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Hartman JH, Miller GP, Meyer JN. Toxicological Implications of Mitochondrial Localization of CYP2E1. Toxicol Res (Camb) 2017; 6:273-289. [PMID: 28989700 DOI: 10.1039/c7tx00020k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cytochrome P450 2E1 (CYP2E1) metabolizes an extensive array of pollutants, drugs, and other small molecules, often resulting in bioactivation to reactive metabolites. Therefore, it is unsurprising that it has been the subject of decades of research publications and reviews. However, while CYP2E1 has historically been studied in the endoplasmic reticulum (erCYP2E1), active CYP2E1 is also present in mitochondria (mtCYP2E1). Relatively few studies have specifically focused on mtCYP2E1, but there is growing interest in this form of the enzyme as a driver in toxicological mechanisms given its activity and location. Many previous studies have linked total CYP2E1 to conditions that involve mitochondrial dysfunction (fasting, diabetes, non-alcoholic steatohepatitis, and obesity). Furthermore, a large number of reactive metabolites that are formed by CYP2E1 through metabolism of drugs and pollutants have been demonstrated to cause mitochondrial dysfunction. Finally, there appears to be significant inter-individual variability in targeting to the mitochondria, which could constitute a source of variability in individual response to exposures. This review discusses those outcomes, the biochemical properties and toxicological consequences of mtCYP2E1, and highlights important knowledge gaps and future directions. Overall, we feel that this exciting area of research is rich with new and important questions about the relationship between mtCYP2E1, mitochondrial dysfunction, and pathology.
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Affiliation(s)
| | - Grover P Miller
- Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR
| | - Joel N Meyer
- Nicholas School of the Environment, Duke University, Durham, NC
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Chao CT, Chiang CK. Uremic toxins, oxidative stress, and renal fibrosis: an interwined complex. J Ren Nutr 2014; 25:155-9. [PMID: 25511523 DOI: 10.1053/j.jrn.2014.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 10/29/2014] [Indexed: 11/11/2022] Open
Abstract
The prevalence of end-stage renal diseases is currently on the rise globally, and finding the way to curb this tide is urgently needed. Tubulointerstitial fibrosis is a common pathway for essentially all the nephropathy categories known to date, and the manifestations of renal fibrosis include excessive deposition of extracellular matrix with distortion of renal microstructures and functional deterioration. Uremic toxins have been gradually found to play an important role in the development of progressive renal fibrosis, with protein-bound indoxyl sulfate, p-cresol, and p-cresyl sulfate receiving the most attention. However, the contribution of oxidative stress among the pathogenesis of uremic toxins and renal fibrosis has not been evaluated much until recently. In this review, we will discuss about the nature and sources of oxidative stress in the kidney and how uremic toxins use oxidative stress to orchestrate the processes of renal fibrosis.
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Affiliation(s)
- Chia-Ter Chao
- Renal Division, Department of Internal Medicine, National Taiwan University Hospital Jin-Shan Branch, New Taipei City, Taiwan; Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Graduate Institute of Toxicology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chih-Kang Chiang
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Graduate Institute of Toxicology, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Integrative Diagnostics and Therapeutics, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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Shayakhmetova GM, Bondarenko LB, Matvienko AV, Kovalenko VM. Correlation between spermatogenesis disorders and rat testes CYP2E1 mRNA contents under experimental alcoholism or type I diabetes. Adv Med Sci 2014; 59:183-9. [PMID: 25323755 DOI: 10.1016/j.advms.2014.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 03/10/2014] [Indexed: 01/23/2023]
Abstract
PURPOSE The aim of the study was to investigate the correlation between spermatogenesis disorders and CYP2E1 mRNA contents in testes of rats with experimental alcoholism or type I diabetes. MATERIAL/METHODS Two pathological states characterized by CYP2E1 induction were simulated on Wistar male rats: experimental alcoholism and type I diabetes. As controls for each state, equal number of animals (of the same age and weight) were used. Morphological evaluation of rat testes was carried out. The spermatogenic epithelium state was estimated by four points system. CYP2E1 mRNA expression was rated by method of reverse transcriptase polymerase chain reaction. Pearson correlation coefficients were used for describing relationships between variables. RESULTS The presence of alcoholism and diabetes-mediated quantitative and qualitative changes in male rat spermatogenic epithelium in comparison with norm has been demonstrated. The increased levels of testes CYP2E1 have been fixed simultaneously. CYP2E1 mRNA content negatively strongly correlated with spermatogenic index value (r=-0.99; P<0.001) and positively strongly correlated with epithelium desquamation occurrence (r=0.99; P<0.001) in testes of rats with chronic alcoholism. The strong correlation between CYP2E1 mRNA content and number of spermatogonia (r=0.99; P<0.001) and "windows" occurrence (r=0.96; P<0.001) has been fixed in diabetic rats testes. CONCLUSIONS Present investigation has demonstrated that the testicular failure following chronic ethanol consumption and diabetes type I in male rats accompanied CYP2E1 mRNA over-expression in testes. The correlation between the levels of CYP2E1 mRNA in testes and spermatogenesis disorders allow supposing the involvement of CYP2E1 into the non-specific pathogenetic mechanisms of male infertility under above-mentioned pathologies.
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Affiliation(s)
- Ganna M Shayakhmetova
- General Toxicology Department, SI "Institute of Pharmacology & Toxicology", National Academy of Medical Sciences of Ukraine, Kyiv, Ukraine.
| | - Larysa B Bondarenko
- General Toxicology Department, SI "Institute of Pharmacology & Toxicology", National Academy of Medical Sciences of Ukraine, Kyiv, Ukraine
| | - Anatoliy V Matvienko
- General Toxicology Department, SI "Institute of Pharmacology & Toxicology", National Academy of Medical Sciences of Ukraine, Kyiv, Ukraine
| | - Valentina M Kovalenko
- General Toxicology Department, SI "Institute of Pharmacology & Toxicology", National Academy of Medical Sciences of Ukraine, Kyiv, Ukraine
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Pyrrolidine dithiocarbamate (PDTC) blocks apoptosis and promotes ionizing radiation-induced necrosis of freshly-isolated normal mouse spleen cells. Apoptosis 2010; 15:705-14. [PMID: 20333468 DOI: 10.1007/s10495-010-0487-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Ionizing radiation (IR) is a pro-oxidant that kills cells by both apoptotic and necrotic mechanisms. Pyrrolidine dithiocarbamate (PDTC) is a thiol-containing compound that may act either as a pro- or anti-oxidant depending on the experimental conditions. This study was designed to determine whether PDTC would reduce or enhance IR-induced cell death of freshly-isolated normal mouse B6/129 spleen cells (NMSC). We determined the effect of increasing doses of IR, PDTC alone and PDTC followed by IR on the viability of NMSC. Annexin V and propidium iodide (Annexin V/PI) staining demonstrated a dose and time-dependent relationship in which PDTC enhanced the percentage of IR-induced apoptotic/necrotic NMSC. Trypan blue dye inclusion confirmed that a loss of membrane integrity was occurring 1 h after incubation with PDTC plus IR. Reduction in the glutathione (GSH)/glutathione disulfide (GSSG) ratio and GSH demonstrated that both IR (8.5 Gy) and PDTC acted as pro-oxidants, but their mechanisms of action differed: In contrast to IR, which promoted p53 activation and caspase 3/7-mediated apoptosis, PDTC inhibited IR-induced p53 and caspase 3/7 activity. However, PDTC increased H(2)O(2) formation and necrosis, resulting in an overall increase in IR-induced cell death. Catalase prevented the PDTC-induced increase in IR cytotoxicity implicating the generation of H(2)O(2) as a major factor in this mechanism. These results demonstrate that in NMSC PDTC acts as pro-oxidant and enhances IR-induced cell cytotoxicity by increasing H(2)O(2)formation and thiol oxidation. As such, they strongly suggest that the use of PDTC as an adjunct to reduce radiation toxicity should be avoided.
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Hubich AI, Lakhvich FA, Sholukh MV. The mechanism of the rat liver cytochrome P4502E1 inhibition by the synthetic prostanoids of A-type. Prostaglandins Other Lipid Mediat 2009; 89:16-9. [PMID: 19464662 DOI: 10.1016/j.prostaglandins.2009.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 01/27/2009] [Accepted: 02/20/2009] [Indexed: 11/19/2022]
Abstract
AIM The elucidation of mechanism of A-type synthetic prostanoids inhibitory action on microsomal cytochrome P(450)2E1 (CYP2E1) from rat liver activity was carried out. RESULTS Analogs U-34 and U-26 in a final concentration of 1 x 10(-5)M inhibited CYP2E1 activity by 93% and 46%, respectively; however natural prostaglandins had no effect. These synthetic prostanoids of A-type (5 x 10(-8) to 10(-4)M) inhibited chlorzoxazone hydroxylation in a dose-dependent manner while IC(50)=7.1 x 10(-7)M and 8.0 x 10(-7)M for U-26 and U-34, respectively. The curves of CYP2E1 activity in the presence of different concentrations of chlorzoxazone and varying concentration of prostanoids were hyperbolic. Double-reciprocal plots of these results 1/V=f(1/S) indicated that prostanoids inhibit CYP2E1 through a competitive mechanism with particular effect. CONCLUSION CYP2E1 is a target for A-type prostanoids, possessing 2-oxo-4-amino-oct-3(E)-enyl in alpha- or omega-chain, which are able to inhibit its action through a competitive mechanism.
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Affiliation(s)
- A I Hubich
- Department of Biochemistry, Belarussian State University, Minsk, Belarus.
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Abstract
Loss of redox homeostasis and formation of excessive free radicals play an important role in the pathogenesis of kidney disease and hypertension. Free radicals such as reactive oxygen species (ROS) are necessary in physiologic processes. However, loss of redox homeostasis contributes to proinflammatory and profibrotic pathways in the kidney, which in turn lead to reduced vascular compliance and proteinuria. The kidney is susceptible to the influence of various extracellular and intracellular cues, including the renin-angiotensin-aldosterone system (RAAS), hyperglycemia, lipid peroxidation, inflammatory cytokines, and growth factors. Redox control of kidney function is a dynamic process with reversible pro- and anti-free radical processes. The imbalance of redox homeostasis within the kidney is integral in hypertension and the progression of kidney disease. An emerging paradigm exists for renal redox contribution to hypertension.
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Affiliation(s)
- Ravi Nistala
- University of Missouri-Columbia School of Medicine, Department of Internal Medicine, Columbia, Missouri 65212, USA.
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Renal cell apoptosis induced by nephrotoxic drugs: cellular and molecular mechanisms and potential approaches to modulation. Apoptosis 2008; 13:11-32. [PMID: 17968659 DOI: 10.1007/s10495-007-0151-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Apoptosis plays a central role not only in the physiological processes of kidney growth and remodeling, but also in various human renal diseases and drug-induced nephrotoxicity. We present in a synthetic fashion the main molecular and cellular pathways leading to drug-induced apoptosis in kidney and the mechanisms regulating it. We illustrate them using three main nephrotoxic drugs (cisplatin, gentamicin, and cyclosporine A). We discuss the main regulators and effectors that have emerged as key targets for the design of therapeutic strategies. Novel approaches using gene therapy, antisense strategies, recombinant proteins, or compounds obtained from both classical organic and combinatorial chemistry are examined. Finally, key issues that need to be addressed for the success of apoptosis-based therapies are underlined.
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Lee YS, Wan J, Kim BJ, Bae MA, Song BJ. Ubiquitin-dependent degradation of p53 protein despite phosphorylation at its N terminus by acetaminophen. J Pharmacol Exp Ther 2005; 317:202-8. [PMID: 16330492 PMCID: PMC1409809 DOI: 10.1124/jpet.105.096719] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously reported that acetaminophen (APAP, 4-hydroxyacetanilide) caused apoptosis of C6 glioma cells. Therefore, we hypothesized that the level of p53, which usually stimulates apoptosis, might be increased after APAP exposure. However, APAP exposure for 24 h markedly decreased the p53 content and its downstream target p21 in a concentration-dependent manner. Reduction of p53 was not accompanied by a decrease in p53 mRNA in C6 glioma cells, suggesting that p53 was mainly affected at the protein level. Unexpectedly, APAP stimulated phosphorylation of p53 at Ser15, Ser20, and Ser37, which usually elevates p53 content. However, phosphorylation of these residues did not prevent APAP-induced decrease in p53. The p53 reduction was independent from the level of phospho-Akt, which is known to promote p53 degradation. Immunoblot analysis of the immunoprecipitated p53 revealed that increased amounts of murine double minute 2 (mdm2) and ubiquitin were bound to p53 during its degradation. Lactacystin and N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal (MG132), inhibitors of proteasomal proteolysis, prevented the decrease, supporting the proteasomal degradation of p53 upon APAP exposure. Pretreatment with chlormethiazole, an inhibitor of ethanol-inducible CYP2E1, significantly lowered the CYP2E1 enzyme activity and the rate of APAP-induced cell death while it prevented the reduction of p53 and p21 in C6 glioma cells. A nontoxic analog of APAP, 3-hydroxyacetanilde, did not reduce p53 and p21 contents in C6 glioma cells and LLC-PK1 porcine kidney cells. Taken together, our results show that APAP or its reactive metabolite(s) can directly reduce the p53 content through mdm2-mediated ubiquitin conjugation, despite phosphorylation of p53 at its N terminus.
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Affiliation(s)
| | | | | | | | - Byoung J. Song
- Corresponding author: Dr. B. J. Song, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, 9000 Rockville Pike, Bethesda, Maryland, USA. (Phone) 301-496-3985; (FAX) 301-594-3113; (e-mail)
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