Structural Basis for the Inhibition of Truncated Islet Amyloid Polypeptide Aggregation by Cu(II): Insights into the Bioinorganic Chemistry of Type II Diabetes

2015 ◽  
Vol 54 (8) ◽  
pp. 3788-3796 ◽  
Author(s):  
Lina Rivillas-Acevedo ◽  
Carolina Sánchez-López ◽  
Carlos Amero ◽  
Liliana Quintanar
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Olapeju Bolarinwa ◽  
Chunpu Li ◽  
Nawal Khadka ◽  
Qi Li ◽  
Yan Wang ◽  
...  

AbstractThe abnormal folding and aggregation of functional proteins into amyloid is a typical feature of many age-related diseases, including Type II diabetes. Growing evidence has revealed that the prevention of aggregate formation in culprit proteins could retard the progression of amyloid diseases. Human Amylin, also known as human islet amyloid polypeptide (hIAPP), is the major factor for categorizing Type II diabetes as an amyloid disease. Specifically, hIAPP has a great aggregation potential, which always results in a lethal situation for the pancreas. Many peptide inhibitors have been constructed from the various segments of the full-length hIAPP peptide; however, only a few have their origin from the screening of combinatorial peptidomimetic library. In this study, based on HW-155, which was previously discovered from a one–bead–one compound (OBOC) library to inhibit Aβ40 aggregation, we investigated eight (8) analogues and evaluated their amyloid-prevention capabilities for inhibiting fibrillization of hIAPP. Characterization studies revealed that all analogues of HW-155, as well as HW-155, were effective inhibitors of the fibril formation by hIAPP.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Phuong Trang Nguyen ◽  
Nagore Andraka ◽  
Carole Anne De Carufel ◽  
Steve Bourgault

Type II diabetes mellitus is associated with the deposition of fibrillar aggregates in pancreatic islets. The major protein component of islet amyloids is the glucomodulatory hormone islet amyloid polypeptide (IAPP). Islet amyloid fibrils are virtually always associated with several biomolecules, including apolipoprotein E, metals, glycosaminoglycans, and various lipids. IAPP amyloidogenesis has been originally perceived as a self-assembly homogeneous process in which the inherent aggregation propensity of the peptide and its local concentration constitute the major driving forces to fibrillization. However, over the last two decades, numerous studies have shown a prominent role of amyloid cofactors in IAPP fibrillogenesis associated with the etiology of type II diabetes. It is increasingly evident that the biochemical microenvironment in which IAPP amyloid formation occurs and the interactions of the polypeptide with various biomolecules not only modulate the rate and extent of aggregation, but could also remodel the amyloidogenesis process as well as the structure, toxicity, and stability of the resulting fibrils.


1991 ◽  
Vol 124 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Haruhiko Ohsawa ◽  
Azuma Kanatsuka ◽  
Yoshiharu Tokuyama ◽  
Takahide Yamaguchi ◽  
Hideichi Makino ◽  
...  

Abstract. Amyloid deposits in somatostatinomas are rare observations. To examine the characteristics of this amyloid, we compared amyloid deposits in a somatostatinoma to those found in pancreatic tissue in patients with Type II diabetes mellitus and in insulinomas, using immunohistochemical techniques and specific antibodies to islet amyloid polypeptide or other pancreatic hormones, as well as electron-microscopy. Antibodies to islet amyloid polypeptide regions 8-17 or 25-37 were confirmed to be specific. Amyloid deposits in patients with Type II diabetes mellitus and in insulinomas, but not those in the somatostatinoma strongly reacted with these antibodies, or to an antibody to amyloid P component. Amyloid deposits in the somatostatinoma were not reactive with antibodies to somatostatin or to other pancreatic hormones. Electron-microscopic examinations revealed that amyloid fibrils in the somatostatinoma were thinner and more randomly distributed than were those in islets from patients with Type II diabetes mellitus. As amyloid in somatostatinomas is unlike that consisting of islet amyloid polypeptide or other mature pancreatic hormones, it may be a novel type of local amyloid in pancreatic islets.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Zhi-Xue Xu ◽  
Qiang Zhang ◽  
Gong-Li Ma ◽  
Cong-Heng Chen ◽  
Yan-Ming He ◽  
...  

The abnormal fibrillation of human islet amyloid polypeptide (hIAPP) has been implicated in the development of type II diabetes. Aluminum is known to trigger the structural transformation of many amyloid proteins and induce the formation of toxic aggregate species. The (−)-epigallocatechin gallate (EGCG) is considered capable of binding both metal ions and amyloid proteins with inhibitory effect on the fibrillation of amyloid proteins. However, the effect of Al(III)/EGCG complex on hIAPP fibrillation is unclear. In the present work, we sought to view insight into the structures and properties of Al(III) and EGCG complex by using spectroscopic experiments and quantum chemical calculations and also investigated the influence of Al(III) and EGCG on hIAPP fibrillation and aggregation as well as their combined interference on this process. Our studies demonstrated that Al(III) could promote fibrillation and aggregation of hIAPP, while EGCG could inhibit the fibrillation of hIAPP and lead to the formation of hIAPP amorphous aggregates instead of the ordered fibrils. Furthermore, we proved that the Al(III)/EGCG complex in molar ratio of 1 : 1 as Al(EGCG)(H2O)2 could inhibit the hIAPP fibrillation more effectively than EGCG alone. The results provide the invaluable reference for the new drug development to treat type II diabetes.


2012 ◽  
Vol 102 (5) ◽  
pp. 1059-1068 ◽  
Author(s):  
Chang-Chun Lee ◽  
Yen Sun ◽  
Huey W. Huang

RSC Advances ◽  
2017 ◽  
Vol 7 (69) ◽  
pp. 43491-43501 ◽  
Author(s):  
Jingjing Guo ◽  
Wanqi Sun ◽  
Li Li ◽  
Fufeng Liu ◽  
Wenyu Lu

Inhibitory effect of brazilin on the fibrillogenesis of hIAPP was explored using biochemical, biophysical, cytobiological and molecular simulation experiments. Brazilin was a potential compound for therapeutic treatment of type II diabetes mellitus.


2021 ◽  
Vol 121 (3) ◽  
pp. 1845-1893
Author(s):  
Danilo Milardi ◽  
Ehud Gazit ◽  
Sheena E. Radford ◽  
Yong Xu ◽  
Rodrigo U. Gallardo ◽  
...  

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