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Hogan MF, Meier DT, Zraika S, Templin AT, Mellati M, Hull RL, Leissring MA, Kahn SE. Inhibition of Insulin-Degrading Enzyme Does Not Increase Islet Amyloid Deposition in Vitro. Endocrinology 2016; 157:3462-8. [PMID: 27404391 PMCID: PMC5007890 DOI: 10.1210/en.2016-1410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Islet amyloid deposition in human type 2 diabetes results in β-cell loss. These amyloid deposits contain the unique amyloidogenic peptide human islet amyloid polypeptide (hIAPP), which is also a known substrate of the protease insulin-degrading enzyme (IDE). Whereas IDE inhibition has recently been demonstrated to improve glucose metabolism in mice, inhibiting it has also been shown to increase cell death when synthetic hIAPP is applied exogenously to a β-cell line. Thus, we wanted to determine whether a similar deleterious effect is observed when hIAPP is endogenously produced and secreted from islets. To address this issue, we cultured hIAPP transgenic mouse islets that have the propensity to form amyloid for 48 and 144 hours in 16.7 mM glucose in the presence and absence of the IDE inhibitor 1. At neither time interval did IDE inhibition increase amyloid formation or β-cell loss. Thus, the inhibition of IDE may represent an approach to improve glucose metabolism in human type 2 diabetes, without inducing amyloid deposition and its deleterious effects.
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Affiliation(s)
- Meghan F Hogan
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Daniel T Meier
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Sakeneh Zraika
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Andrew T Templin
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Mahnaz Mellati
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Rebecca L Hull
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Malcolm A Leissring
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
| | - Steven E Kahn
- Division of Metabolism, Endocrinology, and Nutrition (M.F.H., D.T.M., S.Z., A.T.T., M.M., R.L.H., S.E.K.), Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108; and Institute for Memory Impairments and Neurological Disorders (M.A.L.), University of California, Irvine, Irvine, California 92697
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Kim J, Cheon H, Jeong YT, Quan W, Kim KH, Cho JM, Lim YM, Oh SH, Jin SM, Kim JH, Lee MK, Kim S, Komatsu M, Kang SW, Lee MS. Amyloidogenic peptide oligomer accumulation in autophagy-deficient β cells induces diabetes. J Clin Invest 2014; 124:3311-24. [PMID: 25036705 DOI: 10.1172/jci69625] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 05/29/2014] [Indexed: 02/06/2023] Open
Abstract
Islet amyloid accumulation is a hallmark of human type 2 diabetes (T2D). In contrast to human islet amyloid polypeptide (hIAPP), murine islet amyloid polypeptide (mIAPP) does not exhibit amyloidogenic propensity. Because autophagy is important in the clearance of amyloid-like proteins, we studied transgenic mice with β cell-specific expression of hIAPP to evaluate the contribution of autophagy in T2D-associated accumulation of hIAPP. In mice with β cell-specific expression of hIAPP, a deficiency in autophagy resulted in development of overt diabetes, which was not observed in mice expressing hIAPP alone or lacking autophagy alone. Furthermore, lack of autophagy in hIAPP-expressing animals resulted in hIAPP oligomer and amyloid accumulation in pancreatic islets, leading to increased death and decreased mass of β cells. Expression of hIAPP in purified monkey islet cells or a murine β cell line resulted in pro-hIAPP dimer formation, while dimer formation was absent or reduced dramatically in cells expressing either nonamyloidogenic mIAPP or nonfibrillar mutant hIAPP. In autophagy-deficient cells, accumulation of pro-hIAPP dimers increased markedly, and pro-hIAPP trimers were detected in the detergent-insoluble fraction. Enhancement of autophagy improved the metabolic profile of hIAPP-expressing mice fed a high-fat diet. These results suggest that autophagy promotes clearance of amyloidogenic hIAPP, autophagy deficiency exacerbates pathogenesis of human T2D, and autophagy enhancers have therapeutic potential for islet amyloid accumulation-associated human T2D.
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Hiddinga HJ, Sakagashira S, Ishigame M, Madde P, Sanke T, Nanjo K, Kudva YC, Lee JJ, van Deursen J, Eberhardt NL. Expression of wild-type and mutant S20G hIAPP in physiologic knock-in mouse models fails to induce islet amyloid formation, but induces mild glucose intolerance. J Diabetes Investig 2014; 3:138-47. [PMID: 24843557 PMCID: PMC4020731 DOI: 10.1111/j.2040-1124.2011.00166.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aims/Introduction: Human islet polypeptide S20G mutation (hIAPPS20G) is associated with earlier onset type 2 diabetes and increased amyloidogenicity and cytotoxicity in vitro vs wild‐type hIAPP (hIAPPWT), suggesting that amyloidogenesis may be pathogenic for type 2 diabetes. We compared the contributions of hIAPPS20G and hIAPPWT toward intra islet amyloid formation and development of type 2 diabetes in a unique physiologic knock‐in mouse model. Materials and Methods: We replaced the mouse IAPP gene (M allele) with hIAPPWT (W allele) and hIAPPS20G (G allele) via homologous recombination and backbred transgenic mice against C57Bl/6 strain 5 generations to minimize genetic variation. Mice (3 month old) were maintained on control (CD) or high fat diet (HFD) for 15 months and studied at 3 month intervals by oral glucose tolerance testing (OGTT) and pancreas histology to assess glucose homeostastis, amyloidogeneisis, islet mass, β cell replication, and apoptosis. Results: IAPP blood levels were indistinguishable in all mice. WW and GW mice maintained on both diets lacked intraislet amyloid at all ages. On both diets relative to MM controls WW and GW mice exhibit glucose intolerance (P < 0.008) with no differences in insulin secretion. However, GW mice secreted significantly more insulin (P < 0.03 that WW mice on both diets throughout the study. By 12 months on the high fat diet all mice increased their β cell mass about 3‐fold and were indistinguishable. Conclusions: Physiologic expression of hIAPPWT and hIAPPS20G in C57Bl/6 mice produces mild glucose intolerance with inappropriately normal insulin secretion that is independent of intraislet amyloid formation. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00166.x, 2011)
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Affiliation(s)
| | | | - Masayuki Ishigame
- The First Department of Medicine, Wakayama University of Medical Science
| | | | - Tokio Sanke
- Department of Clinical Laboratory Medicine, Wakayama Medical University, Wakayama, Japan
| | - Kishio Nanjo
- The First Department of Medicine, Wakayama University of Medical Science
| | - Yogish C Kudva
- Department of Medicine/Divisions of Endocrinology ; Human Cellular Therapy Laboratory, Mayo Clinic Rochester, Rochester, MN
| | - James J Lee
- Department of Biochemistry/Molecular Biology, Mayo Clinic Scottsdale, Scottsdale, AZ, USA
| | | | - Norman L Eberhardt
- Department of Medicine/Divisions of Endocrinology ; Biochemistry/Molecular Biology
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Watve M, Bodas A, Diwekar M. Altered autonomic inputs as a cause of pancreatic β-cell amyloid. Med Hypotheses 2013; 82:49-53. [PMID: 24321738 DOI: 10.1016/j.mehy.2013.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/03/2013] [Indexed: 01/09/2023]
Abstract
A partial loss of β-cell mass and β-cell dysfunction in Type 2 Diabetes Mellitus (T2DM) is associated with amyloid deposition but whether it is causal or consequential is debated. Although the in vitro polymerization of amylin has been studied in detail, the exact trigger for the mechanism in vivo has not been identified. One suggestion is that an increased load on β-cells results in inefficient handling of proteins leading to misfolding and aggregation, but this hypothesis is faced with certain paradoxes. We suggest an alternative mechanism based on the assumption that polymerization is a spontaneous process. The concentration of the polypeptide in β-cell granules is shown to be sufficient to allow polymerization. However if the rate of turnover in normal cells is greater than the rate of polymerization, amyloid deposition will not be observed. If this is true, it follows that amyloid deposition could be a result of increased retention time of amylin in the β-cell granules. In T2D, the sympathetic inputs are known to increase which could result in suppression of the secretion process. The increase in the retention time due to this suppression can allow polymerization. In addition to this in a prediabetic state parasympathetic stimulation increases β-cell proliferation. This reduces the insulin demand per cell thereby increasing the mean retention time. Thus a combination of contrasting actions of sympathetic and parasympathetic systems could lead to increase in the amyloid deposition. We suggest testable predictions of the alternative hypotheses and the lines of research needed to test them.
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Affiliation(s)
- Milind Watve
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India.
| | - Arushi Bodas
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
| | - Manawa Diwekar
- Indian Institute of Science Education and Research, Dr. Homi Bhabha Road, Pashan, Pune 411008, India
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5
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Cooper GJS, Aitken JF, Zhang S. Is type 2 diabetes an amyloidosis and does it really matter (to patients)? Diabetologia 2010; 53:1011-6. [PMID: 20229094 DOI: 10.1007/s00125-010-1715-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Accepted: 02/10/2010] [Indexed: 12/17/2022]
Affiliation(s)
- G J S Cooper
- School of Biological Sciences, and Maurice Wilkins Centre of Excellence for Molecular Biodiscovery, Faculty of Science, University of Auckland, Auckland, New Zealand.
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Masiello P. Animal models of type 2 diabetes with reduced pancreatic beta-cell mass. Int J Biochem Cell Biol 2005; 38:873-93. [PMID: 16253543 DOI: 10.1016/j.biocel.2005.09.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2005] [Revised: 09/02/2005] [Accepted: 09/08/2005] [Indexed: 12/31/2022]
Abstract
Type 2 diabetes is increasingly viewed as a disease of insulin deficiency due not only to intrinsic pancreatic beta-cell dysfunction but also to reduction of beta-cell mass. It is likely that, in diabetes-prone subjects, the regulated beta-cell turnover that adapts cell mass to body's insulin requirements is impaired, presumably on a genetic basis. We still have a limited knowledge of how and when this derangement occurs and what might be the most effective therapeutic strategy to preserve beta-cell mass. The animal models of type 2 diabetes with reduced beta-cell mass described in this review can be extremely helpful (a) to have insight into the mechanisms underlying the defective growth or accelerated loss of beta-cells leading to the beta-cell mass reduction; (b) to investigate in prospective studies the mechanisms of compensatory adaptation and subsequent failure of a reduced beta-cell mass. Furthermore, these models are of invaluable importance to test the effectiveness of potential therapeutic agents that either stimulate beta-cell growth or inhibit beta-cell death.
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Affiliation(s)
- Pellegrino Masiello
- Dipartimento di Patologia Sperimentale, Biotecnologie Mediche, Infettivologia ed Epidemiologia, University of Pisa, Scuola Medica, Italy.
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7
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Andrikopoulos S, Hull RL, Verchere CB, Wang F, Wilbur SM, Wight TN, Marzban L, Kahn SE. Extended life span is associated with insulin resistance in a transgenic mouse model of insulinoma secreting human islet amyloid polypeptide. Am J Physiol Endocrinol Metab 2004; 286:E418-24. [PMID: 14613923 DOI: 10.1152/ajpendo.00137.2003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pancreatic amyloid is found in patients with insulinomas and type 2 diabetes. To study mechanisms of islet amyloidogenesis, we produced transgenic mice expressing the unique component of human islet amyloid, human islet amyloid polypeptide (hIAPP). These mice develop islet amyloid after 12 mo of high-fat feeding. To determine whether we could accelerate the rate of islet amyloid formation, we crossbred our hIAPP transgenic animals with RIP-Tag mice that develop islet tumors and die at 12 wk of age from hypoglycemia. At 12 wk of age, this new line of hIAPPxRIP-Tag mice was heavier (29.7 +/- 1.0 vs. 25.0 +/- 1.3 g, P < 0.05) and had increased plasma glucose levels (4.6 +/- 0.4 vs. 2.9 +/- 0.6 mmol/l, P < 0.05) compared with littermate RIP-Tag mice. However, the hIAPPxRIP-Tag mice did not display islet amyloid or amyloid fibrils despite high circulating hIAPP levels (24.6 +/- 7.0 pmol/l). Interestingly, hIAPPxRIP-Tag mice had a longer life span than RIP-Tag mice (121 +/- 8 vs. 102 +/- 5 days, P < 0.05). This increase in life span in hIAPPxRIP-Tag was positively correlated with body weight (r = 0.48, P < 0.05) and was associated with decreased insulin sensitivity compared with RIP-Tag mice. hIAPPxRIP-Tag mice did not develop amyloid during their 4-mo life span, suggesting that increased hIAPP secretion is insufficient for islet amyloid formation within such a short time. However, hIAPPxRIP-Tag mice did have an increase in life span that was associated with insulin resistance, suggesting that hIAPP has extrapancreatic effects, possibly on peripheral glucose metabolism.
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Affiliation(s)
- Sofianos Andrikopoulos
- Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington, USA
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8
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Cooper GJS. Amylin and Related Proteins: Physiology and Pathophysiology. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Wang F, Hull RL, Vidal J, Cnop M, Kahn SE. Islet amyloid develops diffusely throughout the pancreas before becoming severe and replacing endocrine cells. Diabetes 2001; 50:2514-20. [PMID: 11679429 DOI: 10.2337/diabetes.50.11.2514] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Islet amyloid occurs in >90% of type 2 diabetic patients and may play a role in the pathogenesis of this disease. To determine whether islet amyloid occurs diffusely throughout the pancreas, whether it affects islets equally, and whether it decreases islet endocrine cells, we characterized islet amyloidosis by computerized fluorescence microscopy in transgenic mice that develop typical islet amyloid. These mice produce the unique amyloidogenic component of human islet amyloid, human islet amyloid polypeptide (hIAPP). The prevalence of amyloid (number of islets containing amyloid/total number of islets x 100) and the severity of amyloid (Sigmaamyloid area/Sigmaislet area x 100) were found to be uniform throughout the pancreas. Furthermore, a high prevalence of amyloid was observed in islets when the severity of amyloid was only 1.5% of the islet area, suggesting a diffuse distribution of amyloid from the very early stages of islet amyloidosis. In 12 hIAPP transgenic mice with an amyloid severity of 9.6 +/- 3.4%, the proportion of islets composed of beta- and delta-cells was reduced in the transgenic mice compared with 6 nontransgenic mice that do not develop amyloid (beta-cells: 62.9 +/- 3.1% vs. 75.5 +/- 0.9%, P = 0.02; delta-cells: 2.8 +/- 0.5% vs. 4.4 +/- 0.4%, P = 0.05), whereas the proportion of islets composed of alpha-cells did not significantly differ between the two groups of mice. In the individual islets in these transgenic mice, amyloid severity was inversely correlated with beta-cell, (r = -0.59, P < 0.0001), alpha-cell (r = -0.32, P < 0.0001), and delta-cell (r = -0.25, P < 0.0001) areas. In conclusion, islet amyloidosis occurs uniformly throughout the pancreas, affecting all islets before becoming severe. A reduction in islet endocrine mass starts at this early stage of islet amyloid development and progresses as amyloid mass increases.
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Affiliation(s)
- F Wang
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, Veterans Affairs Puget Sound Health Care System and University of Washington, Seattle, Washington 98108, USA
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Hiddinga HJ, Eberhardt NL. Intracellular amyloidogenesis by human islet amyloid polypeptide induces apoptosis in COS-1 cells. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:1077-88. [PMID: 10233846 PMCID: PMC1866559 DOI: 10.1016/s0002-9440(10)65360-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Human islet amyloid polypeptide (hIAPP) is co-secreted with insulin from pancreatic islet beta cells. This peptide spontaneously aggregates in the form of fibrils, and amyloid deposits are associated with dead or degenerating beta cells, a hallmark of noninsulin-dependent diabetes mellitus. We demonstrated that COS-1 cells transfected with vectors expressing hIAPP exhibited intracellular amyloid deposits that were associated with cell death (O'Brien, Butler, Kreutter, Kane, Eberhardt, Am J Pathol 1995, 147:609-616). To establish the mechanism of cell death, we transfected COS-1 cells with vectors expressing amyloidogenic hIAPP or nonamyloidogenic rat IAPP and mutant hIAPP constructs and assayed them for markers characteristic of apoptosis and necrosis by fluorescence-activated cell sorting analysis. Amyloidogenic hIAPP-transfected COS cells contained up to threefold more apoptotic cells present at 96 hours after transfection compared with the nonamyloidogenic vector controls. The hIAPP-induced apoptosis was negligible at 24 and 48 hours after transfection and was maximal at 96 hours which parallels the time course of amyloidogenesis. Immunohistochemical staining and confocal microscopy showed that hIAPP is localized with distinct clustering in the endoplasmic reticulum and Golgi apparatus with no discernable extracellular staining. These experiments provide direct evidence that intracellular hIAPP amyloid causes cell death by triggering apoptotic pathways.
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Affiliation(s)
- H J Hiddinga
- Division of Endocrinology, Departments of Medicine and Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905, USA
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Benthem L, Taborsky GJ. Hyperglycemia suppresses the sympatho-adrenal response to hypoxia, but not to handling stress. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1998; 73:149-55. [PMID: 9862390 DOI: 10.1016/s0165-1838(98)00133-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We hypothesized that the ability of prior hyperglycemia to suppress the sympatho-adrenal response would depend on the type of stress. To test this hypothesis, hyperglycemia was induced in chronically catheterized rats, before submitting them to either hypoxia (7.5% O2) or handling stress. Central venous blood samples were drawn for the determination of plasma glucose, epinephrine (EPI), norepinephrine (NOR) and insulin concentrations. Hypoxia caused significant increases in plasma EPI and NOR concentrations (deltaEPI = + 2.95+/-0.68 nmol/l, deltaNOR = + 12.45+/-1.29 nmol/l). Hyperglycemia, antecedent to hypoxia, dose dependently reduced the sympatho-adrenal response. In contrast, the sympatho-adrenal response to handling stress was not affected by even marked antecedent hyperglycemia (deltaEPI = + 2.48+/-0.46 nmol/l, deltaNOR = + 3.12+/-0.69 nmol/l at glucose = 20.7+/-0.6 mmol/l; vs. deltaEPI = + 2.48 + 0.58 nmol/l, deltaNOR= +2.97+/-0.11 nmol/l at glucose = 6.77+/-0.17 mg/dl). Thus, antecedent hyperglycemia suppresses the hypoxia-induced activation of both the sympathetic nerves and the adrenal medulla, but not the activation induced by handling. We conclude that the ability of hyperglycemia to suppress sympathetic activation depends on the stress producing the activation. We therefore speculate that hypoxic stress has a metabolic component to its central activation that handling stress does not.
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Affiliation(s)
- L Benthem
- Division of Endocrinology and Metabolism, Veterans Affairs Medical Center, Seattle, WA 98108, USA.
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12
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van Rossum D, Hanisch UK, Quirion R. Neuroanatomical localization, pharmacological characterization and functions of CGRP, related peptides and their receptors. Neurosci Biobehav Rev 1997; 21:649-78. [PMID: 9353797 DOI: 10.1016/s0149-7634(96)00023-1] [Citation(s) in RCA: 385] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Calcitonin generelated peptide (CGRP) is a neuropeptide discovered by a molecular approach over 10 years ago. More recently, islet amyloid polypeptide or amylin, and adrenomedullin were isolated from human insulinoma and pheochromocytoma respectively, and revealed between 25 and 50% sequence homology with CGRP. This review discusses findings on the anatomical distributions of CGRP mRNA, CGRP-like immunoreactivity and receptors in the central nervous system, as well as the potential physiological roles for CGRP. The anatomical distribution and biological activities of amylin and adrenomedullin are also presented. Based upon the differential biological activity of various CGRP analogs, the CGRP receptors have been classified in two major classes, namely the CGRP1 and CGRP2 subtypes. A third subtype has also been proposed (e.g. in the nucleus accumbens) as it does not share the pharmacological properties of the other two classes. The anatomical distribution and the pharmacological characteristics of amylin binding sites in the rat brain are different from those reported for CGRP but share several similarities with the salmon calcitonin receptors. The receptors identified thus far for CGRP and related peptides belong to the G protein-coupled receptor superfamily. Indeed, modulation of adenylate cyclase activity following receptor activation has been reported for CGRP, amylin and adrenomedullin. Furthermore, the binding affinity of CGRP and related peptides is modulated by nucleotides such as GTP. The cloning of various calcitonin and most recently of CGRP1 and adrenomedullin receptors was reported and revealed structural similarities but also significant differences to other members of the G protein-coupled receptors. They may thus form a new subfamily. The cloning of the amylin receptor(s) as well as of the other putative CGRP receptor subtype(s) are still awaited. Finally, a broad variety of biological activities has been described for CGRP-like peptides. These include vasodilation, nociception, glucose uptake and the stimulation of glycolysis in skeletal muscles. These effects may thus suggest their potential role and therapeutic applications in migraine, subarachnoid haemorrhage, diabetes and pain-related mechanisms, among other disorders.
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Affiliation(s)
- D van Rossum
- Department of Pharmacology, McGill University, Douglas Hospital Research Centre, Verdun, Québec, Canada
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Tokuyama T, Yagui K, Yamaguchi T, Huang CI, Kuramoto N, Shimada F, Miyazaki J, Horie H, Saito Y, Makino H, Kanatsuka A. Expression of human islet amyloid polypeptide/amylin impairs insulin secretion in mouse pancreatic beta cells. Metabolism 1997; 46:1044-51. [PMID: 9284894 DOI: 10.1016/s0026-0495(97)90276-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Non-insulin-dependent diabetes mellitus (NIDDM) is associated histopathologically with islet amyloid deposits of which a major component is islet amyloid polypeptide (IAPP)/amylin. We examined whether endogenous IAPP controls insulin secretion via a local effect within pancreatic islets and whether overexpression of this peptide contributes to pancreatic beta-cell dysfunction in this disease. Transgenic mice expressing human IAPP in pancreatic beta cell were used in this study. Human IAPP expression did not influence the mouse proinsulin mRNA level and insulin content. Glucose-induced insulin secretion was decreased in the isolated pancreatic islets of transgenic mice. MIN6, a glucose-responsive pancreatic beta-cell line, was transfected with human IAPP cDNA by a lipofectin method. Human IAPP expression was confirmed by RNA blot and immunohistochemical analysis. In two transfectants expressing the largest amount of human IAPP, insulin secretion was increased in response to glucose stimulation; however, the magnitude of the insulin response in cells transfected with human IAPP was smaller than in control clones. Insulin content was not influenced by the expression. We conclude that endogenous IAPP inhibits insulin secretion via an autocrine effect within pancreatic islets, and that the impaired insulin secretion in this disease may be partly caused by overexpression of IAPP.
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Affiliation(s)
- T Tokuyama
- Department of Internal Medicine II, Chiba University School of Medicine, Japan
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Patti ME, Kahn CR. Lessons from transgenic and knockout animals about noninsulin-dependent diabetes mellitus. Trends Endocrinol Metab 1996; 7:311-9. [PMID: 18406764 DOI: 10.1016/s1043-2760(96)00154-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The application of transgenic techniques to alter gene expression in vivo has provided new models to evaluate the role of specific genes in the complex pathogenesis of noninsulin-dependent diabetes mellitus (NIDDM). In this review, we summarize methods used to create transgenic animals and highlight results from those models which have contributed to our understanding of the overall pathophysiology of NIDDM. Transgenic animal models have clearly demonstrated the requirement for normal insulin action in skeletal muscle, adipose tissue, and liver, as well as normal insulin secretion by the pancreatic beta-cell, in the maintenance of glucose homeostasis. In addition, these data confirm that isolated defects in single critical genes, including the insulin receptor, IRS-1, and glucokinase, may play a role in the development of some types of insulin resistance and NIDDM. However, it is likely that multiple additive defects, both genetic and acquired, are required to produce the full clinical syndrome typical of more common forms of NIDDM.
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Affiliation(s)
- M E Patti
- Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
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Verchere CB, D'Alessio DA, Palmiter RD, Weir GC, Bonner-Weir S, Baskin DG, Kahn SE. Islet amyloid formation associated with hyperglycemia in transgenic mice with pancreatic beta cell expression of human islet amyloid polypeptide. Proc Natl Acad Sci U S A 1996; 93:3492-6. [PMID: 8622964 PMCID: PMC39637 DOI: 10.1073/pnas.93.8.3492] [Citation(s) in RCA: 201] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Pancreatic islet amyloid deposits are a characteristic pathologic feature of non-insulin-dependent diabetes mellitus and contain islet amyloid polypeptide (IAPP; amylin). We used transgenic mice that express human IAPP in pancreatic beta cells to explore the potential role of islet amyloid in the pathogenesis of non-insulin-dependent diabetes mellitus. Extensive amyloid deposits were observed in the pancreatic islets of approximately 80% of male transgenic mice > 13 months of age. Islet amyloid deposits were rarely observed in female transgenic mice (11%) and were never seen in nontransgenic animals. Ultrastructural analysis revealed that these deposits were composed of human IAPP-immunoreactive fibrils that accumulated between beta cells and islet capillaries. Strikingly, approximately half of the mice with islet amyloid deposits were hyperglycemic (plasma glucose > 11 mM). In younger (6- to 9-month-old) male transgenic mice, islet amyloid deposits were less commonly observed but were always associated with severe hyperglycemia (plasma glucose > 22 mM). These data indicate that expression of human IAPP in beta cells predisposes male mice to the development of islet amyloid and hyperglycemia. The frequent concordance of islet amyloid with hyperglycemia in these mice suggests an interdependence of these two conditions and supports the hypothesis that islet amyloid may play a role in the development of hyperglycemia.
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Affiliation(s)
- C B Verchere
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, Howard Hughes Medical Institute, University of Washington, Seattle 98195, USA
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Silvestre RA, Salas M, Rodríguez-Gallardo J, García-Hermida O, Fontela T, Marco J. Effect of (8-32) salmon calcitonin, an amylin antagonist, on insulin, glucagon and somatostatin release: study in the perfused pancreas of the rat. Br J Pharmacol 1996; 117:347-50. [PMID: 8789389 PMCID: PMC1909271 DOI: 10.1111/j.1476-5381.1996.tb15197.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. The 8-32 fragment of salmon calcitonin ((8-32) sCT) has been proposed as a highly selective amylin receptor antagonist. 2. In the present study, we have studied the influence of (8-32) sCT on the inhibitory effect of both amylin and its structural congener, calcitonin gene-related peptide (CGRP), on insulin secretion in the rat perfused pancreas. 3. Both amylin and CGRP, at 75 pM, clearly inhibited glucose-induced insulin release (by 80% and by 70%, respectively). Simultaneous infusion of 10 microM (8-32) sCT reversed the inhibitory effect of amylin (by 80%; P < 0.05 vs. amylin experiments) but did not significantly affect the inhibition of glucose-induced insulin output elicited by CGRP. Furthermore, at the same concentration (10 microM), (8-32) sCT alone potentiated the insulin response to 7 mM glucose (2.5 fold; P < 0.05) whilst it did not affect glucagon or somatostatin secretion. 4. The observation that infusion of an amylin antagonist into the rat pancreas potentiates the insulin response to glucose, favours the concept of endogenous amylin as an inhibitor of insulin release. 5. Finally, as an amylin antagonist at the level of the beta-cell, (8-32) sCT might be considered of potential interest in experimental and clinical pharmacology.
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Affiliation(s)
- R A Silvestre
- Department of Physiology, Universidad Autónoma de Madrid, Spain
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Westermark G, Arora MB, Fox N, Carroll R, Chan SJ, Westermark P, Steiner DF. Amyloid Formation in Response to β Cell Stress Occurs In Vitro, but Not In Vivo, in Islets of Transgenic Mice Expressing Human Islet Amyloid Polypeptide. Mol Med 1995. [DOI: 10.1007/bf03401591] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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Mulder H, Ahrén B, Stridsberg M, Sundler F. Non-parallelism of islet amyloid polypeptide (amylin) and insulin gene expression in rats islets following dexamethasone treatment. Diabetologia 1995; 38:395-402. [PMID: 7796979 DOI: 10.1007/bf00410276] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Islet amyloid polypeptide (IAPP), a novel islet hormone candidate, has been reported to be over-expressed relative to insulin in rats following dexamethasone treatment. In order to investigate the expression of IAPP and insulin following dexamethasone treatment of rats for 12 days, we applied in situ hybridization and immunocytochemistry, allowing us to evaluate islet changes in gene expression and morphology. Tissue concentrations of IAPP and insulin were measured by radioimmunoassay. A low dose of dexamethasone (0.2 mg/kg daily) increased the islet levels of IAPP and insulin mRNA to 249 +/- 13% and 150 +/- 24% of controls, respectively (p < 0.001 and p < 0.01). A high dose of dexamethasone (2.0 mg/kg daily) increased the islet levels of IAPP and insulin mRNA to 490 +/- 13% and 203 +/- 9% of controls, respectively (p < 0.001 and p < 0.001). The pancreatic concentration of IAPP increased more than that of insulin (p < 0.05). Morphometric analysis revealed that dexamethasone treatment induced both hyperplasia and hypertrophy of insulin cells. Changes in the cellular localization of IAPP and insulin mRNA were not observed. Thus, we conclude that the increased level of IAPP mRNA is due to both an increase at the cellular level as well as hyperplasia/hypertrophy of insulin cells. In contrast, the increased level of insulin mRNA appears to be due to hyperplasia/hypertrophy of insulin cells, since insulin gene expression decreased at the cellular level (p < 0.001 vs controls). These observations provide further evidence that IAPP and insulin gene expression are regulated in a non-parallel fashion, which may be relevant to the pathogenesis of non-insulin-dependent diabetes mellitus.
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Affiliation(s)
- H Mulder
- Department of Medical Cell Research, University of Lund, Sweden
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