naphthoquinones and Brain-Ischemia

Plumbagin (PLB), an alkaloid obtained from the roots of the plants of Plumbago genus, is an inhibitor of NADPH oxidase 4 (NOX4). This study aimed to investigate the beneficial effect of PLB against oxygen-glucose deprivation/reoxygenation (OGDR)-induced neuroinjury in human SH-SY5Y neuronal cultures. Our results showed that OGD/R stimulated NOX4 protein expression and reactive oxygen species (ROS) production in SH-SY5Y cells, whereas increased 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA) production, resulting in the activation of the NLRP3 inflammasome. And PLB pretreatment reduced the ROS production by regulating the expression of NOX4 and downregulated NF-κB signaling which was induced by OGDR. Furthermore, PLB inhibited OGDR induced NLRP3 inflammasome activation but not PARP1. Overall, PLB improved OGDR induced neuroinjury by inhibiting NOX4-derived ROS-activated NLRP3 inflammasome.

Topics: Apoptosis; Brain Ischemia; Cell Hypoxia; Cell Line; Cell Survival; Glucose; Humans; Inflammasomes; Membrane Potential, Mitochondrial; NADPH Oxidase 4; Naphthoquinones; Neurons; NF-kappa B; NLR Family, Pyrin Domain-Containing 3 Protein; Oxidative Stress; Plant Extracts; Plant Roots; Plumbaginaceae; Reactive Oxygen Species

Deregulation of glutamate homeostasis is associated with degenerative neurological disorders. Glutamate dehydrogenase (GDH) is important for glutamate metabolism and plays a central role in expanding the pool of tricarboxylic acid (TCA) cycle intermediate alpha-ketoglutarate (α-KG), which improves overall bioenergetics. Under high energy demand, maintenance of ATP production results in functionally active mitochondria. Here, we tested whether the modulation of GDH activity can rescue ischemia/reperfusion-induced neuronal death in an in vivo mouse model of middle artery occlusion and an in vitro oxygen/glucose depletion model. Iodoacetate, an inhibitor of glycolysis, was also used in a model of energy failure, remarkably depleting ATP and α-KG. To stimulate GDH activity, the GDH activator 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid and potential activator beta-lapachone were used. The GDH activators restored α-KG and ATP levels in the injury models and provided potent neuroprotection. We also found that beta-lapachone increased glutamate utilization, accompanied by a reduction in extracellular glutamate. Thus, our hypothesis that mitochondrial GDH activators increase α-KG production as an alternative energy source for use in the TCA cycle under energy-depleted conditions was confirmed. Our results suggest that increasing GDH-mediated glutamate oxidation represents a new therapeutic intervention for neurodegenerative disorders, including stoke.

Topics: Animals; Astrocytes; Brain; Brain Ischemia; Cell Death; Cells, Cultured; Coculture Techniques; Disease Models, Animal; Glutamate Dehydrogenase; Infarction, Middle Cerebral Artery; Male; Mice, Inbred ICR; Mitochondria; Naphthoquinones; Neurons; Neuroprotective Agents; Random Allocation; Reperfusion Injury

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and represents a new target for treatment of stroke. Shikonin has gained attention for its prominent anti-inflammatory property, but up to now little is known about shikonin treatment in acute ischemic stroke. The aim of this study was to evaluate the potential neuroprotective role of shikonin in cerebral ischemic injury, and investigate whether shikonin modulated inflammatory responses after stroke. Focal cerebral ischemia in male ICR mice was induced by transient middle cerebral artery occlusion. Shikonin (10 and 25 mg/kg) was administered by gavage once a day for 3 days before surgery and another dosage after operation. Neurological deficit, infarct volume, brain edema, blood-brain barrier (BBB) dysfunction, and inflammatory mediators were evaluated at 24 and 72 h after stroke. Compared with vehicle group, 25 mg/kg shikonin significantly improved neurological deficit, decreased infarct volume and edema both at 24 and 72 h after transient ischemic stroke, our data also showed that shikonin inhibited the pro-inflammatory mediators, including TLR4, TNF-α, NF-κB, and phosphorylation of p38MAPK in ischemic cortex. In addition, shikonin effectively alleviated brain leakage of Evans blue, up-regulated claudin-5 expression, and inhibited the over-expressed MMP-9 in ischemic brain. These results suggested that shikonin effectively protected brain against ischemic damage by regulating inflammatory responses and ameliorating BBB permeability.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Blood-Brain Barrier; Brain Ischemia; Claudin-5; Down-Regulation; Infarction, Middle Cerebral Artery; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred ICR; Naphthoquinones; Neuroprotective Agents; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Stroke; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha; Up-Regulation

2-Methoxystypandrone (2-MS), a naphthoquinone, has been shown to display an immunomodulatory effect in a cellular model. To explore whether 2-MS could protect mice against cerebral ischemic/reperfusion (I/R)-induced brain injury, we evaluated 2-MS's protective effects on an acute ischemic stroke by inducing a middle cerebral artery occlusion/reperfusion (MCAO) injury in murine model. Treatment of mice that have undergone I/R injury with 2-MS (10-100 μg/kg, i.v.) at 2 h after MCAO enhanced survival rate and ameliorated neurological deficits, brain infarction, neural dysfunction and massive oxidative stress, due to an enormous production of free radicals and breakdown of blood-brain barrier (BBB) by I/R injury; this primarily occurred with extensive infiltration of CD11b-positive inflammatory cells and upexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and p65 nuclear factor-kappa B (NF-κB). All of these pathological changes were diminished by 2-MS; 2-MS also intensively limited cortical infarction and promoted upexpression of neurodevelopmental genes near peri-infarct cortex and endogenous neurogenesis near subgranular zone of hippocampal dentate gyrus and the subventricular zone, most possibly by inactivation of GSK3β which in turn upregulating β-catenin, Bcl-2 adam11 and adamts20. We conclude that 2-MS blocks inflammatory responses by impairing NF-κB signaling to limit the inflammation and oxidative stress for preservation of BBB integrity; 2-MS also concomitantly promotes neurodevelopmental protein expression and endogenous neurogenesis through inactivation of GSK3β to enhance β-catenin signaling for upexpression of neuroprotective genes and proteins.

Topics: Animals; Blood-Brain Barrier; Brain; Brain Ischemia; CD11b Antigen; Cyclooxygenase 2; Doublecortin Protein; Gene Expression Regulation; Immunologic Factors; Leukocytes; Male; Mice; Mice, Inbred ICR; Molecular Structure; Naphthoquinones; Neurogenesis; Nitric Oxide Synthase Type II; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Stroke; Transcription Factor RelA

Sublethal preconditioning ischemia protects neurons from lethal ischemia, and activation of ERK is associated with this protection. However, sublethal ischemia and reperfusion also results in rapid inactivation of ERK, which contributes to the dual-phase activation profile of ERK. In the present study, we observed sublethal ischemia-induced rapid inactivation of ERK was accompanied by phosphorylation of Raf-1 at Ser289/296/301 sites. Inhibition of calcium signaling by ketamine resulted in down-regulation of the Raf-1/ERK cascade and decreased phosphorylation of Raf-1 at Ser289/296/301. The MEK inhibitor U0126 suppressed ERK activity and phosphorylation of Raf-1 at Ser289/296/301 but not Raf-1 activation elicited by its dephosphorylation at S259 following ischemia. The PP2A inhibitor cantharidin but not Pin1 inhibitor juglone blocked Raf-1 dephosphorylation at Ser289/296/301 and ERK dephosphorylation and led to ERK sustained activation, which is associated with transcriptional up-regulation of genes related to differentiation. Furthermore, dual-phase activation of ERK did not alter the mRNA levels of genes related to proliferation or differentiation. These results indicate the initial robust activation of ERK phosphorylates Raf-1 at Ser289/296/301, resulting in Raf-1inhibition and then prompt inactivation of ERK following sublethal preconditioning ischemia. Dual-phase activation of ERK may exert its neuroprotection against lethal ischemia through blocking cell proliferation and differentiation.

Topics: Animals; Brain Ischemia; Calcium; Cantharidin; Enzyme Activation; Enzyme Inhibitors; Excitatory Amino Acid Antagonists; Extracellular Signal-Regulated MAP Kinases; Feedback, Physiological; Hippocampus; Ketamine; Male; MAP Kinase Kinase Kinases; MAP Kinase Signaling System; Mitogen-Activated Protein Kinase Kinases; Naphthoquinones; Protein Isoforms; Protein Phosphatase 2; Proto-Oncogene Proteins c-raf; Rats; Rats, Sprague-Dawley

The aim of our study was to investigate the neuroprotective properties of shikonin, a naphthoquinone pigment isolated from the roots of the traditional Chinese herb Lithospermum erythrorhizon. In the present study, mice were divided randomly into sham, model, shikonin and edaravone-treated groups. Shikonin (50, 25, and 12.5mg/kg, i.g.) or maize oil was administered three times before ischemia and once at 2h after the onset of ischemia. Mice were anesthetized with chloral hydrate and subjected to middle cerebral artery 2h of occlusion and then 22h of reperfusion. Different antioxidant assays were employed in order to evaluate the antioxidant activities of shikonin in vitro. Neurological deficit, infarct size, histopathology changes and oxidative stress markers were evaluated after 22h of reperfusion. In comparison with the model group, treatment with shikonin significantly decreased neurological deficit scores, infarct size, the levels of malondialdehyde(MDA), carbonyl and reactive oxygen species, and attenuated neuronal damage, up-regulated superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) activities and reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio. Taken together, these results suggested that the neuroprotective effects of shikonin against cerebral ischemia/reperfusion injury may be attributed to its antioxidant effects.

Topics: Animals; Antioxidants; Biomarkers; Brain Ischemia; Dose-Response Relationship, Drug; Glutathione; Infarction, Middle Cerebral Artery; Male; Malondialdehyde; Mice; Mitochondria; Naphthoquinones; Neuroprotective Agents; Oxidative Stress; Oxidoreductases; Protein Carbonylation; Random Allocation; Reactive Oxygen Species; Reperfusion Injury; Up-Regulation

The changes developing in the perifocal area of hematoma and perspectives of antioxidant and chelate therapy were studied on the model of experimental hemorrhagic stroke and in clinical conditions. Microcirculatory, ischemic and inflammation disturbances with a certain time sequence were found in the perifocal areas. These changes, along with hypostasis and oxidative stress, form the pathobiochemical cascade of changes in hemorrhagic stroke and are potential therapeutic targets. Administering of an antioxidant and chelate drug histochrome reduces the intensity of changes in the perifocal area in the experimental conditions. In clinical conditions, it accelerates the dynamics of brain and meningeal symptoms regression and improves the blood rheological properties.

Topics: Animals; Antioxidants; Brain Ischemia; Cerebral Hemorrhage; Chelating Agents; Male; Naphthoquinones; Platelet Aggregation Inhibitors; Rats; Rats, Wistar