1
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Tieu S, Charchoglyan A, Paulsen L, Wagter-Lesperance LC, Shandilya UK, Bridle BW, Mallard BA, Karrow NA. N-Acetylcysteine and Its Immunomodulatory Properties in Humans and Domesticated Animals. Antioxidants (Basel) 2023; 12:1867. [PMID: 37891946 PMCID: PMC10604897 DOI: 10.3390/antiox12101867] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 10/10/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
N-acetylcysteine (NAC), an acetylated derivative of the amino acid L-cysteine, has been widely used as a mucolytic agent and antidote for acetaminophen overdose since the 1960s and the 1980s, respectively. NAC possesses antioxidant, cytoprotective, anti-inflammatory, antimicrobial, and mucolytic properties, making it a promising therapeutic agent for a wide range of diseases in both humans and domesticated animals. Oxidative stress and inflammation play a major role in the onset and progression of all these diseases. NAC's primary role is to replenish glutathione (GSH) stores, the master antioxidant in all tissues; however, it can also reduce levels of pro-inflammatory tumor necrosis factor-alpha (TNF-∝) and interleukins (IL-6 and IL-1β), inhibit the formation of microbial biofilms and destroy biofilms, and break down disulfide bonds between mucin molecules. Many experimental studies have been conducted on the use of NAC to address a wide range of pathological conditions; however, its effectiveness in clinical trials remains limited and studies often have conflicting results. The purpose of this review is to provide a concise overview of promising NAC usages for the treatment of different human and domestic animal disorders.
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Affiliation(s)
- Sophie Tieu
- Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada; (S.T.); (U.K.S.)
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada; (L.P.); (L.C.W.-L.); (B.W.B.); (B.A.M.)
| | - Armen Charchoglyan
- ImmunoCeutica Inc., Cambridge, ON N1T 1N6, Canada
- Advanced Analysis Centre, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - Lauryn Paulsen
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada; (L.P.); (L.C.W.-L.); (B.W.B.); (B.A.M.)
| | - Lauri C. Wagter-Lesperance
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada; (L.P.); (L.C.W.-L.); (B.W.B.); (B.A.M.)
- ImmunoCeutica Inc., Cambridge, ON N1T 1N6, Canada
| | - Umesh K. Shandilya
- Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada; (S.T.); (U.K.S.)
| | - Byram W. Bridle
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada; (L.P.); (L.C.W.-L.); (B.W.B.); (B.A.M.)
- ImmunoCeutica Inc., Cambridge, ON N1T 1N6, Canada
| | - Bonnie A. Mallard
- Department of Pathobiology, University of Guelph, Guelph, ON N1G 2W1, Canada; (L.P.); (L.C.W.-L.); (B.W.B.); (B.A.M.)
- ImmunoCeutica Inc., Cambridge, ON N1T 1N6, Canada
| | - Niel A. Karrow
- Department of Animal Biosciences, University of Guelph, Guelph, ON N1G 2W1, Canada; (S.T.); (U.K.S.)
- ImmunoCeutica Inc., Cambridge, ON N1T 1N6, Canada
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2
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Roham PH, Save SN, Sharma S. Human islet amyloid polypeptide: A therapeutic target for the management of type 2 diabetes mellitus. J Pharm Anal 2022; 12:556-569. [PMID: 36105173 PMCID: PMC9463490 DOI: 10.1016/j.jpha.2022.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/21/2022] [Accepted: 04/01/2022] [Indexed: 12/22/2022] Open
Abstract
Type 2 diabetes mellitus (T2DM) and other metabolic disorders are often silent and go unnoticed in patients because of the lack of suitable prognostic and diagnostic markers. The current therapeutic regimens available for managing T2DM do not reverse diabetes; instead, they delay the progression of diabetes. Their efficacy (in principle) may be significantly improved if implemented at earlier stages. The misfolding and aggregation of human islet amyloid polypeptide (hIAPP) or amylin has been associated with a gradual decrease in pancreatic β-cell function and mass in patients with T2DM. Hence, hIAPP has been recognized as a therapeutic target for managing T2DM. This review summarizes hIAPP's role in mediating dysfunction and apoptosis in pancreatic β-cells via induction of endoplasmic reticulum stress, oxidative stress, mitochondrial dysfunction, inflammatory cytokine secretion, autophagy blockade, etc. Furthermore, it explores the possibility of using intermediates of the hIAPP aggregation pathway as potential drug targets for T2DM management. Finally, the effects of common antidiabetic molecules and repurposed drugs; other hIAPP mimetics and peptides; small organic molecules and natural compounds; nanoparticles, nanobodies, and quantum dots; metals and metal complexes; and chaperones that have demonstrated potential to inhibit and/or reverse hIAPP aggregation and can, therefore, be further developed for managing T2DM have been discussed. Misfolded species of hIAPP form toxic oligomers in pancreatic β-cells. hIAPP amyloids has been detected in the pancreas of about 90% subjects with T2DM. Inhibitors of hIAPP aggregation can help manage T2DM.
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3
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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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4
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Babych M, Nguyen PT, Côté-Cyr M, Kihal N, Quittot N, Golizeh M, Sleno L, Bourgault S. Site-Specific Alkylation of the Islet Amyloid Polypeptide Accelerates Self-Assembly and Potentiates Perturbation of Lipid Membranes. Biochemistry 2021; 60:2285-2299. [PMID: 34264642 DOI: 10.1021/acs.biochem.1c00308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The accumulation of insoluble amyloids in the pancreatic islets is a pathological hallmark of type II diabetes and correlates closely with the loss of β-cell mass. The predominant component of these amyloid deposits is the islet amyloid polypeptide (IAPP). The factors contributing to the conversion of IAPP from a monomeric bioactive peptide hormone into insoluble amyloid fibrils remain partially elusive. In this study, we investigated the effect of the oxidative non-enzymatic post-translational modification induced by the reactive metabolite 4-hydroxynonenal (HNE) on IAPP aggregation and cytotoxicity. Incubation of IAPP with exogenous HNE accelerated its self-assembly into β-sheet fibrils and led to the formation of a Michael adduct on the His-18 side chain. To model this covalent modification, the imidazole N(π) position of histidine was alkylated using a close analogue of HNE, the octyl chain. IAPP lipidated at His-18 showed a hastened random coil-to-β-sheet conformational conversion into fibrillar assemblies with a distinct morphology, a low level of binding to thioflavin T, and a high surface hydrophobicity. Introducing an octyl chain on His-18 enhanced the ability of the peptide to perturb synthetic lipid vesicles, to permeabilize the plasma membrane, and to induce the death of pancreatic β-cells. Alkylated IAPP triggered the self-assembly of unmodified IAPP by prompting primary nucleation and increased its capacity to perturb the plasma membrane, indicating that only a small proportion of the modified peptide is necessary to shift the balance toward the formation of proteotoxic species. This study underlines the importance of studying IAPP post-translational modifications induced by oxidative metabolites in the context of pancreatic amyloids.
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Affiliation(s)
- Margaryta Babych
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Phuong Trang Nguyen
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Mélanie Côté-Cyr
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Nadjib Kihal
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Noé Quittot
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
| | - Makan Golizeh
- Department of Mathematical and Physical Sciences, Concordia University of Edmonton, Edmonton, AB T5B 4E4, Canada
| | - Lekha Sleno
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada
| | - Steve Bourgault
- Department of Chemistry, Université du Québec à Montréal, C.P. 8888, Succursale Centre-Ville, Montreal H3C 3P8, Canada.,Quebec Network for Research on Protein Function, Engineering and Applications, PROTEO, http://proteo.ca/en/
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5
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Pedre B, Barayeu U, Ezeriņa D, Dick TP. The mechanism of action of N-acetylcysteine (NAC): The emerging role of H 2S and sulfane sulfur species. Pharmacol Ther 2021; 228:107916. [PMID: 34171332 DOI: 10.1016/j.pharmthera.2021.107916] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 12/19/2022]
Abstract
Initially adopted as a mucolytic about 60 years ago, the cysteine prodrug N-acetylcysteine (NAC) is the standard of care to treat paracetamol intoxication, and is included on the World Health Organization's list of essential medicines. Additionally, NAC increasingly became the epitome of an "antioxidant". Arguably, it is the most widely used "antioxidant" in experimental cell and animal biology, as well as clinical studies. Most investigators use and test NAC with the idea that it prevents or attenuates oxidative stress. Conventionally, it is assumed that NAC acts as (i) a reductant of disulfide bonds, (ii) a scavenger of reactive oxygen species and/or (iii) a precursor for glutathione biosynthesis. While these mechanisms may apply under specific circumstances, they cannot be generalized to explain the effects of NAC in a majority of settings and situations. In most cases the mechanism of action has remained unclear and untested. In this review, we discuss the validity of conventional assumptions and the scope of a newly discovered mechanism of action, namely the conversion of NAC into hydrogen sulfide and sulfane sulfur species. The antioxidative and cytoprotective activities of per- and polysulfides may explain many of the effects that have previously been ascribed to NAC or NAC-derived glutathione.
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Affiliation(s)
- Brandán Pedre
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Uladzimir Barayeu
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Daria Ezeriņa
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, DKFZ-ZMBH Alliance, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany; Faculty of Biosciences, Heidelberg University, 69120 Heidelberg, Germany.
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6
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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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7
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Tam NW, Chung D, Baldwin SJ, Simmons JR, Xu L, Rainey JK, Dellaire G, Frampton JP. Material properties of disulfide-crosslinked hyaluronic acid hydrogels influence prostate cancer cell growth and metabolism. J Mater Chem B 2021; 8:9718-9733. [PMID: 33015692 DOI: 10.1039/d0tb01570a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cells reside in vivo within three dimensional environments in which they interact with extracellular matrices (ECMs) that play an integral role in maintaining tissue homeostasis and preventing tumour growth. Thus, tissue culture approaches that more faithfully reproduce these interactions with the ECM are needed to study cancer development and progression. Many materials exist for modeling tissue environments, and the effects of differing mechanical, physical, and biochemical properties of such materials on cell behaviour are often intricately coupled and difficult to tease apart. Here, an optimized protocol was developed to generate low reaction volume disulfide-crosslinked hyaluronic acid (HA) hydrogels for use in cell culture applications to relate the properties of ECM materials to cell signalling and behaviour. Mechanically, HA hydrogels are comparable to other soft hydrogel materials such as Matrigel and agarose or to tissues lacking type I collagen and other fibrillar ECM components. The diffusion of soluble materials in these hydrogels is affected by unique mass transfer properties. Specifically, HA hydrogel concentration affects the diffusion of anionic particles above 500 kDa, whereas diffusion of smaller particles appears unimpeded by HA content, likely reflecting hydrogel pore size. The HA hydrogels have a strong exclusion effect that limits the movement of proteins into and out of the material once fully formed. Such mass transfer properties have interesting implications for cell culture, as they ultimately affect access to nutrients and the distribution of signalling molecules, affecting nutrient sensing and metabolic activity. The use of disulfide-crosslinked HA hydrogels for the culture of the model prostate cancer cell lines PC3 and LNCaP reveals correlations of protein activation linked to metabolic flux, which parallel and can thus potentially provide insights into cell survival mechanisms in response to starvation that occurs in cancer cell microenvironments.
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Affiliation(s)
- Nicky W Tam
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada.
| | - Dudley Chung
- Department of Pathology, Dalhousie University, Halifax, NS, Canada
| | - Samuel J Baldwin
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada.
| | - Jeffrey R Simmons
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Lingling Xu
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada
| | - Jan K Rainey
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada. and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada and Department of Chemistry, Dalhousie University, Halifax, NS, Canada and Beatrice Hunter Cancer Research Institute, Halifax, NS, Canada
| | - Graham Dellaire
- Department of Pathology, Dalhousie University, Halifax, NS, Canada and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada and Beatrice Hunter Cancer Research Institute, Halifax, NS, Canada
| | - John P Frampton
- School of Biomedical Engineering, Dalhousie University, Halifax, NS, Canada. and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS, Canada and Beatrice Hunter Cancer Research Institute, Halifax, NS, Canada
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8
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Raimundo AF, Ferreira S, Martins IC, Menezes R. Islet Amyloid Polypeptide: A Partner in Crime With Aβ in the Pathology of Alzheimer's Disease. Front Mol Neurosci 2020; 13:35. [PMID: 32265649 PMCID: PMC7103646 DOI: 10.3389/fnmol.2020.00035] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
Diabetes affects hundreds of millions of patients worldwide. Despite the advances in understanding the disease and therapeutic options, it remains a leading cause of death and of comorbidities globally. Islet amyloid polypeptide (IAPP), or amylin, is a hormone produced by pancreatic β-cells. It contributes to the maintenance of glucose physiological levels namely by inhibiting insulin and glucagon secretion as well as controlling adiposity and satiation. IAPP is a highly amyloidogenic polypeptide forming intracellular aggregates and amyloid structures that are associated with β-cell death. Data also suggest the relevance of unprocessed IAPP forms as seeding for amyloid buildup. Besides the known consequences of hyperamylinemia in the pancreas, evidence has also pointed out that IAPP has a pathological role in cognitive function. More specifically, IAPP was shown to impair the blood–brain barrier; it was also seen to interact and co-deposit with amyloid beta peptide (Aß), and possibly with Tau, within the brain of Alzheimer's disease (AD) patients, thereby contributing to diabetes-associated dementia. In fact, it has been suggested that AD results from a metabolic dysfunction in the brain, leading to its proposed designation as type 3 diabetes. Here, we have first provided a brief perspective on the IAPP amyloidogenic process and its role in diabetes and AD. We have then discussed the potential interventions for modulating IAPP proteotoxicity that can be explored for therapeutics. Finally, we have proposed the concept of a “diabetes brain phenotype” hypothesis in AD, which may help design future IAPP-centered drug developmentstrategies against AD.
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Affiliation(s)
- Ana F Raimundo
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.,ITQB-NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sofia Ferreira
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Ivo C Martins
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Regina Menezes
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.,ITQB-NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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9
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Shi T, Wu L, Ma W, Ju L, Bai M, Chen X, Liu S, Yang X, Shi J. Nonalcoholic Fatty Liver Disease: Pathogenesis and Treatment in Traditional Chinese Medicine and Western Medicine. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2020; 2020:8749564. [PMID: 31998400 PMCID: PMC6969649 DOI: 10.1155/2020/8749564] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/14/2019] [Accepted: 11/20/2019] [Indexed: 01/30/2023]
Abstract
Nonalcoholic Fatty Liver Disease (NAFLD) is one of the most important causes of liver disease worldwide and probably destined to become the leading cause of end-stage liver disease in the coming decades, affecting both adults and children. Faced with the severe challenges for the prevention and control of NAFLD, this article discusses the understanding and mechanism of NAFLD from Chinese and Western medicine. Moreover, the progress regarding its treatment in both Chinese and Western medicine is also summarized. Both Chinese medicine and Western medicine have their own characteristics and clinical efficacy advantages in treating diseases. The purpose of this article is to hope that Chinese and Western medicine have complementary advantages, complementing each other to improve clinical NAFLD therapy prevention and treatment methods to receive more and more attention throughout the global medical community.
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Affiliation(s)
- Tingting Shi
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Li Wu
- Center of Clinical Evaluation, The First Affiliated Hospital of Zhejiang Chinese Medical University, 54 Youdian Road, Hangzhou 310006, Zhejiang, China
| | - Wenjun Ma
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Liping Ju
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Minghui Bai
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Xiaowei Chen
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Shourong Liu
- The Hangzhou Xixi Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou 310023, Zhejiang, China
| | - Xingxin Yang
- College of Pharmaceutical Science, Yunnan University of Traditional Chinese Medicine, 1076 Yuhua Road, Kunming 650500, Yunnan, China
| | - Junping Shi
- Department of Liver Diseases, The Affiliated Hospital of Hangzhou Normal University, Hangzhou, Zhejiang, China
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10
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Abstract
In aerobes, oxygen is essential for maintenance of life. However, incomplete reduction of oxygen leads to generation of reactive oxygen species. These oxidants oxidise biological macromolecules present in their vicinity and thereby impair cellular functions causing oxidative stress (OS). Aerobes have evolved both enzymatic and nonenzymatic antioxidant defences to protect themselves from OS. Although hormones as means of biological coordination involve in regulation of physiological activities of tissues by regulating metabolism, any change in their normal titre leads to pathophysiological states. While, hormones such as melatonin, insulin, oestrogen, progesterone display antioxidant features, thyroid hormone, corticosteroids and catecholamines elicit free radical generation and OS, and the role of testosterone in inducing OS is debateable. This review is an attempt to understand the impact of free radical generation and cross talk between the hormones modulating antioxidant defence system under various pathophysiological conditions.
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Affiliation(s)
- Gagan B N Chainy
- Department of Biotechnology, Utkal University, Bhubaneswar, India
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11
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Yang J, Sun Y, Xu F, Liu W, Hayashi T, Hattori S, Ushiki‐Kaku Y, Onodera S, Tashiro S, Ikejima T. Silibinin protects rat pancreatic β‐cell through up‐regulation of estrogen receptors' signaling against amylin‐ or Aβ
1–42
‐induced reactive oxygen species/reactive nitrogen species generation. Phytother Res 2019; 33:998-1009. [DOI: 10.1002/ptr.6293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/30/2018] [Accepted: 12/06/2018] [Indexed: 12/17/2022]
Affiliation(s)
- Jing Yang
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Yue Sun
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Fanxing Xu
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Weiwei Liu
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
| | - Toshihiko Hayashi
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
- Department of Chemistry and Life science, School of Advanced EngineeringKogakuin University Tokyo Japan
| | - Shunji Hattori
- Nippi Research Institute of BiomatrixNippi, Incorporated Toride Japan
| | - Yuko Ushiki‐Kaku
- Nippi Research Institute of BiomatrixNippi, Incorporated Toride Japan
| | - Satoshi Onodera
- Department of Clinical and Biomedical SciencesShowa Pharmaceutical University Tokyo Japan
| | - Shin‐ichi Tashiro
- Department of Medical Education and Primary CareKyoto Prefectural University of Medicine Kyoto Japan
| | - Takashi Ikejima
- Wuya College of InnovationShenyang Pharmaceutical University Shenyang China
- Key Laboratory of Computational Chemistry‐Based Natural Antitumor Drug Research & DevelopmentShenyang Pharmaceutical University Shenyang China
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12
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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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13
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Xin Y, Wang X, Luo L, Meng F. Conformation-Dependent Manipulation of Human Islet Amyloid Polypeptide Fibrillation by Shiitake-Derived Lentinan. ACS APPLIED MATERIALS & INTERFACES 2018; 10:31069-31079. [PMID: 30148596 DOI: 10.1021/acsami.8b11078] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Misfolding and aggregation of human islet amyloid polypeptide (hIAPP) into fibrils are important contributions to the pathology of type 2 diabetes. Developing effective inhibitors of protein aggregation and fibrillation has been considered a promising therapeutic approach to preventing and treating type 2 diabetes. Herein, we report that Shiitake-derived polysaccharide lentinan manipulates in vitro hIAPP fibrillation and modulates IAPP-induced cytotoxicity in a conformation-dependent manner. In its triple-helical conformation, lentinan effectively inhibits hIAPP fibrillation, either in bulk solution or in the presence of lipid membrane, suppresses reactive oxygen species (ROS) generation, and attenuates hIAPP-induced cell toxicity. In contrast, lentinan accelerates hIAPP aggregation when it exists in a random-coil conformation and shows no suppression on hIAPP-mediated ROS production. Further investigation shows that the interaction between triple-helical lentinan and monomeric hIAPP is more favorable than the intermolecular binding of hIAPP, which redirects hIAPP aggregates to discrete nontoxic nanocomposites. To the best of our knowledge, this is the first time to report a conformation-dependent inhibition of hIAPP aggregation, which will provide new insights for our understanding of the manipulation mechanisms on hIAPP by natural polysaccharides and open a new avenue for designing and screening potential amyloid inhibitors against type 2 diabetes.
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Affiliation(s)
- Yanru Xin
- National Engineering Research Center for Nanomedicine, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Xiuxia Wang
- National Engineering Research Center for Nanomedicine, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Liang Luo
- National Engineering Research Center for Nanomedicine, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
- Wuhan Institute of Biotechnology , Wuhan 430075 , China
| | - Fanling Meng
- National Engineering Research Center for Nanomedicine, College of Life Science and Technology , Huazhong University of Science and Technology , Wuhan 430074 , China
- Wuhan Institute of Biotechnology , Wuhan 430075 , China
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14
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Xia G, Zhu T, Li X, Jin Y, Zhou J, Xiao J. ROS‑mediated autophagy through the AMPK signaling pathway protects INS‑1 cells from human islet amyloid polypeptide‑induced cytotoxicity. Mol Med Rep 2018; 18:2744-2752. [PMID: 30015901 PMCID: PMC6102651 DOI: 10.3892/mmr.2018.9248] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 03/06/2018] [Indexed: 11/27/2022] Open
Abstract
Oligomerization of human islet amyloid polypeptide (hIAPP) is toxic and contributes to progressive reduction of β cell mass in patients with type 2 diabetes mellitus. Autophagy is a highly conserved homeostatic mechanism in eukaryotes. Previous studies have confirmed that hIAPP can promote autophagy in β cells, but the underlying molecular mechanism and cellular regulatory pathway of hIAPP-induced autophagy remains not fully elucidated. Accumulation of reactive oxygen species (ROS) causes hIAPP induced-β cell death. At present, little is known about the association between hIAPP-induced oxidative stress and autophagy in β cells. Therefore, the present study investigated the underlying molecular mechanism and regulatory pathway of hIAPP-induced autophagy. Transmission electron microscopy was used to observe the number of autophagosome in cells. Cell viability was determined by an MTT test. A 2′,7′-dichlorofluorescin diacetate assay was used to measure the relative levels of reactive ROS. Western blotting was used to detect expression of adenosine monophosphate-activated protein kinase (AMPK) and autophagic markers p62 and microtubule associated protein 1 light chain 3. The results demonstrated that hIAPP induces autophagy through ROS-mediated AMPK signaling pathway in INS-1 cells. Upregulation of autophagy by AMPK activator 5-aminoimidazole-4-carboxamide1-β-D-ribofuranoside decreased ROS and malondialdehyde generation, whereas inhibition of autophagy by 3-methyladenine and AMPK inhibitor compound C aggravated hIAPP-induced oxidative stress and toxicity in INS-1 cells. Taken together, the present study suggested that hIAPP induces autophagy via a ROS-mediated AMPK signaling pathway. Furthermore, autophagy serves as a cell-protective mechanism against hIAPP-induced toxicity and chemical promotion of autophagy through AMPK signaling pathway attenuates hIAPP induced cytotoxicity and oxidative stress in INS-1 cells.
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Affiliation(s)
- Guanghao Xia
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Tiehong Zhu
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Xiaotong Li
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Yujing Jin
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Jing Zhou
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
| | - Jinfeng Xiao
- Department of Endocrinology and Metabolic Disease, Tianjin Medical University General Hospital, Tianjin 300052, P.R. China
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15
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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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16
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Abstract
The oligomerization and fibrillation of human islet amyloid polypeptide (hIAPP) play a central role in the pathogenesis of type 2 diabetes. Strategies for remodelling the formation of hIAPP oligomers and fibrils have promising application potential in type 2 diabetes therapy. Herein, we demonstrated that PEG-PE micelle could inhibit hIAPP oligomerization and fibrillation through blocking the hydrophobic interaction and the conformational change from random coil to β-sheet structures of hIAPP. In addition, we also found that PEG-PE micelle could remodel the preformed hIAPP fibrils allowing the formation of short fibrils and co-aggregates. Taken together, PEG-PE micelle could rescue hIAPP-induced cytotoxicity by decreasing the content of hIAPP oligomers and fibrils that are related to the oxidative stress and cell membrane permeability. This study could be beneficial for the design and development of antiamyloidogenic agents.
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17
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The Mitochondrial-Derived Peptides, HumaninS14G and Small Humanin-like Peptide 2, Exhibit Chaperone-like Activity. Sci Rep 2017; 7:7802. [PMID: 28798389 PMCID: PMC5552803 DOI: 10.1038/s41598-017-08372-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/11/2017] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial-derived peptides (MDPs) and their analogs have emerged as wide-spectrum, stress response factors protective in amyloid disease models. MDP cytoprotective functions are generally attributed to anti-apoptotic activity, however, little is known about their capacity to facilitate the cell’s unfolded protein response via direct interactions with amyloidogenic proteins. Here, we explored the effects of the MDP-analog, humaninS14G (HNG), and the MDP, small humanin-like peptide 2 (SHLP2), on the misfolding of islet amyloid polypeptide (IAPP), a critical pathogenic step in type 2 diabetes mellitus (T2DM). Our thioflavin T fluorescence studies show that HNG inhibits IAPP misfolding at highly substoichiometric concentrations. Seeded fluorescence and co-sedimentation studies demonstrate MDPs block amyloid seeding and directly bind misfolded, seeding-capable IAPP species. Furthermore, our electron paramagnetic resonance spectroscopy and circular dichroism data indicate MDPs do not act by binding IAPP monomers. Taken together our results reveal a novel chaperone-like activity wherein these MDPs specifically target misfolded amyloid seeds to inhibit IAPP misfolding which, along with direct anti-apoptotic activity and beneficial metabolic effects, make HNG and SHLP2 exciting prospects as T2DM therapeutics. These data also suggest that other mitochondrial stress response factors within the MDP family may be amenable to development into therapeutics for protein-misfolding diseases.
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18
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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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19
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Abedini A, Plesner A, Cao P, Ridgway Z, Zhang J, Tu LH, Middleton CT, Chao B, Sartori DJ, Meng F, Wang H, Wong AG, Zanni MT, Verchere CB, Raleigh DP, Schmidt AM. Time-resolved studies define the nature of toxic IAPP intermediates, providing insight for anti-amyloidosis therapeutics. eLife 2016; 5. [PMID: 27213520 PMCID: PMC4940161 DOI: 10.7554/elife.12977] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 05/20/2016] [Indexed: 01/04/2023] Open
Abstract
Islet amyloidosis by IAPP contributes to pancreatic β-cell death in diabetes, but the nature of toxic IAPP species remains elusive. Using concurrent time-resolved biophysical and biological measurements, we define the toxic species produced during IAPP amyloid formation and link their properties to induction of rat INS-1 β-cell and murine islet toxicity. These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species. They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure. Aromatic interactions modulate, but are not required for toxicity. Not all IAPP oligomers are toxic; toxicity depends on their partially structured conformational states. Some anti-amyloid agents paradoxically prolong cytotoxicity by prolonging the lifetime of the toxic species. The data highlight the distinguishing properties of toxic IAPP oligomers and the common features that they share with toxic species reported for other amyloidogenic polypeptides, providing information for rational drug design to treat IAPP induced β-cell death. DOI:http://dx.doi.org/10.7554/eLife.12977.001
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Affiliation(s)
- Andisheh Abedini
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Annette Plesner
- Child and Family Research Institute, Department of Pathology and Laboratory Medicine and Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Ping Cao
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Zachary Ridgway
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Jinghua Zhang
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Ling-Hsien Tu
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Chris T Middleton
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | - Brian Chao
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Daniel J Sartori
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
| | - Fanling Meng
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Hui Wang
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Amy G Wong
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Martin T Zanni
- Department of Chemistry, University of Wisconsin-Madison, Madison, United States
| | - C Bruce Verchere
- Child and Family Research Institute, Department of Pathology and Laboratory Medicine and Department of Surgery, University of British Columbia, Vancouver, Canada
| | - Daniel P Raleigh
- Department of Chemistry, Stony Brook University, Stony Brook, United States
| | - Ann Marie Schmidt
- Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States
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20
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Endothelial function does not improve with high-intensity continuous exercise training in SHR: implications of eNOS uncoupling. Hypertens Res 2015; 39:70-8. [PMID: 26537830 DOI: 10.1038/hr.2015.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/30/2015] [Accepted: 08/20/2015] [Indexed: 12/28/2022]
Abstract
Exercise training is a well-recognized way to improve vascular endothelial function by increasing nitric oxide (NO) bioavailability. However, in hypertensive subjects, unlike low- and moderate-intensity exercise training, the beneficial effects of continuous high-intensity exercise on endothelial function are not clear, and the underlying mechanisms remain unknown. The aim of this study was to investigate the impact of high-intensity exercise on vascular function, especially on the NO pathway, in spontaneous hypertensive rats (SHR). These effects were studied on WKY, sedentary SHR and SHR that exercised at moderate (SHR-MOD) and high intensity (SHR-HI) on a treadmill (1 h per day; 5 days per week for 6 weeks at 55% and 80% of their maximal aerobic velocity, respectively). Endothelial function and specific NO contributions to acetylcholine-mediated relaxation were evaluated by measuring the aortic ring isometric forces. Endothelial nitric oxide synthase (eNOS) expression and phosphorylation (ser1177) were evaluated by western blotting. The total aortic and eNOS-dependent reactive oxygen species (ROS) production was assessed using electron paramagnetic resonance in aortic tissue. Although the aortas of SHR-HI had increased eNOS levels without alteration of eNOS phosphorylation, high-intensity exercise had no beneficial effect on endothelium-dependent vasorelaxation, unlike moderate exercise. This result was associated with increased eNOS-dependent ROS production in the aortas of SHR-HI. Notably, the use of the recoupling agent BH4 or a thiol-reducing agent blunted eNOS-dependent ROS production in the aortas of SHR-HI. In conclusion, the lack of a positive effect of high-intensity exercise on endothelial function in SHR was mainly explained by redox-dependent eNOS uncoupling, resulting in a switch from NO to O2(-) generation.
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21
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Mukherjee A, Morales-Scheihing D, Butler PC, Soto C. Type 2 diabetes as a protein misfolding disease. Trends Mol Med 2015; 21:439-49. [PMID: 25998900 DOI: 10.1016/j.molmed.2015.04.005] [Citation(s) in RCA: 228] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/16/2015] [Accepted: 04/22/2015] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes (T2D) is a highly prevalent and chronic metabolic disorder. Recent evidence suggests that formation of toxic aggregates of the islet amyloid polypeptide (IAPP) might contribute to β-cell dysfunction and disease. However, the mechanism of protein aggregation and associated toxicity remains unclear. Misfolding, aggregation, and accumulation of diverse proteins in various organs is the hallmark of the group of protein misfolding disorders (PMDs), including highly prevalent illnesses affecting the central nervous system (CNS) such as Alzheimer's disease (AD) and Parkinson's disease (PD). In this review we discuss the current understanding of the mechanisms implicated in the formation of protein aggregates in the endocrine pancreas and associated toxicity in the light of the long-standing knowledge from neurodegenerative disorders associated with protein misfolding.
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Affiliation(s)
- Abhisek Mukherjee
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA
| | - Diego Morales-Scheihing
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA; Universidad de los Andes, Facultad de Medicina, Av. San Carlos de Apoquindo 2200, Las Condes, Santiago, Chile
| | - Peter C Butler
- Larry L. Hillblom Islet Research Center, University of California at Los Angeles, Los Angeles, CA, USA
| | - Claudio Soto
- Mitchell Center for Alzheimer's Disease and Related Brain Disorders, Department of Neurology, University of Texas Houston Medical School, Houston, TX 77030, USA.
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22
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Ma L, Li X, Wang Y, Zheng W, Chen T. Cu(II) inhibits hIAPP fibrillation and promotes hIAPP-induced beta cell apoptosis through induction of ROS-mediated mitochondrial dysfunction. J Inorg Biochem 2014; 140:143-52. [PMID: 25108186 DOI: 10.1016/j.jinorgbio.2014.07.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 07/04/2014] [Accepted: 07/07/2014] [Indexed: 01/05/2023]
Abstract
Human islet amyloid polypeptide (hIAPP), the major component of the amyloid deposits found in the pancreatic islets of patients with type 2 diabetes mellitus (T2DM), plays a central role in the loss of insulin-secreting pancreatic beta cells. Misfolded hIAPP fibrillating in islet beta cells may be one of the causations for T2DM. Studies have showed that fibrosis of hIAPP was inhibited by copper compounds while hIAPP-induced cytotoxicity was greatly stimulated. In this study, the suppression effects of three different forms of copper compounds CuCl2, CuSO4 and Cu(Gly)2 on amyloid fibril formation were examined in vitro. The results demonstrated that Cu(II) could interact with hIAPP to suppress the fibrosis without involvement of the anions. The fibrosis of hIAPP was inhibited by CuCl2, CuSO4 and Cu(Gly)2 with a similar degree. The particle size of hIAPP aggregates was decreased, which was further confirmed in atomic force microscopy (AFM) and transmission electron microscopy (TEM) images. Moreover, approximative cytotoxicity-enhancing levels between CuCl2, CuSO4 and Cu(Gly)2 on hIAPP were also observed in INS-1 cells. Studies on the action mechanisms displayed that copper compounds increased hIAPP-induced cytotoxicity by facilitating apoptosis-promoting effect of hIAPP, which was dominated mainly by cation. Furthermore, Cu(II)-promoted ROS overproduction and mitochondrial disruption might be the main reason for the enhanced apoptosis. Taken together, our studies demonstrate clear interaction mechanisms of Cu(II) and hIAPP in pancreatic beta cells, and provide useful information for our understanding and treatment of T2DM.
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Affiliation(s)
- Lijuan Ma
- Department of Chemistry, Jinan University, Guangzhou 510632, PR China
| | - Xiaoling Li
- Department of Chemistry, Jinan University, Guangzhou 510632, PR China
| | - Yi Wang
- Department of Chemistry, Jinan University, Guangzhou 510632, PR China
| | - Wenjie Zheng
- Department of Chemistry, Jinan University, Guangzhou 510632, PR China
| | - Tianfeng Chen
- Department of Chemistry, Jinan University, Guangzhou 510632, PR China.
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23
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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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24
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Lee EC, Ha E, Singh S, Legesse L, Ahmad S, Karnaukhova E, Donaldson RP, Jeremic AM. Copper(II)-human amylin complex protects pancreatic cells from amylin toxicity. Phys Chem Chem Phys 2014; 15:12558-71. [PMID: 23793354 DOI: 10.1039/c3cp44542a] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Human amylin-derived oligomers and aggregates are believed to play an important role in the pathogenesis of type II diabetes mellitus (T2DM). In addition to amylin-evoked cell attrition, T2DM is often accompanied by elevated serum copper levels. Although previous studies have shown that human amylin, in the course of its aggregation, produces hydrogen peroxide (H2O2) in solution, and that this process is exacerbated in the presence of copper(ii) ions (Cu(2+)), very little is known about the mechanism of interaction between Cu(2+) and amylin in pancreatic β-cells, including its pathological significance. Hence, in this study we investigated the mechanism by which Cu(2+) and human amylin catalyze formation of reactive oxygen species (ROS) in cells and in vitro, and examined the modulatory effect of Cu(2+) on amylin aggregation and toxicity in pancreatic rat insulinoma (RIN-m5F) β-cells. Our results indicate that Cu(2+) interacts with human and rat amylin to form metalo-peptide complexes with low aggregative and oxidative properties. Human and non-amyloidogenic rat amylin produced minute (nM) amounts of H2O2, the accumulation of which was slightly enhanced in the presence of Cu(2+). In a marked contrast to human and rat amylin, and in the presence of the reducing agents glutathione and ascorbate, Cu(2+) produced μM concentrations of H2O2 surpassing the amylin effect by several fold. The current study shows that human and rat amylin not only produce but also quench H2O2, and that human but not rat amylin significantly decreases the amount of H2O2 in solution produced by Cu(2+) and glutathione. Similarly, human amylin was found to also decrease hydroxyl radical formation elicited by Cu(2+) and glutathione. Furthermore, Cu(2+) mitigated the toxic effect of human amylin by inhibiting activation of pro-apoptotic caspase-3 and stress-kinase signaling pathways in rat pancreatic insulinoma cells in part by stabilizing human amylin in its native conformational state. This sacrificial quenching of metal-catalyzed ROS by human amylin and copper's anti-aggregative and anti-apoptotic properties suggest a novel and protective role for the copper-amylin complex.
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Affiliation(s)
- Elizabeth C Lee
- Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA
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Borchi E, Bargelli V, Guidotti V, Berti A, Stefani M, Nediani C, Rigacci S. Mild exposure of RIN-5F β-cells to human islet amyloid polypeptide aggregates upregulates antioxidant enzymes via NADPH oxidase-RAGE: an hormetic stimulus. Redox Biol 2013; 2:114-22. [PMID: 24416718 PMCID: PMC3887275 DOI: 10.1016/j.redox.2013.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 12/06/2013] [Accepted: 12/07/2013] [Indexed: 01/09/2023] Open
Abstract
The presence of amyloid aggregates of human islet amyloid polypeptide (hIAPP), a hallmark of type 2 diabetes, contributes to pancreatic β-cell impairment, where oxidative stress plays a key role. A contribution of NADPH oxidase to reactive oxygen species (ROS) generation after cell exposure to micromolar concentrations of hIAPP aggregates has been suggested. However, little is known about β-cells exposure to lower amounts of hIAPP aggregates, similar to those found in human pancreas. Thus, we aimed to investigate the events resulting from RIN-5F cells exposure to nanomolar concentrations of toxic hIAPP aggregates. We found an early and transient rise of NADPH oxidase activity resulting from increased Nox1 expression following the engagement of receptor for advanced glycation end-products (RAGE) by hIAPP aggregates. Unexpectedly, NADPH oxidase activation was not accompanied by a significant ROS increase and the lipoperoxidation level was significantly reduced. Indeed, cell exposure to hIAPP aggregates affected the antioxidant defences, inducing a significant increase of the expression and activity of catalase and glutathione peroxidase. We conclude that exposure of pancreatic β-cells to nanomolar concentrations of hIAPP aggregates for a short time induces an hormetic response via the RAGE-Nox1 axis; the latter stimulates the enzymatic antioxidant defences that preserve the cells against oxidative stress damage. Short time exposure of pancreatic β-cells to low hIAPP aggregate amounts is studied. NADPH oxidase activity is increased after 3 h treatment with 60 nM hIAPP aggregates. RAGE engagement by aggregates increases Nox1 expression. Reduced lipoperoxidation and increased antioxidant enzymes were observed. A protective hormetic response via RAGE-Nox1 is proposed.
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Key Words
- AGE, advanced glycation end products
- ATZ, 3-amino-1,2,4-triazole
- Antioxidant enzyme
- CAT, catalase
- DPI, diphenyleneiodonium
- GPx, glutathione peroxidase
- Hormesis
- MDA, malonyldialdehyde
- MS, mercaptosuccinic acid
- NADPH oxidase
- RAGE
- RAGE, receptor for advanced glycation end-products
- ROS, reactive oxygen species
- SOD, superoxide dismutase
- Type 2 diabetes
- hIAPP
- hIAPP, human islet amyloid polypeptide
- rIAPP, rat islet amyloid polypeptide
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Affiliation(s)
- Elisabetta Borchi
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Valentina Bargelli
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Valentina Guidotti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Andrea Berti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy ; Research Centre on the Molecular Basis of Neurodegeneration (CIMN), Viale Morgagni 50, 50134 Florence, Italy
| | - Massimo Stefani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy ; Research Centre on the Molecular Basis of Neurodegeneration (CIMN), Viale Morgagni 50, 50134 Florence, Italy ; National Institute of Biostructures and Biosystems (INBB), Viale Medaglie d'Oro 305, Rome, Italy
| | - Chiara Nediani
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
| | - Stefania Rigacci
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Florence, Italy
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Amylin uncovered: a review on the polypeptide responsible for type II diabetes. BIOMED RESEARCH INTERNATIONAL 2013; 2013:826706. [PMID: 23607096 PMCID: PMC3626316 DOI: 10.1155/2013/826706] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 02/21/2013] [Indexed: 11/17/2022]
Abstract
Amylin is primarily responsible for classifying type II diabetes as an amyloid (protein misfolding) disease as it has great potential to aggregate into toxic nanoparticles, thereby resulting in loss of pancreatic β-cells. Although type II diabetes is on the increase each year, possibly due to bad eating habits of modern society, research on the culprit for this disease is still in its early days. In addition, unlike the culprit for Alzheimer's disease, amyloid β-peptide, amylin has failed to receive attention worthy of being featured in an abundance of review articles. Thus, the aim of this paper is to shine the spotlight on amylin in an attempt to put it onto the top of researchers' to-do list since the secondary complications of type II diabetes have far-reaching and severe consequences on public health both in developing and fully developed countries alike. This paper will cover characteristics of the amylin aggregates, mechanisms of toxicity, and a particular focus on inhibitors of toxicity and techniques used to assess these inhibitors.
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Bahramikia S, Yazdanparast R. Inhibition of human islet amyloid polypeptide or amylin aggregation by two manganese-salen derivatives. Eur J Pharmacol 2013; 707:17-25. [PMID: 23528352 DOI: 10.1016/j.ejphar.2013.03.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 03/09/2013] [Accepted: 03/13/2013] [Indexed: 10/27/2022]
Abstract
Aggregation of human islet amyloid polypeptide (IAPP) into pancreatic fibrillar deposits has been postulated to be one of the main contributors to impaired insulin secretion and pancreatic β-cell death in approximately 90% of type 2 diabetic patients. So, compounds that prevent cytotoxic protein/polypeptide self-assembly and amyloidogenesis are considered as novel therapeutic agents against this disease. In this study, using thioflavin-T (ThT) and Anilinonaphthalene-8-sulfonic acid (ANS) fluorescence assays, transmission electron microscopy (TEM) and docking studies, we investigated whether EUK-8 and EUK-134, two salen derivatives with proven antioxidants activities, could interfere with the conversion of synthetic human amylin to its insoluble amyloid form. Spectroscopy and electron microscopy data indicated that incubation of human amylin with either EUK-8 or EUK-134 significantly inhibited amyloid formation at two molar ratios of 1:1 and 5:1 (drugs to protein). In addition, [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) assay showed that treatment of SK-N-MC cells with the pre-formed fibrils in the presence of compounds at drug-to-protein molar ratios of 1:1 and 5:1, dramatically increased the viability of cells compared to the only fibrils formed-treated SK-N-MC cells. Docking results also demonstrated that the aromatic rings of EUK-8 and EUK-134 interact with the hydrophobic region (23-25) of IAPP via Van der Waals interactions. Based on these results and the proven antioxidant properties of these compounds, it could be concluded that these compounds might provide a novel approach to prevent islet amyloid deposition in β-cells and provide useful information for developing other novel compounds for the treatment of type 2 diabetes.
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Affiliation(s)
- Seifollah Bahramikia
- Institute of Biochemistry and Biophysics, PO Box 13145-1384, University of Tehran, Enghelab Ave, Tehran, Iran
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Redox homeostasis in pancreatic β cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2012; 2012:932838. [PMID: 23304259 PMCID: PMC3532876 DOI: 10.1155/2012/932838] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/30/2012] [Indexed: 12/20/2022]
Abstract
We reviewed mechanisms that determine reactive oxygen species (redox) homeostasis, redox information signaling and metabolic/regulatory function of autocrine insulin signaling in pancreatic β cells, and consequences of oxidative stress and dysregulation of redox/information signaling for their dysfunction. We emphasize the role of mitochondrion in β cell molecular physiology and pathology, including the antioxidant role of mitochondrial uncoupling protein UCP2. Since in pancreatic β cells pyruvate cannot be easily diverted towards lactate dehydrogenase for lactate formation, the respiration and oxidative phosphorylation intensity are governed by the availability of glucose, leading to a certain ATP/ADP ratio, whereas in other cell types, cell demand dictates respiration/metabolism rates. Moreover, we examine the possibility that type 2 diabetes mellitus might be considered as an inevitable result of progressive self-accelerating oxidative stress and concomitantly dysregulated information signaling in peripheral tissues as well as in pancreatic β cells. It is because the redox signaling is inherent to the insulin receptor signaling mechanism and its impairment leads to the oxidative and nitrosative stress. Also emerging concepts, admiting participation of redox signaling even in glucose sensing and insulin release in pancreatic β cells, fit in this view. For example, NADPH has been firmly established to be a modulator of glucose-stimulated insulin release.
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29
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Overlapped Metabolic and Therapeutic Links between Alzheimer and Diabetes. Mol Neurobiol 2012; 47:399-424. [DOI: 10.1007/s12035-012-8352-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 09/12/2012] [Indexed: 12/12/2022]
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Hu J, Yu YP, Cui W, Fang CL, Wu WH, Zhao YF, Li YM. Cyclen-hybrid compound captures copper to protect INS-1 cells from islet amyloid polypeptide cytotoxicity by inhibiting and lysing effects. Chem Commun (Camb) 2010; 46:8023-5. [PMID: 20856987 DOI: 10.1039/c0cc02555k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) deposit is the hallmark of type 2 diabetes pathology. Here, we report that apo-cyclen, attached to a specific hIAPP recognition motif (NYGAIL), captured copper ions and became proteolytically active. This cyclen-NYGAIL-copper complex was able to interfere with hIAPP aggregation and cleave hIAPP. These activities rescued INS-1 cells from hIAPP induced cytotoxicity.
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Affiliation(s)
- Jia Hu
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
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Güney O, Erdi F, Esen H, Kiyici A, Kocaogullar Y. N-acetylcysteine prevents vasospasm after subarachnoid hemorrhage. World Neurosurg 2009; 73:42-9; discussion e3. [PMID: 20452867 DOI: 10.1016/j.surneu.2009.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Accepted: 06/04/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND This study investigated the ability of NAC to prevent cerebral vasospasm in a rabbit model of SAH. METHODS Twenty-one, male New Zealand white rabbits were randomly divided into 3 groups of 7 rabbits each: group 1 (control), group 2 (SAH only), group 3 (SAH + NAC treatment). NAC (150 mg/kg, single dose, IP) was administered just before SAH and continued until 72 hours after SAH in group 3. Animals were killed 72 hours after SAH. Tissue MDA levels, SOD, and GSH-Px activities were measured, and basilar artery cross-sectional areas, arterial wall thickness, and endothelial apoptosis in a cross section of basillary artery were determined in all groups. RESULTS Intraperitoneal administration of NAC was found to be markedly effective against developing a cerebral vasospasm following a SAH in rabbits. It could significantly reduce elevated lipid peroxidation and increase the level of tissue GSH-Px and SOD enzymatic activities. Also, NAC treatment was found to be effective in increasing the luminal area and reducing wall thickness of the basilar artery. The morphology of arteries in the NAC treatment group was well protected. NAC markedly reduced apoptotic index and protects the endothelial integrity. CONCLUSIONS This study demonstrates, for the first time, that NAC treatment attenuates cerebral vasospasm in a rabbit SAH model. NAC treatment has significant neuroprotective effect and markedly prevents cerebral vasospasm after SAH. In conclusion, the NAC treatment might be beneficial in preventing cerebral vasospasm after SAH, thus showing potential for clinical implications.
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Affiliation(s)
- Onder Güney
- Department of Neurosurgery, Selcuk University Meram Faculty of Medicine, Konya, Turkey.
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32
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Li XL, Xu G, Chen T, Wong YS, Zhao HL, Fan RR, Gu XM, Tong PC, Chan JC. Phycocyanin protects INS-1E pancreatic beta cells against human islet amyloid polypeptide-induced apoptosis through attenuating oxidative stress and modulating JNK and p38 mitogen-activated protein kinase pathways. Int J Biochem Cell Biol 2009; 41:1526-35. [PMID: 19166964 DOI: 10.1016/j.biocel.2009.01.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 12/22/2008] [Accepted: 01/05/2009] [Indexed: 12/20/2022]
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Zraika S, Hull RL, Udayasankar J, Aston-Mourney K, Subramanian SL, Kisilevsky R, Szarek WA, Kahn SE. Oxidative stress is induced by islet amyloid formation and time-dependently mediates amyloid-induced beta cell apoptosis. Diabetologia 2009; 52:626-35. [PMID: 19148619 PMCID: PMC2719780 DOI: 10.1007/s00125-008-1255-x] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Accepted: 12/12/2008] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Islet amyloid in type 2 diabetes contributes to loss of beta cell mass and function. Since islets are susceptible to oxidative stress-induced toxicity, we sought to determine whether islet amyloid formation is associated with induction of oxidative stress. METHODS Human islet amyloid polypeptide transgenic and non-transgenic mouse islets were cultured for 48 or 144 h with or without the antioxidant N-acetyl-L: -cysteine (NAC) or the amyloid inhibitor Congo Red. Amyloid deposition, reactive oxygen species (ROS) production, beta cell apoptosis, and insulin secretion, content and mRNA were measured. RESULTS After 48 h, amyloid deposition was associated with increased ROS levels and increased beta cell apoptosis, but no change in insulin secretion, content or mRNA levels. Antioxidant treatment prevented the rise in ROS, but did not prevent amyloid formation or beta cell apoptosis. In contrast, inhibition of amyloid formation prevented the induction of oxidative stress and beta cell apoptosis. After 144 h, amyloid deposition was further increased and was associated with increased ROS levels, increased beta cell apoptosis and decreased insulin content. At this time-point, antioxidant treatment and inhibition of amyloid formation were effective in reducing ROS levels, amyloid formation and beta cell apoptosis. Inhibition of amyloid formation also increased insulin content. CONCLUSIONS/INTERPRETATION Islet amyloid formation induces oxidative stress, which in the short term does not mediate beta cell apoptosis, but in the longer term may feed back to further exacerbate amyloid formation and contribute to beta cell apoptosis.
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Affiliation(s)
- S Zraika
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington and VA Puget Sound Health Care System, 1660 South Columbian Way (151), Seattle, WA 98108, USA.
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Hu Y, Liang WM. Expression of islet amyloid polypeptide in duodenum of rabbits during the postnatal development period. Shijie Huaren Xiaohua Zazhi 2009; 17:910-913. [DOI: 10.11569/wcjd.v17.i9.910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the expression and distribution features of islet amyloid polypeptide (IAPP) in duodenum of rabbits during the postnatal development period.
METHODS: Sixty rabbits were equally divided into the 5th, 15th, 25th, 35th, 60th, and 90th d groups. Immunohistochemical SABC staining and image analysis were performed to detect the expression of IAPP.
RESULTS: The expression of IAPP was found in the duodenum of rabbits at different postnatal development stages. Positive production was brownish-yellow and resided in the cytoplasm. In the 5th and 15th d groups, a few IAPP positive cells scattered over epithelium mucosa cells, and the staining was weaker. During 25th to 90th d, the number of IAPP positive cells increased and staining became stronger gradually. The positive cells were mainly distributed in the connective tissue of tunica propria, and some cells scattered over epithelium mucosa cells. The result of image analysis indicated the number of IAPP positive cells increased from 35th to 90th d (F = 24.19, P = 0.0001), and the mean grey values decreased gradually from 15th d (F = 72.42, P = 0.004).
CONCLUSION: IAPP maybe involve in the development of tunica mucosa in rabbit duodenum as a nutrition factor.
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Ortega JA, Ortega JM, Julian D. Hypotaurine and sulfhydryl-containing antioxidants reduce H2S toxicity in erythrocytes from a marine invertebrate. J Exp Biol 2008; 211:3816-25. [DOI: 10.1242/jeb.021303] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
SUMMARY
Hypotaurine (HT) has been proposed to reduce sulfide toxicity in some deep-sea invertebrates by scavenging free radicals produced from sulfide oxidation or by scavenging sulfide via the reaction of HT with sulfide, forming thiotaurine (ThT). We tested whether HT or several antioxidants could reduce the total dissolved sulfide concentration in buffered seawater exposed to H2S, and whether HT, ThT or antioxidants could increase the viability of Glycera dibranchiataerythrocytes exposed to H2S in vitro. We found that 5 and 50 mmol l–1 HT reduced the dissolved sulfide in cell-free buffer exposed to H2S by up to 80% whereas the antioxidants glutathione ethyl ester (GEE), N-acetylcysteine (NAC), l-ascorbic acid (ASC), Tempol and Trolox had no consistent effect. Exposure of erythrocytes to 0.10%–3.2% H2S (producing 0.18–4.8 mmol l–1 sulfide) decreased the fraction of viable cells, as evidenced by loss of plasma membrane integrity, with virtually no cells remaining viable at 1.0% or more H2S. Addition of HT (0.5–50 mmol l–1) significantly increased the fraction of viable cells (e.g. from 0.01 to 0.84 at 0.32% H2S) whereas ThT (0.5 and 5 mmol l–1) decreased cell viability. GEE (0.03–3 mmol l–1) and NAC (0.001–1 mmol l–1), which contain sulfhydryl groups, increased cell viability during H2S exposure but to a lesser extent than HT whereas ASC, Tempol and Trolox, which do not contain sulfhydryl groups, decreased viability or had no effect. These data show that HT can protect cells from sulfide in vitro and suggest that sulfide scavenging, rather than free radical scavenging, is the most important mechanism of protection.
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Affiliation(s)
- J. A. Ortega
- University of Florida, P.O. Box 118525, Department of Zoology,Gainesville, FL 32611, USA
| | - J. M. Ortega
- University of Florida, P.O. Box 118525, Department of Zoology,Gainesville, FL 32611, USA
| | - D. Julian
- University of Florida, P.O. Box 118525, Department of Zoology,Gainesville, FL 32611, USA
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Onoue S, Hanato J, Yamada S. Pituitary adenylate cyclase-activating polypeptide attenuates streptozotocin-induced apoptotic death of RIN-m5F cells through regulation of Bcl-2 family protein mRNA expression. FEBS J 2008; 275:5542-51. [PMID: 18959742 DOI: 10.1111/j.1742-4658.2008.06672.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Oxidative stress, followed by the apoptotic death of pancreatic beta cells, is considered to be one of causative agents in the evolution of the type 2 diabetic state; therefore, the protection of beta cells can comprise an efficacious strategy for preventing type 2 diabetes. In the present study, RIN-m5F cells (i.e. the rat insulinoma beta cell line) were stimulated with streptozotocin, resulting in a time- and concentration-dependent release of lactate dehydrogenase. There appeared to be significant apoptotic cell death after 2 h of treatment with streptozotocin at 10 mM, as demonstrated by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling staining and 2.6-fold activation of cellular caspase-3, an apoptotic enzyme. By contrast, some neuropeptides of the glucagon-secretin family and coenzyme Q(10), an endogenous mitochondrial antioxidant, could attenuate streptozotocin cytotoxicity, and especially pituitary adenylate cyclase-activating polypeptide (PACAP), at a concentration of 10(-7) M, exhibited 34% attenuation of lactate dehydrogenase release from streptozotocin-treated RIN-m5F cells. Quantitative RT-PCR experiments indicated the inhibitory effect of PACAP on streptozotocin-evoked up-regulation of pro-apoptotic factor (Noxa and Bax) and a 2.3-fold enhancement of Bcl-2 mRNA expression, a pro-survival protein, was also observed after addition of PACAP. The data obtained suggest the anti-apoptotic role of PACAP in streptozotocin-treated RIN-m5F cells through the regulation of pro-apoptotic and pro-survival factors.
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Affiliation(s)
- Satomi Onoue
- Department of Pharmacokinetics and Pharmacodynamics and Global Center of Excellence Program, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
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Milardi D, Pappalardo M, Pannuzzo M, Grasso DM, Rosa CL. The role of the Cys2-Cys7 disulfide bridge in the early steps of Islet amyloid polypeptide aggregation: A molecular dynamics study. Chem Phys Lett 2008. [DOI: 10.1016/j.cplett.2008.07.110] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Han YH, Kim SH, Kim SZ, Park WH. Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) as an O2(*-) generator induces apoptosis via the depletion of intracellular GSH contents in Calu-6 cells. Lung Cancer 2008; 63:201-9. [PMID: 18585819 DOI: 10.1016/j.lungcan.2008.05.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 04/22/2008] [Accepted: 05/05/2008] [Indexed: 01/14/2023]
Abstract
Carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) is an uncoupler of mitochondrial oxidative phosphorylation in eukaryotic cells. Here, we investigated an involvement of O(2)(*-) and GSH in FCCP-induced Calu-6 cell death and examined whether ROS scavengers rescue cells from FCCP-induced cell death. Levels of intracellular O(2)(*-) were markedly increased depending on the concentrations (5-100 microM) of FCCP. A depletion of intracellular GSH content was also observed after exposing cells to FCCP. Stable SOD mimetics, Tempol and Tiron did not change the levels of intracellular O(2)(*-), apoptosis and the loss of mitochondrial membrane potential (DeltaPsi(m)). Treatment with thiol antioxidants, NAC and DTT, showed the recovery of GSH depletion and the reduction of O(2)(*-) levels in FCCP-treated cells, which were accompanied by the inhibition of apoptosis. In contrast, BSO, a well-known inhibitor of GSH synthesis, aggravated GSH depletion, oxidative stress of O(2)(*-) and cell death in FCCP-treated cells. Taken together, our data suggested that FCCP as an O(2)(*-) generator, induces apoptosis via the depletion of intracellular GSH contents in Calu-6 cells.
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Affiliation(s)
- Yong Hwan Han
- Department of Physiology, Medical School, Institute for Medical Sciences, Center for Healthcare Technology Development, Chonbuk National University, Jeonju 561-180, Republic of Korea
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Fanélus I, Desrosiers RR. Reactive oxygen species generated by thiol-modifying phenylarsine oxide stimulate the expression of protein L-isoaspartyl methyltransferase. Biochem Biophys Res Commun 2008; 371:203-8. [PMID: 18407833 DOI: 10.1016/j.bbrc.2008.04.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/01/2008] [Indexed: 12/01/2022]
Abstract
Expression of the repair enzyme protein L-isoaspartyl methyltransferase (PIMT) has been reported to play important roles in brain. However, little is known about the regulation of PIMT expression following protein damage by oxidation in brain. Phenylarsine oxide (PAO) is an arsenical compound that alters proteins by forming disulfide bond with vicinal cysteinyl residues. Here we report that PIMT was rapidly up-regulated by PAO in U-87 human astroglioma cells. We also confirmed that PIMT up-regulation by PAO was mediated by the reaction with vicinal cysteines. Furthermore, we showed that PIMT induction by PAO was dependent on formation of reactive oxygen species (ROS). Crucially, both ROS formation and PIMT induction by PAO were inhibited by antioxidant N-acetyl-L-cysteine and NADPH oxidase inhibitor diphenyleneiodonium chloride. Importantly, down-regulation of PIMT by siRNA strikingly enhanced PAO-induced ROS. Together, these results highlight that PIMT expression is regulated by ROS and could primarily act as an antioxidant enzyme.
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Affiliation(s)
- Irvens Fanélus
- Université du Québec à Montréal, Département de chimie, C.P. 8888, Succursale Centre-Ville, Montréal, Que., Canada H3C 3P8
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Zhang S, Liu H, Yu H, Cooper GJS. Fas-associated death receptor signaling evoked by human amylin in islet beta-cells. Diabetes 2008; 57:348-56. [PMID: 17977957 DOI: 10.2337/db07-0849] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Aggregation of human amylin (hA) into beta-sheet-containing oligomers is linked to islet beta-cell dysfunction and the pathogenesis of type 2 diabetes. Here, we investigated possible contributions of Fas-associated death-receptor signaling to the mechanism of hA-evoked beta-cell apoptosis. RESEARCH DESIGN AND METHODS We measured responses to hA in isolated mouse islets and two insulinoma cell lines, wherein we measured Fas/Fas ligand (FasL) and Fas-associated death domain (FADD) expression by quantitative RT-PCR, Western blotting, and immunofluorescence staining. We used two anti-Fas/FasL blocking antibodies and the Fas/FasL antagonist Kp7-6 to probe roles of Fas interactions in the regulation of apoptosis in hA-treated beta-cells and measured Kp7-6-mediated effects on beta-sheet formation and aggregation using circular dichroism and thioflavin-T binding. RESULTS hA treatment stimulated Fas and FADD expression in beta-cells. Both blocking antibodies suppressed hA-evoked apoptosis but did not modify its aggregation. Therefore, Fas receptor interactions played a critical role in induction of this pathway. Interestingly, hA-evoked beta-cell apoptosis was suppressed and rescued by Kp7-6, which also impaired hA beta-sheet formation. CONCLUSIONS This is the first report linking hA-evoked induction and activation of Fas and FADD to beta-cell apoptosis. We have identified a Fas/FasL antagonist, Kp7-6, as a potent inhibitor of hA aggregation and related beta-cell death. These results also support an interaction between hA and Fas on the surface of apoptotic beta-cells. Increased expression and activation of Fas in beta-cells could constitute a molecular event common to the pathogenesis of both type 1 and type 2 diabetes, although the mode of pathway activation may differ between these common forms of diabetes.
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Affiliation(s)
- Shaoping Zhang
- School of Biological Sciences, University of Auckland, Level 4, 3A Symonds St., Private Bag 92019, Auckland 1142, New Zealand
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Shao J, White CC, Dabrowski MJ, Kavanagh TJ, Eckert ML, Gallagher EP. The role of mitochondrial and oxidative injury in BDE 47 toxicity to human fetal liver hematopoietic stem cells. Toxicol Sci 2007; 101:81-90. [PMID: 17916640 DOI: 10.1093/toxsci/kfm256] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The polybrominated diphenyl ethers (PBDEs) are a group of flame retardants whose residues have markedly increased in the environment and in human tissues during the last decade. Of the various congeners, BDE 47 (2,2',4,4'-tetrabromodiphenyl ether) is typically the predominant congener observed in fish and wildlife samples, as well as in human tissues. Several studies indicate in utero transfer of PBDEs during pregnancy with residues accumulating in fetal tissues, and thus the potential for BDE 47-mediated injury in utero is of concern. In this study, we examined the mechanisms of BDE 47-mediated injury to primary human fetal liver hematopoietic stem cells (HSCs), which comprise a large proportion of fetal hepatic cells and play a key role in hematopoiesis during fetal development. Incubation of fetal liver HSCs with BDE 47 led to a loss of mitochondrial membrane potential and the onset of apoptosis. These effects were observed in the low micromolar range of BDE 47 exposures. At higher concentrations, BDE 47 elicited a loss of viability, which was accompanied by the generation of reactive oxygen species and peroxidation of HSC lipids. Preincubation of fetal liver HSCs with N-acetylcysteine, a glutathione (GSH) precursor, caused an increase in cellular GSH concentrations, restored mitochondrial redox status, and ameliorated the toxicity of BDE 47. BDE 47-mediated cytotoxicity or oxidative injury was not evident at the lower concentrations (< 1microM). Collectively, these data support a role for oxidative stress in the cytotoxicity of BDE 47 and indicate that oxidative stress-associated biomarkers may be useful in assessing the sublethal effects of BDE 47 toxicity in other models. However, the fact that BDE 47 undergoes a concentration-dependent accumulation in other primary cells in media that can underestimate cellular concentrations (W. R. Mundy et al., 2004, Toxicol. Sci. 82, 164-169) suggests that the HSC cell injury observed in our study may be of less relevance to human in utero PBDE exposures.
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Affiliation(s)
- Jing Shao
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington 98105, USA
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San-Miguel B, Alvarez M, Culebras JM, González-Gallego J, Tuñón MJ. N-acetyl-cysteine protects liver from apoptotic death in an animal model of fulminant hepatic failure. Apoptosis 2007; 11:1945-57. [PMID: 17021698 DOI: 10.1007/s10495-006-0090-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND This work was undertaken to investigate whether treatment with N-acetyl-cysteine (NAC) prevents oxidative stress and inhibits the apoptotic pathways in an animal model of fulminant hepatic failure. METHODS Rabbits were experimentally infected with 2x10(4) hemagglutination units of a rabbit hemorrhagic disease virus isolate. RESULTS The spontaneous mortality rate of infected animals was 67% at 36 h post infection (pi) and 90% at 48 h pi. This percentage decreased significantly in animals receiving an i.p. injection of NAC (150 mg/kg body way/daily), for 7 days prior to infection. From 36 h pi marked increases were detected in blood levels of transaminases, lactate dehydrogenase, bilirubin and the oxidised/reduced glutathione ratio. All these effects were significantly prevented by NAC treatment. The Bax to Bcl-2 relative expression, the expression of FasL, cytochrome c and PARP-1, and the activity of caspase 3 were significantly increased at 36 and 48 h pi in infected animals. These changes were markedly reduced in animals treated with NAC, with the exception of FasL. CONCLUSION Our results suggest a potential hepatoprotective role of NAC in fulminant hepatic failure, mediated partially through the modulation of the intrinsic pathway of apoptosis.
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Affiliation(s)
- B San-Miguel
- Department of Physiology, University of León, 24071, León, Spain
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43
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Masad A, Hayes L, Tabner BJ, Turnbull S, Cooper LJ, Fullwood NJ, German MJ, Kametani F, El-Agnaf OMA, Allsop D. Copper-mediated formation of hydrogen peroxide from the amylin peptide: a novel mechanism for degeneration of islet cells in type-2 diabetes mellitus? FEBS Lett 2007; 581:3489-93. [PMID: 17617411 DOI: 10.1016/j.febslet.2007.06.061] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 06/24/2007] [Indexed: 10/23/2022]
Abstract
Amyloid deposits derived from the amylin peptide accumulate within pancreatic islet beta-cells in most cases of type-2 diabetes mellitus (T2Dm). Human amylin 'oligomers' are toxic to these cells. Using two different experimental techniques, we found that H(2)O(2) was generated during the aggregation of human amylin into amyloid fibrils. This process was greatly stimulated by Cu(II) ions, and human amylin was retained on a copper affinity column. In contrast, rodent amylin, which is not toxic, failed to generate any H(2)O(2) and did not interact with copper. We conclude that the formation of H(2)O(2) from amylin could contribute to the progressive degeneration of islet cells in T2Dm.
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Affiliation(s)
- Atef Masad
- Biomedical Sciences Unit, Department of Biological Sciences, Lancaster University, Lancaster, UK
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Novials A, Rodriguez-Mañas L, Chico A, El Assar M, Casas S, Gomis R. Amylin and hypertension: association of an amylin -G132A gene mutation and hypertension in humans and amylin-induced endothelium dysfunction in rats. J Clin Endocrinol Metab 2007; 92:1446-50. [PMID: 17213278 DOI: 10.1210/jc.2006-1980] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Amylin has been linked to the development of hypertension in several pathological states related to hypertension and insulin resistance, although there is scant data regarding its potential mechanisms of action. The -132 G/A mutation located within an activator domain of the amylin gene's promoter was first identified in a small cohort of Spanish patients with type 2 diabetes. OBJECTIVE The objective of the study was to test the interference of amylin peptide with endothelium-dependent responses as an added potential mechanism for amylin-induced hypertension. DESIGN A total of 384 patients with type 2 diabetes and 207 healthy controls were subjected to clinical analysis and genetic screening for the -132 G/A mutation of the amylin gene. The effect of amylin on endothelium-dependent responses was analyzed in aortic rings and mesenteric microvessels from nondiabetic rats. RESULTS The prevalence of the mutation was 10.1 vs. 0.9% in the control population (P<0.001). Hypertension was higher in a diabetic population carrying the mutation than in diabetic noncarriers (74 vs. 57%; P<0.05). Diabetic carriers showed higher fasting amylin levels than diabetic noncarriers (11.4+/-7 vs. 8.2+/-3 pmol/liter; P<0.05). Preincubation with 20 pmol/liter amylin impaired the relaxant responses induced by acetylcholine in rat aorta and mesenteric microvessels. This effect was abolished in both vascular beds in the presence of 100 micromol/liter NG-nitro-L-arginine methyl ester. CONCLUSIONS We propose that amylin levels and hypertension may be linked by a novel mechanism involving the capacity of amylin to induce endothelial dysfunction by interfering with nitric oxide-mediated responses.
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Affiliation(s)
- Anna Novials
- Institute of Diabetes, Sardà Farriol Foundation, Passeig Bonanova 69, 6th floor, 08017 Barcelona, Spain.
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MASUKI K, NOMURA Y, BHAWAL UK, SAWAJIRI M, HIRATA I, NAHARA Y, OKAZAKI M. Apototic and Necrotic Influence of Dental Resin Polymerization Initiators in Human Gingival Fibroblast Cultures. Dent Mater J 2007; 26:861-9. [DOI: 10.4012/dmj.26.861] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Konarkowska B, Aitken JF, Kistler J, Zhang S, Cooper GJS. The aggregation potential of human amylin determines its cytotoxicity towards islet beta-cells. FEBS J 2006; 273:3614-24. [PMID: 16884500 DOI: 10.1111/j.1742-4658.2006.05367.x] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human amylin is a small fibrillogenic protein that is the major constituent of pancreatic islet amyloid, which occurs in most subjects with type 2 diabetes. There is evidence that it can elicit in vitro apoptosis in islet beta-cells, but the physical properties that underpin its cytotoxicity have not been clearly elucidated. Here we employed electron microscopy, thioflavin T fluorescence and CD spectroscopy to analyze amylin preparations whose cytotoxic potential was established by live-dead assay in cultured beta-cells. Highly toxic amylin contained few preformed fibrils and initially showed little beta-sheet content, but underwent marked time-dependent aggregation and beta-conformer formation following dissolution. By contrast, low-toxicity amylin contained abundant preformed fibrils, and demonstrated high initial beta-sheet content but little propensity to aggregate further once dissolved. Thus, mature amylin fibrils are not toxic to beta-cells, and aggregates of fibrils such as occur in pancreatic islet amyloid in vivo are unlikely to contribute to beta-cell loss. Rather, the toxic molecular species is likely to comprise soluble oligomers with significant beta-sheet content. Attempts to find ways of protecting beta-cells from amylin-mediated death might profitably focus on preventing the conformational change from random coil to beta-sheet.
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Affiliation(s)
- Barbara Konarkowska
- School of Biological Sciences, Faculty of Science, University of Auckland, New Zealand
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Hsueh W. Genetic discoveries as the basis of personalized therapy: rosiglitazone treatment of Alzheimer's disease. THE PHARMACOGENOMICS JOURNAL 2006; 6:222-4. [PMID: 16865098 DOI: 10.1038/sj.tpj.6500383] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Zhang S, Liu H, Liu J, Tse CA, Dragunow M, Cooper GJS. Activation of activating transcription factor 2 by p38 MAP kinase during apoptosis induced by human amylin in cultured pancreatic beta-cells. FEBS J 2006; 273:3779-91. [PMID: 16869889 DOI: 10.1111/j.1742-4658.2006.05386.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Amylin-mediated islet beta-cell death is implicated in diabetogenesis. We previously reported that fibrillogenic human amylin (hA) evokes beta-cell apoptosis through linked activation of Jun N-terminal kinase 1 (JNK 1) and a caspase cascade. Here we show that p38 kinase [p38 mitogen-activated protein (MAP) kinase] became activated by hA treatment of cultured beta-cells whereas extracellular signal-regulated kinase (ERK) did not; by contrast, nonfibrillogenic rat amylin (rA) altered neither. Pretreatment with the p38 kinase-inhibitor SB203580 decreased hA-induced apoptosis and caspase-3 activation by approximately 30%; as did combined SB203580 and JNK inhibitor I, by about 70%; and the combination of SB203580, the JNK inhibitor I and a caspase-8 inhibitor, by 100%. These findings demonstrate the requirement for concurrent activation of the p38 kinase, JNK and caspase-8 pathways. We further showed that hA elicits time-dependent activation of activating transcription factor 2 (ATF-2), which was largely suppressed by SB203580, indicating that this activation is catalyzed mainly by p38 kinase. Furthermore, hA-induced apoptosis was suppressed by specific antisense ATF-2, and increased phospho-ATF-2 (p-ATF-2) was associated with increased CRE (cAMP-response element) DNA binding and CRE-mediated transcriptional activity, as well as enhancement of c-jun promoter activation. We also detected changes in the phosphorylation status and composition of the CRE complex that may play important roles in regulation of distinct downstream target genes. These studies establish p38 MAP kinase-mediated activation of ATF-2 as a significant mechanism in hA-evoked beta-cell death, which may serve as a target for pharmaceutical intervention and effective suppression of beta-cell failure in type-2 diabetes.
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Affiliation(s)
- Shaoping Zhang
- The School of Biological Sciences, Faculty of Science, University of Auckland, New Zealand
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