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Sahoo DK, Chainy GBN. Hormone-linked redox status and its modulation by antioxidants. VITAMINS AND HORMONES 2023; 121:197-246. [PMID: 36707135 DOI: 10.1016/bs.vh.2022.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Hormones have been considered as key factors involved in the maintenance of the redox status of the body. We are making considerable progress in understanding interactions between the endocrine system, redox status, and oxidative stress with the dynamics of life, which encompasses fertilization, development, growth, aging, and various pathophysiological states. One of the reasons for changes in redox states of vertebrates leading to oxidative stress scenario is the disruption of the endocrine system. Comprehending the dynamics of hormonal status to redox state and oxidative stress in living systems is challenging. It is more difficult to come to a unifying conclusion when some hormones exhibit oxidant properties while others have antioxidant features. There is a very limited approach to correlate alteration in titers of hormones with redox status and oxidative stress with growth, development, aging, and pathophysiological stress. The situation is further complicated when considering various tissues and sexes in vertebrates. This chapter discusses the beneficial impacts of hormones with antioxidative properties, such as melatonin, glucagon, insulin, estrogens, and progesterone, which protect cells from oxidative damage and reduce pathophysiological effects. Additionally, we discuss the protective effects of antioxidants like vitamins A, E, and C, curcumin, tempol, N-acetyl cysteine, α-lipoic acid, date palm pollen extract, resveratrol, and flavonoids on oxidative stress triggered by hormones such as aldosterone, glucocorticoids, thyroid hormones, and catecholamines. Inflammation, pathophysiology, and the aging process can all be controlled by understanding how antioxidants and hormones operate together to maintain cellular redox status. Identifying the hormonal changes and the action of antioxidants may help in developing new therapeutic strategies for hormonal imbalance-related disorders.
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Affiliation(s)
- Dipak Kumar Sahoo
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Iowa States University, Ames, IA, United States.
| | - Gagan B N Chainy
- Department of Biotechnology, Utkal University, Bhubaneswar, Odisha, India
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Oliveri LM, Buzaleh AM, Gerez EN. An increase in O-GlcNAcylation of Sp1 down-regulates the gene expression of pi class glutathione S-transferase in diabetic mice. Biochem Biophys Rep 2021; 27:101049. [PMID: 34195388 PMCID: PMC8220555 DOI: 10.1016/j.bbrep.2021.101049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 04/28/2021] [Accepted: 06/07/2021] [Indexed: 12/19/2022] Open
Abstract
Oxidative stress is a key factor contributing to the development of diabetes complications. Glutathione S-transferases (GSTs) protect against products of oxidative stress by conjugating glutathione to electrophilic substrates, producing compounds that are generally less reactive and more soluble. The expression and activity of GSTs during diabetes have been extensively studied, but little is known about regulation mechanisms of Pi-class GST (GSTP). The aim of the present study was to evaluate how GSTP is regulated in a Streptozotocin (STZ)-induced murine diabetes model. GST activity and GSTP expression were determined in adult male mice diabetized with STZ. Specificity protein 1 (Sp1) expression and O-glycosylation, as well as the role of AP-1 members Jun and Fos in the regulation of GSTP expression, were also assessed. The results showed that GST total activity and GSTP mRNA and protein levels were decreased in the diabetic liver, and returned to normal values after insulin administration. The insulin-mimetic drug vanadate was also able to restore GST activity, but failed to recover GSTP mRNA/protein levels. In diabetic animals, O-glycosylated Sp1 levels were increased, whereas, in insulin-treated animals, glycosylation values were similar to those of controls. After vanadate administration, Sp1 expression levels and glycosylation were lower than those of controls. Our results suggest that hyperglycemia could lead to the observed increase in Sp1 O-glycosylation, which would, in turn, lead to a decrease in the expression of Sp1-dependent GSTP in the liver of diabetic mice.
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Affiliation(s)
- Leda María Oliveri
- Centro de Investigaciones Sobre Porfirinas y Porfirias (CIPYP), UBA-CONICET, Hospital de Clínicas José de San Martín, Universidad de, Buenos Aires, Argentina
| | - Ana María Buzaleh
- Centro de Investigaciones Sobre Porfirinas y Porfirias (CIPYP), UBA-CONICET, Hospital de Clínicas José de San Martín, Universidad de, Buenos Aires, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de, Buenos Aires, Argentina
| | - Esther Noemí Gerez
- Centro de Investigaciones Sobre Porfirinas y Porfirias (CIPYP), UBA-CONICET, Hospital de Clínicas José de San Martín, Universidad de, Buenos Aires, Argentina
- Cátedra Bioquímica General Celular y Molecular, Facultad de Ciencias Médicas, Universidad Católica Argentina (UCA), Buenos Aires, Argentina
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Abstract
In aerobes, oxygen is essential for maintenance of life. However, incomplete reduction of oxygen leads to generation of reactive oxygen species. These oxidants oxidise biological macromolecules present in their vicinity and thereby impair cellular functions causing oxidative stress (OS). Aerobes have evolved both enzymatic and nonenzymatic antioxidant defences to protect themselves from OS. Although hormones as means of biological coordination involve in regulation of physiological activities of tissues by regulating metabolism, any change in their normal titre leads to pathophysiological states. While, hormones such as melatonin, insulin, oestrogen, progesterone display antioxidant features, thyroid hormone, corticosteroids and catecholamines elicit free radical generation and OS, and the role of testosterone in inducing OS is debateable. This review is an attempt to understand the impact of free radical generation and cross talk between the hormones modulating antioxidant defence system under various pathophysiological conditions.
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Affiliation(s)
- Gagan B N Chainy
- Department of Biotechnology, Utkal University, Bhubaneswar, India
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Characterization and Validation of an "Acute Aerobic Exercise Load" as a Tool to Assess Antioxidative and Anti-inflammatory Nutrition in Healthy Subjects Using a Statistically Integrated Approach in a Comprehensive Clinical Trial. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9526725. [PMID: 31612079 PMCID: PMC6755301 DOI: 10.1155/2019/9526725] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 06/09/2019] [Indexed: 11/17/2022]
Abstract
The homeostatic challenge may provide unique opportunities for quantitative assessment of the health-promoting effects of nutritional interventions in healthy individuals. Objective. The present study is aimed at characterizing and validating the use of acute aerobic exercise (AAE) on a treadmill at 60% of VO2max for 30 min, in assessing the antioxidative and anti-inflammatory effects of a nutritional intervention. In a controlled, randomized, parallel trial of Korean black raspberry (KBR) (n = 24/group), fasting blood and urine samples collected before and following the AAE load at either baseline or 4-week follow-up were analyzed for biochemical markers, 1H-NMR metabolomics, and transcriptomics. The AAE was characterized using the placebo data only, and either the placebo or the treatment data were used in the validation. The AAE load generated a total of 50 correlations of 44 selected markers, based on Pearson's correlation coefficient analysis of 105 differential markers. Subsequent mapping of selected markers onto the KEGG pathway dataset showed 127 pathways relevant to the AAE load. Of these, 54 pathways involving 18 key targets were annotated to be related to oxidative stress and inflammation. The biochemical responses were amplified with the AAE load as compared to those with no load, whereas, the metabolomic and transcriptomic responses were downgraded. Furthermore, target-pathway network analysis revealed that the AAE load provided more explanations on how KBR exerted antioxidant effects in healthy subjects (29 pathways involving 12 key targets with AAE vs. 12 pathways involving 2 key targets without AAE). This study provides considerable insight into the molecular changes incurred by AAE and furthers our understanding that AAE-induced homeostatic perturbation could magnify oxidative and inflammatory responses, thereby providing a unique opportunity to test functional foods for antioxidant and anti-inflammatory purposes in clinical settings with healthy subjects.
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Hepatic expression of cytochrome P450 in Zucker diabetic fatty rats. Food Chem Toxicol 2016; 96:244-53. [DOI: 10.1016/j.fct.2016.08.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/02/2016] [Accepted: 08/05/2016] [Indexed: 11/21/2022]
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Xiao Y, Liu J, Peng Y, Xiong X, Huang L, Yang H, Zhang J, Tao L. GSTA3 Attenuates Renal Interstitial Fibrosis by Inhibiting TGF-Beta-Induced Tubular Epithelial-Mesenchymal Transition and Fibronectin Expression. PLoS One 2016; 11:e0160855. [PMID: 27602565 PMCID: PMC5014405 DOI: 10.1371/journal.pone.0160855] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/26/2016] [Indexed: 01/22/2023] Open
Abstract
Tubular epithelial-mesenchymal transition (EMT) has been widely accepted as the underlying mechanisms of renal interstitial fibrosis (RIF). The production of reactive oxygen species (ROS) plays a vital role in tubular EMT process. The purpose of this study was to investigate the involved molecular mechanisms in TGF-beta-induced EMT and identify the potential role of glutathione S-transferase alpha 3 (GSTA3) in this process. The iTRAQ screening was performed to identify protein alterations of the rats underwent unilateral-ureteral obstruction (UUO). Protein expression of GSTA3 in patients with obstructive nephropathy and UUO rats was detected by immunohistochemistry. Protein and mRNA expression of GSTA3 in UUO rats and NRK-52E cells were determined by Western blot and RT-PCR. siRNA and overexpression plasmid were transfected specifically to assess the role of GSTA3 in RIF. The generation of ROS was measured by dichlorofluorescein fluorescence analysis. GSTA3 protein and mRNA expression was significantly reduced in UUO rats. Immunohistochemical analysis revealed that GSTA3 expression was reduced in renal cortex in UUO rats and patients with obstructive nephropathy. Treating with TGF-β1 down-regulated GSTA3 expression in NRK-52E cells, which have been found to be correlated with the decreased expression in E-cadherin and megalin and increased expression in α-smooth muscle actin. Furthermore, knocking down GSTA3 in NRK-52 cells led to increased production of ROS and tubular EMT, whereas overexpressing GSTA3 ameliorated ROS production and prevented the occurrence of tubular EMT. GSTA3 plays a protective role against tubular EMT in renal fibrosis, suggesting GSTA3 is a potential therapeutic target for RIF.
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Affiliation(s)
- Yun Xiao
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078.,Division of Nephrology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China, 510120
| | - Jishi Liu
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078
| | - Yu Peng
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078
| | - Xuan Xiong
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078
| | - Ling Huang
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078
| | - Huixiang Yang
- Division of Digestive Medicine, Xiangya Hospital, Central South University, Changsha, China, 410078
| | - Jian Zhang
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
| | - Lijian Tao
- Division of Nephrology, Xiangya Hospital, Central South University, Changsha, China, 410078.,State Key Laboratory of Medical Genetics of China, Central South University, Changsha, China, 410078
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Roy V, Chenkual L, Gurusubramanian G. Mallotus roxburghianus modulates antioxidant responses in pancreas of diabetic rats. Acta Histochem 2016; 118:152-63. [PMID: 26764087 DOI: 10.1016/j.acthis.2015.12.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 12/20/2022]
Abstract
Mallotus roxburghianus has long been used by Mizo tribal people for the treatment of diabetes. Scientific validation at known doses may provide information about its safety and efficacy. Methanolic leaf extract of M. roxburghianus (MRME 100 and 400mg/kg) was tested in comparison with normal and alloxan diabetic rats for 28 days p.o. in terms of body and pancreatic weight, blood glucose level, antioxidant enzymes, expression of visfatin and PCNA, histopathology and histomorphometric measurements of pancreas. The results were evaluated statistically using ANOVA, correlation and regression and Principal component analysis (PCO). MRME (100 and 400mg/kg) treatment significantly (p<0.0001) decreased the body weight, blood glucose level, improved the mass and size of pancreas, elevated the levels of antioxidant enzymes and up regulate the expression of visfatin and PCNA. PCO analysis was good to fitness and prediction distinguishes the therapeutic effects of M. roxburghianus from the alloxan induced diabetic rats. MRME has significant role in protecting animals from alloxan-induced diabetic oxidative stress in pancreas and exhibited promising antihyperglycaemic and antioxidant activities along with significant reversal of disturbed antioxidant status and lipid peroxidative damage. Pancreatic architecture and physiology under diabetic oxidative stress have been significantly modulated by MRME and validated as a drug candidate for antidiabetic treatment. M. roxburghianus treatment restores the antioxidant enzyme system and rejuvenates the islets mass in alloxanized rat by accelerating visfatin and PCNA expression in pancreatic tissue.
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Donepudi AC, Cheng Q, Lu ZJ, Cherrington NJ, Slitt AL. Hepatic Transporter Expression in Metabolic Syndrome: Phenotype, Serum Metabolic Hormones, and Transcription Factor Expression. ACTA ACUST UNITED AC 2016; 44:518-26. [PMID: 26847773 DOI: 10.1124/dmd.115.066779] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 01/16/2016] [Indexed: 12/15/2022]
Abstract
Metabolic syndrome is a multifactorial disease associated with obesity, insulin resistance, diabetes, and the alteration of multiple metabolic hormones. Obesity rates have been rising worldwide, which increases our need to understand how this population will respond to drugs and exposure to other chemicals. The purpose of this study was to determine in lean and obese mice the ontogeny of clinical biomarkers such as serum hormone and blood glucose levels as well as the physiologic markers that correlate with nuclear receptor- and transporter-related pathways. Livers from male and female wild-type (WT) (C57BL/6) and ob/ob mice littermates were collected before, during, and after the onset of obesity. Serum hormone and mRNA levels were analyzed. Physiologic changes and gene expression during maturation and progression to obesity were performed and correlation analysis was performed using canonical correlations. Significant ontogenic changes in both WT and ob/ob mice were observed and these ontogenic changes differ in ob/ob mice with the development of obesity. In males and females, the ontogenic pattern of the expression of genes such as Abcc3, 4, Abcg2, Cyp2b10, and 4a14 started to differ from week 3, and became significant at weeks 4 and 8 in ob/ob mice compared with WT mice. In obese males, serum resistin, glucagon, and glucose levels correlated with the expression of most hepatic ATP-binding cassette (Abc) transporters, whereas in obese females, serum glucagon-like peptide 1 levels were correlated with most hepatic uptake transporters and P450 enzymes. Overall, the correlation between physiologic changes and gene expression indicate that metabolism-related hormones may play a role in regulating the genes involved in drug metabolism and transport.
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Affiliation(s)
- Ajay C Donepudi
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (A.C.D., Q.C, A.L.S); Arizona Statistical Consulting Laboratory, The Bio5 Institute (Z.J.L.) and Department of Pharmacology and Toxicology, College of Pharmacy (N.J.C.), University of Arizona, Tucson, Arizona
| | - Qiuqiong Cheng
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (A.C.D., Q.C, A.L.S); Arizona Statistical Consulting Laboratory, The Bio5 Institute (Z.J.L.) and Department of Pharmacology and Toxicology, College of Pharmacy (N.J.C.), University of Arizona, Tucson, Arizona
| | - Zhenqiang James Lu
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (A.C.D., Q.C, A.L.S); Arizona Statistical Consulting Laboratory, The Bio5 Institute (Z.J.L.) and Department of Pharmacology and Toxicology, College of Pharmacy (N.J.C.), University of Arizona, Tucson, Arizona
| | - Nathan J Cherrington
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (A.C.D., Q.C, A.L.S); Arizona Statistical Consulting Laboratory, The Bio5 Institute (Z.J.L.) and Department of Pharmacology and Toxicology, College of Pharmacy (N.J.C.), University of Arizona, Tucson, Arizona
| | - Angela L Slitt
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island (A.C.D., Q.C, A.L.S); Arizona Statistical Consulting Laboratory, The Bio5 Institute (Z.J.L.) and Department of Pharmacology and Toxicology, College of Pharmacy (N.J.C.), University of Arizona, Tucson, Arizona
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Choi JM, Oh SJ, Lee SY, Im JH, Oh JM, Ryu CS, Kwak HC, Lee JY, Kang KW, Kim SK. HepG2 cells as an in vitro model for evaluation of cytochrome P450 induction by xenobiotics. Arch Pharm Res 2014; 38:691-704. [PMID: 25336106 DOI: 10.1007/s12272-014-0502-6] [Citation(s) in RCA: 212] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 10/15/2014] [Indexed: 01/14/2023]
Abstract
Although various in vitro assays have been developed to evaluate the cytochrome P450 (CYP)-inducing potential of drug candidates, there is a continuing need for the development of a reliable model in drug discovery. The objective of the present study was to compare CYP induction by chemicals in HepG2 cells with Huh7, NKNT-3, and reverted NKNT-3 cells. HepG2 cells showed more similarity to human liver than the other cell lines in comparisons of the expression of cellular proteins. In evaluation of basal CYP activity, Huh7 cells exhibited the highest CYP1A2 and CYP3A4 activity, and HepG2 cells showed the highest CYP2B6 activity. The inducibility of CYP1A2, CYP2B6, and CYP3A4 by prototypical inducers was determined using enzyme assay, immunoblot analysis, and real-time PCR. Among the cells tested, HepG2 cells were highly responsive to CYP inducers, such as 3-methylcholanthrene for CYP1A2 and phenobarbital for CYP2B6 and CYP3A4. Moreover, HepG2 cells were responsive to various CYP1A2, CYP2B6, and CYP3A4 inducers as determined using fluorogenic and LC-MS/MS substrates. Thus, HepG2 cells may be comparable to human hepatocytes for the evaluation of CYP induction or slightly less sensitive. These results suggest HepG2 cells as a cell-based model in screening for CYP inducers in drug discovery.
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Affiliation(s)
- Jong Min Choi
- College of Pharmacy, Chungnam National University, Daejeon, 305-764, Republic of Korea
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Nteeba J, Ganesan S, Keating AF. Impact of obesity on ovotoxicity induced by 7,12-dimethylbenz[a]anthracene in mice. Biol Reprod 2014; 90:68. [PMID: 24501177 DOI: 10.1095/biolreprod.113.114215] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Insulin, elevated during obesity, regulates xenobiotic biotransformation enzymes, potentially through phosphatidylinositol 3-kinase (PI3K) signaling, in extraovarian tissues. PI3K regulates oocyte viability, follicular activation, and ovarian chemical biotransformation. 7,12-Dimethylbenz[a]anthracene (DMBA), a carcinogen and ovotoxicant, destroys all stages of follicles, leading to premature ovarian failure. Obesity has been reported to promote DMBA-induced tumors, but it remains unknown whether obesity affects ovarian xenobiotic metabolism. Therefore, we investigated ovarian expression of xenobiotic metabolism genes-microsomal epoxide hydrolase (Ephx1), glutathione S-transferase (GST) class Pi (Gstp1) and class mu 1 (Gstm1), and PI3K-signaling members (protein kinase B [AKT] alpha [Akt1], beta [Akt2], and the forkhead transcription factor subfamily 3 [Foxo3])-in lean and obese female mice after DMBA exposure (1 mg/kg; intraperitoneal injection for 14 days). Relative to lean, obese mice had decreased (P < 0.05) healthy primordial and primary follicle numbers but increased (P < 0.05) secondary and preovulatory follicles numbers. Obesity increased (P < 0.05) Akt1, Akt2, Gstm1, and Ephx1 mRNA and pAKT(Ser473/Thr308), GSTM1, GSTP1, and EPHX1 protein levels. DMBA decreased (P < 0.05) ovarian weight in lean and obese mice, however, obese DMBA-treated females had a greater reduction (P < 0.05) in ovarian weight. In both lean and obese mice, DMBA decreased (P < 0.05) all stages of healthy follicle numbers, increased Gstp1 and Ephx1 mRNA as well as GSTM1, GSTP1, and EPHX1 protein levels, and decreased Akt1 and Akt2 mRNA as well as pAKT(Ser473) or pAKT(Thr308), FOXO3, and pFOXO3(Ser253) protein expression. There was an additive effect between obesity and DMBA exposure for increased Gstm1 and Ephx1 mRNA as well as GSTM1 and EPHX1 protein expression.
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Affiliation(s)
- Jackson Nteeba
- Department of Animal Science, Iowa State University, Ames, Iowa
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Gender-dependent expression of pancreatic proteins in streptozotocin-induced diabetic rats. BIOTECHNOL BIOPROC E 2014. [DOI: 10.1007/s12257-013-0324-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Expression of hepatic antioxidant enzymes in non-obese type-2 diabetic Goto-Kakizaki rats. Arch Pharm Res 2013; 37:1345-53. [PMID: 24254933 DOI: 10.1007/s12272-013-0267-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 10/15/2013] [Indexed: 10/26/2022]
Abstract
Diabetes mellitus and its complications have been attributed in part to oxidative stress, against which antioxidant enzymes constitute a major protective mechanism. The present study was performed to investigate the effects of early stage type 2 diabetes in the absence of obesity and liver damage on hepatic antioxidant enzyme expression and oxidative stress using 9-week-old Goto-Kakizaki (GK) rats. Hepatic total antioxidant capacity determined by total oxygen radical scavenging capacity and lipid peroxidation determined by malondialdehyde in plasma and liver were not significantly different between normal Wistar rats and GK rats. These results indicated that oxidative stress is not evident in these type 2 diabetic rats. Hepatic expression levels of antioxidant enzymes, including superoxide dismutase-1, catalase, glutathione peroxidase and reductase, thioredoxin-1, mu- and pi-class glutathione S-transferase (GST), and the gamma-glutamylcysteine ligase catalytic subunit, were not different between normal rats and GK rats. But, hepatic level and activity of alpha-class GST were decreased and peroxiredoxin-1 level was increased in GK rats, suggesting that upregulation of peroxiredoxin-1 compensates for downregulation of alpha-class GST. These results suggest that alpha-class GST and peroxiredoxin-1 in liver can be altered during the early stages of type 2 diabetes in the absence of obesity and severe oxidative stress.
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Role of NADPH oxidase-4 in saturated fatty acid-induced insulin resistance in SK-Hep-1 cells. Food Chem Toxicol 2013; 63:128-35. [PMID: 24211519 DOI: 10.1016/j.fct.2013.10.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/28/2013] [Accepted: 10/31/2013] [Indexed: 11/20/2022]
Abstract
We aimed to develop a cell culture model of type 2 diabetes by treating SK-Hep-1 cells with four free fatty acids [i.e., palmitic acid, stearic acid (SA), linoleic acid and oleic acid]. The results showed that Akt phosphorylation was increased in SK-Hep-1 cells treated with insulin in a time- and concentration-dependent manner, which was inhibited by saturated fatty acids, but not by unsaturated fatty acids. Moreover, protein levels of NADPH oxidase (NOX) 4 but not NOX2 were increased following SA treatment and, consequently, increased reactive oxygen species production and decreased cellular glutathione were observed. Apocynin, a NOX4 inhibitor, restored the SA-induced inhibition of Akt phosphorylation, suggesting the role of NOX4 in insulin resistance induced by SA. Neither phosphorylation level nor protein level of the stress signaling kinases, such as c-Jun N-terminal kinase or p38 mitogen activated protein kinase, was changed by SA treatment. Although binding immunoglobulin protein, a marker of endoplasmic reticulum stress, was transiently increased in SKHep-1 cells treated with SA, 4-phenyl butyric acid, a chemical chaperone, had no effect on the insulin-mediated Akt phosphorylation inhibited by SA. The present study provides a useful model for screening anti-insulin resistance drugs and finding new drug targets for treatment of diabetes.
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Nteeba J, Ross JW, Perfield JW, Keating AF. High fat diet induced obesity alters ovarian phosphatidylinositol-3 kinase signaling gene expression. Reprod Toxicol 2013; 42:68-77. [PMID: 23954404 DOI: 10.1016/j.reprotox.2013.07.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 12/17/2022]
Abstract
Insulin regulates ovarian phosphatidylinositol-3-kinase (PI3 K) signaling, important for primordial follicle viability and growth activation. This study investigated diet-induced obesity impacts on: (1) insulin receptor (Insr) and insulin receptor substrate 1 (Irs1); (2) PI3K components (Kit ligand (Kitlg), kit (c-Kit), protein kinase B alpha (Akt1) and forkhead transcription factor subfamily 3 (Foxo3a)); (3) xenobiotic biotransformation (microsomal epoxide hydrolase (Ephx1), Cytochrome P450 isoform 2E1 (Cyp2e1), Glutathione S-transferase (Gst) isoforms mu (Gstm) and pi (Gstp)) and (4) microRNA's 184, 205, 103 and 21 gene expression. INSR, GSTM and GSTP protein levels were also measured. Obese mouse ovaries had decreased Irs1, Foxo3a, Cyp2e1, MiR-103, and MiR-21 but increased Kitlg, Akt1, and miR-184 levels relative to lean littermates. These results support that diet-induced obesity potentially impairs ovarian function through aberrant gene expression.
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Affiliation(s)
- J Nteeba
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA.
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Gupta R, Sharma AK, Sharma MC, Gupta RS. Antioxidant activity and protection of pancreatic β-cells by embelin in streptozotocin-induced diabetes. J Diabetes 2012; 4:248-56. [PMID: 22252046 DOI: 10.1111/j.1753-0407.2012.00187.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVES The aim of the present study was to evaluate the antioxidant potential of embelin in streptozotocin-induced diabetes. METHODS Diabetes was induced in rats fasted overnight by the administration of a single dose of streptozotocin, and analyzed for blood, serum, and biological and histological pancreatic tissue parameters in intact control, diabetic, and embelin-treated diabetic rats (n = 9) at the dose levels of 15, 25, and 30 mg/kg/day for 21 days. RESULTS Diabetes caused highly significant abnormalities in blood, serum, and pancreatic tissue biochemical parameters. Embelin and glibenclamide administration to diabetic rats caused a highly significant decline in the blood glycated hemoglobin and serum glucose levels and nitric oxide activity, with a concomitant increase in the serum insulin level (P < 0.001). Furthermore, embelin and glibenclamide treatment increased the pancreatic antioxidant enzyme status (superoxide dismutase, catalase, reduced glutathione, glutathione peroxidase, glutathione S-transferase, and ascorbic acid), and also decreased the thiobarbituric acid reactive oxygen species contents (P < 0.001). The histoarchitecture of the diabetic rats typically showed a degenerated pancreas with reduced β-cell counts, while embelin treatment was shown to significantly regenerate islet cells. CONCLUSION The study proves the potent antioxidant activity of embelin, which has been found to be effective in managing severe hyperglycemia.
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Affiliation(s)
- Rajnish Gupta
- Department of Zoology, University of Rajasthan, Jaipur, India.
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Effects of palmitic acid on TNF-α-induced cytotoxicity in SK-Hep-1 cells. Toxicol In Vitro 2012; 26:783-90. [DOI: 10.1016/j.tiv.2012.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 05/15/2012] [Accepted: 05/29/2012] [Indexed: 01/14/2023]
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18
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Expression of hepatic and ovarian antioxidant enzymes during estrous cycle in rats. Toxicol Lett 2012; 212:329-36. [DOI: 10.1016/j.toxlet.2012.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 06/05/2012] [Accepted: 06/09/2012] [Indexed: 01/23/2023]
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Gupta R, Sharma AK, Sharma M, Dobhal M, Gupta R. Evaluation of antidiabetic and antioxidant potential of lupeol in experimental hyperglycaemia. Nat Prod Res 2012; 26:1125-9. [DOI: 10.1080/14786419.2011.560845] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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Bhattacharya P, Keating AF. Protective role for ovarian glutathione S-transferase isoform pi during 7,12-dimethylbenz[a]anthracene-induced ovotoxicity. Toxicol Appl Pharmacol 2012; 260:201-8. [PMID: 22406437 PMCID: PMC3319246 DOI: 10.1016/j.taap.2012.02.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 02/20/2012] [Accepted: 02/21/2012] [Indexed: 02/06/2023]
Abstract
7,12-Dimethylbenz[a]anthracene (DMBA) destroys ovarian follicles at all developmental stages. This study investigated a role for the glutathione S-transferase (Gst) isoforms alpha (a), mu (m) and pi (p) and the transcription factors, Ahr and Nrf2, during DMBA-induced ovotoxicity, and their regulation by phosphatidylinositol-3 kinase (PI3K) signaling. Negative regulation of JNK by GSTP during DMBA exposure was also studied. Post-natal day (PND) 4 Fischer 344 rat ovaries were exposed to vehicle control (1% DMSO)±DMBA (1 μM) or vehicle control (1% DMSO)±LY294002 (PI3K inhibitor; 20 μM) for 1, 2, 4, or 6 days. Total RNA or protein was isolated, followed by RT-PCR or Western blotting to determine mRNA or protein level, respectively. Immunoprecipitation using an anti-GSTP antibody was performed to determine interaction between GSTP and JNK, followed by Western blotting to determine JNK and p-c-Jun protein level. DMBA had no impact on Gsta, Gstm or Nrf2 mRNA level, but increased Gstp mRNA and protein after 2 days. Ahr mRNA and protein increased after 2 and 4 days of DMBA exposure, respectively and DMBA increased NRF2 protein level after 4 days. JNK bound to GSTP was increased during DMBA exposure, with a concomitant decrease in unbound JNK and p-c-Jun. Ahr and Gstp mRNA were decreased (2 days) and increased (4 days) by PI3K inhibition, while Gstm mRNA increased (P<0.05) after both time points, and there was no effect on Nrf2 mRNA. PI3K inhibition increased AHR, NRF2 and GSTP protein level. These findings support involvement of ovarian GSTP during DMBA exposure, and indicate a regulatory role for the PI3K signaling pathway on ovarian xenobiotic metabolism gene expression.
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Affiliation(s)
| | - Aileen F. Keating
- Department of Animal Science, Iowa State University, Ames, IA 50011, USA
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21
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Villanueva SSM, Perdomo VG, Ruiz ML, Rigalli JP, Arias A, Luquita MG, Vore M, Catania VA, Mottino AD. Effect of glucagon-like peptide 2 on hepatic, renal, and intestinal disposition of 1-chloro-2,4-dinitrobenzene. Drug Metab Dispos 2012; 40:1252-8. [PMID: 22453052 DOI: 10.1124/dmd.111.044339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ability of the liver, small intestine, and kidney to synthesize and subsequently eliminate dinitrophenyl-S-glutathione (DNP-SG), a substrate for multidrug resistance-associated protein 2 (Mrp2), was assessed in rats treated with glucagon-like peptide 2 (GLP-2, 12 μg/100 g b.wt. s.c. every 12 h for 5 consecutive days). An in vivo perfused jejunum model with simultaneous bile and urine collection was used. A single intravenous dose of 30 μmol/kg b.wt. 1-chloro-2,4-dinitrobenzene (CDNB) was administered, and its conjugate, DNP-SG, and dinitrophenyl cysteinyl glycine (DNP-CG), resulting from the action of γ-glutamyltransferase on DNP-SG, were determined in bile, intestinal perfusate, and urine by high-performance liquid chromatography. Tissue content of DNP-SG was also assessed in liver, intestine, and kidneys. Biliary excretion of DNP-SG+DNP-CG was decreased in GLP-2 rats with respect to controls. In contrast, their intestinal excretion was substantially increased, whereas urinary elimination was not affected. Western blot and real-time polymerase chain reaction studies revealed preserved levels of Mrp2 protein and mRNA in liver and renal cortex and a significant increase in intestine in response to GLP-2 treatment. Tissue content of DNP-SG detected 5 min after CDNB administration was decreased in liver, increased in intestine, and unchanged in kidney in GLP-2 versus control group, consistent with GLP-2-induced down-regulation of expression of glutathione transferase (GST) Mu in liver and up-regulation of GST-Alpha in intestine at both protein and mRNA levels. In conclusion, GLP-2 induced selective changes in hepatic and intestinal disposition of a common GST and Mrp2 substrate administered systemically that could be of pharmacological or toxicological relevance under therapeutic treatment conditions.
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Affiliation(s)
- Silvina S M Villanueva
- Instituto de Fisiología Experimental, Facultad de Ciencias Bioquímicas y Farmacéuticas, Suipacha 570, S2002LRL Rosario, Argentina
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Wang X, Tao L, Hai CX. Redox-regulating role of insulin: the essence of insulin effect. Mol Cell Endocrinol 2012; 349:111-27. [PMID: 21878367 DOI: 10.1016/j.mce.2011.08.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/10/2011] [Accepted: 08/14/2011] [Indexed: 11/18/2022]
Abstract
It is well-known that insulin acts as an important hormone, controlling energy metabolism, cellular proliferation and biosynthesis of functional molecules to maintain a biological homeostasis. Over the past few years, intensive insulin therapy has been believed to be benefit for the outcome of diabetic patients, in which the suppression of oxidative stress plays a role. Moreover, insulin is accepted as a key component of glucose-insulin-potassium, a treatment which has been believed to exert significant cardiovascular protective effect via the reduction of oxidative stress. Furthermore, accumulating evidence has suggested that insulin exerts important redox-regulating actions in various insulin-sensitive target organs, implying the systematic antioxidative role of insulin as a hormone. It is time for us to revisit insulin effects, through summarizing and evaluating the novel functions of insulin and their mechanisms. This review focuses on the antioxidative effect of insulin and highlights insulin-induced regulation of various antioxidant enzymes via insulin signaling pathways and the cross talk between key transcription factors, including nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor κB (NF-κB) which are responsible for the transcription of antioxidant enzymes, leading to reduced generation of reactive oxygen species (ROS) and the enhancement of the elimination of ROS.
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Affiliation(s)
- Xin Wang
- Department of Toxicology, School of Preventive Medicine, The Fourth Military Medical University, Xi'an 710032, China
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Duarte AI, Moreira PI, Oliveira CR. Insulin in central nervous system: more than just a peripheral hormone. J Aging Res 2012; 2012:384017. [PMID: 22500228 PMCID: PMC3303591 DOI: 10.1155/2012/384017] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 10/12/2011] [Accepted: 11/23/2011] [Indexed: 12/14/2022] Open
Abstract
Insulin signaling in central nervous system (CNS) has emerged as a novel field of research since decreased brain insulin levels and/or signaling were associated to impaired learning, memory, and age-related neurodegenerative diseases. Thus, besides its well-known role in longevity, insulin may constitute a promising therapy against diabetes- and age-related neurodegenerative disorders. More interestingly, insulin has been also faced as the potential missing link between diabetes and aging in CNS, with Alzheimer's disease (AD) considered as the "brain-type diabetes." In fact, brain insulin has been shown to regulate both peripheral and central glucose metabolism, neurotransmission, learning, and memory and to be neuroprotective. And a future challenge will be to unravel the complex interactions between aging and diabetes, which, we believe, will allow the development of efficient preventive and therapeutic strategies to overcome age-related diseases and to prolong human "healthy" longevity. Herewith, we aim to integrate the metabolic, neuromodulatory, and neuroprotective roles of insulin in two age-related pathologies: diabetes and AD, both in terms of intracellular signaling and potential therapeutic approach.
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Affiliation(s)
- Ana I. Duarte
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Paula I. Moreira
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
- Institute of Physiology, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal
| | - Catarina R. Oliveira
- CNC, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
- Institute of Biochemistry, Faculty of Medicine, University of Coimbra, 3000-354 Coimbra, Portugal
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Oh SJ, Choi JM, Yun KU, Oh JM, Kwak HC, Oh JG, Lee KS, Kim BH, Heo TH, Kim SK. Hepatic expression of cytochrome P450 in type 2 diabetic Goto-Kakizaki rats. Chem Biol Interact 2012; 195:173-9. [PMID: 22244987 DOI: 10.1016/j.cbi.2011.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Revised: 12/28/2011] [Accepted: 12/28/2011] [Indexed: 10/14/2022]
Abstract
Although hepatic expression of cytochrome P450 (CYP) changes markedly in diabetes, the role of ketone bodies in the regulation of CYP in diabetes is controversial. The present study was performed to determine the expression and activity of CYP in non-obese type II diabetic Goto-Kakizaki (GK) rats with normal levels of ketone bodies. In the present study, basal serum glucose levels increased 1.95-fold in GK rats, but acetoacetate and β-hydroxybutyrate levels were not significantly different. Hepatic expression of CYP reductase and CYP3A2 was up-regulated in the GK rats, and consequently, activities of CYP reductase and midazolam 4-hydroxylase, mainly catalyzed by CYP3A2, increased. In contrast, hepatic expression of CYP1A2 and CYP3A1 was down-regulated and the activities of 7-ethoxyresorufin-O-deethylase and 7-methoxyresorufin-O-demethylase, mainly catalyzed by CYP1A, also decreased in GK rats. Hepatic levels of microsomal protein and total CYP and hepatic expression of cytochrome b(5), CYP1B1, CYP2B1 and CYP2C11 were not significantly different between the GK rats and normal Wistar rats. Moreover, the expression and activity of CYP2E1, reported to be up-regulated in diabetes with hyperketonemia, were not significantly different between GK rats and control rats, suggesting that elevation of ketone bodies plays a critical role in the up-regulation of hepatic CYP2E1 in diabetic rats. Our results showed that the expression of hepatic CYP is regulated in an isoform-specific manner. The present results also show that the GK rat is a useful animal model for the pathophysiological study of non-obese type II diabetes with normal ketone body levels.
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Affiliation(s)
- Soo Jin Oh
- College of Pharmacy, Chungnam National University, Daejeon 305-764, Republic of Korea
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25
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Gupta R, Sharma AK, Dobhal MP, Sharma MC, Gupta RS. Antidiabetic and antioxidant potential of β-sitosterol in streptozotocin-induced experimental hyperglycemia. J Diabetes 2011; 3:29-37. [PMID: 21143769 DOI: 10.1111/j.1753-0407.2010.00107.x] [Citation(s) in RCA: 185] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Oxidative stress, produced under diabetic conditions, may cause tissue damage. Although several drugs are currently available for the treatment of diabetes, their continued use may cause unwanted side effects. The aim of the present study was to evaluate the antioxidant potential of β-sitosterol (BS), a phytosterol from Solanum surattense, using an experimental model for diabetes-induced oxidative damage. METHODS The effects of 21 days treatment with BS (10, 15 and 20 mg/kg, p.o.) on blood, serum, and tissue biochemical parameters were evaluated in control and streptozotocin-induced diabetic rats. Nine experimental groups, including a control group, a diabetic group, and BS- and glibenclamide-treated diabetic groups, were evaluated. RESULTS All three dose levels dose dependently resulted in decreases in glycated hemoglobin, serum glucose, and nitric oxide, with concomitant increases in serum insulin levels. Furthermore, treatment with BS doses also increased pancreatic antioxidant levels, with a concomitant decrease in thiobarbituric acid-reactive substances. CONCLUSIONS β-Sitosterol has promising antidiabetic as well as antioxidant effects and may be considered in clinical studies for drug development.
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Affiliation(s)
- Rajnish Gupta
- Reproductive Physiology Section, Centre for Advanced Studies, Department of Zoology, University of Rajasthan, Jaipur, India
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27
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Koide CL, Collier AC, Berry MJ, Panee J. The effect of bamboo extract on hepatic biotransforming enzymes--findings from an obese-diabetic mouse model. JOURNAL OF ETHNOPHARMACOLOGY 2011; 133:37-45. [PMID: 20832461 PMCID: PMC3471658 DOI: 10.1016/j.jep.2010.08.062] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 08/26/2010] [Accepted: 08/31/2010] [Indexed: 05/23/2023]
Abstract
AIM OF THE STUDY Bamboo leaves are used as a component in traditional Chinese medicine for the anti-inflammatory function. Our previous studies have demonstrated that an ethanol/water extract from Phyllostachys edulis ameliorated obesity-associated chronic systemic inflammation in mice, and therefore relieving the symptoms of type 2 diabetes. The aim of this project was to further investigate the effects of this bamboo extract on hepatic biotransformation enzymes in both lean and obese mice, as an initial step in the toxicological evaluation of using this traditional medicine in obese/diabetic population. MATERIALS AND METHODS Male C57BL/6J mice were randomized to 4 groups and fed standard (10% kcal from fat) diet with or without bamboo extract supplementation at a dose of 10 gram per kilogram diet (n=10 and n=9, respectively), or high fat (45% kcal from fat) diet with or without bamboo extract (n=8 and N=7, respectively). The dietary treatment lasted for 6 months. Subsequently, the activities and expression of the major Phase I and II hepatic biotransformation enzymes were assessed in subcellular fractions from murine livers. RESULTS Three groups of mice, lean bamboo extract-supplemented, obese/diabetic, and bamboo extract-supplemented obese/diabetic, showed greater activities of cytochromes P450 1a2 and 3a11 compared to control but no changes in the expression level of these proteins. For Phase II enzymes, bamboo extract supplementation in lean mice caused decreased glutathione-S-transferase activity (-12%) and greater uridine diphosphate glucuronosyltransferase activity (+46%), but had no effect on sulfotransferase activity. Conversely, the obese/diabetic condition itself increased glutathione-S-transferase and uridine diphosphate glucuronosyltransferase activities, but decreased total sulfotransferase activity and sulfotransferase 2a1 expression. CONCLUSIONS Bamboo extract and obesity/diabetes show significant independent effects on hepatic biotransformation as well as interaction effects in mice. These changes may alter the clearance of endo- and xenobiotics, including bamboo extract itself, hence this effect should be carefully considered in the medicinal application of bamboo extract as it has potential to alter its own metabolism and that of other medications concurrently administered to obese diabetic patients.
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Affiliation(s)
- Cheryl L.K. Koide
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, United States
| | - Abby C. Collier
- Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, United States
| | - Marla J. Berry
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, United States
| | - Jun Panee
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street BSB 222, Honolulu, HI 96813, United States
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Sakhi AK, Berg TJ. Reduced glutathione concentrations are not decreased in red blood cells of patients with long term type 1-diabetes. Scand J Clin Lab Invest 2010; 71:108-11. [DOI: 10.3109/00365513.2010.536851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Evaluation of antioxidant defense systems in H4IIE cells infected with a retroviral vector. Toxicol In Vitro 2010; 24:1105-10. [DOI: 10.1016/j.tiv.2010.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 02/02/2010] [Accepted: 03/17/2010] [Indexed: 01/11/2023]
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Ballatori N, Krance SM, Notenboom S, Shi S, Tieu K, Hammond CL. Glutathione dysregulation and the etiology and progression of human diseases. Biol Chem 2009; 390:191-214. [PMID: 19166318 DOI: 10.1515/bc.2009.033] [Citation(s) in RCA: 731] [Impact Index Per Article: 48.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glutathione (GSH) plays an important role in a multitude of cellular processes, including cell differentiation, proliferation, and apoptosis, and as a result, disturbances in GSH homeostasis are implicated in the etiology and/or progression of a number of human diseases, including cancer, diseases of aging, cystic fibrosis, and cardiovascular, inflammatory, immune, metabolic, and neurodegenerative diseases. Owing to the pleiotropic effects of GSH on cell functions, it has been quite difficult to define the role of GSH in the onset and/or the expression of human diseases, although significant progress is being made. GSH levels, turnover rates, and/or oxidation state can be compromised by inherited or acquired defects in the enzymes, transporters, signaling molecules, or transcription factors that are involved in its homeostasis, or from exposure to reactive chemicals or metabolic intermediates. GSH deficiency or a decrease in the GSH/glutathione disulfide ratio manifests itself largely through an increased susceptibility to oxidative stress, and the resulting damage is thought to be involved in diseases, such as cancer, Parkinson's disease, and Alzheimer's disease. In addition, imbalances in GSH levels affect immune system function, and are thought to play a role in the aging process. Just as low intracellular GSH levels decrease cellular antioxidant capacity, elevated GSH levels generally increase antioxidant capacity and resistance to oxidative stress, and this is observed in many cancer cells. The higher GSH levels in some tumor cells are also typically associated with higher levels of GSH-related enzymes and transporters. Although neither the mechanism nor the implications of these changes are well defined, the high GSH content makes cancer cells chemoresistant, which is a major factor that limits drug treatment. The present report highlights and integrates the growing connections between imbalances in GSH homeostasis and a multitude of human diseases.
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Affiliation(s)
- Nazzareno Ballatori
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY 14642, USA.
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Ki SH, Kim SG. Phase II enzyme induction by α-lipoic acid through phosphatidylinositol 3-kinase-dependent C/EBPs activation. Xenobiotica 2008; 38:587-604. [DOI: 10.1080/00498250802126920] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- S. H. Ki
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University , Seoul, Korea
| | - S. G. Kim
- Innovative Drug Research Center for Metabolic and Inflammatory Disease, College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University , Seoul, Korea
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Franco R, Schoneveld OJ, Pappa A, Panayiotidis MI. The central role of glutathione in the pathophysiology of human diseases. Arch Physiol Biochem 2007; 113:234-58. [PMID: 18158646 DOI: 10.1080/13813450701661198] [Citation(s) in RCA: 357] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reduced glutathione (L-gamma-glutamyl-L-cysteinyl-glycine, GSH) is the prevalent low-molecular-weight thiol in mammalian cells. It is formed in a two-step enzymatic process including, first, the formation of gamma-glutamylcysteine from glutamate and cysteine, by the activity of the gamma-glutamylcysteine synthetase; and second, the formation of GSH by the activity of GSH synthetase which uses gamma-glutamylcysteine and glycine as substrates. While its synthesis and metabolism occur intracellularly, its catabolism occurs extracellularly by a series of enzymatic and plasma membrane transport steps. Glutathione metabolism and transport participates in many cellular reactions including: antioxidant defense of the cell, drug detoxification and cell signaling (involved in the regulation of gene expression, apoptosis and cell proliferation). Alterations in its concentration have also been demonstrated to be a common feature of many pathological conditions including diabetes, cancer, AIDS, neurodegenerative and liver diseases. Additionally, GSH catabolism has been recently reported to modulate redox-sensitive components of signal transduction cascades. In this manuscript, we review the current state of knowledge on the role of GSH in the pathogenesis of human diseases with the aim to underscore its relevance in translational research for future therapeutic treatment design.
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Affiliation(s)
- R Franco
- Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
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Wang T, Shankar K, Ronis MJ, Mehendale HM. Mechanisms and outcomes of drug- and toxicant-induced liver toxicity in diabetes. Crit Rev Toxicol 2007; 37:413-59. [PMID: 17612954 DOI: 10.1080/10408440701215100] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increase dincidences of hepatotoxicity have been observed in diabetic patients receiving drug therapies. Neither the mechanisms nor the predisposing factors underlying hepatotoxicity in diabetics are clearly understood. Animal studies designed to examine the mechanisms of diabetes-modulated hepatotoxicity have traditionally focused only on bioactivation/detoxification of drugs and toxicants. It is becoming clear that once injury is initiated, additional events determine the final outcome of liver injury. Foremost among them are two leading mechanisms: first, biochemical mechanisms that lead to progression or regression of injury; and second, whether or not timely and adequate liver tissue repair occurs to mitigate injury and restore liver function. The liver has a remarkable ability to repair and restore its structure and function after physical or chemical-induced damage. The dynamic interaction between biotransformation-based liver injury and compensatory tissue repair plays a pivotal role in determining the ultimate outcome of hepatotoxicity initiated by drugs or toxicants. In this review, mechanisms underlying altered hepatotoxicity in diabetes with emphasis on both altered bioactivation and liver tissue repair are discussed. Animal models of both marked sensitivity (diabetic rats) and equally marked protection (diabetic mice) from drug-induced hepatotoxicity are described. These examples represent a remarkable species difference. Availability of the rodent diabetic models offers a unique opportunity to uncover mechanisms of clinical interest in averting human diabetic sensitivity to drug-induced hepatotoxicities. While the rat diabetic models appear to be suitable, the diabetic mouse models might not be suitable in preclinical testing for potential hepatotoxic effects of drugs or toxicants, because regardless of type 1 or type2 diabetes, mice are resistant to acute drug-or toxicant-induced toxicities.
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Affiliation(s)
- T Wang
- Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe, Monroe, Louisiana 71209, USA
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Kang KW, Kwak SH, Yun SY, Kim SK. Evaluation of Antioxidant Activity of Sugar Alcohols Using TOSC (Total Oxy-radical Scavenging Capacity) Assay. Toxicol Res 2007. [DOI: 10.5487/tr.2007.23.2.143] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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35
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Kim SK, Novak RF. The role of intracellular signaling in insulin-mediated regulation of drug metabolizing enzyme gene and protein expression. Pharmacol Ther 2006; 113:88-120. [PMID: 17097148 PMCID: PMC1828071 DOI: 10.1016/j.pharmthera.2006.07.004] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 07/18/2006] [Indexed: 12/28/2022]
Abstract
Endogenous factors, including hormones, growth factors and cytokines, play an important role in the regulation of hepatic drug metabolizing enzyme expression in both physiological and pathophysiological conditions. Diabetes, fasting, obesity, protein-calorie malnutrition and long-term alcohol consumption produce changes in hepatic drug metabolizing enzyme gene and protein expression. This difference in expression alters the metabolism of xenobiotics, including procarcinogens, carcinogens, toxicants and therapeutic agents, potentially impacting the efficacy and safety of therapeutic agents, and/or resulting in drug-drug interactions. Although the mechanisms by which xenobiotics regulate drug metabolizing enzymes have been studied intensively, less is known regarding the cellular signaling pathways and components which regulate drug metabolizing enzyme gene and protein expression in response to hormones and cytokines. Recent findings, however, have revealed that several cellular signaling pathways are involved in hormone- and growth factor-mediated regulation of drug metabolizing enzymes. Our laboratory has reported that insulin and growth factors regulate drug metabolizing enzyme gene and protein expression, including cytochromes P450 (CYP), glutathione S-transferases (GST) and microsomal epoxide hydrolase (mEH), through receptors which are members of the large receptor tyrosine kinase (RTK) family, and by downstream effectors such as phosphatidylinositol 3-kinase, mitogen activated protein kinase (MAPK), Akt/protein kinase B (PKB), mammalian target of rapamycin (mTOR), and the p70 ribosomal protein S6 kinase (p70S6 kinase). Here, we review current knowledge of the signaling pathways implicated in regulation of drug metabolizing enzyme gene and protein expression in response to insulin and growth factors, with the goal of increasing our understanding of how disease affects these signaling pathways, components, and ultimately gene expression and translational control.
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Affiliation(s)
- Sang K. Kim
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA
- College of Pharmacy and Research Center for Transgenic Cloned Pigs, Chungnam National University, Daejeon 305-764, South Korea
| | - Raymond F. Novak
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA
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Kim SK, Abdelmegeed MA, Novak RF. The mitogen-activated protein kinase kinase (mek) inhibitor PD98059 elevates primary cultured rat hepatocyte glutathione levels independent of inhibiting mek. Drug Metab Dispos 2006; 34:683-9. [PMID: 16443668 DOI: 10.1124/dmd.105.007666] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The antioxidant activity of flavonoids, directly through scavenging oxidizing species and indirectly through modulating drug-metabolizing enzyme activities, is associated with chemopreventive and chemotherapeutic effects. However, little published information is available concerning the effect of flavonoids on glutathione (GSH) homeostasis. We previously demonstrated that PD98059 (2'-amino-3'-methoxyflavone), a flavone derivative and selective mitogen-activated protein kinase kinase (MEK) 1 inhibitor, enhanced the insulin-mediated increase in GSH levels. To determine whether the PD98059-mediated increase in GSH levels was associated with MEK inhibition, primary cultured rat hepatocytes were treated with PD98059, the MEK inhibitor U0126, which is not a flavone derivative, or flavone. PD98059 increased GSH levels in a concentration-dependent manner in hepatocytes cultured in the presence or absence of insulin. In contrast, GSH levels were not affected by U0126 at concentrations sufficient to inhibit insulin-mediated extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Flavone, however, markedly increased GSH levels without inhibition of ERK1/2 phosphorylation. The concentration of GSH in the culture medium was also elevated by PD98059 or flavone, suggesting that the cellular GSH elevation could not be accounted for by the inhibition of GSH efflux into medium. Interestingly, PD98059 and flavone increased cellular cysteine levels, which may be responsible for the PD98059- and flavone-mediated elevation of GSH levels. These results provide evidence that PD98059 and flavone produce dramatic changes in GSH homeostasis in hepatocytes, through a mechanism(s) unrelated to MEK inhibition. Moreover, the current study implies that flavonoid-induced chemopreventive and chemotherapeutic effects may be mediated by regulation of redox state through the stimulation of GSH synthesis.
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Affiliation(s)
- Sang K Kim
- Institute of Environmental Health Sciences, Wayne State University, 2727 Second Ave., Room 4000, Detroit, MI 48201, USA
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Kim SK, Abdelmegeed MA, Novak RF. Identification of the insulin signaling cascade in the regulation of alpha-class glutathione S-transferase expression in primary cultured rat hepatocytes. J Pharmacol Exp Ther 2005; 316:1255-61. [PMID: 16293713 DOI: 10.1124/jpet.105.096065] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We reported previously that insulin elevated alpha-class glutathione S-transferase (GSTs) protein levels in primary cultured rat hepatocytes (Kim et al., 2003b). In contrast, glucagon down-regulated alpha- and pi-class GST expression, and mechanistic research implicated cAMP and protein kinase A in this process (Kim et al., 2003b). The present study examines the signaling pathways involved in the regulation of alpha-class GST in response to insulin in primary cultured rat hepatocytes. Protein levels of GSTA1/2 and GSTA3/5 and activity of GST toward 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD) were increased in an insulin concentration-dependent manner. Treatment of cells with the phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin and LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one] or rapamycin, an inhibitor of mammalian target of rapamycin and ribosomal p70 S6 kinase (p70S6K) phosphorylation, or with an adenovirus containing green fluorescent protein and a dominant-negative and kinase-dead Akt, effectively inhibited the insulin-mediated increase in alpha-class GST expression and GST activity toward NBD. In contrast, PD98059 (2'-amino-3'-methoxyflavone), an inhibitor of mitogen-activated protein kinase kinase, SP600125 (1,9-pyrazoloanthrone), an inhibitor of c-Jun N-terminal kinase, SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imadazole], an inhibitor of p38 mitogen-activated protein kinase, or bisindolylmaleimide, a broad spectrum inhibitor of protein kinase C, did not inhibit the insulin-mediated increase in alpha-class GST protein levels in hepatocytes. These results show that PI3K/Akt/p70S6K signaling is active in the insulin-mediated up-regulation of the antioxidant defense system and that low insulin levels, as encountered in diabetes, potentially increase the susceptibility of hepatocytes to xenobiotic-mediated and/or oxidative stress-mediated damage.
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Affiliation(s)
- Sang K Kim
- Institute of Environmental Health Sciences, Wayne State University, 2727 South Avenue, Room 4000, Detroit, MI 48201, USA
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Duarte AI, Santos MS, Oliveira CR, Rego AC. Insulin neuroprotection against oxidative stress in cortical neurons--involvement of uric acid and glutathione antioxidant defenses. Free Radic Biol Med 2005; 39:876-89. [PMID: 16140208 DOI: 10.1016/j.freeradbiomed.2005.05.002] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Revised: 04/29/2005] [Accepted: 05/04/2005] [Indexed: 12/26/2022]
Abstract
In this study we investigated the effect of insulin on neuronal viability and antioxidant defense mechanisms upon ascorbate/Fe2+-induced oxidative stress, using cultured cortical neurons. Insulin (0.1 and 10 microM) prevented the decrease in neuronal viability mediated by oxidative stress, decreasing both necrotic and apoptotic cell death. Moreover, insulin inhibited ascorbate/Fe2+-mediated lipid and protein oxidation, thus decreasing neuronal oxidative stress. Increased 4-hydroxynonenal (4-HNE) adducts on GLUT3 glucose transporters upon exposure to ascorbate/Fe2+ were also prevented by insulin, suggesting that this peptide can interfere with glucose metabolism. We further analyzed the influence of insulin on antioxidant defense mechanisms in the cortical neurons. Oxidative stress-induced decreases in intracellular uric acid and GSH/GSSG levels were largely prevented upon treatment with insulin. Inhibition of phosphatidylinositol-3-kinase (PI-3K) or mitogen-induced extracellular kinase (MEK) reversed the effect of insulin on uric acid and GSH/GSSG, suggesting the activation of insulin-mediated signaling pathways. Moreover, insulin stimulated glutathione reductase (GRed) and inhibited glutathione peroxidase (GPx) activities under oxidative stress conditions, further supporting that insulin neuroprotection was related to the modulation of the glutathione redox cycle. Thus, insulin may be useful in preventing oxidative stress-mediated injury that occurs in several neurodegenerative disorders.
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Affiliation(s)
- Ana I Duarte
- Department of Zoology, Faculty of Sciences and Technology, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal
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Kim SK, Woodcroft KJ, Khodadadeh SS, Novak RF. Insulin signaling regulates gamma-glutamylcysteine ligase catalytic subunit expression in primary cultured rat hepatocytes. J Pharmacol Exp Ther 2004; 311:99-108. [PMID: 15169830 DOI: 10.1124/jpet.104.070375] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Decreased glutathione (GSH) levels and gamma-glutamylcysteine ligase (GCL) activity have been observed in diabetic patients, and insulin reportedly increases GSH synthesis via increased GCL catalytic subunit (GCLC) gene expression. The signaling pathways responsible for mediating insulin effects on GCLC expression and GSH levels, however, are unknown. The signaling pathways involved in the regulation of GSH synthesis in response to insulin were examined in primary cultured rat hepatocytes. GSH levels, GCL activity, GCLC protein, and mRNA levels were increased to 140, 160, 600, and 340% of that monitored in untreated cells, respectively, in hepatocytes cultured with 100 nM insulin. The phosphatidylinositol 3-kinase (PI3K) inhibitors, wortmannin and LY294002 [2-(4-morpholinyl)-9-phenyl-4H-1-benzopyran-4-one], dominant-negative Akt, or rapamycin, an inhibitor of mTOR (mammalian target of rapamycin) and ribosomal p70 S6 kinase (p70S6K) phosphorylation, inhibited the insulin-mediated increase in GCLC protein and GSH levels. Although the mitogen-activated protein kinases (MAPKs) extracellular signal-regulated kinase, p38 MAPK, and JNK (c-Jun N-terminal kinase) were activated in response to insulin, PD98059 (2'-amino-3'-methoxyflavone), an inhibitor of mitogen-activated protein kinase kinase, SP600125 (1,9-pyrazoloanthrone), an inhibitor of JNK, and SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole], an inhibitor of p38 MAPK, failed to inhibit the insulin-mediated increase in GCLC protein levels. In conclusion, these data show that insulin signaling pathways involving PI3K/Akt/p70S6K, but not MAPKs, are active in the insulin-mediated regulation of GSH synthesis via increased GCLC expression.
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Affiliation(s)
- Sang K Kim
- National Institute of Environmental Health Sciences, Wayne State University, 2727 Second Avenue, Room 4000, Detroit, MI 48201, USA
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Abdelmegeed MA, Kim SK, Woodcroft KJ, Novak RF. Acetoacetate activation of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase in primary cultured rat hepatocytes: role of oxidative stress. J Pharmacol Exp Ther 2004; 310:728-36. [PMID: 15051799 DOI: 10.1124/jpet.104.066522] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetes is characterized by elevated levels of ketone bodies acetoacetate (AA) and 3-hydroxybutyrate (3HB). High levels of ketone bodies have been implicated in generation of cellular oxidative stress. Ketone body activation of cellular signaling pathways associated with oxidative stress, however, has not been established. Thus, ketone body effects on kinase activation in primary cultured rat hepatocytes have been examined. Treatment with AA increased the phosphorylation of extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 mitogen-activated protein kinase (MAPK), maximally by approximately 2.5- and 4-fold, respectively. AA failed to activate c-Jun NH(2)-terminal kinase. AA-mediated Erk1/2 and p38 MAPK activation was detectable at 3 h post-treatment with maximal activation occurring at 12 h. In contrast, 3HB failed to activate any of these kinases. Elevated phosphorylation of Raf and MKK3/6 also occurred in response to AA. Bisindolylmaleimide, a generalized protein kinase C (PKC) inhibitor, and B581, a Ras farnesylation inhibitor, inhibited AA-mediated activation of Erk1/2 and p38 MAPK, suggesting a role for PKC and Ras in mediating such activation. Interestingly, the tyrosine kinase inhibitor genistein prevented the AA-mediated phosphorylation of Erk1/2, but not p38 MAPK. AA treatment resulted in the generation of reactive oxygen species (ROS) and the depletion of cellular glutathione levels, which was ameliorated by the antioxidants N-Acetyl-l-cysteine (NAC) and Trolox (6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid). NAC and Trolox also ameliorated AA-mediated Erk1/2 and p38 MAPK activation, suggesting that this activation is associated with ROS and oxidative stress.
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Affiliation(s)
- Mohamed A Abdelmegeed
- Institute of Environmental Health Sciences, Wayne State University, 2727 S Avenue, Rm 4000, Detroit, MI 48201, USA.
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Kim SK, Woodcroft KJ, Kim SG, Novak RF. Insulin and glucagon signaling in regulation of microsomal epoxide hydrolase expression in primary cultured rat hepatocytes. Drug Metab Dispos 2003; 31:1260-8. [PMID: 12975336 DOI: 10.1124/dmd.31.10.1260] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Microsomal epoxide hydrolase (mEH) plays an important role in the detoxification of a broad range of epoxide intermediates and has been reported to be decreased during diabetes and fasting. The signaling pathways involved in the regulation of mEH expression in response to insulin and glucagon were examined in primary cultured rat hepatocytes. mEH protein levels were increased 2- to 6-fold in hepatocytes cultured for 1 to 4 days, respectively, in the presence of insulin. Concentration-response studies revealed that insulin concentrations >or=1 nM resulted in increased mEH protein levels. The phosphatidylinositol 3-kinase (PI3K) inhibitors wortmannin or LY294002 [2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one], and rapamycin, an inhibitor of p70 S6 kinase phosphorylation, ameliorated the insulin-mediated increase in mEH protein levels. The p38 mitogen-activated protein (MAP) kinase inhibitors SB203580 and SB202190 also abrogated the insulin-mediated increase in mEH protein. Treatment of cells with glucagon, 8-bromo-cAMP, or dibutyryl-cAMP for 3 days resulted in decreased mEH protein levels. Pretreatment with the protein kinase A (PKA) inhibitor H89 (N-[2-(4-bromocinnamylamino)ethyl]-5-isoquinoline) prior to glucagon addition markedly attenuated the glucagon effect, implicating PKA signaling in the regulation of mEH expression. These data demonstrate that insulin and glucagon regulate, in an opposing manner, the expression of mEH in primary cultured rat hepatocytes. Furthermore, these data suggest that PI3K and p70 S6 kinase are active in the regulation of insulin-mediated mEH expression. We also provide data implicating p38 MAP kinase in the insulin-mediated increase in mEH levels. Moreover, cAMP and PKA are implicated in mediating the inhibitory effect of glucagon on mEH expression.
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Affiliation(s)
- Sang K Kim
- Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, USA
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Abstract
Mitochondrial dysfunction secondary to mitochondrial and nuclear DNA mutations has been associated with energy deficiency in multiple organ systems and a variety of severe, often fatal, clinical syndromes. Although the production of energy is indeed the primary function of mitochondria, attention has also been directed toward their role producing reactive oxygen and nitrogen species and the subsequent widespread deleterious effects of these intermediates. The generation of toxic reactive intermediates has been implicated in a number of relatively common disorders, including neurodegenerative diseases, diabetes, and cancer. Understanding the role mitochondrial dysfunction plays in the pathogenesis of common disorders has provided unique insights into a number of diseases and offers hope for potential new therapies.
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Affiliation(s)
- Gregory M Enns
- Department of Pediatrics, Division of Medical Genetics, Stanford University, 300 Pasteur Drive, H-315, Stanford, CA 94305-5208, USA.
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