1
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Kamuda K, Ronzoni R, Majumdar A, Guan FHX, Irving JA, Lomas DA. A novel pathological mutant reveals the role of torsional flexibility in the serpin breach in adoption of an aggregation-prone intermediate. FEBS J 2024; 291:2937-2954. [PMID: 38523412 DOI: 10.1111/febs.17121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/17/2024] [Accepted: 03/07/2024] [Indexed: 03/26/2024]
Abstract
Mutants of alpha-1-antitrypsin cause the protein to self-associate and form ordered aggregates ('polymers') that are retained within hepatocytes, resulting in a predisposition to the development of liver disease. The associated reduction in secretion, and for some mutants, impairment of function, leads to a failure to protect lung tissue against proteases released during the inflammatory response and an increased risk of emphysema. We report here a novel deficiency mutation (Gly192Cys), that we name the Sydney variant, identified in a patient in heterozygosity with the Z allele (Glu342Lys). Cellular analysis revealed that the novel variant was mostly retained as insoluble polymers within the endoplasmic reticulum. The basis for this behaviour was investigated using biophysical and structural techniques. The variant showed a 40% reduction in inhibitory activity and a reduced stability as assessed by thermal unfolding experiments. Polymerisation involves adoption of an aggregation-prone intermediate and paradoxically the energy barrier for transition to this state was increased by 16% for the Gly192Cys variant with respect to the wild-type protein. However, with activation to the intermediate state, polymerisation occurred at a 3.8-fold faster rate overall. X-ray crystallography provided two crystal structures of the Gly192Cys variant, revealing perturbation within the 'breach' region with Cys192 in two different orientations: in one structure it faces towards the hydrophobic core while in the second it is solvent-exposed. This orientational heterogeneity was confirmed by PEGylation. These data show the critical role of the torsional freedom imparted by Gly192 in inhibitory activity and stability against polymerisation.
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Affiliation(s)
- Kamila Kamuda
- Division of Medicine, UCL Respiratory, Rayne Institute, University College London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University College London, UK
| | - Riccardo Ronzoni
- Division of Medicine, UCL Respiratory, Rayne Institute, University College London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University College London, UK
| | - Avik Majumdar
- AW Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, Australia
- Victorian Liver Transplant Unit, Austin Health, Melbourne, Australia
- The University of Melbourne, Melbourne, Australia
| | - Fiona H X Guan
- AW Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, Australia
| | - James A Irving
- Division of Medicine, UCL Respiratory, Rayne Institute, University College London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University College London, UK
| | - David A Lomas
- Division of Medicine, UCL Respiratory, Rayne Institute, University College London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University College London, UK
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2
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Vickers S, Irving J, Lomas DA, Thalassinos K. Native and Ion Mobility Mass Spectrometry Characterization of Alpha 1 Antitrypsin Variants and Oligomers. Methods Mol Biol 2024; 2750:41-55. [PMID: 38108966 DOI: 10.1007/978-1-0716-3605-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
In this chapter, we describe a method for analyzing both recombinant and plasma-derived alpha 1 antitrypsin and its oligomers by means of native ion mobility mass spectrometry. Our experimental workflow can be applied to other variants of alpha 1 antitrypsin and its oligomers as well as being used to probe their interactions with small molecules in the gas phase.
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Affiliation(s)
- Sarah Vickers
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, UK
| | - James Irving
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, UK
- UCL Respiratory, University College London, London, UK
| | - David A Lomas
- UCL Respiratory, University College London, London, UK
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, UK.
- Institute of Structural and Molecular Biology, Birkbeck College, University of London, London, UK.
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3
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Papiris SA, Parmaxidis A, Theotokoglou S, Tsakiraki Z, Veith M, Panagiotou A, Pappa V, Kallieri M, Mornex JF, Katoulis AC, Haritos D, Panayiotides IG, Manali ED. Diffuse panniculitis in a teenage male with ZZ α 1-antitrypsin deficiency. ERJ Open Res 2023; 9:00546-2022. [PMID: 36891069 PMCID: PMC9986751 DOI: 10.1183/23120541.00546-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/17/2022] [Indexed: 01/27/2023] Open
Abstract
Diffuse panniculitis is a rare manifestation of α1-ATD, albeit perhaps the most fulminant and life-threatening complication, associated usually with ZZ phenotype. Intravenous α1-AT treatment is lifesaving. https://bit.ly/3EDmCzT.
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Affiliation(s)
- Spyros A Papiris
- 2nd Pulmonary Medicine Department, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,These authors contributed equally
| | - Anthimos Parmaxidis
- 2nd Propaedeutic Department of Internal Medicine, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,These authors contributed equally
| | - Sofia Theotokoglou
- 2nd Department of Dermatology and Venereology, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Zoe Tsakiraki
- 2nd Second Department of Pathology, National and Kapodistrian University of Athens, Attikon University General Hospital, Athens, Greece
| | - Martina Veith
- Department of Medicine, Pulmonary and Critical Care Medicine, UKGM, Member of the German Center for Lung Research (DZL), Marburg, Germany
| | - Aikaterini Panagiotou
- 2nd Propaedeutic Department of Internal Medicine, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Vasiliki Pappa
- 2nd Propaedeutic Department of Internal Medicine, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Kallieri
- 2nd Pulmonary Medicine Department, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Jean-François Mornex
- Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Pneumologie, Centre National de Référence des Maladies Pulmonaires Rares, INSERM CIC 1407, Lyon, France.,Université de Lyon, Université de Lyon, Université Lyon 1, UMR754 INRAE, IVPC, Lyon France
| | - Alexander C Katoulis
- 2nd Department of Dermatology and Venereology, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Dionysios Haritos
- 2nd Propaedeutic Department of Internal Medicine, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,These authors contributed equally
| | - Ioannis G Panayiotides
- 2nd Second Department of Pathology, National and Kapodistrian University of Athens, Attikon University General Hospital, Athens, Greece.,These authors contributed equally
| | - Effrosyni D Manali
- 2nd Pulmonary Medicine Department, General University Hospital Attikon, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,These authors contributed equally
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4
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Wiesemann GS, Oshins RA, Flagg TO, Brantly ML. Novel SERPINA1 Alleles Identified through a Large Alpha-1 Antitrypsin Deficiency Screening Program and Review of Known Variants. CHRONIC OBSTRUCTIVE PULMONARY DISEASES (MIAMI, FLA.) 2023; 10:7-21. [PMID: 36367950 PMCID: PMC9995231 DOI: 10.15326/jcopdf.2022.0321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The SERPINA1 gene encodes the serine protease inhibitor alpha-1 antitrypsin (AAT) and is located on chromosome 14q31-32.3 in a cluster of homologous genes likely formed by exon duplication. AAT has a variety of anti-inflammatory properties. Its clinical relevance is best illustrated by the genetic disease alpha-1 antitrypsin deficiency (AATD) which is associated with an increased risk for chronic obstructive pulmonary disease (COPD) and cirrhosis. While 2 single nucleotide polymorphisms (SNPs) , S and Z, are responsible for more than 95% of all individuals with AATD, there are a number of rare variants associated with deficiency and dysfunction, as well as those associated with normal levels and function. Our laboratory has identified a number of novel AAT alleles that we report in this manuscript. We screened more than 500,000 individuals for AATD alleles through our testing program over the past 20 years. The characterization of these alleles was accomplished by DNA sequencing, measurement of AAT plasma levels and isoelectric focusing at pH 4-5. We report 22 novel AAT alleles discovered through our screening programs, such as Zlittle rock and QOchillicothe, and review the current literature of known AAT genetic variants.
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Affiliation(s)
- Gayle S Wiesemann
- University of Florida College of Medicine, Gainesville, Florida, United States
| | - Regina A Oshins
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
| | - Tammy O Flagg
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
| | - Mark L Brantly
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, University of Florida, Gainesville, Florida, United States
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5
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Liu X, Kouassi KGW, Vanbever R, Dumoulin M. Impact of the PEG length and PEGylation site on the structural, thermodynamic, thermal, and proteolytic stability of mono-PEGylated alpha-1 antitrypsin. Protein Sci 2022; 31:e4392. [PMID: 36040264 PMCID: PMC9375436 DOI: 10.1002/pro.4392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/08/2022] [Accepted: 07/11/2022] [Indexed: 11/11/2022]
Abstract
Conjugation to polyethylene glycol (PEG) is a widely used approach to improve the therapeutic value of proteins essentially by prolonging their body residence time. PEGylation may however induce changes in the structure and/or the stability of proteins and thus on their function(s). The effects of PEGylation on the thermodynamic stability can either be positive (stabilization), negative (destabilization), or neutral (no effect). Moreover, various factors such as the PEG length and PEGylation site can influence the consequences of PEGylation on the structure and stability of proteins. In this study, the effects of PEGylation on the structure, stability, and polymerization of alpha1-antitrypsin (AAT) were investigated, using PEGs with different lengths, different structures (linear or 2-armed) and different linking chemistries (via amine or thiol) at two distinct positions of the sequence. The results show that whatever the size, position, and structure of PEG chains, PEGylation (a) does not induce significant changes in AAT structure (either at the secondary or tertiary level); (b) does not alter the stability of the native protein upon both chemical- and heat-induced denaturation; and (c) does not prevent AAT to fully refold and recover its activity following chemical denaturation. However, the propensity of AAT to aggregate upon heat treatment was significantly decreased by PEGylation, although PEGylation did not prevent the irreversible inactivation of the enzyme. Moreover, conjugation to PEG, especially 2-armed 40 kDa PEG, greatly improved the proteolytic resistance of AAT. PEGylation of AAT could be a promising strategy to prolong its half-life after infusion in AAT-deficient patients and thereby decrease the frequency of infusions.
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Affiliation(s)
- Xiao Liu
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Kobenan G. W. Kouassi
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Rita Vanbever
- Advanced Drug Delivery and BiomaterialsLouvain Drug Research Institute, Université catholique de Louvain (UCLouvain)BrusselsBelgium
| | - Mireille Dumoulin
- Department of Life SciencesInBios, Center for Protein Engineering, Nanobodies to Explore Protein Structure and Functions, University of LiègeLiègeBelgium
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6
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Plessa E, Chu LP, Chan SHS, Thomas OL, Cassaignau AME, Waudby CA, Christodoulou J, Cabrita LD. Nascent chains can form co-translational folding intermediates that promote post-translational folding outcomes in a disease-causing protein. Nat Commun 2021; 12:6447. [PMID: 34750347 PMCID: PMC8576036 DOI: 10.1038/s41467-021-26531-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 10/01/2021] [Indexed: 01/16/2023] Open
Abstract
During biosynthesis, proteins can begin folding co-translationally to acquire their biologically-active structures. Folding, however, is an imperfect process and in many cases misfolding results in disease. Less is understood of how misfolding begins during biosynthesis. The human protein, alpha-1-antitrypsin (AAT) folds under kinetic control via a folding intermediate; its pathological variants readily form self-associated polymers at the site of synthesis, leading to alpha-1-antitrypsin deficiency. We observe that AAT nascent polypeptides stall during their biosynthesis, resulting in full-length nascent chains that remain bound to ribosome, forming a persistent ribosome-nascent chain complex (RNC) prior to release. We analyse the structure of these RNCs, which reveals compacted, partially-folded co-translational folding intermediates possessing molten-globule characteristics. We find that the highly-polymerogenic mutant, Z AAT, forms a distinct co-translational folding intermediate relative to wild-type. Its very modest structural differences suggests that the ribosome uniquely tempers the impact of deleterious mutations during nascent chain emergence. Following nascent chain release however, these co-translational folding intermediates guide post-translational folding outcomes thus suggesting that Z's misfolding is initiated from co-translational structure. Our findings demonstrate that co-translational folding intermediates drive how some proteins fold under kinetic control, and may thus also serve as tractable therapeutic targets for human disease.
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Affiliation(s)
- Elena Plessa
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Lien P Chu
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Sammy H S Chan
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Oliver L Thomas
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Anaïs M E Cassaignau
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Christopher A Waudby
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - John Christodoulou
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK. .,School of Crystallography, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK.
| | - Lisa D Cabrita
- Institute of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, UK.
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7
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Proteomics of Multiple Sclerosis: Inherent Issues in Defining the Pathoetiology and Identifying (Early) Biomarkers. Int J Mol Sci 2021; 22:ijms22147377. [PMID: 34298997 PMCID: PMC8306353 DOI: 10.3390/ijms22147377] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 02/06/2023] Open
Abstract
Multiple Sclerosis (MS) is a demyelinating disease of the human central nervous system having an unconfirmed pathoetiology. Although animal models are used to mimic the pathology and clinical symptoms, no single model successfully replicates the full complexity of MS from its initial clinical identification through disease progression. Most importantly, a lack of preclinical biomarkers is hampering the earliest possible diagnosis and treatment. Notably, the development of rationally targeted therapeutics enabling pre-emptive treatment to halt the disease is also delayed without such biomarkers. Using literature mining and bioinformatic analyses, this review assessed the available proteomic studies of MS patients and animal models to discern (1) whether the models effectively mimic MS; and (2) whether reasonable biomarker candidates have been identified. The implication and necessity of assessing proteoforms and the critical importance of this to identifying rational biomarkers are discussed. Moreover, the challenges of using different proteomic analytical approaches and biological samples are also addressed.
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8
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Ronzoni R, Ferrarotti I, D’Acunto E, Balderacchi AM, Ottaviani S, Lomas DA, Irving JA, Miranda E, Fra A. The Importance of N186 in the Alpha-1-Antitrypsin Shutter Region Is Revealed by the Novel Bologna Deficiency Variant. Int J Mol Sci 2021; 22:5668. [PMID: 34073489 PMCID: PMC8198886 DOI: 10.3390/ijms22115668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/18/2021] [Accepted: 05/20/2021] [Indexed: 11/17/2022] Open
Abstract
Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.
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Affiliation(s)
- Riccardo Ronzoni
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London WC1E 6JF, UK; (D.A.L.); (J.A.I.)
| | - Ilaria Ferrarotti
- Pneumology Unit, Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy; (I.F.); (A.M.B.); (S.O.)
| | - Emanuela D’Acunto
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of Rome, 00185 Rome, Italy; (E.D.); (E.M.)
| | - Alice M. Balderacchi
- Pneumology Unit, Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy; (I.F.); (A.M.B.); (S.O.)
| | - Stefania Ottaviani
- Pneumology Unit, Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Department of Internal Medicine and Therapeutics, IRCCS San Matteo Hospital Foundation, University of Pavia, 27100 Pavia, Italy; (I.F.); (A.M.B.); (S.O.)
| | - David A. Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London WC1E 6JF, UK; (D.A.L.); (J.A.I.)
| | - James A. Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London WC1E 6JF, UK; (D.A.L.); (J.A.I.)
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of Rome, 00185 Rome, Italy; (E.D.); (E.M.)
- Italian Pasteur Institute—Cenci Bolognetti Foundation, Sapienza University of Rome, 00185 Rome, Italy
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, viale Europa 11, 25123 Brescia, Italy
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9
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Lomas DA, Irving JA, Arico‐Muendel C, Belyanskaya S, Brewster A, Brown M, Chung C, Dave H, Denis A, Dodic N, Dossang A, Eddershaw P, Klimaszewska D, Haq I, Holmes DS, Hutchinson JP, Jagger AM, Jakhria T, Jigorel E, Liddle J, Lind K, Marciniak SJ, Messer J, Neu M, Olszewski A, Ordonez A, Ronzoni R, Rowedder J, Rüdiger M, Skinner S, Smith KJ, Terry R, Trottet L, Uings I, Wilson S, Zhu Z, Pearce AC. Development of a small molecule that corrects misfolding and increases secretion of Z α 1 -antitrypsin. EMBO Mol Med 2021; 13:e13167. [PMID: 33512066 PMCID: PMC7933930 DOI: 10.15252/emmm.202013167] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/23/2023] Open
Abstract
Severe α1 -antitrypsin deficiency results from the Z allele (Glu342Lys) that causes the accumulation of homopolymers of mutant α1 -antitrypsin within the endoplasmic reticulum of hepatocytes in association with liver disease. We have used a DNA-encoded chemical library to undertake a high-throughput screen to identify small molecules that bind to, and stabilise Z α1 -antitrypsin. The lead compound blocks Z α1 -antitrypsin polymerisation in vitro, reduces intracellular polymerisation and increases the secretion of Z α1 -antitrypsin threefold in an iPSC model of disease. Crystallographic and biophysical analyses demonstrate that GSK716 and related molecules bind to a cryptic binding pocket, negate the local effects of the Z mutation and stabilise the bound state against progression along the polymerisation pathway. Oral dosing of transgenic mice at 100 mg/kg three times a day for 20 days increased the secretion of Z α1 -antitrypsin into the plasma by sevenfold. There was no observable clearance of hepatic inclusions with respect to controls over the same time period. This study provides proof of principle that "mutation ameliorating" small molecules can block the aberrant polymerisation that underlies Z α1 -antitrypsin deficiency.
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Affiliation(s)
- David A Lomas
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
| | - James A Irving
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
| | | | | | | | | | | | | | | | | | | | | | | | - Imran Haq
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
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10
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Quinn M, Ellis P, Pye A, Turner AM. Obstacles to Early Diagnosis and Treatment of Alpha-1 Antitrypsin Deficiency: Current Perspectives. Ther Clin Risk Manag 2020; 16:1243-1255. [PMID: 33364772 PMCID: PMC7751439 DOI: 10.2147/tcrm.s234377] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/30/2020] [Indexed: 11/23/2022] Open
Abstract
This review summarizes the current research and outlooks regarding the obstacles to diagnosing and treating early alpha-1-antitrypsin deficiency (AATD). It draws on prior systematic reviews and expert surveys to discover precisely what difficulties exist in early diagnosis and treatment of AATD and elucidate potential solutions to ease these difficulties. The perceived rarity of AATD may translate to a condition poorly understood by primary care physicians, and even many respiratory physicians, which results in opportunities for diagnosis being missed, especially in mild or asymptomatic patients. There are diagnostic techniques involving biomarkers and home testing methods which could improve the rate of early diagnosis. With respect to treatment, AATD involves treating two separate pathologies, lung disease and liver disease. The only specific AATD treatment, augmentation therapy, has proven ability in treating lung disease but not liver disease. Alpha-1-antitrypsin (AAT) synthesized in the liver can form damaging polymers that also result in reduced circulating AAT levels and, whilst liver transplantation is used to effectively treat AATD, it is inappropriate in early disease. Novel therapeutic areas such as gene editing and increasing autophagy are therefore being researched as future treatments. Ultimately, diagnosis and treatment are intrinsically linked in AATD, with earlier diagnosis leading to better treatment options and thus better patient outcomes.
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Affiliation(s)
- Mark Quinn
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Paul Ellis
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Anita Pye
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Alice M Turner
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK.,University Hospitals Birmingham, Birmingham, UK
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11
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Jagger AM, Waudby CA, Irving JA, Christodoulou J, Lomas DA. High-resolution ex vivo NMR spectroscopy of human Z α 1-antitrypsin. Nat Commun 2020; 11:6371. [PMID: 33311470 PMCID: PMC7732992 DOI: 10.1038/s41467-020-20147-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 11/15/2020] [Indexed: 01/18/2023] Open
Abstract
Genetic mutations predispose the serine protease inhibitor α1-antitrypsin to misfolding and polymerisation within hepatocytes, causing liver disease and chronic obstructive pulmonary disease. This misfolding occurs via a transiently populated intermediate state, but our structural understanding of this process is limited by the instability of recombinant α1-antitrypsin variants in solution. Here we apply NMR spectroscopy to patient-derived samples of α1-antitrypsin at natural isotopic abundance to investigate the consequences of disease-causing mutations, and observe widespread chemical shift perturbations for methyl groups in Z AAT (E342K). By comparison with perturbations induced by binding of a small-molecule inhibitor of misfolding we conclude that they arise from rapid exchange between the native conformation and a well-populated intermediate state. The observation that this intermediate is stabilised by inhibitor binding suggests a paradoxical approach to the targeted treatment of protein misfolding disorders, wherein the stabilisation of disease-associated states provides selectivity while inhibiting further transitions along misfolding pathways.
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Affiliation(s)
- Alistair M Jagger
- UCL Respiratory, Rayne Institute, University College London, London, WC1E 6JF, UK
- Institute of Structural and Molecular Biology, University College London and School of Crystallography, Birkbeck College, University of London, Gower Street, London, WC1E 6BT, UK
| | - Christopher A Waudby
- Institute of Structural and Molecular Biology, University College London and School of Crystallography, Birkbeck College, University of London, Gower Street, London, WC1E 6BT, UK
| | - James A Irving
- UCL Respiratory, Rayne Institute, University College London, London, WC1E 6JF, UK.
- Institute of Structural and Molecular Biology, University College London and School of Crystallography, Birkbeck College, University of London, Gower Street, London, WC1E 6BT, UK.
| | - John Christodoulou
- Institute of Structural and Molecular Biology, University College London and School of Crystallography, Birkbeck College, University of London, Gower Street, London, WC1E 6BT, UK.
| | - David A Lomas
- UCL Respiratory, Rayne Institute, University College London, London, WC1E 6JF, UK.
- Institute of Structural and Molecular Biology, University College London and School of Crystallography, Birkbeck College, University of London, Gower Street, London, WC1E 6BT, UK.
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12
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Belchamber KBR, Walker EM, Stockley RA, Sapey E. Monocytes and Macrophages in Alpha-1 Antitrypsin Deficiency. Int J Chron Obstruct Pulmon Dis 2020; 15:3183-3192. [PMID: 33311976 PMCID: PMC7725100 DOI: 10.2147/copd.s276792] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/14/2020] [Indexed: 12/14/2022] Open
Abstract
Alpha-1 antitrypsin deficiency (AATD) is a genetic condition characterised by low circulating levels of alpha-1 antitrypsin (AAT), a serine proteinase inhibitor. The most common deficiency variants are the S and Z mutations, which cause the accumulation of misfolded AAT in hepatocytes resulting in endoplasmic reticular stress and insufficient release of AAT into the circulation (<11μmol/L). This leads to liver disease, as well as an increased risk of emphysema due to unopposed proteolytic activity of neutrophil-derived serine proteinases in the lungs. AATD has been traditionally viewed as an inflammatory disorder caused directly by a proteinase-antiproteinase imbalance in the lung, but increasing evidence suggests that low AAT levels may affect other cellular functions. Recently, AAT polymers have been identified in both monocytes and macrophages from AATD patients and evidence is building that these cells may also play a role in the development of AATD lung disease. Alveolar macrophages are phagocytic cells that are important in the lung immune response but are also implicated in driving inflammation. This review explores the potential implications of monocyte and macrophage involvement in non-liver AAT synthesis and the pathophysiology of AATD lung disease.
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Affiliation(s)
- Kylie B R Belchamber
- Birmingham Acute Care Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Eloise M Walker
- Birmingham Acute Care Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Robert A Stockley
- Birmingham Acute Care Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
| | - Elizabeth Sapey
- Birmingham Acute Care Research Group, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK
- NIHR Clinical Research Facility Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
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13
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Faull SV, Elliston ELK, Gooptu B, Jagger AM, Aldobiyan I, Redzej A, Badaoui M, Heyer-Chauhan N, Rashid ST, Reynolds GM, Adams DH, Miranda E, Orlova EV, Irving JA, Lomas DA. The structural basis for Z α 1-antitrypsin polymerization in the liver. SCIENCE ADVANCES 2020; 6:6/43/eabc1370. [PMID: 33087346 PMCID: PMC7577719 DOI: 10.1126/sciadv.abc1370] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 09/08/2020] [Indexed: 05/22/2023]
Abstract
The serpinopathies are among a diverse set of conformational diseases that involve the aberrant self-association of proteins into ordered aggregates. α1-Antitrypsin deficiency is the archetypal serpinopathy and results from the formation and deposition of mutant forms of α1-antitrypsin as "polymer" chains in liver tissue. No detailed structural analysis has been performed of this material. Moreover, there is little information on the relevance of well-studied artificially induced polymers to these disease-associated molecules. We have isolated polymers from the liver tissue of Z α1-antitrypsin homozygotes (E342K) who have undergone transplantation, labeled them using a Fab fragment, and performed single-particle analysis of negative-stain electron micrographs. The data show structural equivalence between heat-induced and ex vivo polymers and that the intersubunit linkage is best explained by a carboxyl-terminal domain swap between molecules of α1-antitrypsin.
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Affiliation(s)
- Sarah V Faull
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
| | - Emma L K Elliston
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - Bibek Gooptu
- Leicester Institute of Structural and Chemical Biology, University of Leicester, Henry Wellcome Building, Lancaster Road, Leicester LE1 7HB, UK
- National Institute for Health Research (NIHR) Leicester BRC-Respiratory, Leicester, UK
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, University of London, London WC1E 7HX, UK
| | - Alistair M Jagger
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - Ibrahim Aldobiyan
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - Adam Redzej
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, University of London, London WC1E 7HX, UK
| | - Magd Badaoui
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
| | - Nina Heyer-Chauhan
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - S Tamir Rashid
- Centre for Stem Cells and Regenerative Medicine and Institute for Liver Studies, King's College London, London WC2R 2LS, UK
| | - Gary M Reynolds
- Centre for Liver Research and NIHR Birmingham Liver Biomedical Research Unit, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK
| | - David H Adams
- Centre for Liver Research and NIHR Birmingham Liver Biomedical Research Unit, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK
| | - Elena Miranda
- Department of Biology and Biotechnologies "Charles Darwin" and Pasteur Institute-Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy
| | - Elena V Orlova
- Institute of Structural and Molecular Biology, Birkbeck College, Malet Street, University of London, London WC1E 7HX, UK
| | - James A Irving
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK.
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - David A Lomas
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK.
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
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14
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Laffranchi M, Elliston EL, Miranda E, Perez J, Ronzoni R, Jagger AM, Heyer-Chauhan N, Brantly ML, Fra A, Lomas DA, Irving JA. Intrahepatic heteropolymerization of M and Z alpha-1-antitrypsin. JCI Insight 2020; 5:135459. [PMID: 32699193 PMCID: PMC7453904 DOI: 10.1172/jci.insight.135459] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/17/2020] [Indexed: 12/21/2022] Open
Abstract
The α-1-antitrypsin (or alpha-1-antitrypsin, A1AT) Z variant is the primary cause of severe A1AT deficiency and forms polymeric chains that aggregate in the endoplasmic reticulum of hepatocytes. Around 2%-5% of Europeans are heterozygous for the Z and WT M allele, and there is evidence of increased risk of liver disease when compared with MM A1AT individuals. We have shown that Z and M A1AT can copolymerize in cell models, but there has been no direct observation of heteropolymer formation in vivo. To this end, we developed a monoclonal antibody (mAb2H2) that specifically binds to M in preference to Z A1AT, localized its epitope using crystallography to a region perturbed by the Z (Glu342Lys) substitution, and used Fab fragments to label polymers isolated from an MZ heterozygote liver explant. Glu342 is critical to the affinity of mAb2H2, since it also recognized the mild S-deficiency variant (Glu264Val) present in circulating polymers from SZ heterozygotes. Negative-stain electron microscopy of the Fab2H2-labeled liver polymers revealed that M comprises around 6% of the polymer subunits in the MZ liver sample. These data demonstrate that Z A1AT can form heteropolymers with polymerization-inert variants in vivo with implications for liver disease in heterozygous individuals.
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Affiliation(s)
- Mattia Laffranchi
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.,UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Emma Lk Elliston
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Elena Miranda
- Department of Biology and Biotechnologies 'Charles Darwin' and Pasteur Institute - Cenci Bolognetti Foundation, Sapienza University of Rome, Rome, Italy
| | - Juan Perez
- Departamento de Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Campus de Teatinos, Universidad de Malaga, Malaga, Spain
| | - Riccardo Ronzoni
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Alistair M Jagger
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Nina Heyer-Chauhan
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Mark L Brantly
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
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15
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Abstract
A huge number of proteins that occur in the body have to be folded into a specific shape in order to become functional. Proteins are made up of chains of amino acids and the folding process is exquisitely complex. When this folding process is inhibited, the respective protein is referred to as being misfolded and nonfunctional. So the hypothesis that follows is in regard to the diseases that are caused by the misfolding of vital proteins and their reported relationship with thiamin metabolism. These diseases are termed proteopathies and there are at least 50 different conditions in which the mechanism is importantly related to a misfolded protein. In the brain, thiamin deficiency causes a cascade of events involving mild impairment of oxidative metabolism, neuroinflammation and neurodegeneration, including the pathology of Alzheimer's disease, Parkinson's and Huntington's diseases, all of which are examples of proteopathies. Prion diseases are fatal neurodegenerative disorders related to the conformational alteration of the prion protein (PrP C) into a pathogenic and protease-resistant isoform (PrPSc). The physiological form (PrP C) is a cell surface glycoprotein expressed mainly in the central nervous system. Despite numerous efforts to elucidate its role, the exact biological function remains unknown. Prion-induced diseases, due to the conformational change in the protein, are a global health problem, with lack of effective therapy and 100% mortality. Thiamin and its derivatives bind the prion protein and intermolecular actions have been noted between thiamin and other thiamin-binding proteins, although the exact importance of this is conjectural.
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Affiliation(s)
- Derrick Lonsdale
- Cleveland Clinic, 28575 Westlake Village Dr., Westlake, OH 44145, United States.
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16
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Jaberie H, Hosseini SV, Naghibalhossaini F. Evaluation of Alpha 1-Antitrypsin for the Early Diagnosis of Colorectal Cancer. Pathol Oncol Res 2019; 26:1165-1173. [PMID: 31183614 DOI: 10.1007/s12253-019-00679-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/29/2019] [Indexed: 01/19/2023]
Abstract
Previous proteomic studies have identified alpha 1-antitrypsin (A1AT) as a potential serum biomarker for colorectal cancer (CRC). In this case-control study, we evaluated plasma A1AT concentration and activity as a biomarker for the early diagnosis of colorectal cancer in a group of 113 sporadic CRC patients. We also analyzed A1AT gene promoter methylation, and genotypes in this group of CRC patients. The plasma A1AT and CEA concentrations were measured using the nephelometric and ELISA methods, respectively. A1AT activity was determined by Trypsin Inhibitor Capacity assay. The genomic DNA from blood samples were subjected to Z and S genotype analysis using PCR-RFLP method and the gene promoter methylation in tumors and their adjacent normal tissues was determined by methylation specific-PCR assay. The plasma levels of A1AT and CEA in patients (median, 2.3 g/L and 5.96 ng/ml, respectively) were significantly higher than those in healthy controls (medians, 1.43 g/L and 2.57 ng/ml, respectively) (p = 0.0001). The plasma A1AT activity and concentrations were positively correlated with the tumor stage and well-discriminated between early and advanced stages. The A1AT activity in plasma was the most useful marker for CRC diagnosis (median 4.8 mmol/min/ml in cases vs 1.91 mmol/min/ml in controls, p = 0.0001). No deficient Z or S alleles of A1AT was observed in patients' genotype and the gene promoter tends to be more methylated in normal mucosa than in tumor tissues. We conclude that plasma A1AT activity has better sensitivity and specificity than CEA measurement for the early detection of CRC. Promoter demethylation might play a role in increasing plasma A1AT levels in CRC patients.
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Affiliation(s)
- Hajar Jaberie
- Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Zand Street, Shiraz, 7134845794, Iran.,Department of Biochemistry, School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
| | | | - Fakhraddin Naghibalhossaini
- Department of Biochemistry, School of Medicine, Shiraz University of Medical Sciences, Zand Street, Shiraz, 7134845794, Iran. .,Autoimmune Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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17
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Laffranchi M, Elliston ELK, Gangemi F, Berardelli R, Lomas DA, Irving JA, Fra A. Characterisation of a type II functionally-deficient variant of alpha-1-antitrypsin discovered in the general population. PLoS One 2019; 14:e0206955. [PMID: 30633749 PMCID: PMC6329500 DOI: 10.1371/journal.pone.0206955] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/02/2019] [Indexed: 11/23/2022] Open
Abstract
Lung disease in alpha-1-antitrypsin deficiency (AATD) results from dysregulated proteolytic activity, mainly by neutrophil elastase (HNE), in the lung parenchyma. This is the result of a substantial reduction of circulating alpha-1-antitrypsin (AAT) and the presence in the plasma of inactive polymers of AAT. Moreover, some AAT mutants have reduced intrinsic activity toward HNE, as demonstrated for the common Z mutant, as well as for other rarer variants. Here we report the identification and characterisation of the novel AAT reactive centre loop variant Gly349Arg (p.G373R) present in the ExAC database. This AAT variant is secreted at normal levels in cellular models of AATD but shows a severe reduction in anti-HNE activity. Biochemical and molecular dynamics studies suggest it exhibits unfavourable RCL presentation to cognate proteases and compromised insertion of the RCL into β-sheet A. Identification of a fully dysfunctional AAT mutant that does not show a secretory defect underlines the importance of accurate genotyping of patients with pulmonary AATD manifestations regardless of the presence of normal levels of AAT in the circulation. This subtype of disease is reminiscent of dysfunctional phenotypes in anti-thrombin and C1-inibitor deficiencies so, accordingly, we classify this variant as the first pure functionally-deficient (type II) AATD mutant.
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Affiliation(s)
- Mattia Laffranchi
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Emma L K Elliston
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Fabrizio Gangemi
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Romina Berardelli
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
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18
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Abstract
This review discusses current bottlenecks in making CRISPR-Cas9-mediated genome editing a therapeutic reality and it outlines recent strategies that aim to overcome these hurdles as well as the scope of current clinical trials that pioneer the medical translation of CRISPR-Cas9. Additionally, this review outlines the specifics of disease-modifying gene editing in recessive versus dominant genetic diseases with the focus on genetic myopathies that are exemplified by Duchenne muscular dystrophy and myotonic dystrophies.
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Affiliation(s)
- Irina Conboy
- Bioengineering, UC Berkeley, Berkeley, CA, 94720, USA
| | - Niren Murthy
- Bioengineering, UC Berkeley, Berkeley, CA, 94720, USA
| | - Jessy Etienne
- Bioengineering, UC Berkeley, Berkeley, CA, 94720, USA
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19
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Segeritz CP, Rashid ST, de Brito MC, Serra MP, Ordonez A, Morell CM, Kaserman JE, Madrigal P, Hannan NRF, Gatto L, Tan L, Wilson AA, Lilley K, Marciniak SJ, Gooptu B, Lomas DA, Vallier L. hiPSC hepatocyte model demonstrates the role of unfolded protein response and inflammatory networks in α 1-antitrypsin deficiency. J Hepatol 2018; 69:851-860. [PMID: 29879455 PMCID: PMC6562205 DOI: 10.1016/j.jhep.2018.05.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 04/25/2018] [Accepted: 05/17/2018] [Indexed: 02/02/2023]
Abstract
BACKGROUND & AIMS α1-Antitrypsin deficiency (A1ATD) is an autosomal recessive disorder caused by mutations in the SERPINA1 gene. Individuals with the Z variant (Gly342Lys) retain polymerised protein in the endoplasmic reticulum (ER) of their hepatocytes, predisposing them to liver disease. The concomitant lack of circulating A1AT also causes lung emphysema. Greater insight into the mechanisms that link protein misfolding to liver injury will facilitate the design of novel therapies. METHODS Human-induced pluripotent stem cell (hiPSC)-derived hepatocytes provide a novel approach to interrogate the molecular mechanisms of A1ATD because of their patient-specific genetic architecture and reflection of human physiology. To that end, we utilised patient-specific hiPSC hepatocyte-like cells (ZZ-HLCs) derived from an A1ATD (ZZ) patient, which faithfully recapitulated key aspects of the disease at the molecular and cellular level. Subsequent functional and "omics" comparisons of these cells with their genetically corrected isogenic-line (RR-HLCs) and primary hepatocytes/human tissue enabled identification of new molecular markers and disease signatures. RESULTS Our studies showed that abnormal A1AT polymer processing (immobilised ER components, reduced luminal protein mobility and disrupted ER cisternae) occurred heterogeneously within hepatocyte populations and was associated with disrupted mitochondrial structure, presence of the oncogenic protein AKR1B10 and two upregulated molecular clusters centred on members of inflammatory (IL-18 and Caspase-4) and unfolded protein response (Calnexin and Calreticulin) pathways. These results were validated in a second patient-specific hiPSC line. CONCLUSIONS Our data identified novel pathways that potentially link the expression of Z A1AT polymers to liver disease. These findings could help pave the way towards identification of new therapeutic targets for the treatment of A1ATD. LAY SUMMARY This study compared the gene expression and protein profiles of healthy liver cells and those affected by the inherited disease α1-antitrypsin deficiency. This approach identified specific factors primarily present in diseased samples which could provide new targets for drug development. This study also demonstrates the interest of using hepatic cells generated from human-induced pluripotent stem cells to model liver disease in vitro for uncovering new mechanisms with clinical relevance.
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Affiliation(s)
- Charis-Patricia Segeritz
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK; Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Sheikh Tamir Rashid
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK; Cambridge Institute for Medical Research, University of Cambridge, UK; Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, UK.
| | - Miguel Cardoso de Brito
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK
| | - Maria Paola Serra
- Centre for Stem Cells and Regenerative Medicine & Institute for Liver Studies, King's College London, UK
| | - Adriana Ordonez
- Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Carola Maria Morell
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK
| | - Joseph E Kaserman
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Pedro Madrigal
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK
| | - Nicholas R F Hannan
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK
| | - Laurent Gatto
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Building O, Downing Site, Cambridge CB2 1QW, UK
| | - Lu Tan
- Cambridge Institute for Medical Research, University of Cambridge, UK
| | - Andrew A Wilson
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Kathryn Lilley
- Cambridge Centre for Proteomics, Department of Biochemistry, University of Cambridge, Building O, Downing Site, Cambridge CB2 1QW, UK
| | | | - Bibek Gooptu
- NIHR Leicester BRC-Respiratory and Leicester Institute of Structural & Chemical Biology, University of Leicester, UK; ISMB/Birkbeck & UCL, University of London, UK; Division of Asthma, Allergy and Lung Biology, King's College London, UK
| | | | - Ludovic Vallier
- Wellcome Trust and MRC Cambridge Stem Cell Institute, Department of Surgery, University of Cambridge, UK; Wellcome Trust Sanger Institute, Genome Campus Hinxton, UK.
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20
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α1-Antitrypsin Polymerizes in Alveolar Macrophages of Smokers With and Without α1-Antitrypsin Deficiency. Chest 2018; 154:607-616. [DOI: 10.1016/j.chest.2018.04.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/05/2018] [Accepted: 04/24/2018] [Indexed: 12/21/2022] Open
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21
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Lomas DA. New Therapeutic Targets for Alpha-1 Antitrypsin Deficiency. CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2018; 5:233-243. [PMID: 30723781 DOI: 10.15326/jcopdf.5.4.2017.0165] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alpha-1antitrypsin deficiency (AATD) results from the intracellular polymerization and retention of mutant alpha-1antitrypsin (AAT) within the endoplasmic reticulum of hepatocytes. This causes cirrhosis whilst the deficiency of circulating AAT predisposes to early onset emphysema. This is an exciting time for researchers in the field with the development of novel therapies based on understanding the pathobiology of disease. I review here augmentation therapy to prevent the progression of lung disease and a range of approaches to treat the liver disease associated with the accumulation of mutant AAT: modifying proteostasis networks that are activated by Z AAT polymers, stimulating autophagy, small interfering RNA and small molecules to block intracellular polymerization, and stem cell technology to correct the genetic defect that underlies AATD.
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Affiliation(s)
- David A Lomas
- UCL Respiratory, Division of Medicine, University College London, United Kingdom
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22
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Giacopuzzi E, Laffranchi M, Berardelli R, Ravasio V, Ferrarotti I, Gooptu B, Borsani G, Fra A. Real-world clinical applicability of pathogenicity predictors assessed on SERPINA1
mutations in alpha-1-antitrypsin deficiency. Hum Mutat 2018; 39:1203-1213. [DOI: 10.1002/humu.23562] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/20/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023]
Affiliation(s)
- Edoardo Giacopuzzi
- Division of Biology and Genetics; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
| | - Mattia Laffranchi
- Experimental Oncology and Immunology; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
| | - Romina Berardelli
- Experimental Oncology and Immunology; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
| | - Viola Ravasio
- Division of Biology and Genetics; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
| | - Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency; Department of Internal Medicine and Therapeutics; University of Pavia; Pavia Italy
| | - Bibek Gooptu
- Leicester Institute of Structural and Chemical Biology / NIHR Leicester BRC - Respiratory; University of Leicester; Leicester UK
| | - Giuseppe Borsani
- Division of Biology and Genetics; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
| | - Annamaria Fra
- Experimental Oncology and Immunology; Department of Molecular and Translational Medicine; University of Brescia; Brescia Italy
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23
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Fei R, Zhang H, Zhong S, Xue B, Gao Y, Zhou X. Anti-inflammatory activity of a thermophilic serine protease inhibitor from extremophile Pyrobaculum neutrophilum. EUR J INFLAMM 2017. [DOI: 10.1177/1721727x17739516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Serine protease inhibitors (serpins) are a superfamily of proteins involved in many important biological processes, including inflammation. Serpins dysfunction-related diseases are mainly treated by augmentation therapy using serpins purified from human plasma. Pnserpin from hyperthermophilic archaeon Pyrobaculum neutrophilum showed protease inhibition activity and high stability. In this study, we examined the anti-inflammatory activity of Pnserpin using xylene-induced acute inflammatory model of mouse ear swelling and lipopolysaccharide (LPS)-induced murine RAW 264.7 macrophages cellular model. The inhibition of mouse ear swelling and the production of pro-inflammatory cytokines in mouse serum or in macrophages cell were used to evaluate the anti-inflammatory effect of Pnserpin. Our results showed that Pnserpin could inhibit the xylene-induced mouse ear swelling and suppress the production of pro-inflammatory cytokines in mouse serum and in LPS-induced RAW264.7 cells. This study indicated that Pnserpin might have anti-inflammatory effect in vivo and in vitro.
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Affiliation(s)
- Rui Fei
- Department of Cell Biology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Huan Zhang
- Department of Cell Biology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Sheng Zhong
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Baigong Xue
- Department of Cell Biology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Yuanqi Gao
- Department of Cell Biology, College of Basic Medical Sciences, Jilin University, Changchun, China
| | - Xiaoli Zhou
- Department of Cell Biology, College of Basic Medical Sciences, Jilin University, Changchun, China
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24
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Miranda E, Ferrarotti I, Berardelli R, Laffranchi M, Cerea M, Gangemi F, Haq I, Ottaviani S, Lomas DA, Irving JA, Fra A. The pathological Trento variant of alpha-1-antitrypsin (E75V) shows nonclassical behaviour during polymerization. FEBS J 2017; 284:2110-2126. [PMID: 28504839 PMCID: PMC5518210 DOI: 10.1111/febs.14111] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 04/26/2017] [Accepted: 05/12/2017] [Indexed: 12/11/2022]
Abstract
Severe alpha‐1‐antitrypsin deficiency (AATD) is most frequently associated with the alpha‐1‐antitrypsin (AAT) Z variant (E342K). ZZ homozygotes exhibit accumulation of AAT as polymers in the endoplasmic reticulum of hepatocytes. This protein deposition can lead to liver disease, with the resulting low circulating levels of AAT predisposing to early‐onset emphysema due to dysregulation of elastinolytic activity in the lungs. An increasing number of rare AAT alleles have been identified in patients with severe AATD, typically in combination with the Z allele. Here we report a new mutation (E75V) in a patient with severe plasma deficiency, which we designate Trento. In contrast to the Z mutant, Trento AAT was secreted efficiently when expressed in cellular models but showed compromised conformational stability. Polyacrylamide gel electrophoresis (PAGE) and ELISA‐based analyses of the secreted protein revealed the presence of oligomeric species with electrophoretic and immunorecognition profiles different from those of Z and S (E264V) AAT polymers, including reduced recognition by conformational monoclonal antibodies 2C1 and 4B12. This altered recognition was not due to direct effects on the epitope of the 2C1 monoclonal antibody which we localized between helices E and F. Structural analyses indicate the likely basis for polymer formation is the loss of a highly conserved stabilizing interaction between helix C and the posthelix I loop. These results highlight this region as important for maintaining native state stability and, when compromised, results in the formation of pathological polymers that are different from those produced by Z and S AAT.
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Affiliation(s)
- Elena Miranda
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy
| | - Ilaria Ferrarotti
- Department of Internal Medicine and Therapeutics, Pneumology Unit, University of Pavia, Italy
| | - Romina Berardelli
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Mattia Laffranchi
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Marta Cerea
- Department of Biology and Biotechnologies 'Charles Darwin', Sapienza University of Rome, Italy.,Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Fabrizio Gangemi
- Department of Molecular and Translational Medicine, University of Brescia, Italy
| | - Imran Haq
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, UK
| | - Stefania Ottaviani
- Center for Diagnosis of Inherited Alpha 1-Antitrypsin Deficiency, Pneumology Unit, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, UK
| | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, UK
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, Italy
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25
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Andersen OJ, Risør MW, Poulsen EC, Nielsen NC, Miao Y, Enghild JJ, Schiøtt B. Reactive Center Loop Insertion in α-1-Antitrypsin Captured by Accelerated Molecular Dynamics Simulation. Biochemistry 2017; 56:634-646. [PMID: 27995800 DOI: 10.1021/acs.biochem.6b00839] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protease inhibition by metastable serine protease inhibitors (serpins) is mediated by one of the largest functional intradomain conformational changes known in biology. In this extensive structural rearrangement, protease-serpin complex formation triggers cleavage of the serpin reactive center loop (RCL), its subsequent insertion into central β-sheet A, and covalent trapping of the target protease. In this study, we present the first detailed accelerated molecular dynamics simulation of the insertion of the fully cleaved RCL in α-1-antitrypsin (α1AT), the archetypal member of the family of human serpins. Our results reveal internal water pathways that allow the initial incorporation of side chains of RCL residues into the protein interior. We observed structural plasticity of the helix F (hF) element that blocks the RCL path in the native state, which is in excellent agreement with previous experimental reports. Furthermore, the simulation suggested a novel role of hF and the connected turn (thFs3A) as chaperones that support the insertion process by reducing the conformational space available to the RCL. Transient electrostatic interactions of RCL residues potentially fine-tune the serpin inhibitory activity. On the basis of our simulation, we generated the α1AT mutants K168E, E346K, and K168E/E346K and analyzed their inhibitory activity along with their intrinsic stability and heat-induced polymerization. Remarkably, the E346K mutation exhibited enhanced inhibitory activity along with an increased rate of premature structural collapse (polymerization), suggesting a significant role of E346 in the gatekeeping of the strain in the metastable native state.
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Affiliation(s)
- Ole Juul Andersen
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Chemistry, Aarhus University , Aarhus, Denmark
| | - Michael Wulff Risør
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University , Aarhus, Denmark
| | - Emil Christian Poulsen
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University , Aarhus, Denmark
| | - Niels Chr Nielsen
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Chemistry, Aarhus University , Aarhus, Denmark
| | - Yinglong Miao
- Howard Hughes Medical Institute and Department of Pharmacology, University of California at San Diego , La Jolla, California 92093, United States
| | - Jan J Enghild
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University , Aarhus, Denmark
| | - Birgit Schiøtt
- Center for Insoluble Protein Structures (inSPIN) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University , Aarhus, Denmark.,Department of Chemistry, Aarhus University , Aarhus, Denmark
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26
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Motamedi-Shad N, Jagger AM, Liedtke M, Faull SV, Nanda AS, Salvadori E, Wort JL, Kay CW, Heyer-Chauhan N, Miranda E, Perez J, Ordóñez A, Haq I, Irving JA, Lomas DA. An antibody that prevents serpin polymerisation acts by inducing a novel allosteric behaviour. Biochem J 2016; 473:3269-90. [PMID: 27407165 PMCID: PMC5264506 DOI: 10.1042/bcj20160159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/08/2016] [Accepted: 07/12/2016] [Indexed: 11/30/2022]
Abstract
Serpins are important regulators of proteolytic pathways with an antiprotease activity that involves a conformational transition from a metastable to a hyperstable state. Certain mutations permit the transition to occur in the absence of a protease; when associated with an intermolecular interaction, this yields linear polymers of hyperstable serpin molecules, which accumulate at the site of synthesis. This is the basis of many pathologies termed the serpinopathies. We have previously identified a monoclonal antibody (mAb4B12) that, in single-chain form, blocks α1-antitrypsin (α1-AT) polymerisation in cells. Here, we describe the structural basis for this activity. The mAb4B12 epitope was found to encompass residues Glu32, Glu39 and His43 on helix A and Leu306 on helix I. This is not a region typically associated with the serpin mechanism of conformational change, and correspondingly the epitope was present in all tested structural forms of the protein. Antibody binding rendered β-sheet A - on the opposite face of the molecule - more liable to adopt an 'open' state, mediated by changes distal to the breach region and proximal to helix F. The allosteric propagation of induced changes through the molecule was evidenced by an increased rate of peptide incorporation and destabilisation of a preformed serpin-enzyme complex following mAb4B12 binding. These data suggest that prematurely shifting the β-sheet A equilibrium towards the 'open' state out of sequence with other changes suppresses polymer formation. This work identifies a region potentially exploitable for a rational design of ligands that is able to dynamically influence α1-AT polymerisation.
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Affiliation(s)
- Neda Motamedi-Shad
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Alistair M. Jagger
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Maximilian Liedtke
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
| | - Sarah V. Faull
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, U.K
| | - Arjun Scott Nanda
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Enrico Salvadori
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, U.K
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, U.K
| | - Joshua L. Wort
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Christopher W.M. Kay
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
- London Centre for Nanotechnology, 17-19 Gordon Street, London WC1H 0AH, U.K
| | - Narinder Heyer-Chauhan
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’, Sapienza University of Rome, Rome 00185, Italy
| | - Juan Perez
- Departamento de Biologia Celular, Genetica y Fisiologia, Facultad de Ciencias, Campus Teatinos, Universidad de Malaga, Malaga 29071, Spain
| | - Adriana Ordóñez
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge CB2 0XY, U.K
| | - Imran Haq
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - James A. Irving
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
| | - David A. Lomas
- Centre for Respiratory Biology, UCL Respiratory, University College London, London WC1E 6JF, U.K
- Institute of Structural and Molecular Biology/Birkbeck, University of London, London WC1E 7HX, U.K
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27
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Lomas DA, Hurst JR, Gooptu B. Update on alpha-1 antitrypsin deficiency: New therapies. J Hepatol 2016; 65:413-24. [PMID: 27034252 DOI: 10.1016/j.jhep.2016.03.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/16/2016] [Accepted: 03/20/2016] [Indexed: 02/07/2023]
Abstract
α1-Antitrypsin deficiency is characterised by the misfolding and intracellular polymerisation of mutant α1-antitrypsin within the endoplasmic reticulum of hepatocytes. The retention of mutant protein causes hepatic damage and cirrhosis whilst the lack of an important circulating protease inhibitor predisposes the individuals with severe α1-antitrypsin deficiency to early onset emphysema. Our work over the past 25years has led to new paradigms for the liver and lung disease associated with α1-antitrypsin deficiency. We review here the molecular pathology of the cirrhosis and emphysema associated with α1-antitrypsin deficiency and show how an understanding of this condition provided the paradigm for a wider group of disorders that we have termed the serpinopathies. The detailed understanding of the pathobiology of α1-antitrypsin deficiency has identified important disease mechanisms to target. As a result, several novel parallel and complementary therapeutic approaches are in development with some now in clinical trials. We provide an overview of these new therapies for the liver and lung disease associated with α1-antitrypsin deficiency.
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Affiliation(s)
- David A Lomas
- UCL Respiratory, Division of Medicine, Rayne Building, University College London, UK; The London Alpha-1-Antitrypsin Deficiency Service, Royal Free London NHS Foundation Trust, London, UK; Institute of Structural and Molecular Biology, UCL/Birkbeck College, University of London, London WC1E 7HX, UK.
| | - John R Hurst
- UCL Respiratory, Division of Medicine, Rayne Building, University College London, UK; The London Alpha-1-Antitrypsin Deficiency Service, Royal Free London NHS Foundation Trust, London, UK
| | - Bibek Gooptu
- The London Alpha-1-Antitrypsin Deficiency Service, Royal Free London NHS Foundation Trust, London, UK; Institute of Structural and Molecular Biology, UCL/Birkbeck College, University of London, London WC1E 7HX, UK; Division of Asthma, Allergy and Lung Biology, King's College London, Guy's Hospital, 5th Floor, Tower Wing, London, UK
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