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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

Characterization of h-IAPP amyloid fibrils by forty minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the saturation phase of amyloid formation, after 40 min treatment with Proteinase K. Data show the expected molecular weight for h-IAPP (3903 Daltons), indicating that the amyloid fibrils are not proteolytically degraded, even after longer incubation with the enzyme. The insert indicates the time point (black arrow, S4) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis.DOI:http://dx.doi.org/10.7554/eLife.12977.039
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fig7s14: Characterization of h-IAPP amyloid fibrils by forty minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the saturation phase of amyloid formation, after 40 min treatment with Proteinase K. Data show the expected molecular weight for h-IAPP (3903 Daltons), indicating that the amyloid fibrils are not proteolytically degraded, even after longer incubation with the enzyme. The insert indicates the time point (black arrow, S4) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis.DOI:http://dx.doi.org/10.7554/eLife.12977.039

Mentions: (A) Structural model of an ANS molecule. (B) ANS fluorescence emission spectra of h-IAPP at time-zero (black, ····), lag phase intermediates (blue, —) and amyloid fibrils (red, - - - -). (C) Kinetic assays monitored by ANS binding (●) and thioflavin-T binding (▲) confirm that h-IAPP lag phase intermediates do not bind ANS. Figure 7—figure supplements 1–14 provide additional dye-binding studies using bis-ANS and Nile Red, and biophysical characterization of the toxic h-IAPP lag phase intermediates.


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)

Characterization of h-IAPP amyloid fibrils by forty minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the saturation phase of amyloid formation, after 40 min treatment with Proteinase K. Data show the expected molecular weight for h-IAPP (3903 Daltons), indicating that the amyloid fibrils are not proteolytically degraded, even after longer incubation with the enzyme. The insert indicates the time point (black arrow, S4) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis.DOI:http://dx.doi.org/10.7554/eLife.12977.039
© Copyright Policy
Related In: Results  -  Collection

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

fig7s14: Characterization of h-IAPP amyloid fibrils by forty minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the saturation phase of amyloid formation, after 40 min treatment with Proteinase K. Data show the expected molecular weight for h-IAPP (3903 Daltons), indicating that the amyloid fibrils are not proteolytically degraded, even after longer incubation with the enzyme. The insert indicates the time point (black arrow, S4) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis.DOI:http://dx.doi.org/10.7554/eLife.12977.039
Mentions: (A) Structural model of an ANS molecule. (B) ANS fluorescence emission spectra of h-IAPP at time-zero (black, ····), lag phase intermediates (blue, —) and amyloid fibrils (red, - - - -). (C) Kinetic assays monitored by ANS binding (●) and thioflavin-T binding (▲) confirm that h-IAPP lag phase intermediates do not bind ANS. Figure 7—figure supplements 1–14 provide additional dye-binding studies using bis-ANS and Nile Red, and biophysical characterization of the toxic h-IAPP lag phase intermediates.

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