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Bakshi S, Kaur M, Verma A, Sharma S. Molecular and cellular remodeling of HepG2 cells upon treatment with antitubercular drugs. J Biochem Mol Toxicol 2023; 37:e23386. [PMID: 37254945 DOI: 10.1002/jbt.23386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 02/20/2023] [Accepted: 05/17/2023] [Indexed: 06/01/2023]
Abstract
Drug-induced liver injury (DILI) is an adverse outcome of the currently used tuberculosis treatment regimen, which results in patient noncompliance, poor treatment outcomes, and the emergence of drug-resistant tuberculosis. DILI is primarily caused by the toxicity of the drugs and their metabolites, which affect liver cells, biliary epithelial cells, and liver vasculature. However, the precise mechanism behind the cellular damage attributable to first-line antitubercular drugs (ATDs), as well as the effect of toxicity on the cell survival strategies, is yet to be elucidated. In the current study, HepG2 cells upon treatment with a high concentration of ATDs showed increased perforation within the cell, cuboidal shape, and membrane blebbing as compared with control/untreated cells. It was observed that ATD-induced toxicity in HepG2 cells leads to altered mitochondrial membrane permeability, which was depicted by the decreased fluorescence intensity of the MitoRed tracker dye at higher drug concentrations. In addition, high doses of ATDs caused cell damage through an increase in reactive oxygen species production in HepG2 cells and a simultaneous reduction in glutathione levels. Further, high dose of isoniazid (50-200 mM), pyrazinamide (50-200 mM), and rifampicin (20-100 µM) causes cell apoptosis and affects cell survival during toxic conditions by decreasing the expression of potent autophagy markers Atg5, Atg7, and LC3B. Thus, ATD-mediated toxicity contributes to the reduced ability of hepatocytes to tolerate cellular damage caused by altered mitochondrial membrane permeability, increased apoptosis, and decreased autophagy. These findings further emphasize the need to develop adjuvant therapies that can mitigate ATD-induced toxicity for the effective treatment of tuberculosis.
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Affiliation(s)
- Shikha Bakshi
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Maninder Kaur
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Arpana Verma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
| | - Sadhna Sharma
- Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India
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Wakayama T, Ito Y, Sakai K, Miyake M, Shibata E, Ohno H, Kamijima M. Comprehensive review of 2-ethyl-1-hexanol as an indoor air pollutant. J Occup Health 2019; 61:19-35. [PMID: 30698348 PMCID: PMC6499367 DOI: 10.1002/1348-9585.12017] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/02/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
Objectives 2‐Ethyl‐1‐hexanol (2EH), a fragrance ingredient and a raw material for the production of plasticizer di(2‐ethylhexyl) phthalate, is responsible for sick building syndrome (SBS). This review aims to clarify the 2EH characteristics as an indoor air pollutant such as indoor air concentration, emission mechanism, toxicity, and clinical effects. Methods Scientific publications in English that has been made available on PubMed as of June 2018 and ad hoc publications in regional languages were reviewed. Results Inhalation exposure to 2EH caused mucous membrane irritation in the eyes, nose, and throat in experimental animals. Studies in human volunteers revealed an increase in olfactory irritation and eye discomfort. There has been increasing evidence of 2EH being present in indoor air in buildings. The primary sources of 2EH emissions are not building materials themselves, but instead the hydrolysis of plasticizers and flooring adhesives. In particular, compounds like di(2‐ethylhexyl) phthalate present in polyvinyl chloride flooring materials are hydrolyzed upon contact with alkaline moisture‐containing concrete floors. That being said, it may be observed that indoor concentrations of 2EH increased every year during summer. Conclusions Unlike other volatile organic compounds that cause SBS, 2EH can be retained in indoor air for long durations, increasing the likelihood of causing undesirable health effects in building occupants exposed to it. As a precautionary measure, it is important to use flooring materials that do not emit 2EH by hydrolysis, or to dry concrete before covering with flooring materials.
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Affiliation(s)
- Takanari Wakayama
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Department of Environmental Health, Nagoya City Public Health Research Institute, Nagoya, Japan
| | - Yuki Ito
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Kiyoshi Sakai
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.,Department of Environmental Health, Nagoya City Public Health Research Institute, Nagoya, Japan
| | - Mio Miyake
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Eiji Shibata
- Department of Health and Psychosocial Medicine, Aichi Medical University School of Medicine, Nagakute, Japan
| | - Hiroyuki Ohno
- Department of Environmental Health, Nagoya City Public Health Research Institute, Nagoya, Japan
| | - Michihiro Kamijima
- Department of Occupational and Environmental Health, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
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3
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Nelms MD, Mellor CL, Cronin MTD, Madden JC, Enoch SJ. Development of an in Silico Profiler for Mitochondrial Toxicity. Chem Res Toxicol 2015; 28:1891-902. [PMID: 26375963 DOI: 10.1021/acs.chemrestox.5b00275] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
This study outlines the analysis of mitochondrial toxicity for a variety of pharmaceutical drugs extracted from Zhang et al. ((2009) Toxicol. In Vitro, 23, 134-140). These chemicals were grouped into categories based upon structural similarity. Subsequently, mechanistic analysis was undertaken for each category to identify the molecular initiating event driving mitochondrial toxicity. The mechanistic information elucidated during the analysis enabled mechanism-based structural alerts to be developed and combined together to form an in silico profiler. This profiler is envisaged to be used to develop chemical categories based upon similar mechanisms as part of the adverse outcome pathway paradigm. Additionally, the profiler could be utilized in screening large data sets in order to identify chemicals with the potential to induce mitochondrial toxicity.
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Affiliation(s)
- Mark D Nelms
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, United Kingdom
| | - Claire L Mellor
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, United Kingdom
| | - Mark T D Cronin
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, United Kingdom
| | - Judith C Madden
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, United Kingdom
| | - Steven J Enoch
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University , Byrom Street, Liverpool L3 3AF, United Kingdom
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4
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Hassan HM, Guo HL, Yousef BA, Luyong Z, Zhenzhou J. Hepatotoxicity mechanisms of isoniazid: A mini-review. J Appl Toxicol 2015; 35:1427-32. [DOI: 10.1002/jat.3175] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Hozeifa M. Hassan
- Jiangsu Key Laboratory of Drug Screening; China Pharmaceutical University; Nanjing China
- Department of Pharmacology, Faculty of Pharmacy; University of Gezira; Wad-Medani Sudan
| | - Hong-li Guo
- Jiangsu Key Laboratory of Drug Screening; China Pharmaceutical University; Nanjing China
| | - Bashir A. Yousef
- Jiangsu Key Laboratory of Drug Screening; China Pharmaceutical University; Nanjing China
- Department of Pharmacology, Faculty of Pharmacy; University of Khartoum; Khartoum Sudan
| | - Zhang Luyong
- Jiangsu Key Laboratory of Drug Screening; China Pharmaceutical University; Nanjing China
- Jiangsu Center for Pharmacodynamics Research and Evaluation; China Pharmaceutical University; Nanjing China
- Jiangsu Key Laboratory of TCM Evaluation and Translational Research; China Pharmaceutical University; Nanjing China
| | - Jiang Zhenzhou
- Jiangsu Key Laboratory of Drug Screening; China Pharmaceutical University; Nanjing China
- Key Laboratory of Drug Quality Control and Pharmacovigilance (China Pharmaceutical University); Ministry of Education; Nanjing China
- State Key Laboratory of Natural Medicines; China Pharmaceutical University; Nanjing China
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Abstract
Objective: To review the mechanisms of anti-cancer activity of fenofibrate (FF) and other Peroxisome Proliferator Activator Receptor α (PPARα) agonists based on evidences reported in the published literature.Methods: We extensively reviewed the literature concerning FF as an off target anti-cancer drug. Controversies regarding conflicting findings were also addressed.Results: The main mechanism involved in anti-cancer activity is anti-angiogenesis through down-regulation of Vascular Endothelial Growth Factor (VEGF), Vascular Endothelial Growth Factor Receptor (VEGFR) and Hypoxia Inducible factor-1 α (HIF-1α), inhibition of endothelial cell migration, up-regulation of endostatin and thrombospondin-1, but there are many other contributing mechanisms like apoptosis and cell cycle arrest, down-regulation of Nuclear Factor Kappa B (NF-kB) and Protein kinase B (Akt) and decrease of cellular energy by impairing mitochondrial function. Growth impairment is related to down-regulation of Phospho-Inositol 3 Kinase (PI3K)/Akt axis and down-regulation of the p38 map kinase (MAPK) cascade. A possible role should be assigned to FF stimulated over-expression of Tribbles Homolog-3 (TRIB3) which inhibits Akt phosphorylation. Important anti-cancer and anti-metastatic activities are due to down-regulation of MCP-1 (monocyte chemotactic protein-1), decreased Metalloprotease-9 (MMP-9) production, weak down-regulation of adhesion molecules like E selectin, intercellular adhesion molecules (ICAM) and Vascular Endothelial Adhesion Molecules (VCAM), and decreased secretion of chemokines like Interleukin-6 (IL-6), and down-regulation of cyclin D-1. There is no direct link between FF activity in lipid metabolism and anticancer activity, except for the fact that many anticancer actions are dependent from PPARα agonism. FF exhibits also PPARα independent anti-cancer activities.Conclusions: There are strong evidences indicating that FF can disrupt growth-related activities in many different cancers, due to anti-angiogenesis and anti-inflammatory effects. Therefore FF may be useful as a complementary adjunct treatment of cancer, particularly included in anti-angiogenic protocols like those currently increasingly used in glioblastoma. There are sound reasons to initiate well planned phase II clinical trials for FF as a complementary adjunct treatment of cancer.
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Tunali S. The effects of vitamin B6 on lens antioxidant system in valproic acid-administered rats. Hum Exp Toxicol 2013; 33:623-8. [DOI: 10.1177/0960327113506233] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Valproic acid (VPA, 2-propyl pentanoic acid) is a broad-spectrum antiepileptic drug (AED) and is commonly used in the treatment of bipolar disorders and epilepsy. AEDs are known to result in vascular disturbances. Vitamin B6 (Vit B6) is water soluble vitamin essential for normal growth, development, and metabolism. In this study, we aimed to investigate the protective effects of Vit B6 against VPA-induced lens damage in experimental animals. In this study, male 4-month-old, Sprague-Dawley rats were used. The animals were divided into four groups. Group I was intact control animals. Group II rats were administered with Vit B6 (50 mg/kg/day) for 7 days. Group III rats were administered with only VPA (500 mg/kg/day) for 7 days. Group IV was given VPA + Vit B6 (in a same dose and time). Vit B6 was given to rats by gavage and VPA was given by intraperitoneally. On the 8th day of experiment, all of the animals were fasted overnight and then killed under ether anesthesia. Lens tissues were taken from animals, homogenized in 0.9% saline to make up a 10% homogenate. The homogenates was used for glutathione (GSH), lipid peroxidation (LPO), protein levels, and enzyme analysis. In VPA groups, levels of lens GSH and LPO and activities of glutathione- S-transferase, glutathione peroxidase, glutathione reductase, and aldose reductase were increased, while superoxide dismutase activity was decreased. Treatment with Vit B6 reversed these effects. These results demonstrated that administration of Vit B6 is potentially beneficial agent to reduce the lens damage in VPA toxicity, probably by decreasing oxidative stress.
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Affiliation(s)
- S Tunali
- Department of Chemistry, Faculty of Engineering, Istanbul University, Istanbul, Turkey
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7
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Klaunig JE, Hocevar BA, Kamendulis LM. Mode of Action analysis of perfluorooctanoic acid (PFOA) tumorigenicity and Human Relevance. Reprod Toxicol 2011; 33:410-418. [PMID: 22120428 DOI: 10.1016/j.reprotox.2011.10.014] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 10/01/2011] [Accepted: 10/24/2011] [Indexed: 11/19/2022]
Abstract
Perfluorooctanoic acid (PFOA) is an environmentally persistent chemical used in the manufacturing of a wide array of industrial and commercial products. PFOA has been shown to induce tumors of the liver, testis and pancreas (tumor triad) in rats following chronic dietary administration. PFOA belongs to a group of compounds that are known to activate the PPARα receptor. The PPARα activation Mode of Action was initially addressed in 2003 [9] and further refined in subsequent reviews [92-94]. In the intervening time, additional information on PFOA effects as well as a further refinement of the Mode of Action framework warrants a re-examination of this compound for its cancer induction Mode of Action. This review will address the rodent (rat) cancer data and cancer Mode of Action of PFOA for tumors of the liver, testes and pancreas.
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Affiliation(s)
- James E Klaunig
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States.
| | - Barbara A Hocevar
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States
| | - Lisa M Kamendulis
- Indiana University, Department of Environmental Health, Bloomington, IN 47405, United States
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8
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Bednarkiewicz A, Rodrigues RM, Whelan MP. Non-invasive monitoring of cytotoxicity based on kinetic changes of cellular autofluorescence. Toxicol In Vitro 2011; 25:2088-94. [PMID: 21959354 DOI: 10.1016/j.tiv.2011.09.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 07/22/2011] [Accepted: 09/12/2011] [Indexed: 11/25/2022]
Abstract
A quantitative, non-destructive cellular autofluorescence based in vitro imaging assay has been developed and applied to study the cytotoxicity of Sodium Lauryl Sulfate (SLS) and HgCl2 on Balb/c 3T3 cells. A phenomenological double logistic model was proposed to quantify and relate the observed kinetic changes of fluorescence to the toxic potency of chemical compounds. This work forms the basis for cellular autofluorescence measurements in in vitro toxicity screening assays.
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Affiliation(s)
- Artur Bednarkiewicz
- Institute for Health and Customer Protection, European Commission Joint Research Centre, 21-027 Ispra (VA), Italy.
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9
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Deepa D, Jayakumari B, Thomas SV. Lipid peroxidation in women with epilepsy. Ann Indian Acad Neurol 2011; 11:44-6. [PMID: 19966978 PMCID: PMC2781145 DOI: 10.4103/0972-2327.40225] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 03/08/2008] [Accepted: 03/10/2008] [Indexed: 12/26/2022] Open
Abstract
Background: Lipid peroxidation is an indicator of free radical metabolism and oxidative stress in human beings and other organisms. Malondialdehyde (MDA), an end product of lipid peroxidation, is a metabolite that can be readily estimated in serum samples. Excess oxidative stress may be a final common pathway through which anti epileptic drugs may exert their teratogenic potential in pregnant women with epilepsy. Our objective in this study was to ascertain the variations in malondialdehyde (MDA) in women with epilepsy. Material and Methods: This study was carried out in the Kerala Registry of Epilepsy and pregnancy after obtaining clearance from the Institutional Ethics Committee. Informed consent was obtained from all the subjects. The quantitative examination of MDA was performed according to standard procedures. The ideal plasma level of MDA is below 2 nmol/ml. Results: Fifteen women with confirmed epilepsy (mean age 26.9 ± 3.5) were included in the study. Two women were pregnant. MDA levels ranged from 1.7 to 2.8 nmol/ml (mean level = 2.13 ± 0.37 nmol/ml). Eight women (53 %) had MDA levels above the upper limit of normal. Three patients had levels above 2.5 nmol/ml, which corresponded to the 75 centile. Conclusions: This study had shown that the estimation of MDA levels in plasma is a convenient method to study lipid peroxidation and thereby oxidative stress in women with epilepsy. Over half of Women With Epilepsy (WWE) have excess oxidative stress as indicated by high levels of MDA in the plasma. Correlations between MDA level and characteristics of epilepsy, AED therapy, nutritional status and other medical conditions need to be observed in a larger cohort.
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Affiliation(s)
- D Deepa
- Kerala Registry of Epilepsy and Pregnancy, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
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10
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Dykens JA, Will Y. Biomarkers of in Vitro Drug‐Induced Mitochondrial Dysfunction. Biomarkers 2010. [DOI: 10.1002/9780470918562.ch16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Shaw PJ, Ganey PE, Roth RA. Idiosyncratic drug-induced liver injury and the role of inflammatory stress with an emphasis on an animal model of trovafloxacin hepatotoxicity. Toxicol Sci 2010; 118:7-18. [PMID: 20538741 DOI: 10.1093/toxsci/kfq168] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Idiosyncratic adverse drug reactions (IADRs) occur in a minority of patients yet account for the majority of postmarketing use restrictions by the Food and Drug Administration. Despite the impact of these toxicities, the underlying mechanisms are still poorly understood. Animal models of IADRs would be beneficial in understanding mechanisms and in developing assays with predictive potential. Recent work exploring the interactions between inflammatory stress and drugs associated with human idiosyncratic drug-induced liver injury (IDILI) has led to the development of the first animal models that apply to a range of drugs. Here, we discuss hypotheses for the mechanisms of IDILI and focus on a murine model of trovafloxacin-induced hepatotoxicity as an example related to the inflammatory stress hypothesis.
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Affiliation(s)
- Patrick J Shaw
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, Tennessee 38104, USA
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Constantin D, Constantin-Teodosiu D, Layfield R, Tsintzas K, Bennett AJ, Greenhaff PL. PPARdelta agonism induces a change in fuel metabolism and activation of an atrophy programme, but does not impair mitochondrial function in rat skeletal muscle. J Physiol 2007; 583:381-90. [PMID: 17540700 PMCID: PMC2277240 DOI: 10.1113/jphysiol.2007.135459] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
PPARalpha agonism impairs mitochondrial function, but the effect of PPARdelta agonism on mitochondrial function is equivocal. Furthermore, PPARalpha and delta agonism increases muscle fatty acid oxidation, potentially via activation of FOXO1 signalling and PDK4 transcription. Since FOXO1 activation has also been suggested to increase transcription of MAFbx and MuRF-1, and thereby the activation of ubiquitin-proteasome mediated muscle proteolysis, this raises the possibility that muscle fuel selection and the induction of a muscle atrophy programme could be regulated by a single common signalling pathway. We therefore investigated the effect of PPARdelta (delta) agonist, GW610742, administration on muscle mitochondrial function, fuel regulation, and atrophy and growth related signalling pathways in vivo. Twenty-four male Wistar rats received vehicle or GW610742 (5 and 100 mg per kg body mass (bm)) orally for 6 days. Soleus muscle was used to determine maximal rates of ATP production (MRATP) in isolated mitochondria, gene and protein expression, and enzyme activities. MRATP were unchanged by GW610742. Muscle PDK2 and PDK4 mRNA expression increased with GW610742 (100 mg (kg bm)(-1)) compared to vehicle (P<0.05), and was paralleled by a twofold increase in PDK4 protein expression (P<0.05). The activity of beta-hydroxyacyl-CoA dehydrogenase increased with GW610742 (P<0.05). Muscle MuRF1 and MAFbx mRNA expression was increased by GW610742 (100 mg (kg bm)(-1)) compared to vehicle (P<0.05), and was matched by increased protein expression (P<0.001), whilst Akt1 protein declined (P<0.05). There was no effect of GW610742 on 20S proteasome activity and mRNA expression, or the muscle DNA: protein ratio. GW610742 switched muscle fuel metabolism towards decreased carbohydrate use and enhanced lipid utilization, but did not induce mitochondrial dysfunction. Furthermore, GW610742 initiated a muscle atrophy programme, possibly via changes in the Akt1/FOXO/MAFbx and MuRF1 signalling pathway.
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Affiliation(s)
- Despina Constantin
- Centre for Integrated Systems Biology and Medicine, Queens Medical Centre, University of Nottingham Medical School, Nottingham NG7 2UH, UK.
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Boelsterli UA, Lim PLK. Mitochondrial abnormalities--a link to idiosyncratic drug hepatotoxicity? Toxicol Appl Pharmacol 2006; 220:92-107. [PMID: 17275868 DOI: 10.1016/j.taap.2006.12.013] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2006] [Revised: 12/12/2006] [Accepted: 12/12/2006] [Indexed: 12/17/2022]
Abstract
Idiosyncratic drug-induced liver injury (DILI) is a major clinical problem and poses a considerable challenge for drug development as an increasing number of successfully launched drugs or new potential drugs have been implicated in causing DILI in susceptible patient subsets. Although the incidence for a particular drug is very low (yet grossly underestimated), the outcome of DILI can be serious. Unfortunately, prediction has remained poor (both for patients at risk and for new chemical entities). The underlying mechanisms and the determinants of susceptibility have largely remained ill-defined. The aim of this review is to provide both clinical and experimental evidence for a major role of mitochondria both as a target of drugs causing idiosyncratic DILI and as mediators of delayed liver injury. We develop a unifying hypothesis that involves underlying genetic or acquired mitochondrial abnormalities as a major determinant of susceptibility for a number of drugs that target mitochondria and cause DILI. The mitochondrial hypothesis, implying gradually accumulating and initially silent mitochondrial injury in heteroplasmic cells which reaches a critical threshold and abruptly triggers liver injury, is consistent with the findings that typically idiosyncratic DILI is delayed (by weeks or months), that increasing age and female gender are risk factors and that these drugs are targeted to the liver and clearly exhibit a mitochondrial hazard in vitro and in vivo. New animal models (e.g., the Sod2(+/-) mouse) provide supporting evidence for this concept. However, genetic analyses of DILI patient samples are needed to ultimately provide the proof-of-concept.
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Affiliation(s)
- Urs A Boelsterli
- Molecular Toxicology Lab, Department of Pharmacology, Yong Loo Lin School of Medicine, Singapore.
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14
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Rusyn I, Peters JM, Cunningham ML. Modes of action and species-specific effects of di-(2-ethylhexyl)phthalate in the liver. Crit Rev Toxicol 2006; 36:459-79. [PMID: 16954067 PMCID: PMC2614359 DOI: 10.1080/10408440600779065] [Citation(s) in RCA: 183] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The industrial plasticizer di-(2-ethylhexyl)phthalate (DEHP) is used in manufacturing of a wide variety of polyvinyl chloride (PVC)-containing medical and consumer products. DEHP belongs to a class of chemicals known as peroxisome proliferators (PPs). PPs are a structurally diverse group of compounds that share many (but perhaps not all) biological effects and are characterized as non-genotoxic rodent carcinogens. This review focuses on the effect of DEHP in liver, a primary target organ for the pleiotropic effects of DEHP and other PPs. Specifically, liver parenchymal cells, identified herein as hepatocytes, are a major cell type that are responsive to exposure to PPs, including DEHP; however, other cell types in the liver may also play a role. The PP-induced increase in the number and size of peroxisomes in hepatocytes, so called 'peroxisome proliferation' that results in elevation of fatty acid metabolism, is a hallmark response to these compounds in the liver. A link between peroxisome proliferation and tumor formation has been a predominant, albeit questioned, theory to explain the cause of a hepatocarcinogenic effect of PPs. Other molecular events, such as induction of cell proliferation, decreased apoptosis, oxidative DNA damage, and selective clonal expansion of the initiated cells have been also been proposed to be critically involved in PP-induced carcinogenesis in liver. Considerable differences in the metabolism and molecular changes induced by DEHP in the liver, most predominantly the activation of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)alpha, have been identified between species. Both sexes of rats and mice develop adenomas and carcinomas after prolonged feeding with DEHP; however, limited DEHP-specific human data are available, even though exposure to DEHP and other phthalates is common in the general population. This likely constitutes the largest gap in our knowledge on the potential for DEHP to cause liver cancer in humans. Overall, it is believed that the sequence of key events that are relevant to DEHP-induced liver carcinogenesis in rodents involves the following events whereby the combination of the molecular signals and multiple pathways, rather than a single hallmark event (such as induction of PPARalpha and peroxisomal genes, or cell proliferation) contribute to the formation of tumors: (i) rapid metabolism of the parental compound to primary and secondary bioactive metabolites that are readily absorbed and distributed throughout the body; (ii) receptor-independent activation of hepatic macrophages and production of oxidants; (iii) activation of PPARalpha in hepatocytes and sustained increase in expression of peroxisomal and non-peroxisomal metabolism-related genes; (iv) enlargement of many hepatocellular organelles (peroxisomes, mitochondria, etc.); (v) rapid but transient increase in cell proliferation, and a decrease in apoptosis; (vi) sustained hepatomegaly; (vii) chronic low-level oxidative stress and accumulation of DNA damage; (viii) selective clonal expansion of the initiated cells; (ix) appearance of the pre-neoplastic nodules; (x) development of adenomas and carcinomas.
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Affiliation(s)
- Ivan Rusyn
- Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina, Chapel Hill, 27599-7431, USA.
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15
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Abstract
Mitochondria play a critical role in generating most of the cell's energy as ATP. They are also involved in other metabolic processes such as urea generation, haem synthesis and fatty acid beta-oxidation. Disruption of mitochondrial function by drugs can result in cell death by necrosis or can signal cell death by apoptosis (e.g., following cytochrome c release). Drugs that injure mitochondria usually do so by inhibiting respiratory complexes of the electron chain; inhibiting or uncoupling oxidative phosphorylation; inducing mitochondrial oxidative stress; or inhibiting DNA replication, transcription or translation. It is important to test for mitochondrial toxicity early in drug development as impairment of mitochondrial function can induce various pathological conditions that are life threatening or can increase the progression of existing mitochondrial diseases.
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Affiliation(s)
- Katie Chan
- University of Toronto, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Toronto, Ontario, M5S 2S2, Canada
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16
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Natarajan SK, Eapen CE, Pullimood AB, Balasubramanian KA. Oxidative stress in experimental liver microvesicular steatosis: role of mitochondria and peroxisomes. J Gastroenterol Hepatol 2006; 21:1240-9. [PMID: 16872304 DOI: 10.1111/j.1440-1746.2006.04313.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Hepatic microvesicular steatosis is a clinical manifestation seen in a number of liver diseases. Although the role of mitochondrial beta-oxidation in the development of the disease has been well studied, information on lipid peroxidative damage in liver subcellular organelles is scarce. The present study looked at oxidative stress in hepatic peroxisomes and microsomes in microvesicular steatosis, using an animal model of the disease. METHODS Rats were given i.p. injections of sodium valproate (700 mg/kg bodyweight) to induce microvesicular steatosis, which was confirmed by histology. RESULTS Oxidative stress was evident in liver in steatosis, accompanied by structural and functional alterations in hepatic mitochondria. Alterations in lipid composition, with decreased phosphatidyl choline and ethanolamine and increased lysophosphatidyl choline and ethanolamine, were seen. An increase in triglyceride content was also seen. In addition, increased lipid peroxidation was also evident in peroxisomes and microsomes from steatotic rats. Pretreatment with clofibrate results in partial reversal of changes produced by valproate. CONCLUSIONS These results suggest that in addition to impaired mitochondrial beta-oxidation, oxidative stress is also seen in the hepatic peroxisomes and microsomes during microvesicular steatosis.
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Affiliation(s)
- Sathish Kumar Natarajan
- Wellcome Trust Research Laboratory, Department of Gastrointestinal Sciences, Christian Medical College, Vellore, India
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17
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Iwamoto K, Bundo M, Kato T. Altered expression of mitochondria-related genes in postmortem brains of patients with bipolar disorder or schizophrenia, as revealed by large-scale DNA microarray analysis. Hum Mol Genet 2004; 14:241-53. [PMID: 15563509 DOI: 10.1093/hmg/ddi022] [Citation(s) in RCA: 356] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Accumulating evidence suggests that mitochondrial dysfunction underlies the pathophysiology of bipolar disorder (BD) and schizophrenia (SZ). We performed large-scale DNA microarray analysis of postmortem brains of patients with BD or SZ, and examined expression patterns of mitochondria-related genes. We found a global down-regulation of mitochondrial genes, such as those encoding respiratory chain components, in BD and SZ samples, even after the effect of sample pH was controlled. However, this was likely due to the effects of medication. Medication-free patients with BD showed tendency of up-regulation of subset of mitochondrial genes. Our findings support the mitochondrial dysfunction hypothesis of BD and SZ pathologies. However, it may be the expression changes of a small fraction of mitochondrial genes rather than the global down-regulation of mitochondrial genes. Our findings warrant further study of the molecular mechanisms underlying mitochondrial dysfunction in BD and SZ.
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Affiliation(s)
- Kazuya Iwamoto
- Laboratory for Molecular Dynamics of Mental Disorders, Brain Science Institute, RIKEN, Wako, Saitama, Japan
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18
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Nulton-Persson AC, Szweda LI, Sadek HA. Inhibition of Cardiac Mitochondrial Respiration by Salicylic Acid and Acetylsalicylate. J Cardiovasc Pharmacol 2004; 44:591-5. [PMID: 15505497 DOI: 10.1097/00005344-200411000-00012] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Acetylsalicylate, the active ingredient in aspirin, has been shown to be beneficial in the treatment and prevention of cardiovascular disease. Because of the increasing frequency with which salicylates are used, it is important to more fully characterize extra- and intracellular processes that are altered by these compounds. Evidence is provided that treatment of isolated cardiac mitochondria with salicylic acid and to a lesser extent acetylsalicylate resulted in an increase in the rate of uncoupled respiration. In contrast, both compounds inhibited ADP-dependent NADH-linked (state 3) respiration to similar degrees. Under the conditions of our experiments, loss in state 3 respiration resulted from inhibition of the Krebs cycle enzyme alpha-ketoglutarate dehydrogenase (KGDH). Kinetic analysis indicates that salicylic acid acts as a competitive inhibitor at the alpha-ketoglutarate binding site. In contrast, acetylsalicylate inhibited the enzyme in a noncompetitive fashion consistent with interaction with the alpha-ketoglutarate binding site followed by enzyme-catalyzed acetylation. The effects of salicylic acid and acetylsalicylate on cardiac mitochondrial function may contribute to the known cardioprotective effects of therapeutic doses of aspirin, as well as to the toxicity associated with salicylate overdose.
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Affiliation(s)
- Amy C Nulton-Persson
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, USA
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19
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Brunmair B, Lest A, Staniek K, Gras F, Scharf N, Roden M, Nohl H, Waldhäusl W, Fürnsinn C. Fenofibrate Impairs Rat Mitochondrial Function by Inhibition of Respiratory Complex I. J Pharmacol Exp Ther 2004; 311:109-14. [PMID: 15166256 DOI: 10.1124/jpet.104.068312] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Fibrates are used for the treatment of dyslipidemia and known to affect mitochondrial function in vitro. To better understand the mechanisms underlying their mitochondrial effects, fibrate actions on complex I of the respiratory chain and cell respiration were studied in vitro. In homogenates of rat skeletal muscle, fenofibrate, and to a lesser extent clofibrate, reduced the activity of complex I (10, 30, and 100 microM fenofibrate: -41 +/- 7%, -70 +/- 2%, and -78 +/- 4%; 100 microM clofibrate: -27 +/- 7%; p < 0.005 each). Inhibition of complex I by fenofibrate (100 microM) was confirmed by reduced state 3 respiration of isolated mitochondria consuming glutamate + malate as substrates for complex I (-33 +/- 4%; p < 0.0005), but not of such consuming succinate as substrate for complex II (-8 +/- 4%; NS). In isolated rat muscle, 24-h fenofibrate exposure (25, 50, and 100 microM) decreased CO(2) production from palmitate (-15 +/- 7%, -23 +/- 8%, and -22 +/- 7%; p < 0.05 each) and increased lactate release (+15 +/- 5%, +14 +/- 5%, and + 17 +/- 6%; p < 0.02 each) indicating impaired cell respiration. Ciprofibrate and gemfibrocil (but not bezafibrate) impaired cell respiration without any inhibition of complex I. Our findings support the notion that individual fibrates induce mitochondrial dysfunction via different molecular mechanisms and show that fenofibrate predominantly acts by inhibition of complex I of the respiratory chain.
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Affiliation(s)
- Barbara Brunmair
- Department of Medicine III, Division of Endocrinology and Metabolism, Währinger Gürtel 18-20, A-1090 Vienna, Austria
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20
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Qu B, Li QT, Wong KP, Tan TM, Halliwell B. Mechanism of clofibrate hepatotoxicity: mitochondrial damage and oxidative stress in hepatocytes. Free Radic Biol Med 2001; 31:659-69. [PMID: 11522451 DOI: 10.1016/s0891-5849(01)00632-3] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Peroxisome proliferators have been found to induce hepatocarcinogenesis in rodents, and may cause mitochondrial damage. Consistent with this, clofibrate increased hepatic mitochondrial oxidative DNA and protein damage in mice. The present investigation aimed to study the mechanism by which this might occur by examining the effect of clofibrate on freshly isolated mouse liver mitochondria and a cultured hepatocyte cell line, AML-12. Mitochondrial membrane potential (Delta Psi(m)) was determined by using the fluorescent dye 5,5',6,6'-tetrachloro-1,1', 3,3'-tetraethyl-benzimidazolylcarbocyanine iodide (JC-1) and tetramethylrhodamine methyl ester (TMRM). Application of clofibrate at concentrations greater than 0.3 mM rapidly collapsed the Delta Psi(m) both in liver cells and in isolated mitochondria. The loss of Delta Psi(m) occurred prior to cell death and appeared to involve the mitochondrial permeability transition (MPT), as revealed by calcein fluorescence studies and the protective effect of cyclosporin A (CsA) on the decrease in Delta Psi(m). Levels of reactive oxygen species (ROS) were measured with the fluorescent probes 5-(and-6)-carboxy-2',7'-dichlorofluorescein diacetate (DCFDA) and dihydrorhodamine 123 (DHR123). Treatment of the hepatocytes with clofibrate caused a significant increase in intracellular and mitochondrial ROS. Antioxidants such as vitamin C, deferoxamine, and catalase were able to protect the cells against the clofibrate-induced loss of viability, as was CsA, but to a lesser extent. These results suggest that one action of clofibrate might be to impair mitochondrial function, so stimulating formation of ROS, which eventually contribute to cell death.
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Affiliation(s)
- B Qu
- Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore, Singapore
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21
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Yüksel A, Cengiz M, Seven M, Ulutin T. Changes in the antioxidant system in epileptic children receiving antiepileptic drugs: two-year prospective studies. J Child Neurol 2001; 16:603-6. [PMID: 11510935 DOI: 10.1177/088307380101600814] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to measure changes in the antioxidant systems of epileptic children who had been receiving either valproate or carbamazepine monotherapy for 2 years. For this purpose, levels of erythrocyte glutathione, glutathione peroxidase, superoxide dismutase, and serum lipid peroxidation in 25 healthy children and 27 children who had previously been diagnosed as having epilepsy but who had not, prior to the study, received antiepileptic drugs were tested. Of the 27 epileptic children, 14 were given valproate, and the remaining 13 were given carbamazepine; these tests were repeated in the 13th and 24th months of treatment. The results showed that, during valproate therapy, the lipid peroxidation levels of the epileptic children increased and the glutathione peroxidase levels decreased in comparison with those levels recorded in the control and pretreatment groups. In addition, the superoxide dismutase levels were found to be increased during the first year of valproate therapy when compared with those of the pretreatment group. However, during carbamazepine therapy, lipid peroxidation levels increased when compared with the control group only, not the pretreatment group. Furthermore, the results showed that during the second year of treatment, the superoxide dismutase levels of the children receiving carbamazapine monotherapy were found to be higher than those of both the control and pretreatment groups. From these results, it can be concluded that the antioxidant systems of the children who had been receiving valproate therapy during the 2 years were more significantly affected than those of the children who had been receiving carbamazepine.
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Affiliation(s)
- A Yüksel
- Cerrahpaşa Medical Faculty, Istanbul University, GETAM, Turkey.
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22
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Panaretakis T, Shabalina IG, Grandér D, Shoshan MC, DePierre JW. Reactive Oxygen Species and Mitochondria Mediate the Induction of Apoptosis in Human Hepatoma HepG2 Cells by the Rodent Peroxisome Proliferator and Hepatocarcinogen, Perfluorooctanoic Acid. Toxicol Appl Pharmacol 2001; 173:56-64. [PMID: 11350215 DOI: 10.1006/taap.2001.9159] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously shown that one of the most potent rodent hepatocarcinogens, perfluorooctanoic acid (PFOA), induces apoptosis in human HepG2 cells in a dose- and time-dependent manner. In this study we have investigated the involvement of reactive oxygen species (ROS), mitochondria, and caspase-9 in PFOA-induced apoptosis. Treatment with 200 and 400 microM PFOA was found to cause a dramatic increase in the cellular content of superoxide anions and hydrogen peroxide after 3 h. Measurement of the mitochondrial transmembrane potential (Delta Psi(m)) after PFOA treatment showed a dissipation of Delta Psi(m) at 3 h. Caspase-9 activation was seen at 5 h after treatment with 200 microM PFOA. In order to evaluate the importance of these events in PFOA-induced apoptosis, cells were cotreated with PFOA and N-acetylcysteine (NAC), a precursor of glutathione, or Cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition pore (MPT pore). NAC reduced Delta Psi(m) dissipation, caspase 9 activation, and apoptosis, indicating a role for PFOA-induced ROS. In addition, CsA also reduced Delta Psi(m) dissipation, caspase 9 activation, and apoptosis, indicating a role for PFOA-induced opening of the MPT pore. In summary, we have delineated a ROS and mitochondria-mediated pathway for induction of apoptosis by PFOA.
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Affiliation(s)
- T Panaretakis
- Unit of Biochemical Toxicology, Department of Biochemistry, Wallenberg Laboratory, Stockholm University, S-106 91 Stockholm, Sweden.
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23
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Yüksel A, Cengiz M, Seven M, Ulutin T. Erythrocyte glutathione, glutathione peroxidase, superoxide dismutase and serum lipid peroxidation in epileptic children with valproate and carbamazepine monotherapy. J Basic Clin Physiol Pharmacol 2000; 11:73-81. [PMID: 10851665 DOI: 10.1515/jbcpp.2000.11.1.73] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This prospective study was carried out to determine changes in the antioxidant system in epileptic children receiving long term antiepileptic drugs (AEDs). Levels of erythrocyte glutathione (GSH), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and serum lipid peroxidation were determined in 25 healthy children and 30 epileptic children who had not yet received AEDs. Sixteen patients were treated with valproic acid (VPA) and 14 with carbamazepine (CBZ); 13 months later these parameters were retested. The results showed that SOD and lipid peroxidation levels were increased but the GSH-Px levels were decreased in epileptic children on VPA therapy compared with the control group and the results before treatment. No significant differences of these parameters were found in epileptic children on CBZ therapy compared with the control group and the results before treatment, except that lipid peroxidation level was slightly higher in epileptic patients before treatment. We conclude that antioxidant systems in epileptic children on CBZ therapy are better regulated in comparison with epileptic children on VPA therapy.
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Affiliation(s)
- A Yüksel
- Cerrahpaşa Medical Faculty, Istanbul University, GETAM, Turkey.
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24
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Chevalier S, Macdonald N, Tonge R, Rayner S, Rowlinson R, Shaw J, Young J, Davison M, Roberts RA. Proteomic analysis of differential protein expression in primary hepatocytes induced by EGF, tumour necrosis factor alpha or the peroxisome proliferator nafenopin. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:4624-34. [PMID: 10903494 DOI: 10.1046/j.1432-1327.2000.01487.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Peroxisome proliferators are nongenotoxic rodent-liver carcinogens that have been shown to cause both an induction of hepatocyte proliferation and a suppression of apoptosis. Both epidermal growth factor (EGF) and the peroxisome proliferator nafenopin induce DNA replication in primary rat hepatocyte cultures, but apparently through different signalling pathways. However, both EGF and nafenopin require tumour necrosis factor alpha (TNFalpha) signalling to induce DNA replication. By examining proteins isolated from rat primary hepatocyte cultures using two-dimensional gel electrophoresis and mass spectrometry, we found that proteins showing an altered expression pattern in response to nafenopin differed from those showing altered expression in response to EGF. However, many proteins showing altered expression upon stimulation with TNFalpha were common to both the EGF and nafenopin responses. These proteome profiling experiments contribute to a better understanding of the molecular mechanisms involved in the response to peroxisome proliferators. We found 32 proteins with altered expression upon stimulation with nafenopin, including muscarinic acetylcholine receptor 3, intermediate filament vimentin and the beta subunit of the ATP synthase. These nonperoxisomal protein targets offer insights into the mechanisms of peroxisome proliferator-induced carcinogenesis in rodents and provide opportunities to identify toxicological markers to facilitate early identification of nongenotoxic carcinogens.
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Affiliation(s)
- S Chevalier
- Cancer Biology group, Zeneca Central Toxicology Laboratory, Macclesfield, UK.
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25
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Cengiz M, Yüksel A, Seven M. The effects of carbamazepine and valproic acid on the erythrocyte glutathione, glutathione peroxidase, superoxide dismutase and serum lipid peroxidation in epileptic children. Pharmacol Res 2000; 41:423-5. [PMID: 10704266 DOI: 10.1006/phrs.1999.0603] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Some epileptic drugs may change antioxidant enzyme activities in humans and experimental animals. Recent studies suggest that membrane lipid peroxidation may be causally involved in some forms of epilepsy, and the differences are reported in free radical scavenging enzyme levels. GSHpX, SOD, GSH are important parameters of antioxidant defence mechanisms. This study was undertaken to evaluate the effects of valproic acid and carbamazepine (CBZ) therapy on erythrocyte glutathione (GSH), glutathione peroxidase (GSHpX), superoxide dismutase (SOD) and lipid peroxidation. During the treatment with VPA or CBZ, the erythrocyte GSHpX and GSH levels of epileptic children were significantly changed as compared to those of health control subjects. The mean levels of serum lipid peroxidation and erythrocyte superoxide dismutase were not statistically different from controls. The methods used for investigation of glutathione peroxidase, superoxide dismutase, glutathione and serum lipid peroxidation were all based on spectrophotometric measurement.
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Affiliation(s)
- M Cengiz
- Department of Medical and Biological Sciences, Cerrahpasa Medical Faculty, Istanbul University Cerrahpasa, Istanbul, Turkey
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26
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Qu B, Li QT, Wong KP, Ong CN, Halliwell B. Mitochondrial damage by the "pro-oxidant" peroxisomal proliferator clofibrate. Free Radic Biol Med 1999; 27:1095-102. [PMID: 10569642 DOI: 10.1016/s0891-5849(99)00143-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Clofibrate is a peroxisome proliferator that can cause hepatic cancer in rodents. It has been suggested that oxidative damage is involved in this hepatocarcinogenesis, although the data are conflicting. We confirmed that clofibrate causes oxidative damage in nuclei from the livers of mice treated with this substance, measured both as protein carbonyls and levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA. In addition, clofibrate also affects mitochondria, causing elevated levels of carbonyls and 8-OHdG, increased state 4 respiration and decreased adenosine triphosphatase (ATPase) activity. No evidence for clofibrate-induced lipid peroxidation in mitochondria was obtained. We propose that mitochondria may be a major target of injury and a source of oxidative stress in clofibrate-treated animals.
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Affiliation(s)
- B Qu
- Department of Biochemistry, National University of Singapore, Singapore
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27
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Youssef J, Badr M. Extraperoxisomal targets of peroxisome proliferators: mitochondrial, microsomal, and cytosolic effects. Implications for health and disease. Crit Rev Toxicol 1998; 28:1-33. [PMID: 9493760 DOI: 10.1080/10408449891344182] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Peroxisome proliferators are a structurally diverse group of compounds that include the fibrate hypolipidemic drugs, the phthalate ester industrial plasticizers, the phenoxy acid herbicides, and the anti-wetting corrosion inhibitors perfluorinated straight-chain monocarboxylic fatty acids. Administration of these chemicals to rodents results in a number of effects, the most prominent being hepatomegaly and induction of peroxisomal enzyme activities. Several of these compounds have also been associated with the production of liver tumors in rodents and are classified as nongenotoxic hepatocarcinogens. Experimental evidence suggests that humans are not susceptible to these effects following exposure to peroxisome-proliferating compounds. This has led to the proposal that an "actual threat to humans" from exposure to one of these compounds seems "rather unlikely". Indeed, recent reports suggest that peroxisome proliferators may prove valuable as antitumor agents in humans. However, this assessment is preliminary given that peroxisome proliferators also produce a myriad of extraperoxisomal effects in livers and other tissues of experimental animals. Such effects include both stimulation and inhibition of mitochondrial and microsomal metabolism and alteration of the activities of various cytosolic enzymes. These responses may be directly or indirectly related to the effects on peroxisomes or may be totally independent of these events. Whether the extraperoxisomal effects of these compounds occur in humans is not known and their potential impact on human health remains to be investigated.
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Affiliation(s)
- J Youssef
- University of Missouri-Kansas City, 64108-2792, USA
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Chance DS, McIntosh MK. Hypolipidemic agents alter hepatic mitochondrial respiration in vitro. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1995; 111:317-23. [PMID: 8521251 DOI: 10.1016/0742-8413(95)00056-t] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The direct effects of three different classes of structurally diverse hypolipidemic agents on respiration were studied in mitochondria isolated from donor Sprague-Dawley rats. Two classes of peroxisome proliferators (i.e. plasticizers and hypolipidemic hormones and drugs) and one class of peroxisome inhibitors (i.e. anti-psychotic drugs) were studied. The phthalate ester plasticizers dibutylphthalate, ethylhexanoic acid and di(2-ethylhexyl) adipate, the hypolipidemic hormones or drugs dehydro-epiandrosterone (DHEA), thyroxine (T4), triiodothyronine (T3), gemfibrozil, clofibrate and naphthoflavone, and the anti-psychotic drugs chlorpromazine, thioridazine and fluphenazine were studied. As the dose of the plasticizer dibutylphthalate increased from 8 to 200 mumol/l, there was a decrease (P < 0.05) in state 3 (+ADP) respiration and in the respiratory control ratio for both substrates tested. The anti-psychotic drug chlorpromazine decreased state 3 malate + pyruvate-supported respiration and increased state 3 succinate-supported respiration. As the concentration of all three anti-psychotic drugs increased, there was a linear increase in state 4 respiration (-ADP) and a decrease in the respiratory control ratio for both substrates tested. As the dose of the hypolipidemic agents DHEA, gemfibrozil and T4 increased, there was a linear reduction in state 3 malate + pyruvate-supported respiration. However, when succinate was used as the substrate to support respiration, only the thyroid hormones significantly decreased state 3 respiration. Gemfibrozil, T4 and T3 increased state 4 respiration, regardless of the substrate used. As the dose of clofibrate, gemfibrozil, and the thyroid hormones increased, there was a linear reduction in the respiratory control ratio for both substrates tested.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D S Chance
- Department of Food, Nutrition, and Food Service Management, University of North Carolina at Greensboro 27412, USA
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29
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Abstract
Studies show that peroxisome proliferators inhibit mitochondrial beta-oxidation of fatty acids. However, mechanism(s) of this inhibitory effect has not been identified. This study was undertaken to delineate such mechanism(s). Ketogenesis was significantly diminished in perfused livers from rats pre-treated with diethylhexyl phthalate (DEHP) compared with livers from control rats. Monethylhexyl phthalate (MEHP; 200 microM), a primary metabolite of DEHP and a known peroxisome proliferator, inhibited the oxidation of palmitic acid as well as its acyl-CoA and acylcarnitine derivatives in isolated mitochondria by about 50-60%. Similar concentrations of MEHP also inhibited mitochondrial respiration of succinate and malate plus glutamate. However, respiration of ascorbate was not influenced by MEHP. Considering the assembly of the mitochondrial respiratory chain, these data indicate that phthalates inhibit fatty acid metabolism as a result of inhibiting the respiratory chain at the level of the cytochrome c reductase. This effect may represent an early step in the mechanism by which phthalates cause hepatic peroxisome proliferation.
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Affiliation(s)
- L D Winberg
- Division of Pharmacology, University of Missouri-Kansas City 64108-2792
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