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Grayck MR, McCarthy WC, Solar M, Balasubramaniyan N, Zheng L, Orlicky DJ, Wright CJ. Implications of neonatal absence of innate immune mediated NFκB/AP1 signaling in the murine liver. Pediatr Res 2024; 95:1791-1802. [PMID: 38396130 DOI: 10.1038/s41390-024-03071-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 01/03/2024] [Accepted: 01/20/2024] [Indexed: 02/25/2024]
Abstract
BACKGROUND The developmental immaturity of the innate immune system helps explains the increased risk of infection in the neonatal period. Importantly, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for the prevention of hepatocyte apoptosis in adult animals, yet whether developmental immaturity of these pathways increases the risk of hepatic injury in the neonatal period is unknown. METHODS Using a murine model of endotoxemia (LPS 5 mg/kg IP x 1) in neonatal (P3) and adult mice, we evaluated histologic evidence of hepatic injury and apoptosis, presence of p65/NFκB and c-Jun/AP1 activation and associated transcriptional regulation of apoptotic genes. RESULTS We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis. This is associated with absent hepatic p65/NFκB signaling and impaired expression of anti-apoptotic target genes. Hepatic c-Jun/AP1 activity was attenuated in endotoxemic P3 mice, with resulting upregulation of pro-apoptotic factors. CONCLUSIONS These results demonstrate that developmental absence of innate immune p65/NFκB and c-Jun/AP1 signaling, and target gene expression is associated with apoptotic injury in neonatal mice. More work is needed to determine if this contributes to long-term hepatic dysfunction, and whether immunomodulatory approaches can prevent this injury. IMPACT Various aspects of developmental immaturity of the innate immune system may help explain the increased risk of infection in the neonatal period. In adult models of inflammation and infection, innate immune signaling pathways such as p65/NFκB and c-Jun/AP1 are responsible for a protective, pro-inflammatory transcriptome and regulation of apoptosis. We demonstrate that in contrast to adults, endotoxemic neonatal (P3) mice exhibit a significant increase in hepatic apoptosis associated with absent hepatic p65/NFκB signaling and c-Jun/AP1 activity. We believe that these results may explain in part hepatic dysfunction with neonatal sepsis, and that there may be unrecognized developmental and long-term hepatic implications of early life exposure to systemic inflammatory stress.
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Affiliation(s)
- Maya R Grayck
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - William C McCarthy
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Mack Solar
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Natarajan Balasubramaniyan
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Lijun Zheng
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - David J Orlicky
- Dept of Pathology, University of Colorado Anschutz School of Medicine, Aurora, CO, USA
| | - Clyde J Wright
- Section of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA.
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Zhou Z, Qi J, Lim CW, Kim JW, Kim B. Dual TBK1/IKKε inhibitor amlexanox mitigates palmitic acid-induced hepatotoxicity and lipoapoptosis in vitro. Toxicology 2020; 444:152579. [PMID: 32905826 DOI: 10.1016/j.tox.2020.152579] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/24/2020] [Accepted: 09/01/2020] [Indexed: 02/08/2023]
Abstract
The common causes of Non-alcoholic fatty liver disease (NAFLD) are obesity, dyslipidemia, and insulin resistance. Metabolic disorders and lipotoxic hepatocyte damage are hallmarks of NAFLD. Even though amlexanox, a dual inhibitor of TRAF associated nuclear factor κB (NF-κB) activator-binding kinase 1 (TBK1) and IκB kinase epsilon (IKKε), has been reported to effectively improve obesity-related metabolic dysfunctions in mice models, its molecular mechanism has not been fully investigated. This study was designed to investigate the effects of amlexanox on in vitro nonalcoholic steatohepatitis (NASH) model induced by treatment of palmitic acid (PA, 0.4 mM), using a trans-well co-culture system of hepatocytes and Kupffer cells (KCs). Stimulation with PA significantly increased the phosphorylation levels of TBK1 and IKKε in both hepatocytes and KCs, suggesting a potential role of TBK1/IKKε in PA-induced NASH progression. Treatment of amlexanox (50 μM) showed significantly reduced phosphorylation of TBK1 and IKKε and hepatotoxicity as confirmed by decreased levels of lactate dehydrogenase released from hepatocytes. Furthermore, PA-induced inflammation and lipotoxic cell death in hepatocytes were significantly reversed by amlexanox treatment. Intriguingly, amlexanox inhibited the activation of KCs and induced polarization of KCs towards M2 phenotype. Mechanistically, amlexanox treatment decreased the phosphorylation of interferon regulator factor 3 (IRF3) and NF-κB in PA-treated hepatocytes. However, decreased phosphorylation of NF-κB, not IRF3, was found in PA-treated KCs upon amlexanox treatment. Taken together, our findings show that treatment of amlexanox attenuated the severity of PA-induced hepatotoxicity in vitro and lipoapoptosis by the inhibition of TBK1/IKKε-NF-κB and/or IRF3 pathway in hepatocytes and KCs.
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Affiliation(s)
- Zixiong Zhou
- Biosafety Research Institute and Laboratory of Pathology (BK21 Plus Program), College of Veterinary Medicine, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Jing Qi
- Biosafety Research Institute and Laboratory of Pathology (BK21 Plus Program), College of Veterinary Medicine, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Chae Woong Lim
- Biosafety Research Institute and Laboratory of Pathology (BK21 Plus Program), College of Veterinary Medicine, Jeonbuk National University, Iksan, 54596, Republic of Korea
| | - Jong-Won Kim
- Biosafety Research Institute and Laboratory of Pathology (BK21 Plus Program), College of Veterinary Medicine, Jeonbuk National University, Iksan, 54596, Republic of Korea.
| | - Bumseok Kim
- Biosafety Research Institute and Laboratory of Pathology (BK21 Plus Program), College of Veterinary Medicine, Jeonbuk National University, Iksan, 54596, Republic of Korea.
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Giustarini G, Huppelschoten S, Barra M, Oppelt A, Wagenaar L, Weaver RJ, Bol-Schoenmakers M, Smit JJ, van de Water B, Klingmüller U, Pieters RHH. The hepatotoxic fluoroquinolone trovafloxacin disturbs TNF- and LPS-induced p65 nuclear translocation in vivo and in vitro. Toxicol Appl Pharmacol 2020; 391:114915. [PMID: 32035082 DOI: 10.1016/j.taap.2020.114915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 01/10/2020] [Accepted: 02/05/2020] [Indexed: 01/26/2023]
Abstract
Idiosyncratic drug-induced liver injury (IDILI) is a severe disease that cannot be detected during drug development. It has been shown that hepatotoxicity of some compounds associated with IDILI becomes apparent when these are combined in vivo and in vitro with LPS or TNF. Among these compounds trovafloxacin (TVX) induced apoptosis in the liver and increased pro-inflammatory cytokines in mice exposed to LPS/TNF. The hepatocyte survival and the cytokine release after TNF/LPS stimulation relies on a pulsatile activation of NF-κB. We set out to evaluate the dynamic activation of NF-κB in response to TVX + TNF or LPS models, both in mouse and human cells. Remarkably, TVX prolonged the first translocation of NF-κB induced by TNF both in vivo and in vitro. The prolonged p65 translocation caused by TVX was associated with an increased phosphorylation of IKK and MAPKs and accumulation of inhibitors of NF-κB such as IκBα and A20 in HepG2. Coherently, TVX suppressed further TNF-induced NF-κB translocations in HepG2 leading to decreased transcription of ICAM-1 and inhibitors of apoptosis. TVX prolonged LPS-induced NF-κB translocation in RAW264.7 macrophages increasing the secretion of TNF. In summary, this study presents new, relevant insights into the mechanism of TVX-induced liver injury underlining the resemblance between mouse and human models. In this study we convincingly show that regularly used toxicity models provide a coherent view of relevant pathways for IDILI. We propose that assessment of the kinetics of activation of NF-κB and MAPKs is an appropriate tool for the identification of hepatotoxic compounds during drug development.
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Affiliation(s)
- Giulio Giustarini
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
| | - Suzanna Huppelschoten
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Marco Barra
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands; University of Pisa, Department of Pharmacy, Italy
| | - Angela Oppelt
- Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Laura Wagenaar
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Richard J Weaver
- Biopharmacy, Institut de Recherches Internationales Servier (I.R.I.S.), Suresnes 92284, France
| | - Marianne Bol-Schoenmakers
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Joost J Smit
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Bob van de Water
- Division of Drug Discovery and Safety, Leiden Academic Centre for Drug Research, Leiden University, Leiden, the Netherlands
| | - Ursula Klingmüller
- Division Systems Biology of Signal Transduction, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Raymond H H Pieters
- Immunotoxicology, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands.
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RNA-seq profiles of chicken type II pneumocyte in response to Escherichia coli infection. PLoS One 2019; 14:e0217438. [PMID: 31166969 PMCID: PMC6550405 DOI: 10.1371/journal.pone.0217438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 05/10/2019] [Indexed: 12/31/2022] Open
Abstract
Avian pathogenic Escherichia coli (APEC) causes great economic loss to the poultry industry worldwide. Chicken type II pneumocytes (CP II cells) secrete surfactants and modulate lung immunity to decrease the infection of the invading pathogen. Nevertheless, the pathogenesis of CP II cells to APEC infection remains poorly understood. Therefore, we conducted global gene expression profiling of CP II cells after APEC-O78 infection to explore the host-pathogen interaction. The differentially expressed genes of CP II cells to APEC infection were characterized by RNA-seq with EB-seq algorithm. In consequence, the mRNA of 18996 genes was identified, and CP II cells responded to APEC infection with marked changes in the expression of 1390 genes. Among them, there are 803 down-regulated mRNAs and 587 up-regulated mRNAs. The KEGG prediction and Gene Ontology terms analysis revealed that the major enriched pathways were related to NF-κB signaling pathway, apoptosis pathway, tight junction, and cytokine-cytokine receptor interaction and other pathways. We adopted qRT-PCR to verify the validity of the selected gene expression. The fold induction of qPCR was similar to the RNA-seq results. These results provide a better understanding of the pathogenesis of APEC, especially apoptosis pathway involved in APEC infection.
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5
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Wu J, Zhao Y, Park YK, Lee JY, Gao L, Zhao J, Wang L. Loss of PDK4 switches the hepatic NF-κB/TNF pathway from pro-survival to pro-apoptosis. Hepatology 2018; 68:1111-1124. [PMID: 29603325 PMCID: PMC6165716 DOI: 10.1002/hep.29902] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/10/2018] [Accepted: 03/23/2018] [Indexed: 12/11/2022]
Abstract
It has been established that nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) members promote survival by upregulating antiapoptotic genes and that genetic and pharmacological inhibition of NF-κB is required for tumor necrosis factor (TNF)-induced hepatocyte apoptosis. In this study, we demonstrate that this pro-survival pathway is switched to pro-apoptosis under pyruvate dehydrogenase kinase 4 (PDK4)-deficient conditions. PDK4-deficiency triggered hepatic apoptosis concomitantly with increased numbers of aberrant mitochondria, reactive oxygen species (ROS) production, sustained c-Jun N-terminal Kinase (JNK) activation, and reduction of glutathione (GSH). Interestingly, PDK4 retained p65 in cytoplasm via a direct protein-protein interaction. Disruption of PDK4-p65 association promoted p65 nuclear translocation. This, in turn, facilitated p65 binding to the TNF promoter to activate TNF-TNFR1 apoptotic pathway. Pdk4-/- livers were sensitized to Jo2 and D-(+)-Galactosamine /Lipopolysaccharide (GalN/LPS)-mediated apoptotic injury which was prevented by the inhibition of p65 or TNFR1. The pro-survival activity of TNF was shifted, which was switched to a pro-apoptotic activity in Pdk4-/- hepatocytes as a result of impaired activation of pro-survival NF-κB targets. Conclusion: PDK4 is indispensable to dictate the fate of TNF/NF-κB-mediated hepatocyte apoptosis. (Hepatology 2018).
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Affiliation(s)
- Jianguo Wu
- Department of Physiology and Neurobiology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269,Corresponding author: Jianguo Wu (), 75 North Eagleville Rd., U3156, Storrs, CT 06269. Tel: 860-486-0857; Fax: 860-486-3303
| | - Yulan Zhao
- Department of Physiology and Neurobiology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Young-Ki Park
- Department of Nutritional Sciences, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Ji-Young Lee
- Department of Nutritional Sciences, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269
| | - Ling Gao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, 250021, China,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, 250021, China,Institute of Endocrinology and metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China
| | - Jiajun Zhao
- Department of Endocrinology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, 250021, China,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, Shandong, 250021, China,Institute of Endocrinology and metabolism, Shandong Academy of Clinical Medicine, Jinan, Shandong, 250021, China
| | - Li Wang
- Department of Physiology and Neurobiology, Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269,Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516,Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, CT 06520
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Gilgenkrantz H, Collin de l'Hortet A. Understanding Liver Regeneration: From Mechanisms to Regenerative Medicine. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:1316-1327. [PMID: 29673755 DOI: 10.1016/j.ajpath.2018.03.008] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 03/15/2018] [Accepted: 03/23/2018] [Indexed: 02/06/2023]
Abstract
Liver regeneration is a complex and unique process. When two-thirds of a mouse liver is removed, the remaining liver recovers its initial weight in approximately 10 days. The understanding of the mechanisms responsible for liver regeneration may help patients needing large liver resections or transplantation and may be applied to the field of regenerative medicine. All differentiated hepatocytes are capable of self-renewal, but different subpopulations of hepatocytes seem to have distinct proliferative abilities. In the setting of chronic liver diseases, a ductular reaction ensues in which liver progenitor cells (LPCs) proliferate in the periportal region. Although these LPCs have the capacity to differentiate into hepatocytes and biliary cells in vitro, their ability to participate in liver regeneration is far from clear. Their expansion has even been associated with increased fibrosis and poorer prognosis in chronic liver diseases. Controversies also remain on their origin: lineage studies in experimental mouse models of chronic injury have recently suggested that these LPCs originate from hepatocyte dedifferentiation, whereas in other situations, they seem to come from cholangiocytes. This review summarizes data published in the past 5 years in the liver regeneration field, discusses the mechanisms leading to regeneration disruption in chronic liver disorders, and addresses the potential use of novel approaches for regenerative medicine.
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Affiliation(s)
- Hélène Gilgenkrantz
- INSERM U1149, Center for Research on Inflammation, Université Paris Diderot, Sorbonne Paris Cité, Paris, France.
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Abstract
Hepatic ischemia/reperfusion (I/R) injury is a major complication of liver surgery, including liver resection, liver transplantation, and trauma surgery. Much has been learned about the inflammatory injury response induced by I/R, including the cascade of proinflammatory mediators and recruitment of activated leukocytes. In this review, we discuss the complex network of events that culminate in liver injury after I/R, including cellular, protein, and molecular mechanisms. In addition, we address the known endogenous regulatory mediators that function to maintain homeostasis and resolve injury. Finally, we cover more recent insights into how the liver repairs and regenerates after I/R injury, a setting in which physical mass remains unchanged, but functional liver mass is greatly reduced. In this regard, we focus on recent work highlighting a novel role of CXC chemokines as important regulators of hepatocyte proliferation and liver regeneration after I/R injury.
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Affiliation(s)
- Takanori Konishi
- Department of Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Alex B. Lentsch
- Department of Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
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8
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Lalazar G, Ilyas G, Malik SA, Liu K, Zhao E, Amir M, Lin Y, Tanaka KE, Czaja MJ. Autophagy confers resistance to lipopolysaccharide-induced mouse hepatocyte injury. Am J Physiol Gastrointest Liver Physiol 2016; 311:G377-86. [PMID: 27469366 PMCID: PMC5076014 DOI: 10.1152/ajpgi.00124.2016] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 07/12/2016] [Indexed: 01/31/2023]
Abstract
During sepsis, bacterial products, particularly LPS, trigger injury in organs such as the liver. This common condition remains largely untreatable, in part due to a lack of understanding of how high concentrations of LPS cause cellular injury. In the liver, the lysosomal degradative pathway of autophagy performs essential hepatoprotective functions and is induced by LPS. We, therefore, examined whether hepatocyte autophagy protects against liver injury from septic levels of LPS. Mice with an inducible hepatocyte-specific knockout of the critical autophagy gene Atg7 were examined for their sensitivity to high-dose LPS. Increased liver injury occurred in knockout mice, as determined by significantly increased serum alanine aminotransferase levels, histological evidence of liver injury, terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling, and effector caspase-3 and -7 activation. Hepatic inflammation and proinflammatory cytokine induction were unaffected by the decrease in hepatocyte autophagy. Although knockout mice had normal NF-κB signaling, hepatic levels of Akt1 and Akt2 phosphorylation in response to LPS were decreased. Cultured hepatocytes from knockout mice displayed a generalized defect in Akt signaling in response to multiple stimuli, including LPS, TNF, and IL-1β. Akt activation mediates hepatocyte resistance to TNF cytotoxicity, and anti-TNF antibodies significantly decreased LPS-induced liver injury in knockout mice, indicating that the loss of autophagy sensitized to TNF-dependent liver damage. Hepatocyte autophagy, therefore, protects against LPS-induced liver injury. Conditions such as aging and steatosis that impair hepatic autophagy may predispose to poor outcomes from sepsis through this mechanism.
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Affiliation(s)
- Gadi Lalazar
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Ghulam Ilyas
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Shoaib Ahmad Malik
- 2Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; ,3Department of Biochemistry, Sargodha Medical College, University of Sargodha, Sargodha, Pakistan; and
| | - Kun Liu
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Enpeng Zhao
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Mohammad Amir
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Yu Lin
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York;
| | - Kathryn E. Tanaka
- 4Department of Pathology, Albert Einstein College of Medicine, Bronx, New York
| | - Mark J. Czaja
- 1Department of Medicine and the Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York; ,2Division of Digestive Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia;
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Liu K, Zhao E, Ilyas G, Lalazar G, Lin Y, Haseeb M, Tanaka KE, Czaja MJ. Impaired macrophage autophagy increases the immune response in obese mice by promoting proinflammatory macrophage polarization. Autophagy 2016; 11:271-84. [PMID: 25650776 DOI: 10.1080/15548627.2015.1009787] [Citation(s) in RCA: 329] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Recent evidence that excessive lipid accumulation can decrease cellular levels of autophagy and that autophagy regulates immune responsiveness suggested that impaired macrophage autophagy may promote the increased innate immune activation that underlies obesity. Primary bone marrow-derived macrophages (BMDM) and peritoneal macrophages from high-fat diet (HFD)-fed mice had decreased levels of autophagic flux indicating a generalized impairment of macrophage autophagy in obese mice. To assess the effects of decreased macrophage autophagy on inflammation, mice with a Lyz2-Cre-mediated knockout of Atg5 in macrophages were fed a HFD and treated with low-dose lipopolysaccharide (LPS). Knockout mice developed systemic and hepatic inflammation with HFD feeding and LPS. This effect was liver specific as knockout mice did not have increased adipose tissue inflammation. The mechanism by which the loss of autophagy promoted inflammation was through the regulation of macrophage polarization. BMDM and Kupffer cells from knockout mice exhibited abnormalities in polarization with both increased proinflammatory M1 and decreased anti-inflammatory M2 polarization as determined by measures of genes and proteins. The heightened hepatic inflammatory response in HFD-fed, LPS-treated knockout mice led to liver injury without affecting steatosis. These findings demonstrate that autophagy has a critical regulatory function in macrophage polarization that downregulates inflammation. Defects in macrophage autophagy may underlie inflammatory disease states such as the decrease in macrophage autophagy with obesity that leads to hepatic inflammation and the progression to liver injury.
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Key Words
- ARG1, arginase 1
- BMDM, bone marrow-derived macrophages
- CCL, chemokine (C-C motif) ligand
- CD, chow diet
- CHIL3/CHI3L3, chitinase-like 3
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescent protein
- GPT, glutamic pyruvic transaminase, soluble
- HFD, high-fat diet
- IFNG, interferon gamma
- IL, interleukin
- Kupffer cells
- LPS, lipopolysaccharide
- MAP1LC3/LC3B, microtubule-associated protein 1 light chain 3 β
- MAPK, mitogen-activated protein kinase
- MGL2, macrophage galactose N-acetyl-galactosamine specific lectin 2
- NOS2, nitric oxide synthase 2, inducible
- PBS, phosphate-buffered saline
- PTGS2, prostaglandin-endoperoxide synthase 2
- RETNLA, resistin like α;
- STAT, signal transducer and activator of transcription
- TNF, tumor necrosis factor
- TUNEL, terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling
- WAT, white adipose tissue
- autophagy
- innate immunity
- lipopolysaccharide
- macrophage
- obesity
- polarization
- qRT-PCR, quantitative real-time PCR
- steatohepatitis
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Affiliation(s)
- Kun Liu
- a Department of Medicine and Marion Bessin Liver Research Center; Albert Einstein College of Medicine ; Bronx , NY USA
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Kang YJ, Bang BR, Otsuka M, Otsu K. Tissue-Specific Regulation of p38α-Mediated Inflammation in Con A-Induced Acute Liver Damage. THE JOURNAL OF IMMUNOLOGY 2015; 194:4759-66. [PMID: 25888643 DOI: 10.4049/jimmunol.1402954] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 03/16/2015] [Indexed: 01/19/2023]
Abstract
Because p38α plays a critical role in inflammation, it has been an attractive target for the development of anti-inflammation therapeutics. However, p38α inhibitors showed side effects, including severe liver toxicity, that often prevailed over the benefits in clinical studies, and the mechanism of toxicity is not clear. In this study, we demonstrate that p38α regulates the inflammatory responses in acute liver inflammation in a tissue-specific manner, and liver toxicity by p38α inhibitors may be a result of the inhibition of protective activity of p38α in the liver. Genetic ablation of p38α in T and NKT cells protected mice from liver injury in Con A-induced liver inflammation, whereas liver-specific deletion of p38α aggravated liver pathology. We found that p38α deficiency in the liver increased the expression of chemokines to recruit more inflammatory cells, indicating that p38α in the liver plays a protective anti-inflammatory role during acute liver inflammation. Therefore, our results suggest that p38α regulates the inflammatory responses in a tissue-specific manner, and that the tissue-specific p38α targeting strategies can be used for the development of an effective anti-inflammation treatment with an improved side-effect profile.
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Affiliation(s)
- Young Jun Kang
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037;
| | - Bo-Ram Bang
- Department of Immunology and Microbial Science, The Scripps Research Institute, La Jolla, CA 92037
| | - Motoyuki Otsuka
- Department of Gastroenterology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655, Japan
| | - Kinya Otsu
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan; and Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom
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Verstrepen L, Carpentier I, Beyaert R. The biology of A20-binding inhibitors of NF-kappaB activation (ABINs). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 809:13-31. [PMID: 25302363 DOI: 10.1007/978-1-4939-0398-6_2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The family of A20-Binding Inhibitors of NF-kappaB (ABINs) consists of three proteins, ABIN-1, ABIN-2 and ABIN-3, which were originally identified as A20-binding proteins and inhibitors of cytokines and Lipopolysaccharide (LPS) induced NF-kappaB activation. ABIN family members have limited sequence homology in a number of short regions that mediate A20-binding, ubiquitin-binding, and NF-kappaB inhibition. The functional role of A20 binding to ABINs remains unclear, although an adaptor function has been suggested. ABIN-1 and ABIN-3 expression is upregulated when cells are triggered by NF-kappaB-activating stimuli, suggesting a role for these ABINs in a negative feedback regulation of NF-kappaB signaling. Additional ABIN functions have been reported such as inhibition of TNF-induced hepatocyte apoptosis, regulation of HIV-1 replication for ABIN-1, and Tumor Progression Locus 2 (TPL-2)-mediated Extracellular signal-Regulated Kinase (ERK) activation for ABIN-2. In mice, ABIN-1 overexpression reduces allergic airway inflammation and TNF-mediated liver injury, ABIN-2 overexpression delays liver regeneration, and ABIN-3 overexpression partially protects against LPS-induced acute liver failure. Analysis of mice deficient in ABIN-1 or ABIN-2 demonstrates the important immune regulatory function of ABINs. Future studies should clarify the functional implication of the A20-ABIN interaction in supporting ABINs' mechanisms of action.
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12
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Zhao E, Amir M, Lin Y, Czaja MJ. Stathmin mediates hepatocyte resistance to death from oxidative stress by down regulating JNK. PLoS One 2014; 9:e109750. [PMID: 25285524 PMCID: PMC4186850 DOI: 10.1371/journal.pone.0109750] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/10/2014] [Indexed: 12/11/2022] Open
Abstract
Stathmin 1 performs a critical function in cell proliferation by regulating microtubule polymerization. This proliferative function is thought to explain the frequent overexpression of stathmin in human cancer and its correlation with a bad prognosis. Whether stathmin also functions in cell death pathways is unclear. Stathmin regulates microtubules in part by binding free tubulin, a process inhibited by stathmin phosphorylation from kinases including c-Jun N-terminal kinase (JNK). The involvement of JNK activation both in stathmin phosphorylation, and in hepatocellular resistance to oxidative stress, led to an examination of the role of stathmin/JNK crosstalk in oxidant-induced hepatocyte death. Oxidative stress from menadione-generated superoxide induced JNK-dependent stathmin phosphorylation at Ser-16, Ser-25 and Ser-38 in hepatocytes. A stathmin knockdown sensitized hepatocytes to both apoptotic and necrotic cell death from menadione without altering levels of oxidant generation. The absence of stathmin during oxidative stress led to JNK overactivation that was the mechanism of cell death as a concomitant knockdown of JNK1 or JNK2 blocked death. Hepatocyte death from JNK overactivation was mediated by the effects of JNK on mitochondria. Mitochondrial outer membrane permeabilization occurred in stathmin knockdown cells at low concentrations of menadione that triggered apoptosis, whereas mitochondrial β-oxidation and ATP homeostasis were compromised at higher, necrotic menadione concentrations. Stathmin therefore mediates hepatocyte resistance to death from oxidative stress by down regulating JNK and maintaining mitochondrial integrity. These findings demonstrate a new mechanism by which stathmin promotes cell survival and potentially tumor growth.
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Affiliation(s)
- Enpeng Zhao
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Muhammad Amir
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Yu Lin
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Mark J. Czaja
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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13
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Gonzaga NA, Callera GE, Yogi A, Mecawi AS, Antunes-Rodrigues J, Queiroz RH, Touyz RM, Tirapelli CR. Acute ethanol intake induces mitogen-activated protein kinase activation, platelet-derived growth factor receptor phosphorylation, and oxidative stress in resistance arteries. J Physiol Biochem 2014; 70:509-23. [PMID: 24733165 DOI: 10.1007/s13105-014-0331-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 03/10/2014] [Indexed: 12/16/2022]
Abstract
In the present study, we investigated the role of angiotensin type I (AT1) receptor in reactive oxygen species (ROS) generation and mitogen-activated protein kinases (MAPK) activation induced by acute ethanol intake in resistance arteries. We also evaluated the effect of ethanol on platelet-derived growth factor receptors (PDGF-R) phosphorylation and the role of this receptor on ROS generation by ethanol. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. Acute ethanol intake did not alter angiotensin I or angiotensin II levels in the rat mesenteric arterial bed (MAB). Ethanol induced vascular oxidative stress, and this response was not prevented by losartan (10 mg/kg; p.o. gavage), a selective AT1 receptor antagonist. MAB from ethanol-treated rats displayed increased SAPK/JNK and PDGF-R phosphorylation, responses that were not prevented by losartan. The phosphorylation levels of protein kinase B (Akt) and eNOS were not affected by acute ethanol intake. MAB nitrate levels and the reactivity of this tissue to acetylcholine, phenylephrine, and sodium nitroprusside were not affected by ethanol intake. Ethanol did not alter plasma antioxidant capacity, the levels of reduced glutathione, or the activities of superoxide dismutase and catalase in the rat MAB. Short-term effects of ethanol (50 mmol/l) were evaluated in vascular smooth muscle cells (VSMC) isolated from rat MAB. Ethanol increased ROS generation, and this response was not affected by AG1296, a PDGF-R inhibitor, or losartan. Finally, ethanol did not alter MAPK or PDGF-R phosphorylation in cultured VSMC. Our study provides novel evidence that acute ethanol intake induces ROS generation, PDGF-R phosphorylation, and MAPK activation through AT(1)-independent mechanisms in resistance arteries in vivo. MAPK and PDGF-R play a role in vascular signaling and cardiovascular diseases and may contribute to the vascular pathobiology of ethanol.
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Affiliation(s)
- Natália A Gonzaga
- Departamento de Enfermagem Psiquiátrica e Ciências Humanas, Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
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14
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Watson WH, Burke TJ, Doll MA, McClain CJ. S-adenosylhomocysteine inhibits NF-κB-mediated gene expression in hepatocytes and confers sensitivity to TNF cytotoxicity. Alcohol Clin Exp Res 2013; 38:889-96. [PMID: 24224954 DOI: 10.1111/acer.12315] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 09/30/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND Chronic alcohol exposure results in liver injury that is driven in part by inflammatory cytokines such as tumor necrosis factor-α (TNF). Hepatocytes are normally resistant to the cytotoxic effects of TNF, but they become sensitized to TNF by chronic alcohol exposure. Recently, we reported that the decrease in the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) that occurs with alcoholic liver injury renders hepatocytes sensitive to TNF cytotoxicity. The purpose of this study was to determine whether inhibition of the transcription factor nuclear factor-kappaB (NF-κB) contributed to TNF-induced cell death in hepatocytes with high levels of SAH. METHODS Primary human hepatocytes or HepG2 cells were pre-incubated with a combination of adenosine plus homocysteine to increase SAH levels. Following exposure to TNF, viability was determined by the MTT assay, and activation of the NF-κB pathway was assessed by measuring degradation of cytosolic IκB-α, phosphorylation and translocation of NF-κB to the nucleus, and expression of NF-κB-dependent genes. TNF-induced apoptotic signaling pathways were assessed by monitoring levels of the anti-apoptotic protein, A20, and cleavage products of the caspase-8 substrate, RIP1. RESULTS NF-κB-mediated gene expression was inhibited in cells with high SAH, despite the fact that TNF-induced degradation of the cytoplasmic inhibitor IκB-α and accumulation of NF-κB in the nucleus persisted for much longer. In contrast to control cells, the NF-κB that accumulated in the nucleus of cells with high SAH levels was not phosphorylated at serine 536, a modification associated with activation of the transactivation potential of this transcription factor. The inhibition of transactivation by NF-κB resulted in lower mRNA and protein levels of the anti-apoptotic protein A20 and increased cleavage of RIP1. CONCLUSIONS High SAH levels inhibited NF-κB-mediated gene expression and sensitized primary hepatocytes and HepG2 cells to the cytotoxic effects of TNF. It is likely that crosstalk with other transcription factors is perturbed under these conditions, resulting in still other changes in gene expression.
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Affiliation(s)
- Walter H Watson
- Division of Gastroenterology, Hepatology and Nutrition , Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; University of Louisville Alcohol Research Center , Louisville, Kentucky; Department of Pharmacology and Toxicology , University of Louisville School of Medicine, Louisville, Kentucky
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15
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Mach J, Huizer-Pajkos A, Cogger VC, McKenzie C, Le Couteur DG, Jones BE, de Cabo R, Hilmer SN. The effect of aging on acetaminophen pharmacokinetics, toxicity and Nrf2 in Fischer 344 rats. J Gerontol A Biol Sci Med Sci 2013; 69:387-97. [PMID: 23863315 DOI: 10.1093/gerona/glt095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We investigated the effect of aging on hepatic pharmacokinetics and the degree of hepatotoxicity following a toxic dose of acetaminophen. Young and old male Fischer 344 rats were treated with 800 mg/kg acetaminophen (young n = 8, old n = 5) or saline (young n = 9, old n = 9). Serum measurements showed old rats treated with acetaminophen had significantly lower serum alanine aminotransferase and higher acetaminophen and acetaminophen glucuronide levels and creatinine, compared with acetaminophen treated young rats (p < .05). Immunoblotting and activity assays showed old saline-treated rats had twofold lower cytochrome P450 2E1 activity and threefold higher NAD(P)H quinone oxireductase 1 protein expression and activity than young saline-treated rats (p < .05), although Nrf2, glutathione cysteine ligase-modulatory subunit, glutathione cysteine ligase-catalytic subunit, and cytochrome P450 2E1 protein expressions were unchanged. Primary hepatocytes isolated from young rats treated with 10 mM acetaminophen had lower survival than those from old rats (52.4% ± 5.8%, young; 83.6% ± 1.7%, old, p < .05). The pharmacokinetic changes described may decrease susceptibility to acetaminophen-induced hepatotoxicity but may increase risk of nephrotoxicity in old age.
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Affiliation(s)
- John Mach
- Department of Clinical Pharmacology, Level 1, Acute services building, Royal North Shore Hospital, Pacific Hwy, St Leonards, NSW 2065, Australia.
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16
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Inhibition of hepatocyte autophagy increases tumor necrosis factor-dependent liver injury by promoting caspase-8 activation. Cell Death Differ 2013; 20:878-87. [PMID: 23519075 DOI: 10.1038/cdd.2013.21] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Recent investigations have demonstrated a complex interrelationship between autophagy and cell death. A common mechanism of cell death in liver injury is tumor necrosis factor (TNF) cytotoxicity. To better delineate the in vivo function of autophagy in cell death, we examined the role of autophagy in TNF-induced hepatic injury. Atg7Δhep mice with a hepatocyte-specific knockout of the autophagy gene atg7 were generated and cotreated with D-galactosamine (GalN) and lipopolysaccharide (LPS). GalN/LPS-treated Atg7Δhep mice had increased serum alanine aminotransferase levels, histological injury, numbers of TUNEL (terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling)-positive cells and mortality as compared with littermate controls. Loss of hepatocyte autophagy similarly sensitized to GalN/TNF liver injury. GalN/LPS injury in knockout animals did not result from altered production of TNF or other cytokines. Atg7Δhep mice had accelerated activation of the mitochondrial death pathway and caspase-3 and -7 cleavage. Increased cell death did not occur from direct mitochondrial toxicity or a lack of mitophagy, but rather from increased activation of initiator caspase-8 causing Bid cleavage. GalN blocked LPS induction of hepatic autophagy, and increased autophagy from beclin 1 overexpression prevented GalN/LPS injury. Autophagy, therefore, mediates cellular resistance to TNF toxicity in vivo by blocking activation of caspase-8 and the mitochondrial death pathway, suggesting that autophagy is a therapeutic target in TNF-dependent tissue injury.
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17
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Fontana L, Zhao E, Amir M, Dong H, Tanaka K, Czaja MJ. Aging promotes the development of diet-induced murine steatohepatitis but not steatosis. Hepatology 2013; 57:995-1004. [PMID: 23081825 PMCID: PMC3566282 DOI: 10.1002/hep.26099] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 10/06/2012] [Indexed: 12/11/2022]
Abstract
UNLABELLED The prevalence of the metabolic syndrome and nonalcoholic fatty liver disease (NAFLD) in humans increases with age. It is unknown whether this association is secondary to the increased incidence of risk factors for NAFLD that occurs with aging, reflects the culmination of years of exposure to lifestyle factors such as a high-fat diet (HFD), or results from physiological changes that characterize aging. To examine this question, the development of NAFLD in response to a fixed period of HFD feeding was examined in mice of different ages. Mice aged 2, 8, and 18 months were fed 16 weeks of a low-fat diet or HFD. Increased body mass and insulin insensitivity occurred in response to HFD feeding irrespective of the age of the mice. The amount of HFD-induced hepatic steatosis as determined biochemically and histologically was also equivalent among the three ages. Liver injury occurred exclusively in the two older ages as reflected by increased serum alanine aminotransferase levels, positive terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick end-labeling, and caspase activation. Older mice also had an elevated innate immune response with a more pronounced polarization of liver and adipose tissue macrophages into an M1 phenotype. Studies of cultured hepatocytes from young and old mice revealed that aged cells were selectively sensitized to the Fas death pathway. CONCLUSION Aging does not promote the development of hepatic steatosis but leads to increased hepatocellular injury and inflammation that may be due in part to sensitization to the Fas death pathway and increased M1 macrophage polarization.
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Affiliation(s)
- Luis Fontana
- Department of Medicine, Marion Bessin Liver Research Center, Diabetes Research Center and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461,Department of Biochemistry and Molecular Biology II, School of Pharmacy and the Institute of Nutrition and Food Technology, Center of Biomedical Research, University of Granada, Granada, Spain
| | - Enpeng Zhao
- Department of Medicine, Marion Bessin Liver Research Center, Diabetes Research Center and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Muhammad Amir
- Department of Medicine, Marion Bessin Liver Research Center, Diabetes Research Center and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Hanqing Dong
- Department of Medicine, Marion Bessin Liver Research Center, Diabetes Research Center and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Kathryn Tanaka
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Mark J. Czaja
- Department of Medicine, Marion Bessin Liver Research Center, Diabetes Research Center and Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461
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Bilateral ovariectomy in young rats: what happens in their livers during cecal ligation and puncture induced sepsis? J Pediatr Adolesc Gynecol 2012; 25:371-9. [PMID: 23089572 DOI: 10.1016/j.jpag.2012.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 07/06/2012] [Accepted: 07/11/2012] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE Pediatric ovarian masses comprise a heterogeneous group of benign and malignant lesions. Surgical methods consist of emergency or programmed surgery with tumoral resection and uni/bilateral oophorectomy or salpingo-oophorectomy. We examined whether bilateral ovariectomy (OVX) worsens liver injury during the onset of cecal ligation and puncture (CLP)-induced sepsis in rats. DESIGN The rat groups were: sham, bilateral-OVX, sepsis, and OVX-sepsis. SETTINGS After OVX operation, rats were allowed to recover for 12 weeks. At the end of recovery, CLP was applied 16 hours after sepsis induction. MAIN OUTCOME There was a significant difference in the numerical density of hepatocytes only between the sepsis and the OVX-sepsis groups. Serum ALT and AST were increased significantly in the OVX-sepsis group. NF-κB activation after OVX increased after induction of sepsis. OVX-sepsis group showed marked thrombosis in portal vein branches and the central vein, degeneration in the bile ducts, and widespread ischemic areas in liver sections. Intra-inflammatory cell invasion was observed in both the portal and intrasinusoidal areas. DISCUSSION This study indicates that increases in liver NF-κB activity in ovariectomized rats following CLP-induced sepsis correlates with elevated levels of serum ALT and AST and with histopathologic changes in rat liver. Bilateral OVX therefore appears to play a role in the activation of NF-κB or in production of cytokines in liver cells. Thus, we provided novel insight into the effects of OVX on liver injury following CLP-induced sepsis.
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Antioxidant Stress and Anti-Inflammation of PPARα on Warm Hepatic Ischemia-Reperfusion Injury. PPAR Res 2012; 2012:738785. [PMID: 23213319 PMCID: PMC3503442 DOI: 10.1155/2012/738785] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/27/2012] [Accepted: 10/10/2012] [Indexed: 02/07/2023] Open
Abstract
Hepatic ischemia-reperfusion (IR) injury is a serious clinical problem. Minimizing the adverse effect of ischemia-reperfusion injury after liver surgery or trauma is an urgent need. It has been proved that besides the effect of regulating the lipid and lipoprotein metabolism, PPARα also undertakes the task of organ protection. In this paper, related literature has been summarized and we come to the conclusion that administration of PPARα agonists can strengthen the antioxidant and anti-inflammation defense system by the upregulation of the expression of antioxidant enzymes and inhibition of NF-κB activity. This may provide a potential clinical treatment for hepatic ischemia-reperfusion injury.
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20
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Kim SM, Sakai T, Dang HV, Tran NH, Ono K, Ishimura K, Fukui K. Nucling, a novel protein associated with NF-κB, regulates endotoxin-induced apoptosis in vivo. J Biochem 2012; 153:93-101. [PMID: 23071121 DOI: 10.1093/jb/mvs119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Nucling is a proapoptotic protein that regulates the apoptosome and nuclear factor-kappa B (NF-κB) signalling pathways. Strong stimuli, such as Gram-negative bacterial lipopolysaccharide (LPS), induce the simultaneous secretion of cytokines following the activation of NF-κB. Proinflammatory cytokines can induce liver damage through several mechanisms such as increases in oxidative stress and apoptotic reactions leading to tissue necrosis. Herein, we show that Nucling-knockout (KO) mice are resistant to LPS that consistently caused mortality in wild-type (WT) counterparts. Although serum levels of cytokines such as tumour necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 did not differ significantly between WT and Nucling-KO mice after the LPS challenge, hepatocytes of Nucling-KO mice were refractory to LPS- or TNF-α-induced cell death. These results were consistent with the decreased expression of proapoptotic proteins including apoptosis-inducing factor and cleaved form of poly (ADP-ribose) polymerase and terminal deoxynucleotidyl transferase dUTP nick end-labelling positive cells in the liver of Nucling-KO mice after the administration of a lethal dose of LPS. Moreover, the upregulation of NF-κB-regulated anti-apoptotic molecules including cellular inhibitor of apoptosis (cIAP) 1 and cIAP2 was observed in the liver of Nucling-KO mice after LPS treatment. These findings indicate that the Nucling deficiency leads to resistance to apoptosis in liver. We propose that Nucling is important for the induction of apoptosis in cells damaged by cytotoxic stressors through the NF-κB signalling pathway.
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Affiliation(s)
- Sun Mi Kim
- Division of Enzyme Pathophysiology, The Institute for Enzyme Research (KOSOKEN), The University of Tokushima, Graduate School, 3-18-15 Kuramoto-cho, Tokushima 770-8503, Japan
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Amir M, Liu K, Zhao E, Czaja MJ. Distinct functions of JNK and c-Jun in oxidant-induced hepatocyte death. J Cell Biochem 2012; 113:3254-65. [PMID: 22644775 PMCID: PMC3636504 DOI: 10.1002/jcb.24203] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Overactivation of c-Jun N-terminal kinase (JNK)/c-Jun signaling is a central mechanism of hepatocyte injury and death including that from oxidative stress. However, the functions of JNK and c-Jun are still unclear, and this pathway also inhibits hepatocyte death. Previous studies of menadione-induced oxidant stress demonstrated that toxicity resulted from sustained JNK/c-Jun activation as death was blocked by the c-Jun dominant negative TAM67. To further delineate the function of JNK/c-Jun signaling in hepatocyte injury from oxidant stress, the effects of direct JNK inhibition on menadione-induced death were examined. In contrast to the inhibitory effect of TAM67, pharmacological JNK inhibition by SP600125 sensitized the rat hepatocyte cell line RALA255-10G to death from menadione. SP600125 similarly sensitized mouse primary hepatocytes to menadione toxicity. Death from SP600125/menadione was c-Jun dependent as it was blocked by TAM67, but independent of c-Jun phosphorylation. Death occurred by apoptosis and necrosis and activation of the mitochondrial death pathway. Short hairpin RNA knockdowns of total JNK or JNK2 sensitized to death from menadione, whereas a jnk1 knockdown was protective. Jnk2 null mouse primary hepatocytes were also sensitized to menadione death. JNK inhibition magnified decreases in cellular ATP content and β-oxidation induced by menadione. This effect mediated cell death as chemical inhibition of β-oxidation also sensitized cells to death from menadione, and supplementation with the β-oxidation substrate oleate blocked death. Components of the JNK/c-Jun signaling pathway have opposing functions in hepatocyte oxidant stress with JNK2 mediating resistance to cell death and c-Jun promoting death.
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Affiliation(s)
- Muhammad Amir
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Kun Liu
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Enpeng Zhao
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Mark J. Czaja
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
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Ji H, Shen X, Zhang Y, Gao F, Huang CY, Chang WW, Lee C, Ke B, Busuttil RW, Kupiec-Weglinski JW. Activation of cyclic adenosine monophosphate-dependent protein kinase a signaling prevents liver ischemia/reperfusion injury in mice. Liver Transpl 2012; 18:659-70. [PMID: 22290937 PMCID: PMC4186257 DOI: 10.1002/lt.23399] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Hepatic ischemia/reperfusion injury (IRI) occurs in multiple clinical settings, including liver transplantation. The cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) pathway inhibits hepatocellular apoptosis and regulates toll-like receptor 4-triggered inflammation responses in vitro. Here we examined the function and therapeutic potential of cAMP-PKA activation in a murine (C57/BL6) model of liver warm ischemia (90 minutes) followed by reperfusion. Liver IRI triggered cAMP-PKA activation, whereas the administration of its specific inhibitor, H89, exacerbated hepatocellular damage. Conversely, forskolin therapy, which activates PKA by elevating cAMP levels, protected livers from IRI; this was evidenced by diminished serum alanine aminotransferase levels and well-preserved tissue architecture. Liver protection due to cAMP-PKA stimulation was accompanied by diminished neutrophil and macrophage infiltration/activation, reduced hepatocyte necrosis/apoptosis, and increased cAMP response element-binding protein (CREB) expression and augmented interleukin-10 (IL-10) expression. The neutralization of IL-10 restored liver damage in otherwise ischemia/reperfusion-resistant, forskolin-treated mice. In vitro, cAMP-PKA activation diminished macrophage tumor necrosis factor α, IL-6, and IL-12 in an IL-10-dependent manner and prevented necrosis/apoptosis in primary mouse hepatocyte cultures. Our novel findings in a mouse model of liver IRI document the importance of cAMP-PKA signaling in hepatic homeostasis and cytoprotection in vivo. The activation of cAMP-PKA signaling differentially regulates local inflammation and prevents hepatocyte death, and this provides a rationale for novel therapeutic approaches to combating liver IRI in transplant recipients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Jerzy W. Kupiec-Weglinski
- Corresponding Author: Jerzy W. Kupiec-Weglinski, MD, PhD. Dumont-UCLA Transplant Center, 77-120 CHS, 10833 Le Conte Ave, Los Angeles, CA 90095. Phone: (310) 825-4196; Fax: (310) 267-2358;
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Proline protects liver from D-galactosamine hepatitis by activating the IL-6/STAT3 survival signaling pathway. Amino Acids 2012; 43:2371-80. [PMID: 22585093 DOI: 10.1007/s00726-012-1317-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
Abstract
The oral administration of proline, one of the non-essential amino acids, has been shown to effectively protect the liver from D-galactosamine (GalN)-induced liver injury and to improve the survival rate. The aim of this study was to investigate the mechanism of this protective action of proline. We paid particular attention to the effect of proline on inflammatory activation, regenerative response, and the associated signal transduction in the liver. Male Fischer rats received intraperitoneal injections of GalN (1.4 g/kg) with or without the oral administration of proline (2 g/kg) 1 h before GalN treatment. Liver pathology, plasma indices of inflammation, and the level of proliferative marker in the liver were monitored. The hepatic activation of interleukin-6 (IL-6)/signal transducer and activator of transcription (STAT)-3 pathway, which is downstream of tumor necrosis factor (TNF)-α/nuclear factor-κB, was also studied. GalN induced massive inflammatory expansion in the liver, leading to a high death rate (60 %) more than 72 h after the treatment. Proline administration significantly suppressed inflammatory infiltration in the live after 48 h, which was accompanied by depletion of plasma TNF-α, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase. The mRNA expression of histone H3, a marker of proliferation, was significantly upregulated in the liver of proline-treated animals. Furthermore, IL-6/STAT-3 pathway, an anti-inflammatory and regenerative signaling pathway, was strongly activated prior to these observations, with the upregulated expression of downstream genes. These results suggest that the tissue-protective mechanism of proline involves the early activation of IL-6/STAT-3 pathway in the liver, with subsequent activation of the regenerative response and suppression of massive inflammatory activation.
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Ullio C, Casas J, Brunk UT, Sala G, Fabriàs G, Ghidoni R, Bonelli G, Baccino FM, Autelli R. Sphingosine mediates TNFα-induced lysosomal membrane permeabilization and ensuing programmed cell death in hepatoma cells. J Lipid Res 2012; 53:1134-43. [PMID: 22454477 DOI: 10.1194/jlr.m022384] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Normally, cell proliferation and death are carefully balanced in higher eukaryotes, but one of the most important regulatory mechanisms, apoptosis, is upset in many malignancies, including hepatocellular-derived ones. Therefore, reinforcing cell death often is mandatory in anticancer therapy. We previously reported that a combination of tumor necrosis factor-α (TNF) and cycloheximide (CHX) efficiently kill HTC cells, a rat hepatoma line, in an apoptosis-like mode. Death is actively mediated by the lysosomal compartment, although lysosomal ceramide was previously shown not to be directly implicated in this process. In the present study, we show that TNF/CHX increase lysosomal ceramide that is subsequently converted into sphingosine. Although ceramide accumulation does not significantly alter the acidic compartment, the sphingosine therein generated causes lysosomal membrane permeabilization (LMP) followed by relocation of lysosomal cathepsins to the cytoplasm. TNF/CHX-induced LMP is effectively abrogated by siRNAs targeting acid sphingomyelinase or acid ceramidase, which prevent both LMP and death induced by TNF/CHX. Taken together, our results demonstrate that lysosomal accumulation of ceramide is not detrimental per se, whereas its degradation product sphingosine, which has the capacity to induce LMP, appears responsible for the observed apoptotic-like death.
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Affiliation(s)
- Chiara Ullio
- Department of Experimental Medicine and Oncology, University of Turin, Turin, Italy
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Yu J, Lee HS, Lee SM, Yu HC, Moon WS, Chung MJ, Park JW, Park BH. Aggravation of post-ischemic liver injury by overexpression of A20, an NF-κB suppressor. J Hepatol 2011; 55:328-36. [PMID: 21167234 DOI: 10.1016/j.jhep.2010.11.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Revised: 11/11/2010] [Accepted: 11/12/2010] [Indexed: 01/25/2023]
Abstract
BACKGROUND & AIMS A20 is an intracellular ubiquitin-editing enzyme that plays an important role in the negative feedback regulation of NF-κB activation in response to a diverse range of stimuli. Liver ischemia/reperfusion injury is associated with rapid activation of NF-κB signaling, but the role of NF-κB in hepatic ischemia/reperfusion injury remains controversial. The NF-κB signaling pathway mediates both protective and deleterious effects in the liver. Here, we examined whether A20 inhibited or aggravated hepatic ischemia/reperfusion injury. METHODS We used IκBα super-repressor as a positive control and overexpressed A20 and IκBα super-repressor in the liver of C57BL/6 mice. Mice underwent 45min of partial hepatic ischemia and were then reperfused. RESULTS Protein level of A20 was increased after reperfusion. Mice subjected to ischemia/reperfusion injury showed increased NF-κB activation, as evidenced by phosphorylation of IκBα and nuclear translocation of NF-κB. Prior transfection with Ad-A20 or Ad-IκBα super-repressor attenuated NF-κB activation and aggravated liver injury. Serum aminotransferases and proinflammatory cytokines, hepatocellular necrosis, and hepatic neutrophil infiltration were markedly increased compared to those of uninfected or control virus infected mice. In addition, A20 abolished the beneficial effect of ischemic preconditioning. CONCLUSIONS Our results suggest that inhibition of NF-κB activation by A20 aggravated partial hepatic ischemia/reperfusion injury. Understanding how the NF-κB pathway plays a role in directing a clinical outcome may lead to better prospects of more rational approaches to reduce post-ischemic liver injury.
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Affiliation(s)
- Jiahua Yu
- Department of Biochemistry, Medical School and Diabetes Research Center, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea
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Stuart WD, Kulkarni RM, Gray JK, Vasiliauskas J, Leonis MA, Waltz SE. Ron receptor regulates Kupffer cell-dependent cytokine production and hepatocyte survival following endotoxin exposure in mice. Hepatology 2011; 53:1618-28. [PMID: 21520175 PMCID: PMC3082400 DOI: 10.1002/hep.24239] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Previous studies demonstrated that targeted deletion of the Ron receptor tyrosine kinase (TK) domain in mice leads to marked hepatocyte protection in a well-characterized model of lipopolysaccharide (LPS)-induced acute liver failure in D-galactosamine (GalN)-sensitized mice. Hepatocyte protection in TK-/- mice was observed despite paradoxically elevated serum levels of tumor necrosis factor alpha (TNF-α). To understand the role of Ron in the liver, purified populations of Kupffer cells and hepatocytes from wildtype (TK+/+) and TK-/- mice were studied. Utilizing quantitative reverse-transcription polymerase chain reaction (RT-PCR), we demonstrated that Ron is expressed in these cell types. Moreover, we also recapitulated the protected hepatocyte phenotype and exaggerated cytokine production observed in the TK-/- mice in vivo through the use of purified cultured cells ex vivo. We show that isolated TK-/- Kupffer cells produce increased levels of TNF-α and select cytokines compared to TK+/+ cells following LPS stimulation. We also show that conditioned media from LPS-treated TK-/- Kupffer cells was more toxic to hepatocytes than control media, suggesting the exaggerated levels of cytokines produced from the TK-/- Kupffer cells are detrimental to wildtype hepatocytes. In addition, we observed that TK-/- hepatocytes were more resistant to cell death compared to TK+/+ hepatocytes, suggesting that Ron functions in both the epithelial and inflammatory cell compartments to regulate acute liver injury. These findings were confirmed in vivo in mice with hepatocyte and macrophage cell-type-specific conditional Ron deletions. Mice with Ron loss selectively in hepatocytes exhibited less liver damage and increased survival compared to mice with Ron loss in macrophages. CONCLUSION We dissected cell-type-specific roles for Ron such that this receptor modulates cytokine production from Kupffer cells and inhibits hepatocyte survival in response to injury.
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Affiliation(s)
- William D. Stuart
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521
| | - Rishikesh M. Kulkarni
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521
| | - Jerilyn K. Gray
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521
| | - Juozas Vasiliauskas
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521
| | - Mike A. Leonis
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521
| | - Susan E. Waltz
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267–0521, Departments of Research, Cincinnati Veterans Affairs Medical Center and Shriners Hospital for Children, Cincinnati, OH 45267–0521,Address correspondence to: Susan E. Waltz, Ph.D., Department of Cancer and Cell Biology, Vontz Center for Molecular Studies, University of Cincinnati College of Medicine, 3125 Eden Ave, Cincinnati, OH 45267–0521, Tel: 513.558.8675, Fax: 513.558.4428,
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Varela-Rey M, Beraza N, Lu SC, Mato JM, Martínez-Chantar ML. Role of AMP-activated protein kinase in the control of hepatocyte priming and proliferation during liver regeneration. Exp Biol Med (Maywood) 2011; 236:402-8. [PMID: 21427236 DOI: 10.1258/ebm.2011.010352] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The enzyme AMP-activated protein kinase (AMPK) is the main energy sensor in cells and is responsible for controlling the balance of anabolic/catabolic processes under metabolic stress conditions. This metabolic control exerted by AMPK is critical for energy-demanding situations, such as liver regeneration. Immediately after partial hepatectomy (PH), the liver undergoes the priming phase, mediated by the proinflammatory cytokines tumor necrosis factor (TNF) and interleukin-6, which promote responsiveness of hepatocytes to growth factors, such as hepatocyte growth factor (HGF) and epidermal growth factor, which lead to proliferation. In addition to its metabolic function, AMPK is likely to be a key mediator in both hepatocyte priming and the proliferative phases, induced by TNF-α and HGF, respectively. TNF-α-induced AMPK activation has been shown to be necessary for nuclear factor κappa B (NF-κB)-induced inducible nitric oxide synthase expression and for blocking TNF-α-induced apoptosis. On the other hand, HGF-induced LKB1/AMPK activation has been found to play a critical role in controlling Hu antigen R cytosolic localization and endothelial nitric oxide synthase activation, and consequently Cyclin D1 and Cyclin A expressions, and nitric oxide generation, respectively. During PH, levels of S-adenosylmethionine (SAMe), the principal methyl donor in the liver, have to decrease to allow liver proliferation. Our studies also show that SAMe inhibits hepatocyte proliferation by controlling the hepatocyte's responsiveness to mitogenic signals such as HGF through the inhibition of AMPK activity. In summary, these data highlight the essential role of AMPK in controlling the balance between hepatocyte metabolic adaptations, cell cycle progression and apoptosis during liver regeneration.
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Affiliation(s)
- Marta Varela-Rey
- CIC bioGUNE, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd), Technology Park of Bizkaia, 48160-Derio, Bizkaia, Spain.
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Identification and evaluation of neutral sphingomyelinase 2 inhibitors. Arch Pharm Res 2011; 34:229-36. [DOI: 10.1007/s12272-011-0208-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 11/03/2010] [Accepted: 11/06/2010] [Indexed: 02/02/2023]
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Luedde T, Schwabe RF. NF-κB in the liver--linking injury, fibrosis and hepatocellular carcinoma. Nat Rev Gastroenterol Hepatol 2011; 8:108-18. [PMID: 21293511 PMCID: PMC3295539 DOI: 10.1038/nrgastro.2010.213] [Citation(s) in RCA: 982] [Impact Index Per Article: 75.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Hepatic cirrhosis and hepatocellular carcinoma (HCC) are the most common causes of death in patients with chronic liver disease. Chronic liver injury of virtually any etiology triggers inflammatory and wound-healing responses that in the long run promote the development of hepatic fibrosis and HCC. Here, we review the role of the transcription factor nuclear factor-κB (NF-κB), a master regulator of inflammation and cell death, in the development of hepatocellular injury, liver fibrosis and HCC, with a particular focus on the role of NF-κB in different cellular compartments of the liver. We propose that NF-κB acts as a central link between hepatic injury, fibrosis and HCC, and that it may represent a target for the prevention or treatment of liver fibrosis and HCC. However, NF-κB acts as a two-edged sword and inhibition of NF-κB may not only exert beneficial effects but also negatively impact hepatocyte viability, especially when NF-κB inhibition is pronounced. Finding appropriate targets or identifying drugs that either exert only a moderate effect on NF-κB activity or that can be specifically delivered to nonparenchymal cells will be essential to avoid the increase in liver injury associated with complete NF-κB blockade in hepatocytes.
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The role of glucagon-like peptide-2 on apoptosis, cell proliferation, and oxidant-antioxidant system at a mouse model of intestinal injury induced by tumor necrosis factor-alpha/actinomycin D. Mol Cell Biochem 2010; 350:13-27. [PMID: 21153865 DOI: 10.1007/s11010-010-0678-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Accepted: 12/02/2010] [Indexed: 12/18/2022]
Abstract
Tumor necrosis factor-alpha (TNF-α) is a multifunctional cytokine, which has the ability to produce cytotoxicity via induction of cell death and cell cycle arrest. Blocking the synthesis of protective proteins through a transcriptional inhibitor such as actinomycin D (Act D) sensitizes many cell types to TNF-α toxicity. Teduglutide, h[Gly(2)]GLP-2, is a protease-resistant synthetic analog of glucagon-like peptide-2 (GLP-2) which is an intestinotrophic peptide. In this study, we evaluated this potential of GLP-2 on apoptosis, cell proliferation, and oxidant-antioxidant system on a mouse model of intestinal injury induced by TNF-α/Act D. The intestinal injury was induced by intraperitoneal administration of 15 μg/kg TNF-α and 800 μg/kg Act D per mouse. Animals were injected subcutaneously 200 μg/kg h[Gly(2)]GLP-2 every 12 h for 10 consecutive days prior to the administration of TNF-α and Act D. The model of intestinal injury induced by TNF-α/Act D, which is the new animal model for the intestinal disorders, was characterized by the degeneration of intestinal mucosa, an increase in apoptotic index, expression of active caspase-3, lipid peroxidation and glutathione (GSH) levels, glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities; a decrease in cell proliferation and catalase (CAT) activity. h[Gly(2)]GLP-2 pretreatment prevented the TNF-α/Act D-induced oxidative injury by a significant reduction in the intestinal injury, apoptotic index, expression of active caspase-3, lipid peroxidation and GSH levels, GPx and SOD activities; a markedly increase in cell proliferation, and CAT activity. These results demonstrate that GLP-2 has a protective, antiapoptotic, proliferative, and antioxidant effects against to TNF-α/Act D-induced intestinal injury. It is suggested that GLP-2 may potentially be useful as a therapeutic agent in TNF-α-mediated intestinal disorders.
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Martínez-Clemente M, Ferré N, Titos E, Horrillo R, González-Périz A, Morán-Salvador E, López-Vicario C, Miquel R, Arroyo V, Funk CD, Clària J. Disruption of the 12/15-lipoxygenase gene (Alox15) protects hyperlipidemic mice from nonalcoholic fatty liver disease. Hepatology 2010; 52:1980-91. [PMID: 20967760 DOI: 10.1002/hep.23928] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 08/10/2010] [Indexed: 12/19/2022]
Abstract
UNLABELLED We have shown that Alox15, the gene encoding for 12/15-lipoxygenase (12/15-LO), is markedly up-regulated in livers from apolipoprotein E-deficient (ApoE(-/-)) mice, which spontaneously develop nonalcoholic fatty liver disease secondary to hyperlipidemia. In the current study, we used ApoE(-/-) mice with a targeted disruption of the Alox15 gene to assess the role of 12/15-LO in the development and progression of hepatic steatosis and inflammation. Compared with ApoE(-/-) mice, which exhibited extensive hepatic lipid accumulation and exacerbated inflammatory injury, ApoE/12/15-LO double-knockout (ApoE(-/-)/12/15-LO(-/-)) mice showed reduced serum alanine aminotransferase levels; decreased hepatic steatosis, inflammation, and macrophage infiltration; and decreased fatty acid synthase, tumor necrosis factor α (TNFα), monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-18, and IL-6 expression. Remarkably, disruption of Alox15 attenuated glucose intolerance and high-fat diet-induced insulin resistance, up-regulated insulin receptor substrate-2, and exerted opposite effects on hepatic c-Jun amino-terminal kinase and adenosine monophosphate-activated protein kinase phosphorylation, known negative and positive regulators of insulin signaling, respectively. In adipose tissue, the absence of Alox15 induced significant reductions in the expression of the proinflammatory and insulin-resistant adipokines MCP-1, TNFα, and resistin while increasing the expression of glucose transporter-4. Interestingly, compared with ApoE(-/-) mice, which exhibited increased hepatic caspase-3 staining, ApoE(-/-)/12/15-LO(-/-) mice showed attenuated hepatocellular injury. Consistent with this finding, hepatocytes isolated from ApoE(-/-) mice were more vulnerable to TNFα-induced programmed cell death, an effect that was not observed in hepatocytes carrying a targeted disruption of the Alox15 gene. CONCLUSION Collectively, our data suggest a potentially relevant mechanism linking 12/15-LO to the promotion of hepatic steatosis, insulin resistance, and inflammation in experimental liver disease of metabolic origin.
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Affiliation(s)
- Marcos Martínez-Clemente
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, Centro de Investigaciones Biomédicas Esther Koplowitz, Institut d'Investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Spain
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Wang Y, Singh R, Xiang Y, Greenbaum LE, Czaja MJ. Nuclear factor κB up-regulation of CCAAT/enhancer-binding protein β mediates hepatocyte resistance to tumor necrosis factor α toxicity. Hepatology 2010; 52:2118-26. [PMID: 20979051 PMCID: PMC2991433 DOI: 10.1002/hep.23929] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Accepted: 08/10/2010] [Indexed: 12/17/2022]
Abstract
UNLABELLED The sensitization of hepatocytes to cell death from tumor necrosis factor α (TNFα) underlies many forms of hepatic injury, including that from toxins. Critical for hepatocyte resistance to TNFα toxicity is activation of nuclear factor κB (NF-κB) signaling, which prevents TNFα-induced death by the up-regulation of protective proteins. To further define the mechanisms of hepatocyte sensitization to TNFα killing, immunoblot analysis comparing livers from mice treated with lipopolysaccharide (LPS) alone or LPS together with the hepatotoxin galactosamine (GalN) was performed to identify TNFα-induced protective proteins blocked by GalN. Levels of CCAAT/enhancer-binding protein β (C/EBPβ) were increased after LPS treatment but not GalN/LPS treatment. In a nontransformed rat hepatocyte cell line, TNFα-induced increases in C/EBPβ protein levels were dependent on NF-κB-mediated inhibition of proteasomal degradation. Pharmacological inhibition of c-Jun N-terminal kinase (JNK) did not affect C/EBPβ degradation, indicating that the process was JNK-independent. C/EBPβ functioned to prevent cell death as adenoviral C/EBPβ overexpression blocked TNFα-induced apoptosis in cells sensitized to TNFα toxicity by NF-κB inhibition. C/EBPβ inhibited TNFα-induced caspase 8 activation and downstream mitochondrial cytochrome c release and caspase 3 and caspase 7 activation. Studies in primary hepatocytes from c/ebpβ(-/-) mice confirmed that loss of C/EBPβ increased death from TNFα. c/ebpβ(-/-) mice were also sensitized to liver injury from a nontoxic dose of LPS or TNFα. The absence of jnk2 failed to reverse the GalN-induced block in C/EBPβ induction by LPS, again demonstrating that C/EBPβ degradation was JNK-independent. CONCLUSION C/EBPβ is up-regulated by TNFα and mediates hepatocyte resistance to TNFα toxicity by inhibiting caspase-dependent apoptosis. In the absence of NF-κB signaling, proteasomal degradation of C/EBPβ is increased by a JNK-independent mechanism and promotes death from TNFα.
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Affiliation(s)
- Yongjun Wang
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Rajat Singh
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Youqing Xiang
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Linda E. Greenbaum
- Departments of Cancer Biology and Medicine, Jefferson Medical College, Philadelphia, PA 19107
| | - Mark J. Czaja
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, NY 10461
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Roy DN, Mandal S, Sen G, Mukhopadhyay S, Biswas T. 14-Deoxyandrographolide desensitizes hepatocytes to tumour necrosis factor-alpha-induced apoptosis through calcium-dependent tumour necrosis factor receptor superfamily member 1A release via the NO/cGMP pathway. Br J Pharmacol 2010; 160:1823-43. [PMID: 20649583 DOI: 10.1111/j.1476-5381.2010.00836.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Andrographis paniculata (AP) has been found to display hepatoprotective effect, although the mechanism of action of the active compounds of AP in this context still remains unclear. Here, we evaluated the hepatoprotective efficacy of 14-deoxyandrographolide (14-DAG), a bioactive compound of AP, particularly its role in desensitization of hepatocytes to tumour necrosis factor-alpha (TNF-alpha)-induced signalling of apoptosis. EXPERIMENTAL APPROACH TNF-alpha-mediated ligand receptor interaction in hepatocytes in the presence of 14-DAG was studied in vitro in primary hepatocyte cultures, with the help of co-immunoprecipitation, confocal microscopy and FACS analysis. Events associated with 14-DAG-induced TNFRSF1A release from hepatocytes were determined using immunoblotting, biochemical assay and fluorimetric studies. Pulse-chase experiments with radiolabelled TNF-alpha and detection of apoptotic nuclei by terminal transferase-mediated dUTP nick-end labelling were performed under in vivo conditions. KEY RESULTS 14-DAG down-regulated the formation of death-inducing signalling complex, resulting in desensitization of hepatocytes to TNF-alpha-induced apoptosis. Pretreatment of hepatocytes with 14-DAG accentuated microsomal Ca-ATPase activity through induction of NO/cGMP pathway. This resulted in enhanced calcium influx into microsomal lumen with the formation of TNFRSF1A-ARTS-1-NUCB2 complex in cellular vesicles. It was followed by the release of full-length 55 kDa TNFRSF1A and a reduction in the number of cell surface TNFRSF1A, which eventually caused diminution of TNF-alpha signal in hepatocytes. CONCLUSION AND IMPLICATION Taken together, the results demonstrate for the first time that 14-DAG desensitizes hepatocytes to TNF-alpha-mediated apoptosis through the release of TNFRSF1A. This can be used as a strategy against cytokine-mediated hepatocyte apoptosis in liver dysfunctions.
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Affiliation(s)
- D N Roy
- Cell Biology and Physiology Division, Indian Institute of Chemical Biology, A Unit of Council of Scientific and Industrial Research, Kolkata, India
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Genipin protects lipopolysaccharide-induced apoptotic liver damage in D-galactosamine-sensitized mice. Eur J Pharmacol 2010; 635:188-93. [PMID: 20303938 DOI: 10.1016/j.ejphar.2010.03.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 02/12/2010] [Accepted: 03/03/2010] [Indexed: 12/15/2022]
Abstract
This study examined the effects of genipin, isolated from Gardenia jasminoides Ellis, on d-galactosamine (GalN) and lipopolysaccharide (LPS)-induced hepatic apoptosis and liver failure. Mice were given an intraperitoneal injection of genipin (25, 50, 100 and 200mg/kg) 1h before GalN (700mg/kg)/LPS (10microg/kg) administration. The survival rate of the genipin group was significantly higher than that of the control. Genipin markedly reduced the increases in serum aminotransferase activities and lipid peroxidation. The glutathione content decreased in GalN/LPS group, and this decrease was attenuated by genipin. Increases in serum tumor necrosis factor-alpha (TNF-alpha), which were observed in GalN/LPS-treated mice, were significantly reduced by genipin. Genipin attenuated the GalN/LPS-induced apoptosis of hepatocytes, as estimated by the caspase-3 and -8 activity assay, TNF-R1 associated death domain (TRADD) protein measurement and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) method. Moreover, increased cytosolic cytochrome c protein was reduced by genipin. After 3h of GalN/LPS injection, nuclear phosphorylated c-Jun (p-c-Jun) level was significantly increased, whereas it was attenuated by genipin. Also, the increased nuclear level of nuclear factor-kappaB and the decreased cytosolic level of IkappaB-alpha protein were significantly attenuated by genipin. Our results suggest that genipin offers marked hepatoprotection against damage induced by GalN/LPS related with its antioxidative, anti-apoptotic activities, and inhibition of NF-kappaB nuclear translocation and nuclear p-c-Jun expression.
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Martínez-Clemente M, Ferré N, González-Périz A, López-Parra M, Horrillo R, Titos E, Morán-Salvador E, Miquel R, Arroyo V, Funk CD, Clària J. 5-lipoxygenase deficiency reduces hepatic inflammation and tumor necrosis factor alpha-induced hepatocyte damage in hyperlipidemia-prone ApoE-null mice. Hepatology 2010; 51:817-27. [PMID: 20112424 DOI: 10.1002/hep.23463] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
UNLABELLED The actual risk factors that drive hepatic inflammation during the transition from steatosis to steatohepatitis are unknown. We recently demonstrated that hyperlipidemia-prone apolipoprotein E-deficient (ApoE(-/-)) mice exhibit hepatic steatosis and increased susceptibility to hepatic inflammation and advanced fibrosis. Because the proinflammatory 5-lipoxygenase (5-LO) pathway was found to be up-regulated in these mice and given that 5-LO deficiency confers cardiovascular protection to ApoE(-/-) mice, we determined the extent to which the absence of 5-LO would alter liver injury in these mice. Compared with ApoE(-/-) mice, which showed expected hepatic steatosis and inflammation, ApoE/5-LO double-deficient (ApoE(-/-)/5-LO(-/-)) mice exhibited reduced hepatic inflammation, macrophage infiltration, tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein-1 (MCP-1) and interleukin (IL)-18 expression, caspase-3 and nuclear factor-kappaB (NF-kappaB) activities, and serum alanine aminotransferase levels in the absence of changes in hepatic steatosis. The lack of 5-LO produced a remarkable insulin-sensitizing effect in the adipose tissue because peroxisome proliferator-activated receptor gamma, insulin receptor substrate-1, and adiponectin were up-regulated, whereas c-Jun amino-terminal kinase phosphorylation and MCP-1 and IL-6 expression were down-regulated. On the other hand, hepatocytes isolated from ApoE(-/-)/5-LO(-/-) mice were more resistant to TNF-alpha-induced apoptosis. The 5-LO products leukotriene (LT) B(4), LTD(4), and 5-HETE consistently triggered TNF-alpha-induced apoptosis and compromised hepatocyte survival by suppressing NF-kappaB activity in the presence of actinomycin D. Moreover, ApoE(-/-)/5-LO(-/-) mice were protected against sustained high-fat diet (HFD)-induced liver injury and hepatic inflammation, macrophage infiltration and insulin resistance were significantly milder than those of ApoE(-/-) mice. Finally, pharmacological inhibition of 5-LO significantly reduced hepatic inflammatory infiltrate in the HFD and ob/ob models of fatty liver disease. CONCLUSION These combined data indicate that hyperlipidemic mice lacking 5-LO are protected against hepatic inflammatory injury, suggesting that 5-LO is involved in mounting hepatic inflammation in metabolic disease.
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Affiliation(s)
- Marcos Martínez-Clemente
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, Centro de Investigación Biomédica Esther Koplowitz, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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Ruff AL, Dillman JF. Sulfur mustard induced cytokine production and cell death: Investigating the potential roles of the p38, p53, and NF-κB signaling pathways with RNA interference. J Biochem Mol Toxicol 2010; 24:155-64. [DOI: 10.1002/jbt.20321] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
The liver is a central regulator of glucose homeostasis and stores or releases glucose according to metabolic demands. In insulin resistant states or diabetes the dysregulation of hepatic glucose release contributes significantly to the pathophysiology of these conditions. Acute or chronic liver disease can aggravate insulin resistance and the physiological effects of insulin on hepatocytes are disturbed. Insulin resistance has also been recognized as an independent risk factor for the development of liver injury. In the healthy liver tissue homeostasis is achieved through cell turnover by apoptosis and dysregulation of the physiological process resulting in too much or too little cell death can have potentially devastating effects on liver tissue. The delineation of the signaling pathways that mediate apoptosis changed the paradigms of understanding of many liver diseases. These signaling events include cell surface based receptor-ligand systems and intracellular signaling pathways that are regulated through kinases on multiple levels. The dissection of these signaling pathways has shown that the regulators of apoptosis signaling events in hepatocytes can also modulate insulin signaling pathways and that mediators of insulin resistance in turn influence liver cell apoptosis. This review will summarize the potential crosstalk between apoptosis and insulin resistance signaling events and discuss the involved mediators.
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Affiliation(s)
- Jörn M Schattenberg
- I. Medizinsiche Klinik, University Medical Center of the Johannes Gutenberg University, Langenbeckstrasse 1, 55131 Mainz, Germany.
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Singh R, Wang Y, Schattenberg JM, Xiang Y, Czaja MJ. Chronic oxidative stress sensitizes hepatocytes to death from 4-hydroxynonenal by JNK/c-Jun overactivation. Am J Physiol Gastrointest Liver Physiol 2009; 297:G907-17. [PMID: 20501438 PMCID: PMC2777462 DOI: 10.1152/ajpgi.00151.2009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Sustained activation of the c-Jun NH(2)-terminal kinase (JNK) signaling pathway mediates the development and progression of experimental diet-induced nonalcoholic fatty liver disease (NAFLD). Delineating the mechanism of JNK overactivation in the setting of a fatty liver is therefore essential to understanding the pathophysiology of NAFLD. Both human and experimental NAFLD are associated with oxidative stress and resultant lipid peroxidation, which have been proposed to mediate the progression of this disease from simple steatosis to steatohepatitis. The ability of oxidants and the lipid peroxidation product 4-hydroxynonenal (HNE) to activate JNK signaling suggested that these two factors may act synergistically to trigger JNK overactivation. The effect of HNE on hepatocyte injury and JNK activation was therefore examined in cells under chronic oxidant stress from overexpression of the prooxidant enzyme cytochrome P450 2E1 (CYP2E1), which occurs in NAFLD. CYP2E1-generated oxidant stress sensitized a rat hepatocyte cell line to death from normally nontoxic concentrations of HNE. CYP2E1-overexpressing cells underwent a more profound depletion of glutathione (GSH) in response to HNE secondary to decreased gamma-glutamylcysteine synthetase activity. GSH depletion led to overactivation of JNK/c-Jun signaling at the level of mitogen-activated protein kinase kinase 4 that induced cell death. Oxidant stress and the lipid peroxidation product HNE cause synergistic overactivation of the JNK/c-Jun signaling pathway in hepatocytes, demonstrating that HNE may not be just a passive biomarker of hepatic oxidant stress but rather an active mediator of hepatocellular injury through effects on JNK signaling.
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Affiliation(s)
- Rajat Singh
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Yongjun Wang
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Jörn M. Schattenberg
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Youqing Xiang
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Mark J. Czaja
- Department of Medicine and Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York
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Marcos M, Pastor I, González-Sarmiento R, Laso FJ. A functional polymorphism of the NFKB1 gene increases the risk for alcoholic liver cirrhosis in patients with alcohol dependence. Alcohol Clin Exp Res 2009; 33:1857-62. [PMID: 19673747 DOI: 10.1111/j.1530-0277.2009.01023.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The genetic basis for the predisposition to alcoholic liver cirrhosis (ALC) remains unknown. Increasing evidence supports a role for the nuclear factor (NF)-kappaB, the NF-kappaB inhibitor alpha (NFKBIA), and the peroxisome proliferator-activated receptor (PPAR)-gamma in the pathogenesis of alcoholic liver disease, raising the possibility that common polymorphisms in genes encoding these molecules may confer susceptibility to ALC. The objective of this study was to analyze the relationship between common polymorphisms in NFKB1, NFKBIA, and PPARG2 genes and the presence of ALC. METHODS A total of 258 male alcoholics (161 without liver disease and 97 with ALC) and 101 healthy controls were genotyped for the -94ins/delATTG NFKB1, 3'-UTR+126G>A NFKBIA, and 34C>G PPARG2 polymorphisms. The association of these genetic variants with ALC was tested in alcoholic patients with alcohol abuse and alcohol dependence. A logistic regression analysis was further performed to analyze the model of inheritance. RESULTS We found an association between the presence of the deletion allele in NFKB1 polymorphism and ALC in patients with alcohol dependence. We found no association between NFKBIA and PPARG2 polymorphisms and the presence of ALC. CONCLUSIONS The deletion allele of the -94ins/del NFKB1 polymorphism could be associated with a higher risk of developing ALC through an increase in inflammation, as supported by previous data.
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Affiliation(s)
- Miguel Marcos
- The Unidad de Alcoholismo, Servicio de Medicina Interna II, Hospital Universitario de Salamanca, Spain
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Kuboki S, Sakai N, Clarke C, Schuster R, Blanchard J, Edwards MJ, Lentsch AB. The peptidyl-prolyl isomerase, Pin1, facilitates NF-kappaB binding in hepatocytes and protects against hepatic ischemia/reperfusion injury. J Hepatol 2009; 51:296-306. [PMID: 19515451 PMCID: PMC2747648 DOI: 10.1016/j.jhep.2009.04.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Revised: 04/03/2009] [Accepted: 04/27/2009] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIMS Our previous work suggested an important role for the peptidyl-prolyl isomerase, Pin1, in hepatic NF-kappaB activation and liver injury during ischemia/reperfusion (I/R). In this study, we sought to determine the function of Pin1 in the injury response to hepatic I/R. METHODS Wild-type and Pin1(-/-) mice were subjected to partial hepatic I/R. In addition, hepatocytes and Kupffer cells were isolated from these mice. RESULTS Pin1(-/-) mice had reduced hepatic NF-kappaB activation and more liver injury after I/R than wild-type mice. The increased injury was not a result of enhanced inflammation as Pin1(-/-) mice had the same level of proinflammatory cytokine production and less neutrophil accumulation in the liver. The reduced NF-kappaB activation was not a result of a defect in nuclear translocation of NF-kappaB. In fact, hepatic nuclear p65 protein expression was higher in Pin1(-/-) mice than wild-type mice. This suggests that Pin1 is important for NF-kappaB-DNA binding. This effect was specific to hepatocytes as isolated Kupffer cells from wild-type and Pin1(-/-) mice were identical in their activation of NF-kappaB and production of cytokines after stimulation. In contrast, hepatocytes stimulated with TNFalpha had greatly reduced NF-kappaB activation, reduced production of the CXC chemokine, MIP-2, and increased cell death. CONCLUSIONS These data suggest that Pin1 is a critical regulator of NF-kappaB activation in hepatocytes and its role in these cells appears to confer direct protective effects.
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Affiliation(s)
- Satoshi Kuboki
- The Laboratory of Trauma, Sepsis & Inflammation Research, Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267-0558, USA
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Gürleyen H, Christiansen H, Tello K, Dudas J, Hermann RM, Rave-Fränk M, Hess CF, Ramadori G, Saile B. Irradiation leads to sensitization of hepatocytes to TNF-alpha-mediated apoptosis by upregulation of IkappaB expression. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2009; 48:85-94. [PMID: 18956207 DOI: 10.1007/s00411-008-0200-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/09/2008] [Indexed: 05/27/2023]
Abstract
This study aimed to reveal the pathophysiological signalling responsible for radiation-induced sensitization of hepatocytes to TNF-alpha-mediated apoptosis. IkappaB was upregulated in irradiated hepatocytes. Administration of IkappaB antisense oligonucleotides prior to irradiation inhibited occurrence of apoptosis after TNF-alpha administration. Caspases-8, -9 and -3 activities were increased in irradiated hepatocytes and downregulation of apoptosis by IkappaB antisense oligonucleotides was mediated by suppression of caspases-9 and -3 activation but not of caspase-8 activation, suggesting that radiation-induced sensitization of hepatocytes to TNF-alpha-mediated apoptosis additionally requires changes upstream of caspase-8 activation. Herein, upregulation of FLIP may play a crucial role. Cleavage of bid, upregulation of bax, downregulation of bcl-2 and release of cytochrome c after TNF-alpha-administration depend on radiation-induced upregulation of IkappaB, thus demonstrating an apoptosis permitting effect of IkappaB.
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Affiliation(s)
- Hakan Gürleyen
- Section of Gastroenterology and Endocrinology, Department of Internal Medicine, Universitätsmedizin Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany
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The Role of NF-kappaB in PPARalpha-Mediated Hepatocarcinogenesis. PPAR Res 2009; 2008:286249. [PMID: 19197377 PMCID: PMC2633453 DOI: 10.1155/2008/286249] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 10/03/2008] [Accepted: 11/03/2008] [Indexed: 01/04/2023] Open
Abstract
In this review, the role of NF-kappaB in the induction of hepatocarcinogenesis by peroxisome proliferators is examined. The administration of peroxisome proliferators for more than a three-day period leads to the activation of NF-kappaB in the livers of rats and mice. On the other hand, peroxisome proliferator activated receptor-alpha (PPARalpha) activation in non-hepatic tissues can lead to the inhibition of NF-kappaB activation. Several lines of evidence support the hypothesis that the activation of NF-kappaB by peroxisome proliferators in the liver is mediated by oxidative stress. The role of NF-kappaB in peroxisome proliferator-induced hepatocarcinogenesis has been examined using NF-kappaB knockout models. Specifically, the induction of cell proliferation and the promotion of liver carcinogenesis are inhibited in mice lacking the p50 subunit of NF-kappaB. Overall, the activation of NF-kappaB appears to be important in the carcinogenic activity of peroxisome proliferators.
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Abstract
Uncontrolled production of collagen I is the main feature of liver fibrosis. Following a fibrogenic stimulus such as alcohol, hepatic stellate cells (HSC) transform into an activated collagen-producing cell. In alcoholic liver disease, numerous changes in gene expression are associated with HSC activation, including the induction of several intracellular signaling cascades, which help maintain the activated phenotype and control the fibrogenic and proliferative state of the cell. Detailed analyses for understanding the molecular basis of the collagen I gene regulation have revealed a complex process involving reactive oxygen species (ROS) as key mediators. Less is known, however, about the contribution of reactive nitrogen species (RNS). In addition, a series of cytokines, growth factors, and chemokines, which activate extracellular matrix (ECM)-producing cells through paracrine and autocrine loops, contribute to the fibrogenic response.
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Affiliation(s)
- R. Urtasun
- Mount Sinai School of Medicine, Box 1123, Department of Medicine/Division of Liver Diseases, 1425 Madison Avenue, Room 11-76, New York, NY 10029, USA
| | - L. Conde de la Rosa
- Mount Sinai School of Medicine, Box 1123, Department of Medicine/Division of Liver Diseases, 1425 Madison Avenue, Room 11-76, New York, NY 10029, USA
| | - N. Nieto
- Mount Sinai School of Medicine, Box 1123, Department of Medicine/Division of Liver Diseases, 1425 Madison Avenue, Room 11-76, New York, NY 10029, USA
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Kassardjian A, Kreydiyyeh SI. JNK modulates the effect of caspases and NF‐κB in the TNF‐α‐induced down‐regulation of Na+/K+ATPase in HepG2 cells. J Cell Physiol 2008; 216:615-20. [DOI: 10.1002/jcp.21436] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Transfection of NF-kappaB decoy oligodeoxynucleotides into macrophages reduces murine fatal liver failure after excessive hepatectomy. J Surg Res 2008; 154:179-86. [PMID: 19041101 DOI: 10.1016/j.jss.2008.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 06/05/2008] [Accepted: 07/02/2008] [Indexed: 11/21/2022]
Abstract
BACKGROUND Macrophages play an important role in the initiation of hypercytokinemia, which is involved in the development of liver failure after excessive hepatectomy. This study was aimed at evaluating whether the selective suppression of nuclear factor kappa B (NF-kappaB) in macrophages by decoy oligodeoxynucleotides (ODN) could prevent liver failure after excessive hepatectomy. MATERIALS AND METHODS Ninety percent hepatectomy was performed in 8-wk-old mice. NF-kappaB/decoy/ODN was transfected into the liver by the hemagglutinating virus of Japan-liposome method. The survival rate, serum levels of interleukin (IL)-1beta IL-6, and tumor necrosis factor-alpha, and the histological findings in the remnant liver were compared between the 90%-hepatectomized mice transfected with the decoy ODN (decoy group) and the 90%-hepatectomized mice injected with saline (control group). RESULT The control group mice died within 48 h of the operation, while the survival rate in the decoy group at 48 h after the operation was 35%, and at 2 wk, 15%. The serum levels of all cytokines were significantly lower in the decoy group than in the control group. The number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive cells in the remnant liver was smaller in the decoy group. CONCLUSION Transfection of NF-kappaB/decoy/ODN reduces fatal liver failure in mice after excessive hepatectomy by suppressing hypercytokinemia, but offers only a low rate of survival.
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Inhibition of the promotion of hepatocarcinogenesis by 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) by the deletion of the p50 subunit of NF-kappa B in mice. Toxicol Appl Pharmacol 2008; 232:302-8. [PMID: 18644402 DOI: 10.1016/j.taap.2008.06.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/12/2008] [Accepted: 06/24/2008] [Indexed: 02/07/2023]
Abstract
Polychlorinated biphenyls (PCBs) are persistent and ubiquitous environmental chemicals that bioaccumulate and have hepatic tumor promoting activity in rodents. The present study examined the effect of deleting the p50 subunit of NF-kappaB on the hepatic tumor promoting activity of 2,2',4,4',5,5'-hexachlorobiphenyl (PCB-153) in mice. Both wild-type and p50-/- male mice were injected i.p. with diethylnitrosamine (DEN, 90 mg/kg) and then subsequently injected biweekly with 20 i.p. injections of PCB-153 (300 micromol/kg/injection). p50 deletion decreased the tumor incidence in both PCB- and vehicle-treated mice, whereas PCB-153 slightly (P=0.09) increased the tumor incidence in wild-type and p50-/- mice. PCB-153 increased the total tumor volume in both wild-type and p50-/- mice, but the total tumor volume was not affected by p50 deletion in either PCB- or vehicle-treated mice. The volume of tumors that were positive for glutamine synthetase (GS), which is indicative of mutations in the beta-catenin gene, was increased in both wild-type and p50-/- mice administered PCB-153 compared to vehicle controls, and inhibited in p50-/- mice compared to wild-type mice (in both PCB- and vehicle-treated mice). The volume of tumors that were negative for GS was increased in p50-/- mice compared to wild-type mice but was not affected by PCB-153. PCB-153 increased cell proliferation in normal hepatocytes in wild-type but not p50-/- mice; this increase was inhibited in p50-/- mice. In hepatic tumors, the rate of cell proliferation was much higher than in normal hepatocytes, but was not affected by PCB treatment or p50 deletion. The rate of apoptosis, as measured by the TUNEL assay, was not affected by PCB-153 or p50 deletion in normal hepatocytes. In hepatic tumors, the rate of apoptosis was lower than in normal hepatocytes; PCB-153 slightly (P=0.10) increased apoptosis in p50-/- but not wild-type mice; p50 deletion had no effect. Taken together, these data indicate that the absence of the NF-kappaB p50 subunit inhibits the promoting activity of PCB-153 and alters the proliferative and apoptotic changes in mouse liver in the response to PCBs.
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Manu KA, Kuttan G. Ursolic acid induces apoptosis by activating p53 and caspase-3 gene expressions and suppressing NF-kappaB mediated activation of bcl-2 in B16F-10 melanoma cells. Int Immunopharmacol 2008; 8:974-81. [PMID: 18486908 DOI: 10.1016/j.intimp.2008.02.013] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 02/28/2008] [Accepted: 02/28/2008] [Indexed: 11/22/2022]
Abstract
The objective of this study was to assess the effect of ursolic acid, a triterpene on inducing apoptosis in B16F-10 melanoma cells. Treatment of B16F-10 cells with nontoxic concentration of ursolic acid showed the presence of apoptotic bodies and induced DNA fragmentation in a dose depended manner. The apoptotic genes p53 and caspase-3 were found to be upregulated while the anti-apoptotic gene bcl-2 was down regulated in ursolic acid treated cells. The transcription factors NF-kappaBp65, NF-kappaBp50, NF-kappaBc-Rel, c-FOS, ATF-2 and CREB-1 were found to be inhibited significantly (p<0.001) in ursolic acid treated cells compared to untreated control. The pro-inflammatory cytokine production and gene expression of TNF-alpha, IL-1beta, IL-6 and GM-CSF were down regulated in ursolic acid treated cells compared to nontreated B16F-10 metastatic melanoma cells. All these results demonstrate that ursolic acid induce apoptosis via inhibition of NF-kappaB induced bcl-2 mediated anti-apoptotic pathway and subsequent activation of p53 mediated and TNF-alpha induced caspase-3 mediated pro-apoptotic pathways.
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Affiliation(s)
- K A Manu
- Amala Cancer Research Centre, Amala Nagar, Thrissur-680555, Kerala State, India
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Lu JW, Wang H, Yan-Li J, Zhang C, Ning H, Li XY, Zhang H, Duan ZH, Zhao L, Wei W, Xu DX. Differential effects of pyrrolidine dithiocarbamate on TNF-alpha-mediated liver injury in two different models of fulminant hepatitis. J Hepatol 2008; 48:442-52. [PMID: 18215436 DOI: 10.1016/j.jhep.2007.10.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2007] [Revised: 10/10/2007] [Accepted: 10/25/2007] [Indexed: 02/07/2023]
Abstract
BACKGROUND/AIMS Pyrrolidine dithiocarbamate (PDTC) is an inhibitor of nuclear factor kappa B (NF-kappaB) activation. The present study aimed to investigate the effects of PDTC on lipopolysaccharide (LPS)-induced liver injury in two different models of fulminant hepatitis. METHODS Mice infected with Bacillus Calmette Guerin (BCG) were challenged with LPS (0.2 mg/kg) to induce the model of inflammatory liver injury. Mice were injected with D-galactosamine (GalN, 600 mg/kg) and LPS (20 microg/kg) to induce the model of apoptotic liver injury. In the treatment groups, mice were pre-treated with PDTC (100 mg/kg), initiated 24 h prior to LPS. RESULTS PDTC pretreatment reduced the infiltration of inflammatory cells, inhibited NF-kappaB activation and the expression of tumor necrosis factor alpha (TNF-alpha), attenuated nitric oxide production, and alleviated hepatic glutathione depletion. Correspondingly, PDTC reduced serum alanine aminotransferase, improved hepatic necrosis, and prolonged the survival in the BCG/LPS model. Conversely, PDTC accelerated death and aggravated liver apoptosis in the GalN/LPS model, although it reduced nitric oxide production, attenuated glutathione depletion, and inhibited the expression of TNF-alpha in liver. CONCLUSIONS PDTC protects mice against BCG/LPS-induced inflammatory liver injury through the repression of NF-kappaB-mediated TNF-alpha release, while it seems to be detrimental in GalN/LPS-induced apoptotic liver damage.
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Affiliation(s)
- Jin-Wei Lu
- Department of Toxicology, Anhui Medical University, Hefei, China
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Wang Y, Singh R, Massey AC, Kane SS, Kaushik S, Grant T, Xiang Y, Cuervo AM, Czaja MJ. Loss of macroautophagy promotes or prevents fibroblast apoptosis depending on the death stimulus. J Biol Chem 2008; 283:4766-77. [PMID: 18073215 PMCID: PMC2754125 DOI: 10.1074/jbc.m706666200] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Macroautophagy has been implicated as a mechanism of cell death. However, the relationship between this degradative pathway and cell death is unclear as macroautophagy has been shown recently to protect against apoptosis. To better define the interplay between these two critical cellular processes, we determined whether inhibition of macroautophagy could have both pro-apoptotic and anti-apoptotic effects in the same cell. Embryonic fibroblasts from mice with a knock-out of the essential macroautophagy gene atg5 were treated with activators of the extrinsic and intrinsic death pathways. Loss of macroautophagy sensitized these cells to caspase-dependent apoptosis from the death receptor ligands Fas and tumor necrosis factor-alpha (TNF-alpha). Atg5-/- mouse embryonic fibroblasts had increased activation of the mitochondrial death pathway in response to Fas/TNF-alpha in concert with decreased ATP levels. Fas/TNF-alpha treatment failed to up-regulate macroautophagy, and in fact, decreased activity at late time points. In contrast to their sensitization to Fas/TNF-alpha, Atg5-/- cells were resistant to death from menadione and UV light. In the absence of macroautophagy, an up-regulation of chaperone-mediated autophagy induced resistance to these stressors. These results demonstrate that inhibition of macroautophagy can promote or prevent apoptosis in the same cell and that the response is governed by the nature of the death stimulus and compensatory changes in other forms of autophagy. Experimental findings that an inhibition of macroautophagy blocks apoptosis do not prove that autophagy mediates cell death as this effect may result from the protective up-regulation of other autophagic pathways such as chaperone-mediated autophagy.
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Affiliation(s)
- Yongjun Wang
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Rajat Singh
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Ashish C. Massey
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Saul S. Kane
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Susmita Kaushik
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Taneisha Grant
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Youqing Xiang
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Ana Maria Cuervo
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
| | - Mark J. Czaja
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, 10461
- Department of Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, New York, 10461
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Koen YM, Yue W, Galeva NA, Williams TD, Hanzlik RP. Site-specific arylation of rat glutathione s-transferase A1 and A2 by bromobenzene metabolites in vivo. Chem Res Toxicol 2007; 19:1426-34. [PMID: 17112229 PMCID: PMC1661840 DOI: 10.1021/tx060142s] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The hepatotoxicity of bromobenzene (BB) derives from its reactive metabolites (epoxides and quinones), which arylate cellular proteins. Application of proteomic methods to liver proteins from rats treated with a hepatotoxic dose of [14C]-BB has identified more than 40 target proteins, but no adducted peptides have yet been observed. Because such proteins are known to contain bromophenyl- and bromodihydroxyphenyl derivatives of cysteine, histidine, and lysine, the failure to observe modified peptides has been attributed to the low level of total covalent binding and to the "dilution" effect of multiple metabolites reacting at multiple sites on multiple proteins. In this work glutathione S-transferase (GST), a well-known and abundant BB-target protein, was isolated from liver cytosol of rats treated with 14C-BB by use of a glutathione (GSH)-agarose affinity column and further resolved by reverse-phase high-performance liquid chromatography (HPLC) into subunits M1, M2, A1, A2 and A3. The subunits were identified by a combination of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), whole-molecule mass spectrometry, and peptide mass mapping and found to contain radioactivity corresponding to 0.01-0.05 adduct per molecule of protein. Examination of tryptic digests of these subunits by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) and electrospray ionization mass spectrometry (ESI-MS) failed to reveal any apparent adducted peptides despite observed sequence coverages up to 87%. However, use of HPLC-linear ion-trap quadrupole Fourier transform mass spectrometry (LTQ-FTMS) to search for predicted modified tryptic peptides revealed peaks corresponding, with a high degree of mass accuracy, to a bromobenzoquinone adduct of peptide 89-119 in both GSTA1 and A2. The identity of these adducts and their location at Cys-111 was confirmed by tandem mass spectrometry (MS-MS). No evidence for the presence of any putative BB-adducts in GST M1, M2, or A3 was obtained. This work highlights the challenges involved in the unambiguous identification of reactive metabolite adducts formed in vivo.
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Affiliation(s)
- Yakov M Koen
- Department of Medicinal Chemistry and Mass Spectrometry Laboratory, University of Kansas, Lawrence, Kansas 66045, USA
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