Differential effect of sulfonylureas on production of reactive oxygen species and apoptosis in cultured pancreatic beta-cell line, MIN6.
Sulfonylureas are considered to cause beta-cell apoptosis. However, it is unclear how this occurs and whether there is a difference in such effects among various sulfonylureas. Here, we examined the effects of various sulfonylureas and a short-acting insulin secretagogue, nateglinide, on oxidative stress and apoptosis using the beta-cell line MIN6. After cultured MIN6 cells were exposed to various concentrations of sulfonylureas (glibenclamide, glimepiride, and gliclazide) or nateglinide, intracellular production of reactive oxygen species (ROS) was evaluated by staining with 2',7'-dichlorofluorescein diacetate. The effect of these agents on apoptosis was also evaluated by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labeling technique. Exposure of beta-cells to glibenclamide, glimepiride, and nateglinide significantly increased intracellular ROS production in a concentration-dependent manner (0.1-10 micromol/L). These effects were completely blocked by nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase inhibitors (diphenylene iodonium or apocynin) or a protein kinase C inhibitor (calphostin C). After exposure to these agents for 48 hours, the numbers of apoptotic cells were also significantly increased. These effects were significantly blocked by apocynin and antioxidant N-acetyl-L-cysteine. In contrast, exposure to any concentrations of gliclazide did not affect either intracellular ROS production or the numbers of apoptotic cells. Sulfonylureas (glibenclamide and glimepiride, but not gliclazide) and nateglinide stimulated ROS production via protein kinase C-dependent activation of NAD(P)H oxidase and consequently caused beta-cell apoptosis in vitro. Because of the lack of such adverse effects, gliclazide may have a benefit in the preservation of functional beta-cell mass.
Sawada
Fumi
F
Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
Inoguchi
Toyoshi
T
Tsubouchi
Hirotaka
H
Sasaki
Shuji
S
Fujii
Masakazu
M
Maeda
Yasutaka
Y
Morinaga
Hidetaka
H
Nomura
Masatoshi
M
Kobayashi
Kunihisa
K
Takayanagi
Ryoichi
R
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D003510:Cyclohexanes / Q000494:pharmacology; D005452:Fluoresceins / Q000737:chemistry; D005907:Gliclazide / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D019255:NADPH Oxidases / Q000378:metabolism; D000077715:Nateglinide; D010649:Phenylalanine / Q000031:analogs & derivatives / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013453:Sulfonylurea Compounds / Q000494:pharmacology*
D003510:Cyclohexanes; D005452:Fluoresceins; D007004:Hypoglycemic Agents; D017382:Reactive Oxygen Species; D013453:Sulfonylurea Compounds; C029569:diacetyldichlorofluorescein; D000077715:Nateglinide; D010649:Phenylalanine; C057619:glimepiride; D019255:NADPH Oxidases; D011493:Protein Kinase C; D005907:Gliclazide; D005905:Glyburide