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Time-resolved studies define the nature of toxic IAPP intermediates, providing insight for anti-amyloidosis therapeutics.

Abedini A, Plesner A, Cao P, Ridgway Z, Zhang J, Tu LH, Middleton CT, Chao B, Sartori DJ, Meng F, Wang H, Wong AG, Zanni MT, Verchere CB, Raleigh DP, Schmidt AM - Elife (2016)

Bottom Line: These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species.They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure.Aromatic interactions modulate, but are not required for toxicity.

View Article: PubMed Central - PubMed

Affiliation: Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States.

ABSTRACT
Islet amyloidosis by IAPP contributes to pancreatic β-cell death in diabetes, but the nature of toxic IAPP species remains elusive. Using concurrent time-resolved biophysical and biological measurements, we define the toxic species produced during IAPP amyloid formation and link their properties to induction of rat INS-1 β-cell and murine islet toxicity. These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species. They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure. Aromatic interactions modulate, but are not required for toxicity. Not all IAPP oligomers are toxic; toxicity depends on their partially structured conformational states. Some anti-amyloid agents paradoxically prolong cytotoxicity by prolonging the lifetime of the toxic species. The data highlight the distinguishing properties of toxic IAPP oligomers and the common features that they share with toxic species reported for other amyloidogenic polypeptides, providing information for rational drug design to treat IAPP induced β-cell death.

No MeSH data available.


Related in: MedlinePlus

Fluorescence detected thioflavin-T binding assay (black) showing the kinetics of amyloid formation by a solution of h-IAPP used in the proteolytic digestion studies presented in Figure 7—figure supplements 3–14. Arrows indicate time points at which aliquots were removed and subjected to Proteinase K treatment. The time points are denoted as: (red, S1) time-zero, (blue, S2) early lag phase intermediates, (green, S3) mid-lag phase intermediates and (black, S4) saturation phase containing amyloid fibrils.DOI:http://dx.doi.org/10.7554/eLife.12977.027
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fig7s2: Fluorescence detected thioflavin-T binding assay (black) showing the kinetics of amyloid formation by a solution of h-IAPP used in the proteolytic digestion studies presented in Figure 7—figure supplements 3–14. Arrows indicate time points at which aliquots were removed and subjected to Proteinase K treatment. The time points are denoted as: (red, S1) time-zero, (blue, S2) early lag phase intermediates, (green, S3) mid-lag phase intermediates and (black, S4) saturation phase containing amyloid fibrils.DOI:http://dx.doi.org/10.7554/eLife.12977.027

Mentions: We examined the susceptibility of the oligomeric lag phase intermediates to proteolytic digestion by Proteinase K in order to further probe their structure and flexibility. h-IAPP monomers and lag phase intermediates are rapidly digested by the protease, while h-IAPP amyloid fibrils are not, even after 40 min of incubation (Figure 7—figure supplement 2–14). The results indicate that the intermediates are much less structured than the amyloid fibrils, and show that h-IAPP amyloid fibrils have similar anti-protease properties as amyloid fibrils derived from other proteins.


Time-resolved studies define the nature of toxic IAPP intermediates, providing insight for anti-amyloidosis therapeutics.

Abedini A, Plesner A, Cao P, Ridgway Z, Zhang J, Tu LH, Middleton CT, Chao B, Sartori DJ, Meng F, Wang H, Wong AG, Zanni MT, Verchere CB, Raleigh DP, Schmidt AM - Elife (2016)

Fluorescence detected thioflavin-T binding assay (black) showing the kinetics of amyloid formation by a solution of h-IAPP used in the proteolytic digestion studies presented in Figure 7—figure supplements 3–14. Arrows indicate time points at which aliquots were removed and subjected to Proteinase K treatment. The time points are denoted as: (red, S1) time-zero, (blue, S2) early lag phase intermediates, (green, S3) mid-lag phase intermediates and (black, S4) saturation phase containing amyloid fibrils.DOI:http://dx.doi.org/10.7554/eLife.12977.027
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940161&req=5

fig7s2: Fluorescence detected thioflavin-T binding assay (black) showing the kinetics of amyloid formation by a solution of h-IAPP used in the proteolytic digestion studies presented in Figure 7—figure supplements 3–14. Arrows indicate time points at which aliquots were removed and subjected to Proteinase K treatment. The time points are denoted as: (red, S1) time-zero, (blue, S2) early lag phase intermediates, (green, S3) mid-lag phase intermediates and (black, S4) saturation phase containing amyloid fibrils.DOI:http://dx.doi.org/10.7554/eLife.12977.027
Mentions: We examined the susceptibility of the oligomeric lag phase intermediates to proteolytic digestion by Proteinase K in order to further probe their structure and flexibility. h-IAPP monomers and lag phase intermediates are rapidly digested by the protease, while h-IAPP amyloid fibrils are not, even after 40 min of incubation (Figure 7—figure supplement 2–14). The results indicate that the intermediates are much less structured than the amyloid fibrils, and show that h-IAPP amyloid fibrils have similar anti-protease properties as amyloid fibrils derived from other proteins.

Bottom Line: These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species.They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure.Aromatic interactions modulate, but are not required for toxicity.

View Article: PubMed Central - PubMed

Affiliation: Diabetes Research Program, Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, New York University School of Medicine, New York, United States.

ABSTRACT
Islet amyloidosis by IAPP contributes to pancreatic β-cell death in diabetes, but the nature of toxic IAPP species remains elusive. Using concurrent time-resolved biophysical and biological measurements, we define the toxic species produced during IAPP amyloid formation and link their properties to induction of rat INS-1 β-cell and murine islet toxicity. These globally flexible, low order oligomers upregulate pro-inflammatory markers and induce reactive oxygen species. They do not bind 1-anilnonaphthalene-8-sulphonic acid and lack extensive β-sheet structure. Aromatic interactions modulate, but are not required for toxicity. Not all IAPP oligomers are toxic; toxicity depends on their partially structured conformational states. Some anti-amyloid agents paradoxically prolong cytotoxicity by prolonging the lifetime of the toxic species. The data highlight the distinguishing properties of toxic IAPP oligomers and the common features that they share with toxic species reported for other amyloidogenic polypeptides, providing information for rational drug design to treat IAPP induced β-cell death.

No MeSH data available.


Related in: MedlinePlus