p38MAPK and ERK promote nitric oxide production in cultured human retinal pigmented epithelial cells induced by high concentration glucose.
Increased nitric oxide (NO) has been correlated with diabetic retinopathy. In this study we investigated the cell injury, production of NO in retinal pigment epithelial (RPE) cells exposed to increased glucose concentration, and its molecular mechanism involved. Cultured human RPE cells (ARPE-19) were exposed for 4 days with normal blood glucose concentration (5.5mM D-glucose), followed by exposure to either normal (5.5mM) or high (33 mM) concentrations of D-glucose for 48 h. To determine the cytotoxicity of high glucose, cell viability, ROS production and SOD activity were measured, respectively. The end product of NO (nitrite and nitrate) was determined by a colorimetric assay and nitrotyrosine levels were quantified by a competitive ELISA. The expression of iNOS and the activation of p38MAPK, ERK and JNK were analyzed by Western blot. Treatment of RPE cells with high glucose-induced a significant increased of iNOS, accompanied by an increase in cell damage, NO and nitrotyrosine levels. High glucose caused activation of p38MAPK and ERK, inhibition for p38MAPK and ERK abrogated the high glucose-induced increase in iNOS, cell injury and levels of NO and nitrotyrosine. High glucose causes increased cell damage and NO generation in RPE cells by a process of iNOS expression that requires the activation of p38MAPK and ERK.
Department of Ophthalmology, First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.
Zhilan
Z
Yuan
Weiyan
W
Feng
Jin
J
Hong
Qi
Q
Zheng
Jie
J
Shuai
Yingbin
Y
Ge
D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D003930:Diabetic Retinopathy / Q000503:physiopathology; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D015415:Biomarkers; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D007770:L-Lactate Dehydrogenase; D052248:Nitric Oxide Synthase Type I; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D013482:Superoxide Dismutase; D048049:Extracellular Signal-Regulated MAP Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D005947:Glucose