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McElvaney OF, Fraughen DD, McElvaney OJ, Carroll TP, McElvaney NG. Alpha-1 antitrypsin deficiency: current therapy and emerging targets. Expert Rev Respir Med 2023; 17:191-202. [PMID: 36896570 DOI: 10.1080/17476348.2023.2174973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
INTRODUCTION Alpha1 antitrypsin deficiency (AATD), a common hereditary disorder affecting mainly lungs, liver and skin has been the focus of some of the most exciting therapeutic approaches in medicine in the past 5 years. In this review, we discuss the therapies presently available for the different manifestations of AATD and new therapies in the pipeline. AREAS COVERED We review therapeutic options for the individual lung, liver and skin manifestations of AATD along with approaches which aim to treat all three. Along with this renewed interest in treating AATD come challenges. How is AAT best delivered to the lung? What is the desired level of AAT in the circulation and lungs which therapeutics should aim to provide? Will treating the liver disease increase the potential for lung disease? Are there treatments to target the underlying genetic defect with the potential to prevent all aspects of AATDrelated disease? EXPERT OPINION With a relatively small population able to participate in clinical studies, increased awareness and diagnosis of AATD is urgently needed. Better, more sensitive clinical parameters will assist in the generation of acceptable and robust evidence of therapeutic effect for current and emerging treatments.
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Affiliation(s)
- Oisín F McElvaney
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Medicine, Beaumont Hospital, Dublin, Ireland
| | - Daniel D Fraughen
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Medicine, Beaumont Hospital, Dublin, Ireland
| | - Oliver J McElvaney
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Medicine, Beaumont Hospital, Dublin, Ireland
| | - Tomás P Carroll
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Medicine, Beaumont Hospital, Dublin, Ireland.,Alpha-1 Foundation Ireland, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Noel G McElvaney
- Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Medicine, Beaumont Hospital, Dublin, Ireland
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Gonzalez A, Belmonte I, Nuñez A, Farago G, Barrecheguren M, Pons M, Orriols G, Gabriel-Medina P, Rodríguez-Frías F, Miravitlles M, Esquinas C. New variants of alpha-1-antitrypsin: structural simulations and clinical expression. Respir Res 2022; 23:339. [PMID: 36496391 PMCID: PMC9741788 DOI: 10.1186/s12931-022-02271-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Alpha-1 antitrypsin deficiency (AATD) is characterized by reduced serum levels of the AAT protein and predisposes to liver and lung disease. The characterization at structural level of novel pathogenic SERPINA1 mutants coding for circulating AAT could provide novel insights into the mechanisms of AAT misfolding. The present study aimed to provide a practical framework for the identification and analysis of new AAT mutations, combining structural simulations and clinical data. METHODS We analysed a total of five mutations (four not previously described) in a total of six subjects presenting moderate to severe AATD: Gly95Alafs*18, Val210Glu, Asn247Ser, Pi*S + Asp341His and Pi*S + Leu383Phe + Lys394Ile. Clinical data, genotyping and phenotyping assays, structural mapping, and conformational characterization through molecular dynamic (MD) simulations were developed and combined. RESULTS Newly discovered AAT missense variants were localized both on the interaction surface and the hydrophobic core of the protein. Distribution of mutations across the structure revealed Val210Glu at the solvent exposed s4C strand and close to the "Gate" region. Asn247Ser was located on the accessible surface, which is important for glycan attachment. On the other hand, Asp341His, Leu383Phe were mapped close to the "breach" and "shutter" regions. MD analysis revealed the reshaping of local interactions around the investigated substitutions that have varying effects on AAT conformational flexibility, hydrophobic packing, and electronic surface properties. The most severe structural changes were observed in the double- and triple-mutant (Pi*S + Asp341His and Pi*S + Leu383Phe + Lys394Ile) molecular models. The two carriers presented impaired lung function. CONCLUSIONS The results characterize five variants, four of them previously unknown, of the SERPINA1 gene, which define new alleles contributing to the deficiency of AAT. Rare variants might be more frequent than expected, and therefore, in discordant cases, standardized screening of the S and Z alleles needs complementation with gene sequencing and structural approaches. The utility of computational modelling for providing supporting evidence of the pathogenicity of rare single nucleotide variations is discussed.
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Affiliation(s)
- Angel Gonzalez
- grid.7080.f0000 0001 2296 0625Department of Computational Medicine, Statistic Unit, Medicine Faculty, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain
| | - Irene Belmonte
- grid.411083.f0000 0001 0675 8654Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Alexa Nuñez
- grid.411083.f0000 0001 0675 8654Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, P. Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Georgina Farago
- grid.411083.f0000 0001 0675 8654Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, P. Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Miriam Barrecheguren
- grid.411083.f0000 0001 0675 8654Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, P. Vall d’Hebron 119-129, 08035 Barcelona, Spain
| | - Mònica Pons
- grid.411083.f0000 0001 0675 8654Liver Unit, Department of Internal Medicine, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Gerard Orriols
- grid.411083.f0000 0001 0675 8654Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Pablo Gabriel-Medina
- grid.411083.f0000 0001 0675 8654Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Francisco Rodríguez-Frías
- grid.411083.f0000 0001 0675 8654Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain ,grid.7080.f0000 0001 2296 0625Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain ,grid.452371.60000 0004 5930 4607Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, (CIBEREHD), Barcelona, Spain ,grid.430994.30000 0004 1763 0287Clinical Biochemistry Research Group/Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Marc Miravitlles
- grid.411083.f0000 0001 0675 8654Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, P. Vall d’Hebron 119-129, 08035 Barcelona, Spain ,grid.512891.6Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), Barcelona, Spain
| | - Cristina Esquinas
- grid.411083.f0000 0001 0675 8654Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, P. Vall d’Hebron 119-129, 08035 Barcelona, Spain ,grid.5841.80000 0004 1937 0247Public Health, Mental, Maternal and Child Health Nursing Departament, Faculty of Medicine and Health Sciences, University of Barcelona, Barcelona, Spain
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3
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Stephenson SE, Wilson CL, Crothers K, Attia EF, Wongtrakool C, Petrache I, Schnapp LM. Impact of HIV infection on α 1-antitrypsin in the lung. Am J Physiol Lung Cell Mol Physiol 2017; 314:L583-L592. [PMID: 29351445 DOI: 10.1152/ajplung.00214.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Emphysema is one of the most common lung diseases in HIV+ individuals. The pathogenesis of HIV-associated emphysema remains unclear; however, radiographic distribution and earlier age of presentation of emphysema in the lungs of HIV+ patients are similar to deficiency of α1-antitrypsin (A1AT), a key elastase inhibitor in the lung. Reduced levels of circulating A1AT in HIV+ patients suggest a potential mechanism for emphysema development. In the present study we asked if A1AT levels and activity in the bronchoalveolar lavage fluid (BALF) differ in HIV+ and HIV- patients with and without emphysema. A1AT levels were measured by ELISA in plasma and BALF from a cohort of 21 HIV+ and 29 HIV- patients with or without emphysematous changes on chest CT scan. To analyze A1AT function, we measured elastase activity in the BALF and assessed oxidation and polymerization of A1AT by Western blotting. Total A1AT was increased in the BALF, but not in the plasma, of HIV+ compared with HIV- patients, regardless of the presence or absence of emphysema. However, antielastase activity was decreased in BALF from HIV+ patients, suggesting impaired A1AT function. Higher levels of the oxidized form of A1AT were detected in BALF from HIV+ than HIV- patients, which may account for the decreased antielastase activity. These findings suggest that, in the lungs of HIV+ patients, posttranslational modifications of A1AT produce a "functional deficiency" of this critical elastase inhibitor, which may contribute to emphysema development.
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Affiliation(s)
- Sarah E Stephenson
- Pulmonary, Critical Care, Allergy, and Sleep Medicine, Medical University of South Carolina , Charleston, South Carolina
| | - Carole L Wilson
- Pulmonary, Critical Care, Allergy, and Sleep Medicine, Medical University of South Carolina , Charleston, South Carolina
| | - Kristina Crothers
- Pulmonary and Critical Care Medicine, University of Washington , Seattle, Washington
| | - Engi F Attia
- Pulmonary and Critical Care Medicine, University of Washington , Seattle, Washington
| | - Cherry Wongtrakool
- Pulmonary Section, Department of Veterans Affairs, Atlanta Veterans Affairs Medical Center, Decatur, Georgia.,Division of Pulmonary, Critical Care, Allergy, and Sleep Medicine, Department of Medicine, Emory University , Atlanta, Georgia
| | - Irina Petrache
- Pulmonary, Critical Care, and Sleep Medicine, National Jewish Health, University of Colorado , Denver, Colorado
| | - Lynn M Schnapp
- Pulmonary, Critical Care, Allergy, and Sleep Medicine, Medical University of South Carolina , Charleston, South Carolina
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4
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Loring HS, Flotte TR. Current status of gene therapy for α-1 antitrypsin deficiency. Expert Opin Biol Ther 2014; 15:329-36. [DOI: 10.1517/14712598.2015.978854] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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5
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Holme J, Stockley JA, Stockley RA. Age related development of respiratory abnormalities in non-index α-1 antitrypsin deficient studies. Respir Med 2013; 107:387-93. [DOI: 10.1016/j.rmed.2012.12.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/16/2012] [Accepted: 12/06/2012] [Indexed: 12/29/2022]
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6
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Brylinski M, Konieczny L, Kononowicz A, Roterman I. Conservative secondary structure motifs already present in early-stage folding (in silico) as found in serpines family. J Theor Biol 2007; 251:275-85. [PMID: 18177901 DOI: 10.1016/j.jtbi.2007.10.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 10/31/2007] [Accepted: 10/31/2007] [Indexed: 11/27/2022]
Abstract
The well-known procedure implemented in ClustalW oriented on the sequence comparison was applied to structure comparison. The consensus sequence as well as consensus structure has been defined for proteins belonging to serpine family. The structure of early stage intermediate was the object for similarity search. The high values of W(sequence) appeared to be accordant with high values of W(structure) making possible structure comparison using common criteria for sequence and structure comparison. Since the early stage structural form has been created according to limited conformational sub-space which does not include the beta-structure (this structure is mediated by C7eq structural form), is particularly important to see, that the C7eq structural form may be treated as the seed for beta-structure present in the final native structure of protein. The applicability of ClustalW procedure to structure comparison makes these two comparisons unified.
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Affiliation(s)
- Michal Brylinski
- Department of Bioinformatics and Telemedicine, Collegium Medicum-Jagiellonian University, Kopernika 17, 31501 Cracow, Poland
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Flaugh SL, Mills IA, King J. Glutamine deamidation destabilizes human gammaD-crystallin and lowers the kinetic barrier to unfolding. J Biol Chem 2006; 281:30782-93. [PMID: 16891314 DOI: 10.1074/jbc.m603882200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human eye lens transparency requires life long stability and solubility of the crystallin proteins. Aged crystallins have high levels of covalent damage, including glutamine deamidation. Human gammaD-crystallin (HgammaD-Crys) is a two-domain beta-sheet protein of the lens nucleus. The two domains interact through interdomain side chain contacts, including Gln-54 and Gln-143, which are critical for stability and folding of the N-terminal domain of HgammaD-Crys. To test the effects of interface deamidation on stability and folding, single and double glutamine to glutamate substitutions were constructed. Equilibrium unfolding/refolding experiments of the proteins were performed in guanidine hydrochloride at pH 7.0, 37 degrees C, or urea at pH 3.0, 20 degrees C. Compared with wild type, the deamidation mutants were destabilized at pH 7.0. The proteins populated a partially unfolded intermediate that likely had a structured C-terminal domain and unstructured N-terminal domain. However, at pH 3.0, equilibrium unfolding transitions of wild type and the deamidation mutants were indistinguishable. In contrast, the double alanine mutant Q54A/Q143A was destabilized at both pH 7.0 and 3.0. Thermal stabilities of the deamidation mutants were also reduced at pH 7.0. Similarly, the deamidation mutants lowered the kinetic barrier to unfolding of the N-terminal domain. These data indicate that interface deamidation decreases the thermodynamic stability of HgammaD-Crys and lowers the kinetic barrier to unfolding due to introduction of a negative charge into the domain interface. Such effects may be significant for cataract formation by inducing protein aggregation or insolubility.
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Affiliation(s)
- Shannon L Flaugh
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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8
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Cicardi M, Zingale L, Zanichelli A, Pappalardo E, Cicardi B. C1 inhibitor: molecular and clinical aspects. ACTA ACUST UNITED AC 2005; 27:286-98. [PMID: 16267649 DOI: 10.1007/s00281-005-0001-4] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Accepted: 06/21/2005] [Indexed: 01/23/2023]
Abstract
C1 inhibitor (C1-INH) is a serine protease inhibitor (serpins) that inactivates several different proteases in the complement, contact, coagulation, and fibrinolytic systems. By its C-terminal part (serpin domain), characterized by three beta-sheets and an exposed mobile reactive loop, C1-INH binds, and blocks the activity of its target proteases. The N-terminal end (nonserpin domain) confers to C1-INH the capacity to bind lipopolysaccharides and E-selectin. Owing to this moiety, C1-INH intervenes in regulation of the inflammatory reaction. The heterozygous deficiency of C1-INH results in hereditary angioedema (HAE). The clinical picture of HAE is characterized by bouts of local increase in vascular permeability. Depending on the affected site, patients suffer from disfiguring subcutaneous edema, abdominal pain, vomiting and/or diarrhoea for edema of the gastrointestinal mucosa, dysphagia, and dysphonia up to asphyxia for edema of the pharynx and larynx. Apart from its genetic deficiency, there are several pathological conditions such as ischemia-reperfusion, septic shock, capillary leak syndrome, and pancreatitis, in which C1-INH has been reported to either play a pathogenic role or be a potential therapeutic tool. These potential applications were identified long ago, but controlled studies have not been performed to confirm pilot experiences. Recombinant C1-INH, produced in transgenic animals, has recently been produced for treatment of HAE, and clinical trials are in progress. We can expect that the introduction of this new product, along with the existing plasma derivative, will renew interest in exploiting C1-INH as a therapeutic agent.
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Affiliation(s)
- Marco Cicardi
- Department of Internal Medicine, San Giuseppe Hospital, University of Milan, Milan, Italy.
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9
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Fetz K, Ruaux CG, Steiner JM, Suchodolski JS, Williams DA. Purification and partial characterization of feline α1-proteinase inhibitor (fα1-PI) and the development and validation of a radioimmunoassay for the measurement of fα1-PI in serum. Biochimie 2004; 86:67-75. [PMID: 14987802 DOI: 10.1016/j.biochi.2003.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2003] [Accepted: 10/02/2003] [Indexed: 12/21/2022]
Abstract
Alpha(1)-proteinase inhibitor (alpha(1)-PI) of the domestic cat (Felis catus) was purified from serum and a radioimmunoassay (RIA) for the measurement of feline alpha(1)-PI concentration in serum was developed and validated. Feline alpha(1)-PI (falpha(1)-PI) was isolated using ammonium sulfate precipitation, anion-exchange, size-exclusion, ceramic hydroxyapatite, and hydrophobic interaction chromatography. The molecular weight of falpha(1)-PI was estimated at 57,000 and the relative molecular mass (M(r)) was determined to be approximately 54.5 kDa. Isoelectric focusing revealed four bands with isoelectric points (pI) between 4.3 and 4.5. The N-terminal amino acid sequence of the first 19 residues was Glu-Gly-Leu-Gln-Gly-Ala-Ala-Val-Gln-Glu-Thr-Val-Ala-Ser-Gln-His-Asp-Gln-Glu. Antiserum against feline alpha(1)-PI was raised in rabbits. Tracer was produced by iodination ((125)I) of feline alpha(1)-PI using the chloramine T method. A radioimmunoassay was established and validated by determination of sensitivity, dilutional parallelism, spiking recovery, intra-assay variability, and inter-assay variability. A control range for serum feline alpha(1)-PI concentration was established from 50 healthy cats using the central 95th percentile. The sensitivity of the assay was 0.042 mg/ml. Observed to expected ratios for serial dilutions ranged from 105% to 141.18% for four different serum samples at dilutions of 1 in 35,000, 1 in 70,000, 1 in 140,000 and 1 in 280,000. Observed to expected ratios for spiking recovery ranged from 88.14% to 152.17% for four different serum samples and five different spiking concentrations. Coefficients of variation for four different serum samples were 4.57%, 6.45%, 8.52%, and 4.27% for intra-assay variability and 6.88%, 9.57%, 7.44%, and 9.94% for inter-assay variability. The reference range was established as 0.25-0.6 mg/ml. In summary, feline alpha(1)-PI was successfully purified from serum using a rapid and efficient method. The radioimmunoassay described here is sensitive, linear, accurate, precise, and reproducible and will facilitate further studies of the physiological or potential pathological role of alpha(1)-PI in cats.
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Affiliation(s)
- Kathrin Fetz
- Gastrointestinal Laboratory, Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4474, USA.
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10
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Janciauskiene S, Dominaitiene R, Sternby NH, Piitulainen E, Eriksson S. Detection of circulating and endothelial cell polymers of Z and wild type alpha 1-antitrypsin by a monoclonal antibody. J Biol Chem 2002; 277:26540-6. [PMID: 12023970 DOI: 10.1074/jbc.m203832200] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Globular inclusions of abnormal alpha1-antitrypsin (AAT) in the endoplasmic reticulum of hepatocytes are a characteristic feature of AAT deficiency of the PiZZ phenotype. Monoclonal antibodies, which contain constant specificity and affinity, are often used for the identification of Z-mutation carriers. A mouse monoclonal antibody (ATZ11) raised against PiZZ hepatocytic AAT was successfully used in enzyme-linked immunosorbent assays (ELISA) and in identification of Z-related AAT globular inclusions by immunohistochemical techniques. Using electrophoresis, Western blotting, and ELISA procedures, we have shown in the present study that this monoclonal antibody specifically detects a conformation-dependent neoepitope on both polymerized and elastase-complexed molecular forms of AAT. The antibody has no apparent affinity for native, latent, or cleaved forms of AAT. The antibody ATZ11 illustrates the structural resemblance between the polymerized form of AAT and its complex with elastase and provides evidence that Z-homozygotes beyond the native form may have at least one more circulating molecular form of AAT, i.e. its polymerized form. In addition, staining of endothelial cells with ATZ11 antibody in both M- and Z-AAT individuals shows that AAT attached to endothelial cells is in a polymerized form. The antibody can be a powerful tool for the study of the molecular profile of AAT, not only in Z-deficiency cases but also in other (patho)physiological conditions.
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Affiliation(s)
- Sabina Janciauskiene
- Department of Internal Medicine, University Hospital, Malmö, 20502 Malmö, Sweden.
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11
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Tran ST, Shrake A. The folding of alpha-1-proteinase inhibitor: kinetic vs equilibrium control. Arch Biochem Biophys 2001; 385:322-31. [PMID: 11368013 DOI: 10.1006/abbi.2000.2186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous folding studies of alpha-1-proteinase inhibitor (alpha1-PI), which regulates the activity of the serine protease human neutrophil elastase, show an intermediate state at approximately 1.5 M guanidine-HCl (Gu). For the normal form of alpha1-PI, we demonstrate the reversible formation of the same stable distribution of monomeric and polymeric intermediates after approximately 1 h in 1.5 M Gu at approximately 23 degrees C from fully folded or fully unfolded alpha1-PI at similar final total concentrations and show that the stable distribution of monomeric and polymeric intermediates conforms with the law of mass action. We attribute these observations to an apparent equilibrium among intermediates. Our CD data are compatible with the intermediates having slightly relaxed structures relative to that of fully folded alpha1-PI and, thus, with the polymeric intermediates having a loop-sheet structure. Furthermore, we observe that the rates of folding (fast and slow terms) from the intermediate state are the same as those from the fully unfolded state, thereby supporting the contention that this intermediate state is on the folding pathway. We attribute the tendency of the Z mutant protein to polymerize/aggregate to an increased rate of the monomeric intermediate to form the apparent equilibrium distribution of intermediate species relative to its rate of folding to give intact alpha1-PI.
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Affiliation(s)
- S T Tran
- Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, Maryland 20892, USA
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Wolff RK. Safety of inhaled proteins for therapeutic use. JOURNAL OF AEROSOL MEDICINE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY FOR AEROSOLS IN MEDICINE 1999; 11:197-219. [PMID: 10346664 DOI: 10.1089/jam.1998.11.197] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The use of the inhalation route for delivery of inhaled proteins has received increasing attention recently. The purpose of this article is to review the available information related to the safety aspects of inhaled proteins. The review focuses primarily on possible toxicity to the respiratory tract, because usually one is either considering an agent to treat the lung or an agent for which the systemic toxicity has been investigated following subcutaneous (s.c.) administration in its clinical use as a therapeutic agent. Some background is provided on mechanisms of absorption and reasons why inhalation delivery is considered for many proteins. Available data are summarized from clinical trials of proteins and protein-like biomolecules, generally showing minimal, if any, adverse respiratory effects. The results of the animal toxicology studies that have been published are presented. In general, the observed lung toxicity has been relatively low, and it has been difficult to interpret in cases where the animal protein differs considerably from the human protein. Discussion is presented on the possibility of adverse immune reactions, suggesting that this is not likely to be any greater issue than it is for subcutaneously injected materials. Although the safety information is relatively sparse at present, the available data suggest that the inhalation route can be an attractive route to consider for many therapeutic proteins.
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Affiliation(s)
- R K Wolff
- Toxicology Research Labs, Lilly Research Laboratory, Greenfield, IN 46140, USA.
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13
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Graziadei IW, Joseph JJ, Wiesner RH, Therneau TM, Batts KP, Porayko MK. Increased risk of chronic liver failure in adults with heterozygous alpha1-antitrypsin deficiency. Hepatology 1998; 28:1058-63. [PMID: 9755243 DOI: 10.1002/hep.510280421] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Controversy exists whether patients who are genetically heterozygous for 1-antitrypsin deficiency (1ATD), carrying a single PI*Z allele, are at increased risk of developing chronic liver disease. In these investigations, we determined the prevalence of heterozygous 1AT phenotypes (PI MZ, PI SZ) in a well-characterized cohort of patients presenting with chronic liver failure before orthotopic liver transplantation (OLT). We analyzed data collected from all adult patients (n = 641) who underwent OLT at our tertiary referral center between March 1985 and December 1996. Study patients entered a prospective protocol designed to test for all known etiologies of liver disease. Complete testing including 1AT phenotyping was successfully performed in 599 adults. We compared the overall number of heterozygous PI*Z carriers in our OLT cohort with established prevalence figures for general and regional American populations, and examined their distribution among various liver disease subgroups. Fifty-one patients were found to be heterozygous carriers of a single PI*Z allele for 1AT. The predominant phenotype in our transplantation cohort was PI MZ, identified in 49 patients (8.2%), which is a significantly higher prevalence than that reported from previous American population studies (2%-4%). Additionally, a significantly greater number of PI MZ carriers existed in patients with cryptogenic cirrhosis compared with other liver disease categories (26.9%; P < .001). These data suggest that individuals carrying a single PI*Z allele for 1AT may be at increased risk of developing cirrhosis and liver failure, even in the absence of an identifiable coexisting liver disease.
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Affiliation(s)
- I W Graziadei
- Liver Transplant Unit, Mayo Clinic and Mayo Foundation, Rochester, MN 55905, USA
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Gerbod MC, Janciauskiene S, Jeppsson JO, Eriksson S. The in vitro effect of lithocholic acid on the polymerization properties of PiZ alpha-1-antitrypsin. Arch Biochem Biophys 1998; 351:167-74. [PMID: 9514645 DOI: 10.1006/abbi.1997.0541] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe here an in vitro effect of lithocholic acid (LA), a secondary, hydrophobic bile acid, on the rate of polymerization of mutant, Z and wild-type, M alpha-1-antitrypsin (AAT). Using thioflavine T fluorescence and turbidity assays we demonstrated that the rate of aggregation for the Z AAT in the presence of LA at a molar ratio of 1:5 AAT to LA, in Tris-buffered saline, pH 7.4, is at least twice that of the Z protein alone or the M variant with and without LA. Also, Z AAT incubated for 48 h at room temperature had more than 50% diminished antielastase activity, while M AAT had only a 25% reduction in activity. Analysis of the AAT and AAT-LA samples after cleavage with pancreatic elastase by SDS-PAGE 10% gels showed that interaction between Z or M AAT and LA abolishes their ability to form SDS stable complexes with an enzyme and both of these forms of AAT showed elastase substrate behavior. Furthermore, Z as well as M AAT incubated with LA at 41 degrees C and cleaved with elastase showed only 80 to 60% increased thermal stability compared to 100% stabilization for the cleaved AAT alone in the absence of LA. These observations suggest that a rearrangement of the AAT molecule as a result of interactions with LA increases aggregation of AAT and diminishes its inhibitory activity.
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Affiliation(s)
- M C Gerbod
- Department of Medicine, Lund University, Malmö, S-20502, Sweden
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Cribbs DH, Pike CJ, Weinstein SL, Velazquez P, Cotman CW. All-D-enantiomers of beta-amyloid exhibit similar biological properties to all-L-beta-amyloids. J Biol Chem 1997; 272:7431-6. [PMID: 9054444 DOI: 10.1074/jbc.272.11.7431] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The amyloidogenic peptide beta-amyloid has previously been shown to bind to neurons in the form of fibrillar clusters on the cell surface, which induces neurodegeneration and activates a program of cell death characteristic of apoptosis. To further investigate the mechanism of Abeta neurotoxicity, we synthesized the all-D- and all-L-stereoisomers of the neurotoxic truncated form of Abeta (Abeta25-35) and the full-length peptide (Abeta1-42) and compared their physical and biological properties. We report that the purified peptides exhibit nearly identical structural and assembly characteristics as assessed by high performance liquid chromatography, electron microscopy, circular dichroism, and sedimentation analysis. In addition, both enantiomers induce similar levels of toxicity in cultured hippocampal neurons. These data suggest that the neurotoxic actions of Abeta result not from stereoisomer-specific ligand-receptor interactions but rather from Abeta cellular interactions in which fibril features of the amyloidogenic peptide are a critical feature. The promiscuous nature of these beta-sheet-containing fibrils suggests that the accumulation of amyloidogenic peptides in vivo as extracellular deposits represents a site of bioactive peptides with the ability to provide inappropriate signals to cells leading to cellular degeneration and disease.
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Affiliation(s)
- D H Cribbs
- Institute for Brain Aging and Dementia, Departments of Psychobiology, University of California Irvine, Irvine, California 92697-4540, USA.
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Abstract
Recent publications strongly support the hypothesis that conformational changes in amyloidogenic proteins lead to amyloid fibril formation and cause disease. Biophysical studies on several amyloidogenic proteins provide insights into the conformational changes required for fibrilogenesis. In addition, newly available moderate to high resolution structural studies are bringing us closer to understanding the structure of amyloid.
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Affiliation(s)
- J W Kelly
- Department of Chemistry, Texas A&M University, College Station 77843-3255, USA.
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