Impaired Processing of Human Pro-Islet Amyloid Polypeptide Is Not a Causative Factor for Fibril Formation or Membrane Damage in Vitro

Biochemistry ◽  
2009 ◽  
Vol 48 (46) ◽  
pp. 10918-10925 ◽  
Author(s):  
Lucie Khemtémourian ◽  
Gemma Lahoz Casarramona ◽  
Dennis P. L. Suylen ◽  
Tilman M. Hackeng ◽  
Johannes D. Meeldijk ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Causative Factor ◽  
Fibril Formation ◽  
Islet Amyloid

scholarly journals Pancreatic beta-cell granule peptides form heteromolecular complexes which inhibit islet amyloid polypeptide fibril formation

2004 ◽  
Vol 377 (3) ◽  
pp. 709-716 ◽  
Author(s):  
Emma T. A. S. JAIKARAN ◽  
Melanie R. NILSSON ◽  
Anne CLARK
Keyword(s):  
Type 2 Diabetes ◽  
Amyloid Fibrils ◽  
Secretory Granules ◽  
Pancreatic Beta Cell ◽  
Islet Amyloid Polypeptide ◽  
Fibril Formation ◽  
Islet Amyloid ◽  
Β Sheet

Islet amyloid polypeptide (IAPP), or ‘amylin’, is co-stored with insulin in secretory granules of pancreatic islet β-cells. In Type 2 diabetes, IAPP converts into a β-sheet conformation and oligomerizes to form amyloid fibrils and islet deposits. Granule components, including insulin, inhibit spontaneous IAPP fibril formation in vitro. To determine the mechanism of this inhibition, molecular interactions of insulin with human IAPP (hIAPP), rat IAPP (rIAPP) and other peptides were examined using surface plasmon resonance (BIAcore), CD and transmission electron microscopy (EM). hIAPP and rIAPP complexed with insulin, and this reaction was concentration-dependent. rIAPP and insulin, but not pro-insulin, bound to hIAPP. Insulin with a truncated B-chain, to prevent dimerization, also bound hIAPP. In the presence of insulin, hIAPP did not spontaneously develop β-sheet secondary structure or form fibrils. Insulin interacted with pre-formed IAPP fibrils in a regular repeating pattern, as demonstrated by immunoEM, suggesting that the binding sites for insulin remain exposed in hIAPP fibrils. Since rIAPP and hIAPP form complexes with insulin (and each other), this could explain the lack of amyloid fibrils in transgenic mice expressing hIAPP. It is likely that IAPP fibrillogenesis is inhibited in secretory granules (where the hIAPP concentration is in the millimolar range) by heteromolecular complex formation with insulin. Alterations in the proportions of insulin and IAPP in granules could disrupt the stability of the peptide. The increase in the proportion of unprocessed pro-insulin produced in Type 2 diabetes could be a major factor in destabilization of hIAPP and induction of fibril formation.

scholarly journals BRICHOS domain of Bri2 inhibits islet amyloid polypeptide (IAPP) fibril formation and toxicity in human beta cells

2018 ◽  
Vol 115 (12) ◽  
pp. E2752-E2761 ◽  
Author(s):  
Marie E. Oskarsson ◽  
Erik Hermansson ◽  
Ye Wang ◽  
Nils Welsh ◽  
Jenny Presto ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Beta Cells ◽  
Transmembrane Protein ◽  
Islet Amyloid Polypeptide ◽  
Fibril Formation ◽  
Islet Amyloid ◽  
Peripheral Tissues ◽  
Beta Cell Line

Aggregation of islet amyloid polypeptide (IAPP) into amyloid fibrils in islets of Langerhans is associated with type 2 diabetes, and formation of toxic IAPP species is believed to contribute to the loss of insulin-producing beta cells. The BRICHOS domain of integral membrane protein 2B (Bri2), a transmembrane protein expressed in several peripheral tissues and in the brain, has recently been shown to prevent fibril formation and toxicity of Aβ42, an amyloid-forming peptide in Alzheimer disease. In this study, we demonstrate expression of Bri2 in human islets and in the human beta-cell line EndoC-βH1. Bri2 colocalizes with IAPP intracellularly and is present in amyloid deposits in patients with type 2 diabetes. The BRICHOS domain of Bri2 effectively inhibits fibril formation in vitro and instead redirects IAPP into formation of amorphous aggregates. Reduction of endogenous Bri2 in EndoC-βH1 cells with siRNA increases sensitivity to metabolic stress leading to cell death while a concomitant overexpression of Bri2 BRICHOS is protective. Also, coexpression of IAPP and Bri2 BRICHOS in lateral ventral neurons of Drosophila melanogaster results in an increased cell survival. IAPP is considered to be the most amyloidogenic peptide known, and described findings identify Bri2, or in particular its BRICHOS domain, as an important potential endogenous inhibitor of IAPP aggregation and toxicity, with the potential to be a possible target for the treatment of type 2 diabetes.

scholarly journals The flanking peptides issue from the maturation of the human islet amyloid polypeptide (hIAPP) slightly modulate hIAPP-fibril formation but not hIAPP-induced cell death

Biochimie ◽  
2020 ◽  
Vol 170 ◽  
pp. 26-35 ◽  
Author(s):  
Shadai Salazar Vazquez ◽  
Bertrand Blondeau ◽  
Pierre Cattan ◽  
Mathieu Armanet ◽  
Ghislaine Guillemain ◽  
...  
Keyword(s):  
Cell Death ◽  
Islet Amyloid Polypeptide ◽  
Fibril Formation ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide

scholarly journals Regulation of divalent metal ions to the aggregation and membrane damage of human islet amyloid polypeptide oligomers

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12815-12825
Author(s):  
Yajie Wang ◽  
Feihong Meng ◽  
Tong Lu ◽  
Chunyun Wang ◽  
Fei Li
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Divalent Metal ◽  
Human Islet ◽  
Divalent Metal Ions ◽  
Islet Amyloid ◽  
Induced Membrane ◽  
Human Islet Amyloid Polypeptide

Their is a counteraction between a decrease in the disruptive ability of metal-associated oligomer species and an increase in the quantity of oligomers promoted by the metal binding in the activity of hIAPP induced membrane damage.

scholarly journals Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

2010 ◽  
Vol 10 ◽  
pp. 879-893 ◽  
Author(s):  
Nathaniel G. N. Milton ◽  
J. Robin Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Islet Amyloid Polypeptide ◽  
Amyloid Β ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide ◽  
Transmission Electron

The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrilsin vitroandin vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KDof 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

Modeling the Interface between Islet Amyloid Polypeptide and Insulin-Based Aggregation Inhibitors: Correlation to Aggregation Kinetics and Membrane Damage

2012 ◽  
Vol 52 (5) ◽  
pp. 1298-1307 ◽  
Author(s):  
Hector Figueroa ◽  
Durgaprasad Peddi ◽  
Joshua M. Osborne ◽  
Brenan M. Wilson ◽  
Ranadheer Reddy Pesaru ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Aggregation Kinetics ◽  
Islet Amyloid ◽  
Aggregation Inhibitors

Ruthenium complexes as novel inhibitors of human islet amyloid polypeptide fibril formation

Metallomics ◽  
2013 ◽  
Vol 5 (12) ◽  
pp. 1599 ◽  
Author(s):  
Lei He ◽  
Xuesong Wang ◽  
Cong Zhao ◽  
Hongfei Wang ◽  
Weihong Du
Keyword(s):  
Islet Amyloid Polypeptide ◽  
Ruthenium Complexes ◽  
Fibril Formation ◽  
Human Islet ◽  
Islet Amyloid ◽  
Human Islet Amyloid Polypeptide
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