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Janilkarn-Urena I, Idrissova A, Zhang M, VanDreal M, Sanghavi N, Skinner SG, Cheng S, Zhang Z, Watanabe J, Asatryan L, Cadenas E, Davies DL. Dihydromyricetin supplementation improves ethanol-induced lipid accumulation and inflammation. Front Nutr 2023; 10:1201007. [PMID: 37680900 PMCID: PMC10481966 DOI: 10.3389/fnut.2023.1201007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/01/2023] [Indexed: 09/09/2023] Open
Abstract
Introduction Excessive alcohol consumption leads to a myriad of detrimental health effects, including alcohol-associated liver disease (ALD). Unfortunately, no available treatments exist to combat the progression of ALD beyond corticosteroid administration and/or liver transplants. Dihydromyricetin (DHM) is a bioactive polyphenol and flavonoid that has traditionally been used in Chinese herbal medicine for its robust antioxidant and anti-inflammatory properties. It is derived from many plants, including Hovenia dulcis and is found as the active ingredient in a variety of popular hangover remedies. Investigations utilizing DHM have demonstrated its ability to alleviate ethanol-induced disruptions in mitochondrial and lipid metabolism, while demonstrating hepatoprotective activity. Methods Female c57BL/6J mice (n = 12/group) were treated using the Lieber DeCarli forced-drinking and ethanol (EtOH) containing liquid diet, for 5 weeks. Mice were randomly divided into three groups: (1) No-EtOH, (2) EtOH [5% (v/v)], and (3) EtOH [5% (v/v)] + DHM (6 mg/mL). Mice were exposed to ethanol for 2 weeks to ensure the development of ALD pathology prior to receiving dihydromyricetin supplementation. Statistical analysis included one-way ANOVA along with Bonferroni multiple comparison tests, where p ≤ 0.05 was considered statistically significant. Results Dihydromyricetin administration significantly improved aminotransferase levels (AST/ALT) and reduced levels of circulating lipids including LDL/VLDL, total cholesterol (free cholesterol), and triglycerides. DHM demonstrated enhanced lipid clearance by way of increased lipophagy activity, shown as the increased interaction and colocalization of p62/SQSTM-1, LC3B, and PLIN-1 proteins. DHM-fed mice had increased hepatocyte-to-hepatocyte lipid droplet (LD) heterogeneity, suggesting increased neutralization and sequestration of free lipids into LDs. DHM administration significantly reduced prominent pro-inflammatory cytokines commonly associated with ALD pathology such as TNF-α, IL-6, and IL-17. Discussion Dihydromyricetin is commercially available as a dietary supplement. The results of this proof-of-concept study demonstrate its potential utility and functionality as a cost-effective and safe candidate to combat inflammation and the progression of ALD pathology.
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Affiliation(s)
- Isis Janilkarn-Urena
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Alina Idrissova
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Mindy Zhang
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Masha VanDreal
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Neysa Sanghavi
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Samantha G. Skinner
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Sydney Cheng
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Zeyu Zhang
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
- Translational Research Lab, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, United States
| | - Junji Watanabe
- Translational Research Lab, USC Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA, United States
- Department of Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Liana Asatryan
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Enrique Cadenas
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
| | - Daryl L. Davies
- Titus Family Department of Clinical Pharmacy, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles, CA, United States
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Harris PS, McGinnis CD, Michel CR, Marentette JO, Reisdorph R, Roede JR, Fritz KS. Click chemistry-based thiol redox proteomics reveals significant cysteine reduction induced by chronic ethanol consumption. Redox Biol 2023; 64:102792. [PMID: 37390786 PMCID: PMC10331594 DOI: 10.1016/j.redox.2023.102792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 06/09/2023] [Accepted: 06/18/2023] [Indexed: 07/02/2023] Open
Abstract
In the U.S., alcohol-associated liver disease (ALD) impacts millions of people and is a major healthcare burden. While the pathology of ALD is unmistakable, the molecular mechanisms underlying ethanol hepatotoxicity are not fully understood. Hepatic ethanol metabolism is intimately linked with alterations in extracellular and intracellular metabolic processes, specifically oxidation/reduction reactions. The xenobiotic detoxification of ethanol leads to significant disruptions in glycolysis, β-oxidation, and the TCA cycle, as well as oxidative stress. Perturbation of these regulatory networks impacts the redox status of critical regulatory protein thiols throughout the cell. Integrating these key concepts, our goal was to apply a cutting-edge approach toward understanding mechanisms of ethanol metabolism in disrupting hepatic thiol redox signaling. Utilizing a chronic murine model of ALD, we applied a cysteine targeted click chemistry enrichment coupled with quantitative nano HPLC-MS/MS to assess the thiol redox proteome. Our strategy reveals that ethanol metabolism largely reduces the cysteine proteome, with 593 cysteine residues significantly reduced and 8 significantly oxidized cysteines. Ingenuity Pathway Analysis demonstrates that ethanol metabolism reduces specific cysteines throughout ethanol metabolism (Adh1, Cat, Aldh2), antioxidant pathways (Prx1, Mgst1, Gsr), as well as many other biochemical pathways. Interestingly, a sequence motif analysis of reduced cysteines showed a correlation for hydrophilic, charged amino acids lysine or glutamic acid nearby. Further research is needed to determine how a reduced cysteine proteome impacts individual protein activity across these protein targets and pathways. Additionally, understanding how a complex array of cysteine-targeted post-translational modifications (e.g., S-NO, S-GSH, S-OH) are integrated to regulate redox signaling and control throughout the cell is key to the development of redox-centric therapeutic agents targeted to ameliorate the progression of ALD.
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Affiliation(s)
- Peter S Harris
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Courtney D McGinnis
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Cole R Michel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - John O Marentette
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Richard Reisdorph
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - James R Roede
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Kristofer S Fritz
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Liu XH, Pang X, Jin L, Pu DY, Wang ZJ, Zhang YG. Exposure to acute waterborne cadmium caused severe damage on lipid metabolism of freshwater fish, revealed by nuclear lipid droplet deposition in hepatocytes of rare minnow. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2023; 257:106433. [PMID: 36841070 DOI: 10.1016/j.aquatox.2023.106433] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Revised: 02/02/2023] [Accepted: 02/16/2023] [Indexed: 05/12/2023]
Abstract
Cadmium (Cd) is a widely distributed aquatic toxic heavy metal with the potential to disrupt fish metabolism; however, more research is needed to clarify the underlying mechanisms. In the present study, rare minnows (Gobiocypris rarus) were used to detect the effects of cadmium on freshwater fish lipid metabolism and its underlying mechanism by histopathological observation, measurement of serum and liver biochemical indexes, and analysis of gene expression in terms of lipid oxidation, synthesis and transport. Here, severe damage, such as cytoplasmic lipid droplet (LD) accumulation, ectopic deposition of LDs, and the appearance of nuclear LDs (nLDs), was detected after exposure to 2.0 mg/L or higher concentrations (2.5 and 2.8 mg/L CdCl2) for 96 h. Other damage included abnormal increases in rough endoplasmic reticulum (RER) lamellae in a fingerprint or concentric circle pattern and necrosis of hepatocytes, and which was observed in the livers of fish exposed to 2.0 mg/L CdCl2.. Both hepatic and serum lipids, such as triglycerides and total cholesterol, were significantly increased after exposure to 2.0 mg/L CdCl2, as was serum lipase (LPS). Hepatic lipase and lipoprotein lipase remained unchanged, in accordance with the unchanged hepatic mRNA transcripts of PPARɑ. Furthermore, the mRNA transcripts of both SCD and SQLE were significantly decreased. Moreover, hepatic and serum low-density and high-density lipoprotein cholesterol showed significant changes, which were accompanied by a significant increase and decrease in hepatic APOAI and APOB100 mRNA levels, respectively. All the results indicate the presence of severe damage to hepatic lipid metabolism and that disrupted lipid transport may play a key role in the accumulation of hepatic LDs. In addition, the hepatic nLDs of nonmammalian vertebrates and their location across the nuclear envelope are intriguing, suggesting that large-size nLDs are a common marker for severe liver damage.
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Affiliation(s)
- Xiao-Hong Liu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Xu Pang
- College of Fisheries, Institute of Three Gorges Ecological Fisheries of Chongqing, Southwest University, Chongqing 400715, China
| | - Li Jin
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - De-Yong Pu
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China
| | - Zhi-Jian Wang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China.
| | - Yao-Guang Zhang
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Key Laboratory of Aquatic Science of Chongqing, Southwest University School of Life Sciences, Chongqing 400715, China.
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Mak KM, Wu C, Cheng CP. Lipid droplets, the Holy Grail of hepatic stellate cells: In health and hepatic fibrosis. Anat Rec (Hoboken) 2022; 306:983-1010. [PMID: 36516055 DOI: 10.1002/ar.25138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 11/07/2022] [Accepted: 11/29/2022] [Indexed: 12/15/2022]
Abstract
Lipid droplets (LDs) are distinct morphological markers of hepatic stellate cells (HSCs). They are composed of a core of predominantly retinyl esters and triacylglycerols surrounded by a phospholipid layer; the latter harbors perilipins 2, 3, and 5, which help control LD lipolysis. Electron microscopy distinguishes between Types I and II LDs. Type I LDs are surrounded by acid phosphatase-positive lysosomes, which likely digest LDs. LD count and retinoid concentration are modulated by vitamin A intake. Alcohol consumption depletes hepatic retinoids and HSC LDs, with concomitant transformation of HSCs to fibrogenic myofibroblast-like cells. LD loss and accompanying HSC activation occur in HSC cell culture models. Loss of LDs is a consequence of and not a prerequisite for HSC activation. LDs are endowed with enzymes for synthesizing retinyl esters and triacylglycerols as well as neutral lipases and lysosomal acid lipase for breaking down LDs. HSCs have two distinct metabolic LD pools: an "original" pool in quiescent HSCs and a "new" pool emerging in HSC activation; this two-pool model provides a platform for analyzing LD dynamics in HSC activation. Besides lipolysis, LDs are degraded by lipophagy; however, the coordination between and relative contributions of these two pathways to LD removal are unclear. While induction of autophagy accelerates LD loss in quiescent HSCs and promotes HSC activation, blocking autophagy impairs LD degradation and inhibits HSC activation and fibrosis. This article is a critique of five decades of investigations into the morphology, molecular structure, synthesis, and degradation of LDs associated with HSC activation and fibrosis.
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Affiliation(s)
- Ki M Mak
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Catherine Wu
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Christopher P Cheng
- Department of Medical Education and Center for Anatomy and Functional Morphology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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Ferdouse A, Clugston RD. Pathogenesis of Alcohol-Associated Fatty Liver: Lessons From Transgenic Mice. Front Physiol 2022; 13:940974. [PMID: 35864895 PMCID: PMC9294393 DOI: 10.3389/fphys.2022.940974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 06/15/2022] [Indexed: 12/18/2022] Open
Abstract
Alcohol-associated liver disease (ALD) is a major public health issue that significantly contributes to human morbidity and mortality, with no FDA-approved therapeutic intervention available. The health burden of ALD has worsened during the COVID-19 pandemic, which has been associated with a spike in alcohol abuse, and a subsequent increase in hospitalization rates for ALD. A key knowledge gap that underlies the lack of novel therapies for ALD is a need to better understand the pathogenic mechanisms that contribute to ALD initiation, particularly with respect to hepatic lipid accumulation and the development of fatty liver, which is the first step in the ALD spectrum. The goal of this review is to evaluate the existing literature to gain insight into the pathogenesis of alcohol-associated fatty liver, and to synthesize alcohol’s known effects on hepatic lipid metabolism. To achieve this goal, we specifically focus on studies from transgenic mouse models of ALD, allowing for a genetic dissection of alcohol’s effects, and integrate these findings with our current understanding of ALD pathogenesis. Existing studies using transgenic mouse models of ALD have revealed roles for specific genes involved in hepatic lipid metabolic pathways including fatty acid uptake, mitochondrial β-oxidation, de novo lipogenesis, triglyceride metabolism, and lipid droplet formation. In addition to reviewing this literature, we conclude by identifying current gaps in our understanding of how alcohol abuse impairs hepatic lipid metabolism and identify future directions to address these gaps. In summary, transgenic mice provide a powerful tool to understand alcohol’s effect on hepatic lipid metabolism and highlight that alcohol abuse has diverse effects that contribute to the development of alcohol-associated fatty liver disease.
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Li Y, Wei M, Yuan Q, Liu Y, Tian T, Hou L, Zhang J. MyD88 in hepatic stellate cells promotes the development of alcoholic fatty liver via the AKT pathway. J Mol Med (Berl) 2022; 100:1071-1085. [PMID: 35708745 DOI: 10.1007/s00109-022-02196-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 10/18/2022]
Abstract
Myeloid differentiation primary response gene 88 (MyD88), an adaptor protein in the Toll-like receptors (TLRs) signalling pathway, is expressed in various liver cells including hepatocytes, Kupffer cells and hepatic stellate cells (HSCs). And yet, the functional role of MyD88 in HSCs is poorly elucidated in alcoholic fatty liver (AFL). Here, to study the functional role of MyD88 in HSCs and the molecular mechanism related to the development of AFL, chronic-binge ethanol mouse models were established in mice with specific MyD88 knockout in quiescent (MyD88GFAP-KO) and activated HSCs (MyD88SMA-KO), respectively. Our results clearly showed an elevated expression of MyD88 in liver tissues of ethanol treated mouse model which harbours the wild type. Intriguingly, ethanol treatment profoundly inhibited inflammation in both MyD88GFAP-KO and MyD88SMA-KO mice, but the suppression of lipogenesis was only observed in MyD88GFAP-KO mice. Molecularly, our study indicated that MyD88 induced osteopontin (OPN) secretion in HSCs, which consequently resulted in activation of AKT signalling pathway and accumulation of fat in hepatocytes. Additionally, our data also suggested that OPN promoted inflammation by activating p-STAT1. Thus, targeting MyD88 may be a potentially represent a promising strategy for the prevention and treatment of AFL. KEY MESSAGES: The expression of MyD88 in HSCs was significantly increased in ethanol-induced liver tissues of wild-type mice. MyD88 deficiency in quiescent HSCs inhibited inflammation and lipogenesis under the ethanol feeding condition. MyD88 deficiency in activated HSCs only inhibited inflammation under the ethanol feeding condition. MyD88 promoted the OPN secretion of HSCs, which further activated the AKT signalling pathway of hepatocytes and upregulated lipogenic gene expression to promote fat accumulation. OPN also promotes inflammation by activating p-STAT1.
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Affiliation(s)
- Yukun Li
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Miaomiao Wei
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Qi Yuan
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Yu Liu
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Tian Tian
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China
| | - Lingling Hou
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China.
| | - Jinhua Zhang
- The College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing, People's Republic of China.
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Charkoftaki G, Tan WY, Berrios-Carcamo P, Orlicky DJ, Golla JP, Garcia-Milian R, Aalizadeh R, Thomaidis NS, Thompson DC, Vasiliou V. Liver metabolomics identifies bile acid profile changes at early stages of alcoholic liver disease in mice. Chem Biol Interact 2022; 360:109931. [PMID: 35429548 PMCID: PMC9364420 DOI: 10.1016/j.cbi.2022.109931] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/30/2022] [Accepted: 04/03/2022] [Indexed: 12/18/2022]
Abstract
Alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. The liver sustains the earliest and the greatest degree of tissue injury due to chronic alcohol consumption and it has been estimated that alcoholic liver disease (ALD) accounts for almost 50% of all deaths from cirrhosis in the world. In this study, we used a modified Lieber-DeCarli (LD) diet to treat mice with alcohol and simulate chronic alcohol drinking. Using an untargeted metabolomics approach, our aim was to identify the various metabolites and pathways that are altered in the early stages of ALD. Histopathology showed minimal changes in the liver after 6 weeks of alcohol consumption. However, untargeted metabolomics analyses identified 304 metabolic features that were either up- or down-regulated in the livers of ethanol-consuming mice. Pathway analysis revealed significant alcohol-induced alterations, the most significant of which was in the FXR/RXR activation pathway. Targeted metabolomics focusing on bile acid biosynthesis showed elevated taurine-conjugated cholic acid compounds in ethanol-consuming mice. In summary, we showed that the changes in the liver metabolome manifest very early in the development of ALD, and when minimal changes in liver histopathology have occurred. Although alterations in biochemical pathways indicate a complex pathology in the very early stages of alcohol consumption, bile acid changes may serve as biomarkers of the early onset of ALD.
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Affiliation(s)
- Georgia Charkoftaki
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Wan Ying Tan
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Pablo Berrios-Carcamo
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Regenerative Medicine, Faculty of Medicine Clínica Alemana-Universidad del Desarrollo, Santiago 7610658, Chile
| | - David J Orlicky
- Department of Pathology, University of Colorado Anschutz Medical Campus, University of Colorado Denver, Aurora, CO, USA
| | - Jaya Prakash Golla
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Rolando Garcia-Milian
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA; Bioinformatics Support Program, Cushing/Whitney Medical Library, Yale School of Medicine, New Haven, CT, 06210, USA
| | - Reza Aalizadeh
- Laboratory of Analytical Chemistry, Department of Chemistry, National Kapodistrian University of Athens University Campus, Zografou, 15771, Athens, Greece
| | - Nikolaos S Thomaidis
- Laboratory of Analytical Chemistry, Department of Chemistry, National Kapodistrian University of Athens University Campus, Zografou, 15771, Athens, Greece
| | - David C Thompson
- Department of Clinical Pharmacy, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of Colorado, Aurora, CO, USA
| | - Vasilis Vasiliou
- Department of Environmental Health Sciences, Yale School of Public Health, Yale University, New Haven, CT, USA.
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Wang L, Liu J, Miao Z, Pan Q, Cao W. Lipid droplets and their interactions with other organelles in liver diseases. Int J Biochem Cell Biol 2021; 133:105937. [PMID: 33529713 DOI: 10.1016/j.biocel.2021.105937] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/07/2020] [Accepted: 01/06/2021] [Indexed: 02/01/2023]
Abstract
Lipid droplets are cellular organelles used for lipid storage with a hydrophobic core of neutral lipids enclosed by a phospholipid monolayer. Besides presenting as giant single organelles in fat tissue, lipid droplets are also widely present as a multitude of small structures in hepatocytes, where they play key roles in health and disease of the liver. In addition to lipid storage, lipid droplets are also directly involved in lipid metabolism, membrane biosynthesis, cell signaling, inflammation, pathogen-host interaction and cancer development. In addition, they interact with other cellular organelles to regulate cellular biology. It is fair to say that the exact functions of lipid droplets in cellular physiology remain largely obscure. Thus prompted, here we aim to analyze the corpus of contemporary biomedical literature to create a framework as to how the role of lipid droplets in hepatocyte physiology and pathophysiology should be understood. The resulting framework should help understanding the interaction of lipid droplets with other organelles in important liver diseases, including fatty liver disease, viral hepatitis and liver cancer and direct further research directions.
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Affiliation(s)
- Ling Wang
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands
| | - Jiaye Liu
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands
| | - Zhijiang Miao
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands
| | - Qiuwei Pan
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands.
| | - Wanlu Cao
- Department of Gastroenterology and Hepatology, Erasmus MC-University Medical Center, Rotterdam, the Netherlands.
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Kim HH, Choi SE, Jeong WI. Oxidative stress and glutamate excretion in alcoholic steatosis: Metabolic synapse between hepatocyte and stellate cell. Clin Mol Hepatol 2020; 26:697-704. [PMID: 33053940 PMCID: PMC7641576 DOI: 10.3350/cmh.2020.0152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Accepted: 08/27/2020] [Indexed: 12/12/2022] Open
Abstract
Chronic alcohol consumption induces the development of alcoholic steatosis in the liver, which is one of the most widespread liver diseases worldwide. During general alcohol metabolism, hepatocytes generate mitochondria- and cytochrome P450 2E1 (CYP2E1)-mediated reactive oxygen species (ROS) whose accumulation elicits activation of the hepatic anti-oxidant system, including glutathione (GSH). However, chronic alcohol consumption decreases GSH generation through cysteine deficiency by suppressing the methionine cycle and trans-sulfuration system, whereas it turns on an alternative defense pathway, such as the xCT transporter, to compensate for GSH shortage. The xCT transporter mediates the uptake of cystine coupled to the efflux of glutamate, leading to an increase in blood glutamate. In response to the elevated glutamate in the liver, the expression of metabotropic glutamate receptor 5 (mGluR5) is up-regulated in hepatic stellate cells (HSCs) along with enhanced production of 2-arachidonoylglycerol, which in turn stimulates cannabinoid receptor 1 (CB1R) on neighboring hepatocytes to increase de novo lipogenesis. On the other hand, blockade of mGluR5 and CB1R attenuates alcoholic steatosis. Interestingly, although the increased expression of CYP2E1-mediated xCT and ROS generation are mainly observed at the perivenous area (zone 3), fat accumulation is mostly detected at hepatic zone 2. To resolve this discrepancy, this review summarizes recent advances on glutamate/mGluR5-derived alcoholic steatosis and zone-dependently different responses to alcohol intake. In addition, the bidirectional loop pathway and its unique metabolic synapse between hepatocytes and HSCs are discussed.
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Affiliation(s)
- Hee-Hoon Kim
- Lab of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Sung Eun Choi
- Lab of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Won-Il Jeong
- Lab of Liver Research, Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
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Valcin JA, Udoh US, Swain TM, Andringa KK, Patel CR, Al Diffalha S, Baker PRS, Gamble KL, Bailey SM. Alcohol and Liver Clock Disruption Increase Small Droplet Macrosteatosis, Alter Lipid Metabolism and Clock Gene mRNA Rhythms, and Remodel the Triglyceride Lipidome in Mouse Liver. Front Physiol 2020; 11:1048. [PMID: 33013449 PMCID: PMC7504911 DOI: 10.3389/fphys.2020.01048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Heavy alcohol drinking dysregulates lipid metabolism, promoting hepatic steatosis – the first stage of alcohol-related liver disease (ALD). The molecular circadian clock plays a major role in synchronizing daily rhythms in behavior and metabolism and clock disruption can cause pathology, including liver disease. Previous studies indicate that alcohol consumption alters liver clock function, but the impact alcohol or clock disruption, or both have on the temporal control of hepatic lipid metabolism and injury remains unclear. Here, we undertook studies to determine whether genetic disruption of the liver clock exacerbates alterations in lipid metabolism and worsens steatosis in alcohol-fed mice. To address this question, male liver-specific Bmal1 knockout (LKO) and flox/flox (Fl/Fl) control mice were fed a control or alcohol-containing diet for 5 weeks. Alcohol significantly dampened diurnal rhythms of mRNA levels in clock genes Bmal1 and Dbp, phase advanced Nr1d1/REV-ERBα, and induced arrhythmicity in Clock, Noct, and Nfil3/E4BP4, with further disruption in livers of LKO mice. Alcohol-fed LKO mice exhibited higher plasma triglyceride (TG) and different time-of-day patterns of hepatic TG and macrosteatosis, with elevated levels of small droplet macrosteatosis compared to alcohol-fed Fl/Fl mice. Diurnal rhythms in mRNA levels of lipid metabolism transcription factors (Srebf1, Nr1h2, and Ppara) were significantly altered by alcohol and clock disruption. Alcohol and/or clock disruption significantly altered diurnal rhythms in mRNA levels of fatty acid (FA) synthesis and oxidation (Acaca/b, Mlycd, Cpt1a, Fasn, Elovl5/6, and Fads1/2), TG turnover (Gpat1, Agpat1/2, Lpin1/2, Dgat2, and Pnpla2/3), and lipid droplet (Plin2/5, Lipe, Mgll, and Abdh5) genes, along with protein abundances of p-ACC, MCD, and FASN. Lipidomics analyses showed that alcohol, clock disruption, or both significantly altered FA saturation and remodeled the FA composition of the hepatic TG pool, with higher percentages of several long and very long chain FA in livers of alcohol-fed LKO mice. In conclusion, these results show that the liver clock is important for maintaining temporal control of hepatic lipid metabolism and that disrupting the liver clock exacerbates alcohol-related hepatic steatosis.
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Affiliation(s)
- Jennifer A Valcin
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Uduak S Udoh
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Telisha M Swain
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kelly K Andringa
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Chirag R Patel
- Division of Anatomic Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Sameer Al Diffalha
- Division of Anatomic Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
| | | | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Shannon M Bailey
- Division of Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, United States
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11
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Arumugam MK, Talawar S, Listenberger L, Donohue TM, Osna NA, Kharbanda KK. Role of Elevated Intracellular S-Adenosylhomocysteine in the Pathogenesis of Alcohol-Related Liver Disease. Cells 2020; 9:cells9061526. [PMID: 32585865 PMCID: PMC7349643 DOI: 10.3390/cells9061526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/19/2020] [Accepted: 06/21/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The earliest manifestation of alcohol-related liver disease (ALD) is steatosis, characterized by the accumulation of lipid droplets (LDs) in hepatocytes. Findings from our laboratory have indicated that many pathological changes, including steatosis, correlate with the alcohol-induced hepatocellular increases in S-adenosylhomocysteine (SAH). Based on these considerations, we hypothesized that an experimental increase in intracellular SAH alone will result in similar steatotic changes to those seen after alcohol exposure. METHODS Freshly isolated rat hepatocytes grown on collagen-coated plates were exposed to serum-free medium containing 50 µmol/L oleic acid and varying concentrations of 3-deazaadenosine (DZA) to experimentally elevate intracellular SAH levels. RESULTS Overnight exposure to DZA treatment dose-dependently increased hepatocellular triglyceride accumulation, which was also evident by morphological visualization of larger-sized LDs. The rise in triglycerides and LDs accompanied increases in mRNA and protein levels of several LD-associated proteins known to regulate LD number and size. Furthermore, DZA treatment caused a decline in the levels of lipases that prevent fat accumulation as well as increased the expression of factors involved in lipogenesis and fatty acid mobilization. Collectively, our results indicate that the elevation of intracellular SAH is sufficient to promote fat accumulation in hepatocytes, which is similar to that seen after alcohol exposure.
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Affiliation(s)
- Madan Kumar Arumugam
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Sharanappa Talawar
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Laura Listenberger
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA;
| | - Terrence M. Donohue
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Natalia A. Osna
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Kusum K. Kharbanda
- Research Service, Veterans Affairs Nebraska-Western Iowa Health Care System, Omaha, NE 68105, USA; (M.K.A.); (S.T.); (T.M.D.J.); (N.A.O.)
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
- Correspondence: ; Tel.: +1-402-995-3752; Fax: +1-402-995-4600
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12
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Abstract
The rising incidence of alcohol-related liver disease (ALD) demands making urgent progress in understanding the fundamental molecular basis of alcohol-related hepatocellular damage. One of the key early events accompanying chronic alcohol usage is the accumulation of lipid droplets (LDs) in the hepatocellular cytoplasm. LDs are far from inert sites of neutral lipid storage; rather, they represent key organelles that play vital roles in the metabolic state of the cell. In this review, we will examine the biology of these structures and outline recent efforts being made to understand the effects of alcohol exposure on the biogenesis, catabolism, and motility of LDs and how their dynamic nature is perturbed in the context of ALD.
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Affiliation(s)
- Ryan J. Schulze
- Department of Biochemistry and Molecular Biology and the Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA,Corresponding author. Department of Biochemistry and Molecular Biology and the Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA. (R.J. Schulze)
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology, and Therapeutics, The University of Kansas Medical Center, Kansas City, KS, USA
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13
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Shearn CT, Fennimore B, Orlicky DJ, Gao YR, Saba LM, Battista KD, Aivazidis S, Assiri M, Harris PS, Michel C, Merrill GF, Schmidt EE, Colgan SP, Petersen DR. Cholestatic liver disease results increased production of reactive aldehydes and an atypical periportal hepatic antioxidant response. Free Radic Biol Med 2019; 143:101-114. [PMID: 31377417 PMCID: PMC6848778 DOI: 10.1016/j.freeradbiomed.2019.07.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/30/2019] [Accepted: 07/31/2019] [Indexed: 01/22/2023]
Abstract
Cholangiopathies such as primary sclerosing cholangitis (PSC) are chronic liver diseases characterized by increased cholestasis, biliary inflammation and oxidative stress. The objective of this study was to elucidate the impact of cholestatic injury on oxidative stress-related factors. Using hepatic tissue and whole cell liver extracts (LE) isolated from 11-week old C57BL/6J (WT) and Mdr2KO mice, inflammation and oxidative stress was assessed. Concurrently, specific targets of carbonylation were assessed in LE prepared from murine groups as well as from normal and human patients with end-stage PSC. Identified carbonylated proteins were further evaluated using bioinformatics analyses. Picrosirius red staining revealed extensive fibrosis in Mdr2KO liver, and fibrosis colocalized with increased periportal inflammatory cells and both acrolein and 4-HNE staining. Western blot analysis revealed elevated periportal expression of antioxidant proteins Cbr3, GSTμ, Prdx5, TrxR1 and HO-1 but not GCLC, GSTπ or catalase in the Mdr2KO group when compared to WT. From immunohistochemical analysis, increased periportal reactive aldehyde production colocalized with elevated staining of Cbr3, GSTμ and TrxR1 but surprisingly not with Nrf2. Mass spectrometric analysis revealed an increase in carbonylated proteins in the Mdr2KO and PSC groups compared to respective controls. Gene ontology and KEGG pathway analysis of carbonylated proteins revealed a propensity for increased carbonylation of proteins broadly involved in metabolic processes as well more specifically in Rab-mediated signal transduction, lysosomes and the large ribosomal subunit in human PSC. Western blot analysis of Rab-GTPase expression revealed no significant differences in Mdr2KO mice when compared to WT livers. In contrast, PSC tissue exhibited decreased levels of Rabs 4, 5 and increased abundance of Rabs 6 and 9a protein. Results herein reveal that cholestasis induces stage-dependent increases in periportal oxidative stress responses and protein carbonylation, potentially contributing to pathogenesis in Mdr2KO. Furthermore, during early stage cholestasis, there is cell-specific upregulation of some but not all, antioxidant proteins.
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Affiliation(s)
- Colin T Shearn
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States.
| | - Blair Fennimore
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - David J Orlicky
- Department of Pathology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Yue R Gao
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Laura M Saba
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Kayla D Battista
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Stefanos Aivazidis
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Mohammed Assiri
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Peter S Harris
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Cole Michel
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Gary F Merrill
- Department of Biochemistry and Biophysics, Oregon State University, Corvalis, OR, 97331, United States
| | - Edward E Schmidt
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT, 59717, United States
| | - Sean P Colgan
- Department of Medicine, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
| | - Dennis R Petersen
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, United States
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14
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Pohanka M. Antidotes Against Methanol Poisoning: A Review. Mini Rev Med Chem 2019; 19:1126-1133. [PMID: 30864518 DOI: 10.2174/1389557519666190312150407] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/20/2019] [Accepted: 03/06/2019] [Indexed: 12/12/2022]
Abstract
Methanol is the simplest alcohol. Compared to ethanol that is fully detoxified by metabolism. Methanol gets activated in toxic products by the enzymes, alcohol dehydrogenase and aldehyde dehydrogenase. Paradoxically, the same enzymes convert ethanol to harmless acetic acid. This review is focused on a discussion and overview of the literature devoted to methanol toxicology and antidotal therapy. Regarding the antidotal therapy, three main approaches are presented in the text: 1) ethanol as a competitive inhibitor in alcohol dehydrogenase; 2) use of drugs like fomepizole inhibiting alcohol dehydrogenase; 3) tetrahydrofolic acid and its analogues reacting with the formate as a final product of methanol metabolism. All the types of antidotal therapies are described and how they protect from toxic sequelae of methanol is explained.
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Affiliation(s)
- Miroslav Pohanka
- Faculty of Military Health Sciences, University of Defense, Trebesska 1575, Hradec Kralove CZ-50001, Czech Republic
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15
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Gu Y, Yang Y, Cao X, Zhao Y, Gao X, Sun C, Zhang F, Yuan Y, Xu Y, Zhang J, Xiao L, Ye J. Plin3 protects against alcoholic liver injury by facilitating lipid export from the endoplasmic reticulum. J Cell Biochem 2019; 120:16075-16087. [PMID: 31119787 DOI: 10.1002/jcb.28889] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 03/01/2019] [Accepted: 03/15/2019] [Indexed: 12/20/2022]
Abstract
Hepatic lipid accumulation is the most common pathological characteristic of alcoholic liver disease (ALD). In mammalian cells, excess neutral lipids are stored in lipid droplets (LDs). As a member of perilipin family proteins, Plin3 was recently found to regulate the LD biogenesis. However, the roles and mechanism of Plin3 in ALD progression remain unclear. Herein, we found that alcohol stimulated Plin3 expression in both mouse livers and cultured AML12 mouse hepatic cells, which was accompanied by excess LD accumulation in hepatocytes. The elevations of Plin3 in alcohol-treated hepatocytes paralleled with the levels of both PPARα and γ, and the protein degradation of Plin3 was also reduced after alcohol exposure. Moreover, Plin3 knockdown increased cellular sensitivity to alcohol-induced apoptosis, endoplasmic reticulum (ER) stress, and inflammatory cytokines release, including TNF-α, IL-1, and IL-6β. Notably, alcohol exacerbated triglycerides (TG) accumulation in the ER and caused ER dilation in Plin3-knockdown AML12 cells. Finally, we observed that Plin3 interacted with dynein subunit Dync1i1 and mediated the colocalization of LDs and microtubules, while high concentration of alcohol disrupted microtubules and caused dispersion of excess small LDs in cytoplasm. Summarily, Plin3 promotes lipid export from the ER and reduces ER lipotoxic stress, thereby, protecting against alcoholic liver injury. Moreover, Plin3 could be an adapter protein mediating LD transport by microtubules. This study explored the roles of Plin3 in alcohol-induced hepatic injury, suggesting Plin3 as a potential target for the prevention of ALD progression.
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Affiliation(s)
- Yu Gu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Ying Yang
- Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xiangmei Cao
- Department of Pathology, Basic Medical School, Ningxia Medical University, Yinchuan, Ningxia, China
| | - Yuanlin Zhao
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xing Gao
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Chao Sun
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Neurology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Feng Zhang
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yuan Yuan
- Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yuqiao Xu
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jin Zhang
- Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Liming Xiao
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Ye
- State Key Laboratory of Cancer Biology and Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.,Department of Pathology, Basic Medicine School, The Fourth Military Medical University, Xi'an, Shaanxi, China
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16
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Ali HR, Assiri MA, Harris PS, Michel CR, Yun Y, Marentette JO, Huynh FK, Orlicky DJ, Shearn CT, Saba LM, Reisdorph R, Reisdorph N, Hirschey MD, Fritz KS. Quantifying Competition among Mitochondrial Protein Acylation Events Induced by Ethanol Metabolism. J Proteome Res 2019; 18:1513-1531. [PMID: 30644754 DOI: 10.1021/acs.jproteome.8b00800] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mitochondrial dysfunction is one of many key factors in the etiology of alcoholic liver disease (ALD). Lysine acetylation is known to regulate numerous mitochondrial metabolic pathways, and recent reports demonstrate that alcohol-induced protein acylation negatively impacts these processes. To identify regulatory mechanisms attributed to alcohol-induced protein post-translational modifications, we employed a model of alcohol consumption within the context of wild type (WT), sirtuin 3 knockout (SIRT3 KO), and sirtuin 5 knockout (SIRT5 KO) mice to manipulate hepatic mitochondrial protein acylation. Mitochondrial fractions were examined by label-free quantitative HPLC-MS/MS to reveal competition between lysine acetylation and succinylation. A class of proteins defined as "differential acyl switching proteins" demonstrate select sensitivity to alcohol-induced protein acylation. A number of these proteins reveal saturated lysine-site occupancy, suggesting a significant level of differential stoichiometry in the setting of ethanol consumption. We hypothesize that ethanol downregulates numerous mitochondrial metabolic pathways through differential acyl switching proteins. Data are available via ProteomeXchange with identifier PXD012089.
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Affiliation(s)
- Hadi R Ali
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Mohammed A Assiri
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Peter S Harris
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Cole R Michel
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Youngho Yun
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - John O Marentette
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Frank K Huynh
- Department of Biological Sciences , San Jose State University , San Jose , California 95192 , United States
| | - David J Orlicky
- Department of Pathology, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Colin T Shearn
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Laura M Saba
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Richard Reisdorph
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Nichole Reisdorph
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
| | - Matthew D Hirschey
- Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Department of Pharmacology and Cancer Biology , Duke University Medical Center , Durham , North Carolina 27710 , United States
| | - Kristofer S Fritz
- Skaggs School of Pharmacy and Pharmaceutical Sciences , University of Colorado Anschutz Medical Campus , Aurora , Colorado 80045 , United States
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17
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Listenberger L, Townsend E, Rickertsen C, Hains A, Brown E, Inwards EG, Stoeckman AK, Matis MP, Sampathkumar RS, Osna NA, Kharbanda KK. Decreasing Phosphatidylcholine on the Surface of the Lipid Droplet Correlates with Altered Protein Binding and Steatosis. Cells 2018; 7:cells7120230. [PMID: 30477200 PMCID: PMC6316228 DOI: 10.3390/cells7120230] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/19/2018] [Accepted: 11/22/2018] [Indexed: 02/05/2023] Open
Abstract
Alcoholic fatty liver disease (AFLD) is characterized by an abnormal accumulation of lipid droplets (LDs) in the liver. Here, we explore the composition of hepatic LDs in a rat model of AFLD. Five to seven weeks of alcohol consumption led to significant increases in hepatic triglyceride mass, along with increases in LD number and size. Additionally, hepatic LDs from rats with early alcoholic liver injury show a decreased ratio of surface phosphatidylcholine (PC) to phosphatidylethanolamine (PE). This occurred in parallel with an increase in the LD association of perilipin 2, a prominent LD protein. To determine if changes to the LD phospholipid composition contributed to differences in protein association with LDs, we constructed liposomes that modeled the LD PC:PE ratios in AFLD and control rats. Reducing the ratio of PC to PE increased the binding of perilipin 2 to liposomes in an in vitro experiment. Moreover, we decreased the ratio of LD PC:PE in NIH 3T3 and AML12 cells by culturing these cells in choline-deficient media. We again detected increased association of specific LD proteins, including perilipin 2. Taken together, our experiments suggest an important link between LD phospholipids, protein composition, and lipid accumulation.
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Affiliation(s)
- Laura Listenberger
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA.
| | - Elizabeth Townsend
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA.
| | - Cassandra Rickertsen
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA.
| | - Anastasia Hains
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA.
| | - Elizabeth Brown
- Departments of Biology and Chemistry, St. Olaf College, Northfield, MN 55057, USA.
| | - Emily G Inwards
- Department of Chemistry, Bethel University, St. Paul, MN 55112, USA.
| | | | - Mitchell P Matis
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE and Departments of Internal Medicine and Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68105, USA.
| | - Rebecca S Sampathkumar
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE and Departments of Internal Medicine and Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68105, USA.
| | - Natalia A Osna
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE and Departments of Internal Medicine and Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68105, USA.
| | - Kusum K Kharbanda
- Research Service, VA Nebraska-Western Iowa Health Care System, Omaha, NE and Departments of Internal Medicine and Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68105, USA.
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18
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Ali H, Assiri MA, Shearn CT, Fritz KS. Lipid peroxidation derived reactive aldehydes in alcoholic liver disease. CURRENT OPINION IN TOXICOLOGY 2018; 13:110-117. [PMID: 31263795 DOI: 10.1016/j.cotox.2018.10.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Lipid peroxidation is a known consequence of oxidative stress and is thought to play a key role in numerous disease pathologies, including alcoholic liver disease (ALD). The overaccumulation of lipid peroxidation products during chronic alcohol consumption results in pathogenic lesions on protein, DNA, and lipids throughout the cell. Molecular adducts due to secondary end products of lipid peroxidation impact a host of biochemical processes, including inflammation, antioxidant defense, and metabolism. The aggregate burden of lipid peroxidation which occurs due to chronic alcohol metabolism, including downstream signaling events, contributes to the development and progression of ALD. In this current opinion we highlight recent studies and approaches relating cellular mechanisms of lipid peroxidation to the pathogenesis of alcoholic liver disease.
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Affiliation(s)
- Hadi Ali
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Mohammed A Assiri
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Colin T Shearn
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
| | - Kristofer S Fritz
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO
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19
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Lanaspa MA, Andres-Hernando A, Orlicky DJ, Cicerchi C, Jang C, Li N, Milagres T, Kuwabara M, Wempe MF, Rabinowitz JD, Johnson RJ, Tolan DR. Ketohexokinase C blockade ameliorates fructose-induced metabolic dysfunction in fructose-sensitive mice. J Clin Invest 2018. [PMID: 29533924 DOI: 10.1172/jci94427] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Increasing evidence suggests a role for excessive intake of fructose in the Western diet as a contributor to the current epidemics of metabolic syndrome and obesity. Hereditary fructose intolerance (HFI) is a difficult and potentially lethal orphan disease associated with impaired fructose metabolism. In HFI, the deficiency of aldolase B results in the accumulation of intracellular phosphorylated fructose, leading to phosphate sequestration and depletion, increased adenosine triphosphate (ATP) turnover, and a plethora of conditions that lead to clinical manifestations such as fatty liver, hyperuricemia, Fanconi syndrome, and severe hypoglycemia. Unfortunately, there is currently no treatment for HFI, and avoiding sugar and fructose has become challenging in our society. In this report, through use of genetically modified mice and pharmacological inhibitors, we demonstrate that the absence or inhibition of ketohexokinase (Khk), an enzyme upstream of aldolase B, is sufficient to prevent hypoglycemia and liver and intestinal injury associated with HFI. Herein we provide evidence for the first time to our knowledge of a potential therapeutic approach for HFI. Mechanistically, our studies suggest that it is the inhibition of the Khk C isoform, not the A isoform, that protects animals from HFI.
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Affiliation(s)
- Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Ana Andres-Hernando
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - David J Orlicky
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Christina Cicerchi
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Cholsoon Jang
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Nanxing Li
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Tamara Milagres
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Masanari Kuwabara
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Michael F Wempe
- Department of Pharmacology, University of Colorado, Aurora, Colorado, USA
| | - Joshua D Rabinowitz
- Department of Chemistry and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado, Aurora, Colorado, USA
| | - Dean R Tolan
- Department of Biology, Boston University, Boston, Massachusetts, USA
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20
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Hege M, Jung F, Sellmann C, Jin C, Ziegenhardt D, Hellerbrand C, Bergheim I. An iso-α-acid-rich extract from hops (Humulus lupulus) attenuates acute alcohol-induced liver steatosis in mice. Nutrition 2017; 45:68-75. [PMID: 29129239 DOI: 10.1016/j.nut.2017.07.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 06/29/2017] [Accepted: 07/16/2017] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Results of in vitro and in vivo studies suggest that consumption of beer is less harmful for the liver than consumption of spirits. It also has been suggested that secondary plant compounds derived from hops such as xanthohumol or iso-α-acids may have beneficial effects on the development of liver diseases of various etiologies. The aim of this study was to determine whether iso-α-acids consumed in doses achieved by "normal" beer consumption have beneficial effects on health. METHODS Female C57 Bl/6 J mice, pretreated for 4 d with an iso-α-acid-rich extract (∼30% iso-α-acids from hops, 0.75 mg/kg body weight), were fed one bolus of ethanol (6 g/kg body weight intragastric) or an iso-caloric maltodextrin solution. Markers of liver damage, toll-like receptor-4 signaling, and lipid peroxidation were determined. Furthermore, the effect of isohumulone on the lipopolysaccharide-dependent activation of J774 A.1 macrophages, used as a model of Kupffer cells, was determined. RESULTS In the liver, acute ethanol administration led to a significant accumulation of fat (∼10-fold), which was accompanied by significantly higher inducible nitric oxide synthase protein level, elevated nitric oxide production, and increased plasminogen activator inhibitor 1 protein concentration when compared to controls. In mice pretreated with iso-α-acids, these effects of alcohol were markedly attenuated. Pretreatment of J774 A.1 macrophages with isohumulone significantly attenuated lipopolysaccharide-induced mRNA expression of inducible nitric oxide synthase and interleukin-6 as well as the release of nitric oxide. CONCLUSION Taken together, iso-α-acids markedly attenuated the development of acute alcohol-induced damage in mice.
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Affiliation(s)
- Marianne Hege
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany
| | - Finn Jung
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany; Department of Nutritional Sciences, Molecular Nutritional Science, University Vienna, Vienna, Austria
| | - Cathrin Sellmann
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany
| | - Chengjun Jin
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany
| | - Doreen Ziegenhardt
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany
| | - Claus Hellerbrand
- Department of Internal Medicine I, University of Regensburg, Regensburg, Germany; Institute of Biochemistry, Emil-Fischer-Zentrum, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Ina Bergheim
- Institute of Nutrition, SD Model Systems of Molecular Nutrition, Friedrich-Schiller-University Jena, Jena, Germany; Department of Nutritional Sciences, Molecular Nutritional Science, University Vienna, Vienna, Austria.
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21
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Natarajan SK, Rasineni K, Ganesan M, Feng D, McVicker BL, McNiven MA, Osna NA, Mott JL, Casey CA, Kharbanda KK. Structure, Function and Metabolism of Hepatic and Adipose Tissue Lipid Droplets: Implications in Alcoholic Liver Disease. Curr Mol Pharmacol 2017; 10:237-248. [PMID: 26278390 PMCID: PMC4820363 DOI: 10.2174/1874467208666150817111727] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/07/2015] [Accepted: 08/07/2015] [Indexed: 02/08/2023]
Abstract
For more than 30 years, lipid droplets (LDs) were considered as an inert bag of lipid for storage of energy-rich fat molecules. Following a paradigm shift almost a decade ago, LDs are presently considered an active subcellular organelle especially designed for assembling, storing and subsequently supplying lipids for generating energy and membrane synthesis (and in the case of hepatocytes for VLDL secretion). LDs also play a central role in many other cellular functions such as viral assembly and protein degradation. Here, we have explored the structural and functional changes that occur in hepatic and adipose tissue LDs following chronic ethanol consumption in relation to their role in the pathogenesis of alcoholic liver injury.
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Affiliation(s)
| | - Karuna Rasineni
- Research Service, VA Nebraska-Western Iowa Health Care System (VA NWIHCS). 0
| | - Murali Ganesan
- Research Service, VA Nebraska-Western Iowa Health Care System (VA NWIHCS). 0
| | - Dan Feng
- Research Service, VA Nebraska-Western Iowa Health Care System (VA NWIHCS). 0
| | - Benita L McVicker
- Research Service, VA Nebraska-Western Iowa Health Care System (VA NWIHCS). 0
| | - Mark A McNiven
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota. United States
| | - Natalia A Osna
- Research Service, VA Nebraska-Western Iowa Health Care System (VA NWIHCS). 0
| | - Justin L Mott
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center. 0
| | - Carol A Casey
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center. 0
| | - Kusum K Kharbanda
- Veterans Affairs Nebraska Western Iowa Health Care System, Research Service (151), 4101 Woolworth Avenue, Omaha, Nebraska, 68105. United States
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22
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Xu W, Lu C, Yao L, Zhang F, Shao J, Zheng S. Dihydroartemisinin protects against alcoholic liver injury through alleviating hepatocyte steatosis in a farnesoid X receptor-dependent manner. Toxicol Appl Pharmacol 2016; 315:23-34. [PMID: 27939985 DOI: 10.1016/j.taap.2016.12.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 11/29/2016] [Accepted: 12/04/2016] [Indexed: 02/06/2023]
Abstract
Alcoholic liver disease (ALD) is a common etiology of liver diseases, characterized by hepatic steatosis. We previously identified farnesoid X receptor (FXR) as a potential therapeutic target for ALD. Dihydroartemisinin (DHA) has been recently identified to possess potent pharmacological activities on liver diseases. This study was aimed to explore the impact of DHA on ALD and further elaborate the underlying mechanisms. Gain- or loss-of-function analyses of FXR were applied in both in vivo and in vitro studies. Results demonstrated that DHA rescued FXR expression and activity in alcoholic rat livers. DHA also reduced serodiagnostic markers of liver injury, including aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase. DHA improved alcohol-induced liver histological lesions, expression of inflammation genes, and inflammatory cell infiltration. In addition, DHA not only attenuated hyperlipidemia but also reduced hepatic steatosis through regulating lipogenesis and lipolysis genes. In vitro experiments further consolidated the concept that DHA ameliorated ethanol-caused hepatocyte injury and steatosis. Noteworthily, DHA effects were reinforced by FXR agonist obeticholic acid or FXR expression plasmids but abrogated by FXR antagonist Z-guggulsterone or FXR siRNA. In summary, DHA significantly improved alcoholic liver injury by inhibiting hepatic steatosis, which was dependent on its activation of FXR in hepatocytes.
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Affiliation(s)
- Wenxuan Xu
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China
| | - Chunfeng Lu
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China
| | - Lu Yao
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China
| | - Feng Zhang
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China
| | - Jiangjuan Shao
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China
| | - Shizhong Zheng
- Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China; Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province, China.
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23
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Tang L, Yang F, Fang Z, Hu C. Resveratrol Ameliorates Alcoholic Fatty Liver by Inducing Autophagy. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2016; 44:1207-1220. [DOI: 10.1142/s0192415x16500671] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Alcoholic fatty liver (AFL) is early stage of alcoholic liver disease, which can progress to steatohepatitis, fibrosis, and cirrhosis if alcohol consumption is continued. The pathogenesis of AFL is associated with excessive lipid accumulation in hepatocytes. Resveratrol (RES), a dietary polyphenol found in red wines and grapes, has been shown to have a hepatoprotective effect. Autophagy is a crucial physiological process in cellular catabolism that involves the regulation of lipid droplets. Autophagy maintains a balance between protein synthesis, degradation and self-recycling. In the present study, we evaluated the protective effects of RES (10[Formula: see text]mg/kg, 30[Formula: see text]mg/kg, 100[Formula: see text]mg/kg) on AFL mice fed with an ethanol Lieber-DeCarli liquid diet, and HepG2 cells in the presence of oleic acid and alcohol to investigate whether resveratrol could induce autophagy to attenuate lipid accumulation. The results showed that RES (30[Formula: see text]mg/kg and 100[Formula: see text]mg/kg) treatment significantly attenuated hepatic steatosis and lowered the activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG), low density lipoprotein cholesterol (LDL-C). H&E staining showed that RES reduced hepatic lipid accumulation. Transmission electron microscopy (TEM) images showed that RES treatment increased the number of autophagosomes and promoted the formation of autophagy. Western blot analysis showed that RES treatment increased the levels of microtubule-associated protein light chain3- II (LC3-II) and Beclin1, decreased expression of p62 protein. In addition, in vitro studies also demonstrated that RES led to the formation of acidic vesicular organelles (AVOs), however, 3-Methyladenine (3-MA), a specific inhibitor of autophagy, obviously inhibited the above effects of RES. In conclusion, RES has protective effects on alcoholic hepatic steatosis, and the potential mechanism might be involved in inducing autophagy.
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Affiliation(s)
- Liying Tang
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, Anhui, P.R. China
- Pharmacy Department, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, P.R. China
| | - Fengli Yang
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, Anhui, P.R. China
| | - Zhirui Fang
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, Anhui, P.R. China
| | - Chengmu Hu
- School of Pharmacy, Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei 230032, Anhui, P.R. China
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24
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Tang LY, Chen Y, Rui BB, Hu CM. Resveratrol ameliorates lipid accumulation in HepG2 cells, associated with down-regulation of lipin1 expression. Can J Physiol Pharmacol 2016; 94:185-189. [DOI: 10.1139/cjpp-2015-0125] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The pathogenesis of alcoholic fatty liver (AFL) disease is associated with the excessive accumulation of lipids in hepatocytes as well as oxidative stress. Resveratrol (RES), a dietary polyphenol found in red wine and grapes, has been shown to protect against AFL disease. However, the precise mechanisms that lead to this protective effect remain elusive. In this study, we used HepG2 cells to investigate the effects of RES on lipid metabolism and the mechanisms underlying these effects. HepG2 cells were cultured with oleic acid and alcohol for 48 h to induce excessive lipid accumulation. Oil red O staining showed that administration of oleic acid and alcohol induced more lipid accumulation than was observed in the control group, and that RES (15, 45, or 135 μmol/L) treatment reduced intracellular lipid droplets. RES treatment also significantly attenuated hepatic steatosis and lowered levels of intracellular triglycerides (TG). Western blot analysis showed that RES enhanced the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) and down-regulated the expression of sterol regulatory element-binding protein 1c (SREBP-1c) and lipin1. However, compound C, an AMPK inhibitor, reversed these effects of RES. In conclusion, RES reduced lipid accumulation and protected HepG2 cells. This effect may be associated with the down-regulation of SREBP-1c and lipin1 expression, increased levels of phosphorylated AMPK and ACC, and the activation of AMPK–lipin1 signaling.
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Affiliation(s)
- Li Ying Tang
- School of Pharmacy, Anhui Medical University, Anhui Key Laboratory of Bioactivity of Natural Products, 81 Meishan Road, Hefei 230032, Anhui Province, China
| | - Yi Chen
- Pharmacy department, Anhui No. 2 Province People’s Hospital, 1868 DangShan Road, Hefei, Anhui Province, China
| | - Bei Bei Rui
- Pharmacy department, Anhui No. 2 Province People’s Hospital, 1868 DangShan Road, Hefei, Anhui Province, China
| | - Cheng Mu Hu
- School of Pharmacy, Anhui Medical University, Anhui Key Laboratory of Bioactivity of Natural Products, 81 Meishan Road, Hefei 230032, Anhui Province, China
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25
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Shearn CT, Orlicky DJ, Saba LM, Shearn AH, Petersen DR. Increased hepatocellular protein carbonylation in human end-stage alcoholic cirrhosis. Free Radic Biol Med 2015; 89:1144-53. [PMID: 26518673 PMCID: PMC4762037 DOI: 10.1016/j.freeradbiomed.2015.10.420] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 10/20/2015] [Accepted: 10/25/2015] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Oxidative stress is a significant contributing factor in the pathogenesis of alcoholic liver disease (ALD). In the murine models of chronic alcohol consumption, induction of oxidative stress results in increased peroxidation of polyunsaturated fatty acids to form highly reactive electrophilic α/β unsaturated aldehydes that post-translationally modify proteins altering activity. Data are presented here suggesting that oxidative stress and the resulting carbonylation of hepatic proteins is an ongoing process involved in alcohol-induced cirrhosis. METHODS Using age-matched pooled hepatic tissue obtained from healthy humans and patients with end stage cirrhotic ALD, overall carbonylation was assessed by immunohistochemistry and LC-MS/MS of streptavidin purified hepatic whole cell extracts treated with biotin hydrazide. Identified carbonylated proteins were further evaluated using bioinformatics analyses. RESULTS Using immunohistochemistry and Western blotting, protein carbonylation was increased in end stage ALD occurring primarily in hepatocytes. Mass spectrometric analysis revealed a total of 1224 carbonylated proteins in normal hepatic and end-stage alcoholic cirrhosis tissue. Of these, 411 were unique to cirrhotic ALD, 261 unique to normal hepatic tissue and 552 common to both groups. Bioinformatic pathway analysis of hepatic carbonylated proteins revealed a propensity of long term EtOH consumption to increase post-translational carbonylation of proteins involved in glutathione homeostatic, glycolytic and cytoskeletal pathways. Western analysis revealed increased expression of GSTA4 and GSTπ in human ALD. Using LC-MS/MS analysis, a nonenaldehyde post-translational modification was identified on Lysine 235 of the cytoskeletal protein vimentin in whole cell extracts prepared from human end stage ALD hepatic tissue. CONCLUSIONS These studies are the first to use LC-MS/MS analysis of carbonylated proteins in human ALD and begin exploring possible mechanistic links with end-stage alcoholic cirrhosis and oxidative stress.
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Affiliation(s)
- C T Shearn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver Anschutz Medical Campus, 12850 East Montview Blvd Box C238, Building V20 Room 2131, Aurora, CO 80045, United States.
| | - D J Orlicky
- Department of Pathology, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, United States
| | - L M Saba
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver Anschutz Medical Campus, 12850 East Montview Blvd Box C238, Building V20 Room 2131, Aurora, CO 80045, United States
| | - A H Shearn
- Alpine Achievement Systems, Inc., 9635 Maroon Circle, Suite 120, Englewood, CO 80112, United States
| | - Dennis R Petersen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver Anschutz Medical Campus, 12850 East Montview Blvd Box C238, Building V20 Room 2131, Aurora, CO 80045, United States.
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26
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Rui BB, Chen H, Jang L, Li Z, Yang JM, Xu WP, Wei W. Melatonin Upregulates the Activity of AMPK and Attenuates Lipid Accumulation in Alcohol-induced Rats. Alcohol Alcohol 2015; 51:11-9. [PMID: 26564773 DOI: 10.1093/alcalc/agv126] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 09/28/2015] [Indexed: 12/14/2022] Open
Abstract
AIMS Melatonin is supposed to be an effective hepatoprotective agent. The effects and mechanisms of melatonin on alcoholic fatty liver (AFL) have not been well explored. The aim of this study was to investigate the preventive and therapeutic effects of melatonin on alcohol-induced fatty liver rats. METHODS The AFL rats were induced by intragastric infusion of alcohol plus a high-fat diet for 6 weeks, and melatonin (10, 20, 40 mg/kg) was administered by gastric perfusion. We also established fatty acid overload cell model in HepG2 cells to investigate the effect of melatonin on AMP-activated protein kinase (AMPK) activity. RESULTS The results showed that melatonin (20 and 40 mg/kg) administration significantly reduced alcohol-induced hepatic steatosis with lowering activities of serum alanine aminotransferase, aspartate aminotransferase and levels of serum and hepatic triglyceride. The activity of superoxide dismutase was increased and the content of malondialdehyde was decreased in liver homogenates of rats treated with melatonin. Melatonin increased the phosphorylation of AMPK in the liver tissues of alcohol-induced rats as well. Additionally, in vitro studies showed that melatonin increased the expression of melatonin1A receptor (MT1R), whereas luzindole, a receptor antagonist of melatonin, had no effect on its expression. In addition, melatonin reduced the levels of adenosine 3',5'-cyclic monophosphate (cAMP) and increased the phosphorylation of AMPK, and melatonin treatment could markedly reverse these effects. CONCLUSION In conclusion, melatonin could protect against liver injury caused by alcohol gastric perfusion. The effect may be related to alleviating lipid peroxidation and upregulating the activity of AMPK mediated by MT1R signaling pathway.
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Affiliation(s)
- Bei-bei Rui
- Anhui No. 2 Province People's Hospital, Hefei, Anhui 200041, China
| | - Hao Chen
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei 230032, China
| | - Lei Jang
- Anhui No. 2 Province People's Hospital, Hefei, Anhui 200041, China
| | - Zhen Li
- Anhui No. 2 Province People's Hospital, Hefei, Anhui 200041, China
| | - Jing-mo Yang
- Anhui Provincial Cancer Hospital, Hefei, Anhui 230001, China
| | - Wei-ping Xu
- Anhui Medical University affiliated Provincial Hospital, Hefei, Anhui 230001, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Hefei 230032, China
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Carr RM, Ahima RS. Pathophysiology of lipid droplet proteins in liver diseases. Exp Cell Res 2015; 340:187-92. [PMID: 26515554 DOI: 10.1016/j.yexcr.2015.10.021] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/21/2015] [Accepted: 10/23/2015] [Indexed: 02/07/2023]
Abstract
Cytosolic lipid droplets (LDs) are present in most cell types, and consist of a core comprising neutral lipids, mainly triglycerides and sterol esters, surrounded by a monolayer of phospholipids. LDs are heterogeneous in their structure, chemical composition, and tissue distribution. LDs are coated by several proteins, including perilipins and other structural proteins, lipogenic enzymes, lipases and membrane-trafficking proteins. Five proteins of the perilipin (PLIN) family (PLIN1 (perilipin), PLIN2 (adipose differentiation-related protein), PLIN3 (tail-interacting protein of 47kDa), PLIN4 (S3-12), and PLIN5 (myocardial lipid droplet protein)), are associated with LD formation. More recently, the CIDE family of proteins, hypoxia-inducible protein 2 (HIG2), and patanin-like phospholipase domain-containing 3 (PNPLA3) have also gained attention in hepatic LD biology. Evidence suggests that LD proteins are involved in the pathophysiology of fatty liver diseases characterized by excessive lipid accumulation in hepatocytes. This review article will focus on how hepatic LDs and their associated proteins are involved in the pathogenesis of three chronic liver conditions: hepatitis C virus infection, non-alcoholic fatty liver disease, and alcoholic liver disease.
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Affiliation(s)
- Rotonya M Carr
- Department of Medicine, Gastroenterology and Hepatology Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
| | - Rexford S Ahima
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA
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28
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Ikura Y, Caldwell SH. Lipid droplet-associated proteins in alcoholic liver disease: a potential linkage with hepatocellular damage. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:8699-8708. [PMID: 26464614 PMCID: PMC4583846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 07/29/2015] [Indexed: 06/05/2023]
Abstract
Steatosis is a characteristic morphological change of alcoholic liver disease, but its pathologic significance is still obscure. Regardless of cell types, intracellular lipid droplets are coated with a phospholipid monolayer, on which many kinds of lipid droplet-associated proteins are present. These proteins, such as the perilipin family of proteins and the cell death inducing DNA fragmentation factor (DFF) 45-like effectors, are recognized to play important roles in lipid metabolism in the physiological settings. In addition, recent lipidology studies have revealed that expression of the lipid droplet-associated proteins possibly participate in the pathologic processes of many metabolic disorders, including fatty liver and insulin resistance. Hence, controlling protein expressions is expected to offer novel therapeutic options. In this review, we summarize collected data concerning the potential contribution of the lipid droplet-associated proteins to the development of alcoholic fatty liver. Without exception, existing data indicates that the lipid droplet-associated proteins, especially the perilipin family proteins, are important factors in alcoholic fatty liver. These proteins exert a prosteatotic effect, and their expression is closely associated with lipotoxicity based on endoplasmic reticulum stress and oxidative injury. Although suppression of their expression may be beneficial, careful consideration is required because these proteins simultaneously function as protective factors against lipotoxicity.
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Affiliation(s)
- Yoshihiro Ikura
- Department of Pathology, Takatsuki General Hospital1-3-13, Kosobecho, Takatsuki 569-1192, Japan
| | - Stephen H Caldwell
- Division of Gastroenterology and Hepatology, University of VirginiaCharlottesville, Virginia 22908-0708, USA
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Moderate alcohol consumption diminishes the development of non-alcoholic fatty liver disease (NAFLD) in ob/ob mice. Eur J Nutr 2015; 55:1153-64. [PMID: 26003186 DOI: 10.1007/s00394-015-0929-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 05/14/2015] [Indexed: 02/07/2023]
Abstract
PURPOSE Using ob/ob mice as a model of non-alcoholic fatty liver disease (NAFLD), we investigated the effect of moderate alcohol intake on the development of NAFLD and molecular mechanisms involved. METHODS Ob/ob mice were fed water or ethanol solution (2.5 g/kg body weight/day) for 6 weeks, and markers of liver injury, insulin signalling and adiponectin in visceral adipose tissue were determined. RESULTS Whereas bodyweight and the degree of liver steatosis did not differ among ob/ob mouse groups, those consuming ethanol had markedly less macrovesicular hepatic fat accumulation, inflammatory alterations and significantly lower transaminase levels. Despite similarly elevated protein levels of tumour necrosis factor α, protein concentrations of plasminogen activator inhibitor 1 were significantly lower in livers of ob/ob mice consuming ethanol in comparison with controls. The hepato-protective property of moderate alcohol ingestion in ob/ob mice was associated with an induction of the sirtuin-1/adiponectin-signalling cascade in visceral fat tissue and an activation of Akt in the liver. Similar effects of moderate alcohol exposure were also found in vitro in 3T3-L1 and AML-12 cells. CONCLUSION These data suggest that moderate alcohol intake may diminish the development of NAFLD through sirtuin-1/-adiponectin-dependent signalling cascades.
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30
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Gross DA, Silver DL. Cytosolic lipid droplets: from mechanisms of fat storage to disease. Crit Rev Biochem Mol Biol 2015; 49:304-26. [PMID: 25039762 DOI: 10.3109/10409238.2014.931337] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The lipid droplet (LD) is a phylogenetically conserved organelle. In eukaryotes, it is born from the endoplasmic reticulum, but unlike its parent organelle, LDs are the only known cytosolic organelles that are micellar in structure. LDs are implicated in numerous physiological and pathophysiological functions. Many aspects of the LD has captured the attention of diverse scientists alike and has recently led to an explosion in information on the LD biogenesis, expansion and fusion, identification of LD proteomes and diseases associated with LD biology. This review will provide a brief history of this fascinating organelle and provide some contemporary views of unanswered questions in LD biogenesis.
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Affiliation(s)
- David A Gross
- Program in Cardiovascular & Metabolic Disorders, Duke-NUS Graduate Medical School Singapore , Singapore , and
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Carr RM, Peralta G, Yin X, Ahima RS. Absence of perilipin 2 prevents hepatic steatosis, glucose intolerance and ceramide accumulation in alcohol-fed mice. PLoS One 2014; 9:e97118. [PMID: 24831094 PMCID: PMC4022498 DOI: 10.1371/journal.pone.0097118] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/14/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Perilipin 2 (Plin2) is a lipid droplet protein that has roles in both lipid and glucose homeostasis. An increase in Plin2 in liver is associated with the development of steatosis, glucose intolerance, and ceramide accumulation in alcoholic liver disease. We investigated the role of Plin2 on energy balance and glucose and lipid homeostasis in wildtype and Plin2 knockout (Plin2KO) mice chronically fed a Lieber-DeCarli liquid ethanol or control diet for six weeks. METHODS We performed in vivo measurements of energy intake and expenditure; body composition; and glucose tolerance. After sacrifice, liver was dissected for histology and lipid analysis. RESULTS We found that neither genotype nor diet had a significant effect on final weight, body composition, or energy intake between WT and Plin2KO mice fed alcohol or control diets. Additionally, alcohol feeding did not affect oxygen consumption or carbon dioxide production in Plin2KO mice. We performed glucose tolerance testing and observed that alcohol feeding failed to impair glucose tolerance in Plin2KO mice. Most notably, absence of Plin2 prevented hepatic steatosis and ceramide accumulation in alcohol-fed mice. These changes were related to downregulation of genes involved in lipogenesis and triglyceride synthesis. CONCLUSIONS Plin2KO mice chronically fed alcohol are protected from hepatic steatosis, glucose intolerance, and hepatic ceramide accumulation, suggesting a critical pathogenic role of Plin2 in experimental alcoholic liver disease.
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Affiliation(s)
- Rotonya M. Carr
- University of Pennsylvania, Perelman School of Medicine, Department of Medicine, Gastroenterology Division, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Giselle Peralta
- University of Pennsylvania, Perelman School of Medicine, Institute for Diabetes, Obesity and Metabolism, Philadelphia, Pennsylvania, United States of America
| | - Xiaoyan Yin
- University of Pennsylvania, Perelman School of Medicine, Institute for Diabetes, Obesity and Metabolism, Philadelphia, Pennsylvania, United States of America
| | - Rexford S. Ahima
- University of Pennsylvania, Perelman School of Medicine, Institute for Diabetes, Obesity and Metabolism, Philadelphia, Pennsylvania, United States of America
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Endogenous fructose production and metabolism in the liver contributes to the development of metabolic syndrome. Nat Commun 2014; 4:2434. [PMID: 24022321 PMCID: PMC3833672 DOI: 10.1038/ncomms3434] [Citation(s) in RCA: 171] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 08/13/2013] [Indexed: 12/12/2022] Open
Abstract
Carbohydrates with high glycemic index are proposed to promote the development of obesity, insulin resistance and fatty liver, but the mechanism by which this occurs remains unknown. High serum glucose concentrations glucose are known to induce the polyol pathway and increase fructose generation in the liver. Here we show that this hepatic, endogenously-produced fructose causes systemic metabolic changes. We demonstrate that mice unable to metabolize fructose are protected from an increase in energy intake and body weight, visceral obesity, fatty liver, elevated insulin levels and hyperleptinemia after exposure to 10% glucose for 14 weeks. In normal mice, glucose consumption is accompanied by aldose reductase and polyol pathway activation in steatotic areas. In this regard, we show that aldose reductase deficient mice were protected against glucose-induced fatty liver. We conclude that endogenous fructose generation and metabolism in the liver represents an important mechanism whereby glucose promotes the development of metabolic syndrome.
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Pawella LM, Hashani M, Eiteneuer E, Renner M, Bartenschlager R, Schirmacher P, Straub BK. Perilipin discerns chronic from acute hepatocellular steatosis. J Hepatol 2014; 60:633-42. [PMID: 24269473 DOI: 10.1016/j.jhep.2013.11.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 11/06/2013] [Accepted: 11/11/2013] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Hepatocellular steatosis is the most frequent liver disease in the western world and may develop further to steatohepatitis, liver cirrhosis and hepatocellular carcinoma. We have previously shown that lipid droplet (LD)-associated proteins of the perilipin/PAT-family are differentially expressed in hepatocyte steatosis and that perilipin is expressed de novo. The aim of this study was to determine the conditions for the temporal regulation of de novo synthesis of perilipin in vitro and in vivo. METHODS Immunohistochemical PAT-analysis was performed with over 120 liver biopsies of different etiology and duration of steatosis. Steatosis was induced in cultured hepatocytic cells with combinations of lipids, steatogenic substances and DMSO for up to 40 days under conditions of stable down-regulation of adipophilin and/or TIP47. RESULTS Whereas perilipin and adipophilin were expressed in human chronic liver disease irrespective of the underlying etiology, in acute/microvesicular steatosis TIP47, and MLDP were recruited from the cytoplasm to LDs, adipophilin was strongly increased, but perilipin was virtually absent. In long-term steatosis models in vitro, TIP47, MLDP, adipophilin, and finally perilipin were gradually induced. Perilipin and associated formation of LDs were intricately regulated on the transcriptional (PPARs, C/EBPs, SREBP), post-transcriptional, and post-translational level (TAG-amount, LD-fusion, phosphorylation-dependent lipolysis). In long-term steatosis models under stable down-regulation of adipophilin and/or TIP47, MLDP substituted for TIP47, and perilipin for adipophilin. CONCLUSIONS LD-maturation in hepatocytes in vivo and in vitro involves sequential expression of TIP47, MLDP, adipophilin and finally perilipin. Thus, perilipin might be used for the differential diagnosis of chronic vs. acute steatosis.
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Affiliation(s)
- Lena Maria Pawella
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany
| | - Merita Hashani
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany
| | - Eva Eiteneuer
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany
| | - Marcus Renner
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany
| | - Ralf Bartenschlager
- Department for Infectious Diseases, Molecular Virology, Im Neuenheimer Feld 345, D-69120 Heidelberg, Germany
| | - Peter Schirmacher
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany
| | - Beate Katharina Straub
- Department of General Pathology, Institute of Pathology, Im Neuenheimer Feld 224, D-69120 Heidelberg, Germany.
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Shearn CT, Smathers RL, Backos DS, Reigan P, Orlicky DJ, Petersen DR. Increased carbonylation of the lipid phosphatase PTEN contributes to Akt2 activation in a murine model of early alcohol-induced steatosis. Free Radic Biol Med 2013; 65:680-692. [PMID: 23872024 PMCID: PMC3859727 DOI: 10.1016/j.freeradbiomed.2013.07.011] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 06/25/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
The production of reactive aldehydes such as 4-hydroxynonenal (4-HNE) is a key event in the pathogenesis of alcoholic liver disease (ALD), which ranges from simple steatosis to fibrosis. The lipid phosphatase PTEN plays a central role in the regulation of lipid metabolism in the liver. In this study, the effects of chronic ethanol feeding and carbonylation on the PTEN signaling pathway were examined in a 9-week mouse feeding model for ALD. Chronic ethanol consumption resulted in altered redox homeostasis as evidenced by decreased GSH, decreased Trx1, and increased GST activity. Both PTEN expression and PTEN phosphorylation were significantly increased in the livers of ethanol-fed mice. Carbonylation of PTEN increased significantly in the ethanol-fed mice compared to pair-fed control animals, corresponding to decreased PTEN 3-phosphatase activity. Concomitantly, increased expression of Akt2 along with increased Akt phosphorylation at residues Thr(308), Thr(450), and Ser(473) was observed resulting in increased Akt2 activity in the ethanol-fed animals. Akt2 activation corresponded to a decrease in cytosolic SREBP and ChREBP. Subsequent LC/MS/MS analysis of 4-HNE-modified recombinant human PTEN identified Michael addition adducts of 4-HNE on Cys(71), Cys(136), Lys(147), Lys(223), Cys(250), Lys(254), Lys(313), Lys(327), and Lys(344). Computational-based molecular modeling analysis of 4-HNE adducted to Cys(71) near the active site and Lys(327) in the C2 domain of PTEN suggested inhibition of enzyme catalysis via either stearic hindrance of the active-site pocket or prevention of C2 domain-dependent PTEN function. We hypothesize that 4-HNE-mediated PTEN inhibition contributes to the observed activation of Akt2, suggesting a possible novel mechanism of lipid accumulation in response to increased reactive aldehyde production during chronic ethanol administration in mice.
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Affiliation(s)
- C T Shearn
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - R L Smathers
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D S Backos
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - P Reigan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - D J Orlicky
- Department of Pathology, School of Medicine, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Dennis R Petersen
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver, Anschutz Medical Campus, Aurora, CO 80045, USA.
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Ishimoto T, Lanaspa MA, Rivard CJ, Roncal-Jimenez CA, Orlicky DJ, Cicerchi C, McMahan RH, Abdelmalek MF, Rosen HR, Jackman MR, MacLean PS, Diggle CP, Asipu A, Inaba S, Kosugi T, Sato W, Maruyama S, Sánchez-Lozada LG, Sautin YY, Hill JO, Bonthron DT, Johnson RJ. High-fat and high-sucrose (western) diet induces steatohepatitis that is dependent on fructokinase. Hepatology 2013; 58:1632-43. [PMID: 23813872 PMCID: PMC3894259 DOI: 10.1002/hep.26594] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/01/2013] [Accepted: 06/17/2013] [Indexed: 12/13/2022]
Abstract
UNLABELLED Fructose intake from added sugars has been implicated as a cause of nonalcoholic fatty liver disease. Here we tested the hypothesis that fructose may interact with a high-fat diet to induce fatty liver, and to determine if this was dependent on a key enzyme in fructose metabolism, fructokinase. Wild-type or fructokinase knockout mice were fed a low-fat (11%), high-fat (36%), or high-fat (36%) and high-sucrose (30%) diet for 15 weeks. Both wild-type and fructokinase knockout mice developed obesity with mild hepatic steatosis and no evidence of hepatic inflammation on a high-fat diet compared to a low-fat diet. In contrast, wild-type mice fed a high-fat and high-sucrose diet developed more severe hepatic steatosis with low-grade inflammation and fibrosis, as noted by increased CD68, tumor necrosis factor alpha, monocyte chemoattractant protein-1, alpha-smooth muscle actin, and collagen I and TIMP1 expression. These changes were prevented in the fructokinase knockout mice. CONCLUSION An additive effect of high-fat and high-sucrose diet on the development of hepatic steatosis exists. Further, the combination of sucrose with high-fat diet may induce steatohepatitis. The protection in fructokinase knockout mice suggests a key role for fructose (from sucrose) in this development of steatohepatitis. These studies emphasize the important role of fructose in the development of fatty liver and nonalcoholic steatohepatitis.
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Affiliation(s)
- Takuji Ishimoto
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Miguel A. Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Christopher J. Rivard
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Carlos A. Roncal-Jimenez
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - David J. Orlicky
- Department of Pathology, University of Colorado Denver, Aurora, CO 80045, USA
| | - Christina Cicerchi
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Rachel H. McMahan
- Division of Gastroenterology and Hepatology, University of Colorado Denver, Denver, CO, 80045, USA
| | | | - Hugo R. Rosen
- Division of Gastroenterology and Hepatology, University of Colorado Denver, Denver, CO, 80045, USA
| | - Matthew R. Jackman
- Division of Endocrinology, Colorado Nutrition Obesity Research Center, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Paul S. MacLean
- Division of Endocrinology, Colorado Nutrition Obesity Research Center, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Christine P. Diggle
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Aruna Asipu
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Shinichiro Inaba
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Tomoki Kosugi
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA
| | - Waichi Sato
- Departments of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Shoichi Maruyama
- Departments of Nephrology, Nagoya University Graduate School of Medicine, Nagoya, 466-8550, Japan
| | - Laura G. Sánchez-Lozada
- Lab. of Renal Physiopathology & Dept. of Nephrology. INC Ignacio Chavez, Mexico City, 14080, Mexico
| | - Yuri Y. Sautin
- Division of Nephrology and Hypertension, University of Florida, Gainesville, FL, 32610, USA
| | - James O. Hill
- Anschutz Health and Wellness Center, University of Colorado Denver, Aurora, CO, 80045, USA
| | - David T. Bonthron
- Leeds Institute of Molecular Medicine, University of Leeds, Leeds, LS9 7TF, UK
| | - Richard J. Johnson
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO, 80045, USA,Division of Nephrology and Hypertension, University of Florida, Gainesville, FL, 32610, USA,Address correspondence and reprint requests to Richard J Johnson, M.D.. Current address: University of Colorado Denver, Division of Renal Diseases and Hypertension, Box C281, 12700 E 19th Ave, Research 2 Room P15-7006, Aurora, CO, 80045, USA. Tel: 303 724 4898 Fax: 303 724 4831.
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Cassidy LL, Dlugos FF, Dlugos CA. Time course of SERCA 2b and calreticulin expression in Purkinje neurons of ethanol-fed rats with behavioral correlates. Alcohol Alcohol 2013; 48:667-78. [PMID: 23884168 PMCID: PMC3799558 DOI: 10.1093/alcalc/agt062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Chronic ethanol consumption for 40 weeks in adult rats results in dilation of the extensive smooth endoplasmic reticulum (SER), a major component of the calcium homeostatic system within Purkinje neuron (PN) dendrites. AIMS The aim of the present study was to determine whether chronic ethanol consumption results in alterations of the sarco/endoplasmic reticulum Ca(2+) ATPase pump (SERCA) on the SER membrane of PN dendrites. The density of calreticulin, a calcium chaperone, was also investigated in the PN along with balancing ability. METHODS Ninety 8-month-old rats were exposed to rat chow, the AIN-93 M liquid control or ethanol diets (30/diet) for a duration of 10, 20 or 40 weeks (30/duration). Age changes relative to the rat chow controls were assessed with 3-month-old control rats (n = 10). Balance was assessed prior to euthanasia. Quantitative immunocytochemistry was used to determine the density of SERCA 2b + dendrites and calreticulin + PN soma and nuclei. Molecular layer volumes were also determined. RESULTS Following 40 weeks of ethanol treatment, there were ethanol-induced decreases in SERCA 2b densities within the dendritic arbor and decreased balancing ability on the more difficult round rod balance test. There were no ethanol-induced changes in calreticulin densities. CONCLUSION It can be concluded that ethanol-induced decreases in the SERCA pump accompany SER dilation and contribute to previously reported ethanol-induced dendritic regression in PN. Ethanol-induced changes in balance also occurred. Chronic ethanol consumption does not alter calreticulin expression in PN.
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Affiliation(s)
- Linda L Cassidy
- Corresponding author: Department of Pathology and Anatomical Sciences, 206 Farber Hall, School of Medicine and Biomedical Sciences, Main Street, Buffalo, NY 14214, USA
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Crunk AE, Monks J, Murakami A, Jackman M, MacLean PS, Ladinsky M, Bales ES, Cain S, Orlicky DJ, McManaman JL. Dynamic regulation of hepatic lipid droplet properties by diet. PLoS One 2013; 8:e67631. [PMID: 23874434 PMCID: PMC3708958 DOI: 10.1371/journal.pone.0067631] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 05/20/2013] [Indexed: 12/21/2022] Open
Abstract
Cytoplasmic lipid droplets (CLD) are organelle-like structures that function in neutral lipid storage, transport and metabolism through the actions of specific surface-associated proteins. Although diet and metabolism influence hepatic CLD levels, how they affect CLD protein composition is largely unknown. We used non-biased, shotgun, proteomics in combination with metabolic analysis, quantitative immunoblotting, electron microscopy and confocal imaging to define the effects of low- and high-fat diets on CLD properties in fasted-refed mice. We found that the hepatic CLD proteome is distinct from that of CLD from other mammalian tissues, containing enzymes from multiple metabolic pathways. The hepatic CLD proteome is also differentially affected by dietary fat content and hepatic metabolic status. High fat feeding markedly increased the CLD surface density of perilipin-2, a critical regulator of hepatic neutral lipid storage, whereas it reduced CLD levels of betaine-homocysteine S-methyltransferase, an enzyme regulator of homocysteine levels linked to fatty liver disease and hepatocellular carcinoma. Collectively our data demonstrate that the hepatic CLD proteome is enriched in metabolic enzymes, and that it is qualitatively and quantitatively regulated by diet and metabolism. These findings implicate CLD in the regulation of hepatic metabolic processes, and suggest that their properties undergo reorganization in response to hepatic metabolic demands.
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Affiliation(s)
- Amanda E. Crunk
- Graduate Program of Molecular Biology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Jenifer Monks
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Aya Murakami
- Graduate Program of Molecular Biology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Matthew Jackman
- Division of Endocrinology and Metabolism, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Center for Human Nutrition, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Colorado Obesity Research Initiative, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Paul S. MacLean
- Division of Endocrinology and Metabolism, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Center for Human Nutrition, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Colorado Obesity Research Initiative, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Mark Ladinsky
- The Boulder Laboratory for 3D Electron Microscopy, University of Colorado Boulder, Boulder Colorado, United States of America
| | - Elise S. Bales
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Shannon Cain
- The Colorado Obesity Research Initiative, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - David J. Orlicky
- Department of Pathology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - James L. McManaman
- Graduate Program of Molecular Biology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Center for Human Nutrition, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- The Colorado Obesity Research Initiative, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- * E-mail:
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Orlicky DJ, Monks J, Stefanski AL, McManaman JL. Dynamics and molecular determinants of cytoplasmic lipid droplet clustering and dispersion. PLoS One 2013; 8:e66837. [PMID: 23825572 PMCID: PMC3692517 DOI: 10.1371/journal.pone.0066837] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Accepted: 05/12/2013] [Indexed: 11/18/2022] Open
Abstract
Perilipin-1 (Plin1), a prominent cytoplasmic lipid droplet (CLD) binding phosphoprotein and key physiological regulator of triglyceride storage and lipolysis in adipocytes, is thought to regulate the fragmentation and dispersion of CLD that occurs in response to β-adrenergic activation of adenylate cyclase. Here we investigate the dynamics and molecular determinants of these processes using cell lines stably expressing recombinant forms of Plin1 and/or other members of the perilipin family. Plin1 and a C-terminal CLD-binding fragment of Plin1 (Plin1CT) induced formation of single dense CLD clusters near the microtubule organizing center, whereas neither an N-terminal CLD-binding fragment of Plin1, nor Plin2 or Plin3 induced clustering. Clustered CLD coated by Plin1, or Plin1CT, dispersed in response to isoproterenol, or other agents that activate adenylate cyclase, in a process inhibited by the protein kinase A inhibitor, H89, and blocked by microtubule disruption. Isoproterenol-stimulated phosphorylation of CLD-associated Plin1 on serine 492 preceded their dispersion, and live cell imaging showed that cluster dispersion involved initial fragmentation of tight clusters into multiple smaller clusters, which then fragmented into well-dispersed individual CLD. siRNA knockdown of the cortical actin binding protein, moesin, induced disaggregation of tight clusters into multiple smaller clusters, and inhibited the reaggregation of dispersed CLD into tight clusters. Together these data suggest that the clustering and dispersion processes involve a complex orchestration of phosphorylation-dependent, microtubule-dependent and independent, and microfilament dependent steps.
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Affiliation(s)
- David J. Orlicky
- Department of Pathology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Jenifer Monks
- Division of Basic Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - Adrianne L. Stefanski
- Division of Basic Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Graduate Program in Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
| | - James L. McManaman
- Division of Basic Reproductive Sciences, Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- Graduate Program in Reproductive Sciences, University of Colorado School of Medicine, Aurora, Colorado, United States of America
- * E-mail:
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Increased dietary fat contributes to dysregulation of the LKB1/AMPK pathway and increased damage in a mouse model of early-stage ethanol-mediated steatosis. J Nutr Biochem 2013; 24:1436-45. [PMID: 23465594 DOI: 10.1016/j.jnutbio.2012.12.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 11/30/2012] [Accepted: 12/06/2012] [Indexed: 12/22/2022]
Abstract
OBJECTIVE The objective of the study was to examine the interaction of moderate and high dietary fat and ethanol with respect to formation of steatosis and regulation of the AMP-activated protein kinase (AMPK) pathway in a mouse model of chronic ethanol consumption. METHODS Male C57BL/6J mice were pair-fed a modified Lieber-DeCarli diet composed of either moderate fat [30% fat-derived calories (MF)] or high fat [45% fat-derived calories (HF)] combined with increasing concentrations of ethanol (2%-6%) for 6 weeks. RESULTS Chronic ethanol consumption resulted in significant increases in plasma alanine aminotransferase in MF (1.84-fold) and HF mice (2.33-fold), yet liver triglycerides only increased significantly in the HF model (1.62-fold). Ethanol addition significantly increased plasma adiponectin under conditions of MF but not HF. In combination with MF, the addition of ethanol significantly decreased total and hepatic pThr(172)AMPKα and acetyl CoA Carboxylase (ACC). HF plus ethanol decreased pSer(108)AMPKβ, yet a marked 1.5-fold increase in pThr(172)AMPKα occurred. No change was evident in pSer(79)ACC under conditions of ethanol and HF ingestion. In both models, nuclear levels of sterol response element binding protein 1c and carbohydrate response element binding protein were decreased. Surprisingly, MF plus ethanol significantly elevated protein expression of medium-chain acyl-CoA dehydrogenase (MCAD), long-chain acyl-CoA dehydrogenase (LCAD) and very long chain acyl-CoA dehydrogenase but did not significantly affect mRNA expression of other proteins involved in β-oxidation and fatty acid synthesis. HF plus ethanol significantly reduced mRNA expression of both stearoyl CoA desaturase 1 and fatty acid elongase 5, but did not have an effect on MCAD or LCAD. CONCLUSION These data suggest that, when co-ingested with ethanol, dietary fat differentially contributes to dysregulation of adiponectin-dependent activation of the AMPK pathway in the liver of mice.
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McManaman JL, Bales ES, Orlicky DJ, Jackman M, MacLean PS, Cain S, Crunk AE, Mansur A, Graham CE, Bowman TA, Greenberg AS. Perilipin-2-null mice are protected against diet-induced obesity, adipose inflammation, and fatty liver disease. J Lipid Res 2013; 54:1346-59. [PMID: 23402988 DOI: 10.1194/jlr.m035063] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The cytoplasmic lipid droplet (CLD) protein perilipin-2 (Plin2) is expressed in multiple nonadipose tissues, where it is thought to play a role in regulating their lipid storage properties. However, the extent to which Plin2 functions in nutrient utilization and metabolism, or how it influences the consequences of over-feeding, remains unclear. In this study, we demonstrate that the absence of Plin2 prevents high-fat diet(HFD)-induced obesity in male and female mice. This response is associated with increased formation of subcutaneous beige adipocyte cells with uncoupling protein 1 expression, and amelioration of inflammatory foci formation in white adipose tissue and steatosis in the liver. Experiments demonstrate that Plin2 loss results in reduced energy intake and increased physical activity in response to HFD feeding. Our study provides the first evidence that Plin2 contributes to HFD-induced obesity by modulating food intake, and that its absence prevents obesity-associated adipose tissue inflammatory foci and liver steatosis.
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Affiliation(s)
- James L McManaman
- Division of Basic Reproductive Sciences, University of Colorado School of Medicine, Aurora, CO, USA.
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Carr RM, Dhir R, Yin X, Agarwal B, Ahima RS. Temporal effects of ethanol consumption on energy homeostasis, hepatic steatosis, and insulin sensitivity in mice. Alcohol Clin Exp Res 2013; 37:1091-9. [PMID: 23398239 DOI: 10.1111/acer.12075] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/20/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND Alcoholic liver disease (ALD) progresses from steatosis to inflammation, fibrosis, and cirrhosis. Although ALD has been associated with insulin resistance, it is unclear whether insulin resistance coincides with the development of steatosis. METHODS We studied the temporal relationship of steatosis and glucose homeostasis in mice fed a Lieber-DeCarli liquid control or ethanol (EtOH) diet for 2, 4, or 8 weeks. We studied the effects of alcohol consumption on energy balance, body composition, and hepatic lipids. Glucose tolerance test was performed, and insulin sensitivity was evaluated with hyperinsulinemic-euglycemic clamp. RESULTS EtOH-fed mice developed hepatic steatosis over time as compared with control-fed mice despite similar energy intake and expenditure, and gain in body weight and fat. EtOH-fed mice developed glucose intolerance as early as 2 weeks, while insulin resistance developed at 4 weeks. A hyperinsulinemic clamp study at 8 weeks revealed both hepatic and peripheral insulin resistance in EtOH-fed mice. Insulin resistance was associated with hepatic steatosis, increased ceramide levels, and Perilipin 2 expression. CONCLUSIONS Chronic EtOH consumption leads to the development of hepatic steatosis, impaired glucose tolerance, and insulin resistance. These changes are independent of energy intake or expenditure, weight, whole body fat content, and inflammation. A better understanding of the processes linking EtOH-induced steatosis and abnormal glucose homeostasis may lead to novel therapies targeting the progression of ALD.
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Affiliation(s)
- Rotonya M Carr
- Department of Medicine, Gastroenterology Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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Ronis MJJ, Baumgardner JN, Marecki JC, Hennings L, Wu X, Shankar K, Cleves MA, Gomez-Acevedo H, Badger TM. Dietary fat source alters hepatic gene expression profile and determines the type of liver pathology in rats overfed via total enteral nutrition. Physiol Genomics 2012; 44:1073-89. [PMID: 22991207 DOI: 10.1152/physiolgenomics.00069.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
To determine if dietary fat composition affects the progression of nonalcoholic fatty liver disease (NAFLD), we overfed male Sprague-Dawley rats low (5%) or high (70%) fat diets with different fat sources: olive oil (OO), corn oil (CO), or echium oil (EO), with total enteral nutrition (TEN) for 21 days. Overfeeding of the 5% CO or 5% EO diets resulted in less steatosis than 5% OO (P < 0.05). Affymetrix array analysis revealed significant differences in hepatic gene expression signatures associated with greater fatty acid synthesis, ChREBP, and SREBP-1c signaling and increased fatty acid transport (P < 0.05) in the 5% OO compared with 5% CO group. The OO groups had macrosteatosis, but no evidence of oxidative stress or necrosis. The 70% CO and 70% EO groups had a mixture of micro- and macrosteatosis or only microsteatosis, respectively; increased oxidative stress; and increased necrotic injury relative to their respective 5% groups (P < 0.05). Oxidative stress and necrosis correlated with increasing peroxidizability of the accumulated triglycerides. Affymetrix array analysis comparing the 70% OO and 70% CO groups revealed increased antioxidant pathways and lower expression of genes linked to inflammation and fibrosis in the 70% OO group. A second study in which 70% OO diet was overfed for 50 days produced no evidence of progression of injury beyond simple steatosis. These data suggest that dietary fat type strongly influences the progression of NAFLD and that a Mediterranean diet high in olive oil may reduce the risk of NAFLD progressing to nonalcoholic steatohepatitis.
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Affiliation(s)
- M J J Ronis
- Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72202, USA.
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Murphy DJ. The dynamic roles of intracellular lipid droplets: from archaea to mammals. PROTOPLASMA 2012; 249:541-85. [PMID: 22002710 DOI: 10.1007/s00709-011-0329-7] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 09/28/2011] [Indexed: 05/02/2023]
Abstract
During the past decade, there has been a paradigm shift in our understanding of the roles of intracellular lipid droplets (LDs). New genetic, biochemical and imaging technologies have underpinned these advances, which are revealing much new information about these dynamic organelles. This review takes a comparative approach by examining recent work on LDs across the whole range of biological organisms from archaea and bacteria, through yeast and Drosophila to mammals, including humans. LDs probably evolved originally in microorganisms as temporary stores of excess dietary lipid that was surplus to the immediate requirements of membrane formation/turnover. LDs then acquired roles as long-term carbon stores that enabled organisms to survive episodic lack of nutrients. In multicellular organisms, LDs went on to acquire numerous additional roles including cell- and organism-level lipid homeostasis, protein sequestration, membrane trafficking and signalling. Many pathogens of plants and animals subvert their host LD metabolism as part of their infection process. Finally, malfunctions in LDs and associated proteins are implicated in several degenerative diseases of modern humans, among the most serious of which is the increasingly prevalent constellation of pathologies, such as obesity and insulin resistance, which is associated with metabolic syndrome.
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Affiliation(s)
- Denis J Murphy
- Division of Biological Sciences, University of Glamorgan, Cardiff, CF37 4AT, UK.
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44
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Jin M, Kumar A, Kumar S. Ethanol-mediated regulation of cytochrome P450 2A6 expression in monocytes: role of oxidative stress-mediated PKC/MEK/Nrf2 pathway. PLoS One 2012; 7:e35505. [PMID: 22530035 PMCID: PMC3329463 DOI: 10.1371/journal.pone.0035505] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 03/16/2012] [Indexed: 11/19/2022] Open
Abstract
Cytochrome P450 2A6 (CYP2A6) is known to metabolize nicotine, the major constituent of tobacco, leading to the production of toxic metabolites and induction of oxidative stress that result in liver damage and lung cancer. Recently, we have shown that CYP2A6 is induced by ethanol and metabolizes nicotine into cotinine and other metabolites leading to generation of reactive oxygen species (ROS) in U937 monocytes. However, the mechanism by which CYP2A6 is induced by ethanol is unknown. In this study, we have examined the role of the PKC/Nrf2 pathway (protein kinase C-mediated phosphorylation and translocation of nuclear erythroid 2-related factor 2 to the nucleus) in ethanol-mediated CYP2A6 induction. Our results showed that 100 mM ethanol significantly induced CYP2A6 mRNA and protein (~150%) and increased ROS formation, and induction of gene expression and ROS were both completely blocked by treatment with either a CYP2E1 inhibitor (diallyl sulfide) or an antioxidant (vitamin C). The results suggest the role of oxidative stress in the regulation of CYP2A6 expression. Subsequently, we investigated the role of Nrf2 pathway in oxidative stress-mediated regulation of CYP2A6 expression in U937 monocytes. Our results showed that butylated hydroxyanisole, a stabilizer of nuclear Nrf2, increased CYP2A6 levels >200%. Staurosporine, an inhibitor of PKC, completely abolished ethanol-induced CYP2A6 expression. Furthermore, our results showed that a specific inhibitor of mitogen-activated protein kinase kinase (MEK) (U0126) completely abolished ethanol-mediated CYP2A6 induction and Nrf2 translocation. Overall, these results suggest that CYP2E1-mediated oxidative stress produced as a result of ethanol metabolism translocates Nrf2 into the nucleus through PKC/MEK pathway, resulting in the induction of CYP2A6 in monocytes. An increased level of CYP2A6 in monocytes is expected to further increase oxidative stress in smokers through CYP2A6-mediated nicotine metabolism. Thus, this study has clinical relevance because of the high incidence of alcohol use among smokers, especially in HIV-infected individuals.
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Affiliation(s)
- Mengyao Jin
- Division of Pharmacology and Toxicology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America.
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Lipid droplet accumulation and impaired fat efflux in polarized hepatic cells: consequences of ethanol metabolism. Int J Hepatol 2012; 2012:978136. [PMID: 22506128 PMCID: PMC3312290 DOI: 10.1155/2012/978136] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 11/22/2011] [Accepted: 12/08/2011] [Indexed: 12/20/2022] Open
Abstract
Steatosis, an early manifestation in alcoholic liver disease, is associated with the accumulation of hepatocellular lipid droplets (LDs). However, the role ethanol metabolism has in LD formation and turnover remains undefined. Here, we assessed LD dynamics following ethanol and oleic acid treatment to ethanol-metabolizing WIF-B cells (a hybrid of human fibroblasts (WI 38) and Fao rat hepatoma cells). An OA dose-dependent increase in triglyceride and stained lipids was identified which doubled (P < 0.05) in the presence of ethanol. This effect was blunted with the inclusion of an alcohol metabolism inhibitor. The ethanol/ OA combination also induced adipophilin, LD coat protein involved in the attenuation of lipolysis. Additionally, ethanol treatment resulted in a significant reduction in lipid efflux. These data demonstrate that the metabolism of ethanol in hepatic cells is related to LD accumulation, impaired fat efflux, and enhancements in LD-associated proteins. These alterations in LD dynamics may contribute to ethanol-mediated defects in hepatocellular LD regulation and the formation of steatosis.
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Greenberg AS, Coleman RA, Kraemer FB, McManaman JL, Obin MS, Puri V, Yan QW, Miyoshi H, Mashek DG. The role of lipid droplets in metabolic disease in rodents and humans. J Clin Invest 2011; 121:2102-10. [PMID: 21633178 DOI: 10.1172/jci46069] [Citation(s) in RCA: 470] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Lipid droplets (LDs) are intracellular organelles that store neutral lipids within cells. Over the last two decades there has been a dramatic growth in our understanding of LD biology and, in parallel, our understanding of the role of LDs in health and disease. In its simplest form, the LD regulates the storage and hydrolysis of neutral lipids, including triacylglycerol and/or cholesterol esters. It is becoming increasingly evident that alterations in the regulation of LD physiology and metabolism influence the risk of developing metabolic diseases such as diabetes. In this review we provide an update on the role of LD-associated proteins and LDs in metabolic disease.
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Affiliation(s)
- Andrew S Greenberg
- Obesity and Metabolism Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts 02111, USA.
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