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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 mid-lag phase species by five minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the middle of the lag phase of amyloid formation, after 5 min treatment with Proteinase K. Data show that h-IAPP lag phase intermediates are rapidly proteolytically degraded. The insert indicates the time point (green arrow, S3) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis. MALDI-TOF mass spectra of h-IAPP aliquots are shown in the following panels: (Figure 7—figure supplement 3–6) in the absence of proteinase K, Figure 7—figure supplement 7–10) after 5 min treatment with proteinase K and (Figure 7—figure supplement 11–14) after 40 min treatment with proteinase K. Data show that freshly dissolved h-IAPP at time-zero (red arrow) and h-IAPP lag phase intermediates (blue and green arrows) are rapidly proteolytically degraded, but h-IAPP amyloid fibrils are not (black arrow). The inserts in figure supplements 3-14 indicate the time point at which the aliquots were removed.DOI:http://dx.doi.org/10.7554/eLife.12977.034
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fig7s9: Characterization of h-IAPP mid-lag phase species by five minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the middle of the lag phase of amyloid formation, after 5 min treatment with Proteinase K. Data show that h-IAPP lag phase intermediates are rapidly proteolytically degraded. The insert indicates the time point (green arrow, S3) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis. MALDI-TOF mass spectra of h-IAPP aliquots are shown in the following panels: (Figure 7—figure supplement 3–6) in the absence of proteinase K, Figure 7—figure supplement 7–10) after 5 min treatment with proteinase K and (Figure 7—figure supplement 11–14) after 40 min treatment with proteinase K. Data show that freshly dissolved h-IAPP at time-zero (red arrow) and h-IAPP lag phase intermediates (blue and green arrows) are rapidly proteolytically degraded, but h-IAPP amyloid fibrils are not (black arrow). The inserts in figure supplements 3-14 indicate the time point at which the aliquots were removed.DOI:http://dx.doi.org/10.7554/eLife.12977.034


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 mid-lag phase species by five minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the middle of the lag phase of amyloid formation, after 5 min treatment with Proteinase K. Data show that h-IAPP lag phase intermediates are rapidly proteolytically degraded. The insert indicates the time point (green arrow, S3) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis. MALDI-TOF mass spectra of h-IAPP aliquots are shown in the following panels: (Figure 7—figure supplement 3–6) in the absence of proteinase K, Figure 7—figure supplement 7–10) after 5 min treatment with proteinase K and (Figure 7—figure supplement 11–14) after 40 min treatment with proteinase K. Data show that freshly dissolved h-IAPP at time-zero (red arrow) and h-IAPP lag phase intermediates (blue and green arrows) are rapidly proteolytically degraded, but h-IAPP amyloid fibrils are not (black arrow). The inserts in figure supplements 3-14 indicate the time point at which the aliquots were removed.DOI:http://dx.doi.org/10.7554/eLife.12977.034
© Copyright Policy
Related In: Results  -  Collection

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

fig7s9: Characterization of h-IAPP mid-lag phase species by five minute Proteinase K digestion as monitored by MALDI-TOF MS.MALDI-TOF mass spectra of h-IAPP aliquots taken in the middle of the lag phase of amyloid formation, after 5 min treatment with Proteinase K. Data show that h-IAPP lag phase intermediates are rapidly proteolytically degraded. The insert indicates the time point (green arrow, S3) at which the aliquots were removed for Proteinase K treatment, prior to mass spectroscopy analysis. MALDI-TOF mass spectra of h-IAPP aliquots are shown in the following panels: (Figure 7—figure supplement 3–6) in the absence of proteinase K, Figure 7—figure supplement 7–10) after 5 min treatment with proteinase K and (Figure 7—figure supplement 11–14) after 40 min treatment with proteinase K. Data show that freshly dissolved h-IAPP at time-zero (red arrow) and h-IAPP lag phase intermediates (blue and green arrows) are rapidly proteolytically degraded, but h-IAPP amyloid fibrils are not (black arrow). The inserts in figure supplements 3-14 indicate the time point at which the aliquots were removed.DOI:http://dx.doi.org/10.7554/eLife.12977.034
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