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Jotha-Mattos L, Vieira AB, Castelo MDSM, Queiroz ASDM, de Souza HJM, de Alencar NX, Lima LMTR. Amyloidogenesis of feline amylin and plasma levels in cats with diabetes mellitus or pancreatitis. Domest Anim Endocrinol 2021; 74:106532. [PMID: 32841886 DOI: 10.1016/j.domaniend.2020.106532] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/24/2020] [Accepted: 07/25/2020] [Indexed: 12/12/2022]
Abstract
Amylin is a pancreatic hormone cosecreted along with insulin and involved in pancreatic amyloidosis and β-cell apoptosis in diabetic cats and humans. Amylin is usually elevated in early stages of type 2 diabetes but recently was found to be increased in acute and chronic pancreatitis in humans. Currently, there are little data about feline amylin propensity to fibrillate and no information on circulating levels of this hormone during feline pancreatitis. We compared 4 amylin analogues and found cat amylin to be more prone to amyloid fibrillation than human amylin, the triple-proline analogue pramlintide and rat amylin. We also measured plasma amylin levels in healthy lean cats, diabetic cats, and cats with pancreatitis. Plasma amylin was higher in diabetic cats compared with healthy lean cats (P < 0.001). Interestingly, amylin levels during pancreatitis were higher than those of both lean cats (P < 0.0001) and diabetic cats without pancreatitis (P < 0.005). These data support evidence of feline amylin being more prone to aggregation than human amylin in vitro, which may influence diabetes mellitus progression and β-cell failure in vivo. Furthermore, our data show an increase in amylin levels during feline pancreatitis and the need for future research on the role of this hormone in the pathogenesis of pancreatic inflammation associated to feline diabetes mellitus.
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Affiliation(s)
- L Jotha-Mattos
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Bss24, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil
| | - A B Vieira
- Biomedical Department, Ross University School of Veterinary Medicine, PO Box 334, Basseterre, St. Kitts, West Indies.
| | - M da S M Castelo
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - A S de M Queiroz
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - H J M de Souza
- Escola de Medicina Veterinária, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ, Brazil
| | - N X de Alencar
- Universidade Federal Fluminense (UFF), Faculdade de Veterinária, R. Vital Brazil Filho, 64 - Santa Rosa, Niterói, RJ 24230-340, Brazil
| | - L M T R Lima
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro (UFRJ), CCS, Bss24, Ilha do Fundão, 21941-902 Rio de Janeiro, RJ, Brazil; Laboratory for Macromolecules, (LAMAC-DIMAV), National Institute for Metrology, Quality and Technology - INMETRO, Rio de Janeiro, Brazil.
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Raleigh D, Zhang X, Hastoy B, Clark A. The β-cell assassin: IAPP cytotoxicity. J Mol Endocrinol 2017; 59:R121-R140. [PMID: 28811318 DOI: 10.1530/jme-17-0105] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/15/2017] [Indexed: 12/28/2022]
Abstract
Islet amyloid polypeptide (IAPP) forms cytotoxic oligomers and amyloid fibrils in islets in type 2 diabetes (T2DM). The causal factors for amyloid formation are largely unknown. Mechanisms of molecular folding and assembly of human IAPP (hIAPP) into β-sheets, oligomers and fibrils have been assessed by detailed biophysical studies of hIAPP and non-fibrillogenic, rodent IAPP (rIAPP); cytotoxicity is associated with the early phases (oligomers/multimers) of fibrillogenesis. Interaction with synthetic membranes promotes β-sheet assembly possibly via a transient α-helical molecular conformation. Cellular hIAPP cytotoxicity can be activated from intracellular or extracellular sites. In transgenic rodents overexpressing hIAPP, intracellular pro-apoptotic signals can be generated at different points in β-cell protein synthesis. Increased cellular trafficking of proIAPP, failure of the unfolded protein response (UPR) or excess trafficking of misfolded peptide via the degradation pathways can induce apoptosis; these data indicate that defects in intracellular handling of hIAPP can induce cytotoxicity. However, there is no evidence for IAPP overexpression in T2DM. Extracellular amyloidosis is directly related to the degree of β-cell apoptosis in islets in T2DM. IAPP fragments, fibrils and multimers interact with membranes causing disruption in vivo and in vitro These findings support a role for extracellular IAPP in β-sheet conformation in cytotoxicity. Inhibitors of fibrillogenesis are useful tools to determine the aberrant mechanisms that result in hIAPP molecular refolding and islet amyloidosis. However, currently, their role as therapeutic agents remains uncertain.
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Affiliation(s)
- Daniel Raleigh
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
- Research Department of Structural and Molecule BiologyUniversity College London, London, UK
| | - Xiaoxue Zhang
- Department of ChemistryStony Brook University, Stony Brook, New York, USA
| | - Benoît Hastoy
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
| | - Anne Clark
- Oxford Centre for Diabetes Endocrinology and MetabolismUniversity of Oxford, Oxford, UK
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Guardado-Mendoza R, Chávez AO, Jiménez-Ceja LM, Hansis-Diarte A, DeFronzo RA, Folli F, Tripathy D. Islet amyloid polypeptide response to maximal hyperglycemia and arginine is altered in impaired glucose tolerance and type 2 diabetes mellitus. Acta Diabetol 2017; 54:53-61. [PMID: 27624579 DOI: 10.1007/s00592-016-0904-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 08/18/2016] [Indexed: 12/29/2022]
Abstract
AIMS Pancreatic islet amyloid deposition is a characteristic feature of type 2 diabetes mellitus (T2DM). Islet amyloid polypeptide (IAPP) is co-secreted with insulin, but its secretion profile and relationship to insulin and C-peptide in response to glucose and non-glucose stimuli has not been clearly defined. METHODS Forty subjects (13 NGT, 12 IGT and 15 T2DM) participated in an OGTT and two-step hyperglycemic (225 and 400 mg/dl) clamp (80 min/step) followed by an IV arginine bolus. Acute insulin (AIR), C-peptide (ACPR) and IAPP (AIAR) responses during each hyperglycemic step and following arginine (AIRArg) were assessed. RESULTS AIR and ACPR during both hyperglycemic steps and after arginine progressively decreased from NGT to IGT to T2DM. Fasting IAPP concentrations were higher in T2DM compared to NGT and IGT subjects. The acute IAPP0-10 was markedly decreased only in T2DM, while the acute IAPP80-90 response during the second step (80-160 min) of hyperglycemic clamp and in response to arginine was markedly impaired in both IGT and T2DM. The ratio of IAPP/C-peptide during the first (225 mg/dl) and second step (400 mg/dl), and in response to arginine, was decreased in T2DM versus both NGT and IGT (p < 0.01). The acute IAPP0-10 correlated with ACPR0-10 (r = 0.665, p < 0.001) and AIR0-10 (r = 0.543, p < 0.001). CONCLUSIONS Basal IAPP secretion is higher in T2DM and IGT versus NGT but is reduced in response to hyperglycemia and arginine. The IAPP/C-peptide ratio is reduced with prolonged and more severe hyperglycemia in T2DM individuals. CLINICAL TRIAL REGISTRATION NCT00845182.
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Affiliation(s)
- Rodolfo Guardado-Mendoza
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Division of Health Sciences, Department of Medicine and Nutrition, University of Guanajuato, Guanajuato, Mexico
- Departamento de Investigación, Hospital Regional de Alta Especialidad del Bajío, Guanajuato, Mexico
| | - Alberto O Chávez
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Lilia M Jiménez-Ceja
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Division of Health Sciences, Department of Medicine and Nutrition, University of Guanajuato, Guanajuato, Mexico
- Departamento de Investigación, Hospital Regional de Alta Especialidad del Bajío, Guanajuato, Mexico
| | - Andrea Hansis-Diarte
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Ralph A DeFronzo
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
- Audie L Murphy VA Hospital, South Texas Veteran Health Care System, San Antonio, TX, USA
| | - Franco Folli
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA
| | - Devjit Tripathy
- Diabetes Division, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, 78229, TX, USA.
- Audie L Murphy VA Hospital, South Texas Veteran Health Care System, San Antonio, TX, USA.
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Morita S, Ueyama M, Sakagashira S, Shimajiri Y, Yamana A, Furuta M, Sanke T. Protective role of human insulin against the cytotoxicity associated with human mutant S20G islet amyloid polypeptide. J Diabetes Investig 2013; 4:436-44. [PMID: 24843692 PMCID: PMC4025108 DOI: 10.1111/jdi.12069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/26/2013] [Accepted: 01/28/2013] [Indexed: 01/17/2023] Open
Abstract
Aims/Introduction Islet amyloid polypeptide (IAPP) is a main component of islet amyloid in type 2 diabetes and cosecreted from β‐cell with insulin. Clinical evidence from the patients with S20G mutation of the IAPP gene, as well as experimental evidence that insulin could inhibit amyloid formation of IAPP, suggests that a gradual reduction of insulin could be related to the cytotoxicity associated with S20G‐IAPP through long‐term deterioration of β‐cells in type 2 diabetes. Our objective was to show an effect of human insulin on S20G‐IAPP associated cytotoxicity. Materials and Methods We analyzed the cytotoxicity associated with S20G‐IAPP by controlling human insulin expression using adenovirus vectors with micro ribonucleic acid specifically against human insulin in endocrine AtT‐20ins cells, which express human insulin permanently. Additionally, we carried out a follow‐up study of circulating IAPP and insulin in type 2 diabetic patients. Results S20G‐IAPP expression was associated with a decrease in viability and an increase in terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate‐biotin nick end labeling‐positive cells in AtT‐20ins cells. Furthermore, downregulation of human insulin enhanced the cytotoxicity associated with S20G‐IAPP, and induced the cytotoxicity associated with wild‐type (WT)‐IAPP. Reduction of ubiquitin carboxy‐terminal hydrolase L1 activity enhanced cytotoxicity under the downregulation of human insulin expression in both S20G‐ and WT‐IAPP transduced cells. A 5‐year follow up of type 2 diabetic patients showed a disproportionate increase of serum fasting IAPP‐to‐insulin ratio from baseline. Conclusions Human insulin plays a protective role against the cytotoxicity associated with S20G‐IAPP, as well as WT‐IAPP. The findings could suggest long‐term deterioration of insulin secretion associates with IAPP linked cytotoxicity in type 2 diabetes.
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Affiliation(s)
- Shuhei Morita
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Minoru Ueyama
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Setsuya Sakagashira
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Yoshinori Shimajiri
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Akiko Yamana
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Machi Furuta
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama
| | - Tokio Sanke
- Department of Clinical Laboratory Medicine Wakayama Medical University Wakayama ; Diabetes Research Institute Fuchu Hospital Osaka Japan
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Despa F. Endoplasmic reticulum overcrowding as a mechanism of beta-cell dysfunction in diabetes. Biophys J 2010; 98:1641-8. [PMID: 20409485 DOI: 10.1016/j.bpj.2009.12.4295] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 09/24/2009] [Accepted: 12/14/2009] [Indexed: 01/25/2023] Open
Abstract
This study suggests a molecular mechanism that explains the accumulation of denaturated proinsulin in the endoplasmic reticulum (ER) of beta-cells. Such states were frequently observed in beta-cells experiencing increased demand for insulin production and were shown to lead to secretory dysfunction and diabetes. Here, a self-consistent kinetic model is used to investigate changes in protein translation due to ER overloading. The model is based on a molecular theory that relates the molecular composition and level of molecular crowding in the ER to the kinetic rates of protein folding/misfolding and transit to the Golgi apparatus (GA). This study suggests that molecular crowding forces can increase protein misfolding and impair the transport to the GA, thus overwhelming the quality control mechanism in the ER. A continual accumulation of toxic residues in the ER enhances even further the molecular crowding, accelerating protein denaturation. This article shows that molecular crowding affects differently the transit of various proteins through the ER. Apparently, the molecular crowding level that can inhibit the transport of native proinsulin to the GA influences to a lesser extent the transit of proamylin, a much smaller peptide cosynthesized with proinsulin in the ER. Smaller-volume misfolded proinsulin species may also win the passage competition through the ER and move on the secretory track. However, misfolded proinsulin fails the conversion to active insulin. This study can help us to decipher circumstances leading to the alteration of the secretory function in susceptible beta-cells and the onset of diabetes.
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Affiliation(s)
- F Despa
- Department of Pharmacology, University of California, Davis, California, USA.
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Esapa C, Moffitt JH, Novials A, McNamara CM, Levy JC, Laakso M, Gomis R, Clark A. Islet amyloid polypeptide gene promoter polymorphisms are not associated with Type 2 diabetes or with the severity of islet amyloidosis. Biochim Biophys Acta Mol Basis Dis 2005; 1740:74-8. [PMID: 15878744 DOI: 10.1016/j.bbadis.2005.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 01/10/2005] [Accepted: 02/01/2005] [Indexed: 11/26/2022]
Abstract
The over-expression of the islet amyloid polypeptide (IAPP) gene could be a causal factor for islet amyloidosis and beta-cell destruction in Type 2 diabetes (T2DM). An IAPP gene promoter polymorphism, IAPP-132G to A, has been associated with T2DM in Spain. To investigate this polymorphism in other cohorts and in relation to therapy, DNA from 425 T2DM and 279 unrelated, non-diabetic UK subjects (ND) and 102 T2DM and 80 ND Finnish subjects was examined. The relationship of amyloid severity (percent amyloid/islet) to prevalence (number of islets affected) and the association of IAPP-132G/A with amyloid was determined in post-mortem pancreas from 38 T2DM subjects. The -132G/A was not associated with T2DM in the UK cohorts (4.5% T2DM; 3.2% ND) or associated with requirement for insulin therapy by 6 years. The mutation was and undetected in the Finnish samples but a new variant, -166T/C, was identified in 2 Finnish T2DM subjects. -132G/A was found in 2/38 diabetic, amyloid-containing and 3/19 ND, amyloid-free subjects. The islet amyloid severity was linearly correlated with the prevalence in T2DM. The IAPP-132G/A promoter polymorphism is not associated with T2DM, a requirement for insulin therapy or with the degree of islet amyloidosis in cohorts from the UK or Finland.
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Affiliation(s)
- Christopher Esapa
- Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford, OX3 7LJ, UK
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Affiliation(s)
- Andrew Young
- Amylin Pharmaceuticals, Inc., San Diego, California, USA
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Jaikaran ET, Clark A. Islet amyloid and type 2 diabetes: from molecular misfolding to islet pathophysiology. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1537:179-203. [PMID: 11731221 DOI: 10.1016/s0925-4439(01)00078-3] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Islet amyloid polypeptide (IAPP, amylin) is secreted from pancreatic islet beta-cells and converted to amyloid deposits in type 2 diabetes. Conversion from soluble monomer, IAPP 1-37, to beta-sheet fibrils involves changes in the molecular conformation, cellular biochemistry and diabetes-related factors. In addition to the recognised amyloidogenic region, human IAPP (hIAPP) 20-29, the peptides human or rat IAPP 30-37 and 8-20, assume beta-conformation and form fibrils. These three amyloidogenic regions of hIAPP can be modelled as a folding intermediate with an intramolecular beta-sheet. A hypothesis is proposed for co-secretion of proIAPP with proinsulin in diabetes and formation of a 'nidus' adjacent to islet capillaries for subsequent accumulation of secreted IAPP to form the deposit. Although intracellular fibrils have been identified in experimental systems, extracellular deposition predominates in animal models and man. Extensive fibril accumulations replace islet cells. The molecular species of IAPP that is cytotoxic remains controversial. However, since fibrils form invaginations in cell membranes, small non-toxic IAPP fibrillar or amorphous accumulations could affect beta-cell stimulus-secretion coupling. The level of production of hIAPP is important but not a primary factor in islet amyloidosis; there is little evidence for inappropriate IAPP hypersecretion in type 2 diabetes and amyloid formation is generated in transgenic mice overexpressing the gene for human IAPP only against a background of obesity. Animal models of islet amyloidosis suggest that diabetes is induced by the deposits whereas in man, fibril formation appears to result from diabetes-associated islet dysfunction. Islet secretory failure results from progressive amyloidosis which provides a target for new therapeutic interventions.
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Affiliation(s)
- E T Jaikaran
- Diabetes Research Laboratories, Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Infirmary, Woodstock Road, Oxford, UK
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