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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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Balderacchi AM, Bignotti M, Ottaviani S, Denardo A, Barzon V, Ben Khlifa E, Vailati G, Piloni D, Benini F, Corda L, Corsico AG, Ferrarotti I, Fra A. Quantification of circulating alpha-1-antitrypsin polymers associated with different SERPINA1 genotypes. Clin Chem Lab Med 2024; 0:cclm-2023-1348. [PMID: 38407261 DOI: 10.1515/cclm-2023-1348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
OBJECTIVES Alpha-1-antitrypsin deficiency is a genetic disorder caused by mutations in the SERPINA1 gene encoding alpha-1-antitrypsin (AAT), the major serine protease inhibitor in plasma. Reduced AAT levels are associated with elevated risk of developing emphysema mainly due to uncontrolled activity of neutrophil elastase in the lungs. The prevalent Z-AAT mutant and many rare pathogenic AAT variants also predispose to liver disease due to their accumulation as polymeric chains in hepatocytes. Part of these polymers are secreted into the bloodstream and could represent biomarkers of intra-hepatic accumulation. Moreover, being inactive, they further lower lung protection against proteases. Aim of our study is to accurately quantify the percentage of circulating polymers (CP) in a cohort of subjects with different SERPINA1 genotypes. METHODS CP concentration was measured in plasma or Dried Blood Spot (DBS) by a sensitive sandwich ELISA based on capture by the polymer-specific 2C1 monoclonal antibody. RESULTS CP were significantly elevated in patients with the prevalent PI*SZ and PI*ZZ genotypes, with considerable intra-genotype variability. Notably, higher percentage of polymers was observed in association with elevated C-reactive protein. CP levels were also increased in carriers of the Mmalton variant, and of Mprocida, I, Plowell and Mherleen in heterozygosity with Z-AAT. CONCLUSIONS These findings highlight the importance of implementing CP quantification in a clinical laboratory. Indeed, the variable amount of CP in patients with the same genotype may correlate with the variable severity of the associated lung and liver diseases. Moreover, CP can reveal the polymerogenic potential of newly discovered ultrarare AAT variants.
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Affiliation(s)
- Alice M Balderacchi
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Mattia Bignotti
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Stefania Ottaviani
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Andrea Denardo
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Valentina Barzon
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Emna Ben Khlifa
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
| | - Guido Vailati
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Davide Piloni
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Federica Benini
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Luciano Corda
- Referral Centre for Alpha-1 Antitrypsin Deficiency, 18515 Spedali Civili , Brescia, Italy
| | - Angelo G Corsico
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, UOC Pulmonology, 18631Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, 19001University of Pavia, Pavia, Italy
| | - Annamaria Fra
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, 9297University of Brescia, Brescia, Italy
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3
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Abstract
Liver disease in homozygous ZZ alpha-1 antitrypsin (AAT) deficiency occurs due to the accumulation of large quantities of AAT mutant Z protein polymers in the liver. The mutant Z protein folds improperly during biogenesis and is retained within the hepatocytes rather than appropriately secreted. These intracellular polymers trigger an injury cascade, which leads to liver injury. However, the clinical liver disease is highly variable and not all patients with this same homozygous ZZ genotype develop liver disease. Evidence suggests that genetic determinants of intracellular protein processing, among other unidentified genetic and environmental factors, likely play a role in liver disease susceptibility. Advancements made in development of new treatment strategies using siRNA technology, and other novel approaches, are promising, and multiple human liver disease trials are underway.
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Affiliation(s)
- Anandini Suri
- Division of Pediatric Gastroenetrology, Hepatology and Nutrition, Department of Pediatrics, Saint Louis University School of Medicine, SSM Health Cardinal Glennon Children's Hospital, 1465 S Grand Boulevard, St. Louis, MO 63104, USA.
| | - Dhiren Patel
- Division of Pediatric Gastroenetrology, Hepatology and Nutrition, Department of Pediatrics, Saint Louis University School of Medicine, SSM Health Cardinal Glennon Children's Hospital, 1465 S Grand Boulevard, St. Louis, MO 63104, USA
| | - Jeffrey H Teckman
- Division of Pediatric Gastroenetrology, Hepatology and Nutrition, Department of Pediatrics, Saint Louis University School of Medicine, SSM Health Cardinal Glennon Children's Hospital, 1465 S Grand Boulevard, St. Louis, MO 63104, USA
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4
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Higgins NR, Greenslade JE, Wu JJ, Miranda E, Galliciotti G, Monteiro MJ. Serpin neuropathology in the P497S UBQLN2 mouse model of ALS/FTD. Brain Pathol 2021; 31:e12948. [PMID: 33780087 PMCID: PMC8387369 DOI: 10.1111/bpa.12948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/17/2021] [Accepted: 03/08/2021] [Indexed: 01/12/2023] Open
Abstract
Accumulating evidence suggests X-linked dominant mutations in UBQLN2 cause amyotrophic lateral sclerosis (ALS) with frontotemporal dementia (FTD) through both loss- and gain-of-function mechanisms. However, the mechanisms by which the mutations cause disease are still unclear. The goal of the study was to uncover the possible pathomechanism(s) by which UBQLN2 mutations cause ALS/FTD. An analysis of proteomic changes in neuronal tissue was used to identify proteins with altered accumulation in the P497S UBQLN2 transgenic mouse model of ALS/FTD. We then used immunocytochemistry and biochemical techniques to confirm protein changes in the mutant P497S mice. Additionally, we used cell lines inactivated of UBQLN2 expression to determine whether its loss underlies the alteration in the proteins seen in P497S mice. The proteome screen identified a dramatic alteration of serine protease inhibitor (serpin) proteins in the mutant P497S animals. Double immunofluorescent staining of brain and spinal cord tissues of the mutant and control mice revealed an age-dependent change in accumulation of Serpin A1, C1, and I1 in puncta whose staining colocalized with UBQLN2 puncta in the mutant P497S mice. Serpin A1 aggregation in P497S animals was confirmed by biochemical extraction and filter retardation assays. A similar phenomenon of serpin protein aggregation was found in HeLa and NSC34 motor neuron cells with inactivated UBQLN2 expression. We found aberrant aggregation of serpin proteins, particularly Serpin A1, in the brain and spinal cord of the P497S UBQLN2 mouse model of ALS/FTD. Similar aggregation of serpin proteins was found in UBQLN2 knockout cells suggesting that serpin aggregation in the mutant P497S animals may stem from loss of UBQLN2 function. Because serpin aggregation is known to cause disease through both loss- and gain-of-function mechanisms, we speculate that their accumulation in the P497S mouse model of ALS/FTD may contribute to disease pathogenesis through similar mechanism(s).
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Affiliation(s)
- Nicole R. Higgins
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Jessie E. Greenslade
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Josephine J. Wu
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Elena Miranda
- Department of Biology and Biotechnologies ‘Charles Darwin’Pasteur Institute – Cenci Bolognetti FoundationSapienza University of RomeRomeItaly
| | - Giovanna Galliciotti
- Institute of NeuropathologyUniversity Medical Center Hamburg‐EppendorfHamburgGermany
| | - Mervyn J. Monteiro
- Program in Molecular MedicineUniversity of Maryland School of MedicineBaltimoreMDUSA
- Center for Biomedical Engineering and TechnologyDepartment of Anatomy and NeurobiologyUniversity of Maryland School of MedicineBaltimoreMDUSA
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5
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Living with the enemy: from protein-misfolding pathologies we know, to those we want to know. Ageing Res Rev 2021; 70:101391. [PMID: 34119687 DOI: 10.1016/j.arr.2021.101391] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/19/2021] [Accepted: 06/09/2021] [Indexed: 12/12/2022]
Abstract
Conformational diseases are caused by the aggregation of misfolded proteins. The risk for such pathologies develops years before clinical symptoms appear, and is higher in people with alpha-1 antitrypsin (AAT) polymorphisms. Thousands of people with alpha-1 antitrypsin deficiency (AATD) are underdiagnosed. Enemy-aggregating proteins may reside in these underdiagnosed AATD patients for many years before a pathology for AATD fully develops. In this perspective review, we hypothesize that the AAT protein could exert a new and previously unconsidered biological effect as an endogenous metal ion chelator that plays a significant role in essential metal ion homeostasis. In this respect, AAT polymorphism may cause an imbalance of metal ions, which could be correlated with the aggregation of amylin, tau, amyloid beta, and alpha synuclein proteins in type 2 diabetes mellitus (T2DM), Alzheimer's and Parkinson's diseases, respectively.
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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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7
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Raccosta S, Librizzi F, Jagger AM, Noto R, Martorana V, Lomas DA, Irving JA, Manno M. Scaling Concepts in Serpin Polymer Physics. MATERIALS 2021; 14:ma14102577. [PMID: 34063488 PMCID: PMC8156723 DOI: 10.3390/ma14102577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 01/29/2023]
Abstract
α1-Antitrypsin is a protease inhibitor belonging to the serpin family. Serpin polymerisation is at the core of a class of genetic conformational diseases called serpinopathies. These polymers are known to be unbranched, flexible, and heterogeneous in size with a beads-on-a-string appearance viewed by negative stain electron microscopy. Here, we use atomic force microscopy and time-lapse dynamic light scattering to measure polymer size and shape for wild-type (M) and Glu342→Lys (Z) α1-antitrypsin, the most common variant that leads to severe pathological deficiency. Our data for small polymers deposited onto mica and in solution reveal a power law relation between the polymer size, namely the end-to-end distance or the hydrodynamic radius, and the polymer mass, proportional to the contour length. We use the scaling concepts of polymer physics to assess that α1-antitrypsin polymers are random linear chains with a low persistence length.
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Affiliation(s)
- Samuele Raccosta
- Institute of Biophysics, National Research Council of Italy, via Ugo La Malfa 153, 90146 Palermo, Italy; (S.R.); (F.L.); (R.N.); (V.M.)
| | - Fabio Librizzi
- Institute of Biophysics, National Research Council of Italy, via Ugo La Malfa 153, 90146 Palermo, Italy; (S.R.); (F.L.); (R.N.); (V.M.)
| | - Alistair M. Jagger
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK; (A.M.J.); (D.A.L.); (J.A.I.)
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - Rosina Noto
- Institute of Biophysics, National Research Council of Italy, via Ugo La Malfa 153, 90146 Palermo, Italy; (S.R.); (F.L.); (R.N.); (V.M.)
| | - Vincenzo Martorana
- Institute of Biophysics, National Research Council of Italy, via Ugo La Malfa 153, 90146 Palermo, Italy; (S.R.); (F.L.); (R.N.); (V.M.)
| | - David A. Lomas
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK; (A.M.J.); (D.A.L.); (J.A.I.)
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - James A. Irving
- UCL Respiratory, University College London, 5 University Street, London WC1E 6JF, UK; (A.M.J.); (D.A.L.); (J.A.I.)
- Institute of Structural and Molecular Biology, University College London, Gower Street, London WC1E 6BN, UK
| | - Mauro Manno
- Institute of Biophysics, National Research Council of Italy, via Ugo La Malfa 153, 90146 Palermo, Italy; (S.R.); (F.L.); (R.N.); (V.M.)
- Correspondence:
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Ansari S, Ray A, Ali MF, Bano S, Jairajpuri MA. Contrasting conformational dynamics of β-sheet A and helix F with implications in neuroserpin inhibition and aggregation. Int J Biol Macromol 2021; 176:117-125. [PMID: 33516851 DOI: 10.1016/j.ijbiomac.2021.01.171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/18/2021] [Accepted: 01/26/2021] [Indexed: 11/25/2022]
Abstract
Neuroserpin (NS) is an inhibitory protein of serpin super family, its shutter region variants have high propensity to aggregate leading to pathological disorders like familial encephalopathy with NS inclusion bodies (FENIB). Helix F and β-sheet A of NS participate in the tissue plasminogen activator (tPA) inhibition but the mechanism is not yet completely understood. A microsecond (μs) molecular dynamics simulation of the helix F and strand 3A variants showed predominant fluctuations in the loop connecting the strands of β-sheet A. Therefore to understand the role of helix F and strand 3A of β-sheet A, cysteine was incorporated at the position N182 in stand 3A (N182C) and position W154 (W154C) in the helix F using site-directed mutagenesis. Purified variants were further labeled with Alexa Fluor488 C5 maleimide dye. Temperature dependent study using non-denaturing PAGE showed the formation of large aggregates of helix F variant W154C but not the strand 3A N182C variant. Interestingly tPA inhibition was found to be decreased in the labeled N182C with decreased tPA-complex formation as compared to labeled W154C NS variant. The fluorescence emission intensity of the labeled helix F variant W154C decreased in the presence of an increasing concentration of tPA, whereas an increase in emission intensity was observed in labeled strand 3A variant N182C, indicating more exposure of strand 3A and shielding of helix F. Taken together the data shows that helix F has a predominant role in the aggregation but a minor role in the inhibition mechanism.
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Affiliation(s)
- Shoyab Ansari
- Protein Conformation and Enzymology Lab, Department of Biosciences, Jamia Millia Islamia (A Central University), New Delhi 110025, India
| | - Arjun Ray
- Department of Computational Biology, Indraprastha Institute of Information Technology, New Delhi 110020, India
| | - Mohammad Farhan Ali
- Protein Conformation and Enzymology Lab, Department of Biosciences, Jamia Millia Islamia (A Central University), New Delhi 110025, India
| | - Shadabi Bano
- Protein Conformation and Enzymology Lab, Department of Biosciences, Jamia Millia Islamia (A Central University), New Delhi 110025, India
| | - Mohamad Aman Jairajpuri
- Protein Conformation and Enzymology Lab, Department of Biosciences, Jamia Millia Islamia (A Central University), New Delhi 110025, India.
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Seixas S, Marques PI. Known Mutations at the Cause of Alpha-1 Antitrypsin Deficiency an Updated Overview of SERPINA1 Variation Spectrum. APPLICATION OF CLINICAL GENETICS 2021; 14:173-194. [PMID: 33790624 PMCID: PMC7997584 DOI: 10.2147/tacg.s257511] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/24/2021] [Indexed: 12/12/2022]
Abstract
Alpha-1-Antitrypsin deficiency (AATD), caused by SERPINA1 mutations, is one of the most prevalent Mendelian disorders among individuals of European descend. However, this condition, which is characterized by reduced serum levels of alpha-1-antitrypsin (AAT) and associated with increased risks of pulmonary emphysema and liver disease in both children and adults, remains frequently underdiagnosed. AATD clinical manifestations are often correlated with two pathogenic variants, the Z allele (p.Glu342Lys) and the S allele (p.Glu264Val), which can be combined in severe ZZ or moderate SZ risk genotypes. Yet, screenings of AATD cases and large sequencing efforts carried out in both control and disease populations are disclosing outstanding numbers of rare SERPINA1 variants (>500), including many pathogenic and other likely deleterious mutations. Generally speaking, pathogenic variants can be subdivided into either loss- or gain-of-function according to their pathophysiological effects. In AATD, the loss-of-function is correlated with an uncontrolled activity of elastase by its natural inhibitor, the AAT. This phenomenon can result from the absence of circulating AAT (null alleles), poor AAT secretion from hepatocytes (deficiency alleles) or even from a modified inhibitory activity (dysfunctional alleles). On the other hand, the gain-of-function is connected with the formation of AAT polymers and their switching on of cellular stress and inflammatory responses (deficiency alleles). Less frequently, the gain-of-function is related to a modified protease affinity (dysfunctional alleles). Here, we revisit SERPINA1 mutation spectrum, its origins and population history with a greater emphasis on variants fitting the aforementioned processes of AATD pathogenesis. Those were selected based on their clinical significance and wider geographic distribution. Moreover, we also provide some directions for future studies of AATD clinically heterogeneity and comprehensive diagnosis.
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Affiliation(s)
- Susana Seixas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
| | - Patricia Isabel Marques
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
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10
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Abstract
Alpha1-antitrypsin deficiency (A1ATD) is an inherited cause of chronic liver disease. It is inherited in an autosomal codominant pattern with each inherited allele expressed in the formation of the final protein, which is primarily produced in hepatocytes. The disease usually occurs in pediatric and elderly populations. The disease occurs with the accumulation of abnormal protein polymers within hepatocytes that can induce liver injury and fibrosis. It is a commonly under-recognized and underdiagnosed condition. Patients diagnosed with the disease should be regularly monitored for the development of liver disease. Liver transplant is of proven benefit in A1ATD liver disease.
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Affiliation(s)
- Vignan Manne
- Sunrise Health Consortium GME, 2880 North Tenaya Way, Las Vegas, NV 89128, USA
| | - Kris V Kowdley
- 3216 Northeast 45th Place Suite 212, Seattle, WA 98105, USA.
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Bouchecareilh M. Alpha-1 Antitrypsin Deficiency-Mediated Liver Toxicity: Why Do Some Patients Do Poorly? What Do We Know So Far? CHRONIC OBSTRUCTIVE PULMONARY DISEASES (MIAMI, FLA.) 2020; 7:172-181. [PMID: 32558486 PMCID: PMC7857713 DOI: 10.15326/jcopdf.7.3.2019.0148] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/11/2019] [Indexed: 02/08/2023]
Abstract
Alpha-1 antitrypsin deficiency (AATD) is a rare genetic disease caused by mutations in the SERPINA1 gene and is associated with a decreased level of circulating alpha-1 antitrypsin (AAT). Among all the known mutations in the SERPINA1 gene, homozygous for the Z allele is well-known to result in both lung and liver disease. Unlike the lung injury that occurs in adulthood with the environment (notably, tobacco) as a co-factor, the hepatic damage is more complicated. Despite a common underlying gene mutation, the liver disease associated with AATD presents a considerable variability in the age-of-onset and severity, ranging from transient neonatal cholestasis (in early childhood) to cirrhosis and liver cancer (in childhood and adulthood). Given that all the cofactors- genetics and/or environmental- have not been fully identified, it is still impossible to predict which individuals with AATD may develop severe liver disease. The discovery of these modifiers represents the major challenge for the detection, diagnosis, and development of new therapies to provide alternative options to liver transplantation. The aim of this current review is to provide an updated overview of our knowledge on why some AATD patients associated with liver damage progress poorly.
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Affiliation(s)
- Marion Bouchecareilh
- National Institute of Health and Medical Research (INSERM), National Center for Scientific Research (CNRS), University Bordeaux, Bordeaux Research In Translational Oncology, BaRITOn, Bordeaux, France
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Wang C, Zhao P, Sun S, Teckman J, Balch WE. Leveraging Population Genomics for Individualized Correction of the Hallmarks of Alpha-1 Antitrypsin Deficiency. CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2020; 7:224-246. [PMID: 32726074 DOI: 10.15326/jcopdf.7.3.2019.0167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Deep medicine is rapidly moving towards a high-definition approach for therapeutic management of the patient as an individual given the rapid progress of genome sequencing technologies and machine learning algorithms. While considered a monogenic disease, alpha-1 antitrypsin (AAT) deficiency (AATD) patients present with complex and variable phenotypes we refer to as the "hallmarks of AATD" that involve distinct molecular mechanisms in the liver, plasma and lung tissues, likely due to both coding and non-coding variation as well as genetic and environmental modifiers in different individuals. Herein, we briefly review the current therapeutic strategies for the management of AATD. To embrace genetic diversity in the management of AATD, we provide an overview of the disease phenotypes of AATD patients harboring different AAT variants. Linking genotypic diversity to phenotypic diversity illustrates the potential for sequence-specific regions of AAT protein fold design to play very different roles during nascent synthesis in the liver and/or function in post-liver plasma and lung environments. We illustrate how to manage diversity with recently developed machine learning (ML) approaches that bridge sequence-to-function-to-structure knowledge gaps based on the principle of spatial covariance (SCV). SCV relationships provide a deep understanding of the genotype to phenotype transformation initiated by AAT variation in the population to address the role of genetic and environmental modifiers in the individual. Embracing the complexity of AATD in the population is critical for risk management and therapeutic intervention to generate a high definition medicine approach for the patient.
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Affiliation(s)
- Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Pei Zhao
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Shuhong Sun
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Jeffrey Teckman
- Pediatrics and Biochemistry, Saint Louis University, and Cardinal Glennon Children's Medical Center, St. Louis, Missouri
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, California
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13
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Belmonte I, Nuñez A, Barrecheguren M, Esquinas C, Pons M, López-Martínez RM, Ruiz G, Blanco-Grau A, Ferrer R, Genescà J, Miravitlles M, Rodríguez-Frías F. Trends in Diagnosis of Alpha-1 Antitrypsin Deficiency Between 2015 and 2019 in a Reference Laboratory. Int J Chron Obstruct Pulmon Dis 2020; 15:2421-2431. [PMID: 33116457 PMCID: PMC7548232 DOI: 10.2147/copd.s269641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 09/28/2020] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Alpha-1 antitrypsin deficiency (AATD) remains largely underdiagnosed despite recommendations of healthcare institutions and programmes designed to increase awareness. The objective was to analyse the trends in AATD diagnosis during the last 5 years in a Spanish AATD reference laboratory. METHODS This was a retrospective revision of all alpha-1 antitrypsin (AAT) determinations undertaken in our laboratory from 2015 to 2019. We analysed the number of AAT determinations performed and described the characteristics of the individuals tested, as well as the medical specialties and the reasons for requesting AAT determination. RESULTS A total of 3507 determinations were performed, of which 5.5% corresponded to children. A significant increase in the number of AAT determinations was observed from 349 in 2015 to 872 in 2019. Among the samples, 57.6% carried an intermediate AATD (50-119 mg/dL) and 2.4% severe deficiency (<50 mg/dL). The most frequent phenotype in severe AATD individuals was PI*ZZ (78.5%), and aminotransferase levels were above normal in around 43% of children and 30% of adults. Respiratory specialists requested the highest number of AAT determinations (31.5%) followed by digestive diseases and internal medicine (27.5%) and primary care physicians (19.7%). The main reason for AAT determination in severe AATD adults was chronic obstructive pulmonary disease (41.7%), but reasons for requesting AAT determination were not reported in up to 41.7% of adults and 58.3% of children. CONCLUSION There is an increase in the frequency of AATD testing despite the rate of AAT determination remaining low. Awareness about AAT is probably increasing, but the reason for testing is not always clear.
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Affiliation(s)
- Irene Belmonte
- Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Alexa Nuñez
- Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès). Barcelona, Spain
| | - Miriam Barrecheguren
- Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Cristina Esquinas
- Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Mònica Pons
- Liver 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
| | - Rosa M López-Martínez
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Gerard Ruiz
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Albert Blanco-Grau
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Roser Ferrer
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Joan Genescà
- Liver 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
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Madrid, Spain
| | - Marc Miravitlles
- Pneumology Department, Hospital Universitari Vall d’Hebron, Vall d’Hebron Institut de Recerca (VHIR), Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
- CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain
- Correspondence: Marc Miravitlles Pneumology 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, Barcelona08035, Spain Email
| | - Francisco Rodríguez-Frías
- Department of Clinical Biochemistry, Hospital Universitari Vall d’Hebron, Vall d’Hebron Barcelona Hospital Campus, Barcelona, Spain
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14
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Ruiz M, Lacaille F, Berthiller J, Joly P, Dumortier J, Aumar M, Bridoux-Henno L, Jacquemin E, Lamireau T, Broué P, Rivet C, Belmalih A, Restier L, Chapuis-Cellier C, Bouchecareilh M, Lachaux A. Liver disease related to alpha1-antitrypsin deficiency in French children: The DEFI-ALPHA cohort. Liver Int 2019; 39:1136-1146. [PMID: 30589493 DOI: 10.1111/liv.14035] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 12/15/2018] [Accepted: 12/18/2018] [Indexed: 02/13/2023]
Abstract
BACKGROUND & AIMS To identify prognostic factors for liver disease in children with alpha-1 antitrypsin deficiency, irrespective of phenotype, using the DEFI-ALPHA cohort. METHODS Retrospective, then prospective from 2010, multicentre study including children known to have alpha-1 antitrypsin blood concentration below 0.8 g/L, born in France since 1989. Clinical and biological data were collected. Liver disease was classified as "severe" (portal hypertension, liver failure, liver transplantation or death); "moderate" (persistent abnormal liver biology without portal hypertension); and "mild/none" (normal or almost normal liver biology and native liver). Prognostic factors for severe liver disease were evaluated using a Cox semiparametric model. RESULTS In January 2017, 153 patients from 19 centres had been included; genotypes were PIZZ in 81.9%, PISZ in 8.1%, other in 10.0%. Mean ± SD follow-up was 4.7 ± 2.1 years. Half of patients had moderate liver disease. Twenty-eight children (18.3%) had severe liver disease (mean age 2.5 years, range: 0-11.6): diagnosis of alpha-1 antitrypsin deficiency was made before two months of age in 65.4%, genotypes were PIZZ in 25 (89.3%), PISZ in 2, PIMlike Z in 1, 15 children underwent liver transplantation, 1 child died at 3 years of age. Neonatal cholestasis was significantly associated with severe liver disease (P = 0.007). CONCLUSION Alpha-1 antitrypsin-deficient patients presenting with neonatal cholestasis were likely to develop severe liver disease. Some patients with non-homozygous ZZ genotype can develop severe liver disease, such as PISZ and M variants, when associated with predisposing factors. Further genetic studies will help to identify other factors involved in the development of liver complications.
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Affiliation(s)
- Mathias Ruiz
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France
| | - Florence Lacaille
- Gastroentérologie, Hépatologie et Nutrition pédiatriques, Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - Julien Berthiller
- Unité de support méthodologique du groupement Est, Pôle Information Médicale Evaluation Recherche, Hospices Civils de Lyon, Lyon, France
| | - Philippe Joly
- Inter-university Laboratory of Human Movement Science, University Lyon - University Claude Bernard Lyon 1, Villeurbanne, France.,Laboratoire de Biochimie et biologie moléculaire Grand-Est, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Jérôme Dumortier
- Hépatologie, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Madeleine Aumar
- Gastroentérologie, Hépatologie et Nutrition pédiatrique, Centre d'investigation clinique CHU Lille, University of Lille, Lille, France
| | - Laure Bridoux-Henno
- Gastroentérologie, Hépatologie et Nutrition pédiatriques, CHU Rennes, Rennes, France
| | - Emmanuel Jacquemin
- Pediatric Hepatology and Pediatric Liver Transplantation Unit and National Reference Centre for Rare Pediatric Liver Diseases, Hepatinov, Bicêtre Universitary Hospital, University of Paris-Sud, Assistance Publique-Hôpitaux de Paris, Le Kremlin Bicêtre, France.,Inserm, UMR-S1174, University of Paris-Sud, Orsay, France
| | - Thierry Lamireau
- Gastroentérologie, Hépatologie et Nutrition pédiatriques, Bordeaux, France
| | - Pierre Broué
- Gastroentérologie, Hépatologie, Nutrition, Diabétologie pédiatriques, Maladies héréditaires du métabolisme, CHU Toulouse, Toulouse, France
| | - Christine Rivet
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France
| | - Abdelouahed Belmalih
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France
| | - Lioara Restier
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France
| | - Colette Chapuis-Cellier
- Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France.,Laboratoire d'Immunologie, Centre de Biologie Sud, Hospices Civils de Lyon, Lyon, France
| | - Marion Bouchecareilh
- INSERM, UMR1053 Bordeaux Research In Translational Oncology, University Bordeaux, BaRITOn, Bordeaux, France
| | - Alain Lachaux
- Hépatologie, Gastroentérologie et Nutrition pédiatriques, Hôpital Femme Mère Enfant, Hospices Civils de Lyon, Lyon, France.,Faculté de Médecine Lyon-Est, Université Claude Bernard Lyon 1, Lyon, France
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15
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Laffranchi M, Berardelli R, Ronzoni R, Lomas DA, Fra A. Heteropolymerization of α-1-antitrypsin mutants in cell models mimicking heterozygosity. Hum Mol Genet 2019. [PMID: 29538751 DOI: 10.1093/hmg/ddy090] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The most common genotype associated with severe α-1-antitrypsin deficiency (AATD) is the Z homozygote. The Z variant (Glu342Lys) of α-1-antitrypsin (AAT) undergoes a conformational change and is retained within the endoplasmic reticulum (ER) of hepatocytes leading to the formation of ordered polymeric chains and inclusion bodies. Accumulation of mutated protein predisposes to cirrhosis whilst plasma AAT deficiency leads to emphysema. Increased risk of liver and lung disease has also been reported in heterozygous subjects who carry Z in association with the milder S allele (Glu264Val) or even with wild-type M. However, it is unknown whether Z AAT can co-polymerize with other AAT variants in vivo. We co-expressed two AAT variants, each modified by a different tag, in cell models that replicate AAT deficiency. We used pull-down assays to investigate interactions between co-expressed variants and showed that Z AAT forms heteropolymers with S and with the rare Mmalton (Phe52del) and Mwurzburg (Pro369Ser) mutants, and to a lesser extent with the wild-type protein. Heteropolymers were recognized by the 2C1 mAb that binds to Z polymers in vivo. There was increased intracellular accumulation of AAT variants when co-expressed with Z AAT, suggesting a dominant negative effect of the Z allele. The molecular interactions between S and Z AAT were confirmed by confocal microscopy showing their colocalization within dilated ER cisternae and by positivity in Proximity Ligation Assays. These results provide the first evidence of intracellular co-polymerization of AAT mutants and contribute to understanding the risk of liver disease in SZ and MZ heterozygotes.
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Affiliation(s)
- Mattia Laffranchi
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Romina Berardelli
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
| | - Riccardo Ronzoni
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.,UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London WC1E 6BT, UK
| | - Annamaria Fra
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy
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16
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Abstract
In homozygous ZZ alpha-1-antitrypsin (AAT) deficiency, the liver synthesizes large quantities of AAT mutant Z, which folds improperly during biogenesis and is retained within the hepatocytes and directed into intracellular proteolysis pathways. These intracellular polymers trigger an injury cascade, which can lead to liver injury. This is highly variable and not all patients develop liver disease. Although not fully described, there is likely a strong influence of genetic and environmental modifiers of the injury cascade and of the fibrotic response. With improved understanding of liver injury mechanisms, new strategies for treatment are now being explored.
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Affiliation(s)
- Dhiren Patel
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Saint Louis University School of Medicine, 1465 South Grand Boulevard, St Louis, MO 63104, USA
| | - Jeffrey H Teckman
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Saint Louis University School of Medicine, 1465 South Grand Boulevard, St Louis, MO 63104, USA; Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, 1465 South Grand Boulevard, St Louis, MO 63104, USA.
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17
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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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18
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Matamala N, Lara B, Gomez-Mariano G, Martínez S, Retana D, Fernandez T, Silvestre RA, Belmonte I, Rodriguez-Frias F, Vilar M, Sáez R, Iturbe I, Castillo S, Molina-Molina M, Texido A, Tirado-Conde G, Lopez-Campos JL, Posada M, Blanco I, Janciauskiene S, Martinez-Delgado B. Characterization of Novel Missense Variants of SERPINA1 Gene Causing Alpha-1 Antitrypsin Deficiency. Am J Respir Cell Mol Biol 2018; 58:706-716. [PMID: 29232161 DOI: 10.1165/rcmb.2017-0179oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The SERPINA1 gene is highly polymorphic, with more than 100 variants described in databases. SERPINA1 encodes the alpha-1 antitrypsin (AAT) protein, and severe deficiency of AAT is a major contributor to pulmonary emphysema and liver diseases. In Spanish patients with AAT deficiency, we identified seven new variants of the SERPINA1 gene involving amino acid substitutions in different exons: PiSDonosti (S+Ser14Phe), PiTijarafe (Ile50Asn), PiSevilla (Ala58Asp), PiCadiz (Glu151Lys), PiTarragona (Phe227Cys), PiPuerto Real (Thr249Ala), and PiValencia (Lys328Glu). We examined the characteristics of these variants and the putative association with the disease. Mutant proteins were overexpressed in HEK293T cells, and AAT expression, polymerization, degradation, and secretion, as well as antielastase activity, were analyzed by periodic acid-Schiff staining, Western blotting, pulse-chase, and elastase inhibition assays. When overexpressed, S+S14F, I50N, A58D, F227C, and T249A variants formed intracellular polymers and did not secrete AAT protein. Both the E151K and K328E variants secreted AAT protein and did not form polymers, although K328E showed intracellular retention and reduced antielastase activity. We conclude that deficient variants may be more frequent than previously thought and that their discovery is possible only by the complete sequencing of the gene and subsequent functional characterization. Better knowledge of SERPINA1 variants would improve diagnosis and management of individuals with AAT deficiency.
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Affiliation(s)
- Nerea Matamala
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Beatriz Lara
- 2 Respiratory Medicine Department, Coventry University Hospital, Coventry, United Kingdom
| | - Gema Gomez-Mariano
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Selene Martínez
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Diana Retana
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | - Taiomara Fernandez
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
| | | | - Irene Belmonte
- 4 Biochemistry Department, Hospital Vall d'Hebron, Barcelona, Spain
| | | | - Marçal Vilar
- 5 Instituto de Biomedicina de Valencia, Consejo Superior de Investigaciones Cientificas (CSIC), Valencia, Spain
| | - Raquel Sáez
- 6 Immunology and Genetics, Hospital Donosti, San Sebastián, Spain
| | - Igor Iturbe
- 7 Pneumology, Hospital de Zumárraga, Gipuzkoa, Spain
| | | | - María Molina-Molina
- 9 Pulmonary Medicine, Bellvitge University Hospital, Bellvitge Biomedical Research Institute (IDIBELL), Hospital de Llobregat, Barcelona, Spain
| | - Anna Texido
- 10 Pneumology, Hospital Universitari Sant Joan de Reus, Reus (Tarragona), Spain
| | - Gema Tirado-Conde
- 11 Complejo Hospitalario Universitario Granada, Parque Tecnológico de las Ciencias de la Salud, Granada, Spain
| | - Jose Luis Lopez-Campos
- 13 Consorcio Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), and
- 12 Unidad Médico-Quirúrgica de Enfermedades Respiratorias, Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocio/Universidad de Sevilla, Sevilla, Spain
| | - Manuel Posada
- 1 Molecular Genetics Unit, Instituto de Investigación de Enfermedades Raras (IIER)
- 14 Consorcio Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Ignacio Blanco
- 15 Spanish Registry of Patients with Alpha-1 Antitrypsin Deficiency (REDAAT), Spanish Society of Pneumology (SEPAR), Fundación Española de Pulmón (RESPIRA), Barcelona, Spain
| | - Sabina Janciauskiene
- 16 Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany; and
- 17 Biomedical Research in Endstage and Obstructive Lung Disease Hannover (BREATH), Member of the German Center for Lung Research (DZL), Hannover, Germany
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19
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Callea F, Giovannoni I, Francalanci P, Boldrini R, Faa G, Medicina D, Nobili V, Desmet VJ, Ishak K, Seyama K, Bellacchio E. Mineralization of alpha-1-antitrypsin inclusion bodies in Mmalton alpha-1-antitrypsin deficiency. Orphanet J Rare Dis 2018; 13:79. [PMID: 29769092 PMCID: PMC5956786 DOI: 10.1186/s13023-018-0821-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/08/2018] [Indexed: 02/07/2023] Open
Abstract
Background Alpha-1-antitrypsin (AAT) deficiency (AATD) of Z, Mmalton, Siiyama type is associated with liver storage of the mutant proteins and liver disease. The Z variant can be diagnosed on isoelectric focusing (IEF) while Mmalton and Siiyama may be missed or misdiagnosed with this technique. Therefore, molecular analysis is mandatory for their characterization. In particular, that holds true for the Mmalton variant as on IEF profile it resembles the wild M2 subtype. Methods This is a retrospective analysis involving review of medical records and of liver biopsy specimens from a series of Mmalton, Z and Siiyama Alpha-1-antitrypsin deficiency patients. The review has been implemented by additional histological stains, electron microscopic observations and 3-D modeling studies of the sites of the mutations. Results Z, Mmalton and Siiyama liver specimen contained characteristic intrahepatocytic PAS-D globules. The globules differed in the three variants as only Mmalton cases showed dark basophilic precipitates within the AAT inclusions. The precipitates were visualized in haematoxylin-eosin (H.E.) stained preparations and corresponded to calcium precipitates as demonstrated by von Kossa staining. On immunohistochemistry, ZAAT inclusions were stained by polyclonal as well as monoclonal noncommercial anti-AAT antibody (AZT11), whilst Mmalton and Siiyama inclusion bodies remained negative with the monoclonal anti-Z antibody. 3-D protein analysis allowed to predict more severe misfolding of the Mmalton molecule as compared to Z and Siiyama that could trigger anomalous interaction with endoplasmic reticulum chaperon proteins, namely calcium binding proteins. Conclusions Mmalton AAT inclusion bodies contain calcium precipitates inside them that allow the differential diagnosis with Siiyama and ZAAT inclusions in routine histological sections. The study has confirmed the specificity of the monoclonal AZT11 for the Z mutant. Thus, the combination of these two features is crucial for the distinction between the three variants and for predicting the genotype, whose confirmation would definitely require molecular analysis. Our study provides new data on the pathomorphogenesis of Mmalton inclusion bodies whose mineralization could play a central role in disease pathogenesis of Mmalton that is distinct from the Z and Siiyama variants. Calcium is known to be a major effector of cell death either via the increased intracellular concentration or the alteration of homeostasis.
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Affiliation(s)
- Francesco Callea
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy.
| | - Isabella Giovannoni
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Paola Francalanci
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Renata Boldrini
- Department of Pathology, Bambino Gesù Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Gavino Faa
- Department of Cytomorphology, University of Cagliari, Cagliari, Italy
| | - Daniela Medicina
- Department of Pathology Spedali Civili, University of Brescia, Brescia, Italy
| | - Valerio Nobili
- Hepato-metabolic Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Kamal Ishak
- Armed Forces Institute of Pathology, Washington, USA
| | - Kuniaki Seyama
- Division of Respiratory Medicine, Juntendo University Faculty of Medicine and Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-Ku, Tokyo, 113-8421, Japan
| | - Emanuele Bellacchio
- Genetic and Rare Diseases, Research Division, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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20
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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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21
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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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22
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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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23
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Bashir A, Shah NN, Hazari YM, Habib M, Bashir S, Hilal N, Banday M, Asrafuzzaman S, Fazili KM. Novel variants of SERPIN1A gene: Interplay between alpha1-antitrypsin deficiency and chronic obstructive pulmonary disease. Respir Med 2016; 117:139-49. [DOI: 10.1016/j.rmed.2016.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 04/18/2016] [Accepted: 06/06/2016] [Indexed: 12/31/2022]
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24
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Abstract
α1-Antitrypsin deficiency (A1ATD) is an inherited disorder caused by mutations in SERPINA1, leading to liver and lung disease. It is not a rare disorder but frequently goes underdiagnosed or misdiagnosed as asthma, chronic obstructive pulmonary disease (COPD) or cryptogenic liver disease. The most frequent disease-associated mutations include the S allele and the Z allele of SERPINA1, which lead to the accumulation of misfolded α1-antitrypsin in hepatocytes, endoplasmic reticulum stress, low circulating levels of α1-antitrypsin and liver disease. Currently, there is no cure for severe liver disease and the only management option is liver transplantation when liver failure is life-threatening. A1ATD-associated lung disease predominately occurs in adults and is caused principally by inadequate protease inhibition. Treatment of A1ATD-associated lung disease includes standard therapies that are also used for the treatment of COPD, in addition to the use of augmentation therapy (that is, infusions of human plasma-derived, purified α1-antitrypsin). New therapies that target the misfolded α1-antitrypsin or attempt to correct the underlying genetic mutation are currently under development.
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25
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Haq I, Irving JA, Saleh AD, Dron L, Regan-Mochrie GL, Motamedi-Shad N, Hurst JR, Gooptu B, Lomas DA. Deficiency Mutations of Alpha-1 Antitrypsin. Effects on Folding, Function, and Polymerization. Am J Respir Cell Mol Biol 2016; 54:71-80. [PMID: 26091018 DOI: 10.1165/rcmb.2015-0154oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Misfolding, polymerization, and defective secretion of functional alpha-1 antitrypsin underlies the predisposition to severe liver and lung disease in alpha-1 antitrypsin deficiency. We have identified a novel (Ala336Pro, Baghdad) deficiency variant and characterized it relative to the wild-type (M) and Glu342Lys (Z) alleles. The index case is a homozygous individual of consanguineous parentage, with levels of circulating alpha-1 antitrypsin in the moderate deficiency range, but is a biochemical phenotype that could not be classified by standard methods. The majority of the protein was present as functionally inactive polymer, and the remaining monomer was 37% active relative to the wild-type protein. These factors combined indicate an 85 to 95% functional deficiency, similar to that seen with ZZ homozygotes. Biochemical, biophysical, and computational studies further defined the molecular basis of this deficiency. These studies demonstrated that native Ala336Pro alpha-1 antitrypsin could populate the polymerogenic intermediate-and therefore polymerize-more readily than either wild-type alpha-1 antitrypsin or the Z variant. In contrast, folding was far less impaired in Ala336Pro alpha-1 antitrypsin than in the Z variant. The data are consistent with a disparate contribution by the "breach" region and "shutter" region of strand 5A to folding and polymerization mechanisms. Moreover, the findings demonstrate that, in these variants, folding efficiency does not correlate directly with the tendency to polymerize in vitro or in vivo. They therefore differentiate generalized misfolding from polymerization tendencies in missense variants of alpha-1 antitrypsin. Clinically, they further support the need to quantify loss-of-function in alpha-1 antitrypsin deficiency to individualize patient care.
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Affiliation(s)
- Imran Haq
- 1 Wolfson Institute for Biomedical Research, University College London, London, United Kingdom.,2 Institute of Structural and Molecular Biology/Birkbeck, University of London, London, United Kingdom
| | - James A Irving
- 1 Wolfson Institute for Biomedical Research, University College London, London, United Kingdom.,2 Institute of Structural and Molecular Biology/Birkbeck, University of London, London, United Kingdom
| | - Aarash D Saleh
- 3 London Alpha-1 Antitrypsin Deficiency Service, Royal Free Hospital, Pond Street, London, United Kingdom; and
| | - Louis Dron
- 3 London Alpha-1 Antitrypsin Deficiency Service, Royal Free Hospital, Pond Street, London, United Kingdom; and
| | - Gemma L Regan-Mochrie
- 1 Wolfson Institute for Biomedical Research, University College London, London, United Kingdom
| | - Neda Motamedi-Shad
- 1 Wolfson Institute for Biomedical Research, University College London, London, United Kingdom.,2 Institute of Structural and Molecular Biology/Birkbeck, University of London, London, United Kingdom
| | - John R Hurst
- 3 London Alpha-1 Antitrypsin Deficiency Service, Royal Free Hospital, Pond Street, London, United Kingdom; and
| | - Bibek Gooptu
- 2 Institute of Structural and Molecular Biology/Birkbeck, University of London, London, United Kingdom.,3 London Alpha-1 Antitrypsin Deficiency Service, Royal Free Hospital, Pond Street, London, United Kingdom; and.,4 Division of Asthma, Allergy and Lung Biology, King's College London, London, United Kingdom
| | - David A Lomas
- 1 Wolfson Institute for Biomedical Research, University College London, London, United Kingdom.,2 Institute of Structural and Molecular Biology/Birkbeck, University of London, London, United Kingdom.,3 London Alpha-1 Antitrypsin Deficiency Service, Royal Free Hospital, Pond Street, London, United Kingdom; and
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26
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Cummings EE, O’Reilly LP, King DE, Silverman RM, Miedel MT, Luke CJ, Perlmutter DH, Silverman GA, Pak SC. Deficient and Null Variants of SERPINA1 Are Proteotoxic in a Caenorhabditis elegans Model of α1-Antitrypsin Deficiency. PLoS One 2015; 10:e0141542. [PMID: 26512890 PMCID: PMC4626213 DOI: 10.1371/journal.pone.0141542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 10/10/2015] [Indexed: 12/24/2022] Open
Abstract
α1-antitrypsin deficiency (ATD) predisposes patients to both loss-of-function (emphysema) and gain-of-function (liver cirrhosis) phenotypes depending on the type of mutation. Although the Z mutation (ATZ) is the most prevalent cause of ATD, >120 mutant alleles have been identified. In general, these mutations are classified as deficient (<20% normal plasma levels) or null (<1% normal levels) alleles. The deficient alleles, like ATZ, misfold in the ER where they accumulate as toxic monomers, oligomers and aggregates. Thus, deficient alleles may predispose to both gain- and loss-of-function phenotypes. Null variants, if translated, typically yield truncated proteins that are efficiently degraded after being transiently retained in the ER. Clinically, null alleles are only associated with the loss-of-function phenotype. We recently developed a C. elegans model of ATD in order to further elucidate the mechanisms of proteotoxicity (gain-of-function phenotype) induced by the aggregation-prone deficient allele, ATZ. The goal of this study was to use this C. elegans model to determine whether different types of deficient and null alleles, which differentially affect polymerization and secretion rates, correlated to any extent with proteotoxicity. Animals expressing the deficient alleles, Mmalton, Siiyama and S (ATS), showed overall toxicity comparable to that observed in patients. Interestingly, Siiyama expressing animals had smaller intracellular inclusions than ATZ yet appeared to have a greater negative effect on animal fitness. Surprisingly, the null mutants, although efficiently degraded, showed a relatively mild gain-of-function proteotoxic phenotype. However, since null variant proteins are degraded differently and do not appear to accumulate, their mechanism of proteotoxicity is likely to be different to that of polymerizing, deficient mutants. Taken together, these studies showed that C. elegans is an inexpensive tool to assess the proteotoxicity of different AT variants using a transgenic approach.
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Affiliation(s)
- Erin E. Cummings
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - Linda P. O’Reilly
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - Dale E. King
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - Richard M. Silverman
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - Mark T. Miedel
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - Cliff J. Luke
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
| | - David H. Perlmutter
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
- Department of Cell Biology and Molecular Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Gary A. Silverman
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
- Department of Cell Biology and Molecular Physiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (SCP); (GAS)
| | - Stephen C. Pak
- Department of Pediatrics, University of Pittsburgh School of Medicine, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (SCP); (GAS)
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27
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Teckman JH, Mangalat N. Alpha-1 antitrypsin and liver disease: mechanisms of injury and novel interventions. Expert Rev Gastroenterol Hepatol 2015; 9:261-8. [PMID: 25066184 DOI: 10.1586/17474124.2014.943187] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
α-1-Antitrypsin (α1AT) is a serum glycoprotein synthesized in the liver. The majority of patients with α1AT deficiency liver disease are homozygous for the Z mutant of α1AT (called ZZ or 'PIZZ'). This mutant gene directs the synthesis of an abnormal protein which folds improperly during biogenesis. Most of these mutant Z protein molecules undergo proteolysis; however, some of the mutant protein accumulates in hepatocytes. Hepatocytes with the largest mutant protein burdens undergo apoptosis, causing compensatory hepatic proliferation. Cycles of hepatocyte injury, cell death and compensatory proliferation results in liver disease ranging from mild asymptomatic enzyme elevations to hepatic fibrosis, cirrhosis and hepatocellular carcinoma. There is a high variability in clinical disease presentation suggesting that environmental and genetic modifiers are important. Management of α1AT liver disease is based on standard supportive care and liver transplant. However, increased understanding of the cellular mechanisms of liver injury has led to new clinical trials.
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Affiliation(s)
- Jeffrey H Teckman
- St. Louis University School of Medicine, Cardinal Glennon Children's Medical Center, 1465 South Grand Blvd, St. Louis, MO 63104, USA
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28
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McElvaney OJ, Bella AME, McElvaney NG. α-1 antitrypsin deficiency: current and future treatment options. Expert Opin Orphan Drugs 2014. [DOI: 10.1517/21678707.2015.997208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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29
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Duvoix A, Roussel B, Lomas D. Molecular pathogenesis of alpha-1-antitrypsin deficiency. Rev Mal Respir 2014; 31:992-1002. [DOI: 10.1016/j.rmr.2014.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 03/14/2014] [Indexed: 11/24/2022]
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30
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Weiss A, Joerss H, Brockmeyer J. Structural and functional characterization of cleavage and inactivation of human serine protease inhibitors by the bacterial SPATE protease EspPα from enterohemorrhagic E. coli. PLoS One 2014; 9:e111363. [PMID: 25347319 PMCID: PMC4210187 DOI: 10.1371/journal.pone.0111363] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 10/01/2014] [Indexed: 11/19/2022] Open
Abstract
EspPα and EspI are serine protease autotransporters found in enterohemorrhagic Escherichia coli. They both belong to the SPATE autotransporter family and are believed to contribute to pathogenicity via proteolytic cleavage and inactivation of different key host proteins during infection. Here, we describe the specific cleavage and functional inactivation of serine protease inhibitors (serpins) by EspPα and compare this activity with the related SPATE EspI. Serpins are structurally related proteins that regulate vital protease cascades, such as blood coagulation and inflammatory host response. For the rapid determination of serpin cleavage sites, we applied direct MALDI-TOF-MS or ESI-FTMS analysis of coincubations of serpins and SPATE proteases and confirmed observed cleavage positions using in-gel-digest of SDS-PAGE-separated degradation products. Activities of both serpin and SPATE protease were assessed in a newly developed photometrical assay using chromogenic peptide substrates. EspPα cleaved the serpins α1-protease inhibitor (α1-PI), α1-antichymotrypsin, angiotensinogen, and α2-antiplasmin. Serpin cleavage led to loss of inhibitory function as demonstrated for α1-PI while EspPα activity was not affected. Notably, EspPα showed pronounced specificity and cleaved procoagulatory serpins such as α2-antiplasmin while the anticoagulatory antithrombin III was not affected. Together with recently published research, this underlines the interference of EspPα with hemostasis or inflammatory responses during infection, while the observed interaction of EspI with serpins is likely to be not physiologically relevant. EspPα-mediated serpin cleavage occurred always in flexible loops, indicating that this structural motif might be required for substrate recognition.
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Affiliation(s)
- André Weiss
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Hanna Joerss
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Jens Brockmeyer
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
- * E-mail:
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31
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Abstract
Alpha-1-antitrypsin (a1AT) deficiency is a common, but under-diagnosed, genetic disease. In the classical form, patients are homozygous for the Z mutant of the a1AT gene (called ZZ or PIZZ), which occurs in 1 in 2,000-3,500 births. The mutant Z gene directs the synthesis of large quantities of the mutant Z protein in the liver, which folds abnormally during biogenesis and accumulates intracellularly, rather than being efficiently secreted. The accumulation mutant Z protein within hepatocytes causes liver injury, cirrhosis, and hepatocellular carcinoma via a cascade of chronic hepatocellular apoptosis, regeneration, and end organ injury. There is no specific treatment for a1AT-associated liver disease, other than standard supportive care and transplantation. There is high variability in the clinical manifestations among ZZ homozygous patients, suggesting a strong influence of genetic and environmental modifiers. New insights into the biological mechanisms of intracellular injury have led to new, rational therapeutic approaches.
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Affiliation(s)
- Jeffrey H Teckman
- St. Louis University School of Medicine, Cardinal Glennon Children's Medical Center, 1465 South Grand Blvd., St. Louis, MO, 63104, USA,
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32
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Gooptu B, Dickens JA, Lomas DA. The molecular and cellular pathology of α₁-antitrypsin deficiency. Trends Mol Med 2013; 20:116-27. [PMID: 24374162 DOI: 10.1016/j.molmed.2013.10.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/28/2013] [Accepted: 10/31/2013] [Indexed: 12/30/2022]
Abstract
Since its discovery 50 years ago, α₁-antitrypsin deficiency has represented a case study in molecular medicine, with careful clinical characterisation guiding genetic, biochemical, biophysical, structural, cellular, and in vivo studies. Here we highlight the milestones in understanding the disease mechanisms and show how they have spurred the development of novel therapeutic strategies. α₁-Antitrypsin deficiency is an archetypal conformational disease. Its pathogenesis demonstrates the interplay between protein folding and quality control mechanisms, with aberrant conformational changes causing liver and lung disease through combined loss- and toxic gain-of-function effects. Moreover, α₁-antitrypsin exemplifies the ability of diverse proteins to self-associate into a range of morphologically distinct polymers, suggesting a mechanism for protein and cell evolution.
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Affiliation(s)
- Bibek Gooptu
- Division of Asthma, Allergy, and Lung Biology, King's College London, 5th Floor, Tower Wing, Guy's Hospital, London, SE1 9RT, UK; Institute of Structural and Molecular Biology/Crystallography, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK
| | - Jennifer A Dickens
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Cambridge, CB2 0XY, UK
| | - David A Lomas
- Institute of Structural and Molecular Biology/Crystallography, Department of Biological Sciences, Birkbeck College, University of London, Malet Street, London, WC1E 7HX, UK; Division of Medicine, University College London, 1st Floor, Maple House, 149, Tottenham Court Road, London, W1T 7NF, UK.
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33
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Ordóñez A, Snapp EL, Tan L, Miranda E, Marciniak SJ, Lomas DA. Endoplasmic reticulum polymers impair luminal protein mobility and sensitize to cellular stress in alpha1-antitrypsin deficiency. Hepatology 2013; 57:10.1002/hep.26173. [PMID: 23197448 PMCID: PMC3871212 DOI: 10.1002/hep.26173] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Point mutants of alpha1 -antitrypsin (α1AT) form ordered polymers that are retained as inclusions within the endoplasmic reticulum (ER) of hepatocytes in association with neonatal hepatitis, cirrhosis, and hepatocellular carcinoma. These inclusions cause cell damage and predispose to ER stress in the absence of the classical unfolded protein response (UPR). The pathophysiology underlying this ER stress was explored by generating cell models that conditionally express wild-type (WT) α1AT, two mutants that cause polymer-mediated inclusions and liver disease (E342K [the Z allele] and H334D) and a truncated mutant (Null Hong Kong; NHK) that induces classical ER stress and is removed by ER-associated degradation. Expression of the polymeric mutants resulted in gross changes in the ER luminal environment that recapitulated the changes observed in liver sections from individuals with PI*ZZ α1AT deficiency. In contrast, expression of NHK α1AT caused electron lucent dilatation and expansion of the ER throughout the cell. Photobleaching microscopy in live cells demonstrated a decrease in the mobility of soluble luminal proteins in cells that express E342K and H334D α1AT, when compared to those that express WT and NHK α1AT (0.34 ± 0.05, 0.22 ± 0.03, 2.83 ± 0.30, and 2.84 ± 0.55 μm(2) /s, respectively). There was no effect on protein mobility within ER membranes, indicating that cisternal connectivity was not disrupted. Polymer expression alone was insufficient to induce the UPR, but the resulting protein overload rendered cells hypersensitive to ER stress induced by either tunicamycin or glucose depletion. CONCLUSION Changes in protein diffusion provide an explanation for the cellular consequences of ER protein overload in mutants that cause inclusion body formation and α1AT deficiency.
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Affiliation(s)
- Adriana Ordóñez
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Erik L Snapp
- Department Anatomy and Structural Biology, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA
| | - Lu Tan
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Elena Miranda
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK,Dipartimento di Biologia e Biotecnologie ‘Charles Darwin’ e Istituto Pasteur – Fondazione Cenci Bolognetti, Università di Roma “La Sapienza”, p.le Aldo Moro 5, 00185 Rome, Italy
| | - Stefan J Marciniak
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - David A Lomas
- Department of Medicine, University of Cambridge, Cambridge Institute for Medical Research, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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34
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Lomas DA. Twenty Years of Polymers: A Personal Perspective on Alpha-1 Antitrypsin Deficiency. COPD 2013; 10 Suppl 1:17-25. [DOI: 10.3109/15412555.2013.764401] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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35
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Teckman JH. Liver Disease in Alpha-1 Antitrypsin Deficiency: Current Understanding and Future Therapy. COPD 2013; 10 Suppl 1:35-43. [DOI: 10.3109/15412555.2013.765839] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abstract
Although much remains to be done, recent advances and the advent of new methodologies are promising and should yield increased understanding of the genetic and epigenetic mechanisms influencing the pathogenesis of COPD, both related and unrelated to severe AAT deficiency. Such understanding should ultimately be translated into novel approaches to prevent, diagnose, and treat COPD.
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Affiliation(s)
- Marilyn Foreman
- Division of Pulmonary and Critical Care Medicine, Dept. of Medicine, Morehouse School of Medicine
| | - Michael Campos
- Division of Pulmonary, Critical Care and Sleep Medicine, Dept. of Medicine, University of Miami Miller School of Medicine
| | - Juan C. Celedón
- Division of Pediatric Pulmonary Medicine, Allergy and Immunology, Dept. of Pediatrics, Children’s Hospital of Pittsburgh of UPMC
- Division of Pulmonary, Allergy and Critical Care Medicine, Dept. of Medicine, University of Pittsburgh School of Medicine
- Corresponding author: Juan C. Celedón, M.D., Dr.P.H., F.A.C.P., F.C.C.P., Division of Pediatric Pulmonary Medicine, Allergy and Immunology, Children’s Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Pittsburgh, PA 15224, Phone: 412.692.8429; Fax: 412.692.7636,
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Fra AM, Gooptu B, Ferrarotti I, Miranda E, Scabini R, Ronzoni R, Benini F, Corda L, Medicina D, Luisetti M, Schiaffonati L. Three new alpha1-antitrypsin deficiency variants help to define a C-terminal region regulating conformational change and polymerization. PLoS One 2012; 7:e38405. [PMID: 22723858 PMCID: PMC3377647 DOI: 10.1371/journal.pone.0038405] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 05/05/2012] [Indexed: 11/19/2022] Open
Abstract
Alpha1-antitrypsin (AAT) deficiency is a hereditary disorder associated with reduced AAT plasma levels, predisposing adults to pulmonary emphysema. The most common genetic AAT variants found in patients are the mildly deficient S and the severely deficient Z alleles, but several other pathogenic rare alleles have been reported. While the plasma AAT deficiency is a common trait of the disease, only a few AAT variants, including the prototypic Z AAT and some rare variants, form cytotoxic polymers in the endoplasmic reticulum of hepatocytes and predispose to liver disease. Here we report the identification of three new rare AAT variants associated to reduced plasma levels and characterize their molecular behaviour in cellular models. The variants, called Mpisa (Lys259Ile), Etaurisano (Lys368Glu) and Yorzinuovi (Pro391His), showed reduced secretion compared to control M AAT, and accumulated to different extents in the cells as ordered polymeric structures resembling those formed by the Z variant. Structural analysis of the mutations showed that they may facilitate polymerization both by loosening ‘latch’ interactions constraining the AAT reactive loop and through effects on core packing. In conclusion, the new AAT deficiency variants, besides increasing the risk of lung disease, may predispose to liver disease, particularly if associated with the common Z variant. The new mutations cluster structurally, thus defining a region of the AAT molecule critical for regulating its conformational state.
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Affiliation(s)
- Anna M Fra
- Department of Biomedical Sciences and Biotechnology, University of Brescia, Brescia, Italy.
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38
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Blanchet X, Péré-Brissaud A, Duprat N, Pinault E, Delourme D, Ouali A, Combet C, Maftah A, Pélissier P, Brémaud L. Mutagenesis of the bovSERPINA3-3 demonstrates the requirement of aspartate-371 for intermolecular interaction and formation of dimers. Protein Sci 2012; 21:977-86. [PMID: 22505318 DOI: 10.1002/pro.2078] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 03/30/2012] [Accepted: 04/02/2012] [Indexed: 11/10/2022]
Abstract
The family of serpins is known to fold into a metastable state that is required for the proteinase inhibition mechanism. One of the consequences of this conformational flexibility is the tendency of some mutated serpins to form polymers, which occur through the insertion of the reactive center loop of one serpin molecule into the A-sheet of another. This "A-sheet polymerization" has remained an attractive explanation for the molecular mechanism of serpinopathies. Polymerization of serpins can also take place in vitro under certain conditions (e.g., pH or temperature). Surprisingly, on sodium dodecyl sulfate/polyacrylamide gel electrophoresis, bovSERPINA3-3 extracted from skeletal muscle or expressed in Escherichia coli was mainly observed as a homodimer. Here, in this report, by site-directed mutagenesis of recombinant bovSERPINA3-3, with substitution D371A, we demonstrate the importance of D371 for the intermolecular linkage observed in denaturing and reducing conditions. This residue influences the electrophoretic and conformational properties of bovSERPINA3-3. By structural modeling of mature bovSERPINA3-3, we propose a new "non-A-sheet swap" model of serpin homodimer in which D371 is involved at the molecular interface.
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Affiliation(s)
- X Blanchet
- Faculté des Sciences et Techniques, INRA, UMR1061 Unité de génétique Moléculaire Animale, Université de Limoges, FR 3503 GEIST, 87060 Limoges, France
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39
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Tsutsui Y, Sarkar A, Wintrode PL. Probing serpin conformational change using mass spectrometry and related methods. Methods Enzymol 2012; 501:325-50. [PMID: 22078541 DOI: 10.1016/b978-0-12-385950-1.00015-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The folding, misfolding, and inhibitory mechanisms of serpins are linked to both thermodynamic metastability and conformational flexibility. Characterizing the structural distribution of stability and flexibility in serpins in solution is challenging due to their large size and propensity for aggregation. Structural mass spectrometry techniques offer powerful tools for probing the mechanisms of serpin function and disfunction. In this chapter, we review the principles of the two most commonly employed structural mass spectrometry techniques--hydrogen/deuterium exchange and chemical footprinting--and describe their application to studying serpin flexibility, stability, and conformational change in solution. We also review the application of both hydrogen/deuterium exchange and ion mobility mass spectrometry to probe the mechanism of serpin polymerization and the structure of serpin polymers.
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Affiliation(s)
- Yuko Tsutsui
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, USA
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40
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Folding mechanism of the metastable serpin α1-antitrypsin. Proc Natl Acad Sci U S A 2012; 109:4467-72. [PMID: 22392975 DOI: 10.1073/pnas.1109125109] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The misfolding of serpins is linked to several genetic disorders including emphysema, thrombosis, and dementia. During folding, inhibitory serpins are kinetically trapped in a metastable state in which a stretch of residues near the C terminus of the molecule are exposed to solvent as a flexible loop (the reactive center loop). When they inhibit target proteases, serpins transition to a stable state in which the reactive center loop forms part of a six-stranded β-sheet. Here, we use hydrogen-deuterium exchange mass spectrometry to monitor region-specific folding of the canonical serpin human α(1)-antitrypsin (α(1)-AT). We find large differences in the folding kinetics of different regions. A key region in the metastable → stable transition, β-strand 5A, shows a lag phase of nearly 350 s. In contrast, the "B-C barrel" region shows no lag phase and the incorporation of the C-terminal residues into β-sheets B and C is largely complete before the center of β-sheet A begins to fold. We propose this as the mechanism for trapping α(1)-AT in a metastable form. Additionally, this separation of timescales in the folding of different regions suggests a mechanism by which α(1)-AT avoids polymerization during folding.
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41
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Yamasaki M, Sendall TJ, Pearce MC, Whisstock JC, Huntington JA. Molecular basis of α1-antitrypsin deficiency revealed by the structure of a domain-swapped trimer. EMBO Rep 2011; 12:1011-7. [PMID: 21909074 DOI: 10.1038/embor.2011.171] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 07/20/2011] [Accepted: 07/22/2011] [Indexed: 11/09/2022] Open
Abstract
α(1)-Antitrypsin (α1AT) deficiency is a disease with multiple manifestations, including cirrhosis and emphysema, caused by the accumulation of stable polymers of mutant protein in the endoplasmic reticulum of hepatocytes. However, the molecular basis of misfolding and polymerization remain unknown. We produced and crystallized a trimeric form of α1AT that is recognized by an antibody specific for the pathological polymer. Unexpectedly, this structure reveals a polymeric linkage mediated by domain swapping the carboxy-terminal 34 residues. Disulphide-trapping and antibody-binding studies further demonstrate that runaway C-terminal domain swapping, rather than the s4A/s5A domain swap previously proposed, underlies polymerization of the common Z-mutant of α1AT in vivo.
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Affiliation(s)
- Masayuki Yamasaki
- Department of Haematology, Cambridge Institute for Medical Research, University of Cambridge, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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42
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Roussel BD, Irving JA, Ekeowa UI, Belorgey D, Haq I, Ordóñez A, Kruppa AJ, Duvoix A, Rashid ST, Crowther DC, Marciniak SJ, Lomas DA. Unravelling the twists and turns of the serpinopathies. FEBS J 2011; 278:3859-67. [DOI: 10.1111/j.1742-4658.2011.08201.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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43
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Irving JA, Ekeowa UI, Belorgey D, Haq I, Gooptu B, Miranda E, Pérez J, Roussel BD, Ordóñez A, Dalton LE, Thomas SE, Marciniak SJ, Parfrey H, Chilvers ER, Teckman JH, Alam S, Mahadeva R, Rashid ST, Vallier L, Lomas DA. The serpinopathies studying serpin polymerization in vivo. Methods Enzymol 2011; 501:421-66. [PMID: 22078544 DOI: 10.1016/b978-0-12-385950-1.00018-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The serpinopathies result from point mutations in members of the serine protease inhibitor or serpin superfamily. They are characterized by the formation of ordered polymers that are retained within the cell of synthesis. This causes disease by a "toxic gain of function" from the accumulated protein and a "loss of function" as a result of the deficiency of inhibitors that control important proteolytic cascades. The serpinopathies are exemplified by the Z (Glu342Lys) mutant of α₁-antitrypsin that results in the retention of ordered polymers within the endoplasmic reticulum of hepatocytes. These polymers form the intracellular inclusions that are associated with neonatal hepatitis, cirrhosis, and hepatocellular carcinoma. A second example results from mutations in the neurone-specific serpin-neuroserpin to form ordered polymers that are retained as inclusions within subcortical neurones as Collins' bodies. These inclusions underlie the autosomal dominant dementia familial encephalopathy with neuroserpin inclusion bodies or FENIB. There are different pathways to polymer formation in vitro but not all form polymers that are relevant in vivo. It is therefore essential that protein-based structural studies are interpreted in the context of human samples and cell and animal models of disease. We describe here the biochemical techniques, monoclonal antibodies, cell biology, animal models, and stem cell technology that are useful to characterize the serpin polymers that form in vivo.
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Affiliation(s)
- James A Irving
- Department of Medicine, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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44
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Ricagno S, Pezzullo M, Barbiroli A, Manno M, Levantino M, Santangelo MG, Bonomi F, Bolognesi M. Two latent and two hyperstable polymeric forms of human neuroserpin. Biophys J 2010; 99:3402-11. [PMID: 21081089 PMCID: PMC2980742 DOI: 10.1016/j.bpj.2010.09.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 09/08/2010] [Accepted: 09/09/2010] [Indexed: 02/02/2023] Open
Abstract
Human neuroserpin (hNS) is a serine protease inhibitor that belongs to the serpin superfamily and is expressed in nervous tissues. The serpin fold is generally characterized by a long exposed loop, termed the reactive center loop, that acts as bait for the target protease. Intramolecular insertion of the reactive center loop into the main serpin β-sheet leads to the serpin latent form. As with other known serpins, hNS pathological mutants have been shown to accumulate as polymers composed of quasi-native protein molecules. Although hNS polymerization has been intensely studied, a general agreement about serpin polymer organization is still lacking. Here we report a biophysical characterization of native hNS that is shown to undergo two distinct conformational transitions, at 55°C and 85°C, both leading to distinct latent and polymeric species. The latent and polymer hNS forms obtained at 45°C and 85°C differ in their chemical and thermal stabilities; furthermore, the hNS polymers also differ in size and morphology. Finally, the 85°C polymer shows a higher content of intermolecular β-sheet interactions than the 45°C polymer. Together, these results suggest a more complex conformational scenario than was previously envisioned, and, in a general context, may help reconcile the current contrasting views on serpin polymerization.
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Affiliation(s)
- Stefano Ricagno
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Centro Interdisciplinare Materiali e Interfacce Nanostrutturati, Università di Milano, Milan, Italy
- Dipartimento di Biochimica, Università di Pavia, Pavia, Italy
- Laboratori di Biotecnologie, Istituto Di Ricovero e Cura a Carattere Scientifico Fondazione Policlinico San Matteo, Pavia, Italy
| | - Margherita Pezzullo
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Centro Interdisciplinare Materiali e Interfacce Nanostrutturati, Università di Milano, Milan, Italy
| | - Alberto Barbiroli
- Sezione di Biochimica, Dipartimento di Scienze Molecolari Agroalimentari, Università di Milano, Milan, Italy
| | - Mauro Manno
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, CNR, Palermo, Italy
| | - Matteo Levantino
- Dipartimento di Scienze Fisiche ed Astronomiche, Università of Palermo, Palermo, Italy
| | | | - Francesco Bonomi
- Sezione di Biochimica, Dipartimento di Scienze Molecolari Agroalimentari, Università di Milano, Milan, Italy
| | - Martino Bolognesi
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Centro Interdisciplinare Materiali e Interfacce Nanostrutturati, Università di Milano, Milan, Italy
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45
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Knaupp AS, Levina V, Robertson AL, Pearce MC, Bottomley SP. Kinetic Instability of the Serpin Z α1-Antitrypsin Promotes Aggregation. J Mol Biol 2010; 396:375-83. [PMID: 19944704 DOI: 10.1016/j.jmb.2009.11.048] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 11/18/2009] [Accepted: 11/19/2009] [Indexed: 11/28/2022]
Affiliation(s)
- Anja S Knaupp
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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46
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α1-Antitrypsin deficiency, chronic obstructive pulmonary disease and the serpinopathies. Clin Sci (Lond) 2009; 116:837-50. [DOI: 10.1042/cs20080484] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
α1-Antitrypsin is the prototypical member of the serine proteinase inhibitor or serpin superfamily of proteins. The family includes α1-antichymotrypsin, C1 inhibitor, antithrombin and neuroserpin, which are all linked by a common molecular structure and the same suicidal mechanism for inhibiting their target enzymes. Point mutations result in an aberrant conformational transition and the formation of polymers that are retained within the cell of synthesis. The intracellular accumulation of polymers of mutant α1-antitrypsin and neuroserpin results in a toxic gain-of-function phenotype associated with cirrhosis and dementia respectively. The lack of important inhibitors results in overactivity of proteolytic cascades and diseases such as COPD (chronic obstructive pulmonary disease) (α1-antitrypsin and α1-antichymotrypsin), thrombosis (antithrombin) and angio-oedema (C1 inhibitor). We have grouped these conditions that share the same underlying disease mechanism together as the serpinopathies. In the present review, the molecular and pathophysiological basis of α1-antitrypsin deficiency and other serpinopathies are considered, and we show how understanding this unusual mechanism of disease has resulted in the development of novel therapeutic strategies.
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47
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Tsutsui Y, Kuri B, Sengupta T, Wintrode PL. The structural basis of serpin polymerization studied by hydrogen/deuterium exchange and mass spectrometry. J Biol Chem 2008; 283:30804-11. [PMID: 18794298 DOI: 10.1074/jbc.m804048200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serpinopathies are a group of inherited disorders that share as their molecular basis the misfolding and polymerization of serpins, an important class of protease inhibitors. Depending on the identity of the serpin, conditions arising from polymerization include emphysema, thrombosis, and dementia. The structure of serpin polymers is thus of considerable medical interest. Wild-type alpha(1)-antitrypsin will form polymers upon incubation at moderate temperatures and has been widely used as a model system for studying serpin polymerization. Using hydrogen/deuterium exchange and mass spectrometry, we have obtained molecular level structural information on the alpha(1)-antitrypsin polymer. We found that the flexible reactive center loop becomes strongly protected upon polymerization. We also found significant increases in protection in the center of beta-sheet A and in helix F. These results support a model in which linkage between serpins is achieved through insertion of the reactive center loop of one serpin into beta-sheet A of another. We have also examined the heat-induced conformational changes preceding polymerization. We found that polymerization is preceded by significant destabilization of beta-sheet C. On the basis of our results, we propose a mechanism for polymerization in which beta-strand 1C is displaced from the rest of beta-sheet C through a binary serpin/serpin interaction. Displacement of strand 1C triggers further conformational changes, including the opening of beta-sheet A, and allows for subsequent polymerization.
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Affiliation(s)
- Yuko Tsutsui
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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48
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Gooptu B, Lomas DA. Polymers and inflammation: disease mechanisms of the serpinopathies. ACTA ACUST UNITED AC 2008; 205:1529-34. [PMID: 18591408 PMCID: PMC2442629 DOI: 10.1084/jem.20072080] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Members of the serpin (serine proteinase inhibitor) superfamily play a central role in the control of inflammatory, coagulation, and fibrinolytic cascades. Point mutations that cause abnormal conformational transitions in these proteins can trigger disease. Recent work has defined three pathways by which these conformers cause tissue damage. Here, we describe how these three mechanisms can be integrated into a new model of the pathogenesis of emphysema caused by mutations in the serpin α1-antitrypsin.
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Affiliation(s)
- Bibek Gooptu
- School of Crystallography, Birkbeck College, University of London, London WC1E 7HX, England, UK
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49
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Zhang Q, Law RHP, Bottomley SP, Whisstock JC, Buckle AM. A structural basis for loop C-sheet polymerization in serpins. J Mol Biol 2008; 376:1348-59. [PMID: 18234218 DOI: 10.1016/j.jmb.2007.12.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 12/17/2007] [Accepted: 12/20/2007] [Indexed: 10/22/2022]
Abstract
In this study, we report the X-ray crystal structure of an N-terminally truncated variant of the bacterial serpin, tengpin (tengpinDelta42). Our data reveal that tengpinDelta42 adopts a variation of the latent conformation in which the reactive center loop is hyperinserted into the A beta-sheet and removed from the vicinity of the C-sheet. This conformational change leaves the C beta-sheet completely exposed and permits antiparallel edge-strand interactions between the exposed portion of the reactive center loop of one molecule and strand s2C of the C beta-sheet of the neighboring molecule in the crystal lattice. Our structural data thus reveal that tengpinDelta42 forms a loop C-sheet polymer in the crystal lattice. In vivo serpins have a propensity to misfold and form long-chain polymers, a process that underlies serpinopathies such as emphysema, thrombosis and dementia. Native serpins are thought to polymerize via a loop A-sheet mechanism. However, studies on plasminogen activator inhibitor 1 and the S49P variant of human neuroserpin reveal that the latent form of these molecules can also polymerize. Polymerization of latent neuroserpin may be important for the development of familial encephalopathy with neuroserpin inclusion bodies. Our structural data provide a possible mechanism for polymerization by latent serpins.
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Affiliation(s)
- Qingwei Zhang
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Melbourne, VIC 3800, Australia
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50
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Na YR, Im H. Specific interactions of serpins in their native forms attenuate their conformational transitions. Protein Sci 2007; 16:1659-66. [PMID: 17600149 PMCID: PMC2203359 DOI: 10.1110/ps.072838107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Plasminogen activator inhibitor-1 (PAI-1) belongs to the serine protease inhibitor (serpin) protein superfamily. Serpins are unique in that their native forms are not the most thermodynamically stable conformation; instead, a more stable, latent conformation exists. During the transition to the latent form, the first strand of beta-sheet C (s1C) in the serpin is peeled away from the beta-sheet, and the reactive center loop (RCL) is inserted into beta-sheet A, rendering the serpin inactive. To elucidate the contribution of specific interactions in the metastable native form to the latency transition, we examined the effect of mutations at the s1C of PAI-1, specifically in positions P4' through P10'. Several mutations strengthened the interactions between these residues and the core protein, and slowed the transition of the protein from the metastable native form to the latent form. In particular, anchoring of the strand to the protein's hydrophobic core at the beginning (P4' site) and center of the strand (P8' site) greatly retarded the latency transition. Mutations that weakened the interactions at the s1C region facilitated the conformational conversion of the protein to the latent form. PAI-1's overall structural stability was largely unchanged by the mutations, as evaluated by urea-induced equilibrium unfolding monitored via fluorescence emission. Therefore, the mutations likely exerted their effects by modulating the height of the energy barrier from the native to the latent form. Our results show that interactions found only in the metastable native form of serpins are important structural features that attenuate folding of the proteins into their latent forms.
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Affiliation(s)
- Yu-Ran Na
- Department of Molecular Biology, Sejong University, Kwangjin-gu, Seoul 143-747, Korea
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