Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P30044 (antioxidant enzyme)
 8,037 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glutathione peroxidase is an antioxidant enzyme that is involved in the control of cellular oxidative state. Recently, unregulated oxidative state has been implicated as detrimental to neural cell viability and involved in both acute and chronic neurodegeneration. In this study we have addressed the importance of a functional glutathione peroxidase in a mouse ischemia/reperfusion model. Two hours of focal cerebral ischemia followed by 24 h of reperfusion was induced via the intraluminal suture method. Infarct volume was increased three-fold in the glutathione peroxidase-1 (Gpx-1) -/- mouse compared with the wild-type mouse; this was mirrored by an increase in the level of apoptosis found at 24 h in the Gpx-1 -/- mouse compared with the wild-type mouse. Neuronal deficit scores correlated to the histologic data. We also found that activated caspase-3 expression is present at an earlier time point in the Gpx-1 -/- mice when compared with the wild-type mice, which suggests an enhanced susceptibility to apoptosis in the Gpx-1 -/- mouse. This is the first known report of such a dramatic increase, both temporally and in level of apoptosis in a mouse stroke model. Our results suggest that Gpx-1 plays an important regulatory role in the protection of neural cells in response to the extreme oxidative stress that is released during ischemia/reperfusion injury.
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PMID:Increased infarct size and exacerbated apoptosis in the glutathione peroxidase-1 (Gpx-1) knockout mouse brain in response to ischemia/reperfusion injury. 1157 47

Ginkgo biloba extract (EGb 761) is a standardized extract originating in traditional Chinese medicine. Ginkgo biloba dried leaves have been used for centuries to treat various neurological conditions. The constituents from the extract are likely to have synergistic effects that have been shown to be protective against oxidative stress injury. However, the cellular mechanisms of protection afforded by Ginkgo biloba are still unclear. The cascade leading to neuronal cell death in acute and chronic neurodegenerative conditions, such as cerebral ischemia and Alzheimer's disease, has been postulated to be mediated by free radical damage. We tested the hypothesis that the neuroprotective action of EGb 761 could be due partially to an induction of heme oxygenase I (HO1). We and others have previously reported that modulation of HO total activity may well have direct physiological implications in stroke and in Alzheimer's disease. Heme oxygenase acts as an antioxidant enzyme by degrading heme into iron, carbon monoxide, and biliverdin which is rapidly converted into bilirubin. Through the use of primary neuronal cultures, we demonstrated that EGb 761 induces HO1 in a dose-dependent manner (0, 10, 50, 100 and 500 microg/ml) and time-dependent manner with a maximal induction at 8 hr. We are proposing that several of the protective effects of EGb 761 in ischemia could be mediated through beneficial actions of heme degradation and its metabolites.
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PMID:Induction of heme oxygenase 1 by Ginkgo biloba in neuronal cultures and potential implications in ischemia. 1239 75

A direct involvement of the antioxidant enzyme NAD(P)H:quinone oxidoreductase (NQO1) in neuroprotection has not yet been shown. The aim of this study was to examine changes, localization and role of NQO1 after different neuronal injury paradigms. In primary cultures of rat cortex the activity of NQO1 was measured after treatment with ethylcholine aziridinium (AF64A; 40 micro m), inducing mainly apoptotic cell death, or oxygen-glucose deprivation (OGD; 120 min), which combines features of apoptotic and necrotic cell death. After treatment with AF64A a significant NQO1 activation started after 24 h. Sixty minutes after OGD a significant early induction of the enzyme was observed, followed by a second increase 24 h later. Enzyme activity was preferentially localized in glial cells in control and injured cultures, however, expression also occurred in injured neuronal cells. Inhibition of the NQO1 activity by dicoumarol, cibacron blue or chrysin (1-100 nM) protected the cells both after exposure to AF64A or OGD as assessed by the decreased release of lactate dehydrogenase. Comparable results were obtained in vivo using a mouse model of focal cerebral ischaemia. Dicoumarol treatment (30 nmol intracerebroventricular) reduced the infarct volume by 29% (p = 0.005) 48 h after the insult. After chemical induction of NQO1 activity by t-butylhydroquinone in vitro neuronal damage was exaggerated. Our data suggest that the activity of NQO1 is a deteriorating rather than a protective factor in neuronal cell death.
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PMID:Role of NAD(P)H:quinone oxidoreductase in the progression of neuronal cell death in vitro and following cerebral ischaemia in vivo. 1260 27

Prostaglandins (PGs) originate from the degradation of membranar arachidonic acid by cyclooxygenases (COX-1 and COX-2). The prostaglandin actions in the nervous system are multiple and have been suggested to play a significant role in neurodegenerative disorders. Some PGs have been reported to be toxic and, interestingly, the cyclopentenone PGs have been reported to be cytoprotective at low concentration and could play a significant role in neuronal plasticity. They have been shown to be protective against oxidative stress injury; however, the cellular mechanisms of protection afforded by these PGs are still unclear. It is postulated that the cascade leading to neuronal cell death in acute and chronic neurodegenerative conditions, such as cerebral ischemia and Alzheimer's disease, would be mediated by free radical damage. We tested the hypothesis that the neuroprotective action of cyclopentanone could be caused partially by an induction of heme oxygenase 1 (HO-1). We and others have previously reported that modulation of HO total activity may well have direct physiological implications in stroke and in Alzheimer's disease. HO acts as an antioxidant enzyme by degrading heme into iron, carbon monoxide, and biliverdin that is rapidly converted into bilirubin. Using mouse primary neuronal cultures, we demonstrated that PGs of the J series induce HO-1 in a dose-dependent manner (0, 0.5, 5, 10, 20, and 50 micro g/ml) and that PGJ(2) and dPGJ(2) were more potent than PGA(2), dPGA(2), PGD(2), and PGE(2). No significant effects were observed for HO-2 and actin expression. In regard to HO-3 expression found in rat, with its protein deducted sequence highly homologous to HO-2, no detection was observed in HO-2(-/-) mice, suggesting that HO-3 protein would not be present in mouse brain. We are proposing that several of the protective effects of PGJ(2) could be mediated through beneficial actions of heme degradation and its metabolites. The design of new mimetics based on the cyclopentenone structure could be very useful as neuroprotective agents and be tested in animal models of stroke and Alzheimer's disease.
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PMID:Regulation of heme oxygenase expression by cyclopentenone prostaglandins. 1270 76

The treatment of ischemic strokes is limited to the prevention of cerebrovascular risk factors and to the modulation of the coagulation cascade during the acute phase. A new therapeutic strategy could be to preventively protect the brain against noxious biological reactions induced by cerebral ischemia such as oxidative stress and inflammation to minimize their neurological consequences. Here, we show that a peroxisome proliferator-activated receptor (PPAR-alpha) activator, fenofibrate, protects against cerebral injury by anti-oxidant and anti-inflammatory mechanisms. A 14 d preventive treatment with fenofibrate reduces susceptibility to stroke in apolipoprotein E-deficient mice as well as decreases cerebral infarct volume in C57BL/6 wild-type mice. The neuroprotective effect of fenofibrate is completely absent in PPAR-alpha-deficient mice, suggesting that PPAR-alpha activation is involved as a mechanism of the protection against cerebral injury. Furthermore, this neuroprotective effect appears independently of any improvement in plasma lipids or glycemia and is associated with (1) an improvement in middle cerebral artery sensitivity to endothelium-dependent relaxation unrelated to an increase in nitric oxide synthase (NOS) type III expression, (2) a decrease in cerebral oxidative stress depending on the increase in numerous antioxidant enzyme activities, and (3) the prevention of ischemia-induced expression of vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 in cerebral vessels without any change in NOS II expression. These data demonstrate that PPAR-alpha could be a new pharmacological target to preventively reduce the deleterious neurological consequences of stroke in mice and suggest that PPAR-alpha activators could preventively decrease the severity of stroke in humans.
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PMID:Peroxisome proliferator-activated receptor-alpha activation as a mechanism of preventive neuroprotection induced by chronic fenofibrate treatment. 1286 11

Reactive oxygen species (ROS) are implicated in reperfusion injury after transient focal cerebral ischemia. The antioxidant enzyme Cu,Zn-superoxide dismutase (SOD) is one of the major means by which cells counteract the deleterious effects of ROS after ischemia. Recently, we reported that denatured Tat-SOD fusion protein is transduced into cells and skin tissue. Moreover, PEP-1 peptide, which has 21 amino acid residues, is a known carrier peptide that delivers full-length native proteins in vitro and in vivo. In the present study, we investigated the protective effects of PEP-1-SOD fusion protein after ischemic insult. A human SOD gene was fused with PEP-1 peptide in a bacterial expression vector to produce a genetic in-frame PEP-1-SOD fusion protein. The expressed and purified fusion proteins were efficiently transduced both in vitro and in vivo with a native protein structure. Immunohistochemical analysis revealed that PEP-1-SOD injected intraperitoneally (i.p.) into mice can have access into brain neurons. When i.p.-injected into gerbils, PEP-1-SOD fusion proteins prevented neuronal cell death in the hippocampus caused by transient forebrain ischemia. These results suggest that the biologically active intact forms of PEP-1-SOD provide a more efficient strategy for therapeutic delivery in various human diseases related to this antioxidant enzyme or to ROS, including stroke.
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PMID:In vivo protein transduction: biologically active intact pep-1-superoxide dismutase fusion protein efficiently protects against ischemic insult. 1547 17

Reactive oxygen species (ROS) are implicated in reperfusion injury after transient focal cerebral ischemia. The antioxidant enzyme, Cu,Zn-superoxide dismutase (SOD), is one of the major means by which cells counteract the deleterious effects of ROS after ischemia. Recently, we reported that when Tat-SOD fusion protein is transduced into pancreatic beta cells it protects the beta cells from destruction by relieving oxidative stress in ROS-implicated diabetes (Eum et al., 2004). In the present study, we investigated the protective effects of Tat-SOD fusion protein against neuronal cell death and ischemic insults. When Tat-SOD was added to the culture medium of neuronal cells, it rapidly entered the cells and protected them against paraquat-induced cell death. Immunohistochemical analysis revealed that Tat-SOD injected intraperitoneally (i.p.) into mice has access to various tissues including brain neurons. When i.p. injected into gerbils, Tat-SOD prevented neuronal cell death in the hippocampus in response to transient fore-brain ischemia. These results suggest that Tat-SOD provides a strategy for therapeutic delivery in various hu-man diseases, including stroke, related to this anti-oxidant enzyme or to ROS.
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PMID:Transduced Tat-SOD fusion protein protects against ischemic brain injury. 2044 45

Epidemiological studies indicate that the intake of flavonoids is inversely associated with risk of stroke, cardiovascular diseases and cancer. Isoliquiritigenin (ISL), a flavonoid constituent in the root of Glycyrrhiza glabra, is known to have vasorelaxant effect, antioxidant, anti-platelet, anti-tumor, anti-allergic, antiviral activities and estrogenic properties. However, there is no report on the effects of ISL in cerebral ischemia. Evidence demonstrate that the impaired energy metabolism and the excessive generation of reactive oxygen radicals (ROS) contribute to the brain injury associated with cerebral ischemia. In the present study, the protective effects of ISL were investigated in transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia-reperfusion injury in rats. Male Sprague-Dawley rats were divided into five groups: sham-operated group, vehicle-pretreated group, and three ISL-pretreated groups (5, 10 and 20 mg kg(-1), i.g.). ISL were administered once a day, for 7 days prior to ischemia. The rats were subjected to 2 h right MCAO via the intraluminal filament technique and 22 h reperfusion. Pretreatment with ISL significantly reduced the cerebral infarct volume and edema and produced significant reduction in neurological deficits. In this study, in order to clarify the mechanism of ISL's protection against cerebral ischemia damage, cerebral energy metabolism, brain Na+K+ATPase activity, malondialdehyde (MDA) content and antioxidant enzyme activities were measured. ISL pretreatment increased the brain ATP content, energy charge (EC) and total adenine nucleotides (TAN) in a dose-dependent manner. The brain Na+K+ATPase activity was protected significantly by pretreatment of ISL for 7 days. Pretreatment with ISL significantly inhibited the increases of brain MDA content and prevented the activities of brain superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) from declines caused by cerebral ischemia-reperfusion. All these findings indicate that ISL has the protective potential against cerebral ischemia injury and its protective effects may be due to the amelioration of cerebral energy metabolism and its antioxidant property.
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PMID:Protective effects of isoliquiritigenin in transient middle cerebral artery occlusion-induced focal cerebral ischemia in rats. 1645 97

1. The aim of this work was to study potential mechanisms participating in postischemic protection of selectively vulnerable CA1 neurons in the hippocampus. Experiments were focused on measuring changes in endogenous antioxidant enzyme activity. 2. Forebrain cerebral ischemia was induced in a rat by four-vessel occlusion. Ten minutes of ischemia induces so-called delayed neuronal death in selectively vulnerable CA1 region 3 days later. After 7 days of reperfusion, 71.6% of neurons succumb to neurodegeneration. When 5 min of ischemia was used as postconditioning, 2 days after 10 min of cerebral ischemia, delayed neuronal death in CA1 was almost completely (89.9%) prevented. 3. Searching for mechanisms of protection, we measured the activity of endogenous antioxidant enzymes. Activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were measured in the hippocampus, striatum and cortex by spectrophotometric methods after 10 min of ischemia used as the preconditioning. Two days after the preconditioning or the sham operation, second ischemia was induced for 5 min. We observed significant increase of total SOD activity in all studied regions of the brain 5 h after postconditioning (5 min of ischemia). SOD activity decreased to control values after 24 h. 4. In some experiments, we used intraperitoneal injections of norepinephrine (3.1 microM/kg) or 3-nitropropionic acid (20 mg/kg) as postconditioning, instead of ischemia. All three treatments resulted in significant increase of SOD activity, but norepinephrine was the most effective. The same effect as was seen for total SOD activity could be observed for CuZn-SOD as well as Mn-SOD activity. Similarly, considerable increase in the activity of catalase was detected 5 h after postconditioning (5 min of ischemia). It is interesting that the greatest changes were established in selectively vulnerable hippocampus and striatum. As in the case of SOD, the highest levels of CAT activity were induced by norepinephrine, while lower but significant increase in CAT activity was induced by 3-nitropropionic acid.5. Our results suggest that endogenous antioxidants SOD and CAT could play considerable neuroprotective role after postconditioning.
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PMID:The changes in endogenous antioxidant enzyme activity after postconditioning. 1674 74

Radix Angelica sinensis, known as Danggui in Chinese, has been used to treat cardiovascular and cerebrovascular diseases in Traditional Chinese Medicine for a long time. Modern phytochemical studies showed that Z-ligustilide (LIG) is the main lipophilic component of Danggui. In this study, we examined whether LIG could protect ischemia/reperfusion-induced brain injury by minimizing oxidative stress and anti-apoptosis. Transient forebrain cerebral ischemia (FCI) was induced by the bilateral common carotid arteries occlusion for 30 min. LIG was intraperitoneally injected to ICR mice at the beginning of reperfusion. As determined via 2,3,5-triphenyl tetrazolium chloride (TTC) staining at 24 h following ischemia, the infarction volume in the FCI mice treated without LIG (22.1 +/- 2.6%) was significantly higher than that in the FCI mice treated with 5 mg/kg (11.8 +/- 5.2%) and 20 mg/kg (2.60 +/- 1.5%) LIG (P < 0.05 or P < 0.01). LIG treatment significantly decreased the level of malondialdehyde (MDA) and increased the activities of the antioxidant enzyme glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) in the ischemic brain tissues (P < 0.05 or P < 0.01 vs. FCI group). In addition, LIG provided a great increase in Bcl-2 expression as well as a significant decrease in Bax and caspase-3 immunoreactivities in the ischemic cortex. The findings demonstrated that LIG could significantly protect the brain from damage induced by transient forebrain cerebral ischemia. The antioxidant and anti-apoptotic properties of LIG may contribute to the neuroprotective potential of LIG in cerebral ischemic damage.
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PMID:Neuroprotective role of Z-ligustilide against forebrain ischemic injury in ICR mice. 1680 12


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