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Impaired mitophagy triggers NLRP3 inflammasome activation during the progression from nonalcoholic fatty liver to nonalcoholic steatohepatitis. J Transl Med 2019; 99:749-763. [PMID: 30700851 DOI: 10.1038/s41374-018-0177-6] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 10/26/2018] [Accepted: 11/19/2018] [Indexed: 02/06/2023] Open
Abstract
Activation of inflammation is an important mechanism in the development of nonalcoholic steatohepatitis (NASH). This study aims to delineate how mitophagy affects NLRP3 inflammasome activation in hepatic lipotoxicity. Mice were fed a high fat/calorie diet (HFCD) for 24 weeks. Primary rat hepatocytes were treated with palmitic acid (PA) for various periods of time. Mitophagy was measured by protein levels of LC3II and P62. NLRP3, caspase-1, interleukin (IL)-18, and IL-1β at mRNA and protein levels were used as indicators of inflammasome activation. Along with steatotic progression in HFCD-fed mice, ratio of LC3II/β-actin was decreased concurrently with increased levels of liver P62, NLRP3, caspase-1, IL-1β, IL-18, and serum IL-1β levels in late-stage NASH. PA treatment resulted in mitochondrial oxidative stress and initiated mitophagy in primary hepatocytes. The addition of cyclosporine A did not change LC3II/Τοmm20 ratios; but P62 levels were increased after an extended duration of PA exposure, indicating a defect in autophagic activity. Along with impaired mitophagy, mRNA and protein levels of NLRP3, caspase-1, IL-18 and IL-1β were upregulated by PA treatment. Pretreatment with MCC950, N-acetyl cysteine or acetyl-L-carnitine reversed inflammasome activation and a pyroptotic cascade. Additionally, mitophagic flux was partially recovered as indicated by increases in LC3II/Tomm20 ratio, parkin, and PINK1 expression, and decreased P62 expression. The findings suggest that impaired mitophagy triggers hepatic NLRP3 inflammasome activation in a murine NASH model and primary hepatocytes. The new insights into inflammasome activation through mitophagy advance our understanding of how fatty acids elicit lipotoxicity through oxidant stress and autophagy in mitochondria.
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Lee J, Choi B, No DY, Lee G, Lee SR, Oh H, Lee SH. A 3D alcoholic liver disease model on a chip. Integr Biol (Camb) 2016; 8:302-8. [PMID: 26857817 DOI: 10.1039/c5ib00298b] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alcohol is one of the main causes of liver diseases, and the development of alcoholic liver disease (ALD) treatment methods has been one of the hottest issues. For this purpose, development of in vitro models mimicking the in vivo physiology is one of the critical requirements, and they help to determine the disease mechanisms and to discover the treatment method. Herein, a three-dimensional (3D) ALD model was developed and its superior features in mimicking the in vivo condition were demonstrated. A spheroid-based microfluidic chip was employed for the development of the 3D in vitro model of ALD progression. We co-cultured rat primary hepatocytes and hepatic stellate cells (HSCs) in a fluidic chip to investigate the role of HSCs in the recovery of liver with ALD. An interstitial level of flow derived by an osmotic pump was applied to the chip to provide in vivo mimicking of fluid activity. Using this in vitro tool, we were able to observe structural changes and decreased hepatic functions with the increase in ethanol concentration. The recovery process of liver injured by alcohol was observed by providing fresh culture medium to the damaged 3D liver tissue for few days. A reversibly- and irreversibly-injured ALD model was established. The proposed model can not only be used for the research of alcoholic disease mechanism, but also has the potential for use in studies of hepatotoxicity and drug screening applications.
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Affiliation(s)
- JaeSeo Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713, Republic of Korea
| | - BongHwan Choi
- School of Biomedical Engineering, College of Health Science, Korea University, Seoul 136-713, Republic of Korea
| | - Da Yoon No
- Department of Bioengineering, School of Engineering and Medicine, Stanford University, 318 Campus Drive, Stanford, CA 94305, USA
| | - GeonHui Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713, Republic of Korea
| | - Seung-Ri Lee
- Department of Biopharmaceutical Sciences College of Pharmacy University of Illinois at Chicago, USA
| | - HyunJik Oh
- Department of Biomedical Engineering, College of Health Science, Korea University, Seoul 136-713, Republic of Korea. and MicroFIT R&BD Institute, Dunchon-daero 457beon-gil, Jungwon-gu, Gyeonggi-do 462-806, Republic of Korea
| | - Sang-Hoon Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 136-713, Republic of Korea and Department of Biomedical Engineering, College of Health Science, Korea University, Seoul 136-713, Republic of Korea.
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Kaiser JP, Guo L, Beier JI, Zhang J, Bhatnagar A, Arteel GE. PKCε contributes to chronic ethanol-induced steatosis in mice but not inflammation and necrosis. Alcohol Clin Exp Res 2014; 38:801-9. [PMID: 24483773 PMCID: PMC4157371 DOI: 10.1111/acer.12324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 09/24/2013] [Indexed: 12/21/2022]
Abstract
BACKGROUND Protein kinase C epsilon (PKCε) has been shown to play a role in experimental steatosis by acute alcohol. The "two-hit" hypothesis implies that preventing steatosis should blunt more advanced liver damage (e.g., inflammation and necrosis). However, the role of PKCε in these pathologies is not yet known. The goal of this current work was to address this question in a model of chronic alcohol exposure using antisense oligonucleotides (ASO) against PKCε. METHODS Accordingly, PKCε ASO- and saline-treated mice were fed high-fat control or ethanol (EtOH)-containing enteral diets for 4 weeks. RESULTS Chronic EtOH exposure significantly elevated hepatic lipid pools as well as activated PKCε. The PKCε ASO partially blunted the increases in hepatic lipids caused by EtOH. Administration of PKCε ASO also completely prevented the increase in the expression of fatty acid synthase, and tumor necrosis factor α caused by EtOH. Despite these protective effects, the PKCε ASO was unable to prevent the increases in inflammation and necrosis caused by chronic EtOH. These latter results correlated with an inability of the PKCε ASO to blunt the up-regulation of plasminogen activator inhibitor-1 (PAI-1) and the accumulation of fibrin. Importantly, PAI-1 has been previously shown to more robustly mediate inflammation and necrosis (vs. steatosis) after chronic EtOH exposure. CONCLUSIONS This study identifies a novel potential mechanism where EtOH, independent of steatosis, can contribute to liver damage. These results also suggest that PAI-1 and fibrin accumulation may be at the center of this PKCε-independent pathway.
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Affiliation(s)
- J. Phillip Kaiser
- Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
- University of Louisville Alcohol Research Center, Louisville, KY 40292, USA
| | - Luping Guo
- Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
- University of Louisville Alcohol Research Center, Louisville, KY 40292, USA
| | - Juliane I. Beier
- Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
- University of Louisville Alcohol Research Center, Louisville, KY 40292, USA
| | - Jun Zhang
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, USA
| | - Aruni Bhatnagar
- Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
- Department of Medicine, Division of Cardiology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
| | - Gavin E. Arteel
- Department of Pharmacology and Toxicology, University of Louisville Health Sciences Center, Louisville, KY 40292, USA
- University of Louisville Alcohol Research Center, Louisville, KY 40292, USA
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SOD mimetic improves the function, growth, and survival of small-size liver grafts after transplantation in rats. Transplantation 2012; 94:687-94. [PMID: 22955229 DOI: 10.1097/tp.0b013e3182633478] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Small-for-size syndrome (SFSS) may occur when graft volume is less than 45% of the standard liver volume, and it manifests as retarded growth and failure of the grafts and more mortality. However, its pathogenesis is poorly understood, and few effective interventions have been attempted. AIMS The present study aimed to delineate the critical role of oxidant stress in SFSS and protective effects of a superoxide dismutase mimetic, Mn(III)tetrakis(4-benzoic acid)porphyrin chloride (MnTBAP), on graft function, growth, and survival in the recipient rats. METHODS Small size graft liver transplantation (SSGLT) was performed to determine the survival, graft injury, and growth. MnTBAP was administered in SSGLT recipients (SSGLT+MnTBAP). RESULTS Serum alanine aminotransferase levels were sustained higher in SSGLT recipients, which were correlated with an increased apoptotic cell count and hepatocellular necrosis in liver sections. Malondialdehyde content, gene expression of tumor necrosis factor α and interleukin 1β, and DNA binding activity of nuclear factor-κB in the grafts were increased significantly in SSGLT recipients compared with sham-operated controls. Both phosphorylated p38 mitogen-activated protein kinase and nuclear c-Jun were increased in SSGLT. All these changes were strikingly reversed by the administration of MnTBAP, with an increase in serum superoxide dismutase activity. Moreover, in situ bromodeoxyuridine incorporation demonstrated that graft regeneration was much more profound in the SSGLT+MnTBAP group than in the SSGLT group. Finally, the survival of recipients with MnTBAP treatments was significantly improved. CONCLUSIONS Enhanced oxidant stress with activation of the p38/c-Jun/nuclear factor-κB signaling pathway contributes to SFSS-associated graft failure, retarded graft growth, and poor survival. MnTBAP effectively reversed the pathologic changes in SFSS-associated graft failure.
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Pereira C, Coutinho I, Soares J, Bessa C, Leão M, Saraiva L. New insights into cancer-related proteins provided by the yeast model. FEBS J 2012; 279:697-712. [PMID: 22239976 DOI: 10.1111/j.1742-4658.2012.08477.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cancer is a devastating disease with a profound impact on society. In recent years, yeast has provided a valuable contribution with respect to uncovering the molecular mechanisms underlying this disease, allowing the identification of new targets and novel therapeutic opportunities. Indeed, several attributes make yeast an ideal model system for the study of human diseases. It combines a high level of conservation between its cellular processes and those of mammalian cells, with advantages such as a short generation time, ease of genetic manipulation and a wealth of experimental tools for genome- and proteome-wide analyses. Additionally, the heterologous expression of disease-causing proteins in yeast has been successfully used to gain an understanding of the functions of these proteins and also to provide clues about the mechanisms of disease progression. Yeast research performed in recent years has demonstrated the tremendous potential of this model system, especially with the validation of findings obtained with yeast in more physiologically relevant models. The present review covers the major aspects of the most recent developments in the yeast research area with respect to cancer. It summarizes our current knowledge on yeast as a cellular model for investigating the molecular mechanisms of action of the major cancer-related proteins that, even without yeast orthologues, still recapitulate in yeast some of the key aspects of this cellular pathology. Moreover, the most recent contributions of yeast genetics and high-throughput screening technologies that aim to identify some of the potential causes underpinning this disorder, as well as discover new therapeutic agents, are discussed.
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Affiliation(s)
- Clara Pereira
- REQUIMTE, Department of Biological Sciences, Laboratory of Microbiology, University of Porto, Portugal
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Schie IW, Wu J, Zern M, Rutledge JC, Huser T. Label-free imaging and analysis of the effects of lipolysis products on primary hepatocytes. JOURNAL OF BIOPHOTONICS 2011; 4:425-34. [PMID: 20878906 PMCID: PMC3696389 DOI: 10.1002/jbio.201000086] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/06/2010] [Accepted: 09/06/2010] [Indexed: 05/07/2023]
Abstract
The increased accumulation of intracellular lipid droplets within hepatocytes is a pathologic hallmark of liver injury of various etiologies, especially non-alcoholic steatohepatitis (NASH). The dynamics, subcellular origin, and chemical composition of lipid droplets under various pathophysiologic conditions, however, remain poorly understood. We used coherent Raman microscopy and spontaneous Raman spectroscopy to monitor and analyze the formation of lipid droplets in living primary rat hepatocytes exposed to triglyceride-rich lipoprotein (TGRL) lipolysis products. After exposure to the complex fatty acid mixture released during the lipolysis process for 30 minutes, new lipid droplets rapidly appeared within hepatocytes and increased in size and number over the total observation period of 205 minutes. Raman spectroscopic analysis of individual intracellular lipid droplets before and after exposure to lipolysis products reveals that the major components of these droplets are esterified unsaturated fatty acids. We find that the fatty acid unsaturation ratio increases with droplet size. Control experiments with defined fatty acid mixtures reveal the complexity of the cellular response to assault by combinations of lipids.
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Affiliation(s)
- Iwan W. Schie
- NSF Center for Biophotonics Science and Technology, University of California, Davis, Sacramento, CA 95817, USA
| | - Jian Wu
- Division of Gastroenterology & Hepatology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Mark Zern
- Division of Gastroenterology & Hepatology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - John C. Rutledge
- Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California, Davis, Sacramento, CA 95817, USA
| | - Thomas Huser
- NSF Center for Biophotonics Science and Technology, University of California, Davis, Sacramento, CA 95817, USA
- Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California, Davis, Sacramento, CA 95817, USA
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Zhou P, Lessa N, Estrada DC, Severrson EB, Lingala S, Zern MA, Nolta JA, Wu J. Decellularized liver matrix as a carrier for the transplantation of human fetal and primary hepatocytes in mice. Liver Transpl 2011; 17:418-27. [PMID: 21445925 PMCID: PMC3079538 DOI: 10.1002/lt.22270] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The transplantation of primary hepatocytes has been shown to augment the function of damaged livers and to bridge patients to liver transplantation. However, primary hepatocytes often have low levels of engraftment and survive for only a short time after transplantation. To explore the potential benefits of using decellularized liver matrix (DLM) as a carrier for hepatocyte transplantation, DLM from whole mouse livers was generated. Human fetal hepatocytes immortalized by telomerase reconstitution (FH-hTERTs) or primary human hepatocytes were infused into the DLM, which was then implanted into the omenta of immunodeficient nonobese diabetic/severe combined immunodeficient/interleukin-2 receptor γ-deficient mice or nonobese diabetic/severe combined immunodeficient/mucopolysaccharidosis type VII mice. The removal of endogenous cellular components and the preservation of the extracellular matrix proteins and vasculature were demonstrated in the resulting DLM. Bioluminescent imaging revealed that FH-hTERTs transduced with a lentiviral vector expressing firefly luciferase survived in the DLM for 8 weeks after peritoneal implantation, whereas the luciferase signal from FH-hTERTs rapidly declined in control mice 3 to 4 weeks after transplantation via splenic injection or omental implantation after Matrigel encapsulation. Furthermore, primary human hepatocytes that were reconstituted in the DLM not only survived 6 weeks after transplantation but also maintained their function, as demonstrated by messenger RNA levels of albumin and cytochrome P450 (CYP) subtypes (CYP3A4, CYP2C9, and CYP1A1) similar to the levels in freshly isolated human primary hepatocytes (hPHs). In contrast, when hPHs were transplanted into mice via splenic injection, they failed to express CYP3A4, although they expressed albumin. In conclusion, DLM provides an excellent environment for long-term survival and maintenance of the hepatocyte phenotype after transplantation.
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Affiliation(s)
- Ping Zhou
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Nataly Lessa
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Daniel C. Estrada
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Ella B. Severrson
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Shilpa Lingala
- Transplant Research Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Mark A. Zern
- Transplant Research Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Jan A. Nolta
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
| | - Jian Wu
- Stem Cell Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817, Transplant Research Program, Department of Internal Medicine, University of California, Davis Medical Center, Sacramento, CA 95817
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Aroor AR, James TT, Jackson DE, Shukla SD. Differential changes in MAP kinases, histone modifications, and liver injury in rats acutely treated with ethanol. Alcohol Clin Exp Res 2010; 34:1543-51. [PMID: 20586759 DOI: 10.1111/j.1530-0277.2010.01239.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Acute ethanol is known to affect cells and organs but the underlying molecular mechanisms are poorly explored. Recent developments highlight the potential importance of mitogen-activated protein kinases, MAPKs (i.e., ERK1/2, p38, and JNK1/2) signaling, and histone modifications (i.e., acetylation, methylation, and phosphorylation) in the actions of ethanol in hepatocytes. We have therefore investigated significance of these molecular steps in vivo using a model in which rats were acutely administered ethanol intraperitoneally (IP). METHODS Ethanol was administered IP (3.5 gm/kg body weight) to 12-week-old male Sprague-Dawley rats. Liver was subsequently removed at 1 and 4 hours. Serum was used for alcohol and ALT assays. At the time of the removal of liver, small portions of each liver were formalin-fixed and stained with hematoxylin and eosin (H&E) and used for light microscopy. Western blot analysis was carried out with specific primary antibodies for various parameters. RESULTS There were clear differences at 1 and 4 hours in blood ethanol, ALT, steatosis, and cleaved caspase 3. Apoptosis at 1 hour was followed by necrosis at 4 hours. Acute alcohol elicited a marked increase in the phosphorylation of ERK1/2 and moderate increases in the phosphorylation of p38 MAPK and JNK. Temporally different phosphorylation of histone H3 at ser-10 and ser-28 occurred and acetylation of histone H3 at lys 9 increased progressively. CONCLUSIONS There were distinct differences in the behavior of the activation of the 3 MAP kinases and histone modifications after acute short exposure of liver to ethanol in vivo. Although all 3 MAPKs were rapidly activated at 1 hour, the necrosis, occurring at 4 hours, correlated to sustained activation of ERK1/2. Transient activation of p38 is associated with rapid phosphorylation of histone H3, whereas prolonged activation of ERK1/2 is correlated to persistent histone H3 acetylation.
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Affiliation(s)
- Annayya R Aroor
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri, USA
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Liangpunsakul S, Sozio MS, Shin E, Zhao Z, Xu Y, Ross RA, Zeng Y, Crabb DW. Inhibitory effect of ethanol on AMPK phosphorylation is mediated in part through elevated ceramide levels. Am J Physiol Gastrointest Liver Physiol 2010; 298:G1004-12. [PMID: 20224005 PMCID: PMC3774334 DOI: 10.1152/ajpgi.00482.2009] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ethanol treatment of cultured hepatoma cells and of mice inhibited the activity of AMP-activated protein kinase (AMPK). This study shows that the inhibitory effect of ethanol on AMPK phosphorylation is exerted through the inhibition of the phosphorylation of upstream kinases and the activation of protein phosphatase 2A (PP2A).Inhibition of AMPK phosphorylation by palmitate was attributed to ceramide-dependent PP2A activation. We hypothesized that the inhibitory effect of ethanol on AMPK phosphorylation was mediated partly through the generation of ceramide. The effect of ethanol and inhibitors of ceramide synthesis on AMPK phosphorylation, ceramide levels, and PP2A activity were assessed in rat hepatoma cells (H4IIEC3). The effect of ethanol on hepatic ceramide levels was also studied in C57BL/6J mice fed the Lieber-DeCarli diet. In H4IIEC3 cells, ceramide reduced AMPK phosphorylation when they were treated for between 4 and 12 h. The basal level of AMPK phosphorylation in hepatoma cells was increased with the treatment of ceramide synthase inhibitor, fumonisin B1. Ethanol treatment significantly increased cellular ceramide content and PP2A activity by approximately 18-23%, when the cells were treated with ethanol for between 4 and 12 h. These changes in intracellular ceramide concentrations and PP2A activity correlated with the time course over which ethanol inhibited AMPK phosphorylation. The activation of PP2A and inhibition of AMPK phosphorylation caused by ethanol was attenuated by fumonisin B1 and imipramine, an acid sphingomyelinase (SMase) inhibitor. There was a significant increase in the levels of ceramide and acid SMase mRNA in the livers of ethanol-fed mice compared with controls. We concluded that the effect of ethanol on AMPK appears to be mediated in part through increased cellular levels of ceramide and activation of PP2A.
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Affiliation(s)
- Suthat Liangpunsakul
- Departments of 1Medicine, Indiana University School of Medicine, Indianapolis, Indiana.
| | - Margaret S. Sozio
- Departments of 1Medicine, Division of Gastroenterology and Hepatology, Roudebush Veterans Administration Medical Center, and
| | - Eric Shin
- Departments of 1Medicine, Division of Gastroenterology and Hepatology, Roudebush Veterans Administration Medical Center, and
| | - Zhenwen Zhao
- 2Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yan Xu
- 2Obstetrics and Gynecology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Ruth A. Ross
- Departments of 1Medicine, Division of Gastroenterology and Hepatology, Roudebush Veterans Administration Medical Center, and
| | - Yan Zeng
- Departments of 1Medicine, Division of Gastroenterology and Hepatology, Roudebush Veterans Administration Medical Center, and
| | - David W. Crabb
- Departments of 1Medicine, Division of Gastroenterology and Hepatology, Roudebush Veterans Administration Medical Center, and
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Cultivating hepatocytes on printed arrays of HGF and BMP7 to characterize protective effects of these growth factors during in vitro alcohol injury. Biomaterials 2010; 31:5936-44. [PMID: 20488537 DOI: 10.1016/j.biomaterials.2010.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 04/05/2010] [Indexed: 02/06/2023]
Abstract
The goal of the present study was to investigate hepato-protective effects of growth factor (GF) arrays during alcohol injury. Hepatocyte growth factor (HGF) and bone morphogenetic protein (BMP)7 were mixed with collagen (I) and robotically printed onto standard glass slides to create arrays of 500 microm diameter spots. Primary rat hepatocytes were seeded on top of the arrays forming clusters corresponding in size to the underlying protein spots. Cell arrays were then injured in culture by exposure to 100 mm ethanol for 48 h. Hepatocytes residing on GF spots were found to have less apoptosis then cells cultured on collagen-only spots. Least apoptosis (0.3% as estimated by TUNEL assay) was observed on HGF/BMP7/collagen spots whereas most apoptosis (17.3%) was seen on collagen-only arrays. Interestingly, the extent of alcohol-induced apoptosis in hepatocytes varied based on the concentration of printed GF. In addition to preventing apoptosis, printed GFs contributed to maintenance of epithelial phenotype during alcohol injury as evidenced by higher levels of E-cadherin expression in HGF-protected hepatocytes. Importantly, GF microarrays could be used to investigate heterotypic interactions in the context of liver injury. To highlight this, stellate cells - nonparenchymal liver cells involved in fibrosis - were added to hepatocytes residing on arrays of either HGF/collagen or collagen-only spots. Exposure of these cocultures to ethanol followed by RT-PCR analysis revealed that stellate cells residing alongside HGF-protected hepatocytes were significantly less activated (less fibrotic) compared to controls. Overall, our results demonstrate that GF microarray format can be used to screen anti-fibrotic and anti-apoptotic effects of growth factors as well as to investigate how signals delivered to a specific cell type modulate heterotypic cellular interactions.
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Reichel M, Greiner E, Richter-Schmidinger T, Yedibela O, Tripal P, Jacobi A, Bleich S, Gulbins E, Kornhuber J. Increased acid sphingomyelinase activity in peripheral blood cells of acutely intoxicated patients with alcohol dependence. Alcohol Clin Exp Res 2009; 34:46-50. [PMID: 19860808 DOI: 10.1111/j.1530-0277.2009.01064.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Acid sphingomyelinase (ASM; EC 3.1.4.12) hydrolyses membrane sphingomyelin into the bioactive lipid ceramide and is thus involved in different cellular processes such as differentiation, immunity, or cell death. Activation of ASM has been reported in particular in conjunction with the cellular stress response to several external stimuli, and increased ASM activity was observed in a variety of human diseases. Ethanol-induced activation of ASM has been observed in different cell culture systems, thus raising the question about the effect of alcohol intoxication in human subjects on ASM activity in vivo. METHODS We determined ASM activity in peripheral blood mononucleated cells of 27 patients suffering from alcohol dependence. Patients were classified according to their blood alcohol concentration at admission, and ASM activity was determined repeatedly from all patients during alcohol withdrawal. RESULTS Acutely intoxicated patients displayed significantly higher ASM activity than patients in early abstinence (Mann-Whitney U test: Z = - 2.6, p = 0.009). ASM activity declined in acutely intoxicated patients to normal values with the transition from the intoxicated state to early abstinence (Wilcoxon test: Z = -2.7, p = 0.007). At the end of withdrawal, ASM activity was significantly increased again compared to the early phase of abstinence in both patient groups (Wilcoxon test: Z = -2.691, p = 0.007 and Z = -2.275, p = 0.023, respectively). CONCLUSIONS Alcohol-induced activation of ASM occurs in human subjects and might be responsible for deleterious effects of ethanol intoxication. Chronic alcohol abuse may induce deregulation of sphingomyelin metabolism in general, and this impairment may cause side effects during withdrawal from alcohol.
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Affiliation(s)
- Martin Reichel
- Department of Psychiatry and Psychotherapy, University of Erlangen, Erlangen, Germany.
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Coutinho I, Pereira G, Leão M, Gonçalves J, Côrte-Real M, Saraiva L. Differential regulation of p53 function by protein kinase C isoforms revealed by a yeast cell system. FEBS Lett 2009; 583:3582-8. [DOI: 10.1016/j.febslet.2009.10.030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 10/09/2009] [Accepted: 10/13/2009] [Indexed: 12/27/2022]
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Coutinho I, Pereira G, Simões MF, Côrte-Real M, Gonçalves J, Saraiva L. Selective activation of protein kinase C-delta and -epsilon by 6,11,12,14-tetrahydroxy-abieta-5,8,11,13-tetraene-7-one (coleon U). Biochem Pharmacol 2009; 78:449-59. [PMID: 19413996 DOI: 10.1016/j.bcp.2009.04.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 04/26/2009] [Accepted: 04/27/2009] [Indexed: 10/20/2022]
Abstract
6,11,12,14-tetrahydroxy-abieta-5,8,11,13-tetraene-7-one (coleon U) is a diterpene compound isolated from Plectranthus grandidentatus with an antiproliferative effect on several human cancer cell lines. Herein, we studied the modulatory activity of coleon U on individual isoforms of the three protein kinase C (PKC) subfamilies, classical (cPKC-alpha and -betaI), novel (nPKC-delta and -epsilon) and atypical (aPKC-zeta), using a yeast PKC assay. The results showed that, whereas the PKC activator phorbol-12-myristate-13-acetate (PMA) activated every PKC tested except aPKC, coleon U had no effect on aPKC and cPKCs. Besides, the effect of coleon U on nPKCs was higher than that of PMA. This revealed that coleon U was a potent and selective activator of nPKCs. The isoform-selectivity of coleon U for nPKC-delta and -epsilon was confirmed using an in vitro PKC assay. Most importantly, while PMA activated nPKCs inducing an isoform translocation from the cytosol to the plasma membrane and a G2/M cell cycle arrest, coleon U induced nPKCs translocation to the nucleus and a metacaspase- and mitochondrial-dependent apoptosis. This work therefore reconstitutes in yeast distinct subcellular translocations of a PKC isoform and the subsequent distinct cellular responses reported for mammalian cells. Together, our study identifies a new isoform-selective PKC activator with promising pharmacological applications. Indeed, since coleon U has no effect on cPKCs and aPKC, recognised as anti-apoptotic proteins, and selectively induces an apoptotic pathway dependent on nPKC-delta and -epsilon activation, it represents a promising compound for evaluation as an anti-cancer drug.
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Affiliation(s)
- I Coutinho
- Laboratório de Microbiologia, REQUIMTE/CEQUP, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, 4050-047 Porto, Portugal
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Kim TH, Venugopal SK, Zhu M, Wang SS, Lau D, Lam KS, Clemens DL, Zern MA. A novel small molecule, LAS-0811, inhibits alcohol-induced apoptosis in VL-17A cells. Biochem Biophys Res Commun 2009; 379:876-81. [PMID: 19133235 DOI: 10.1016/j.bbrc.2008.12.133] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 12/20/2008] [Indexed: 01/10/2023]
Abstract
One of the pathways by which alcohol induces hepatocyte apoptosis is via oxidative stress. We screened several chemically-synthesized small molecules and found LAS-0811, which inhibits oxidative stress. In this study, we elucidated its role in inhibiting alcohol-induced apoptosis in hepatocyte-like VL-17A cells. VL-17A cells were pre-incubated with LAS-0811, followed by ethanol incubation. Ethanol-induced reactive oxygen species and apoptosis were significantly inhibited in LAS-0811 pre-treated cells. VL-17A cells were transfected with a reporter (ARE/TK-GFP) plasmid containing green fluorescent protein (GFP) as a reporter gene and the anti-oxidant response element as the promoter. LAS-0811 pre-treatment significantly induced the GFP expression compared to the cells treated with ethanol alone. LAS-0811 induced the activation of nrf2 and enhanced the expression and activity of glutathione peroxidase, one of the downstream targets of nrf2. The results indicate that LAS-0811 protects VL-17A cells against ethanol-induced oxidative stress and apoptosis at least in part via nrf2 activation.
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Affiliation(s)
- Tae-Hun Kim
- Department of Internal Medicine, Transplant Research Program, University of California Davis Medical Center, 4635 2nd Ave. Research Building I, Room 1001, Sacramento, CA 95817, USA
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Choi EY, Hwang HJ, Kim IH, Nam TJ. Protective effects of a polysaccharide from Hizikia fusiformis against ethanol toxicity in rats. Food Chem Toxicol 2009; 47:134-9. [PMID: 19026708 DOI: 10.1016/j.fct.2008.10.026] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 10/14/2008] [Accepted: 10/21/2008] [Indexed: 01/25/2023]
Abstract
Hizikia fusiformis is an edible brown alga that is widely consumed in Korea, Japan, and China and possesses a number of potentially beneficial compounds, including antioxidants and anticoagulants. No reports have investigated potential H. fusiformis protectants against ethanol-induced peptic injury. We extracted a polysaccharide from H. fusiformis (Hf-PS-1) that exhibited protective effects against ethanol-induced peptic injury and related mechanisms in rats. Experimental animals were divided into three groups: control, ethanol-only, and ethanol+Hf-PS-1. The ethanol-only group exhibited decreased levels of total glutathione (GSH) and increased levels of jun N-terminal kinase (JNK) phosphorylation relative to the control group, whereas levels were significantly increased and decreased, respectively, in the ethanol+Hf-PS-1 group. The ethanol-only group also exhibited increased levels of extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation relative to the control group; these levels were not significantly different in the ethanol+Hf-PS-1 group. Hf-PS-1 appeared to reduce ethanol-induced gastric injury. Therefore, we suggest that Hf-PS-1 could protect against ethanol-induced peptic ulcers primarily through a mechanism associated with the inhibition of JNK activation.
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Affiliation(s)
- Eun-Young Choi
- Faculty of Food Science and Biotechnology, Pukyong National University, 599-1, Daeyeon 3-Dong, Nam-gu, Busan 608-737, Republic of Korea [corrected]
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