251
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Zhang G, Hu Y, Lu LG. Opportunity and challenge for diagnosis and treatment of hepatic fibrosis. Shijie Huaren Xiaohua Zazhi 2015; 23:5743-5749. [DOI: 10.11569/wcjd.v23.i36.5743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Hepatic fibrosis is a wound-healing response to all kinds of chronic liver injuries, which is characterized by extracellular matrix remodeling. Hepatic fibrosis ultimately leads to cirrhosis and even hepatic cell carcinoma. Thus, diagnosis and treatment of hepatic fibrosis are important for the management of chronic liver diseases. Recently, the study of hepatic fibrogenesis has witnessed tremendous progress, with many new diagnostic and therapeutic options emerging. This article mainly discusses the opportunity and challenge for diagnosis and treatment of hepatic fibrosis.
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252
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Maejima Y, Isobe M, Sadoshima J. Regulation of autophagy by Beclin 1 in the heart. J Mol Cell Cardiol 2015; 95:19-25. [PMID: 26546165 DOI: 10.1016/j.yjmcc.2015.10.032] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/19/2015] [Accepted: 10/29/2015] [Indexed: 12/12/2022]
Abstract
Dysregulation of autophagy in cardiomyocytes is implicated in various heart disease conditions. Beclin 1, a mammalian ortholog of yeast Atg6 and a core component of the autophagy machinery, plays a central role in the regulation of autophagy through activation of Vps34. Beclin 1's ability to activate Vps34 is tightly regulated via transcriptional regulation, miRNA, post-translational modification, and interaction with Beclin 1 binding proteins. Of these mechanisms, binding of Beclin 1 with Bcl-2 family proteins (Bcl-2/XL) that negatively regulate autophagy activity has been shown to be both positively and negatively regulated by various kinases, including DAPK, ROCK1, Mst1 and JNK1, in response to external stimuli. Beclin 1's interaction with Bcl-2/XL also secondarily affects apoptosis through regulation of pro-apoptotic BH3 domain containing proteins. Thus, modulation of Beclin 1 significantly influences both autophagy and apoptosis, thereby deeply affecting the survival and death of cardiomyocytes in the heart. In this review, we discuss the signaling mechanism of autophagy modulation through Beclin 1 and therapeutic potential of Beclin 1 in heart diseases.
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Affiliation(s)
- Yasuhiro Maejima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers-New Jersey Medical School, Newark, NJ, USA; Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers-New Jersey Medical School, Newark, NJ, USA.
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253
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Eisele YS, Monteiro C, Fearns C, Encalada SE, Wiseman RL, Powers ET, Kelly JW. Targeting protein aggregation for the treatment of degenerative diseases. Nat Rev Drug Discov 2015; 14:759-80. [PMID: 26338154 PMCID: PMC4628595 DOI: 10.1038/nrd4593] [Citation(s) in RCA: 288] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The aggregation of specific proteins is hypothesized to underlie several degenerative diseases, which are collectively known as amyloid disorders. However, the mechanistic connection between the process of protein aggregation and tissue degeneration is not yet fully understood. Here, we review current and emerging strategies to ameliorate aggregation-associated degenerative disorders, with a focus on disease-modifying strategies that prevent the formation of and/or eliminate protein aggregates. Persuasive pharmacological and genetic evidence now supports protein aggregation as the cause of postmitotic tissue dysfunction or loss. However, a more detailed understanding of the factors that trigger and sustain aggregate formation and of the structure-activity relationships underlying proteotoxicity is needed to develop future disease-modifying therapies.
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Affiliation(s)
- Yvonne S. Eisele
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Cecilia Monteiro
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Colleen Fearns
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Sandra E. Encalada
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, La Jolla, California 92037, USA
| | - R. Luke Wiseman
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Evan T. Powers
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Jeffery W. Kelly
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, California 92037, USA
- The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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254
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Lin CW, Chen YS, Lin CC, Chen YJ, Lo GH, Lee PH, Kuo PL, Dai CY, Huang JF, Chung WL, Yu ML. Amiodarone as an autophagy promoter reduces liver injury and enhances liver regeneration and survival in mice after partial hepatectomy. Sci Rep 2015; 5:15807. [PMID: 26515640 PMCID: PMC4626804 DOI: 10.1038/srep15807] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/05/2015] [Indexed: 12/17/2022] Open
Abstract
The deregulation of autophagy is involved in liver regeneration. Here, we investigated the role of autophagy in the regulation of liver regeneration after partial hepatectomy (PHx) and the development of pharmacological interventions for improved liver regeneration after PHx. We show that autophagy was activated in the early stages of liver regeneration following 70% PHx in vivo. Moreover, amiodarone was associated with a significant enhancement of autophagy, liver growth, and hepatocyte proliferation, along with reduced liver injury and the termination of liver regeneration due to decreased transforming growth factor-β1 expression after 70% PHx. The promotion of autophagy appeared to selectively increase the removal of damaged mitochondria. We also found that Atg7 knockdown or pretreatment with chloroquine aggravated the liver injury associated with 70% PHx and reduced liver growth and hepatocyte proliferation. Finally, amiodarone improved liver regeneration, survival, and liver injury after 90% PHx. In conclusion, our results indicate that autophagy plays an important role in mouse liver regeneration and that modulating autophagy with amiodarone may be an effective method of improving liver regeneration, increasing survival, and ameliorating liver injury following PHx.
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Affiliation(s)
- Chih-Wen Lin
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung.,Division of Gastroenterology and Hepatology, Department of Medicine, E-Da Hospital, I-Shou University, Kaohsiung.,Health Examination Center, E-Da Hospital, I-Shou University, Kaohsiung.,School of Medicine, College of Medicine, I-Shou University, Kaohsiung
| | - Yaw-Sen Chen
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung.,Department of Surgery, E-Da Hospital, I-Shou University, Kaohsiung
| | - Chih-Che Lin
- Department of Surgery, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung
| | - Yun-Ju Chen
- Department of Medical Research, E-Da Hospital, I-Shou University, Kaohsiung.,Department of Biological Science &Technology, I-Shou University, Kaohsiung
| | - Gin-Ho Lo
- Division of Gastroenterology and Hepatology, Department of Medicine, E-Da Hospital, I-Shou University, Kaohsiung.,School of Medicine, College of Medicine, I-Shou University, Kaohsiung
| | - Po-Huang Lee
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung.,Department of Surgery, E-Da Hospital, I-Shou University, Kaohsiung
| | - Po-Lin Kuo
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung
| | - Chia-Yen Dai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung.,Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung.,Faculty of Medicine, College of Medicine, and Center for Infectious Disease and Cancer Research, and Center for Lipid and Glycomedicine Research, Kaohsiung Medical University, Kaohsiung
| | - Jee-Fu Huang
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung.,Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung
| | - Wang-Long Chung
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung.,Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung
| | - Ming-Lung Yu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung.,Hepatobiliary Division, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung.,Faculty of Medicine, College of Medicine, and Center for Infectious Disease and Cancer Research, and Center for Lipid and Glycomedicine Research, Kaohsiung Medical University, Kaohsiung.,Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
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255
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Hidvegi T, Stolz DB, Alcorn JF, Yousem SA, Wang J, Leme AS, Houghton AM, Hale P, Ewing M, Cai H, Garchar EA, Pastore N, Annunziata P, Kaminski N, Pilewski J, Shapiro SD, Pak SC, Silverman GA, Brunetti-Pierri N, Perlmutter DH. Enhancing Autophagy with Drugs or Lung-directed Gene Therapy Reverses the Pathological Effects of Respiratory Epithelial Cell Proteinopathy. J Biol Chem 2015; 290:29742-57. [PMID: 26494620 DOI: 10.1074/jbc.m115.691253] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Indexed: 11/06/2022] Open
Abstract
Recent studies have shown that autophagy mitigates the pathological effects of proteinopathies in the liver, heart, and skeletal muscle but this has not been investigated for proteinopathies that affect the lung. This may be due at least in part to the lack of an animal model robust enough for spontaneous pathological effects from proteinopathies even though several rare proteinopathies, surfactant protein A and C deficiencies, cause severe pulmonary fibrosis. In this report we show that the PiZ mouse, transgenic for the common misfolded variant α1-antitrypsin Z, is a model of respiratory epithelial cell proteinopathy with spontaneous pulmonary fibrosis. Intracellular accumulation of misfolded α1-antitrypsin Z in respiratory epithelial cells of the PiZ model resulted in activation of autophagy, leukocyte infiltration, and spontaneous pulmonary fibrosis severe enough to elicit functional restrictive deficits. Treatment with autophagy enhancer drugs or lung-directed gene transfer of TFEB, a master transcriptional activator of the autophagolysosomal system, reversed these proteotoxic consequences. We conclude that this mouse is an excellent model of respiratory epithelial proteinopathy with spontaneous pulmonary fibrosis and that autophagy is an important endogenous proteostasis mechanism and an attractive target for therapy.
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Affiliation(s)
- Tunda Hidvegi
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | | | - John F Alcorn
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | | | | | | | | | - Pamela Hale
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Michael Ewing
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Houming Cai
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Evelyn Akpadock Garchar
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Nunzia Pastore
- Department of Translational Medicine, Federico II University, Naples, Italy, 80138
| | - Patrizia Annunziata
- Department of Translational Medicine, Federico II University, Naples, Italy, 80138
| | | | | | | | - Stephen C Pak
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224
| | - Gary A Silverman
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224, Cell Biology, and
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, Federico II University, Naples, Italy, 80138 Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy, 80131, and
| | - David H Perlmutter
- From the Departments of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania 15224, Cell Biology, and
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256
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Tran I, Ji C, Ni I, Min T, Tang D, Vij N. Role of Cigarette Smoke-Induced Aggresome Formation in Chronic Obstructive Pulmonary Disease-Emphysema Pathogenesis. Am J Respir Cell Mol Biol 2015; 53:159-73. [PMID: 25490051 DOI: 10.1165/rcmb.2014-0107oc] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Cigarette smoke (CS) exposure is known to induce proteostasis imbalance that can initiate accumulation of ubiquitinated proteins. Therefore, the primary goal of this study was to determine if first- and secondhand CS induces localization of ubiquitinated proteins in perinuclear spaces as aggresome bodies. Furthermore, we sought to determine the mechanism by which smoke-induced aggresome formation contributes to chronic obstructive pulmonary disease (COPD)-emphysema pathogenesis. Hence, Beas2b cells were treated with CS extract (CSE) for in vitro experimental analysis of CS-induced aggresome formation by immunoblotting, microscopy, and reporter assays, whereas chronic CS-exposed murine model and human COPD-emphysema lung tissues were used for validation. In preliminary analysis, we observed a significant (P < 0.01) increase in ubiquitinated protein aggregation in the insoluble protein fraction of CSE-treated Beas2b cells. We verified that CS-induced ubiquitin aggregrates are localized in the perinuclear spaces as aggresome bodies. These CS-induced aggresomes (P < 0.001) colocalize with autophagy protein microtubule-associated protein 1 light chain-3B(+) autophagy bodies, whereas U.S. Food and Drug Administration-approved autophagy-inducing drug (carbamazepine) significantly (P < 0.01) decreases their colocalization and expression, suggesting CS-impaired autophagy. Moreover, CSE treatment significantly increases valosin-containing protein-p62 protein-protein interaction (P < 0.0005) and p62 expression (aberrant autophagy marker; P < 0.0001), verifying CS-impaired autophagy as an aggresome formation mechanism. We also found that inhibiting protein synthesis by cycloheximide does not deplete CS-induced ubiquitinated protein aggregates, suggesting the role of CS-induced protein synthesis in aggresome formation. Next, we used an emphysema murine model to verify that chronic CS significantly (P < 0.0005) induces aggresome formation. Moreover, we observed that autophagy induction by carbamazepine inhibits CS-induced aggresome formation and alveolar space enlargement (P < 0.001), confirming involvement of aggresome bodies in COPD-emphysema pathogenesis. Finally, significantly higher p62 accumulation in smokers and severe COPD-emphysema lungs (Global Initiative for Chronic Obstructive Lung Disease Stage III/IV) as compared with normal nonsmokers (Global Initiative for Chronic Obstructive Lung Disease Stage 0) substantiates the pathogenic role of autophagy impairment in aggresome formation and COPD-emphysema progression. In conclusion, CS-induced aggresome formation is a novel mechanism involved in COPD-emphysema pathogenesis.
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Affiliation(s)
- Ian Tran
- Departments of 1 Pediatric Respiratory Science and.,2 Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Changhoon Ji
- Departments of 1 Pediatric Respiratory Science and.,2 Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Inzer Ni
- Departments of 1 Pediatric Respiratory Science and.,2 Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Taehong Min
- Departments of 1 Pediatric Respiratory Science and.,2 Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Danni Tang
- Departments of 1 Pediatric Respiratory Science and.,2 Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, Maryland; and
| | - Neeraj Vij
- Departments of 1 Pediatric Respiratory Science and.,3 College of Medicine, Central Michigan University, Mount Pleasant, Michigan
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257
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Joly P, Guillaud O, Hervieu V, Francina A, Mornex JF, Chapuis-Cellier C. Clinical heterogeneity and potential high pathogenicity of the Mmalton Alpha 1 antitrypsin allele at the homozygous, compound heterozygous and heterozygous states. Orphanet J Rare Dis 2015; 10:130. [PMID: 26446624 PMCID: PMC4596512 DOI: 10.1186/s13023-015-0350-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 10/01/2015] [Indexed: 11/20/2022] Open
Abstract
Background Alpha 1 antitrypsin (A1AT) deficiency (A1ATD) is potentially associated with a high degree of liver and/or lung disease. Apart from the most frequent deficiency alleles, Pi S and Pi Z, some A1AT alleles of clinical significance may be easily misdiagnosed. This is typically the case of the Pi Mmalton variant which shares the same ‘gain-of-function’ liver toxicity than Pi Z and the same ‘loss of function’ lung disease as well. Methods The biological diagnosis of A1ATD typically relies on a low serum concentration associated with an abnormal isoelectric focusing (IEF) pattern of migration. However, Sanger direct DNA sequencing may be required for deficiency alleles without biochemical expression (Null alleles) or for A1AT variants whose IEF profiles resemble the wild-type and sub-types M allele but with a low concentration. Results We report four cases of A1ATD involving the deficient Pi Mmalton allele with very different clinical expressions: (i) one Mmalton/Mmalton with liver fibrosis and cirrhosis, (ii) two Mmalton/Z with chronic pulmonary obstructive disease in one case and (iii) one M/Mmalton without liver or lung disease. In both cases, the correct diagnosis has necessitated a genetic analysis. Conclusions Our study provides another example of Pi Mmalton homozygosity associated with a severe liver disease that emphasizes the necessity of a not delayed diagnosis. The great clinical heterogeneity of the other genotypes (which is in agreement with the literature data) questions about the role of environmental and other modifier genes in the pathogenicity of A1ATD.
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Affiliation(s)
- Philippe Joly
- Unité de Pathologie Moléculaire du Globule Rouge, Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France. .,Centre de Recherche et d'Innovation sur le Sport (CRIS)-EA 647, Université Claude-Bernard Lyon 1, Villeurbanne, France. .,Labex GR-Ex, Institut Universitaire de France, Paris, France.
| | - Olivier Guillaud
- Service d'hépato-gastroentérologie, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Valérie Hervieu
- Service d'anatomie pathologique, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Alain Francina
- Unité de Pathologie Moléculaire du Globule Rouge, Laboratoire de Biochimie et de Biologie Moléculaire, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France.
| | - Jean-François Mornex
- Service de pneumologie, Groupement Hospitalier Est, Hospices Civils & Université Claude Bernard-Lyon 1, Bron, France.
| | - Colette Chapuis-Cellier
- Laboratoire d'Immunologie, Centre de Biologie Sud, Centre hospitalier Lyon-Sud, Hospices Civils & Université Claude Bernard-Lyon 1, Lyon, France.
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258
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Abstract
Hepatic neoplasia is a rare but serious complication of metabolic diseases in children. The risk of developing neoplasia, the age at onset, and the measures to prevent it differ in the various diseases. We review the most common metabolic disorders that are associated with a heightened risk of developing hepatocellular neoplasms, with a special emphasis on reviewing recent advances in the molecular pathogenesis of the disorders and pre-clinical therapeutic options. The cellular and genetic pathways driving carcinogenesis are poorly understood, but best understood in tyrosinemia.
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Affiliation(s)
- Deborah A Schady
- Department of Pathology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Angshumoy Roy
- Department of Pathology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
| | - Milton J Finegold
- Department of Pathology, Baylor College of Medicine, Texas Children's Hospital, Houston, TX 77030, USA
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259
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Vignaud H, Cullin C, Bouchecareilh M. [Alpha-1 antitrypsin deficiency: A model of alteration of protein homeostasis or proteostasis]. Rev Mal Respir 2015; 32:1059-71. [PMID: 26386628 DOI: 10.1016/j.rmr.2015.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 05/08/2015] [Indexed: 10/23/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is currently the ninth leading cause of death in France and is predicted to become the third leading cause of worldwide morbidity and mortality by 2020. Risk factors for COPD include exposure to tobacco, dusts and chemicals, asthma and alpha-1 antitrypsin deficiency. This genetic disease, significantly under-diagnosed and under-recognized, affects 1 in 2500 live births and is an important cause of lung and, occasionally, liver disease. Alpha-1 antitrypsin deficiency is a pathology of proteostasis-mediated protein folding and trafficking pathways. To date, there are only palliative therapeutic approaches for the symptoms associated with this hereditary disorder. Therefore, a more detailed understanding is required of the folding and trafficking biology governing alpha-1 antitrypsin biogenesis and its response to drugs. Here, we review the cell biological, biochemical and biophysical properties of alpha-1 antitrypsin and its variants, and we suggest that alpha-1 antitrypsin deficiency is an example of cell autonomous and non-autonomous challenges to proteostasis. Finally, we review emerging strategies that may be used to enhance the proteostasis system and protect the lung from alpha-1 antitrypsin deficiency.
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Affiliation(s)
- H Vignaud
- Institut de biochimie et génétique cellulaires, CNRS UMR 5095, université de Bordeaux, 1, rue Camille-Saint-Saëns, 33077 Bordeaux cedex, France
| | - C Cullin
- Institut de biochimie et génétique cellulaires, CNRS UMR 5095, université de Bordeaux, 1, rue Camille-Saint-Saëns, 33077 Bordeaux cedex, France
| | - M Bouchecareilh
- Institut de biochimie et génétique cellulaires, CNRS UMR 5095, université de Bordeaux, 1, rue Camille-Saint-Saëns, 33077 Bordeaux cedex, France.
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260
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Schaefer B, Haschka D, Finkenstedt A, Petersen BS, Theurl I, Henninger B, Janecke AR, Wang CY, Lin HY, Veits L, Vogel W, Weiss G, Franke A, Zoller H. Impaired hepcidin expression in alpha-1-antitrypsin deficiency associated with iron overload and progressive liver disease. Hum Mol Genet 2015; 24:6254-63. [PMID: 26310624 DOI: 10.1093/hmg/ddv348] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 08/19/2015] [Indexed: 01/25/2023] Open
Abstract
Liver disease due to alpha-1-antitrypsin deficiency (A1ATD) is associated with hepatic iron overload in a subgroup of patients. The underlying cause for this association is unknown. The aim of the present study was to define the genetics of this correlation and the effect of alpha-1-antitrypsin (A1AT) on the expression of the iron hormone hepcidin. Full exome and candidate gene sequencing were carried out in a family with A1ATD and hepatic iron overload. Regulation of hepcidin expression by A1AT was studied in primary murine hepatocytes. Cells co-transfected with hemojuvelin (HJV) and matriptase-2 (MT-2) were used as a model to investigate the molecular mechanism of this regulation. Observed familial clustering of hepatic iron overload with A1ATD suggests a genetic cause, but genotypes known to be associated with hemochromatosis were absent. Individuals homozygous for the A1AT Z-allele with environmental or genetic risk factors such as steatosis or heterozygosity for the HAMP non-sense mutation p.Arg59* presented with severe hepatic siderosis. In hepatocytes, A1AT induced hepcidin mRNA expression in a dose-dependent manner. Experiments in overexpressing cells show that A1AT reduces cleavage of the hepcidin inducing bone morphogenetic protein co-receptor HJV via inhibition of the membrane-bound serine protease MT-2. The acute-phase protein A1AT is an inducer of hepcidin expression. Through this mechanism, A1ATD could be a trigger of hepatic iron overload in genetically predisposed individuals or patients with environmental risk factors for hepatic siderosis.
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Affiliation(s)
| | - David Haschka
- Department of Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology
| | | | - Britt-Sabina Petersen
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Schittenhelmstrasse 12, 24105 Kiel, Germany
| | - Igor Theurl
- Department of Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology
| | - Benjamin Henninger
- Department of Radiology, Medical University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria
| | - Andreas R Janecke
- Department of Pediatrics I, Medical University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria, Division of Human Genetics, Medical University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria
| | - Chia-Yu Wang
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA and
| | - Herbert Y Lin
- Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA and
| | - Lothar Veits
- Institute of Pathology, Klinikum Bayreuth, Preuschwitzerstraße 101, 95445 Bayreuth, Germany
| | - Wolfgang Vogel
- Department of Medicine II, Gastroenterology and Hepatology
| | - Günter Weiss
- Department of Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology
| | - Andre Franke
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Schittenhelmstrasse 12, 24105 Kiel, Germany
| | - Heinz Zoller
- Department of Medicine II, Gastroenterology and Hepatology,
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261
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Liu Y, Zhang X, Chen W, Tan YL, Kelly JW. Fluorescence Turn-On Folding Sensor To Monitor Proteome Stress in Live Cells. J Am Chem Soc 2015; 137:11303-11. [PMID: 26305239 PMCID: PMC4755273 DOI: 10.1021/jacs.5b04366] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Proteome misfolding and/or aggregation, caused by a thermal perturbation or a related stress, transiently challenges the cellular protein homeostasis (proteostasis) network capacity of cells by consuming chaperone/chaperonin pathway and degradation pathway capacity. Developing protein client-based probes to quantify the cellular proteostasis network capacity in real time is highly desirable. Herein we introduce a small-molecule-regulated fluorescent protein folding sensor based on a thermo-labile mutant of the de novo designed retroaldolase (RA) enzyme. Since RA enzyme activity is not present in any cell, the protein folding sensor is bioorthogonal. The fluorogenic small molecule was designed to become fluorescent when it binds to and covalently reacts with folded and functional RA. Thus, in the first experimental paradigm, cellular proteostasis network capacity and its dynamics are reflected by RA-small molecule conjugate fluorescence, which correlates with the amount of folded and functional RA present, provided that pharmacologic chaperoning is minimized. In the second experimental scenario, the RA-fluorogenic probe conjugate is pre-formed in a cell by simply adding the fluorogenic probe to the cell culture media. Unreacted probe is then washed away before a proteome misfolding stress is applied in a pulse-chase-type experiment. Insufficient proteostasis network capacity is reflected by aggregate formation of the fluorescent RA-fluorogenic probe conjugate. Removal of the stress results in apparent RA-fluorogenic probe conjugate re-folding, mediated in part by the heat-shock response transcriptional program augmenting cytosolic proteostasis network capacity, and in part by time-dependent RA-fluorogenic probe conjugate degradation by cellular proteolysis.
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Affiliation(s)
- Yu Liu
- Department of Chemistry, ‡Department of Molecular and Experimental Medicine, and §The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Xin Zhang
- Department of Chemistry, ‡Department of Molecular and Experimental Medicine, and §The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Wentao Chen
- Department of Chemistry, ‡Department of Molecular and Experimental Medicine, and §The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Yun Lei Tan
- Department of Chemistry, ‡Department of Molecular and Experimental Medicine, and §The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
| | - Jeffery W Kelly
- Department of Chemistry, ‡Department of Molecular and Experimental Medicine, and §The Skaggs Institute for Chemical Biology, The Scripps Research Institute , La Jolla, California 92037, United States
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262
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Abstract
Alpha-1 antitrypsin deficiency is the leading cause of childhood liver failure and one of the most common lethal genetic diseases. The disease-causing mutant A1AT-Z fails to fold correctly and accumulates in the endoplasmic reticulum (ER) of the liver, resulting in hepatic fibrosis and hepatocellular carcinoma in a subset of patients. Furthermore, A1AT-Z sequestration in hepatocytes leads to a reduction in A1AT secretion into the serum, causing panacinar emphysema in adults. The purpose of this work was to elucidate the details by which A1AT-Z is degraded in hepatic cell lines. We identified the ubiquitin ligase FBG1, which has been previously shown to degrade proteins by both the ubiquitin proteasome pathway and autophagy, as being key to A1AT-Z degradation. Using chemical and genetic approaches we show that FBG1 degrades A1AT-Z through both the ubiquitin proteasome system and autophagy. Overexpression of FBG1 decreases the half-life of A1AT-Z and knocking down FBG1 in a hepatic cell line, and in mice results in an increase in ATAT. Finally, we show that FBG1 degrades A1AT-Z through a Beclin1-dependent arm of autophagy. In our model, FBG1 acts as a safety ubiquitin ligase, whose function is to re-ubiquitinate ER proteins that have previously undergone de-ubiquitination to ensure they are degraded.
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263
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Mao YQ, Fan XM. Autophagy: A new therapeutic target for liver fibrosis. World J Hepatol 2015; 7:1982-1986. [PMID: 26261688 PMCID: PMC4528272 DOI: 10.4254/wjh.v7.i16.1982] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 05/26/2015] [Accepted: 06/19/2015] [Indexed: 02/06/2023] Open
Abstract
Hepatic fibrosis is a wound-healing response to liver injury and the result of imbalance of extracellular matrix (ECM) accumulation and degradation. The relentless production and progressive accumulation of ECM can lead to end-stage liver disease. Although significant progress has been achieved in elucidating the mechanisms of fibrogenesis, effective anti-fibrotic strategies are still lacking. Autophagy is an intracellular process of self-digestion of defective organelles to provide material recycling or energy for cell survival. Autophagy has been implicated in the pathophysiology of many human disorders including hepatic fibrosis. However, the exact relationships between autophagy and hepatic fibrosis are not totally clear and need further investigations. A new therapeutic target for liver fibrosis could be developed with a better understanding of autophagy.
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264
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Interactions between Autophagy and Bacterial Toxins: Targets for Therapy? Toxins (Basel) 2015; 7:2918-58. [PMID: 26248079 PMCID: PMC4549733 DOI: 10.3390/toxins7082918] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.
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265
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Small-molecule enhancers of autophagy modulate cellular disease phenotypes suggested by human genetics. Proc Natl Acad Sci U S A 2015. [PMID: 26195741 DOI: 10.1073/pnas.1512289112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Studies of human genetics and pathophysiology have implicated the regulation of autophagy in inflammation, neurodegeneration, infection, and autoimmunity. These findings have motivated the use of small-molecule probes to study how modulation of autophagy affects disease-associated phenotypes. Here, we describe the discovery of the small-molecule probe BRD5631 that is derived from diversity-oriented synthesis and enhances autophagy through an mTOR-independent pathway. We demonstrate that BRD5631 affects several cellular disease phenotypes previously linked to autophagy, including protein aggregation, cell survival, bacterial replication, and inflammatory cytokine production. BRD5631 can serve as a valuable tool for studying the role of autophagy in the context of cellular homeostasis and disease.
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266
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Tafaleng EN, Chakraborty S, Han B, Hale P, Wu W, Soto-Gutierrez A, Feghali-Bostwick CA, Wilson AA, Kotton DN, Nagaya M, Strom SC, Chowdhury JR, Stolz DB, Perlmutter DH, Fox IJ. Induced pluripotent stem cells model personalized variations in liver disease resulting from α1-antitrypsin deficiency. Hepatology 2015; 62:147-57. [PMID: 25690322 PMCID: PMC4482790 DOI: 10.1002/hep.27753] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/13/2015] [Indexed: 12/15/2022]
Abstract
UNLABELLED In the classical form of α1-antitrypsin deficiency (ATD), aberrant intracellular accumulation of misfolded mutant α1-antitrypsin Z (ATZ) in hepatocytes causes hepatic damage by a gain-of-function, "proteotoxic" mechanism. Whereas some ATD patients develop severe liver disease (SLD) that necessitates liver transplantation, others with the same genetic defect completely escape this clinical phenotype. We investigated whether induced pluripotent stem cells (iPSCs) from ATD individuals with or without SLD could model these personalized variations in hepatic disease phenotypes. Patient-specific iPSCs were generated from ATD patients and a control and differentiated into hepatocyte-like cells (iHeps) having many characteristics of hepatocytes. Pulse-chase and endoglycosidase H analysis demonstrate that the iHeps recapitulate the abnormal accumulation and processing of the ATZ molecule, compared to the wild-type AT molecule. Measurements of the fate of intracellular ATZ show a marked delay in the rate of ATZ degradation in iHeps from SLD patients, compared to those from no liver disease patients. Transmission electron microscopy showed dilated rough endoplasmic reticulum in iHeps from all individuals with ATD, not in controls, but globular inclusions that are partially covered with ribosomes were observed only in iHeps from individuals with SLD. CONCLUSION iHeps model the individual disease phenotypes of ATD patients with more rapid degradation of misfolded ATZ and lack of globular inclusions in cells from patients who have escaped liver disease. The results support the concept that "proteostasis" mechanisms, such as intracellular degradation pathways, play a role in observed variations in clinical phenotype and show that iPSCs can potentially be used to facilitate predictions of disease susceptibility for more precise and timely application of therapeutic strategies.
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Affiliation(s)
- Edgar N. Tafaleng
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA
| | - Souvik Chakraborty
- Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA,Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Bing Han
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA
| | - Pamela Hale
- Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA,Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Wanquan Wu
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA
| | - Alejandro Soto-Gutierrez
- Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA,Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | | | - Andrew A. Wilson
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Darrell N. Kotton
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Masaki Nagaya
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Stephen C. Strom
- Department of Laboratory Medicine, Division of Pathology, Karolinska Institutet, Stockholm, Sweden
| | | | - Donna B. Stolz
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - David H. Perlmutter
- Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA,Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Ira J. Fox
- Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA,Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA
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267
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Affiliation(s)
- David C Rubinsztein
- Department of Medical Genetics, University of Cambridge, Cambridge Institute for Medical Research, Cambridge CB2 0XY, UK
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268
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Two New Considerations for Improving the Diagnosis of α1-Antitrypsin Deficiency-Associated Liver Disease. Dig Dis Sci 2015; 60:1511-3. [PMID: 25634676 PMCID: PMC4456220 DOI: 10.1007/s10620-015-3553-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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269
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Tsang KY, Tsang SW, Chan D, Cheah KSE. The chondrocytic journey in endochondral bone growth and skeletal dysplasia. ACTA ACUST UNITED AC 2015; 102:52-73. [PMID: 24677723 DOI: 10.1002/bdrc.21060] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 02/23/2014] [Indexed: 12/29/2022]
Abstract
The endochondral bones of the skeleton develop from a cartilage template and grow via a process involving a cascade of chondrocyte differentiation steps culminating in formation of a growth plate and the replacement of cartilage by bone. This process of endochondral ossification, driven by the generation of chondrocytes and their subsequent proliferation, differentiation, and production of extracellular matrix constitute a journey, deviation from which inevitably disrupts bone growth and development, and is the basis of human skeletal dysplasias with a wide range of phenotypic severity, from perinatal lethality to progressively deforming. This highly coordinated journey of chondrocyte specification and fate determination is controlled by a myriad of intrinsic and extrinsic factors. SOX9 is the master transcription factor that, in concert with varying partners along the way, directs the different phases of the journey from mesenchymal condensation, chondrogenesis, differentiation, proliferation, and maturation. Extracellular signals, including bone morphogenetic proteins, wingless-related MMTV integration site (WNT), fibroblast growth factor, Indian hedgehog, and parathyroid hormone-related peptide, are all indispensable for growth plate chondrocytes to align and organize into the appropriate columnar architecture and controls their maturation and transition to hypertrophy. Chondrocyte hypertrophy, marked by dramatic volume increase in phases, is controlled by transcription factors SOX9, Runt-related transcription factor, and FOXA2. Hypertrophic chondrocytes mediate the cartilage to bone transition and concomitantly face a live-or-die situation, a subject of much debate. We review recent insights into the coordination of the phases of the chondrocyte journey, and highlight the need for a systems level understanding of the regulatory networks that will facilitate the development of therapeutic approaches for skeletal dysplasia.
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Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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270
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Wilson AA, Ying L, Liesa M, Segeritz CP, Mills JA, Shen SS, Jean J, Lonza GC, Liberti DC, Lang AH, Nazaire J, Gower AC, Müeller FJ, Mehta P, Ordóñez A, Lomas DA, Vallier L, Murphy GJ, Mostoslavsky G, Spira A, Shirihai OS, Ramirez MI, Gadue P, Kotton DN. Emergence of a stage-dependent human liver disease signature with directed differentiation of alpha-1 antitrypsin-deficient iPS cells. Stem Cell Reports 2015; 4:873-85. [PMID: 25843048 PMCID: PMC4437473 DOI: 10.1016/j.stemcr.2015.02.021] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 02/25/2015] [Accepted: 02/25/2015] [Indexed: 12/14/2022] Open
Abstract
Induced pluripotent stem cells (iPSCs) provide an inexhaustible source of cells for modeling disease and testing drugs. Here we develop a bioinformatic approach to detect differences between the genomic programs of iPSCs derived from diseased versus normal human cohorts as they emerge during in vitro directed differentiation. Using iPSCs generated from a cohort carrying mutations (PiZZ) in the gene responsible for alpha-1 antitrypsin (AAT) deficiency, we find that the global transcriptomes of PiZZ iPSCs diverge from normal controls upon differentiation to hepatic cells. Expression of 135 genes distinguishes PiZZ iPSC-hepatic cells, providing potential clues to liver disease pathogenesis. The disease-specific cells display intracellular accumulation of mutant AAT protein, resulting in increased autophagic flux. Furthermore, we detect beneficial responses to the drug carbamazepine, which further augments autophagic flux, but adverse responses to known hepatotoxic drugs. Our findings support the utility of iPSCs as tools for drug development or prediction of toxicity.
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Affiliation(s)
- Andrew A Wilson
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Lei Ying
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Marc Liesa
- Evans Center for Interdisciplinary Research, Department of Medicine, Mitochondria ARC, Boston University School of Medicine, Boston, MA 02118, USA
| | - Charis-Patricia Segeritz
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine and Department of Surgery, University of Cambridge, Cambridge CB2 0SZ, UK
| | - Jason A Mills
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Steven S Shen
- Division of Computational Biomedicine and Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Jyhchang Jean
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Geordie C Lonza
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Derek C Liberti
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Alex H Lang
- Physics Department, Boston University, Boston, MA 02215, USA
| | - Jean Nazaire
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Adam C Gower
- Division of Computational Biomedicine and Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Franz-Josef Müeller
- Zentrum für Integrative Psychiatrie, Universitätsklinikums Schleswig-Holstein, Kiel 24105, Germany
| | - Pankaj Mehta
- Physics Department, Boston University, Boston, MA 02215, USA
| | - Adriana Ordóñez
- Cambridge Institute for Medical Research, Cambridge CB0 2XY, UK
| | - David A Lomas
- Cambridge Institute for Medical Research, Cambridge CB0 2XY, UK
| | - Ludovic Vallier
- Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine and Department of Surgery, University of Cambridge, Cambridge CB2 0SZ, UK
| | - George J Murphy
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Gustavo Mostoslavsky
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Avrum Spira
- Division of Computational Biomedicine and Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Orian S Shirihai
- Evans Center for Interdisciplinary Research, Department of Medicine, Mitochondria ARC, Boston University School of Medicine, Boston, MA 02118, USA
| | - Maria I Ramirez
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, MA 02118, USA
| | - Paul Gadue
- Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Darrell N Kotton
- Center for Regenerative Medicine (CReM) of Boston University and Boston Medical Center, Boston, MA 02118, USA.
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271
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AMDE-1 is a dual function chemical for autophagy activation and inhibition. PLoS One 2015; 10:e0122083. [PMID: 25894744 PMCID: PMC4403922 DOI: 10.1371/journal.pone.0122083] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 02/10/2015] [Indexed: 11/19/2022] Open
Abstract
Autophagy is the process by which cytosolic components and organelles are delivered to the lysosome for degradation. Autophagy plays important roles in cellular homeostasis and disease pathogenesis. Small chemical molecules that can modulate autophagy activity may have pharmacological value for treating diseases. Using a GFP-LC3-based high content screening assay we identified a novel chemical that is able to modulate autophagy at both initiation and degradation levels. This molecule, termed as Autophagy Modulator with Dual Effect-1 (AMDE-1), triggered autophagy in an Atg5-dependent manner, recruiting Atg16 to the pre-autophagosomal site and causing LC3 lipidation. AMDE-1 induced autophagy through the activation of AMPK, which inactivated mTORC1 and activated ULK1. AMDE-1did not affect MAP kinase, JNK or oxidative stress signaling for autophagy induction. Surprisingly, treatment with AMDE-1 resulted in impairment in autophagic flux and inhibition of long-lived protein degradation. This inhibition was correlated with a reduction in lysosomal degradation capacity but not with autophagosome-lysosome fusion. Further analysis indicated that AMDE-1 caused a reduction in lysosome acidity and lysosomal proteolytic activity, suggesting that it suppressed general lysosome function. AMDE-1 thus also impaired endocytosis-mediated EGF receptor degradation. The dual effects of AMDE-1 on autophagy induction and lysosomal degradation suggested that its net effect would likely lead to autophagic stress and lysosome dysfunction, and therefore cell death. Indeed, AMDE-1 triggered necroptosis and was preferentially cytotoxic to cancer cells. In conclusion, this study identified a new class of autophagy modulators with dual effects, which can be explored for potential uses in cancer therapy.
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272
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Seki E, Brenner DA. Recent advancement of molecular mechanisms of liver fibrosis. JOURNAL OF HEPATO-BILIARY-PANCREATIC SCIENCES 2015; 22:512-8. [PMID: 25869468 DOI: 10.1002/jhbp.245] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/12/2015] [Indexed: 12/17/2022]
Abstract
Liver fibrosis occurs in response to any etiology of chronic liver injury including hepatitis B and C, alcohol consumption, fatty liver disease, cholestasis, and autoimmune hepatitis. Hepatic stellate cells (HSCs) are the primary source of activated myofibroblasts that produce extracellular matrix (ECM) in the liver. Various inflammatory and fibrogenic pathways contribute to the activation of HSCs. Recent studies also discovered that liver fibrosis is reversible and activated HSCs can revert to quiescent HSCs when causative agents are removed. Although the basic research for liver fibrosis has progressed remarkably, sensitive and specific biomarkers as non-invasive diagnostic tools, and effective anti-fibrotic agents have not been developed yet. This review highlights the recent advances in cellular and molecular mechanisms of liver fibrosis, especially focusing on origin of myofibroblasts, inflammatory signaling, autophagy, cellular senescence, HSC inactivation, angiogenesis, and reversibility of liver fibrosis.
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Affiliation(s)
- Ekihiro Seki
- Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, 8700 Beverly Blvd, DAVIS, Suite D2099, Los Angeles, CA, 90048, USA.
| | - David A Brenner
- School of Medicine, University of California San Diego, La Jolla, CA, USA
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273
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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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274
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Devaraneni PK, Martin GM, Olson EM, Zhou Q, Shyng SL. Structurally distinct ligands rescue biogenesis defects of the KATP channel complex via a converging mechanism. J Biol Chem 2015; 290:7980-91. [PMID: 25637631 DOI: 10.1074/jbc.m114.634576] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Small molecules that correct protein misfolding and misprocessing defects offer a potential therapy for numerous human diseases. However, mechanisms underlying pharmacological correction of such defects, especially in heteromeric complexes with structurally diverse constituent proteins, are not well understood. Here we investigate how two chemically distinct compounds, glibenclamide and carbamazepine, correct biogenesis defects in ATP-sensitive potassium (KATP) channels composed of sulfonylurea receptor 1 (SUR1) and Kir6.2. We present evidence that despite structural differences, carbamazepine and glibenclamide compete for binding to KATP channels, and both drugs share a binding pocket in SUR1 to exert their effects. Moreover, both compounds engage Kir6.2, in particular the distal N terminus of Kir6.2, which is involved in normal channel biogenesis, for their chaperoning effects on SUR1 mutants. Conversely, both drugs can correct channel biogenesis defects caused by Kir6.2 mutations in a SUR1-dependent manner. Using an unnatural, photocross-linkable amino acid, azidophenylalanine, genetically encoded in Kir6.2, we demonstrate in living cells that both drugs promote interactions between the distal N terminus of Kir6.2 and SUR1. These findings reveal a converging pharmacological chaperoning mechanism wherein glibenclamide and carbamazepine stabilize the heteromeric subunit interface critical for channel biogenesis to overcome defective biogenesis caused by mutations in individual subunits.
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Affiliation(s)
- Prasanna K Devaraneni
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Gregory M Martin
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Erik M Olson
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Qing Zhou
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
| | - Show-Ling Shyng
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239
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275
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Ferris SP, Kodali VK, Kaufman RJ. Glycoprotein folding and quality-control mechanisms in protein-folding diseases. Dis Model Mech 2015; 7:331-41. [PMID: 24609034 PMCID: PMC3944493 DOI: 10.1242/dmm.014589] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Biosynthesis of proteins – from translation to folding to export – encompasses a complex set of events that are exquisitely regulated and scrutinized to ensure the functional quality of the end products. Cells have evolved to capitalize on multiple post-translational modifications in addition to primary structure to indicate the folding status of nascent polypeptides to the chaperones and other proteins that assist in their folding and export. These modifications can also, in the case of irreversibly misfolded candidates, signal the need for dislocation and degradation. The current Review focuses on the glycoprotein quality-control (GQC) system that utilizes protein N-glycosylation and N-glycan trimming to direct nascent glycopolypeptides through the folding, export and dislocation pathways in the endoplasmic reticulum (ER). A diverse set of pathological conditions rooted in defective as well as over-vigilant ER quality-control systems have been identified, underlining its importance in human health and disease. We describe the GQC pathways and highlight disease and animal models that have been instrumental in clarifying our current understanding of these processes.
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Affiliation(s)
- Sean P Ferris
- Department of Biological Chemistry and Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
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276
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Lee S, Kim JS. Mitophagy: therapeutic potentials for liver disease and beyond. Toxicol Res 2015; 30:243-50. [PMID: 25584143 PMCID: PMC4289924 DOI: 10.5487/tr.2014.30.4.243] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 12/26/2014] [Accepted: 12/29/2014] [Indexed: 01/12/2023] Open
Abstract
Mitochondrial integrity is critical for maintaining proper cellular functions. A key aspect of regulating mitochondrial homeostasis is removing damaged mitochondria through autophagy, a process called mitophagy. Autophagy dysfunction in various disease states can inactivate mitophagy and cause cell death, and defects in mitophagy are becoming increasingly recognized in a wide range of diseases from liver injuries to neurodegenerative diseases. Here we highlight our current knowledge on the mechanisms of mitophagy, and discuss how alterations in mitophagy contribute to disease pathogenesis. We also discuss mitochondrial dynamics and potential interactions between mitochondrial fusion, fission and mitophagy.
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Affiliation(s)
- Sooyeon Lee
- Department of Surgery, University of Florida, Gainesville, FL 32610, USA
| | - Jae-Sung Kim
- Department of Surgery, University of Florida, Gainesville, FL 32610, USA
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277
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Abstract
Defects in autophagy have been linked to a wide range of medical illnesses, including cancer as well as infectious, neurodegenerative, inflammatory, and metabolic diseases. These observations have led to the hypothesis that autophagy inducers may prevent or treat certain clinical conditions. Lifestyle and nutritional factors, such as exercise and caloric restriction, may exert their known health benefits through the autophagy pathway. Several currently available FDA-approved drugs have been shown to enhance autophagy, and this autophagy-enhancing action may be repurposed for use in novel clinical indications. The development of new drugs that are designed to be more selective inducers of autophagy function in target organs is expected to maximize clinical benefits while minimizing toxicity. This Review summarizes the rationale and current approaches for developing autophagy inducers in medicine, the factors to be considered in defining disease targets for such therapy, and the potential benefits of such treatment for human health.
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278
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279
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Hauff P, Gottwald U, Ocker M. Early to Phase II drugs currently under investigation for the treatment of liver fibrosis. Expert Opin Investig Drugs 2014; 24:309-27. [PMID: 25547844 DOI: 10.1517/13543784.2015.997874] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Chronic liver diseases represent a high unmet medical need and are characterized by persistent inflammation, parenchymal damage and fibrotic remodeling, leading eventually to cirrhosis and hepatic failure. Besides the persisting high prevalence of chronic viral hepatitis B and C, the dramatic increase in nonalcoholic steatohepatitis is now considered to be a major pathophysiologic driver for fibrosis development and subsequently cirrhosis. Increasing evidence suggests that also liver cirrhosis can regress when treated adequately. AREAS COVERED Herein, the authors review the underlying pathophysiologic mechanisms leading to fibrotic remodeling in the liver. They also highlight the options for novel treatment strategies by using molecular targeted agents. EXPERT OPINION New in vitro and preclinical animal models, and the careful selection of patients with high disease dynamics for clinical studies, provide a sound basis for the clinical development of antifibrotic agents in humans. Surrogate parameters of liver function, inflammation, tissue remodeling and damage, as well as noninvasive imaging techniques, can be applied in clinical trials to provide fast readouts and novel and reliable endpoints for trial design, and provide an attractive regulatory environment for this emerging disease area.
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280
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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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281
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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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282
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Tannous A, Patel N, Tamura T, Hebert DN. Reglucosylation by UDP-glucose:glycoprotein glucosyltransferase 1 delays glycoprotein secretion but not degradation. Mol Biol Cell 2014; 26:390-405. [PMID: 25428988 PMCID: PMC4310732 DOI: 10.1091/mbc.e14-08-1254] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
UDP-glucose:glycoprotein glucosyltransferase 1 (UGT1) is a central quality control gatekeeper in the mammalian endoplasmic reticulum (ER). The reglucosylation of glycoproteins supports their rebinding to the carbohydrate-binding ER molecular chaperones calnexin and calreticulin. A cell-based reglucosylation assay was used to investigate the role of UGT1 in ER protein surveillance or the quality control process. UGT1 was found to modify wild-type proteins or proteins that are expected to eventually traffic out of the ER through the secretory pathway. Trapping of reglucosylated wild-type substrates in their monoglucosylated state delayed their secretion. Whereas terminally misfolded substrates or off-pathway proteins were most efficiently reglucosylated by UGT1, the trapping of these mutant substrates in their reglucosylated or monoglucosylated state did not delay their degradation by the ER-associated degradation pathway. This indicated that monoglucosylated mutant proteins were actively extracted from the calnexin/calreticulin binding-reglucosylation cycle for degradation. Therefore trapping proteins in their monoglucosylated state was sufficient to delay their exit to the Golgi but had no effect on their rate of degradation, suggesting that the degradation selection process progressed in a dominant manner that was independent of reglucosylation and the glucose-containing A-branch on the substrate glycans.
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Affiliation(s)
- Abla Tannous
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Nishant Patel
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Taku Tamura
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | - Daniel N Hebert
- Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
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283
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Maejima Y, Chen Y, Isobe M, Gustafsson ÅB, Kitsis RN, Sadoshima J. Recent progress in research on molecular mechanisms of autophagy in the heart. Am J Physiol Heart Circ Physiol 2014; 308:H259-68. [PMID: 25398984 DOI: 10.1152/ajpheart.00711.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dysregulation of autophagy, an evolutionarily conserved process for degradation of long-lived proteins and organelles, has been implicated in the pathogenesis of human disease. Recent research has uncovered pathways that control autophagy in the heart and molecular mechanisms by which alterations in this process affect cardiac structure and function. Although initially thought to be a nonselective degradation process, autophagy, as it has become increasingly clear, can exhibit specificity in the degradation of molecules and organelles, such as mitochondria. Furthermore, it has been shown that autophagy is involved in a wide variety of previously unrecognized cellular functions, such as cell death and metabolism. A growing body of evidence suggests that deviation from appropriate levels of autophagy causes cellular dysfunction and death, which in turn leads to heart disease. Here, we review recent advances in understanding the role of autophagy in heart disease, highlight unsolved issues, and discuss the therapeutic potential of modulating autophagy in heart disease.
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Affiliation(s)
- Yasuhiro Maejima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers-New Jersey Medical School, Newark, New Jersey; Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Yun Chen
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Diabetes Research Center, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Åsa B Gustafsson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Diabetes Research Center, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, New York
| | - Junichi Sadoshima
- Department of Cell Biology and Molecular Medicine, Cardiovascular Research Institute, Rutgers-New Jersey Medical School, Newark, New Jersey;
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284
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Guiliano DB, Fussell H, Lenart I, Tsao E, Nesbeth D, Fletcher AJ, Campbell EC, Yousaf N, Williams S, Santos S, Cameron A, Towers GJ, Kellam P, Hebert DN, Gould K, Powis SJ, Antoniou AN. Endoplasmic reticulum degradation-enhancing α-mannosidase-like protein 1 targets misfolded HLA-B27 dimers for endoplasmic reticulum-associated degradation. Arthritis Rheumatol 2014; 66:2976-88. [PMID: 25132672 PMCID: PMC4399817 DOI: 10.1002/art.38809] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 07/29/2014] [Indexed: 12/29/2022]
Abstract
OBJECTIVE HLA-B27 forms misfolded heavy chain dimers, which may predispose individuals to inflammatory arthritis by inducing endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). This study was undertaken to define the role of the UPR-induced ER-associated degradation (ERAD) pathway in the disposal of HLA-B27 dimeric conformers. METHODS HeLa cell lines expressing only 2 copies of a carboxy-terminally Sv5-tagged HLA-B27 were generated. The ER stress-induced protein ER degradation-enhancing α-mannosidase-like protein 1 (EDEM1) was overexpressed by transfection, and dimer levels were monitored by immunoblotting. EDEM1, the UPR-associated transcription factor X-box binding protein 1 (XBP-1), the E3 ubiquitin ligase hydroxymethylglutaryl-coenzyme A reductase degradation 1 (HRD1), and the degradation-associated proteins derlin 1 and derlin 2 were inhibited using either short hairpin RNA or dominant-negative mutants. The UPR-associated ERAD of HLA-B27 was confirmed using ER stress-inducing pharamacologic agents in kinetic and pulse chase assays. RESULTS We demonstrated that UPR-induced machinery can target HLA-B27 dimers and that dimer formation can be controlled by alterations to expression levels of components of the UPR-induced ERAD pathway. HLA-B27 dimers and misfolded major histocompatibility complex class I monomeric molecules bound to EDEM1 were detected, and overexpression of EDEM1 led to inhibition of HLA-B27 dimer formation. EDEM1 inhibition resulted in up-regulation of HLA-B27 dimers, while UPR-induced ERAD of dimers was prevented in the absence of EDEM1. HLA-B27 dimer formation was also enhanced in the absence of XBP-1, HRD1, and derlins 1 and 2. CONCLUSION The present findings indicate that the UPR ERAD pathway can dispose of HLA-B27 dimers, thus presenting a potential novel therapeutic target for modulation of HLA-B27-associated inflammatory disease.
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Affiliation(s)
- David B. Guiliano
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
- School of Health, Sport and Bioscience, University of East London, London, E15 4LZ
| | - Helen Fussell
- Histocompatibility and Immunogenetics Department, NHS Blood and Transplant, Colindale Blood Centre, Colindale Avenue, London, NW9 5BG
| | - Izabela Lenart
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | - Edward Tsao
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | - Darren Nesbeth
- The Advanced Centre for Biochemical Engineering, University College London, Gower Street, London, WC1E 7JE
| | - Adam J. Fletcher
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | | | - Nasim Yousaf
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | - Sarah Williams
- School of Medicine, University of St. Andrews, Fife, Scotland, KY16 9TF
| | - Susana Santos
- INEB-Instituto de Engenharia Biomedica, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
| | - Amy Cameron
- School of Medicine, University of St. Andrews, Fife, Scotland, KY16 9TF
| | - Greg J. Towers
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | - Paul Kellam
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
| | - Daniel N. Hebert
- Biochemistry and Molecular Biology, 701 N. Pleasant St. LGRT 1228, University of Massachusetts, Amherst, MA 01003
| | - Keith Gould
- Wright-Fleming Institute, Imperial College London, London, England, W2 1PG
| | - Simon J. Powis
- School of Medicine, University of St. Andrews, Fife, Scotland, KY16 9TF
| | - Antony N. Antoniou
- Division of Infection and Immunity/Centre of Rheumatology, Rayne Building, 5 University Street, University College London, London, WC1E 6JF
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285
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Donohue TM, Thomes PG. Ethanol-induced oxidant stress modulates hepatic autophagy and proteasome activity. Redox Biol 2014; 3:29-39. [PMID: 25462063 PMCID: PMC4297932 DOI: 10.1016/j.redox.2014.10.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 02/07/2023] Open
Abstract
In this review, we describe research findings on the effects of alcohol exposure on two major catabolic systems in liver cells: the ubiquitin-proteasome system (UPS) and autophagy. These hydrolytic systems are not unique to liver cells; they exist in all eukaryotic tissues and cells. However, because the liver is the principal site of ethanol metabolism, it sustains the greatest damage from heavy drinking. Thus, the focus of this review is to specifically describe how ethanol oxidation modulates the activities of the UPS and autophagy and the mechanisms by which these changes contribute to the pathogenesis of alcohol-induced liver injury. Here, we describe the history and the importance of cellular hydrolytic systems, followed by a description of each catabolic pathway and the differential modulation of each by ethanol exposure. Overall, the evidence for an involvement of these catabolic systems in the pathogenesis of alcoholic liver disease is quite strong. It underscores their importance, not only as effective means of cellular recycling and eventual energy generation, but also as essential components of cellular defense.
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Affiliation(s)
- Terrence M Donohue
- Research Service (151), VA-Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; Department of Internal Medicine, College of Medicine, USA; Department of Biochemistry and Molecular Biology, College of Medicine, USA; Department of Pathology and Microbiology, College of Medicine, USA; The Center for Environmental Health and Toxicology, College of Public Health, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Paul G Thomes
- Research Service (151), VA-Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; Department of Internal Medicine, College of Medicine, USA
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286
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Lu Y, Dong S, Hao B, Li C, Zhu K, Guo W, Wang Q, Cheung KH, Wong CWM, Wu WT, Markus H, Yue J. Vacuolin-1 potently and reversibly inhibits autophagosome-lysosome fusion by activating RAB5A. Autophagy 2014; 10:1895-905. [PMID: 25483964 PMCID: PMC4502727 DOI: 10.4161/auto.32200] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Autophagy is a catabolic lysosomal degradation process essential for cellular homeostasis and cell survival. Dysfunctional autophagy has been associated with a wide range of human diseases, e.g., cancer and neurodegenerative diseases. A large number of small molecules that modulate autophagy have been widely used to dissect this process and some of them, e.g., chloroquine (CQ), might be ultimately applied to treat a variety of autophagy-associated human diseases. Here we found that vacuolin-1 potently and reversibly inhibited the fusion between autophagosomes and lysosomes in mammalian cells, thereby inducing the accumulation of autophagosomes. Interestingly, vacuolin-1 was less toxic but at least 10-fold more potent in inhibiting autophagy compared with CQ. Vacuolin-1 treatment also blocked the fusion between endosomes and lysosomes, resulting in a defect in general endosomal-lysosomal degradation. Treatment of cells with vacuolin-1 alkalinized lysosomal pH and decreased lysosomal Ca2+ content. Besides marginally inhibiting vacuolar ATPase activity, vacuolin-1 treatment markedly activated RAB5A GTPase activity. Expression of a dominant negative mutant of RAB5A or RAB5A knockdown significantly inhibited vacuolin-1-induced autophagosome-lysosome fusion blockage, whereas expression of a constitutive active form of RAB5A suppressed autophagosome-lysosome fusion. These data suggest that vacuolin-1 activates RAB5A to block autophagosome-lysosome fusion. Vacuolin-1 and its analogs present a novel class of drug that can potently and reversibly modulate autophagy.
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Key Words
- ATG, autophagy-related
- BAF, bafilomycin A1
- CQ, chloroquine
- CTSB, cathepsin B
- CTSL, cathepsin L
- EGFR, epidermal growth factor receptor
- GFP, green fluorescent protein
- GPN, glycyl-l-phenylalanine 2-naphthylamide
- LAMP1, lysosomal-associated membrane protein 1
- Leup, leupeptin
- MAP1LC3, microtubule-associated protein 1 light chain 3
- MTOR, mechanistic target of rapamycin
- RAB5A
- RFP, red fluorescent protein
- autophagosomes
- endosomes
- lysosomes
- pH
- tfLC3, tandem fluorescence-tagged LC3
- vacuolin-1
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Affiliation(s)
- Yingying Lu
- a Department of Biomedical Sciences ; City University of Hong Kong ; Hong Kong , China
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287
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van’t Wout EF, van Schadewijk A, Lomas DA, Stolk J, Marciniak SJ, Hiemstra PS. Function of monocytes and monocyte-derived macrophages in α1-antitrypsin deficiency. Eur Respir J 2014; 45:365-76. [DOI: 10.1183/09031936.00046114] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
α1-antitrypsin deficiency is the most widely recognised genetic disorder causing chronic obstructive pulmonary disease (COPD). Mutant Z α1-antitrypsin expression has previously been linked to intracellular accumulation and polymerisation of this proteinase inhibitor. Subsequently, this has been described to underlie an exaggerated endoplasmic reticulum stress response and enhanced nuclear factor-κB signalling. However, whether monocyte-derived macrophages display the same features remains unknown.Monocytes from homozygous PiZZ α1-antitrypsin deficiency patients and PiMM controls were cultured for 6 days in the presence of granulocyte-macrophage or macrophage colony-stimulating factor to obtain pro- and anti-inflammatory macrophages (mφ-1 and mφ-2, respectively).We first showed that, in contrast to monocytes, pre-stressed mφ-1 and mφ-2 from healthy blood donors display an enhanced endoplasmic reticulum stress response upon a lipopolysaccharide trigger (XBP1 splicing, CHOP, GADD34 and GRP78 mRNA). However, this endoplasmic reticulum stress response did not differ between monocyte-derived macrophages and monocytes from ZZ patients compared to MM controls. Furthermore, these ZZ cells do not secrete higher cytokine levels, and α1-antitrypsin polymers were not detectable by ELISA.These data suggest that monocyte-derived macrophages are not the local source of Z α1-antitrypsin polymers found in the lung and that endoplasmic reticulum stress and pro-inflammatory cytokine release is not altered.
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288
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Abstract
Alpha-1-antitrypsin (α1AT) deficiency is a genetic disorder that manifests as pulmonary emphysema and liver cirrhosis. α1AT deficiency is the most common genetic cause of liver disease in children and also an underappreciated cause of liver disease in adults. The prevalence in the general population in Western Europe is approximately 1 in 2,000. The most common and severe deficiency allele is the Z variant (two alleles mutated). This variant is characterized by the accumulation of Z-α1AT polymers in the endoplasmic reticulum of hepatocytes leading to cell death and to a severe reduction of α1AT in the serum. The latter results in a loss of its antiprotease activity and its ability to protect lung tissue. Thus far, there are only very limited therapeutic options in α1AT deficiency. A more detailed understanding of the biology governing α1AT biogenesis is required in order to identify new pharmacological agents and biomarkers. This review will present current knowledge on α1AT deficiency and focus on recent discoveries and new strategies in the treatment of this disease.
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Affiliation(s)
- Marion Bouchecareilh
- Institut de biochimie et génétique cellulaires, CNRS UMR 5095, université de Bordeaux, 1, rue Camille Saint-Saëns, 33077 Bordeaux, France
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289
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Lu Y, Wang WJ, Song YZ, Liang ZQ. The protective mechanism of schisandrin A in d-galactosamine-induced acute liver injury through activation of autophagy. PHARMACEUTICAL BIOLOGY 2014; 52:1302-1307. [PMID: 24992201 DOI: 10.3109/13880209.2014.890232] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
CONTEXT The principal bioactive lignan of Schisandra chinensis fructus, commonly used for traditional Chinese medicine, is schisandrin A. Schisandrin A has been widely reported as being very effective for the treatment of liver disease. However, the mechanisms of its protective effects in liver remain unclear. OBJECTIVE To explore the hepatoprotective mechanisms of schisandrin A. MATERIALS AND METHODS d-Galactosamine (d-GalN)-induced liver injury in mice was used as a model. Schisandrin A was examined for its protective mechanisms using hematoxylin-eosin (HE) staining, enzyme-linked immunosorbent assay (ELISA), western blotting and real-time PCR (RT-PCR). RESULTS Aspartate amino-transferase (AST) and alanine transaminase (ALT) levels in the schisandrin A group were significantly decreased (p < 0.01) compared with those in the d-GalN-treated group. HE results showed that the pathological changes in hepatic tissue seen in the d-GalN-treated were reduced in the schisandrin A/d-GalN-treated group, with the morphological characteristics being close to those of the control (untreated) group. Western blotting results showed that schisandrin A can activate autophagy flux and inhibit progression of apoptosis. The immune function of the schisandrin A-pretreated group was assayed by flow cytometry. It was found that the mechanism may involve activated autophagy flux, inhibited apoptosis, and improved immunity in response to liver damage. CONCLUSION Our results show that the hepatoprotective mechanisms of schisandrin A may include activation of autophagy flux and inhibition of apoptosis. These results provide pharmacological evidence supporting its future clinical application.
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Affiliation(s)
- Ye Lu
- Department of Pharmacology, College of Pharmaceutical Science, Soochow University , Suzhou , China
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290
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Abstract
Alpha-1 antitrypsin (AAT) deficiency is an under-recognized hereditary disorder associated with the premature onset of chronic obstructive pulmonary disease, liver cirrhosis in children and adults, and less frequently, relapsing panniculitis, systemic vasculitis and other inflammatory, autoimmune and neoplastic diseases. Severe AAT deficiency mainly affects Caucasian individuals and has its highest prevalence (1 : 2000-1 : 5000 individuals) in Northern, Western and Central Europe. In the USA and Canada, the prevalence is 1: 5000-10 000. Prevalence is five times lower in Latin American countries and is rare or nonexistent in African and Asian individuals. The key to successful diagnosis is by measuring serum AAT, followed by the determination of the phenotype or genotype if low concentrations are found. Case detection allows implementation of genetic counselling and, in selected cases, the application of augmentation therapy. Over the past decade, it has been demonstrated that AAT is a broad-spectrum anti-inflammatory, immunomodulatory, anti-infective and tissue-repair molecule. These new capacities are promoting an increasing number of clinical studies, new pharmacological formulations, new patent applications and the search for alternative sources of AAT (including transgenic and recombinant AAT) to meet the expected demand for treating a large number of diseases, inside and outside the context of AAT deficiency.
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Affiliation(s)
- F de Serres
- Center for the Evaluation of Risks to Human Reproduction, National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA
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291
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Haddock CJ, Blomenkamp K, Gautam M, James J, Mielcarska J, Gogol E, Teckman J, Skowyra D. PiZ mouse liver accumulates polyubiquitin conjugates that associate with catalytically active 26S proteasomes. PLoS One 2014; 9:e106371. [PMID: 25210780 PMCID: PMC4161314 DOI: 10.1371/journal.pone.0106371] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 07/29/2014] [Indexed: 11/19/2022] Open
Abstract
Accumulation of aggregation-prone human alpha 1 antitrypsin mutant Z (AT-Z) protein in PiZ mouse liver stimulates features of liver injury typical of human alpha 1 antitrypsin type ZZ deficiency, an autosomal recessive genetic disorder. Ubiquitin-mediated proteolysis by the 26S proteasome counteracts AT-Z accumulation and plays other roles that, when inhibited, could exacerbate the injury. However, it is unknown how the conditions of AT-Z mediated liver injury affect the 26S proteasome. To address this question, we developed a rapid extraction strategy that preserves polyubiquitin conjugates in the presence of catalytically active 26S proteasomes and allows their separation from deposits of insoluble AT-Z. Compared to WT, PiZ extracts had about 4-fold more polyubiquitin conjugates with no apparent change in the levels of the 26S and 20S proteasomes, and unassembled subunits. The polyubiquitin conjugates had similar affinities to ubiquitin-binding domain of Psmd4 and co-purified with similar amounts of catalytically active 26S complexes. These data show that polyubiquitin conjugates were accumulating despite normal recruitment to catalytically active 26S proteasomes that were available in excess, and suggest that a defect at the 26S proteasome other than compromised binding to polyubiquitin chain or peptidase activity played a role in the accumulation. In support of this idea, PiZ extracts were characterized by high molecular weight, reduction-sensitive forms of selected subunits, including ATPase subunits that unfold substrates and regulate access to proteolytic core. Older WT mice acquired similar alterations, implying that they result from common aspects of oxidative stress. The changes were most pronounced on unassembled subunits, but some subunits were altered even in the 26S proteasomes co-purified with polyubiquitin conjugates. Thus, AT-Z protein aggregates indirectly impair degradation of polyubiquitinated proteins at the level of the 26S proteasome, possibly by inducing oxidative stress-mediated modifications that compromise substrate delivery to proteolytic core.
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Affiliation(s)
- Christopher J. Haddock
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Keith Blomenkamp
- Department of Pediatrics, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Madhav Gautam
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Jared James
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Joanna Mielcarska
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Edward Gogol
- School of Biological Sciences, University of Missouri – Kansas City, Kansas City, Missouri, United States of America
| | - Jeffrey Teckman
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Pediatrics, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - Dorota Skowyra
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
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292
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Abstract
From unicellular organisms to humans, cells have evolved elegant systems to facilitate careful folding of proteins and the maintenance of protein homeostasis. Key modulators of protein homeostasis include a large, conserved family of proteins known as molecular chaperones, which augment the folding of nascent polypeptides and temper adverse consequences of cellular stress. However, errors in protein folding can still occur, resulting in the accumulation of misfolded proteins that strain cellular quality-control systems. In some cases, misfolded proteins can be targeted for degradation by the proteasome or via autophagy. Nevertheless, protein misfolding is a feature of many complex, genetically and clinically pleiotropic diseases, including neurodegenerative disorders and cancer. In recent years, substantial progress has been made in unraveling the complexity of protein folding using model systems, and we are now closer to being able to diagnose and treat the growing number of protein-folding diseases. To showcase some of these important recent advances, and also to inspire discussion on approaches to tackle unanswered questions, Disease Models & Mechanisms (DMM) presents a special collection of reviews from researchers at the cutting-edge of the field.
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Affiliation(s)
- Jeffrey L Brodsky
- Department of Biological Sciences, A320 Langley Hall, University of Pittsburgh, Pittsburgh, PA 15260, USA
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293
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Abstract
For a protein to function appropriately, it must first achieve its proper conformation and location within the crowded environment inside the cell. Multiple chaperone systems are required to fold proteins correctly. In addition, degradation pathways participate by destroying improperly folded proteins. The intricacy of this multisystem process provides many opportunities for error. Furthermore, mutations cause misfolded, nonfunctional forms of proteins to accumulate. As a result, many pathological conditions are fundamentally rooted in the protein-folding problem that all cells must solve to maintain their function and integrity. Here, to illustrate the breadth of this phenomenon, we describe five examples of protein-misfolding events that can lead to disease: improper degradation, mislocalization, dominant-negative mutations, structural alterations that establish novel toxic functions, and amyloid accumulation. In each case, we will highlight current therapeutic options for battling such diseases.
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Affiliation(s)
- Julie S Valastyan
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
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294
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Sha H, Sun S, Francisco AB, Ehrhardt N, Xue Z, Liu L, Lawrence P, Mattijssen F, Guber RD, Panhwar MS, Brenna JT, Shi H, Xue B, Kersten S, Bensadoun A, Péterfy M, Long Q, Qi L. The ER-associated degradation adaptor protein Sel1L regulates LPL secretion and lipid metabolism. Cell Metab 2014; 20:458-70. [PMID: 25066055 PMCID: PMC4156539 DOI: 10.1016/j.cmet.2014.06.015] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 03/17/2014] [Accepted: 06/06/2014] [Indexed: 10/25/2022]
Abstract
Sel1L is an essential adaptor protein for the E3 ligase Hrd1 in the endoplasmic reticulum (ER)-associated degradation (ERAD), a universal quality-control system in the cell; but its physiological role remains unclear. Here we show that mice with adipocyte-specific Sel1L deficiency are resistant to diet-induced obesity and exhibit postprandial hypertriglyceridemia. Further analyses reveal that Sel1L is indispensable for the secretion of lipoprotein lipase (LPL), independent of its role in Hrd1-mediated ERAD and ER homeostasis. Sel1L physically interacts with and stabilizes the LPL maturation complex consisting of LPL and lipase maturation factor 1 (LMF1). In the absence of Sel1L, LPL is retained in the ER and forms protein aggregates, which are degraded primarily by autophagy. The Sel1L-mediated control of LPL secretion is also seen in other LPL-expressing cell types including cardiac myocytes and macrophages. Thus, our study reports a role of Sel1L in LPL secretion and systemic lipid metabolism.
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Affiliation(s)
- Haibo Sha
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Shengyi Sun
- Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA
| | - Adam B Francisco
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
| | - Nicole Ehrhardt
- Department of Biomedical Sciences, Medical Genetics Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Zhen Xue
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Lei Liu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Peter Lawrence
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Frits Mattijssen
- Nutrition Metabolism and Genomics Group, Wageningen University, Wageningen 6703HD, the Netherlands
| | - Robert D Guber
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Muhammad S Panhwar
- Weill Cornell Medical College in Qatar, P.O. Box 24144, Education City, Doha, Qatar
| | - J Thomas Brenna
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Hang Shi
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
| | - Sander Kersten
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA; Nutrition Metabolism and Genomics Group, Wageningen University, Wageningen 6703HD, the Netherlands
| | - André Bensadoun
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA
| | - Miklós Péterfy
- Department of Biomedical Sciences, Medical Genetics Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA; Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Qiaoming Long
- Laboratory Animal Research Center, Medical College of Soochow University, Suzhou, Jiangsu 215006, China
| | - Ling Qi
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14853, USA; Graduate Program in Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, NY 14853, USA.
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295
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Ni HM, Woolbright BL, Williams J, Copple B, Cui W, Luyendyk JP, Jaeschke H, Ding WX. Nrf2 promotes the development of fibrosis and tumorigenesis in mice with defective hepatic autophagy. J Hepatol 2014; 61:617-25. [PMID: 24815875 PMCID: PMC4143992 DOI: 10.1016/j.jhep.2014.04.043] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 04/27/2014] [Accepted: 04/29/2014] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Autophagy is an intracellular lysosomal degradation process that plays an important role in regulating normal physiological functions of the liver. The purpose of the present study was to investigate the mechanism(s) by which the loss of hepatic autophagy leads to liver inflammation, fibrosis and tumorigenesis. METHODS Hepatocyte-specific Atg5 knockout mice were generated by crossing Atg5 Flox/Flox mice with albumin Cre mice. These mice were also crossed with Nrf2 knockout mice to generate Atg5 Flox/Flox, Albumin Cre(+)/Nrf2(-/-) double knockout mice. These mice were housed for various time points up to 15 months, and blood and liver tissues were harvested for biochemical and histological analysis. RESULTS Hepatocyte-specific deletion of Atg5 resulted in increased apoptosis, inflammation and fibrosis in the liver. Increased apoptosis in hepatocyte-specific Atg5 knockout mice was likely due to accumulation of aberrant polyubiquitinated proteins (proteotoxicity) and disruption of the homeostasis of pro-and anti-apoptotic proteins. All of these pathological changes started as early as one month and persisted for 12-15 months. At 9-15 months of age, these mice also developed hepatocellular adenomas. Interestingly, deletion of Nrf2 in Atg5 liver-specific knockout mice markedly abolished these pathological changes, indicating a key role for this transcription factor in the mechanism of hepatic pathology. CONCLUSIONS Our results provide genetic evidence that loss of autophagy in hepatocytes causes cell death resulting in liver inflammation, fibrosis and tumorigenesis. We also demonstrate that persistent activation of Nrf2 is critical for liver inflammation, fibrosis and eventual tumorigenesis that occur in mice with defects in hepatocyte autophagy.
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Affiliation(s)
- Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Benjamin L Woolbright
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Jessica Williams
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Bryan Copple
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Wei Cui
- Department of Pathology & Laboratory Medicine, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - James P Luyendyk
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States; Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, MI 48824, United States
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States.
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296
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Mallat A, Lodder J, Teixeira-Clerc F, Moreau R, Codogno P, Lotersztajn S. Autophagy: a multifaceted partner in liver fibrosis. BIOMED RESEARCH INTERNATIONAL 2014; 2014:869390. [PMID: 25254217 PMCID: PMC4164803 DOI: 10.1155/2014/869390] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 07/01/2014] [Indexed: 02/07/2023]
Abstract
Liver fibrosis is a common wound healing response to chronic liver injury of all causes, and its end-stage cirrhosis is responsible for high morbidity and mortality worldwide. Fibrosis results from prolonged parenchymal cell apoptosis and necrosis associated with an inflammatory reaction that leads to recruitment of immune cells, activation and accumulation of fibrogenic cells, and extracellular matrix accumulation. The fibrogenic process is driven by hepatic myofibroblasts, that mainly derive from hepatic stellate cells undergoing a transdifferentiation from a quiescent, lipid-rich into a fibrogenic myofibroblastic phenotype, in response to paracrine/autocrine signals produced by neighbouring inflammatory and parenchymal cells. Autophagy is an important regulator of liver homeostasis under physiological and pathological conditions. This review focuses on recent findings showing that autophagy is a novel, but complex, regulatory pathway in liver fibrosis, with profibrogenic effects relying on its direct contribution to the process of hepatic stellate cell activation, but with antifibrogenic properties via indirect hepatoprotective and anti-inflammatory properties. Therefore, cell-specific delivery of drugs that exploit autophagic pathways is a prerequisite to further consider autophagy as a potential target for antifibrotic therapy.
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Affiliation(s)
- Ariane Mallat
- INSERM U955, 94000 Créteil, France
- Université Paris-Est, Faculté de Médecine, UMR-S955, 94000 Créteil, France
| | - Jasper Lodder
- INSERM U1149, Center for Research on Inflammation, 75018 Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 75018 Paris, France
- Laboratoire d'Excellence Inflamex, 75018 Paris, France
| | - Fatima Teixeira-Clerc
- INSERM U955, 94000 Créteil, France
- Université Paris-Est, Faculté de Médecine, UMR-S955, 94000 Créteil, France
| | - Richard Moreau
- INSERM U1149, Center for Research on Inflammation, 75018 Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 75018 Paris, France
- Laboratoire d'Excellence Inflamex, 75018 Paris, France
- Département Hospitalo-Universitaire (DHU) UNITY, Service d'Hépatologie, Hôpital Beaujon, AP-HP, 92000 Clichy, France
| | - Patrice Codogno
- INSERM U1151-CNRS UMR8223, INEM, 75014 Paris, France
- Université Paris-Descartes, Sorbonne Paris Cité, Site Necker Enfants-Malades, 75015 Paris, France
| | - Sophie Lotersztajn
- INSERM U1149, Center for Research on Inflammation, 75018 Paris, France
- Université Paris Diderot, Sorbonne Paris Cité, Faculté de Médecine, Site Xavier Bichat, 75018 Paris, France
- Laboratoire d'Excellence Inflamex, 75018 Paris, France
- Département Hospitalo-Universitaire (DHU) UNITY, Service d'Hépatologie, Hôpital Beaujon, AP-HP, 92000 Clichy, France
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297
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Skow A, Douglas I, Smeeth L. The association between Parkinson's disease and anti-epilepsy drug carbamazepine: a case-control study using the UK General Practice Research Database. Br J Clin Pharmacol 2014; 76:816-22. [PMID: 23432592 DOI: 10.1111/bcp.12100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Accepted: 02/12/2013] [Indexed: 01/14/2023] Open
Abstract
AIMS To investigate whether the use of carbamazepine is associated with reduced risk of Parkinson's disease. METHODS We conducted a population-based, matched case-control study of patients randomly selected from the UK General Research Practice Database. We identified 8549 patients with Parkinson's disease using diagnosis criteria with a positive predictive value of 90%. These patients were compared with 42, 160 control subjects matched for age, sex and general practice. RESULTS Overall, 3.0% of cases (257 of 8549) had at least one recorded prescription for carbamazepine compared with 2.5% (1050 of 42, 160) of controls. The crude odds ratio for the association between Parkinson's disease and carbamazepine was 1.22 (95% confidence interval 1.06-1.40), but this reduced to 0.93 (95% confidence interval 0.81-1.08, P = 0.34) after adjusting for annual consultation rate. Further adjustment for body mass index, smoking status, alcohol consumption or use of calcium channel blockers did not affect results. There was no evidence that risk decreased with higher doses or longer duration of carbamazepine use. CONCLUSIONS There was little to no evidence that use of carbamazepine is associated with reduced risk of Parkinson's disease. Although the study was underpowered, it does indicate that any effect of carbamazepine is likely to be small.
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Affiliation(s)
- Aine Skow
- Department of Non-Communicable Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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298
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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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299
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Szondy Z, Garabuczi E, Joós G, Tsay GJ, Sarang Z. Impaired clearance of apoptotic cells in chronic inflammatory diseases: therapeutic implications. Front Immunol 2014; 5:354. [PMID: 25136342 PMCID: PMC4117929 DOI: 10.3389/fimmu.2014.00354] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Accepted: 07/09/2014] [Indexed: 12/14/2022] Open
Abstract
In healthy individuals, billions of cells die by apoptosis every day. Removal of the dead cells by phagocytosis (a process called efferocytosis) must be efficient to prevent secondary necrosis and the consequent release of pro-inflammatory cell contents that damages the tissue environment and provokes autoimmunity. In addition, detection and removal of apoptotic cells generally induces an anti-inflammatory response. As a consequence improper clearance of apoptotic cells, being the result of either genetic anomalies and/or a persistent disease state, contributes to the establishment and progression of a number of human chronic inflammatory diseases such as autoimmune and neurological disorders, inflammatory lung diseases, obesity, type 2 diabetes, or atherosclerosis. During the past decade, our knowledge about the mechanism of efferocytosis has significantly increased, providing therapeutic targets through which impaired phagocytosis of apoptotic cells and the consequent inflammation could be influenced in these diseases.
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Affiliation(s)
- Zsuzsa Szondy
- Department of Dental Biochemistry, Faculty of Dentistry, University of Debrecen , Debrecen , Hungary
| | - Eva Garabuczi
- Department of Dental Biochemistry, Faculty of Dentistry, University of Debrecen , Debrecen , Hungary
| | - Gergely Joós
- Department of Dental Biochemistry, Faculty of Dentistry, University of Debrecen , Debrecen , Hungary
| | - Gregory J Tsay
- Department of Internal Medicine, Faculty of Medicine, Chung Shan Medical University Hospital , Taichung , Taiwan
| | - Zsolt Sarang
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen , Debrecen , Hungary
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300
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Turner AM. Alpha-1 antitrypsin deficiency: new developments in augmentation and other therapies. BioDrugs 2014; 27:547-58. [PMID: 23771682 DOI: 10.1007/s40259-013-0042-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alpha 1 antitrypsin deficiency (AATD) is a rare cause of chronic obstructive pulmonary disease. The lung disease is thought to be caused primarily by a lack of effective protection against the harmful effects of neutrophil elastase due to the low AAT levels in the lung. Patients may also develop liver disease due to polymerisation of AAT within hepatocytes. Consequently there has been much research over the years into AAT augmentation therapy in patients with lung disease, initially intravenously, and more recently in inhaled forms. This review article will discuss the role of augmentation therapy in AATD and the current status of recombinant AAT. The potential for other therapeutic strategies, such as blocking polymer formation, enhancing autophagy, gene therapy and stem cell-based treatment, will also be discussed more briefly.
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Affiliation(s)
- Alice M Turner
- QEHB Research Labs, University of Birmingham, Mindelsohn Way, Birmingham, B15 2WB, UK,
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