1
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Schott MB, Rozeveld CN, Bhatt S, Crossman B, Krueger EW, Weller SG, Rasineni K, Casey CA, McNiven MA. Ethanol disrupts hepatocellular lipophagy by altering Rab5-centric LD-lysosome trafficking. Hepatol Commun 2024; 8:e0446. [PMID: 38780316 PMCID: PMC11124685 DOI: 10.1097/hc9.0000000000000446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 02/23/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Previous reports suggest that lipid droplets (LDs) in the hepatocyte can be catabolized by a direct engulfment from nearby endolysosomes (microlipophagy). Further, it is likely that this process is compromised by chronic ethanol (EtOH) exposure leading to hepatic steatosis. This study investigates the hepatocellular machinery supporting microlipophagy and EtOH-induced alterations in this process with a focus on the small, endosome-associated, GTPase Rab5. METHODS AND RESULTS Here we report that this small Ras-related GTPase is a resident component of LDs, and its activity is important for hepatocellular LD-lysosome proximity and physical interactions. We find that Rab5 siRNA knockdown causes an accumulation of LDs in hepatocytes by inhibiting lysosome dependent LD catabolism. Importantly, Rab5 appears to support this process by mediating the recruitment of early endosomal and or multivesicular body compartments to the LD surface before lysosome fusion. Interestingly, while wild-type or a constituently active GTPase form (Q79L) of Rab5 supports LD-lysosome transport, this process is markedly reduced in cells expressing a GTPase dead (S34N) Rab5 protein or in hepatocytes exposed to chronic EtOH. CONCLUSIONS These findings support the novel premise of an early endosomal/multivesicular body intermediate compartment on the LD surface that provides a "docking" site for lysosomal trafficking, not unlike the process that occurs during the hepatocellular degradation of endocytosed ligands that is also known to be compromised by EtOH exposure.
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Affiliation(s)
- Micah B. Schott
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Cody N. Rozeveld
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Saumya Bhatt
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Bridget Crossman
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Eugene W. Krueger
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Shaun G. Weller
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Karuna Rasineni
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Veterans’ Affairs, VA-Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
| | - Carol A. Casey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska, USA
- Department of Veterans’ Affairs, VA-Nebraska-Western Iowa Health Care System, Omaha, Nebraska, USA
| | - Mark A. McNiven
- Department of Biochemistry and Molecular Biology, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
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2
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Zhang Z, Leng XK, Zhai YY, Zhang X, Sun ZW, Xiao JY, Lu JF, Liu K, Xia B, Gao Q, Jia M, Xu CQ, Jiang YN, Zhang XG, Tao KS, Wu JW. Deficiency of ASGR1 promotes liver injury by increasing GP73-mediated hepatic endoplasmic reticulum stress. Nat Commun 2024; 15:1908. [PMID: 38459023 PMCID: PMC10924105 DOI: 10.1038/s41467-024-46135-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 02/13/2024] [Indexed: 03/10/2024] Open
Abstract
Liver injury is a core pathological process in the majority of liver diseases, yet the genetic factors predisposing individuals to its initiation and progression remain poorly understood. Here we show that asialoglycoprotein receptor 1 (ASGR1), a lectin specifically expressed in the liver, is downregulated in patients with liver fibrosis or cirrhosis and male mice with liver injury. ASGR1 deficiency exacerbates while its overexpression mitigates acetaminophen-induced acute and CCl4-induced chronic liver injuries in male mice. Mechanistically, ASGR1 binds to an endoplasmic reticulum stress mediator GP73 and facilitates its lysosomal degradation. ASGR1 depletion increases circulating GP73 levels and promotes the interaction between GP73 and BIP to activate endoplasmic reticulum stress, leading to liver injury. Neutralization of GP73 not only attenuates ASGR1 deficiency-induced liver injuries but also improves survival in mice received a lethal dose of acetaminophen. Collectively, these findings identify ASGR1 as a potential genetic determinant of susceptibility to liver injury and propose it as a therapeutic target for the treatment of liver injury.
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Affiliation(s)
- Zhe Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xiang Kai Leng
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Yuan Yuan Zhai
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Xiao Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Zhi Wei Sun
- Beijing Sungen Biomedical Technology Co. Ltd, Beijing, China
| | - Jun Ying Xiao
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jun Feng Lu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Kun Liu
- Department of Hepatobiliary Surgery, Xi-Jing Hospital, Air Force Medical University, Xi'an, China
| | - Bo Xia
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Qi Gao
- Beijing Sungen Biomedical Technology Co. Ltd, Beijing, China
| | - Miao Jia
- Beijing Sungen Biomedical Technology Co. Ltd, Beijing, China
| | - Cheng Qi Xu
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yi Na Jiang
- Department of Pathology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Xiao Gang Zhang
- Department of Hepatobiliary Surgery, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
| | - Kai Shan Tao
- Department of Hepatobiliary Surgery, Xi-Jing Hospital, Air Force Medical University, Xi'an, China.
| | - Jiang Wei Wu
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China.
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3
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Neuman MG, Seitz HK, Tuma PL, Osna NA, Casey CA, Kharbanda KK, Cohen LB, Malnick SDH, Adhikari R, Mitra R, Dagur RS, Ganesan M, Srinivas C, Madan Kumar A, New-Aaron M, Poluektova L, Thomes PG, Rasineni K, Opris M, Teschke R. Alcohol: basic and translational research; 15th annual Charles Lieber &1st Samuel French satellite symposium. Exp Mol Pathol 2022; 126:104750. [PMID: 35192844 PMCID: PMC9167794 DOI: 10.1016/j.yexmp.2022.104750] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/28/2021] [Accepted: 01/24/2022] [Indexed: 02/05/2023]
Abstract
The present review is based on the research presented at the symposium dedicated to the legacy of the two scientists that made important discoveries in the field of alcohol-induced liver damage: Professors C.S. Lieber and S.W. French. The invited speakers described pharmacological, toxicological and patho-physiological effects of alcohol misuse. Moreover, genetic biomarkers determining adverse drug reactions due to interactions between therapeutics used for chronic or infectious diseases and alcohol exposure were discussed. The researchers presented their work in areas of alcohol-induced impairment in lipid protein trafficking and endocytosis, as well as the role of lipids in the development of fatty liver. The researchers showed that alcohol leads to covalent modifications that promote hepatic dysfunction and injury. We concluded that using new advanced techniques and research ideas leads to important discoveries in science.
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Affiliation(s)
- Manuela G Neuman
- In Vitro Drug Safety and Biotechnology, Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada.
| | - Helmut K Seitz
- Centre of Liver and Alcohol Diseases, Ethianum Clinic, University of Heidelberg, Germany
| | - Pamela L Tuma
- The Catholic University of America, Department of Biology, Washington, DC 20064, USA
| | - Natalia A Osna
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Carol A Casey
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kusum K Kharbanda
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Lawrence B Cohen
- Division of Gastroenterology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Canada
| | - Steve D H Malnick
- Department of Internal Medicine C, Kaplan Medical Center, Affiliated Hebrew University, Jerusalem, Israel
| | - Raghabendra Adhikari
- The Catholic University of America, Department of Biology, Washington, DC 20064, USA
| | - Ramyajit Mitra
- The Catholic University of America, Department of Biology, Washington, DC 20064, USA
| | - Raghubendra Singh Dagur
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Murali Ganesan
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Chava Srinivas
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Arumugam Madan Kumar
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Moses New-Aaron
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Larisa Poluektova
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul G Thomes
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Karuna Rasineni
- VA-Nebraska-Western Iowa Health Care System, Department of Veterans' Affairs, Omaha, NE, and Department of Internal Medicine, Section of Gastroenterology-Hepatology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Mihai Opris
- In Vitro Drug Safety and Biotechnology, Department of Pharmacology and Toxicology, University of Toronto, Toronto, Canada; Family Medicine Clinic CAR, Bucharest, Romania
| | - Rolf Teschke
- Department of Internal Medicine II, Division of Gastroenterology and Hepatology, Klinikum Hanau, Hanau, Academic Teaching Hospital of the Medical Faculty, Goethe University Frankfurt/ Main, Frankfurt/Main, Germany
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4
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Rasineni K, Lee SML, McVicker BL, Osna NA, Casey CA, Kharbanda KK. Susceptibility of Asialoglycoprotein Receptor-Deficient Mice to Lps/Galactosamine Liver Injury and Protection by Betaine Administration. BIOLOGY 2020; 10:biology10010019. [PMID: 33396223 PMCID: PMC7823640 DOI: 10.3390/biology10010019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 12/27/2020] [Indexed: 02/05/2023]
Abstract
BACKGROUND Work from our laboratory has shown that the ethanol-induced increase in apoptotic hepatocellular death is closely related to the impairment in the ability of the asialoglycoprotein receptor (ASGP-R) to remove neighboring apoptotic cells. In this study, we assessed the role of ASGP-R in fulminant liver failure and investigated whether prior treatment with betaine (a naturally occurring tertiary amine) is protective. METHODS Lipopolysaccharide (LPS; 50 μg/kg BW) and galactosamine (GalN; 350 mg/kg BW) were injected together to wild-type and ASGP-R-deficient mice that were treated for two weeks prior with or without 2% betaine in drinking water. The mice were sacrificed 1.5, 3, or 4.5 h post-injection, and tissue samples were collected. RESULTS LPS/GalN injection generate distinct molecular processes, which includes increased production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), thus causing apoptosis as evident by increased caspase-3 activity. ASGP-R deficient animals showed increased liver caspase activities, serum TNF-α and IL-6 levels, as well as more pronounced liver damage compared with the wild-type control animals after intraperitoneal injection of LPS/GalN. In addition, prior administration of betaine was found to significantly attenuate the LPS/GalN-induced increases in liver injury parameters. CONCLUSION Our work underscores the importance of normal functioning of ASGP-R in preventing severe liver damage and signifies a therapeutic role of betaine in prevention of liver injuries from toxin-induced fulminant liver failure.
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Affiliation(s)
- Karuna Rasineni
- Research Service, Veterans’ Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (K.R.); (B.L.M.); (N.A.O.); (C.A.C.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Serene M. L. Lee
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Benita L. McVicker
- Research Service, Veterans’ Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (K.R.); (B.L.M.); (N.A.O.); (C.A.C.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Natalia A. Osna
- Research Service, Veterans’ Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (K.R.); (B.L.M.); (N.A.O.); (C.A.C.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Carol A. Casey
- Research Service, Veterans’ Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (K.R.); (B.L.M.); (N.A.O.); (C.A.C.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kusum K. Kharbanda
- Research Service, Veterans’ Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (K.R.); (B.L.M.); (N.A.O.); (C.A.C.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA;
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Correspondence: ; Tel.: +1-402-995-3752; Fax: +1-402-995-4600
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5
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Thomes PG, Rasineni K, Yang L, Donohue TM, Kubik JL, McNiven MA, Casey CA. Ethanol withdrawal mitigates fatty liver by normalizing lipid catabolism. Am J Physiol Gastrointest Liver Physiol 2019; 316:G509-G518. [PMID: 30714813 PMCID: PMC6957361 DOI: 10.1152/ajpgi.00376.2018] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We are investigating the changes in hepatic lipid catabolism that contribute to alcohol-induced fatty liver. Following chronic ethanol (EtOH) exposure, abstinence from alcohol resolves steatosis. Here, we investigated the hepatocellular events that lead to this resolution by quantifying specific catabolic parameters that returned to control levels after EtOH was withdrawn. We hypothesized that, after its chronic consumption, EtOH withdrawal reactivates lipid catabolic processes that restore lipostasis. Male Wistar rats were fed control and EtOH liquid diets for 6 wk. Randomly chosen EtOH-fed rats were then fed control diet for 7 days. Liver triglycerides (TG), lipid peroxides, key markers of fatty acid (FA) metabolism, lipophagy, and autophagy were quantified. Compared with controls, EtOH-fed rats had higher hepatic triglycerides, lipid peroxides, and serum free fatty acids (FFA). The latter findings were associated with higher levels of FA transporters (FATP 2, 4, and 5) but lower quantities of peroxisome proliferator-activated receptor-α (PPAR-α), which governs FA oxidation. EtOH-fed animals also had lower nuclear levels of the autophagy-regulating transcription factor EB (TFEB), associated with lower hepatic lipophagy and autophagy. After EtOH-fed rats were refed control diet for 7 days, their serum FFA levels and those of FATPs fell to control (normal) levels, whereas PPAR-α levels rose to normal. Hepatic TG and malondialdehyde levels in EtOH-withdrawn rats declined to near control levels. EtOH withdrawal restored nuclear TFEB content, hepatic lipophagy, and autophagy activity to control levels. EtOH withdrawal reversed aberrant FA metabolism and restored lysosomal function to promote resolution of alcohol-induced fatty liver. NEW & NOTEWORTHY Here, using an animal model, we show mechanisms of reversal of fatty liver and injury following EtOH withdrawal. Our data indicate that reactivation of autophagy and lysosome function through the restoration of transcription factor EB contribute to reversal of fatty liver and injury following EtOH withdrawal.
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Affiliation(s)
- Paul G. Thomes
- 1The Liver Study Unit, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska,2Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Karuna Rasineni
- 1The Liver Study Unit, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska,2Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska
| | - Li Yang
- 7Departmentof Internal Medicine, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Terrence M. Donohue
- 1The Liver Study Unit, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska,2Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,3Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska,4Pathology and Microbiology; College of Medicine; University of Nebraska Medical Center, Omaha, Nebraska,5The Center for Environmental Toxicology; College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska
| | - Jacy L. Kubik
- 1The Liver Study Unit, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska
| | - Mark A. McNiven
- 6Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Carol A. Casey
- 1The Liver Study Unit, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, Nebraska,2Department of Internal Medicine, University of Nebraska Medical Center, Omaha, Nebraska,3Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska
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6
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Davies SP, Reynolds GM, Stamataki Z. Clearance of Apoptotic Cells by Tissue Epithelia: A Putative Role for Hepatocytes in Liver Efferocytosis. Front Immunol 2018; 9:44. [PMID: 29422896 PMCID: PMC5790054 DOI: 10.3389/fimmu.2018.00044] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/08/2018] [Indexed: 12/11/2022] Open
Abstract
Toxic substances and microbial or food-derived antigens continuously challenge the liver, which is tasked with their safe neutralization. This vital organ is also important for the removal of apoptotic immune cells during inflammation and has been previously described as a “graveyard” for dying lymphocytes. The clearance of apoptotic and necrotic cells is known as efferocytosis and is a critical liver function to maintain tissue homeostasis. Much of the research into this form of immunological control has focused on Kupffer cells, the liver-resident macrophages. However, hepatocytes (and other liver resident cells) are competent efferocytes and comprise 80% of the liver mass. Little is known regarding the mechanisms of apoptotic and necrotic cell capture by epithelia, which lack key receptors that mediate phagocytosis in macrophages. Herein, we discuss recent developments that increased our understanding of efferocytosis in tissues, with a special focus on the liver parenchyma. We discuss the impact of efferocytosis in health and in inflammation, highlighting the role of phagocytic epithelia.
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Affiliation(s)
- Scott P Davies
- Centre for Liver Research, College of Medical and Dental Sciences, Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
| | - Gary M Reynolds
- Centre for Liver Research, College of Medical and Dental Sciences, Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom.,Centre for Liver Research and National Institute for Health Research (NIHR) Birmingham Liver Biomedical Research Unit, College of Medical and Dental Sciences, Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom.,University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - Zania Stamataki
- Centre for Liver Research, College of Medical and Dental Sciences, Institute for Immunology and Immunotherapy, University of Birmingham, Birmingham, United Kingdom
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7
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Willoughby JLS, Chan A, Sehgal A, Butler JS, Nair JK, Racie T, Shulga-Morskaya S, Nguyen T, Qian K, Yucius K, Charisse K, van Berkel TJC, Manoharan M, Rajeev KG, Maier MA, Jadhav V, Zimmermann TS. Evaluation of GalNAc-siRNA Conjugate Activity in Pre-clinical Animal Models with Reduced Asialoglycoprotein Receptor Expression. Mol Ther 2017; 26:105-114. [PMID: 28988716 PMCID: PMC5762979 DOI: 10.1016/j.ymthe.2017.08.019] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 02/04/2023] Open
Abstract
The hepatocyte-specific asialoglycoprotein receptor (ASGPR) is an ideal candidate for targeted drug delivery to the liver due to its high capacity for substrate clearance from circulation together with its well-conserved expression and function across species. The development of GalNAc-siRNA conjugates, in which a synthetic triantennary N-acetylgalactosamine-based ligand is conjugated to chemically modified siRNA, has enabled efficient, ASGPR-mediated delivery to hepatocytes. To investigate the potential impact of variations in receptor expression on the efficiency of GalNAc-siRNA conjugate delivery, we evaluated the pharmacokinetics and pharmacodynamics of GalNAc-siRNA conjugates in multiple pre-clinical models with reduced receptor expression. Despite greater than 50% reduction in ASGPR levels, GalNAc conjugate activity was retained, suggesting that the remaining receptor capacity was sufficient to mediate efficient uptake of potent GalNAc-siRNAs at pharmacologically relevant dose levels. Collectively, our data support a broad application of the GalNAc-siRNA technology for hepatic targeting, including disease states where ASGPR expression may be reduced.
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Affiliation(s)
| | - Amy Chan
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Alfica Sehgal
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Tim Racie
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | - Tuyen Nguyen
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | - Kun Qian
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
| | | | | | - Theo J C van Berkel
- Division of Biopharmaceutics, Leiden Academic Center for Drug Research, 2300 RA Leiden, the Netherlands
| | | | | | | | - Vasant Jadhav
- Alnylam Pharmaceuticals, Inc., Cambridge, MA 02142, USA
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8
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Mohr AM, Gould JJ, Kubik JL, Talmon GA, Casey CA, Thomas P, Tuma DJ, McVicker BL. Enhanced colorectal cancer metastases in the alcohol-injured liver. Clin Exp Metastasis 2017; 34:171-184. [PMID: 28168393 DOI: 10.1007/s10585-017-9838-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 01/16/2017] [Indexed: 02/08/2023]
Abstract
Metastatic liver disease is a major cause of mortality in colorectal cancer (CRC) patients. Alcohol consumption is a noted risk factor for secondary cancers yet the role of alcoholic liver disease (ALD) in colorectal liver metastases (CRLM) is not defined. This work evaluated tumor cell colonization in the alcoholic host liver using a novel preclinical model of human CRC liver metastases. Immunocompromised Rag1-deficient mice were fed either ethanol (E) or isocaloric control (C) diets for 4 weeks prior to intrasplenic injection of LS174T human CRC cells. ALD and CRLM were evaluated 3 or 5 weeks post-LS174T cell injection with continued C/E diet administration. ALD was confirmed by increased serum transaminases, hepatic steatosis and expression of cytochrome P4502E1, a major ethanol-metabolizing enzyme. Alcohol-mediated liver dysfunction was validated by impaired endocytosis of asialoorosomucoid and carcinoembryonic antigen (CEA), indicators of hepatocellular injury and progressive CRC disease, respectively. Strikingly, the rate and burden of CRLM was distinctly enhanced in alcoholic livers with metastases observed earlier and more severely in E-fed mice. Further, alcohol-related increases (1.5-3.0 fold) were observed in the expression of hepatic cytokines (TNF-α, IL-1 beta, IL-6, IL-10) and other factors noted to be involved in the colonization of CRC cells including ICAM-1, CCL-2, CCL-7, MMP-2, and MMP-9. Also, alcoholic liver injury was associated with altered hepatic localization as well as increased circulating levels of CEA released from CRC cells. Altogether, these findings indicate that the alcoholic liver provides a permissive environment for the establishment of CRLM, possibly through CEA-related inflammatory mechanisms.
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Affiliation(s)
- Ashley M Mohr
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - John J Gould
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA
| | - Jacy L Kubik
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA.,Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Geoffrey A Talmon
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Carol A Casey
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA.,Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Peter Thomas
- Department of Surgery and Biomedical Sciences, Creighton University, Omaha, NE, USA
| | - Dean J Tuma
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
| | - Benita L McVicker
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE, USA. .,Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
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9
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Petrosyan A, Cheng PW, Clemens DL, Casey CA. Downregulation of the small GTPase SAR1A: a key event underlying alcohol-induced Golgi fragmentation in hepatocytes. Sci Rep 2015; 5:17127. [PMID: 26607390 PMCID: PMC4660820 DOI: 10.1038/srep17127] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/26/2015] [Indexed: 12/14/2022] Open
Abstract
The hepatic asialoglycoprotein receptor (ASGP-R) is posttranslationally modified in the Golgi en route to the plasma membrane, where it mediates clearance of desialylated serum glycoproteins. It is known that content of plasma membrane-associated ASGP-R is decreased after ethanol exposure, although the mechanisms remain elusive. Previously, we found that formation of compact Golgi requires dimerization of the largest Golgi matrix protein giantin. We hypothesize that ethanol-impaired giantin function may be related to altered trafficking of ASGP-R. Here we report that in HepG2 cells expressing alcohol dehydrogenase and hepatocytes of ethanol-fed rats, ethanol metabolism results in Golgi disorganization. This process is initiated by dysfunction of SAR1A GTPase followed by altered COPII vesicle formation and impaired Golgi delivery of the protein disulfide isomerase A3 (PDIA3), an enzyme that catalyzes giantin dimerization. Additionally, we show that SAR1A gene silencing in hepatocytes mimics the effect of ethanol: dedimerization of giantin, arresting PDIA3 in the endoplasmic reticulum (ER) and large-scale alterations in Golgi architecture. Ethanol-induced Golgi fission has no effect on ER-to-Golgi transportation of ASGP-R, however, it results in its deposition in cis-medial-, but not trans-Golgi. Thus, alcohol-induced deficiency in COPII vesicle formation predetermines Golgi fragmentation which, in turn, compromises the Golgi-to-plasma membrane transportation of ASGP-R.
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Affiliation(s)
- Armen Petrosyan
- Department of Biochemistry and Molecular Biology, College of Medicine, Omaha, NE, USA
| | - Pi-Wan Cheng
- Department of Biochemistry and Molecular Biology, College of Medicine, Omaha, NE, USA
- Nebraska Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Dahn L. Clemens
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
- Nebraska Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
| | - Carol A. Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA
- Nebraska Western Iowa Health Care System, VA Service, Department of Research Service, Omaha, NE, USA
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10
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Crispe IN. APC licensing and CD4+T cell help in liver-stage malaria. Front Microbiol 2014; 5:617. [PMID: 25426113 PMCID: PMC4227505 DOI: 10.3389/fmicb.2014.00617] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 10/29/2014] [Indexed: 11/13/2022] Open
Abstract
Malaria parasites spend a critical phase of their life cycle inside hepatocytes, in an environment with complex and distinctive immunological features. Here I will discuss how the immunological features of the liver and the adaptations of malaria parasites interact, resulting in defective CD8+ T cell immunity. These processes are explored with a focus on the mechanism by which CD4+ T cells deliver help to CD8+ T cells, and specifically through their interaction with antigen-presenting cells (APCs), resulting in “licensing” of the APCs and enhanced capacity to optimally activate CD8+ T cells. Synthesis of the available evidence supports a model in which the parasite-mediated manipulation of programmed cell death in infected hepatocytes impairs the capacity of the liver’s immune system to successfully license APCs and fully activate T cell immunity.
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Affiliation(s)
- Ian N Crispe
- Department of Pathology, University of Washington Seattle, WA, USA
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11
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McVicker BL, Thiele GM, Casey CA, Osna NA, Tuma DJ. Susceptibility to T cell-mediated liver injury is enhanced in asialoglycoprotein receptor-deficient mice. Int Immunopharmacol 2013; 16:17-26. [PMID: 23538026 DOI: 10.1016/j.intimp.2013.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 02/05/2013] [Accepted: 03/13/2013] [Indexed: 02/05/2023]
Abstract
T cell activation and associated pro-inflammatory cytokine production is a pathological feature of inflammatory liver disease. It is also known that liver injury is associated with marked impairments in the function of many hepatic proteins including a hepatocyte-specific binding protein, the asialoglycoprotein receptor (ASGPR). Recently, it has been suggested that hepatic ASGPRs may play an important role in the physiological regulation of T lymphocytes, leading to our hypothesis that ASGPR defects correlate with inflammatory-mediated events in liver diseases. Therefore, in this study we investigated whether changes in hepatocellular ASGPR expression were related to the dysregulation of intrahepatic T lymphocytes and correlate with the development of T-cell mediated hepatitis. Mice lacking functional ASGPRs (receptor-deficient, RD), and wild-type (WT) controls were intravenously injected with T-cell mitogens, Concanavalin A (Con A) or anti-CD3 antibody. As a result of T cell mitogen treatment, RD mice lacking hepatic ASGPRs displayed enhancements in liver pathology, transaminase activities, proinflammatory cytokine expression, and caspase activation compared to that observed in normal WT mice. Furthermore, FACS analysis demonstrated that T-cell mitogen administration resulted in a significant rise in the percentage of CD8+ lymphocytes present in the livers of RD animals versus WT mice. Since these two mouse strains differ only in whether they express the hepatic ASGPR, it can be concluded that proper ASGPR function exerts a protective effect against T cell mediated hepatitis and that impairments to this hepatic receptor could be related to the accumulation of cytotoxic T cells that are observed in inflammatory liver diseases.
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Affiliation(s)
- Benita L McVicker
- Research Service (151), VA Nebraska-Western Iowa Health Care System, Omaha, NE 68105, United States.
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12
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Thomes PG, Trambly CS, Thiele GM, Duryee MJ, Fox HS, Haorah J, Donohue TM. Proteasome activity and autophagosome content in liver are reciprocally regulated by ethanol treatment. Biochem Biophys Res Commun 2011; 417:262-7. [PMID: 22142844 DOI: 10.1016/j.bbrc.2011.11.097] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 11/18/2011] [Indexed: 12/20/2022]
Abstract
UNLABELLED The proteasome and autophagy are two major intracellular protein degradation pathways and the regulation of each by ethanol metabolism affects cellular integrity. Using acute and chronic ethanol feeding to mice in vivo, and precision-cut rat liver slices (PCLS) ex vivo, we examined whether ethanol treatment altered these proteolytic pathways. In acute studies, we gave C57Bl/6 mice either ethanol or phosphate-buffered saline (PBS) by gastric intubation and sacrificed them 12h later. PCLS were exposed to 0 or 50mM ethanol for 12 and 24h with or without 4-methylpyrazole (4MP). In chronic studies we pair-fed control and ethanol liquid diets for 4-6 weeks to transgenic mice, expressing the green fluorescent protein (GFP) fused to the autophagic marker, microtubule associated protein-1 light chain 3 (LC3). Acute ethanol administration elevated autophagosomes (AVs), as judged by a 1.5-fold increase in LC3II content over PBS-gavaged control mice. Hepatic proteasome activity was unaffected by this treatment. Compared with controls, ethanol exposure for 12 and 24h to PCLS inhibited proteasome activity by 1.5- to 3-fold and simultaneously enhanced AVs by 2- to 5-fold. The decrease in proteasome activity and the rise in AVs both depended on ethanol oxidation as its inhibition by 4-methylpyrazole (4MP) blocked both proteasome inhibition and AV induction. Hepatocytes from mice chronically consuming ethanol exhibited a 1.6-fold decline in proteasome activity, and a 4-fold rise in GFP-LC3 puncta compared with pair-fed control mice. When we exposed hepatocytes from these animals to MG262, a proteasome inhibitor, LC3II puncta per cell further increased 2- to 5-fold over untreated cells. CONCLUSION Our findings demonstrate that ethanol metabolism generates oxidants, the levels of which differentially influence the activities of the proteasome and autophagy.
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Affiliation(s)
- Paul G Thomes
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68105, United States.
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Abstract
The Ashwell-Morell receptor (AMR) of hepatocytes, originally termed the hepatic asialoglycoprotein receptor, was the first cellular receptor to be identified and isolated and the first lectin to be detected in mammals. It is one of the multiple lectins of the C-type lectin family involved in recognition, binding, and clearance of asialoglycoproteins. We recently identified endogenous ligands of the AMR as desialylated prothrombotic components, including platelets and von Willebrand Factor [Ellies L. G., Ditto D., Levy G. G., Wahrenbrock M., Ginsburg D., Varki A., Le D. T., and Marth J. D. (2002). Sialyltransferase ST3Gal-IV operates as a dominant modifier of hemostasis by concealing asialoglycoprotein receptor ligands. Proc. Natl. Acad. Sci. USA 99: pp. 10042-10047; Grewal, P. K. Uchiyama, S., Ditto, D., Varki, N., Le, D. T., Nizet, V., Marth, J. D. (2008). The Ashwell receptor mitigates the lethal coagulopathy of sepsis. Nat. Medicine 14, pp. 648-655]. Among these components, clearance by the liver's AMR is enhanced by exposure of terminal galactose on the glycan chains. A physiological role for engaging the AMR in rapid clearance was identified as mitigating disseminating intravascular coagulopathy in sepsis to promote survival. This chapter overviews the endogenous ligands of the AMR as components of the coagulatory system, describes clearance mechanisms of the liver, and details hematology and coagulation assays used in mouse coagulation studies.
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Lee SML, Casey CA, McVicker BL. Impact of asialoglycoprotein receptor deficiency on the development of liver injury. World J Gastroenterol 2009; 15:1194-200. [PMID: 19291819 PMCID: PMC2658848 DOI: 10.3748/wjg.15.1194] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 01/06/2009] [Accepted: 01/13/2009] [Indexed: 02/06/2023] Open
Abstract
The asialoglycoprotein (ASGP) receptor is a well-characterized hepatic receptor that is recycled via the common cellular process of receptor-mediated endocytosis (RME). The RME process plays an integral part in the proper trafficking and routing of receptors and ligands in the healthy cell. Thus, the mis-sorting or altered transport of proteins during RME is thought to play a role in several diseases associated with hepatocyte and liver dysfunction. Previously, we examined in detail alterations that occur in hepatocellular RME and associated receptor functions as a result of one particular liver injury, alcoholic liver disease (ALD). The studies revealed profound ethanol-mediated impairments to the ASGP receptor and the RME process, indicating the importance of this receptor and the maintenance of proper endocytic events in normal tissue. To further clarify these observations, studies were performed utilizing knockout mice (lacking a functional ASGP receptor) to which were administered several liver toxicants. In addition to alcohol, we examined the effects following administration of anti-Fas (CD95) antibody, carbon tetrachloride (CCl(4)) and lipopolysaccharide (LPS)/galactosamine. The results of these studies demonstrated that the knockout mice sustained enhanced liver injury in response to all of the treatments, as shown by increased indices of liver damage, such as enhancement of serum enzyme levels, histopathological scores, as well as hepatocellular death. Overall, the work completed to date suggests a possible link between hepatic receptors and liver injury. In particular, adequate function and content of the ASGP receptor may provide protection against various toxin-mediated liver diseases.
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Casey CA, Lee SML, Aziz-Seible R, McVicker BL. Impaired receptor-mediated endocytosis: its role in alcohol-induced apoptosis. J Gastroenterol Hepatol 2008; 23 Suppl 1:S46-9. [PMID: 18336663 DOI: 10.1111/j.1440-1746.2007.05275.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Hepatocyte apoptosis, inflammation, and fibrosis are prominent features of liver disease in general and of alcoholic liver injury in particular. Although the link between these processes remains unclear, one universal characteristic of liver injury is the induction of hepatocellular damage, which results in the generation of apoptotic bodies. Work from our laboratory over the last several years has studied the effect of ethanol administration on the process of apoptosis and a role for altered endocytosis in alcoholic apoptosis. We initially focused our research on the hepatocyte by examining endocytosis using the asialoglycoprotein receptor (ASGP-R) pathway as a model and we identified multiple ethanol-induced impairments in receptor function. We also showed that uptake of apoptotic bodies is impaired in hepatocytes isolated from ethanol-fed animals compared to controls, and that this impairment is linked to altered ASGP-R function. Recent work from our laboratory is examining a link between ethanol-impaired ASGP-R function, apoptotic body accumulation, and inflammation in the liver. We are particularly interested in data showing that factors produced by Kupffer cells incubated with apoptotic bodies can lead to production of tumor necrosis factor-alpha and interleukin-6, and that this effect is exacerbated in the setting of alcohol administration. In addition, we have preliminary data showing that media from Kupffer cell cultures incubated with apoptotic bodies can induce hepatocyte killing. The goal of our future work is to show that inadequate removal of apoptotic cells, in part via altered receptor-mediated endocytosis, plays a role in the course of pathogenesis of alcoholic liver injury.
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Affiliation(s)
- Carol A Casey
- Department of Veterans Affairs Medical Center, University of Nebraska Medical Center, Omaha, Nebraska 68105, USA.
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Abstract
Liver fibrosis is caused by many chronic diseases. Liver injury results in activation of collagen-producing cells and excessive deposition of extracellular matrix proteins. This process is orchestrated by many cell types. Hepatocytes apoptosis and inflammatory cells trigger secretion of profibrogenic and proinflammatory cytokines, such as transforming growth factor-beta1, angiotensin II, leptin, which in turn activates hepatic stellate cells, the major source of collagen type I. This review is focused on recent progress in the study of the pathogenesis of liver fibrosis.
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17
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Tang N, He M, O’Riordan MA, Farkas C, Buck K, Lemmon V, Bearer CF. Ethanol inhibits L1 cell adhesion molecule activation of mitogen-activated protein kinases. J Neurochem 2006; 96:1480-90. [PMID: 16478533 PMCID: PMC4362514 DOI: 10.1111/j.1471-4159.2006.03649.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Inhibition of the functions of L1 cell adhesion molecule (L1) by ethanol has been implicated in the pathogenesis of the neurodevelopmental aspects of the fetal alcohol syndrome (FAS). Ethanol at pharmacological concentrations has been shown to inhibit L1-mediated neurite outgrowth of rat post-natal day 6 cerebellar granule cells (CGN). Extracellular signal-related kinases (ERK) 1/2 activation occurs following L1 clustering. Reduction in phosphoERK1/2 by inhibition of mitogen-activated protein kinase kinase (MEK) reduces neurite outgrowth of cerebellar neurons. Here, we examine the effects of ethanol on L1 activation of ERK1/2, and whether this activation occurs via activation of fibroblast growth factor receptor 1 (FGFR1). Ethanol at 25 mm markedly inhibited ERK1/2 activation by both clustering L1 with cross-linked monoclonal antibodies, or by L1-Fc chimeric proteins. Clustering L1 with subsequent ERK1/2 activation did not result in tyrosine phosphorylation of the FGFR1. In addition, inhibition of FGFR1 tyrosine kinase blocked basic fibroblast growth factor (bFGF) activation of ERK1/2, but did not affect activation of ERK1/2 by clustered L1. We conclude that ethanol disrupts the signaling pathway between L1 clustering and ERK1/2 activation, and that this occurs independently of the FGFR1 pathway in cerebellar granule cells.
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Affiliation(s)
- Ningfeng Tang
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Min He
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mary Ann O’Riordan
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Chloe Farkas
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Kevin Buck
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
| | - Vance Lemmon
- The Miami Project to Cure Paralysis, University of Miami School of Medicine, Miami, Florida, USA
| | - Cynthia F. Bearer
- Department of Pediatrics, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio, USA
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Lin L, Ye Y, Zakeri Z. p53, Apaf-1, caspase-3, and -9 are dispensable for Cdk5 activation during cell death. Cell Death Differ 2005; 13:141-50. [PMID: 16021178 DOI: 10.1038/sj.cdd.4401717] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Cyclin-dependent kinase 5 (Cdk5) is a member of the cyclin-dependent kinase family that is mostly seen in neurons, does not vary with cell cycle, and is activated in many neurodegenerative disorders and other non-neuronal pathologies, but its relationship to non-neuronal apoptosis is not understood, nor is the control of the activation of Cdk5 by its activators. The most widely studied activator of Cdk5, p35, is cleaved to p25 by calpain, an event that has been linked with activation of Cdk5 and neuronal death. Here we report that calpain-mediated Cdk5/p25 activation accompanies non-neuronal as well as neuronal cell death, suggesting that the p35/calpain/p25/Cdk5 activation sequence is a general feature of cell death. We further demonstrate that Cdk5 can be activated in the absence of p53, Apaf-1, caspase-9, and -3 during cell death, indicating that its activation relates more to cell death than to a specific pathway of apoptosis.
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Affiliation(s)
- L Lin
- Department of Biology, Queens College and Graduate Center of the City University of New York, 65-30 Kissena Blvd, Flushing, NY 11367, USA
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