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Kent D, Ng SS, Syanda AM, Khoshkenar P, Ronzoni R, Li CZ, Zieger M, Greer C, Hatch S, Segal J, Blackford SJI, Im YR, Chowdary V, Ismaili T, Danovi D, Lewis PA, Irving JA, Sahdeo S, Lomas DA, Ebner D, Mueller C, Rashid ST. Reduction of Z alpha-1 antitrypsin polymers in human iPSC-hepatocytes and mice by LRRK2 inhibitors. Hepatology 2024:01515467-990000000-00945. [PMID: 38954820 DOI: 10.1097/hep.0000000000000969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 04/29/2024] [Indexed: 07/04/2024]
Abstract
BACKGROUND Alpha-1 antitrypsin deficiency (A1ATD) is a life-threatening condition caused by the inheritance of the serpin family A member 1 "Z" genetic variant driving alpha-1 antitrypsin (AAT) protein misfolding in hepatocytes. There are no approved medicines for this disease. METHODS We conducted a high-throughput image-based small molecule screen using patient-derived induced pluripotent stem cell-hepatocytes (iPSC-hepatocytes). Identified targets were validated in vitro using 3 independent patient iPSC lines. The effects of the identified target, leucine-rich repeat kinase 2 (LRRK2), were further evaluated in an animal model of A1ATD through histology and immunohistochemistry and in an autophagy-reporter line. Autophagy induction was assessed through immunoblot and immunofluorescence analyses. RESULTS Small-molecule screen performed in iPSC-hepatocytes identified LRRK2 as a potentially new therapeutic target. Of the commercially available LRRK2 inhibitors tested, we identified CZC-25146, a candidate with favorable pharmacokinetic properties, as capable of reducing polymer load, increasing normal AAT secretion, and reducing inflammatory cytokines in both cells and PiZ mice. Mechanistically, this effect was achieved through the induction of autophagy. CONCLUSIONS Our findings support the use of CZC-25146 and leucine-rich repeat kinase-2 inhibitors in hepatic proteinopathy research and their further investigation as novel therapeutic candidates for A1ATD.
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Affiliation(s)
- Deniz Kent
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, UK
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - Soon Seng Ng
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Adam M Syanda
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Payam Khoshkenar
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - Riccardo Ronzoni
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, UK
| | - Chao Zheng Li
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, UK
| | - Marina Zieger
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - Cindy Greer
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - Stephanie Hatch
- National Phenotypic Screening Centre, University of Oxford, Headington, Oxford, UK
| | - Joe Segal
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, UK
| | - Samuel J I Blackford
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Yu Ri Im
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Vivek Chowdary
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - Taylor Ismaili
- Discovery Sciences, Janssen Research and Development, San Diego, California, USA
| | - Davide Danovi
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, UK
| | | | - James A Irving
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, UK
| | - Sunil Sahdeo
- Discovery Sciences, Janssen Research and Development, San Diego, California, USA
| | - David A Lomas
- UCL Respiratory and the Institute of Structural and Molecular Biology, University College London, London, UK
| | - Daniel Ebner
- National Phenotypic Screening Centre, University of Oxford, Headington, Oxford, UK
| | - Christian Mueller
- Gene Therapy Center, University of Massachusetts, Worchester, Massachusetts, USA
| | - S Tamir Rashid
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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2
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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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3
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Zhao P, Wang C, Sun S, Wang X, Balch WE. Tracing genetic diversity captures the molecular basis of misfolding disease. Nat Commun 2024; 15:3333. [PMID: 38637533 PMCID: PMC11026414 DOI: 10.1038/s41467-024-47520-0] [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: 04/04/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Genetic variation in human populations can result in the misfolding and aggregation of proteins, giving rise to systemic and neurodegenerative diseases that require management by proteostasis. Here, we define the role of GRP94, the endoplasmic reticulum Hsp90 chaperone paralog, in managing alpha-1-antitrypsin deficiency on a residue-by-residue basis using Gaussian process regression-based machine learning to profile the spatial covariance relationships that dictate protein folding arising from sequence variants in the population. Covariance analysis suggests a role for the ATPase activity of GRP94 in controlling the N- to C-terminal cooperative folding of alpha-1-antitrypsin responsible for the correction of liver aggregation and lung-disease phenotypes of alpha-1-antitrypsin deficiency. Gaussian process-based spatial covariance profiling provides a standard model built on covariant principles to evaluate the role of proteostasis components in guiding information flow from genome to proteome in response to genetic variation, potentially allowing us to intervene in the onset and progression of complex multi-system human diseases.
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Affiliation(s)
- Pei Zhao
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China.
| | - Shuhong Sun
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Department of Nutrition and Food Hygiene, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Institute for Brain Tumors, Collaborative Innovation Center for Cancer Personalized Medicine, and Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Xi Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
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4
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Ottaviani S, Bartoli G, Carroll TP, Gangemi F, Balderacchi AM, Barzon V, Corino A, Piloni D, McElvaney NG, Corsico AG, Irving JA, Fra A, Ferrarotti I. Comprehensive Clinical Diagnostic Pipelines Reveal New Variants in Alpha-1 Antitrypsin Deficiency. Am J Respir Cell Mol Biol 2023; 69:355-366. [PMID: 37071847 DOI: 10.1165/rcmb.2022-0470oc] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 04/18/2023] [Indexed: 04/20/2023] Open
Abstract
Alpha-1 antitrypsin deficiency (AATD) is an underdiagnosed disorder associated with mutations in the SERPINA1 gene encoding alpha-1 antitrypsin (AAT). Severe AATD can manifest as pulmonary emphysema and progressive liver disease. Besides the most common pathogenic variants S (E264V) and Z (E342K), many rarer genetic variants of AAT have been found in patients and in the general population. Here we report a panel of new SERPINA1 variants, including 4 null and 16 missense alleles, identified among a cohort of individuals with suspected AATD whose phenotypic follow-up showed inconclusive or atypical results. Because the pathogenic significance of the missense variants was unclear purely on the basis of clinical data, the integration of computational, biochemical, and cellular studies was used to define the associated risk of disease. Established pathogenicity predictors and structural analysis identified a panel of candidate damaging mutations that were characterized by expression in mammalian cell models. Polymer formation, intracellular accumulation, and secretory efficiency were evaluated experimentally. Our results identified two AAT mutants with a Z-like polymerogenic severe deficiency profile (Smilano and Mcampolongo) and three milder variants (Xsarezzo, Pdublin, and Ctiberias). Overall, the experimentally determined behavior of the variants was in agreement with the pathogenicity scores of the REVEL (an ensemble method for predicting the pathogenicity of rare missense variants) predictor, supporting the utility of this bioinformatic tool in the initial assessment of newly identified amino acid substitutions of AAT. Our study, in addition to describing 20 new SERPINA1 variants, provides a model for a multidisciplinary approach to classification of rare AAT variants and their clinical impact on individuals with rare AATD genotypes.
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Affiliation(s)
- Stefania Ottaviani
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
| | - Giulia Bartoli
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Tomás P Carroll
- α-1 Foundation Ireland, Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland
| | - Fabrizio Gangemi
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Alice M Balderacchi
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
| | - Valentina Barzon
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, University of Pavia, Pavia, Italy
| | - Alessandra Corino
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
| | - Davide Piloni
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
| | - Noel G McElvaney
- α-1 Foundation Ireland, Irish Centre for Genetic Lung Disease, Royal College of Surgeons in Ireland Education and Research Centre, Beaumont Hospital, Dublin, Ireland
| | - Angelo G Corsico
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, University of Pavia, Pavia, Italy
- European Reference Network on Rare Respiratory Diseases (ERN-LUNG); and
| | - James A Irving
- University College London Respiratory, Rayne Institute and the Institute of Structural and Molecular Biology, University College London, London, United Kingdom
| | - Annamaria Fra
- Experimental Oncology and Immunology, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Ilaria Ferrarotti
- Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Unità Operativa Complessa Pneumologia, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Policlinico San Matteo, Pavia, Italy
- Department of Internal Medicine and Therapeutics, Pulmonology Unit, University of Pavia, Pavia, Italy
- European Reference Network on Rare Respiratory Diseases (ERN-LUNG); and
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5
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Calamaio S, Serzanti M, Boniotti J, Fra A, Garrafa E, Cominelli M, Verardi R, Poliani PL, Dotti S, Villa R, Mazzoleni G, Dell’Era P, Steimberg N. Human iPSC-Derived 3D Hepatic Organoids in a Miniaturized Dynamic Culture System. Biomedicines 2023; 11:2114. [PMID: 37626611 PMCID: PMC10452373 DOI: 10.3390/biomedicines11082114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/19/2023] [Accepted: 07/25/2023] [Indexed: 08/27/2023] Open
Abstract
The process of identifying and approving a new drug is a time-consuming and expensive procedure. One of the biggest issues to overcome is the risk of hepatotoxicity, which is one of the main reasons for drug withdrawal from the market. While animal models are the gold standard in preclinical drug testing, the translation of results into therapeutic intervention is often ambiguous due to interspecies differences in hepatic metabolism. The discovery of human induced pluripotent stem cells (hiPSCs) and their derivatives has opened new possibilities for drug testing. We used mesenchymal stem cells and hepatocytes both derived from hiPSCs, together with endothelial cells, to miniaturize the process of generating hepatic organoids. These organoids were then cultivated in vitro using both static and dynamic cultures. Additionally, we tested spheroids solely composed by induced hepatocytes. By miniaturizing the system, we demonstrated the possibility of maintaining the organoids, but not the spheroids, in culture for up to 1 week. This timeframe may be sufficient to carry out a hypothetical pharmacological test or screening. In conclusion, we propose that the hiPSC-derived liver organoid model could complement or, in the near future, replace the pharmacological and toxicological tests conducted on animals.
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Affiliation(s)
- Serena Calamaio
- Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; (S.C.); (M.S.)
| | - Marialaura Serzanti
- Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; (S.C.); (M.S.)
| | - Jennifer Boniotti
- Laboratory of Tissue Engineering, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy; (J.B.); (G.M.)
| | - Annamaria Fra
- Oncology and Experimental Immunology Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy;
| | - Emirena Garrafa
- Laboratory Diagnostics, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy;
| | - Manuela Cominelli
- Pathology Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; (M.C.); (P.L.P.)
| | - Rosanna Verardi
- Laboratory for Stem Cell Manipulation and Cryopreservation, Department of Transfusion Medicine, ASST Spedali Civili di Brescia, 25123 Brescia, Italy;
| | - Pietro Luigi Poliani
- Pathology Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; (M.C.); (P.L.P.)
| | - Silvia Dotti
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, 25124 Brescia, Italy; (S.D.); (R.V.)
| | - Riccardo Villa
- Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna, 25124 Brescia, Italy; (S.D.); (R.V.)
| | - Giovanna Mazzoleni
- Laboratory of Tissue Engineering, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy; (J.B.); (G.M.)
| | - Patrizia Dell’Era
- Cellular Fate Reprogramming Unit, Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy; (S.C.); (M.S.)
| | - Nathalie Steimberg
- Laboratory of Tissue Engineering, Department of Clinical and Experimental Sciences, University of Brescia, 25123 Brescia, Italy; (J.B.); (G.M.)
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6
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Sun S, Wang C, Zhao P, Kline GM, Grandjean JMD, Jiang X, Labaudiniere R, Wiseman RL, Kelly JW, Balch WE. Capturing the conversion of the pathogenic alpha-1-antitrypsin fold by ATF6 enhanced proteostasis. Cell Chem Biol 2023; 30:22-42.e5. [PMID: 36630963 PMCID: PMC9930901 DOI: 10.1016/j.chembiol.2022.12.004] [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: 08/30/2022] [Revised: 11/07/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
Genetic variation in alpha-1 antitrypsin (AAT) causes AAT deficiency (AATD) through liver aggregation-associated gain-of-toxic pathology and/or insufficient AAT activity in the lung manifesting as chronic obstructive pulmonary disease (COPD). Here, we utilize 71 AATD-associated variants as input through Gaussian process (GP)-based machine learning to study the correction of AAT folding and function at a residue-by-residue level by pharmacological activation of the ATF6 arm of the unfolded protein response (UPR). We show that ATF6 activators increase AAT neutrophil elastase (NE) inhibitory activity, while reducing polymer accumulation for the majority of AATD variants, including the prominent Z variant. GP-based profiling of the residue-by-residue response to ATF6 activators captures an unexpected role of the "gate" area in managing AAT-specific activity. Our work establishes a new spatial covariant (SCV) understanding of the convertible state of the protein fold in response to genetic perturbation and active environmental management by proteostasis enhancement for precision medicine.
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Affiliation(s)
- Shuhong Sun
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Chao Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Pei Zhao
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Gabe M Kline
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | | | - Xin Jiang
- Protego Biopharma, 10945 Vista Sorrento Parkway, San Diego, CA, USA
| | | | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jeffery W Kelly
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - William E Balch
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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7
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Callea F, Tomà P, Bellacchio E. The Recruitment-Secretory Block ("R-SB") Phenomenon and Endoplasmic Reticulum Storage Diseases. Int J Mol Sci 2021; 22:ijms22136807. [PMID: 34202771 PMCID: PMC8269287 DOI: 10.3390/ijms22136807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2021] [Accepted: 06/19/2021] [Indexed: 01/28/2023] Open
Abstract
In this article, we review the biological and clinical implication of the Recruitment-Secretory Block (“R-SB”) phenomenon. The phenomenon refers to the reaction of the liver with regard to protein secretion in conditions of clinical stimulation. Our basic knowledge of the process is due to the experimental work in animal models. Under basal conditions, the protein synthesis is mainly carried out by periportal (zone 1) hepatocytes that are considered the “professional” synthesizing protein cells. Under stimulation, midlobular and centrolobular (zones 2 and 3) hepatocytes, are progressively recruited according to lobular gradients and contribute to the increase of synthesis and secretion. The block of secretion, operated by exogenous agents, causes intracellular retention of all secretory proteins. The Pi MZ phenotype of Alpha-1-antitrypsin deficiency (AATD) has turned out to be the key for in vivo studies of the reaction of the liver, as synthesis and block of secretion are concomitant. Indeed, the M fraction of AAT is stimulated for synthesis and regularly exported while the Z fraction is mostly retained within the cell. For that reason, the phenomenon has been designated “Recruitment-Secretory Block” (“R-SB”). The “R-SB” phenomenon explains why: (a) the MZ individuals can correct the serum deficiency; (b) the resulting immonohistochemical and electron microscopic (EM) patterns are very peculiar and specific for the diagnosis of the Z mutation in tissue sections in the absence of genotyping; (c) the term carrier is no longer applicable for the heterozygous condition as all Pi MZ individuals undergo storage and the storage predisposes to liver damage. The storage represents the true elementary lesion and consequently reflects the phenotype-genotype correlation; (d) the site and function of the extrahepatic AAT and the relationship between intra and extracellular AAT; (e) last but not least, the concept of Endoplasmic Reticulum Storage Disease (ERSD) and of a new disease, hereditary hypofibrinogenemia with hepatic storage (HHHS). In the light of the emerging phenomenon, described in vitro, namely that M and Z AAT can form heteropolymers within hepatocytes as well as in circulation, we have reviewed the whole clinical and experimental material collected during forty years, in order to evaluate to what extent the polymerization phenomenon occurs in vivo. The paper summarizes similarities and differences between AAT and Fibrinogen as well as between the related diseases, AATD and HHHS. Indeed, fibrinogen gamma chain mutations undergo an aggregation process within the RER of hepatocytes similar to AATD. In addition, this work has clarified the intriguing phenomenon underlying a new syndrome, hereditary hypofibrinogenemia and hypo-APO-B-lipoproteinemia with hepatic storage of fibrinogen and APO-B lipoproteins. It is hoped that these studies could contribute to future research and select strategies aimed to simultaneously correct the hepatocytic storage, thus preventing the liver damage and the plasma deficiency of the two proteins.
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Affiliation(s)
- Francesco Callea
- Department of Histopathology, Bugando Medical Centre, Catholic University of Healthy and Allied Sciences, Mwanza P.O. Box 1464, Tanzania
- Correspondence: (F.C.); (E.B.); Tel.: +255-7543343938 (F.C.); +39-0668594291 (E.B.)
| | - Paolo Tomà
- Dipartimento Diagnostica Immagini, Bambino Gesù Childrens’ Hospital, IRCCS, Piazza S. Onofrio 4, 00165 Roma, Italy;
| | - Emanuele Bellacchio
- Area di Ricerca Genetica e Malattie Rare Bambino Gesù Children’s Hospital, IRCCS, Piazza S. Onofrio 4, 00165 Roma, Italy
- Correspondence: (F.C.); (E.B.); Tel.: +255-7543343938 (F.C.); +39-0668594291 (E.B.)
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8
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Fregno I, Fasana E, Soldà T, Galli C, Molinari M. N-glycan processing selects ERAD-resistant misfolded proteins for ER-to-lysosome-associated degradation. EMBO J 2021; 40:e107240. [PMID: 34152647 PMCID: PMC8327951 DOI: 10.15252/embj.2020107240] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
Efficient degradation of by‐products of protein biogenesis maintains cellular fitness. Strikingly, the major biosynthetic compartment in eukaryotic cells, the endoplasmic reticulum (ER), lacks degradative machineries. Misfolded proteins in the ER are translocated to the cytosol for proteasomal degradation via ER‐associated degradation (ERAD). Alternatively, they are segregated in ER subdomains that are shed from the biosynthetic compartment and are delivered to endolysosomes under control of ER‐phagy receptors for ER‐to‐lysosome‐associated degradation (ERLAD). Demannosylation of N‐linked oligosaccharides targets terminally misfolded proteins for ERAD. How misfolded proteins are eventually marked for ERLAD is not known. Here, we show for ATZ and mutant Pro‐collagen that cycles of de‐/re‐glucosylation of selected N‐glycans and persistent association with Calnexin (CNX) are required and sufficient to mark ERAD‐resistant misfolded proteins for FAM134B‐driven lysosomal delivery. In summary, we show that mannose and glucose processing of N‐glycans are triggering events that target misfolded proteins in the ER to proteasomal (ERAD) and lysosomal (ERLAD) clearance, respectively, regulating protein quality control in eukaryotic cells.
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Affiliation(s)
- Ilaria Fregno
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Elisa Fasana
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Tatiana Soldà
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Carmela Galli
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland
| | - Maurizio Molinari
- Faculty of Biomedical Sciences, Institute for Research in Biomedicine, Università della Svizzera italiana (USI), Bellinzona, Switzerland.,School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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9
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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: 7] [Impact Index Per Article: 2.3] [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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10
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Lomas DA, Irving JA, Arico‐Muendel C, Belyanskaya S, Brewster A, Brown M, Chung C, Dave H, Denis A, Dodic N, Dossang A, Eddershaw P, Klimaszewska D, Haq I, Holmes DS, Hutchinson JP, Jagger AM, Jakhria T, Jigorel E, Liddle J, Lind K, Marciniak SJ, Messer J, Neu M, Olszewski A, Ordonez A, Ronzoni R, Rowedder J, Rüdiger M, Skinner S, Smith KJ, Terry R, Trottet L, Uings I, Wilson S, Zhu Z, Pearce AC. Development of a small molecule that corrects misfolding and increases secretion of Z α 1 -antitrypsin. EMBO Mol Med 2021; 13:e13167. [PMID: 33512066 PMCID: PMC7933930 DOI: 10.15252/emmm.202013167] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 12/08/2020] [Accepted: 12/10/2020] [Indexed: 01/23/2023] Open
Abstract
Severe α1 -antitrypsin deficiency results from the Z allele (Glu342Lys) that causes the accumulation of homopolymers of mutant α1 -antitrypsin within the endoplasmic reticulum of hepatocytes in association with liver disease. We have used a DNA-encoded chemical library to undertake a high-throughput screen to identify small molecules that bind to, and stabilise Z α1 -antitrypsin. The lead compound blocks Z α1 -antitrypsin polymerisation in vitro, reduces intracellular polymerisation and increases the secretion of Z α1 -antitrypsin threefold in an iPSC model of disease. Crystallographic and biophysical analyses demonstrate that GSK716 and related molecules bind to a cryptic binding pocket, negate the local effects of the Z mutation and stabilise the bound state against progression along the polymerisation pathway. Oral dosing of transgenic mice at 100 mg/kg three times a day for 20 days increased the secretion of Z α1 -antitrypsin into the plasma by sevenfold. There was no observable clearance of hepatic inclusions with respect to controls over the same time period. This study provides proof of principle that "mutation ameliorating" small molecules can block the aberrant polymerisation that underlies Z α1 -antitrypsin deficiency.
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Affiliation(s)
- David A Lomas
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
| | - James A Irving
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
| | | | | | | | | | | | | | | | | | | | | | | | - Imran Haq
- UCL RespiratoryRayne InstituteUniversity College LondonLondonUK
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