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Anxiety-related disorders are complex illnesses that underlying molecular mechanisms need to be understood. Mitochondria stand as an important link between energy metabolism, oxidative stress, and anxiety. The nuclear factor, erythroid-derived 2,-like 1(Nrf1) is a member of the cap "n" collar subfamily of basic region leucine zipper transcription factors and plays the major role in regulating the adaptive response to oxidants and electrophiles within the cell. Here, we injected small interfering RNA (siRNA) targeting Nrf1 in dorsal third ventricle of adult male albino Wistar rats and subsequently examined the effect of this silencing on anxiety-related behavior. We also evaluated apoptotic markers and mitochondrial biogenesis factors, along with electron transport chain activity in three brain regions: hippocampus, amygdala, and prefrontal cortex. Our data revealed that in the group that received Nrf1-siRNA, anxiety-related behavior did not show any significant changes compared to the control group. Caspase-3 did not increase in Nrf1-siRNA-injected rats even though Bax/Bcl2 ratio markedly elevated in Nrf1-knockdown rats in all three mentioned regions compared to control rats. Also, Nrf1 silencing of complex I and II-III did not alter, generally. In addition, Nrf1-knockdown affected mitochondrial biogenesis markers. The level of peroxisome proliferator-activated receptor gamma coactivator-1α and cytochrome-c increased, which indicates a possible role for mitochondrial biogenesis in anxiety.

Context: Reactive oxygen species (ROS) are known to be one of the main causes of neurodegenerative disorders, and flavonoids play characteristic roles in a variety of biological activities, and specially are known to be antioxidant reagents., Objective: In this study, we investigated neuroprotective effects of digitoflavone to suppress H2O2 -induced cell death in neuron-like PC12 cells., Material and Methods: PC12 cells were pre-treated with digitoflavone for 2 h and then cells were exposed to H2O2 for 18 h. The cells' viability was evaluated by MTT assay. Rhodamine 123 staining was used for the determination of mitochondrial membrane potential (ΔΨm). The intracellular ROS aggregation was determined by using 2',7'-dichlorofluorescein diacetate. Also, the level of mitochondrial biogenesis factors was measured by western blot. The antioxidant capacity of digitoflavone was also determined by measuring reduced glutathione (GSH) level and catalase (CAT) activity quantification., Results: Digitoflavone significantly elevated cells' viability at concentrations of 10 and 20 µM. Also, digitoflavone attenuated intracellular level of ROS, and stabilized ΔΨm. Moreover, digitoflavone increased phosphorylation of AMP-activated protein kinase (AMPK) and, consequently, elevated mitochondrial biogenesis factors which were reduced after H2O2 exposure. We emphasized on the protective effect of digitoflavone through increasing mitochondrial biogenesis by specifically inhibiting AMPK. Antioxidant ability of digitoflavone was indicated by the elevation of GSH level and CAT activity., Conclusion: As a result, digitoflavone stabilize ΔΨm, enhanced cell viability through inducing mitochondrial biogenesis pathway, and increased antioxidant capacity of the cells which lead to better combating the oxidative stress.

Actinomycetes isolated from Iran soil habitats were tested for the capacity to produce compounds which can protect neurons from cell death generated by oxidative stress in NT2 neurons. Confirmation of our initial hit was accomplished via the determination of amyloid beta level using the enzyme-linked immunosorbent assay test. The most interesting amyloid beta formation inhibitor discovered in our study was a secondary metabolite which was produced by strain HM45. This bioactive strain was identified as a strain of Streptomyces antibioticus DSM 40234 using polyphasic approach. The strain HM45 was deposited in Deutsche Sammlung von Mikroorganismen und Zellkulturen as S. antibioticus DSM 41955 and University of Tehran Microorganisms Sollection as S. antibioticus UTMC 00105. This work is the first report on efficiency of an actinomycete metabolite in prohibition of neurons death caused by amyloid beta formation.

Increased oxidative stress is a widely accepted factor in the development and progression of Alzheimer's disease. Here, we introduce chitosan, an antioxidant oligosaccharide, as a protective agent against H(2)O(2)/FeSO(4)-induced cell death in the NT2 neural cell line. Chitosan not only protects the neurons against cell death, as measured by MTT and caspase-3 activity, but also decreases amyloid beta formation. NT2 neurons can be used to elucidate the relationship between oxidative stress and Abeta formation. We induced Abeta formation through oxidative stress in NT2 neurons and studied the effect of chitosan. We demonstrate that chitosan can be neuroprotective by suppressing Abeta formation. We further show that chitosan exerts its protective effect by up-regulation of HO-1, gamma-GCS, Hsp-70, and Nrf2, while it inhibits activation of caspase-3 and NF-kappaB. Chitosan or chitosan derivatives have potential value as neuroprotective agents, particularly with regard to oxidative stress.

Alzheimer's disease (AD) a progressive neurodegenerative disorder of later life, is characterized by brain deposition of amyloid beta-protein (Abeta) plaques, accumulation of intracellular neurofibrillatory tangles, synaptic loss and neuronal cell death. There is significant evidence that oxidative stress is a critical event in the pathogenesis of AD. In the present study Abeta formation was induced in NT2N neurons, one of the most appropriate cell line models in AD. Our results indicate that oxidative stress resulting from the treatment of H(2)O(2)/FeSO(4) and/or 4-hydroxy-2-noenal (HNE) can be inhibited in the presence of tBHQ, a known inducer of nuclear factor-erythroid 2 related factor 2 (Nrf2) in NT2N neurons and can therefore be used to elucidate the relationship between oxidative stress, Abeta formation and Nrf2. The role of Nrf2 was confirmed using retinoic acid as an inhibitor of Nrf2. It provides the first documentation that tBHQ not only protects the neurons against cell death but also decreases amyloid beta formation. Moreover, the results indicate that oxidative stress fosters Abeta formation in NT2N neurons, creating a vicious neurodegenerative loop., (Copyright (c) 2009 Elsevier Masson SAS. All rights reserved.)

To reduce the degradation pathway of rhIFN-gamma (recombinant human interferon-gamma), the susceptibility against oxidative stress during fermentation in Escherichia coli cells and in purification process were investigated. Fermentations of recombinant E. coli were performed at 5, 30 and 60% DO (dissolved oxygen) concentrations. The expressed rhIFN-gamma is purified in three-step chromatography processes with 99.9% purity under reducing and non-reducing conditions. Recombinant IFN-gamma production, carbonyl and dimeric contents and antiviral-specific activity of purified protein were monitored. The increase in carbonyl content was taken to be an indicator of protein oxidation. DO concentration did not show any noticeable effect on rhIFN-gamma production. During fermentation, the carbonyl-group content showed no significant increase at 5 and 30% DO but a 10-fold increase at 60% DO concentration was observed. The antiviral-specific activity of purified rhIFN-gamma was decreased 35 and 69% at 30 and 60% DO concentrations respectively. After the purification process, under non-reducing conditions, the activity of purified protein decreased to 30% of its original value. The degree of dimeric forms of protein was found to depend on the O2 concentration during fermentation and purification.

Abstract: Increased oxidative stress is a widely accepted factor in the development and progression of Alzheimer’s disease. Here we introduced alginate – an antioxidant oligosaccharide – as a protective agent on NT2 neural cell line against H2O2/FeSO4-induced cell death. Our results demonstrate that alginate not only protects the neurons against cell death, as measured by MTT test and caspase-3 activity determination, but also decreases amyloid β formation. In the present study we could induce Aβ formation through oxidative stress in NT2 neurons, one of the most appropriate cell line models in Alzheimer’s disease and provided the first documentation that alginate can be neuroprotective by suppressing Aβ formation. We further showed that alginate exerts its protective effect by up regulation of HO-1, γ-GCS, Hsp-70, Nrf2 and inhibiting caspase-3 and NF-κB. This study raises the possibility of developing alginate as a potential neuroprotective agent. [Copyright &y& Elsevier]