D2 Receptors as a Novel Approach to Stimulation of Notch1+ Endothelial Progenitor Cells and Angiogenesis in C57BL/6 Mice with Pulmonary Emphysema Induced by Proteases and Deficiency of α1-Antitrypsin.

We studied the effects of spiperone, a selective blocker of dopamine D2 receptors, on the model of pulmonary emphysema provoked by administration of elastase and D-galactosamine hydrochloride to female C57BL/6 mice and characterized by activation of proteases in the lungs and systemic deficiency of its inhibitor α1-antitrypsin. In this model, spiperone prevented the development of inflammatory reaction and reduced the area of emphysematous expanded alveolar tissue. The expression of angiogenic marker CD31 in the lungs increased under these conditions. Regeneration of the damaged microvascular bed under the action of spiperone resulted from recruiting of Notch1+ endothelial progenitor cells (CD45-CD31+CD34+) into the lungs and blockade of the inhibitory effect of dopamine on phosphorylation of VEGF-2 receptors in endothelial cells of different maturity. In addition, spiperone produced a protective effect on hepatocytes and restored the production and secretion of α1-antitrypsin by these cells.

Survival Advantage of Both Human Hepatocyte Xenografts and Genome-Edited Hepatocytes for Treatment of α-1 Antitrypsin Deficiency.

Hepatocytes represent an important target for gene therapy and editing of single-gene disorders. In α-1 antitrypsin (AAT) deficiency, one missense mutation results in impaired secretion of AAT. In most patients, lung damage occurs due to a lack of AAT-mediated protection of lung elastin from neutrophil elastase. In some patients, accumulation of misfolded PiZ mutant AAT protein triggers hepatocyte injury, leading to inflammation and cirrhosis. We hypothesized that correcting the Z mutant defect in hepatocytes would confer a selective advantage for repopulation of hepatocytes within an intact liver. A human PiZ allele was crossed onto an immune-deficient (NSG) strain to create a recipient strain (NSG-PiZ) for human hepatocyte xenotransplantation. Results indicate that NSG-PiZ recipients support heightened engraftment of normal human primary hepatocytes as compared with NSG recipients. This model can therefore be used to test hepatocyte cell therapies for AATD, but more broadly it serves as a simple, highly reproducible liver xenograft model. Finally, a promoterless adeno-associated virus (AAV) vector, expressing a wild-type AAT and a synthetic miRNA to silence the endogenous allele, was integrated into the albumin locus. This gene-editing approach leads to a selective advantage of edited hepatocytes, by silencing the mutant protein and augmenting normal AAT production, and improvement of the liver pathology.

Long-term clinical outcomes following treatment with alpha 1-proteinase inhibitor for COPD associated with alpha-1 antitrypsin deficiency: a look at the evidence.

Alpha-1 antitrypsin deficiency (AATD) is a common hereditary disorder caused by mutations in the SERPINA1 gene, which encodes alpha-1 antitrypsin (AAT; also known as alpha 1-proteinase inhibitor, A1-PI). An important function of A1-PI in the lung is to inhibit neutrophil elastase, one of various proteolytic enzymes released by activated neutrophils during inflammation. Absence or deficiency of A1-PI leads to an imbalance between elastase and anti-elastase activity, which results in progressive, irreversible destruction of lung tissue, and ultimately the development of chronic obstructive pulmonary disease with early-onset emphysema. AATD is under-diagnosed, patients can experience long delays before obtaining an accurate diagnosis, and the consequences of delayed diagnosis or misdiagnosis can be severe. Currently, A1-PI therapy is the only available treatment that addresses disease etiology in patients with AATD; however, demonstrating clinical efficacy of A1-PI therapy is challenging. In order to show therapeutic efficacy with traditional endpoints such as forced expiratory volume in one second and mortality, large sample sizes and longer duration trials are required. However, AATD is a rare, slow progressive disease, which can take decades to manifest clinically and recruiting sufficient numbers of patients into prolonged placebo-controlled trials remains a significant obstacle. Despite this, the Randomized, placebo-controlled trial of augmentation therapy in Alpha 1-Proteinase Inhibitor Deficiency (RAPID) and RAPID Extension trial, the largest clinical program completed to date, utilized quantitative chest computed tomography as a sensitive and specific measure of the extent of emphysema. Findings from the RAPID/RAPID Extension program definitively confirmed the benefits of A1-PI therapy in slowing disease progression and provided evidence of a disease-modifying effect of A1-PI therapy in patients with AATD. These findings suggest that the early introduction of treatment in patients with severe emphysema-related AATD may delay the time to death, lung transplantation or crippling respiratory complaints. In addition, there is now limited evidence that A1-PI therapy provides a gain of more than five life-years, supporting previous observations based on registry data. With the clinical efficacy of A1-PI therapy now demonstrated, further studies are required to assess long-term outcomes.

Deficiency Mutations of Alpha-1 Antitrypsin. Effects on Folding, Function, and Polymerization.

Misfolding, polymerization, and defective secretion of functional alpha-1 antitrypsin underlies the predisposition to severe liver and lung disease in alpha-1 antitrypsin deficiency. We have identified a novel (Ala336Pro, Baghdad) deficiency variant and characterized it relative to the wild-type (M) and Glu342Lys (Z) alleles. The index case is a homozygous individual of consanguineous parentage, with levels of circulating alpha-1 antitrypsin in the moderate deficiency range, but is a biochemical phenotype that could not be classified by standard methods. The majority of the protein was present as functionally inactive polymer, and the remaining monomer was 37% active relative to the wild-type protein. These factors combined indicate an 85 to 95% functional deficiency, similar to that seen with ZZ homozygotes. Biochemical, biophysical, and computational studies further defined the molecular basis of this deficiency. These studies demonstrated that native Ala336Pro alpha-1 antitrypsin could populate the polymerogenic intermediate-and therefore polymerize-more readily than either wild-type alpha-1 antitrypsin or the Z variant. In contrast, folding was far less impaired in Ala336Pro alpha-1 antitrypsin than in the Z variant. The data are consistent with a disparate contribution by the "breach" region and "shutter" region of strand 5A to folding and polymerization mechanisms. Moreover, the findings demonstrate that, in these variants, folding efficiency does not correlate directly with the tendency to polymerize in vitro or in vivo. They therefore differentiate generalized misfolding from polymerization tendencies in missense variants of alpha-1 antitrypsin. Clinically, they further support the need to quantify loss-of-function in alpha-1 antitrypsin deficiency to individualize patient care.

Autophagy induced by exogenous bile acids is therapeutic in a model of α-1-AT deficiency liver disease.

The bile acid nor-ursodeoxycholic acid (norUDCA) has many biological actions, including antiapoptotic effects. Homozygous PIZZ α-1-antitrypsin (A1AT)-deficient humans are known to be at risk for liver disease, cirrhosis, and liver cancer as a result of the accumulation of the toxic, A1AT mutant Z protein within hepatocytes. This accumulation triggers cell death in the hepatocytes with the largest mutant Z-protein burdens, followed by compensatory proliferation. Proteolysis pathways within the hepatocyte, including autophagy, act to reduce the intracellular burden of A1AT Z protein. We hypothesized that norUDCA would reduce liver cell death and injury in A1AT deficiency. We treated groups of PiZ transgenic mice and wild-type mice with norUDCA or vehicle, orally, and examined the effects on the liver. The PiZ mouse is the best model of A1AT liver injury and recapitulates many features of the human liver disease. Mice treated with norUDCA demonstrated reduced hepatocellular death by compensatory hepatocellular proliferation as determined by bromodeoxyuridine incorporation (3.8% control, 0.88% treated, P < 0.04). Ki-67 staining as a marker for hepatocellular senescence and death was also reduced (P < 0.02). Reduced apoptotic signaling was associated with norUDCA, including reduced cleavage of caspases-3, -7, and -8 (all P < 0.05). We determined that norUDCA was associated with a >70% reduction in intrahepatic mutant Z protein (P < 0.01). A 32% increase in hepatic autophagy associated with norUDCA was the likely mechanism. norUDCA administration is associated with increased autophagy, reduced A1AT protein accumulation, and reduced liver injury in a model of A1AT deficiency.

Alpha-1 Antitrypsin Deficiency Today: New Insights in the Immunological Pathways.

More than 50 years ago, the observation that absence of the α1 band from protein electrophoresis is associated with severe emphysema established the link between α1-antitrypsin deficiency (AATD) and lung damage. From this discovery, the classic paradigm of protease/antiprotease imbalance was derived, linking lung destruction in patients with AATD to the unopposed effect of proteases. By extension, this paradigm was also applied to patients with 'common' chronic obstructive pulmonary disease, in whom large increases in smoke-induced proteases could overwhelm the antiprotease capability of AAT. However, it has become increasingly evident that AAT has important anti-inflammatory and immunoregulatory activities which, beside its antiprotease function, may be critically involved in lung destruction. From this perspective, we will consider recent evidence, based on epidemiological, clinical and immunopathological studies, suggesting that it is time to move on from the original protease/antiprotease paradigm toward a more complex view of the condition, which embraces its immunomodulating functions. Of importance, the potent immunoregulatory, tolerogenic role of AAT may support its therapeutic use in a number of diseases other than AATD, particularly in immune-related disorders.

Immune activation in α1-antitrypsin-deficiency emphysema. Beyond the protease-antiprotease paradigm.

RATIONALE: α1-Antitrypsin (AAT) is a potent protease inhibitor, deficiency of which is associated with the presence of emphysema. An imbalance of elastase and antielastase, along with innate inflammation in the lung, is believed to cause lung destruction in α1-antitrypsin deficiency (AATD). It is now apparent that AAT has important immune-regulatory roles that would be lost in AATD, yet adaptive immune responses in the lung have not been investigated in patients with AATD. OBJECTIVES: To assess the adaptive immune response in severe AATD emphysema and compare it with that present in "usual" chronic obstructive pulmonary disease (COPD). METHODS: The immune inflammatory response in explanted lungs from 10 subjects with AATD was characterized and quantified, and the results were compared with those of 26 subjects with usual COPD and those of 17 smoking and 11 nonsmoking control subjects with normal lung function. MEASUREMENTS AND MAIN RESULTS: Lymphoid follicles (LFs) in AATD and usual COPD were markedly increased when compared with control groups. Molecular analysis of B lymphocytes in LFs showed predominantly mono/oligoclonality. LF number correlated negatively with FEV1/FVC. B lymphocytes and CD4(+) and CD8(+) T lymphocytes were significantly increased in AATD and usual COPD when compared with control groups. IL-32, an important cytokine in induction of autoimmunity, was markedly up-regulated in AATD and usual COPD. CONCLUSIONS: An important adaptive immune inflammation, comprising B, CD4(+), and CD8(+) lymphocytes, and LFs, is a prominent feature in AATD. These results change the paradigm of the mechanism of AATD-induced emphysema from a pure elastase-antielastase imbalance to a much more complex one involving the adaptive immune system, similarly to what occurs in usual COPD.

The role of bronchial epithelial cells in the pathogenesis of COPD in Z-alpha-1 antitrypsin deficiency.

BACKGROUND: Alpha-1 antitrypsin is the main inhibitor of neutrophil elastase in the lung. Although it is principally synthesized by hepatocytes, alpha-1 antitrypsin is also secreted by bronchial epithelial cells. Gene mutations can lead to alpha-1 antitrypsin deficiency, with the Z variant being the most clinically relevant due to its propensity to polymerize. The ability of bronchial epithelial cells to produce Z-variant protein and its polymers is unknown. METHODS: Experiments using a conformation-specific antibody were carried out on M- and Z-variant-transfected 16HBE cells and on bronchial biopsies and ex vivo bronchial epithelial cells from Z and M homozygous patients. In addition, the effect of an inflammatory stimulus on Z-variant polymer formation, elicited by Oncostatin M, was investigated. Comparisons of groups were performed using t-test or ANOVA. Non-normally distributed data were assessed by Mann-Whitney U test or the Kruskal-Wallis test, where appropriate. A P value of < 0.05 was considered to be significant. RESULTS: Alpha-1 antitrypsin polymers were found at a higher concentration in the culture medium of ex vivo bronchial epithelial cells from Z-variant homozygotes, compared with M-variant homozygotes (P < 0.01), and detected in the bronchial epithelial cells and submucosa of patient biopsies. Oncostatin M significantly increased the expression of alpha-1 antitrypsin mRNA and protein (P < 0.05), and the presence of Z-variant polymers in ex vivo cells (P < 0.01). CONCLUSIONS: Polymers of Z-alpha-1 antitrypsin form in bronchial epithelial cells, suggesting that these cells may be involved in the pathogenesis of lung emphysema and in bronchial epithelial cell dysfunction.

Serum concentration of alpha-1 antitrypsin is significantly higher in colorectal cancer patients than in healthy controls.

BACKGROUND: The association between alpha-1 antitrypsin (AAT) deficiency and colorectal cancer (CRC) is currently controversial. The present study compares AAT serum concentrations and gene frequencies between a group of CRC patients and a control group of healthy unrelated people (HUP). METHODS: 267 CRC subjects (63% males, 72 ± 10 years old) were enlisted from a Hospital Clinic setting in Asturias, Spain. The HUP group comprised 327 subjects (67% males, mean age 70 ± 7.5 years old) from the same geographical region. Outcome measures were AAT serum concentrations measured by nephelometry, and AAT phenotyping characterization by isoelectric focusing. RESULTS: Significantly higher serum concentrations were found among CRC (208 ± 60) than in HUP individuals (144 ± 20.5) (p = 0.0001). No differences were found in the phenotypic distribution of the Pi*S and Pi*Z allelic frequencies (p = 0.639), although the frequency of Pi*Z was higher in CRC (21%) than in HUP subjects (15%). CONCLUSIONS: The only statistically significant finding in this study was the markedly higher AAT serum concentrations found in CRC subjects compared with HUP controls, irrespective of whether their Pi* phenotype was normal (Pi*MM) or deficient (Pi*MS, Pi*MZ and Pi*SZ). Although there was a trend towards the more deficient Pi* phenotype the more advanced the tumor, the results were inconclusive due to the small sample size. Consequently, more powerful studies are needed to reach firmer conclusions on this matter.

Targeting intracellular degradation pathways for treatment of liver disease caused by α1-antitrypsin deficiency.

The classic form of α1-antitrypsin deficiency (ATD) is a well-known genetic cause of severe liver disease in childhood. A point mutation alters the folding of a hepatic secretory glycoprotein such that the protein is prone to misfolding and polymerization. Liver injury, characterized predominantly by fibrosis/cirrhosis and carcinogenesis, is caused by the proteotoxic effect of polymerized mutant α1-antitrypsin Z (ATZ), which accumulates in the endoplasmic reticulum (ER) of hepatocytes. Several intracellular pathways have been shown to be responsible for disposal of ATZ after it accumulates in the ER, but autophagy appears to be specialized for disposal of insoluble ATZ polymers. Recently, we have found that drugs that enhance the activity of the autophagic pathway reduce the cellular load of mutant ATZ and reverse hepatic fibrosis in a mouse model of ATD. Because several of these autophagy enhancers have been used safely in humans for other reasons, we have been able to initiate a clinical trial of one of these drugs, carbamazepine, to determine its efficacy in severe liver disease due to ATD. In this review, we discuss the autophagy enhancer drugs as a new therapeutic strategy that targets cell biological mechanisms integral to the pathogenesis of liver disease due to ATD.

Alpha-1 antitrypsin augmentation therapy.

The therapy of alpha-1 antitrypsin deficiency (AATD) is an example of a medical triumph over a common hereditary disease. Based on the understanding of the pathogens of the disease as a deficiency in liver production of alpha-1 antitrypsin (AAT) resulting from inherited genetic variation in both parental AAT genes, the knowledge that A1AT functions primarily to inhibit neutrophil elastase (NE), and the observation that NE instilled into the lung of experimental animals resulted in emphysema, the concept evolved that the pulmonary manifestations of the disease could be halted by intermittent intravenous infusions of AAT purified from pooled human plasma. Following preliminary clinical studies in the academic community, and then pharmaceutical company development of large scale purification of human AAT, the FDA approved the use of weekly AAT augmentation therapy for AATD following a clinical trial which demonstrated that weekly infusions would raise to normal plasma and lung epithelial fluid levels of AAT in AAT-deficient individuals. The therapy is now used worldwide to treat AATD, the only pulmonary genetic disease with effective therapy for all affected individuals.

Neutrophil elastase-mediated lung disease.

Elastases of both the neutrophil and macrophage have been implicated in lung disease initiation and progression. Although it is unlikely that these proteases evolved for the purpose of injuring lung tissue, the elastin-rich connective tissue framework of the lungs appears to be particularly susceptible to the action of elastolytic proteases. Assuming that neutrophil elastase most likely plays a role in the migration of neutrophils toward a site of inflammation and degradation of proteins from invading organisms or other products of the inflammatory response, it is the role of inhibitors of this protease to protect normal tissues from its effects. In alpha-1 antitrypsin deficiency we find an experiment of nature that disrupts this protease-anti-protease balance, resulting in an increased risk of destructive lung disease.

Genetic modifiers of liver injury in hereditary liver disease.

The genetic background of patients with liver diseases modulates hepatic injury, with some individuals being predisposed to better defenses and regenerative capacity. In this review, we focus our description of this phenomenon on inherited disorders affecting the liver, with a particular emphasis on Wilson disease (WD), genetic hemochromatosis, and α-1 anti-trypsin disease (A1-AT). Wide variations in the clinical phenotype of WD may in part be related to the mutations of the ATP7B genotype, though modifier genes and environmental factors also likely play an important role. There is also a significant variability in the expression of iron overload in patients with genetic hemochromatosis that are homozygous for the C282Y mutation. Homozygosity for the A1-ATZ mutation is generally required for the development of liver disease in A1-AT although there is increasing evidence for modifier effects from a heterozygous genotype in other liver diseases.

Matrix metalloproteinase-9 predicts pulmonary status declines in α1-antitrypsin deficiency.

BACKGROUND: Matrix metalloproteinase-9 (MMP-9) may be important in the progression of emphysema, but there have been few longitudinal clinical studies of MMP-9 including pulmonary status and COPD exacerbation outcomes. METHODS: We utilized data from the placebo arm (n=126) of a clinical trial of patients with alpha1-antitrypsin deficiency (AATD) and emphysema to examine the links between plasma MMP-9 levels, pulmonary status, and COPD exacerbations over a one year observation period. Pulmonary function, computed tomography lung density, incremental shuttle walk test (ISWT), and COPD exacerbations were assessed at regular intervals over 12 months. Prospective analyses used generalized estimating equations to incorporate repeated longitudinal measurements of MMP-9 and all endpoints, controlling for age, gender, race-ethnicity, leukocyte count, and tobacco history. A secondary analysis also incorporated highly-sensitive C-reactive protein levels in predictive models. RESULTS: At baseline, higher plasma MMP-9 levels were cross-sectionally associated with lower FEV1 (p=0.03), FVC (p<0.001), carbon monoxide transfer factor (p=0.03), resting oxygen saturation (p=0.02), and ISWT distance walked (p=0.02) but were not associated with radiographic lung density or total lung capacity (TLC). In longitudinal analyses, MMP-9 predicted a further decline in transfer factor (p=0.04) and oxygen saturation (p<0.001). MMP-9 also predicted worsening lung density (p=0.003), increasing TLC (p=0.02), and more frequent COPD exacerbations over follow-up (p=0.003). Controlling additionally for hs-CRP levels did not substantively change the longitudinal associations between MMP-9 and these outcomes. CONCLUSIONS: Increased plasma MMP-9 levels generally predicted pulmonary status declines, including worsening transfer factor and lung density as well as greater COPD exacerbations in AATD-associated emphysema.

Alpha-1-antitrypsin is produced by human neutrophil granulocytes and their precursors and liberated during granule exocytosis.

Alpha-1-antitrypsin (A1AT) is an important inhibitor of neutrophil proteases including elastase, cathepsin G, and proteinase 3. Transcription profiling data suggest that A1AT is expressed by human neutrophil granulocytes during all developmental stages. A1AT has hitherto only been found associated with azurophile granules in neutrophils indicative of A1AT expression being restricted to the promyelocyte stage. We examined the localization and production of A1AT in healthy donor neutrophils and found A1AT to be a constituent of all granule subtypes and to be released from neutrophils following stimulation. A1AT is produced at all stages of myeloid maturation in the bone marrow. The production increases as neutrophils enter circulation and increases further upon migration to tissues as observed in skin windows and when blood neutrophils are incubated with granulocyte colony-stimulating factor. Neutrophils from patients with A1AT-deficiency carrying the (PI)ZZ mutation in the A1AT gene appeared structurally and functionally normal, but A1AT produced in leukocytes of these patients lacked the ability to bind proteases efficiently. We conclude that A1AT generation and release from neutrophils add significantly to the antiprotease levels in tissues during inflammation. Impaired binding of neutrophil A1AT to serine proteases in patients with (PI)ZZ mutations may enhance their susceptibility to the development of emphysema.

Engineering synthetic breath biomarkers for respiratory disease.

Human breath contains many volatile metabolites. However, few breath tests are currently used in the clinic to monitor disease due to bottlenecks in biomarker identification. Here we engineered breath biomarkers for respiratory disease by local delivery of protease-sensing nanoparticles to the lungs. The nanosensors shed volatile reporters upon cleavage by neutrophil elastase, an inflammation-associated protease with elevated activity in lung diseases such as bacterial infection and alpha-1 antitrypsin deficiency. After intrapulmonary delivery into mouse models with acute lung inflammation, the volatile reporters are released and expelled in breath at levels detectable by mass spectrometry. These breath signals can identify diseased mice with high sensitivity as early as 10 min after nanosensor administration. Using these nanosensors, we performed serial breath tests to monitor dynamic changes in neutrophil elastase activity during lung infection and to assess the efficacy of a protease inhibitor therapy targeting neutrophil elastase for the treatment of alpha-1 antitrypsin deficiency.

The liver in 30-year-old individuals with alpha(1)-antitrypsin deficiency.

OBJECTIVE. Severe (PiZZ) alpha(1)-antitrypsin (AAT) deficiency is a risk factor for liver disease, i.e. juvenile cirrhosis in infancy, and cirrhosis and hepatoma in adulthood. Little is known about the risk of liver disease in individuals with moderate (PiSZ) AAT deficiency. To investigate the natural course of AAT deficiency, a cohort of PiZZ and PiSZ individuals identified by the Swedish National neonatal screening programme in 1972-74 is followed regularly. The aim of this study was to compare liver function in this cohort with healthy control subjects aged 30 years. MATERIAL AND METHODS. Blood samples were obtained from 89 PiZZ, 40 PiSZ, and 84 control subjects (PiMM), and plasma levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma-glutamyl (GT) transpeptidase were analysed. RESULTS. The mean values of all liver enzymes were within the normal range in all Pi subgroups. However, the mean AST was higher in the PiZZ and PiSZ subgroups than in the PiMM subgroup (p < 0.001), and the mean ALT was higher in the PiZZ individuals than in the controls (p < 0.05), while GT did not differ significantly among the Pi subgroups. The PiZZ women taking oral contraceptives had higher mean AST and ALT (p < 0.01) and GT (p < 0.05) than the control women taking oral contraceptives. CONCLUSIONS. At the age of 30 years, PiZZ and PiSZ individuals have normal plasma levels of the transaminases AST and ALT, although they are significantly higher than those in healthy control subjects. Use of oral contraceptives seems to influence liver enzymes in PiZZ women.