ABSTRACT
The present study tested the cytoprotective effect of methyleugenol in an in vivo ischemia model (i.e. middle cerebral artery occlusion (MCAO) for 1.5 h and subsequent reperfusion for 24 h) and further investigated its mechanism of action in in vitro cerebral ischemic models. When applied shortly after reperfusion, methyleugenol largely reduced cerebral ischemic injury. Methyleugenol decreased the caspase-3 activation and death of cultured cerebral cortical neurons caused by oxygen-glucose deprivation (OGD) for 1 h and subsequent re-oxygenation for 24 h. Methyleugenol markedly reduced superoxide generation in the ischemic brain and decreased the intracellular oxidative stress caused by OGD/re-oxygenation. It was found that methyleugenol elevated the activities of superoxide dismutase and catalase. Further, methyleugenol inhibited the production of nitric oxide and decreased the protein expression of inducible nitric oxide synthase. Methyleugenol down-regulated the production of pro-inflammatory cytokines in the ischemic brain as well as in immunostimulated mixed glial cells. The results indicate that methyleugenol could be useful for the treatment of ischemia/inflammation-related diseases.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Brain Ischemia/drug therapy , Brain Ischemia/prevention & control , Eugenol/analogs & derivatives , Inflammation/drug therapy , Oxidative Stress/drug effects , Animals , Brain Ischemia/metabolism , Brain Ischemia/pathology , Cells, Cultured , Cytokines/biosynthesis , Disease Models, Animal , Dose-Response Relationship, Drug , Eugenol/pharmacology , Free Radicals/analysis , Glucose/metabolism , Inflammation/immunology , Male , Neurons/drug effects , Oxidative Stress/immunology , Oxygen/metabolism , Rats , Rats, Sprague-Dawley , Superoxides/metabolismABSTRACT
Mitogen-activated protein (MAP) kinase phosphatase-1 (MKP-1) is a dual specificity phosphatase that negatively regulates the MAP kinases. In this study, we found that levels of MKP-1 expression were transiently decreased within 3h, followed by an increase 6-9h after H2O2-induced oxidative stress in human neuroblastoma SH-SY5Y cells. There was a strong negative correlation between MKP-1 expression and ERK1/2 phosphorylation levels. Treatment of cells with a proteasomal inhibitor MG132 decreased the oxidative stress-induced degradation of MKP-1, resulting in dephosphorylation of ERK1/2. MG132 potentiated hydrogen peroxide-induced cell death, which was attenuated by a phosphatase inhibitor sodium orthovanadate. Suppression of MKP-1 expression by transfection with siRNA duplexes specific to MKP-1 transcript resulted in a decrease in oxidative stress-induced cell death. These data therefore suggest that MKP-1, a negative regulator of ERK1/2, plays a proapoptotic role in oxidative stress-induced cell death in a neuronal cell line.
Subject(s)
Apoptosis/physiology , Cell Cycle Proteins/physiology , Extracellular Signal-Regulated MAP Kinases/antagonists & inhibitors , Immediate-Early Proteins/physiology , Oxidative Stress/physiology , Phosphoprotein Phosphatases/physiology , Protein Tyrosine Phosphatases/physiology , Cell Cycle Proteins/biosynthesis , Cell Cycle Proteins/genetics , Dual Specificity Phosphatase 1 , Enzyme Induction , Humans , Hydrogen Peroxide/pharmacology , Immediate-Early Proteins/biosynthesis , Immediate-Early Proteins/genetics , Neuroblastoma/enzymology , Phosphoprotein Phosphatases/biosynthesis , Phosphoprotein Phosphatases/genetics , Proteasome Endopeptidase Complex/metabolism , Protein Phosphatase 1 , Protein Tyrosine Phosphatases/biosynthesis , Protein Tyrosine Phosphatases/genetics , RNA, Small Interfering/pharmacology , Tumor Cells, Cultured , Ubiquitin/metabolismABSTRACT
We examined neuroprotective effects of naturally occurring biflavonoids on oxidative stress-induced and amyloid beta peptide-induced cell death in neuronal cells. Among the nine biflavonoids tested, amentoflavone, ginkgetin, and isoginkgetin exhibited strong neuroprotection against cytotoxic insults induced by oxidative stress and amyloid beta, suggesting their therapeutic potential against neurodegenerative diseases, including ischemic stroke and Alzheimer's disease.
Subject(s)
Biflavonoids/pharmacology , Cell Death/drug effects , Neurons/drug effects , Neuroprotective Agents/pharmacology , Oxidative Stress/drug effects , Alzheimer Disease/drug therapy , Amyloid beta-Peptides/metabolism , Amyloid beta-Peptides/pharmacology , Biflavonoids/chemistry , Brain Ischemia/drug therapy , Dose-Response Relationship, Drug , Humans , Neurodegenerative Diseases/drug therapy , Neurons/cytology , Neuroprotective Agents/chemistry , Tumor Cells, CulturedABSTRACT
Neuroprotective effects of flavones were examined. Luteolin and apigenin exhibited neuroprotection against oxidative stress-induced cell death in SH-SY5Y cells. Free radical scavenging activity and neuroprotection assays revealed that flavones exerted their neuroprotective effects via the direct interaction with the apoptotic caspase pathway independently of their antioxidant activity.