Fas-Associated Death Receptor Signaling Evoked by Human Amylin in Islet β-Cells
Fas-Associated Death Receptor Signaling Evoked by Human Amylin in Islet β-Cells Shaoping Zhang 1 2 , Hong Liu 1 , Hua Yu 1 and Garth J.S. Cooper 1 2 3 1 School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand 2 Maurice Wilkins Centre for Molecular BioDiscover...
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Published in | Diabetes (New York, N.Y.) Vol. 57; no. 2; pp. 348 - 356 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
Alexandria, VA
American Diabetes Association
01.02.2008
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Subjects | |
Online Access | Get full text |
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Summary: | Fas-Associated Death Receptor Signaling Evoked by Human Amylin in Islet β-Cells
Shaoping Zhang 1 2 ,
Hong Liu 1 ,
Hua Yu 1 and
Garth J.S. Cooper 1 2 3
1 School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
2 Maurice Wilkins Centre for Molecular BioDiscovery, University of Auckland, Auckland, New Zealand
3 Medical Research Council Immunochemistry Unit, Department of Biochemistry, University of Oxford, Oxford, U.K
Address correspondence and reprint requests to Dr. Garth J.S. Cooper, School of Biological Sciences, University of Auckland,
Level 4, 3A Symonds St., Private Bag 92019, Auckland 1142, New Zealand. E-mail: g.cooper{at}auckland.ac.nz
Abstract
OBJECTIVE— Aggregation of human amylin (hA) into β-sheet–containing oligomers is linked to islet β-cell dysfunction and the pathogenesis
of type 2 diabetes. Here, we investigated possible contributions of Fas-associated death-receptor signaling to the mechanism
of hA-evoked β-cell apoptosis.
RESEARCH DESIGN AND METHODS— We measured responses to hA in isolated mouse islets and two insulinoma cell lines, wherein we measured Fas/Fas ligand (FasL)
and Fas-associated death domain (FADD) expression by quantitative RT-PCR, Western blotting, and immunofluorescence staining.
We used two anti-Fas/FasL blocking antibodies and the Fas/FasL antagonist Kp7–6 to probe roles of Fas interactions in the
regulation of apoptosis in hA-treated β-cells and measured Kp7–6–mediated effects on β-sheet formation and aggregation using
circular dichroism and thioflavin-T binding.
RESULTS— hA treatment stimulated Fas and FADD expression in β-cells. Both blocking antibodies suppressed hA-evoked apoptosis but did
not modify its aggregation. Therefore, Fas receptor interactions played a critical role in induction of this pathway. Interestingly,
hA-evoked β-cell apoptosis was suppressed and rescued by Kp7–6, which also impaired hA β-sheet formation.
CONCLUSIONS— This is the first report linking hA-evoked induction and activation of Fas and FADD to β-cell apoptosis. We have identified
a Fas/FasL antagonist, Kp7–6, as a potent inhibitor of hA aggregation and related β-cell death. These results also support
an interaction between hA and Fas on the surface of apoptotic β-cells. Increased expression and activation of Fas in β-cells
could constitute a molecular event common to the pathogenesis of both type 1 and type 2 diabetes, although the mode of pathway
activation may differ between these common forms of diabetes.
CD, circular dichroism
FADD, Fas-associated death domain
FasL, Fas ligand
hA, human amylin
HBSS, Hank's balanced salt solution
HFIP, 1,1,1,3,3,3-hexafluoro-2-propanol
JNK, Jun NH2-terminal kinase
qRT-PCR, quantitative RT-PCR
rA, rat amylin
ThT, thioflavin-T
Footnotes
Published ahead of print at http://diabetes.diabetesjournals.org on 31 October 2007. DOI: 10.2337/db07-0849.
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore
be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
Accepted October 22, 2007.
Received June 21, 2007.
DIABETES |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0012-1797 1939-327X |
DOI: | 10.2337/db07-0849 |