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Dai Z, Ben-Younis A, Vlachaki A, Raleigh D, Thalassinos K. Understanding the structural dynamics of human islet amyloid polypeptide: Advancements in and applications of ion-mobility mass spectrometry. Biophys Chem 2024; 312:107285. [PMID: 38941872 PMCID: PMC11260546 DOI: 10.1016/j.bpc.2024.107285] [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: 01/19/2024] [Revised: 05/30/2024] [Accepted: 06/23/2024] [Indexed: 06/30/2024]
Abstract
Human islet amyloid polypeptide (hIAPP) forms amyloid deposits that contribute to β-cell death in pancreatic islets and are considered a hallmark of Type II diabetes Mellitus (T2DM). Evidence suggests that the early oligomers of hIAPP formed during the aggregation process are the primary pathological agent in islet amyloid induced β-cell death. The self-assembly mechanism of hIAPP, however, remains elusive, largely due to limitations in conventional biophysical techniques for probing the distribution or capturing detailed structures of the early, structurally dynamic oligomers. The advent of Ion-mobility Mass Spectrometry (IM-MS) has enabled the characterisation of hIAPP early oligomers in the gas phase, paving the way towards a deeper understanding of the oligomerisation mechanism and the correlation of structural information with the cytotoxicity of the oligomers. The sensitivity and the rapid structural characterisation provided by IM-MS also show promise in screening hIAPP inhibitors, categorising their modes of inhibition through "spectral fingerprints". This review delves into the application of IM-MS to the dissection of the complex steps of hIAPP oligomerisation, examining the inhibitory influence of metal ions, and exploring the characterisation of hetero-oligomerisation with different hIAPP variants. We highlight the potential of IM-MS as a tool for the high-throughput screening of hIAPP inhibitors, and for providing insights into their modes of action. Finally, we discuss advances afforded by recent advancements in tandem IM-MS and the combination of gas phase spectroscopy with IM-MS, which promise to deliver a more sensitive and higher-resolution structural portrait of hIAPP oligomers. Such information may help facilitate a new era of targeted therapeutic strategies for islet amyloidosis in T2DM.
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Affiliation(s)
- Zijie Dai
- Institute of Structural and Molecular Biology, Division of Bioscience, University College London, London WC1E 6BT, UK
| | - Aisha Ben-Younis
- Institute of Structural and Molecular Biology, Division of Bioscience, University College London, London WC1E 6BT, UK
| | - Anna Vlachaki
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge CB2 0PY, UK
| | - Daniel Raleigh
- Institute of Structural and Molecular Biology, Division of Bioscience, University College London, London WC1E 6BT, UK; Department of Chemistry, Stony Brook University, 100 Nicolls Road, Stony Brook, New York 11794, United States.
| | - Konstantinos Thalassinos
- Institute of Structural and Molecular Biology, Division of Bioscience, University College London, London WC1E 6BT, UK; Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, UK.
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Yeo HJ, Shin MJ, Yoo KY, Jung BH, Eum WS, Choi SY. Tat-CIAPIN1 Prevents Pancreatic β-Cell Death in hIAPP-Induced RINm5F Cells and T2DM Animal Model. Int J Mol Sci 2023; 24:10478. [PMID: 37445656 DOI: 10.3390/ijms241310478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
It is well known that the cytokine-induced apoptosis inhibitor 1 (CIAPIN1) protein plays an important role in biological progresses as an anti-apoptotic protein. Human islet amyloid peptide (hIAPP), known as amylin, is caused to pancreatic β-cell death in type 2 diabetes mellitus (T2DM). However, the function of CIAPIN1 protein on T2DM is not yet well studied. Therefore, we investigated the effects of CIAPIN1 protein on a hIAPP-induced RINm5F cell and T2DM animal model induced by a high-fat diet (HFD) and streptozotocin (STZ). The Tat-CIAPIN1 protein reduced the activation of mitogen-activated protein kinase (MAPK) and regulated the apoptosis-related protein expression levels including COX-2, iNOS, Bcl-2, Bax, and Caspase-3 in hIAPP-induced RINm5F cells. In a T2DM mice model, the Tat-CIAPIN1 protein ameliorated the pathological changes of pancreatic β-cells and reduced the fasting blood glucose, body weight and hemoglobin Alc (HbAlc) levels. In conclusion, the Tat-CIAPIN1 protein showed protective effects against T2DM by protection of β-cells via inhibition of hIAPP toxicity and by regulation of a MAPK signal pathway, suggesting CIAPIN1 protein can be a therapeutic protein drug candidate by beneficial regulation of T2DM.
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Affiliation(s)
- Hyeon Ji Yeo
- Department of Biomedical Science and Research, Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Min Jea Shin
- Department of Biomedical Science and Research, Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Ki-Yeon Yoo
- Department of Anatomy, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
| | - Bo Hyun Jung
- Department of Anatomy, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Republic of Korea
| | - Won Sik Eum
- Department of Biomedical Science and Research, Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
| | - Soo Young Choi
- Department of Biomedical Science and Research, Institute of Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Republic of Korea
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Lee JH, Lee J. Endoplasmic Reticulum (ER) Stress and Its Role in Pancreatic β-Cell Dysfunction and Senescence in Type 2 Diabetes. Int J Mol Sci 2022; 23:ijms23094843. [PMID: 35563231 PMCID: PMC9104816 DOI: 10.3390/ijms23094843] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 04/22/2022] [Accepted: 04/26/2022] [Indexed: 02/07/2023] Open
Abstract
An increased life span and accompanying nutritional affluency have led to a rapid increase in diseases associated with aging, such as obesity and type 2 diabetes, imposing a tremendous economic and health burden on society. Pancreatic β-cells are crucial for controlling glucose homeostasis by properly producing and secreting the glucose-lowering hormone insulin, and the dysfunction of β-cells determines the outcomes for both type 1 and type 2 diabetes. As the native structure of insulin is formed within the endoplasmic reticulum (ER), ER homeostasis should be appropriately maintained to allow for the proper metabolic homeostasis and functioning of β-cells. Recent studies have found that cellular senescence is critically linked with cellular stresses, including ER stress, oxidative stress, and mitochondrial stress. These studies implied that β-cell senescence is caused by ER stress and other cellular stresses and contributes to β-cells’ dysfunction and the impairment of glucose homeostasis. This review documents and discusses the current understanding of cellular senescence, β-cell function, ER stress, its associated signaling mechanism (unfolded protein response), and the effect of ER stress on β-cell senescence and dysfunction.
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Affiliation(s)
- Ji-Hye Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
| | - Jaemin Lee
- Department of New Biology, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- New Biology Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Well Aging Research Center, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea
- Correspondence:
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The Use of Bioactive Compounds in Hyperglycemia- and Amyloid Fibrils-Induced Toxicity in Type 2 Diabetes and Alzheimer’s Disease. Pharmaceutics 2022; 14:pharmaceutics14020235. [PMID: 35213966 PMCID: PMC8879577 DOI: 10.3390/pharmaceutics14020235] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/19/2022] [Indexed: 12/29/2022] Open
Abstract
It has become increasingly apparent that defective insulin signaling may increase the risk for developing Alzheimer’s disease (AD), influence neurodegeneration through promotion of amyloid formation or by increasing inflammatory responses to intraneuronal β-amyloid. Recent work has demonstrated that hyperglycemia is linked to cognitive decline, with elevated levels of glucose causing oxidative stress in vulnerable tissues such as the brain. The ability of β-amyloid peptide to form β-sheet-rich aggregates and induce apoptosis has made amyloid fibrils a leading target for the development of novel pharmacotherapies used in managing and treatment of neuropathological conditions such as AD-related cognitive decline. Additionally, deposits of β-sheets folded amylin, a glucose homeostasis regulator, are also present in diabetic patients. Thus, therapeutic compounds capable of reducing intracellular protein aggregation in models of neurodegenerative disorders may prove useful in ameliorating type 2 diabetes mellitus symptoms. Furthermore, both diabetes and neurodegenerative conditions, such as AD, are characterized by chronic inflammatory responses accompanied by the presence of dysregulated inflammatory biomarkers. This review presents current evidence describing the role of various small bioactive molecules known to ameliorate amyloidosis and subsequent effects in prevention and development of diabetes and AD. It also highlights the potential efficacy of peptide–drug conjugates capable of targeting intracellular targets.
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Nie T, Cooper GJS. Mechanisms Underlying the Antidiabetic Activities of Polyphenolic Compounds: A Review. Front Pharmacol 2021; 12:798329. [PMID: 34970150 PMCID: PMC8712966 DOI: 10.3389/fphar.2021.798329] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/18/2021] [Indexed: 12/16/2022] Open
Abstract
Polyphenolic compounds are thought to show considerable promise for the treatment of various metabolic disorders, including type 2 diabetes mellitus (T2DM). This review addresses evidence from in vitro, in vivo, and clinical studies for the antidiabetic effects of certain polyphenolic compounds. We focus on the role of cytotoxic human amylin (hA) aggregates in the pathogenesis of T2DM, and how polyphenols can ameliorate this process by suppressing or modifying their formation. Small, soluble amylin oligomers elicit cytotoxicity in pancreatic islet β-cells and may thus cause β-cell disruption in T2DM. Amylin oligomers may also contribute to oxidative stress and inflammation that lead to the triggering of β-cell apoptosis. Polyphenols may exert antidiabetic effects via their ability to inhibit hA aggregation, and to modulate oxidative stress, inflammation, and other pathways that are β-cell-protective or insulin-sensitizing. There is evidence that their ability to inhibit and destabilize self-assembly by hA requires aromatic molecular structures that bind to misfolding monomers or oligomers, coupled with adjacent hydroxyl groups present on single phenyl rings. Thus, these multifunctional compounds have the potential to be effective against the pleiotropic mechanisms of T2DM. However, substantial further research will be required before it can be determined whether a polyphenol-based molecular entity can be used as a therapeutic for type 2 diabetes.
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Affiliation(s)
- Tina Nie
- School of Biological Sciences, Faculty of Science, the University of Auckland, Auckland, New Zealand
| | - Garth J. S. Cooper
- School of Biological Sciences, Faculty of Science, the University of Auckland, Auckland, New Zealand
- The Maurice Wilkins Centre for Molecular Biodiscovery, Faculty of Science, the University of Auckland, Auckland, New Zealand
- Centre for Advanced Discovery and Experimental Therapeutics, Division of Cardiovascular Sciences, Faculty of Biology Medicine & Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
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Marmentini C, Branco RCS, Boschero AC, Kurauti MA. Islet amyloid toxicity: From genesis to counteracting mechanisms. J Cell Physiol 2021; 237:1119-1142. [PMID: 34636428 DOI: 10.1002/jcp.30600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 09/09/2021] [Accepted: 10/01/2021] [Indexed: 11/11/2022]
Abstract
Islet amyloid polypeptide (IAPP or amylin) is a hormone co-secreted with insulin by pancreatic β-cells and is the major component of islet amyloid. Islet amyloid is found in the pancreas of patients with type 2 diabetes (T2D) and may be involved in β-cell dysfunction and death, observed in this disease. Thus, investigating the aspects related to amyloid formation is relevant to the development of strategies towards β-cell protection. In this sense, IAPP misprocessing, IAPP overproduction, and disturbances in intra- and extracellular environments seem to be decisive for IAPP to form islet amyloid. Islet amyloid toxicity in β-cells may be triggered in intra- and/or extracellular sites by membrane damage, endoplasmic reticulum stress, autophagy disruption, mitochondrial dysfunction, inflammation, and apoptosis. Importantly, different approaches have been suggested to prevent islet amyloid cytotoxicity, from inhibition of IAPP aggregation to attenuation of cell death mechanisms. Such approaches have improved β-cell function and prevented the development of hyperglycemia in animals. Therefore, counteracting islet amyloid may be a promising therapy for T2D treatment.
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Affiliation(s)
- Carine Marmentini
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Renato C S Branco
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Antonio C Boschero
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Mirian A Kurauti
- Laboratory of Endocrine Pancreas and Metabolism, Obesity and Comorbidities Research Center (OCRC), University of Campinas (UNICAMP), Campinas, Brazil.,Department of Physiological Sciences, Biological Sciences Center, State University of Maringa (UEM), Maringa, Brazil
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Karunakaran U, Elumalai S, Moon JS, Won KC. CD36 Signal Transduction in Metabolic Diseases: Novel Insights and Therapeutic Targeting. Cells 2021; 10:cells10071833. [PMID: 34360006 PMCID: PMC8305429 DOI: 10.3390/cells10071833] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/14/2021] [Accepted: 07/17/2021] [Indexed: 12/24/2022] Open
Abstract
The cluster of differentiation 36 (CD36) is a scavenger receptor present on various types of cells and has multiple biological functions that may be important in inflammation and in the pathogenesis of metabolic diseases, including diabetes. Here, we consider recent insights into how the CD36 response becomes deregulated under metabolic conditions, as well as the therapeutic benefits of CD36 inhibition, which may provide clues for developing strategies aimed at the treatment or prevention of diabetes associated with metabolic diseases. To facilitate this process further, it is important to pinpoint regulatory mechanisms that are relevant under physiological and pathological conditions. In particular, understanding the mechanisms involved in dictating specific CD36 downstream cellular outcomes will aid in the discovery of potent compounds that target specific CD36 downstream signaling cascades.
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Affiliation(s)
- Udayakumar Karunakaran
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
| | - Suma Elumalai
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
| | - Jun-Sung Moon
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
- Yeungnam University College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.M.); +82-53-620-3846 (K.-C.W.)
| | - Kyu-Chang Won
- Innovative Center for Aging Research, Yeungnam University Medical Center, Daegu 42415, Korea; (U.K.); (S.E.)
- Yeungnam University College of Medicine, Daegu 42415, Korea
- Correspondence: (J.-S.M.); (K.-C.W.); Tel.: +82-53-620-3825 (J.-S.M.); +82-53-620-3846 (K.-C.W.)
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Mechanisms of Beta-Cell Apoptosis in Type 2 Diabetes-Prone Situations and Potential Protection by GLP-1-Based Therapies. Int J Mol Sci 2021; 22:ijms22105303. [PMID: 34069914 PMCID: PMC8157542 DOI: 10.3390/ijms22105303] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by chronic hyperglycemia secondary to the decline of functional beta-cells and is usually accompanied by a reduced sensitivity to insulin. Whereas altered beta-cell function plays a key role in T2D onset, a decreased beta-cell mass was also reported to contribute to the pathophysiology of this metabolic disease. The decreased beta-cell mass in T2D is, at least in part, attributed to beta-cell apoptosis that is triggered by diabetogenic situations such as amyloid deposits, lipotoxicity and glucotoxicity. In this review, we discussed the molecular mechanisms involved in pancreatic beta-cell apoptosis under such diabetes-prone situations. Finally, we considered the molecular signaling pathways recruited by glucagon-like peptide-1-based therapies to potentially protect beta-cells from death under diabetogenic situations.
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Hsu JY, Rao Sathyan A, Hsu KC, Chen LC, Yen CC, Tseng HJ, Wu KC, Liu HK, Huang WJ. Synthesis of Yakuchinone B-Inspired Inhibitors against Islet Amyloid Polypeptide Aggregation. JOURNAL OF NATURAL PRODUCTS 2021; 84:1096-1103. [PMID: 33600175 DOI: 10.1021/acs.jnatprod.0c01162] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Type 2 diabetes mellitus (T2DM) is associated with pancreatic β-cell dysfunction and insulin resistance. Islet amyloid polypeptide (IAPP) aggregation is found to induce islet β-cell death in T2DM patients. Recently, we demonstrated that yakuchinone B derivative 1 exhibited inhibitory activity against IAPP aggregation. Thus, in this study, a series of synthesized yakuchinone B-inspired compounds were tested for their anti-IAPP aggregation activity. Four of these compounds, 4e-h, showed greater activity than the lead compound 1, in the sub-μM range (IC50 = 0.7-0.8 μM). The molecular docking analysis revealed crucial hydrogen bonds between the compounds and residues S19 and N22 and important hydrophobic interactions with residue I26. Notably, compounds 4g and 4h significantly protected β-cells against IAPP-induced toxicity with EC50 values of 0.1 and 0.2 μM, respectively. In contrast, the protective activities of compounds 4e and 4f were weak. Overall, these results suggest that the compounds exhibiting IAPP aggregation-inhibiting activity have the potential to treat T2DM.
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Affiliation(s)
- Jui-Yi Hsu
- Ph.D. Program for Cancer Molecular Biology and Drug Discovery, Taipei Medical University, Taipei 110, Taiwan
| | - Ashish Rao Sathyan
- Ph D. Program in the Clinical Drug Development of Herbal Medicine, Taipei Medical University, Taipei 110, Taiwan
| | - Kai-Cheng Hsu
- Ph.D. Program for Cancer Molecular Biology and Drug Discovery, Taipei Medical University, Taipei 110, Taiwan
| | - Liang-Chieh Chen
- Ph.D. Program for Cancer Molecular Biology and Drug Discovery, Taipei Medical University, Taipei 110, Taiwan
| | - Cheng-Chung Yen
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei 110, Taiwan
| | - Hui-Ju Tseng
- Ph.D. Program in Drug Discovery and Development Industry, Taipei Medical University, Taipei 110, Taiwan
| | - Kun-Chang Wu
- School of Pharmacy, China Medical University, Taichung 404, Taiwan
| | - Hui-Kang Liu
- Ph D. Program in the Clinical Drug Development of Herbal Medicine, Taipei Medical University, Taipei 110, Taiwan
- National Research Institute of Chinese Medicine, Ministry of Health and Welfare, Taipei, Taiwan
| | - Wei-Jan Huang
- Ph D. Program in the Clinical Drug Development of Herbal Medicine, Taipei Medical University, Taipei 110, Taiwan
- Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei 110, Taiwan
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Zhu M, Liu X, Liu W, Lu Y, Cheng J, Chen Y. β cell aging and age-related diabetes. Aging (Albany NY) 2021; 13:7691-7706. [PMID: 33686020 PMCID: PMC7993693 DOI: 10.18632/aging.202593] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/23/2020] [Indexed: 02/05/2023]
Abstract
Type 2 diabetes is characterized by insulin resistance and loss of β cell mass and function. Aging is considered as a major risk factor for development of type 2 diabetes. However, the roles of pancreatic β cell senescence and systemic aging in the pathogenesis of type 2 diabetes in elderly people remain poorly understood. In this review, we aimed to discuss the current findings and viewpoints focusing on β cell aging and the development of type 2 diabetes.
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Affiliation(s)
- Min Zhu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Xiaohong Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Wen Liu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Yanrong Lu
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Jingqiu Cheng
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, P.R. China
| | - Younan Chen
- Key Laboratory of Transplant Engineering and Immunology, NHFPC, Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, P.R. China
- Institutes for Systems Genetics, Frontiers Science Center for Disease-related Molecular Network, West China Hospital, Sichuan University, Chengdu, P.R. China
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Engin AB, Engin A. Protein Kinases Signaling in Pancreatic Beta-cells Death and Type 2 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:195-227. [PMID: 33539017 DOI: 10.1007/978-3-030-49844-3_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Type 2 diabetes (T2D) is a worldwide serious public health problem. Insulin resistance and β-cell failure are the two major components of T2D pathology. In addition to defective endoplasmic reticulum (ER) stress signaling due to glucolipotoxicity, β-cell dysfunction or β-cell death initiates the deleterious vicious cycle observed in T2D. Although the primary cause is still unknown, overnutrition that contributes to the induction of the state of low-grade inflammation, and the activation of various protein kinases-related metabolic pathways are main factors leading to T2D. In this chapter following subjects, which have critical checkpoints regarding β-cell fate and protein kinases pathways are discussed; hyperglycemia-induced β-cell failure, chronic accumulation of unfolded protein in β-cells, the effect of intracellular reactive oxygen species (ROS) signaling to insulin secretion, excessive saturated free fatty acid-induced β-cell apoptosis, mitophagy dysfunction, proinflammatory responses and insulin resistance, and the reprogramming of β-cell for differentiation or dedifferentiation in T2D. There is much debate about selecting proposed therapeutic strategies to maintain or enhance optimal β-cell viability for adequate insulin secretion in T2D. However, in order to achieve an effective solution in the treatment of T2D, more intensive clinical trials are required on newer therapeutic options based on protein kinases signaling pathways.
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Affiliation(s)
- Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara, Turkey.
| | - Atilla Engin
- Department of General Surgery, Faculty of Medicine, Gazi University, Ankara, Turkey
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12
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Saghir AE, Farrugia G, Vassallo N. The human islet amyloid polypeptide in protein misfolding disorders: Mechanisms of aggregation and interaction with biomembranes. Chem Phys Lipids 2020; 234:105010. [PMID: 33227292 DOI: 10.1016/j.chemphyslip.2020.105010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/06/2020] [Accepted: 11/09/2020] [Indexed: 02/09/2023]
Abstract
Human islet amyloid polypeptide (hIAPP), otherwise known as amylin, is a 37-residue peptide hormone which is reported to be a common factor in protein misfolding disorders such as type-2 diabetes mellitus, Alzheimer's disease and Parkinson's disease, due to deposition of insoluble hIAPP amyloid in the pancreas and brain. Multiple studies point to the importance of the peptide's interaction with biological membranes and the cytotoxicity of hIAPP species. Here, we discuss the aggregation pathways of hIAPP amyloid fibril formation and focus on the complex interplay between membrane-mediated assembly of hIAPP and the associated mechanisms of membrane damage caused by the peptide species. Mitochondrial membranes, which are unique in their lipid composition, are proposed as prime targets for the early intracellular formation of hIAPP toxic entities. We suggest that future studies should include more physiologically-relevant and in-cell studies to allow a more accurate model of in vivo interactions. Finally, we underscore an urgent need for developing effective therapeutic strategies aimed at hindering hIAPP-phospholipid interactions.
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Affiliation(s)
- Adam El Saghir
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Gianluca Farrugia
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Neville Vassallo
- Dept. of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta.
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Kassouf T, Sumara G. Impact of Conventional and Atypical MAPKs on the Development of Metabolic Diseases. Biomolecules 2020; 10:biom10091256. [PMID: 32872540 PMCID: PMC7563211 DOI: 10.3390/biom10091256] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/25/2020] [Accepted: 08/26/2020] [Indexed: 02/06/2023] Open
Abstract
The family of mitogen-activated protein kinases (MAPKs) consists of fourteen members and has been implicated in regulation of virtually all cellular processes. MAPKs are divided into two groups, conventional and atypical MAPKs. Conventional MAPKs are further classified into four sub-families: extracellular signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK1, 2 and 3), p38 (α, β, γ, δ), and extracellular signal-regulated kinase 5 (ERK5). Four kinases, extracellular signal-regulated kinase 3, 4, and 7 (ERK3, 4 and 7) as well as Nemo-like kinase (NLK) build a group of atypical MAPKs, which are activated by different upstream mechanisms than conventional MAPKs. Early studies identified JNK1/2 and ERK1/2 as well as p38α as a central mediators of inflammation-evoked insulin resistance. These kinases have been also implicated in the development of obesity and diabetes. Recently, other members of conventional MAPKs emerged as important mediators of liver, skeletal muscle, adipose tissue, and pancreatic β-cell metabolism. Moreover, latest studies indicate that atypical members of MAPK family play a central role in the regulation of adipose tissue function. In this review, we summarize early studies on conventional MAPKs as well as recent findings implicating previously ignored members of the MAPK family. Finally, we discuss the therapeutic potential of drugs targeting specific members of the MAPK family.
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Hogan MF, Ziemann M, K N H, Rodriguez H, Kaspi A, Esser N, Templin AT, El-Osta A, Kahn SE. RNA-seq-based identification of Star upregulation by islet amyloid formation. Protein Eng Des Sel 2020; 32:67-76. [PMID: 31504890 DOI: 10.1093/protein/gzz022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 06/24/2019] [Accepted: 07/05/2019] [Indexed: 12/26/2022] Open
Abstract
Aggregation of islet amyloid polypeptide (IAPP) into islet amyloid results in β-cell toxicity in human type 2 diabetes. To determine the effect of islet amyloid formation on gene expression, we performed ribonucleic acid (RNA) sequencing (RNA-seq) analysis using cultured islets from either wild-type mice (mIAPP), which are not amyloid prone, or mice that express human IAPP (hIAPP), which develop amyloid. Comparing mIAPP and hIAPP islets, 5025 genes were differentially regulated (2439 upregulated and 2586 downregulated). When considering gene sets (reactomes), 248 and 52 pathways were up- and downregulated, respectively. Of the top 100 genes upregulated under two conditions of amyloid formation, seven were common. Of these seven genes, only steroidogenic acute regulatory protein (Star) demonstrated no effect of glucose per se to modify its expression. We confirmed this differential gene expression using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and also demonstrated the presence of STAR protein in islets containing amyloid. Furthermore, Star is a part of reactomes representing metabolism, metabolism of lipids, metabolism of steroid hormones, metabolism of steroids and pregnenolone biosynthesis. Thus, examining gene expression that is differentially regulated by islet amyloid has the ability to identify new molecules involved in islet physiology and pathology applicable to type 2 diabetes.
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Affiliation(s)
- Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA 98018, USA
| | - Mark Ziemann
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC 3004, Australia
| | - Harikrishnan K N
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC 3004, Australia
| | - Hanah Rodriguez
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC 3004, Australia
| | - Antony Kaspi
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC 3004, Australia
| | - Nathalie Esser
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA 98018, USA
| | - Andrew T Templin
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA 98018, USA
| | - Assam El-Osta
- Epigenetics in Human Health and Disease, Department of Diabetes, Monash University, Melbourne, VIC 3004, Australia.,Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, The Chinese University of Hong Kong, 3/F Lui Che Woo Clinical Sciences Building, 30-32 Ngan Shing Street, Sha Tin, Hong Kong SAR.,University College Copenhagen, Faculty of Health, Department of Technology, Biomedical Laboratory Science, Copenhagen, Denmark
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA 98018, USA
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Alpha1-antitrypsin ameliorates islet amyloid-induced glucose intolerance and β-cell dysfunction. Mol Metab 2020; 37:100984. [PMID: 32229246 PMCID: PMC7186564 DOI: 10.1016/j.molmet.2020.100984] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 03/21/2020] [Indexed: 02/07/2023] Open
Abstract
Objective Pancreatic β-cell failure is central to the development and progression of type 2 diabetes (T2D). The aggregation of human islet amyloid polypeptide (hIAPP) has been associated with pancreatic islet inflammation and dysfunction in T2D. Alpha1-antitrypsin (AAT) is a circulating protease inhibitor with anti-inflammatory properties. Here, we sought to investigate the potential therapeutic effect of AAT treatment in a mouse model characterized by hIAPP overexpression in pancreatic β-cells. Methods Mice overexpressing hIAPP (hIAPP-Tg) in pancreatic β-cells were used as a model of amyloid-induced β-cell dysfunction. Glucose homeostasis was evaluated by glucose tolerance tests and insulin secretion assays. Apoptosis and amyloid formation was assessed in hIAPP-Tg mouse islets cultured at high glucose levels. Dissociated islet cells were cocultured with macrophages obtained from the peritoneal cavity. Results Nontreated hIAPP-Tg mice were glucose intolerant and exhibited impaired insulin secretion. Interestingly, AAT treatment improved glucose tolerance and restored the insulin secretory response to glucose in hIAPP-Tg mice. Moreover, AAT administration normalized the expression of the essential β-cell genes MafA and Pdx1, which were downregulated in pancreatic islets from hIAPP-Tg mice. AAT prevented the formation of amyloid deposits and apoptosis in hIAPP-Tg islets cultured at high glucose concentrations. Since islet macrophages mediate hIAPP-induced β-cell dysfunction, we investigated the effect of AAT in cocultures of macrophages and islet cells. AAT prevented hIAPP-induced β-cell apoptosis in these cocultures without reducing the hIAPP-induced secretion of IL-1β by macrophages. Remarkably, AAT protected β-cells against the cytotoxic effects of conditioned medium from hIAPP-treated macrophages. Similarly, AAT also abrogated the cytotoxic effects of exogenous proinflammatory cytokines on pancreatic β-cells. Conclusions These results demonstrate that treatment with AAT improves glucose homeostasis in mice overexpressing hIAPP and protects pancreatic β-cells from the cytotoxic actions of hIAPP mediated by macrophages. These results support the use of AAT-based therapies to recover pancreatic β-cell function for the treatment of T2D. Alpha1-antitrypsin (AAT) ameliorates glucose intolerance in hIAPP transgenic mice. AAT improves insulin secretion in hIAPP transgenic mice. AAT prevents apoptosis and amyloid deposition in cultured hIAPP transgenic islets. AAT protects β-cells from hIAPP-induced cytotoxicity mediated by macrophages. AAT abrogates the cytotoxic effects of proinflammatory cytokines on β-cells.
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Oligomannuronate prevents mitochondrial dysfunction induced by IAPP in RINm5F islet cells by inhibition of JNK activation and cell apoptosis. Chin Med 2020; 15:27. [PMID: 32226477 PMCID: PMC7092590 DOI: 10.1186/s13020-020-00310-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/13/2020] [Indexed: 01/09/2023] Open
Abstract
Background Oligomannuronates (OM) are natural products from alginate that is frequently used as food supplement. The aim of this study was to investigate the in vitro protective effects of OM on RINm5F cells against human Islet amyloid polypeptide (IAPP) induced mitochondrial dysfunction, as well as the underlying mechanisms. Methods In the present study, we obtained several kinds of OM with different molecular masses, and then we used RINm5F cells as a model to elucidate the involvement of JNK signal pathway in hIAPP-induced mitochondrial dysfunction in pancreatic beta cells, and the protective effects of OM are associated with its ability to attenuate the mitochondrial dysfunction. Results Our results demonstrated that human IAPP induced mitochondrial dysfunction, as evidence by loss of ΔΨm and ATP content, and decrease in oxygen consumption and complex activities, was accompanied by JNK activation, changes in the expressions of Bcl-2 and Bax proteins, release of cytochrome c (Cyto-c) and apoptosis inducing factor (AIF) from mitochondria into cytosol. Interestingly, the human IAPP induced damage in RINm5F cells were effectively restored by co-treatment of OM. Moreover, JNK activation was required for the OM mediated changes in RINm5F cells. Conclusions OM prevented mitochondrial dysfunction induced by human IAPP in RINm5F islet cells through JNK dependent signaling pathways.
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Targeting the IL-1β/IL-1Ra pathways for the aggregation of human islet amyloid polypeptide in an ex vivo organ culture system of the intervertebral disc. Exp Mol Med 2019; 51:1-16. [PMID: 31554783 PMCID: PMC6802624 DOI: 10.1038/s12276-019-0310-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/12/2019] [Accepted: 06/18/2019] [Indexed: 12/18/2022] Open
Abstract
Intervertebral disc degeneration (IDD) is characterized by excessive apoptosis of nucleus pulposus (NP) cells and hyperactive extracellular matrix (ECM) catabolism. Our previous studies revealed the relationship between human islet amyloid polypeptide (hIAPP) and NP cell apoptosis. However, the role of hIAPP aggregates in IDD has not yet been investigated. This study aimed to determine whether the accumulation of hIAPP aggregates promotes IDD progression. The aggregation of hIAPP increased in human NP tissues during IDD. The deposition of hIAPP aggravated the compression-induced IDD that promoted NP cell apoptosis and ECM degradation via IL-1β/IL-1Ra signaling in an ex vivo rat disc model. Moreover, neutralizing IL-1β augmented the protective effects of hIAPP overexpression by decreasing hIAPP aggregation in human NP cells. These results suggest that the aggregation of hIAPP promotes NP cell apoptosis and ECM degradation ex vivo and in vitro by disrupting the balance of IL-1β/IL-1Ra signaling.
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Li Y, Xia YZ, Hu SM, Kong LY, Yang L. Tooniliatone A sensitizes multidrug resistant cancer cells by decreasing Bcl-xL via activation of JNK MAPK signaling. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 62:152947. [PMID: 31102887 DOI: 10.1016/j.phymed.2019.152947] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/28/2019] [Accepted: 05/04/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Multidrug resistance (MDR) refers to the phenotype of tumor cells that are resistant to various chemotherapeutic drugs with different structures and functions, which is clearly disadvantageous for patients. Finding a natural product that can effectively reverse the MDR of tumor cells is important for the treatment of patients. PURPOSE To prove that tooniliatone A (TA), a novel typical limonoid, can effectively reverse the MDR of tumor cells and to explore its mechanism of action. METHODS The MTT, CCK-8 and monoclonal formation assays, as well as flow cytometry, were used to evaluate the role of TA in reversing tumor multidrug resistance; then the mechanism of action for TA was explored by western blotting and real-time fluorescent quantitative PCR. RESULTS TA significantly reversed the MDR of the K562/MDR and MCF-7/MDR cell lines. TA can inhibit the anti-apoptotic protein Bcl-xL to make cells sensitive to common chemotherapeutic drugs and activate the SAPK/JNK pathway to promote phosphorylation of JNK and its downstream cJun protein. Small interfering RNA-mediated knockdown of JNK and cJun could antagonize the MDR reversal effect of TA and the inhibition of Bcl-xL by TA. Therefore, we hypothesized that TA activates the JNK pathway to increase the transcription of the proapoptotic protein Bim, thereby inhibiting Bcl-xL and reversing MDR in tumor cells. CONCLUSION Our study suggests that TA reverses tumor MDR by activating the SAPK/JNK pathway to inhibit the action of Bcl-xL. TA may be an effective tumor MDR reversal agent.
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Affiliation(s)
- Yun Li
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nan Jing 210009, China
| | - Yuan-Zheng Xia
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nan Jing 210009, China
| | - Sheng-Mou Hu
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nan Jing 210009, China
| | - Ling-Yi Kong
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nan Jing 210009, China.
| | - Lei Yang
- Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines, China Pharmaceutical University, 24 Tong Jia Xiang, Nan Jing 210009, China.
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Tian H, Wang ZY. Zinc Chelator Inhibits Zinc-Induced Islet Amyloid Polypeptide Deposition and Apoptosis in INS-1 Cells. Biol Trace Elem Res 2019; 189:201-208. [PMID: 30027367 DOI: 10.1007/s12011-018-1444-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 07/12/2018] [Indexed: 12/16/2022]
Abstract
Amyloid deposition and beta cell apoptosis are characteristic pathological features of type 2 diabetes mellitus (DM). Islet amyloid polypeptide (IAPP) is the most abundant component of amyloid deposition. Monomeric IAPP does not form amyloid deposition, but the fibrous IAPP may aggregate and form amyloid deposits. Previous studies have shown that zinc is closely related to IAPP deposition through crosslink with monomeric IAPP into fibrous aggregates. In this study, we aimed to investigate whether chelating zinc could inhibit zinc-induced amyloid deposits and apoptosis of islet beta cell. N, N, N', N'-Tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) is a specific chelator of zinc, with membrane permeability. It could effectively reduce the concentration of intracellular zinc. So, we used TPEN to treat hIAPP-transfected INS-1 cells. By MTT assay, the concentration (1 μM) and incubation time (12 h) of TPEN without affecting cell viability were determined. The results showed that TPEN reduced zinc-induced IAPP deposition in the culture system. Furthermore, we analyzed the effect of zinc and TPEN on the apoptosis and insulin level. The results showed that TPEN could reverse zinc-induced INS-1 cell apoptosis and insulin secretion. And the anti-apoptosis effects of TPEN is related to extracellular regulated protein kinases (ERK)/c-jun N-terminal kinase (JNK) signaling pathway. The present data indicated that chelating zinc could inhibit zinc-induced amyloid deposition and beta cell apoptosis. Thus, maintaining zinc homeostasis in islet beta cell might become a useful strategy for DM therapy.
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Affiliation(s)
- He Tian
- Institute of Health Sciences, Key Laboratory of Medical Cell Biology of Ministry of education, China Medical University, Shenyang, 110122, People's Republic of China
- Department of Histology and Embryology, Jinzhou Medical University, Jinzhou, 121000, People's Republic of China
| | - Zhan-You Wang
- Institute of Health Sciences, Key Laboratory of Medical Cell Biology of Ministry of education, China Medical University, Shenyang, 110122, People's Republic of China.
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Lee T, Yun S, Jeong JH, Jung TW. Asprosin impairs insulin secretion in response to glucose and viability through TLR4/JNK-mediated inflammation. Mol Cell Endocrinol 2019; 486:96-104. [PMID: 30853600 DOI: 10.1016/j.mce.2019.03.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 01/02/2023]
Abstract
Severe inflammation in the islets is observed in obese patients with type 2 diabetes. Inflammation in the islets is caused by obesity-induced serum free fatty acids. Asprosin is a fasting-induced adipokine, which contributes to hepatic glucose production. However, the effects of asprosin on inflammation and cellular dysfunction in pancreatic β-cells remain to be elucidated. Here, we demonstrated that treatment of mouse insulinoma MIN6 cells and human primary islets containing β-cells with palmitate increased asprosin expression and secretion. Treatment of MIN6 cells and human primary islets with palmitate increased phosphorylation of the inflammatory marker nuclear factor-kappa B (NFκB) and the release of pro-inflammatory cytokines including TNF and MCP-1 and decreased glucose-stimulated insulin secretion and cell viability. However, siRNA-mediated suppression of asprosin reversed these changes. Recombinant asprosin treatment of MIN6 cells and human primary islets augmented the inflammation response, cellular dysfunction, and apoptosis in a dose-dependent manner. Asprosin induced toll-like receptor (TLR) 4 expression and JNK phosphorylation. siRNA for TLR4 or JNK mitigated the effects of asprosin on inflammation and cellular dysfunction. These results suggest that palmitate-derived asprosin secretion from β-cells results in their inflammation and dysfunction through a TLR4/JNK-mediated pathway. This report suggests asprosin as a novel therapeutic target for the treatment of type 2 diabetes through preservation of β-cell function.
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Affiliation(s)
- Taeseung Lee
- Department of Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, South Korea; Department of Surgery, Seoul National University College of Medicine, Seoul, South Korea
| | - Subin Yun
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY, USA
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, South Korea
| | - Tae Woo Jung
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul, South Korea.
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He J, Zhang X, Lian C, Wu J, Fang Y, Ye X. Exendin-4 prevented pancreatic beta cells from apoptosis in (Type I) diabetic mouse via keap1-Nrf2 signaling. Exp Biol Med (Maywood) 2019; 244:28-35. [PMID: 30638057 PMCID: PMC6362529 DOI: 10.1177/1535370218823549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 12/05/2018] [Indexed: 01/11/2023] Open
Abstract
IMPACT STATEMENT Nrf2 is an essential part of the defense mechanism of vertebrates and protects them from surrounding stress via participation in stimulated expression of detoxification as well as antioxidant enzymes. It also exerts a role in defending hosts from different stress in the environment, including reactive oxygen species. Our study investigates the role of exendin-4 on Nrf2 pathway as well as cell death in pancreatic β-cell and in non-obese diabetic mice. Result of study indicates exendin-4 mediates activation of Keap1-Nrf2-ARE pathway and may serve as a potential agent to treat type I diabetes mellitus. In our research, we observed excessive reactive oxygen species production, low level of cell death, and PKC phosphorylation on exendine-4 treatment. Nrf2 knockdown led to suppression of reactive oxygen species generation as well as increasing apoptosis. Moreover, siRNA-mediated Nrf2 down-regulation attenuated the suppressive effect of exendin-4 in pancreatic β-cell viability, via modulating apoptosis promoting- and counteracting-proteins, Bax, and Bcl-2.
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Affiliation(s)
- Jinshui He
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
| | - Xu Zhang
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
| | - Chaowei Lian
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
| | - Jinzhi Wu
- Department of endocrinology, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
| | - Yanling Fang
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
| | - Xiaoling Ye
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou 363000, China
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He J, Zhang X, Lian C, Wu J, Fang Y, Ye X. KEAP1/NRF2 axis regulates H 2O 2-induced apoptosis of pancreatic β-cells. Gene 2018; 691:8-17. [PMID: 30594636 DOI: 10.1016/j.gene.2018.11.100] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/28/2018] [Accepted: 11/30/2018] [Indexed: 01/06/2023]
Abstract
In human pancreatic β-cells, oxidative stress and cellular injures can be induced by H2O2 treatment. The KEAP1/NRF2 axis is a key antioxidant signaling pathway. The present study attempted to elucidate the mechanism by which the KEAP1/NRF2 axis mediates oxidative stress-induced death in pancreatic β-cells. Our data showed that H2O2 treatment obviously induced the apoptosis of β-cells. Further experiments demonstrated that KEAP1 expression was downregulated in H2O2-treated pancreatic β-cells and this change correlated with increase in the cellular abundance and nuclear translocation of NRF2. The restoration of KEAP1 expression in cells resulted in a recovery of cell proliferation and inhibition of apoptosis. Furthermore, we found that KEAP1 overexpression negatively regulated the abundance of NRF2, subsequently causing decreased antioxidant response element activation. This led to HO-1 protein downregulation in H2O2-treated human pancreatic β-cells, which was also observed in NRF2-silenced β-cells. Conversely, the silencing of KEAP1 led to NRF2 upregulation and inhibited ARE and HO-1 signaling in pancreatic β-cells. The increase in the abundance of NRF2 following treatment with H2O2 drastically elevated the production of BAX, FAS, FAS-L, CASP-3, and CASP-9, and this change was reversed by KEAP1 overexpression or NRF2 silencing. Taken together, H2O2 treatment activated KEAP1/NRF2 signaling to promote the production of pro-apoptotic factors and consequently led to the apoptosis of human pancreatic β-cells.
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Affiliation(s)
- Jinshui He
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China
| | - Xu Zhang
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China
| | - Chaowei Lian
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China
| | - Jinzhi Wu
- Department of Endocrinology, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China
| | - Yanling Fang
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China
| | - Xiaoling Ye
- Department of Pediatrics, Affiliated Hospital of Zhangzhou, Fujian Medical University, Zhangzhou, Fujian, China.
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IAPP in type II diabetes: Basic research on structure, molecular interactions, and disease mechanisms suggests potential intervention strategies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018. [DOI: 10.1016/j.bbamem.2018.02.020] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Abedini A, Derk J, Schmidt AM. The receptor for advanced glycation endproducts is a mediator of toxicity by IAPP and other proteotoxic aggregates: Establishing and exploiting common ground for novel amyloidosis therapies. Protein Sci 2018; 27:1166-1180. [PMID: 29664151 PMCID: PMC6032365 DOI: 10.1002/pro.3425] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/09/2018] [Accepted: 04/10/2018] [Indexed: 12/23/2022]
Abstract
Proteotoxicity plays a key role in many devastating human disorders, including Alzheimer's, Huntington's and Parkinson's diseases; type 2 diabetes; systemic amyloidosis; and cardiac dysfunction, to name a few. The cellular mechanisms of proteotoxicity in these disorders have been the focus of considerable research, but their role in prevalent and morbid disorders, such as diabetes, is less appreciated. There is a large body of literature on the impact of glucotoxicity and lipotoxicity on insulin-producing pancreatic β-cells, and there is increasing recognition that proteotoxicty plays a key role. Pancreatic islet amyloidosis by the hormone IAPP, the production of advanced glycation endproducts (AGE), and insulin misprocessing into cytotoxic aggregates are all sources of β-cell proteotoxicity in diabetes. AGE, produced by the reaction of reducing sugars with proteins and lipids are ligands for the receptor for AGE (RAGE), as are the toxic pre-fibrillar aggregates of IAPP produced during amyloid formation. The mechanisms of amyloid formation by IAPP in vivo or in vitro are not well understood, and the cellular mechanisms of IAPP-induced β-cell death are not fully defined. Here, we review recent findings that illuminate the factors and mechanisms involved in β-cell proteotoxicity in diabetes. Together, these new insights have far-reaching implications for the establishment of unifying mechanisms by which pathological amyloidoses imbue their injurious effects in vivo.
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Affiliation(s)
- Andisheh Abedini
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
| | - Julia Derk
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Department of MedicineNew York University Medical Center, 550 First Avenue, Smilow 906New YorkNew York10016
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Singh S, Bhowmick DC, Pany S, Joe M, Zaghlula N, Jeremic AM. Apoptosis signal regulating kinase-1 and NADPH oxidase mediate human amylin evoked redox stress and apoptosis in pancreatic beta-cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2018; 1860:1721-1733. [PMID: 29627323 DOI: 10.1016/j.bbamem.2018.03.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 03/22/2018] [Accepted: 03/24/2018] [Indexed: 01/20/2023]
Abstract
Misfolded toxic human islet amyloid polypeptide or amylin (hA) and plasma membrane-associated redox complex, NADPH oxidase (NOX), have been implicated in the islet β-cell demise associated with type-2 diabetes mellitus (T2DM). Studies show that hA accumulation is stressful to β-cells and that misfolding of human amylin evokes redox stress and activates mitogen activated protein (MAP) kinases, p38 MAPK and c-Jun N-terminal (JNK) kinase. However, the molecular link and causality between hA-evoked redox stress, NOX activity and MAP kinases signaling in pancreatic β-cells is incompletely understood. Here, we show that in the process of activating JNK, aggregation prone hA also activates an upstream apoptosis signal regulating kinase-1 (ASK1) with concomitant decrease in intracellular levels of reduced glutathione. Inhibition of ASK1 kinase activity, either by specific ASK1 inhibitor, NQDI1 or by thiol antioxidants reduces human amylin-evoked ASK1 and JNK activation and consequently human amylin toxicity in rat insulinoma Rin-m5F cells and human islets. β-cell specific overexpression of human amylin in mouse islets elicited ASK1 phosphorylation and activation in β-cells but not in other rodent's islet or exocrine cells. This ASK1 activation strongly correlated with islet amyloidosis and diabetes progression. Cytotoxic human amylin additionally stimulated pro-oxidative activity and expressions of plasma membrane bound NADPH oxidase (NOX) and its regulatory subunits. siRNA mediated NOX1 knockdown and selective NOX inhibitors, ML171 and apocynin, significantly reduced hA-induced mitochondrial stress in insulinoma beta-cells. However, NOX inhibitors were largely ineffective against hA-evoked redox stress and activation of cytotoxic ASK1/JNK signaling complex. Thus, our studies suggest that NOX1 and ASK1 autonomously mediate human amylin-evoked redox and mitochondrial stress in pancreatic β-cells.
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Affiliation(s)
- Sanghamitra Singh
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | | | - Satyabrata Pany
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Myungkuk Joe
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Noor Zaghlula
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
| | - Aleksandar M Jeremic
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.
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Chen C, Wu S, Lin X, Wu D, Fischbach S, Xiao X. ERK5 plays an essential role in gestational beta-cell proliferation. Cell Prolif 2017; 51:e12410. [PMID: 29159830 DOI: 10.1111/cpr.12410] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 10/24/2017] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVES Restoring a functional beta-cell mass is a fundamental goal in treating diabetes. A complex signalling pathway network coordinates the regulation of beta-cell proliferation, although a role for ERK5 in this network has not been reported. This question was addressed in this study. MATERIALS AND METHODS We studied the activation of extracellular-signal-regulated kinase 5 (ERK5) in pregnant mice, a well-known mouse model of increased beta-cell proliferation. A specific inhibitor of ERK5 activation, BIX02189, was intraperitoneally injected into the pregnant mice to suppress ERK5 signalling. Beta-cell proliferation was determined by quantification of Ki-67+ beta cells. Beta-cell apoptosis was determined by TUNEL assay. The extent of beta-cell proliferation was determined by beta-cell mass. The alteration of ERK5 activation and CyclinD1 levels in purified mouse islets was examined by Western blotting. RESULTS Extracellular-signal-regulated kinase 5 phosphorylation, which represents ERK5 activation, was significantly upregulated in islets from pregnant mice. Suppression of ERK5 activation by BIX02189 in pregnant mice significantly reduced beta-cell proliferation, without affecting beta-cell apoptosis, resulting in increases in random blood glucose levels and impairment of glucose response of the mice. ERK5 seemed to activate CyclinD1 to promote gestational beta-cell proliferation. CONCLUSIONS Extracellular-signal-regulated kinase 5 plays an essential role in the gestational augmentation of beta-cell proliferation. ERK5 may be a promising target for increasing beta-cell mass in diabetes patients.
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Affiliation(s)
- Congde Chen
- Department of Pediatric Surgery, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Suichun Wu
- Reproductive Medicine Centre, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiaokun Lin
- Department of Pediatric Surgery, the Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China
| | - Dazhou Wu
- Department of Pediatric Surgery, the First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Shane Fischbach
- Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, USA
| | - Xiangwei Xiao
- Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, USA
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27
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Zhou Y, Chung ACK, Fan R, Lee HM, Xu G, Tomlinson B, Chan JCN, Kong APS. Sirt3 Deficiency Increased the Vulnerability of Pancreatic Beta Cells to Oxidative Stress-Induced Dysfunction. Antioxid Redox Signal 2017; 27:962-976. [PMID: 28375738 DOI: 10.1089/ars.2016.6859] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
AIMS Hyperlipidemia-induced oxidative stress is considered to be one of the main pathogenic factors that contribute to pancreatic beta cell dysfunction in the development of type 2 diabetes (T2D). Sirtuin 3 (Sirt3) is abundantly expressed in the mitochondria as an NAD+-dependent deacetylase and regulates mitochondrial adaptive responses to oxidative stress. We examined the antioxidant defense mechanism of Sirt3 in pancreatic beta cells in the context of hyperlipidemia. RESULTS Chronic high-fat diet (HFD) feeding caused elevated oxidative stress accompanied by reduced Sirt3 expression in the pancreatic beta cells of wild-type mice. Primary pancreatic islets of Sirt3 knockout (KO) mice and murine pancreatic MIN6 cells with downregulated Sirt3 expression showed increased superoxide dismutase 2 (SOD2) acetylation and reduced glucose-stimulated insulin secretion and glucose-stimulated adenosine triphosphate (ATP) generation. Moreover, Sirt3 deficiency sensitized the pancreatic islets and MIN6 cells to palmitate- and H2O2-induced beta cell dysfunction linked with aggravated c-Jun N-terminal kinase phosphorylation and cleaved caspase-3 expression. These negative effects were reversed by antioxidant chemical treatment or restoration of Sirt3 in KO islets. Finally, overexpression of Sirt3 in MIN6 cells partially rescued palmitate-induced reactive oxygen species generation, pancreatic and duodenal homeobox-1 (Pdx-1) nucleo-cytoplasmic translocation, and beta cell dysfunction. INNOVATION We present that Sirt3 expression protected pancreatic beta cells from lipotoxicity by antagonizing oxidative stress-induced cell damage. CONCLUSION These results suggest that Sirt3 may be a target for amelioration of beta cell dysfunction due to obesity and T2D. Antioxid. Redox Signal. 27, 962-976.
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Affiliation(s)
- Yu Zhou
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,2 Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong
| | - Arthur C K Chung
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,4 Partner State Key Laboratory of Environmental and Biological Analysis and Department of Chemistry, The Hong Kong Baptist University , Hong Kong, Hong Kong
| | - Rongrong Fan
- 5 Department of Biosciences and Nutrition, Karolinska Institute , Stockholm, Sweden
| | - Heung Man Lee
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,2 Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong
| | - Gang Xu
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,6 School of Chinese Medicine, The Hong Kong Baptist University , Hong Kong, Hong Kong
| | - Brian Tomlinson
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong
| | - Juliana C N Chan
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,2 Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong
| | - Alice P S Kong
- 1 Department of Medicine and Therapeutics, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,2 Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong .,3 Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong , Prince of Wales Hospital, Hong Kong, Hong Kong
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28
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Templin AT, Samarasekera T, Meier DT, Hogan MF, Mellati M, Crow MT, Kitsis RN, Zraika S, Hull RL, Kahn SE. Apoptosis Repressor With Caspase Recruitment Domain Ameliorates Amyloid-Induced β-Cell Apoptosis and JNK Pathway Activation. Diabetes 2017; 66:2636-2645. [PMID: 28729244 PMCID: PMC5606321 DOI: 10.2337/db16-1352] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 07/13/2017] [Indexed: 12/28/2022]
Abstract
Islet amyloid is present in more than 90% of individuals with type 2 diabetes, where it contributes to β-cell apoptosis and insufficient insulin secretion. Apoptosis repressor with caspase recruitment domain (ARC) binds and inactivates components of the intrinsic and extrinsic apoptosis pathways and was recently found to be expressed in islet β-cells. Using a human islet amyloid polypeptide transgenic mouse model of islet amyloidosis, we show ARC knockdown increases amyloid-induced β-cell apoptosis and loss, while ARC overexpression decreases amyloid-induced apoptosis, thus preserving β-cells. These effects occurred in the absence of changes in islet amyloid deposition, indicating ARC acts downstream of amyloid formation. Because islet amyloid increases c-Jun N-terminal kinase (JNK) pathway activation, we investigated whether ARC affects JNK signaling in amyloid-forming islets. We found ARC knockdown enhances JNK pathway activation, whereas ARC overexpression reduces JNK, c-Jun phosphorylation, and c-Jun target gene expression (Jun and Tnf). Immunoprecipitation of ARC from mouse islet lysates showed ARC binds JNK, suggesting interaction between JNK and ARC decreases amyloid-induced JNK phosphorylation and downstream signaling. These data indicate that ARC overexpression diminishes amyloid-induced JNK pathway activation and apoptosis in the β-cell, a strategy that may reduce β-cell loss in type 2 diabetes.
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Affiliation(s)
- Andrew T Templin
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Tanya Samarasekera
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Daniel T Meier
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Meghan F Hogan
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Mahnaz Mellati
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Michael T Crow
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology and Wilf Family Cardiovascular Research Institute, Albert Einstein College of Medicine, Bronx, NY
| | - Sakeneh Zraika
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Rebecca L Hull
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
| | - Steven E Kahn
- VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, WA
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29
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The Physiological and Pathological Implications of the Formation of Hydrogels, with a Specific Focus on Amyloid Polypeptides. Biomolecules 2017; 7:biom7040070. [PMID: 28937634 PMCID: PMC5745453 DOI: 10.3390/biom7040070] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 08/30/2017] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
Hydrogels are water-swollen and viscoelastic three-dimensional cross-linked polymeric network originating from monomer polymerisation. Hydrogel-forming polypeptides are widely found in nature and, at a cellular and organismal level, they provide a wide range of functions for the organism making them. Amyloid structures, arising from polypeptide aggregation, can be damaging or beneficial to different types of organisms. Although the best-known amyloids are those associated with human pathologies, this underlying structure is commonly used by higher eukaryotes to maintain normal cellular activities, and also by microbial communities to promote their survival and growth. Amyloidogenesis occurs by nucleation-dependent polymerisation, which includes several species (monomers, nuclei, oligomers, and fibrils). Oligomers of pathological amyloids are considered the toxic species through cellular membrane perturbation, with the fibrils thought to represent a protective sink for toxic species. However, both functional and disease-associated amyloids use fibril cross-linking to form hydrogels. The properties of amyloid hydrogels can be exploited by organisms to fulfil specific physiological functions. Non-physiological hydrogelation by pathological amyloids may provide additional toxic mechanism(s), outside of membrane toxicity by oligomers, such as physical changes to the intracellular and extracellular environments, with wide-spread consequences for many structural and dynamic processes, and overall effects on cell survival.
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30
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Protective effects of a G. lucidum proteoglycan on INS-1 cells against IAPP-induced apoptosis via attenuating endoplasmic reticulum stress and modulating CHOP/JNK pathways. Int J Biol Macromol 2017; 106:893-900. [PMID: 28893685 DOI: 10.1016/j.ijbiomac.2017.08.089] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 08/03/2017] [Accepted: 08/14/2017] [Indexed: 01/09/2023]
Abstract
Fudan-Yueyang-G. lucidum (FYGL) is a water-soluble macromolecular proteoglycan extracted from Ganoderma lucidum which has been used for health promotion for a long time in China. The aim of this study was to investigate the protective effects of FYGL on INS-1 rat insulinoma beta cells against IAPP-induced cell apoptosis, as well as the underlying mechanisms. The results showed that apoptotic cells were significantly increased when incubated with islet amyloid polypeptide (IAPP). However, cytotoxicity of IAPP was significantly attenuated by co-incubation of the cells with FYGL. The results of RT-PCR showed that mRNA expression of caspase-3, caspase-12 and C/EBP homologous protein (CHOP) in IAPP-treated cells were inhibited by FYGL. Moreover, FYGL significantly prevented the IAPP-induced abnormal expression of inositol-requiring protein-1α (IRE1α), protein kinase RNA (PKR)-like ER kinase (PERK), activating transcription factor 6 (ATF6), as well as suppressed the activation of CHOP and c-Jun N-terminal kinase (JNK). Taken together, our results suggest that FYGL protects INS-1 pancreatic beta cells against IAPP-induced apoptosis through attenuating endoplasmic reticulum stress (ERS) and modulating CHOP/JNK pathways.
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31
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Zhang Y, Song W. Islet amyloid polypeptide: Another key molecule in Alzheimer's pathogenesis? Prog Neurobiol 2017; 153:100-120. [PMID: 28274676 DOI: 10.1016/j.pneurobio.2017.03.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 02/17/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
Recent epidemiological evidence reveals that patients suffering from type 2 diabetes mellitus (T2DM) often experience a significant decline in cognitive function, and approximately 70% of those cases eventually develop Alzheimer's disease (AD). Although several pathological processes are shared by AD and T2DM, the exact molecular mechanisms connecting these two diseases are poorly understood. Aggregation of human islet amyloid polypeptide (hIAPP), the pathological hallmark of T2DM, has also been detected in brain tissue and is associated with cognitive decline and AD development. In addition, hIAPP and amyloid β protein (Aβ) share many biophysical and physiological properties as well as exert similar cytotoxic mechanisms. Therefore, it is important to examine the possible role of hIAPP in the pathogenesis of AD. In this article, we introduce the basics on this amyloidogenic protein. More importantly, we discuss the potential mechanisms of hIAPP-induced AD development, which will be beneficial for proposing novel and feasible strategies to optimize AD prevention and/or treatment in diabetics.
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Affiliation(s)
- Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, 2255 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada.
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Dalmo J, Spetz J, Montelius M, Langen B, Arvidsson Y, Johansson H, Parris TZ, Helou K, Wängberg B, Nilsson O, Ljungberg M, Forssell-Aronsson E. Priming increases the anti-tumor effect and therapeutic window of 177Lu-octreotate in nude mice bearing human small intestine neuroendocrine tumor GOT1. EJNMMI Res 2017; 7:6. [PMID: 28097640 PMCID: PMC5241264 DOI: 10.1186/s13550-016-0247-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022] Open
Abstract
Background 177Lu-[DOTA0, Tyr3]-octreotate (177Lu-octreotate) is used for treatment of patients with somatostatin receptor (SSTR) expressing neuroendocrine tumors. However, complete tumor remission is rarely seen, and optimization of treatment protocols is needed. In vitro studies have shown that irradiation can up-regulate the expression of SSTR1, 2 and 5, and increase 177Lu-octreotate uptake. The aim of the present study was to examine the anti-tumor effect of a 177Lu-octreotate priming dose followed 24 h later by a second injection of 177Lu-octreotate compared to a single administration of 177Lu-octreotate, performed on the human small intestine neuroendocrine tumor cell line, GOT1, transplanted to nude mice. Results Priming resulted in a 1.9 times higher mean absorbed dose to the tumor tissue per administered activity, together with a reduced mean absorbed dose for kidneys. Priming gave the best overall anti-tumor effects. Magnetic resonance imaging showed no statistically significant difference in tumor response between treatment with and without priming. Gene expression analysis demonstrated effects on cell cycle regulation. Biological processes associated with apoptotic cell death were highly affected in the biodistribution and dosimetry study, via differential regulation of, e.g., APOE, BAX, CDKN1A, and GADD45A. Conclusions Priming had the best overall anti-tumor effects and also resulted in an increased therapeutic window. Results indicate that potential biomarkers for tumor regrowth may be found in the p53 or JNK signaling pathways. Priming administration is an interesting optimization strategy for 177Lu-octreotate therapy of neuroendocrine tumors, and further studies should be performed to determine the mechanisms responsible for the reported effects. Electronic supplementary material The online version of this article (doi:10.1186/s13550-016-0247-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Johanna Dalmo
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden.
| | - Johan Spetz
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Mikael Montelius
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Britta Langen
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Yvonne Arvidsson
- Department of Pathology, Institute of Biomedicine, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Henrik Johansson
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Toshima Z Parris
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Khalil Helou
- Department of Oncology, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Bo Wängberg
- Department of Surgery, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Ola Nilsson
- Department of Pathology, Institute of Biomedicine, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Maria Ljungberg
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
| | - Eva Forssell-Aronsson
- Department of Radiation Physics, Institute of Clinical Sciences, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, SE-413 45, Gothenburg, Sweden
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33
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Zhang X, St Clair JR, London E, Raleigh DP. Islet Amyloid Polypeptide Membrane Interactions: Effects of Membrane Composition. Biochemistry 2017; 56:376-390. [PMID: 28054763 DOI: 10.1021/acs.biochem.6b01016] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Amyloid formation by islet amyloid polypeptide (IAPP) contributes to β-cell dysfunction in type 2 diabetes. Perturbation of the β-cell membrane may contribute to IAPP-induced toxicity. We examine the effects of lipid composition, salt, and buffer on IAPP amyloid formation and on the ability of IAPP to induce leakage of model membranes. Even low levels of anionic lipids promote amyloid formation and membrane permeabilization. Increasing the percentage of the anionic lipids, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine (POPS) or 1,2-dioleoyl-sn-glycero-3-phospho(1'-rac-glycerol), enhances the rate of amyloid formation and increases the level of membrane permeabilization. The choice of zwitterionic lipid has no noticeable effect on membrane-catalyzed amyloid formation but in most cases affects leakage, which tends to decrease in the following order: 1,2-dioleoyl-sn-glycero-3-phosphocholine > 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine > sphingomyelin. Uncharged lipids that increase the level of membrane order weaken the ability of IAPP to induce leakage. Leakage is due predominately to pore formation rather than complete disruption of the vesicles under the conditions used in these studies. Cholesterol at or below physiological levels significantly reduces the rate of vesicle-catalyzed IAPP amyloid formation and decreases the susceptibility to IAPP-induced leakage. The effects of cholesterol on amyloid formation are masked by 25 mol % POPS. Overall, there is a strong inverse correlation between the time to form amyloid and the extent of vesicle leakage. NaCl reduces the rate of membrane-catalyzed amyloid formation by anionic vesicles, but accelerates amyloid formation in solution. The implications for IAPP membrane interactions are discussed, as is the possibility that the loss of phosphatidylserine asymmetry enhances IAPP amyloid formation and membrane damage in vivo via a positive feedback loop.
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Affiliation(s)
- Xiaoxue Zhang
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Johnna R St Clair
- Department of Biochemistry and Cell Biology, Stony Brook University , Stony Brook, New York 11794-5215, United States
| | - Erwin London
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Department of Biochemistry and Cell Biology, Stony Brook University , Stony Brook, New York 11794-5215, United States
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.,Graduate Program in Biochemistry and Structural Biology, Stony Brook University , Stony Brook, New York 11794-5215, United States
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Bhowmick DC, Singh S, Trikha S, Jeremic AM. The Molecular Physiopathogenesis of Islet Amyloidosis. Handb Exp Pharmacol 2017; 245:271-312. [PMID: 29043504 DOI: 10.1007/164_2017_62] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Human islet amyloid polypeptide or amylin (hA) is a 37-amino acid peptide hormone produced and co-secreted with insulin by pancreatic β-cells. Under physiological conditions, hA regulates a broad range of biological processes including insulin release and slowing of gastric emptying, thereby maintaining glucose homeostasis. However, under the pathological conditions associated with type 2 diabetes mellitus (T2DM), hA undergoes a conformational transition from soluble random coil monomers to alpha-helical oligomers and insoluble β-sheet amyloid fibrils or amyloid plaques. There is a positive correlation between hA oligomerization/aggregation, hA toxicity, and diabetes progression. Because the homeostatic balance between hA synthesis, release, and uptake is lost in diabetics and hA aggregation is a hallmark of T2DM, this chapter focuses on the biophysical and cell biology studies investigating molecular mechanisms of hA uptake, trafficking, and degradation in pancreatic cells and its relevance to h's toxicity. We will also discuss the regulatory role of endocytosis and proteolytic pathways in clearance of toxic hA species. Finally, we will discuss potential pharmacological approaches for specific targeting of hA trafficking pathways and toxicity in islet β-cells as potential new avenues toward treatments of T2DM patients.
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Affiliation(s)
| | - Sanghamitra Singh
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - Saurabh Trikha
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA
| | - Aleksandar M Jeremic
- Department of Biological Sciences, The George Washington University, Washington, DC, 20052, USA.
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Yuan T, Rafizadeh S, Azizi Z, Lupse B, Gorrepati KDD, Awal S, Oberholzer J, Maedler K, Ardestani A. Proproliferative and antiapoptotic action of exogenously introduced YAP in pancreatic β cells. JCI Insight 2016; 1:e86326. [PMID: 27812538 DOI: 10.1172/jci.insight.86326] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Loss of functional pancreatic β cells is a hallmark of both type 1 and 2 diabetes. Identifying the pathways that promote β cell proliferation and/or block β cell apoptosis is a potential strategy for diabetes therapy. The transcriptional coactivator Yes-associated protein (YAP), a major downstream effector of the Hippo signaling pathway, is a key regulator of organ size and tissue homeostasis by modulating cell proliferation and apoptosis. YAP is not expressed in mature primary human and mouse β cells. We aimed to identify whether reexpression of a constitutively active form of YAP promotes β cell proliferation/survival. Overexpression of YAP remarkably induced β cell proliferation in isolated human islets, while β cell function and functional identity genes were fully preserved. The transcription factor forkhead box M1 (FOXM1) was upregulated upon YAP overexpression and necessary for YAP-dependent β cell proliferation. YAP overexpression protected β cells from apoptosis triggered by multiple diabetic conditions. The small redox proteins thioredoxin-1 and thioredoxin-2 (Trx1/2) were upregulated by YAP; disruption of the Trx system revealed that Trx1/2 was required for the antiapoptotic action of YAP in insulin-producing β cells. Our data show the robust proproliferative and antiapoptotic function of YAP in pancreatic β cells. YAP reconstitution may represent a disease-modifying approach to restore a functional β cell mass in diabetes.
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Affiliation(s)
- Ting Yuan
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Sahar Rafizadeh
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Zahra Azizi
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Blaz Lupse
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | | | - Sushil Awal
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
| | - Jose Oberholzer
- Division of Transplantation, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Kathrin Maedler
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany.,German Center for Diabetes Research (DZD) project partner, University of Bremen, Bremen, Germany
| | - Amin Ardestani
- Centre for Biomolecular Interactions Bremen, University of Bremen, Bremen, Germany
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Bensellam M, Maxwell EL, Chan JY, Luzuriaga J, West PK, Jonas JC, Gunton JE, Laybutt DR. Hypoxia reduces ER-to-Golgi protein trafficking and increases cell death by inhibiting the adaptive unfolded protein response in mouse beta cells. Diabetologia 2016; 59:1492-1502. [PMID: 27039902 DOI: 10.1007/s00125-016-3947-y] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 03/16/2016] [Indexed: 12/13/2022]
Abstract
AIMS/HYPOTHESIS Hypoxia may contribute to beta cell failure in type 2 diabetes and islet transplantation. The adaptive unfolded protein response (UPR) is required for endoplasmic reticulum (ER) homeostasis. Here we investigated whether or not hypoxia regulates the UPR in beta cells and the role the adaptive UPR plays during hypoxic stress. METHODS Mouse islets and MIN6 cells were exposed to various oxygen (O2) tensions. DNA-damage inducible transcript 3 (DDIT3), hypoxia-inducible transcription factor (HIF)1α and HSPA5 were knocked down using small interfering (si)RNA; Hspa5 was also overexpressed. db/db mice were used. RESULTS Hypoxia-response genes were upregulated in vivo in the islets of diabetic, but not prediabetic, db/db mice. In isolated mouse islets and MIN6 cells, O2 deprivation (1-5% vs 20%; 4-24 h) markedly reduced the expression of adaptive UPR genes, including Hspa5, Hsp90b1, Fkbp11 and spliced Xbp1. Coatomer protein complex genes (Copa, Cope, Copg [also known as Copg1], Copz1 and Copz2) and ER-to-Golgi protein trafficking were also reduced, whereas apoptotic genes (Ddit3, Atf3 and Trb3 [also known as Trib3]), c-Jun N-terminal kinase (JNK) phosphorylation and cell death were increased. Inhibition of JNK, but not HIF1α, restored adaptive UPR gene expression and ER-to-Golgi protein trafficking while protecting against apoptotic genes and cell death following hypoxia. DDIT3 knockdown delayed the loss of the adaptive UPR and partially protected against hypoxia-induced cell death. The latter response was prevented by HSPA5 knockdown. Finally, Hspa5 overexpression significantly protected against hypoxia-induced cell death. CONCLUSIONS/INTERPRETATION Hypoxia inhibits the adaptive UPR in beta cells via JNK and DDIT3 activation, but independently of HIF1α. Downregulation of the adaptive UPR contributes to reduced ER-to-Golgi protein trafficking and increased beta cell death during hypoxic stress.
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Affiliation(s)
- Mohammed Bensellam
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Emma L Maxwell
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jeng Yie Chan
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jude Luzuriaga
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Phillip K West
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
| | - Jean-Christophe Jonas
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium
| | - Jenny E Gunton
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia
- Westmead Hospital, Sydney, NSW, Australia
- The Westmead Millennium Institute for Medical Research, The University of Sydney, Sydney, NSW, Australia
| | - D Ross Laybutt
- Garvan Institute of Medical Research, St Vincent's Hospital, UNSW Australia, 384 Victoria Street, Darlinghurst, Sydney, NSW, 2010, Australia.
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Gurlo T, Rivera JF, Butler AE, Cory M, Hoang J, Costes S, Butler PC. CHOP Contributes to, But Is Not the Only Mediator of, IAPP Induced β-Cell Apoptosis. Mol Endocrinol 2016; 30:446-54. [PMID: 26900721 DOI: 10.1210/me.2015-1255] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The islet in type 2 diabetes is characterized by β-cell loss, increased β-cell apoptosis, and islet amyloid derived from islet amyloid polypeptide (IAPP). When protein misfolding protective mechanisms are overcome, human IAPP (h-IAPP) forms membrane permeant toxic oligomers that induce β-cell dysfunction and apoptosis. In humans with type 2 diabetes (T2D) and mice transgenic for h-IAPP, endoplasmic reticulum (ER) stress has been inferred from nuclear translocation of CCAAT/enhancer-binding protein homologous protein (CHOP), an established mediator of ER stress. To establish whether h-IAPP toxicity is mediated by ER stress, we evaluated diabetes onset and β-cell mass in h-IAPP transgenic (h-TG) mice with and without deletion of CHOP in comparison with wild-type controls. Diabetes was delayed in h-TG CHOP(-/-) mice, with relatively preserved β-cell mass and decreased β-cell apoptosis. Deletion of CHOP attenuates dysfunction of the autophagy/lysosomal pathway in β-cells of h-TG mice, uncovering a role for CHOP in mediating h-IAPP-induced dysfunction of autophagy. As deletion of CHOP delayed but did not prevent h-IAPP-induced β-cell loss and diabetes, we examined CHOP-independent stress pathways. JNK, a target of the IRE-1pTRAF2 complex, and the Bcl-2 family proapoptotic mediator BIM, a target of ATF4, were comparably activated by h-IAPP expression in the presence and absence of CHOP. Therefore, although these studies affirm that CHOP is a mediator of h-IAPP-induced ER stress, it is not the only one. Therefore, suppression of CHOP alone is unlikely to be a durable therapeutic strategy to protect against h-IAPP toxicity because multiple stress pathways are activated.
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Affiliation(s)
- T Gurlo
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - J F Rivera
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - A E Butler
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - M Cory
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - J Hoang
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - S Costes
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
| | - Peter C Butler
- Larry L. Hillblom Islet Research Center, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095-7073
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Khodabandehloo H, Gorgani-Firuzjaee S, Panahi G, Meshkani R. Molecular and cellular mechanisms linking inflammation to insulin resistance and β-cell dysfunction. Transl Res 2016; 167:228-56. [PMID: 26408801 DOI: 10.1016/j.trsl.2015.08.011] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 08/29/2015] [Accepted: 08/31/2015] [Indexed: 12/13/2022]
Abstract
Obesity is a major public health problem worldwide, and it is associated with an increased risk of developing type 2 diabetes. It is now commonly accepted that chronic inflammation associated with obesity induces insulin resistance and β-cell dysfunction in diabetic patients. Obesity-associated inflammation is characterized by increased abundance of macrophages and enhanced production of inflammatory cytokines in adipose tissue. Adipose tissue macrophages are suggested to be the major source of local and systemic inflammatory mediators such as tumor necrosis factor α, interleukin (IL)-1β, and IL-6. These cytokines induce insulin resistance in insulin target tissues by activating the suppressors of cytokine signaling proteins, several kinases such as c-Jun N-terminal kinase, IκB kinase β, and protein kinase C, inducible nitric oxide synthase, extracellular signal-regulated kinase, and protein tyrosine phosphatases such as protein tyrosine phosphatase 1B. These activated factors impair the insulin signaling at the insulin receptor and the insulin receptor substrates levels. The same process most likely occurs in the pancreas as it contains a pool of tissue-resident macrophages. High concentrations of glucose or palmitate via the chemokine production promote further immune cell migration and infiltration into the islets. These events ultimately induce inflammatory responses leading to the apoptosis of the pancreatic β cells. In this review, the cellular and molecular players that participate in the regulation of obesity-induced inflammation are discussed, with particular attention being placed on the roles of the molecular players linking inflammation to insulin resistance and β-cell dysfunction.
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Affiliation(s)
- Hadi Khodabandehloo
- Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Sattar Gorgani-Firuzjaee
- Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Ghodratollah Panahi
- Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran
| | - Reza Meshkani
- Department of Biochemistry, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran.
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Caillon L, Hoffmann ARF, Botz A, Khemtemourian L. Molecular Structure, Membrane Interactions, and Toxicity of the Islet Amyloid Polypeptide in Type 2 Diabetes Mellitus. J Diabetes Res 2016; 2016:5639875. [PMID: 26636105 PMCID: PMC4655289 DOI: 10.1155/2016/5639875] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 03/03/2015] [Indexed: 12/04/2022] Open
Abstract
Human islet amyloid polypeptide (hIAPP) is the major component of the amyloid deposits found in the pancreatic islets of patients with type 2 diabetes mellitus (T2DM). Mature hIAPP, a 37-aa peptide, is natively unfolded in its monomeric state but forms islet amyloid in T2DM. In common with other misfolded and aggregated proteins, amyloid formation involves aggregation of monomers of hIAPP into oligomers, fibrils, and ultimately mature amyloid deposits. hIAPP is coproduced and stored with insulin by the pancreatic islet β-cells and is released in response to the stimuli that lead to insulin secretion. Accumulating evidence suggests that hIAPP amyloid deposits that accompany T2DM are not just an insignificant phenomenon derived from the disease progression but that hIAPP aggregation induces processes that impair the functionality and the viability of β-cells. In this review, we particularly focus on hIAPP structure, hIAPP aggregation, and hIAPP-membrane interactions. We will also discuss recent findings on the mechanism of hIAPP-membrane damage and on hIAPP-induced cell death. Finally, the development of successful antiamyloidogenic agents that prevent hIAPP fibril formation will be examined.
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Affiliation(s)
- Lucie Caillon
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Anais R. F. Hoffmann
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Alexandra Botz
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
| | - Lucie Khemtemourian
- Sorbonne Universités, UPMC Univ Paris 06, Laboratoire des Biomolécules, 4 Place Jussieu, 75005 Paris, France
- Département de Chimie, Ecole Normale Supérieure, PSL Research University, 24 Rue Lhomond, 75005 Paris, France
- CNRS, UMR 7203 Laboratoire des Biomolécules, 75005 Paris, France
- *Lucie Khemtemourian:
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40
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Pal M, Febbraio MA, Lancaster GI. The roles of c-Jun NH2-terminal kinases (JNKs) in obesity and insulin resistance. J Physiol 2015; 594:267-79. [PMID: 26608096 DOI: 10.1113/jp271457] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/21/2015] [Indexed: 12/15/2022] Open
Abstract
Obesity is currently at epidemic levels worldwide and is associated with a wide range of diseases such as type 2 diabetes, cardiovascular disease, fatty liver disease and certain forms of cancer. Obesity-induced chronic inflammation is central to the disrupted metabolic homeostasis which underlies many of these conditions. While research over the past decade has identified many of the cells and signalling molecules that contribute to obesity-induced inflammation, perhaps the best characterised are the stress-activated c-Jun NH2 -terminal kinases (JNKs). JNKs are activated in obesity in numerous metabolically important cells and tissues such as adipose tissue, macrophages, liver, skeletal muscle and regions of the brain and pituitary. Elegant in vivo mouse studies using Cre-LoxP-mediated recombination of the JNK1 and JNK2 genes have revealed the remarkably diverse roles that JNKs play in the development of obesity-induced inflammation, impaired glucose homeostasis and hepatic steatosis. While JNK activation in classical metabolically active tissues such as skeletal muscle and adipose tissue only appears to play a minor role on the induction of the above-mentioned pathologies, recent studies have clearly established the important roles JNK signalling fulfils in macrophages, the liver and cells of the anterior pituitary. Collectively, these studies place JNKs as important mediators of obesity and obesity-associated disruptions to metabolic homeostasis.
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Affiliation(s)
- Martin Pal
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia
| | - Mark A Febbraio
- Division of Diabetes and Metabolism, Garvan Institute of Medical Research, Darlinghurst, Sydney, Australia.,Cellular & Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
| | - Graeme I Lancaster
- Cellular & Molecular Metabolism Laboratory, Baker IDI Heart and Diabetes Institute, Melbourne, Australia
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41
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Akter R, Cao P, Noor H, Ridgway Z, Tu LH, Wang H, Wong AG, Zhang X, Abedini A, Schmidt AM, Raleigh DP. Islet Amyloid Polypeptide: Structure, Function, and Pathophysiology. J Diabetes Res 2015; 2016:2798269. [PMID: 26649319 PMCID: PMC4662979 DOI: 10.1155/2016/2798269] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/24/2015] [Indexed: 01/29/2023] Open
Abstract
The hormone islet amyloid polypeptide (IAPP, or amylin) plays a role in glucose homeostasis but aggregates to form islet amyloid in type-2 diabetes. Islet amyloid formation contributes to β-cell dysfunction and death in the disease and to the failure of islet transplants. Recent work suggests a role for IAPP aggregation in cardiovascular complications of type-2 diabetes and hints at a possible role in type-1 diabetes. The mechanisms of IAPP amyloid formation in vivo or in vitro are not understood and the mechanisms of IAPP induced β-cell death are not fully defined. Activation of the inflammasome, defects in autophagy, ER stress, generation of reactive oxygen species, membrane disruption, and receptor mediated mechanisms have all been proposed to play a role. Open questions in the field include the relative importance of the various mechanisms of β-cell death, the relevance of reductionist biophysical studies to the situation in vivo, the molecular mechanism of amyloid formation in vitro and in vivo, the factors which trigger amyloid formation in type-2 diabetes, the potential role of IAPP in type-1 diabetes, the development of clinically relevant inhibitors of islet amyloidosis toxicity, and the design of soluble, bioactive variants of IAPP for use as adjuncts to insulin therapy.
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Affiliation(s)
- Rehana Akter
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Harris Noor
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Hui Wang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Amy G. Wong
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Xiaoxue Zhang
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
| | - Andisheh Abedini
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Ann Marie Schmidt
- Diabetes Research Program, NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Daniel P. Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794-3400, USA
- Research Department of Structural and Molecule Biology, University College London, Gower Street, London WC1E 6BT, UK
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42
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Meier DT, Entrup L, Templin AT, Hogan MF, Samarasekera T, Zraika S, Boyko EJ, Kahn SE. Determination of Optimal Sample Size for Quantification of β-Cell Area, Amyloid Area and β-Cell Apoptosis in Isolated Islets. J Histochem Cytochem 2015. [PMID: 26216141 DOI: 10.1369/0022155415585995] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Culture of isolated rodent islets is widely used in diabetes research to assess different endpoints, including outcomes requiring histochemical staining. As islet yields during isolation are limited, we determined the number of islets required to obtain reliable data by histology. We found that mean values for insulin-positive β-cell area/islet area, thioflavin S-positive amyloid area/islet area and β-cell apoptosis do not vary markedly when more than 30 islets are examined. Measurement variability declines as more islets are quantified, so that the variability of the coefficient of variation (CV) in human islet amyloid polypeptide (hIAPP) transgenic islets for β-cell area/islet area, amyloid area/islet area and β-cell apoptosis are 13.20% ± 1.52%, 10.03% ± 1.76% and 6.78% ± 1.53%, respectively (non-transgenic: 7.65% ± 1.17% β-cell area/islet area and 8.93% ± 1.56% β-cell apoptosis). Increasing the number of islets beyond 30 had marginal effects on the CV. Using 30 islets, 6 hIAPP-transgenic preparations are required to detect treatment effects of 14% for β-cell area/islet area, 30% for amyloid area/islet area and 23% for β-cell apoptosis (non-transgenic: 9% for β-cell area/islet area and 45% for β-cell apoptosis). This information will be of value in the design of studies using isolated islets to examine β cells and islet amyloid.
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Affiliation(s)
- Daniel T Meier
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Leon Entrup
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Andrew T Templin
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Meghan F Hogan
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Thanya Samarasekera
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
| | - Edward J Boyko
- Seattle Epidemiologic Research and Information Center, VA Puget Sound Health Care System and Division of General Internal Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (EJB)
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, VA Puget Sound Health Care System and University of Washington, Seattle, Washington (DTM, LE, ATT, MFH, TS, SZ, SEK)
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43
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Potter KJ, Werner I, Denroche HC, Montane J, Plesner A, Chen Y, Lei D, Soukhatcheva G, Warnock GL, Oberholzer J, Fraser PE, Verchere CB. Amyloid formation in human islets is enhanced by heparin and inhibited by heparinase. Am J Transplant 2015; 15:1519-30. [PMID: 25833002 DOI: 10.1111/ajt.13134] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 11/16/2014] [Accepted: 11/16/2014] [Indexed: 01/25/2023]
Abstract
Islet transplantation is a promising therapy for patients with diabetes, but its long-term success is limited by many factors, including the formation of islet amyloid deposits. Heparin is employed in clinical islet transplantation to reduce clotting but also promotes fibrillization of amyloidogenic proteins. We hypothesized that heparin treatment of islets during pre-transplant culture may enhance amyloid formation leading to beta cell loss and graft dysfunction. Heparin promoted the fibrillization of human islet amyloid polypeptide (IAPP) and enhanced its toxicity to INS-1 beta cells. Heparin increased amyloid deposition in cultured human islets, but surprisingly decreased islet cell apoptosis. Treatment of human islets with heparin prior to transplantation increased the likelihood of graft failure. Removal of islet heparan sulfate glycosaminoglycans, which localize with islet amyloid deposits in type 2 diabetes, by heparinase treatment decreased amyloid deposition and protected against islet cell death. These findings raise the possibility that pretransplant treatment of human islets with heparin could potentiate IAPP aggregation and amyloid formation and may be detrimental to subsequent graft function.
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Affiliation(s)
- K J Potter
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - I Werner
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - H C Denroche
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - J Montane
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A Plesner
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Y Chen
- Department of Medical Biophysics, Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, ON, Canada
| | - D Lei
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - G Soukhatcheva
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - G L Warnock
- Surgery, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - J Oberholzer
- Surgery, and Bioengineering, University of Illinois, Chicago, IL
| | - P E Fraser
- Department of Medical Biophysics, Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, ON, Canada
| | - C B Verchere
- Departments of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.,Surgery, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
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44
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Ergin V, Bali EB, Hariry RE, Karasu C. Natural products and the aging process. Horm Mol Biol Clin Investig 2015; 16:55-64. [PMID: 25436747 DOI: 10.1515/hmbci-2013-0031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 07/26/2013] [Indexed: 11/15/2022]
Abstract
Abstract Literature surveys show that the most of the research that have been conducted on the effect of herbal remedies on many tissue pathologies, including metabolic disturbances, cardiovascular decline, neurodegeneration, cataract, diabetic retinopathy and skin inflammation, all lead to an accelerated aging process. The increased carbonylation of proteins (carbonyl stress) disturbing their function has been indicated as an underlying mechanism of cellular senescence and age-related diseases. Because it is also linked to the carbonyl stress, aging chronic disease and inflammation plays an important role in understanding the clinical implications of cellular stress response and relevant markers. Greater knowledge of the molecular and cellular mechanisms involved in several pathologies associated with aging would provide a better understanding to help us to develop suitable strategies, use specific targets to mitigate the effect of human aging, prevent particularly chronic degenerative diseases and improve quality of life. However, research is lacking on the herbal compounds affecting cellular aging signaling as well as studies regarding the action mechanism(s) of natural products in prevention of the age-related disease. This review provides leads for identifying new medicinal agents or potential phytochemical drugs from plant sources for the prevention or delaying cellular aging processes and the treatment of some disorders related with accelerated body aging.
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45
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Tomasello MF, Sinopoli A, Pappalardo G. On the Environmental Factors Affecting the Structural and Cytotoxic Properties of IAPP Peptides. J Diabetes Res 2015; 2015:918573. [PMID: 26582441 PMCID: PMC4637107 DOI: 10.1155/2015/918573] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 02/05/2015] [Indexed: 12/18/2022] Open
Abstract
Pancreatic islets in type 2 diabetes mellitus (T2DM) patients are characterized by reduced β-cells mass and diffuse extracellular amyloidosis. Amyloid deposition involves the islet amyloid polypeptide (IAPP), a neuropancreatic hormone cosecreted with insulin by β-cells. IAPP is physiologically involved in glucose homeostasis, but it may turn toxic to β-cells owing to its tendency to misfold giving rise to oligomers and fibrils. The process by which the unfolded IAPP starts to self-assemble and the overall factors promoting this conversion are poorly understood. Other open questions are related to the nature of the IAPP toxic species and how exactly β-cells die. Over the last decades, there has been growing consensus about the notion that early molecular assemblies, notably small hIAPP oligomers, are the culprit of β-cells decline. Numerous environmental factors might affect the conformational, aggregation, and cytotoxic properties of IAPP. Herein we review recent progress in the field, focusing on the influences that membranes, pH, and metal ions may have on the conformational conversion and cytotoxicity of full-length IAPP as well as peptide fragments thereof. Current theories proposed for the mechanisms of toxicity will be also summarized together with an outline of the underlying molecular links between IAPP and amyloid beta (Aβ) misfolding.
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Affiliation(s)
| | - Alessandro Sinopoli
- International PhD Program in Translational Biomedicine, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Giuseppe Pappalardo
- CNR Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
- *Giuseppe Pappalardo:
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46
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Alejandro EU, Gregg B, Blandino-Rosano M, Cras-Méneur C, Bernal-Mizrachi E. Natural history of β-cell adaptation and failure in type 2 diabetes. Mol Aspects Med 2014; 42:19-41. [PMID: 25542976 DOI: 10.1016/j.mam.2014.12.002] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/04/2014] [Accepted: 12/05/2014] [Indexed: 02/07/2023]
Abstract
Type 2 diabetes mellitus (T2D) is a complex disease characterized by β-cell failure in the setting of insulin resistance. The current evidence suggests that genetic predisposition, and environmental factors can impair the capacity of the β-cells to respond to insulin resistance and ultimately lead to their failure. However, genetic studies have demonstrated that known variants account for less than 10% of the overall estimated T2D risk, suggesting that additional unidentified factors contribute to susceptibility of this disease. In this review, we will discuss the different stages that contribute to the development of β-cell failure in T2D. We divide the natural history of this process in three major stages: susceptibility, β-cell adaptation and β-cell failure, and provide an overview of the molecular mechanisms involved. Further research into mechanisms will reveal key modulators of β-cell failure and thus identify possible novel therapeutic targets and potential interventions to protect against β-cell failure.
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Affiliation(s)
- Emilyn U Alejandro
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Brigid Gregg
- Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA
| | - Manuel Blandino-Rosano
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Corentin Cras-Méneur
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, Brehm Center for Diabetes Research, University of Michigan, Ann Arbor, MI, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI, USA.
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47
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Fernández MS. Human IAPP amyloidogenic properties and pancreatic β-cell death. Cell Calcium 2014; 56:416-27. [PMID: 25224501 DOI: 10.1016/j.ceca.2014.08.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 08/09/2014] [Accepted: 08/20/2014] [Indexed: 02/07/2023]
Abstract
A hallmark of type 2 diabetes mellitus (T2DM) is the presence of extracellular amyloid deposits in the islets of Langerhans. These deposits are formed by the human islet amyloid polypeptide, hIAPP (or amylin), which is a hormone costored and cosecreted with insulin. Under normal conditions, the hormone remains in solution but, in the pancreas of T2DM individuals, it undergoes misfolding giving rise to oligomers and cross-β amyloid fibrils. Accumulating evidence suggests that the amyloid deposits that accompany type 2 diabetes mellitus are not just a trivial epiphenomenon derived from the disease progression. Rather, hIAPP aggregation induces processes that impair the functionality and viability of β-cells and may lead to apoptosis. The present review article aims to summarize a few aspects of the current knowledge of this amyloidogenic polypeptide. In the first place, the physicochemical properties which condition its propensity to misfold and form aggregates. Secondly, how these properties confer hIAPP the capacity to interfere with some signaling of the pancreatic β-cell, interact with membranes, form channels or affect natural ion channels, including calcium channels. Finally, how misfolded hIAPP cytotoxicity results in apoptosis. A number of pathophysiological changes of the T2DM islet can be related to the amyloidogenic properties of hIAPP. However, in a certain way, the in vivo aggregation of the polypeptide also reflects a failure of chaperones and, in general, of cellular proteostasis, supporting the view that T2DM may also be considered as a conformational disorder.
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Affiliation(s)
- Marta S Fernández
- Department of Biochemistry, Centro de Investigación y de Estudios Avanzados del I.P.N. (CINVESTAV), Ave, Politécnico 2508, PO Box 14-740, 07000 México D.F., Mexico.
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48
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Tomasello MF, Sinopoli A, Attanasio F, Giuffrida ML, Campagna T, Milardi D, Pappalardo G. Molecular and cytotoxic properties of hIAPP17-29 and rIAPP17-29 fragments: a comparative study with the respective full-length parent polypeptides. Eur J Med Chem 2014; 81:442-55. [PMID: 24859763 DOI: 10.1016/j.ejmech.2014.05.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 04/11/2014] [Accepted: 05/11/2014] [Indexed: 12/20/2022]
Abstract
The human islet polypeptide (hIAPP) or amylin is a 37-residue peptide hormone secreted by β-cells of the islet of Langerhans in the pancreas. Unlike the rat variant of IAPP (rIAPP), human amylin is highly amyloidogenic and is found as amyloid deposits in nearly 95% of patients afflicted with type 2 diabetes mellitus (T2DM). Human and rat IAPP have nearly identical primary sequence differing at only six positions which are encompassed within the 17-29 aminoacid region. Using Circular Dichroism (CD), Dynamic Light Scattering (DLS) and ThT-fluorescence (Th-T), we examined the aggregation properties of both full-length hIAPP1-37 and the related peptide fragment hIAPP17-29. For the sake of comparison, similar experiments were carried out on the respective rat variants rIAPP1-37 and rIAPP17-29. These studies were conducted at physiological pH in buffered solution not containing fluorinated co-solvents as well as in the presence of model membranes (LUV). In addition, the cytotoxic activity of the investigated peptides was determined toward different pancreatic β-cell lines. All the peptide studied in this work resulted cytotoxic despite β-sheet structure being observed, in vitro, for the hIAPP1-37 only. This suggests that β-sheet conformational transition that generally precedes the fibril formation, is not a prerequisite for toxicity towards β-cells. Interestingly, confocal microscopy indicated that the IAPP peptides can enter the cell and might exert their toxic action at an intracellular level.
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Affiliation(s)
| | - Alessandro Sinopoli
- International PhD Program in Translational Biomedicine, University of Catania, V.le A. Doria 6, 95125 Catania, Italy
| | - Francesco Attanasio
- CNR-Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
| | - Maria Laura Giuffrida
- CNR-Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
| | - Tiziana Campagna
- CNR-Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
| | - Danilo Milardi
- CNR-Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy
| | - Giuseppe Pappalardo
- CNR-Institute of Biostructures and Bioimaging, Via P. Gaifami 18, 95126 Catania, Italy.
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Abstract
Amyloid formation is a hallmark of protein misfolding diseases (e.g. Type II diabetes mellitus). The energetically unfavourable nucleation step of amyloidogenesis can be accelerated by seeding, during which pre-formed aggregates act as templates for monomer recruitment. Hydrophobic-hydrophilic interfaces [e.g. AWI (air-water interface)] can also catalyse amyloidogenesis due to the surfactant properties of amyloidogenic polypeptides. Using thioflavin T fluorescence and electron microscopy, we demonstrate that the outcome of seeding on human islet amyloid polypeptide amyloidogenesis is dependent upon whether the AWI is present or absent and is dictated by seed type. Seeding significantly inhibits (with AWI) or promotes (without AWI) plateau height compared with seedless controls; with short fibrils being more efficient seeds than their longer counterparts. Moreover, promotion of nucleation by increasing monomer concentrations can only be observed in the absence of an AWI. Using biophysical modelling, we suggest that a possible explanation for our results may reside in lateral interactions between seeds and monomers determining the fibril mass formed in seeded reactions at steady-state. Our results suggest that in vivo hydrophobic-hydrophilic interfaces (e.g. the presence of membranes and their turnover rate) may dictate the outcome of seeding during amyloidogenesis and that factors affecting the size of the pre-aggregate may be important.
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50
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Ergin V, Hariry RE, Karasu C. Carbonyl stress in aging process: role of vitamins and phytochemicals as redox regulators. Aging Dis 2013; 4:276-94. [PMID: 24124633 DOI: 10.14336/ad.2013.0400276] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 08/01/2013] [Accepted: 08/02/2013] [Indexed: 12/15/2022] Open
Abstract
There is a growing scientific agreement that the cellular redox regulators such as antioxidants, particularly the natural polyphenolic forms, may help lower the incidence of some pathologies, including metabolic diseases like diabetes and diabesity, cardiovascular and neurodegenerative abnormalities, and certain cancers or even have anti-aging properties. The recent researches indicate that the degree of metabolic modulation and adaptation response of cells to reductants as well as oxidants establish their survival and homeostasis, which is linked with very critical balance in imbalances in cellular redox capacity and signaling, and that might be an answer the questions why some antioxidants or phytochemicals potentially could do more harm than good, or why some proteins lose their function by increase interactions with glyco- and lipo-oxidation mediates in the cells (carbonyl stress). Nonetheless, pursue of healthy aging has led the use of antioxidants as a means to disrupt age-associated physiological dysfunctions, dysregulated metabolic processes or prevention of many age-related diseases. Although it is still early to define their exact clinical benefits for treating age-related disease, a diet rich in polyphenolic or other forms of antioxidants does seem to offer hope in delaying the onset of age-related disorders. It is now clear that any deficiency in antioxidant vitamins, inadequate enzymatic antioxidant defenses can distinctive for many age-related disease, and protein carbonylation can used as an indicator of oxidative stress associated diseases and aging status. This review examines antioxidant compounds and plant polyphenols as redox regulators in health, disease and aging processes with hope that a better understanding of the many mechanisms involved with these distinct compounds, which may lead to better health and novel treatment approaches for age-related diseases.
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Affiliation(s)
- Volkan Ergin
- Cellular Stress Response and Signal Transduction Research Laboratory, Department of Medical Pharmacology, Faculty of Medicine, Gazi University, Ankara, Turkey
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