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Machado SR, Parise ER, de Carvalho L. Coffee has hepatoprotective benefits in Brazilian patients with chronic hepatitis C even in lower daily consumption than in American and European populations. Braz J Infect Dis 2014; 18:170-6. [PMID: 24275378 PMCID: PMC9427488 DOI: 10.1016/j.bjid.2013.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 09/15/2013] [Accepted: 09/17/2013] [Indexed: 12/27/2022] Open
Abstract
The potential role of coffee as a hepatoprotective substance for chronic liver diseases has been widely discussed. Our main aim was to evaluate the effect of coffee intake regarding clinical, biochemical tests and liver biopsy data in treatment naïve patients with chronic hepatitis C. One hundred and thirty-six patients with chronic hepatitis C, diagnosed through liver biopsy, or by means of clinical, ultrasound or endoscopic signs of cirrhosis, were assessed by determination of biochemical tests, metabolic and morphological alterations. Food frequency was scrutinized by using a structured questionnaire. Coffee intake represented more than 90% of the total daily caffeine, and the 75th percentile was 4-Brazilian coffee-cup/day (≥255 mL/day or ≥123 mg caffeine/day). According to caffeine intake, patients were divided into two groups (< or ≥123 mg caffeine/day). Patients with higher ingestion of caffeine had lower serum levels of aspartate aminotransferase (× upper limit of normal) (1.8 ± 1.5 vs 2.3 ± 1.5, p = 0.04), lower frequencies of advanced (F3, F4) fibrosis (23.5% vs 54.5%, p < 0.001) and of histological activity grade (A3, A4) observed in liver biopsies (13.8% vs 36.9%, p < 0.001). By multivariate logistic regression, fibrosis was independently associated with caffeine intake (OR– 0.16; 95%CI – 0.03–0.80; p = 0.026), γ-glutamil transferase serum levels and morphological activity. But only fibrosis was associated with histological activity. In conclusion caffeine consumption greater than 123 mg/day was associated with reduced hepatic fibrosis. In addition, this study supports the assumption that coffee intake has hepatoprotective benefits for Brazilian patients with chronic hepatitis C, even in lower doses than that of American and European population intake.
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102
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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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103
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Subramanian M, Kini R, Madasu M, Ohta A, Nowak M, Exley M, Sitkovsky M, Ohta A. Extracellular adenosine controls NKT-cell-dependent hepatitis induction. Eur J Immunol 2014; 44:1119-29. [PMID: 24448964 DOI: 10.1002/eji.201343866] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 12/19/2013] [Accepted: 01/17/2014] [Indexed: 01/18/2023]
Abstract
Extracellular adenosine regulates inflammatory responses via the A2A adenosine receptor (A2AR). A2AR deficiency results in much exaggerated acute hepatitis, indicating nonredundancy of adenosine-A2AR pathway in inhibiting immune activation. To identify a critical target of immunoregulatory effect of extracellular adenosine, we focused on NKT cells, which play an indispensable role in hepatitis. An A2AR agonist abolished NKT-cell-dependent induction of acute hepatitis by concanavalin A (Con A) or α-galactosylceramide in mice, corresponding to downregulation of activation markers and cytokines in NKT cells and of NK-cell co-activation. These results show that A2AR signaling can downregulate NKT-cell activation and suppress NKT-cell-triggered inflammatory responses. Next, we hypothesized that NKT cells might be under physiological control of the adenosine-A2AR pathway. Indeed, both Con A and α-galactosylceramide induced more severe hepatitis in A2AR-deficient mice than in WT controls. Transfer of A2AR-deficient NKT cells into A2AR-expressing recipients resulted in exaggeration of Con A-induced liver damage, suggesting that NKT-cell activation is controlled by endogenous adenosine via A2AR, and this physiological regulatory mechanism of NKT cells is critical in the control of tissue-damaging inflammation. The current study suggests the possibility to manipulate NKT-cell activity in inflammatory disorders through intervention to the adenosine-A2AR pathway.
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Affiliation(s)
- Meenakshi Subramanian
- New England Inflammation and Tissue Protection Institute, Northeastern University, Boston, MA, USA
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104
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Chan ESL, Fernandez P, Cronstein BN. Methotrexate in rheumatoid arthritis. Expert Rev Clin Immunol 2014; 3:27-33. [DOI: 10.1586/1744666x.3.1.27] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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105
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106
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Zhu Y, Men R, Wen M, Hu X, Liu X, Yang L. Blockage of TRPM7 channel induces hepatic stellate cell death through endoplasmic reticulum stress-mediated apoptosis. Life Sci 2014; 94:37-44. [DOI: 10.1016/j.lfs.2013.10.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 09/20/2013] [Accepted: 10/24/2013] [Indexed: 12/20/2022]
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107
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Gordillo-Bastidas D, Oceguera-Contreras E, Salazar-Montes A, González-Cuevas J, Hernández-Ortega LD, Armendáriz-Borunda J. Nrf2 and Snail-1 in the prevention of experimental liver fibrosis by caffeine. World J Gastroenterol 2013; 19:9020-9033. [PMID: 24379627 PMCID: PMC3870555 DOI: 10.3748/wjg.v19.i47.9020] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/19/2013] [Accepted: 08/06/2013] [Indexed: 02/06/2023] Open
Abstract
AIM: To determine the molecular mechanisms involved in experimental hepatic fibrosis prevention by caffeine (CFA).
METHODS: Liver fibrosis was induced in Wistar rats by intraperitoneal thioacetamide or bile duct ligation and they were concomitantly treated with CFA (15 mg/kg per day). Fibrosis and inflammatory cell infiltrate were evaluated and classified by Knodell index. Inflammatory infiltrate was quantified by immunohistochemistry (anti-CD11b). Gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction for collagen I (Col-1), connective tissue growth factor (CTGF), transforming growth factor β1 (TGF-β1), tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-1), IL-6, superoxide dismutase (SOD) and catalase (CAT). Activation of Nrf2 and Snail-1 was analyzed by Western-blot. TNF-α expression was proved by enzyme-linked immunosorbant assay, CAT activity was performed by zymography.
RESULTS: CFA treatment diminished fibrosis index in treated animals. The Knodell index showed both lower fibrosis and necroinflammation. Expression of profibrogenic genes CTGF, Col-1 and TGF-β1 and proinflammatory genes TNF-α, IL-6 and IL-1 was substantially diminished with CFA treatment with less CD11b positive areas. Significantly lower values of transcriptional factor Snail-1 were detected in CFA treated rats compared with cirrhotic rats without treatment; in contrast Nrf2 was increased in the presence of CFA. Expression of SOD and CAT was greater in animals treated with CFA showing a strong correlation between mRNA expression and enzyme activity.
CONCLUSION: Our results suggest that CFA inhibits the transcriptional factor Snail-1, down-regulating profibrogenic genes, and activates Nrf2 inducing antioxidant enzymes system, preventing inflammation and fibrosis.
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108
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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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Perez-Aso M, Fernandez P, Mediero A, Chan ES, Cronstein BN. Adenosine 2A receptor promotes collagen production by human fibroblasts via pathways involving cyclic AMP and AKT but independent of Smad2/3. FASEB J 2013; 28:802-12. [PMID: 24200882 DOI: 10.1096/fj.13-241646] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Activation of adenosine A2A receptor (A2AR) promotes fibrosis and collagen synthesis. However, the underlying mechanism is still unclear, not least because cAMP, its principal effector, has been found to inhibit TGFβ1-induced collagen synthesis. Here, we show that in primary normal human dermal fibroblasts, A2AR stimulation with CGS21680 elicits a modest cAMP increase (150 ± 12% of control; EC50 54.8 nM), which stimulates collagen1 (Col1) and collagen3 (Col3), but maximal cAMP resulting from direct activation of adenylyl cyclase by forskolin (15,689 ± 7038% of control; EC50 360.7 nM) inhibits Col1 and increases Col3. Similar to Col1 expression, fibroblast proliferation increased following physiological cAMP increases by CGS21680 but was inhibited by cAMP increases beyond the physiological range by forskolin. The A2AR-mediated increase of Col1 and Col3 was mediated by AKT, while Col3, but not Col1, expression was dependent on p38 and repressed by ERK. TGFβ1 induced phosphorylation of Smad2/3 and increased Col3 expression, which was prevented by Smad3 depletion. In contrast, CGS21680 did not activate Smad2/3, and Smad2/3 knockdown did not prevent CGS21680-induced Col1 or Col3 increases. Our results indicate that cAMP is a concentration-dependent switch for collagen production via noncanonical, AKT-dependent, Smad2/3-independent signaling. These observations explain the paradoxical effects of cAMP on collagen expression.
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Affiliation(s)
- Miguel Perez-Aso
- 1Department of Medicine, New York University School of Medicine, 550 First Ave., New York, NY 10016, USA.
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110
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Ortiz-Capisano MC, Atchison DK, Harding P, Lasley RD, Beierwaltes WH. Adenosine inhibits renin release from juxtaglomerular cells via an A1 receptor-TRPC-mediated pathway. Am J Physiol Renal Physiol 2013; 305:F1209-19. [PMID: 23884142 DOI: 10.1152/ajprenal.00710.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renin is synthesized and released from juxtaglomerular (JG) cells. Adenosine inhibits renin release via an adenosine A1 receptor (A1R) calcium-mediated pathway. How this occurs is unknown. In cardiomyocytes, adenosine increases intracellular calcium via transient receptor potential canonical (TRPC) channels. We hypothesized that adenosine inhibits renin release via A1R activation, opening TRPC channels. However, higher concentrations of adenosine may stimulate renin release through A2R activation. Using primary cultures of isolated mouse JG cells, immunolabeling demonstrated renin and A1R in JG cells, but not A2R subtypes, although RT-PCR indicated the presence of mRNA of both A2AR and A2BR. Incubating JG cells with increasing concentrations of adenosine decreased renin release. Different concentrations of the adenosine receptor agonist N-ethylcarboxamide adenosine (NECA) did not change renin. Activating A1R with 0.5 μM N6-cyclohexyladenosine (CHA) decreased basal renin release from 0.22 ± 0.05 to 0.14 ± 0.03 μg of angiotensin I generated per milliliter of sample per hour of incubation (AngI/ml/mg prot) (P < 0.03), and higher concentrations also inhibited renin. Reducing extracellular calcium with EGTA increased renin release (0.35 ± 0.08 μg AngI/ml/mg prot; P < 0.01), and blocked renin inhibition by CHA (0.28 ± 0.06 μg AngI/ml/mg prot; P < 0. 005 vs. CHA alone). The intracellular calcium chelator BAPTA-AM increased renin release by 55%, and blocked the inhibitory effect of CHA. Repeating these experiments in JG cells from A1R knockout mice using CHA or NECA demonstrated no effect on renin release. However, RT-PCR showed mRNA from TRPC isoforms 3 and 6 in isolated JG cells. Adding the TRPC blocker SKF-96365 reversed CHA-mediated inhibition of renin release. Thus A1R activation results in a calcium-dependent inhibition of renin release via TRPC-mediated calcium entry, but A2 receptors do not regulate renin release.
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Affiliation(s)
- M Cecilia Ortiz-Capisano
- Henry Ford Hospital, Dept. of Medicine, Hypertension and Vascular Research Division, 7088 E&R Bldg., 2799 W. Grand Blvd., Detroit, MI 48202.
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111
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Adenosine 2A receptor antagonist prevented and reversed liver fibrosis in a mouse model of ethanol-exacerbated liver fibrosis. PLoS One 2013; 8:e69114. [PMID: 23874883 PMCID: PMC3715448 DOI: 10.1371/journal.pone.0069114] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Accepted: 06/06/2013] [Indexed: 12/26/2022] Open
Abstract
UNLABELLED The effect of moderate alcohol consumption on liver fibrosis is not well understood, but evidence suggests that adenosine may play a role in mediating the effects of moderate ethanol on tissue injury. Ethanol increases the concentration of adenosine in the liver. Adenosine 2A receptor (A2AR) activation is known to enhance hepatic stellate cell (HSC) activation and A2AR deficient mice are protected from fibrosis in mice. Making use of a novel mouse model of moderate ethanol consumption in which female C57BL/6J mice were allowed continued access to 2% (vol/vol) ethanol (11% calories) or pair-fed control diets for 2 days, 2 weeks or 5 weeks and superimposed with exposure to CCl4, we tested the hypothesis that moderate ethanol consumption increases fibrosis in response to carbon tetrachloride (CCl4) and that treatment of mice with an A2AR antagonist prevents and/or reverses this ethanol-induced increase in liver fibrosis. Neither the expression or activity of CYP2E1, required for bio-activation of CCl4, nor AST and ALT activity in the plasma were affected by ethanol, indicating that moderate ethanol did not increase the direct hepatotoxicity of CCl4. However, ethanol feeding enhanced HSC activation and exacerbated liver fibrosis upon exposure to CCl4. This was associated with an increased sinusoidal angiogenic response in the liver. Treatment with A2AR antagonist both prevented and reversed the ability of ethanol to exacerbate liver fibrosis. CONCLUSION Moderate ethanol consumption exacerbates hepatic fibrosis upon exposure to CCl4. A2AR antagonism may be a potential pharmaceutical intervention to decrease hepatic fibrosis in response to ethanol.
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112
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Perez-Aso M, Mediero A, Cronstein BN. Adenosine A2A receptor (A2AR) is a fine-tune regulator of the collagen1:collagen3 balance. Purinergic Signal 2013; 9:573-83. [PMID: 23749290 DOI: 10.1007/s11302-013-9368-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/15/2013] [Indexed: 12/12/2022] Open
Abstract
Adenosine is a potent endogenous anti-inflammatory and immunosuppressive metabolite that is a potent modulator of tissue repair. However, the adenosine A2A receptor (A2AR)-mediated promotion of collagen synthesis is detrimental in settings such as scarring and scleroderma. The signaling cascade from A2AR stimulation to increased collagen production is complex and obscure, not least because cAMP and its downstream molecules PKA and Epac1 have been reported to inhibit collagen production. We therefore examined A2AR-stimulated signaling for collagen production by normal human dermal fibroblasts (NHDF). Collagen1 (Col1) and collagen3 (Col3) content after A2AR activation by CGS21680 was studied by western blotting. Contribution of PKA and Epac was analyzed by the PKA inhibitor PKI and by knockdowns of the PKA-Cα, -Cβ, -Cγ, Epac1, and Epac2. CGS21680 stimulates Col1 expression at significantly lower concentrations than those required to stimulate Col3 expression. A2AR stimulates Col1 expression by a PKA-dependent mechanism since PKA inhibition or PKA-Cα and -Cβ knockdown prevents A2AR-mediated Col1 increase. In contrast, A2AR represses Col3 via PKA but stimulates both Col1 and Col3 via an Epac2-dependent mechanism. A2AR stimulation with CGS21680 at 0.1 μM increased Col3 expression only upon PKA blockade. A2AR activation downstream signaling for Col1 and Col3 expression proceeds via two distinct pathways with varying sensitivity to cAMP activation; more highly cAMP-sensitive PKA activation stimulates Col1 expression, and less cAMP-sensitive Epac activation promotes both Col1 and Col3 expression. These observations may explain the dramatic change in Col1:Col3 ratio in hypertrophic and immature scars, where adenosine is present in higher concentrations than in normal skin.
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Affiliation(s)
- Miguel Perez-Aso
- Division of Translational Medicine, Department of Medicine, New York University School of Medicine, 550 First Avenue, MSB 255, New York, NY, 10016, USA,
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113
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Xiao H, Si LY, Liu W, Li N, Meng G, Yang N, Chen X, Zhou YG, Shen HY. The effects of adenosine A2A receptor knockout on renal interstitial fibrosis in a mouse model of unilateral ureteral obstruction. Acta Histochem 2013; 115:315-9. [PMID: 23026406 DOI: 10.1016/j.acthis.2012.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/30/2012] [Accepted: 09/05/2012] [Indexed: 11/15/2022]
Abstract
Adenosine A2A receptor (A2AR) plays an important regulatory role in the processes of inflammation and fibrosis. However, it is unknown whether A2AR can mediate renal interstitial fibrosis (RIF). To evaluate the effect of genetic A2AR knockout (KO) on the pathological progress of RIF, we applied a unilateral ureteral obstruction (UUO) model of RIF on A2AR KO mice and their wild-type (WT) littermates. Renal pathological assessment was performed at different post-UUO stages using hematoxylin and eosin (H&E) and Masson's trichrome staining as well as quantitative morphological analysis. Our data demonstrated that: (i) the extent of RIF was determined by the development of UUO in a time-dependent manner; (ii) A2AR KO exacerbated the pathological progress of RIF in mice at the early post-UUO stage, i.e. day 3 and day 7; (iii) the profibrotic effect of A2AR KO was prominent until the late post-UUO stage, i.e. day 14, at which RIF reached a similar severity level in A2AR KO and WT mice. Our findings revealed that A2AR KO significantly exacerbated the progression of UUO-induced RIF in mice, prominently at the initial stage.
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Affiliation(s)
- Hang Xiao
- Molecular Biology Center, State Key Laboratory of Trauma, Burns, and Combined Injury, Research Institute of Surgery and Daping Hospital, Third Military Medical University, Chongqing 400042, China
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Chen JF, Eltzschig HK, Fredholm BB. Adenosine receptors as drug targets--what are the challenges? Nat Rev Drug Discov 2013; 12:265-86. [PMID: 23535933 PMCID: PMC3930074 DOI: 10.1038/nrd3955] [Citation(s) in RCA: 650] [Impact Index Per Article: 59.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adenosine signalling has long been a target for drug development, with adenosine itself or its derivatives being used clinically since the 1940s. In addition, methylxanthines such as caffeine have profound biological effects as antagonists at adenosine receptors. Moreover, drugs such as dipyridamole and methotrexate act by enhancing the activation of adenosine receptors. There is strong evidence that adenosine has a functional role in many diseases, and several pharmacological compounds specifically targeting individual adenosine receptors--either directly or indirectly--have now entered the clinic. However, only one adenosine receptor-specific agent--the adenosine A2A receptor agonist regadenoson (Lexiscan; Astellas Pharma)--has so far gained approval from the US Food and Drug Administration (FDA). Here, we focus on the biology of adenosine signalling to identify hurdles in the development of additional pharmacological compounds targeting adenosine receptors and discuss strategies to overcome these challenges.
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Affiliation(s)
- Jiang-Fan Chen
- Department of Neurology and Pharmacology, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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115
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Puig L. Methotrexate: new therapeutic approaches. ACTAS DERMO-SIFILIOGRAFICAS 2013; 105:583-9. [PMID: 23434058 DOI: 10.1016/j.ad.2012.11.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 11/15/2022] Open
Abstract
Although the first study on the efficacy of methotrexate in the treatment of psoriasis was reported in 1958, scientific evidence for this indication has been scant until quite recently. We now have new data on the pharmacokinetics and mechanism of action of methotrexate and new subcutaneous formulations that have improved the bioavailability, efficacy, and ease of administration of the drug. The results of recent clinical trials comparing methotrexate with several biologic agents have shown it to be the first-line therapy among the classic systemic treatments for psoriasis. Moreover, the incremental cost-effectiveness ratio for subcutaneous methotrexate has been shown to be superior to that of ciclosporin, adalimumab, and infliximab.
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Affiliation(s)
- L Puig
- Servicio de Dermatología, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, España.
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Padovan M, Vincenzi F, Govoni M, Bortoluzzi A, Borea PA, Varani K. Adenosine and adenosine receptors in rheumatoid arthritis. ACTA ACUST UNITED AC 2013. [DOI: 10.2217/ijr.12.76] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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117
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Karmouty-Quintana H, Xia Y, Blackburn MR. Adenosine signaling during acute and chronic disease states. J Mol Med (Berl) 2013; 91:173-81. [PMID: 23340998 DOI: 10.1007/s00109-013-0997-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 01/04/2013] [Accepted: 01/08/2013] [Indexed: 12/18/2022]
Abstract
Adenosine is a signaling nucleoside that is produced following tissue injury, particularly injury involving ischemia and hypoxia. The production of extracellular adenosine and its subsequent signaling through adenosine receptors plays an important role in orchestrating injury responses in multiple organs. There are four adenosine receptors that are widely distributed on immune, epithelial, endothelial, neuronal,and stromal cells throughout the body. Interestingly, these receptors are subject to altered regulation following injury. Studies in mouse models and human cells and tissues have identified that the production of adenosine and its subsequent signaling through its receptors plays largely beneficial roles in acute disease states, with the exception of brain injury. In contrast, if elevated adenosine levels are sustained beyond the acute injury phase, adenosine responses can become detrimental by activating pathways that promote tissue injury and fibrosis. Understanding when during the course of disease adenosine signaling is beneficial as opposed to detrimental and defining the mechanisms involved will be critical for the advancement of adenosine-based therapies for acute and chronic diseases. The purpose of this review is to discuss key observations that define the beneficial and detrimental aspects of adenosine signaling during acute and chronic disease states with an emphasis on cellular processes, such as inflammatory cell regulation, vascular barrier function, and tissue fibrosis.
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Affiliation(s)
- Harry Karmouty-Quintana
- Department of Biochemistry and Molecular Biology, The University of Texas Medical School at Houston, 6431 Fannin Blvd, Suite 6.200, Houston, TX 77030, USA
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118
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119
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Smith GP, Chan ES. Immunomodulating pharmaceuticals. Clin Immunol 2013. [DOI: 10.1016/b978-0-7234-3691-1.00101-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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120
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Sarobo C, Lacorte LM, Martins M, Rinaldi JC, Moroz A, Scarano WR, Delella FK, Felisbino SL. Chronic caffeine intake increases androgenic stimuli, epithelial cell proliferation and hyperplasia in rat ventral prostate. Int J Exp Pathol 2012; 93:429-37. [PMID: 23136995 PMCID: PMC3521899 DOI: 10.1111/j.1365-2613.2012.00843.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/13/2012] [Indexed: 12/01/2022] Open
Abstract
Coffee intake has been associated with a low risk of developing cancer, including prostate cancer, which is one of the most commonly diagnosed cancer in men. However, few studies have evaluated the chronic effects of caffeine, which is the most abundant methylxanthine in coffee, on prostate morphology and physiology. In the present study, we investigated the effects of chronic, low-dose caffeine intake on rat prostate morphology from puberty to adulthood. Five-week-old male Wistar rats were randomized into two experimental groups: caffeine-treated (20 ppm in drinking water, n = 12) and control (n = 12). The ventral and dorsolateral prostates were dissected, weighted and submitted to morphological, morphometrical and immunohistochemical analysis of cellular proliferation, apoptosis and androgen receptor (AR) tissue expression. The testosterone (T) and dihydrotestosterone (DHT) concentrations were measured in the plasma. Our results show that caffeine intake increased the concentrations of T and DHT, organ weight, epithelial cell proliferation and AR tissue expression in the ventral prostatic lobe. All the ventral prostates from the caffeine-treated animals presented various degrees of epithelial and stromal hyperplasia. Our results suggest that chronic caffeine intake from puberty increases androgenic signalling and cell proliferation in the rat prostate gland and can be related to the development of benign prostatic hyperplasia.
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Affiliation(s)
- Carolina Sarobo
- Department of Morphology, Institute of Biosciences, Univ Estadual Paulista (UNESP), Botucatu, SP, Brazil
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Fausther M, Sheung N, Saiman Y, Bansal MB, Dranoff JA. Activated hepatic stellate cells upregulate transcription of ecto-5'-nucleotidase/CD73 via specific SP1 and SMAD promoter elements. Am J Physiol Gastrointest Liver Physiol 2012; 303:G904-14. [PMID: 22899823 PMCID: PMC3469697 DOI: 10.1152/ajpgi.00015.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 08/13/2012] [Indexed: 01/31/2023]
Abstract
Adenosine is a potent modulator of liver fibrosis and inflammation. Adenosine has been shown to regulate such diverse activities as chemotaxis, contraction, and matrix production in hepatic stellate cells (HSC). Ecto-5'-nucleotidase/CD73 [EC 3.1.3.5] is the rate-limiting enzyme in adenosine production. Cd73-deficient mice are resistant to experimental liver fibrosis and have impaired adenosine generation. However, cell-specific expression and regulation of CD73 within the fibrotic liver have not been defined. In particular, prior evidence demonstrating that liver myofibroblasts, the cells believed to be responsible for matrix formation in the liver, express CD73 is lacking. Thus we tested the hypothesis that HSC and portal fibroblasts (PF), cells that undergo differentiation into liver myofibroblasts, express CD73 in a regulated fashion. We found that CD73 is weakly expressed in quiescent HSC and PF but is markedly upregulated at the transcriptional level in myofibroblastic HSC and PF. We furthermore found that CD73 protein and its functional activity are strongly increased in fibrous septa in rats subjected to experimental fibrosis. To determine the mechanism for the upregulation of Cd73 gene, we cloned the rat Cd73 promoter and then used serial truncation and site-directed mutagenesis to identify key regulatory elements. We identified two consensus SP1 motifs and one SMAD binding site, each of which was necessary for Cd73 gene upregulation. In conclusion, activated HSC upregulate Cd73 gene expression, via specific SP1 and SMAD promoter elements, after myofibroblastic differentiation. The ecto-5'-nucleotidase/CD73 enzyme is a novel cellular marker of activated liver myofibroblasts in vivo and in vitro and thus represents a promising molecular target for antifibrotic therapies in liver diseases.
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Affiliation(s)
- Michel Fausther
- Division of Gastroenterology and Hepatology, Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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Mantell S, Jones R, Trevethick M. Design and application of locally delivered agonists of the adenosine A(2A) receptor. Expert Rev Clin Pharmacol 2012; 3:55-72. [PMID: 22111533 DOI: 10.1586/ecp.09.57] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The broad spectrum anti-inflammatory actions of adenosine A(2A) receptor agonists are well described. The wide distribution of this receptor, however, suggests that the therapeutic potential of these agents is likely to reside in topical treatments to avoid systemic side effects associated with oral administration. Adenosine A(2A) receptor agonists have been assessed as topical agents: GW328267X (GSK; allergic rhinitis and asthma), UK-432097 (Pfizer; chronic obstructive pulmonary disease [COPD]) and Sonedenoson (MRE0094, King Pharmaceuticals; wound healing). All trials failed to achieve effects against the desired clinical end points. This broad-based review will discuss general principles of chemical design of topically applied agents and potential therapeutic topical applications of current adenosine A(2A) receptor agonists. Potential factors contributing to the lack of efficacy in the above clinical trials will be discussed together with design principles, which may influence efficacy in disease states. Our analysis suggests that adenosine A(2A) receptor agonists have a wide therapeutic potential as topical agents in a wide variety of diseases, such as neutrophil-dependent lung diseases (acute lung injury, exacerbations in asthma and COPD), allergic rhinitis, glaucoma and wound repair. Factors that will influence topical activity include formulation, tissue retention, compound potency, receptor kinetics and pharmacokinetics.
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Affiliation(s)
- Simon Mantell
- PC 675, Pfizer Global R&D, Sandwich, Kent, CT13 9NJ, UK.
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Abstract
BACKGROUND AND AIMS Adenine is a uric acid pathway metabolite of no known function, and has recently been identified as a ligand for a rat G protein-coupled receptor. Due to the known role of other uric acid pathway metabolites in HSC biology, we tested the ability of adenine to induce HSC differentiation. METHODS RT-PCR was performed for adenine receptor expression in T-6 and primary rat HSC. T-6 and primary rats HSC were cultured with and without adenine, and stellation examined. Next, we examined inhibition of calcium signaling using caged IP(3). To test if adenine inhibits HSC chemotaxis T-6 cells and rat HSCs were cultured with or without adenine for 24 h in a transwell assay with PDGF as the chemoattractant. cDNA was prepared from T-6 and primary HSC for quantification of collagen 1 mRNA using real-time PCR. RESULTS We found that mRNA for the adenine receptor is expressed in T-6 cells and primary rat HSC. Also, adenine induces HSC stellation and adenine inhibits IP(3) mediated increase in cytosolic [Ca(2+)](i) and inhibits chemotaxis in T-6 cells and primary rat HSC. Adenine was also shown to up-regulate α-SMA and collagen 1, and this effect is lost by using specific si-RNA for the adenine receptor. Finally, adenine inhibits endothelin-1-induced gel contraction. CONCLUSIONS The adenine receptor is present in T-6 cells and primary rats HSC. Adenine, via the adenine receptor, induces morphological change, and cytosolic calcium signaling, inhibits chemotaxis, and up-regulates collagen 1 mRNA in HSCs.
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Furtado KS, Prado MG, Aguiar E Silva MA, Dias MC, Rivelli DP, Rodrigues MAM, Barbisan LF. Coffee and caffeine protect against liver injury induced by thioacetamide in male Wistar rats. Basic Clin Pharmacol Toxicol 2012; 111:339-47. [PMID: 22646289 DOI: 10.1111/j.1742-7843.2012.00903.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 05/07/2012] [Indexed: 11/29/2022]
Abstract
Coffee intake has been inversely related to the incidence of liver diseases, although there are controversies on whether these beneficial effects on human health are because of caffeine or other specific components in this popular beverage. Thus, this study evaluated the protective effects of coffee or caffeine intake on liver injury induced by repeated thioacetamide (TAA) administration in male Wistar rats. Rats were randomized into five groups: one untreated group (G1) and four groups (G2-G5) treated with the hepatotoxicant TAA (200 mg/kg b.w., i.p.) twice a week for 8 weeks. Concomitantly, rats received tap water (G1 and G2), conventional coffee (G3), decaffeinated coffee (G4) or 0.1% caffeine (G5). After 8 weeks of treatment, rats were killed and blood and liver samples were collected. Conventional and decaffeinated coffee and caffeine intake significantly reduced serum levels of alanine aminotransferase (ALT) (p < 0.001) and oxidized glutathione (p < 0.05), fibrosis/inflammation scores (p < 0.001), collagen volume fraction (p < 0.01) and transforming growth factor β-1 (TGF-β1) protein expression (p ≤ 0.001) in the liver from TAA-treated groups. In addition, conventional coffee and caffeine intake significantly reduced proliferating cellular nuclear antigen (PCNA) S-phase indexes (p < 0.001), but only conventional coffee reduced cleaved caspase-3 indexes (p < 0.001), active metalloproteinase 2 (p ≤ 0.004) and the number of glutathione S-transferase placental form (GST-P)-positive preneoplastic lesions (p < 0.05) in the liver from TAA-treated groups. In conclusion, conventional coffee and 0.1% caffeine intake presented better beneficial effects than decaffeinated coffee against liver injury induced by TAA in male Wistar rats.
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Affiliation(s)
- Kelly S Furtado
- Department of Pathology, School of Medicine, Sao Paulo State University-UNESP, Botucatu, Sao Paulo, Brazil
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Panchal SK, Wong WY, Kauter K, Ward LC, Brown L. Caffeine attenuates metabolic syndrome in diet-induced obese rats. Nutrition 2012; 28:1055-62. [PMID: 22721876 DOI: 10.1016/j.nut.2012.02.013] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 02/25/2012] [Accepted: 02/25/2012] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Caffeine is a constituent of many non-alcoholic beverages. Pharmacological actions of caffeine include the antagonism of adenosine receptors and the inhibition of phosphodiesterase activity. The A₁ adenosine receptors present on adipocytes are involved in the control of fatty acid uptake and lipolysis. In this study, the effects of caffeine were characterized in a diet-induced metabolic syndrome in rats. METHODS Rats were given a high-carbohydrate, high-fat diet (mainly containing fructose and beef tallow) for 16 wk. The control rats were given a corn starch diet. Treatment groups were given caffeine 0.5 g/kg of food for the last 8 wk of the 16-wk protocol. The structure and function of the heart and the liver were investigated in addition to the metabolic parameters including the plasma lipid components. RESULTS The high-carbohydrate, high-fat diet induced symptoms of metabolic syndrome, including obesity, dyslipidemia, impaired glucose tolerance, decreased insulin sensitivity, and increased systolic blood pressure, associated with the development of cardiovascular remodeling and non-alcoholic steatohepatitis. The treatment with caffeine in the rats fed the high-carbohydrate, high-fat diet decreased body fat and systolic blood pressure, improved glucose tolerance and insulin sensitivity, and attenuated cardiovascular and hepatic abnormalities, although the plasma lipid concentrations were further increased. CONCLUSION Decreased total body fat, concurrent with increased plasma lipid concentrations, reflects the lipolytic effects of caffeine in adipocytes, likely owing to the caffeine antagonism of A₁ adenosine receptors on adipocytes.
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Affiliation(s)
- Sunil K Panchal
- Department of Biological and Physical Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia
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Guillén-Gómez E, Pinilla-Macua I, Pérez-Torras S, Choi DS, Arce Y, Ballarín JA, Pastor-Anglada M, Díaz-Encarnación MM. New role of the human equilibrative nucleoside transporter 1 (hENT1) in epithelial-to-mesenchymal transition in renal tubular cells. J Cell Physiol 2012; 227:1521-8. [PMID: 21678404 DOI: 10.1002/jcp.22869] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Epithelial-to-mesenchymal transition (EMT) is an important pro-fibrotic event in which tubular epithelial cells are transformed into myofibroblasts. Nucleoside transporters (NT) are regulated by many factors and processes, some of which are involved in fibrosis, such as cytokines, inflammation, and proliferation. Equilibrative nucleoside transporter 1 (ENT1) has been proved to be the most widely expressed adenosine transporter. In that sense, ENT1 may be a key player in cell damage signaling. Here we analyze the role of human ENT1 (hENT1) in the EMT process in proximal tubular cells. Addition of the main inducer of EMT, the transforming growth factor-β1, to HK-2 cells increased hENT1 mRNA and protein level expression. ENT1-mediated adenosine uptake was also enhanced. When cells were incubated with dipyridamole to evaluate the potential contribution of ENT1 to EMT by blocking its transport activity, EMT was induced. Moreover, the knock down of hENT1 with siRNA induced EMT and collagen production in HK-2 cells. Kidneys isolated from ENT1 knockout mice showed higher levels of interstitial collagen and α-SMA positive cells than wild-type mice. Our results point to a new potential role of hENT1 as a modulator of EMT in proximal tubular cells. In this sense, hENT1 could be involved in renal protection processes, and the loss or reduced expression of hENT1 would lead to an increased vulnerability of cells to the onset and/or progression of renal fibrosis.
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Affiliation(s)
- Elena Guillén-Gómez
- Laboratori de Biologia Molecular, Universitat Autònoma de Barcelona, Fundació Puigvert, REDinREN, Institut Investigació Biosanitaria Sant Pau, Barcelona, Catalonia, Spain.
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Recovery of the Cell Cycle Inhibition in CCl(4)-Induced Cirrhosis by the Adenosine Derivative IFC-305. Int J Hepatol 2012; 2012:212530. [PMID: 23056951 PMCID: PMC3463961 DOI: 10.1155/2012/212530] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 08/01/2012] [Accepted: 08/21/2012] [Indexed: 12/16/2022] Open
Abstract
Introduction. Cirrhosis is a chronic degenerative illness characterized by changes in normal liver architecture, failure of hepatic function, and impairment of proliferative activity. The aim of this study is to know how IFC-305 compound induces proliferation of the liver during reversion of cirrhosis. Methods. Once cirrhosis has been installed by CCl(4) treatment for 10 weeks in male Wistar rats, they were divided into four groups: two received saline and two received the compound; all were euthanized at 5 and 10 weeks of treatment. Liver homogenate, mitochondria, and nucleus were used to measure cyclins, CDKs, and cell cycle regulatory proteins PCNA, pRb, p53, E2F, p21, p27, HGF, liver ATP, and mitochondrial function. Results. Diminution and small changes were observed in the studied proteins in the cirrhotic animals without treatment. The IFC-305-treated rats showed a clear increase in most of the proteins studied mainly in PCNA and CDK6, and a marked increased in ATP and mitochondrial function. Discussion/Conclusion. IFC-305 induces a recovery of the cell cycle inhibition promoting recovery of DNA damage through the action of PCNA and p53. The increase in energy and preservation of mitochondrial function contribute to recovering the proliferative function.
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Cohen-Naftaly M, Friedman SL. Current status of novel antifibrotic therapies in patients with chronic liver disease. Therap Adv Gastroenterol 2011; 4:391-417. [PMID: 22043231 PMCID: PMC3187682 DOI: 10.1177/1756283x11413002] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Fibrosis accumulation is a dynamic process resulting from a wound-healing response to acute or chronic liver injury of all causes. The cascade starts with hepatocyte necrosis and apoptosis, which instigate inflammatory signaling by chemokines and cytokines, recruitment of immune cell populations, and activation of fibrogenic cells, culminating in the deposition of extracellular matrix. These key elements, along with pathways of transcriptional and epigenetic regulation, represent fertile therapeutic targets. New therapies include drugs specifically designed as antifibrotics, as well as drugs already available with well-established safety profiles, whose mechanism of action may also be antifibrotic. At the same time, the development of noninvasive fibrogenic markers, and techniques (e.g. fibroscan), as well as combined scoring systems incorporating serum and clinical features will allow improved assessment of therapy response. In aggregate, the advances in the elucidation of the biology of fibrosis, combined with improved technologies for assessment will provide a comprehensive framework for design of antifibrotics and their analysis in well-designed clinical trials. These efforts may ultimately yield success in halting the progression of, or reversing, liver fibrosis.
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Affiliation(s)
| | - Scott L. Friedman
- Fishberg Professor of Medicine, Division of Liver Diseases, Box 1123, Mount Sinai School of Medicine, 1425 Madison Avenue, Room 11-70C, New York, NY 10029-6574, USA
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A novel fused 1,2,4-triazine aryl derivative as antioxidant and nonselective antagonist of adenosine A(2A) receptors in ethanol-activated liver stellate cells. Chem Biol Interact 2011; 195:18-24. [PMID: 22063920 DOI: 10.1016/j.cbi.2011.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 09/23/2011] [Accepted: 10/19/2011] [Indexed: 01/01/2023]
Abstract
It has been detected that hepatic adenosine A(2A) receptors play an active role in the pathogenesis of hepatic fibrosis and suggest a novel therapeutic target in the treatment and prevention of hepatic cirrhosis. In this paper we examined if our new triazine derivative (IMT) can inhibit ethanol-induced activation of HSCs measured as increased α-SMA, collagen synthesis and enhanced oxidative stress in rat liver stellate cells. We also investigated its influence on cytokines (TGF-β, TNF-α) synthesis, MMP-2 and TIMP-1 production and ethanol-induced intracellular signal transduction. Moreover, with using of known adenosine A(2A) receptor agonist (CGS 21680), and antagonist (SCH 58261) we examined if this triazine derivative acts on adenosine receptors. We detected a strong antagonistic action of new triazine derivative (IMT) on ethanol-induced rat liver stellate cells activation, observed as a significant decrease in α-SMA, collagen synthesis, reactive oxygen species production, TGF-β, TNF-α, MMP-2 and TIMP-1 production as well as JNK, p38MAPK, NFκB, IκB, Smad3 phosphorylation. Moreover, IMT strongly inhibited activation of stellate cells by known selective agonist of adenosine A(2A) receptor (CGS 21680). When known A(2A) receptor antagonist (SCH 58261) was used together with IMT this effect was not spectacular. Additionally, only slight enhancement of inhibition was observed when cells were pretreated both IMT with SCH 58261, hence we suppose that IMT acts as nonselective antagonist of A(2A) receptors, and, besides its antioxidant activity, also by this way inhibited ethanol-induced stellate cell activation.
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Lazzerini PE, Natale M, Gianchecchi E, Capecchi PL, Montilli C, Zimbone S, Castrichini M, Balistreri E, Ricci G, Selvi E, Garcia-Gonzalez E, Galeazzi M, Laghi-Pasini F. Adenosine A2A receptor activation stimulates collagen production in sclerodermic dermal fibroblasts either directly and through a cross-talk with the cannabinoid system. J Mol Med (Berl) 2011; 90:331-42. [PMID: 22033526 DOI: 10.1007/s00109-011-0824-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 09/30/2011] [Accepted: 10/10/2011] [Indexed: 01/16/2023]
Abstract
Systemic sclerosis (SSc) is a connective tissue disease characterised by exaggerated collagen deposition in the skin and visceral organs. Adenosine A2A receptor stimulation (A2Ar) promotes dermal fibrosis, while the cannabinoid system modulates fibrogenesis in vitro and in animal models of SSc. Moreover, evidence in central nervous system suggests that A2A and cannabinoid (CB1) receptors may physically and functionally interact. On this basis, we investigated A2Ar expression and function in modulating collagen biosynthesis from SSc dermal fibroblasts and analysed the cross-talk with cannabinoid receptors. In sclerodermic cells, A2Ar expression (RT-PCR, Western blotting) was evaluated together with the effects of A2A agonists and/or antagonists on collagen biosynthesis (EIA, Western blotting). Putative physical and functional interactions between the A2A and cannabinoid receptors were respectively assessed by co-immuno-precipitation and co-incubating the cells with the unselective cannabinoid agonist WIN55,212-2, and the selective A2A antagonist ZM-241385. In SSc fibroblasts, (1) the A2Ar is overexpressed and its occupancy with the selective agonist CGS-21680 increases collagen production, myofibroblast trans-differentiation, and ERK-1/2 phosphorylation; (2) the A2Ar forms an heteromer with the cannabinoid CB1 receptor; and (3) unselective cannabinoid receptor stimulation with a per se ineffective dose of WIN55,212-2, results in a marked anti-fibrotic effect after A2Ar blockage. In conclusion, A2Ar stimulation induces a pro-fibrotic phenotype in SSc dermal fibroblasts, either directly, and indirectly, by activating the CB1 cannabinoid receptor. These findings increase our knowledge of the pathophysiology of sclerodermic fibrosis also further suggesting a new therapeutic approach to the disease.
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Affiliation(s)
- Pietro Enea Lazzerini
- Department of Clinical Medicine and Immunological Sciences, Division of Clinical Immunology, University of Siena, Siena, Italy
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Zhu X, Shiba H, Fung JJ, Wang LF, Arakawa Y, Irefin S, Demetris AJ, Kelly DM. The role of the A2a receptor agonist, regadenoson, in modulating hepatic artery flow in the porcine small-for-size liver graft. J Surg Res 2011; 174:e37-45. [PMID: 22225980 DOI: 10.1016/j.jss.2011.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 08/22/2011] [Accepted: 10/06/2011] [Indexed: 12/18/2022]
Abstract
BACKGROUND Hepatic artery vasoconstriction plays a major role in the pathophysiology of the small-for-size (SFS) liver graft injury and is reversed by adenosine. The A2a adenosine receptor (AR) has been suggested to be one of the key receptors that modulate hepatic hemodynamic changes. The aim of the study is to define the effects of the A2a AR agonist, regadenoson, in modulating hepatic artery flow (HAF) in SFS liver grafts of a porcine model. METHODS Seven female recipient pigs (66-70 kg) receiving 20% liver grafts were treated with regadenoson, 0.1 ug/kg/min starting on POD1 (n = 7). Results were compared with those with untreated 20% liver grafts (n= 8). The recipients were observed for 14 d. Hepatic artery flow (HAF) and portal vein flow (PVF) were recorded. Liver biopsies and serum samples were also taken at the designed time points through postoperative day (POD)14. RESULTS Dose-response curves of regadenoson established 0.1 ug/kg/min as the most effective dose of regadenoson for maintaining an increase in HAF. No adverse effects were seen with regadenoson infusion. HAF immediately increased by up to 2.2-fold after regadenoson infusion. The levels of daily average of HAF and percentage of HAF in total liver blood flow were 34.5% and 41.8%, respectively, higher in the regadenoson group than in the untreated group. Histologic scores of hepatic artery spasm and bile duct necrosis were significantly lower in the regadenoson group than in the untreated group (P = 0.01 and 0.04, respectively). The complication rates of hepatic artery thrombosis and gastrointestinal bleeding were lower in the regadenoson group than in the untreated group (0/7, 0% versus 2/8, 25% and 0/7, 0% versus 2/8 and 25%, respectively). The 14-d survival rates were 4/7 (57.1 %) in regadenoson group compared with 2/8 (25%) in the untreated group. CONCLUSION Adenosine A2a AR agonist, regadenoson, increases HAF in the recipients of SFS grafts with modest improvements in outcome.
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Affiliation(s)
- Xiaocheng Zhu
- Department of General Surgery, Cleveland Clinic, Cleveland, OH 44195, USA.
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Antilipogenic and anti-inflammatory activities of Codonopsis lanceolata in mice hepatic tissues after chronic ethanol feeding. J Biomed Biotechnol 2011; 2012:141395. [PMID: 22013387 PMCID: PMC3195523 DOI: 10.1155/2012/141395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 08/08/2011] [Indexed: 12/31/2022] Open
Abstract
This study evaluated the antilipogenic and anti-inflammatory effects of Codonopsis lanceolata (C. lanceolata) root extract in mice with alcohol-induced fatty liver and elucidated its underlying molecular mechanisms. Ethanol was introduced into the liquid diet by mixing it with distilled water at 5% (wt/v), providing 36% of the energy, for nine weeks. Among the three different fractions prepared from the C. lanceolata root, the C. lanceolata methanol extract (CME) exhibited the most remarkable attenuation of alcohol-induced fatty liver with respect to various parameters such as hepatic free fatty acid concentration, body weight loss, and hepatic accumulations of triglyceride and cholesterol. The hepatic gene and protein expression levels were analysed via RT-PCR and Western blotting, respectively. CME feeding significantly restored the ethanol-induced downregulation of the adiponectin receptor (adipoR) 1 and of adipoR2, along with their downstream molecules. Furthermore, the study data showed that CME feeding dramatically reversed ethanol-induced hepatic upregulation of toll-like receptor- (TLR-) mediated signaling cascade molecules. These results indicate that the beneficial effects of CME against alcoholic fatty livers of mice appear to be with adenosine- and adiponectin-mediated regulation of hepatic steatosis and TLR-mediated modulation of hepatic proinflammatory responses.
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Cronstein BN. Adenosine receptors and fibrosis: a translational review. F1000 BIOLOGY REPORTS 2011; 3:21. [PMID: 22003368 PMCID: PMC3186039 DOI: 10.3410/b3-21] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Adenosine—a purine nucleoside generated extracellularly from adenine nucleotides released by cells as a result of direct stimulation, hypoxia, trauma, or metabolic stress—is a well-known physiologic and pharmacologic agent. Recent studies demonstrate that adenosine, acting at its receptors, promotes wound healing by stimulating both angiogenesis and matrix production. Subsequently, adenosine and its receptors have also been found to promote fibrosis (excess matrix production) in the skin, lungs, and liver, but to diminish cardiac fibrosis. A commonly ingested adenosine receptor antagonist, caffeine, blocks the development of hepatic fibrosis, an effect that likely explains the epidemiologic finding that coffee drinking, in a dose-dependent fashion, reduces the likelihood of death from liver disease. Accordingly, adenosine may be a good target for therapies that prevent fibrosis of the lungs, liver, and skin.
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Affiliation(s)
- Bruce N Cronstein
- Department of Medicine, Division of Translational Medicine, NYU School of Medicine 550 First Avenue, New York, NY 10016 USA
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Gessi S, Merighi S, Varani K, Borea PA. Adenosine receptors in health and disease. ADVANCES IN PHARMACOLOGY 2011; 61:41-75. [PMID: 21586355 DOI: 10.1016/b978-0-12-385526-8.00002-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The adenosine receptors A(1), A(2A), A(2B), and A(3) are important and ubiquitous mediators of cellular signaling, which play vital roles in protecting tissues and organs from damage. In particular, adenosine triggers tissue protection and repair by different receptor-mediated mechanisms, including an increase of oxygen supply/demand ratio, preconditioning, anti-inflammatory effects, and stimulation of angiogenesis. Considerable advances have been recently achieved in the pharmacological and molecular characterization of adenosine receptors, which have been proposed as targets for drug design and discovery. At the present time, it can be speculated that adenosine A(1), A(2A), A(2B), and A(3) receptor-selective ligands may show utility in the treatment of pain, ischemic conditions, glaucoma, asthma, arthritis, cancer, and other disorders in which inflammation is a feature. This chapter documents the present state of knowledge of adenosine receptors' role in health and disease.
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Affiliation(s)
- Stefania Gessi
- Department of Clinical and Experimental Medicine, Pharmacology Section, University of Ferrara, Italy
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Abstract
Obesity is a global epidemic with more than 1 billion overweight adults and at least 300 million obese patients worldwide. Diabetes is characterized by a defect in insulin secretion or a decrease in sensitivity to insulin, which results in elevated fasting blood glucose. Both obesity and elevated fasting glucose are risk factors for nonalcoholic fatty liver disease, a disease spectrum that includes hepatic steatosis (nonalcoholic fatty liver), nonalcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. Increased adiposity and insulin resistance contribute to the progression from NASH to fibrosis through the development of a profibrotic mileau in the liver, including increased hepatocellular death, increased reactive oxygen species generation, and an altered adipokine/cytokine balance. This review will summarize recent advances in our understanding of the pathological interactions among excessive fat accumulation, insulin resistance, and hepatic fibrogenesis and discuss specific molecular pathways that may be of interest in the development of therapeutic interventions to prevent and/or reverse hepatic fibrosis.
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Affiliation(s)
- Dian J Chiang
- Dept. of Gastroenterology and Hepatology, Cleveland Clinic, OH 44195, USA.
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Andrade CMB, Lopez PLC, Noronha BT, Wink MR, Borojevic R, Margis R, Lenz G, Battastini AMO, Guma FCR. Ecto-5'-nucleotidase/CD73 knockdown increases cell migration and mRNA level of collagen I in a hepatic stellate cell line. Cell Tissue Res 2011; 344:279-86. [PMID: 21424267 DOI: 10.1007/s00441-011-1140-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 01/26/2011] [Indexed: 01/10/2023]
Abstract
Ecto-5'-nucleotidase (eNT/CD73, E.C.3.1.3.5) is a glycosyl phosphatidylinositol (GPI)-linked cell-surface protein with several functions, including the local generation of adenosine from AMP, with the consequent activation of adenosine receptors and the salvaging of extracellular nucleotides. It also apparently functions independently of this activity, e.g., in the mediation of cell-cell adhesion. Liver fibrosis can be considered as a dynamic and integrated cellular response to chronic liver injury and the activation of hepatic stellate cells (HSCs) plays a role in the fibrogenic process. eNT/CD73 and adenosine are reported to play an important role in hepatic fibrosis in murine models. Knockdown of eNT/CD73 leads to an increase in mRNA expression of tissue non-specific alkaline phosphatase (TNALP), another AMP-degrading enzyme and thus no alteration is seen in the total ecto-AMPase activity of the cell. eNT/CD73 knockdown also leads to changes in the expression of collagen I and a clear alteration of cell migration. We suggest that eNT/CD73 protein expression controls cell migration and collagen expression in a mechanism independent of changes in nucleotide metabolism.
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Affiliation(s)
- Cláudia M B Andrade
- Departamento de Bioquímica, UFRGS, Rua Ramiro Barcelos, Porto Alegre, RS, Brazil
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Hocher B, Heiden S, von Websky K, Arafat AM, Rahnenführer J, Alter M, Kalk P, Ziegler D, Fischer Y, Pfab T. Renal effects of the novel selective adenosine A1 receptor blocker SLV329 in experimental liver cirrhosis in rats. PLoS One 2011; 6:e17891. [PMID: 21423778 PMCID: PMC3053401 DOI: 10.1371/journal.pone.0017891] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 02/14/2011] [Indexed: 01/15/2023] Open
Abstract
Liver cirrhosis is often complicated by an impaired renal excretion of water and sodium. Diuretics tend to further deteriorate renal function. It is unknown whether chronic selective adenosine A(1) receptor blockade, via inhibition of the hepatorenal reflex and the tubuloglomerular feedback, might exert diuretic and natriuretic effects without a reduction of the glomerular filtration rate. In healthy animals intravenous treatment with the novel A(1) receptor antagonist SLV329 resulted in a strong dose-dependent diuretic (up to 3.4-fold) and natriuretic (up to 13.5-fold) effect without affecting creatinine clearance. Male Wistar rats with thioacetamide-induced liver cirrhosis received SLV329, vehicle or furosemide for 12 weeks. The creatinine clearance of cirrhotic animals decreased significantly (-36.5%, p<0.05), especially in those receiving furosemide (-41.9%, p<0.01). SLV329 was able to prevent this decline of creatinine clearance. Mortality was significantly lower in cirrhotic animals treated with SLV329 in comparison to animals treated with furosemide (17% vs. 54%, p<0.05). SLV329 did not relevantly influence the degree of liver fibrosis, kidney histology or expression of hepatic or renal adenosine receptors. In conclusion, chronic treatment with SLV329 prevented the decrease of creatinine clearance in a rat model of liver cirrhosis. Further studies will have to establish whether adenosine A(1) receptor antagonists are clinically beneficial at different stages of liver cirrhosis.
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Affiliation(s)
- Berthold Hocher
- Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Susi Heiden
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Karoline von Websky
- Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Ayman M. Arafat
- Department of Endocrinology, Diabetes and Nutrition, Charité Campus Benjamin Franklin, Berlin, Germany
- Department of Clinical Nutrition, German Institute of Human Nutrition, Potsdam-Rehbruecke, Nuthetal, Germany
| | - Jan Rahnenführer
- Institute of Nutritional Science, University of Potsdam, Potsdam, Germany
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
| | - Markus Alter
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Department of Nephrology, Charité Campus Benjamin Franklin, Berlin, Germany
| | - Philipp Kalk
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Department of Nephrology, Charité Campus Benjamin Franklin, Berlin, Germany
| | | | | | - Thiemo Pfab
- Center for Cardiovascular Research/Institute of Pharmacology, Charité, Berlin, Germany
- Department of Nephrology, Charité Campus Benjamin Franklin, Berlin, Germany
- * E-mail:
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Collins SL, Black KE, Chan-Li Y, Ahn YH, Cole PA, Powell JD, Horton MR. Hyaluronan fragments promote inflammation by down-regulating the anti-inflammatory A2a receptor. Am J Respir Cell Mol Biol 2011; 45:675-83. [PMID: 21257926 DOI: 10.1165/rcmb.2010-0387oc] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The tissue microenvironment plays a critical role in regulating inflammation. Chronic inflammation leads to an influx of inflammatory cells and mediators, extracellular matrix turnover, and increased extracellular adenosine. Low molecular weight (LMW) fragments of hyaluronan (HA), a matrix component, play a critical role in lung inflammation and fibrosis by inducing inflammatory gene expression at the injury site. Adenosine, a crucial negative regulator of inflammation, protects tissues from immune destruction via the adenosine A2a receptor (A2aR). Therefore, these two extracellular products of inflammation play opposing roles in regulating immune responses. As such, we wanted to determine the effect of LMW HA on A2aR function. In this article, we demonstrate that LMW HA causes a rapid, significant, and sustained down-regulation of the A2aR. CD44 was found to be necessary for LMW HA to down-modulate the A2aR as was protein kinase C signaling. We also demonstrate that LMW HA induces A2aR down-regulation during inflammation in vivo, and that this down-regulation can be blocked by treatment with an HA-blocking peptide. Because adenosine plays a critical role in limiting inflammation, our data provide a novel mechanism whereby LMW HA itself may further augment inflammation. By defining the pro- and anti-inflammatory properties of extracellular matrix components, we will be better able to identify specific pharmacologic targets as potential therapies.
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Affiliation(s)
- Samuel L Collins
- Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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140
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Abstract
Methylxanthines are an integral part of everyday food and drink consumption even though the majority of humans do not identify them by their chemical name. The breakthrough in understanding the action(s) of methylxanthines was in large part due to the understanding that methylxanthines can function as antagonists of adenosine receptors. This represented an example of scientific search and was instructive in view of both new therapeutic options and alarming realizations. It was the subsequent demonstration of the in vivo critical role of A2A adenosine receptors in controlling excessive collateral inflammatory damage that attracted the attention of immunologists to the A2A-adenosine-receptor-antagonizing methylxanthines. We summarize here data showing that caffeine is capable of preventing the inhibition of antitumor T cells in a hypoxic tumor microenvironment. On the other hand, caffeine may exacerbate liver damage by weakening the tissue-protecting A2A adenosine receptor signaling during episodes of acute liver inflammation. However, methylxanthines may also prevent the excessive hepatic connective tissue deposition that is associated with the progression of chronic hepatitis to cirrhosis, which is one of the common causes of mortality.
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Abstract
Fibrosis is a common feature of chronic liver injury and is initiated by cell death inside the liver. Hepatocyte death results in apoptotic bodies and other cellular debris, which are phagocytosed by hepatic stellate cells (HSCs), resulting in their activation, proliferation, differentiation, and matrix deposition. This profibrotic effect of cellular death is balanced by an antifibrotic effect of HSC death. Many HSC survival signals are obtained from the extracellular matrix, and active proapoptotic signals are provided by immune cells, particularly natural killer (NK) cells. Quiescent HSCs are relatively resistant to apoptotic signals but become sensitive after activation. The important role of NK cells in inducing HSC apoptosis may explain the increased fibrosis associated with immune suppression (e.g., in the transplant recipient) and HIV infection. HSCs also undergo senescence, which limits their function and sensitizes them to apoptosis.
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Affiliation(s)
- Wajahat Mehal
- Section of Digestive Diseases, Yale University, New Haven, Connecticut
| | - Avlin Imaeda
- Section of Digestive Diseases, Yale University, New Haven, Connecticut
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Abstract
Continued elucidation of the mechanisms of hepatic fibrosis has yielded a comprehensive and nuanced portrait of fibrosis progression and regression. The paradigm of hepatic stellate cell (HSC) activation remains the foundation for defining events in hepatic fibrosis and has been complemented by progress in a number of new areas. Cellular sources of extracellular matrix beyond HSCs have been identified. In addition, the role of chemokine, adipokine, neuroendocrine, angiogenic and NAPDH oxidase signaling in the pathogenesis of hepatic fibrosis has been uncovered, as has the contribution of extracellular matrix stiffness to fibrogenesis. There is also increased awareness of the contribution of innate immunity and greater understanding of the complexity of gene regulation in HSCs and myofibroblasts. Finally, both apoptosis and senescence have been recognized as orchestrated programs that eliminate fibrogenic cells during resolution of liver fibrosis. Ironically, the progress that has been made has highlighted the growing disparity between advances in the experimental setting and their translation into new diagnostic tools and treatments. As a result, focus is shifting towards overcoming key translational challenges in order to accelerate the development of new therapies for patients with chronic liver disease.
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Abstract
Increased caffeine consumption is associated with reduced hepatic fibrosis. Apurva A. Modi, Jordan J. Feld, Yoon Park,David E. Kleiner, James E. Everhart, T. Jake Liang, Jay H. Hoofnagle. Hepatology, 2010 Jan;51(1):201-9.
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Affiliation(s)
- Bruce N. Cronstein
- Corresponding author: Paul R. Esserman Professor of Medicine, NYU School of Medicine, 550 First Ave., NBV16N1, New York, NY 10016, TEL 212-263-6404, FAX 212-263-1048,
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Abstract
Methotrexate remains a cornerstone in the treatment of rheumatoid arthritis and other rheumatic diseases. Folate antagonism is known to contribute to the antiproliferative effects that are important in the action of methotrexate against malignant diseases, but concomitant administration of folic or folinic acid does not diminish the anti-inflammatory potential of this agent, which suggests that other mechanisms of action might be operative. Although no single mechanism is sufficient to account for all the anti-inflammatory activities of methotrexate, the release of adenosine from cells has been demonstrated both in vitro and in vivo. Methotrexate might also confer anti-inflammatory properties through the inhibition of polyamines. The biological effects on inflammation associated with adenosine release have provided insight into how methotrexate exerts its effects against inflammatory diseases and at the same time causes some of its well-known adverse effects. These activities contribute to the complex and multifaceted mechanisms that make methotrexate efficacious in the treatment of inflammatory disorders.
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145
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Zhou X, Huang Q, An J, Lu R, Qin X, Jiang L, Li Y, Wang J, Chen J, Qu J. Genetic deletion of the adenosine A2A receptor confers postnatal development of relative myopia in mice. Invest Ophthalmol Vis Sci 2010; 51:4362-70. [PMID: 20484596 DOI: 10.1167/iovs.09-3998] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To critically evaluate whether the adenosine A2A receptor (A2AR) plays a role in postnatal refractive development in mice. METHODS Custom-built biometric systems specifically designed for mice were used to assess the development of relative myopia by examining refraction and biometrics in A2AR knockout (KO) mice and wild-type (WT) littermates between postnatal days (P)28 and P56. Ocular dimensions were measured by customized optical coherence tomography (OCT), refractive state by eccentric infrared photorefraction (EIR), and corneal radius of curvature by modified keratometry. Scleral collagen diameter and density were examined by electron microscopy on P35. The effect of A2AR activation on collagen mRNA expression and on soluble collagen production was examined in cultured human scleral fibroblasts by real-time RT-PCR and a collagen assay kit. RESULTS Compared with WT littermates, the A2AR KO mice displayed relative myopia (average difference, 5.1 D between P28 and P35) and associated increases in VC depth and axial length from P28 to P56. Furthermore, the myopic shift in A2AR KO mice was associated with ultrastructural changes in the sclera: Electron microscopy revealed denser collagen fibrils with reduced diameter in A2AR KO compared with WT. Last, A2AR activation induced expression of mRNAs for collagens I, III, and V and increased production of soluble collagen in cultured human scleral fibroblasts. CONCLUSIONS Genetic deletion of the A2AR promotes development of relative myopia with increased axial length and altered scleral collagen fiber structure during postnatal development in mice. Thus, the A2AR may be important in normal refractive development.
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Affiliation(s)
- Xiangtian Zhou
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, Wenzhou, China
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Kara FM, Doty SB, Boskey A, Goldring S, Zaidi M, Fredholm BB, Cronstein BN. Adenosine A(1) receptors regulate bone resorption in mice: adenosine A(1) receptor blockade or deletion increases bone density and prevents ovariectomy-induced bone loss in adenosine A(1) receptor-knockout mice. ACTA ACUST UNITED AC 2010; 62:534-41. [PMID: 20112380 DOI: 10.1002/art.27219] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Accelerated osteoclastic bone resorption plays a central role in the pathogenesis of osteoporosis and other bone diseases. Because identifying the molecular pathways that regulate osteoclast activity provides a key to understanding the causes of these diseases and developing new treatments, we studied the effect of adenosine A(1) receptor blockade or deletion on bone density. METHODS The bone mineral density (BMD) in adenosine A(1) receptor-knockout (A(1)R-knockout) mice was analyzed by dual x-ray absorptiometry (DXA) scanning, and the trabecular and cortical bone volume was determined by microfocal computed tomography (micro-CT). The mice were ovariectomized or sham-operated, and 5 weeks after surgery, when osteopenia had developed, several parameters were analyzed by DXA scanning and micro-CT. A histologic examination of bones obtained from A(1)R-knockout and wild-type mice was carried out. Visualization of osteoblast function (bone formation) after tetracycline double-labeling was performed by fluorescence microscopy. RESULTS Micro-CT analysis of bones from A(1)R-knockout mice showed significantly increased bone volume. Electron microscopy of bones from A(1)R-knockout mice showed the absence of ruffled borders of osteoclasts and osteoclast bone resorption. Immunohistologic analysis demonstrated that although osteoclasts were present in the A(1)R-knockout mice, they were smaller and often not associated with bone. No morphologic changes in osteoblasts were observed, and bone-labeling studies revealed no change in the bone formation rates in A(1)R-knockout mice. CONCLUSION These results suggest that the adenosine A(1) receptor may be a useful target in treating diseases characterized by excessive bone turnover, such as osteoporosis and prosthetic joint loosening.
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Affiliation(s)
- Firas M Kara
- New York University School of Medicine, New York, NY, USA
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147
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Anti-metabolic syndrome effects of adenosine ingestion in stroke-prone spontaneously hypertensive rats fed a high-fat diet. Br J Nutr 2010; 104:48-55. [PMID: 20175942 DOI: 10.1017/s0007114510000255] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We have demonstrated previously that both acute and chronic oral administration of adenosine have novel functions such as anti-hypertensive effects and improved hyperlipidaemia in stroke-prone spontaneously hypertensive rats (SHRSP) fed a normal diet. The purpose of the present study was to investigate the effect of adenosine administration on metabolic syndrome-related parameters in SHRSP fed a high-fat diet. Six-week-old rats were divided into three groups, and were administered either water (control) or adenosine (10 or 100 mg/l) for 8 weeks. During this period, the rats had free access to a high-fat diet based on AIN-93M. The results showed that hypertension, plasma lipid, NO, insulin, glucose and urinary 8-hydroxy-2'-deoxyguanosine levels improved significantly in both adenosine groups. The mRNA expression levels of genes involved in anti-oxidative activity and adenosine receptors were also altered in the adenosine groups. Administration of adenosine also increased plasma adiponectin levels, accompanied by upregulation of mRNA expression level of adiponectin and adiponectin receptor 1 in perirenal fat and adiponectin receptor 2 in the liver. In conclusion, oral administration of adenosine is effective for improving metabolic syndrome-related parameters in SHRSP, and accordingly it may prevent the progression of the metabolic syndrome.
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Wang H, Zhang W, Tang R, Zhu C, Bucher C, Blazar BR, Geng JG, Zhang C, Linden J, Wu C, Huo Y. Adenosine receptor A2A deficiency in leukocytes increases arterial neointima formation in apolipoprotein E-deficient mice. Arterioscler Thromb Vasc Biol 2010; 30:915-22. [PMID: 20167656 DOI: 10.1161/atvbaha.109.202572] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE To use the mice deficient in both adenosine receptor A(2A)(A(2A)R(-/-)) and apolipoprotein E (apoE(-/-)) to investigate the role of A(2A)R in mediating the interactions of leukocytes with injured arterial walls and the formation of arterial neointima induced by a guide wire. METHODS AND RESULTS In apoE(-/-) mice, A(2A)R deficiency increased the size of the arterial neointima in injured carotid arteries by 83%. Arterial neointima formation was also enhanced in chimeric mice that underwent bone marrow transplantation (these mice lacked A(2A)R in their bone marrow-derived cells). Epifluorescence intravital microscopy showed that neutrophil rolling and adherence to the injured arterial area were enhanced by 80% and 110% in A(2A)R(-/-)/apoE(-/-) mice, respectively. This phenomenon occurred even though the protein levels of homing molecules on A(2A)R-deficient neutrophils were unchanged from those of wild-type neutrophils. A(2A)R-deficient neutrophils exhibited an increase in the phosphorylation of p38 mitogen-activated protein kinase, P-selectin glycoprotein ligand-1 (PSGL-1) clustering, and the affinity of b(2) integrins. The inhibition of p38 phosphorylation abrogated the increased PSGL-1 clustering and beta(2) integrin affinity, thus reversing the increased homing ability of A(2A)R-deficient leukocytes. CONCLUSION A(2A)R plays a complex role in inflammation and tissue injury. The deficiency of A(2A)R enhances the homing ability of leukocytes and increases the formation of the arterial neointima after injury. A(2A)R antagonists are being tested for the treatment of neurodegenerative and other chronic diseases. An evaluation of the effect of A(2A)R antagonists on arterial restenosis after arterial angioplasty should be conducted.
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Affiliation(s)
- Huan Wang
- Department of Medicine, University of Minnesota, Minneapolis, USA
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Shin JW, Wang JH, Kang JK, Son CG. Experimental evidence for the protective effects of coffee against liver fibrosis in SD rats. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2010; 90:450-455. [PMID: 20355067 DOI: 10.1002/jsfa.3838] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND Coffee is one of the most commonly consumed beverages worldwide. Accumulating clinical evidence has shown an inverse relationship between coffee and liver cirrhosis. We investigated the protective effect of coffee against liver fibrosis and underlying molecular mechanisms using a dimethylnitrosamine (DMN)-induced liver fibrosis model. RESULTS Coffee administration significantly prevented the deterioration of body weight, organ weight, and serum biochemistry by DMN treatment. Histopathological examination revealed that necrosis/inflammation and fibrotic septa decreased significantly in coffee-treated rats compared to those treated with DMN and water. Coffee administration also significantly inhibited the accumulation of hydroxyproline (P < 0.001) and the production of malondialdehyde (P < 0.05), as well as stellate cell activation caused by DMN injection. Coffee protected the depletion of glutathione, superoxide dismutase, and catalase in liver tissue. In addition, coffee treatment inhibited the gene expression of inducible nitric oxide synthase, transforming growth factor (TGF)-beta, tumor necrosis factor-alpha, interleukin-1, and platelet-derived growth factor (PDGF)-beta in liver tissues, and lowered the concentration of TGF-beta and PDGF-beta in liver. Coffee inhibited NO production by macrophages. CONCLUSION Coffee exerts protective effects against liver fibrosis via antioxidant action and the suppression of fibrogenic cytokines, TGF-beta and PDGF-beta.
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Affiliation(s)
- Jang-Woo Shin
- East-West Immune Center, Institute of Traditional Medicine and Bioscience of Daejeon University, Daejeon 301-724, Republic of Korea
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Yang P, Han Z, Chen P, Zhu L, Wang S, Hua Z, Zhang J. A contradictory role of A1 adenosine receptor in carbon tetrachloride- and bile duct ligation-induced liver fibrosis in mice. J Pharmacol Exp Ther 2009; 332:747-54. [PMID: 20007753 DOI: 10.1124/jpet.109.162727] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mice lacking A(1) adenosine receptors (A(1)AR) were thought to be protected from developing fatty liver; however, the contribution of A(1)AR to hepatic fibrosis has not been explored. Here we found that the expression of A(1)AR was decreased in fibrotic liver induced by chronic carbon tetrachloride (CCl(4)) but increased in that induced by bile duct ligation (BDL). Therefore, we examined whether A(1)AR contributes to hepatic fibrosis in CCl(4) and BDL animal models using A(1)AR knockout mice. Compared with wild-type (WT) mice, hepatic fibrosis resulting from chronic CCl(4) exposure was attenuated in A(1)AR(-/-) mice with markedly decreased collagen deposition and reduced hepatic stellate cell activation, whereas bile duct-ligated A(1)AR(-/-) mice displayed a significant increase in hepatic fibrosis. Hepatocyte damage was reduced in A(1)AR(-/-) mice after a single injection of CCl(4), with down-regulation of CYP2E1 and UCP2 gene expression in livers, which resulted in impaired liver sensitivity to CCl(4). However, BDL caused severe bile infarcts in livers of A(1)AR(-/-) mice, with significantly elevated levels of bile acid compared with those in WT mice. CCl(4) and BDL resulted in different expression patterns of genes involved in fibrogenesis in A(1)AR(-/-) mice. These results indicate that A(1)AR participates in the pathogenesis of hepatic fibrosis with a complex mechanism, and the effect of targeting adenosine and its receptors in the prevention of hepatic fibrosis should be cautiously evaluated.
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Affiliation(s)
- Ping Yang
- Center for Molecular Metabolism, Nanjing University of Science and Technology, 200 Xiaolingwei St., Nanjing 210094, China
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