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Yu HC, Bai QR, Guo JJ, Chen MY, Wang L, Tong FC, Zhang SL, Wu J. Elucidating hydroxysafflor yellow A's multi-target mechanisms against alcoholic liver disease through integrative pharmacology. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 134:155956. [PMID: 39216301 DOI: 10.1016/j.phymed.2024.155956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 07/09/2024] [Accepted: 08/14/2024] [Indexed: 09/04/2024]
Abstract
BACKGROUND Alcoholic liver disease (ALD) significantly contributes to global liver-related morbidity and mortality. Natural products play a crucial role in the prevention and treatment of ALD. Hydroxysafflor yellow A (HSYA), a unique and primary component of Safflower (Carthamus tinctorius l.), exhibits diverse pharmacological activities. However, the impact and mechanism of HSYA on ALD have not been fully elucidated. PURPOSE The purpose of this study was to employ an integrative pharmacology approach to assess the multi-targeted mechanism of HSYA against ALD. METHODS Network pharmacology and molecular docking techniques were used to analyze the potential therapeutic signaling pathways and targets of HSYA against ALD. An ALD model in zebrafish larvae was established. Larvae were pretreated with HSYA and then exposed to ethanol. Liver injury was measured by fluorescence expression analysis in the liver-specific transgenic zebrafish line Tg (fabp10a:DsRed) and liver tissue H&E staining. Liver steatosis was determined by whole-mount oil red O staining and TG level. Additionally, an ethanol-induced hepatocyte injury model was established in vitro to observe hepatocyte damage (cell viability, ALT level), lipid accumulation (oil red O staining, TC and TG), and oxidative stress (ROS, MDA, GPx and SOD) in HepG2 cells treated with or without HSYA. Finally, qRT-PCR combined with network pharmacology and molecular docking was employed to validate the effects of HSYA on targets. RESULTS HSYA exhibited a significant, dose-dependent improvement in ethanol-induced liver injury in zebrafish larvae and HepG2 cells. Network pharmacology analysis revealed that HSYA may exert pharmacological effects against ALD through 341 potential targets. These targets are involved in various signaling pathways, including lipid metabolism and atherosclerosis, PI3K-Akt signaling pathway, MAPK signaling pathway, and ALD itself. Molecular docking studies displayed that HSYA had a strong binding affinity toward the domains of IL1B, IL6, TNF, PPARA, PPARG, HMGCR and ADH5. qRT-PCR assays demonstrated that HSYA effectively reversed the ethanol-induced aberrant gene expression of SREBF1, FASN, ACACA, CPT1A, PPARA, IL1B, IL6, TNFα, ADH5, and ALDH2 in vivo and in vitro. CONCLUSION This study offers a comprehensive investigation into the anti-ALD mechanisms of HSYA using an integrative pharmacology approach. The potential targets of HSYA may be implicated in enhancing ethanol catabolism, reducing lipid accumulation, mitigating oxidative stress, and inhibiting inflammatory response.
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Affiliation(s)
- Hai-Chuan Yu
- School of Medical Technology, Xinxiang Medical University, NO. 601 Jinsui Avenue, Xinxiang, Henan 453003, China.
| | - Qi-Rong Bai
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Jiao-Jie Guo
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Meng-Yao Chen
- School of Medical Technology, Xinxiang Medical University, NO. 601 Jinsui Avenue, Xinxiang, Henan 453003, China
| | - Lin Wang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
| | - Fang-Chao Tong
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Shuang-Ling Zhang
- School of Medical Technology, Xinxiang Medical University, NO. 601 Jinsui Avenue, Xinxiang, Henan 453003, China
| | - Jiao Wu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, China.
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Alhaddad H, Wong W, Abou-Gharbia M, Childers W, Melenski E, Bell RL, Sari Y. Effects of a Novel Beta Lactam Compound, MC-100093, on the Expression of Glutamate Transporters/Receptors and Ethanol Drinking Behavior of Alcohol-Preferring Rats. J Pharmacol Exp Ther 2022; 383:208-216. [PMID: 36153003 PMCID: PMC9667983 DOI: 10.1124/jpet.122.001147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 09/16/2022] [Indexed: 01/07/2023] Open
Abstract
Chronic ethanol exposure affects the glutamatergic system in several brain reward regions including the nucleus accumbens (NAc). Our laboratory has shown that chronic exposure to ethanol reduced the expression of glutamate transporter 1 (GLT-1) and cystine/glutamate exchanger (xCT) and, as a result, increased extracellular glutamate concentrations in the NAc of alcohol-preferring (P) rats. Moreover, previous studies from our laboratory reported that chronic ethanol intake altered the expression of certain metabotropic glutamate receptors in the brain. In addition to central effects, chronic ethanol consumption induced liver injury, which is associated with steatohepatitis. In the present study, we investigated the effects of chronic ethanol consumption in the brain and liver. Male P rats had access to a free choice of ethanol and water bottles for five weeks. Chronic ethanol consumption reduced GLT-1 and xCT expression in the NAc shell but not in the NAc core. Furthermore, chronic ethanol consumption increased fat droplet content as well as peroxisome proliferator-activated receptor alpha (PPAR-α) and GLT-1 expression in the liver. Importantly, treatment with the novel beta-lactam compound, MC-100093, reduced ethanol drinking behavior and normalized the levels of GLT-1 and xCT expression in the NAc shell as well as normalized GLT-1 and PPAR-α expression in the liver. In addition, MC-100093 attenuated ethanol-induced increases in fat droplet content in the liver. These findings suggest that MC-100093 may be a potential lead compound to attenuate ethanol-induced dysfunction in the glutamatergic system and liver injury. SIGNIFICANCE STATEMENT: This study identified a novel beta-lactam, MC-100093, that has demonstrated upregulatory effects on GLT-1. MC-100093 reduced ethanol drinking behavior and normalized levels of GLT-1 and xCT expression in the NAc shell as well as normalized GLT-1 and PPAR-α expression in the liver. In addition, MC-100093 attenuated ethanol-induced increases in fat droplet content in the liver.
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Affiliation(s)
- Hasan Alhaddad
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Woonyen Wong
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Magid Abou-Gharbia
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Wayne Childers
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Edward Melenski
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Richard L Bell
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
| | - Youssef Sari
- University of Toledo, College of Pharmacy and Pharmaceutical Sciences, Department of Pharmacology and Experimental Therapeutics, Toledo, Ohio (H.A., W.W., Y.S.); Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, Pennsylvania (M.A-G., W.C., E.M.); and Department of Psychiatry and Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, Indiana (R.L.B.)
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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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Yeh JH, Wang KC, Kaizaki A, Lee JW, Wei HC, Tucci MA, Ojeda NB, Fan LW, Tien LT. Pioglitazone Ameliorates Lipopolysaccharide-Induced Behavioral Impairment, Brain Inflammation, White Matter Injury and Mitochondrial Dysfunction in Neonatal Rats. Int J Mol Sci 2021; 22:6306. [PMID: 34208374 PMCID: PMC8231261 DOI: 10.3390/ijms22126306] [Citation(s) in RCA: 4] [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: 04/30/2021] [Revised: 05/29/2021] [Accepted: 06/05/2021] [Indexed: 01/04/2023] Open
Abstract
Previous studies have demonstrated that pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, inhibits ischemia-induced brain injury. The present study was conducted to examine whether pioglitazone can reduce impairment of behavioral deficits mediated by inflammatory-induced brain white matter injury in neonatal rats. Intraperitoneal (i.p.) injection of lipopolysaccharide (LPS, 2 mg/kg) was administered to Sprague-Dawley rat pups on postnatal day 5 (P5), and i.p. administration of pioglitazone (20 mg/kg) or vehicle was performed 5 min after LPS injection. Sensorimotor behavioral tests were performed 24 h after LPS exposure, and changes in biochemistry of the brain was examined after these tests. The results show that systemic LPS exposure resulted in impaired sensorimotor behavioral performance, reduction of oligodendrocytes and mitochondrial activity, and increases in lipid peroxidation and brain inflammation, as indicated by the increment of interleukin-1β (IL-1β) levels and number of activated microglia in the neonatal rat brain. Pioglitazone treatment significantly improved LPS-induced neurobehavioral and physiological disturbances including the loss of body weight, hypothermia, righting reflex, wire-hanging maneuver, negative geotaxis, and hind-limb suspension in neonatal rats. The neuroprotective effect of pioglitazone against the loss of oligodendrocytes and mitochondrial activity was associated with attenuation of LPS-induced increment of thiobarbituric acid reactive substances (TBARS) content, IL-1β levels and number of activated microglia in neonatal rats. Our results show that pioglitazone prevents neurobehavioral disturbances induced by systemic LPS exposure in neonatal rats, and its neuroprotective effects are associated with its impact on microglial activation, IL-1β induction, lipid peroxidation, oligodendrocyte production and mitochondrial activity.
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Affiliation(s)
- Jiann-Horng Yeh
- Department of Neurobiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan;
- School of Medicine, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan; (K.-C.W.); (H.-C.W.)
| | - Kuo-Ching Wang
- School of Medicine, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan; (K.-C.W.); (H.-C.W.)
- Department of Anesthesiology, Shin Kong Wu Ho-Su Memorial Hospital, Taipei 111, Taiwan
| | - Asuka Kaizaki
- Department of Pharmacology, Toxicology and Therapeutics, Division of Toxicology, School of Pharmacy, Showa University, Shingawa-ku, Tokyo 142-8555, Japan;
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA; (J.W.L.); (N.B.O.); (L.-W.F.)
| | - Jonathan W. Lee
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA; (J.W.L.); (N.B.O.); (L.-W.F.)
| | - Han-Chi Wei
- School of Medicine, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan; (K.-C.W.); (H.-C.W.)
| | - Michelle A. Tucci
- Department of Anesthesiology, University of Mississippi Medical Center, Jackson, MS 39216, USA;
| | - Norma B. Ojeda
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA; (J.W.L.); (N.B.O.); (L.-W.F.)
| | - Lir-Wan Fan
- Department of Pediatrics, Division of Newborn Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA; (J.W.L.); (N.B.O.); (L.-W.F.)
| | - Lu-Tai Tien
- School of Medicine, Fu Jen Catholic University, Xinzhuang Dist., New Taipei City 24205, Taiwan; (K.-C.W.); (H.-C.W.)
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Philip S, Tom G, Balakrishnan Nair P, Sundaram S, Velikkakathu Vasumathy A. Tinospora cordifolia chloroform extract inhibits LPS-induced inflammation via NF-κB inactivation in THP-1cells and improves survival in sepsis. BMC Complement Med Ther 2021; 21:97. [PMID: 33743681 PMCID: PMC7980548 DOI: 10.1186/s12906-021-03244-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Tinospora cordifolia (Willd).Miers is a perennial climbing medicinal shrub that has been traditionally used for the treatment of chronic inflammatory ailments. Our previous pre- clinical studies on anti-inflammatory effects, proved that the chloroform extract of T. cordifolia (CETC) suppressed the LPS induced up-regulation of pro-inflammatory biomarkers, hence, further follow up study was carried out to evaluate whether CETC can exhibit a protective effect against LPS induced lethal endotoxemia in vivo and also to analyze the impact of CETC pre-treatment on the secretion of pro-inflammatory cytokines in vitro by THP-1 cells. METHODS To corroborate our previous preclinical studies on inflammation, we investigated the mechanism of the anti-inflammatory effect of T. cordifolia on THP-cells which were pre-incubated with CETC (30 min) and stimulated subsequently with LPS (1 μg/ml) for 20 h. Levels as well as gene expressions of various cytokines were compared with that of LPS alone incubated cells. Alongside, in vivo oral anti-inflammatory efficacy against LPS induced endotoxemia study was effectuated, wherein rats were administered with CETC 48, 24, 12 and 1 h prior to the injection of LPS and the survival of rats were monitored upto 10 days. Cytokine levels were quantified by ELISA. Nitrite levels were measured using Griess reagent. Expression of pro-inflammatory proteins was inspected in rat tissues by histochemical and immuno -histochemical examinations. RESULTS CETC was able to down-regulate the up-regulation of pro-inflammatory biomarkers in THP-1 macrophages though blockade of NF-κB nuclear translocation and could improve the survival rate during endotoxemic episodes with a marked suppression of the tissue expression of pro-inflammatory proteins. CONCLUSION These findings concomitantly reveal the anti-inflammatory mechanism of CETC and support us to move forward for the development of drugs against disorders resulting from deregulated immune reactions.
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Affiliation(s)
- Sheena Philip
- Plant Based Bioactives and Disease Biology Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India
- University of Kerala, Thiruvananthapuram, India
| | - Greeshma Tom
- Plant Based Bioactives and Disease Biology Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India
- University of Kerala, Thiruvananthapuram, India
| | | | - Sankar Sundaram
- Department of Pathology, Government Medical College, Kottayam, India
| | - Asha Velikkakathu Vasumathy
- Plant Based Bioactives and Disease Biology Laboratory, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, 695014, India.
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Guo FF, Xiao M, Wang SY, Zeng T, Cheng L, Xie Q. Downregulation of mitogen-activated protein kinases (MAPKs) in chronic ethanol-induced fatty liver. Toxicol Mech Methods 2020; 30:407-416. [PMID: 32237978 DOI: 10.1080/15376516.2020.1747126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) are versatile proteins that have been suggested to be involved in the regulation of lipid metabolism. This study was designed to investigate the responses of MAPK signaling to chronic ethanol exposure in vivo and in vitro, and try to explore its role in the pathogenesis of alcoholic fatty liver (AFL). Mice were fed with Lieber-Decarli liquid diet (5% ethanol, w/v) for 4 weeks to induce fatty liver, and the chronological changes of MAPK phosphorylation were measured using western blotting. We found that chronic ethanol feeding led to accumulation of triglyceride (TG), decreased phosphorylation of MAPKs, decreased protein level of peroxisomal proliferator activation receptor α (PPARα), and increased protein expression of cytochrome P4502E1 (CYP2E1) in mice liver. In vitro study showed that overexpression of CYP2E1 blunted the response of MAPKs to ethanol, and MAPK phosphatase 1 (MKP-1) knockdown by siRNA led to upregulation of PPARα protein level. Lastly, epidermal growth factor (EGF), a well-known MAPK activator, significantly suppressed chronic ethanol-induced hepatic fat accumulation and decline of PPARα expression in mice liver. Collectively, MAPK suppression, possibly due to the activation of hepatic CYP2E1, may be involved in chronic ethanol-induced hepatic steatosis.
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Affiliation(s)
- Fang-Fang Guo
- Department of Pharmacy, Qilu Hospital of Shandong University, Jinan, China
| | - Mo Xiao
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, China
| | - Shao-Yi Wang
- Department of Orthopaedic Surgery, Qilu Hospital of Shandong University, Jinan, China
| | - Tao Zeng
- Institute of Toxicology, School of Public Health, Shandong University, Jinan, China
| | - Lei Cheng
- Department of Orthopaedic Surgery, Qilu Hospital of Shandong University, Jinan, China
| | - Qing Xie
- Department of Pharmacy, Qilu Hospital of Shandong University, Jinan, China
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Jeon S, Carr R. Alcohol effects on hepatic lipid metabolism. J Lipid Res 2020; 61:470-479. [PMID: 32029510 DOI: 10.1194/jlr.r119000547] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/28/2020] [Indexed: 12/16/2022] Open
Abstract
Alcoholic liver disease (ALD) is the most prevalent type of chronic liver disease with significant morbidity and mortality worldwide. ALD begins with simple hepatic steatosis and progresses to alcoholic steatohepatitis, fibrosis, and cirrhosis. The severity of hepatic steatosis is highly associated with the development of later stages of ALD. This review explores the disturbances of alcohol-induced hepatic lipid metabolism through altered hepatic lipid uptake, de novo lipid synthesis, fatty acid oxidation, hepatic lipid export, and lipid droplet formation and catabolism. In addition, we review emerging data on the contributions of genetics and bioactive lipid metabolism in alcohol-induced hepatic lipid accumulation.
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Affiliation(s)
- Sookyoung Jeon
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
| | - Rotonya Carr
- Division of Gastroenterology, University of Pennsylvania, Philadelphia, PA
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Semen Cuscutae Administration Improves Hepatic Lipid Metabolism and Adiposity in High Fat Diet-Induced Obese Mice. Nutrients 2019; 11:nu11123035. [PMID: 31842363 PMCID: PMC6950589 DOI: 10.3390/nu11123035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/05/2019] [Accepted: 12/10/2019] [Indexed: 12/29/2022] Open
Abstract
Since arginase has been shown to compete with nitric oxide (NO) synthase, emerging evidence has reported that arginase inhibition improves obesity by increasing NO production. Semen cuscutae (SC), which is a well-known Chinese medicine, has multiple biological functions such as anti-oxidant function and immune regulation. In this study, we investigated whether the SC as a natural arginase inhibitor influences hepatic lipid abnormalities and whole-body adiposity in high-fat diet (HFD)-induced obese mice. The lipid accumulation was significantly reduced by SC treatment in oleic acid-induced hepatic steatosis in vitro. Additionally, SC supplementation substantially lowered HFD-induced increases in arginase activity and weights of liver and visceral fat tissue, while increasing hepatic NO. Furthermore, elevated mRNA expressions of sterol regulatory element-binding transcription factor 1 (SREBP-1c), fatty-acid synthase (FAS), peroxisome proliferator-activated receptor-gamma (PPAR-γ)1, and PPAR-γ2 in HFD-fed mice were significantly attenuated by SC supplementation. Taken together, SC, as a novel natural arginase inhibitor, showed anti-obesity properties by modulating hepatic arginase and NO production and metabolic pathways related to hepatic triglyceride (TG) metabolism.
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Abstract
Hepatic lipid metabolism is a series of complex processes that control influx and efflux of not only hepatic lipid pools, but also organismal pools. Lipid homeostasis is usually tightly controlled by expression, substrate supply, oxidation and secretion that keep hepatic lipid pools relatively constant. However, perturbations of any of these processes can lead to lipid accumulation in the liver. Although it is thought that these responses are hepatic arms of the 'thrifty genome', they are maladaptive in the context of chronic fatty liver diseases. Ethanol is likely unique among toxins, in that it perturbs almost all aspects of hepatic lipid metabolism. This complex response is due in part to the large metabolic demand placed on the organ by alcohol metabolism, but also appears to involve more nuanced changes in expression and substrate supply. The net effect is that steatosis is a rapid response to alcohol abuse. Although transient steatosis is largely an inert pathology, the chronicity of alcohol-related liver disease seems to require steatosis. Better and more specific understanding of the mechanisms by which alcohol causes steatosis may therefore translate into targeted therapies to treat alcohol-related liver disease and/or prevent its progression.
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Cheng CF, Pan TM. Monascus-fermented red mold dioscorea protects mice against alcohol-induced liver injury, whereas its metabolites ankaflavin and monascin regulate ethanol-induced peroxisome proliferator-activated receptor-γ and sterol regulatory element-binding transcription factor-1 expression in HepG2 cells. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:1889-1898. [PMID: 28902410 DOI: 10.1002/jsfa.8670] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 09/04/2017] [Accepted: 09/05/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Alcoholic hepatitis is a necroinflammatory process that is associated with fibrosis and leads to cirrhosis in 40% of cases. The hepatoprotective effects of red mold dioscorea (RMD) from Monascus purpureus NTU 568 were evaluated in vivo using a mouse model of chronic alcohol-induced liver disease (ALD). RESULTS ALD mice were orally administered vehicle (ALD group) or vehicle plus 307.5, 615.0 or 1537.5 mg kg-1 (1 ×, 2 × and 5 ×) RMD for 5 weeks. RMD lowered serum leptin, hepatic total cholesterol, free fatty acid and hepatic triglyceride levels and increased serum adiponectin, hepatic alcohol dehydrogenase and antioxidant enzyme levels. Furthermore, ankaflavin (AK) and monascin (MS), metabolites of RMD fermented with M. purpureus 568, induced peroxisome proliferator-activated receptor-γ expression and the concomitant suppression of ethanol-induced elevation of sterol regulatory element-binding transcription factor-1 and TG in HepG2 cells. CONCLUSION These results indicate the hepatoprotective effect of Monascus-fermented RMD. Moreover, AK and MS were identified as the active constituents of RMD for the first time and were shown to protect against ethanol-induced liver damage. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Chih-Fu Cheng
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Tzu-Ming Pan
- Department of Biochemical Science and Technology, College of Life Science, National Taiwan University, Taipei, Taiwan
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Meng YK, Li CY, Li RY, He LZ, Cui HR, Yin P, Zhang CE, Li PY, Sang XX, Wang Y, Niu M, Zhang YM, Guo YM, Sun R, Wang JB, Bai ZF, Xiao XH. Cis-stilbene glucoside in Polygonum multiflorum induces immunological idiosyncratic hepatotoxicity in LPS-treated rats by suppressing PPAR-γ. Acta Pharmacol Sin 2017. [PMID: 28649126 DOI: 10.1038/aps.2017.32] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The root of Polygonum multiflorum Thunb (PM) has been used in China to treat a variety of diseases, such as constipation, early graying of the hair and hyperlipemia. Recent evidence shows that PM causes idiosyncratic drug-induced liver injury (IDILI) in humans. In this study, we investigated the molecular basis of PM-induced liver injury in a rat model of IDILI based on a non-hepatotoxic dose of LPS. SD rats were orally administered 3 potentially hepatotoxic compounds of PM: cis-stilbene glucoside (cis-SG, 50 mg/kg), trans-SG (50 mg/kg) or emodin (5 mg/kg), followed by injection of LPS (2.8 mg/kg, iv). Serum and liver histology were evaluated 7 h after LPS injection. Among the 3 compounds tested, cis-SG, but not emodin or trans-SG, induced severe liver injury in rats when combined with LPS. The levels of AST and ALT in plasma and inflammatory cytokines in both plasma and liver tissues were markedly elevated. The liver tissues showed increased injury, hepatocyte apoptosis, and macrophage infiltration, and decreased cell proliferation. Microarray analysis revealed a negative correlation between peroxisome proliferator-activated receptor-γ (PPAR-γ) and LPS/cis-SG-induced liver injury. Immunohistochemical staining and RT-PCR results further confirmed that cis-SG significantly inhibited activation of the PPAR-γ pathway in the liver tissues of LPS/cis-SG-treated rats. Pre-treatment with a PPAR-γ agonist pioglitazone (500 g/kg, ig) reversed LPS/cis-SG-induced liver injury, which was associated with inhibiting the nuclear factor kappa B (NF-κB) pathway. These data demonstrate that cis-stilbene glucoside induces immunological idiosyncratic hepatotoxicity through suppressing PPAR-γ in a rat model of IDILI.
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Zeng T, Zhang CL, Zhao N, Guan MJ, Xiao M, Yang R, Zhao XL, Yu LH, Zhu ZP, Xie KQ. Impairment of Akt activity by CYP2E1 mediated oxidative stress is involved in chronic ethanol-induced fatty liver. Redox Biol 2017; 14:295-304. [PMID: 28987868 PMCID: PMC5633250 DOI: 10.1016/j.redox.2017.09.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 09/24/2017] [Indexed: 12/30/2022] Open
Abstract
Protein kinase B (PKB/Akt) plays important roles in the regulation of lipid homeostasis, and impairment of Akt activity has been demonstrated to be involved in the development of non-alcoholic fatty liver disease (NAFLD). Previous studies suggest that cytochrome P4502E1 (CYP2E1) plays causal roles in the pathogenesis of alcoholic fatty liver (AFL). We hypothesized that Akt activity might be impaired due to CYP2E1-induced oxidative stress in chronic ethanol-induced hepatic steatosis. In this study, we found that chronic ethanol-induced hepatic steatosis was accompanied with reduced phosphorylation of Akt at Thr308 in mice liver. Chronic ethanol exposure had no effects on the protein levels of phosphatidylinositol 3 kinase (PI3K) and phosphatase and tensin homologue deleted on chromosome ten (PTEN), and led to a slight decrease of phosphoinositide-dependent protein kinase 1 (PDK-1) protein level. Ethanol exposure resulted in increased levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE)-Akt adducts, which was significantly inhibited by chlormethiazole (CMZ), an efficient CYP2E1 inhibitor. Interestingly, N-acetyl-L-cysteine (NAC) significantly attenuated chronic ethanol-induced hepatic fat accumulation and the decline of Akt phosphorylation at Thr308. In the in vitro studies, Akt phosphorylation was suppressed in CYP2E1-expressing HepG2 (CYP2E1-HepG2) cells compared with the negative control HepG2 (NC-HepG2) cells, and 4-HNE treatment led to significant decrease of Akt phosphorylation at Thr308 in wild type HepG2 cells. Lastly, pharmacological activation of Akt by insulin-like growth factor-1 (IGF-1) significantly alleviated chronic ethanol-induced fatty liver in mice. Collectively, these results indicate that CYP2E1-induced oxidative stress may be responsible for ethanol-induced suppression of Akt phosphorylation and pharmacological modulation of Akt in liver may be an effective strategy for the treatment of ethanol-induced fatty liver.
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Affiliation(s)
- Tao Zeng
- Institute of Toxicology, School of Public Health, Shandong University, China.
| | - Cui-Li Zhang
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Ning Zhao
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Min-Jie Guan
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Mo Xiao
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Rui Yang
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Xiu-Lan Zhao
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Li-Hua Yu
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Zhen-Ping Zhu
- Institute of Toxicology, School of Public Health, Shandong University, China
| | - Ke-Qin Xie
- Institute of Toxicology, School of Public Health, Shandong University, China.
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Tanaka N, Aoyama T, Kimura S, Gonzalez FJ. Targeting nuclear receptors for the treatment of fatty liver disease. Pharmacol Ther 2017; 179:142-157. [PMID: 28546081 DOI: 10.1016/j.pharmthera.2017.05.011] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ligand-activated nuclear receptors, including peroxisome proliferator-activated receptor alpha (PPARα), pregnane X receptor, and constitutive androstane receptor, were first identified as key regulators of the responses against chemical toxicants. However, numerous studies using mouse disease models and human samples have revealed critical roles for these receptors and others, such as PPARβ/δ, PPARγ, farnesoid X receptor (FXR), and liver X receptor (LXR), in maintaining nutrient/energy homeostasis in part through modulation of the gut-liver-adipose axis. Recently, disorders associated with disrupted nutrient/energy homeostasis, e.g., obesity, metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD), are increasing worldwide. Notably, in NAFLD, a progressive subtype exists, designated as non-alcoholic steatohepatitis (NASH) that is characterized by typical histological features resembling alcoholic steatohepatitis (ASH), and NASH/ASH are recognized as major causes of hepatitis virus-unrelated liver cirrhosis and hepatocellular carcinoma. Since hepatic steatosis is basically caused by an imbalance between fat/energy influx and utilization, abnormal signaling of these nuclear receptors contribute to the pathogenesis of fatty liver disease. Standard therapeutic interventions have not been fully established for fatty liver disease, but some new agents that activate or inhibit nuclear receptor signaling have shown promise as possible therapeutic targets. In this review, we summarize recent findings on the roles of nuclear receptors in fatty liver disease and discuss future perspectives to develop promising pharmacological strategies targeting nuclear receptors for NAFLD/NASH.
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Affiliation(s)
- Naoki Tanaka
- Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan.
| | - Toshifumi Aoyama
- Department of Metabolic Regulation, Shinshu University Graduate School of Medicine, Matsumoto, Nagano, Japan
| | - Shioko Kimura
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Frank J Gonzalez
- Laboratory of Metabolism, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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Pioglitazone attenuates the opioid withdrawal and vulnerability to relapse to heroin seeking in rodents. Psychopharmacology (Berl) 2017; 234:223-234. [PMID: 27714428 DOI: 10.1007/s00213-016-4452-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 09/26/2016] [Indexed: 01/10/2023]
Abstract
RATIONALE Relapse to opioids is often driven by the avoidance of the aversive states of opioid withdrawal. We recently demonstrated that activation of peroxisome proliferator-activated receptor gamma (PPARγ) by pioglitazone reduces the motivation for heroin and attenuates its rewarding properties. However, the role of PPARγ in withdrawal and other forms of relapse to heroin is unknown. OBJECTIVES To further address this issue, we investigated the role of PPARγ on the development and expression of morphine withdrawal in mice and the effect of pioglitazone on several forms of heroin relapse in rats. METHODS We induced physical dependence to morphine in mice by injecting morphine twice daily for 6 days. Withdrawal syndrome was precipitated on day 6 with an injection of naloxone. In addition, different groups of rats were trained to self-administer heroin and, after the extinction, the relapse was elicited by cues, priming, or stress. The effect of different doses of pioglitazone was tested on these different paradigms. RESULTS Data show that chronic and acute administration of pioglitazone attenuates morphine withdrawal symptoms, and these effects are mediated by activation of PPARγ receptors. Activation of PPARγ by pioglitazone also abolishes yohimbine-induced reinstatement of heroin seeking and reduces heroin-induced reinstatement, while it does not affect cue-induced relapse. CONCLUSIONS These findings provide new insights on the role of PPARγ on opioid dependence and suggest that pioglitazone may be useful for the treatment of opioid withdrawal in opioid-addicted individuals.
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Low- ω3 Fatty Acid and Soy Protein Attenuate Alcohol-Induced Fatty Liver and Injury by Regulating the Opposing Lipid Oxidation and Lipogenic Signaling Pathways. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:1840513. [PMID: 28074114 PMCID: PMC5203909 DOI: 10.1155/2016/1840513] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/14/2016] [Accepted: 11/15/2016] [Indexed: 12/20/2022]
Abstract
Chronic ethanol-induced downregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) and upregulation of peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC1β) affect hepatic lipid oxidation and lipogenesis, respectively, leading to fatty liver injury. Low-ω3 fatty acid (Low-ω3FA) that primarily regulates PGC1α and soy protein (SP) that seems to have its major regulatory effect on PGC1β were evaluated for their protective effects against ethanol-induced hepatosteatosis in rats fed with Lieber-deCarli control or ethanol liquid diets with high or low ω3FA fish oil and soy protein. Low-ω3FA and SP opposed the actions of chronic ethanol by reducing serum and liver lipids with concomitant decreased fatty liver. They also prevented the downregulation of hepatic Sirtuin 1 (SIRT1) and PGC1α and their target fatty acid oxidation pathway genes and attenuated the upregulation of hepatic PGC1β and sterol regulatory element-binding protein 1c (SREBP1c) and their target lipogenic pathway genes via the phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK). Thus, these two novel modulators attenuate ethanol-induced hepatosteatosis and consequent liver injury potentially by regulating the two opposing lipid oxidation and lipogenic pathways.
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Ansari RA, Husain K, Rizvi SAA. Role of Transcription Factors in Steatohepatitis and Hypertension after Ethanol: The Epicenter of Metabolism. Biomolecules 2016; 6:biom6030029. [PMID: 27348013 PMCID: PMC5039415 DOI: 10.3390/biom6030029] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 05/25/2016] [Accepted: 06/08/2016] [Indexed: 02/07/2023] Open
Abstract
Chronic alcohol consumption induces multi-organ damage, including alcoholic liver disease (ALD), pancreatitis and hypertension. Ethanol and ethanol metabolic products play a significant role in the manifestation of its toxicity. Ethanol metabolizes to acetaldehyde and produces reduced nicotinamide adenine dinucleotide (NADH) by cytosolic alcohol dehydrogenase. Ethanol metabolism mediated by cytochrome-P450 2E1 causes oxidative stress due to increased production of reactive oxygen species (ROS). Acetaldehyde, increased redox cellular state and ROS activate transcription factors, which in turn activate genes for lipid biosynthesis and offer protection of hepatocytes from alcohol toxicity. Sterol regulatory element binding proteins (SREBPs) and peroxisome proliferator activated-receptors (PPARs) are two key lipogenic transcription factors implicated in the development of fatty liver in alcoholic and non-alcoholic steatohepatitis. SREBP-1 is activated in the livers of chronic ethanol abusers. An increase in ROS activates nuclear factor erythroid-2-related factor-2 (Nrf2) and hypoxia inducible factor (HIF) to provide protection to hepatocytes from ethanol toxicity. Under ethanol exposure, due to increased gut permeability, there is release of gram-negative bacteria-derived lipopolysaccharide (LPS) from intestine causing activation of immune response. In addition, the metabolic product, acetaldehyde, modifies the proteins in hepatocyte, which become antigens inviting auto-immune response. LPS activates macrophages, especially the liver resident macrophages, Kupffer cells. These Kupffer cells and circulating macrophages secrete various cytokines. The level of tumor necrosis factor-α (TNFα), interleukin-1beta (IL-1β), IL-6, IL-8 and IL-12 have been found elevated among chronic alcoholics. In addition to elevation of these cytokines, the peripheral iron (Fe(2+)) is also mobilized. An increased level of hepatic iron has been observed among alcoholics. Increased ROS, IL-1β, acetaldehyde, and increased hepatic iron, all activate nuclear factor-kappa B (NF-κB) transcription factor. Resolution of increased reactive oxygen species requires increased expression of genes responsible for dismutation of increased ROS which is partially achieved by IL-6 mediated activation of signal transducers and activators of transcription 3 (STAT3). In addition to these transcription factors, activator protein-1 may also be activated in hepatocytes due to its association with resolution of increased ROS. These transcription factors are central to alcohol-mediated hepatotoxicity.
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Affiliation(s)
- Rais A Ansari
- Department of Pharmaceutical Sciences, College of Pharmacy, Health Professions Division, Nova Southeastern University, 3200 S University Drive, Fort Lauderdale, FL 33328, USA.
| | - Kazim Husain
- Department of Physiology, Pharmacology and Toxicology, Ponce School of Medicine, P.O. Box 7004, Ponce, PR 00732-2575, USA.
| | - Syed A A Rizvi
- Department of Pharmaceutical Sciences, College of Pharmacy, Health Professions Division, Nova Southeastern University, 3200 S University Drive, Fort Lauderdale, FL 33328, USA.
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17
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Zhang W, Sun Q, Zhong W, Sun X, Zhou Z. Hepatic Peroxisome Proliferator-Activated Receptor Gamma Signaling Contributes to Alcohol-Induced Hepatic Steatosis and Inflammation in Mice. Alcohol Clin Exp Res 2016; 40:988-99. [PMID: 27062444 DOI: 10.1111/acer.13049] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 02/18/2016] [Indexed: 12/25/2022]
Abstract
BACKGROUND Peroxisome proliferator-activated receptor gamma (PPARγ) signaling has been shown to regulate lipogenesis and lipid accumulation. Previous studies have shown that hepatic PPARγ is up-regulated in steatotic liver of both animal and human. However, the effects of hepatic PPARγ signaling on alcoholic liver disease (ALD) remain elusive. METHODS To determine the role of hepatic PPARγ signaling on ALD, wild-type (WT) and hepatocyte-specific PPARγ knockdown (PPARγ∆Hep) mice were fed a modified Lieber-DeCarli alcohol or isocaloric maltose dextrin control liquid diet for 8 weeks to induce ALD. Blood parameters, hepatic steatosis, and inflammation were measured after 8-week alcohol feeding. RESULTS Alcohol feeding to WT mice resulted in liver damage (alanine aminotransferase [ALT], 94.68 ± 17.05 U/L; aspartate aminotransferase [AST], 55.87 ± 11.29 U/L), which was significantly alleviated by hepatic PPARγ knockdown (ALT, 57.36 ± 14.98 U/L; AST, 38.06 ± 3.35 U/L). Alcohol feeding led to marked lipid accumulation and up-regulation of lipogenic genes including fatty acid transport protein 1 (FATP1), acetyl-CoA carboxylase (ACC), fatty acid synthase (FASN), lipin1 (LIPIN1), diacylglycerol acyltransferase 1 (DGAT1), and diacylglycerol acyltransferase 2 (DGAT2) in the livers of WT mice. Knockdown of hepatic PPARγ significantly alleviated alcohol-induced lipid accumulation and abolished the up-regulation of FASN, DGAT1, and DGAT2. Silencing of PPARγ in FL83B cells significantly decreased ethanol (EtOH)-, linoleic acid-, and EtOH plus linoleic acid-induced lipid accumulation. Knockdown of hepatic PPARγ also significantly reduced alcohol-induced inflammatory chemokine (monocyte chemotactic protein 1 [MCP1], keratinocyte-derived chemokine [KC], interferon gamma-induced protein 10 [IP-10]) and inflammatory infiltration (lymphocyte antigen 6 complex, locus G [Ly6G], and F4/80). CONCLUSIONS The results suggest that hepatic PPARγ signaling contributes to alcohol-induced liver injury by promoting hepatic steatosis and inflammation.
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Affiliation(s)
- Wenliang Zhang
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Qian Sun
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina.,Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Wei Zhong
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Xinguo Sun
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
| | - Zhanxiang Zhou
- Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina.,Department of Nutrition, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina
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van der Veen JN, Lingrell S, Gao X, Quiroga AD, Takawale A, Armstrong EA, Yager JY, Kassiri Z, Lehner R, Vance DE, Jacobs RL. Pioglitazone attenuates hepatic inflammation and fibrosis in phosphatidylethanolamine N-methyltransferase-deficient mice. Am J Physiol Gastrointest Liver Physiol 2016; 310:G526-38. [PMID: 26797396 DOI: 10.1152/ajpgi.00243.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/21/2015] [Indexed: 01/31/2023]
Abstract
Phosphatidylethanolamine N-methyltransferase (PEMT) is an important enzyme in hepatic phosphatidylcholine (PC) biosynthesis. Pemt(-/-) mice are protected against high-fat diet (HFD)-induced obesity and insulin resistance; however, these mice develop nonalcoholic fatty liver disease (NAFLD). We hypothesized that peroxisomal proliferator-activated receptor-γ (PPARγ) activation by pioglitazone might stimulate adipocyte proliferation, thereby directing lipids from the liver toward white adipose tissue. Pioglitazone might also act directly on PPARγ in the liver to improve NAFLD. Pemt(+/+) and Pemt(-/-) mice were fed a HFD with or without pioglitazone (20 mg·kg(-1)·day(-1)) for 10 wk. Pemt(-/-) mice were protected from HFD-induced obesity but developed NAFLD. Treatment with pioglitazone caused an increase in body weight gain in Pemt(-/-) mice that was mainly due to increased adiposity. Moreover, pioglitazone improved NAFLD in Pemt(-/-) mice, as indicated by a 35% reduction in liver weight and a 57% decrease in plasma alanine transaminase levels. Livers from HFD-fed Pemt(-/-) mice were steatotic, inflamed, and fibrotic. Hepatic steatosis was still evident in pioglitazone-treated Pemt(-/-) mice; however, treatment with pioglitazone reduced hepatic fibrosis, as evidenced by reduced Sirius red staining and lowered mRNA levels of collagen type Iα1 (Col1a1), tissue inhibitor of metalloproteinases 1 (Timp1), α-smooth muscle actin (Acta2), and transforming growth factor-β (Tgf-β). Similarly, oxidative stress and inflammation were reduced in livers from Pemt(-/-) mice upon treatment with pioglitazone. Together, these data show that activation of PPARγ in HFD-fed Pemt(-/-) mice improved liver function, while these mice were still protected against diet-induced obesity and insulin resistance.
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Affiliation(s)
- Jelske N van der Veen
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Susanne Lingrell
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Xia Gao
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Ariel D Quiroga
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Abhijit Takawale
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Edward A Armstrong
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Jerome Y Yager
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Zamaneh Kassiri
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada; and
| | - Richard Lehner
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Dennis E Vance
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada
| | - René L Jacobs
- Group on the Molecular and Cell Biology of Lipids, University of Alberta, Edmonton, Alberta, Canada; Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
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Cave MC, Clair HB, Hardesty JE, Falkner KC, Feng W, Clark BJ, Sidey J, Shi H, Aqel BA, McClain CJ, Prough RA. Nuclear receptors and nonalcoholic fatty liver disease. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2016; 1859:1083-1099. [PMID: 26962021 DOI: 10.1016/j.bbagrm.2016.03.002] [Citation(s) in RCA: 196] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 02/08/2023]
Abstract
Nuclear receptors are transcription factors which sense changing environmental or hormonal signals and effect transcriptional changes to regulate core life functions including growth, development, and reproduction. To support this function, following ligand-activation by xenobiotics, members of subfamily 1 nuclear receptors (NR1s) may heterodimerize with the retinoid X receptor (RXR) to regulate transcription of genes involved in energy and xenobiotic metabolism and inflammation. Several of these receptors including the peroxisome proliferator-activated receptors (PPARs), the pregnane and xenobiotic receptor (PXR), the constitutive androstane receptor (CAR), the liver X receptor (LXR) and the farnesoid X receptor (FXR) are key regulators of the gut:liver:adipose axis and serve to coordinate metabolic responses across organ systems between the fed and fasting states. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease and may progress to cirrhosis and even hepatocellular carcinoma. NAFLD is associated with inappropriate nuclear receptor function and perturbations along the gut:liver:adipose axis including obesity, increased intestinal permeability with systemic inflammation, abnormal hepatic lipid metabolism, and insulin resistance. Environmental chemicals may compound the problem by directly interacting with nuclear receptors leading to metabolic confusion and the inability to differentiate fed from fasting conditions. This review focuses on the impact of nuclear receptors in the pathogenesis and treatment of NAFLD. Clinical trials including PIVENS and FLINT demonstrate that nuclear receptor targeted therapies may lead to the paradoxical dissociation of steatosis, inflammation, fibrosis, insulin resistance, dyslipidemia and obesity. Novel strategies currently under development (including tissue-specific ligands and dual receptor agonists) may be required to separate the beneficial effects of nuclear receptor activation from unwanted metabolic side effects. The impact of nuclear receptor crosstalk in NAFLD is likely to be profound, but requires further elucidation. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.
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Affiliation(s)
- Matthew C Cave
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA; The KentuckyOne Health Jewish Hospital Liver Transplant Program, Louisville, KY 40202, USA.
| | - Heather B Clair
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Josiah E Hardesty
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - K Cameron Falkner
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Wenke Feng
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Barbara J Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Jennifer Sidey
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Hongxue Shi
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Bashar A Aqel
- Department of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic College of Medicine, Scottsdale, AZ 85054, USA
| | - Craig J McClain
- Department of Medicine, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY 40202, USA; The Robley Rex Veterans Affairs Medical Center, Louisville, KY 40206, USA; The KentuckyOne Health Jewish Hospital Liver Transplant Program, Louisville, KY 40202, USA
| | - Russell A Prough
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY 40202, USA
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Zhang P, Ma D, Wang Y, Zhang M, Qiang X, Liao M, Liu X, Wu H, Zhang Y. Berberine protects liver from ethanol-induced oxidative stress and steatosis in mice. Food Chem Toxicol 2015; 74:225-32. [PMID: 25455889 DOI: 10.1016/j.fct.2014.10.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 10/04/2014] [Accepted: 10/08/2014] [Indexed: 12/11/2022]
Abstract
Alcohol consumption is customary in many cultures and it is a common human behavior worldwide. Binge ethanol and chronic alcohol consumption, two usual drinking patterns of human beings, produce a state of oxidative stress in liver and disturb the liver function. However, a safe and effective therapy for alcoholic liver disease in humans is still elusive. This study identified the natural product berberine as a potential agent for treating or preventing ethanol-induced liver injury. We demonstrated that berberine attenuated oxidative stress resulted from binge drinking in liver by reducing hepatic lipid peroxidation, glutathione exhaust and mitochondrial oxidative damage. Furthermore, berberine also prevented the oxidative stress and macrosteatosis in response to chronic ethanol exposure in mice. Either the total cytochrome P450 2E1 or the mitochondria-located cytochrome P450 2E1, which is implicated in ethanol-mediated oxidative stress, was suppressed by berberine. On the other hand, berberine significantly blunted the lipid accumulation in liver due to chronic alcohol consumption, at least partially, through restoring peroxisome proliferator-activated receptor α/peroxisome proliferator-activated receptor-gamma Co-activator-1α and hepatocyte nuclear factor 4α/microsomal triglyceride transfer protein pathways. These findings suggested that berberine could serve as a potential agent for preventing or treating human alcoholic liver disease.
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Affiliation(s)
- Pengcheng Zhang
- State Key Laboratory of Natural Medicines, Department of Biochemistry, China Pharmaceutical University, Nanjing 210009, China
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Carr RM, Correnti J. Insulin resistance in clinical and experimental alcoholic liver disease. Ann N Y Acad Sci 2015; 1353:1-20. [PMID: 25998863 DOI: 10.1111/nyas.12787] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Alcoholic liver disease (ALD) is the number one cause of liver failure worldwide; its management costs billions of healthcare dollars annually. Since the advent of the obesity epidemic, insulin resistance (IR) and diabetes have become common clinical findings in patients with ALD; and the development of IR predicts the progression from simple steatosis to cirrhosis in ALD patients. Both clinical and experimental data implicate the impairment of several mediators of insulin signaling in ALD, and experimental data suggest that insulin-sensitizing therapies improve liver histology. This review explores the contribution of impaired insulin signaling in ALD and summarizes the current understanding of the synergistic relationship between alcohol and nutrient excess in promoting hepatic inflammation and disease.
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Affiliation(s)
- Rotonya M Carr
- Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jason Correnti
- Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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22
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Na TY, Han YH, Ka NL, Park HS, Kang YP, Kwon SW, Lee BH, Lee MO. 22-S-Hydroxycholesterol protects against ethanol-induced liver injury by blocking the auto/paracrine activation of MCP-1 mediated by LXRα. J Pathol 2015; 235:710-20. [PMID: 25557254 PMCID: PMC6084351 DOI: 10.1002/path.4494] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 11/05/2014] [Accepted: 11/29/2014] [Indexed: 02/01/2023]
Abstract
Chronic ethanol consumption causes hepatic steatosis and inflammation, which are associated with liver hypoxia. Monocyte chemoattractant protein‐1 (MCP‐1) is a hypoxia response factor that determines recruitment and activation of monocytes to the site of tissue injury. The level of MCP‐1 is elevated in the serum and liver of patients with alcoholic liver disease (ALD); however, the molecular details regarding the regulation of MCP‐1 expression are not yet understood completely. Here, we show the role of liver X receptor α (LXRα) in the regulation of MCP‐1 expression during the development of ethanol‐induced fatty liver injury, using an antagonist, 22‐S‐hydroxycholesterol (22‐S‐HC). First, administration of 22‐S‐HC attenuated the signs of liver injury with decreased levels of MCP‐1 and its receptor CCR2 in ethanol‐fed mice. Second, hypoxic conditions or treatment with the LXRα agonist GW3965 significantly induced the expression of MCP‐1, which was completely blocked by treatment with 22‐S‐HC or infection by shLXRα lentivirus in the primary hepatocytes. Third, over‐expression of LXRα or GW3965 treatment increased MCP‐1 promoter activity by increasing the binding of hypoxia‐inducible factor‐1α to the hypoxia response elements, together with LXRα. Finally, treatment with recombinant MCP‐1 increased the level of expression of LXRα and LXRα‐dependent lipid droplet accumulation in both hepatocytes and Kupffer cells. These data show that LXRα and its ligand‐induced up‐regulation of MCP‐1 and MCP‐1‐induced LXRα‐dependent lipogenesis play a key role in the autocrine and paracrine activation of MCP‐1 in the pathogenesis of alcoholic fatty liver disease, and that this activation may provide a promising new target for ALD therapy.Copyright © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Tae-Young Na
- College of Pharmacy, Seoul National University, Korea
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Blednov YA, Benavidez JM, Black M, Ferguson LB, Schoenhard GL, Goate AM, Edenberg HJ, Wetherill L, Hesselbrock V, Foroud T, Harris RA. Peroxisome proliferator-activated receptors α and γ are linked with alcohol consumption in mice and withdrawal and dependence in humans. Alcohol Clin Exp Res 2015; 39:136-45. [PMID: 25516156 PMCID: PMC4308472 DOI: 10.1111/acer.12610] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 10/19/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND Peroxisome proliferator-activated receptor (PPAR) agonists reduce voluntary ethanol (EtOH) consumption in rat models and are promising therapeutics in the treatment for drug addictions. We studied the effects of different classes of PPAR agonists on chronic EtOH intake and preference in mice with a genetic predisposition for high alcohol consumption and then examined human genomewide association data for polymorphisms in PPAR genes in alcohol-dependent subjects. METHODS Two different behavioral tests were used to measure intake of 15% EtOH in C57BL/6J male mice: 24-hour 2-bottle choice and limited access (3-hour) 2-bottle choice, drinking in the dark. We measured the effects of pioglitazone (10 and 30 mg/kg), fenofibrate (50 and 150 mg/kg), GW0742 (10 mg/kg), tesaglitazar (1.5 mg/kg), and bezafibrate (25 and 75 mg/kg) on EtOH intake and preference. Fenofibric acid, the active metabolite of fenofibrate, was quantified in mouse plasma, liver, and brain by liquid chromatography tandem mass spectrometry. Data from a human genome-wide association study (GWAS) completed in the Collaborative Study on the Genetics of Alcoholism (COGA) were then used to analyze the association of single nucleotide polymorphisms (SNPs) in different PPAR genes (PPARA, PPARD, PPARG, and PPARGC1A) with 2 phenotypes: DSM-IV alcohol dependence (AD) and the DSM-IV criterion of withdrawal. RESULTS Activation of 2 isoforms of PPARs, α and γ, reduced EtOH intake and preference in the 2 different consumption tests in mice. However, a selective PPARδ agonist or a pan agonist for all 3 PPAR isoforms did not decrease EtOH consumption. Fenofibric acid, the active metabolite of the PPARα agonist fenofibrate, was detected in liver, plasma, and brain after 1 or 8 days of oral treatment. The GWAS from COGA supported an association of SNPs in PPARA and PPARG with alcohol withdrawal and PPARGC1A with AD but found no association for PPARD with either phenotype. CONCLUSIONS We provide convergent evidence using both mouse and human data for specific PPARs in alcohol action. Reduced EtOH intake in mice and the genetic association between AD or withdrawal in humans highlight the potential for repurposing FDA-approved PPARα or PPARγ agonists for the treatment of AD.
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Affiliation(s)
- Yuri A. Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
| | - Jillian M. Benavidez
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
| | - Laura B. Ferguson
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
- Institute for Neuroscience, The University of Texas at Austin, Austin, TX 78712
| | | | - Alison M. Goate
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110
| | | | - Leah Wetherill
- Indiana University School of Medicine, Indianapolis, IN 46202
| | | | - Tatiana Foroud
- Indiana University School of Medicine, Indianapolis, IN 46202
| | - R. Adron Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX 78712
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Yamagata H, Ikejima K, Takeda K, Aoyama T, Kon K, Okumura K, Watanabe S. Altered expression and function of hepatic natural killer T cells in obese and diabetic KK-A(y) mice. Hepatol Res 2013; 43:276-88. [PMID: 22834991 DOI: 10.1111/j.1872-034x.2012.01062.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIM To evaluate the role of natural killer (NK)T cells in the pathogenesis of non-alcoholic steatohepatitis (NASH), here we investigated the expression and function of hepatic NKT cells in KK-A(y) mice, an animal model of metabolic syndrome. METHODS Male, 8-week-old KK-A(y) and C57Bl/6 mice were fed a high-fat (HF) diet for 4 weeks. Some mice were given daily intragastric injections of pioglitazone for 5 days prior to or after dietary treatment. RESULTS In untreated KK-A(y) mice, the percentages of NKT cells in liver mononucleolar cells were nearly one-third of those in C57Bl/6 controls. Elevations in interleukin (IL)-4 and interferon (IFN)-γ mRNA in the liver after a single injection of α-galactosylceramide (GalCer) were blunted in KK-A(y) mice largely. Percentages of NKT cells, as well as GalCer-induced increases in IL-4 mRNA, were blunted significantly in both strains after HF diet feeding for 4 weeks. Interestingly, KK-A(y) mice pretreated with pioglitazone showed significant increases in NKT cell proportion, and GalCer-induced increases in IL-4 and IFN-γ mRNA were also enhanced by pioglitazone. In KK-A(y) mice, the percentages of annexin V positive NKT cells were nearly 2.5-fold higher than those in C57Bl/6 controls; however, pioglitazone decreased annexin V positive cells significantly. Moreover, pioglitazone increased NKT cell fraction in KK-A(y) mice even after HF diet feeding. CONCLUSION KK-A(y) mice exhibit proportional and functional alterations in hepatic NKT cells in close relation with the development of steatohepatitis, and it is postulated that pioglitazone improves steatohepatitis in part through restoration of hepatic NKT cells.
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Affiliation(s)
- Hisafumi Yamagata
- Departments of Gastroenterology Immunology, Juntendo University Graduate School of Medicine, Tokyo, Japan
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25
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Ramirez T, Tong M, Chen WC, Nguyen QG, Wands JR, de la Monte SM. Chronic alcohol-induced hepatic insulin resistance and endoplasmic reticulum stress ameliorated by peroxisome-proliferator activated receptor-δ agonist treatment. J Gastroenterol Hepatol 2013; 28:179-87. [PMID: 22988930 PMCID: PMC4406771 DOI: 10.1111/j.1440-1746.2012.07256.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/10/2012] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIM Chronic alcoholic liver disease is associated with hepatic insulin resistance, dysregulated lipid metabolism with increased toxic lipid (ceramide) accumulation, lipid peroxidation, and oxidative and endoplasmic reticulum (ER) stress. Peroxisome-proliferator activated receptor (PPAR) agonists are insulin sensitizers that can restore hepatic insulin responsiveness in both alcohol and non-alcohol-related steatohepatitis. Herein, we demonstrate that treatment with a PPAR-δ agonist enhances insulin signaling and reduces the severities of ER stress and ceramide accumulation in an experimental model of ethanol-induced steatohepatitis. METHODS Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% or 37% ethanol (caloric) for 8 weeks. After 3 weeks on the diets, rats were treated with vehicle or PPAR-δ agonist twice weekly by i.p. injection. RESULTS Ethanol-fed rats developed steatohepatitis with inhibition of signaling through the insulin and insulin-like growth factor-1 receptors, and Akt activated pathways. Despite continued ethanol exposure, PPAR-δ agonist co-treatments increased Akt activation, reduced multiple molecular indices of ER stress and steatohepatitis. CONCLUSIONS These results suggest that PPAR-δ agonist rescue of chronic alcoholic liver disease is mediated by enhancement of insulin signaling through Akt/metabolic pathways that reduce lipotoxicity and ER stress.
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Affiliation(s)
- Teresa Ramirez
- Liver Research Center and Department of Medicine, Rhode Island Hospital and Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903, USA
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26
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Zhang F, Kong D, Lu Y, Zheng S. Peroxisome proliferator-activated receptor-γ as a therapeutic target for hepatic fibrosis: from bench to bedside. Cell Mol Life Sci 2013; 70:259-76. [PMID: 22699820 PMCID: PMC11113701 DOI: 10.1007/s00018-012-1046-x] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/18/2012] [Accepted: 05/29/2012] [Indexed: 02/07/2023]
Abstract
Hepatic fibrosis is a dynamic chronic liver disease occurring as a consequence of wound-healing responses to various hepatic injuries. This disorder is one of primary predictors for liver-associated morbidity and mortality worldwide. To date, no pharmacological agent has been approved for hepatic fibrosis or could be recommended for routine use in clinical context. Cellular and molecular understanding of hepatic fibrosis has revealed that peroxisome proliferator-activated receptor-γ (PPARγ), the functioning receptor for antidiabetic thiazolidinediones, plays a pivotal role in the pathobiology of hepatic stellate cells (HSCs), whose activation is the central event in the pathogenesis of hepatic fibrosis. Activation of PPARγ inhibits HSC collagen production and modulates HSC adipogenic phenotype at transcriptional and epigenetic levels. These molecular insights indicate PPARγ as a promising drug target for antifibrotic chemotherapy. Intensive animal studies have demonstrated that stimulation of PPARγ regulatory system through gene therapy approaches and PPARγ ligands has therapeutic promise for hepatic fibrosis induced by a variety of etiologies. At the same time, thiazolidinedione agents have been investigated for their clinical benefits primarily in patients with nonalcoholic steatohepatitis, a common metabolic liver disorder with high potential to progress to fibrosis and liver-related death. Although some studies have shown initial promise, none has established long-term efficacy in well-controlled randomized clinical trials. This comprehensive review covers the 10-year discoveries of the molecular basis for PPARγ regulation of HSC pathophysiology and then focuses on the animal investigations and clinical trials of various therapeutic modalities targeting PPARγ for hepatic fibrosis.
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Affiliation(s)
- Feng Zhang
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Desong Kong
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
| | - Yin Lu
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210046 China
- National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing, 210046 China
| | - Shizhong Zheng
- Department of Clinical Pharmacy, College of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, 210029 Jiangsu China
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, 210046 China
- National First-Class Key Discipline for Traditional Chinese Medicine of Nanjing University of Chinese Medicine, Nanjing, 210046 China
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Wang L, Wang GL, Liu JH, Li D, Zhu DZ, Wu LN. [Effects of ursolic acid in ameliorating insulin resistance in liver of KKAy mice via peroxisome proliferator-activated receptors α and γ]. ZHONG XI YI JIE HE XUE BAO = JOURNAL OF CHINESE INTEGRATIVE MEDICINE 2012; 10:793-9. [PMID: 22805086 DOI: 10.3736/jcim20120710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
OBJECTIVE To explore the effects and mechanism of ursolic acid in improving hepatic insulin resistance in KKAy mice with spontaneous type 2 diabetes. METHODS Thirty-five KKAy mice were divided into five groups according to the randomized block design, namely, control, rosiglitazone, fenofibrate, and high- and low-dose ursolic acid groups with seven mice in each group. C57BL/6J mice were used as the normal control group. At the end of the 4th week, free fatty acid (FFA), tumor necrosis factor-α (TNF-α) and adiponectin contents in serum were detected by enzyme-linked immunosorbent assay; the protein expressions of phosphoenolpyruvate carboxykinase (PEPCK), insulin receptor substrate-2 (IRS-2) and glucose transport factor-2 (GLUT-2) were detected by Western blot method; the mRNA expressions of PEPCK, IRS-2 and GLUT-2 were detected by real-time polymerase chain reaction; the expressions of peroxisome proliferator-activated receptor α (PPARα) and peroxisome proliferator-activated receptor γ (PPARγ) in liver tissue were detected by immunohistochemical method. RESULTS After four weeks of intervention, the contents of FFA, TNF-α and adiponectin in serum of the high-dose ursolic acid group had changed, showing statistically significant difference compared to those of the control group (P<0.01); high dose of ursolic acid had depressant effect on the expressions of PEPCK protein and PEPCK mRNA (P<0.01); low dose of ursolic acid depressed the expression of PEPCK mRNA and induced phosphorylation of IRS-2 in the liver (P<0.05); both high and low dose of ursolic acid improved the expression of PPARα in the liver (P<0.01). CONCLUSION The effects of ursolic acid in improving hepatic insulin resistance in KKAy mice with spontaneous type 2 diabetes may be closely related to affecting the contents of FFA, TNF-α and adiponectin, improving the expression of PPARα protein, regulating transcription of PEPCK protein and inducing phosphorylation of IRS-2.
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Affiliation(s)
- Lin Wang
- Department of Traditional Chinese Medicine, Changhai Hospital, Second Military Medical University, Shanghai, China
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28
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The Current Knowledge of the Role of PPAR in Hepatic Ischemia-Reperfusion Injury. PPAR Res 2012; 2012:802384. [PMID: 22675337 PMCID: PMC3363006 DOI: 10.1155/2012/802384] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 03/16/2012] [Indexed: 12/15/2022] Open
Abstract
Strategies to improve the viability of steatotic livers could reduce the risk of dysfunction after surgery and increase the number of organs suitable for transplantation. Peroxisome proliferator-activated receptors (PPARs) are major regulators of lipid metabolism and inflammation. In this paper, we review the PPAR signaling pathways and present some of their lesser-known functions in liver regeneration. Potential therapies based on PPAR regulation will be discussed. The data suggest that further investigations are required to elucidate whether PPAR could be a potential therapeutic target in liver surgery and to determine the most effective therapies that selectively regulate PPAR with minor side effects.
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29
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Liu J, Takase I, Hakucho A, Okamura N, Fujimiya T. Carvedilol attenuates the progression of alcohol fatty liver disease in rats. Alcohol Clin Exp Res 2012; 36:1587-99. [PMID: 22413959 DOI: 10.1111/j.1530-0277.2012.01773.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 12/20/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND Hepatosteatosis is an essential step in liver disease progression. However, the mechanisms that mediate the progression of hepatosteatosis and the optimal inhibitor of them remain largely unclear. The sympathetic nervous system (SNS) is responsible for the lipid metabolism and the accumulation of collagen that occurs in an injured liver. Medicines that inhibit this pathway may be a relevant treatment for the hepatosteatosis, and then reduce the liver injury that progresses through the stage of steatosis to fibrosis. METHODS Using an ethanol-liquid-diet-fed rat model of alcohol fatty liver disease (AFLD), we studied the effects of carvedilol, which can block the SNS completely via β1, β2, and α1 adrenergic receptors, on the sympathetic tone, hepatosteatosis, and fibrosis based on histological, immunohistochemical, Western blot, and reverse transcriptase polymerase chain reaction analyses. RESULTS Carvedilol inhibited the ethanol-induced whole-body and hepatic sympathetic activities based on the serum 3-methoxy-4-hydroxyphenylglycol level and hepatic tyrosine hydroxylase expression. Carvedilol attenuated the hepatosteatosis, as evidenced by reduced hepatic triglyceride level and the accumulation of fatty droplets within hepatocytes, down-regulated fatty acid synthase and sterol regulatory element binding protein-1, and up-regulated peroxisome proliferator-activated receptor-α. No fibrosis signs were shown in our rat model. Carvedilol inhibited ethanol-induced the thickening of zone 3 vessel walls, reduced the activation of hepatic stellate cells (HSCs), and decreased the induction of collagen, transforming growth factor β1, and tissue inhibitor of metalloproteinases-1. Tumor necrosis factor α (TNF-α) was expressed on the activated HSCs and inhibited by carvedilol based on the immunohistochemical double staining analysis. CONCLUSIONS Ethanol metabolism-induced lipogenesis may trigger the SNS-activated HSCs feedback loop, and then induct the activated HSCs and the activated HSCs-derived TNF-α, the mediator of lipogenesis, overproduction. Carvedilol may block this feedback loop via antisympathetic activity and demonstrate its preventive role on the development of hepatosteatosis in rat with AFLD.
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Affiliation(s)
- Jinyao Liu
- Department of Legal Medicine, Yamaguchi University Graduate School of Medicine, Ube, Japan.
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30
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Aroor AR, Jackson DE, Shukla SD. Dysregulated phosphorylation and nuclear translocation of cyclic AMP response element binding protein (CREB) in rat liver after chronic ethanol binge. Eur J Pharmacol 2012; 679:101-8. [PMID: 22269225 DOI: 10.1016/j.ejphar.2011.12.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 12/21/2011] [Accepted: 12/28/2011] [Indexed: 01/26/2023]
Abstract
Binge ethanol during chronic ethanol abuse augments liver injury but the underlying mechanism remains unknown. CREB (cyclic AMP response element binding protein) is implicated as a key transcription factor in liver regeneration and hepatic glucose and lipid metabolism. We examined the effects of ethanol on the phosphorylation of CREB in hepatocytes, and in vivo in rat liver after chronic ethanol binge. For in vivo studies, rats were fed ethanol in liquid diet for 4 weeks followed by single binge administration of ethanol (intragastric, 5 g/kg body weight). Four hours after binge administration, liver samples were collected and analyzed. Treatment of hepatocytes with ethanol caused increased phosphorylation of p38 MAPK (mitogen activated protein kinase), MSK-1 (mitogen and stress activated kinase) and CREB in the nuclear compartment without activation of ERK1/2 (extracellular regulated kinase); whereas angiotensin II induced activation of CREB was accompanied by activation of ERK1/2. In chronic ethanol-binge studies, analysis of the whole cell extracts showed increased phosphorylation of CREB, with no effect on CREB protein levels; increased phospho-ERK1/2, and decreased phospho-p38 MAPK. In contrast, the nuclear levels of phospho-CREB and CREB protein were reduced. Reduction in phospho-CREB and CREB proteins in the nuclear extracts was accompanied by suppression of mRNA levels for CPT-1 (carnitine palmitoyl transferase-1) and increase in hepatic steatosis after binge. It is concluded that binge ethanol causes defect in the nuclear accumulation of CREB protein, phospho-CREB, and an exaggerated hepatic steatosis. These in vivo effects are distinct from the effects of ethanol on hepatocytes in vitro.
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Affiliation(s)
- Annayya R Aroor
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO 65212, United States
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31
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Ramirez T, Tong M, Ayala CA, Monfils PR, McMillan PN, Zabala V, Wands JR, de la Monte SM. Structural Correlates of PPAR Agonist Rescue of Experimental Chronic Alcohol-Induced Steatohepatitis. ACTA ACUST UNITED AC 2012; 2. [PMID: 26339530 PMCID: PMC4554760 DOI: 10.4172/2161-0681.1000114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chronic alcoholic liver disease is associated with hepatic insulin resistance, inflammation, oxidative and ER stress, mitochondrial dysfunction, and DNA damage. Peroxisome-proliferator activated receptor (PPAR) agonists are insulin sensitizers that have anti-inflammatory/anti-oxidant effects. We previously showed that PPAR agonists can restore hepatic insulin responsiveness in chronic ethanol-fed rats with steatohepatitis. Herein, we furthered our investigations by characterizing the histological and ultrastructural changes mediated by PPAR agonist rescue of alcohol-induced steatohepatitis. Adult male Long Evans rats were pair fed with isocaloric liquid diets containing 0% or 37% ethanol (caloric) for 8 weeks. After 3 weeks on the diets, rats were treated with vehicle, or a PPAR-α, PPAR-δ, or PPAR-γ agonist twice weekly by i.p. injection. Ethanol-fed rats developed steatohepatitis with disordered hepatic chord architecture, mega-mitochondria, disruption of the RER, increased apoptosis, and increased 4-hydroxynonenal (HNE) and 3-nitrotyrosine (NTyr) immunoreactivity. PPAR-δ and PPAR-γ agonists reduced the severity of steatohepatitis, and restored the hepatic chord-like architectural, mitochondrial morphology, and RER organization, and the PPAR-δ agonist significantly reduced hepatic HNE. On the other hand, prominent RER tubule dilation, which could reflect ER stress, persisted in ethanol-exposed, PPAR-γ treated but not PPAR-δ treated livers. The PPAR-α agonist exacerbated both steatohepatitis and formation of mega-mitochondria, and it failed to restore RER architecture or lower biochemical indices of oxidative stress. In conclusion, improved hepatic insulin responsiveness and decreased inflammation resulting from PPAR-δ or PPAR-γ agonist treatments of alcohol-induced steatohepatitis are likely mediated by enhanced signaling through metabolic pathways with attendant reductions in ER stress, oxidative stress, and mitochondrial dysfunction.
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Affiliation(s)
- Teresa Ramirez
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Ming Tong
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Carol A Ayala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul R Monfils
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Paul N McMillan
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Valerie Zabala
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Jack R Wands
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
| | - Suzanne M de la Monte
- Liver Research Center and Departments of Medicine, Pathology, Neurology, and Neurosurgery, Rhode Island Hospital and The Warren Alpert Medical School of Brown University, Providence, RI, USA
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Seth D, Haber PS, Syn WK, Diehl AM, Day CP. Pathogenesis of alcohol-induced liver disease: classical concepts and recent advances. J Gastroenterol Hepatol 2011; 26:1089-105. [PMID: 21545524 DOI: 10.1111/j.1440-1746.2011.06756.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alcoholic liver disease (ALD) is a primary consequence of heavy and prolonged drinking. ALD contributes to the bulk of liver disease burden worldwide. Progression of ALD is a multifactorial and multistep process that includes many genetic and environmental risk factors. The molecular pathogenesis of ALD involves alcohol metabolism and secondary mechanisms such as oxidative stress, endotoxin, cytokines and immune regulators. The histopathological manifestation of ALD occurs as an outcome of complex but controlled interactions between hepatic cell types. Hepatic stellate cells (HSCs) are the key drivers of fibrogenesis, but transformation of hepatocytes to myofibroblastoids also implicate parenchymal cells as playing an active role in hepatic fibrogenesis. Recent discoveries indicate that lipogenesis during the early stages of ALD is a risk for advancement to cirrhosis. Other recently identified novel molecules and physiological/cell signaling pathways include fibrinolysis, osteopontin, transforming growth factor-β-SMAD and hedgehog signaling, and involvement of novel cytokines in hepatic fibrogenesis. The observation that ALD and non-alcoholic steatohepatitis share common pathways and genetic polymorphisms suggests operation of parallel pathogenic mechanisms. Future research involving genomics, epigenomics, deep sequencing and non-coding regulatory elements holds promise to identify novel diagnostic and therapeutic targets for ALD. There is also a need for adequate animal models to study pathogenic mechanisms at the molecular level and targeted therapy.
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Affiliation(s)
- Devanshi Seth
- Drug Health Services, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
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Morán-Salvador E, López-Parra M, García-Alonso V, Titos E, Martínez-Clemente M, González-Périz A, López-Vicario C, Barak Y, Arroyo V, Clària J. Role for PPARγ in obesity-induced hepatic steatosis as determined by hepatocyte- and macrophage-specific conditional knockouts. FASEB J 2011; 25:2538-50. [PMID: 21507897 DOI: 10.1096/fj.10-173716] [Citation(s) in RCA: 299] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Peroxisome proliferator-activated receptor (PPAR) γ is a nuclear receptor central to glucose and lipid homeostasis. PPARγ role in nonalcoholic fatty liver disease is controversial because PPARγ overexpression is a general property of steatotic livers, but its activation by thiazolidinediones reduces hepatic steatosis. Here, we investigated hepatic PPARγ function by using Cre-loxP technology to generate hepatocyte (PPARγ(Δhep))- and macrophage (PPARγ(Δmac))-specific PPARγ-knockout mice. Targeted deletion of PPARγ in hepatocytes, and to a lesser extent in macrophages, protected mice against high-fat diet-induced hepatic steatosis. Down-regulated expression of genes involved in lipogenesis (SCD1, SREBP-1c, and ACC), lipid transport (CD36/FAT, L-FABP, and MTP), and β-oxidation (PPARα and ACO) was observed in PPARγ(Δhep) mice. Moreover, PPARγ(Δhep) mice showed improved glucose tolerance and reduced PEPCK expression without changes in Pcx, Fbp1, and G6Pc expression and CREB and JNK phosphorylation. In precision-cut liver slices (PCLSs) and hepatocytes, rosiglitazone either alone or in combination with oleic acid increased triglyceride accumulation, an effect that was blocked by the PPARγ antagonist biphenol A diglycidyl ether (BADGE). PCLSs and hepatocytes from PPARγ(Δhep) mice showed blunted responses to rosiglitazone and oleic acid, whereas the response to these compounds remained intact in PCLSs from PPARγ(Δmac) mice. Collectively, these findings establish PPARγ expression in hepatocytes as a prosteatotic factor in fatty liver disease.
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Affiliation(s)
- Eva Morán-Salvador
- Department of Biochemistry and Molecular Genetics, Hospital Clínic, Esther Koplowitz Center–Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain
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Xu P, Xu K, Wang J, Jiang JP, Chen LQ. Pioglitazone: a promising therapeutic tool in sodium taurocholate-induced severe acute pancreatitis. Dig Dis Sci 2011; 56:1082-9. [PMID: 20824499 DOI: 10.1007/s10620-010-1393-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/11/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND Studies suggest that peroxisome proliferator-activated receptor γ(PPARγ) ligands may represent a therapeutic option in acute pancreatitis, yet most of them have been prophylactic administrated. AIMS To evaluate the therapeutic effect of pioglitazone in rats with severe acute pancreatitis induced by sodium taurocholate. METHODS Severe acute pancreatitis (SAP) was induced in male Sprague-Dawley rats by the retrograde injection of 5% sodium taurocholate into the pancreatic duct. After SAP was induced, pioglitazone was injected intraperitoneally and its role on the severity of inflammatory response and pancreatic injury was investigated. Amylase activity, inflammatory cytokines production, pathological changes of pancreas, PPARγ mRNA expression, and the survival rate were examined. RESULTS Treatment with pioglitazone decreased the level of amylase activity, proinflammatory factors IL-6 and TNF-α, ameliorated pancreatic histological score, and upregulated the expression of PPARγ mRNA. The survival rate in the early stage of severe acute pancreatitis was also improved. CONCLUSIONS Pioglitazone can be used as a therapeutic drug and relieve the damages caused by SAP, which suggests PPARγ ligand-pioglitazone offers a potent approach for the treatment of severe acute pancreatitis.
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Affiliation(s)
- Ping Xu
- Department of Gastroenterology, Branch Hospital of the First People's Hospital, Shanghai Jiao Tong University, School of Medicine, 201600, Shanghai, China.
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Kursawe R, Narayan D, Cali AM, Shaw M, Pierpont B, Shulman GI, Caprio S. Downregulation of ADIPOQ and PPARγ2 gene expression in subcutaneous adipose tissue of obese adolescents with hepatic steatosis. Obesity (Silver Spring) 2010; 18:1911-7. [PMID: 20168312 PMCID: PMC3898705 DOI: 10.1038/oby.2010.23] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hepatic steatosis is associated with hypoadiponectinemia. The mechanism(s) resulting in lower serum adiponectin levels in obese adolescents with fatty liver is unknown. In two groups of equally obese adolescents, but discordant for hepatic fat content, we measured adiponectin, leptin, peroxisome proliferator-activated receptor γ 2 (PPARγ2) and tumor necrosis factor-α (TNFα) gene expression in the abdominal subcutaneous adipose tissue (SAT). Twenty six adolescents with similar degrees of obesity underwent a subcutaneous periumbilical adipose tissue biopsy, in addition to metabolic (oral glucose tolerance test, and hyperinsulinemic--euglycemic clamp), and imaging studies (magnetic resonance imaging (MRI), DEXA). Using quantitative real-time-PCR; adiponectin, PPARγ2, TNFα, and leptin mRNA were measured. Based on a hepatic fat content (hepatic fat fraction, HFF) >5.5%, measured by fast MRI, the subjects were divided into low and high HFF group. In addition to the hypoadiponectinemia in the high HFF group, we found that the expression of adiponectin as well as PPARγ2 in the SAT was significantly decreased in this group. No differences were noted for TNFα and leptin plasma or mRNA levels between the groups. An inverse relationship was observed between adiponectin or PPARγ2 expression and hepatic fat content, whereas, adiponectin expression was positively related to PPARγ2 expression. Independent of overall obesity, a reduced expression of adiponectin and PPARγ2 in the abdominal SAT is associated with high liver fat content, as well as with insulin resistance in obese adolescents.
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Affiliation(s)
- Romy Kursawe
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Deepak Narayan
- Department of Plastic Surgery, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Anna M.G. Cali
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Melissa Shaw
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Bridget Pierpont
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sonia Caprio
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut, USA
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Toll-like receptors in the pathogenesis of alcoholic liver disease. Gastroenterol Res Pract 2010; 2010. [PMID: 20827314 PMCID: PMC2933900 DOI: 10.1155/2010/710381] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Accepted: 07/20/2010] [Indexed: 12/15/2022] Open
Abstract
In the multifactorial pathophysiology of alcoholic liver disease (ALD), inflammatory cascade activation plays a central role. Recent studies demonstrated that Toll-like Receptors, the sensors of microbial and endogenous danger signals, are expressed and activated in innate immune cells as well as in parenchymal cells in the liver and thereby contribute to ALD. In this paper, we discuss the importance of gut-derived endotoxin and its recognition by TLR4. The significance of TLR-induced intracellular signaling pathways and cytokine production as well as the contribution of reactive oxygen radicals is evaluated. The contribution of TLR signaling to induction of liver fibrosis and hepatocellular cancer is reviewed in the context of alcohol-induced liver disease.
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Gyamfi MA, Wan YJY. Pathogenesis of alcoholic liver disease: the role of nuclear receptors. Exp Biol Med (Maywood) 2010; 235:547-60. [PMID: 20463294 DOI: 10.1258/ebm.2009.009249] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Ethanol consumption causes fatty liver, which can lead to inflammation, fibrosis, cirrhosis and even liver cancer. The molecular mechanisms by which ethanol exerts its damaging effects are extensively studied, but not fully understood. It is now evident that nuclear receptors (NRs), including retinoid x receptor alpha and peroxisome proliferator-activated receptors, play key roles in the regulation of lipid homeostasis and inflammation during the pathogenesis of alcoholic liver disease (ALD). Given their pivotal roles in physiological processes, NRs represent potential therapeutic targets for the treatment and prevention of numerous metabolic and lipid-related diseases including ALD. This review summarizes the factors that contribute to ALD and the molecular mechanisms of ALD with a focus on the role of NRs.
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Affiliation(s)
- Maxwell Afari Gyamfi
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, Kansas 66160-7417, USA
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Bae MA, Rhee SD, Jung WH, Ahn JH, Song BJ, Cheon HG. Selective inhibition of activated stellate cells and protection from carbon tetrachloride-induced liver injury in rats by a new PPARgamma agonist KR62776. Arch Pharm Res 2010; 33:433-42. [PMID: 20361309 PMCID: PMC3835440 DOI: 10.1007/s12272-010-0313-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 11/23/2009] [Accepted: 01/07/2010] [Indexed: 12/23/2022]
Abstract
Activated hepatic stellate cells (HSC) are the primary source of extracellular matrix proteins found in liver fibrosis/cirrhosis patients. Therefore, the prevention of HSC activation is an important strategy for treating severe liver injury. This study examined the effects of KR62776, a new peroxisome proliferator-activated receptor gamma (PPARgamma) agonist, on the rate of cell proliferation and expression of alpha-smooth muscle actin (alpha-SMA) in rat hepatic stellate HSC-T6 cells. In addition, its effects on the liver damage induced by carbon tetrachloride were investigated. KR62776 caused the apoptosis of activated HSC-T6 cells with the concomitant decrease in the alpha-smooth muscle actin levels in a time- and concentration-dependent manner. However, KR62776 did not cause the apoptosis of human HepG2 and rat McARH7777 hepatoma cells, suggesting that KR62776 has a specific effect on stellate cells. KR62776 increased the levels of Gadd45, p27, p21 and PPARgamma proteins but decreased the cell cyclerelated proteins, such as cdk2, cyclin B and cyclin D1. These changes were reversed by BADGE, a specific PPARgamma antagonist, indicating that the effects of KR62776 are, at least in part, PPARgamma-dependent. In addition, KR62776 administration showed some protection against carbon tetrachloride-induced hepatocellular damage in rats. Overall, these results suggest that KR62776 may have potential in the chemoprevention of liver fibrosis/cirrhosis.
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Affiliation(s)
- Myung-Ae Bae
- Drug Discovery Platform Technology Team, Medicinal Science Division, Korea Research Institute of Chemical Technology, Daejon, 305-600, Korea.
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Moyes KM, Drackley JK, Morin DE, Bionaz M, Rodriguez-Zas SL, Everts RE, Lewin HA, Loor JJ. Gene network and pathway analysis of bovine mammary tissue challenged with Streptococcus uberis reveals induction of cell proliferation and inhibition of PPARgamma signaling as potential mechanism for the negative relationships between immune response and lipid metabolism. BMC Genomics 2009; 10:542. [PMID: 19925655 PMCID: PMC2784807 DOI: 10.1186/1471-2164-10-542] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 11/19/2009] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Information generated via microarrays might uncover interactions between the mammary gland and Streptococcus uberis (S. uberis) that could help identify control measures for the prevention and spread of S. uberis mastitis, as well as improve overall animal health and welfare, and decrease economic losses to dairy farmers. The main objective of this study was to determine the most affected gene networks and pathways in mammary tissue in response to an intramammary infection (IMI) with S. uberis and relate these with other physiological measurements associated with immune and/or metabolic responses to mastitis challenge with S. uberis O140J. RESULTS Streptococcus uberis IMI resulted in 2,102 (1,939 annotated) differentially expressed genes (DEG). Within this set of DEG, we uncovered 20 significantly enriched canonical pathways (with 20 to 61 genes each), the majority of which were signaling pathways. Among the most inhibited were LXR/RXR Signaling and PPARalpha/RXRalpha Signaling. Pathways activated by IMI were IL-10 Signaling and IL-6 Signaling which likely reflected counter mechanisms of mammary tissue to respond to infection. Of the 2,102 DEG, 1,082 were up-regulated during IMI and were primarily involved with the immune response, e.g., IL6, TNF, IL8, IL10, SELL, LYZ, and SAA3. Genes down-regulated (1,020) included those associated with milk fat synthesis, e.g., LPIN1, LPL, CD36, and BTN1A1. Network analysis of DEG indicated that TNF had positive relationships with genes involved with immune system function (e.g., CD14, IL8, IL1B, and TLR2) and negative relationships with genes involved with lipid metabolism (e.g., GPAM, SCD, FABP4, CD36, and LPL) and antioxidant activity (SOD1). CONCLUSION Results provided novel information into the early signaling and metabolic pathways in mammary tissue that are associated with the innate immune response to S. uberis infection. Our study indicated that IMI challenge with S. uberis (strain O140J) elicited a strong transcriptomic response, leading to potent activation of pro-inflammatory pathways that were associated with a marked inhibition of lipid synthesis, stress-activated kinase signaling cascades, and PPAR signaling (most likely PPARgamma). This latter effect may provide a mechanistic explanation for the inverse relationship between immune response and milk fat synthesis.
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Affiliation(s)
- Kasey M Moyes
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
- Aarhus University, Faculty of Agricultural Sciences, Research Centre Foulum, PO Box 50, DK-8830 Tjele, Denmark
| | - James K Drackley
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
| | - Dawn E Morin
- College of Veterinary Medicine, University of Illinois, 2001 South Lincoln Avenue, Urbana, 61802, USA
| | - Massimo Bionaz
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
| | - Sandra L Rodriguez-Zas
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
| | - Robin E Everts
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
- Sequenom, Inc, 3595 John Hopkins Court, San Diego, CA 92121, USA
| | - Harris A Lewin
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
- Institute for Genomic Biology, University of Illinois, 1206 West Gregory Drive, Urbana, 61801, USA
| | - Juan J Loor
- Department of Animal Sciences, University of Illinois, 1207 West Gregory Drive, Urbana, 61801, USA
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Peroxisome proliferator-activated receptor and retinoic x receptor in alcoholic liver disease. PPAR Res 2009; 2009:748174. [PMID: 19756185 PMCID: PMC2743826 DOI: 10.1155/2009/748174] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2009] [Revised: 05/19/2009] [Accepted: 07/13/2009] [Indexed: 12/13/2022] Open
Abstract
A growing number of new studies demonstrate that nuclear receptors are involved in the development of alcoholic liver disease (ALD). Ethanol metabolism and RXR/PPAR functions are tightly interconnected in the liver. Several ethanol metabolizing enzymes are potently regulated by RXR and PPARα after alcohol consumption. The increased ethanol metabolism, in turn, leads to alteration of the redox balance of the cells and impairment of RXR/PPAR functions by direct and indirect effects of acetaldehyde, resulting in deranged lipid metabolism, oxidative stress, and release of proinflammatory cytokines. The use of animal models played a crucial role in understanding the molecular mechanisms of ALD. In this paper we summarize the reciprocal interactions between ethanol metabolism and RXR/PPAR functions. In conclusion, RXR and PPAR play a central role in the onset and perpetuation of the mechanisms underling all steps of the clinical progression in ALD.
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Marcos M, Pastor I, González-Sarmiento R, Laso FJ. A functional polymorphism of the NFKB1 gene increases the risk for alcoholic liver cirrhosis in patients with alcohol dependence. Alcohol Clin Exp Res 2009; 33:1857-62. [PMID: 19673747 DOI: 10.1111/j.1530-0277.2009.01023.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND The genetic basis for the predisposition to alcoholic liver cirrhosis (ALC) remains unknown. Increasing evidence supports a role for the nuclear factor (NF)-kappaB, the NF-kappaB inhibitor alpha (NFKBIA), and the peroxisome proliferator-activated receptor (PPAR)-gamma in the pathogenesis of alcoholic liver disease, raising the possibility that common polymorphisms in genes encoding these molecules may confer susceptibility to ALC. The objective of this study was to analyze the relationship between common polymorphisms in NFKB1, NFKBIA, and PPARG2 genes and the presence of ALC. METHODS A total of 258 male alcoholics (161 without liver disease and 97 with ALC) and 101 healthy controls were genotyped for the -94ins/delATTG NFKB1, 3'-UTR+126G>A NFKBIA, and 34C>G PPARG2 polymorphisms. The association of these genetic variants with ALC was tested in alcoholic patients with alcohol abuse and alcohol dependence. A logistic regression analysis was further performed to analyze the model of inheritance. RESULTS We found an association between the presence of the deletion allele in NFKB1 polymorphism and ALC in patients with alcohol dependence. We found no association between NFKBIA and PPARG2 polymorphisms and the presence of ALC. CONCLUSIONS The deletion allele of the -94ins/del NFKB1 polymorphism could be associated with a higher risk of developing ALC through an increase in inflammation, as supported by previous data.
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Affiliation(s)
- Miguel Marcos
- The Unidad de Alcoholismo, Servicio de Medicina Interna II, Hospital Universitario de Salamanca, Spain
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de la Monte SM, Longato L, Tong M, DeNucci S, Wands JR. The liver-brain axis of alcohol-mediated neurodegeneration: role of toxic lipids. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2009; 6:2055-75. [PMID: 19742171 PMCID: PMC2738898 DOI: 10.3390/ijerph6072055] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 07/16/2009] [Indexed: 12/12/2022]
Abstract
Alcohol abuse causes progressive toxicity and degeneration in liver and brain due to insulin resistance, which exacerbates oxidative stress and pro-inflammatory cytokine activation. Alcohol-induced steatohepatitis promotes synthesis and accumulation of ceramides and other toxic lipids that cause insulin resistance. Ceramides can readily cross the blood-brain barrier, and ceramide exposure causes neurodegeneration with insulin resistance and oxidative stress, similar to the effects of alcohol. Therefore, in addition to its direct neurotoxic effects, alcohol misuse establishes a liver-brain axis of neurodegeneration mediated by toxic lipid trafficking across the blood-brain barrier, leading to progressive white matter degeneration and cognitive impairment.
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Abstract
Alcoholic fatty liver is a major risk factor for advanced liver injuries such as steatohepatitis, fibrosis, and cirrhosis. While the underlying mechanisms are multiple, the development of alcoholic fatty liver has been attributed to a combined increase in the rate of de novo lipogenesis and a decrease in the rate of fatty acid oxidation in animal liver. Among various transcriptional regulators, the hepatic SIRT1 (sirtuin 1)-AMPK (AMPK-activated kinase) signaling system represents a central target for the action of ethanol in the liver. Adiponectin is one of the adipocyte-derived adipokines with potent lipid-lowering properties. Growing evidence has demonstrated that the development of alcoholic fatty liver is associated with reduced circulating adiponectin levels, decreased hepatic adiponectin receptor expression, and impaired hepatic adiponectin signaling. Adiponectin confers protection against alcoholic fatty liver via modulation of complex hepatic signaling pathways largely controlled by the central regulatory system, SIRT1-AMPK axis. This review aims to integrate the current research findings of ethanol-mediated dysregulation of adiponectin and its receptors and to provide a comprehensive point of view for understanding the role of adiponectin signaling in the development of alcoholic fatty liver.
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Affiliation(s)
- Min You
- Department of Molecular Pharmacology and Physiology, School of Basic Biomedical Sciences, College of Medicine, Box 8, University of South Florida, Tampa, FL 33612, USA.
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Aoyama T, Ikejima K, Kon K, Okumura K, Arai K, Watanabe S. Pioglitazone promotes survival and prevents hepatic regeneration failure after partial hepatectomy in obese and diabetic KK-A(y) mice. Hepatology 2009; 49:1636-44. [PMID: 19205029 DOI: 10.1002/hep.22828] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
UNLABELLED Pathogenesis of metabolic syndrome-related nonalcoholic steatohepatitis (NASH) involves abnormal tissue-repairing responses in the liver. We investigated the effect of pioglitazone, a thiazolidinedione derivative (TZD), on hepatic regenerative responses in obese, diabetic KK-A(y) mice. Male KK-A(y) mice 9 weeks after birth underwent two-thirds partial hepatectomy (PH) after repeated intragastric injections of pioglitazone (25 mg/kg) for 5 days. Almost half of the KK-A(y) mice died within 48 hours of PH;however, mortality was completely prevented in mice pretreated with pioglitazone. In KK-A(y) mice, bromodeoxyuridine (BrdU) incorporation to hepatocyte nuclei 48 hours after PH reached only 1%; however, pioglitazone pretreatment significantly increased BrdU-positive cells to 8%. Cyclin D1 was barely detectable in KK-A(y) mice within 48 hours after PH. In contrast, overt expression of cyclin D1 was observed 24 hours after PH in KK-A(y) mice pretreated with pioglitazone. Hepatic tumor necrosis factor alpha (TNF-alpha) messenger RNA (mRNA) was tremendously increased 1 hour after PH in KK-A(y) mice, the levels reaching ninefold over C57Bl/6 given PH, whereas pioglitazone blunted this increase by almost three-fourths. Pioglitazone normalized hypoadiponectinemia in KK-A(y) mice almost completely. Serum interleukin (IL)-6 and leptin levels were elevated extensively 24 hours after PH in KK-A(y) mice, whereas the levels were largely decreased in KK-A(y) mice given pioglitazone. Indeed, pioglitazone prevented aberrant increases in signal transducers and activators of transcription (STAT)3 phosphorylation and suppressor of cytokine signaling (SOCS)-3 mRNA in the liver in KK-A(y) mice. CONCLUSION These findings indicated that pioglitazone improved hepatic regeneration failure in KK-A(y) mice. The mechanism underlying the effect of pioglitazone on regeneration failure most likely involves normalization of expression pattern of adipokines and subsequent cytokine responses during the early stage of PH.
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Affiliation(s)
- Tomonori Aoyama
- Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan
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Abstract
Worldwide, one of the most prevalent forms of chronic disease is alcoholic fatty liver, which may progress to more severe forms of liver injury including steatohepatitis, fibrosis, and cirrhosis. The molecular mechanisms by which ethanol consumption causes accumulation of hepatic lipid are multiple and complex. Chronic ethanol exposure is thought to cause enhanced hepatic lipogenesis and impaired fatty acid oxidation by inhibiting key hepatic transcriptional regulators such as AMP-activated kinase (AMPK), sirtuin 1 (SIRT1), PPAR-gamma coactivator alpha (PGC-1alpha), peroxisome proliferator-activated receptor alpha (PPARalpha), and sterol regulatory element-binding protein 1 (SREBP-1). Adiponectin is an adipose-derived hormone with a variety of beneficial biological functions. Increasing evidence suggests that altered adiponectin production in adipose tissue and impaired expression of hepatic adiponectin receptors (AdipoRs) are associated with the development of alcoholic liver steatosis in several rodent models. More importantly, studies have demonstrated a protective role of adiponectin against alcoholic liver steatosis. The hepato-protective effect of adiponectin is largely mediated by the coordination of multiple signaling pathways in the liver, leading to enhanced fat oxidation, reduced lipid synthesis and prevention of hepatic steatosis. This review begins with an assessment of the current understanding of the role of adiponectin and its receptors in the regulation of lipid homeostasis in liver, with emphasis on their relationship to the development of alcoholic liver steatosis. Following sections will review hepatic signaling molecules involved in the protective actions of adiponectin against alcoholic fatty liver and summarize the current knowledge of regulatory mechanisms of adiponectin expression and secretion in response to chronic ethanol exposure. We will conclude with a discussion of potential strategies for treating human alcoholic fatty liver disease (AFLD), including nutritional and pharmacological modulation of adiponectin and its receptors.
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Affiliation(s)
- Christopher Q Rogers
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center,Tampa, FL 33612, USA
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Sun F, Xie ML, Zhu LJ, Xue J, Gu ZL. Inhibitory effect of osthole on alcohol-induced fatty liver in mice. Dig Liver Dis 2009; 41:127-33. [PMID: 18339590 DOI: 10.1016/j.dld.2008.01.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Revised: 01/22/2008] [Accepted: 01/30/2008] [Indexed: 02/08/2023]
Abstract
BACKGROUND Alcohol is a major cause of fatty liver, the disease is a spectrum that is initiated with steatosis, and without therapy it is apt to develop inflammation, necrosis, fibrosis and finally cirrhosis. There are currently no ideal pharmacological reagents that can prevent or reverse this disease. Osthole is an active constituent isolated from the fruit of Cnidium monnieri (L.) Cusson, a Chinese herbal medicine, which has been used in clinics for many years. It has many functions such as anti-inflammation, anti-osteoporosis and anti-tumor and so on, but there is no report about treatment of alcoholic fatty liver in mice. AIM To examine the inhibitory effect of osthole on alcohol-induced fatty liver in mice and to investigate the potential mechanisms. METHODS A mouse model with alcoholic fatty liver was induced by orally feeding 52% erguotou wine by gavage when they were simultaneously treated with osthole 10, 20, 40 mg/kg for 4 weeks. Whereafter, the lipids in serum and hepatic tissue, the levels of malondialdehyde (MDA), superoxide dismutase (SOD), reduced glutathione hormone (GSH), tumor necrosis factor-alpha (TNF-alpha) in hepatic tissue, hepatic weight coefficient and its histological evaluation were measured. RESULTS After treatment with osthole, the levels of serum total cholesterol (TC), triglyceride (TG), coefficient of hepatic weight, and the hepatic tissue contents of TC and TG were significantly decreased, the levels of MDA and TNF-alpha in liver were also decreased, while the GSH in liver was increased. Importantly, the histological evaluation of liver specimens demonstrated that osthole dramatically decreased lipid accumulation. CONCLUSION Osthole could inhibit alcohol-induced fatty liver in mice, and the mechanism might be associated with its anti-oxidation and suppression of TNF-alpha production.
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Affiliation(s)
- F Sun
- Department of Pharmacology, Medical School of Soochow University, Suzhou 215123, Jiangsu Province, China
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Abstract
Non-alcoholic fatty liver disease or NAFLD is a chronic liver condition characterized by hepatic steatosis and associated with insulin resistance and type 2 diabetes mellitus (T2DM). In many patients fat accumulation leads to steatohepatitis (NASH) with chronic necrosis, inflammation, and fibrosis, and eventually to the development of cirrhosis. Obese and T2DM patients are at the greatest risk for NASH and progressive disease. New diagnostic techniques, such as magnetic resonance imaging and spectroscopy (MRS), have enhanced our way to non-invasively quantify liver fat and suggest that the epidemic of NAFLD is much larger than previously believed. However, the diagnosis of NAFLD for clinicians remains difficult due to a number of factors: limited awareness, non-specific symptoms, few laboratory findings, and the need for a liver biopsy to confirm the diagnosis. Traditional treatment approaches have centered on weight loss, but data are limited on its long-term efficacy, and the overall compliance is poor. Recently, pioglitazone has been shown to be safe and effective in patients with NASH and may radically change our approach to the disease. Still, many aspects remain poorly understood. Taken together, wider use of new diagnostic methods and treatment approaches appears to signal the dawn of a new era in the management of NAFLD.
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Affiliation(s)
- Rafeeq Ali
- Endocrinology Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78284-3900, USA
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Abstract
Alcoholic fatty liver is a potentially pathologic condition which can progress to steatohepatitis, fibrosis, and cirrhosis if alcohol consumption is continued. Alcohol exposure may induce fatty liver by increasing NADH/NAD(+) ratio, increasing sterol regulatory element-binding protein-1 (SREBP-1) activity, decreasing peroxisome proliferator-activated receptor-alpha (PPAR-alpha) activity, and increasing complement C3 hepatic levels. Alcohol may increase SREBP-1 activity by decreasing the activities of AMP-activated protein kinase and sirtuin-1. Tumor necrosis factor-alpha (TNF-alpha) produced in response to alcohol exposure may cause fatty liver by up-regulating SREBP-1 activity, whereas betaine and pioglitazone may attenuate fatty liver by down-regulating SREBP-1 activity. PPAR-alpha agonists have potentials to attenuate alcoholic fatty liver. Adiponectin and interleukin-6 may attenuate alcoholic fatty liver by up-regulating PPAR-alpha and insulin signaling pathways while down-regulating SREBP-1 activity and suppressing TNF-alpha production. Recent studies show that paracrine activation of hepatic cannabinoid receptor 1 by hepatic stellate cell-derived endocannabinoids also contributes to the development of alcoholic fatty liver. Furthermore, oxidative modifications and inactivation of the enzymes involved in the mitochondrial and/or peroxisomal beta-oxidation of fatty acids could contribute to fat accumulation in the liver.
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Affiliation(s)
- Vishnudutt Purohit
- Division of Metabolism and Health Effects, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 5635 Fishers Lane, Bethesda, MD 20892, USA.
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Ajmo JM, Liang X, Rogers CQ, Pennock B, You M. Resveratrol alleviates alcoholic fatty liver in mice. Am J Physiol Gastrointest Liver Physiol 2008; 295:G833-42. [PMID: 18755807 PMCID: PMC2575919 DOI: 10.1152/ajpgi.90358.2008] [Citation(s) in RCA: 288] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alcoholic fatty liver is associated with inhibition of sirtuin 1 (SIRT1) and AMP-activated kinase (AMPK), two critical signaling molecules regulating the pathways of hepatic lipid metabolism in animals. Resveratrol, a dietary polyphenol, has been identified as a potent activator for both SIRT1 and AMPK. In the present study, we have carried out in vivo animal experiments that test the ability of resveratrol to reverse the inhibitory effects of chronic ethanol feeding on hepatic SIRT1-AMPK signaling system and to prevent the development of alcoholic liver steatosis. Resveratrol treatment increased SIRT1 expression levels and stimulated AMPK activity in livers of ethanol-fed mice. The resveratrol-mediated increase in activities of SIRT1 and AMPK was associated with suppression of sterol regulatory element binding protein 1 (SREBP-1) and activation of peroxisome proliferator-activated receptor gamma coactivator alpha (PGC-1alpha). In parallel, in ethanol-fed mice, resveratrol administration markedly increased circulating adiponectin levels and enhanced mRNA expression of hepatic adiponectin receptors (AdipoR1/R2). In conclusion, resveratrol treatment led to reduced lipid synthesis and increased rates of fatty acid oxidation and prevented alcoholic liver steatosis. The protective action of resveratrol is in whole or in part mediated through the upregulation of a SIRT1-AMPK signaling system in the livers of ethanol-fed mice. Our study suggests that resveratrol may serve as a promising agent for preventing or treating human alcoholic fatty liver disease.
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Affiliation(s)
- Joanne M. Ajmo
- Departments of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, Tampa, Florida
| | - Xiaomei Liang
- Departments of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, Tampa, Florida
| | - Christopher Q. Rogers
- Departments of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, Tampa, Florida
| | - Brandi Pennock
- Departments of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, Tampa, Florida
| | - Min You
- Departments of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, Tampa, Florida
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de la Monte SM, Yeon JE, Tong M, Longato L, Chaudhry R, Pang MY, Duan K, Wands JR. Insulin resistance in experimental alcohol-induced liver disease. J Gastroenterol Hepatol 2008; 23:e477-86. [PMID: 18505416 PMCID: PMC10012390 DOI: 10.1111/j.1440-1746.2008.05339.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIM Chronic ethanol consumption impairs liver regeneration due, in part, to inhibition of insulin signaling. This study characterizes the mechanisms and consequences of ethanol-impaired insulin signaling in relation to oxidative injury and altered gene expression. METHODS Long-Evans rats were fed for 8 weeks with isocaloric liquid diets containing 0% (control) or 37% ethanol (caloric content). Livers were used to examine histopathology, indices of oxidative stress, gene expression required for insulin and insulin-like growth factor (IGF) signaling, insulin-responsive gene expression, i.e. glyceraldehydes-3-phosphate dehydrogenase (GAPDH) and aspartyl-asparaginyl-beta-hydroxylase (AAH), and competitive equilibrium binding to the insulin, IGF-I, and IGF-II receptors. RESULTS Chronic ethanol exposure caused liver injury with increased hepatocellular steatosis, inflammation, apoptosis, and increased immunoreactivity for activated caspase-3, 8-hydroxy-2'-deoxyguanosine, and 4-hydroxy-2,3-nonenol. These effects were associated with increased expression of IGF-I receptor, IGF-II, and IGF-II receptor, and expression of IGF-I, AAH, and GAPDH, which mediate energy metabolism and cell motility/remodeling, and reduced binding to the insulin receptor. CONCLUSIONS Chronic ethanol-induced liver injury causes insulin resistance with inhibition of insulin-responsive genes needed for metabolism, remodeling, and regeneration. In contrast, the IGF-I and IGF-II signaling mechanisms remain relatively preserved, suggesting that insulin-regulated hepatic functions may be selectively vulnerable to the toxic effects of ethanol.
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Affiliation(s)
- Suzanne M de la Monte
- Departments of Medicine, Liver Research Center, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA.
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