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Koppe SWP. Obesity and the liver: nonalcoholic fatty liver disease. Transl Res 2014; 164:312-22. [PMID: 25028077 DOI: 10.1016/j.trsl.2014.06.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/18/2014] [Accepted: 06/19/2014] [Indexed: 02/08/2023]
Abstract
The increasing prevalence of nonalcoholic fatty liver disease (NAFLD) parallels the rise of obesity and its complications. NAFLD is a common cause of cirrhosis and a leading indication for liver transplant. Genetic susceptibility, dietary composition, and exercise habits influence the development of NAFLD, and insulin resistance results in widespread metabolic perturbations with a net effect of triglyceride accumulation in the liver. Some patients will develop hepatocyte cellular injury and fibrosis of the liver, which can progress to cirrhosis and require liver transplant. Treatments targeting the pathophysiological mechanisms of NAFLD exist, but carry some potential risk and are not universally effective. Weight loss and lifestyle changes remain the most effective and safest approach, but sustainable change is difficult for most patients to achieve. Future work will continue to focus on developing effective and safe interventions to prevent the development of advanced liver disease, whereas efforts in the public health domain continue to combat obesity.
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Affiliation(s)
- Sean W P Koppe
- Division of Gastroenterology and Hepatology, Northwestern University, Chicago, Ill.
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Dranoff JA, Feld JJ, Lavoie ÉG, Fausther M. How does coffee prevent liver fibrosis? Biological plausibility for recent epidemiological observations. Hepatology 2014; 60:464-7. [PMID: 24464631 PMCID: PMC4110162 DOI: 10.1002/hep.27032] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 01/23/2014] [Indexed: 01/14/2023]
Affiliation(s)
- Jonathan A. Dranoff
- Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences
| | | | - Élise G. Lavoie
- Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences
| | - Michel Fausther
- Division of Gastroenterology and Hepatology, University of Arkansas for Medical Sciences
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53
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Nrf2 pathway activation contributes to anti-fibrosis effects of ginsenoside Rg1 in a rat model of alcohol- and CCl4-induced hepatic fibrosis. Acta Pharmacol Sin 2014; 35:1031-44. [PMID: 24976156 DOI: 10.1038/aps.2014.41] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 04/11/2014] [Indexed: 12/14/2022] Open
Abstract
AIM To investigate the anti-fibrosis effects of ginsenoside Rg1 on alcohol- and CCl4-induced hepatic fibrosis in rats and to explore the mechanisms of the effects. METHODS Rats were given 6% alcohol in water and injected with CCl4 (2 mL/kg, sc) twice a week for 8 weeks. Rg1 (10, 20 and 40 mg/kg per day, po) was administered in the last 2 weeks. Hepatic fibrosis was determined by measuring serum biochemical parameters, HE staining, Masson's trichromic staining, and hydroxyproline and α-SMA immunohistochemical staining of liver tissues. The activities of antioxidant enzymes, lipid peroxidation, and Nrf2 signaling pathway-related proteins (Nrf2, Ho-1 and Nqo1) in liver tissues were analyzed. Cultured hepatic stellate cells (HSCs) of rats were prepared for in vitro studies. RESULTS In the alcohol- and CCl4-treated rats, Rg1 administration dose-dependently suppressed the marked increases of serum ALT, AST, LDH and ALP levels, inhibited liver inflammation and HSC activation and reduced liver fibrosis scores. Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues. Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes. Treatment of the cultured HSCs with Rg1 (1 μmol/L) induced Nrf2 translocation, and suppressed CCl4-induced cell proliferation, reversed CCl4- induced changes in MDA, GPX, PCIII and HA contents in the supernatant fluid and α-SMA expression in the cells. Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro. CONCLUSION Rg1 exerts protective effects in a rat model of alcohol- and CCl4-induced hepatic fibrosis via promoting the nuclear translocation of Nrf2 and expression of antioxidant enzymes.
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54
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Roychowdhury S, Chiang DJ, McMullen MR, Nagy LE. Moderate, chronic ethanol feeding exacerbates carbon-tetrachloride-induced hepatic fibrosis via hepatocyte-specific hypoxia inducible factor 1α. Pharmacol Res Perspect 2014; 2:e00061. [PMID: 25089199 PMCID: PMC4115456 DOI: 10.1002/prp2.61] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The hypoxia-sensing transcriptional factor HIF1α is implicated in a variety of hepato-pathological conditions; however, the contribution of hepatocyte-derived HIF1α during progression of alcoholic liver injury is still controversial. HIF1α induces a variety of genes including those involved in apoptosis via p53 activation. Increased hepatocyte apoptosis is critical for progression of liver inflammation, stellate cell activation, and fibrosis. Using hepatocyte-specific HIF1α-deficient mice (ΔHepHIF1α−/−), here we investigated the contribution of HIF1α to ethanol-induced hepatocyte apoptosis and its role in amplification of fibrosis after carbon tetrachloride (CCl4) exposure. Moderate ethanol feeding (11% of kcal) induced accumulation of hypoxia-sensitive pimonidazole adducts and HIF1α expression in the liver within 4 days of ethanol feeding. Chronic CCl4 treatment increased M30-positive cells, a marker of hepatocyte apoptosis in pair-fed control mice. Concomitant ethanol feeding (11% of kcal) amplified CCl4-induced hepatocyte apoptosis in livers of wild-type mice, associated with elevated p53K386 acetylation, PUMA expression, and Ly6c+ cell infiltration. Subsequent to increased apoptosis, ethanol-enhanced induction of profibrotic markers, including stellate cell activation, collagen 1 expression, and extracellular matrix deposition following CCl4 exposure. Ethanol-induced exacerbation of hepatocyte apoptosis, p53K386 acetylation, and PUMA expression following CCl4 exposure was attenuated in livers of ΔHepHIF1α−/− mice. This protection was also associated with a reduction in Ly6c+ cell infiltration and decreased fibrosis in livers of ΔHepHIF1α−/− mice. In summary, these results indicate that moderate ethanol exposure leads to hypoxia/HIF1α-mediated signaling in hepatocytes and induction of p53-dependent apoptosis of hepatocytes, resulting in increased hepatic fibrosis during chronic CCl4 exposure.
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Affiliation(s)
- Sanjoy Roychowdhury
- Center for Liver Disease Research, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio
| | - Dian J Chiang
- Department of Gastroenterology, Cleveland Clinic, Cleveland, Ohio
| | - Megan R McMullen
- Center for Liver Disease Research, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio
| | - Laura E Nagy
- Center for Liver Disease Research, Department of Pathobiology, Cleveland Clinic, Cleveland, Ohio ; Department of Gastroenterology, Cleveland Clinic, Cleveland, Ohio ; Department of Molecular Medicine, Case Western Reserve University, Cleveland, Ohio
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55
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Wang H, Guan W, Yang W, Wang Q, Zhao H, Yang F, Lv X, Li J. Caffeine inhibits the activation of hepatic stellate cells induced by acetaldehyde via adenosine A2A receptor mediated by the cAMP/PKA/SRC/ERK1/2/P38 MAPK signal pathway. PLoS One 2014; 9:e92482. [PMID: 24682220 PMCID: PMC3969328 DOI: 10.1371/journal.pone.0092482] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/21/2014] [Indexed: 12/28/2022] Open
Abstract
Hepatic stellate cell (HSC) activation is an essential event during alcoholic liver fibrosis. Evidence suggests that adenosine aggravates liver fibrosis via the adenosine A2A receptor (A2AR). Caffeine, which is being widely consumed during daily life, inhibits the action of adenosine. In this study, we attempted to validate the hypothesis that caffeine influences acetaldehyde-induced HSC activation by acting on A2AR. Acetaldehyde at 50, 100, 200, and 400 μM significantly increased HSC-T6 cells proliferation, and cell proliferation reached a maximum at 48 h after exposure to 200 μM acetaldehyde. Caffeine and the A2AR antagonist ZM241385 decreased the cell viability and inhibited the expression of procollagen type I and type III in acetaldehyde-induced HSC-T6 cells. In addition, the inhibitory effect of caffeine on the expression of procollagen type I was regulated by A2AR-mediated signal pathway involving cAMP, PKA, SRC, and ERK1/2. Interestingly, caffeine’s inhibitory effect on the expression of procollagen type III may depend upon the A2AR-mediated P38 MAPK-dependent pathway. Conclusions: Caffeine significantly inhibited acetaldehyde-induced HSC-T6 cells activation by distinct A2AR mediated signal pathway via inhibition of cAMP-PKA-SRC-ERK1/2 for procollagen type I and via P38 MAPK for procollagen type III.
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Affiliation(s)
- He Wang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
| | - Wenjie Guan
- The 105th Hospital of PLA, Hefei, Anhui, China
| | - Wanzhi Yang
- The First Hospital of Anqing, Anqing, Anhui, China
| | - Qi Wang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
| | - Han Zhao
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
| | - Feng Yang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
| | - Xiongwen Lv
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
- * E-mail:
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, Anhui, China
- Institute for Liver Disease of Anhui Medical University, Hefei, Anhui, China
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Lenoir B, Wagner DR, Blacher S, Sala-Newby GB, Newby AC, Noel A, Devaux Y. Effects of adenosine on lymphangiogenesis. PLoS One 2014; 9:e92715. [PMID: 24651845 PMCID: PMC3961410 DOI: 10.1371/journal.pone.0092715] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 02/25/2014] [Indexed: 02/01/2023] Open
Abstract
Background The lymphatic system controls tissue homeostasis by draining protein-rich lymph to the vascular system. Lymphangiogenesis, the formation of lymphatic vessels, is a normal event in childhood but promotes tumor spread and metastasis during adulthood. Blocking lymphangiogenesis may therefore be of therapeutic interest. Production of adenosine is enhanced in the tumor environment and contributes to tumor progression through stimulation of angiogenesis. In this study, we determined whether adenosine affects lymphangiogenesis. Methods Lymphatic endothelial cells (HMVEC-dLy) were cultured in presence of adenosine and their proliferation, migration and tube formation was assessed. Gelatin sponges embedded with the stable analogue of adenosine 2-chloro adenosine were implanted in mice ear and lymphangiogenesis was quantified. Mice were intravenously injected with adenoviruses containing expression vector for 5′-endonucleotidase, which plays a major role in the formation of adenosine. Results In vitro, we observed that adenosine decreased the proliferation of lymphatic endothelial cells, their migration and tube formation. However, in vivo, gelatin sponges containing 2-chloro adenosine and implanted in mice ear displayed an elevated level of lymphangiogenesis (2.5-fold, p<0.001). Adenovirus-mediated over-expression of cytosolic 5′-nucleotidase IA stimulated lymphangiogenesis and the recruitment of macrophages in mouse liver. Proliferation of lymphatic endothelial cells was enhanced (2-fold, p<0.001) when incubated in the presence of conditioned medium from murine macrophages. Conclusion We have shown that adenosine stimulates lymphangiogenesis in vivo, presumably through a macrophage-mediated mechanism. This observation suggests that blockade of adenosine receptors may help in anti-cancer therapies.
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Affiliation(s)
- Bénédicte Lenoir
- Laboratory of Cardiovascular Research, Centre de Recherche Public de la Santé (CRP – Santé), Luxembourg
| | - Daniel R. Wagner
- Laboratory of Cardiovascular Research, Centre de Recherche Public de la Santé (CRP – Santé), Luxembourg
- Division of Cardiology, Centre Hospitalier Luxembourg, Luxembourg
| | - Silvia Blacher
- Laboratory of Tumor and Development Biology, Groupe Interdisciplinaire de Génoprotéomique Appliquée - Cancer, University of Liège, Liège, Belgium
| | - Graciela B. Sala-Newby
- Bristol Heart Institute, Bristol Royal Infirmary, University of Bristol, Bristol, United Kingdom
| | - Andrew C. Newby
- Bristol Heart Institute, Bristol Royal Infirmary, University of Bristol, Bristol, United Kingdom
| | - Agnès Noel
- Laboratory of Tumor and Development Biology, Groupe Interdisciplinaire de Génoprotéomique Appliquée - Cancer, University of Liège, Liège, Belgium
| | - Yvan Devaux
- Laboratory of Cardiovascular Research, Centre de Recherche Public de la Santé (CRP – Santé), Luxembourg
- * E-mail:
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Burnstock G, Vaughn B, Robson SC. Purinergic signalling in the liver in health and disease. Purinergic Signal 2014; 10:51-70. [PMID: 24271096 PMCID: PMC3944046 DOI: 10.1007/s11302-013-9398-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 10/24/2013] [Indexed: 12/18/2022] Open
Abstract
Purinergic signalling is involved in both the physiology and pathophysiology of the liver. Hepatocytes, Kupffer cells, vascular endothelial cells and smooth muscle cells, stellate cells and cholangiocytes all express purinoceptor subtypes activated by adenosine, adenosine 5'-triphosphate, adenosine diphosphate, uridine 5'-triphosphate or UDP. Purinoceptors mediate bile secretion, glycogen and lipid metabolism and indirectly release of insulin. Mechanical stress results in release of ATP from hepatocytes and Kupffer cells and ATP is also released as a cotransmitter with noradrenaline from sympathetic nerves supplying the liver. Ecto-nucleotidases play important roles in the signalling process. Changes in purinergic signalling occur in vascular injury, inflammation, insulin resistance, hepatic fibrosis, cirrhosis, diabetes, hepatitis, liver regeneration following injury or transplantation and cancer. Purinergic therapeutic strategies for the treatment of these pathologies are being explored.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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The significance of YKL-40 protein in liver fibrosis. Inflamm Res 2014; 63:249-54. [DOI: 10.1007/s00011-013-0698-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 11/30/2013] [Accepted: 12/04/2013] [Indexed: 12/15/2022] Open
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Lu D, Insel PA. Cellular mechanisms of tissue fibrosis. 6. Purinergic signaling and response in fibroblasts and tissue fibrosis. Am J Physiol Cell Physiol 2013; 306:C779-88. [PMID: 24352335 DOI: 10.1152/ajpcell.00381.2013] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Tissue fibrosis occurs as a result of the dysregulation of extracellular matrix (ECM) synthesis. Tissue fibroblasts, resident cells responsible for the synthesis and turnover of ECM, are regulated via numerous hormonal and mechanical signals. The release of intracellular nucleotides and their resultant autocrine/paracrine signaling have been shown to play key roles in the homeostatic maintenance of tissue remodeling and in fibrotic response post-injury. Extracellular nucleotides signal through P2 nucleotide and P1 adenosine receptors to activate signaling networks that regulate the proliferation and activity of fibroblasts, which, in turn, influence tissue structure and pathologic remodeling. An important component in the signaling and functional responses of fibroblasts to extracellular ATP and adenosine is the expression and activity of ectonucleotideases that attenuate nucleotide-mediated signaling, and thereby integrate P2 receptor- and subsequent adenosine receptor-initiated responses. Results of studies of the mechanisms of cellular nucleotide release and the effects of this autocrine/paracrine signaling axis on fibroblast-to-myofibroblast conversion and the fibrotic phenotype have advanced understanding of tissue remodeling and fibrosis. This review summarizes recent findings related to purinergic signaling in the regulation of fibroblasts and the development of tissue fibrosis in the heart, lungs, liver, and kidney.
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Affiliation(s)
- David Lu
- Department of Pharmacology, University of California, San Diego, La Jolla, California; and
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