S20G Mutant Amylin Exhibits Increased in Vitro Amyloidogenicity and Increased Intracellular Cytotoxicity Compared to Wild-Type Amylin

Sakagashira, Setsuya; Hiddinga, Henry J.; Tateishi, Kensuke; Sanke, Tokio; Hanabusa, Tadashi; Nanjo, Kishio; Eberhardt, Norman L.

doi:10.1016/s0002-9440(10)64848-1

Cited by 125 publications

(144 citation statements)

References 33 publications

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“…S3 and Table S1), which agreed with the previous reports [16,17]. It is of interest to note that spectra showed modest differences in the region of 210-230 nm between the hIAPP and pIAPP fragments, where spectra of hIAPP (20)(21)(22)(23)(24)(25)(26)(27)(28)(29) and hIAPP (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) showed more positive CD signals than those of pIAPP (20)(21)(22)(23)(24)(25)(26)(27)(28)(29) and pIAPP (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29) (Fig. 2A...…”

Section: Secondary Structures Determination By Far-uv CD and Spectra supporting

confidence: 89%

“…All decapeptides (IAPP (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)) and tridecapeptides (IAPP (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)) were manually synthesized using standard 9-fluorenylmethyl chloroformate-based solid-phase peptide synthesis (SPPS) methodology as we previously described [8]. Crude peptides were purified by reverse phase high performance liquid chromatography using C4 semi-preparative or analytical column (Kromasil, AkzoNobel, Netherlands), and their identities were confirmed by ESI-MS.…”

Section: Peptide Synthesis and Purificationmentioning

confidence: 99%

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Porcine islet amyloid polypeptide fragments are refractory to amyloid formation

et al. 2010

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a b s t r a c tOf 10 variation sites between sequences of amyloid-resistant porcine islet amyloid polypeptide (pIAPP) and amyloid-prone human IAPP (hIAPP), seven locate within residues 17-29, the most amyloidogenic fragment within hIAPP. To investigate how these variations affect amyloidogenicity, 26 IAPP(17-29) or IAPP(20-29) variants were synthesized and their secondary structures, amyloidogenicity, oligomerization and cytotoxicity were studied. Our results indicated that pIAPP fragments are refractory to amyloid formation and significantly less cytotoxic compared with hIAPP fragments. A novel stable dimer was observed in pIAPP(20-29) solution, whereas hIAPP(20-29) exists mostly as monomers and trimers. Among all human to porcine substitutions, S20R caused the most prolonged lag time and significantly attenuated cytotoxicity. The different oligomerization and amyloidogenic properties of hIAPP and pIAPP fragments are discussed.

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Section: Secondary Structures Determination By Far-uv CD and Spectra supporting

confidence: 89%

Section: Peptide Synthesis and Purificationmentioning

confidence: 99%

Porcine islet amyloid polypeptide fragments are refractory to amyloid formation

et al. 2010

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“…9 The mutant polypeptide aggregates faster 10,11 and is more toxic than wildtype IAPP. 10 Together, these findings suggest that molecules that significantly delay or completely inhibit IAPP self-assembly are attractive therapeutics for T2D.The self-assembly of monomeric proteins to fibrils may be mediated by nucleation. 12 The overall process is described in quantitative terms by a nucleation period (t NP ) during which the nucleus, composed of polypeptide chains arranged in a manner that resembles the aggregated conformation, 12 is formed and by a maximal rate of self-assembly (k max ) at which the protein is converted to fibrils.…”

mentioning

confidence: 89%

“…3 A missense mutation involving the substitution of serine at position 20 with glycine ( Figure 1A) has been linked to an early onset, more severe form of T2D. 9 The mutant polypeptide aggregates faster 10,11 and is more toxic than wildtype IAPP. 10 Together, these findings suggest that molecules that significantly delay or completely inhibit IAPP self-assembly are attractive therapeutics for T2D.…”

mentioning

confidence: 99%

Kinetic Profile of Amyloid Formation in the Presence of an Aromatic Inhibitor by Nuclear Magnetic Resonance

Liu

Gaines

Robbins

et al. 2012

ACS Med. Chem. Lett.

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The self-assembly of amyloid proteins into β-sheet rich assemblies is associated with human amyloidoses including Alzheimer's disease, Parkinson's disease, and type 2 diabetes. An attractive therapeutic strategy therefore is to develop small molecules that would inhibit protein self-assembly. Natural polyphenols are potential inhibitors of β-sheet formation. How these compounds affect the kinetics of self-assembly studied by thioflavin T (ThT) fluorescence is not understood primarily because their presence interferes with ThT fluorescence. Here, we show that by plotting peak intensities from nuclear magnetic resonance (NMR) against incubation time, kinetic profiles in the presence of the polyphenol can be obtained from which kinetic parameters of self-assembly can be easily determined. In applying this technique to the selfassembly of the islet amyloid polypeptide in the presence of curcumin, a biphenolic compound found in turmeric, we show that the kinetic profile is atypical in that it shows a prenucleation period during which there is no observable decrease in NMR peak intensities. KEYWORDS: amyloid, ThT fluorescence, curcumin, NMR A total of 27 proteins have been identified to form the extracellular β-sheet containing amyloid fibrils associated with human amyloidoses. 1 These include the amyloid-β protein (Aβ) in Alzheimer's disease, α-synuclein in Parkinson's disease, and the islet amyloid polypeptide (IAPP) in type 2 diabetes (T2D). In spite of the large differences in the primary structure of the precursor proteins, the mature fibrils possess common characteristics including unbranched, 10 nm wide morphology as determined by electron microscopy, the ability to bind Congo red and exhibit green birefringence, and X-ray diffraction patterns consistent with cross-β-sheet. 1 Mechanistic studies of fibril formation in hydro have shown that Aβ, α-synuclein, and IAPP undergo a random coil to β-sheet conformational transition. 2 IAPP is a 37-residue polypeptide ( Figure 1A) that is cosecreted with insulin by β-cells of the islets of Langerhans in the pancreas. Molecular biological, biophysical, and genetic evidence support a central role for IAPP in β-cell death and dysfunction associated with T2D. 3,4 The progressive formation of islet amyloid leads to a decrease in β-cell mass. 5 The toxicity of fibrillar IAPP was first demonstrated in the early 1990s, 6 but more recent studies suggest that oligomeric assemblies could be the proximate cytotoxic species in T2D. 3,7 A number of mechanisms behind the toxicity of IAPP oligomers have been proposed, 8 but recent biophysical studies have focused on the ability of IAPP to disrupt model membranes, as reviewed recently. 3 A missense mutation involving the substitution of serine at position 20 with glycine ( Figure 1A) has been linked to an early onset, more severe form of T2D. 9 The mutant polypeptide aggregates faster 10,11 and is more toxic than wildtype IAPP. 10 Together, these findings suggest that molecules that significantly delay or completely inhibit IAP...

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“…The S20G mutation is associated with only moderate alterations in insulin secretion in the small number of patients examined so far and, therefore, its role in T2DM is unclear [67]. However, synthetic S20G hIAPP forms amyloid more readily than wild-type IAPP [68] and it exerts greater biological cytotoxicity [69] indicating that small changes in structure can affect the refolding process. A mutation in the IAPP gene promoter has been identified and associated with T2DM in a Spanish population [70] which suggests that regulation of gene expression could be important.…”

Section: Genetically Determined Structural Changesmutations In the Iamentioning

confidence: 99%

Islet amyloid: a complication of islet dysfunction or an aetiological factor in Type 2 diabetes?

2004

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The role of islet amyloidosis in the onset and progression of Type 2 diabetes remains obscure. Islet amyloid polypeptide is a 37 amino-acid, beta-cell peptide which is co-stored and co-released with insulin. Human islet amyloid polypeptide refolds to a β-conformation and oligomerises to form insoluble fibrils; proline substitutions in rodent islet amyloid polypeptide prevent this molecular transition. Pro-islet amyloid polypeptide (67 amino acids in man) is processed in secretory granules. Refolding of islet amyloid polypeptide may be prevented by intragranular heterodimer formation with insulin (but not proinsulin). Diabetes-associated abnormal proinsulin processing could contribute to de-stabilisation of granular islet amyloid polypeptide. Increased pro-islet amyloid polypeptide secretion as a consequence of islet dysfunction could promote fibrillogenesis; the propeptide forms fibrils and binds to basement membrane glycosamino-glycans. Islet amyloid polypeptide gene polymorphisms are not universally associated with Type 2 diabetes. Transgenic mice expressing human islet amyloid polypeptide gene have increased islet amyloid polypeptide concentrations but develop islet amyloid only against a background of obesity and/or high fat diet. In transgenic mice, obese monkeys and cats, initially small perivascular deposits progressively increase to occupy 80% islet mass; the severity of amyloidosis in animal models is related to the onset of hyperglycaemia, suggesting that islet amyloid and the associated destruction of islet cells cause diabetes. In human diabetes, islet amyloid can affect less than 1% or up to 80% of islets indicating that islet amyloidosis largely results from diabetes-related pathologies and is not an aetiological factor for hyperglycaemia. However, the associated progressive betacell destruction leads to severe islet dysfunction and insulin requirement. [Diabetologia (2004) 47:157-169]

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S20G Mutant Amylin Exhibits Increased in Vitro Amyloidogenicity and Increased Intracellular Cytotoxicity Compared to Wild-Type Amylin

Cited by 125 publications

References 33 publications

Porcine islet amyloid polypeptide fragments are refractory to amyloid formation

Porcine islet amyloid polypeptide fragments are refractory to amyloid formation

Kinetic Profile of Amyloid Formation in the Presence of an Aromatic Inhibitor by Nuclear Magnetic Resonance

Islet amyloid: a complication of islet dysfunction or an aetiological factor in Type 2 diabetes?

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