Insulin as an amyloid-fibril protein at sites of repeated insulin injections in a diabetic patient

Dische, F. E.; Wernstedt, Christer; Westermark, Gunilla T.; Westermark, Per; Pepys, Mark B.; Rennie, John; Gilbey, S. G.; Watkins, P J

doi:10.1007/bf00276849

Cited by 288 publications

(219 citation statements)

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“…Insulin fibrils pose a variety of problems in biomedical and biotechnological applications. Amyloid deposits of insulin have been observed in patients with diabetes after repeated injection and in normal aging, as well as after subcutaneous insulin infusion (16,17).In our previous work we have shown the important role of partially folded intermediates in insulin fibrillation in vitro (13, 18 -20). In fact, our studies showed that insulin, which is a hexamer at physiological pH, undergoes rapid fibrillation starting at relatively low concentrations of guanidine hydrochloride and urea.…”

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confidence: 94%

Early Events in the Fibrillation of Monomeric Insulin

Ahmad

Uversky

Hong

et al. 2005

Journal of Biological Chemistry

245

247

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Insulin has a largely ␣-helical structure and exists as a mixture of hexameric, dimeric, and monomeric states in solution, depending on the conditions: the protein is monomeric in 20% acetic acid. Insulin forms amyloid-like fibrils under a variety of conditions, especially at low pH. In this study we investigated the fibrillation of monomeric human insulin by monitoring changes in CD, attenuated total reflectance-Fourier transform infrared spectroscopy, 8-anilinonaphthalenesulfonic acid fluorescence, thioflavin T fluorescence, dynamic light scattering, and H/D exchange during the initial stages of the fibrillation process to provide insight into early events involving the monomer. The results demonstrate the existence of structural changes occurring before the onset of fibril formation, which are detectable by multiple probes. The data indicate at least two major populations of oligomeric intermediates between the native monomer and fibrils. Both have significantly non-native conformations, and indicate that fibrillation occurs from a betarich structure significantly distinct from the native fold.A number of human diseases are caused by the pathogenic deposition of proteins in the form of amyloid-like fibrils (1-7). Several non-pathogenic proteins and peptides also undergo amyloid like fibril formation on destabilization of their native state (7-10). The fact that structurally and sequentially non-homologous proteins are able to self-assemble into fibrils possessing similar morphology (e.g. 10 -18 nm width, birefringence to polarized light, and cross-␤ structure) suggests a common molecular mechanism in the fibrillation pathways. A variety of hypotheses for the mechanism of fibril formation have been proposed.Insulin is a 51-residue hormone with a largely ␣-helical structure. It exists as a mixture of hexameric, dimeric, and monomeric states in solution, with the relative population of different oligomeric species being strongly dependent on the environmental conditions: the protein is predominantly monomeric in 20% acetic acid, dimeric in 20 mM HCl, and hexameric at pH 7.5 in the presence of zinc. Insulin forms amyloidlike fibrils under a variety of conditions (11-13), with various overall morphologies depending on the arrangement of constituent protofilaments (14, 15). Insulin fibrils pose a variety of problems in biomedical and biotechnological applications. Amyloid deposits of insulin have been observed in patients with diabetes after repeated injection and in normal aging, as well as after subcutaneous insulin infusion (16,17).In our previous work we have shown the important role of partially folded intermediates in insulin fibrillation in vitro (13, 18 -20). In fact, our studies showed that insulin, which is a hexamer at physiological pH, undergoes rapid fibrillation starting at relatively low concentrations of guanidine hydrochloride and urea. The predominant species characterized by various biophysical techniques under these conditions was shown to be a partially folded, expanded monomer, which is presen...

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confidence: 94%

Early Events in the Fibrillation of Monomeric Insulin

Ahmad

Uversky

Hong

et al. 2005

Journal of Biological Chemistry

245

247

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“…It has been suggested, however, that its specificity is based on recognition of specific secondary structures rather than specific peptide bonds [16]. It is interesting to note that although the IDE substrates, insulin, atria1 natriuretic peptide and glucagon, are greatly different in primary structure, they probably share a common structural motif allowing them to form amyloid fibrils under certain conditions in vitro [ 171 and in vivo [18,19] been shown to be organized in a cross-j? conformation [ 171.…”

Section: Introdwtionmentioning

confidence: 99%

Alzheimer's β‐amyloid peptide specifically interacts with and is degraded by insulin degrading enzyme

1994

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Cerebral deposition of B-amyloid peptide @A) is a hallmark of Alzheimer's disease. Concentration of /IA could play a critical role in the rate of amyloid deposition. It is therefore of considerable importance to identify proteases involved in processing ofpA. '251-labeled synthetic /IA specifically cross-linked to a single protein with M, = 110,000 in cytosol fractions from rat brain and liver. This protein was identified as insulin degrading enzyme (IDE) since the labeling of the 110 kDa protein was completely blocked by an excess of insulin, and anti-IDE monoclonal antibodies precipitated the labeled protein. Purified rat IDE effectively degraded /IA.Key wor& Alzheirner's disease; p-Amyloid;Insulin degrading enzyme; Oxidative modification; Protein degradation; Brain; Rat IntrodwtionAlzheimer's disease amyloid is composed of a 39-43 residue /I-amyloid protein (BA) [l-3] that is derived from a set of larger transmembrane precursor proteins @4PPs) [4,5]. G rowing evidence is accumulating that processing of jL4PP may occur intracellularly [6-81 and that /IA is a normal product of cell metabolism [9-l 11. A recent finding that cultured human neurons generate /IA intracellularly before it is released into the medium [12] suggests the possibility that PA accumulation in Alzheimer's brain could result from defects in intracellular proteolytic machinery responsible for its breakdown. Thus, protease involved in processing ofBA is a potential target for pharmacological treatment of the disease.We considered that among intracellular proteases which could participate in degradation of PA, the insulin degrading enzyme (IDE; EC 3.4.22.11) is a very likely candidate. IDE is a highly selective protease involved in the breakdown of certain peptide hormones [ 13-151. IDE does not have a strict specificity for any amino acid residue [16]. It has been suggested, however, that its specificity is based on recognition of specific secondary structures rather than specific peptide bonds [16]. It is interesting to note that although the IDE substrates, insulin, atria1 natriuretic peptide and glucagon, are greatly different in primary structure, they probably share a common structural motif allowing them to form amyloid fibrils under certain conditions in vitro [ 171 and in vivo [18,19]. In amyloid fibrils, different proteins have been shown to be organized in a cross-j? conformation [ 171. Therefore, IDE specificity could be based on recognition of/3-structures either present on the surface of the substrate molecules or adopted upon binding to the protease. This possibility suggests that IDE might also degrade PA.Here we show that PA is a substrate for rat liver IDE. Furthermore, we demonstrate that IDE is the only protein that can be specifically cross-linked to PA in crude extracts of rat brain and liver, suggesting for a role for IDE in the cellular processing of /3A. Materials and methods MaterialsThe following materials were obtained: ['2SI]insulin (1.2 kCiimmo1) from Dainabott (Tokyo, Japan), /JA,,, and PAi, from Bachem ...

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“…In the late 1960's, the characteristic 4.8 Å cross-␤ x-ray fiber diffraction of pathological amyloid was recognized (4,16), and the cross-␤ structure of insulin fibrils was reported by Burke and Rougvie in 1972 (21). Amyloid deposits containing intact insulin molecules, including the disulfide bridges, have been reported in a patient with insulin-dependent diabetes undergoing treatment by injection of porcine insulin (22). At pH 2, mass spectrometry and hydrogen exchange measurements reveal that insulin forms soluble assemblies of up to 12 molecules in equilibrium with monomers and smaller oligomers (23,24).…”

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confidence: 99%

The protofilament structure of insulin amyloid fibrils

Jiménez

Nettleton

Bouchard

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

779

822

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Under solution conditions where the native state is destabilized, the largely helical polypeptide hormone insulin readily aggregates to form amyloid fibrils with a characteristic cross-␤ structure. However, there is a lack of information relating the 4.8 Å ␤-strand repeat to the higher order assembly of amyloid fibrils. We have used cryo-electron microscopy (EM), combining single particle analysis and helical reconstruction, to characterize these fibrils and to study the three-dimensional (3D) arrangement of their component protofilaments. Low-resolution 3D structures of fibrils containing 2, 4, and 6 protofilaments reveal a characteristic, compact shape of the insulin protofilament. Considerations of protofilament packing indicate that the cross-␤ ribbon is composed of relatively flat ␤-sheets rather than being the highly twisted, ␤-coil structure previously suggested by analysis of globular protein folds. Comparison of the various fibril structures suggests that very small, local changes in ␤-sheet twist are important in establishing the long-range coiling of the protofilaments into fibrils of diverse morphology.U nder conditions that destabilize the native state, proteins can self-aggregate into insoluble, fibrillar assemblies (1-3). In the form of amyloid fibrils or fibril precursors, the proteins not only lack their original biological function but also may be harmful to organisms, causing pathologies such as Alzheimer's and prion diseases. Although amyloid precursor proteins do not share any sequence or structural homology, amyloid fibrils are typically unbranched, protease-resistant filaments approximately 100 Å in diameter and composed of Ϸ20-35 Å wide protofilaments, which are sometimes arranged around an electron lucent core (4, 5). Recently, several nonpathological proteins and short peptides have been shown to self-assemble into amyloid-like fibrils (6-9), leading to the suggestion that amyloid formation is a generic property of polypeptide chains (3, 10).The overall morphology of amyloid aggregates depends on the conditions in which fibrillogenesis takes place, and different fibril morphologies are often observed in the same preparation (7,(11)(12)(13)(14). Variable structures also are seen in ex vivo fibrils extracted from amyloidotic tissue (4, 15). The morphological variation seems to be caused by fibrils with a variable number and arrangement of protofilaments. X-ray fiber diffraction studies reveal a characteristic cross-␤ structure with ␤-strands of the precursor protein arranged perpendicular to, and ribbon-like ␤-sheets parallel to, the fibril axis (2, 16, 17). The ␤-strand repeat has also been directly visualized by cryo-EM (8). However, there is a lack of three-dimensional (3D) structural information on how the 4.8 Å ␤-strand repeat relates to the overall fibril assembly.The polypeptide hormone insulin has a mainly helical native structure, with its two polypeptide chains linked by two interchain and one intra-chain disulfide bonds (18). In vitro, insulin is readily converted to an inactiv...

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Insulin as an amyloid-fibril protein at sites of repeated insulin injections in a diabetic patient

Cited by 288 publications

References 12 publications

Early Events in the Fibrillation of Monomeric Insulin

Early Events in the Fibrillation of Monomeric Insulin

Alzheimer's β‐amyloid peptide specifically interacts with and is degraded by insulin degrading enzyme

The protofilament structure of insulin amyloid fibrils

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