The aggregation of the 37-amino acid polypeptide human islet amyloid polypeptide (hIAPP), as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of human pancreatic β-islet cells in type 2 diabetes. hIAPP is considered to be one of the most amyloidogenic proteins known. The quick aggregation of hIAPP leads to the formation of toxic species, such as oligomers and fibers, that damage mammalian cells (both human and rat pancreatic cells). Whether this toxicity is necessary for the progression of type 2 diabetes or merely a side effect of the disease remains unclear. If hIAPP aggregation into toxic amyloid is on-path for developing type 2 diabetes in humans, islet amyloid polypeptide (IAPP) aggregation would likely need to play a similar role within other organisms known to develop the disease. In this work, we compared the aggregation potential and cellular toxicity of full-length IAPP from several diabetic and nondiabetic organisms whose aggregation propensities had not yet been determined for full-length IAPP.

The aggregation of the 37‐amino acid polypeptide human Islet Amyloid Polypeptide (hIAPP, amylin), as either insoluble amyloid or as small oligomers, appears to play a direct role in the death of pancreatic β‐islet cells in type 2 diabetes. It is known that several organisms express non‐amyloidogenic variants of IAPP (such as rat and mouse) and are not known to develop diabetes naturally. Conversely, several organisms express highly amyloidogenic variants of IAPP (such as human, cat and primates) and are known to develop diabetes. Despite the significant amount of genetic information available, no comprehensive study has been conducted to directly correlate IAPP aggregation potential to the propensity to develop diabetes within the animal kingdom. In this work, we will compare the aggregation potential of naturally occurring IAPP variants from organisms known to, or known not to, develop diabetes. IAPP peptide variants were chemically synthesized. Each variant was tested for its amyloid aggregation potential using Circular Dichroism and Atomic Force Microscopy.Support or Funding InformationNational Institute of Health (Grant#: 1R15DK112172)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.