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Gonuguntla S, Humphrey RK, Gorantla A, Hao E, Jhala US. Stress-induced pseudokinase TRB3 augments IL1β signaling by interacting with Flightless homolog 1. J Biol Chem 2023; 299:104803. [PMID: 37172723 PMCID: PMC10432976 DOI: 10.1016/j.jbc.2023.104803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 04/20/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023] Open
Abstract
Interleukin-1β is one of the most potent inducers of beta cell inflammation in the lead-up to type 1 diabetes. We have previously reported that IL1β-stimulated pancreatic islets from mice with genetic ablation of stress-induced pseudokinase TRB3(TRB3KO) show attenuated activation kinetics for the MAP3K MLK3 and JNK stress kinases. However, JNK signaling constitutes only a portion of the cytokine-induced inflammatory response. Here we report that TRB3KO islets also show a decrease in amplitude and duration of IL1β-induced phosphorylation of TAK1 and IKK, kinases that drive the potent NF-κB proinflammatory signaling pathway. We observed that TRB3KO islets display decreased cytokine-induced beta cell death, preceded by a decrease in select downstream NF-κB targets, including iNOS/NOS2 (inducible nitric oxide synthase), a mediator of beta cell dysfunction and death. Thus, loss of TRB3 attenuates both pathways required for a cytokine-inducible, proapoptotic response in beta cells. In order to better understand the molecular basis of TRB3-enhanced, post-receptor IL1β signaling, we interrogated the TRB3 interactome using coimmunoprecipitation followed by mass spectrometry to identify immunomodulatory protein Flightless homolog 1 (Fli1) as a novel, TRB3-interacting protein. We show that TRB3 binds and disrupts Fli1-dependent sequestration of MyD88, thereby increasing availability of this most proximal adaptor required for IL1β receptor-dependent signaling. Fli1 sequesters MyD88 in a multiprotein complex resulting in a brake on the assembly of downstream signaling complexes. By interacting with Fli1, we propose that TRB3 lifts the brake on IL1β signaling to augment the proinflammatory response in beta cells.
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Affiliation(s)
- Sumati Gonuguntla
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California, USA
| | - Rohan K Humphrey
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California, USA
| | - Akshita Gorantla
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California, USA
| | - Ergeng Hao
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California, USA
| | - Ulupi S Jhala
- Pediatric Diabetes Research Center, University of California San Diego, La Jolla, California, USA.
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2
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Alyami NM, Almeer R, Alyami HM. Role of green synthesized platinum nanoparticles in cytotoxicity, oxidative stress, and apoptosis of human colon cancer cells (HCT-116). Heliyon 2022; 8:e11917. [PMID: 36506358 PMCID: PMC9732314 DOI: 10.1016/j.heliyon.2022.e11917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 08/12/2022] [Accepted: 11/18/2022] [Indexed: 11/27/2022] Open
Abstract
Progresses in the medicinal application of nanocompounds were accepted for the treatment of cancer. Nanoparticles-based therapy is of benefit for effective biodistribution and specific targeting. The current study investigated the anticancer effect of green synthesized platinum nanoparticles (PtNPs) against colon cancer cells (HCT-116). Flow cytometry and ELISA techniques were employed for detecting apoptotic and oxidative stress markers. Furthermore, PtNPs-lycopene (PtNPs-LP) on cell migration and invasion of HCT-116 cells was also examined. The PtNPs-LP was capable of diminishing cell proliferation and viability of HCT-116 cells in a dose-dependent mode. After treatment with PtNPs-LP, a significant increase in pro-apoptotic Bax and caspase-3 and a decrease in anti-apoptotic Bcl-2 was observed in treated cells that subsequently released cytochrome C into its cytoplasm, initiating cell death. Moreover, PtNPs-LP induced excessive generation of reactive oxygen species (ROS) and oxidative stress in cancer cells. In conclusion, PtNPs-LP exerts an antitumor effect against colon cancer cells via mediating important mechanisms such as cytotoxicity, apoptosis, and oxidative stress.
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Affiliation(s)
- Nouf M. Alyami
- Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia,Corresponding author.
| | - Rafa Almeer
- Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Hanadi M. Alyami
- Specialized Dentistry Department, King Fahad Medical City, Riyadh 11451, Saudi Arabia
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Kaneko YK, Morioka A, Sano M, Tashiro M, Watanabe N, Kasahara N, Nojiri M, Ishiwatari C, Ichinose K, Minami A, Suzuki T, Yamaguchi M, Kimura T, Ishikawa T. Asymmetric dimethylarginine accumulation under hyperglycemia facilitates β-cell apoptosis via inhibiting nitric oxide production. Biochem Biophys Res Commun 2022; 637:108-116. [DOI: 10.1016/j.bbrc.2022.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 10/28/2022] [Accepted: 11/06/2022] [Indexed: 11/10/2022]
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Sasikumar R, Jyoti Das A, Chandra Deka S. In vitro cytoprotective activity of cyanidin 3-glucoside extracts from Haematocarpus validus pomace on streptozotocin induced oxidative damage in pancreatic β-cells. Saudi J Biol Sci 2021; 28:5338-5348. [PMID: 34466113 PMCID: PMC8381084 DOI: 10.1016/j.sjbs.2021.05.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 05/24/2021] [Accepted: 05/24/2021] [Indexed: 12/02/2022] Open
Abstract
Cyanidin-3-glucoside (C3Ghv) compounds were purified and isolated from the anthocyanins extract of Haematocarpus validus. C3Ghv were studied for antioxidant and cytoprotective properties on pancreatic β-cells of rat insulinoma cells (RINm5F) against the oxidative stress induced by streptozotocin (STZ). The exposure of RINm5F cells to C3Ghv at concentration of 100 and 200 μg/mL for 24 h reduced 10% and 23% cell viability, respectively, as compared to control cells. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) increased the cell viability by 29% as compared to control, on being treated with STZ (10 mM) for 24 h. The pre-treatment of RINm5F cells with C3Ghv (50 µg/mL) for 24 h followed by exposure to STZ (10 mM) for 1 h decreased the generation of reactive oxygen species (ROS) by 57%, generation of nitric oxide by 22.8%, generation of malondialdehyde (MDA) by 32%, the production of p-ERK ½ by 83%, p-JNK by 82.6%, p-MEK by 57%, and p-p38 MAPK by 64%. The C3Ghv treatment also decreased the ratio of apoptotic proteins Bax to Bcl-2 by 61%, and improved the M2 phase of cell cycle by 75% as compared to STZ treated cells. The overall results suggest that C3Ghv protects pancreatic β-cells against oxidative stress-induced apoptosis, thereby implicating the significant role of C3Ghv as an antidiabetic agent.
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Affiliation(s)
- Raju Sasikumar
- Department of Agribusiness Management and Food Technology, North-Eastern Hill University (NEHU), Tura Campus, West Garo Hills, Tura 794002, Meghalaya, India
| | - Arub Jyoti Das
- Department of Food Engineering and Technology, Tezpur University, Tezpur, Assam, India
| | - Sankar Chandra Deka
- Department of Food Engineering and Technology, Tezpur University, Tezpur, Assam, India
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Sahebnasagh A, Saghafi F, Negintaji S, Hu T, Shabani-Boroujeni M, Safdari M, Ghaleno HR, Miao L, Qi Y, Wang M, Liao P, Sureda A, Simal-Gándara J, Nabavi SM, Xiao J. Nitric Oxide and Immune Responses in Cancer: Searching for New Therapeutic Strategies. Curr Med Chem 2021; 29:1561-1595. [PMID: 34238142 DOI: 10.2174/0929867328666210707194543] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/05/2021] [Accepted: 05/15/2021] [Indexed: 02/08/2023]
Abstract
In recent years, there has been an increasing interest in understanding the mysterious functions of nitric oxide (NO) and how this pleiotropic signaling molecule contributes to tumorigenesis. This review attempts to expose and discuss the information available on the immunomodulatory role of NO in cancer and recent approaches to the role of NO donors in the area of immunotherapy. To address the goal, the following databases were searched to identify relevant literature concerning empirical evidence: The Cochrane Library, Pubmed, Medline, EMBASE from 1980 through March 2020. Valuable attempts have been made to develop distinctive NO-based cancer therapy. Although the data do not allow generalization, the evidence seems to indicate that low / moderate levels may favor tumorigenesis while higher levels would exert anti-tumor effects. In this sense, the use of NO donors could have an important therapeutic potential within immunotherapy, although there are still no clinical trials. The emerging understanding of NO-regulated immune responses in cancer may help unravel the recent features of this "double-edged sword" in cancer physiological and pathologic processes and its potential use as a therapeutic agent for cancer treatment. In short, in this review, we discuss the complex cellular mechanism in which NO, as a pleiotropic signaling molecule, participates in cancer pathophysiology. We also debate the dual role of NO in cancer and tumor progression, and clinical approaches for inducible nitric oxide synthase (iNOS) based therapy against cancer.
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Affiliation(s)
- Adeleh Sahebnasagh
- Clinical Research Center, Department of Internal Medicine, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Fatemeh Saghafi
- Department of Clinical Pharmacy, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Sina Negintaji
- Student Research Committee, School of Pharmacy, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Tingyan Hu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Mojtaba Shabani-Boroujeni
- Department of Clinical Pharmacy, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammadreza Safdari
- Department of Orthopedic Surgery, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Hassan Rezai Ghaleno
- Department of Surgery, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Lingchao Miao
- Institute of Chinese Medical Sciences, State Key Laboratory of Quality Research in Chinese Medicine, University of Macau, Macao, China
| | - Yaping Qi
- Purdue Quantum Science and Engineering Institute, Purdue University, West Lafayette, IN 47907, United States
| | - Mingfu Wang
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road. Hong Kong, China
| | - Pan Liao
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, United States
| | - Antoni Sureda
- Research Group on Community Nutrition and Oxidative Stress, University of the Balearic Islands, Palma de Mallorca, Spain
| | - Jesus Simal-Gándara
- Nutrition and Bromatology Group, Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo - Ourense Campus, E-32004 Ourense, Spain
| | - Seyed Mohammad Nabavi
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Jianbo Xiao
- Nutrition and Bromatology Group, Department of Analytical Chemistry and Food Science, Faculty of Food Science and Technology, University of Vigo - Ourense Campus, E-32004 Ourense, Spain
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Mussa BM, Srivastava A, Mohammed AK, Verberne AJM. Nitric oxide interacts with cholinoceptors to modulate insulin secretion by pancreatic β cells. Pflugers Arch 2020; 472:1469-1480. [PMID: 32803305 PMCID: PMC7476970 DOI: 10.1007/s00424-020-02443-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/17/2020] [Accepted: 07/31/2020] [Indexed: 01/09/2023]
Abstract
Dysfunction of the pancreatic β cells leads to several chronic disorders including diabetes mellitus. Several mediators and mechanisms are known to be involved in the regulation of β cell secretory function. In this study, we propose that cytokine-induced nitric oxide (NO) production interacts with cholinergic mechanisms to modulate insulin secretion from pancreatic β cells. Using a rat insulinoma cell line INS-1, we demonstrated that β cell viability decreases significantly in the presence of SNAP (NO donor) in a concentration- and time-dependent manner. Cell viability was also found to be decreased in the presence of a combined treatment of SNAP with SMN (muscarinic receptor antagonist). We then investigated the impact of these findings on insulin secretion and found a significant reduction in glucose uptake by INS-1 cells in the presence of SNAP and SMN as compared with control. Nitric oxide synthase 3 gene expression was found to be significantly reduced in response to combined treatment with SNAP and SMN suggesting an interaction between the cholinergic and nitrergic systems. The analysis of gene and protein expression further pin-pointed the involvement of M3 muscarinic receptors in the cholinergic pathway. Upon treatment with cytokines, reduced cell viability was observed in the presence of TNF-α and IFN-γ. A significant reduction in insulin secretion was also noted after treatment with TNF-α and IFN-γ and IL1-β. The findings of the present study have shown for the first time that the inhibition of the excitatory effects of cholinergic pathways on glucose-induced insulin secretion may cause β cell injury and dysfunction of insulin secretion in response to cytokine-induced NO production.
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Affiliation(s)
- Bashair M Mussa
- Basic Medical Science Department, College of Medicine, University of Sharjah, P.O. Box: 27272, Sharjah, United Arab Emirates.
| | - Ankita Srivastava
- Sharjah Institute for Medical Research, University of Sharjah, P.O. Box: 27272, Sharjah, United Arab Emirates
| | - Abdul Khader Mohammed
- Sharjah Institute for Medical Research, University of Sharjah, P.O. Box: 27272, Sharjah, United Arab Emirates
| | - Anthony J M Verberne
- Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, 3084, Australia
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7
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Shahraki ZS, Karbalaei N, Nemati M. Improving effect of combined inorganic nitrate and nitric oxide synthase inhibitor on pancreatic oxidative stress and impaired insulin secretion in streptozotocin induced-diabetic rats. J Diabetes Metab Disord 2020; 19:353-362. [PMID: 32550186 DOI: 10.1007/s40200-020-00516-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/11/2020] [Indexed: 12/16/2022]
Abstract
Purpose The aim of this study was to evaluate the effect of dietary nitrate on secretory function of pancreatic islet and oxidative stress status in streptozotocin (STZ) induced type 1 diabetes in absence or presence of nitric oxide synthase inhibitor (L-NAME). Methods Fifty adult male sprague-dawly rats were divided into 5 groups: controls (C), diabetes (D), diabetes+nitrate (DN), diabetes +L-NAME (D + Ln), and diabetes+nitrate+L-NAME (DN + Ln) for 45 days. The concentrations of sodium nitrate and L-NAME were respectively 80 mg/L in drinking water and 5 mg/kg intraperitoneally. Body weight gain, plasma levels of glucose and insulin, islet insulin secretion and content, lipid peroxidation and antioxidant status in the pancreas of rats were determined. Results Compared to control group, the body weight gain and plasma insulin level were significantly decreased and plasma glucose and pancreatic NO and MDA concentrations and antioxidant enzymes activities were significantly increased in the STZ diabetic rats. In the diabetic rats, nitrate alone significantly reduced plasma glucose and increased pancreatic SOD and GPx activity. Reduced plasma glucose, pancreatic MDA and NO concentrations and increased plasma insulin level and pancreatic islet insulin secretion were observed in D + Ln and DN + Ln groups. Antioxidant enzymes activities were increased in diabetic rats which received combination of nitrate and L-NAME. Conclusions Our results showed that nitrate without effect on pancreatic islet insulin content and secretion decreased the blood glucose and slightly moderate oxidative stress and its effects in the presence of L-NAME on glucose hemostasis and pancreatic insulin secretion higher than those of nitrate alone.
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Affiliation(s)
- Zahra Shabgard Shahraki
- Department of Physiology, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Narges Karbalaei
- Department of Physiology, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.,Histomorphometry and Stereology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Marzieh Nemati
- Department of Physiology, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
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8
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Fagbohun OF, Awoniran PO, Babalola OO, Agboola FK, Msagati TAM. Changes in the biochemical, hematological and histopathological parameters in STZ-Induced diabetic rats and the ameliorative effect of Kigelia africana fruit extract. Heliyon 2020; 6:e03989. [PMID: 32462092 PMCID: PMC7243140 DOI: 10.1016/j.heliyon.2020.e03989] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 04/01/2020] [Accepted: 04/12/2020] [Indexed: 02/07/2023] Open
Abstract
Background Biochemical, hematological and histological changes are major observable clinical and pathological factors associated with Diabetes mellitus. Derangement in the levels of these parameters increases the risk of the development of complications. In another hand, gastrointestinal intolerance due to the development of lactic acidosis on the gastrointestinal tract and the intestinal microbiome is the toxic side effect of various synthetic antidiabetic agents. The use of Kigelia africana fruit extract for the treatment of diabetes has been scientifically validated. This study therefore aimed at investigating changes in the biochemical, hematological and histological parameters as well as the determination of the functional groups present in the hexane fraction of the fruit. Methods The fruits were extracted with ethanol and partitioned with n-hexane to obtain the hexane fraction. Diabetic rats induced with streptozotocin (STZ) were divided into 5 groups of 5 animals each and treated with 100, 200 and 400 mg/kg body weight (BW) hexane fraction alongside reference standard; glibenclamide. Fasting blood glucose levels and their body weights were monitored weekly. Animals were sacrificed at the end of 28-day treatment. Blood, liver, and kidney were collected for biochemical, hematological and histopathological analyses. Fourier transform infrared resonance (FTIR) spectroscopic analysis was carried out on the hexane fraction for functional group determination. Results The hexane fraction of K. africana fruit extract decreased fasting blood glucose (FBG) levels significantly with ameliorative effects on the hematological parameters such as packed cell volume (PCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), and red blood cells (RBC) etc. There were significant regenerative differences in the biochemical activities as well as the renal cortex and midzone sections of the rat's kidney and liver when compared with untreated diabetic rats. The presence of polyphenolic functional groups via FTIR analysis suggested high antioxidant activities of the fruit extract. Conclusion The use of Kigelia africana fruit extracts protects against biochemical, hematological and histological changes that are injurious to diabetic patients. Therefore, Kigelia africana fruit is a good hepatic- and nephroprotective agent and has a hemato-protective ability.
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Affiliation(s)
- Oladapo F Fagbohun
- Department of Biomedical Engineering, First Technical University, Ibadan, Oyo State, Nigeria
| | - Paul O Awoniran
- Department of Anatomy and Cell Biology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Olubunmi O Babalola
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Femi K Agboola
- Department of Biochemistry and Molecular Biology, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria
| | - Titus A M Msagati
- Nanotechnology and Water Sustainability Research Unit, College of Science Engineering and Technology, University of South Africa (UNISA), Florida Park, Johannesburg, South Africa
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Oleson BJ, Corbett JA. Can insulin secreting pancreatic β-cells provide novel insights into the metabolic regulation of the DNA damage response? Biochem Pharmacol 2020; 176:113907. [PMID: 32171728 DOI: 10.1016/j.bcp.2020.113907] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 03/06/2020] [Indexed: 12/18/2022]
Abstract
Insulin, produced by pancreatic β-cells, is responsible for the control of whole-body glucose metabolism. Insulin is secreted by pancreatic β-cells in a tightly regulated process that is controlled by the serum level of glucose, glucose sensing and glucose oxidative metabolism. The regulation of intermediary metabolism in β-cells is unique as these cells oxidize glucose to CO2 on substrate supply while mitochondrial oxidative metabolism occurs on demand, for the production of intermediates or energy production, in most cell types. This review discusses recent findings that the regulation of intermediary metabolism by nitric oxide attenuates the DNA damage response (DDR) and DNA damage-dependent apoptosis in a β-cell selective manner. Specific focus is placed on the mechanisms by which iNOS derived nitric oxide (low micromolar levels) regulates DDR activation via the inhibition of intermediary metabolism. The physiological significance of the association of metabolism, nitric oxide and DDR signaling for cancer biology and diabetes is discussed.
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Affiliation(s)
- Bryndon J Oleson
- From the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - John A Corbett
- From the Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Gurunathan S, Jeyaraj M, La H, Yoo H, Choi Y, Do JT, Park C, Kim JH, Hong K. Anisotropic Platinum Nanoparticle-Induced Cytotoxicity, Apoptosis, Inflammatory Response, and Transcriptomic and Molecular Pathways in Human Acute Monocytic Leukemia Cells. Int J Mol Sci 2020; 21:ijms21020440. [PMID: 31936679 PMCID: PMC7014054 DOI: 10.3390/ijms21020440] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 12/18/2022] Open
Abstract
The thermoplasmonic properties of platinum nanoparticles (PtNPs) render them desirable for use in diagnosis, detection, therapy, and surgery. However, their toxicological effects and impact at the molecular level remain obscure. Nanotoxicology is mainly focused on the interactions of nanostructures with biological systems, particularly with an emphasis on elucidating the relationship between the physical and chemical properties such as size and shape. Therefore, we hypothesized whether these unique anisotropic nanoparticles could induce cytotoxicity similar to that of spherical nanoparticles and the mechanism involved. Thus, we synthesized unique and distinct anisotropic PtNPs using lycopene as a biological template and investigated their biological activities in model human acute monocytic leukemia (THP-1) macrophages. Exposure to PtNPs for 24 h dose-dependently decreased cell viability and proliferation. Levels of the cytotoxic markers lactate dehydrogenase and intracellular protease significantly and dose-dependently increased with PtNP concentration. Furthermore, cells incubated with PtNPs dose-dependently produced oxidative stress markers including reactive oxygen species (ROS), malondialdehyde, nitric oxide, and carbonylated protein. An imbalance in pro-oxidants and antioxidants was confirmed by significant decreases in reduced glutathione, thioredoxin, superoxide dismutase, and catalase levels against oxidative stress. The cell death mechanism was confirmed by mitochondrial dysfunction and decreased ATP levels, mitochondrial copy numbers, and PGC-1α expression. To further substantiate the mechanism of cell death mediated by endoplasmic reticulum stress (ERS), we determined the expression of the inositol-requiring enzyme (IRE1), (PKR-like ER kinase) PERK, activating transcription factor 6 (ATF6), and activating transcription factor 4 ATF4, the apoptotic markers p53, Bax, and caspase 3, and the anti-apoptotic marker Bcl-2. PtNPs could activate ERS and apoptosis mediated by mitochondria. A proinflammatory response to PtNPs was confirmed by significant upregulation of interleukin-1-beta (IL-1β), interferon γ (IFNγ), tumor necrosis factor alpha (TNFα), and interleukin (IL-6). Transcriptomic and molecular pathway analyses of THP-1 cells incubated with the half maximal inhibitory concentration (IC50) of PtNPs revealed the altered expression of genes involved in protein misfolding, mitochondrial function, protein synthesis, inflammatory responses, and transcription regulation. We applied transcriptomic analyses to investigate anisotropic PtNP-induced toxicity for further mechanistic studies. Isotropic nanoparticles are specifically used to inhibit non-specific cellular uptake, leading to enhanced in vivo bio-distribution and increased targeting capabilities due to the higher radius of curvature. These characteristics of anisotropic nanoparticles could enable the technology as an attractive platform for nanomedicine in biomedical applications.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Kwonho Hong
- Correspondence: ; Tel.: +82-2-450-0560; Fax: +82-2-444-3490
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11
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Roma LP, Jonas JC. Nutrient Metabolism, Subcellular Redox State, and Oxidative Stress in Pancreatic Islets and β-Cells. J Mol Biol 2019; 432:1461-1493. [PMID: 31634466 DOI: 10.1016/j.jmb.2019.10.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 09/25/2019] [Accepted: 10/10/2019] [Indexed: 01/01/2023]
Abstract
Insulin-secreting pancreatic β-cells play a critical role in blood glucose homeostasis and the development of type 2 diabetes (T2D) in the context of insulin resistance. Based on data obtained at the whole cell level using poorly specific chemical probes, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide have been proposed to contribute to the stimulation of insulin secretion by nutrients (positive role) and to the alterations of cell survival and secretory function in T2D (negative role). This raised the controversial hypothesis that any attempt to decrease β-cell oxidative stress and apoptosis in T2D would further impair insulin secretion. Over the last decade, the development of genetically-encoded redox probes that can be targeted to cellular compartments of interest and are specific of redox couples allowed the evaluation of short- and long-term effects of nutrients on β-cell redox changes at the subcellular level. The data indicated that the nutrient regulation of β-cell redox signaling and ROS toxicity is far more complex than previously thought and that the subcellular compartmentation of these processes cannot be neglected when evaluating the mechanisms of ROS production or the efficacy of antioxidant enzymes and antioxidant drugs under glucolipotoxic conditions and in T2D. In this review, we present what is currently known about the compartmentation of redox homeostatic systems and tools to investigate it. We then review data about the effects of nutrients on β-cell subcellular redox state under normal conditions and in the context of T2D and discuss challenges and opportunities in the field.
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Affiliation(s)
- Leticia P Roma
- Universität des Saarlandes, Biophysics Department, Center for Human and Molecular Biology, Kirbergerstrasse Building 48, 66421, Homburg/Saar, Germany
| | - Jean-Christophe Jonas
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), B-1200 Brussels, Belgium.
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Erukainure OL, Oyebode OA, Ijomone OM, Chukwuma CI, Koorbanally NA, Islam MS. Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine modulates glucose homeostasis by enhancing insulin secretion and inhibiting redox imbalance in a rat model of diabetes induced by high fructose diet and streptozotocin. JOURNAL OF ETHNOPHARMACOLOGY 2019; 237:159-170. [PMID: 30902747 DOI: 10.1016/j.jep.2019.03.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/12/2019] [Accepted: 03/16/2019] [Indexed: 05/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Raffia palm (Raphia hookeri) wine (RPW) is amongst the natural products from plants, utilized singly or in combination with other medicinal plants for the treatment of several ailments including Diabetes Mellitus (DM). However, there is a scientific dearth on its antidiabetic activity. AIM The antidiabetic effect of RPW and its possible mechanism of actions were investigated in diabetic rats. METHODS Four groups of male SD rats were first supplied with 10% fructose solution ad libitum for 2 weeks instead of drinking water followed by an intraperitonial injection of streptozotocin (40 mg/kg) to induce diabetes. Two diabetic groups were administered RPW at 150 and 300 mg/kg bodyweight (BW) respectively; a group was administered with metformin, while the other one was served as a negative control. Two groups of normal rats were administered with water and RPW (300 mg/kg BW) and served as normal control and normal toxicology group, respectively. RESULTS Five weeks treatment of RPW led to significant (p < 0.05) increase in serum insulin and HDL-c levels with concomitant reduction in blood glucose, fructosamine, ALT, uric acid, triglycerides and LDL-c levels in diabetic rats. Rats treated with RPW had elevated levels of GSH, SOD, catalase, ATPase and α-amylase activities, while reduced NO level and myeloperoxidase activity was observed in their serum and pancreatic tissues. RPW also improved pancreatic β-cell function and restored β- and acinar cells morphology, and capillary networks. The activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose-6-phosphatase, and acetylcholinesterase were also inhibited in RPW-treated diabetic rats, with concomitant down regulation of Nrf2 gene expression. CONCLUSION The data of this study suggest that RPW modulates glucose homeostasis by enhancing insulin secretion as well as inhibiting redox imbalance in diabetic rats, which may be attributed to the synergetic effects of its phytochemical constituents as identified by GC-MS analysis.
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Affiliation(s)
- Ochuko L Erukainure
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, (Westville Campus), Durban 4000, South Africa; Nutrition and Toxicology Division, Federal Institute of Industrial Research, Lagos, Nigeria
| | - Olajumoke A Oyebode
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, (Westville Campus), Durban 4000, South Africa
| | | | - Chika I Chukwuma
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, (Westville Campus), Durban 4000, South Africa; Department of Health and Environmental Studies, Central University of Technology, Bloemfontein, South Africa
| | - Neil A Koorbanally
- School of Chemistry and Physics, University of KwaZulu-Natal, (Westville Campus), Durban 4000, South Africa
| | - Md Shahidul Islam
- Department of Biochemistry, School of Life Sciences, University of KwaZulu-Natal, (Westville Campus), Durban 4000, South Africa.
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Yang J, Sun Y, Xu F, Liu W, Hayashi T, Hattori S, Ushiki‐Kaku Y, Onodera S, Tashiro S, Ikejima T. Silibinin protects rat pancreatic β‐cell through up‐regulation of estrogen receptors' signaling against amylin‐ or Aβ
1–42
‐induced reactive oxygen species/reactive nitrogen species generation. Phytother Res 2019; 33:998-1009. [DOI: 10.1002/ptr.6293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/30/2018] [Accepted: 12/06/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Jing Yang
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Yue Sun
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Fanxing Xu
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Weiwei Liu
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Toshihiko Hayashi
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
- Department of Chemistry and Life science, School of Advanced EngineeringKogakuin University Tokyo Japan
| | - Shunji Hattori
- Nippi Research Institute of BiomatrixNippi, Incorporated Toride Japan
| | - Yuko Ushiki‐Kaku
- Nippi Research Institute of BiomatrixNippi, Incorporated Toride Japan
| | - Satoshi Onodera
- Department of Clinical and Biomedical SciencesShowa Pharmaceutical University Tokyo Japan
| | - Shin‐ichi Tashiro
- Department of Medical Education and Primary CareKyoto Prefectural University of Medicine Kyoto Japan
| | - Takashi Ikejima
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
- Key Laboratory of Computational Chemistry‐Based Natural Antitumor Drug Research & DevelopmentShenyang Pharmaceutical University Shenyang China
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14
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Oleson BJ, Corbett JA. Dual Role of Nitric Oxide in Regulating the Response of β Cells to DNA Damage. Antioxid Redox Signal 2018; 29:1432-1445. [PMID: 28978225 PMCID: PMC6166691 DOI: 10.1089/ars.2017.7351] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/09/2017] [Indexed: 01/09/2023]
Abstract
SIGNIFICANCE Cytokines released in and around pancreatic islets during islet inflammation are believed to contribute to impaired β cell function and β cell death during the development of diabetes. Nitric oxide, produced by β cells in response to cytokine exposure, controls many of the responses of β cells during islet inflammation. Recent Advances: Although nitric oxide has been shown to inhibit insulin secretion and oxidative metabolism and induce DNA damage in β cells, it also activates protective pathways that promote recovery of insulin secretion and oxidative metabolism and repair of damaged DNA. Recent studies have identified a novel role for nitric oxide in selectively regulating the DNA damage response in β cells. CRITICAL ISSUES Does nitric oxide mediate cytokine-induced β cell damage, or is nitric oxide produced by β cells in response to cytokines to protect β cells from damage? FUTURE DIRECTIONS β cells appear to be the only islet endocrine cell type capable of responding to proinflammatory cytokines with the production of nitric oxide, and these terminally differentiated cells have a limited capacity to regenerate. It is likely that there is a physiological purpose for this response, and understanding this could open new areas of study regarding the loss of functional β cell mass during diabetes development.
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Affiliation(s)
- Bryndon J. Oleson
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - John A. Corbett
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin
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15
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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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16
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Murata M, Adachi H, Oshima S, Kurabayashi M. Glucose fluctuation and the resultant endothelial injury are correlated with pancreatic β cell dysfunction in patients with coronary artery disease. Diabetes Res Clin Pract 2017; 131:107-115. [PMID: 28743060 DOI: 10.1016/j.diabres.2017.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/15/2017] [Accepted: 07/03/2017] [Indexed: 11/22/2022]
Abstract
AIMS We evaluated whether glucose fluctuation (GF) causes vascular endothelial injury and affects glucometabolic factors during lengthy oral glucose tolerance test (OGTT). METHODS We enrolled consecutive 116 patients with coronary artery disease (CAD) who were performed coronary angiography and 4-h OGTT. Blood samples were collected before and 4h after glucose load to measure endothelial injury factor [von Willebrand factor (vWF) and vWF/a disintegrin-like and metalloproteinase with thrombospondin type-1 motifs 13 (ADAMTS-13) ratio]. GF was defined as maximum - minimum blood glucose levels during 4-h OGTT. We estimated the relationship between GF and glucometabolic factors. RESULTS vWV and vWF/ADAMTS-13 ratio were significantly correlated with GF during 4-h OGTT. GF was significantly correlated with homeostasis model to assess insulin resistance (HOMA-IR) (R=0.262), Matsuda index (R=-0.405), insulinogenic index (R=-0.336), HbA1c (R=0.281) and disposition index (R=-0.672). When dividing patients into impaired and preserved category groups according to the average value of GF (122mg/dL), adjusted to age, sex, HOMA-β, insulinogenic index, HOMA-IR, Matsuda index and HbA1c, disposition index was an independent risk factor for impaired GF [odds ratio (95% confidence interval): 2.87 (1.70-4.83), P<0.001]. CONCLUSION Pancreatic β cell dysfunction is associated with GF and causes endothelial injury in CAD patients.
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Affiliation(s)
- Makoto Murata
- Gunma Prefectural Cardiovascular Center, Department of Cardiology, 3-12 Kameizumimachi, Maebashi, Gunma 371-0004, Japan.
| | - Hitoshi Adachi
- Gunma Prefectural Cardiovascular Center, Department of Cardiology, 3-12 Kameizumimachi, Maebashi, Gunma 371-0004, Japan.
| | - Shigeru Oshima
- Gunma Prefectural Cardiovascular Center, Department of Cardiology, 3-12 Kameizumimachi, Maebashi, Gunma 371-0004, Japan.
| | - Masahiko Kurabayashi
- Gunma University Graduate School of Medicine, Department of Medicine and Biological Science, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
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17
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Sandoval A, Duran P, Gandini MA, Andrade A, Almanza A, Kaja S, Felix R. Regulation of L-type Ca V1.3 channel activity and insulin secretion by the cGMP-PKG signaling pathway. Cell Calcium 2017; 66:1-9. [PMID: 28807144 DOI: 10.1016/j.ceca.2017.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/03/2017] [Accepted: 05/12/2017] [Indexed: 12/28/2022]
Abstract
cGMP is a second messenger widely used in the nervous system and other tissues. One of the major effectors for cGMP is the serine/threonine protein kinase, cGMP-dependent protein kinase (PKG), which catalyzes the phosphorylation of a variety of proteins including ion channels. Previously, it has been shown that the cGMP-PKG signaling pathway inhibits Ca2+ currents in rat vestibular hair cells and chromaffin cells. This current allegedly flow through voltage-gated CaV1.3L-type Ca2+ channels, and is important for controlling vestibular hair cell sensory function and catecholamine secretion, respectively. Here, we show that native L-type channels in the insulin-secreting RIN-m5F cell line, and recombinant CaV1.3 channels heterologously expressed in HEK-293 cells, are regulatory targets of the cGMP-PKG signaling cascade. Our results indicate that the CaVα1 ion-conducting subunit of the CaV1.3 channels is highly expressed in RIN-m5F cells and that the application of 8-Br-cGMP, a membrane-permeable analogue of cGMP, significantly inhibits Ca2+ macroscopic currents and impair insulin release stimulated with high K+. In addition, KT-5823, a specific inhibitor of PKG, prevents the current inhibition generated by 8-Br-cGMP in the heterologous expression system. Interestingly, mutating the putative phosphorylation sites to residues resistant to phosphorylation showed that the relevant PKG sites for CaV1.3 L-type channel regulation centers on two amino acid residues, Ser793 and Ser860, located in the intracellular loop connecting the II and III repeats of the CaVα1 pore-forming subunit of the channel. These findings unveil a novel mechanism for how the cGMP-PKG signaling pathway may regulate CaV1.3 channels and contribute to regulate insulin secretion.
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Affiliation(s)
| | - Paz Duran
- Departamento de Biología Celular, Cinvestav-IPN, Ciudad de México, Mexico
| | - María A Gandini
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Arturo Andrade
- Department of Biological Sciences, University of New Hampshire, Durham, NH, USA
| | - Angélica Almanza
- Dirección de Investigaciones en Neurociencias, Instituto Nacional de Psiquiatría, Ramón de la Fuente Muñiz, Ciudad de México, Mexico
| | - Simon Kaja
- Department of Ophtalmology and Molecular Pharmacology & Therapeutics, Loyola University, Chicago, Strich School of Medicine, Maywood, IL, USA
| | - Ricardo Felix
- Departamento de Biología Celular, Cinvestav-IPN, Ciudad de México, Mexico.
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18
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Bucris E, Beck A, Boura-Halfon S, Isaac R, Vinik Y, Rosenzweig T, Sampson SR, Zick Y. Prolonged insulin treatment sensitizes apoptosis pathways in pancreatic β cells. J Endocrinol 2016; 230:291-307. [PMID: 27411561 DOI: 10.1530/joe-15-0505] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 12/11/2022]
Abstract
Insulin resistance results from impaired insulin signaling in target tissues that leads to increased levels of insulin required to control plasma glucose levels. The cycle of hyperglycemia and hyperinsulinemia eventually leads to pancreatic cell deterioration and death by a mechanism that is yet unclear. Insulin induces ROS formation in several cell types. Furthermore, death of pancreatic cells induced by oxidative stress could be potentiated by insulin. Here, we investigated the mechanism underlying this phenomenon. Experiments were done on pancreatic cell lines (Min-6, RINm, INS-1), isolated mouse and human islets, and on cell lines derived from nonpancreatic sources. Insulin (100nM) for 24h selectively increased the production of ROS in pancreatic cells and isolated pancreatic islets, but only slightly affected the expression of antioxidant enzymes. This was accompanied by a time- and dose-dependent decrease in cellular reducing power of pancreatic cells induced by insulin and altered expression of several ER stress response elements including a significant increase in Trb3 and a slight increase in iNos The effect on iNos did not increase NO levels. Insulin also potentiated the decrease in cellular reducing power induced by H2O2 but not cytokines. Insulin decreased the expression of MCL-1, an antiapoptotic protein of the BCL family, and induced a modest yet significant increase in caspase 3/7 activity. In accord with these findings, inhibition of caspase activity eliminated the ability of insulin to increase cell death. We conclude that prolonged elevated levels of insulin may prime apoptosis and cell death-inducing mechanisms as a result of oxidative stress in pancreatic cells.
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Affiliation(s)
- E Bucris
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel Mina and Everard Goodman Faculty of Life SciencesBar-Ilan University, Ramat-Gan, Israel
| | - A Beck
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel
| | - S Boura-Halfon
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel
| | - R Isaac
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel
| | - Y Vinik
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel
| | - T Rosenzweig
- Department of Molecular Biology and Nutritional StudiesAriel University, Ariel, Israel
| | - S R Sampson
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel Mina and Everard Goodman Faculty of Life SciencesBar-Ilan University, Ramat-Gan, Israel
| | - Y Zick
- Department of Molecular Cell BiologyWeizmann Institute of Science, Rehovot, Israel
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19
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Long-term in vivo polychlorinated biphenyl 126 exposure induces oxidative stress and alters proteomic profile on islets of Langerhans. Sci Rep 2016; 6:27882. [PMID: 27292372 PMCID: PMC4904407 DOI: 10.1038/srep27882] [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: 03/02/2016] [Accepted: 05/24/2016] [Indexed: 12/15/2022] Open
Abstract
It has been recently proposed that exposure to polychlorinated biphenyls (PCBs) is a risk factor to type 2 diabetes mellitus (DM2). We investigated this hypothesis using long-term in vivo PCB126 exposure to rats addressing metabolic, cellular and proteomic parameters. Male Wistar rats were exposed to PCB126 (0.1, 1 or 10 μg/kg of body weight/day; for 15 days) or vehicle by intranasal instillation. Systemic alterations were quantified by body weight, insulin and glucose tolerance, and blood biochemical profile. Pancreatic toxicity was measured by inflammatory parameters, cell viability and cycle, free radical generation, and proteomic profile on islets of Langerhans. In vivo PCB126 exposure enhanced the body weight gain, impaired insulin sensitivity, reduced adipose tissue deposit, and elevated serum triglycerides, cholesterol, and insulin levels. Inflammatory parameters in the pancreas and cell morphology, viability and cycle were not altered in islets of Langerhans. Nevertheless, in vivo PCB126 exposure increased free radical generation and modified the expression of proteins related to oxidative stress on islets of Langerhans, which are indicative of early β-cell failure. Data herein obtained show that long-term in vivo PCB126 exposure through intranasal route induced alterations on islets of Langerhans related to early end points of DM2.
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20
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Kaneko YK. Development and Analysis of Novel Therapeutic Targets to Improve Pancreatic β-Cell Function in Type 2 Diabetes. YAKUGAKU ZASSHI 2016; 136:1623-1629. [DOI: 10.1248/yakushi.16-00211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yukiko K. Kaneko
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka
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21
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Leite NDC, Montes EG, Fisher SV, Cancian CRC, de Oliveira JC, Martins-Pinge MC, Kanunfre CC, Souza KLA, Grassiolli S. Splenectomy attenuates obesity and decreases insulin hypersecretion in hypothalamic obese rats. Metabolism 2015; 64:1122-33. [PMID: 26026366 DOI: 10.1016/j.metabol.2015.05.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 04/23/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Obesity-induced abnormalities, such as insulin resistance, dyslipidemia and hypertension, are frequently correlated with low-grade inflammation, a process that may depend on normal spleen function. This study investigated the role of the spleen in the obesity induced by monosodium glutamate (MSG) treatment. MATERIALS/METHODS MSG-obese and lean control (CON) rats were subjected to splenectomy (SPL) or non-operated (NO). RESULTS MSG-NO rats presented a high adipose tissue content, insulin resistance, dyslipidemia and islet hypersecretion, accompanied by hypertrophy of both pancreatic islets and adipocytes when compared with CON-NO rats. In addition, changes in nitric oxide response were found in islets from the MSG-NO group without associated alterations in inducible nitric oxide synthase (iNOS) or IL1β expression. MSG-NO also presented increased leukocyte counts and augmented LPS-induced nitric oxide production in macrophages. Splenectomy of MSG-obese animals decreased insulin hypersecretion, normalized the nitric oxide response in the pancreatic islets, improved insulin sensitivity and reduced hypertrophy of both adipocytes and islets, when compared with MSG-NO rats. CONCLUSION Results show that splenectomy attenuates the progression of the obesity modulating pancreas functions in MSG-obese rats.
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Affiliation(s)
- Nayara de Carvalho Leite
- Department of Structural and Functional Biology, Institute of Biology, UNICAMP, Campinas, São Paulo, Brazil.
| | | | - Stefani Valéria Fisher
- Department of General Biology, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil
| | | | - Júlio Cezar de Oliveira
- Department of Biotechnology, Genetics and Cell Biology, State University of Maringa, Maringa, Parana, Brazil
| | | | - Carla Cristine Kanunfre
- Department of General Biology, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil
| | - Kleber Luiz Araujo Souza
- Institute of Biophysics Carlos Chagas Filho (IBCCF/Polo Xerém), Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Brazil
| | - Sabrina Grassiolli
- Department of General Biology, State University of Ponta Grossa, Ponta Grossa, Parana, Brazil
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22
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Ljubicic S, Polak K, Fu A, Wiwczar J, Szlyk B, Chang Y, Alvarez-Perez JC, Bird GH, Walensky LD, Garcia-Ocaña A, Danial NN. Phospho-BAD BH3 mimicry protects β cells and restores functional β cell mass in diabetes. Cell Rep 2015; 10:497-504. [PMID: 25640178 DOI: 10.1016/j.celrep.2014.12.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 11/21/2014] [Accepted: 12/26/2014] [Indexed: 12/31/2022] Open
Abstract
Strategies that simultaneously enhance the survival and glucose responsiveness of insulin-producing β cells will greatly augment β cell replacement therapies in type 1 diabetes (T1D). We show that genetic and pharmacologic mimetics of the phosphorylated BCL-2 homology 3 (BH3) domain of BAD impart β-cell-autonomous protective effects in the face of stress stimuli relevant to β cell demise in T1D. Importantly, these benefits translate into improved engraftment of donor islets in transplanted diabetic mice, increased β cell viability in islet grafts, restoration of insulin release, and diabetes reversal. Survival of β cells in this setting is not merely due to the inability of phospho-BAD to suppress prosurvival BCL-2 proteins but requires its activation of the glucose-metabolizing enzyme glucokinase. Thus, BAD phospho-BH3 mimetics may prove useful in the restoration of functional β cell mass in diabetes.
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Affiliation(s)
- Sanda Ljubicic
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Klaudia Polak
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Accalia Fu
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jessica Wiwczar
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Benjamin Szlyk
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Yigang Chang
- Division of Endocrinology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Juan C Alvarez-Perez
- Diabetes, Obesity and Metabolism Institute, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Gregory H Bird
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, MA 02115, USA
| | - Loren D Walensky
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Boston Children's Hospital, Boston, MA 02115, USA
| | - Adolfo Garcia-Ocaña
- Diabetes, Obesity and Metabolism Institute, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nika N Danial
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA.
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23
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Antonucci S, Tagliavini A, Pedersen MG. Reactive oxygen and nitrogen species disturb Ca(2+) oscillations in insulin-secreting MIN6 β-cells. Islets 2015; 7:e1107255. [PMID: 26732126 PMCID: PMC4878267 DOI: 10.1080/19382014.2015.1107255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Disturbances in pulsatile insulin secretion and Ca(2+) oscillations in pancreatic β-cells are early markers of diabetes, but the underlying mechanisms are still incompletely understood. Reactive oxygen/nitrogen species (ROS/RNS) are implicated in reduced β-cell function, and ROS/RNS target several Ca(2+) pumps and channels. Thus, we hypothesized that ROS/RNS could disturb Ca(2+) oscillations and downstream insulin pulsatility. We show that ROS/RNS production by photoactivation of aluminum phthalocyanine chloride (AlClPc) abolish or accelerate Ca(2+) oscillations in the MIN6 β-cell line, depending on the amount of ROS/RNS. Application of the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) inhibitor thapsigargin modifies the Ca(2+) response to high concentrations of ROS/RNS. Further, thapsigargin produces effects that resemble those elicited by moderate ROS/RNS production. These results indicate that ROS/RNS interfere with endoplasmic reticulum Ca(2+) handling. This idea is supported by theoretical studies using a mathematical model of Ca(2+) handling adapted to MIN6 cells. Our results suggest a putative link between ROS/RNS and disturbed pulsatile insulin secretion.
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Affiliation(s)
- Salvatore Antonucci
- Department of Biomedical Sciences; University of Padua; Padua, Italy
- Venetian Institute of Molecular Medicine; Padua, Italy
| | - Alessia Tagliavini
- Department of Information Engineering; University of Padua; Padua, Italy
| | - Morten Gram Pedersen
- Department of Information Engineering; University of Padua; Padua, Italy
- Correspondence to: Morten Gram Pedersen;
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Hasnain SZ, Borg DJ, Harcourt BE, Tong H, Sheng YH, Ng CP, Das I, Wang R, Chen ACH, Loudovaris T, Kay TW, Thomas HE, Whitehead JP, Forbes JM, Prins JB, McGuckin MA. Glycemic control in diabetes is restored by therapeutic manipulation of cytokines that regulate beta cell stress. Nat Med 2014; 20:1417-26. [PMID: 25362253 DOI: 10.1038/nm.3705] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 08/30/2014] [Indexed: 02/07/2023]
Abstract
In type 2 diabetes, hyperglycemia is present when an increased demand for insulin, typically due to insulin resistance, is not met as a result of progressive pancreatic beta cell dysfunction. This defect in beta cell activity is typically characterized by impaired insulin biosynthesis and secretion, usually accompanied by oxidative and endoplasmic reticulum (ER) stress. We demonstrate that multiple inflammatory cytokines elevated in diabetic pancreatic islets induce beta cell oxidative and ER stress, with interleukin-23 (IL-23), IL-24 and IL-33 being the most potent. Conversely, we show that islet-endogenous and exogenous IL-22, by regulating oxidative stress pathways, suppresses oxidative and ER stress caused by cytokines or glucolipotoxicity in mouse and human beta cells. In obese mice, antibody neutralization of IL-23 or IL-24 partially reduced beta cell ER stress and improved glucose tolerance, whereas IL-22 administration modulated oxidative stress regulatory genes in islets, suppressed ER stress and inflammation, promoted secretion of high-quality efficacious insulin and fully restored glucose homeostasis followed by restitution of insulin sensitivity. Thus, therapeutic manipulation of immune regulators of beta cell stress reverses the hyperglycemia central to diabetes pathology.
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Affiliation(s)
- Sumaira Z Hasnain
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Danielle J Borg
- Glycation &Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Brooke E Harcourt
- Glycation &Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Hui Tong
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Yonghua H Sheng
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Choa Ping Ng
- Metabolic Medicine Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Indrajit Das
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Ran Wang
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | - Alice C-H Chen
- Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia
| | | | - Thomas W Kay
- St. Vincent's Research Institute, Melbourne, Victoria, Australia
| | - Helen E Thomas
- St. Vincent's Research Institute, Melbourne, Victoria, Australia
| | - Jonathan P Whitehead
- 1] Metabolic Medicine Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia. [2] School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia
| | - Josephine M Forbes
- 1] Glycation &Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia. [2] School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Johannes B Prins
- 1] Metabolic Medicine Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia. [2] School of Medicine, University of Queensland, Brisbane, Queensland, Australia
| | - Michael A McGuckin
- 1] Mucosal Diseases Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia. [2] School of Biomedical Sciences, University of Queensland, Brisbane, Queensland, Australia. [3] School of Medicine, University of Queensland, Brisbane, Queensland, Australia
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Hajmrle C, Ferdaoussi M, Plummer G, Spigelman AF, Lai K, Manning Fox JE, MacDonald PE. SUMOylation protects against IL-1β-induced apoptosis in INS-1 832/13 cells and human islets. Am J Physiol Endocrinol Metab 2014; 307:E664-73. [PMID: 25139051 PMCID: PMC4200309 DOI: 10.1152/ajpendo.00168.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Posttranslational modification by the small ubiquitin-like modifier (SUMO) peptides, known as SUMOylation, is reversed by the sentrin/SUMO-specific proteases (SENPs). While increased SUMOylation reduces β-cell exocytosis, insulin secretion, and responsiveness to GLP-1, the impact of SUMOylation on islet cell survival is unknown. Mouse islets, INS-1 832/13 cells, or human islets were transduced with adenoviruses to increase either SENP1 or SUMO1 or were transfected with siRNA duplexes to knockdown SENP1. We examined insulin secretion, intracellular Ca²⁺ responses, induction of endoplasmic reticulum stress markers and inducible nitric oxide synthase (iNOS) expression, and apoptosis by TUNEL and caspase 3 cleavage. Surprisingly, upregulation of SENP1 reduces insulin secretion and impairs intracellular Ca²⁺ handling. This secretory dysfunction is due to SENP1-induced cell death. Indeed, the detrimental effect of SENP1 on secretory function is diminished when two mediators of β-cell death, iNOS and NF-κB, are pharmacologically inhibited. Conversely, enhanced SUMOylation protects against IL-1β-induced cell death. This is associated with reduced iNOS expression, cleavage of caspase 3, and nuclear translocation of NF-κB. Taken together, these findings identify SUMO1 as a novel antiapoptotic protein in islets and demonstrate that reduced viability accounts for impaired islet function following SENP1 up-regulation.
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Affiliation(s)
- Catherine Hajmrle
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Gregory Plummer
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Aliya F Spigelman
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Krista Lai
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Jocelyn E Manning Fox
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
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26
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Wang X, Lei XG, Wang J. Malondialdehyde regulates glucose-stimulated insulin secretion in murine islets via TCF7L2-dependent Wnt signaling pathway. Mol Cell Endocrinol 2014; 382:8-16. [PMID: 24035868 DOI: 10.1016/j.mce.2013.09.003] [Citation(s) in RCA: 209] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 08/30/2013] [Accepted: 09/03/2013] [Indexed: 11/29/2022]
Abstract
Evidence showed strong relations between malondialdehyde (MDA) levels and different pathological stages of diabetes. Here, an explicit system with freshly isolated islets and precisely controlled MDA gradient was employed to investigate the physiological effect of MDA on GSIS. Promoter analysis, pathway mapping, Q-PCR profiling, and siRNA verification were performed to clarify the intracellular signaling pathways. MDA at a moderately high level (5 and 10μM) promoted GSIS and accompanied with ATP/ADP ratio, cytosolic Ca(2+) level, and key regulators (GK, GLUT2, PDX1, and UCP2) changes in islets. Both upstream (PI3K and p-AKT) and downstream (TCF7L2 and TCF7) factors of Wnt pathway showed greatest changes. Knockdown of TCF7L2 blocked the MDA-induced GSIS elevation. These results indicated that MDA acted as a signaling messenger and regulated islet GSIS mainly through Wnt pathway. Therefore, the elevated MDA level and up-regulated Wnt signaling pathway could be an etiological factor in the development of hyperinsulinemia and type 2 diabetes.
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Affiliation(s)
- Xinhui Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China; Animal Science Department, Cornell University, Ithaca, NY 14853, USA
| | - Xin Gen Lei
- Animal Science Department, Cornell University, Ithaca, NY 14853, USA.
| | - Jufang Wang
- School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, Guangdong 510006, China.
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27
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Kurohane Kaneko Y, Ishikawa T. Dual role of nitric oxide in pancreatic β-cells. J Pharmacol Sci 2013; 123:295-300. [PMID: 24285083 DOI: 10.1254/jphs.13r10cp] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
An involvement of inducible nitric oxide (NO) synthase (NOS) in pancreatic β-cell degeneration during the process of type 1 diabetes has been well discussed. Recently, there is growing evidence for pivotal roles of constitutive NOS (cNOS) in β-cells; the presence of NOS1 and NOS3 in pancreatic β-cells and the effects of low-concentration NO, which is assumed to be derived from cNOS, on β-cell functions have been reported. However, the roles of cNOS-derived NO in β-cells are still under debate. One of the reasons seems to be that NO has multiple biological activities, which are dependent on its concentration. In β-cells, NO has been shown to exert positive and negative regulation of insulin secretion and anti- and pro-apoptotic activities, which is likely to be dependent on concentrations. In this review article, we will describe the current understanding of the roles of NO in pancreatic β-cells, especially focusing on cNOS-derived NO and its differential roles depending on concentrations.
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Affiliation(s)
- Yukiko Kurohane Kaneko
- Department of Pharmacology, School of Pharmaceutical Sciences, University of Shizuoka, Japan
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Beck A, Vinik Y, Shatz-Azoulay H, Isaac R, Streim S, Jona G, Boura-Halfon S, Zick Y. Otubain 2 is a novel promoter of beta cell survival as revealed by siRNA high-throughput screens of human pancreatic islets. Diabetologia 2013; 56:1317-26. [PMID: 23515685 DOI: 10.1007/s00125-013-2889-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 02/28/2013] [Indexed: 12/19/2022]
Abstract
AIMS/HYPOTHESIS Pro-inflammatory cytokines induce death of beta cells and hamper engraftment of transplanted islet mass. Our aim was to reveal novel genes involved in this process, as a platform for innovative therapeutic approaches. METHODS Small interfering RNA (siRNA) high-throughput screening (HTS) of primary human islets was employed to identify novel genes involved in cytokine-induced beta cell apoptosis. Dispersed human islets from nine human donors, treated with a combination of TNF-α, IL-1β and IFN-γ were transfected with ∼730 different siRNAs. Caspase-3/7 activity was measured, results were analysed and potential anti- and pro-apoptotic genes were identified. RESULTS Dispersed human pancreatic islets appeared to be suitable targets for performance of siRNA HTS. Using this methodology we found a number of potential pro- and anti-apoptotic target hits that have not been previously associated with pancreatic beta cell death. One such hit was the de-ubiquitinating enzyme otubain 2 (OTUB2). OTUB2 knockdown increased caspase-3/7 activity in MIN6 cells and primary human islets and inhibited insulin secretion and increased nuclear factor-κB (NF-κB) activity both under basal conditions and following cytokine treatment. CONCLUSIONS Use of dispersed human islets provides a new platform for functional HTS in a highly physiological system. Employing this technique enabled the identification of OTUB2 as a novel promoter of viability and insulin secretion in human beta cells. OTUB2 acts through the inhibition of NF-κB signalling, which is deleterious to beta cell survival. siRNA screens of human islets may therefore identify new targets, such as OTUB2, for therapeutic intervention in type 1 diabetes and islet transplantation.
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Affiliation(s)
- A Beck
- Department of Molecular Cell Biology, Weizmann Institute of Science, 234 Herzl Street, Rehovot 76100, Israel
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