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Li Y, Palmer A, Lupu L, Huber-Lang M. Inflammatory response to the ischaemia-reperfusion insult in the liver after major tissue trauma. Eur J Trauma Emerg Surg 2022; 48:4431-4444. [PMID: 35831749 DOI: 10.1007/s00068-022-02026-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 05/28/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUND Polytrauma is often accompanied by ischaemia-reperfusion injury to tissues and organs, and the resulting series of immune inflammatory reactions are a major cause of death in patients. The liver is one of the largest organs in the body, a characteristic that makes it the most vulnerable organ after multiple injuries. In addition, the liver is an important digestive organ that secretes a variety of inflammatory mediators involved in local as well as systemic immune inflammatory responses. Therefore, this review considers the main features of post-traumatic liver injury, focusing on the immuno-pathophysiological changes, the interactions between liver organs, and the principles of treatment deduced. METHODS We focus on the local as well as systemic immune response involving the liver after multiple injuries, with emphasis on the pathophysiological mechanisms. RESULTS An overview of the mechanisms underlying the pathophysiology of local as well as systemic immune responses involving the liver after multiple injuries, the latest research findings, and the current mainstream therapeutic approaches. CONCLUSION Cross-reactivity between various organs and cascade amplification effects are among the main causes of systemic immune inflammatory responses after multiple injuries. For the time being, the pathophysiological mechanisms underlying this interaction remain unclear. Future work will continue to focus on identifying potential signalling pathways as well as target genes and intervening at the right time points to prevent more severe immune inflammatory responses and promote better and faster recovery of the patient.
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Affiliation(s)
- Yang Li
- Institute for Clinical and Experimental Trauma Immunology (ITI), University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Annette Palmer
- Institute for Clinical and Experimental Trauma Immunology (ITI), University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Ludmila Lupu
- Institute for Clinical and Experimental Trauma Immunology (ITI), University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany
| | - Markus Huber-Lang
- Institute for Clinical and Experimental Trauma Immunology (ITI), University Hospital Ulm, Helmholtzstr. 8/1, 89081, Ulm, Germany.
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Corton JC, Peters JM, Klaunig JE. The PPARα-dependent rodent liver tumor response is not relevant to humans: addressing misconceptions. Arch Toxicol 2017; 92:83-119. [PMID: 29197930 DOI: 10.1007/s00204-017-2094-7] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/12/2017] [Indexed: 12/17/2022]
Abstract
A number of industrial chemicals and therapeutic agents cause liver tumors in rats and mice by activating the nuclear receptor peroxisome proliferator-activated receptor α (PPARα). The molecular and cellular events by which PPARα activators induce rodent hepatocarcinogenesis have been extensively studied elucidating a number of consistent mechanistic changes linked to the increased incidence of liver neoplasms. The weight of evidence relevant to the hypothesized mode of action (MOA) for PPARα activator-induced rodent hepatocarcinogenesis is summarized here. Chemical-specific and mechanistic data support concordance of temporal and dose-response relationships for the key events associated with many PPARα activators. The key events (KE) identified in the MOA are PPARα activation (KE1), alteration in cell growth pathways (KE2), perturbation of hepatocyte growth and survival (KE3), and selective clonal expansion of preneoplastic foci cells (KE4), which leads to the apical event-increases in hepatocellular adenomas and carcinomas (KE5). In addition, a number of concurrent molecular and cellular events have been classified as modulating factors, because they potentially alter the ability of PPARα activators to increase rodent liver cancer while not being key events themselves. These modulating factors include increases in oxidative stress and activation of NF-kB. PPARα activators are unlikely to induce liver tumors in humans due to biological differences in the response of KEs downstream of PPARα activation. This conclusion is based on minimal or no effects observed on cell growth pathways and hepatocellular proliferation in human primary hepatocytes and absence of alteration in growth pathways, hepatocyte proliferation, and tumors in the livers of species (hamsters, guinea pigs and cynomolgus monkeys) that are more appropriate human surrogates than mice and rats at overlapping dose levels. Despite this overwhelming body of evidence and almost universal acceptance of the PPARα MOA and lack of human relevance, several reviews have selectively focused on specific studies that, as discussed, contradict the consensus opinion and suggest uncertainty. In the present review, we systematically address these most germane suggested weaknesses of the PPARα MOA.
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Affiliation(s)
- J Christopher Corton
- Integrated Systems Toxicology Division, National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, 109 T.W. Alexander Dr, MD-B105-03, Research Triangle Park, NC, 27711, USA.
| | - Jeffrey M Peters
- The Department of Veterinary and Biomedical Sciences and Center for Molecular Toxicology and Carcinogenesis, The Pennsylvania State University, University Park, PA, 16803, USA
| | - James E Klaunig
- Department of Environmental Health, Indiana University, Bloomington, IN, 47402, USA
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Abstract
While reactive oxygen species (ROS) gain their carcinogenic effects by DNA mutations, if generated in the vicinity of genome, lipid peroxidation products, notably 4-hydroxynonenal (HNE), have much more complex modes of activities. Namely, while ROS are short living and have short efficiency distance range (in nm or µm) HNE has strong binding affinity for proteins, thus forming relatively stable adducts. Hence, HNE can diffuse from the site or origin changing structure and function of respective proteins. Consequently HNE can influence proliferation, differentiation and apoptosis of cancer cells on one hand, while on the other it can affect genome functionality, too. Although HNE is considered to be important factor of carcinogenesis due to its ability to covalently bind to DNA, it might also be cytotoxic for cancer cells, as well as it can modulate their growth. In addition to direct cytotoxicity, HNE is also involved in activity mechanisms by which several cytostatic drugs and radiotherapy exhibit their anticancer effects. Complementary to that, the metabolic pathway for HNE detoxification through RLIP76, which is enhanced in cancer, may be a target for anti-cancer treatments. In addition, some cancer cells can undergo apoptosis or necrosis, if exposed to supraphysiological HNE levels in the cancer microenvironment, especially if challenged additionally by pro-oxidative cytostatics and/or inflammation. These findings could explain previously observed disappearance of HNE from invading cancer cells, which is associated with the increase of HNE in non-malignant cells close to invading cancer utilizing cardiolipin as the source of cancer-inhibiting HNE.
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Affiliation(s)
| | | | | | - Neven Zarkovic
- Rudjer Boskovic Institute, Bijenicka 54, Zagreb, Croatia.
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Luo JY, Li XM, Zhou Y, Zhao Q, Chen BD, Liu F, Chen XC, Zheng H, Ma YT, Gao XM, Yang YN. Mutant DD genotype of NFKB1 gene is associated with the susceptibility and severity of coronary artery disease. J Mol Cell Cardiol 2017; 103:56-64. [PMID: 28088561 DOI: 10.1016/j.yjmcc.2017.01.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 12/22/2016] [Accepted: 01/10/2017] [Indexed: 12/18/2022]
Abstract
Nuclear factor κappa B (NF-κB) is an important transcription factor in the development and progression of coronary artery disease (CAD). Recent evidence suggests that -94 ATTG ins/del mutant in the promoter of NFKB1 gene is an essential functional mutant. The present study demonstrated the frequencies of the del/del (DD) genotype and del (D) allele were significantly higher in CAD patients than in controls. CAD patients carrying mutant DD genotype had worse stenosis of diseased coronary arteries compared to those carrying ins/ins (II) or ins/del (ID) genotype. Plasma levels of endothelial nitric oxide synthase (eNOS) were lower, while inflammatory cytokine incnterlukin-6 (IL-6) was higher in CAD patients with DD genotype than those with II or ID genotype (both P<0.05). In vitro study showed that mutant human umbilical vein endothelial cells (DD genotype HUVECs) were more susceptible to H2O2-induced apoptosis, which was accompanied with a decreased Bcl-2 expression. Further, mutant HUVECs had lower eNOS but higher IL-6 mRNA levels and decreased phosphorylation of eNOS under H2O2-stimulation (both P<0.05). Compared to wild type cells (II genotype), significantly downregulated protein expression of total NF-κB p50 subunit were observed in mutant HUVECs with or without oxidative stress, and a lower expression of unclear p50 was associated with a decreased p50 nuclear translocation in mutant HUVECs versus wild type cells under H2O2-stimulation (both P<0.05). In conclusion, mutant DD genotype of NFKB1 gene is associated with the risk and severity of CAD. Dwonregulation of NF-κB p50 subunit leads to exacerbated endothelial dysfunction and apoptosis and enhanced inflammatory response that is the potential underlying mechanism.
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Affiliation(s)
- Jun-Yi Luo
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Xiao-Mei Li
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yun Zhou
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Qiang Zhao
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Bang-Dang Chen
- Xinjiang Key Laboratory of Cardiovascular Research, Urumqi, Xinjiang, China
| | - Fen Liu
- Xinjiang Key Laboratory of Cardiovascular Research, Urumqi, Xinjiang, China
| | - Xiao-Cui Chen
- Xinjiang Key Laboratory of Cardiovascular Research, Urumqi, Xinjiang, China
| | - Hong Zheng
- Department of Anaesthesiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yi-Tong Ma
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China.
| | - Xiao-Ming Gao
- Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia; Xinjiang Key Laboratory of Medical Animal Model Research, Urumqi, Xinjiang, China; Department of Surgery, Central Clinical School, Monash University, Melbourne, Victoria, Australia.
| | - Yi-Ning Yang
- Department of Cardiology, First Affiliated Hospital of Xinjiang Medical University, Urumqi, Xinjiang, China.
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Corton JC, Cunningham ML, Hummer BT, Lau C, Meek B, Peters JM, Popp JA, Rhomberg L, Seed J, Klaunig JE. Mode of action framework analysis for receptor-mediated toxicity: The peroxisome proliferator-activated receptor alpha (PPARα) as a case study. Crit Rev Toxicol 2013; 44:1-49. [PMID: 24180432 DOI: 10.3109/10408444.2013.835784] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Several therapeutic agents and industrial chemicals induce liver tumors in rodents through the activation of the peroxisome proliferator-activated receptor alpha (PPARα). The cellular and molecular events by which PPARα activators induce rodent hepatocarcinogenesis has been extensively studied and elucidated. This review summarizes the weight of evidence relevant to the hypothesized mode of action (MOA) for PPARα activator-induced rodent hepatocarcinogenesis and identifies gaps in our knowledge of this MOA. Chemical-specific and mechanistic data support concordance of temporal and dose-response relationships for the key events associated with many PPARα activators including a phthalate ester plasticizer di(2-ethylhexyl) phthalate (DEHP) and the drug gemfibrozil. While biologically plausible in humans, the hypothesized key events in the rodent MOA, for PPARα activators, are unlikely to induce liver tumors in humans because of toxicodynamic and biological differences in responses. This conclusion is based on minimal or no effects observed on growth pathways, hepatocellular proliferation and liver tumors in humans and/or species (including hamsters, guinea pigs and cynomolgous monkeys) that are more appropriate human surrogates than mice and rats at overlapping dose levels. Overall, the panel concluded that significant quantitative differences in PPARα activator-induced effects related to liver cancer formation exist between rodents and humans. On the basis of these quantitative differences, most of the workgroup felt that the rodent MOA is "not relevant to humans" with the remaining members concluding that the MOA is "unlikely to be relevant to humans". The two groups differed in their level of confidence based on perceived limitations of the quantitative and mechanistic knowledge of the species differences, which for some panel members strongly supports but cannot preclude the absence of effects under unlikely exposure scenarios.
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Tharappel JC, Ramineni SK, Reynolds D, Puleo DA, Roth JS. Doxycycline impacts hernia repair outcomes. J Surg Res 2013; 184:699-704. [PMID: 23830364 DOI: 10.1016/j.jss.2013.05.101] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Revised: 05/23/2013] [Accepted: 05/30/2013] [Indexed: 11/21/2022]
Abstract
BACKGROUND Incisional hernias occur commonly in up to 20% of all abdominal operations. Incisional hernia formation has been associated with increased levels of matrix metalloproteinases (MMPs), reduced collagen 1, and increased collagen 3 expression. Doxycycline, a nonspecific inhibitor of MMPs, has been shown to beneficially reduce MMP levels in both cancer and aneurysm models. This study evaluates the impact of doxycycline upon MMP expression, collagen subtypes, and hernia repair distraction forces in an animal model of incisional hernia repair. MATERIALS AND METHODS Twenty-four Sprague Dawley rats underwent incisional hernia creation and subsequent repair with polypropylene mesh. Animals were administered doxycycline or saline daily beginning 1 d prior to hernia repair and survived for 1, 2, or 4 wk. Serum and tissue were evaluated for MMP content and collagen subtyping utilizing enzyme-linked immunosorbent assay and Western blot. Tensiometric properties of the native abdominal wall after hernia repair were measured with an Instron Corp. (Canton, MA) mechanical testing system. RESULTS There were no differences in control and experimental groups 1 and 2 wk following hernia repair; 4 wk following hernia repair, doxycycline treated animals demonstrated reduced serum MMP-2 and MMP-9 levels, reduced tissue levels of MMP-2, MMP-3, and MMP-9, and increased collagen 1 to 3 ratios. Distraction forces required to disrupt the hernia repair were increased in the doxycycline treated group compared with controls. CONCLUSIONS Doxycycline administration is associated with improved hernia repair strength with concomitant reduction of MMP levels with increased collagen 1 deposition. Longer term studies are required to better understand the impact of this treatment.
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Li J, Harp C, Tharappel JC, Spear BT, Glauert HP. Effect of vitamin E on hepatic cell proliferation and apoptosis in mice deficient in the p50 subunit of NF-κB after treatment with phenobarbital. Food Chem Toxicol 2011; 49:2706-9. [PMID: 21726593 DOI: 10.1016/j.fct.2011.06.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2011] [Revised: 06/17/2011] [Accepted: 06/19/2011] [Indexed: 12/21/2022]
Abstract
Phenobarbital (PB) is an efficacious and well-studied hepatic tumor promoting agent. Nuclear factor-κB (NF-κB) is a transcription factor activated by reactive oxygen and is involved in cell proliferation and apoptosis. We previously found that PB activates NF-κB and that dietary vitamin E is effective in decreasing PB-induced NF-κB DNA binding. We therefore hypothesized that dietary vitamin E influences PB-induced changes in cell proliferation and apoptosis through its action on NF-κB. NF-κB1 deficient mice (p50-/-) and wild-type B6129 mice were fed a purified diet containing 10 or 250ppm vitamin E (α-tocopherol acetate) for 28days. At that time, half of the wild-type and half of the p50-/- mice were placed on the same diet with 0.05% PB for 10days. Compared to wild-type mice, the p50-/- mice had higher levels of cell proliferation and apoptosis. Cell proliferation was significantly increased by PB, but vitamin E did not affect hepatic cell proliferation. Apoptosis was not changed in mice fed PB, and there was no significant difference in apoptosis between control and high vitamin E treated mice. Thus, vitamin E does not appear to influence cell growth parameters in either wild-type or p50-/- mice.
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Gao Z, Yin J, Zhang J, He Q, McGuinness OP, Ye J. Inactivation of NF-kappaB p50 leads to insulin sensitization in liver through post-translational inhibition of p70S6K. J Biol Chem 2009; 284:18368-76. [PMID: 19433583 DOI: 10.1074/jbc.m109.007260] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In this study, we investigated the metabolic phenotype of the NF-kappaB p50 knock-out (p50-KO) mice. Compared with wild type mice, the p50-KO mice had an increase in food intake, but a decrease in body fat content. On chow diet, their blood glucose dropped much more than the wild type (WT) mice in the insulin tolerance test. Their glucose infusion rate was 30% higher than that of the WT mice in the hyperinsulinemic-euglycemic clamp. Their hepatic glucose production was suppressed more actively by insulin, and their insulin-induced glucose uptake was not altered in skeletal muscle or adipose tissue. In the liver, their p70S6K (S6K1) protein was significantly lower, and tumor necrosis factor-alpha (TNF-alpha) expression was much higher. Their S6K1 protein was reduced by TNF-alpha treatment in the primary culture of hepatocytes. S6K1 reduction was blocked by the proteasome inhibitor MG132. In their livers, IKK2 (IKKbeta) activity was reduced together with IKKgamma. Their S6K1 degradation was dependent on IKK2 deficiency. Reconstitution of the S6K1 protein in their liver blocked the increase in insulin sensitivity. S6K1 degradation was not observed in hepatocytes of the WT mice. The data suggest that inactivation of NF-kappaB p50 leads to suppression of IKK2 activity in the liver. IKK2 deficiency leads to S6K1 inhibition through TNF-induced protein degradation. The S6K1 reduction may contribute to insulin sensitivity in p50-KO mice. This study suggests that hepatic S6K1 may be a drug target in the treatment of insulin resistance.
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Affiliation(s)
- Zhanguo Gao
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana 70808, USA
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Glauert HP, Calfee-Mason K, Li Y, Nilakantan V, Twaroski ML, Tharappel J, Spear BT. The Role of NF-kappaB in PPARalpha-Mediated Hepatocarcinogenesis. PPAR Res 2008; 2008:286249. [PMID: 19197377 DOI: 10.1155/2008/286249] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Revised: 10/03/2008] [Accepted: 11/03/2008] [Indexed: 01/04/2023] Open
Abstract
In this review, the role of NF-kappaB in the induction of hepatocarcinogenesis by peroxisome proliferators is examined. The administration of peroxisome proliferators for more than a three-day period leads to the activation of NF-kappaB in the livers of rats and mice. On the other hand, peroxisome proliferator activated receptor-alpha (PPARalpha) activation in non-hepatic tissues can lead to the inhibition of NF-kappaB activation. Several lines of evidence support the hypothesis that the activation of NF-kappaB by peroxisome proliferators in the liver is mediated by oxidative stress. The role of NF-kappaB in peroxisome proliferator-induced hepatocarcinogenesis has been examined using NF-kappaB knockout models. Specifically, the induction of cell proliferation and the promotion of liver carcinogenesis are inhibited in mice lacking the p50 subunit of NF-kappaB. Overall, the activation of NF-kappaB appears to be important in the carcinogenic activity of peroxisome proliferators.
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Abstract
In this review, the evidence about the role of oxidative stress in the induction of hepatocellular carcinomas by peroxisome proliferators is examined. The activation of PPAR-alpha by peroxisome proliferators in rats and mice may produce oxidative stress, due to the induction of enzymes like fatty acyl coenzyme A (CoA) oxidase (AOX) and cytochrome P-450 4A1. The effect of peroxisome proliferators on the antioxidant defense system is reviewed, as is the effect on endpoints resulting from oxidative stress that may be important in carcinogenesis, such as lipid peroxidation, oxidative DNA damage, and transcription factor activation. Peroxisome proliferators clearly inhibit several enzymes in the antioxidant defense system, but studies examining effects on lipid peroxidation and oxidative DNA damage are conflicting. There is a profound species difference in the induction of hepatocellular carcinomas by peroxisome proliferators, with rats and mice being sensitive, whereas species such as nonhuman primates and guinea pigs are not susceptible to the effects of peroxisome proliferators. The possible role of oxidative stress in these species differences is also reviewed. Overall, peroxisome proliferators produce changes in oxidative stress, but whether these changes are important in the carcinogenic process is not clear at this time.
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Affiliation(s)
- Michelle L O'Brien
- Graduate Centerfor Toxicology, University of Kentucky, Lexington, Kentucky 40506-0054, USA
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Calfee-Mason KG, Lee EY, Spear BT, Glauert HP. Role of the p50 subunit of NF-kappaB in vitamin E-induced changes in mice treated with the peroxisome proliferator, ciprofibrate. Food Chem Toxicol 2008; 46:2062-73. [PMID: 18336980 PMCID: PMC2600965 DOI: 10.1016/j.fct.2008.01.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 10/01/2007] [Accepted: 01/28/2008] [Indexed: 12/18/2022]
Abstract
Peroxisome proliferators (PPs) are a diverse class of chemicals, which cause a dramatic increase in the size and number of hepatic peroxisomes in rodents and eventually lead to the development of hepatic tumors. Nuclear factor-kappaB (NF-kappaB) is a transcription factor activated by reactive oxygen and is involved in cell proliferation and apoptosis. Previously we found that the peroxisome proliferator ciprofibrate (CIP) activates NF-kappaB and that dietary vitamin E decreases CIP-induced NF-kappaB DNA binding. We, therefore, hypothesized that inhibition of NF-kappaB by vitamin E is necessary for effects of vitamin E on CIP-induced cell proliferation and the inhibition of apoptosis by CIP. Sixteen B6129 female mice (p50+/+) and twenty mice deficient in the p50 subunit of NF-kappaB (p50-/-) were fed a purified diet containing 10 or 250mg/kg vitamin E (alpha-tocopherol acetate) for 28 days. At that time, half of the mice were placed on the same diet with 0.01% CIP for 10 days. CIP treatment increased the DNA binding activity of NF-kappaB and cell proliferation, but had no significant effect on apoptosis. Compared to wild-type mice, the p50-/- mice had lower NF-kappaB activation, higher basal levels of cell proliferation and apoptosis, and a lower ratio of reduced glutathione to oxidized glutathione (GSH/GSSG). There was approximately a 60% reduction in cell proliferation in the CIP-treated p50-/- mice fed higher vitamin E in comparison to the p50-/- mice fed lower vitamin E. Dietary vitamin E also inhibited the DNA binding activity of NF-kappaB, increased apoptosis, and increased the GSH/GSSG ratio. This study shows the effects of vitamin E on cell growth parameters do not appear to be solely through decreased NF-kappaB activation, suggesting that vitamin E is acting by other molecular mechanisms.
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Affiliation(s)
- Karen G. Calfee-Mason
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40506, USA
| | - Eun Y. Lee
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY 40506, USA
| | - Brett T. Spear
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40506, USA
- Department of Pathology and Laboratory Medicine, University of Kentucky, Lexington, KY 40506, USA
- Department of Microbiology, Immunology and Molecular Genetics, University of Kentucky, Lexington, KY 40506, USA
- Graduate Center for Toxicology; University of Kentucky, Lexington, KY 40506, USA
| | - Howard P. Glauert
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40506, USA
- Graduate Center for Toxicology; University of Kentucky, Lexington, KY 40506, USA
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Tharappel JC, Spear BT, Glauert HP. Effect of phenobarbital on hepatic cell proliferation and apoptosis in mice deficient in the p50 subunit of NF-kappaB. Toxicol Appl Pharmacol 2007; 226:338-44. [PMID: 17963809 DOI: 10.1016/j.taap.2007.09.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 09/13/2007] [Accepted: 09/19/2007] [Indexed: 01/09/2023]
Abstract
Phenobarbital (PB) is a nongenotoxic tumor promoter in the liver. One mechanism by which PB may exert its tumor promoting activity is by inducing oxidative stress. We previously found that PB administration increased hepatic NF-kappaB DNA binding activity. In this study we examined the hypothesis that the effects of PB on cell proliferation and apoptosis are dependent on NF-kappaB. We used a mouse model that is deficient in the p50 subunit of NF-kappaB; previous studies had found that p50-/- mice were less sensitive to the induction of hepatic cell proliferation by PCBs or peroxisome proliferators. Mice (p50-/- and wild-type B6129) were fed a control diet or one containing 0.05% PB for 3, 10 or 34 days. At the end of the experiment, the mice were euthanized and livers removed and processed. PB increased cell proliferation at 3 and 10 days (but not at 34 days), but the deletion of the NF-kappaB p50 subunit did not inhibit these increases. p50-/- Mice had higher cell proliferation at the 3 day (only in mice fed PB) and 34-day timepoints. PB decreased hepatocyte apoptosis after 3 days, slightly decreased it after 10 days, and did not affect it after 34 days. The deletion of the NF-kappaB p50 subunit did not influence PB's effect on apoptosis. In p50-/- mice, apoptosis was increased after 3 or 10 days compared to wild-type mice, but no effect was seen after 34 days. The hepatic expression of the NF-kappaB-regulated gene TNF-alpha correlated more with the hepatic cell proliferation data than with hepatic apoptosis, and was not decreased by the deletion of the p50 subunit. These findings show that the p50 subunit of NF-kappaB is not required for the alteration of hepatocyte proliferation or apoptosis by PB up to 34 days after its administration.
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Affiliation(s)
- Job C Tharappel
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40506-0054, USA
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Luci S, Giemsa B, Hause G, Kluge H, Eder K. Clofibrate treatment in pigs: effects on parameters critical with respect to peroxisome proliferator-induced hepatocarcinogenesis in rodents. BMC Pharmacol 2007; 7:6. [PMID: 17437637 DOI: 10.1186/1471-2210-7-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Accepted: 04/16/2007] [Indexed: 11/25/2022] Open
Abstract
Background In rodents treatment with fibrates causes hepatocarcinogenesis, probably as a result of oxidative stress and an impaired balance between apoptosis and cell proliferation in the liver. There is some debate whether fibrates could also induce liver cancer in species not responsive to peroxisome proliferation. In this study the effect of clofibrate treatment on peroxisome proliferation, production of oxidative stress, gene expression of pro- and anti-apoptotic genes and proto-oncogenes was investigated in the liver of pigs, a non-proliferating species. Results Pigs treated with clofibrate had heavier livers (+16%), higher peroxisome counts (+61%), higher mRNA concentration of acyl-CoA oxidase (+66%), a higher activity of catalase (+41%) but lower concentrations of hydrogen peroxide (-32%) in the liver than control pigs (P < 0.05); concentrations of lipid peroxidation products (thiobarbituric acid-reactive substances, conjugated dienes) and total and reduced glutathione in the liver did not differ between both groups. Clofibrate treated pigs also had higher hepatic mRNA concentrations of bax and the proto-oncogenes c-myc and c-jun and a lower mRNA concentration of bcl-XL than control pigs (P < 0.05). Conclusion The data of this study show that clofibrate treatment induces moderate peroxisome proliferation but does not cause oxidative stress in the liver of pigs. Gene expression analysis indicates that clofibrate treatment did not inhibit but rather stimulated apoptosis in the liver of these animals. It is also shown that clofibrate increases the expression of the proto-oncogenes c-myc and c-jun in the liver, an event which could be critical with respect to carcinogenesis. As the extent of peroxisome proliferation by clofibrate was similar to that observed in humans, the pig can be regarded as a useful model for investigating the effects of peroxisome proliferators on liver function and hepatocarcinogenesis.
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Sunder‐Plassmann R. Cytochrome P450: Another Player in the Myocardial Infarction Game? Adv Clin Chem 2007. [DOI: 10.1016/s0065-2423(06)43008-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Abstract
Nuclear factor (NF-kappaB)(1) is a eukaryotic transcription factor that may be activated by oxidative stress. Because of this hypothesis, the effect of vitamin E on NF-kappaB activation has been examined in many studies, using both in vivo and in vitro models. Most of these studies have observed that vitamin E inhibits the activation of NF-kappaB, with the greatest inhibition seen with the succinate form. Vitamin E may be inhibiting NF-kappaB by reducing oxidative stress or through one of its nonantioxidant functions; this is not clear at the present time. It also is not known if the inhibition of NF-kappaB is necessary for any of vitamin E's effects on gene expression and the resulting physiological effects.
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Affiliation(s)
- Howard P Glauert
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40506, USA
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16
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Glauert HP, Eyigor A, Tharappel JC, Cooper S, Lee EY, Spear BT. Inhibition of hepatocarcinogenesis by the deletion of the p50 subunit of NF-kappaB in mice administered the peroxisome proliferator Wy-14,643. Toxicol Sci 2006; 90:331-6. [PMID: 16434500 DOI: 10.1093/toxsci/kfj116] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Wy-14,643 (WY) is a hypolipidemic drug that induces hepatic peroxisome proliferation and tumors in rodents. We previously showed that peroxisome proliferators increase NF-kappaB DNA binding activity in rats, mice, and hepatoma cell lines, and that mice deficient in the p50 subunit of NF-kappaB had much lower cell proliferation in response to the peroxisome proliferator ciprofibrate. In this study we examined the promotion of hepatocarcinogenesis by WY in the p50 knockout (-/-) mice. The p50 -/- and wild type mice were first administered diethylnitrosamine (DEN) as an initiating agent. Mice were then fed a control diet or a diet containing 0.05% WY for 38 weeks. Wild-type mice receiving DEN only developed a low incidence of tumors, and the majority of wild-type mice receiving both DEN and WY developed tumors. However, no tumors were seen in any of the p50 -/- mice. Cell proliferation and apoptosis were measured in hepatocytes by BrdU labeling and the TUNEL assay, respectively. Treatment with DEN + WY increased both cell proliferation and apoptosis in both the wild-type and p50 -/- mice; DEN treatment alone has no effect. In the DEN/WY-treated mice, cell proliferation and apoptosis were slightly lower in the p50 -/- mice than in the wild-type mice. These data demonstrate that NF-kappaB is involved in the promotion of hepatic tumors by the peroxisome proliferator WY; however, the difference in tumor incidence could not be attributed to alterations in either cell proliferation or apoptosis.
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Affiliation(s)
- Howard P Glauert
- Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, Kentucky 40506, USA.
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17
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Cariello NF, Romach EH, Colton HM, Ni H, Yoon L, Falls JG, Casey W, Creech D, Anderson SP, Benavides GR, Hoivik DJ, Brown R, Miller RT. Gene expression profiling of the PPAR-alpha agonist ciprofibrate in the cynomolgus monkey liver. Toxicol Sci 2005; 88:250-64. [PMID: 16081524 DOI: 10.1093/toxsci/kfi273] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Fibrates, such as ciprofibrate, fenofibrate, and clofibrate, are peroxisome proliferator-activated receptor-alpha (PPARalpha) agonists that have been in clinical use for many decades for treatment of dyslipidemia. When mice and rats are given PPARalpha agonists, these drugs cause hepatic peroxisome proliferation, hypertrophy, hyperplasia, and eventually hepatocarcinogenesis. Importantly, primates are relatively refractory to these effects; however, the mechanisms for the species differences are not clearly understood. Cynomolgus monkeys were exposed to ciprofibrate at various dose levels for either 4 or 15 days, and the liver transcriptional profiles were examined using Affymetrix human GeneChips. Strong upregulation of many genes relating to fatty acid metabolism and mitochondrial oxidative phosphorylation was observed; this reflects the known pharmacology and activity of the fibrates. In addition, (1) many genes related to ribosome and proteasome biosynthesis were upregulated, (2) a large number of genes downregulated were in the complement and coagulation cascades, (3) a number of key regulatory genes, including members of the JUN, MYC, and NFkappaB families were downregulated, which appears to be in contrast to the rodent, where JUN and MYC are reported to upregulated after PPARalpha agonist treatment, (4) no transcriptional signal for DNA damage or oxidative stress was observed, and (5) transcriptional signals consistent with an anti-proliferative and a pro-apoptotic effect were seen. We also compared the primate data to literature reports of hepatic transcriptional profiling in PPARalpha-treated rodents, which showed that the magnitude of induction in beta-oxidation pathways was substantially greater in the rodent than the primate.
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Affiliation(s)
- Neal F Cariello
- GlaxoSmithKline Inc., Safety Assessment, Research Triangle Park, North Carolina 27709, USA.
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