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Yang ML, Connolly SE, Gee RJ, Lam TT, Kanyo J, Peng J, Guyer P, Syed F, Tse HM, Clarke SG, Clarke CF, James EA, Speake C, Evans-Molina C, Arvan P, Herold KC, Wen L, Mamula MJ. Carbonyl Posttranslational Modification Associated With Early-Onset Type 1 Diabetes Autoimmunity. Diabetes 2022; 71:1979-1993. [PMID: 35730902 PMCID: PMC9450849 DOI: 10.2337/db21-0989] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 06/15/2022] [Indexed: 11/13/2022]
Abstract
Inflammation and oxidative stress in pancreatic islets amplify the appearance of various posttranslational modifications to self-proteins. In this study, we identified a select group of carbonylated islet proteins arising before the onset of hyperglycemia in NOD mice. Of interest, we identified carbonyl modification of the prolyl-4-hydroxylase β subunit (P4Hb) that is responsible for proinsulin folding and trafficking as an autoantigen in both human and murine type 1 diabetes. We found that carbonylated P4Hb is amplified in stressed islets coincident with decreased glucose-stimulated insulin secretion and altered proinsulin-to-insulin ratios. Autoantibodies against P4Hb were detected in prediabetic NOD mice and in early human type 1 diabetes prior to the onset of anti-insulin autoimmunity. Moreover, we identify autoreactive CD4+ T-cell responses toward carbonyl-P4Hb epitopes in the circulation of patients with type 1 diabetes. Our studies provide mechanistic insight into the pathways of proinsulin metabolism and in creating autoantigenic forms of insulin in type 1 diabetes.
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Affiliation(s)
- Mei-Ling Yang
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Sean E. Connolly
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Renelle J. Gee
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
| | - TuKiet T. Lam
- Mass Spectrometry & Proteomics Resource, W.M. Keck Foundation Biotechnology Resource Laboratory, New Haven
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Jean Kanyo
- Mass Spectrometry & Proteomics Resource, W.M. Keck Foundation Biotechnology Resource Laboratory, New Haven
| | - Jian Peng
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Perrin Guyer
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Farooq Syed
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Hubert M. Tse
- Department of Microbiology, Comprehensive Diabetes Center, University of Alabama at Birmingham, Birmingham, AL
| | - Steven G. Clarke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA
| | - Catherine F. Clarke
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA
| | - Eddie A. James
- Center for Translational Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Cate Speake
- Center for Interventional Immunology, Benaroya Research Institute at Virginia Mason, Seattle, WA
| | - Carmella Evans-Molina
- Center for Diabetes and Metabolic Diseases, Indiana University School of Medicine, Indianapolis, IN
| | - Peter Arvan
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Kevan C. Herold
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
- Department of Immunobiology, Yale University, New Haven, CT
| | - Li Wen
- Section of Endocrinology, Department of Internal Medicine, Yale University, New Haven, CT
| | - Mark J. Mamula
- Section of Rheumatology, Allergy and Immunology, Department of Internal Medicine, Yale University, New Haven, CT
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Mizobuchi M, Ishidoh K, Kamemura N. A comparison of cell death mechanisms of antioxidants, butylated hydroxyanisole and butylated hydroxytoluene. Drug Chem Toxicol 2021; 45:1899-1906. [PMID: 34013795 DOI: 10.1080/01480545.2021.1894701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Butylated hydroxyanisole (BHA) and the chemically similar butylated hydroxytoluene (BHT) are widely used as antioxidants. Toxicity of BHA and BHT has been reported under in vitro and in vivo experimental conditions. However, the mechanism of BHA-induced toxic effects in cells is unclear. In this study, the cytotoxic effects of BHA and differences in cell death mechanism for BHA and BHT were investigated in rat thymocytes by flow cytometric analysis using a fluorescent probe. We observed a significant increase in propidium iodide fluorescence in the population of cells treated with 100 μM and 300 μM BHA (dead cells). Thymocytes treated with 100 µM BHA showed increased intracellular Ca2+ and Zn2+ levels and depolarized cell membranes. BHA (30-100 µM) decreased non-protein thiol content of cells, indicating decreased glutathione content. Co-stimulation with 100 µM BHA and 300 µM H2O2 acted synergistically to increase cell lethality. Moreover, BHA significantly increased caspase-3 activity and the number of annexin-V-positive cells in a concentration-dependent manner, indicating apoptosis. However, BHT reduced caspase-3 activity and increased the number of annexin-V-negative dead cells, indicating non-apoptotic cell death. Our results reveal the toxicity of BHA could be attributed to increased levels of intracellular Ca2+ and Zn2+, resulting in an increased vulnerability of rat thymocytes to oxidative stress. In addition, we demonstrate that whereas BHA induced apoptosis, BHT induced non-apoptotic cell death in rat thymocytes. Therefore, these results may support the safety of BHA, but also demonstrate the importance of performing toxicity evaluation at the cellular level besides the tissue level.
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Affiliation(s)
- Mizuki Mizobuchi
- Department of Food-Nutrition Sciences, Faculty of Life Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Kazumi Ishidoh
- Department of Food-Nutrition Sciences, Faculty of Life Sciences, Tokushima Bunri University, Tokushima, Japan
| | - Norio Kamemura
- Department of Food-Nutrition Sciences, Faculty of Life Sciences, Tokushima Bunri University, Tokushima, Japan
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Reinoso Webb C, den Bakker H, Koboziev I, Jones-Hall Y, Rao Kottapalli K, Ostanin D, Furr KL, Mu Q, Luo XM, Grisham MB. Differential Susceptibility to T Cell-Induced Colitis in Mice: Role of the Intestinal Microbiota. Inflamm Bowel Dis 2018; 24:361-379. [PMID: 29361089 PMCID: PMC6176899 DOI: 10.1093/ibd/izx014] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Indexed: 12/12/2022]
Abstract
One of the best characterized mouse models of the inflammatory bowel diseases (IBD; Crohn's disease, ulcerative colitis) is the CD4+CD45RBhigh T cell transfer model of chronic colitis. Following our relocation to Texas Tech University Health Sciences Center (TTUHSC), we observed a dramatic reduction in the incidence of moderate-to-severe colitis from a 16-year historical average of 90% at Louisiana State University Health Sciences Center (LSUHSC) to <30% at TTUHSC. We hypothesized that differences in the commensal microbiota at the 2 institutions may account for the differences in susceptibility to T cell-induced colitis. Using bioinformatic analyses of 16S rRNA amplicon sequence data, we quantified and compared the major microbial populations in feces from healthy and colitic mice housed at the 2 institutions. We found that the bacterial composition differed greatly between mice housed at LSUHSC vs TTUHSC. We identified several genera strongly associated with, and signficantly overrepresented in high responding RAG-/- mice housed at LSUHSC. In addition, we found that colonization of healthy TTUHSC RAG-/- mice with feces obtained from healthy or colitic RAG-/- mice housed at LSUHSC transferred susceptibility to T cell-induced colitis such that the recipients developed chronic colitis with incidence and severity similar to mice generated at LSUHSC. Finally, we found that the treatment of mice with preexisting colitis with antibiotics remarkably attenuated disease. Taken together, our data demonstrate that specific microbial communities determine disease susceptibility and that manipulation of the intestinal microbiota alters the induction and/or perpetuation of chronic colitis.
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Affiliation(s)
- Cynthia Reinoso Webb
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX
| | | | - Iurii Koboziev
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Yava Jones-Hall
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, West Lafayette, IN
| | | | - Dmitry Ostanin
- Immunology Discovery, Translational Research and Development, Bristol Myers Squibb, Princeton, NJ
| | - Kathryn L Furr
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Qinghui Mu
- Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA
| | - Xin M Luo
- Department of Biomedical Sciences and Pathobiology, College of Veterinary Medicine, Virginia Tech, Blacksburg, VA
| | - Matthew B Grisham
- Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, Lubbock, TX,Correspondence address. Department of Immunology and Molecular Microbiology, Texas Tech University Health Sciences Center, 3601 4th Street STOP 6591, Lubbock, Texas 79430-6591. E-mail:
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Wong JC, Vo V, Gorjala P, Fiscus RR. Pancreatic-β-cell survival and proliferation are promoted by protein kinase G type Iα and downstream regulation of AKT/FOXO1. Diab Vasc Dis Res 2017. [PMID: 28631500 DOI: 10.1177/1479164117713947] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Early studies showed nitric oxide as a pro-inflammatory-cytokine-induced toxin involved in pancreatic β-cell destruction during pathogenesis of type-1 diabetes. However, nitric oxide has both cytotoxic and cytoprotective effects on mammalian cells, depending on concentration and micro-environmental surroundings. Our studies have shown that low/physiological-level nitric oxide selectively activates protein kinase G type Iα isoform, promoting cytoprotective/pro-cell-survival effects in many cell types. In bone marrow-derived stromal/mesenchymal stem cells, protein kinase G type Iα mediates autocrine effects of nitric oxide and atrial natriuretic peptide, promoting DNA-synthesis/proliferation and cell survival. In this study, endothelial nitric oxide synthase/neuronal nitric oxide synthase inhibitor L-NIO (L-N(5)-(1-iminoethyl)ornithine), soluble guanylyl cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3,-a] quinoxalin-1-one), atrial natriuretic peptide-receptor inhibitor A71915 and protein kinase G type Iα kinase activity inhibitor DT-2 all increased apoptosis and decreased insulin secretion in RINm5F pancreatic β-cells, suggesting autocrine regulatory role for endogenous nitric oxide- and atrial natriuretic peptide-induced activation of protein kinase G type Iα. In four pancreatic β-cell lines, Beta-TC-6, RINm5F, INS-1 and 1.1B4, protein kinase G type Iα small-interfering RNA decreased phospho-serine-239-VASP (indicator of endogenous protein kinase G type Iα kinase activity), increased apoptosis and decreased proliferation. In protein kinase G type Iα-knockdown β-cell lines, expressions of phospho-protein kinase B (PKB/AKT) (AKT), phospho-Forkhead box protein O1 (FOXO1) (transcriptional repressor of pancreas duodenum homobox-1) and pancreas duodenum homobox-1 were decreased, suppressing proliferation and survival in pancreatic β-cells. The data suggest autocrine nitric oxide/atrial natriuretic peptide-induced activation of protein kinase G type Iα/p-AKT/p-FOXO1 promotes survival and proliferation in pancreatic β-cells, providing therapeutic implications for development of new therapeutic agents for diabetes.
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Affiliation(s)
- Janica C Wong
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Van Vo
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Priyatham Gorjala
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
| | - Ronald R Fiscus
- 1 Department of Biomedical Sciences, College of Medicine, Roseman University of Health Sciences, Las Vegas, NV, USA
- 2 Pharmaceutical Sciences, College of Pharmacy, Roseman University of Health Sciences, Henderson, NV, USA
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Pyrrolidine dithiocarbamate ameliorates endothelial dysfunction in thoracic aorta of diabetic rats by preserving vascular DDAH activity. PLoS One 2017; 12:e0179908. [PMID: 28715444 PMCID: PMC5513417 DOI: 10.1371/journal.pone.0179908] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/07/2017] [Indexed: 01/27/2023] Open
Abstract
Objective Endothelial dysfunction plays a pivotal role in the development of diabetic cardiovascular complications. Accumulation of endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) and inhibition of dimethylarginine dimethylaminohydrolase (DDAH) activity have been involved in diabetic endothelial dysfunction. This study was to investigate the effect of pyrrolidine dithiocarbamate (PDTC) on impairment of endothelium-dependent vasodilatation in diabetic rats and its potential mechanism. Methods Diabetic rats were induced by a single intraperitoneal injection of streptozotocin (60mg/kg), and PDTC (10mg/kg) was given in drinking water for 8 weeks. Blood glucose and serum ADMA concentrations were measured in experimental rats. Recombinant adenovirus encoding human DDAH2 gene were constructed and ex vivo transferred to isolated rat aortas. The maximal relaxation (Emax) and half maximal effective concentration (EC50) of aortic rings response to accumulative concentrations of acetylcholine and vascular DDAH activity were examined before and after gene transfection. Results Diabetic rats displayed significant elevations of blood glucose and serum ADMA levels compared to control group (P<0.01). Vascular DDAH activity and endothelium-dependent relaxation of aortas were inhibited, as expressed by the decreased Emax and increased EC50 in diabetic rats compared to control rats (P<0.01). Treatment with PDTC not only decreased blood glucose and serum ADMA concentration (P<0.01) but also restored vascular DDAH activity and endothelium-dependent relaxation, evidenced by the higher Emax and lower EC50 in PDTC-treated diabetic rats compared to untreated diabetic rats (P<0.01). Similar restoration of Emax, EC50 and DDAH activity were observed in diabetic aortas after DDAH2-gene transfection. Conclusions These results indicate that PDTC could ameliorate impairment of endothelium-dependent relaxation in diabetic rats. The underlying mechanisms might be related to preservation of vascular DDAH activity and consequent reduction of endogenous ADMA in endothelium via its antioxidant action. This study highlights the therapeutic potential of PDTC in impaired vasodilation and provides a new strategy for treatment of diabetic cardiovascular complications.
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de Souza Bastos A, Graves DT, de Melo Loureiro AP, Júnior CR, Corbi SCT, Frizzera F, Scarel-Caminaga RM, Câmara NO, Andriankaja OM, Hiyane MI, Orrico SRP. Diabetes and increased lipid peroxidation are associated with systemic inflammation even in well-controlled patients. J Diabetes Complications 2016; 30:1593-1599. [PMID: 27497685 PMCID: PMC5120401 DOI: 10.1016/j.jdiacomp.2016.07.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 07/09/2016] [Accepted: 07/13/2016] [Indexed: 12/21/2022]
Abstract
BACKGROUND The effect of the interaction between type 2 diabetes and dyslipidemia on inflammation and lipid peroxidation (LPO) has not been assessed. AIM To investigate whether diabetes coupled with dyslipidemia alters oxidative metabolism leading to increased LPO products and inflammatory status. METHODS 100 patients were divided into four groups based upon diabetic and dyslipidemic status: poorly controlled diabetes with dyslipidemia (DM-PC/D), well-controlled diabetes with dyslipidemia (DM-WC/D), normoglycemic individuals with dyslipidemia (NG/D), and normoglycemic individuals without dyslipidemia (NG/ND). Plasma was evaluated for an LPO product (MDA), antioxidant levels and inflammatory cytokines. RESULTS Diabetics presented significantly higher levels of LPO (p<0.05) and the DM-PC/D had higher levels of proinflammatory cytokines and MDA in the plasma in comparison with normoglycemics (p<0.05). Interestingly IL1-β, IL-6, and TNF-α in DM-WC/D were not statistically different from those in DM-PC/D. Normoglycemic individuals with dyslipidemia presented significantly increased levels of IL-6 and TNF-α when compared to normoglycemic without dyslipidemia (p<0.05). MDA levels were also positively correlated with the presence of DM complications (r=0.42, p<0.01). CONCLUSIONS These findings show that dyslipidemia is associated with an increased inflammatory status, even in well-controlled diabetics and in normoglycemics. Our results suggest that lipid metabolism and peroxidation are important for the development of inflammation, which is elevated in several complications associated with diabetes.
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Affiliation(s)
- Alliny de Souza Bastos
- Department of Diagnosis and Surgery, Araraquara School of Dentistry UNESP-Univ Estadual Paulista, Araraquara, São Paulo, Brazil.
| | - Dana T Graves
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ana Paula de Melo Loureiro
- Department of Clinical and Toxicological Analyses, Faculty of Pharmaceutical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Carlos Rossa Júnior
- Department of Diagnosis and Surgery, Araraquara School of Dentistry UNESP-Univ Estadual Paulista, Araraquara, São Paulo, Brazil
| | - Sâmia Cruz Tfaile Corbi
- Department of Morphology, School of Dentistry at Araraquara, UNESP-Univ Estadual Paulista, Araraquara, SP, Brazil
| | - Fausto Frizzera
- Faculdades Integradas Espírito Santenses-FAESA Dental School, Vitoria, Espírito Santo (ES)
| | | | - Niels Olsen Câmara
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Oelisoa M Andriankaja
- Center for Clinical Research and Health Promotion, School of Dental Medicine, University of Puerto Rico
| | - Meire I Hiyane
- Department of Immunology, Institute of Biomedical Sciences, University of São Paulo (USP), São Paulo, Brazil
| | - Silvana Regina Perez Orrico
- Department of Diagnosis and Surgery, Araraquara School of Dentistry UNESP-Univ Estadual Paulista, Araraquara, São Paulo, Brazil
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Effect of dietary antioxidant supplementation (Cuminum cyminum) on bacterial susceptibility of diabetes-induced rats. Cent Eur J Immunol 2016; 41:132-7. [PMID: 27536197 PMCID: PMC4967646 DOI: 10.5114/ceji.2016.60985] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 11/23/2015] [Indexed: 12/24/2022] Open
Abstract
Diabetic patients are at risk of acquiring infections. Chronic low-grade inflammation is an important factor in the pathogenesis of diabetic complication. Diabetes causes generation of reactive oxygen species that increases oxidative stress, which may play a role in the development of complications as immune-deficiency and bacterial infection. The study aimed to investigate the role of a natural antioxidant, cumin, in the improvement of immune functions in diabetes. Diabetes was achieved by interperitoneal injection of streptozotocin (STZ). Bacterial infection was induced by application of Staphylococcus aureus suspension to a wound in the back of rats. The antioxidant was administered for 6 weeks. Results revealed a decrease in blood glucose levels in diabetic rats (p < 0.001), in addition to improving immune functions by decreasing total IgE approaching to the normal control level. Also, inflammatory cytokine (IL-6, IL-1β and TNF) levels, as well as total blood count decreased in diabetic rats as compared to the control group. Thus, cumin may serve as anti-diabetic treatment and may help in attenuating diabetic complications by improving immune functions. Therefore, a medical dietary antioxidant supplementation is important to improve the immune functions in diabetes.
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Ding H, Zhu T, Yin X, Liu J, Zhang L, Bernier M, Zhao R. Pyrrolidine dithiocarbamate protects pancreatic β-cells from oxidative damage through regulation of FoxO1 activity in type 2 diabetes rats. Acta Biochim Biophys Sin (Shanghai) 2014; 46:582-9. [PMID: 24829401 DOI: 10.1093/abbs/gmu034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pyrrolidine dithiocarbamate (PDTC) can lower the blood glucose level and improve the insulin sensitivity in diabetic rats. However, the mechanisms underlying this effect of PDTC treatment in diabetic rats remained uncertain. In this study, we evaluated the mechanisms by which PDTC conferred protection against oxidative damage to pancreatic islet β-cells in rats with experimental type 2 diabetes mellitus (DM). DM in the rats was elicited by long-term high-fat diet accompanied with a single intraperitoneal (i.p.) injection of a low dose of streptozotocin. After a 7-day administration of PDTC (50 mg/kg/day i.p.), blood glucose levels were measured and pancreatic tissues were collected for the determination of various biochemical and enzymatic activities using immunohistochemistry, immunofluorescence, and western blot techniques. The percentage of apoptotic pancreatic islet β-cells was detected by flow cytometry. The results showed that diabetic rats had elevated blood glucose levels and insulin resistance, accompanied with an increase in malondialdehyde content, nitrotyrosine production, and inducible nitric oxide synthase expression. A decrease in superoxide dismutase and glutathione peroxidase activities was also observed in DM rats, culminating with elevated β-cell apoptosis. PDTC treatment significantly reduced the oxidative damage and the β-cell apoptosis, and also increased the insulin production through down-regulating FoxO1 acetylation and up-regulating nuclear PDX-1 level. These data suggested that PDTC can protect islet β-cells from oxidative damage and improve insulin production through regulation of PDX-1 and FoxO1 in a DM rat model.
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Affiliation(s)
- Haiyan Ding
- Department of Endocrinology, Fourth Hospital, Hebei Medical University, Shijiazhuang 050011, China
| | - Tienian Zhu
- Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Department of Immunology, Hebei Medical University, Shijiazhuang 050017, China Department of Medical Oncology, Bethune International Peace Hospital, Shijiazhuang 050082, China
| | - Xiaomei Yin
- Department of Medical Oncology, Bethune International Peace Hospital, Shijiazhuang 050082, China
| | - Jiankun Liu
- Department of Medical Oncology, Bethune International Peace Hospital, Shijiazhuang 050082, China
| | - Lizhong Zhang
- Department of Medical Oncology, Bethune International Peace Hospital, Shijiazhuang 050082, China
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Ruijing Zhao
- Key Laboratory of Immune Mechanism and Intervention on Serious Disease in Hebei Province, Department of Immunology, Hebei Medical University, Shijiazhuang 050017, China
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Delmastro-Greenwood MM, Tse HM, Piganelli JD. Effects of metalloporphyrins on reducing inflammation and autoimmunity. Antioxid Redox Signal 2014; 20:2465-77. [PMID: 23472672 DOI: 10.1089/ars.2013.5257] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE High levels of reactive oxygen species can facilitate DNA and protein damage beyond the control of endogenous antioxidants, resulting in oxidative stress. Oxidative stress then triggers inflammation, which can lead to pathological conditions. In genetically susceptible individuals, the conglomeration of oxidative stress and inflammation can enhance autoreactive immune cell activation, causing beta-cell destruction in autoimmune type 1 diabetes. As a means of shielding pancreatic islets, manganese porphyrin (MnP) oxidoreductant treatment has been tested in a number of reported studies. RECENT ADVANCES MnP affects both innate and adaptive immune cell responses, blocking nuclear factor kappa-B activation, proinflammatory cytokine secretion, and T helper 1 T-cell responses. As a result, MnP treatment protects against type 1 diabetes onset in nonobese diabetic mice and stabilizes islets for cellular transplantation. CRITICAL ISSUES MnP displays global immunosuppressive properties, exemplified by decreased cytokine production from all T-helper cell subsets. This quality may impact infection control in the setting of autoimmunity. Nonetheless, because of their cytoprotective and immunomodulatory function, MnPs should be considered as a safer alternative to other clinical immunosuppressive agents (i.e., rapamycin) for transplantation. FUTURE DIRECTIONS Although MnP likely affects only redox-sensitive targets, the mechanism behind global T-cell immunosuppression and the outcome on infection clearance will have to be elucidated. Based on the increased primary engraftment seen with MnP use, protection against primary nonfunction in porcine to human xenotransplants would likely be enhanced. Further, a better understanding of MnP oxidoreductase function may allow for its use in other chronic inflammatory conditions.
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Affiliation(s)
- Meghan M Delmastro-Greenwood
- 1 Division of Immunogenetics, Department of Pediatrics, Rangos Research Center, Diabetes Institute , Children's Hospital of Pittsburgh of UPMC, Pittsburgh, Pennsylvania
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Hadi NR, Al-Amran F, Hussein MAA, Rezeg FA. Evaluation of the effects of glimepiride (Amaryl) and repaglinide (novoNorm) on atherosclerosis progression in high cholesterol-fed male rabbits. J Cardiovasc Dis Res 2012; 3:5-11. [PMID: 22346138 PMCID: PMC3271684 DOI: 10.4103/0975-3583.91592] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Atherosclerosis is an inflammatory disease of the blood vessel wall, characterized in early stages by endothelial dysfunction, recruitment and activation of monocyte/macrophages. Glimepiride is one of the third generation sulphonylurea drugs, useful for control of diabetes mellitus type two and it may exert anti inflammatory activity, by induction of nitric oxide production or through selective suppression of the cyclooxygenase pathway. Repaglinide is a new hypoglycemic agent, and a member of the carbamoylmethyl benzoic acid family. Some results from the literature demonstrate that repaglinide has favorable effects on the parameters of antioxidative balance. OBJECTIVES The objective of the present study was to assess the effect of glimepiride and repaglinide on atherosclerosis via interfering with the inflammatory and oxidative pathways. MATERIALS AND METHODS Twenty four local domestic male rabbits were involved in this study. The animals were randomly divided into four groups; Group I rabbits fed normal chow (oxiod) diet for 10 weeks. Group II rabbits were fed with 1% cholesterol enriched diet. Group III rabbits were fed with 1% cholesterol enriched diet together with Glimepiride (0.1 mg/kg once daily before morning feed). Group IV rabbits were fed with 1% cholesterol enriched diet together with Repaglinide (0.3 mg/kg once daily before morning feed). Blood samples were collected before (0 time) and every two weeks of experimental diets for measurement of serum triglycerides (TG), total cholesterol (TC), High-density lipoprotein cholesterol (HDL-C), high sensitive C - reactive protein (hsCRP), Interleukin - 6 (IL-6) and Tumor Necrosis Factor alpha (TNF-α) levels. At the end of 10 weeks, the aorta was removed for measurement of aortic Malondialdehyde (MDA), reduced glutathione (GSH) and aortic intimal thickness. RESULTS Glimepiride and repaglinide treatment did show significant effect on lipid parameters compared with induced untreated group (P < 0.05). Also, they significantly reduced the elevation in hsCRP, IL-6, TNF-α, aortic MDA and aortic intimal thickness compared with induced untreated group (P < 0.05), and they helped to restore the aortic GSH levels (P < 0.05). CONCLUSIONS Glimepiride and repaglinide may reduce atherosclerosis progression in hypercholesterolemic rabbits by interfering with the inflammatory and oxidative pathways without affecting lipid parameters.
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Affiliation(s)
- Najah R Hadi
- Department of Pharmacology, Medical College Kufa University, Najaf, Iraq
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Zhu T, Zhao R, Zhang L, Bernier M, Liu J. Pyrrolidine dithiocarbamate enhances hepatic glycogen synthesis and reduces FoxO1-mediated gene transcription in type 2 diabetic rats. Am J Physiol Endocrinol Metab 2012; 302:E409-16. [PMID: 22127228 PMCID: PMC3774491 DOI: 10.1152/ajpendo.00453.2011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The aim of the present study was to examine the effects of pyrrolidine dithiocarbamate (PDTC) on hepatic glycogen synthesis and FoxO1 transcriptional activity in type 2 diabetic rats and the mechanism underlying these effects. Fasting blood glucose and glycogen deposition, together with expressions of two key genes related to gluconeogenesis, were studied in the liver of rats fed a normal diet (NC), high-fat diet (HFD)-induced insulin-resistant rats made type 2 diabetic by a single intraperitoneal injection of streptozotocin (DM), and a DM with intervention of PDTC (DM + PDTC) for 1 wk. The phosphorylation of Akt, GSK-3β, and FoxO1 was assessed in liver extracts of fasted rats by Western blot, whereas indirect immunofluorescence staining was performed to determine the cellular distribution of FoxO1. The DM rats exhibited obvious increases in fasting blood glucose as well as decreased hepatic glycogen content compared with the NC group. Activation of the Akt/GSK-3β pathway and inactivating phosphorylation of FoxO1 were reduced greatly in DM rat livers (P < 0.01). By contrast, PDTC treatment protected DM rats against high fasting blood glucose and hepatic glycogen deposition loss. PDTC also elicited an increase in Akt/GSK-3β signaling and subsequent inactivation and nuclear export of FoxO1 in DM rat livers, which translated into a significant reduction in the expression of two FoxO1 target genes, phosphoenolpyruvate carboxykinase and glucose-6-phosphatase. This study suggests that PDTC enhances hepatic glycogen synthesis, whereas it reduces FoxO1 transcriptional activity in DM rats.
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Affiliation(s)
- Tienian Zhu
- Department of Medical Oncology, Bethune International Peace Hospital, Shijiazhuang, China
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12
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Oxidative stress and redox modulation potential in type 1 diabetes. Clin Dev Immunol 2011; 2011:593863. [PMID: 21647409 PMCID: PMC3102468 DOI: 10.1155/2011/593863] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 03/09/2011] [Indexed: 12/21/2022]
Abstract
Redox reactions are imperative to preserving cellular metabolism yet must be strictly regulated. Imbalances between reactive oxygen species (ROS) and antioxidants can initiate oxidative stress, which without proper resolve, can manifest into disease. In type 1 diabetes (T1D), T-cell-mediated autoimmune destruction of pancreatic β-cells is secondary to the primary invasion of macrophages and dendritic cells (DCs) into the islets. Macrophages/DCs, however, are activated by intercellular ROS from resident pancreatic phagocytes and intracellular ROS formed after receptor-ligand interactions via redox-dependent transcription factors such as NF-κB. Activated macrophages/DCs ferry β-cell antigens specifically to pancreatic lymph nodes, where they trigger reactive T cells through synapse formation and secretion of proinflammatory cytokines and more ROS. ROS generation, therefore, is pivotal in formulating both innate and adaptive immune responses accountable for islet cell autoimmunity. The importance of ROS/oxidative stress as well as potential for redox modulation in the context of T1D will be discussed.
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Chen N, Leng YP, Xu WJ, Luo JD, Chen MS, Xiong Y. Contribution of endogenous inhibitor of nitric oxide synthase to hepatic mitochondrial dysfunction in streptozotocin-induced diabetic rats. Cell Physiol Biochem 2011; 27:341-52. [PMID: 21471723 DOI: 10.1159/000327960] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2011] [Indexed: 11/19/2022] Open
Abstract
AIMS Mitochondrial dysfunction plays important roles in the development of diabetes. Elevated nitric oxide (NO) synthase inhibitor asymmetric dimethylarginine (ADMA) has been shown to be closely related to diabetes. But the relationship between them in diabetes has not been determined. This study was to explore the role of ADMA in hepatic mitochondrial dysfunction and its potential mechanisms in diabetic rats and hepatocytes. METHODS Respiratory enzymes activities, mitochondrial transmembrane potential and ATP content were measured to evaluate mitochondrial function. The copy number ratio of mitochondrial gene to nuclear gene was used to represent mitochondrial biogenesis. The activity of superoxide dismutase and malondialdehyde content were detected to reflect oxidative stress. Furthermore, changes in ADMA and NO contents, uncoupling protein 2 (UCP2) and peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) transcriptions were determined. RESULTS Elevated ADMA levels in serum of diabetic rats were found to be associated with hepatic mitochondrial dysfunction reflected by reductions of respiratory enzyme activities, mitochondrial membrane potential and ATP contents. Similar mitochondrial dysfunction also occurred in ADMA-treated hepatocytes. The mitochondrial dysfunction observed in diabetic rats or hepatocytes was accompanied with suppressions of mitochondrial biogenesis, PGC-1α transcription and NO synthesis as well as enhances of UCP 2 transcription and oxidative stress. These effects of ADMA could be attenuated by treatments with antioxidant or NO donor. CONCLUSIONS These results indicate that elevated endogenous ADMA contributes to hepatic mitochondrial dysfunction in diabetic rats, and underlying mechanisms may be related to the suppression of mitochondrial biogenesis and mitochondrial uncoupling via inhibiting NO synthesis and enhancing oxidative stress.
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Affiliation(s)
- Na Chen
- Department of Pharmacology, Guangzhou Medical University, Guangzhou, PR China
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14
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Machida K, Tsukamoto H, Liu JC, Han YP, Govindarajan S, Lai MMC, Akira S, Ou JHJ. c-Jun mediates hepatitis C virus hepatocarcinogenesis through signal transducer and activator of transcription 3 and nitric oxide-dependent impairment of oxidative DNA repair. Hepatology 2010; 52:480-92. [PMID: 20683948 PMCID: PMC3107125 DOI: 10.1002/hep.23697] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
UNLABELLED Hepatocellular carcinoma (HCC) occurs in a significant number of patients with hepatitis C virus (HCV) infection. HCV causes double-strand DNA breaks and enhances the mutation frequency of proto-oncogenes and tumor suppressors. However, the underlying mechanisms for these oncogenic events are still elusive. Here, we studied the role of c-Jun, signal transducer and activator of transcription 3 (STAT3), and nitric oxide (NO) in spontaneous and diethylnitrosamine (DEN)-initiated and/or phenobarbital (Pb)-promoted HCC development using HCV core transgenic (Tg) mice. The viral core protein induces hepatocarcinogenesis induction as a tumor initiator under promotion by Pb treatment alone. Conditional knockout of c-jun and stat3 in hepatocytes achieves a nearly complete, additive effect on prevention of core-induced spontaneous HCC or core-enhanced HCC incidence caused by DEN/Pb. Core protein induces hepatocyte proliferation and the expression of inflammatory cytokines (interleukin-6, tumor necrosis factor-alpha, interleukin-1) and inducible NO synthase (iNOS); the former is dependent on c-Jun and STAT3, and the latter on c-Jun. Oxidative DNA damage repair activity is impaired by the HCV core protein due to reduced DNA glycosylase activity for the excision of 8-oxo-2'-deoxyguanosine. This impairment is abrogated by iNOS inhibition or c-Jun deficiency, but aggravated by the NO donor or iNOS-inducing cytokines. The core protein also suppresses apoptosis mediated by Fas ligand because of c-Jun-dependent Fas down-regulation. CONCLUSION These results indicate that the HCV core protein potentiates chemically induced HCC through c-Jun and STAT3 activation, which in turn, enhances cell proliferation, suppresses apoptosis, and impairs oxidative DNA damage repair, leading to hepatocellular transformation.
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Affiliation(s)
- Keigo Machida
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA.
| | - Hidekazu Tsukamoto
- Department of Pathology, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033, Southern California Research Center for ALPD and Cirrhosis, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033, Department of Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, USA
| | - Jian-Chang Liu
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033
| | - Yuan-Ping Han
- Department of Surgery, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033
| | - Sugantha Govindarajan
- Department of Pathology, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033, Southern California Research Center for ALPD and Cirrhosis, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033
| | - Michael M. C. Lai
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033, National Chun Kung University, Tainan, Taiwan
| | | | - Jing-hsiung James Ou
- Department of Molecular Microbiology and Immunology, University of Southern California, Keck School of Medicine, 2011 Zonal Avenue, Los Angeles, California, 90033
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Gumieniczek A, Hopkała H, Roliński J, Bojarska-Junak A. Interleukin-6 and Oxidative Stress in Plasma of Alloxan-Induced Diabetic Rabbits after Pioglitazone Treatment. Immunopharmacol Immunotoxicol 2008; 28:81-91. [PMID: 16684669 DOI: 10.1080/08923970600625785] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
There is evidence that oxidative stress might be implicated in promoting a state of systemic inflammation in diabetic patients. Understanding the role of reactive oxygen species in the inflammatory response in diabetes becomes essential in finding preventive treatments. Pioglitazone is a new oral antidiabetic agent with potent antioxidant and anti-inflammatory properties. The drug is a high affinity ligand of peroxisome proliferator-activated receptor gamma. This receptor seems to be involved in the control of inflammation by modulating the production of inflammatory mediators. In the present study, the changes in some markers of enhanced oxidative stress and in the level of pro-inflammatory interleukin-6 (IL-6) were examined in plasma of diabetic rabbits after 4 and 8 weeks of pioglitazone treatment. Ascorbic acid (AA) concentration and total antioxidant status (TAS) in plasma of diabetic animals were diminished and significantly elevated after pioglitazone treatment (p < 0.05). Protein carbonyl groups (PCG) content and IL-6 concentration were elevated in plasma of diabetic animals and significantly diminished after pioglitazone treatment. The results obtained in the present study confirm the relations of cytokine systems with oxidative stress in plasma of diabetic subjects. They also suggest the antioxidative and antinflammatory properties of pioglitazone.
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Affiliation(s)
- A Gumieniczek
- Department of Medicinal Chemistry, Medical University of Lublin, Poland.
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Graves DT, Kayal RA. Diabetic complications and dysregulated innate immunity. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 2008; 13:1227-39. [PMID: 17981625 PMCID: PMC3130196 DOI: 10.2741/2757] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Diabetes mellitus is a metabolic disorder that leads to the development of a number of complications. The etiology of each diabetic complication is undoubtedly multifactorial. We will focus on one potential component that may be common in many diabetic complications, dysregulation of innate immunity associated with an increased inflammatory response. High glucose levels lead to shunting through the polyol pathway, an increase in diacylglycerol which activates protein kinase C, an increase in the release of electrons that react with oxygen molecules to form superoxides, and the non-enzymatic glycosylation of proteins that result in greater formation of advanced glycation end products. Each of these can lead to aberrant cell signalling that affects innate immunity for example, by activating the MAP kinase pathway or inducing activation of transcription factors such as NF-kappaB. This may be a common feature of several complications including periodontal disease, atherosclerosis, nephropathy, impaired healing and retinopathy. These complications are frequently associated with increased expression of inflammatory cytokines such as TNF-alpha, IL-1beta and IL-6 and enhanced generation of reactive oxygen species. Cause and effect relationship between dysregulation of key components of innate immunity and diabetic complications in many instances have been demonstrated with the use of cytokine blockers and antioxidants.
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Affiliation(s)
- Dana T Graves
- Boston University School of Dental Medicine, Department of Periodontology and Oral Biology, W-202D, 700 Albany Street, Boston, MA 02118, USA.
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Stosic-Grujicic S, Cvetkovic I, Mangano K, Fresta M, Maksimovic-Ivanic D, Harhaji L, Popadic D, Momcilovic M, Miljkovic D, Kim J, Al-Abed Y, Abed YA, Nicoletti F. A potent immunomodulatory compound, (S,R)-3-Phenyl-4,5-dihydro-5-isoxazole acetic acid, prevents spontaneous and accelerated forms of autoimmune diabetes in NOD mice and inhibits the immunoinflammatory diabetes induced by multiple low doses of streptozotocin in CBA/H mice. J Pharmacol Exp Ther 2006; 320:1038-49. [PMID: 17148780 DOI: 10.1124/jpet.106.109272] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
(S,R)-3-Phenyl-4,5-dihydro-5-isoxasole acetic acid (VGX-1027) is an isoxazole compound that exhibits various immunomodulatory properties. The capacity of VGX-1027 to prevent interleukin (IL)-1beta plus interferon-gamma-induced pancreatic islet death in vitro prompted us to evaluate its effects on the development of autoimmune diabetes in preclinical models of human type 1 diabetes mellitus (T1D). Administration of VGX-1027 to NOD mice with spontaneous or accelerated forms of diabetes induced either by injection of cyclophosphamide or by transfer of spleen cells from acutely diabetic syngeneic donors markedly reduced the cumulative incidence of diabetes and insulitis. In addition, VGX-1027 given either i.p. or p.o. to CBA/H mice made diabetic with multiple low doses of streptozotocin successfully counteracted the development of destructive insulitis and hyperglycemia. The animals receiving VGX-1027 exhibited reduced production of the proinflammatory mediators tumor necrosis factor-alpha, IL-1beta, macrophage migration inhibitory factor, and inducible nitric-oxide synthase-mediated nitric oxide generation in both pancreatic islets and peripheral compartments. These results indicate that VGX-1027 probably exerts its antidiabetogenic effects by limiting cytokine-mediated immunoinflammatory events, leading to inflammation and destruction of pancreatic islets. VGX-1027 seems worthy of being considered as a candidate drug in the development of new therapeutic strategies for the prevention and early treatment of T1D.
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MESH Headings
- Acetates/chemistry
- Acetates/pharmacokinetics
- Acetates/therapeutic use
- Animals
- Cell Line, Tumor
- Cell Survival/drug effects
- Chromatography, High Pressure Liquid
- Cyclophosphamide/pharmacology
- Cytokines/immunology
- Diabetes Mellitus, Experimental/immunology
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Experimental/prevention & control
- Diabetes Mellitus, Type 1/immunology
- Diabetes Mellitus, Type 1/pathology
- Diabetes Mellitus, Type 1/prevention & control
- Enzyme-Linked Immunosorbent Assay
- Immunohistochemistry
- Immunologic Factors/chemistry
- Immunologic Factors/pharmacokinetics
- Immunologic Factors/therapeutic use
- Inflammation Mediators/immunology
- Islets of Langerhans/drug effects
- Islets of Langerhans/immunology
- Islets of Langerhans/pathology
- Male
- Mice
- Mice, Inbred CBA
- Mice, Inbred NOD
- Molecular Structure
- Nitric Oxide/biosynthesis
- Oxazoles/chemistry
- Oxazoles/pharmacokinetics
- Oxazoles/therapeutic use
- Reverse Transcriptase Polymerase Chain Reaction
- Streptozocin
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Gumieniczek A, Hopkała H, Roliński J, Bojarska-Junak A. Antioxidative and anti-inflammatory effects of repaglinide in plasma of diabetic animals. Pharmacol Res 2005; 52:162-6. [PMID: 15967382 DOI: 10.1016/j.phrs.2005.02.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 02/09/2005] [Accepted: 02/10/2005] [Indexed: 11/20/2022]
Abstract
Oxidative stress, defined as an imbalance between the production of reactive oxygen species (ROS) and antioxidant defense, is considered to be an important pathogenic factor in diabetes mellitus and its complications. In diabetic state, ROS might also be implicated in promoting a state of systemic inflammation. Recently, it was demonstrated that antioxidant therapy could be used to stop the initiation and propagation of this inflammatory response. Repaglinide is a new oral antidiabetic agent with a possible antioxidant activity. Therefore, in the present study, a possible therapeutic value of repaglinide in ameliorating the oxidative and inflammatory processes was tested in diabetic animals. In the study, the levels of total antioxidant status (TAS), ascorbic acid (AA), protein carbonyl groups (PCG) and interleukin-6 (IL-6) were determined in plasma of diabetic rabbits after 4 and 8 weeks of repaglinide treatment (1mg daily). Ex vivo analysis revealed that there were significant differences in these markers between hyperglycemic and control animals (P<0.05). Some of these parameters were ameliorated by repaglinide treatment. In diabetic rabbits treated with repaglinide, protein oxidation was diminished by 17.8% after 8 weeks of experiment. The level of AA in plasma of diabetic treated animals was higher than in non-treated diabetic groups (by 9.4 and 22.6% after 4 and 8 weeks, respectively). In diabetic treated animals, the TAS level was also significantly increased (by 23.6 and 16.7%). However, in diabetic rabbits, repaglinide did not affect the concentration of IL-6.
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Affiliation(s)
- Anna Gumieniczek
- Department of Medicinal Chemistry, Medical University of Lublin, Chodźki Str. 6, 20-093 Lublin, Poland.
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