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Szentirmai E, Buckley K, Massie AR, Kapas L. Lipopolysaccharide-Mediated Effects of the Microbiota on Sleep and Body Temperature. RESEARCH SQUARE 2024:rs.3.rs-3995260. [PMID: 38496422 PMCID: PMC10942547 DOI: 10.21203/rs.3.rs-3995260/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Background Recent research suggests that microbial molecules translocated from the intestinal lumen into the host's internal environment may play a role in various physiological functions, including sleep. Previously, we identified that butyrate, a short-chain fatty acid, produced by intestinal bacteria, and lipoteichoic acid, a cell wall component of gram-positive bacteria induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Building upon these findings, we aimed to explore the sleep signaling potential of intraportally administered lipopolysaccharide, a primary component of gram-negative bacterial cell walls, in rats. Results Low dose of lipopolysaccharide (1 μg/kg) increased sleep duration and prolonged fever, without affecting systemic lipopolysaccharide levels. Interestingly, administering LPS systemically outside the portal region at a dose 20 times higher did not affect sleep, indicating a localized sensitivity within the hepatoportal region, encompassing the portal vein and liver, for the sleep and febrile effects of lipopolysaccharide. Furthermore, both the sleep- and fever-inducing effects of LPS were inhibited by indomethacin, a prostaglandin synthesis inhibitor, and replicated by intraportal administration of prostaglandin E2 or arachidonic acid, suggesting the involvement of the prostaglandin system in mediating these actions. Conclusions These findings underscore the dynamic influence of lipopolysaccharide in the hepatoportal region on sleep and fever mechanisms, contributing to a complex microbial molecular assembly that orchestrates communication between the intestinal microbiota and brain. Lipopolysaccharide is a physiological component of plasma in both the portal and extra-portal circulation, with its levels rising in response to everyday challenges like high-fat meals, moderate alcohol intake, sleep loss and psychological stress. The increased translocation of lipopolysaccharide under such conditions may account for their physiological impact in daily life, highlighting the intricate interplay between microbial molecules and host physiology.
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Rani R, Gandhi CR. Stellate cell in hepatic inflammation and acute injury. J Cell Physiol 2023; 238:1226-1236. [PMID: 37120832 DOI: 10.1002/jcp.31029] [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: 03/27/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 05/02/2023]
Abstract
The perisinusoidal hepatic stellate cells (HSCs) have been investigated extensively for their role as the major fibrogenic cells during chronic liver injury. HSCs also produce numerous cytokines, chemokines, and growth mediators, and express cell adhesion molecules constitutively and in response to stimulants such as endotoxin (lipopolysaccharide). With this property and by interacting with resident and recruited immune and inflammatory cells, HSCs regulate hepatic immune homeostasis, inflammation, and acute injury. Indeed, experiments with HSC-depleted animal models and cocultures have provided evidence for the prominent role of HSCs in the initiation and progression of inflammation and acute liver damage due to various toxic agents. Thus HSCs and/or mediators derived thereof during acute liver damage may be considered as potential therapeutic targets.
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Affiliation(s)
- Richa Rani
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Research & Development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio, USA
| | - Chandrashekhar R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
- Research & Development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio, USA
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA
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3
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Zhang J, Zao X, Zhang J, Guo Z, Jin Q, Chen G, Gan D, Du H, Ye Y. Is it possible to intervene early cirrhosis by targeting toll-like receptors to rebalance the intestinal microbiome? Int Immunopharmacol 2023; 115:109627. [PMID: 36577151 DOI: 10.1016/j.intimp.2022.109627] [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: 11/01/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 12/27/2022]
Abstract
Cirrhosis is a progressive chronic liver disease caused by one or more causes and characterized by diffuse fibrosis, pseudolobules, and regenerated nodules. Once progression to hepatic decompensation, the function of the liver and other organs is impaired and almost impossible to reverse and recover, which often results in hospitalization, impaired quality of life, and high mortality. However, in the early stage of cirrhosis, there seems to be a possibility of cirrhosis reversal. The development of cirrhosis is related to the intestinal microbiota and activation of toll-like receptors (TLRs) pathways, which could regulate cell proliferation, apoptosis, expression of the hepatomitogen epiregulin, and liver inflammation. Targeting regulation of intestinal microbiota and TLRs pathways could affect the occurrence and development of cirrhosis and its complications. In this paper, we first reviewed the dynamic change of intestinal microbiota and TLRs during cirrhosis progression. And further discussed the interaction between them and potential therapeutic targets to reverse early staged cirrhosis.
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Affiliation(s)
- Jiaxin Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China
| | - Xiaobin Zao
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China
| | - Jiaying Zhang
- School of Mechanical Engineering and Automation, Beihang University, Beijing, China
| | - Ziwei Guo
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Qian Jin
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Guang Chen
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China
| | - Da'nan Gan
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China
| | - Hongbo Du
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China
| | - Yong'an Ye
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing, China; Institute of Liver Diseases, Beijing University of Chinese Medicine, Beijing, China.
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Rani R, Sharma A, Wang J, Kumar S, Polaki US, Gandhi CR. Endotoxin-Stimulated Hepatic Stellate Cells Augment Acetaminophen-Induced Hepatocyte Injury. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:518-535. [PMID: 34954210 PMCID: PMC8895430 DOI: 10.1016/j.ajpath.2021.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 10/27/2021] [Accepted: 11/29/2021] [Indexed: 12/11/2022]
Abstract
Acetaminophen (APAP)-induced liver injury is influenced by inflammatory Gram-negative bacterial endotoxin [lipopolysaccharide (LPS)], mechanisms of which are not completely understood. Because LPS-stimulated perisinusoidal hepatic stellate cells (HSCs) produce cytokines that affect survival of hepatocytes, this study investigated their role in APAP-induced liver injury. Fed (nonstarved) rats were administered 5 mg/kg LPS or phosphate-buffered saline (PBS) vehicle, followed by 200 mg/kg APAP or PBS an hour later, and euthanized at 6 hours. Control rats received PBS at both time points. Both LPS and APAP caused mild hepatocyte injury (apoptosis), as assessed by histopathology, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining, and caspase-3 activation. The liver injury was augmented in rats administered LPS + APAP, in association with increased nuclear translocation of interferon-regulatory factor-1 (IRF1). In vitro, APAP augmented LPS/HSC-conditioned medium-induced inhibition of DNA and protein synthesis, apoptosis, and nuclear IRF1 in hepatocytes. LPS-stimulated HSCs produced interferon-β (IFN-β), and LPS/HSC + APAP-induced hepatocyte apoptosis was inhibited by anti-IFN-β antibody. Finally, HSC-depleted mice produced significantly lower IFN-β and tumor necrosis factor-α, exhibited less oxidative stress, and were protected from excessive injury due to high APAP dose (600 mg/kg), as well as LPS (5 mg/kg overnight) followed by APAP. In co-culture with or without LPS, HSCs increased expression of proinflammatory cytokines by Kupffer cells. These results suggest that HSCs play a critical role in APAP-induced liver injury without or with LPS preconditioning, and it involves INF-β-IRF1 signaling.
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Affiliation(s)
- Richa Rani
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Akanksha Sharma
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology, University of Cincinnati, Cincinnati, Ohio
| | - Sudhir Kumar
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Usha S Polaki
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio
| | - Chandrashekhar R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Research & development, Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.
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Ehlting C, Wolf SD, Bode JG. Acute-phase protein synthesis: a key feature of innate immune functions of the liver. Biol Chem 2021; 402:1129-1145. [PMID: 34323429 DOI: 10.1515/hsz-2021-0209] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/15/2021] [Indexed: 01/08/2023]
Abstract
The expression of acute-phase proteins (APP's) maintains homeostasis and tissue repair, but also represents a central component of the organism's defense strategy, especially in the context of innate immunity. Accordingly, an inflammatory response is accompanied by significant changes in the serum protein composition, an aspect that is also used diagnostically. As the main site of APP synthesis the liver is constantly exposed to antigens or pathogens via blood flow, but also to systemic inflammatory signals originating either from the splanchnic area or from the circulation. Under both homeostatic and acute-phase response (APR) conditions the composition of APP's is determined by the pattern of regulatory mediators derived from the systemic circulation or from local cell populations, especially liver macrophages. The key regulators mentioned here most frequently are IL-1β, IL-6 and TNF-α. In addition to a variety of molecular mediators described mainly on the basis of in vitro studies, recent data emphasize the in vivo relevance of cellular key effectors as well as molecular key mediators and protein modifications for the regulation and function of APP's. These are aspects, on which the present review is primarily focused.
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Affiliation(s)
- Christian Ehlting
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Hospital of the Heinrich-Heine-University, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Stephanie D Wolf
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Hospital of the Heinrich-Heine-University, Moorenstrasse 5, D-40225 Düsseldorf, Germany
| | - Johannes G Bode
- Clinic for Gastroenterology, Hepatology and Infectious Diseases, Hospital of the Heinrich-Heine-University, Moorenstrasse 5, D-40225 Düsseldorf, Germany
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Sharma A, Verma AK, Kofron M, Kudira R, Miethke A, Wu T, Wang J, Gandhi CR. Lipopolysaccharide Reverses Hepatic Stellate Cell Activation Through Modulation of cMyb, Small Mothers Against Decapentaplegic, and CCAAT/Enhancer-Binding Protein C/EBP Transcription Factors. Hepatology 2020; 72:1800-1818. [PMID: 32064648 PMCID: PMC8009050 DOI: 10.1002/hep.31188] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 01/26/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIMS During liver injury, quiescent hepatic stellate cells (qHSCs) transdifferentiate into proliferative and fibrogenic activated myofibroblastic phenotype (activated hepatic stellate cell; aHSCs) expressing smooth muscle α-actin (αSMA) and platelet-derived growth factor beta receptor (PDGFβR). Their interactions with gut-derived bacterial lipopolysaccharide (LPS) are implicated in hepatic fibrogenesis. However, LPS can also attenuate fibrogenic characteristics of aHSCs. APPROACH AND RESULTS We examined molecular mechanisms of antifibrogenic effects of LPS on aHSCs in vitro and in vivo. Culture-activated rat HSCs were exposed to 0-100 ng/mL of LPS or its active component, diphosphoryl-lipid A (DPLA), and parameters of fibrosis and inflammatory cytokines/chemokines were determined by qRT-PCR, western, and immunohistochemical analyses. In vivo, HSCs were activated by repeated CCl4 administration to rats every 3 days for 3 or 8 weeks, then challenged with LPS (5 mg/kg; IP). HSCs were isolated 24 hours later, and fibrogenic/inflammatory parameters were analyzed. LPS induced phenotypic changes in aHSCs (rounding, size reduction) and loss of proliferation. LPS down-regulated expression of αSMA, PDGFβR, transforming growth factor beta receptor 1 (TGFβR1), collagen 1α1 (Col1α1), and fibronectin while up-regulating tumor necrosis factor alpha, interleukin-6, and C-X-C motif chemokine ligand 1 expression. LPS did not increase peroxisome proliferation-activated receptor gamma expression or lipid accumulation typical of qHSCs. DPLA elicited the same effects as LPS on aHSCs, indicating specificity, and monophosphoryl lipid A down-regulated fibrogenic markers, but elicited very weak inflammatory response. LPS down-regulated the expression of cMyb, a transcription factor for αSMA, and up-regulated small mother against decapentaplegic (SMAD)7 and CCAAT/enhancer-binding protein (C/EBP)δ, the transcriptional inhibitors of Col1α1 expression. In vivo LPS treatment of aHSCs inhibited their proliferation, down-regulated PDGFβR, αSMA, TGFβR1, Col1α1, and cMyb expression, and increased expression of SMAD7, C/EBPα, and C/EBPδ. CONCLUSIONS In conclusion, LPS induces a unique phenotype in aHSCs associated with down-regulation of key fibrogenic mechanisms and thus may have an important role in limiting fibrosis.
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Affiliation(s)
- Akanksha Sharma
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH,Cincinnati VA Medical Center, Cincinnati, OH
| | - Alok K. Verma
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH,Cincinnati VA Medical Center, Cincinnati, OH
| | - Matthew Kofron
- Developmental Biology, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Ramesh Kudira
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Alexander Miethke
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, LA
| | - Jiang Wang
- Deparment of Pathology, University of Cincinnati, Cincinnati, OH
| | - Chandrashekhar R. Gandhi
- Division of Gastroenterology, Hepatology & Nutrition, Department of Pediatries, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH,Cincinnati VA Medical Center, Cincinnati, OH
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Guo X, Li W, An R, Huang M, Yu Z. Composite ammonium glycyrrhizin has hepatoprotective effects in chicken hepatocytes with lipopolysaccharide/enrofloxacin-induced injury. Exp Ther Med 2020; 20:52. [PMID: 32952642 PMCID: PMC7485299 DOI: 10.3892/etm.2020.9180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 05/17/2018] [Indexed: 11/06/2022] Open
Abstract
Composite ammonium glycyrrhizin (CAG) has anti-inflammatory activity. Lipopolysaccharide (LPS) and enrofloxacin (ENR) induce liver damage; however, the mechanism underlying LPS/ENR-induced hepatic injury remains to be elucidated. In the present study, the mechanism of LPS/ENR-induced liver injury was investigated in vitro and the protective effects of CAG were also evaluated. Primary chicken hepatocytes were isolated and a model of LPS/ENR-induced hepatocyte injury was established. mRNA and protein expression levels were evaluated by reverse transcription-quantitative polymerase chain reaction and western blot, respectively. LPS/ENR exposure significantly increased supernatant aspartate aminotransferase (AST) and alanine aminotransferase (ALT). In the LPS/ENR-treated group, glutathione (GSH) and the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities were significantly increased. Flow cytometry results revealed that the apoptotic rate significantly increased in the LPS/ENR-treated group compared with the control, while treatment with CAG given 24 h prior to LPS/ENR caused a significant decrease in the apoptotic rate compared with the model group. Furthermore, CAG treatment reversed LPS/ENR-associated alterations in the mRNA and protein expression of Caspase-3, apoptosis regulator Bcl-2 (Bcl-2) and Bcl-2 associated X-protein. The mitochondrial membrane potential significantly decreased and the mitochondrial microstructure was notably altered following exposure to LPS/ENR compared with the control. In conclusion, these results suggested that LPS/ENR-treated hepatocytes were damaged via apoptotic signaling pathways and CAG prevented LPS/ENR-induced hepatocyte injury.
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Affiliation(s)
- Xuewen Guo
- Department of Veterinary Preventive Medicine, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
| | - Wenyang Li
- Department of Veterinary Preventive Medicine, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
| | - Ran An
- Department of Veterinary Preventive Medicine, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
| | - Mei Huang
- Department of Veterinary Preventive Medicine, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
| | - Zugong Yu
- Department of Veterinary Preventive Medicine, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, P.R. China
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Gandhi CR. Pro- and Anti-fibrogenic Functions of Gram-Negative Bacterial Lipopolysaccharide in the Liver. Front Med (Lausanne) 2020; 7:130. [PMID: 32373617 PMCID: PMC7186417 DOI: 10.3389/fmed.2020.00130] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/24/2020] [Indexed: 12/14/2022] Open
Abstract
Extensive research performed over several decades has identified cells participating in the initiation and progression of fibrosis, and the numerous underlying inter- and intra-cellular signaling pathways. However, liver fibrosis continues to be a major clinical challenge as the precise targets of treatment are still elusive. Activation of physiologically quiescent perisinusoidal hepatic stellate cells (HSCs) to a myofibroblastic proliferating, contractile and fibrogenic phenotype is a critical event in the pathogenesis of chronic liver disease. Thus, elucidation of the mechanisms of the reversal to quiescence or inhibition of activated HSCs, and/or their elimination via apoptosis has been the focus of intense investigation. Lipopolysaccharide (LPS), a gut-resident Gram-negative bacterial endotoxin, is a powerful pro-inflammatory molecule implicated in hepatic injury, inflammation and fibrosis. In both acute and chronic liver injury, portal venous levels of LPS are elevated due to increased intestinal permeability. LPS, via CD14 and Toll-like receptor 4 (TLR4) and its adapter molecules, stimulates macrophages, neutrophils and several other cell types to produce inflammatory mediators as well as factors that can activate HSCs and stimulate their fibrogenic activity. LPS also stimulates synthesis of pro- and anti-inflammatory cytokines/chemokines, growth mediators and molecules of immune regulation by HSCs. However, LPS was found to arrest proliferation of activated HSCs and to convert them into non-fibrogenic phenotype. Interestingly, LPS can elicit responses in HSCs independent of CD14 and TLR4. Identifying and/or developing non-inflammatory but anti-fibrogenic mimetics of LPS could be relevant for treating liver fibrosis.
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Affiliation(s)
- Chandrashekhar R Gandhi
- Divisions of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.,Cincinnati VA Medical Center, Cincinnati, OH, United States
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Hu N, Wang C, Dai X, Zhou M, Gong L, Yu L, Peng C, Li Y. Phillygenin inhibits LPS-induced activation and inflammation of LX2 cells by TLR4/MyD88/NF-κB signaling pathway. JOURNAL OF ETHNOPHARMACOLOGY 2020; 248:112361. [PMID: 31683033 DOI: 10.1016/j.jep.2019.112361] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 10/12/2019] [Accepted: 10/26/2019] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The traditional Chinese medicine Forsythiae Fructus is the dried fruit of Forsythia suspensa (Thunb.) Vahl. It is commonly used to clear heat and detoxify, reduce swelling and disperse knot, and evacuate wind and heat. AIM OF THE STUDY Inflammation is involved in liver fibrosis. Phillygenin (PHI) is a kind of lignans extracted and separated from Forsythiae Fructus, which has been reported to have a good anti-inflammatory effect. Therefore, we aimed to explore whether PHI has a therapeutic effect on liver fibrosis caused by inflammation. MATERIALS AND METHODS Firstly, the induction of the LX2 cells inflammatory model and fibrosis model by LPS with different concentrations were studied. Then, high, medium and low doses PHI was given for intervention therapy. The secretion of IL-6, IL-1β and TNF-α inflammatory factors were detected by ELISA kit, and the expression of collagen I and α-SMA was detected by Western blot and RT-qPCR. The possible mechanism of PHI on TLR4/MyD88/NF-κB signal pathway was studied by computer-aided drug design software and the results were further verified by Western blot and RT-qPCR experiments. RESULTS The results showed that LPS could promote the expression of IL-6, IL-1β and TNF-α and the expression of collagen I and α-SMA, indicating that LPS could induce inflammation and fibrosis in LX2 cells. PHI could inhibit LX2 cell activation and fibrotic cytokine expression by inhibiting LPS-induced pro-inflammatory reaction. Molecular docking results showed that PHI could successfully dock with TLR4, MyD88, IKKβ, p65, IκBα, and TAK1 proteins. Subsequently, Western blot and qPCR results further proved that PHI could inhibit the proteins expression in TLR4/MyD88/NF-κB signal pathway which were consistent with the molecular docking results. CONCLUSION PHI can inhibit LPS-induced pro-inflammatory reaction and LX2 cell activation through TLR4/MyD88/NF-κB signaling pathway, thereby inhibiting liver fibrosis.
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Affiliation(s)
- Naihua Hu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Cheng Wang
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Xuyang Dai
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Mengting Zhou
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Lihong Gong
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Lingyuan Yu
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China
| | - Cheng Peng
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China.
| | - Yunxia Li
- School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Key Laboratory of Standardization for Chinese Herbal Medicine, Ministry of Education, National Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, Chengdu, 611137, China.
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10
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Choi WM, Kim MH, Jeong WI. Functions of hepatic non-parenchymal cells in alcoholic liver disease. LIVER RESEARCH 2019. [DOI: 10.1016/j.livres.2019.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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11
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Rani R, Kumar S, Sharma A, Mohanty SK, Donnelly B, Tiao GM, Gandhi CR. Mechanisms of concanavalin A-induced cytokine synthesis by hepatic stellate cells: Distinct roles of interferon regulatory factor-1 in liver injury. J Biol Chem 2018; 293:18466-18476. [PMID: 30348900 DOI: 10.1074/jbc.ra118.005583] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 10/15/2018] [Indexed: 12/26/2022] Open
Abstract
Mice depleted of hepatic stellate cells (HSCs) are protected from concanavalin A (ConA)-induced liver injury that is mediated by the activation of interferon regulatory factor 1 (IRF1). The aim of this study was to determine the mechanisms of ConA-mediated signaling and synthesis/release of mediators by HSCs that damage hepatocytes. Primary cultures of wildtype (WT) and IRF1-knockout (KO) HSCs and hepatocytes were used, and ConA-induced liver damage in interferon (IFN)αβ receptor-deficient (IFNαβR-KO) mice was determined. Specific binding of ConA to HSCs induced rapid activation of JAK2 and STAT1. ConA-induced expression of IRF1, IFNβ, tumor necrosis factor α, and CXCL1 was abrogated by selective inhibition of JAK2 and STAT1. Despite activating JAK2/STAT1, ConA failed to stimulate expression of inflammatory cytokines in HSCs from IRF1-KO mice. ConA-conditioned WT-HSC medium caused activation of JNK and caspase 3, and apoptosis of hepatocytes from WT but not from IRF1-KO or IFNαβR-KO mice. Conversely, ConA-conditioned medium of IRF1-KO HSCs failed to cause apoptosis of WT or IRF1-KO hepatocytes. IFNαβR-KO mice were protected from ConA-induced liver damage, and ConA-induced hepatic expression of IRF1 and pro-inflammatory cytokines and chemokines, and infiltration of neutrophils were significantly lower in IFNαβR-KO than in WT mice. These results demonstrate distinct roles of IRF1 in hepatic inflammation (HSCs) and injury (hepatocytes) and can be an important target for intervention in acute liver injury.
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Affiliation(s)
- Richa Rani
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229.,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and
| | - Sudhir Kumar
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229.,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and
| | - Akanksha Sharma
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Sujit K Mohanty
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Bryan Donnelly
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Gregory M Tiao
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Chandrashekhar R Gandhi
- From the Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, .,the Cincinnati Veterans Affairs Medical Center, Cincinnati, Ohio 45220 and.,the Department of Surgery, University of Cincinnati, Cincinnati, Ohio 45220
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12
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Li W, Li Y, Jiang X, Li X, Yu Z. Compound Ammonium Glycyrrhizin Protects Hepatocytes from Injury Induced by Lipopolysaccharide/Florfenicol through a Mitochondrial Pathway. Molecules 2018; 23:molecules23092378. [PMID: 30227687 PMCID: PMC6225407 DOI: 10.3390/molecules23092378] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 09/11/2018] [Accepted: 09/12/2018] [Indexed: 12/26/2022] Open
Abstract
Florfenicol (FFC), a widely used drug for chicken diseases, can aggravate lipopolysaccharide (LPS) damage to the liver. For this condition, natural or synthetic products displaying strong antioxidant capacity are expected to prevent LPS/FFC from inducing liver injury, so in our study, the compound ammonium glycyrrhizin (CAG) is used as the protective drug to decrease the injury to liver. The research aims to illustrate the underlying mechanism of combining LPS with FFC-induced liver injury and the protective role of CAG by using primary chicken hepatocytes as an in vitro model. The results show that LPS/FFC induced cell apoptosis and CAG protected hepatocytes from injury. The permeability of the cell membrane is elevated by LPS/FFC, leading to the efflux of enzymes (ALT, AST). Flow cytometry analysis indicates that LPS/FFC treatment increased the apoptosis rate significantly. Furthermore, with the up-regulation of apoptosis genes bax, cytochrome c and the down-regulation of bcl-2, caspase-3 and caspase-9 are activated at the gene level. LPS/FFC-induced mitochondrial damage is accompanied by a significant decrease in mitochondrial membrane potential (MMP) and severe mitochondrial damage. However, CAG improves the situation for the purpose of protecting the liver. In conclusion, it is speculated that LPS/FFC induces severe liver injury through apoptosis and the CAG protects hepatocytes from injury via the mitochondria-mediated apoptosis pathway.
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Affiliation(s)
- Wenyang Li
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Ying Li
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Xiangyuan Jiang
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Xiaohui Li
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Zugong Yu
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
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13
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Chen Y, Wu Z, Yuan B, Dong Y, Zhang L, Zeng Z. MicroRNA-146a-5p attenuates irradiation-induced and LPS-induced hepatic stellate cell activation and hepatocyte apoptosis through inhibition of TLR4 pathway. Cell Death Dis 2018; 9:22. [PMID: 29348414 PMCID: PMC5833436 DOI: 10.1038/s41419-017-0038-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 10/05/2017] [Accepted: 10/06/2017] [Indexed: 12/14/2022]
Abstract
Elevated toll-like receptor 4 (TLR4) expression is associated with a high risk of radiation-induced liver disease (RILD). MicroRNA (miR)-146a-5p is a key regulator of lipopolysaccharide (LPS)/TLR4 signaling, but its role in modulation of RILD remains unclear. Here, we found that irradiation and LPS stimulation induced TLR4 and miR-146a-5p expression in the human hepatic stellate cell (HSC) line LX2. Ectopic expression of miR-146a-5p in LX2 inhibited irradiation-induced and LPS-induced pro-inflammatory cytokine secretion and cell proliferation, and promoted cell apoptosis by down-regulating the expression levels of TLR4, interleukin-1 receptor associated kinase 1 (IRAK1), tumor necrosis factor receptor associated factor 6 (TRAF6) and phosphorylation of nuclear factor-kappa B. In addition, the culture medium from the irradiated and LPS-stimulated HSCs transfected with miR-146a-5p significantly attenuated apoptosis in irradiated hepatocytes. Overexpression of miR-146a-5p reduced α-smooth muscle actin production in irradiated and LPS-stimulated LX2 cells, which was associated with inhibition of TRAF6-mediated JNK and Smad2 phosphorylation. Knockdown of TRAF6 or IRAK1 mimicked the effects of miR-146a-5p on HSC function. Furthermore, miR-146a-5p treatment alleviated irradiation-induced and endotoxin-induced hepatic inflammatory response and fibrogenesis in mice through inhibition of the TLR4 signaling pathway. Collectively, this study reveals the anti-pro-inflammatory and anti-fibrotic effects of miR-146a-5p on liver injury, and suggests a potential application of miR-146a-5p in the therapeutic prevention of RILD.
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Affiliation(s)
- Yuhan Chen
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China
| | - Zhifeng Wu
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China
| | - Baoying Yuan
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China
| | - Yinying Dong
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China
| | - Li Zhang
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China
| | - Zhaochong Zeng
- Department of Radiation Oncology, Zhongshan Hospital, Fudan University, 180# Fenglin Road, 200032, Shanghai, China.
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14
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Vodovotz Y, Simmons RL, Gandhi CR, Barclay D, Jefferson BS, Huang C, Namas R, El-Dehaibi F, Mi Q, Billiar TR, Zamora R. "Thinking" vs. "Talking": Differential Autocrine Inflammatory Networks in Isolated Primary Hepatic Stellate Cells and Hepatocytes under Hypoxic Stress. Front Physiol 2017; 8:1104. [PMID: 29312006 PMCID: PMC5743931 DOI: 10.3389/fphys.2017.01104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/14/2017] [Indexed: 12/23/2022] Open
Abstract
We hypothesized that isolated primary mouse hepatic stellate cells (HSC) and hepatocytes (HC) would elaborate different inflammatory responses to hypoxia with or without reoxygenation. We further hypothesized that intracellular information processing (“thinking”) differs from extracellular information transfer (“talking”) in each of these two liver cell types. Finally, we hypothesized that the complexity of these autocrine responses might only be defined in the absence of other non-parenchymal cells or trafficking leukocytes. Accordingly, we assayed 19 inflammatory mediators in the cell culture media (CCM) and whole cell lysates (WCLs) of HSC and HC during hypoxia with and without reoxygenation. We applied a unique set of statistical and data-driven modeling techniques including Two-Way ANOVA, hierarchical clustering, Principal Component Analysis (PCA) and Network Analysis to define the inflammatory responses of these isolated cells to stress. HSC, under hypoxic and reoxygenation stresses, both expressed and secreted larger quantities of nearly all inflammatory mediators as compared to HC. These differential responses allowed for segregation of HSC from HC by hierarchical clustering. PCA suggested, and network analysis supported, the hypothesis that above a certain threshold of cellular stress, the inflammatory response becomes focused on a limited number of functions in both HSC and HC, but with distinct characteristics in each cell type. Network analysis of separate extracellular and intracellular inflammatory responses, as well as analysis of the combined data, also suggested the presence of more complex inflammatory “talking” (but not “thinking”) networks in HSC than in HC. This combined network analysis also suggested an interplay between intracellular and extracellular mediators in HSC under more conditions than that observed in HC, though both cell types exhibited a qualitatively similar phenotype under hypoxia/reoxygenation. Our results thus suggest that a stepwise series of computational and statistical analyses may help decipher how cells respond to environmental stresses, both within the cell and in its secretory products, even in the absence of cooperation from other cells in the liver.
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Affiliation(s)
- Yoram Vodovotz
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Richard L Simmons
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Derek Barclay
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | | | - Chao Huang
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Rami Namas
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Fayten El-Dehaibi
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Qi Mi
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Timothy R Billiar
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ruben Zamora
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA, United States.,Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Pittsburgh Liver Research Center, University of Pittsburgh, Pittsburgh, PA, United States
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15
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Rani R, Tandon A, Wang J, Kumar S, Gandhi CR. Stellate Cells Orchestrate Concanavalin A-Induced Acute Liver Damage. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2008-2019. [PMID: 28710903 DOI: 10.1016/j.ajpath.2017.05.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 05/13/2017] [Accepted: 05/22/2017] [Indexed: 12/12/2022]
Abstract
Concanavalin A (ConA) causes immune cell-mediated liver damage, but the contribution of resident nonparenchymal cells (NPCs) is also evident. Hepatic stellate cells (HSCs) induce hepatic inflammation and immunological reactions; we therefore investigated their role in ConA-induced liver injury. ConA was administered i.v. to control or HSC-depleted mice; hepatic histopathology and cytokines/chemokines were determined after 6 hours. In vitro, effects of ConA-conditioned HSC medium on hepatocytes were determined. ConA induced inflammation, sinusoidal congestion, and extensive midzonal hepatocyte death in control mice, which were strongly minimized in HSC-depleted mice. CD4 and natural killer T cells and neutrophils were markedly reduced in ConA-treated HSC-depleted mice compared with control mice. The increase in cytokines/chemokines of hepatic injury was much higher in ConA-treated control mice than in HSC-depleted mice. ConA-treated HSCs showed increased expression of interferon-β, tumor necrosis factor-α, and CXCL1, induced oxidative stress in hepatocytes, and caused hepatocyte apoptosis. ConA induced nuclear translocation of interferon-regulatory factor-1 (IRF1) in hepatocytes in vivo, and ConA/HSC induced a similar effect in cultured hepatocytes. IRF1-knockout mice were resistant to ConA-induced liver damage, and anti-interferon β antibody mitigated ConA/HSC-induced injury. In HSC-NPC co-culture, ConA-induced expression of inflammatory cytokines/chemokines was significantly augmented compared with NPCs alone. HSCs play an essential role in ConA-induced liver injury directly via the interferon-β/IRF1 axis, and by modulating properties of NPCs.
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Affiliation(s)
- Richa Rani
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Ashish Tandon
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio
| | - Jiang Wang
- Department of Pathology, University of Cincinnati, Cincinnati, Ohio
| | - Sudhir Kumar
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Chandrashekhar R Gandhi
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio; Cincinnati Veterans Administration Medical Center, Cincinnati, Ohio; Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
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16
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Lipopolysaccharides induce Smad2 phosphorylation through PI3K/Akt and MAPK cascades in HSC-T6 hepatic stellate cells. Life Sci 2017; 184:37-46. [PMID: 28689803 DOI: 10.1016/j.lfs.2017.07.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/30/2017] [Accepted: 07/05/2017] [Indexed: 01/22/2023]
Abstract
AIMS Endotoxemia and its pro-fibrogenic signaling play a significant role in the development of hepatic fibrosis. This study investigated whether lipopolysaccharide (LPS) directly activate cultured HSC-T6 hepatic stellate cells (HSCs) through triggering Smad-dependent pro-fibrogenic signaling pathway. MAIN METHODS Direct cell counting and assays for cell proliferation and migration were used to measure the effects of LPS on HSC behaviors. Quantitative PCR, Western blot, and gelatin zymography were used to quantify the molecular effects of LPS on expression of HSC activation markers and signaling activity. KEY FINDINGS Long-term exposure to LPS exhibited moderately stimulatory effect on HSC cell growth. A wound-healing cell migration assay showed that LPS suppressed HSC-T6 cell migration. qPCR and Western blotting detection indicated that LPS treatment induced upregulation of type I and IV collagens, α-smooth muscle actin (α-SMA), and matrix metalloproteinase-9 (MMP-9). Gelatin zymography confirmed that LPS elevated MMP-9, but not MMP-2 gelatinolytic activity. Moreover, LPS immediately stimulated Akt, EKR1/2, JNK, p38 MAPK, and Smad2 hyperphosphorylation, supporting that LPS directly triggers pro-fibrogenic Smad signaling cascade without TGF-β1 stimulation. Kinase blockade experiments demonstrated the involvement of PI3K/Akt, JNK, p38 MAPK, but not ERK1/2 signaling activation in the LPS-elicited Smad2 phosphorylation as well as the overexpression of type I collagen and α-SMA in HSC-T6 cells. SIGNIFICANCE These findings demonstrate that LPS exerts pro-fibrogenic effect through activation and transformation of HSCs. The tissue-remodeling effect of LPS may be attributable to its ability to activate non-canonical Smad pathway through PI3K/Akt and MAPK signaling cascades.
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17
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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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18
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Yu Z, Wu F, Tian J, Guo X, An R, Guo Y. Ammonium glycyrrhizin counteracts liver injury caused by lipopolysaccharide/amoxicillin-clavulanate potassium. Oncotarget 2017; 8:96837-96851. [PMID: 29228575 PMCID: PMC5722527 DOI: 10.18632/oncotarget.18291] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 05/07/2017] [Indexed: 12/31/2022] Open
Abstract
We treated isolated chicken primary hepatocytes with lipopolysaccharide/amoxicillin clavulanate potassium (LPS/AC) to model liver injury and investigate its underlying mechanisms. We also used this model to assess the cytoprotective effects of compound ammonium glycyrrhizin (CAG) in vitro. LPS/AC-induced injury decreased cell viability and increased the activity of serum aspartate transaminase and alanine transaminase. Levels of superoxide dismutase, glutathione, and glutathione peroxidase were lower than control, while levels of the oxidative product malondialdehyde and reactive oxygen species were higher. Treatment with CAG for 24 h ameliorated these changes. Caspase-3 activity assays and flow cytometry revealed increased apoptosis in the model group. However, apoptosis decreased after CAG treatment, as confirmed by Hoechst 33342 staining. We also observed changes in mitochondrial ultrastructure. Real-time PCR and western blot analyses showed that CAG treatment downregulated LPS/AC-induced RNA expression of caspase-3, caspase-9, bax, cytochrome c, and fas, and upregulated the expression of bcl-2. Mitochondrial cytochrome c was released into the cytosol and the inner mitochondrial membrane potential (ΔΨm) was decreased. Our results highlight CAG as a potential therapeutic agent to counteract LPS/AC-induced liver injury.
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Affiliation(s)
- Zugong Yu
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
| | - Feng Wu
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
| | - Jing Tian
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
| | - Xuewen Guo
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
| | - Ran An
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
| | - Yangyang Guo
- Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu Province, 210095, China
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19
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Noor MT, Manoria P. Immune Dysfunction in Cirrhosis. J Clin Transl Hepatol 2017; 5:50-58. [PMID: 28507927 PMCID: PMC5411357 DOI: 10.14218/jcth.2016.00056] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/20/2017] [Accepted: 02/08/2017] [Indexed: 02/06/2023] Open
Abstract
Cirrhosis due to any etiology disrupts the homeostatic role of liver in the body. Cirrhosis-associated immune dysfunction leads to alterations in both innate and acquired immunity, due to defects in the local immunity of liver as well as in systemic immunity. Cirrhosis-associated immune dysfunction is a dynamic phenomenon, comprised of both increased systemic inflammation and immunodeficiency, and is responsible for 30% mortality. It also plays an important role in acute as well as chronic decompensation. Immune paralysis can accompany it, which is characterized by increase in anti-inflammatory cytokines and suppression of proinflammatory cytokines. There is also presence of increased gut permeability, reduced gut motility and altered gut flora, all of which leads to increased bacterial translocation. This increased bacterial translocation and consequent endotoxemia leads to increased blood stream bacterial infections that cause systemic inflammatory response syndrome, sepsis, multiorgan failure and death. The gut microbiota of cirrhotic patients has more pathogenic microbes than that of non-cirrhotic individuals, and this disturbs the homeostasis and favors gut translocation. Prompt diagnosis and treatment of such infections are necessary for better survival. We have reviewed the various mechanisms of immune dysfunction and its consequences in cirrhosis. Recognizing the exact pathophysiology of immune dysfunction will help treating clinicians in avoiding its complications in their patients and can lead to newer therapeutic interventions and reducing the morbidity and mortality rates.
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Affiliation(s)
- Mohd Talha Noor
- Department of Gastroenterology, Sri Aurobindo Medical College and Post Graduate Institute, Indore, India
- *Correspondence to: Mohd Talha Noor, Department of Gastroenterology, Sri Aurobindo Medical College and Post Graduate Institute, Indore 453 111, India. Tel: +91-7314231751, +91-8305421496, Fax: +91-7314231012, E-mail: ,
| | - Piyush Manoria
- Department of Gastroenterology, Sri Aurobindo Medical College and Post Graduate Institute, Indore, India
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20
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Kumar S, Wang J, Thomson AW, Gandhi CR. Hepatic stellate cells increase the immunosuppressive function of natural Foxp3+ regulatory T cells via IDO-induced AhR activation. J Leukoc Biol 2016; 101:429-438. [PMID: 27581538 DOI: 10.1189/jlb.2a0516-239r] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 07/20/2016] [Accepted: 08/04/2016] [Indexed: 12/14/2022] Open
Abstract
Immunosuppressive, naturally occurring CD4+CD25+forkhead box p3+ (Foxp3+) regulatory T cells (nTregs) offer potential for the treatment of immune-mediated inflammatory disorders. However, potential instability of ex vivo-expanded nTregs following their adoptive transfer may be a significant limitation. LPS-stimulated hepatic stellate cells (HSCs) induce expansion and enhance the suppressive function and stability of allogeneic nTregs We aimed to delineate mechanisms underlying HSC-induced expansion and increased potency of nTregs HSCs and nTregs were isolated from mouse livers and spleens, respectively. Following coculture with LPS-pretreated allogeneic HSCs (LPS/HSCs), proliferation of nTregs was measured by CFSE dilution, and Foxp3 expression and acetylation were determined by immunoprecipitation (IP) and Western blotting analysis. Expression of various genes associated with immunologic tolerance was determined by quantitative RT-PCR (qRT-PCR). LPS stimulation increased the expression and activity of the immunoregulatory enzyme IDO1 in HSCs, and LPS/HSCs stimulated aryl hydrocarbon receptor (AhR) signaling in cocultured nTregs Reciprocally, Tregs increased IDO1 expression in HSCs. IDO1-/- LPS/HSCs were inferior to WT LPS/HSCs in stimulating nTreg expansion. Pharmacologic inhibition of IDO1 in HSCs by 1-methyltryptophan (1MT) inhibited LPS/HSC-induced AhR signaling in nTregs, which was responsible for their expansion, Foxp3 expression, and stabilization of Foxp3 by increasing acetylation of lysine residues. Finally, HSCs cryopreserved, following 2-3 passages, were as potent as primary-cultured HSCs in expanding nTregs In conclusion, LPS/HSCs expand allogeneic nTregs through an IDO-dependent, AhR-mediated mechanism and increase their stability through lysine-acetylation of Foxp3. nTregs expanded by cryopreserved HSCs may have potential for clinical use.
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Affiliation(s)
- Sudhir Kumar
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA.,Cincinnati VA Medical Center, Cincinnati, Ohio, USA
| | - Jiang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, USA
| | - Angus W Thomson
- Thomas E. Starzl Transplantation Institute, Departments of Surgery and Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA; and
| | - Chandrashekhar R Gandhi
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio, USA; .,Cincinnati VA Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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21
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Demetris AJ, Bellamy COC, Gandhi CR, Prost S, Nakanuma Y, Stolz DB. Functional Immune Anatomy of the Liver-As an Allograft. Am J Transplant 2016; 16:1653-80. [PMID: 26848550 DOI: 10.1111/ajt.13749] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/26/2016] [Accepted: 01/28/2016] [Indexed: 01/25/2023]
Abstract
The liver is an immunoregulatory organ in which a tolerogenic microenvironment mitigates the relative "strength" of local immune responses. Paradoxically, necro-inflammatory diseases create the need for most liver transplants. Treatment of hepatitis B virus, hepatitis C virus, and acute T cell-mediated rejection have redirected focus on long-term allograft structural integrity. Understanding of insults should enable decades of morbidity-free survival after liver replacement because of these tolerogenic properties. Studies of long-term survivors show low-grade chronic inflammatory, fibrotic, and microvascular lesions, likely related to some combination of environment insults (i.e. abnormal physiology), donor-specific antibodies, and T cell-mediated immunity. The resultant conundrum is familiar in transplantation: adequate immunosuppression produces chronic toxicities, while lightened immunosuppression leads to sensitization, immunological injury, and structural deterioration. The "balance" is more favorable for liver than other solid organ allografts. This occurs because of unique hepatic immune physiology and provides unintended benefits for allografts by modulating various afferent and efferent limbs of allogenic immune responses. This review is intended to provide a better understanding of liver immune microanatomy and physiology and thereby (a) the potential structural consequences of low-level, including allo-antibody-mediated injury; and (b) how liver allografts modulate immune reactions. Special attention is given to the microvasculature and hepatic mononuclear phagocytic system.
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Affiliation(s)
- A J Demetris
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA
| | - C O C Bellamy
- Department of Pathology, University of Edinburgh, Edinburgh, Scotland, UK
| | - C R Gandhi
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center and Department of Surgery, University of Cincinnati, Cincinnati, OH
| | - S Prost
- Department of Pathology, University of Edinburgh, Edinburgh, Scotland, UK
| | - Y Nakanuma
- Department of Diagnostic Pathology, Shizuoka Cancer Center, Shizuoka, Japan
| | - D B Stolz
- Center for Biologic Imaging, Cell Biology, University of Pittsburgh, Pittsburgh, PA
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22
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Dangi A, Huang C, Tandon A, Stolz D, Wu T, Gandhi CR. Endotoxin-stimulated Rat Hepatic Stellate Cells Induce Autophagy in Hepatocytes as a Survival Mechanism. J Cell Physiol 2016; 231:94-105. [PMID: 26031389 DOI: 10.1002/jcp.25055] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/26/2015] [Indexed: 12/15/2022]
Abstract
Bacterial lipopolysaccharide (LPS)-stimulated hepatic stellate cells (HSCs) produce many cytokines including IFNβ, TNFα, and IL6, strongly inhibit DNA synthesis, but induce apoptosis of a small number of hepatocytes. In vivo administration of LPS (up to 10 mg/mL) causes modest inflammation and weight loss in rats but not mortality. We determined whether LPS-stimulated HSCs instigate mechanisms of hepatocyte survival. Rats received 10 mg/kg LPS (i.p.) and determinations were made at 6 h. In vitro, HSCs were treated with 100 ng/mL LPS till 24 h. The medium was transferred to hepatocytes, and determinations were made at 0-12 h. Controls were HSC-conditioned medium or medium-containing LPS. LPS treatment of rats caused autophagy in hepatocytes, a physiological process for clearance of undesirable material including injured or damaged organelles. This was accompanied by activation of c-Jun NH2 terminal kinase (JNK) and apoptosis of ~4-5% of hepatocytes. In vitro, LPS-conditioned HSC medium (LPS/HSC) induced autophagy in hepatocytes but apoptosis of only ~10% of hepatocytes. While LPS/HSC stimulated activation of JNK (associated with cell death), it also activated NFkB and ERK1/2 (associated with cell survival). LPS-stimulated HSCs produced IFNβ, and LPS/HSC-induced autophagy in hepatocytes and their apoptosis were significantly inhibited by anti-IFNβ antibody. Blockade of autophagy, on the other hand, strongly augmented hepatocyte apoptosis. While LPS-stimulated HSCs cause apoptosis of a subpopulation of hepatocytes by producing IFNβ, they also induce cell survival mechanisms, which may be of critical importance in resistance to liver injury during endotoxemia.
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Affiliation(s)
- Anil Dangi
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio.,Cincinnati VA Medical Center, Cincinnati, Ohio
| | - Chao Huang
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ashish Tandon
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio
| | - Donna Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Tong Wu
- Department of Pathology and Laboratory Medicine, Tulane University School of Medicine, New Orleans, Louisiana
| | - Chandrashekhar R Gandhi
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Surgery, University of Cincinnati, and Cincinnati VA Medical Center, Cincinnati, Ohio.,Cincinnati VA Medical Center, Cincinnati, Ohio.,Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
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23
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Abstract
Alcoholic liver disease (ALD) is a complex process that includes a wide spectrum of hepatic lesions, from steatosis to cirrhosis. Cell injury, inflammation, oxidative stress, regeneration and bacterial translocation are key drivers of alcohol-induced liver injury. Alcoholic hepatitis is the most severe form of all the alcohol-induced liver lesions. Animal models of ALD mainly involve mild liver damage (that is, steatosis and moderate inflammation), whereas severe alcoholic hepatitis in humans occurs in the setting of cirrhosis and is associated with severe liver failure. For this reason, translational studies using humans and human samples are crucial for the development of new therapeutic strategies. Although multiple attempts have been made to improve patient outcome, the treatment of alcoholic hepatitis is still based on abstinence from alcohol and brief exposure to corticosteroids. However, nearly 40% of patients with the most severe forms of alcoholic hepatitis will not benefit from treatment. We suggest that future clinical trials need to focus on end points other than mortality. This Review discusses the main pathways associated with the progression of liver disease, as well as potential therapeutic strategies targeting these pathways.
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Yang XF, He Y, Li HY, Liu X, Chen H, Liu JB, Ji WJ, Wang B, Chen LN. Hepatoprotective effects of erythropoietin on D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure in mice. Mol Med Rep 2014; 10:555-9. [PMID: 24788561 DOI: 10.3892/mmr.2014.2164] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 03/24/2014] [Indexed: 01/18/2023] Open
Abstract
Fulminant hepatic failure is a severe clinical syndrome associated with a high rate of patient mortality. Recent studies have shown that in addition to its hematopoietic effect, erythropoietin (EPO) has multiple protective effects and exhibits antiapoptotic, antioxidant and anti-inflammatory activities. The present study aimed to determine the hepatoprotective effect of EPO and to elucidate the underlying mechanisms using a D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced model of acute liver injury. Experimental groups of mice were administered with various doses of EPO (1,000, 3,000 or 10,000 U/kg, intraperitoneal) once per day for 3 days, prior to injection with D-GalN (700 mg/kg)/LPS (10 µg/kg). Mice were sacrificed 8 h after treatment with D‑GalN/LPS. Liver function and histopathology, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH‑Px) activities and EPO receptor (EPOR) and phosphatidylinositol 3-kinase (PI3K) mRNA expression were evaluated. D-GalN/LPS administration markedly induced liver injury, as evidenced by elevated levels of serum aminotransferases, as well as histopathological changes. Compared with the D-GalN/LPS group, pretreatment with EPO significantly decreased the levels of aspartate aminotransferase, alanine aminotransferase and MDA, and increased the activities of SOD and GSH-Px. Furthermore, the protective effects of EPO were paralleled by an upregulation in the mRNA expression of EPOR and PI3K. These data suggest that EPO can ameliorate D-GalN/LPS-induced acute liver injury by reducing oxidative stress and upregulating the mRNA expression of EPOR and PI3K.
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Affiliation(s)
- Xue-Fei Yang
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yi He
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Hai-Yuan Li
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Xin Liu
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Huan Chen
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Jian-Bang Liu
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Wen-Jun Ji
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Bing Wang
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Li-Na Chen
- Department of Pharmacology, College of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
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25
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Zhang Y, Ghazwani M, Li J, Sun M, Stolz DB, He F, Fan J, Xie W, Li S. MiR-29b inhibits collagen maturation in hepatic stellate cells through down-regulating the expression of HSP47 and lysyl oxidase. Biochem Biophys Res Commun 2014; 446:940-4. [PMID: 24650661 DOI: 10.1016/j.bbrc.2014.03.037] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 03/10/2014] [Indexed: 02/06/2023]
Abstract
Altered expression of miR-29b is implicated in the pathogenesis and progression of liver fibrosis. We and others previously demonstrated that miR-29b down-regulates the expression of several extracellular-matrix (ECM) genes including Col 1A1, Col 3A1 and Elastin via directly targeting their 3'-UTRs. However, whether or not miR-29b plays a role in the post-translational regulation of ECM biosynthesis has not been reported. Heat shock protein 47 (HSP47) and lysyl oxidase (LOX) are known to be essential for ECM maturation. In this study we have demonstrated that expression of HSP47 and LOX was significantly up-regulated in culture-activated primary rat hepatic stellate cells (HSCs), TGF-β stimulated LX-2 cells and liver tissue of CCl4-treated mice, which was accompanied by a decrease of miR-29b level. In addition, over-expression of miR-29b in LX-2 cells resulted in significant inhibition on HSP47 and LOX expression. Mechanistically, miR-29b inhibited the expression of a reporter gene that contains the respective full-length 3'-UTR from HSP47 and LOX gene, and this inhibitory effect was abolished by the deletion of a putative miR-29b targeting sequence from the 3'-UTRs. Transfection of LX-2 cells with miR-29b led to abnormal collagen structure as shown by electron-microscopy, presumably through down-regulation of the expression of molecules involved in ECM maturation including HSP47 and LOX. These results demonstrated that miR-29b is involved in regulating the post-translational processing of ECM and fibril formation.
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Affiliation(s)
- Yifei Zhang
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Mohammed Ghazwani
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Jiang Li
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Ming Sun
- Department of Cell Biology and Physiology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Donna B Stolz
- Department of Cell Biology and Physiology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Fengtian He
- Department of Biochemistry and Molecular Biology, College of Basic Medical Sciences, Third Military Medical University, Chongqing 400038, China
| | - Jie Fan
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Wen Xie
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States
| | - Song Li
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, United States.
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26
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Stewart RK, Dangi A, Huang C, Murase N, Kimura S, Stolz DB, Wilson GC, Lentsch AB, Gandhi CR. A novel mouse model of depletion of stellate cells clarifies their role in ischemia/reperfusion- and endotoxin-induced acute liver injury. J Hepatol 2014; 60:298-305. [PMID: 24060854 PMCID: PMC4195246 DOI: 10.1016/j.jhep.2013.09.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Revised: 08/05/2013] [Accepted: 09/03/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hepatic stellate cells (HSCs) that express glial fibrillary acidic protein (GFAP) are located between the sinusoidal endothelial cells and hepatocytes. HSCs are activated during liver injury and cause hepatic fibrosis by producing excessive extracellular matrix. HSCs also produce many growth factors, chemokines and cytokines, and thus may play an important role in acute liver injury. However, this function has not been clarified due to unavailability of a model, in which HSCs are depleted from the normal liver. METHODS We treated mice expressing HSV-thymidine kinase under the GFAP promoter (GFAP-Tg) with 3 consecutive (3 days apart) CCl4 (0.16 μl/g; ip) injections to stimulate HSCs to enter the cell cycle and proliferate. This was followed by 10-day ganciclovir (40 μg/g/day; ip) treatment, which is expected to eliminate actively proliferating HSCs. Mice were then subjected to hepatic ischemia/reperfusion (I/R) or endotoxin treatment. RESULTS CCl4/ganciclovir treatment caused depletion of the majority of HSCs (about 64-72%), while the liver recovered from the initial CCl4-induced injury (confirmed by histology, serum ALT and neutrophil infiltration). The magnitude of hepatic injury due to I/R or endotoxemia (determined by histopathology and serum ALT) was lower in HSC-depleted mice. Their hepatic expression of TNF-α, neutrophil chemoattractant CXCL1 and endothelin-A receptor also was significantly lower than the control mice. CONCLUSIONS HSCs play an important role both in I/R- and endotoxin-induced acute hepatocyte injury, with TNF-α and endothelin-1 as important mediators of these effects.
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Affiliation(s)
- Rachel K. Stewart
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Anil Dangi
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213,Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Chao Huang
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Noriko Murase
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Shoko Kimura
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213
| | - Donna B. Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Gregory C. Wilson
- Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Alex B. Lentsch
- Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA
| | - Chandrashekhar R. Gandhi
- Thomas E. Starzl Transplantation Institute and Departments of Surgery, University of Pittsburgh, Pittsburgh, PA 15213,Department of Surgery University of Cincinnati and Cincinnati VA Medical Center, Cincinnati, OH, USA and Cincinnati Veterans Administration, Cincinnati, OH, USA,Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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27
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The transcriptomic response of rat hepatic stellate cells to endotoxin: implications for hepatic inflammation and immune regulation. PLoS One 2013; 8:e82159. [PMID: 24349206 PMCID: PMC3857241 DOI: 10.1371/journal.pone.0082159] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/26/2013] [Indexed: 12/13/2022] Open
Abstract
With their location in the perisinusoidal space of Disse, hepatic stellate cells (HSCs) communicate with all of the liver cell types both by physical association (cell body as well as cytosolic processes penetrating into sinusoids through the endothelial fenestrations) and by producing several cytokines and chemokines. Bacterial lipopolysaccharide (LPS), circulating levels of which are elevated in liver diseases and transplantation, stimulates HSCs to produce increased amounts of cytokines and chemokines. Although recent research provides strong evidence for the role of HSCs in hepatic inflammation and immune regulation, the number of HSC-elaborated inflammatory and immune regulatory molecules may be much greater then known at the present time. Here we report time-dependent changes in the gene expression profile of inflammatory and immune-regulatory molecules in LPS-stimulated rat HSCs, and their validation by biochemical analyses. LPS strongly up-regulated LPS-response elements (TLR2 and TLR7) but did not affect TLR4 and down-regulated TLR9. LPS also up-regulated genes in the MAPK, NFκB, STAT, SOCS, IRAK and interferon signaling pathways, numerous CC and CXC chemokines and IL17F. Interestingly, LPS modulated genes related to TGFβ and HSC activation in a manner that would limit their activation and fibrogenic activity. The data indicate that LPS-stimulated HSCs become a major cell type in regulating hepatic inflammatory and immunological responses by altering expression of numerous relevant genes, and thus play a prominent role in hepatic pathophysiology including liver diseases and transplantation.
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28
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Ou TT, Kuo CY, Chyau CC, Lee HJ, Peng JS, Wang CJ. Improvement of lipopolysaccharide-induced hepatic injuries and inflammation with mulberry extracts. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2013; 93:1880-1886. [PMID: 23238799 DOI: 10.1002/jsfa.5984] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 10/11/2012] [Accepted: 11/09/2012] [Indexed: 06/01/2023]
Abstract
BACKGROUND Mulberry water extracts (MWEs), which contain polyphenols including anthocyanins, have been used in traditional Chinese edible food. The hepatoprotective effects and molecular mechanisms of MWEs on acute liver failure induced by lipopolysaccharides (LPS) were investigated in vivo. RESULTS Rats were administered different doses of MWEs (0.5 and 1 g kg(-1)) 1 h before injection of LPS (5 mg kg(-1)) and then sacrificed 10 h after treatment with LPS. Liver function, inflammatory factors, oxidative stress index and hepatic histopathological alteration were examined in the rats with and without MWE treatment. Pretreatment with MWEs prevented LPS-induced liver damage by preventing associated increases of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALKP), triglycerol (TG), cholesterol and low-density lipoprotein/high-density lipoprotein ratio. MWEs also suppressed oxidative stress to prevent the formation of hepatic malondialdehyde (MDA). Furthermore, the molecular mechanism involved in LPS-induced liver injury was associated with reducing the expression of COX-2, NF-κB and iNOS in liver tissues. CONCLUSION The results support the investigation of MWEs as a therapeutic candidate for liver injuries and indicate that MWEs exhibit hepatoprotective activities via NF-κB signaling.
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Affiliation(s)
- Ting-Tsz Ou
- Institute of Biochemistry and Biotechnology, Chung Shan Medical University, and Department of Clinical laboratory, Tai-An Hospital, Taichung, Taiwan, ROC
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29
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Vodovotz Y, Prelich J, Lagoa C, Barclay D, Zamora R, Murase N, Gandhi CR. Augmenter of liver regeneration (ALR) is a novel biomarker of hepatocellular stress/inflammation: in vitro, in vivo and in silico studies. Mol Med 2013; 18:1421-9. [PMID: 23073658 PMCID: PMC3563711 DOI: 10.2119/molmed.2012.00183] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 10/09/2012] [Indexed: 12/15/2022] Open
Abstract
The liver is a central organ involved in inflammatory processes, including the elaboration of acute-phase proteins. Augmenter of liver regeneration (ALR) protein, expressed and secreted by hepatocytes, promotes liver regeneration and maintains viability of hepatocytes. ALR also stimulates secretion of inflammatory cytokines (tumor necrosis factor [TNF]-α and interleukin [IL]-6) and nitric oxide from Kupffer cells. We hypothesized that ALR may be involved in modulating inflammation induced by various stimuli. We found that hepatic ALR levels are elevated at 24 h, before or about the same time as an increase in the mRNA expression of TNF-α and IL-6, after portacaval shunt surgery in rats. Serum ALR also increased, but significantly only on d 4 when pathological changes in the liver become apparent. In rats, serum ALR was elevated after intraperitoneal administration of lipopolysaccharide alone and in a model of gram-negative sepsis. Serum ALR increased before alanine aminotransferase (ALT) in endotoxemia and in the same general time frame as TNF-α and IL-6 in the bacterial sepsis model. Furthermore, mathematical prediction of tissue damage correlated strongly with alterations in serum ALR in a mouse model of hemorrhagic shock. In vitro, monomethyl sulfonate, TNF-α, actinomycin D and lipopolysaccharide all caused increased release of ALR from rat hepatocytes, which preceded the loss of cell viability and/or inhibition of DNA synthesis. ALR may thus serve as a potential diagnostic marker of hepatocellular stress and/or acute inflammatory conditions.
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Affiliation(s)
- Yoram Vodovotz
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, United States of America
| | - John Prelich
- VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania, United States of America
| | - Claudio Lagoa
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Derek Barclay
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Ruben Zamora
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Center for Inflammation and Regenerative Modeling, McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Noriko Murase
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Chandrashekhar R Gandhi
- Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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30
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Dangi A, Sumpter TL, Kimura S, Stolz DB, Murase N, Raimondi G, Vodovotz Y, Huang C, Thomson AW, Gandhi CR. Selective expansion of allogeneic regulatory T cells by hepatic stellate cells: role of endotoxin and implications for allograft tolerance. THE JOURNAL OF IMMUNOLOGY 2012; 188:3667-77. [PMID: 22427640 DOI: 10.4049/jimmunol.1102460] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepatic stellate cells (HSCs) may play an important role in hepatic immune regulation by producing numerous cytokines/chemokines and expressing Ag-presenting and T cell coregulatory molecules. Due to disruption of the endothelial barrier during cold-ischemic storage and reperfusion of liver grafts, HSCs can interact directly with cells of the immune system. Endotoxin (LPS), levels of which increase in liver diseases and transplantation, stimulates the synthesis of many mediators by HSCs. We hypothesized that LPS-stimulated HSCs might promote hepatic tolerogenicity by influencing naturally occurring immunosuppressive CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs). Following their portal venous infusion, allogeneic CD4(+) T cells, including Tregs, were found closely associated with HSCs, and this association increased in LPS-treated livers. In vitro, both unstimulated and LPS-stimulated HSCs upregulated Fas (CD95) expression on conventional CD4(+) T cells and induced their apoptosis in a Fas/Fas ligand-dependent manner. By contrast, HSCs induced Treg proliferation, which required cell-cell contact and was MHC class II-dependent. This effect was augmented when HSCs were pretreated with LPS. LPS increased the expression of MHC class II, CD80, and CD86 and stimulated the production of IL-1α, IL-1β, IL-6, IL-10 and TNF-α by HSCs. Interestingly, production of IL-1α, IL-1β, IL-6, and TNF-α was strongly inhibited, but that of IL-10 enhanced in LPS-pretreated HSC/Treg cocultures. Adoptively transferred allogeneic HSCs migrated to the secondary lymphoid tissues and induced Treg expansion in lymph nodes. These data implicate endotoxin-stimulated HSCs as important immune regulators in liver transplantation by inducing selective expansion of tolerance-promoting Tregs and reducing inflammation and alloimmunity.
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Affiliation(s)
- Anil Dangi
- Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
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31
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Abstract
In the steady state, hepatic antigen (Ag)-presenting cells (APC) generally dampen systemic inflammatory responses to gut-derived Ags. Our studies focus on the role of specific liver APC populations, both non-parenchymal cells (dendritic cells [DC], Kupffer cells, and hepatic stellate cells [HSC]) and parenchymal cells, in the molecular regulation of tissue damage (ischemia and reperfusion [I/R] injury) and immunity following liver transplantation. We focus on factors that either promote or overwhelm the natural tendency of the liver to suppress inflammatory/immune responses. We are also examining molecular mechanisms that regulate liver DC maturation and function and that determine their role in the control of allogeneic T-cell function and the fate of the transplanted liver. Our studies are also aimed at elucidating mechanisms by which HSC regulate DC and T-cell function. These investigations may provide new targets for therapeutic intervention in liver inflammation.
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32
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Zhao L, Gandhi CR, Gao ZH. Involvement of cytosolic phospholipase A2 alpha signalling pathway in spontaneous and transforming growth factor-beta-induced activation of rat hepatic stellate cells. Liver Int 2011; 31:1565-73. [PMID: 22093332 DOI: 10.1111/j.1478-3231.2011.02632.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Accepted: 08/01/2011] [Indexed: 12/23/2022]
Abstract
BACKGROUND Hepatic stellate cells (HSCs) are extracellular matrix-producing cells that play a pivotal role in liver fibrogenesis. During liver injury and when cells are placed in vitro, HSCs undergo phenotypic transition from quiescent retinoid-storing cells to activated retinoid-deficient myofibroblast-like cells. Although several mediators including reactive oxygen species, platelet derived growth factor, transforming growth factor-beta (TGF-β) and tumour necrosis factor-alpha (TNF-α) were implicated in HSC activation, the cellular signalling pathways that regulate this process remain incompletely defined. AIMS The objectives of this study were to evaluate the role of cytosolic phospholipase A(2) alpha (cPLA(2)α) and peroxisome proliferator-activated receptor-beta/delta (PPAR-β/δ) in HSC activation. METHODS Rat HSCs were isolated, purified, cultured and stimulated with TGF-β1 in the presence or absence of the selective cPLA(2)α inhibitor, arachidonyltrifluoromethyl ketone (AACOCF(3)). The activation status of HSC was evaluated by immunofluorescent staining of alpha-smooth muscle actin (α-SMA) and by measuring the expression of cPLA(2)α, cyclooxygenase 2 (COX-2) and PPAR-β/δ using western blot analysis. RESULTS Rapid and significant increase in cPLA(2)α expression was observed during activation of HSCs. These events preceded the elevation of PPAR-β/δ and the expression of α-SMA. Elevated expression of cPLA(2)α, but not COX-2, was also observed during TGF-β-induced HSC activation. The TGF-β-induced α-SMA expression was blocked by AACOCF(3). Furthermore, transfection of a cPLA(2)α expression vector enhanced the transcription activity of PPAR-β/δ and the expression of α-SMA in HSCs. CONCLUSION cPLA(2)α-mediated induction of PPAR-β/δ is a novel intracellular signalling pathway in spontaneous and TGF-β induced activation of HSCs and could be a potential therapeutic target for the treatment of liver fibrosis.
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Affiliation(s)
- Liena Zhao
- Department of Pathology and Laboratory Medicine, University of Calgary and Calgary Laboratory Services, Calgary, AB, Canada
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Li J, Zhang Y, Kuruba R, Gao X, Gandhi CR, Xie W, Li S. Roles of microRNA-29a in the antifibrotic effect of farnesoid X receptor in hepatic stellate cells. Mol Pharmacol 2011; 80:191-200. [PMID: 21511916 DOI: 10.1124/mol.110.068247] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Liver fibrosis is a chronic disorder that is characterized by an alteration of the balance between fibrogenesis and fibrinolysis, which results in accumulation of excessive amounts of extracellular matrix (ECM) and distortion of the normal liver architecture. The activation and transformation of quiescent hepatic stellate cells (HSCs) into myofibroblast-like cells constitute a major mechanism for the increased production of ECM in the liver. The nuclear receptor farnesoid X receptor (FXR) shows potent antifibrotic activity in HSCs and protects animals in rodent models of liver fibrosis. However, the detailed mechanism remains incompletely understood. In this study, we report that treatment with 3-[2-[2-chloro-4-[[3-(2,6-dichlorophenyl)-5-(1-methylethyl)-4-isoxazolyl]methoxy]phenyl]ethenyl]benzoic acid (GW4064), a synthetic FXR ligand, led to up-regulation of microRNA-29a (miR-29a) in HSCs isolated from wild-type mice, rats, and humans but not from FXR(-/-) mice. miR-29a seems to play an inhibitory role in the regulation of ECM production because of the following: 1) transfection of HSCs with miR-29a mimic resulted in drastic down-regulation of the mRNA expression of several genes that encode ECM proteins; and 2) miR-29a significantly inhibited the expression of a reporter expression plasmid that contains the 3'-untranslated region of the corresponding ECM genes. Our results suggest that miR-29a is a FXR target gene because miR-29a promoter activity was significantly increased by pharmacologic or genetic activation of FXR. Functional analysis of human miR-29a promoter identified an imperfect inverted repeat spaced by one nucleotide DNA motif, inverted repeat-1 (5'-AGGTCAcAGACCT-3'), as a likely FXR-responsive element that is involved in miR-29a regulation. Our study uncovers a new mechanism by which FXR negatively regulates the expression of ECM in HSCs.
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Affiliation(s)
- Jiang Li
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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35
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Baicalein inhibits nuclear factor-κB and apoptosis via c-FLIP and MAPK in D-GalN/LPS induced acute liver failure in murine models. Chem Biol Interact 2010; 188:526-34. [PMID: 20850421 DOI: 10.1016/j.cbi.2010.09.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 09/07/2010] [Accepted: 09/07/2010] [Indexed: 12/16/2022]
Abstract
The hepatoprotective effects and molecular mechanisms of baicalein on acute liver failure induced by d-galactosamine (d-GalN)/lipopolysaccharides (LPS) were investigated in vivo. Mice were administered with different doses of baicalein (50, 100 or 150mg/kg, p.o.) 1h before injection of d-GalN (700mg/kg)/LPS (10μg/kg) and then sacrificed 6h after treatment with d-GalN/LPS. Pretreatment with baicalein prevented d-GalN/LPS-induced liver damage by preventing associated increases of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and by reducing serum tumor necrosis factor α (TNF-α), nitric oxide (NO) or inducible nitric oxide synthase (iNOS) expressions. The molecular mechanisms involved in baicalein-induced inhibition of d-GalN/LPS-caused apoptosis were associated with the protection of mitochondria, increasing the Bcl-2/Bax ratio, blocking the release of cytochrome c, and suppressing the phosphorylation of IκBα, ERK and JNK. Moreover, baicalein activated c-FLIP(L), XIAP and cIAP2 proteins, potentially blocking the recruitment of NF-κB signaling molecules. The results support the investigation of baicalein as a therapeutic candidate for acute liver apoptosis or injury and indicate that baicalein might inhibit liver apoptosis by mediating one or more of these pathways.
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36
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Liu LM, Zhang JX, Wang XP, Guo HX, Deng H, Luo J. Pim-3 protects against hepatic failure in D-galactosamine (D-GalN)-sensitized rats. Eur J Clin Invest 2010; 40:127-38. [PMID: 20039932 DOI: 10.1111/j.1365-2362.2009.02235.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Fulminant hepatic failure (FHF) has a high mortality resulted from massive hepatic apoptosis and haemorrhage necrosis; it is required to develop a valid therapy directed towards hepatocyte protection and regeneration. Pim-3, a hepatic growth stimulator, belongs to the serine/threonine kinase Pim-family that has been implicated in gp130-mediated induction of cell proliferation, protection from apoptosis downstream of Signal transducer and activator of transcription 3 (STAT3) and vascular endothelial growth factor-A-dependent vasculogenesis and angiogenesis, thus is suggested to possibly play a role in the tissue repair of FHF. MATERIALS AND METHODS Male Wistar rats received simultaneous intraperitoneal injections of lipopolysaccharide (LPS) (100 microg kg(-1)) and D-galactosamine (D-GalN) (600 mg kg(-1)). One day prior to LPS/D-GalN administration, naked plasmid or Ringer's solution was injected via tail vein by hydrodynamics-based procedure. RESULTS Exogenous Pim-3 gene protected against LPS/D-GalN-induced lethality with survival rate of more than 80% and improved the hepatic pathomorphism. The fractions of hepatic apoptotic-positive cells and the levels of caspase-3 activity were markedly lower in Pim-3-pretreated rats. Furthermore, exogenous Pim-3 significantly inhibited expression of tumour necrosis factor-alpha and interleukin-1beta in the liver, declined p53 and inducible nitric oxide synthase mRNAs levels, but elevated levels of Bcl-2 protein, an anti-apoptosis member of Bcl-2 family, in the liver. Exogenous Pim-3, however, showed little effect on expression of Bax, a pro-apoptosis member of Bcl-2 family. CONCLUSIONS Pim-3 gene could protect rats from FHF by inhibiting liver apoptosis and improving inflammatory response of liver tissues, which could be associated with inhibiting expression of inflammatory mediators and promoting expression of anti-apoptosis protein Bcl-2.
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Affiliation(s)
- L-M Liu
- Jiangxi Provincial Key Laboratory of Molecular Medicine, Nanchang, China
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Wu YL, Lian LH, Jiang YZ, Nan JX. Hepatoprotective effects of salidroside on fulminant hepatic failure induced by d-galactosamine and lipopolysaccharide in mice. J Pharm Pharmacol 2010. [DOI: 10.1211/jpp.61.10.0015] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Abstract
Objectives
The aim was to investigate the protective effect of salidroside isolated from Rhodiola sachalinensis A. Bor. (Crassulaceae) on d-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.
Methods
Hepatotoxicity was induced by an intraperitoneal injection of d-galactosamine (700 mg/kg) and lipopolysaccharide (10 μg/kg); salidroside (20, 50 and 100 mg/kg) was administered intraperitoneally 1 h before induction of hepatoxicity. Liver injury was assessed biochemically and histologically.
Key findings
Salidroside attenuated the induced acute increase in serum aspartate aminotransferase and alanine aminotransferase activities, and levels of tumour necrosis factor-alpha levels and serum nitric oxide. It restored depleted hepatic glutathione, superoxide dismutase, catalase and glutathione peroxidase activities, decreased malondialdehyde levels and considerably reduced histopathological changes. Histopathological, immunohistochemical and Western blot analyses also demonstrated that salidroside could reduce the appearance of necrotic regions and expression of caspase-3 and hypoxia-inducible factor-1α in liver tissue.
Conclusions
Salidroside protected liver tissue from the oxidative stress elicited by d-galactosamine and lipopolysaccharide. The hepatoprotective mechanism of salidroside appear to be related to antioxidant activity and inhibition of hypoxia-inducible factor-1α.
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Affiliation(s)
- Yan-Ling Wu
- Key Laboratory for Natural Resource of Changbai Mountain & Functional Molecules, Ministry of Education, College of Pharmacy, Yanbian University, Jilin Province, China
| | - Li-Hua Lian
- Key Laboratory for Natural Resource of Changbai Mountain & Functional Molecules, Ministry of Education, College of Pharmacy, Yanbian University, Jilin Province, China
| | - Ying-Zi Jiang
- Key Laboratory for Natural Resource of Changbai Mountain & Functional Molecules, Ministry of Education, College of Pharmacy, Yanbian University, Jilin Province, China
| | - Ji-Xing Nan
- Key Laboratory for Natural Resource of Changbai Mountain & Functional Molecules, Ministry of Education, College of Pharmacy, Yanbian University, Jilin Province, China
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Jameel NM, Thirunavukkarasu C, Wu T, Watkins SC, Friedman SL, Gandhi CR. p38-MAPK- and caspase-3-mediated superoxide-induced apoptosis of rat hepatic stellate cells: reversal by retinoic acid. J Cell Physiol 2008; 218:157-66. [PMID: 18792915 DOI: 10.1002/jcp.21581] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Reactive oxygen species (ROS) activate retinoid-containing quiescent hepatic stellate cells (qHSCs) to retinoid-deficient fibrogenic myofibroblast-like cells (aHSCs). However, ROS also cause apoptosis of aHSCs, and apoptotic aHSCs are observed in inflammatory fibrotic liver. Here, we investigated mechanisms of the effects of oxidative stress on the survival of qHSCs and aHSCs. HSCs from normal rat liver were used after overnight culture (qHSCs), or in 3-5 passages (aHSCs). For in vivo induction of oxidative stress, tert-butylhydroperoxide was injected into control and CCl4-induced cirrhotic rats. Spontaneous caspase-3 activation and apoptosis, observed in cultured qHSCs, decreased with time and were unaffected by superoxide. In contrast, superoxide caused caspase-3 and p38-MAPK activation, reduction in Bcl-xL expression, and apoptosis in aHSCs. Inhibition of caspase-3 and p38-MAPK did not affect the viability of qHSCs in the absence or presence of superoxide, but inhibited superoxide-induced death of aHSCs. Glutathione (GSH) level and activities of superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) were lower in aHSCs than qHSCs. Superoxide increased GSH content, and activities of SOD, catalase and GPx in qHSCs but not in aHSCs. Incubation of 13-cis-retinoic acid (RA)-treated aHSCs with superoxide increased their GSH content significantly, and prevented superoxide-induced p38-MAPK and caspase-3 activation while dramatically reducing the extent of apoptosis. Finally, oxidative stress induced in vivo caused apoptosis of aHSCs in cirrhotic but not of qHSCs in control rats. These results suggest that the absence of retinoids render aHSCs susceptible to superoxide-induced apoptosis via caspase-3 and p38-MAPK activation.
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Affiliation(s)
- Noor Mohamed Jameel
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
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A TLR4/MD2 fusion protein inhibits LPS-induced pro-inflammatory signaling in hepatic stellate cells. Biochem Biophys Res Commun 2008; 375:210-4. [PMID: 18694726 DOI: 10.1016/j.bbrc.2008.07.150] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 07/30/2008] [Indexed: 01/22/2023]
Abstract
Activated hepatic stellate cells (HSCs) play a key role in hepatic fibrogenesis. In injured liver they are the main extracellular matrix protein producing cell type and further perpetuate hepatic injury by secretion of pro-inflammatory mediators. Since LPS-mediated signaling through toll-like receptor 4 (TLR4) has been identified as key fibrogenic signal in HSCs we aimed to test TLR4 as potential target of therapy via ligand-binding soluble receptors. Incubation of human HSCs with a fusion protein between the extracellular domain of TLR4 and MD2 which binds LPS inhibited LPS-induced NFkappaB and JNK activation. TLR4/MD2 abolished LPS-induced secretion of IL-6, IL-8, MCP1, and RANTES in HSCs. In addition, TLR4/MD2 fused to human IgG-Fc neutralized LPS activity. Since TLR4 mutant mice are resistant to liver fibrosis, the TLR4/MD2 soluble receptor might represent a new therapeutic molecule for liver fibrogenesis in vivo.
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Purohit V, Bode JC, Bode C, Brenner DA, Choudhry MA, Hamilton F, Kang YJ, Keshavarzian A, Rao R, Sartor RB, Swanson C, Turner JR. Alcohol, intestinal bacterial growth, intestinal permeability to endotoxin, and medical consequences: summary of a symposium. Alcohol 2008; 42:349-61. [PMID: 18504085 DOI: 10.1016/j.alcohol.2008.03.131] [Citation(s) in RCA: 232] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 03/11/2008] [Accepted: 03/27/2008] [Indexed: 12/13/2022]
Abstract
This report is a summary of the symposium on Alcohol, Intestinal Bacterial Growth, Intestinal Permeability to Endotoxin, and Medical Consequences, organized by National Institute on Alcohol Abuse and Alcoholism, Office of Dietary Supplements, and National Institute of Diabetes and Digestive and Kidney Diseases of National Institutes of Health in Rockville, Maryland, October 11, 2006. Alcohol exposure can promote the growth of Gram-negative bacteria in the intestine, which may result in accumulation of endotoxin. In addition, alcohol metabolism by Gram-negative bacteria and intestinal epithelial cells can result in accumulation of acetaldehyde, which in turn can increase intestinal permeability to endotoxin by increasing tyrosine phosphorylation of tight junction and adherens junction proteins. Alcohol-induced generation of nitric oxide may also contribute to increased permeability to endotoxin by reacting with tubulin, which may cause damage to microtubule cytoskeleton and subsequent disruption of intestinal barrier function. Increased intestinal permeability can lead to increased transfer of endotoxin from the intestine to the liver and general circulation where endotoxin may trigger inflammatory changes in the liver and other organs. Alcohol may also increase intestinal permeability to peptidoglycan, which can initiate inflammatory response in liver and other organs. In addition, acute alcohol exposure may potentiate the effect of burn injury on intestinal bacterial growth and permeability. Decreasing the number of Gram-negative bacteria in the intestine can result in decreased production of endotoxin as well as acetaldehyde which is expected to decrease intestinal permeability to endotoxin. In addition, intestinal permeability may be preserved by administering epidermal growth factor, l-glutamine, oats supplementation, or zinc, thereby preventing the transfer of endotoxin to the general circulation. Thus reducing the number of intestinal Gram-negative bacteria and preserving intestinal permeability to endotoxin may attenuate alcoholic liver and other organ injuries.
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Affiliation(s)
- Vishnudutt Purohit
- Division of Metabolism and Health Effects, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5635 Fishers Lane, Room 2035, MSC 9304, Bethesda, MD 20892-9304, USA.
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Liu LM, Zhang JX, Luo J, Guo HX, Deng H, Chen JY, Sun SL. A role of cell apoptosis in lipopolysaccharide (LPS)-induced nonlethal liver injury in D-galactosamine (D-GalN)-sensitized rats. Dig Dis Sci 2008; 53:1316-24. [PMID: 17934810 DOI: 10.1007/s10620-007-9994-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Accepted: 08/20/2007] [Indexed: 02/06/2023]
Abstract
Lipopolysaccharide (LPS) is implicated in the pathology of acute liver injury and can induce lethal liver failure when simultaneously administered with D-galactosamine (D-GalN). At the present time, nonlethal liver failure, the liver injury of clinical implication, is incompletely understood following challenge by low-dose LPS/D-GalN. We report here our investigation of the effects of liver injury following a nonlethal dose LPS/D-GalN and the role of apoptosis in this disorder. Blood biochemistry indexes, including those of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBIL), had risen by 6 h post-LPS/D-GalN injection, reached a peak at 24 h and sustained high levels at 48 h. An abnormal liver appearance was found at 24 and 48 h post-injection. Histopathological changes of hepatic injuries accompanied by hepatocellular death, inflammatory infiltration and hemorrhage began to appear at 6 h and were markedly aggravated at 24 and 48 h. Cell apoptosis was significantly induced by the nonlethal dose LPS/D-GalN challenge, and the apoptotic indexes (AIs) in 24 h- and 48 h-treated rats were approximately 70%, as estimated by the terminal transferase dUTP nick end labeling (TUNEL) assay. The mRNA levels of the inflammatory cytokine IL-1beta rose markedly at 6 h and maintained high levels at 24 and 48 h; however, TNF-alpha levels were normal in the liver tissues of 6-, 24- and 48-h-treated rats. mRNA expression of the damage gene nitric oxide synthase (NOS) was also induced early by the LPS/D-GalN challenge, reaching a peak at 6 h, then gradually decreasing in a stepwise manner; conversely, high expression levels of the apoptosis-inducing gene p53 mRNA were not found in the early post-injection period (6 h) but emerged in the crest-time of liver apoptosis (24 h) and were maintained at this level until the late stage (48 h). We also observed that in 24 h-treated rats, caspase-3, -8, -9 and -12 were markedly activated by LPS/D-GalN challenge. These results suggest that a challenge with low-dose LPS in conjunction with D-GalN can induce nonlethal but marked liver failure, the main morphological feature of which is hepatic apoptosis, which may be associated with a high expression of inducible (i)NOS (early post-injection period) and p53 genes (in the mid and late stages) and at least three apoptosis pathways participate in the pathogenesis.
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Affiliation(s)
- Liang-Ming Liu
- Department of Gastroenterology, Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
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Abstract
The hepatic stellate cell has surprised and engaged physiologists, pathologists, and hepatologists for over 130 years, yet clear evidence of its role in hepatic injury and fibrosis only emerged following the refinement of methods for its isolation and characterization. The paradigm in liver injury of activation of quiescent vitamin A-rich stellate cells into proliferative, contractile, and fibrogenic myofibroblasts has launched an era of astonishing progress in understanding the mechanistic basis of hepatic fibrosis progression and regression. But this simple paradigm has now yielded to a remarkably broad appreciation of the cell's functions not only in liver injury, but also in hepatic development, regeneration, xenobiotic responses, intermediary metabolism, and immunoregulation. Among the most exciting prospects is that stellate cells are essential for hepatic progenitor cell amplification and differentiation. Equally intriguing is the remarkable plasticity of stellate cells, not only in their variable intermediate filament phenotype, but also in their functions. Stellate cells can be viewed as the nexus in a complex sinusoidal milieu that requires tightly regulated autocrine and paracrine cross-talk, rapid responses to evolving extracellular matrix content, and exquisite responsiveness to the metabolic needs imposed by liver growth and repair. Moreover, roles vital to systemic homeostasis include their storage and mobilization of retinoids, their emerging capacity for antigen presentation and induction of tolerance, as well as their emerging relationship to bone marrow-derived cells. As interest in this cell type intensifies, more surprises and mysteries are sure to unfold that will ultimately benefit our understanding of liver physiology and the diagnosis and treatment of liver disease.
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Affiliation(s)
- Scott L Friedman
- Division of Liver Diseases, Mount Sinai School of Medicine, New York, New York 10029-6574, USA.
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Vonlaufen A, Xu Z, Daniel B, Kumar RK, Pirola R, Wilson J, Apte MV. Bacterial endotoxin: a trigger factor for alcoholic pancreatitis? Evidence from a novel, physiologically relevant animal model. Gastroenterology 2007; 133:1293-303. [PMID: 17919500 DOI: 10.1053/j.gastro.2007.06.062] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2006] [Accepted: 06/14/2007] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS This study examined the possible role of endotoxinemia (from increased gut permeability) as an additional trigger factor for overt pancreatic disease and as a promoter of chronic pancreatic injury in alcoholics by using a rat model of chronic alcohol feeding and in vitro experiments with cultured pancreatic stellate cells (PSCs), the key mediators of pancreatic fibrosis. METHODS In the in vivo model, Sprague-Dawley rats fed isocaloric Lieber-DeCarli liquid diets +/- alcohol for 10 weeks were challenged with a single dose or 3 repeated doses of the endotoxin lipopolysaccharide (LPS) and the pancreas was examined. In the in vitro studies, rat PSCs were assessed for activation on exposure to LPS +/- ethanol. The expression of LPS receptors TLR4 and CD14 also was assessed in rat and human PSCs. RESULTS In the in vivo model, single or repeated LPS challenge resulted in significantly greater pancreatic injury in alcohol-fed rats compared with rats fed the control diet without alcohol. Notably, repeated LPS injections caused pancreatic fibrosis in alcohol-fed rats, but not in rats fed the control diet. In the in vitro studies, PSCs were activated by LPS. Alcohol + LPS exerted a synergistic effect on PSC activation. Importantly, both rat and human PSCs expressed TLR4 and CD14. CONCLUSIONS This study describes, for the first time, a clinically relevant animal model of alcohol-related pancreatic injury and provides strong in vivo and in vitro evidence that suggests that LPS is a trigger factor in the initiation and progression of alcoholic pancreatitis.
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Affiliation(s)
- Alain Vonlaufen
- Pancreatic Research Group, South Western Sydney Clinical School, Sydney, Australia
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Zhang P, Fan XG, Zhang BX, Zhong BY. Optimization of mouse model of fulminant hepatic failure by factorial experiment. Shijie Huaren Xiaohua Zazhi 2007; 15:1141-1145. [DOI: 10.11569/wcjd.v15.i10.1141] [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
AIM: To establish a stable and effective mouse model of fulminant hepatic failure (FHF) induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS).
METHODS: Two factors, attacking dosages of D-GalN and LP, influencing the success of modeling were chosen by factorial experiment. Three dosages of two factors were injected into the peritoneal cavity of mice and the death rate within 24 h was calculated. Liver function and liver histopathological changes were also detected.
RESULTS: Two administration projects were chosen: 600 mg/kg D-GalN combined with 0.5 mg/kg LPS, or 800 mg/kg D-GalN combined with 0.04 mg/kg LPS. The death rates were affected by D-GalN and LPS in dose-dependent manner (F = 36.878, P = 0.000; F = 32.386, P = 0.000). There are interaction between D-GalN and LPS (F = 5.226, P = 0.005), and the combinatory administration of D-GalN and LPS increased the death rates of mice obviously.
CONCLUSION: The standard model of mouse FHF can be established successfully using factorial experiment.
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Zeng G, Awan F, Otruba W, Muller P, Apte U, Tan X, Gandhi C, Demetris AJ, Monga SPS. Wnt'er in liver: expression of Wnt and frizzled genes in mouse. Hepatology 2007; 45:195-204. [PMID: 17187422 DOI: 10.1002/hep.21473] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
UNLABELLED The Wnt signaling pathway is essential for a wide array of developmental and physiological processes. Wnts are extracellular ligands that bind to frizzled (Fz) receptors at the membrane, canonically inducing beta-catenin nuclear translocation and activation. Although beta-catenin has been shown to be critical in liver biology, the expression of the 19 Wnt and 10 Fz genes in liver remains undetermined. We report comprehensive analysis of Wnt and Fz expression in whole liver as well as individual cell types: freshly isolated and plated hepatocytes, biliary epithelial cells, normal and activated stellate and Kupffer cells, and sinusoidal endothelial cells (SECs). Oligonucleotides for the 19 Wnt, 10 frizzled receptors genes, and secreted Frizzled-related protein-1 (sFRP or Fzb) were synthesized based on the available sequences. A total of 11 Wnts and 8 Fz genes and Fzb were expressed in normal liver. Although only 6 Wnt and 5 Fz genes were expressed in freshly isolated hepatocytes, 8 Wnt genes, 7 Fz genes, and Fzb were expressed in plated hepatocytes. Although 12 Wnt and 7 Fz genes were expressed in biliary tree, additional Fz9 and Fzb were only expressed in cultured biliary epithelial cells. The same 14 Wnt and 7 Fz genes were expressed in both activated and normal stellate and Kupffer cells; only Fzb was expressed in their activated state. Also, 11 Wnt, seven Fz, and Fzb genes were expressed in SECs. CONCLUSION These data indicate that most Wnt and frizzled genes are expressed in the liver and might be playing important roles in liver pathobiology via canonical and noncanonical pathways.
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Affiliation(s)
- Gang Zeng
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15261, USA
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Thirunavukkarasu C, Watkins SC, Gandhi CR. Mechanisms of endotoxin-induced NO, IL-6, and TNF-alpha production in activated rat hepatic stellate cells: role of p38 MAPK. Hepatology 2006; 44:389-98. [PMID: 16871588 DOI: 10.1002/hep.21254] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Compelling experimental evidence indicates that the interactions between endotoxin and hepatic stellate cells (HSCs) can play a significant role in the pathogenesis of liver disease. Endotoxin-induced release of a multifunctional mediator NO (via inducible NO synthase) and the proinflammatory cytokines tumor necrosis factor alpha (TNF-alpha) and interleukin (IL)-6 by HSCs could be an important mechanism of pathological changes in the liver. However, the signaling mechanisms of these effects are poorly understood. In this study, we found that endotoxin causes activation of mitogen-activated protein kinases (MAPKs) (extracellular signal-regulated protein kinase [ERK] 1 and 2, p38, and c-Jun NH2-terminal kinase [JNK]) and nuclear factor kappaB (NF-kappaB) and production of H(2)O(2) in culture-activated HSCs. However, only p38 and NF-kappaB were found to be responsible for the synthesis of NO, IL-6, and TNF-alpha. Exogenous H(2)O(2) caused modest stimulation of TNF-alpha synthesis, did not affect the synthesis of NO or IL-6, and did not activate NF-kappaB or MAPKs. Inhibition of p38 and NF-kappaB activation by SB203580 and pyrrolidine dithiocarbamate, respectively, blocked endotoxin-induced H(2)O(2), NO, TNF-alpha, and IL-6 synthesis. Inhibition of ERK1/2 and JNK phosphorylation did not alter these effects of endotoxin. Whereas SB203580 inhibited endotoxin-induced NF-kappaB activation, pyrrolidine dithiocarbamate did not affect p38 phosphorylation in endotoxin-stimulated cells. In conclusion, endotoxin-induced synthesis of NO, TNF-alpha, and IL-6 in HSCs is mediated by p38 and NF-kappaB, with involvement of H(2)O(2) in TNF-alpha production.
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Affiliation(s)
- Chinnasamy Thirunavukkarasu
- Department of Surgery, Thomas E. Starzl Transplantation Institute, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Abstract
Pattern recognition receptors (PRRs) function as sensors of microbial danger signals enabling the vertebrate host to initiate an immune response. PRRs are present not only in immune cells but also in liver parenchymal cells and the complexity of the cell populations provide unique aspects to pathogen recognition and tissue damage in the liver. This review discusses the role of different PRRs in pathogen recognition in the liver, and focuses on the role of PRRs in hepatic inflammation, cholestasis, ischemia, repair and fibrosis. PRRs as novel therapeutic targets are evaluated.
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Affiliation(s)
- Gyongyi Szabo
- Liver Center, Division of Gastroenterology, Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA.
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Affiliation(s)
- Robert F Schwabe
- Department of Medicine, Columbia University, College of Physicians and Surgeons, New York, New York, USA.
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