Fatty acid-induced β cell apoptosis: A link between obesity and diabetes

Michio Shimabukuro, Yan Ting Zhou, Moshe Levi, Roger H Unger

Research output: Contribution to journalArticlepeer-review

956 Scopus citations

Abstract

Like obese humans, Zucker diabetic fatty (ZDF) rats exhibit early β cell compensation for insulin resistance (4-fold β cell hyperplasia) followed by decompensation (> 50% loss of β cells). In prediabetic and diabetic ZDF islets, apoptosis measured by DNA laddering is increased 3-and >7-fold, respectively, compared with lean ZDF controls. Ceramide, a fatty acid-containing messenger in cytokine-induced apoptosis, was significantly increased (P < 0.01) in prediabetic and diabetic islets. Free fatty acids (FFAs) in plasma are high (>1 mM) in prediabetic and diabetic ZDF rats; therefore, we cultured prediabetic islets in 1 mM FFA. DNA laddering rose to 19.6% vs. 4.6% in lean control islets, preceded by an 82% increase in ceramide. C2-Ceramide without FFA induced DNA laddering, but fumonisin B1, a ceramide synthetase inhibitor, completely blocked FFA-induced DNA laddering in cultured ZDF islets. [3H]Palmitate incorporation in [3H]ceramide in ZDF islets was twice that of controls, but [3H] palmitate oxidation was 77% less. Triacsin C, an inhibitor of fatty acyl-CoA synthetase, and troglitazone, an enhancer of Flea oxidation in ZDF islets, both blocked DNA laddering. These agents also reduced inducible nitric oxide (NO) synthase mRNA and NO production, which are involved in FFA-induced apoptosis. In ZDF obesity, β cell apoptosis is induced by increased FFA via de novo ceramide formation and increased NO production.

Original languageEnglish (US)
Pages (from-to)2498-2502
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume95
Issue number5
DOIs
StatePublished - Mar 3 1998

ASJC Scopus subject areas

  • General

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