Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heat stroke-induced death is a major killer worldwide. Mice were subjected to acute heat stress by exposing them to whole-body hyperthermia (WBH) treatment and were used as a model to study heat stroke. Administration of L-arginine (L-arg, 120 mg/kg, i.p) 2 h after the cessation of WBH rescued the mice from heat-induced death and reduced the hypothermia. Heat shock protein 70 levels in the liver were increased significantly in heat-stressed mice administered L-arg compared with the heat-stressed group. WBH induced apoptosis, as indicated by DNA fragmentation, and increased levels of p53 and caspase-3 activity, which were significantly reduced by the administration of L-arg. The levels of inducible nitric oxide synthase in the liver, nitrite, and inflammatory cytokines like interleukin 1beta and tumor necrosis factor-alpha in the serum increased in WBH-treated mice. The levels of the above markers of heat stress significantly decreased in L-arg-treated mice. Kinin-B1 receptor (kinin-B1R) in cardiac tissue that is upregulated in heat stressed mice was significantly lower in L-arg-administered mice. These data suggest the potential use of L-arg, a nonessential amino acid that is used as an enteral diet supplement, to treat heat stroke-related injury when administered at the appropriate dose and time.
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PMID:Therapeutic treatment with L-arginine rescues mice from heat stroke-induced death: physiological and molecular mechanisms. 1620 19

Neuregulins are a family of growth factor domain proteins that are structurally related to the epidermal growth factor. Accumulating evidence has shown that neuregulins have cyto- and neuroprotective properties in various cell types. In particular, the neuregulin-1 Beta (NRG1-Beta) isoform is well documented for its antiinflammatory properties in rat brain after acute stroke episodes. Pentachlorophenol (PCP) is an organochlorine compound that has been widely used as a biocide in several industrial, agricultural, and domestic applications. Previous investigations from our laboratory have demonstrated that PCP exerts both cytotoxic and mitogenic effects in human liver carcinoma (HepG2) cells, primary catfish hepatocytes and AML 12 mouse hepatocytes. We have also shown that in HepG2 cells, PCP has the ability to induce stress genes that may play a role in the molecular events leading to toxicity and tumorigenesis. In the present study, we hypothesize that NRG1-Beta will exert its cytoprotective effects in PCP-treated AML 12 mouse hepatocytes by its ability to suppress the toxic effects of PCP. To test this hypothesis, we performed the MTT-cell respiration assay to assess cell viability, and Western-blot analysis to assess stress-related proteins as a consequence of PCP exposure. Data obtained from 48 h-viability studies demonstrated a biphasic response; showing a dose-dependent increase in cell viability within the range of 0 to 3.87 microg/mL, and a gradual decrease within the concentration range of 7.75 to 31.0 microg/mL in concomitant treatments of NRG1-Beta+PCP and PCP. Cell viability percentages indicated that NRG1-Beta+PCPtreated cells were not significantly impaired, while PCP-treated cells were appreciably affected; suggesting that NRG1-Beta has the ability to suppress the toxic effects of PCP. Western Blot analysis demonstrated the potential of PCP to induce oxidative stress and inflammatory response (c-fos), growth arrest and DNA damage (GADD153), proteotoxic effects (HSP70), cell cycle arrest as consequence of DNA damage (p53), mitogenic response (cyclin- D1), and apoptosis (caspase-3). NRG1-Beta exposure attenuated stress-related protein expression in PCP-treated AML 12 mouse hepatocytes. Here we provide clear evidence that NRG1-Beta exerts cytoprotective effects in AML 12 mouse hepatocytes exposed to PCP.
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PMID:Neuregulin 1-Beta cytoprotective role in AML 12 mouse hepatocytes exposed to pentachlorophenol. 1682 72

Although the role of the tumor suppressor gene p53 is well known in cancer, recent studies have highlighted a fundamental role for p53 in regulating cells in the advanced atherosclerotic plaque, the major cause of heart attacks and stroke. In particular, p53 is activated in the complex environment of the plaque, in part by DNA damage within the lesion, and regulates growth arrest, cell senescence and apoptosis of vascular smooth muscle cells (VSMCs). The role of endogenous p53 has been determined using p53 knockout in mice developing advanced atherosclerosis, using bone marrow transplant to separate effects on blood cells from vessel wall cells. These studies have produced apparently contradictory and surprising results. In particular, recent studies have identified a role for endogenous p53 in protection of VSMCs from apoptosis, trans-differentiation of bone marrow stromal cells into VSMCs in atherosclerosis, and altering the mode of cell death in the plaque.
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PMID:The role of p53 in atherosclerosis. 1692 77

Mild hypothermia, applied either during or soon after cerebral ischemia, has been shown to confer robust neuroprotection against brain injury in experimental stroke and in patients recovering from cardiac arrest. However, the mechanism underlying hypothermic neuroprotection is not completely understood. In this study, the effect of mild hypothermia on the induction of oxidative DNA damage, an early harmful event during post-ischemic reperfusion that triggers both necrotic and apoptotic cell death in the brain, was studied using the rat model of middle cerebral artery occlusion (MCAO) and reperfusion. Rats were subjected to 2-hr MCAO and reperfusion of various durations up to 3 days. Selective brain hypothermia (33 degrees C) was induced at the onset of ischemia and terminated at the beginning of reperfusion, and this significantly decreased infarct volume 72 hr later. Correlated with this protective effect, intraischemic mild hypothermia markedly attenuated the nuclear accumulations of several oxidative DNA lesions, including 8-oxodG, AP sites, and DNA single-strand breaks, after 2-hr MCAO. Consequently, harmful DNA damage-dependent signaling events, including NAD depletion, p53 activation, and mitochondrial translocation of PUMA and NOXA, were reduced during post-ischemic reperfusion in hypothermia-treated brains. These results suggest that the attenuation of oxidative DNA damage and DNA damage-triggered pro-death signaling events may be an important mechanism underlying the neuroprotective effect of mild hypothermia against ischemic brain injury.
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PMID:Mild hypothermia diminishes oxidative DNA damage and pro-death signaling events after cerebral ischemia: a mechanism for neuroprotection. 1712 18

Postmitotic neurons must survive for the entire life of the organism and be able to respond adaptively to adverse conditions of oxidative and genotoxic stress. Unrepaired DNA damage can trigger apoptosis of neurons which is typically mediated by the ataxia telangiectasia mutated (ATM)-p53 pathway. As in all mammalian cells, telomeres in neurons consist of TTAGGG DNA repeats and several associated proteins that form a nucleoprotein complex that prevents chromosome ends from being recognized as double strand breaks. Proteins that stabilize telomeres include TRF1 and TRF2, and proteins known to play important roles in DNA damage responses and DNA repair including ATM, Werner and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs). We have been performing studies of developing and adult neurons aimed at understanding the effects of global and telomere-directed DNA damage responses in neuronal plasticity and survival in the contexts of aging and neurodegenerative disorders. Deficits in specific DNA repair proteins, including DNA-PKcs and uracil DNA glycosylase (UDG), render neurons vulnerable to adverse conditions of relevance to the pathogenesis of neurodegenerative disorders such as Alzheimer's disease and stroke. Similarly, early postmitotic neurons with reduced telomerase activity exhibit accentuated responses to DNA damage and are prone to apoptosis demonstrating a pivotal role for telomere maintenance in both mitotic cells and postmitotic neurons. Our recent findings suggest key roles for TRF2 in regulating the differentiation and survival of neurons. TRF2 affects cell survival and differentiation by modulating DNA damage pathways, and gene expression. A better understanding of the molecular mechanisms by which neurons respond to global and telomere-specific DNA damage may reveal novel strategies for prevention and treatment of neurodegenerative disorders. Indeed, work in this and other laboratories has shown that dietary folic acid can protect neurons against Alzheimer's disease by keeping homocysteine levels low and thereby minimizing the misincorporation of uracil into DNA in neurons.
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PMID:DNA damage responses in neural cells: Focus on the telomere. 1720 36

We investigated the immunohistochemical alterations of the transcription nuclear factor kappa-B (NF-kappaB) and transcription factor p53 in the hippocampus after transient cerebral ischemia in gerbils. We also examined the effect of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin against the alterations of NF-kappaB, p53 and neuronal nuclei in the hippocampus after ischemia. Severe neuronal damage was observed in the hippocampal CA1 neurons 5 and 14 days after ischemia. In the present study, the increase of NF-kappaB immunoreactivity in glial cells and p53 immunoreactivity in neurons preceded neuronal damage in the hippocampal CA1 sector after ischemia. Thereafter, NF-kappaB immunoreactivity was induced highly in reactive astrocytes and microglia of the hippocampal CA1 sector where severe neuronal damage was observed. Our immunohistochemical study showed that pitavastatin prevented the alterations of NF-kappaB and p53 in the hippocampal CA1 sector 5 days after transient ischemia. Furthermore, our results with neuronal nuclei immunostaining indicate that pitavastatin dose-dependently prevented the neuronal cell death in the hippocampal CA1 sector 5 days after transient cerebral ischemia. These results suggest that the up-regulations of NF-kappaB in glia and p53 in neurons can cause neuronal cell death after ischemia. Our findings also support the hypothesis that NF-kappaB- and/or p53-mediated neuronal cell death is prevented through decreasing oxidative stress by pitavastatin. Thus, NF-kappaB and p53 may provide an attractive target for the development of novel therapeutic approaches for brain stroke.
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PMID:Immunohistochemical study on distribution of NF-kappaB and p53 in gerbil hippocampus after transient cerebral ischemia: effect of pitavastatin. 1722 97

The pathophysiology of cerebral ischemia involves multiple mechanisms including neuroinflammation mediated by activated microglia and infiltrating macrophages/monocytes. The present study employed a rat permanent middle cerebral artery occlusion (pMCAO) model to study effects of histone deacetylase (HDAC) inhibition on ischemia-induced brain infarction, neuroinflammation, gene expression, and neurological deficits. We found that post-pMCAO injections with HDAC inhibitors, valproic acid (VPA), sodium butyrate (SB), or trichostatin A (TSA), decreased brain infarct volume. Postinsult treatment with VPA or SB also suppressed microglial activation, reduced the number of microglia, and inhibited other inflammatory markers in the ischemic brain. The reduction in levels of acetylated histone H3 in the ischemic brain was prevented by treatment with VPA, SB, or TSA. Moreover, injections with HDAC inhibitors superinduced heat-shock protein 70 and blocked pMCAO-induced down-regulation of phospho-Akt, as well as ischemia-elicited up-regulation of p53, inducible nitric oxide synthase, and cyclooxygenase-2. The motor, sensory, and reflex performance of pMCAO rats was improved by VPA, SB, or TSA treatment. The beneficial effects of SB and VPA in reducing brain infarct volume and neurological deficits occurred when either drug was administrated at least 3 h after ischemic onset, and the behavioral improvement was long-lasting. Together, our results demonstrate robust neuroprotective effects of HDAC inhibitors against cerebral ischemia-induced brain injury. The neuroprotection probably involves multiple mechanisms including suppression of ischemia-induced cerebral inflammation. Given that there is no effective treatment for stroke, HDAC inhibitors, such as VPA, SB, and TSA, should be evaluated for their potential use for clinical trials in stroke patients.
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PMID:Histone deacetylase inhibitors exhibit anti-inflammatory and neuroprotective effects in a rat permanent ischemic model of stroke: multiple mechanisms of action. 1737 5

There is growing evidence that, because of the highly significant differences in gene activation/protein expression between animal models of stroke and stroke patients, the current treatment strategies based on animal stroke models have been unsuccessful. Therefore, it is imperative that the pathobiology of human stroke be studied. As a first step here, Western blotting and immunohistochemistry were employed to examine expression and tissue localization of key apoptotic proteins in infarct and peri-infarcted (penumbra) from grey and white matter in human postmortem tissue of 18 patients who died between 2 and 37 d after stroke caused by large vessel disease. The contralateral hemisphere was used as a control. JNK1, JNK2, and p53 were upregulated in the majority of samples, whereas Bcl-2, caspase-3, active caspase-3, phosphorylated p53 (p-p53), phosphorylated JNK1 (p-JNK1), and phosphorylated JNK2 (p-JNK2) were upregulated in approximately half of the samples. JNK1 expression was positively correlated with JNK2 expression in grey and white matter infarct and penumbra, whereas active caspase-3 levels were positively correlated with p-JNK2 levels in grey and white matter infarct. Using indirect immunoperoxidase staining of paraffin-embedded sections, active caspase-3 was found in infarcted neurons that co-localized with TUNEL-positive cells. p-JNK localization in the nuclei of TUNELpositive cells with the morphological appearance of neurons from infarct and penumbra was also demonstrated. The use of Kaplan Meier survival data demonstrated that the presence of Bcl-2 in penumbra of grey matter correlated significantly with shorter survival (p = 0.006). In conclusion, the present study has identified significantly altered expression of apoptotic proteins in human stroke tissue and shown that the presence of Bcl-2 in penumbra of grey matter has prognostic value. It is tempting to suggest that further studies of apoptotic proteins in human stroke may lead to identification of novel targets for drug discovery.
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PMID:Expression of signaling molecules associated with apoptosis in human ischemic stroke tissue. 1740 61

Protein kinase C (PKC) plays a critical role in diseases such as cancer, stroke, and cardiac ischemia and participates in a variety of signal transduction pathways including apoptosis, cell proliferation, and tumor suppression. Here, we demonstrate that PKCdelta is proteolytically cleaved and translocated to the nucleus in a time-dependent manner on treatment of desferroxamine (DFO), a hypoxia-mimetic agent. Specific knockdown of the endogenous PKCdelta by RNAi (sh-PKCdelta) or expression of the kinase-dead (Lys376Arg) mutant of PKCdelta (PKCdeltaKD) conferred modulation on the cellular adaptive responses to DFO treatment. Notably, the time-dependent accumulation of DFO-induced phosphorylation of Ser-139-H2AX (gamma-H2AX), a hallmark for DNA damage, was altered by sh-PKCdelta, and sh-PKCdelta completely abrogated the activation of caspase-3 in DFO-treated cells. Expression of Lys376Arg-mutated PKCdelta-enhanced green fluorescent protein (EGFP) appears to abrogate DFO/hypoxia-induced activation of endogenous PKCdelta and caspase-3, suggesting that PKCdeltaKD-EGFP serves a dominant-negative function. Additionally, DFO treatment also led to the activation of Chk1, p53, and Akt, where DFO-induced activation of p53, Chk1, and Akt occurred in both PKCdelta-dependent and -independent manners. In summary, these findings suggest that the activation of a PKCdelta-mediated signaling network is one of the critical contributing factors involved in fine-tuning of the DNA damage response to DFO treatment.
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PMID:Protein kinase Cdelta-dependent and -independent signaling in genotoxic response to treatment of desferroxamine, a hypoxia-mimetic agent. 1756 98

Lithium is a major drug used for the treatment of bipolar mood disorder and has recently been shown to have neuroprotective properties. In this study we investigated the neuroprotective effects of lithium in gerbils subjected to global cerebral ischemia, an animal model of stroke. The ischemia-induced exploratory behavior changes, measured by open field testing, were largely suppressed by lithium treatment for 7 days prior to ischemic onset. Similarly, memory impairments, measured by T-maze testing, were prevented by lithium pretreatment. This is believed to be the first report of lithium-induced protection against hyperactivity in a novel open field and memory impairment in a gerbil model of global ischemia. These behavioral benefits were associated with an increase in viable cells as measured by hematoxylin and eosin staining and a decrease in apoptotic TUNEL-positive cells in the CA1 hippocampal area of ischemic gerbils. Moreover, the lithium-induced neuroprotection was accompanied by down-regulation of pro-apoptotic p53 in the CA1 but up-regulation of anti-apoptotic Bcl-2 and heat shock protein 70 (HSP70) in the ischemic brain. These results underscore the ability of lithium to improve functional behavioral outcome in gerbil and rodent cerebral ischemic models and further indicate the potential therapeutic use of lithium in certain human stroke conditions.
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PMID:Lithium reduces ischemia-induced hippocampal CA1 damage and behavioral deficits in gerbils. 1802 86


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