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Verkade HJ, Felzen A, Keitel V, Thompson R, Gonzales E, Strnad P, Kamath B, van Mil S. EASL Clinical Practice Guidelines on genetic cholestatic liver diseases. J Hepatol 2024; 81:303-325. [PMID: 38851996 DOI: 10.1016/j.jhep.2024.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 04/05/2024] [Indexed: 06/10/2024]
Abstract
Genetic cholestatic liver diseases are caused by (often rare) mutations in a multitude of different genes. While these diseases differ in pathobiology, clinical presentation and prognosis, they do have several commonalities due to their cholestatic nature. These Clinical Practice Guidelines (CPGs) offer a general approach to genetic testing and management of cholestatic pruritus, while exploring diagnostic and treatment approaches for a subset of genetic cholestatic liver diseases in depth. An expert panel appointed by the European Association for the Study of the Liver has created recommendations regarding diagnosis and treatment, based on the best evidence currently available in the fields of paediatric and adult hepatology, as well as genetics. The management of these diseases generally takes place in a tertiary referral centre, in order to provide up-to-date approaches and expertise. These CPGs are intended to support hepatologists (for paediatric and adult patients), residents and other healthcare professionals involved in the management of these patients with concrete recommendations based on currently available evidence or, if not available, on expert opinion.
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Zhao P, Wang C, Sun S, Wang X, Balch WE. Tracing genetic diversity captures the molecular basis of misfolding disease. Nat Commun 2024; 15:3333. [PMID: 38637533 PMCID: PMC11026414 DOI: 10.1038/s41467-024-47520-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Genetic variation in human populations can result in the misfolding and aggregation of proteins, giving rise to systemic and neurodegenerative diseases that require management by proteostasis. Here, we define the role of GRP94, the endoplasmic reticulum Hsp90 chaperone paralog, in managing alpha-1-antitrypsin deficiency on a residue-by-residue basis using Gaussian process regression-based machine learning to profile the spatial covariance relationships that dictate protein folding arising from sequence variants in the population. Covariance analysis suggests a role for the ATPase activity of GRP94 in controlling the N- to C-terminal cooperative folding of alpha-1-antitrypsin responsible for the correction of liver aggregation and lung-disease phenotypes of alpha-1-antitrypsin deficiency. Gaussian process-based spatial covariance profiling provides a standard model built on covariant principles to evaluate the role of proteostasis components in guiding information flow from genome to proteome in response to genetic variation, potentially allowing us to intervene in the onset and progression of complex multi-system human diseases.
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Affiliation(s)
- Pei Zhao
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, China.
| | - Shuhong Sun
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- Department of Nutrition and Food Hygiene, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, China
- Institute for Brain Tumors, Collaborative Innovation Center for Cancer Personalized Medicine, and Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Xi Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA.
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3
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Sun S, Wang C, Zhao P, Kline GM, Grandjean JMD, Jiang X, Labaudiniere R, Wiseman RL, Kelly JW, Balch WE. Capturing the conversion of the pathogenic alpha-1-antitrypsin fold by ATF6 enhanced proteostasis. Cell Chem Biol 2023; 30:22-42.e5. [PMID: 36630963 PMCID: PMC9930901 DOI: 10.1016/j.chembiol.2022.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/07/2022] [Accepted: 12/19/2022] [Indexed: 01/12/2023]
Abstract
Genetic variation in alpha-1 antitrypsin (AAT) causes AAT deficiency (AATD) through liver aggregation-associated gain-of-toxic pathology and/or insufficient AAT activity in the lung manifesting as chronic obstructive pulmonary disease (COPD). Here, we utilize 71 AATD-associated variants as input through Gaussian process (GP)-based machine learning to study the correction of AAT folding and function at a residue-by-residue level by pharmacological activation of the ATF6 arm of the unfolded protein response (UPR). We show that ATF6 activators increase AAT neutrophil elastase (NE) inhibitory activity, while reducing polymer accumulation for the majority of AATD variants, including the prominent Z variant. GP-based profiling of the residue-by-residue response to ATF6 activators captures an unexpected role of the "gate" area in managing AAT-specific activity. Our work establishes a new spatial covariant (SCV) understanding of the convertible state of the protein fold in response to genetic perturbation and active environmental management by proteostasis enhancement for precision medicine.
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Affiliation(s)
- Shuhong Sun
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Chao Wang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Pei Zhao
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Gabe M Kline
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | | | - Xin Jiang
- Protego Biopharma, 10945 Vista Sorrento Parkway, San Diego, CA, USA
| | | | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jeffery W Kelly
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - William E Balch
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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Chen G, Wei T, Ju F, Li H. Protein quality control and aggregation in the endoplasmic reticulum: From basic to bedside. Front Cell Dev Biol 2023; 11:1156152. [PMID: 37152279 PMCID: PMC10154544 DOI: 10.3389/fcell.2023.1156152] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
Endoplasmic reticulum (ER) is the largest membrane-bound compartment in all cells and functions as a key regulator in protein biosynthesis, lipid metabolism, and calcium balance. Mammalian endoplasmic reticulum has evolved with an orchestrated protein quality control system to handle defective proteins and ensure endoplasmic reticulum homeostasis. Nevertheless, the accumulation and aggregation of misfolded proteins in the endoplasmic reticulum may occur during pathological conditions. The inability of endoplasmic reticulum quality control system to clear faulty proteins and aggregates from the endoplasmic reticulum results in the development of many human disorders. The efforts to comprehensively understand endoplasmic reticulum quality control network and protein aggregation will benefit the diagnostics and therapeutics of endoplasmic reticulum storage diseases. Herein, we overview recent advances in mammalian endoplasmic reticulum protein quality control system, describe protein phase transition model, and summarize the approaches to monitor protein aggregation. Moreover, we discuss the therapeutic applications of enhancing endoplasmic reticulum protein quality control pathways in endoplasmic reticulum storage diseases.
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Affiliation(s)
- Guofang Chen
- Shanghai Key Laboratory of Maternal Fetal Medicine, Clinical and Translational Research Center of Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Tingyi Wei
- Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Institute of Precision Medicine, Shanghai, China
| | - Furong Ju
- Ming Wai Lau Centre for Reparative Medicine, Karolinska Institutet, Sha Tin, Hong kong SAR, China
| | - Haisen Li
- School of Life Sciences, Fudan University, Shanghai, China
- AoBio Medical, Shanghai, China
- *Correspondence: Haisen Li,
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5
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Tacchi F, Orozco-Aguilar J, Valero-Breton M, Cabello-Verrugio C. Bile Acids Alter the Autophagy and Mitogenesis in Skeletal Muscle Cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1408:183-199. [PMID: 37093428 DOI: 10.1007/978-3-031-26163-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
Muscle atrophy decreases muscle mass with the subsequent loss of muscle function. Among the mechanisms that trigger sarcopenia is mitochondrial dysfunction. Mitochondria, whose primary function is to produce ATP, are dynamic organelles that present the process of formation (mitogenesis) and elimination (mitophagy). Failure of any of these processes contributes to mitochondrial malfunction. Mitogenesis is mainly controlled by Peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α), a transcriptional coactivator that regulates the expression of TFAM, which participates in mitogenesis. Mitophagy is a process of selective autophagy. Autophagy corresponds to a degradative pathway of protein complexes and organelles. Liver disease caused sarcopenia and increased bile acids in the blood. We demonstrated that the treatment with cholic (CA) or deoxycholic (DCA) bile acids generates mitochondrial dysfunction and loss of biomass. This work assessed whether CA and DCA alter autophagy and mitogenesis. For this, western blot evaluated the autophagy process by determining the protein levels of the LC3II/LC3I ratio. In addition, we assessed mitogenesis using a luciferase-coupled plasmid reporter for the PGC-1α promoter and the protein levels of TFAM by western blot. Our results indicate that treatment with CA or DCA induces autophagy, represented by an increase in the LC3II/LC3I ratio. In addition, a decreased autophagic flux was observed. On the other hand, when treated with CA or DCA, a decrease in the activity of the PGC-1α promoter was observed. However, the levels of TFAM increased in myotubes incubated with CA and DCA. Our results demonstrate that CA and DCA modulate autophagy ad mitogenesis in C2C12 myotubes.
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Affiliation(s)
- Franco Tacchi
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, 8370146, Chile
- Millennium Institute on Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
| | - Josué Orozco-Aguilar
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, 8370146, Chile
- Millennium Institute on Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
- Laboratorio de Ensayos Biológicos (LEBi), Universidad de Costa Rica, San José, Costa Rica
- Facultad de Farmacia, Universidad de Costa Rica, San José, Costa Rica
| | - Mayalen Valero-Breton
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, 8370146, Chile
- Millennium Institute on Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
| | - Claudio Cabello-Verrugio
- Laboratory of Muscle Pathology, Fragility and Aging, Faculty of Life Sciences, Universidad Andres Bello, Santiago, 8370146, Chile.
- Millennium Institute on Immunology and Immunotherapy, Faculty of Life Sciences, Universidad Andres Bello, Santiago, Chile.
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile.
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Duwaerts CC, Maiers JL. ER Disposal Pathways in Chronic Liver Disease: Protective, Pathogenic, and Potential Therapeutic Targets. Front Mol Biosci 2022; 8:804097. [PMID: 35174209 PMCID: PMC8841999 DOI: 10.3389/fmolb.2021.804097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
The endoplasmic reticulum is a central player in liver pathophysiology. Chronic injury to the ER through increased lipid content, alcohol metabolism, or accumulation of misfolded proteins causes ER stress, dysregulated hepatocyte function, inflammation, and worsened disease pathogenesis. A key adaptation of the ER to resolve stress is the removal of excess or misfolded proteins. Degradation of intra-luminal or ER membrane proteins occurs through distinct mechanisms that include ER-associated Degradation (ERAD) and ER-to-lysosome-associated degradation (ERLAD), which includes macro-ER-phagy, micro-ER-phagy, and Atg8/LC-3-dependent vesicular delivery. All three of these processes are critical for removing misfolded or unfolded protein aggregates, and re-establishing ER homeostasis following expansion/stress, which is critical for liver function and adaptation to injury. Despite playing a key role in resolving ER stress, the contribution of these degradative processes to liver physiology and pathophysiology is understudied. Analysis of publicly available datasets from diseased livers revealed that numerous genes involved in ER-related degradative pathways are dysregulated; however, their roles and regulation in disease progression are not well defined. Here we discuss the dynamic regulation of ER-related protein disposal pathways in chronic liver disease and cell-type specific roles, as well as potentially targetable mechanisms for treatment of chronic liver disease.
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Affiliation(s)
- Caroline C. Duwaerts
- Department of Medicine, University of California, San Francisco, San Francisco, CA, United States
| | - Jessica L. Maiers
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, United States
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Li H, Sun S. Protein Aggregation in the ER: Calm behind the Storm. Cells 2021; 10:cells10123337. [PMID: 34943844 PMCID: PMC8699410 DOI: 10.3390/cells10123337] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 02/06/2023] Open
Abstract
As one of the largest organelles in eukaryotic cells, the endoplasmic reticulum (ER) plays a vital role in the synthesis, folding, and assembly of secretory and membrane proteins. To maintain its homeostasis, the ER is equipped with an elaborate network of protein folding chaperones and multiple quality control pathways whose cooperative actions safeguard the fidelity of protein biogenesis. However, due to genetic abnormalities, the error-prone nature of protein folding and assembly, and/or defects or limited capacities of the protein quality control systems, nascent proteins may become misfolded and fail to exit the ER. If not cleared efficiently, the progressive accumulation of misfolded proteins within the ER may result in the formation of toxic protein aggregates, leading to the so-called “ER storage diseases”. In this review, we first summarize our current understanding of the protein folding and quality control networks in the ER, including chaperones, unfolded protein response (UPR), ER-associated protein degradation (ERAD), and ER-selective autophagy (ER-phagy). We then survey recent research progress on a few ER storage diseases, with a focus on the role of ER quality control in the disease etiology, followed by a discussion on outstanding questions and emerging concepts in the field.
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Affiliation(s)
- Haisen Li
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
| | - Shengyi Sun
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA;
- Department of Biochemistry, Microbiology and Immunology, Wayne State University School of Medicine, Detroit, MI 48201, USA
- Correspondence:
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Involvement of Autophagy in Ageing and Chronic Cholestatic Diseases. Cells 2021; 10:cells10102772. [PMID: 34685751 PMCID: PMC8534511 DOI: 10.3390/cells10102772] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/05/2021] [Accepted: 10/13/2021] [Indexed: 01/18/2023] Open
Abstract
Autophagy is a “housekeeping” lysosomal degradation process involved in numerous physiological and pathological processes in all eukaryotic cells. The dysregulation of hepatic autophagy has been described in several conditions, from obesity to diabetes and cholestatic disease. We review the role of autophagy, focusing on age-related cholestatic diseases, and discuss its therapeutic potential and the molecular targets identified to date. The accumulation of toxic BAs is the main cause of cell damage in cholestasis patients. BAs and their receptor, FXR, have been implicated in the regulation of hepatic autophagy. The mechanisms by which cholestasis induces liver damage include mitochondrial dysfunction, oxidative stress and ER stress, which lead to cell death and ultimately to liver fibrosis as a compensatory mechanism to reduce the damage. The stimulation of autophagy seems to ameliorate the liver damage. Autophagic activity decreases with age in several species, whereas its basic extends lifespan in animals, suggesting that it is one of the convergent mechanisms of several longevity pathways. No strategies aimed at inducing autophagy have yet been tested in cholestasis patients. However, its stimulation can be viewed as a novel therapeutic strategy that may reduce ageing-dependent liver deterioration and also mitigate hepatic steatosis.
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Patel D, Teckman J. Liver disease with unknown etiology - have you ruled out alpha-1 antitrypsin deficiency? Ther Adv Chronic Dis 2021; 12_suppl:2040622321995684. [PMID: 34408828 PMCID: PMC8367207 DOI: 10.1177/2040622321995684] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/12/2021] [Indexed: 01/13/2023] Open
Abstract
Although a less well-known consequence of alpha-1 antitrypsin deficiency (AATD) liver disease is the second leading cause of death among patients with the condition. The alpha-1 antitrypsin (AAT) protein is produced by hepatocytes within the liver, which retain pathological variants of AAT instead of secreting the proteinase inhibitor into the systemic circulation. This intracellular retention is caused by inefficient folding and polymerization of mutant AAT and the accumulation of these AAT aggregates leads to diverse manifestations of liver disease, which can present differently in both children and adults. The progression from hepatocyte apoptosis to liver inflammation, fibrosis and cirrhosis, and liver failure is still not fully understood, but in older patients, liver disease can surpass lung disease as the principal cause of death. Liver function tests (LFTs) can measure plasma levels of liver enzymes to assess liver function but require careful interpretation. Non-invasive tests are being developed that can detect early liver disease, but liver biopsy is still the gold standard for assessing liver fibrosis once abnormal LFTs have been detected in a patient. Currently, there is no licensed treatment for AATD-related liver disease (intravenous AAT therapy is not indicated for this purpose), but liver transplantation is associated with positive outcomes and may even slow emphysema progression. Therefore, new strategies are being developed to address treatment of AATD-related liver disease, such as accelerating degradation of mutant AAT and assisting hepatocytes in the folding and secretion of mutant AAT, but these approaches remain at early stages of development.
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Affiliation(s)
- Dhiren Patel
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, St Louis University School of Medicine, St Louis, MO, USA
| | - Jeffrey Teckman
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, St Louis University School of Medicine, St Louis, MO, USA
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10
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Marek G, Collinsworth A, Liu C, Brantly M, Clark V. Quantitative measurement of the histological features of alpha-1 antitrypsin deficiency-associated liver disease in biopsy specimens. PLoS One 2021; 16:e0256117. [PMID: 34398915 PMCID: PMC8366994 DOI: 10.1371/journal.pone.0256117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 07/31/2021] [Indexed: 11/27/2022] Open
Abstract
Background Pathological mutations in Alpha-1 Antitrypsin (AAT) protein cause retention of toxic polymers in the hepatocyte endoplasmic reticulum. The risk for cirrhosis in AAT deficiency is likely directly related to retention of these polymers within the liver. Polymers are classically identified on liver biopsy as inclusion bodies by periodic acid schiff staining after diastase treatment and immunohistochemistry. However, characterization of the polymer burden within a biopsy sample is limited to a semi-quantitative scale as described by a pathologist. Better methods to quantify polymer are needed to advance our understanding of pathogenesis of disease. Therefore, we developed a method to quantify polymer aggregation from standard histologic specimens. In addition, we sought to understand the relationship of polymer burden and other histologic findings to the presence of liver fibrosis. Methods Liver samples from a well-categorized AATD cohort were used to develop histo-morphometric tools to measure protein aggregation. Results Whole-slide morphometry reliably quantifies aggregates in AATD individuals. Despite very low levels of inclusions present (0–0.41%), accumulation of globules is not linear and is associated with higher fibrosis stages. Immunohistochemistry demonstrates that fibrosis is associated with polymer accumulation and not total AAT. A proportion of patients were found to be “heavy accumulators” with a polymer burden above the upper 25% of normal distribution. Males had significantly more liver inclusions and polymer than females. These measurements also highlight interrelated phenotypes of hepatocellular degeneration and autophagy in AATD liver disease. Conclusion Quantitative inclusion analysis measures AAT accumulation in liver biopsy specimens. Quantification of polymer may identify individuals at risk for progressive disease and candidates for therapeutic interventions. Furthermore, these methods may be useful for evaluating efficacy of drugs targeting accumulation of AAT.
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Affiliation(s)
- George Marek
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
| | - Amy Collinsworth
- Advanced Pathology Solutions, Little Rock, Arkansas, United States of America
| | - Chen Liu
- Department of Pathology, Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Mark Brantly
- Division of Pulmonary, Critical Care, and Sleep Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Virginia Clark
- Division of Gastroenterology, Hepatology, and Nutrition, University of Florida, Gainesville, Florida, United States of America
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The Autophagy Pathway: A Critical Route in the Disposal of Alpha 1-Antitrypsin Aggregates That Holds Many Mysteries. Int J Mol Sci 2021; 22:ijms22041875. [PMID: 33668611 PMCID: PMC7917825 DOI: 10.3390/ijms22041875] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/10/2021] [Accepted: 02/11/2021] [Indexed: 12/23/2022] Open
Abstract
The maintenance of proteome homeostasis, or proteostasis, is crucial for preserving cellular functions and for cellular adaptation to environmental challenges and changes in physiological conditions. The capacity of cells to maintain proteostasis requires precise control and coordination of protein synthesis, folding, conformational maintenance, and clearance. Thus, protein degradation by the ubiquitin–proteasome system (UPS) or the autophagy–lysosomal system plays an essential role in cellular functions. However, failure of the UPS or the autophagic process can lead to the development of various diseases (aging-associated diseases, cancer), thus both these pathways have become attractive targets in the treatment of protein conformational diseases, such as alpha 1-antitrypsin deficiency (AATD). The Z alpha 1-antitrypsin (Z-AAT) misfolded variant of the serine protease alpha 1-antitrypsin (AAT) is caused by a structural change that predisposes it to protein aggregation and dramatic accumulation in the form of inclusion bodies within liver hepatocytes. This can lead to clinically significant liver disease requiring liver transplantation in childhood or adulthood. Treatment of mice with autophagy enhancers was found to reduce hepatic Z-AAT aggregate levels and protect them from AATD hepatotoxicity. To date, liver transplantation is the only curative therapeutic option for patients with AATD-mediated liver disease. Therefore, the development and discovery of new therapeutic approaches to delay or overcome disease progression is a top priority. Herein, we review AATD-mediated liver disease and the overall process of autophagy. We highlight the role of this system in the regulation of Z-variant degradation and its implication in AATD-medicated liver disease, including some open questions that remain challenges in the field and require further elucidation. Finally, we discuss how manipulation of autophagy could provide multiple routes of therapeutic benefit in AATD-mediated liver disease.
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12
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Kouroumalis E, Voumvouraki A, Augoustaki A, Samonakis DN. Autophagy in liver diseases. World J Hepatol 2021; 13:6-65. [PMID: 33584986 PMCID: PMC7856864 DOI: 10.4254/wjh.v13.i1.6] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 12/10/2020] [Accepted: 12/26/2020] [Indexed: 02/06/2023] Open
Abstract
Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.
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Affiliation(s)
- Elias Kouroumalis
- Liver Research Laboratory, University of Crete Medical School, Heraklion 71110, Greece
| | - Argryro Voumvouraki
- 1 Department of Internal Medicine, AHEPA University Hospital, Thessaloniki 54636, Greece
| | - Aikaterini Augoustaki
- Department of Gastroenterology and Hepatology, University Hospital of Crete, Heraklion 71110, Greece
| | - Dimitrios N Samonakis
- Department of Gastroenterology and Hepatology, University Hospital of Crete, Heraklion 71110, Greece.
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13
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Panzitt K, Fickert P, Wagner M. Regulation of autophagy by bile acids and in cholestasis - CholestoPHAGY or CholeSTOPagy. Biochim Biophys Acta Mol Basis Dis 2020; 1867:166017. [PMID: 33242590 DOI: 10.1016/j.bbadis.2020.166017] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/13/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022]
Abstract
Autophagy is a lysosomal degradation pathway in which the cell self-digests its own components to provide nutrients in harsh environmental conditions. It also represents an opportunity to rid the cell of superfluous and damaged organelles, misfolded proteins or invaded microorganisms. Liver autophagy contributes to basic hepatic functions such as lipid, glycogen and protein turnover. Deregulated hepatic autophagy has been linked to many liver diseases including alpha-1-antitrypsin deficiency, alcoholic and non-alcoholic fatty liver diseases, hepatitis B and C infections, liver fibrosis as well as liver cancer. Recently, bile acids and the bile acid receptor FXR have been implicated in the regulation of hepatic autophagy, which implies a role of autophagy also for cholestatic liver diseases. This review summarizes the current evidence of bile acid mediated effects on autophagy and how this affects cholestatic liver diseases. Although detailed studies are lacking, we suggest a concept that the activity of autophagy in cholestasis depends on the disease stage, where autophagy may be induced at early stages ("cholestophagy") but may be impaired in prolonged cholestatic states ("cholestopagy").
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Affiliation(s)
- Katrin Panzitt
- Research Unit for Translational Nuclear Receptor Research, Division of Gastroenterology and Hepatology, Medical University of Graz, Graz, Austria
| | - Peter Fickert
- Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Medical University of Graz, Graz, Austria
| | - Martin Wagner
- Research Unit for Translational Nuclear Receptor Research, Division of Gastroenterology and Hepatology, Medical University of Graz, Graz, Austria.
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Narayanan P, Mistry PK. Update on Alpha-1 Antitrypsin Deficiency in Liver Disease. Clin Liver Dis (Hoboken) 2020; 15:228-235. [PMID: 32617155 PMCID: PMC7326637 DOI: 10.1002/cld.896] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 10/23/2019] [Indexed: 02/04/2023] Open
Affiliation(s)
| | - Pramod K. Mistry
- Department of Digestive DiseasesYale–New Haven HospitalNew HavenCT
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15
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Li Y, Liu R, Wu J, Li X. Self-eating: friend or foe? The emerging role of autophagy in fibrotic diseases. Am J Cancer Res 2020; 10:7993-8017. [PMID: 32724454 PMCID: PMC7381749 DOI: 10.7150/thno.47826] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/16/2020] [Indexed: 01/18/2023] Open
Abstract
Fibrosis occurs in most human organs including the liver, lung, heart and kidney, and is crucial for the progression of most chronic diseases. As an indispensable catabolic process for intracellular quality control and homeostasis, autophagy occurs in most mammalian cells and is implicated in many biological processes including fibrogenesis. Although advances have been made in understanding autophagy process, the potential role of autophagy in fibrotic diseases remains controversial and has recently attracted a great deal of attention. In the current review, we summarize the commonalities of autophagy affecting different types of fibrosis in different organs, including the liver, lung, heart, and kidney as well as in cystic fibrosis, systematically outline the contradictory results and highlight the distinct role of autophagy during the various stages of fibrosis. In summary, the exact role autophagy plays in fibrogenesis depends on specific cell types and different stimuli, and identifying and evaluating the pathogenic contribution of autophagy in fibrogenesis will promote the discovery of novel therapeutic strategies for the clinical management of these fibrotic diseases.
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16
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Kriegermeier A, Green R. Pediatric Cholestatic Liver Disease: Review of Bile Acid Metabolism and Discussion of Current and Emerging Therapies. Front Med (Lausanne) 2020; 7:149. [PMID: 32432119 PMCID: PMC7214672 DOI: 10.3389/fmed.2020.00149] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 04/06/2020] [Indexed: 02/06/2023] Open
Abstract
Cholestatic liver diseases are a significant cause of morbidity and mortality and the leading indication for pediatric liver transplant. These include diseases such as biliary atresia, Alagille syndrome, progressive intrahepatic cholestasis entities, ductal plate abnormalities including Caroli syndrome and congenital hepatic fibrosis, primary sclerosing cholangitis, bile acid synthesis defects, and certain metabolic disease. Medical management of these patients typically includes supportive care for complications of chronic cholestasis including malnutrition, pruritus, and portal hypertension. However, there are limited effective interventions to prevent progressive liver damage in these diseases, leaving clinicians to ultimately rely on liver transplantation in many cases. Agents such as ursodeoxycholic acid, bile acid sequestrants, and rifampicin have been mainstays of treatment for years with the understanding that they may decrease or alter the composition of the bile acid pool, though clinical response to these medications is frequently insufficient and their effects on disease progression remain limited. Recently, animal and human studies have identified potential new therapeutic targets which may disrupt the enterohepatic circulation of bile acids, alter the expression of bile acid transporters or decrease the production of bile acids. In this article, we will review bile formation, bile acid signaling, and the relevance for current and newer therapies for pediatric cholestasis. We will also highlight further areas of potential targets for medical intervention for pediatric cholestatic liver diseases.
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Affiliation(s)
- Alyssa Kriegermeier
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Feinberg School of Medicine, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Chicago, IL, United States
| | - Richard Green
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
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17
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Wang C, Zhao P, Sun S, Teckman J, Balch WE. Leveraging Population Genomics for Individualized Correction of the Hallmarks of Alpha-1 Antitrypsin Deficiency. CHRONIC OBSTRUCTIVE PULMONARY DISEASES-JOURNAL OF THE COPD FOUNDATION 2020; 7:224-246. [PMID: 32726074 DOI: 10.15326/jcopdf.7.3.2019.0167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Deep medicine is rapidly moving towards a high-definition approach for therapeutic management of the patient as an individual given the rapid progress of genome sequencing technologies and machine learning algorithms. While considered a monogenic disease, alpha-1 antitrypsin (AAT) deficiency (AATD) patients present with complex and variable phenotypes we refer to as the "hallmarks of AATD" that involve distinct molecular mechanisms in the liver, plasma and lung tissues, likely due to both coding and non-coding variation as well as genetic and environmental modifiers in different individuals. Herein, we briefly review the current therapeutic strategies for the management of AATD. To embrace genetic diversity in the management of AATD, we provide an overview of the disease phenotypes of AATD patients harboring different AAT variants. Linking genotypic diversity to phenotypic diversity illustrates the potential for sequence-specific regions of AAT protein fold design to play very different roles during nascent synthesis in the liver and/or function in post-liver plasma and lung environments. We illustrate how to manage diversity with recently developed machine learning (ML) approaches that bridge sequence-to-function-to-structure knowledge gaps based on the principle of spatial covariance (SCV). SCV relationships provide a deep understanding of the genotype to phenotype transformation initiated by AAT variation in the population to address the role of genetic and environmental modifiers in the individual. Embracing the complexity of AATD in the population is critical for risk management and therapeutic intervention to generate a high definition medicine approach for the patient.
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Affiliation(s)
- Chao Wang
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Pei Zhao
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Shuhong Sun
- Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Jeffrey Teckman
- Pediatrics and Biochemistry, Saint Louis University, and Cardinal Glennon Children's Medical Center, St. Louis, Missouri
| | - William E Balch
- Department of Molecular Medicine, Scripps Research, La Jolla, California
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18
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Sobani ZA, Paniz GR, Wong M, McCarthy DM. Don't Miss the BoAAT: Correctly Diagnosing Acute-on-Chronic Liver Disease. Dig Dis Sci 2019; 64:2780-2783. [PMID: 31456092 DOI: 10.1007/s10620-019-05816-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Zain A Sobani
- Division of Gastroenterology, University of New Mexico School of Medicine, Albuquerque, NM, USA. .,Division of Gastroenterology and Hepatology, 1 University of New Mexico, MSC10-5550, Albuquerque, NM, 87131, USA.
| | - Graziella R Paniz
- Department of Medicine, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Morgan Wong
- Division of Gastroenterology, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Denis M McCarthy
- Division of Gastroenterology, University of New Mexico School of Medicine, Albuquerque, NM, USA
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19
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Fromme M, Oliverius M, Strnad P. DEFI-ALFA: The French key to the alpha1 mystery? Liver Int 2019; 39:1019-1021. [PMID: 31127687 DOI: 10.1111/liv.14064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 01/26/2019] [Accepted: 01/29/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Malin Fromme
- Coordinating Center for Alpha1-Antitrypsin Deficiency-Related Liver Disease of the European Reference Network (ERN) "Rare Liver" and the European Association for the Study of the Liver (EASL) Registry Group "Alpha1-Liver", Aachen, Germany.,Medical Clinic III, Metabolic diseases and Intensive Care, University Hospital RWTH, Gastroenterology, Aachen, Germany
| | - Martin Oliverius
- Department of General Surgery, 3rd Faculty of Medicine, Charles University and Hospital Kralovske Vinohrady, Prague, Czech Republic.,Center for Cardiovascular and Transplant Surgery, Brno, Czech Republic
| | - Pavel Strnad
- Coordinating Center for Alpha1-Antitrypsin Deficiency-Related Liver Disease of the European Reference Network (ERN) "Rare Liver" and the European Association for the Study of the Liver (EASL) Registry Group "Alpha1-Liver", Aachen, Germany.,Medical Clinic III, Metabolic diseases and Intensive Care, University Hospital RWTH, Gastroenterology, Aachen, Germany
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20
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Abstract
Endoplasmic reticulum (ER) stress occurs when ER homeostasis is perturbed with accumulation of unfolded/misfolded protein or calcium depletion. The unfolded protein response (UPR), comprising of inositol-requiring enzyme 1α (IRE1α), PKR-like ER kinase (PERK) and activating transcription factor 6 (ATF6) signaling pathways, is a protective cellular response activated by ER stress. However, UPR activation can also induce cell death upon persistent ER stress. The liver is susceptible to ER stress given its synthetic and other biological functions. Numerous studies from human liver samples and animal disease models have indicated a crucial role of ER stress and UPR signaling pathways in the pathogenesis of liver diseases, including non-alcoholic fatty liver disease, alcoholic liver disease, alpha-1 antitrypsin deficiency, cholestatic liver disease, drug-induced liver injury, ischemia/reperfusion injury, viral hepatitis and hepatocellular carcinoma. Extensive investigations have demonstrated the potential underlying mechanisms of the induction of ER stress and the contribution of UPR pathways during the development of the diseases. Moreover ER stress and the UPR proteins and genes have become emerging therapeutic targets to treat liver diseases.
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Affiliation(s)
- Xiaoying Liu
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Tarry Building 15-709, 303 East Superior Street, Chicago, IL 60611, Northwestern University Feinberg School of Medicine, Chicago, IL, USA, Corresponding author: Xiaoying-liu@northwestern
| | - Richard M. Green
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, Tarry Building 15-709, 303 East Superior Street, Chicago, IL 60611, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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21
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NorUDCA promotes degradation of α1-antitrypsin mutant Z protein by inducing autophagy through AMPK/ULK1 pathway. PLoS One 2018; 13:e0200897. [PMID: 30067827 PMCID: PMC6070232 DOI: 10.1371/journal.pone.0200897] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 07/05/2018] [Indexed: 02/07/2023] Open
Abstract
Alpha-1 Antitrypsin (α1AT) Deficiency is a genetic disease in which accumulation of α1AT mutant Z (α1ATZ) protein in the ER of hepatocytes causes chronic liver injury, liver fibrosis, and hepatocellular carcinoma. No effective medical therapy is currently available for the disease. We previously found that norUDCA improves the α1AT deficiency associated liver disease by promoting autophagic degradation of α1ATZ protein in liver in a mouse model of the disease. The current study unravels the novel underlying cellular mechanism by which norUDCA modulates autophagy. HTOZ cells, modified from HeLa Tet-Off cells by transfection with the resulting pTRE1-ATZ plasmid and expressing mutant Z proteins, were studied in these experiments. The role of norUDCA in inducing autophagy, autophagy-mediated degradation of α1ATZ and the role of AMPK in norUDCA-induced autophagy were examined in the current report. NorUDCA promoted disposal of α1ATZ via autophagy-mediated degradation of α1ATZ in HTOZ cells. Activation of AMPK was required for norUDCA-induced autophagy and α1ATZ degradation. Moreover, mTOR/ULK1 was involved in norUDCA-induced AMPK activation and autophagy in HTOZ cells. Our results provide novel mechanistic insights into the therapeutic action of norUDCA in promoting the clearance of α1ATZ in vitro and suggest a novel therapeutic approach for the treatment of α1ATZ deficiency disease and its associated liver diseases.
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22
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Wang Y, Ding WX, Li T. Cholesterol and bile acid-mediated regulation of autophagy in fatty liver diseases and atherosclerosis. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:726-733. [PMID: 29653253 PMCID: PMC6037329 DOI: 10.1016/j.bbalip.2018.04.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/22/2018] [Accepted: 04/08/2018] [Indexed: 12/19/2022]
Abstract
Liver is the major organ that regulates whole body cholesterol metabolism. Disrupted hepatic cholesterol homeostasis contributes to the pathogenesis of nonalcoholic steatohepatitis, dyslipidemia, atherosclerosis, and cardiovascular diseases. Hepatic bile acid synthesis is the major catabolic mechanism for cholesterol elimination from the body. Furthermore, bile acids are signaling molecules that regulate liver metabolism and inflammation. Autophagy is a highly-conserved lysosomal degradation mechanism, which plays an essential role in maintaining cellular integrity and energy homeostasis. In this review, we discuss emerging evidence linking hepatic cholesterol and bile acid metabolism to cellular autophagy activity in hepatocytes and macrophages, and how these interactions may be implicated in the pathogenesis and treatment of fatty liver disease and atherosclerosis.
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Affiliation(s)
- Yifeng Wang
- 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
| | - Tiangang Li
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, United States.
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23
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Mitchell EL, Khan Z. Liver Disease in Alpha-1 Antitrypsin Deficiency: Current Approaches and Future Directions. CURRENT PATHOBIOLOGY REPORTS 2017; 5:243-252. [PMID: 29399420 PMCID: PMC5780543 DOI: 10.1007/s40139-017-0147-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Purpose of Review The aim of the study is to review the liver disease caused by alpha-1 antitrypsin deficiency (A1ATD), including pathogenesis, epidemiology, diagnostic testing, and recent therapeutic developments. Recent Findings Therapeutic approaches target several intracellular pathways to reduce the cytotoxic effects of the misfolded mutant globular protein (ATZ) on the hepatocyte. These include promoting ATZ transport out of the endoplasmic reticulum (ER), enhancing ATZ degradation, and preventing ATZ globule-aggregation. Summary A1ATD is the leading genetic cause of liver disease among children. It is a protein-folding disorder in which toxic insoluble ATZ proteins aggregate in the ER of hepatocytes leading to inflammation, fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma. The absence of the normal A1AT serum protein also predisposes patients to pan lobar emphysema as adults. At this time, the only approved therapy for A1ATD-associated liver disease is orthotopic liver transplantation, which is curative. However, there has been significant recent progress in the development of small molecule therapies with potential both to preserve the native liver and prevent hepatotoxicity.
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Affiliation(s)
- Ellen L Mitchell
- 1Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Faculty Pavilion 6th Fl, Pittsburgh, PA 15224-1334 USA.,2Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Zahida Khan
- 1Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Pittsburgh of UPMC, 4401 Penn Avenue, Faculty Pavilion 6th Fl, Pittsburgh, PA 15224-1334 USA.,2Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA USA.,3Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA.,4McGowan Institute for Regenerative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA USA.,5Pittsburgh Liver Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
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24
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Autophagy in Hepatocytes in Infants With Alpha-1 ATD and Different Liver Disease Outcomes: A Retrospective Analysis. J Pediatr Gastroenterol Nutr 2017; 64:876-882. [PMID: 28045767 DOI: 10.1097/mpg.0000000000001507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES It is unclear whether a distinct activity of pathways removing the antitrypsin (AT) protein in Alpha-1-Antitrypsin Deficiency (α1ATD) are associated with an unfavorable predisposition to liver disease in the future. The aim of this study was to determine whether liverspecific activity of AT protein disposal occurs at infancy in α1ATD with PiZZ phenotype (ATZ). METHODS Liver samples of 17 infants with unfavorable ATZ outcome (Group I, n = 8, median age = 0.35 year) and good outcome (Group II, n = 9, 0.17 year), and 9 with biliary atresia (BA, median age = 0.17 year) as control, were enrolled. For each subject were investigated autophagy activity by mRNA, protein expression (Calnexin, Beclin-1, p62, and Parkin), and hepatocyte ultrastructure with morphometric analyses. RESULTS No significant differences in gene expression in the liver of infants were found between the 2 ATZ groups. Although a correlation between patients' age and protein expression was observed, the ATZ groups differed Parkin immunohistochemical expression. Moreover, the hepatocytes in ATZ infants with unfavorable outcome were characterized by low Parkin expression and the presence of isolated mitophagosoms and numerous enlarged mitochondria. The mentioned findings differed in patients with BA. CONCLUSIONS Thus, mentioned specific features occurring at infancy may suggest association with poor liver outcome. Parkin low expression could have a potential for disease prognosis and treatment; however, further studies in a greater number of patients are needed.
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25
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Khan Z, Yokota S, Ono Y, Bell AW, Oertel M, Stolz DB, Michalopoulos GK. Bile Duct Ligation Induces ATZ Globule Clearance in a Mouse Model of α-1 Antitrypsin Deficiency. Gene Expr 2017; 17:115-127. [PMID: 27938510 PMCID: PMC5296240 DOI: 10.3727/105221616x692991] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
α-1 Antitrypsin deficiency (A1ATD) can progress to cirrhosis and hepatocellular carcinoma; however, not all patients are susceptible to severe liver disease. In A1ATD, a toxic gain-of-function mutation generates insoluble ATZ "globules" in hepatocytes, overwhelming protein clearance mechanisms. The relationship between bile acids and hepatocytic autophagy is less clear but may involve altered gene expression pathways. Based on previous findings that bile duct ligation (BDL) induces autophagy, we hypothesized that retained bile acids may have hepatoprotective effects in PiZZ transgenic mice, which model A1ATD. We performed BDL and partial BDL (pBDL) in PiZZ mice, followed by analysis of liver tissues. PiZZ liver subjected to BDL showed up to 50% clearance of ATZ globules, with increased expression of autophagy proteins. Analysis of transcription factors revealed significant changes. Surprisingly nuclear TFEB, a master regulator of autophagy, remained unchanged. pBDL confirmed that ATZ globule clearance was induced by localized stimuli rather than diet or systemic effects. Several genes involved in bile metabolism were overexpressed in globule-devoid hepatocytes, compared to globule-containing cells. Retained bile acids led to a dramatic reduction of ATZ globules, with enhanced hepatocyte regeneration and autophagy. These findings support investigation of synthetic bile acids as potential autophagy-enhancing agents.
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Affiliation(s)
- Zahida Khan
- *Department of Pediatrics, Children’s Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
- †Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- ‡McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Shinichiro Yokota
- §Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- ¶Department of Surgery, Jichi Medical University, Shimotsuke, Japan
| | - Yoshihiro Ono
- §Department of Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Aaron W. Bell
- †Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Michael Oertel
- †Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Donna B. Stolz
- ‡McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- #Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - George K. Michalopoulos
- †Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- ‡McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
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