8-hydroxy-2--deoxyguanosine and Encephalitis

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acute Disease; Biomarkers; Child; Cytochromes c; Deoxyguanosine; Electroencephalography; Encephalitis; Humans; Interleukin-6; Monitoring, Physiologic; Mutation; NAV1.2 Voltage-Gated Sodium Channel; Nerve Growth Factors; Phosphopyruvate Hydratase; Prognosis; Research; S100 Calcium Binding Protein beta Subunit; Voltage-Gated Sodium Channel beta-1 Subunit

We examined oxidative stress markers, tau protein and cytokines in the cerebrospinal fluid (CSF) in six patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS). In the CSF, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and hexanoyl-lysine adduct levels increased over the cutoff index in four and one out of six MERS patients, respectively. The CSF IL-6 and IL-10 levels were increased in three out of six patients, two of which had extended lesion of the cerebral white matter. The CSF value of tau protein, marker of the axonal damage, was not increased, and neuron specific enolase (NSE) in the CSF was not increased. The increased 8-OHdG levels in the CSF, DNA oxidative stress marker, in four MERS patients, suggesting involvement of oxidative stress in MERS. MERS is occasionally accompanied with hyponatremia, although our patients lacked hyponatremia. It is possible that the disequilibrium of systemic metabolism including electrolytes may lead to facilitation of oxidative stress and reversible white matter lesion in MERS. The increase of cytokine production seems to be involved in the distribution of lesions in MERS.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Brain Diseases; Child; Child, Preschool; Corpus Callosum; Cytokines; Deoxyguanosine; Encephalitis; Enzyme-Linked Immunosorbent Assay; Female; Humans; Infant; Magnetic Resonance Imaging; Male; Oxidative Stress; Phosphopyruvate Hydratase; Radioimmunoassay; Sodium; tau Proteins

While free radicals and inflammation constitute major routes of neuronal injury occurring in amyotrophic lateral sclerosis (ALS), neither antioxidants nor non-steroidal anti-inflammatory drugs have shown significant efficacy in human clinical trials. We examined the possibility that concurrent blockade of free radicals and prostaglandin E(2) (PGE(2))-mediated inflammation might constitute a safe and effective therapeutic approach to ALS. We have developed 2-hydroxy-5-[2-(4-trifluoromethylphenyl)-ethylaminobenzoic acid] (AAD-2004) as a derivative of aspirin. AAD-2004 completely removed free radicals at 50 nM as a potent spin-trapping molecule and inhibited microsomal PGE(2) synthase-1 (mPGES-1) activity in response to both lipopolysaccharide-treated BV2 cell with IC(50) of 230 nM and recombinant human mPGES-1 protein with IC(50) of 249 nM in vitro. In superoxide dismutase 1(G93A) transgenic mouse model of ALS, AAD-2004 blocked free radical production, PGE(2) formation, and microglial activation in the spinal cords. As a consequence, AAD-2004 reduced autophagosome formation, axonopathy, and motor neuron degeneration, improving motor function and increasing life span. In these assays, AAD-2004 was superior to riluzole or ibuprofen. Gastric bleeding was not induced by AAD-2004 even at a dose 400-fold higher than that required to obtain maximal therapeutic efficacy in superoxide dismutase 1(G93A). Targeting both mPGES-1-mediated PGE(2) and free radicals may be a promising approach to reduce neurodegeneration in ALS and possibly other neurodegenerative diseases.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Amyotrophic Lateral Sclerosis; Analysis of Variance; Animals; Anti-Inflammatory Agents, Non-Steroidal; Aspirin; Calcium-Binding Proteins; Cerebral Cortex; Deoxyguanosine; Dinoprostone; Disease Models, Animal; Encephalitis; Free Radical Scavengers; Free Radicals; Gene Expression Regulation; Humans; Ibuprofen; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microfilament Proteins; Microglia; Motor Neurons; Oxidative Stress; Riluzole; Spinal Cord; Sulfasalazine; Superoxide Dismutase; Tyrosine

Our previous studies have shown that ferulic acid (4-hydroxy-3-methoxycinnamic acid, FA) inhibits intercellular adhesion molecule-1 (ICAM-1) expression in the ischemic striatum after 2 h of reperfusion in a transient middle cerebral artery occlusion model in rats. The purpose of this study is to further investigate the neuroprotective effects of FA during reperfusion after cerebral ischemia. Rats were subjected to 90 min of ischemia; they were then sacrificed after 2, 10, 24 and 36 h of reperfusion. ICAM-1 and macrophage-1 antigen (Mac-1) mRNA were detected using semi-quantitative RT-PCR at 2 h of reperfusion. Mac-1, 4-hydroxy-2-nonenal (4-HNE), 8-hydroxy-2'-deoxyguanosine (8-OHdG), active caspase 3, neuronal nuclei (NeuN) and TUNEL positive cells were measured at 2, 10, 24 and 36 h of reperfusion. FA (100 mg/kg, i.v.) administered immediately after MCAo inhibited ICAM-1 and Mac-1 mRNA expression in the striatum at 2 h of reperfusion, and reduced the number of Mac-1, 4-HNE and 8-OHdG positive cells in the ischemic rim and core at 10, 24 and 36 h of reperfusion. FA decreased TUNEL positive cells in the penumbra at 10 h, and in the ischemic boundary and core at 24 and 36 h of reperfusion. FA curtailed active caspase 3 expression in the penumbra at 10 h and restored NeuN-labeled neurons in the penumbra and ischemic core at 36 h of reperfusion. FA decreased the level of ICAM-1 mRNA and the number of microglia/macrophages, and subsequently down-regulated inflammation-induced oxidative stress and oxidative stress-related apoptosis, suggesting that FA provides neuroprotection against oxidative stress-related apoptosis by inhibiting ICAM-1 mRNA expression after cerebral ischemia/reperfusion injury in rats.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Apoptosis; Brain Ischemia; Caspase 3; Coumaric Acids; Deoxyguanosine; Disease Models, Animal; DNA-Binding Proteins; Encephalitis; Free Radical Scavengers; Gene Expression; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Intercellular Adhesion Molecule-1; Macrophage-1 Antigen; Male; Nerve Tissue Proteins; Neuroprotective Agents; Nuclear Proteins; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger

To elucidate the roles of 8-hydroxydeoxyguanosine (oh(8)dG), the nucleoside of 8-hydroxyguanine (oh(8)Gua), we examined the effects of oh(8)dG upon LPS-induced intercellular adhesion molecule-1 (ICAM-1) expression and the underlying mechanisms in brain microglial cells. We found that oh(8)dG reduces LPS-induced reactive oxygen species (ROS) production, STAT3 activation, and ICAM-1 expression. oh(8)dG also suppresses pro-inflammatory cytokines, such as TNF-alpha, IL-6 and IFN-gamma. Overexpression of dominant negative STAT3 completely diminshed STAT3-mediated ICAM-1 transcriptional activity. Chromatin immunoprecipitation studies revealed that oh(8)dG inhibited recruitment of STAT3 to the ICAM-1 promoter, followed by a decrease in ICAM-1 expression. Using mice lacking a functional Toll-like receptor 4 (TLR4), we demonstrated that, while TLR4+/+ microglia were activated by LPS, TLR4-/- microglia exhibited inactivated STAT3 in response to LPS. Evidently, LPS modulates STAT3-dependent ICAM-1 induction through TLR4-mdiated cellular responses. Oh(8)dG apparently plays a role in anti-inflammatory actions via suppression of ICAM-1 gene expression by blockade of the TLR4-STAT3 signal cascade in inflammation-enhanced brain microglia. Therefore, oh(8)dG in the cytosol probably functions as an anti-inflammatory molecule and should be considered as a candidate for development of anti-inflammatory agents.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Anti-Inflammatory Agents, Non-Steroidal; Brain; Cell Survival; Cytokines; Deoxyguanosine; Encephalitis; Inflammation Mediators; Intercellular Adhesion Molecule-1; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microglia; Reactive Oxygen Species; STAT3 Transcription Factor; Toll-Like Receptor 4

The effects of the peripheral benzodiazepine receptor (PBR) ligand, PK11195, were investigated in the rat striatum following the administration of quinolinic acid (QUIN). Intrastriatal QUIN injection caused an increase of PBR expression in the lesioned striatum as demonstrated by immunohistochemical analysis. Double immunofluorescent staining indicated PBR was primarily expressed in ED1-immunoreactive microglia but not in GFAP-immunoreactive astrocytes or NeuN-immunoreactive neurons. PK11195 treatment significantly reduced the level of microglial activation and the expression of pro-inflammatory cytokines and iNOS in QUIN-injected striatum. Oxidative-mediated striatal QUIN damage, characterized by increased expression of markers for lipid peroxidation (4-HNE) and oxidative DNA damage (8-OHdG), was significantly diminished by PK11195 administration. Furthermore, intrastriatal injection of PK11195 with QUIN significantly reduced striatal lesions induced by the excitatory amino acid and diminished QUIN-mediated caspase-3 activation in striatal neurons. These results suggest that inflammatory responses from activated microglia are damaging to striatal neurons and pharmacological targeting of PBR in microglia may be an effective strategy in protecting neurons in neurological disorders such as Huntington's disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aldehydes; Animals; Antineoplastic Agents; Carrier Proteins; Caspases; Corpus Striatum; Cytokines; Deoxyguanosine; Disease Models, Animal; Ectodysplasins; Encephalitis; Gliosis; Huntington Disease; Isoquinolines; Ligands; Male; Membrane Proteins; Microglia; Nerve Degeneration; Neurotoxins; Nitric Oxide Synthase Type II; Oxidative Stress; Quinolinic Acid; Rats; Rats, Sprague-Dawley; Receptors, GABA-A; Tumor Necrosis Factors