Involvement of nitric oxide in glucose toxicity on differentiated PC12 cells: prevention of glucose toxicity by tetrahydrobiopterin, a cofactor for nitric oxide synthase.
Effects of high concentrations of glucose on cell survival of differentiated PC12 cells were examined. Seven day-culture with D-glucose (9.0-27.0 mg/ml as 2-6-fold of the optimal level) induced cell death in a dose-related manner but 3-day culture with high concentrations of glucose had no effect on cell viability. L-glucose had no effect on viability of PC12 cells, suggesting that D-glucose toxicity was independent of its osmolarity effect. Seven-day culture with D-glucose (13.5 mg/ml as 3-fold of the optimal level) increased nitric oxide metabolites (NOx) in the culture medium. Glucose-induced increase in NOx was eliminated by 0.1 mM L-nitro-arginine methylester (L-NAME), a nitric oxide synthase (NOS) inhibitor. Intracellular Ca(2+) concentration was increased by D-glucose in a dose-related manner, suggesting that D-glucose activated NOS by increasing intracellular Ca(2+) concentration in PC12 cells. Glucose-induced cell death was blunted by 0.1 mM L-NAME, showing that nitric oxide (NO) was involved in the glucose toxicity to PC12 cells. Tetrahydrobiopterin (BH(4)), a cofactor for NOS, attenuated both glucose-induced cell death and NOx production at 1 microM but not at 10 microM. The effects of BH(4) on glucose-induced cell death and NOx production were not mimicked by reducing agents such as ascorbate and cysteine. These results taken together suggest that high concentrations of glucose induced cell death via NO production and that low concentration of BH(4) had a protective effect against glucose neurotoxicity in differentiated PC12 cells.
Koshimura
Kunio
K
Department of Medicine, First Division, Shimane Medical University, Izumo, Japan. kunio@shimane-med.ac.jp
Tanaka
Junko
J
Murakami
Yoshio
Y
Kato
Yuzuru
Y
D000818:Animals; D001708:Biopterins / Q000031:analogs & derivatives* / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003929:Diabetic Neuropathies / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism* / Q000633:toxicity; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009420:Nervous System / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats
D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D001708:Biopterins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; C003402:sapropterin; D005947:Glucose; D019331:NG-Nitroarginine Methyl Ester