Overexpression of superoxide dismutase and catalase in immortalized neural cells: toxic effects of hydrogen peroxide

Neuroprotective Effect of Spice Oleoresins on Memory and Cognitive Impairment Associated with Scopolamine-Induced Alzheimer's Disease in Rats

Oleoresins are a mixture of volatile and nonvolatile components of concentrated forms of wholesome products. Even though there are several reports on the effect of spice or spice components on Alzheimer's disease, there are no studies on the effect of spice oleoresins. Hence, this study investigates the effect of pepper, chili, and turmeric oleoresins in Alzheimer's type of cognitive impairment in the rat model. The animals were grouped into six groups with six animals in each. They were (i) normal, (ii) scopolamine, (iii) scopolamine + pepper oleoresin, (iv) scopolamine + turmeric oleoresin, (v) scopolamine + chili oleoresin and (vi) scopolamine + donepezil for 13 days. Learning memory and acquisition memory were evaluated by a Morris water maze, and the locomotor activity was assessed by an actophotometer. Biochemical parameters such as AChE, malondialdehyde, reduced glutathione, glutathione peroxidase, superoxide dismutase, and catalase were studied. The brain histology was also studied. The scopolamine treatment significantly (P < 0.05) elevated the locomotor activity and escape latency time and reduced the time spent in the target quadrant, which was reversed in the case of the oleoresin treatment. Scopolamine-mediated changes in AChE, malondialdehyde, reduced glutathione, glutathione peroxidase, superoxide dismutase, and catalase were improved after the treatment with oleoresins. Among the three oleoresins, chili oleoresin were the most effective in behavioral activity, brain biomarkers, and recovery of antioxidant capacities when compared to the drug treatment. Chili and pepper oleoresins improved the protection against hippocampal damage. These oleoresins can be potent preventive/therapeutic agents against Alzheimer's disease. This study confirms the effect of spice oleoresins in Alzheimer's disease condition.

Design and Development of Novel Transdermal Nanoemulgel for Alzheimer’s Disease: Pharmacokinetic, Pharmacodynamic and Biochemical Investigations

Background:

Alzheimer’s disease is a chronic progressive neurodegenerative disorder associated with depletion of acetylcholine. Oral treatment with tacrine hydrochloride; a reversible inhibitor of acetylcholinesterase, finds limited use in Alzheimer’s disease due to frequent dosing, hepatotoxicity and extensive pre-systemic metabolism.

Objectives:

The objective of the study was to evaluate pharmacokinetic, pharmacodynamic, safety and stability profile of transdermal w/o nanoemulsion gel of tacrine hydrochloride and determine its relative bioavailability from transdermal nanogel in contrast to marketed capsule and conventional hydrogel.

Methods:

The optimized nanoemulsion gel NEGT4 (droplet size 156.4 ±0.48 nm, with poly dispersity index 0.36 ±0.4, permeation flux 6.172±2.94 µg/cm2/h across rat skin) was prepared by spontaneous emulsification followed by sonication. NEGT4 contained 7 mg of drug in 10% w/w distilled water, 30% w/w surfactant (Labrafil M) and cosurfactant (Transcutol P) mixture in ratio 1:4 and 60 % Capryol 90 as oily phase thickened with 98.9 mg ethyl cellulose (20 cps). In vivo studies were carried out on male Wistar rats following standard guidelines. Scopolamine was used to induce amnesia in rats which is a characteristic of Alzheimer’s disease. Various formulations were compared by performing pharmacokinetic, histopathological, behavioural and biochemical studies on rats. Stability studies on nanoemulsion gels were carried out in accordance with The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines.

Results:

Pharmacokinetic studies exhibited significantly greater extent of absorption from NEGT4 in comparison to capsule and hydrogel with a 2.18 and 5.26-fold increase respectively. Significant improvement in neurobehavioral parameters was observed with NEGT4 in scopolamine-induced amnesic rats. Biochemical assessment showed superior anti-amnesic activity of NEGT4 through augmentation of antioxidant enzymes, decreased lipid peroxidation and acetylcholinesterase activity. Low value of serum aminotransferase in rats treated with NEGT4 indicated the absence of hepatotoxicity. NEGT4 was found to be non-irritant and possessed a shelf life of 4.11 years.

Conclusion:

Developed nanoemulsion gel of tacrine hydrochloride was found to be safe, stable, and efficacious and has immense potential to be used in the therapy of Alzheimer’s disease.

Comparison of scopolamine-induced cognitive impairment responses in three different ICR stocks

Cognitive impairment responses are important research topics in the study of degenerative brain diseases as well as in understanding of human mental activities. To compare response to scopolamine (SPL)-induced cognitive impairment, we measured altered parameters for learning and memory ability, inflammatory response, oxidative stress, cholinergic dysfunction and neuronal cell damages, in Korl:ICR stock and two commercial breeder stocks (A:ICR and B:ICR) after relevant SPL exposure. In the water maze test, Korl:ICR showed no significant difference in SPL-induced learning and memory impairment compared to the two different ICRs, although escape latency was increased after SPL exposure. Although behavioral assessment using the manual avoidance test revealed reduced latency in all ICR mice after SPL treatment as compared to Vehicle, no differences were observed between the three ICR stocks. To determine cholinergic dysfunction induction by SPL exposure, activity of acetylcholinesterase (AChE) assessed in the three ICR stocks revealed no difference of acetylcholinesterase activity. Furthermore, low levels of superoxide dismutase (SOD) activity and high levels of inflammatory cytokines in SPL-treated group were maintained in all three ICR stocks, although some variations were observed between the SPLtreated groups. Neuronal cell damages induced by SPL showed similar response in all three ICR stocks, as assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, Nissl staining analysis and expression analyses of apoptosis-related proteins. Thus, the results of this study provide strong evidence that Korl:ICR is similar to the other two ICR. Stocks in response to learning and memory capacity.

Neuroprotective effect of Indian propolis in β-amyloid induced memory deficit: Impact on behavioral and biochemical parameters in rats

The study aimed at the investigation of neuroprotective activity of macerated ethanolic extract of Indian propolis (MEEP) against β-Amyloid 25-35 (Aβ_25-35) induced memory impairment in Alzheimer's disease. MEEP was administrated orally to Wistar rats at doses of 100, 200 and 300mg/kg. Behavioral performances were evaluated using morris water maze and radial arm maze. At the end of behavioral study, the brains were removed and antioxidant parameters and brain monoamines were estimated. Further acetylcholinesterase (AchE) inhibition and brain-derived neurotropic factor (BDNF) were evaluated. In addition hematological parameters and histopathological tests were also carried out. In behavioral models, MEEP significantly (P<0.05) reversed the cognitive impairment of β amyloid-induced rats. The antioxidant potential was significantly increased (P<0.05) after administration of MEEP. Malondialdehyde levels were significantly (P<0.01) decreased in brain homogenate after treatment with MEEP extract as compared with diseased control group (group III). MEEP showed dose-dependent AChE inhibition and increased the levels of brain monoamines (P<0.05) as compared with group III. MEEP improved memory deficits by increasing BDNF in plasma (P<0.05). The study concludes that MEEP has anti-Alzheimer potential in rats through multiple mechanisms and further studies are ongoing for fractionation and biological screening.

Human catalase: looking for complete identity

Catalases are well studied enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. The ubiquity of the enzyme and the availability of substrates made heme catalases the focus of many biochemical and molecular biology studies over 100 years. In human, this has been implicated in various physiological and pathological conditions. Advancement in proteomics revealed many of novel and previously unknown features of this mysterious enzyme, but some functional aspects are yet to be explained. Along with discussion on future research area, this mini-review compile the information available on the structure, function and mechanism of action of human catalase.

Glutathione peroxidase 1 deficiency attenuates allergen-induced airway inflammation by suppressing Th2 and Th17 cell development

Engagement of T cell receptor (TCR) triggers signaling pathways that mediate activation, proliferation, and differentiation of T lymphocytes. Such signaling events are mediated by reactive oxygen species (ROS), including hydrogen peroxide and lipid peroxides, both of which are reduced by glutathione peroxidase 1 (GPx1). We have now examined the role of GPx1 in the activation, differentiation, and functions of CD4(+) T helper (Th) cells. TCR stimulation increased the intracellular ROS concentration in Th cells in a time-dependent manner, and such TCR-induced ROS generation was found to promote cell proliferation. GPx1-deficient Th cells produced higher levels of intracellular ROS and interleukin-2 than wild-type Th cells and proliferated at a faster rate than did wild-type cells. Moreover, differentiation of GPx1-deficient Th cells was biased toward Th1, and Th17 cell development was also impeded by GPx1 depletion. Consistent with these findings, GPx1-null mice were protected from the development of ovalbumin-induced allergic asthma. Eosinophil infiltration, goblet cell hyperplasia, collagen deposition, and airway hyperresponsiveness were thus all attenuated in the lungs of GPx1-null mice. These data indicate that GPx1-dependent control of intracellular ROS accumulation is important not only for regulation of Th cell proliferation but for modulation of differentiation into Th1, Th2, and Th17 cells.

Progestins induce catalase activities in breast cancer cells through PRB isoform: correlation with cell growth inhibition

Reactive oxygen species (ROS) have been suggested to participate in tumor emergence due to their mitogenic and apoptotic signaling, and as contributors to DNA structural damage. Here we report that progesterone and various synthetic steroids with progestin potencies (norethisterone acetate, MPA, and Tibolone) counteract cell growth induced by hydrogen peroxide (H(2)O(2)), through a potent induction of catalase activities, in breast cancer cells and normal human epithelial breast cells. At physiological concentrations, progesterone and the pure progestin, Org2058, displayed the most potent H(2)O(2) detoxification ability suggesting its effect was characteristic of its progestin potency. We also report on the enhancement of catalase activities by progesterone receptor isoform B (PRB), as determined from experiments using antiprogestins and MDA-MB-231, cells engineered for the selective expression of progesterone receptor isoform A or B. The potent action of progesterone on catalase activities indicates its contribution to a beneficial role in breast cell homeostasis.

Transduction with the antioxidant enzyme catalase protects human T cells against oxidative stress

Patients with diseases characterized by chronic inflammation, caused by infection or cancer, have T cells and NK cells with impaired function. The underlying molecular mechanisms are diverse, but one of the major mediators in this immune suppression is oxidative stress caused by activated monocytes, granulocytes, or myeloid-derived suppressor cells. Reactive oxygen species can seriously hamper the efficacy of active immunotherapy and adoptive transfer of T and NK cells into patients. In this study, we have evaluated whether enhanced expression of the antioxidant enzyme catalase in human T cells can protect them against reactive oxygen species. Human CD4(+) and CD8(+) T cells retrovirally transduced with the catalase gene had increased intracellular expression and activity of catalase. Catalase transduction made CD4(+) T cells less sensitive to H(2)O(2)-induced loss-of-function, measured by their cytokine production and ability to expand in vitro following anti-CD3 stimulation. It also enhanced the resistance to oxidative stress-induced cell death after coculture with activated granulocytes, exposure to the oxidized lipid 4-hydroxynonenal, or H(2)O(2). Expression of catalase by CMV-specific CD8(+) T cells saved cells from cell death and improved their capacity to recognize CMV peptide-loaded target cells when exposed to H(2)O(2). These findings indicate that catalase-transduced T cells potentially are more efficacious for the immunotherapy of patients with advanced cancer or chronic viral infections.

Antifouling strategies for marine and riverine sensors

Traditionally, water quality has been monitored by sampling and lab based analysis. However, there are disadvantages associated with this method, for example, deterioration of samples with time, limited sampling points, limited temporal monitoring. This has provided impetus for the development of sensors which can be deployed from remote locations over extended deployment periods. However, a major limitation of these systems is their vulnerability to biofouling. This review outlines the research that has been carried out on strategies for the protection of marine and riverine sensors against fouling.

Rejuvenation of antioxidant system in central nervous system of aged rats by grape seed extract

Oxidative stress is considered as a major risk factor that contributes to age-related increase in lipid peroxidation and declined antioxidants in the central nervous system during aging. Grape seed extract, one of the bioflavonoid, is widely used for its medicinal properties. In the present study, we evaluated the role of grape seed extract on lipid peroxidation and antioxidant status in discrete regions of the central nervous system of young and aged rats. Male albino rats of Wistar strain were divided into four groups: Group I-control young rats, Group II-young rats treated with grape seed extract (100 mg/kg body weight) for 30 days, Group III-aged control rats and Group IV-aged rats supplemented with grape seed extract (100 mg/kg body weight) for 30 days. Age-associated increase in lipid peroxidation was observed in the spinal cord, cerebral cortex, striatum and the hippocampus regions of aged rats (Group III). Activities of antioxidant enzymes like superoxide dismutase, catalase, glutathione peroxidase and levels of non-enzymic antioxidants like reduced glutathione, Vitamin C and Vitamin E were found to be significantly decreased in all the brain regions studied in aged rats when compared to young rats. However, normalized lipid peroxidation and antioxidant defenses were reported in the grape seed extract-supplemented aged rats. These findings demonstrated that grape seed extract enhanced the antioxidant status and decreased the incidence of free radical-induced lipid peroxidation in the central nervous system of aged rats.

Characterization of an in vitro model of alphavirus infection of immature and mature neurons

Terminally differentiated, mature neurons are essential cells that are not easily regenerated. Neurotropic viruses, such as Sindbis virus (SV), cause encephalomyelitis through their ability to replicate in neurons. SV causes the death of immature neurons, while mature neurons can often survive infection. The lack of a reproducible and convenient neuronal cell culture system has hindered a detailed study of the differences in levels of virus replication between immature and mature neurons and the molecular events involved in virus clearance from mature neurons. We have characterized SV replication in immortalized CSM14.1 rat neuronal cells that can be differentiated into neurons. During differentiation, CSM14.1 cells ceased dividing, developed neuronal morphology, and expressed neuron-specific cell markers. SV infection of undifferentiated CSM14.1 cells was efficient and resulted in high levels of virus replication and cell death. SV infection of differentiated CSM14.1 cells was less efficient and resulted in the production of 10- to 100-fold less virus and cell survival. In undifferentiated cells, SV induced a rapid shutdown of cellular protein synthesis and pE2 was efficiently processed to E2 (ratio of E2 to pE2, 2.14). In differentiated cells, the SV-induced shutdown of cellular protein synthesis was transient and pE2 was the primary form of E2 in cells (ratio of E2 to pE2, 0.0426). We conclude that age-dependent restriction of virus replication is an intrinsic property of maturing neurons and that the CSM14.1 cell line is a convenient model system for investigating the interactions of alphaviruses with neurons at various stages of differentiation.

KR-31378 protects neurons from ischemia–reperfusion brain injury by attenuating lipid peroxidation and glutathione loss

Neuronal hyperexcitability and oxidative stress play critical roles in neuronal cell death in stroke. Therefore, we studied the effects of (2S,3S,4R)-N?-cyano-N-(6-amino-3,4-dihydro-3-hydroxy-2-methyl-2-dimethoxymethyl-2H-benzopyran-4-yl)-N'-benzylguanidine (KR-31378), possessing both antioxidant and K(+) channel-modulating activities, on brain ischemia-reperfusion injury models. Treatment with KR-31378 (30 mg/kg, i.v.) significantly reduced infarct area and edema by 24% and 36%, respectively, in rats subjected to 2 h of middle cerebral artery occlusion and 22 h of reperfusion with significant attenuation of elevated lipid peroxidation (99% of normal) and glutathione loss (60% of normal) in ischemic hemisphere. We further studied its neuroprotective mechanism in fetal rat primary mixed cortical culture. Incubation of cortical neurons with KR-31378 protected FeSO(4)-induced cell death in a concentration-dependent manner (IC(50)=12 microM). Its neuroprotective effect was neither mimicked by other K(+) channel openers nor abolished in the presence of ATP-dependent K(+) channel (K(ATP)) blockers, indicating that its effect was not related to K(+) channel opening activity. The mechanism of protection is rather attributable to the antioxidant property of KR-31378 since it suppressed the intracellular accumulation of reactive oxygen species and ensured lipid peroxidation by 120% and 80%, respectively, caused by FeSO(4). We further studied its effect on antioxidant defense, enzymatic and nonenzymatic systems. Treatment of neurons with FeSO(4) resulted in decrease of catalase (8% of control) and glutathione peroxidase (14% of control) activities, which were restored by KR-31378 treatment (70% and 57% of control, respectively). In addition, it attenuated the depletion of glutathione contents (60% of control) caused by FeSO(4). These results suggest that KR-31378 exerts a beneficial effect in focal ischemia, which may be attributed to its antioxidant property.

Decreased mitochondrial hydrogen peroxide release in transgenic Drosophila melanogaster expressing intramitochondrial catalase

The objective of this study was to develop strategies for manipulating oxidative stress transgenically in a multicellular organism. Ectopic catalase was introduced into the mitochondrial matrix, which is the main intracellular site of H2O2 formation and where catalase is normally absent. Transgenic Drosophila melanogaster were generated by microinjection of a P element construct, containing the genomic catalase sequence of Drosophila, with the mitochondrial leader sequence of ornithine aminotransferase inserted upstream of the coding region. Total catalase activities in whole-body homogenates of 10-day-old flies from four transgenic lines were approximately 30-160% higher than those from the parental and four vector-only control lines. Expression of catalase in the mitochondrial matrix was confirmed by immunoblotting and catalase activity assays. Mitochondrial release of H2O2 was decreased by approximately 90% in the transgenic lines when compared to levels in vector-only controls. This in vivo system provides a novel model for examining the functional significance of decreased mitochondrial H2O2 release.

Novel protein transfection of primary rat cortical neurons using an antibody that penetrates living cells

An Ab-based system to deliver functional proteins into neurons was developed using the murine mAb, mAb 3E10. This was achieved by covalently conjugating catalase to the Ab so that the conjugate retained high activity for the degradation of hydrogen peroxide. Three-dimensional fluorescence microscopy was used to demonstrate penetration of the Ab into the nucleus of living primary cortical neurons. The Ab conjugate localized in both the cytoplasm and nucleus. Retention of catalase activity after penetration and distribution of conjugate was demonstrated by reduction in cell death following exposure of treated neurons to hydrogen peroxide. These studies illustrate the potential of this method for the intracellular delivery of therapeutic proteins.

Protective effect of supplemental superoxide dismutase on survival of neuronal cells during starvation. Requirement for cytosolic distribution

There is evidence that raising cellular levels of Cu2+/Zn2+ superoxide dismutase (SOD1) can protect neurons from oxidative injury. We compared a novel method of elevating neuronal SOD activity using a recombinant hybrid protein composed of the atoxic neuronal binding domain of tetanus toxin (C fragment or TTC) and human SOD1 (hSOD1) with increasing cellular SOD levels through overexpression. Fetal murine cortical neurons or N18-RE-105 cells were incubated with the TTC-hSOD1 hybrid protein and compared to cells constitutively expressing hSOD1 for level of SOD activity, cellular localization of hSOD1, and capacity to survive glucose and pyruvate starvation. Cells incubated with TTC-hSOD1 showed a threefold increase in cellular SOD activity over control cells. This level of increase was comparable to fetal cortical neurons from transgenic mice constitutively expressing hSOD1 and transfected N18-RE-105 cells expressing a green fluorescent protein-hSOD1 fusion protein (GFP-hSOD1). Human SOD1 was distributed diffusely throughout the cytoplasm of the transgenic murine neurons and transfected N18-RE-105 cells. In contrast, cells incubated with TTC-hSOD1 showed hSOD1 localized to the cell surface and intra-cytoplasmic vesicles. The cells expressing hSOD1 showed enhanced survival in glucose- and pyruvate-free medium. Neither cortical neurons nor N18-RE-105 cells incubated in TTC-hSOD1 showed increased survival during starvation. Access to the site where toxic superoxides are generated or their targets may be necessary for the protective function of SOD1.

Dual mechanism of Fas-induced cell death in neuroglioma cells: a role for reactive oxygen species

ApoI/Fas belongs to the tumor necrosis factor receptor (TNFR) superfamily and mediates cell death in various cell types. A dual mode of Fas-triggered cell death has been reported depending on cell types used in the experiments. The present study was carried out to test the possible role of reactive oxygen species in this dual mechanism in neuroglioma cells. Anti-Fas antibody caused dose-dependent and time-dependent increase in cell death measured by lactate dehydrogenase (LDH) release in control neuroglioma cells and in cells that were transfected with catalase cDNA. However, cells transfected with copper/zinc superoxide dismutase (Cu/ZnSOD) cDNA showed marked attenuation of Fas-induced LDH release. Moreover, flow cytometry and confocal microscopy revealed that Fas-induced cell death in control cells occur mostly through an apoptotic process. This process was also completely abrogated in cells overexpressing catalase or copper/zinc superoxide dismutase (Cu/ZnSOD). Further experiments revealed that Fas-induced cell death was associated with increased formation of superoxide anions in control neuroglioma cells and in cells overexpressing catalase. These increases were significantly suppressed by Cu/ZnSOD overexpression. These data indicate that Fas-mediated cell death in neuroglioma cells occur, in part, through the production of reactive oxygen species (ROS). These observations also suggest that Fas-induced cell death in these cells occur through apoptosis and necrosis. Thus overexpression of Cu/ZnSOD caused the suppression of both types of Fas-induced cell death whereas catalase prevented apoptotic but not necrotic cell death. These observations are discussed in terms of their support for a role for both peroxides and superoxide radicals in Fas-induced cell death.

Maternal administration of superoxide dismutase and catalase in phenytoin teratogenicity

Embryonic bioactivation and formation of reactive oxygen species (ROS) are implicated in the mechanism of phenytoin teratogenicity. This in vivo study in pregnant CD-1 mice evaluated whether maternal administration of the antioxidative enzymes superoxide dismutase (SOD) and/or catalase conjugated with polyethylene glycol (PEG) could reduce phenytoin teratogenicity. Initial studies showed that pretreatment with PEG-SOD alone (0.5-20 KU/kg i.p. 4 or 8 h before phenytoin) actually increased the teratogenicity of phenytoin (65 mg/kg i.p. on gestational days [GD] 11 and 12, or 12 and 13) (p < .05), and appeared to increase embryonic protein oxidation. Combined pretreatment with PEG-SOD and PEG-catalase (10 KU/kg 8 or 12 h before phenytoin) was not embryo-protective, nor was PEG-catalase alone, although PEG-catalase alone reduced phenytoin-initiated protein oxidation in maternal liver (p < .05). However, time-response studies with PEG-catalase (10 KU/kg) on GDs 11, or 11 and 12, showed maximal 50-100% increases in embryonic activity sustained for 8-24 h after maternal injection (p < .05), and dose-response studies (10-50 KU/kg) at 8 h showed maximal respective 4-fold and 2-fold increases in maternal and embryonic activities with a 50 KU/kg dose (p < .05). In controls, embryonic catalase activity was about 4% of that in maternal liver, although with catalase treatment, enhanced embryonic activity was about 2% of enhanced maternal activity (p < .05). PEG-catalase pretreatment (10-50 KU/kg 8 h before phenytoin) also produced a dose-dependent inhibition of phenytoin teratogenicity, with maximal decreases in fetal cleft palates, resorptions and postpartum lethality at a 50 KU/kg dose (p < .05). This is the first evidence that maternal administration of PEG-catalase can substantially enhance embryonic activity, and that in vivo phenytoin teratogenicity can be modulated by antioxidative enzymes. Both the SOD-mediated enhancement of phenytoin teratogenicity, and the inhibition of phenytoin teratogenicity by catalase, indicate a critical role for ROS in the teratologic mechanism, and the teratologic importance of antioxidative balance.

Neurodegenerative disorders in humans: the role of glutathione in oxidative stress-mediated neuronal death

Oxidative stress has been implicated in both normal aging and in various neurodegenerative disorders and may be a common mechanism underlying various forms of cell death including necrosis, apoptosis, and excitotoxicity. In this review, we develop the hypothesis that oxidative stress-mediated neuronal loss may be initiated by a decline in the antioxidant molecule glutathione (GSH). GSH plays multiple roles in the nervous system including free radical scavenger, redox modulator of ionotropic receptor activity, and possible neurotransmitter. GSH depletion can enhance oxidative stress and may also increase the levels of excitotoxic molecules; both types of action can initiate cell death in distinct neuronal populations. Evidence for a role of oxidative stress and diminished GSH status is presented for Lou Gehrig's disease (ALS), Parkinson's disease, and Alzheimer's disease. Potential links to the Guamanian variant of these diseases (ALS-PD complex) are discussed. In context to the above, we provide a GSH-depletion model of neurodegenerative disorders, suggest experimental verifications of this model, and propose potential therapeutic approaches for preventing or halting these diseases.