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Buniatian GH, Schwinghammer U, Tremmel R, Cynis H, Weiss TS, Weiskirchen R, Lauschke VM, Youhanna S, Ramos I, Valcarcel M, Seferyan T, Rahfeld J, Rieckmann V, Klein K, Buadze M, Weber V, Kolak V, Gebhardt R, Friedman SL, Müller UC, Schwab M, Danielyan L. Consequences of Amyloid-β Deficiency for the Liver. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307734. [PMID: 38430535 PMCID: PMC11095235 DOI: 10.1002/advs.202307734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 01/27/2024] [Indexed: 03/04/2024]
Abstract
The hepatic content of amyloid beta (Aβ) decreases drastically in human and rodent cirrhosis highlighting the importance of understanding the consequences of Aβ deficiency in the liver. This is especially relevant in view of recent advances in anti-Aβ therapies for Alzheimer's disease (AD). Here, it is shown that partial hepatic loss of Aβ in transgenic AD mice immunized with Aβ antibody 3D6 and its absence in amyloid precursor protein (APP) knockout mice (APP-KO), as well as in human liver spheroids with APP knockdown upregulates classical hallmarks of fibrosis, smooth muscle alpha-actin, and collagen type I. Aβ absence in APP-KO and deficiency in immunized mice lead to strong activation of transforming growth factor-β (TGFβ), alpha secretases, NOTCH pathway, inflammation, decreased permeability of liver sinusoids, and epithelial-mesenchymal transition. Inversely, increased systemic and intrahepatic levels of Aβ42 in transgenic AD mice and neprilysin inhibitor LBQ657-treated wild-type mice protect the liver against carbon tetrachloride (CCl4)-induced injury. Transcriptomic analysis of CCl4-treated transgenic AD mouse livers uncovers the regulatory effects of Aβ42 on mitochondrial function, lipid metabolism, and its onco-suppressive effects accompanied by reduced synthesis of extracellular matrix proteins. Combined, these data reveal Aβ as an indispensable regulator of cell-cell interactions in healthy liver and a powerful protector against liver fibrosis.
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Affiliation(s)
- Gayane Hrachia Buniatian
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
| | - Ute Schwinghammer
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
| | - Roman Tremmel
- Dr. Margarete Fischer‐Bosch Institute of Clinical PharmacologyAuerbachstr. 11270376StuttgartGermany
- University of Tuebingen72074TuebingenGermany
| | - Holger Cynis
- Department of Drug Design and Target ValidationFraunhofer Institute for Cell Therapy and ImmunologyWeinbergweg 2206120Halle (Saale)Germany
- Junior Research Group, Immunomodulation in Pathophysiological ProcessesFaculty of MedicineMartin‐Luther‐University Halle‐WittenbergWeinbergweg 2206120Halle (Saale)Germany
| | - Thomas S. Weiss
- Children's University Hospital (KUNO)University Hospital RegensburgFranz‐Josef‐Strauss‐Allee 1193053RegensburgGermany
| | - Ralf Weiskirchen
- Institute of Molecular PathobiochemistryExperimental Gene Therapy and Clinical ChemistryRWTH University Hospital AachenPauwelsstr. 3052074AachenGermany
| | - Volker M. Lauschke
- Dr. Margarete Fischer‐Bosch Institute of Clinical PharmacologyAuerbachstr. 11270376StuttgartGermany
- University of Tuebingen72074TuebingenGermany
- Department of Physiology and Pharmacology Karolinska InstituteStockholm171 77Sweden
| | - Sonia Youhanna
- Department of Physiology and Pharmacology Karolinska InstituteStockholm171 77Sweden
| | - Isbaal Ramos
- Innovative Technologies in Biological Systems SL (INNOPROT)BizkaiaDerio48160Spain
| | - Maria Valcarcel
- Innovative Technologies in Biological Systems SL (INNOPROT)BizkaiaDerio48160Spain
| | - Torgom Seferyan
- H. Buniatian Institute of BiochemistryNational Academy of Sciences of the Republic of Armenia (NAS RA)5/1 Paruir Sevak St.Yerevan0014Armenia
| | - Jens‐Ulrich Rahfeld
- Department of Drug Design and Target ValidationFraunhofer Institute for Cell Therapy and ImmunologyWeinbergweg 2206120Halle (Saale)Germany
| | - Vera Rieckmann
- Department of Drug Design and Target ValidationFraunhofer Institute for Cell Therapy and ImmunologyWeinbergweg 2206120Halle (Saale)Germany
| | - Kathrin Klein
- Dr. Margarete Fischer‐Bosch Institute of Clinical PharmacologyAuerbachstr. 11270376StuttgartGermany
- University of Tuebingen72074TuebingenGermany
| | - Marine Buadze
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
| | - Victoria Weber
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
| | - Valentina Kolak
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
| | - Rolf Gebhardt
- Rudolf‐Schönheimer Institute of BiochemistryFaculty of MedicineUniversity of LeipzigJohannisstraße 3004103LeipzigGermany
| | - Scott L. Friedman
- Division of Liver DiseasesIcahn School of Medicine at Mount Sinai1425 Madison AveNew YorkNY10029USA
| | - Ulrike C. Müller
- Institute for Pharmacy and Molecular Biotechnology IPMBDepartment of Functional GenomicsUniversity of HeidelbergIm Neuenheimer Feld 36469120HeidelbergGermany
| | - Matthias Schwab
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
- Dr. Margarete Fischer‐Bosch Institute of Clinical PharmacologyAuerbachstr. 11270376StuttgartGermany
- Departments of Biochemistry and Clinical Pharmacologyand Neuroscience LaboratoryYerevan State Medical University2‐ Koryun StYerevan0025Armenia
- Cluster of Excellence iFIT (EXC2180) “Image‐guided and Functionally Instructed Tumor Therapies”University of Tübingen72076TübingenGermany
| | - Lusine Danielyan
- Department of Clinical PharmacologyUniversity Hospital of TuebingenAuf der Morgenstelle 872076TuebingenGermany
- Departments of Biochemistry and Clinical Pharmacologyand Neuroscience LaboratoryYerevan State Medical University2‐ Koryun StYerevan0025Armenia
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Mladenić K, Lenartić M, Marinović S, Polić B, Wensveen FM. The "Domino effect" in MASLD: The inflammatory cascade of steatohepatitis. Eur J Immunol 2024; 54:e2149641. [PMID: 38314819 DOI: 10.1002/eji.202149641] [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: 08/24/2023] [Revised: 01/17/2024] [Accepted: 01/17/2024] [Indexed: 02/07/2024]
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) is an increasingly common complication of obesity, affecting over a quarter of the global adult population. A key event in the pathophysiology of MASLD is the development of metabolic-associated steatohepatitis (MASH), which greatly increases the chances of developing cirrhosis and hepatocellular carcinoma. The underlying cause of MASH is multifactorial, but accumulating evidence indicates that the inflammatory process in the hepatic microenvironment typically follows a pattern that can be roughly divided into three stages: (1) Detection of hepatocyte stress by tissue-resident immune cells including γδ T cells and CD4-CD8- double-negative T cells, followed by their secretion of pro-inflammatory mediators, most notably IL-17A. (2) Recruitment of pro-inflammatory cells, mostly of the myeloid lineage, and initiation of inflammation through secretion of effector-type cytokines such as TNF, TGF-β, and IL-1β. (3) Escalation of the inflammatory response by recruitment of lymphocytes including Th17, CD8 T, and B cells leading to chronic inflammation, hepatic stellate cell activation, and fibrosis. Here we will discuss these three stages and how they are consecutively linked like falling domino tiles to the pathophysiology of MASH. Moreover, we will highlight the clinical potential of inflammation as a biomarker and therapeutic target for the treatment of MASLD.
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Affiliation(s)
- Karlo Mladenić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Maja Lenartić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Sonja Marinović
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
- Division of Molecular Medicine, Laboratory for Personalized Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Bojan Polić
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Felix M Wensveen
- Department of Histology and Embryology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Zhang Y, Zhang WQ, Liu XY, Zhang Q, Mao T, Li XY. Immune cells and immune cell-targeted therapy in chronic pancreatitis. Front Oncol 2023; 13:1151103. [PMID: 36969002 PMCID: PMC10034053 DOI: 10.3389/fonc.2023.1151103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/27/2023] [Indexed: 03/11/2023] Open
Abstract
In recent years, studies have attempted to understand the immune cells and mechanisms underlying the pathogenesis of chronic pancreatitis (CP) by constructing a model of CP. Based on these studies, the innate immune response is a key factor in disease pathogenesis and inflammation severity. Novel mechanisms of crosstalk between immune and non-immune pancreatic cells, such as pancreatic stellate cells (PSC), have also been explored. Immune cells, immune responses, and signaling pathways in CP are important factors in the development and progression of pancreatitis. Based on these mechanisms, targeted therapy may provide a feasible scheme to stop or reverse the progression of the disease in the future and provide a new direction for the treatment of CP. This review summarizes the recent advances in research on immune mechanisms in CP and the new advances in treatment based on these mechanisms.
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Wei Y, Bingyu W, Lei Y, Xingxing Y. The antifibrotic role of natural killer cells in liver fibrosis. Exp Biol Med (Maywood) 2022; 247:1235-1243. [PMID: 35475367 PMCID: PMC9379607 DOI: 10.1177/15353702221092672] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Liver fibrosis is the common pathological change of chronic liver diseases characterized by increased deposition of extracellular matrix and reduced matrix degradation. In response to liver injury caused by a variety of pathogenic agents, such as virus and alcohol, hepatic stellate cells (HSCs) are differentiated into myofibroblast-like cells and produce excessive collagens, thus resulting in fibrogenesis. Natural killer (NK) cells are the essential innate immune cells in the liver and generally control fibrosis by killing activated HSCs. This review briefly describes the fibrogenesis process and the phenotypic features of hepatic NK cells. Besides, it focuses on the antifibrotic mechanisms of NK cells and explores the potential of activating NK cells as a therapeutic strategy for the disease.
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Affiliation(s)
- Yuan Wei
- Department of Hepatology, The First Affiliated Hospital of Hunan University of Traditional Chinese Medicine, Changsha 410000, China
| | - Wang Bingyu
- Department of Gastroenterology, Heilongjiang Academy of Traditional Chinese Medicine, Harbin 150001, China
| | - Yang Lei
- Department of Gastroenterology, Heilongjiang Academy of Traditional Chinese Medicine, Harbin 150001, China
| | - Yuan Xingxing
- Department of Gastroenterology, Heilongjiang Academy of Traditional Chinese Medicine, Harbin 150001, China,Yuan Xingxing.
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Zhang Y, Wu Y, Shen W, Wang B, Yuan X. Crosstalk between NK cells and hepatic stellate cells in liver fibrosis (Review). Mol Med Rep 2022; 25:208. [PMID: 35506449 PMCID: PMC9133963 DOI: 10.3892/mmr.2022.12724] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 04/19/2022] [Indexed: 01/18/2023] Open
Abstract
Liver fibrosis is a common pathological process of chronic liver diseases, including viral hepatitis and alcoholic liver disease, and ultimately progresses to irreversible cirrhosis and cancer. Hepatic stellate cells (HSCs) are activated to produce amounts of collagens in response to liver injury, thus triggering the initiation and progression of fibrogenesis. Natural killer (NK) cells serve as the essential component of hepatic innate immunity and are considered to alleviate fibrosis by killing activated HSCs. Current antifibrotic interventions have improved fibrosis, but fail to halt its progression in the advanced stage. Clarifying the interaction between NK cells and HSCs will provide clues to the pathogenesis and potential therapies for advanced liver fibrosis.
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Affiliation(s)
- Yang Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang 150001, P.R. China
| | - Yuan Wu
- The Graduate School, Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang 150001, P.R. China
| | - Wenjuan Shen
- Department of Gynaecology, The First Affiliated Hospital of Heilongjiang University of Traditional Chinese Medicine, Harbin, Heilongjiang 150001, P.R. China
| | - Bingyu Wang
- Department of Gastroenterology, Heilongjiang Academy of Traditional Chinese Medicine, Harbin, Heilongjiang 150001, P.R. China
| | - Xingxing Yuan
- Department of Gastroenterology, Heilongjiang Academy of Traditional Chinese Medicine, Harbin, Heilongjiang 150001, P.R. China
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Salvati A, Poelstra K. Drug Targeting and Nanomedicine: Lessons Learned from Liver Targeting and Opportunities for Drug Innovation. Pharmaceutics 2022; 14:217. [PMID: 35057111 PMCID: PMC8777931 DOI: 10.3390/pharmaceutics14010217] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 02/08/2023] Open
Abstract
Drug targeting and nanomedicine are different strategies for improving the delivery of drugs to their target. Several antibodies, immuno-drug conjugates and nanomedicines are already approved and used in clinics, demonstrating the potential of such approaches, including the recent examples of the DNA- and RNA-based vaccines against COVID-19 infections. Nevertheless, targeting remains a major challenge in drug delivery and different aspects of how these objects are processed at organism and cell level still remain unclear, hampering the further development of efficient targeted drugs. In this review, we compare properties and advantages of smaller targeted drug constructs on the one hand, and larger nanomedicines carrying higher drug payload on the other hand. With examples from ongoing research in our Department and experiences from drug delivery to liver fibrosis, we illustrate opportunities in drug targeting and nanomedicine and current challenges that the field needs to address in order to further improve their success.
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Affiliation(s)
- Anna Salvati
- Correspondence: (A.S.); (K.P.); Tel.: +31-503639831 (A.S.); +31-503633287 (K.P.)
| | - Klaas Poelstra
- Correspondence: (A.S.); (K.P.); Tel.: +31-503639831 (A.S.); +31-503633287 (K.P.)
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7
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Carter JK, Friedman SL. Hepatic Stellate Cell-Immune Interactions in NASH. Front Endocrinol (Lausanne) 2022; 13:867940. [PMID: 35757404 PMCID: PMC9218059 DOI: 10.3389/fendo.2022.867940] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 04/29/2022] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is the dominant cause of liver disease worldwide. Nonalcoholic steatohepatitis (NASH), a more aggressive presentation of NAFLD, is characterized by severe hepatocellular injury, inflammation, and fibrosis. Chronic inflammation and heightened immune cell activity have emerged as hallmark features of NASH and key drivers of fibrosis through the activation of hepatic stellate cells (HSCs). Recent advances in our understanding of the molecular and cellular pathways in NASH have highlighted extensive crosstalk between HSCs and hepatic immune populations that strongly influences disease activity. Here, we review these findings, emphasizing the roles of HSCs in liver immunity and inflammation, key cell-cell interactions, and exciting areas for future investigation.
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Affiliation(s)
- James K Carter
- Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Medical Scientist Training Program, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Scott L Friedman
- Division of Liver Diseases, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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8
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Sánchez PS, Rigual MDM, Djouder N. Inflammatory and Non-Inflammatory Mechanisms Controlling Cirrhosis Development. Cancers (Basel) 2021; 13:cancers13205045. [PMID: 34680192 PMCID: PMC8534267 DOI: 10.3390/cancers13205045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/01/2021] [Accepted: 10/03/2021] [Indexed: 12/28/2022] Open
Abstract
Simple Summary The liver is continuously exposed to several harmful factors, subsequently activating sophisticated mechanisms set-up in order to repair and regenerate the damaged liver and hence to prevent its failure. When the injury becomes chronic, the regenerative response becomes perpetual and goes awry, leading to cirrhosis with a fatal liver dysfunction. Cirrhosis is a well-known risk factor for hepatocellular carcinoma (HCC), the most common, usually lethal, human primary liver neoplasm with very limited therapeutic options. Considering the pivotal role of immune factors in the development of cirrhosis, here we review and discuss the inflammatory pathways and components implicated in the development of cirrhosis. A better understanding of these circuits would help the design of novel strategies to prevent and treat cirrhosis and HCC, two lethal diseases. Abstract Because the liver is considered to be one of the most important metabolic organs in the body, it is continuously exposed to damaging environmental agents. Upon damage, several complex cellular and molecular mechanisms in charge of liver recovery and regeneration are activated to prevent the failure of the organ. When liver injury becomes chronic, the regenerative response goes awry and impairs the liver function, consequently leading to cirrhosis, a liver disorder that can cause patient death. Cirrhosis has a disrupted liver architecture and zonation, along with the presence of fibrosis and parenchymal nodules, known as regenerative nodules (RNs). Inflammatory cues contribute to the cirrhotic process in response to chronic damaging agents. Cirrhosis can progress to HCC, the most common and one of the most lethal liver cancers with unmet medical needs. Considering the essential role of inflammatory pathways in the development of cirrhosis, further understanding of the relationship between immune cells and the activation of RNs and fibrosis would guide the design of innovative therapeutic strategies to ameliorate the survival of cirrhotic and HCC patients. In this review, we will summarize the inflammatory mechanisms implicated in the development of cirrhosis.
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Affiliation(s)
| | | | - Nabil Djouder
- Correspondence: ; Tel.: +34-3-491-732-8000 (ext. 3830); Fax: +34-3-491-224-6914
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Cross-talk between hepatic stellate cells and T lymphocytes in liver fibrosis. Hepatobiliary Pancreat Dis Int 2021; 20:207-214. [PMID: 33972160 DOI: 10.1016/j.hbpd.2021.04.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 04/21/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Fibrosis results from inflammation and healing following injury. The imbalance between extracellular matrix (ECM) secretion and degradation leads to the ECM accumulation and liver fibrosis. This process is regulated by immune cells. T lymphocytes, including alpha beta (αβ) T cells, which have adaptive immune functions, and gamma delta (γδ) T cells, which have innate immune functions, are considered regulators of liver fibrosis. This review aimed to present the current understanding of the cross-talk between T lymphocytes and hepatic stellate cells (HSCs), which are the key cells in liver fibrosis. DATA SOURCES The keywords "liver fibrosis", "immune", and "T cells" were used to retrieve articles published in PubMed database before January 31, 2020. RESULTS The ratio of CD8+ (suppressor) T cells to CD4+ (helper) T cells is significantly higher in the liver than in the peripheral blood. T cells secrete a series of cytokines and chemokines to regulate the inflammation in the liver and the activation of HSCs to influence the course of liver fibrosis. In addition, HSCs also regulate the differentiation and proliferation of T cells. CONCLUSIONS The cross-talk between T cells and HSCs regulates liver fibrosis progression. The elucidation of this communication process will help us to understand the pathological process of liver fibrosis.
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10
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NK cells in liver homeostasis and viral hepatitis. SCIENCE CHINA-LIFE SCIENCES 2018; 61:1477-1485. [PMID: 30421296 DOI: 10.1007/s11427-018-9407-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022]
Abstract
As an important member of the innate immune system, natural killer (NK) cells are well known for their rapid and efficient immune responses against infectious agents and tumors. NK cells are widely distributed throughout the body and are particularly enriched within the liver, where they display unique phenotypic and functional properties, playing important roles in various liver diseases. Herein, we present an overview of liver NK cell properties with regard to phenotype, function, and subset composition at steady state, and we also summarize the complex reciprocal interactions between liver NK cells and other cell types within the local environment of the liver. We also provide an overview of recent advances demonstrating the roles of NK cells in viral hepatitis, including a discussion of NK cell altered states and their beneficial versus harmful effects during hepatitis B virus and hepatitis C virus infection.
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11
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Feng R, Yuan X, Shao C, Ding H, Liebe R, Weng HL. Are we any closer to treating liver fibrosis (and if no, why not)? J Dig Dis 2018; 19:118-126. [PMID: 29389083 DOI: 10.1111/1751-2980.12584] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/26/2018] [Indexed: 12/11/2022]
Abstract
This review provides a personal view on anti-fibrosis therapy in the liver. The worst clinical consequence of liver fibrosis is the development of liver cirrhosis and portal hypertension. Etiology is a decisive factor which determines patterns of fibrous septa and subsequent vascular remodeling, which is essential for the development of portal hypertension. Removing or controlling the disease-causing agent, i.e. anti-viral treatment for hepatitis, is the essential first step for treating chronic liver diseases and can reverse fibrosis in some settings. However, removing etiology is not always sufficient to prevent fibrosis from progressing towards cirrhosis and portal hypertension. In liver diseases such as severe alcoholic hepatitis and massive parenchymal loss, the formation of vascular anastomoses between portal to central veins based on bridging fibrosis results in cirrhosis and portal hypertension. For these patients, anti-fibrotic treatment is crucial and urgent. Unfortunately, a lack of understanding how fibrosis contributes to vascular remodeling caused by and combined with a lack of suitable experimental models that recapitulate human liver diseases, has hampered the development of successful anti-fibrotic drugs for clinical use to date.
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Affiliation(s)
- Rilu Feng
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Xiaodong Yuan
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Chen Shao
- Department of Pathology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Huiguo Ding
- Department of Gastroenterology and Hepatology, Beijing You'an Hospital, Affiliated with Capital Medical University, Beijing, China
| | - Roman Liebe
- Department of Medicine II, Saarland University Medical Center, Homburg/Saar, Germany
| | - Hong-Lei Weng
- Department of Medicine II, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Kumar S, Wang J, Shanmukhappa SK, Gandhi CR. Toll-Like Receptor 4-Independent Carbon Tetrachloride-Induced Fibrosis and Lipopolysaccharide-Induced Acute Liver Injury in Mice: Role of Hepatic Stellate Cells. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1356-1367. [PMID: 28412299 PMCID: PMC5455062 DOI: 10.1016/j.ajpath.2017.01.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 01/30/2017] [Indexed: 12/29/2022]
Abstract
Gram-negative bacterial endotoxin lipopolysaccharide (LPS) is implicated in acute and chronic liver injury; its effects are mediated predominantly via the membrane receptor Toll-like receptor 4 (TLR4). However, TLR4-independent effects of LPS may play important role in hepatic pathophysiology. We investigated carbon tetrachloride (CCl4)-induced fibrosis and LPS-induced acute liver injury in wild-type (WT) and B6.B10ScN-Tlr4lps-del/JthJ [TLR4-knockout (KO)] mice. Effects of LPS on fibrogenic hepatic stellate cells (HSCs) from WT and TLR4-KO mice were assessed in vitro. CCl4 produced similar fibrosis and necroinflammation and increased the mRNA and protein expression of cytokines and chemokines in WT and TLR4-KO mice. However, circulating LPS concentration did not increase in CCl4-treated mice. Interestingly, LPS down-modulated α-smooth muscle actin (activated HSC marker) and collagen 1 in both WT and TLR4-KO HSCs. LPS induced similar activation of NF-κB, and stimulated the expression of cytokines and chemokines in WT and TLR4-KO HSCs. Finally, LPS caused similar inflammation and injury in previously untreated WT and TLR4-KO mice. The results provide evidence of the TLR4/LPS-independent mechanisms of liver fibrosis and also indicate that TLR4 is not entirely critical to LPS-induced acute liver injury. The results further indicate that LPS signaling in activated HSCs might be a mechanism of limiting liver fibrosis.
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Affiliation(s)
- Sudhir Kumar
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Cincinnati VA Medical Center, Cincinnati, Ohio; Department of Surgery, University of Cincinnati, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio
| | - Shiva Kumar Shanmukhappa
- Department of Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Chandrashekhar R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Cincinnati VA Medical Center, Cincinnati, Ohio; Department of Surgery, University of Cincinnati, Cincinnati, Ohio.
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The stellate cell system (vitamin A-storing cell system). Anat Sci Int 2017; 92:387-455. [PMID: 28299597 DOI: 10.1007/s12565-017-0395-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/15/2017] [Indexed: 01/18/2023]
Abstract
Past, present, and future research into hepatic stellate cells (HSCs, also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, or Ito cells) are summarized and discussed in this review. Kupffer discovered black-stained cells in the liver using the gold chloride method and named them stellate cells (Sternzellen in German) in 1876. Wake rediscovered the cells in 1971 using the same gold chloride method and various modern histological techniques including electron microscopy. Between their discovery and rediscovery, HSCs disappeared from the research history. Their identification, the establishment of cell isolation and culture methods, and the development of cellular and molecular biological techniques promoted HSC research after their rediscovery. In mammals, HSCs exist in the space between liver parenchymal cells (PCs) or hepatocytes and liver sinusoidal endothelial cells (LSECs) of the hepatic lobule, and store 50-80% of all vitamin A in the body as retinyl ester in lipid droplets in the cytoplasm. SCs also exist in extrahepatic organs such as pancreas, lung, and kidney. Hepatic (HSCs) and extrahepatic stellate cells (EHSCs) form the stellate cell (SC) system or SC family; the main storage site of vitamin A in the body is HSCs in the liver. In pathological conditions such as liver fibrosis, HSCs lose vitamin A, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan, glycosaminoglycan, and adhesive glycoproteins. The morphology of these cells also changes from the star-shaped HSCs to that of fibroblasts or myofibroblasts.
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Fasbender F, Widera A, Hengstler JG, Watzl C. Natural Killer Cells and Liver Fibrosis. Front Immunol 2016; 7:19. [PMID: 26858722 PMCID: PMC4731511 DOI: 10.3389/fimmu.2016.00019] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/15/2016] [Indexed: 12/16/2022] Open
Abstract
In the 40 years since the discovery of natural killer (NK) cells, it has been well established that these innate lymphocytes are important for early and effective immune responses against transformed cells and infections with different pathogens. In addition to these classical functions of NK cells, we now know that they are part of a larger family of innate lymphoid cells and that they can even mediate memory-like responses. Additionally, tissue-resident NK cells with distinct phenotypical and functional characteristics have been identified. Here, we focus on the phenotype of different NK cell subpopulations that can be found in the liver and summarize the current knowledge about the functional role of these cells with a special emphasis on liver fibrosis. NK cell cytotoxicity can contribute to liver damage in different forms of liver disease. However, NK cells can limit liver fibrosis by killing hepatic stellate cell-derived myofibroblasts, which play a key role in this pathogenic process. Therefore, liver NK cells need to be tightly regulated in order to balance these beneficial and pathological effects.
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Affiliation(s)
- Frank Fasbender
- Department for Immunology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technische Universität Dortmund , Dortmund , Germany
| | - Agata Widera
- Department for Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technische Universität Dortmund , Dortmund , Germany
| | - Jan G Hengstler
- Department for Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technische Universität Dortmund , Dortmund , Germany
| | - Carsten Watzl
- Department for Immunology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Technische Universität Dortmund , Dortmund , Germany
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15
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Abstract
Myofibroblasts are activated in response to tissue injury with the primary task to repair lost or damaged extracellular matrix. Enhanced collagen secretion and subsequent contraction - scarring - are part of the normal wound healing response and crucial to restore tissue integrity. Due to myofibroblasts ability to repair but not regenerate, accumulation of scar tissue is always associated with reduced organ performance. This is a fair price to pay by the body for not falling apart. Whereas myofibroblasts typically vanish after successful repair, dysregulation of the normal repair process can lead to persistent myofibroblast activation, for instance by chronic inflammation or mechanical stress in the tissue. Excessive repair leads to the accumulation of stiff collagenous ECM contractures - fibrosis - with dramatic consequences for organ function. The clinical need to terminate detrimental myofibroblast activities has stimulated researchers to answer a number of essential questions: where do myofibroblasts come from, what are the factors leading to their activation, how do we discriminate myofibroblasts from other cells, what is the molecular basis for their contractile activity, and how can we stop or at least control them? This article reviews the current state of the myofibroblast literature by emphasizing their role in ocular repair and fibrosis. It appears that although the eye is quite an extraordinary organ, ocular myofibroblasts behave or misbehave just like their siblings in other organs.
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Affiliation(s)
- Boris Hinz
- Laboratory of Tissue Repair and Regeneration, Matrix Dynamics Group, Faculty of Dentistry, University of Toronto, 150 College Street, FitzGerald Building, Room 234, Toronto, M5S 3E2 Ontario, Canada.
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16
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Seki E, Schwabe RF. Hepatic inflammation and fibrosis: functional links and key pathways. Hepatology 2015; 61:1066-79. [PMID: 25066777 PMCID: PMC4306641 DOI: 10.1002/hep.27332] [Citation(s) in RCA: 657] [Impact Index Per Article: 73.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 07/16/2014] [Indexed: 02/06/2023]
Abstract
Inflammation is one of the most characteristic features of chronic liver disease of viral, alcoholic, fatty, and autoimmune origin. Inflammation is typically present in all disease stages and associated with the development of fibrosis, cirrhosis, and hepatocellular carcinoma. In the past decade, numerous studies have contributed to improved understanding of the links between hepatic inflammation and fibrosis. Here, we review mechanisms that link inflammation with the development of liver fibrosis, focusing on the role of inflammatory mediators in hepatic stellate cell (HSC) activation and HSC survival during fibrogenesis and fibrosis regression. We will summarize the contributions of different inflammatory cells, including hepatic macrophages, T and B lymphocytes, natural killer cells and platelets, as well as key effectors, such as cytokines, chemokines, and damage-associated molecular patterns. Furthermore, we will discuss the relevance of inflammatory signaling pathways for clinical liver disease and for the development of antifibrogenic strategies.
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Affiliation(s)
- Ekihiro Seki
- Department of Medicine, University of California, San Diego, School
of Medicine, La Jolla, CA 92093, USA,Surgery, University of California, San Diego, School of Medicine, La
Jolla, CA 92093, USA
| | - Robert F. Schwabe
- Department of Medicine, Columbia University, College of Physicians
and Surgeons, New York, NY 10032, USA,Institute of Human Nutrition, Columbia University, College of
Physicians and Surgeons, New York, NY 10032, USA
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17
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Weiskirchen R, Tacke F. Cellular and molecular functions of hepatic stellate cells in inflammatory responses and liver immunology. Hepatobiliary Surg Nutr 2015; 3:344-63. [PMID: 25568859 DOI: 10.3978/j.issn.2304-3881.2014.11.03] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 10/17/2014] [Indexed: 12/11/2022]
Abstract
The liver is a central immunological organ. Liver resident macrophages, Kupffer cells (KC), but also sinusoidal endothelial cells, dendritic cells (DC) and other immune cells are involved in balancing immunity and tolerance against pathogens, commensals or food antigens. Hepatic stellate cells (HSCs) have been primarily characterized as the main effector cells in liver fibrosis, due to their capacity to transdifferentiate into collagen-producing myofibroblasts (MFB). More recent studies elucidated the fundamental role of HSC in liver immunology. HSC are not only the major storage site for dietary vitamin A (Vit A) (retinol, retinoic acid), which is essential for proper function of the immune system. This pericyte further represents a versatile source of many soluble immunological active factors including cytokines [e.g., interleukin 17 (IL-17)] and chemokines [C-C motif chemokine (ligand) 2 (CCL2)], may act as an antigen presenting cell (APC), and has autophagy activity. Additionally, it responds to many immunological triggers via toll-like receptors (TLR) (e.g., TLR4, TLR9) and transduces signals through pathways and mediators traditionally found in immune cells, including the Hedgehog (Hh) pathway or inflammasome activation. Overall, HSC promote rather immune-suppressive responses in homeostasis, like induction of regulatory T cells (Treg), T cell apoptosis (via B7-H1, PDL-1) or inhibition of cytotoxic CD8 T cells. In conditions of liver injury, HSC are important sensors of altered tissue integrity and initiators of innate immune cell activation. Vice versa, several immune cell subtypes interact directly or via soluble mediators with HSC. Such interactions include the mutual activation of HSC (towards MFB) and macrophages or pro-apoptotic signals from natural killer (NK), natural killer T (NKT) and gamma-delta T cells (γδ T-cells) on activated HSC. Current directions of research investigate the immune-modulating functions of HSC in the environment of liver tumors, cellular heterogeneity or interactions promoting HSC deactivation during resolution of liver fibrosis. Understanding the role of HSC as central regulators of liver immunology may lead to novel therapeutic strategies for chronic liver diseases.
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Affiliation(s)
- Ralf Weiskirchen
- 1 Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, 2 Department of Internal Medicine III, RWTH University Hospital Aachen, Aachen, Germany
| | - Frank Tacke
- 1 Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, 2 Department of Internal Medicine III, RWTH University Hospital Aachen, Aachen, Germany
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18
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Study of the therapeutic effects of Lactobacillus and α-lipoic acid against dimethylnitrosamine-induced liver fibrosis in rats. J Genet Eng Biotechnol 2014. [DOI: 10.1016/j.jgeb.2014.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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19
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Poelstra K, Beljaars L, Melgert BN. Cell-specific delivery of biologicals: problems, pitfalls and possibilities of antifibrotic compounds in the liver. Drug Discov Today 2013; 18:1237-42. [DOI: 10.1016/j.drudis.2013.05.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 05/22/2013] [Indexed: 02/06/2023]
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20
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Luo XY, Takahara T, Kawai K, Fujino M, Sugiyama T, Tsuneyama K, Tsukada K, Nakae S, Zhong L, Li XK. IFN-γ deficiency attenuates hepatic inflammation and fibrosis in a steatohepatitis model induced by a methionine- and choline-deficient high-fat diet. Am J Physiol Gastrointest Liver Physiol 2013; 305:G891-9. [PMID: 24136786 DOI: 10.1152/ajpgi.00193.2013] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cytokines play important roles in all stages of steatohepatitis, including hepatocyte injury, the inflammatory response, and the altered function of sinusoidal cells. This study examined the involvement of a major inflammatory cytokine, interferon-γ (IFN-γ), in the progression of steatohepatitis. In a steatohepatitis model by feeding a methionine- and choline-deficient high-fat (MCDHF) diet to both wild-type and IFN-γ-deficient mice, the liver histology, expression of genes encoding inflammatory cytokines, and fibrosis-related markers were examined. To analyze the effects of IFN-γ on Kupffer cells in vitro, we examined the tumor necrosis factor-α (TNF-α) production by a mouse macrophage cell line. Forty two days of MCDHF diet resulted in weight loss, elevated aminotransferases, liver steatosis, and inflammation in wild-type mice. However, the IFN-γ-deficient mice exhibited less extensive changes. RT-PCR revealed that the expression of tumor necrosis factor-α (TNF-α), transforming growth factor-β, inducible nitric oxide synthase, interleukin-4 and osteopontin were increased in wild-type mice, although they were suppressed in IFN-γ-deficient mice. Seventy days of MCDHF diet induced much more liver fibrosis in wild-type mice than in IFN-γ-deficient mice. The expression levels of fibrosis-related genes, α-smooth muscle actin, type I collagen, tissue inhibitor of matrix metalloproteinase-1, and matrix metalloproteinase-2, were dramatically increased in wild-type mice, whereas they were significantly suppressed in IFN-γ-deficient mice. Moreover, in vitro experiments showed that, when RAW 264.7 macrophages were treated with IFN-γ, they produced TNF-α in a dose-dependent manner. The present study showed that IFN-γ deficiency might inhibit the inflammatory response of macrophages cells and subsequently suppress stellate cell activation and liver fibrosis. These findings highlight the critical role of IFN-γ in the progression of steatohepatitis.
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Affiliation(s)
- Xiao-Yu Luo
- Division of Transplantation Immunology, National Research Institute for Child Health and Development, 2-10-1 Okura, Setagaya-ku, Tokyo, 157-8535 Japan.
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21
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Paulsen D, Urban A, Knorr A, Hirth-Dietrich C, Siegling A, Volk HD, Mercer AA, Limmer A, Schumak B, Knolle P, Ruebsamen-Schaeff H, Weber O. Inactivated ORF virus shows antifibrotic activity and inhibits human hepatitis B virus (HBV) and hepatitis C virus (HCV) replication in preclinical models. PLoS One 2013; 8:e74605. [PMID: 24066148 PMCID: PMC3774719 DOI: 10.1371/journal.pone.0074605] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 08/05/2013] [Indexed: 01/27/2023] Open
Abstract
Inactivated orf virus (iORFV), strain D1701, is a potent immune modulator in various animal species. We recently demonstrated that iORFV induces strong antiviral activity in animal models of acute and chronic viral infections. In addition, we found D1701-mediated antifibrotic effects in different rat models of liver fibrosis. In the present study, we compare iORFV derived from two different strains of ORFV, D1701 and NZ2, respectively, with respect to their antifibrotic potential as well as their potential to induce an antiviral response controlling infections with the hepatotropic pathogens hepatitis C virus (HCV) and hepatitis B virus (HBV). Both strains of ORFV showed anti-viral activity against HCV in vitro and against HBV in a transgenic mouse model without signs of necro-inflammation in vivo. Our experiments suggest that the absence of liver damage is potentially mediated by iORFV-induced downregulation of antigen cross-presentation in liver sinus endothelial cells. Furthermore, both strains showed significant anti-fibrotic activity in rat models of liver fibrosis. iORFV strain NZ2 appeared more potent compared to strain D1701 with respect to both its antiviral and antifibrotic activity on the basis of dosages estimated by titration of active virus. These results show a potential therapeutic approach against two important human liver pathogens HBV and HCV that independently addresses concomitant liver fibrosis. Further studies are required to characterize the details of the mechanisms involved in this novel therapeutic principle.
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Affiliation(s)
| | | | | | | | | | - Hans-Dieter Volk
- Institute of Medical Immunology and Berlin-Brandenburg Center for Regenerative Therapies (BCRT), Charité – Medical University Berlin, Berlin, Germany
- University of Heidelberg, Heidelberg, Germany
| | - Andrew A. Mercer
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Andreas Limmer
- Institutes of Molecular Medicine and Experimental Immunology, University Hospital Bonn, Bonn, Germany
| | - Beatrix Schumak
- Institute of Medical Microbiology, Immunology and Parasitology (IMMIP), University of Bonn, Bonn, Germany
| | - Percy Knolle
- Institutes of Molecular Medicine and Experimental Immunology, University Hospital Bonn, Bonn, Germany
- Institute of Molecular Immunology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany
| | | | - Olaf Weber
- Bayer HealthCare AG, Leverkusen, Germany
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22
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Gao B, Radaeva S. Natural killer and natural killer T cells in liver fibrosis. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1832:1061-9. [PMID: 23022478 PMCID: PMC3552008 DOI: 10.1016/j.bbadis.2012.09.008] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/20/2012] [Indexed: 12/22/2022]
Abstract
The liver lymphocyte population is enriched with natural killer (NK) cells, which play a key role in host defense against viral infection and tumor transformation. Recent evidence from animal models suggests that NK cells also play an important role in inhibiting liver fibrosis by selectively killing early or senescence activated hepatic stellate cells (HSCs) and by producing the anti-fibrotic cytokine IFN-γ. Furthermore, clinical studies have revealed that human NK cells can kill primary human HSCs and that the ability of NK cells from HCV patients to kill HSCs is enhanced and correlates inversely with the stages of liver fibrosis. IFN-α treatment enhances, while other factors (e.g., alcohol, TGF-β) attenuate, the cytotoxicity of NK cells against HSCs, thereby differentially regulating liver fibrogenesis. In addition, the mouse liver lymphocyte population is also enriched for natural killer T (NKT) cells, whereas human liver lymphocytes have a much lower percentage of NKT cells. Many studies suggest that NKT cells promote liver fibrogenesis by producing pro-fibrotic cytokines such as IL-4, IL-13, hedgehog ligands, and osteopontin; however, NKT cells may also attenuate liver fibrosis under certain conditions by killing HSCs and by producing IFN-γ. Finally, the potential for NK and NKT cells to be used as therapeutic targets for anti-fibrotic therapy is discussed. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Affiliation(s)
- Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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23
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Nowatzky J, Knorr A, Hirth-Dietrich C, Siegling A, Volk HD, Limmer A, Knolle P, Weber O. Inactivated Orf virus (Parapoxvirus ovis) elicits antifibrotic activity in models of liver fibrosis. Hepatol Res 2013; 43:535-46. [PMID: 22971208 DOI: 10.1111/j.1872-034x.2012.01086.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/17/2012] [Accepted: 07/30/2012] [Indexed: 02/08/2023]
Abstract
AIM Inactivated Orf virus (ORFV, Parapoxvirus ovis) demonstrates strong antiviral activity in animal models including a human hepatitis B virus (HBV)-transgenic mouse. In addition, expression of interferon (IFN)-γ and interleukin-10 (IL-10) was induced after administration of inactivated ORFV in these mice. IFN-γ and IL-10 are known to elicit antifibrotic activity. We therefore aimed to study antifibrotic activity of inactivated ORFV in models of liver fibrosis. METHODS We characterized ORFV-induced hepatic cytokine expression in rats. We then studied ORFV in two models of liver fibrosis in rats, pig serum-induced liver fibrosis and carbon tetrachloride (CCL4 )-induced liver fibrosis. RESULTS ORFV induced hepatic expression of IFN-γ and IL-10 in rats. ORFV mediated antifibrotic activity when administrated concomitantly with the fibrosis-inducing agents in both models of liver fibrosis. Importantly, when CCL4 -induced liver fibrosis was already established, ORFV application still showed significant antifibrotic activity. In addition, we were able to demonstrate a direct antifibrotic effect of ORFV on stellate cells. CONCLUSION These results establish a potential novel antifibrotic therapeutic approach that not only prevents but also resolves established liver fibrosis. Further studies are required to unravel the details of the mechanisms involved.
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Affiliation(s)
- Janina Nowatzky
- Bayer HealthCare, Wuppertal; Medical Faculty University of Witten-Herdecke, Witten
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24
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Translating an understanding of the pathogenesis of hepatic fibrosis to novel therapies. Clin Gastroenterol Hepatol 2013; 11:224-31.e1-5. [PMID: 23305825 PMCID: PMC4151461 DOI: 10.1016/j.cgh.2013.01.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The response to injury is one of wound healing and fibrogenesis, which ultimately leads to fibrosis. The fibrogenic response to injury is a generalized one across virtually all organ systems. In the liver, the injury response, typically occurring over a prolonged period of time, leads to cirrhosis (although it should be pointed out that not all patients with liver injury develop cirrhosis). The fact that many different diseases result in cirrhosis suggests a common pathogenesis. The study of hepatic fibrogenesis over the past 2 decades has been remarkably active, leading to a considerable understanding of this process. It clearly has been shown that the hepatic stellate cell is a central component in the fibrogenic process. It also has been recognized that other effector cells are important in the fibrogenic process, including resident fibroblasts, bone marrow-derived cells, fibrocytes, and even perhaps cells derived from epithelial cells (ie, through epithelial to mesenchymal transition). A key aspect of the biology of fibrogenesis is that the fibrogenic process is dynamic; thus, even advanced fibrosis (or cirrhosis) is reversible. Together, an understanding of the cellular basis for liver fibrogenesis, along with multiple aspects of the basic pathogenesis of fibrosis, have highlighted many exciting potential therapeutic opportunities. Thus, although the most effective antifibrotic therapy is simply treatment of the underlying disease, in situations in which this is not possible, specific antifibrotic therapy is likely not only to become feasible, but will soon become a reality. This review highlights the mechanisms underlying fibrogenesis that may be translated into future antifibrotic therapies and to review the current state of clinical development.
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Cheng Q, Li N, Chen M, Zheng J, Qian Z, Wang X, Huang C, Li Q, Lin Q, Shi G. Fuzheng Huayu inhibits carbon tetrachloride-induced liver fibrosis in mice through activating hepatic NK cells. JOURNAL OF ETHNOPHARMACOLOGY 2013; 145:175-181. [PMID: 23127651 DOI: 10.1016/j.jep.2012.10.047] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 10/14/2012] [Accepted: 10/25/2012] [Indexed: 06/01/2023]
Abstract
AIM OF THE STUDY Fuzheng Huayu (FZHY) is a Chinese compound herbal preparation which consists of six Chinese herbs. This study examines the preventative effects of FZHY on liver fibrosis induced by carbon tetrachloride (CCl(4)) and explores its possible mechanisms of action. MATERIALS AND METHODS Liver fibrosis was induced in male C57BL/6N mice by injecting a 10% CCl(4) solution intraperitoneal twice a week for six weeks. After 6 weeks of treatment, serum ALT and AST assay, liver tissue histological examination and immunostaining were carried out to examine the liver function and fibrosis degree. The expression levels of alpha-smooth muscle actin (SMA) were measured by quantitative real-time PCR and western blot. Hepatic natural killer (NK) cells were isolated from liver and evaluated by FACS. RESULTS Upon pathological examination, the FZHY-treated mice showed significantly reduced liver damage. The expression of α-SMA increased markedly upon treatment with CCl(4) and the increase was reversed by FZHY treatment. FZHY treatment also enhanced the activation of hepatic NK cells and the production of interferon-gamma (IFN-γ). The protective effects of FZHY were reversed in the mice that were depleted of NK cells by anti-ASGM-1 Ab treatment. CONCLUSIONS FZHY can efficiently inhibit CCl(4)-induced liver fibrosis. Furthermore, the depletion of NK cells attenuates the protective effects of FZHY. We conclude that FZHY could be an effective drug for liver fibrosis, and its mechanism of action involves the activation of hepatic NK cells.
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Affiliation(s)
- Qi Cheng
- Department of Infectious Diseases, Huashan Hospital of Fudan University, Shanghai 200040, China
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26
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Chen YH, Du BQ, Zheng ZJ, Xiang GM, Liu XB, Mai G. Effect of recombinant human growth hormone and interferon gamma on hepatic collagen synthesis and proliferation of hepatic stellate cells in cirrhotic rats. Hepatobiliary Pancreat Dis Int 2012; 11:294-301. [PMID: 22672824 DOI: 10.1016/s1499-3872(12)60163-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Fibrosis plays a key role in the development of liver cirrhosis. In this study, we investigated the effect of growth hormone and interferon gamma on hepatic collagen synthesis and the proliferation of hepatic stellate cells in a cirrhotic rat model. METHODS Cirrhosis was induced in rats using carbon tetrachloride. Rats were simultaneously treated with daily subcutaneous injections of recombinant human growth hormone or interferon gamma combined with recombinant human growth hormone. The control group was given saline. The relative content of type I and type IV collagen was assessed by indirect immunofluorescence analysis. Activated hepatic stellate cells were prepared from cirrhotic rats. The 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide (MTT) method was used to assess the effects of recombinant human growth hormone and interferon gamma on these cells in vitro. RESULTS Both qualitative and quantitative analysis showed that type I and type IV collagen secretion increased with time after recombinant human growth hormone administration and was significantly higher than control and recombinant human growth hormone combined with interferon gamma administration. In vitro, recombinant human growth hormone significantly stimulated hepatic stellate cell proliferation in a concentration-dependent manner (10(-3)-10(-1) mg/100 μL), and interferon gamma (10(-2)-10(-1) μg/100 μL) significantly inhibited their growth compared to the control group. Interferon gamma combined with recombinant human growth hormone eliminated this growth-promoting effect to a certain degree in a concentration-dependent manner (10(-1) μg/100 μL, P<0.05, 10(-2)-10(-3) μg/100 μL, P>0.05) and a time-dependent manner (P<0.05). CONCLUSIONS Recombinant human growth hormone increased collagen secretion in cirrhotic rats in vivo and promoted the proliferation of hepatic stellate cells from cirrhotic rats in vitro. It is possible that concurrent interferon gamma therapy can offset these side-effects of recombinant human growth hormone.
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Affiliation(s)
- Yong-Hua Chen
- Department of Hepatobiliopancreatic Surgery, Sichuan University, Chengdu, China
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27
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Li T, Shi Z, Rockey DC. Preproendothelin-1 expression is negatively regulated by IFNγ during hepatic stellate cell activation. Am J Physiol Gastrointest Liver Physiol 2012; 302:G948-57. [PMID: 22301113 PMCID: PMC3362071 DOI: 10.1152/ajpgi.00359.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Endothelin-1 (ET-1), a powerful vasoconstrictor peptide, is produced by activated hepatic stellate cells (HSC) and promotes cell proliferation, fibrogenesis, and contraction, the latter of which has been thought to be mechanistically linked to portal hypertension in cirrhosis. Interferon-γ (IFNγ), a Th1 cytokine produced by T cells, inhibits stellate cell proliferation, fibrogenesis, and muscle-specific gene expression. Whether IFNγ-induced inhibitory effects are linked to regulation of ET-1 expression in activated stellate cells remains unknown. Here we examined IFNγ's effects on preproET-1 mRNA expression and the signaling pathways underlying this process. We demonstrated that preproET-1 mRNA expression in HSCs was prominently increased during cell culture-induced activation; IFNγ significantly inhibited both preproET-1 mRNA expression and ET-1 peptide production. Similar results were found in an in vivo model of liver injury and intraperitoneal administration of IFNγ. PreproET-1 promoter analysis revealed that IFNγ-induced inhibition of preproET-1 mRNA expression was closely linked to the AP-1 and Smad3 signaling pathways. Furthermore, IFNγ reduced JNK phosphorylation, which tightly was associated with decreased phosphorylation of downstream factors c-Jun and Smad3 and decreased binding activity of c-Jun and Smad3 in the preprpET-1 promoter. Importantly, IFNγ reduced both c-Jun mRNA and protein levels. Given the important role of ET-1 in wound healing, our results suggest a novel negative signaling network by which IFNγ inhibits preproET-1 expression, highlighting one potential molecular mechanism for IFNγ-induced host immunomodulation of liver fibrogenesis.
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Affiliation(s)
- Tianxia Li
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Zengdun Shi
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Don C. Rockey
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
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28
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Bissell DM. Therapy for hepatic fibrosis: revisiting the preclinical models. Clin Res Hepatol Gastroenterol 2011; 35:521-5. [PMID: 21536514 DOI: 10.1016/j.clinre.2011.03.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 03/16/2011] [Indexed: 02/04/2023]
Affiliation(s)
- D Montgomery Bissell
- University of California, Box 0538, 513, Parnassus Avenue, San Francisco, CA 94143, USA.
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29
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Long-term antifibrotic action of interferon-γ treatment in patients with chronic hepatitis B virus infection. Hepatobiliary Pancreat Dis Int 2011; 10:151-7. [PMID: 21459721 DOI: 10.1016/s1499-3872(11)60024-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The first priority in treating fibrosis is to eliminate the causes that result in liver injury, e.g., hepatitis B and C virus. However, in many liver diseases the cause is either unknown or untreatable. The present study was designed to investigate the long-term antifibrotic effect of interferon-gamma (IFN-gamma) treatment in patients chronically infected with hepatitis B virus. METHODS A total of 42 patients, 30 treated with IFN-gamma and 12 controls, were enrolled from an original clinical trial (Clin Gastroenterol Hepatol 2005;3:819.). Three serial liver biopsies that were obtained at the initiation and end of IFN-gamma treatment as well as 4 to 6 years after treatment discontinuation were assessed according to the modified Chevallier scoring system. RESULTS Twenty-five out of 30 IFN-gamma-treated patients were followed up until 4 to 6 years after the treatment was stopped. However, all controls were excluded from follow-up due to death, loss and elevated virus level within 2 years. Twenty-five IFN-gamma-treated patients had stable serum liver function and liver fibrosis indices without any further anti-viral or anti-fibrotic treatment. Improved inflammatory and fibrotic scores were found after nine months of IFN-gamma treatment according to the modified Chevallier scoring system (inflammation: 11.8+/-6.5 at the beginning of IFN-gamma treatment vs. 9.2+/-4.1 after 9 months, P<0.05; fibrosis: 15.0+/-7.3 at baseline vs. 12.6+/-6.8 after 9 months, P<0.05). Among them, 14 patients accepted a third serial liver biopsy 4 to 6 years after treatment discontinuation, and the fibrotic score was increased (14.2+/-8.3 vs. 11.9+/-7.6 after 9 months, P<0.05). CONCLUSIONS Nine-month IFN-gamma treatment significantly improves the fibrosis score in patients with chronic HBV infection. The majority of patients demonstrate stable serum biochemical indices and quality of life. However, they do not show a long-term benefit according to histological criteria. Given the limited sample size, long-term IFN-gamma treatment regimens should be assessed in further clinical trials.
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Horras CJ, Lamb CL, Mitchell KA. Regulation of hepatocyte fate by interferon-γ. Cytokine Growth Factor Rev 2011; 22:35-43. [PMID: 21334249 DOI: 10.1016/j.cytogfr.2011.01.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 12/17/2010] [Accepted: 01/06/2011] [Indexed: 12/15/2022]
Abstract
Interferon (IFN)-γ is a cytokine known for its immunomodulatory and anti-proliferative action. In the liver, IFN-γ can induce hepatocyte apoptosis or inhibit hepatocyte cell cycle progression. This article reviews recent mechanistic reports that describe how IFN-γ may direct the fate of hepatocytes either towards apoptosis or a cell cycle arrest. This review also describes a probable role for IFN-γ in modulating hepatocyte fate during liver regeneration, transplantation, hepatitis, fibrosis and hepatocellular carcinoma, and highlights promising areas of research that may lead to the development of IFN-γ as a therapy to enhance recovery from liver disease.
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Affiliation(s)
- Christopher J Horras
- Department of Biological Sciences, Boise State University, 1910 University Drive, Boise, ID 83725-1515, United States
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31
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Shi Z, Rockey DC. Interferon-gamma-mediated inhibition of serum response factor-dependent smooth muscle-specific gene expression. J Biol Chem 2010; 285:32415-24. [PMID: 20685657 DOI: 10.1074/jbc.m110.164863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
IFNγ exerts multiple biological effects on effector cells by regulating many downstream genes, including smooth muscle-specific genes. However, the molecular mechanisms underlying IFNγ-induced inhibition of smooth muscle-specific gene expression remain unclear. In this study, we have shown that serum response factor (SRF), a common transcriptional factor important in cell proliferation, migration, and differentiation, is targeted by IFNγ in a STAT1-dependent manner. We show that the molecular mechanism by which IFNγ regulates SRF is via activation of the 2-5A-RNase L system, which triggers SRF mRNA decay and reduced SRF expression. As a result, decreased SRF expression reduces expression of SRF target genes such as smooth muscle α-actin and smooth muscle myosin heavy chain. Additionally, IFNγ reduced p300 and acetylated histone-3 binding in both smooth muscle α-actin and SRF promoters, epigenetically decreasing smooth muscle α-actin and SRF transcriptional activation. Our data reveal that SRF is a novel IFNγ-regulated gene and further elucidate the molecular pathway between IFNγ, IFNγ-regulated genes, and SRF and its target genes.
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Affiliation(s)
- Zengdun Shi
- Department of Internal Medicine, Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390, USA
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Mononuclear cells in liver fibrosis. Semin Immunopathol 2009; 31:345-58. [PMID: 19533130 DOI: 10.1007/s00281-009-0169-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 05/28/2009] [Indexed: 02/07/2023]
Abstract
Fibrosis is a multicellular wound healing process, where myofibroblasts that express extracellular matrix components extensively cross-talk with other cells resident in the liver or recruited from the bloodstream. Macrophages and infiltrating monocytes participate in the development of fibrosis via several mechanisms, including secretion of cytokines and generation of oxidative stress-related products. However, macrophages are also pivotal in the process of fibrosis resolution, where they contribute to matrix degradation. T lymphocytes modulate the fibrogenic process by direct interaction with myofibroblasts and secreting cytokines. In general, Th2 polarized responses promote fibrosis, while Th1 cytokines may be antifibrogenic. NK cells limit the development of fibrosis and favor its resolution, at least in part via killing of fibrogenic cells. The possible role of NKT cells and B cells is emerging in recent studies. Thus, mononuclear cells represent a critical regulatory system during fibrogenesis and may become an appealing target for therapy.
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Effect of natural interferon α on proliferation and apoptosis of hepatic stellate cells. Hepatol Int 2009; 3:497-503. [PMID: 19669254 DOI: 10.1007/s12072-009-9129-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 04/01/2009] [Indexed: 12/13/2022]
Abstract
Inhibition of the proliferation of hepatic stellate cells (HSC) is clinically important for the control of liver fibrosis and cirrhosis. Interferons are now frequently used for chronic viral hepatitis because of their anti-viral activity. However, patients treated with interferons exhibit a regression of liver fibrosis even if viral eradication is not achieved, indicating that interferon itself has anti-fibrotic activity. Herein, we show the anti-proliferation and pro-apoptotic activity of natural interferon α against HSC. We found that interferon α inhibited serum-stimulated [(3)H]thymidine incorporation of HSC in a dose-dependent manner, with a significant reduction at more than 100 U/ml. Interferon α also attenuated PDGF-BB-stimulated DNA synthesis of HSC. Although the molecular mechanism behind these phenomena has not been defined, we found that interferon α triggers the apoptosis of HSC treated with low-dose tumor necrosis factor α, as determined by the Alamar blue assay, morphology, and DNA ladder formation. Furthermore, interferon α decreased inhibitor of caspase-activated DNase (ICAD) levels, which may augment tumor necrosis factor α-induced cell death signals. Thus, interferon α regulates the number of myofibroblastic hepatic stellate cells and may clinically contribute to the regression of human liver fibrosis.
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Smedsrød B, Le Couteur D, Ikejima K, Jaeschke H, Kawada N, Naito M, Knolle P, Nagy L, Senoo H, Vidal-Vanaclocha F, Yamaguchi N. Hepatic sinusoidal cells in health and disease: update from the 14th International Symposium. Liver Int 2009; 29:490-501. [PMID: 19210626 DOI: 10.1111/j.1478-3231.2009.01979.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review aims to give an update of the field of the hepatic sinusoid, supported by references to presentations given at the 14th International Symposium on Cells of the Hepatic Sinusoid (ISCHS2008), which was held in Tromsø, Norway, August 31-September 4, 2008. The subtitle of the symposium, 'Integrating basic and clinical hepatology', signified the inclusion of both basal and applied clinical results of importance in the field of liver sinusoidal physiology and pathophysiology. Of nearly 50 oral presentations, nine were invited tutorial lectures. The authors of the review have avoided writing a 'flat summary' of the presentations given at ISCHS2008, and instead focused on important novel information. The tutorial presentations have served as a particularly important basis in the preparation of this update. In this review, we have also included references to recent literature that may not have been covered by the ISCHS2008 programme. The sections of this review reflect the scientific programme of the symposium (http://www.ub.uit.no/munin/bitstream/10037/1654/1/book.pdf): 1. Liver sinusoidal endothelial cells. 2. Kupffer cells. 3. Hepatic stellate cells. 4. Immunology. 5. Tumor/metastasis. Symposium abstracts are referred to by a number preceded by the letter A.
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Affiliation(s)
- Bård Smedsrød
- Department of Cell Biology and Histology, Institute of Medical Biology, University of Tromsø, Tromsø, Norway.
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Abstract
Chronic injury results in a wound healing response that eventually leads to fibrosis. The response is generalized, with features common among multiple organ systems. In the liver, various different types of injury lead to fibrogenesis, implying a common pathogenesis. Although several specific therapies for patients who have different liver diseases have been successfully developed, including antiviral therapies for those who have hepatitis B and hepatitis C virus infection, specific and effective antifibrotic therapy remains elusive. Over the past 2 decades, great advances in the understanding of fibrosis have been made and multiple mechanisms underlying hepatic fibrogenesis uncovered. Elucidation of these mechanisms has been of fundamental importance in highlighting novel potential therapies. Preclinical studies have indicated several putative therapies that might abrogate fibrogenesis. This article emphasizes mechanisms underlying fibrogenesis and reviews available and future therapeutics.
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Affiliation(s)
- Don C Rockey
- Division of Digestive and Liver Diseases, Department of Internal Medicine, The University of Texas, Southwestern Medical Center, Dallas, TX 75390, USA.
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Zhao C, Dai CL. Role of Kupffer cells in hepatic fibrosis. Shijie Huaren Xiaohua Zazhi 2008; 16:2959-2963. [DOI: 10.11569/wcjd.v16.i26.2959] [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
Kupffer cells (KC), a kind of nonparenchymal cells and defenders in the liver, release various chemical mediators to induce liver injury, and play an important role in many pathologic changes of the liver. Hepatic fibrosis is the common pathologic process of varied chronic liver diseases, and it is also a "transfer station" for many chronic liver diseases lapsing to cirrhosis. As important influencing factors, cytokines secreted by KC are involved in the occurrence and progression of hepatic fibrosis. Therefore, lucubrating the role and mechanism of KC in the progression of hepatic fibrosis, and investigating the KC-related therapeutic strategies of anti-fibrosis have practical significances for the prevention and treatment of liver injury and the raise of patients' survival rates in clinical practice.
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Ye Z, Houssein HSH, Mahato RI. Bioconjugation of oligonucleotides for treating liver fibrosis. Oligonucleotides 2008; 17:349-404. [PMID: 18154454 DOI: 10.1089/oli.2007.0097] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Liver fibrosis results from chronic liver injury due to hepatitis B and C, excessive alcohol ingestion, and metal ion overload. Fibrosis culminates in cirrhosis and results in liver failure. Therefore, a potent antifibrotic therapy is urgently needed to reverse scarring and eliminate progression to cirrhosis. Although activated hepatic stellate cells (HSCs) remain the principle cell type responsible for liver fibrosis, perivascular fibroblasts of portal and central veins as well as periductular fibroblasts are other sources of fibrogenic cells. This review will critically discuss various treatment strategies for liver fibrosis, including prevention of liver injury, reduction of inflammation, inhibition of HSC activation, degradation of scar matrix, and inhibition of aberrant collagen synthesis. Oligonucleotides (ODNs) are short, single-stranded nucleic acids, which disrupt expression of target protein by binding to complementary mRNA or forming triplex with genomic DNA. Triplex forming oligonucleotides (TFOs) provide an attractive strategy for treating liver fibrosis. A series of TFOs have been developed for inhibiting the transcription of alpha1(I) collagen gene, which opens a new area for antifibrotic drugs. There will be in-depth discussion on the use of TFOs and how different bioconjugation strategies can be utilized for their site-specific delivery to HSCs or hepatocytes for enhanced antifibrotic activities. Various insights developed in individual strategy and the need for multipronged approaches will also be discussed.
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Affiliation(s)
- Zhaoyang Ye
- Department of Pharmaceutical Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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Abstract
The hepatic innate immune system consists of predominant innate immunity, which plays an important role in innate defense against infection and tumor transformation. Emerging evidence suggests that innate immunity also contributes to liver injury, repair, and fibrosis. The present review summarizes the recent findings on the role of innate immunity in liver fibrosis. In general, Kupffer cells stimulate liver fibrosis via production of reactive oxygen species and pro-inflammatory cytokines, whereas natural killer (NK) cells inhibit liver fibrosis by directly killing activated hepatic stellate cells and production of gamma-interferon (IFN-gamma). Complement components, interferons, and Toll-like receptors have also been shown to regulate liver fibrosis. Recent evidence also suggests that modulation of innate immunity by alcohol plays an important role in the pathogenesis of alcoholic liver fibrosis. These include alcohol amplification of the profibrotic effects of Kupffer cells and suppression of the antifibrotic effects of NK/IFN-gamma.
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Affiliation(s)
- Won-Il Jeong
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892, USA
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JEONG WON, PARK OGYI, GAO BIN. Abrogation of the antifibrotic effects of natural killer cells/interferon-gamma contributes to alcohol acceleration of liver fibrosis. Gastroenterology 2008; 134:248-58. [PMID: 18166357 PMCID: PMC2923436 DOI: 10.1053/j.gastro.2007.09.034] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2007] [Accepted: 09/13/2007] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS Chronic alcohol drinking accelerates liver fibrosis in patients with viral hepatitis that cannot be fully explained by ethanol-enhanced liver damage. Here, we identified a novel mechanism by which alcohol accelerates liver fibrosis: inhibition of the antifibrotic effects of natural killer (NK) cells and interferon-gamma (IFN-gamma). METHODS Alcohol administration was achieved by feeding mice with a liquid diet containing 5% ethanol for 8 weeks. Liver fibrosis was induced by administration of carbon tetrachloride (CCl(4)) for 2 weeks. Hepatic stellate cells (HSCs) were also isolated and cultured for in vitro studies. RESULTS CCl(4) treatment induced greater fibrosis and less apoptosis of HSCs in ethanol-fed mice compared with pair-fed mice. Polyinosinic-polycytidylic acid (Poly I:C) or IFN-gamma treatment inhibited liver fibrosis in pair-fed but not in ethanol-fed mice. Poly I:C activation of NK cell cytotoxicity against HSCs was attenuated in ethanol-fed mice compared with pair-fed mice, which was due to reduced natural killer group 2 member D (NKG2D), tumor necrosis factor-related apoptosis-inducing ligand, and IFN-gamma expression on NK cells from ethanol-fed mice. In vitro, HSCs from ethanol-fed mice were resistant to IFN-gamma-induced cell cycle arrest and apoptosis compared with pair-fed mice. Such resistance was due to diminished IFN-gamma activation of signal transducer and activator of transcription 1 (STAT1) in HSCs from ethanol-fed mice caused by the induction of suppressors of cytokine signaling proteins and the production of oxidative stress. Finally, HSCs from ethanol-fed mice were resistant to NK cell killing, which can be reversed by transforming growth factor-beta1 (TGF-beta1) neutralizing antibody. CONCLUSIONS Chronic ethanol consumption attenuates the antifibrotic effects of NK/IFN-gamma/STAT1 in the liver, representing new and different therapeutic targets with which to treat alcoholic liver fibrosis.
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Fu Y, Zheng S, Lin J, Ryerse J, Chen A. Curcumin protects the rat liver from CCl4-caused injury and fibrogenesis by attenuating oxidative stress and suppressing inflammation. Mol Pharmacol 2007; 73:399-409. [PMID: 18006644 DOI: 10.1124/mol.107.039818] [Citation(s) in RCA: 291] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
We previously demonstrated that curcumin, a polyphenolic antioxidant purified from turmeric, up-regulated peroxisome proliferator-activated receptor (PPAR)-gamma gene expression and stimulated its signaling, leading to the inhibition of activation of hepatic stellate cells (HSC) in vitro. The current study evaluates the in vivo role of curcumin in protecting the liver against injury and fibrogenesis caused by carbon tetrachloride (CCl(4)) in rats and further explores the underlying mechanisms. We hypothesize that curcumin might protect the liver from CCl(4)-caused injury and fibrogenesis by attenuating oxidative stress, suppressing inflammation, and inhibiting activation of HSC. This report demonstrates that curcumin significantly protects the liver from injury by reducing the activities of serum aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase, and by improving the histological architecture of the liver. In addition, curcumin attenuates oxidative stress by increasing the content of hepatic glutathione, leading to the reduction in the level of lipid hydroperoxide. Curcumin dramatically suppresses inflammation by reducing levels of inflammatory cytokines, including interferon-gamma, tumor necrosis factor-alpha, and interleukin-6. Furthermore, curcumin inhibits HSC activation by elevating the level of PPARgamma and reducing the abundance of platelet-derived growth factor, transforming growth factor-beta, their receptors, and type I collagen. This study demonstrates that curcumin protects the rat liver from CCl(4)-caused injury and fibrogenesis by suppressing hepatic inflammation, attenuating hepatic oxidative stress and inhibiting HSC activation. These results confirm and extend our prior in vitro observations and provide novel insights into the mechanisms of curcumin in the protection of the liver. Our results suggest that curcumin might be a therapeutic antifibrotic agent for the treatment of hepatic fibrosis.
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Affiliation(s)
- Yumei Fu
- Department of Pathology, School of Medicine, Saint Louis University, 1402 S. Grand Blvd., St. Louis, MO 63104, USA
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Gao B, Radaeva S, Jeong WI. Activation of natural killer cells inhibits liver fibrosis: a novel strategy to treat liver fibrosis. Expert Rev Gastroenterol Hepatol 2007; 1:173-80. [PMID: 19072444 DOI: 10.1586/17474124.1.1.173] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Liver lymphocytes are enriched in natural killer (NK) cells, which are involved in innate immune defenses against viral infection and tumor transformation in the liver. Recent evidence indicates that NK cell activation by IFN-alpha, IFN-gamma or dsRNA attenuates liver fibrosis through the direct killing of activated hepatic stellate cells (HSCs). Interestingly, NK cells do not kill quiescent or fully activated HSCs, but only early-activated HSCs, as only these cells express elevated levels of the NK cell-activating ligand retinoic acid-induced early transcript (RAE)-1 and TNF-related apoptosis-inducing ligand receptors, in addition to downregulated levels of the NK-cell inhibitory ligand, MHC-I. Inhibition of liver fibrosis by NK cells can also be achieved through production of IFN-gamma, which induces HSC cell cycle arrest and apoptosis in a STAT1-dependent manner. Clinically, it has also been observed that NK cell activity is negatively correlated with liver fibrosis in patients with chronic hepatitis C infection. Therefore, since NK cells inhibit liver fibrosis, stimulating NK activity could potentially be a novel strategy to treat liver fibrosis. Clinical studies will be required to confirm whether stimulating NK cell activity is effective and safe in treating human liver fibrosis.
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Affiliation(s)
- Bin Gao
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5625 Fishers Lane, Room 2S-33, Bethesda, MD 20892-8115, USA.
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Weng H, Mertens PR, Gressner AM, Dooley S. IFN-gamma abrogates profibrogenic TGF-beta signaling in liver by targeting expression of inhibitory and receptor Smads. J Hepatol 2007; 46:295-303. [PMID: 17125875 DOI: 10.1016/j.jhep.2006.09.014] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 08/29/2006] [Accepted: 09/09/2006] [Indexed: 01/18/2023]
Abstract
BACKGROUND/AIMS In a randomized open-labeled multicenter trial with patients suffering from chronic HBV infection, we recently identified a benefit of 9-month IFN-gamma treatment resulting in decreased fibrosis scores and a reduced number of alpha-smooth muscle actin-positive hepatic stellate cells (HSCs). Approaches opposing profibrogenic activities of TGF-beta may be amenable in chronic liver disease. According to experimental models, IFN-gamma counteracts several TGF-beta effects. METHODS The crosstalk of IFN-gamma and TGF-beta signaling relevant for fibrogenesis was investigated in primary cultured rat HSCs and a cell line representing activated HSCs. RESULTS In vitro studies with HSCs demonstrate that TGF-beta-dependent activation of (CAGA)9-MLP-Luc, a Smad3/4 responsive reporter construct, was significantly decreased by IFN-gamma, indicating a TGF-beta antagonizing function. IFN-gamma induced the activity of the Smad7 promoter and Smad7 protein expression via STAT-1 signaling. In contrast to TGF-beta, IFN-gamma was able to induce Smad7 expression in activated HSCs providing increased protein levels for at least 12h. In addition, expression of Smad2/3 was reduced by IFN-gamma and activation of Smads2/3 was abrogated. CONCLUSIONS IFN-gamma displays antifibrotic effects in liver cells via STAT-1 phosphorylation, upregulation of Smad7 expression and impaired TGF-beta signaling.
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Affiliation(s)
- Honglei Weng
- Institute of Infectious Diseases, The First Affiliated Hospital, School of Medicine, Zhejiang University, People's Republic of China
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Knight B, Akhurst B, Matthews VB, Ruddell RG, Ramm GA, Abraham LJ, Olynyk JK, Yeoh GC. Attenuated liver progenitor (oval) cell and fibrogenic responses to the choline deficient, ethionine supplemented diet in the BALB/c inbred strain of mice. J Hepatol 2007; 46:134-41. [PMID: 17112626 DOI: 10.1016/j.jhep.2006.08.015] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 07/24/2006] [Accepted: 08/21/2006] [Indexed: 01/07/2023]
Abstract
BACKGROUND/AIMS Liver regeneration following chronic injury is associated with inflammation, the proliferation of liver progenitor (oval) cells and fibrosis. Previous studies identified interferon-gamma as a key mediator of oval cell proliferation. Interferon-gamma is known to regulate Th1 cell activities during immune challenge. Therefore, we hypothesised that progenitor cell-mediated regeneration is associated with a Th1 immune response. METHODS C57Bl/6 (normal Th1 response) and BALB/c mice (deficient in Th1 signalling) were placed on a carcinogenic diet to induce liver injury, progenitor cell proliferation and fibrosis. RESULTS Serum transaminases and mortality were elevated in BALB/c mice fed the diet. Proliferation of liver progenitor cells was significantly attenuated in BALB/c animals. The pattern of cytokine expression and inflammation differed between strains. Liver fibrosis and hepatic stellate cell activation were significantly inhibited in BALB/c mice compared to C57Bl/6. In addition, interferon-gamma knockout mice also showed reduced fibrosis compared to wild type. These findings are in contrast to published results, in which interferon-gamma is shown to be anti-fibrogenic. CONCLUSIONS Our data demonstrate that the hepatic progenitor cell response to a CDE diet is inhibited in mice lacking Th1 immune signalling and further show that this inhibition is associated with reduced liver fibrosis.
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Affiliation(s)
- Belinda Knight
- School of Medicine and Pharmacology, University of Western Australia, Fremantle Hospital, Alma Rd., Fremantle, WA 6101, Australia.
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Jeong WI, Park O, Radaeva S, Gao B. STAT1 inhibits liver fibrosis in mice by inhibiting stellate cell proliferation and stimulating NK cell cytotoxicity. Hepatology 2006; 44:1441-51. [PMID: 17133483 DOI: 10.1002/hep.21419] [Citation(s) in RCA: 207] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Liver fibrosis, a common scarring response to chronic liver injury, is a precursor to cirrhosis and liver cancer. Here, we identified signal transducer and activator of transcription 1 (STAT1) as an important negative regulator in liver fibrosis. Our findings show that disruption of the STAT1 gene accelerated liver fibrosis and hepatic stellate cell (HSC) proliferation in an in vivo model of carbon tetrachloride (CCl4)-induced liver fibrosis. In vitro treatment with IFN-gamma inhibited proliferation and activation of wild-type HSCs, but not STAT1-/- HSCs. Moreover, compared to wild-type cells, cellular proliferation stimulated by serum or platelet-derived growth factor (PDGF) was enhanced and accelerated in STAT1-/- HSCs, which was partially mediated via elevated PDGF receptor beta expression on such cells. Polyinosinic-polycytidylic acid (poly I:C) or IFN-gamma treatment inhibited liver fibrosis in wild-type mice but not in STAT1-/- mice. Induction of NK cell killing of activated HSCs by poly I:C was attenuated in STAT1-/- mice compared to wild-type mice, which was likely due to reduced NKG2D and TRAIL expression on STAT1-/- NK cells. Finally, activation of TGF-beta/Smad3 signaling pathway was accelerated, whereas induction of Smad7 was diminished in the liver of STAT1-/- mice after CCl4 administration compared to wild-type mice. In conclusion, activation of STAT1 attenuates liver fibrosis through inhibition of HSC proliferation, attenuation of TGF-beta signaling, and stimulation of NK cell killing of activated HSCs. STAT1 could be a new therapeutic target for treating liver fibrosis.
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Affiliation(s)
- Won-Il Jeong
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
Fibrotic liver disease occurs after any of the various forms of injury to the liver. Fibrosis is a critical factor leading to hepatic dysfunction and portal hypertension and its complications. The fibrogenic cascade is complex but leads to accumulation of extracellular matrix proteins, followed by nodular fibrosis, tissue contraction, and alteration in blood flow. A critical concept emerging is that activation of effector cells, which produce extracellular matrix, underlies the fibrogenic process. The aggregate data has not only helped lead to an understanding of the pathophysiologic basis of hepatic fibrogenesis, but it has also provided an important context with which to base novel antifibrotic therapy.
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Affiliation(s)
- Don C Rockey
- Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8887, USA.
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Abstract
Hepatic fibrogenesis is the common result of injury to the liver. It is believed to be a critical factor that leads to hepatic dysfunction and may be important in portal hypertension. The fibrogenic response is a complex process in which accumulation of extracellular matrix proteins, tissue contraction, and alteration in blood flow are prominent. A critical event in fibrogenesis is activation of resident perisinusoidal cells that are termed "hepatic stellate cells". Stellate cell activation is characterized by many important phenotypes, including enhanced extracellular matrix synthesis and prominent contractility. Given the central role of stellate cell activation in hepatic fibrogenesis (and portal hypertension), effective therapy for hepatic fibrogenesis is most likely will be directed at this event.
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Affiliation(s)
- Don C Rockey
- Division of Digestive and Liver Diseases, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-8887, USA.
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Tang JT, Fang JY, Gu WQ, Li EL. T cell immune response is correlated with fibrosis and inflammatory activity in hepatitis B cirrhotics. World J Gastroenterol 2006; 12:3015-9. [PMID: 16718780 PMCID: PMC4124374 DOI: 10.3748/wjg.v12.i19.3015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To explore the relationship among interferon-γ (IFN-γ) activity, fibrogenesis, T cell immune responses and hepatic inflammatory activity.
METHODS: Peripheral blood samples from a total of 43 hepatitis B cirrhotic patients (LC) and 19 healthy controls (NC) were collected to measure their serum levels of IFN-γ, interleukin-2 (IL-2), soluble interleukin-2 receptor (sIL-2R), interleukin-10 (IL-10) and three serological markers of fibrosis including hyaluronic acid (HA), procollagen type III peptide (PIIIP), and type IV collagen were measured using a double antibody sandwich ELISA. Also, serum total bilirubin (TB) and alanine aminotransferase (ALT) were measured by routine measures.
RESULTS: The concentrations of serological markers of fibrosis in patients with active cirrhosis (ALC) were significantly higher than those in stationary liver cirrhosis (SLC) or NC groups. The levels of serological markers in HBeAg-positive patients were significantly higher than those in HBeAg-negative patients. In SLC and ALC patients, a negative linear correlation was found between IFN-γ levels and the serological markers of fibrosis. IFN-γ and IL-2 levels in the ALC group were significantly higher than those in the SLC and NC groups, but the statistical difference was not significant between the latter two. In contrast, IL-10 levels in the SLC group were significantly higher than that in the NC group, but no significant difference was found between SLC and ALC groups. The sIL-2R level was elevated gradually in all these groups, and the differences were significant. Positive linear correlations were seen between IFN-γ activity and ALT levels (r = 0.339, P < 0.05), and IL-2 activity and TB levels (r = 0.517, P < 0.05). sIL-2R expression was positively correlated with both ALT and TB levels (r = 0.324, 0.455, P < 0.05), whereas there was no statistically significant correlation between IL-10 expression and serum ALT and TB levels (r = -0.102, -0.093, P > 0.05). Finally, there was a positive correlation between IFN-γ and IL-2 levels.
CONCLUSION: T cell immune responses are correlated with fibrosis and hepatic inflammatory activity and may play an important role in liver cirrhosis.
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Affiliation(s)
- Jie-Ting Tang
- Department of Gastroenterology, Renji Hospital, Shanghai Institute of Digestive Disease, Shanghai JiaoTong University, Shanghai 200001, China
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Abstract
Given that the complications of hepatitis C are due to fibrosis, we hypothesized that the antifibrotic effects of interferon gamma on stellate cells would lead to beneficial effects in patients with hepatitis C. Thus, we evaluated the safety and efficacy of interferon gamma-1b in patients with hepatitis C. A cohort of 20 patients with chronic hepatitis C who failed or were intolerant to previous interferon-alpha-based regimens received 200 mug of interferon gamma-1b subcutaneously three times weekly for 24 weeks. Liver biopsy was performed prior to and at the end of treatment. Biopsies were evaluated by a single blinded pathologist using the Knodell system modified by Ishak, and fibrosis was also quantitated by morphometric analysis. The study population was 75% male and 70% Caucasian. Mean age was 47.9 +/- 7.5 years. Eighteen of 20 patients completed therapy. One patient discontinued therapy because of constitutional symptoms. One patient discontinued therapy because of elevated aminotransferases greater than twice baseline. No serious adverse events occurred. Morphometric analysis revealed that six patients (30%) had >1% absolute reduction in fibrosis score. Four of 20 (20%) patients had improvement in Ishak fibrosis scores after treatment. In conclusion, interferon gamma therapy is safe and well tolerated in patients with chronic hepatitis C. Although we did not detect an overall reduction in fibrosis, interferon gamma-1b treatment led to a reduction in fibrosis in selected patients. These data provide a basis for further study of interferon gamma-1b in patients with chronic fibrosing liver disease.
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Affiliation(s)
- A J Muir
- Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA.
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Radaeva S, Sun R, Jaruga B, Nguyen VT, Tian Z, Gao B. Natural killer cells ameliorate liver fibrosis by killing activated stellate cells in NKG2D-dependent and tumor necrosis factor-related apoptosis-inducing ligand-dependent manners. Gastroenterology 2006; 130:435-52. [PMID: 16472598 DOI: 10.1053/j.gastro.2005.10.055] [Citation(s) in RCA: 443] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2005] [Accepted: 10/19/2005] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Viral hepatitis infection, which is a major cause of liver fibrosis, is associated with activation of innate immunity. However, the role of innate immunity in liver fibrosis remains obscure. METHODS Liver fibrosis was induced either by feeding mice with the 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet or by injecting them with carbon tetrachloride. The Toll-like receptor 3 ligand, polyinosinic-polycytidylic acid, was used to activate innate immunity cells and mediators, including natural killer cells and interferon gamma. RESULTS In the mouse model of DDC-induced liver fibrosis, natural killer cell activation by polyinosinic-polycytidylic acid induced cell death to activated hepatic stellate cells and attenuated the severity of liver fibrosis. Polyinosinic-polycytidylic acid treatment also ameliorated liver fibrosis induced by carbon tetrachloride. The observed protective effect of polyinosinic-polycytidylic acid on liver fibrosis was diminished through either depletion of natural killer cells or by disruption of the interferon gamma gene. Expression of retinoic acid early inducible 1, the NKG2D ligand, was undetectable on quiescent hepatic stellate cells, whereas high levels were found on activated hepatic stellate cells, which correlated with the resistance and susceptibility of quiescent hepatic stellate cells and activated hepatic stellate cells to natural killer cell lysis, respectively. Moreover, treatment with polyinosinic-polycytidylic acid or interferon gamma enhanced the cytotoxicity of natural killer cells against activated hepatic stellate cells and increased the expression of NKG2D and tumor necrosis factor-related apoptosis-inducing ligand on liver natural killer cells. Blocking NKG2D or tumor necrosis factor-related apoptosis-inducing ligand with neutralizing antibodies markedly diminished the cytotoxicity of polyinosinic-polycytidylic acid-activated natural killer cells against activated hepatic stellate cells. CONCLUSIONS Our findings suggest that natural killer cells kill activated hepatic stellate cells via retinoic acid early inducible 1/NKG2D-dependent and tumor necrosis factor-related apoptosis-inducing ligand-dependent mechanisms, thereby ameliorating liver fibrosis.
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MESH Headings
- Animals
- Apoptosis/immunology
- DNA Primers
- Disease Models, Animal
- Flow Cytometry
- Hepatitis, Viral, Animal/immunology
- Killer Cells, Natural/immunology
- Ligands
- Liver Cirrhosis, Experimental/immunology
- Male
- Membrane Glycoproteins/deficiency
- Membrane Glycoproteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- NK Cell Lectin-Like Receptor Subfamily K
- Perforin
- Pore Forming Cytotoxic Proteins
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Receptors, Natural Killer Cell
- Reverse Transcriptase Polymerase Chain Reaction
- Tretinoin/physiology
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Affiliation(s)
- Svetlana Radaeva
- Section on Liver Biology, Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892, USA
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50
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Giannopoulou M, Iszkula SC, Dai C, Tan X, Yang J, Michalopoulos GK, Liu Y. Distinctive role of Stat3 and Erk-1/2 activation in mediating interferon-gamma inhibition of TGF-beta1 action. Am J Physiol Renal Physiol 2005; 290:F1234-40. [PMID: 16332928 PMCID: PMC1821083 DOI: 10.1152/ajprenal.00388.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Interferon-gamma (IFN-gamma) is a multifunctional cytokine that elicits antifibrotic activity in a variety of organs. In this study, we investigated the potential role and mechanism of IFN-gamma in modulating the fibrogenic action of transforming growth factor (TGF)-beta(1) in tubular epithelial cells. Incubation of human proximal tubular epithelial (HKC) cells with IFN-gamma inhibited TGF-beta(1)-mediated alpha-smooth muscle actin (alpha-SMA) expression. IFN-gamma also abolished TGF-beta(1)-induced fibronectin and plasminogen activator inhibitor-1 (PAI-1) expression. To explore the mechanisms by which INF-gamma inhibits TGF-beta(1) action, the signaling pathways that are critical for mediating the antifibrotic activity of IFN-gamma were studied. Stimulation of HKC cells with IFN-gamma triggered a sustained activation of Erk-1/2 and signal transducer and activator of transcription-3 (Stat3). Blockade of Erk-1/2 activation with an Mek1 inhibitor abolished the inhibitory effect of IFN-gamma on alpha-SMA expression, whereas inhibition of Stat3 activation had no influence. Constitutive activation of Erk-1/2 by ectopic expression of activated Mek1 mimicked IFN-gamma and suppressed TGF-beta(1)-mediated alpha-SMA expression. Interestingly, inhibition of Stat3 activation abolished the ability of IFN-gamma to attenuate TGF-beta(1)-mediated PAI-1 and fibronectin expression in HKC cells. These findings indicate that IFN-gamma is capable of antagonizing the fibrogenic actions of TGF-beta(1) in renal tubular epithelial cells. The antifibrotic action of IFN-gamma appears to be mediated through a coordinated activation of both Erk-1/2 and Stat3 signal pathways in a mutually independent fashion.
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Affiliation(s)
- Myrto Giannopoulou
- Dept. of Pathology, Univ. of Pittsburgh, S-405 Biomedical Science Tower, 200 Lothrop St., Pittsburgh, PA 15261, USA
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