Polypeptide from Chlamys farreri (PCF) is a novel marine polypeptide compound isolated from gonochoric Chinese scallop Chlamys farreri, this study we further investigate the mechanisms of PCF exerting its anti-apoptotic effect. The results indicated that PCF, ROS scavenger NAC and NF-κB inhibitor MG132 effectively inhibited UVB-induced HaCaT cells apoptosis. PCF (2.84 mM) showed potential ROS scavenging activities in a kinetic process. PCF (1.42-5.69 mM) dose-dependently increased the expressions of Cu, Zn-SOD, CAT and GPx meanwhile decreased the expressions of p-NF-κB/p65 and COX-2 in UVB-induced HaCaT cells. Additionally, pretreatment with NAC significantly declined the generation of ROS and the expression of p-NF-κB/p65. We concluded that ROS, NF-κB and COX-2 are involved in UVB-induced HaCaT cells apoptosis, PCF exerts its protective effects via scavenging ROS, increasing the expression of antioxidative enzymes and inhibition the activation of NF-κB and COX-2.

The present study was designed to explore the role of ontogenetic lead (Pb2+) exposure on a putative dopaminergic-nitrergic interaction in the nigrostriatal pathway. Pregnant Wistar rats were given tap water containing 250-ppm lead acetate, for the duration of pregnancy, with regular tap water (without Pb2+) being substituted at birth. Control rats were derived from dams that consumed tap water throughout pregnancy, and had no exposure to Pb2+ afterwards. At 12 weeks after birth in vivo microdialysis of the neostriatum was employed to demonstrate that maternal Pb2+ exposure was without effect on the baseline dopamine (DA) microdialysate concentration as well as amphetamine (AMPH, 1.0 mg/kg i.p.)-evoked release of striatal DA. Also, prenatal Pb2+ exposure did not enhance AMPH- and 7-nitroindazole (neuronal nitric oxide synthase inhibitor) (7-NI, 20 mg/kg i.p.)-induced hydroxyl radical (HO{radical dot}) formation in the striatum, as indicated by analysis of the salicylate spin-trap product 2,5-dihydroxybenzoic acid. However, in rats exposed prenatally to Pb2+, the facilitatory effect of 7-NI on DA exocytosis was attenuated. On the basis of the current study we conclude that maternal Pb2+ exposure distorts the dopaminergic-nitrergic interaction in the nigrostriatal pathway, but without involvement of reactive oxygen species (ROS).

Recently, the specific roles of integrin β4 in the signaling networks that drive pathological angiogenesis and tumor progression have been revealed. Our previous study showed that integrin β4 might be involved in neuron survival signal transduction. To further our study on the role of integrin β4 in the survival and apoptosis of primary cultured mouse neurons, we inhibited the expression of integrin β4 by its specific small interfering RNA. Viability of the cells remarkably declined, and neurons underwent apoptosis with down-regulation of integrin β4. Next, we investigated the effect of siRNA-mediated down-regulation of integrin β4 on the level of intracellular reactive oxygen species and the activities of NADPH oxidase and superoxide dismutase. The level of reactive oxygen species in the neurons was elevated significantly, the activities of manganese-dependent superoxide dismutase and copper/zinc-dependent superoxide dismutase were not altered, but the activity of NADPH oxidase was increased. Furthermore, inhibition of NADPH oxidase by its specific inhibitor dibenziodolium chloride attenuated the neuronal death induced by integrin β4 knockdown. The data suggest that integrin β4 is a key factor in neuron survival and apoptosis and indicate that this integrin subunit might perform its action through regulating NADPH oxidase and the level of reactive oxygen species in neuronal survival and apoptosis.

To understand the physiological function of glutaredoxin, a thiotransferase catalyzing the reduction of mixed disulfides of protein and glutathione, we generated a line of knockout mice deficient in the cytosolic glutaredoxin 1 (Grx1). To our surprise, mice deficient in Grx1 were not more susceptible to acute oxidative insults in models of heart and lung injury induced by ischemia/reperfusion and hyperoxia, respectively, suggesting that either changes in S-glutathionylation status of cytosolic proteins are not the major cause of such tissue injury or developmental adaptation in the Glrx1-knockout animals alters the response to oxidative insult. In contrast, mouse embryonic fibroblasts (MEFs) isolated from Grx1-deficient mice displayed an increased vulnerability to diquat and paraquat, but they were not more susceptible to cell death induced by hydrogen peroxide (H2O2) and diamide. A deficiency in Grx1 also sensitized MEFs to protein S-glutathionylation in response to H2O2 treatment and retarded deglutathionylation of the S-glutathionylated proteins, especially for a single prominent protein band. Additional experiments showed that MEFs lacking Grx1 were more tolerant to apoptosis induced by tumor necrosis factor αplus actinomycin D. These findings suggest that various oxidants may damage the cells via distinct mechanisms in which the action of Grx1 may or may not be protective and Grx1 may exert its function on specific target proteins.

Phytochemicals are recognized as playing an important role in cancer prevention by fruits and vegetables. The avocado is a widely grown and consumed fruit that is high in nutrients and low in calories, sodium, and fats. Studies have shown that phytochemicals extracted from the avocado fruit selectively induce cell cycle arrest, inhibit growth, and induce apoptosis in precancerous and cancer cell lines. Our recent studies indicate that phytochemicals extracted with chloroform from avocado fruits target multiple signaling pathways and increase intracellular reactive oxygen leading to apoptosis. This review summarizes the reported phytochemicals in avocado fruit and discusses their molecular mechanisms and targets. These studies suggest that individual and combinations of phytochemicals from the avocado fruit may offer an advantageous dietary strategy in cancer prevention.

5-HT2A/2C receptors are one of the most important in controlling basal ganglia outputs. In rodent models of Parkinson's disease (PD) blockade of these receptors increases locomotion and enhances the actions of dopamine (DA) replacement therapy. Moreover, previously we established that 5-HT 2A/2C antagonist attenuate DA D1 agonist mediated vacuous chewing movements (VCMs) which are considered as an animal representation of human dyskinesia. These findings implicate 5-HT neuronal phenotypes in basal ganglia pathology, and promote 5-HT2 antagonists as a rational treatment approach for dyskinesia that is prominent in most instances of PD replacement therapy. In the current study we determined whether ketanserin (KET) and/or amphetamine (AMPH) affected dopaminergic neurotranssmision in intact and fully DA-denervated rats. Moreover, we looked into extraneuronal content of HO. of the neostriatum after AMPH and/or KET injection, assessed by HPLC analysis of dihydroxybenzoic acids (2,3- and 2, 5-DHBA) - spin trap products of salicylate. Findings from the present study demonstrated that there are no substantial differences in extraneuronal HO. generation in the neostriatum between control and parkinsonian rats. KET did not affect DA release in the fully DA-denervated rat's neostriatum and also did not enhance HO. production. As 5-HT2A/2C receptor-mediated transmission might prove usefulness not only in addressing motor complications of PD patients (dyskinesia) but also in addressing non-motor problems such depression and/or L-DOPA evoked psychosis, the findings from the current study showed that the use of 5-HT2A/2C receptor antagonists in Parkinson's disease does not impend the neostriatal neuropil to be damaged by these drugs. We concluded that 5-HT2A/2C receptor antagonists may provide an attractive non-dopaminergic target for improving therapies for some basal ganglia disorders.

The cardiac toxicity of doxorubicin (DOX), a potent anticancer anthracycline antibiotic, is believed to be mediated through the generation of reactive oxygen species (ROS) in cardiomyocytes. This study aims to determine the function of cellular glutathione peroxidase (Gpx1), which is located in both mitochondria and cytosol, in defense against DOX-induced cardiomyopathy using a line of transgenic mice with cardiac overexpression of Gpx1. The Gpx1-overexpressing hearts were markedly more resistant than nontransgenic hearts to DOX-induced acute functional derangements, including impaired contractility and diastolic properties, decreased coronary flow rate, and reduced heart rate. In addition, DOX treatment impairs mitochondrial function of nontransgenic hearts as evident in a decreased rate of NAD-linked State 3 respiration, presumably a result of inactivation of complex I activity. This is associated with increases in the rates of NAD- and FAD-linked State 4 respiration and declines in P/O ratio, suggesting that the electron transfer and oxidative phosphorylation are uncoupled in these mitochondrial samples. These functional deficits of mitochondria could be largely prevented by Gpx1 overexpression. Taken together, these studies provide new evidence to further support the role of ROS, particularly H2O2 and/or fatty acid hydroperoxides, in causing contractile and mitochondrial dysfunction in mouse hearts acutely exposed to DOX.

2-Hydroxy-ethyl methacrylate (HEMA) is the major component released from resin-modified glass ionomer cements and dental adhesives. Human tissues mainly affected by HEMA are oral epithelium and dental pulp. We treated human gingival epithelial S-G cells and pulp fibroblasts (HPF) with various concentrations of HEMA, to evaluate its effects on cell growth, cell cycle progression, intracellular glutathione (GSH) level and reactive oxygen species (ROS) production. HEMA-induced growth inhibition in HPF and S-G cells in a dose-dependent manner, which may be partially explained by induction of cell cycle perturbation. G2/M phase arrest was noted after exposure of HPF to 5 and 10mM of HEMA, concomitant with glutathione depletion and ROS production. S-phase arrest occurred in S-G cells when treated with 2.5 and 5mM, while at 10mM a sub-G0/G1 peak was noted, indicating the potential induction of apoptosis. GSH depletion was marked in S-G cells only at concentrations of 5 and 10mM, but excessive ROS production was noted at concentration of 1mM and rose with dose increase between 1 and 5mM, then lessened at 10mM. This suggested that the increase of ROS in S-G cells was not mainly caused by GSH depletion. These results helped to define the mechanism of the cytotoxicity caused by HEMA.

Tobacco and alcohol are often co-abused. Nicotine can enhance alcoholic fatty liver, and CYP2A6 (CYP2A5 in mice), a major metabolism enzyme for nicotine, can be induced by alcohol. CYP2A5 knockout (cyp2a5−/−) mice and their littermates (cyp2a5+/+) were used to test whether CYP2A5 has an effect on nicotine-enhanced alcoholic fatty liver. The results showed that alcoholic fatty liver was enhanced by nicotine in cyp2a5+/+ mice but not in the cyp2a5−/− mice. Combination of ethanol and nicotine increased serum triglyceride in cyp2a5+/+ mice but not in the cyp2a5−/− mice. Cotinine, a major metabolite of nicotine, also enhanced alcoholic fatty liver, which was also observed in cyp2a5+/+ mice but not in the cyp2a5−/− mice. Nitrotyrosine and malondialdehyde (MDA), markers of oxidative/nitrosative stress, were induced by alcohol and were further increased by nicotine and cotinine in cyp2a5+/+ mice but not in the cyp2a5−/− mice. Reactive oxygen species (ROS) production during microsomal metabolism of nicotine and cotinine was increased in microsomes from cyp2a5+/+ mice but not in microsomes from cyp2a5−/− mice. These results suggest that nicotine enhances alcoholic fatty liver in a CYP2A5-dependent manner, which is related to ROS produced during the process of CYP2A5-dependent nicotine metabolism.

This article reviews recent studies on CYP2E1-mediated alcoholic liver injury, the induction of CYP2A5 by alcohol and the mechanism for this upregulation, especially the permissive role of CYP2E1 in the induction of CYP2A5 by alcohol and the CYP2E1-ROS-Nrf2 pathway, and protective effects of CYP2A5 against ethanol-induced oxidative liver injury. Ethanol can induce CYP2E1, an active generator of reactive oxygen species (ROS), and CYP2E1 is a contributing factor for alcoholinduced oxidative liver injury. CYP2A5, another isoform of cytochrome P450, can also be induced by ethanol. Chronic feeding of ethanol to wild type mice increased CYP2A5 catalytic activity, protein and mRNA levels as compared to pair-fed controls. This induction was blunted in CYP2E1 knockout (cyp2e1 -/- ) mice but was restored when human CYP2E1 was reintroduced and expressed in cyp2e1 -/- mice. Ethanol-induced CYP2E1 co-localized with CYP2A5 and preceded the elevation of CYP2A5. The antioxidants N-acetyl cysteine and vitamin C lowered the alcohol elevation of ROS and blunted the alcohol induction of CYP2A5, but not CYP2E1, suggesting ROS play a novel role in the crosstalk between CYP2E1 and CYP2A5. The antioxidants blocked the activation of Nrf2, a transcription factor known to upregulate expression of CYP2A5. When alcohol-induced liver injury was enhanced in Nrf2 knockout (Nrf2 -/- ) mice, alcohol elevation of CYP2A5 but not CYP2E1 was also lower in Nrf2 -/- mice. CYP2A5 knockout (cyp2a5 -/- ) mice exhibited an enhanced alcoholic liver injury compared with WT mice as indicated by serum ALT, steatosis and necroinflammation. Alcohol-induced hyperglycemia were observed in cyp2a5 -/- mice but not in WT mice.