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Poly(ADP-ribose) synthesis induced by nitric oxide in a mouse beta-cell line
1Department of Medicine, Kurume University School of Medicine, Fukuoka, Japan.
Life Sciences
|January 1, 1995
Summary
Nitric oxide (NO) may damage pancreatic beta cells in Type 1 diabetes by activating poly(ADP-ribose) synthetase. This enzyme activation depletes nicotinamide adenine dinucleotide (NAD) levels, contributing to beta-cell dysfunction.
Area of Science:
- Immunology
- Endocrinology
- Biochemistry
Background:
- Nitric oxide (NO) is recognized as an immunological effector molecule.
- NO is implicated in the beta-cell dysfunction characteristic of Type 1 diabetes.
Purpose of the Study:
- To investigate whether nitric oxide (NO) induces poly(ADP-ribose) synthesis in pancreatic islet cells.
- To elucidate the mechanism of NO-mediated beta-cell damage.
Main Methods:
- Exposure of mouse islet cells and a beta-cell line (beta TC1) to nitroprusside.
- Measurement of intracellular nicotinamide adenine dinucleotide (NAD) levels.
- Assay of poly(ADP-ribose) synthetase activity.
- Assessment of the effects of 3-aminobenzamide, a poly(ADP-ribose) synthetase inhibitor.
Main Results:
- Nitroprusside exposure led to reduced intracellular NAD levels in islet cells.
- Poly(ADP-ribose) synthetase activity was stimulated by nitroprusside in beta TC1 cells.
- 3-aminobenzamide inhibited both the decrease in NAD and poly ADP-ribosylation.
Conclusions:
- NO-induced pancreatic beta-cell damage is likely mediated by the activation of poly(ADP-ribose) synthetase.
- The activation of this enzyme leads to a depletion of NAD content, causing cellular damage.