Superoxide dismutase, aging, and degenerative disease

Unveiling the Detrimental Effect of Glipizide on Structure and Function of Catalase: Spectroscopic, Thermodynamics and Simulation Studies

Free radicals, products of oxidative processes, induce cellular damage linked to diseases like Parkinson's and diabetes due to increased reactive oxygen species (ROS) levels. Catalase, crucial for scavenging ROS, emerges as a therapeutic agent against ailments including atherosclerosis and tumor progression. Its primary function involves breaking down hydrogen peroxide into water and oxygen. Research on catalase-drug interactions reveals structural changes under specific conditions, affecting its activity and cellular antioxidant balance, highlighting its pivotal role in defending against oxidative stress-related diseases. Hence, targeting catalase is considered an effective strategy for controlling ROS-induced cellular damage. This study investigates the interaction between bovine liver catalase and glipizide using spectroscopic and computational methods. It also explores glipizide's effect on catalase activity. More than 20% inhibition of catalase enzymatic activity was recorded in the presence of 50 µM glipizide. To investigate the inhibition of catalase activity by glipizide, we performed a series of binding studies. Glipizide was found to form a complex with catalase with moderate affinity and binding constant in the range of 3.822 to 5.063 × 104 M-1. The binding was spontaneous and entropically favourable. The α-helical content of catalase increased from 24.04 to 29.53% upon glipizide complexation. Glipizide binding does not alter the local environment surrounding the tyrosine residues while a notable decrease in polarity around the tryptophan residues of catalase was recorded. Glipizide interacted with numerous active site residues of catalase including His361, Tyr357, Ala332, Asn147, Arg71, and Thr360. Molecular simulations revealed that the catalase-glipizide complex remained relatively stable in an aqueous environment. The binding of glipizide had a negligible effect on the secondary structure of catalase, and hydrogen bonds persisted consistently throughout the trajectory. These results could aid in the development of glipizide as a potent catalase inhibitor, potentially reducing the impact of reactive oxygen species (ROS) in the human body.

Impact of aging on copper isotopic composition in the murine brain

Aging is the main risk factor for Alzheimer's disease (AD). AD is linked to alterations in metal homeostasis and changes in stable metal isotopic composition can occur, possibly allowing the latter to serve as relevant biomarkers for potential AD diagnosis. Copper stable isotopes are used to investigate changes in Cu homeostasis associated with various diseases. Prior work has shown that in AD mouse models, the accumulation of 63Cu in the brain is associated with the disease's progression. However, our understanding of how the normal aging process influences the brain's isotopic composition of copper remains limited. In order to determine the utility and predictive power of Cu isotopes in AD diagnostics, we aim-in this study-to develop a baseline trajectory of Cu isotopic composition in the normally aging mouse brain. We determined the copper concentration and isotopic composition in brains of 30 healthy mice (WT) ranging in age from 6 to 12 mo, and further incorporate prior data obtained for 3-mo-old healthy mice; this range approximately equates to 20-50 yr in human equivalency. A significant 65Cu enrichment has been observed in the 12-mo-old mice compared to the youngest group, concomitant with an increase in Cu concentration with age. Meanwhile, literature data for brains of AD mice display an enrichment in 63Cu isotope compared to WT. It is acutely important that this baseline enrichment in 65Cu is fully constrained and normalized against if any coherent diagnostic observations regarding 63Cu enrichment as a biomarker for AD are to be developed.

N-Stearoylethanolamine Exerts Cardioprotective Effects in Old Rats

BACKGROUND

Aging is associated with the slowing down of metabolic processes, diminished physiological processes, changes in hormonal activity and increasing exposure to oxidative stress factors and chronic inflammation. The endocannabinoid system (ECS) is a major signaling network that plays a pro-homeostatic role in the central and peripheral organs of the human body. A class of minor lipids, N-acylethanolamines (NAEs), which do not activate cannabinoid receptors, except for anandamide, but can potentiate the action of endocannabinoids and have a wide spectrum of biological activity and significant adaptogenic potential, belongs to ECS. The results of different studies over the past decades have established the protective effect of NAE on many pathological conditions.

OBJECTIVE

This study aimed to investigate the cardioprotective effects of C18:0 NAE- N-stearoylethanolamine (NSE) in aged rats. In this study, we focused on investigating the effects of C18:0 NAE- N-stearoylethanolamine (NSE) on the intensity of oxidative/ nitrosative stress, antioxidant potential, lipoprotein profile and inflammation markers of blood plasma, phospholipid composition and age-related morphological changes of old rat heart tissues.

METHODS

The study was conducted on Sprague Dawley male laboratory rats. The three groups of rats were involved in the study design. The first group consisted of young rats aged 4 months (n=10). The second (n=10) and third (n=10) groups included old rats aged of 18 months. Rats from the third group were administered a per os aqueous suspension of NSE at a dose of 50 mg/kg of body weight daily for 10 days. All groups of rats were kept on a standard vivarium diet. The blood plasma, serum, and heart of rats were used for biochemical and histological analysis.

RESULTS

The cardioprotective effect of N-stearoylethanolamine in old rats was established, which was expressed in the normalization of the antioxidant system condition and the level of proinflammatory cytokines, positive modulation of blood plasma and lipoprotein profile, normalization of heart tissue lipid composition, and significant reduction in age-related myocardium morphological changes.

CONCLUSION

The revealed effects of N-stearoylethanolamine can become the basis for developing a new drug for use in complex therapy to improve the quality of life of older people.

Oxygen toxicity causes cyclic damage by destabilizing specific Fe-S cluster-containing protein complexes

Oxygen is toxic across all three domains of life. Yet, the underlying molecular mechanisms remain largely unknown. Here, we systematically investigate the major cellular pathways affected by excess molecular oxygen. We find that hyperoxia destabilizes a specific subset of Fe-S cluster (ISC)-containing proteins, resulting in impaired diphthamide synthesis, purine metabolism, nucleotide excision repair, and electron transport chain (ETC) function. Our findings translate to primary human lung cells and a mouse model of pulmonary oxygen toxicity. We demonstrate that the ETC is the most vulnerable to damage, resulting in decreased mitochondrial oxygen consumption. This leads to further tissue hyperoxia and cyclic damage of the additional ISC-containing pathways. In support of this model, primary ETC dysfunction in the Ndufs4 KO mouse model causes lung tissue hyperoxia and dramatically increases sensitivity to hyperoxia-mediated ISC damage. This work has important implications for hyperoxia pathologies, including bronchopulmonary dysplasia, ischemia-reperfusion injury, aging, and mitochondrial disorders.

Exogenous brassinosteroids promotes root growth, enhances stress tolerance, and increases yield in maize

Brassinosteroids (BRs) regulate of maize (Zea mays L.) growth, but the underlying molecular mechanism remains unclear. In this study, we used a multi-disciplinary approach to determine how BRs regulate maize morphology and physiology during development. Treatment with the BRs promoted primary root the elongation and growth during germination, and the early development of lateral roots. BRs treatment during the middle growth stage increased the levels of various stress resistance factors, and enhanced resistance to lodging, likely by protecting the plant against stem rot and sheath rot. BRs had no significant effect on plant height during late growth, but it increased leaf angle and photosynthetic efficiency, as well as yield and quality traits. Our findings increase our understanding of the regulatory effects of BR on maize root growth and development and the mechanism by which BR improves disease resistance, which could further the potential for using BR to improve maize yield.

Impacts on antioxidative enzymes and transcripts in darter (Etheostoma spp.) brains in the Grand River exposed to wastewater effluent

The Grand River watershed is the largest in southern Ontario and assimilates thirty wastewater treatment plants (WWTP) with varied degrees of treatment. Many WWTPs are unable to effectively eliminate several contaminants of emerging concern (CECs) from final effluent, leading to measurable concentrations in surface waters. Exposures to CECs have reported impacts on oxidative stress measured through antioxidative enzymes (SOD, CAT, GPX). This study focuses on the effects of WWTP effluent on four Etheostoma (Darter) species endemic to the Grand River, by investigating if increased antioxidative response markers are present in darter brains downstream from the effluent outfall compared to an upstream reference site relative to the Waterloo, ON WWTP across two separate years (Oct 2020 and Oct 2021). This was assessed using transcriptional and enzyme analysis of antioxidant enzymes and an enzyme involved in serotonin synthesis, tryptophan hydroxylase (tph). In fall 2020, significant differences in transcript markers were found between sites and sexes in GSD with SOD and CAT showing increased expression downstream, in JD with both sexes showing increased SOD downstream, and an interactive effect for tph in RBD. Changes in transcripts aligned with enzyme activity where interactive effects with sex-related differences were observed in fish collected fall 2020. In contrast, transcripts measured in fall 2021 were increased upstream compared to downstream species in RBD and GSD. This study additionally displayed yearly, species and sex differences in antioxidant responses. Continued investigation on the impacts of CECs in effluent in non-target species is required to better understand WWTP effluent impacts.

On the reactions of Cu(II/I)ATP complexes with methyl radicals

The Cu^I/IIATP react with methyl radicals to form methane and methanol, where Cu^IATP reacts with ^•CH₃ in a process that is surprisingly slow. The low-rate constant of this process is attributed to the significant rearrangement of the chelating ligand required for the transient's formation. These results were corroborated by DFT calculations of the relevant compounds.

Early responses in Penaeus vannamei during experimental infection with Enterocytozoon hepatopenaei (EHP) spores by injection and oral routes

Hepatopancreatic microsporidiosis caused by Enterocytozoon hepatopenaei (EHP) is associated with severe production losses in Penaeus vannamei farming. Early responses in P. vannamei experimentally infected with EHP was assessed in this study by feeding infected hepatopancreatic tissue and by injecting purified EHP spores (∼1 × 10⁵ Spores/shrimp). Immune responses to EHP infection were assessed in the haemolymph by analysing the total haemocyte count (THC), superoxide dismutase (SOD) activity, prophenoloxidase activity (proPO), respiratory burst activity (RBA), catalase activity (CAT), lysozyme activity (LYS) and Toll gene expression in hepatopancreas at 0, 6, 12, 24, 36, 48, 60 and 72 h post-infection (hpi). Experimental infection with EHP resulted in a significant (p < 0.05) reduction in the immune parameters such THC, CAT and LYS at 6, 24 and 24 hpi respectively while there was a significant increase (p < 0.05) in the levels of SOD, proPO and RBA at 6 hpi. The expression of the Toll gene was significantly upregulated (p < 0.05) after experimental infection with EHP from 6 hpi. These findings on immune responses in P. vannamei during EHP infection will assist in the development of suitable management measures to reduce the negative impacts of EHP in P. vannamei farming. This is the first report on early responses in P. vannamei during EHP infection.

Genetic repression of the antioxidant enzymes reduces the lifespan in Drosophila melanogaster

Aging is a biological process associated with gradual loss of function caused by cellular and molecular damages ultimately leading to mortality. Free radicals are implicated in oxidative damage which affects the longevity of organisms. Natural cellular defenses involving antioxidant enzymes delay or prevent oxidative damage and, therefore, influence the aging process and longevity has been shown in many species including Drosophila. We and others have shown that oxidative resistance is an important mechanism in the aging process in Drosophila. Therefore, we hypothesized that repressing endogenous antioxidant defenses shortens longevity in Drosophila. To study the influence of natural defense mechanisms against oxidative stress in aging, we have investigated the effect of genetic repression of the antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), on longevity in Drosophila using transgenic RNAi flies and in vivo inhibition of the enzymes with chemical inhibitors. RNAi lines of Drosophila viz., UAS-sod1-IR and UAS-cat-IR, are driven ubiquitously using Act5C-Gal4 and Tubulin-Gal4 to achieve the suppression of SOD1 and CAT activities, respectively. We show that genetic repression of SOD1 and CAT by RNAi in transgenic flies led to drastically reduced longevity (SOD1, 77%; CAT, 83%), presenting the evidence for the role of endogenous antioxidant defenses in lifespan extension in Drosophila. Further, our study shows that the enzyme inhibitors, diethyldithiocarbamate and 3-amino-1,2,4-triazole, although lower the enzyme activities in vivo in flies, but did not affect longevity, which could be attributed to the factors such as bioavailability and metabolism of the inhibitors and adaptive mechanisms involving de novo synthesis of the enzymes. Our study of genetic repression using transgenic RNAi provides experimental evidence that extended longevity is associated with endogenous antioxidant defenses and aging is correlated with oxidative stress resistance.

Silicone stressed response of crayfish (Procambarus clarkii) in antioxidant enzyme activity and related gene expression

Organosilicon has been widely used in various fields of industry and agriculture due to its excellent properties, such as high and low temperature resistance, flame retardant, insulation, radiation resistance and physiological inertia. However, organosilicon toxicity in aquatic animals is seldom known. In this research, two typical silicone or silane coupling agents (KH-560 (3-Glycidoxypropyltrimethoxysilane) and KH-570 (3-Methacryloxypropyltrimethoxysilane)) were used in a hydroponic experiment to evaluate the effects on survival rate, antioxidant response and gene expression in red swamp crayfish (Procambarus clarkii). Crayfishes were grown in black aquaculture boxes containing different concentrations (0, 10, 100 and 1000 mg L^-1) of KH-560 and KH-570 for 72 h, and then crayfish samples were harvested and separated into tissues of carapace, gill and muscle for analysis. The results showed that silicone significantly increased malondialdehyde (MDA) content in muscle by 17%-38% except for the treatment of 100 mg L^-1 KH-570, and reduced the survival rate of crayfish. Additionally, silicone KH-570 increased the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) by 15%-31%, 17%-35%, and 9%-46%, as well as the contents of ascorbate (AsA) and glutathione (GSH) by 19%-31%, and 23%-29% respectively, in muscle tissue, and similar results occurred in KH-560. In the carapace, however, SOD activity was significantly decreased at high concentrations level of both silicone treatments. Moreover, silicon (Si) content was higher in the abdominal muscle of crayfish after silicone treatment. Assay of gene expression showed an obvious increasing expression of antioxidant related genes (Sod1, Sod2, Cat1, Cat2, and Pod1, Pod2) under silicone stress. The above results suggested that silicone caused an obvious stress response in crayfish in both biochemical and molecular levels.

Utilizing an Animal Model to Identify Brain Neurodegeneration-Related Biomarkers in Aging

Glycine N-methyltransferase (GNMT) regulates S-adenosylmethionine (SAMe), a methyl donor in methylation. Over-expressed SAMe may cause neurogenic capacity reduction and memory impairment. GNMT knockout mice (GNMT-KO) was applied as an experimental model to evaluate its effect on neurons. In this study, proteins from brain tissues were studied using proteomic approaches, Haemotoxylin and Eosin staining, immunohistochemistry, Western blotting, and ingenuity pathway analysis. The expression of Receptor-interacting protein 1(RIPK1) and Caspase 3 were up-regulated and activity-dependent neuroprotective protein (ADNP) was down-regulated in GNMT-KO mice regardless of the age. Besides, proteins related to neuropathology, such as excitatory amino acid transporter 2, calcium/calmodulin-dependent protein kinase type II subunit alpha, and Cu-Zn superoxide dismutase were found only in the group of aged wild-type mice; 4-aminobutyrate amino transferase, limbic system-associated membrane protein, sodium- and chloride-dependent GABA transporter 3 and ProSAAS were found only in the group of young GNMT-KO mice and are related to function of neurons; serum albumin and Rho GDP dissociation inhibitor 1 were found only in the group of aged GNMT-KO mice and are connected to neurodegenerative disorders. With proteomic analyses, a pathway involving Gonadotropin-releasing hormone (GnRH) signal was found to be associated with aging. The GnRH pathway could provide additional information on the mechanism of aging and non-aging related neurodegeneration, and these protein markers may be served in developing future therapeutic treatments to ameliorate aging and prevent diseases.

Nannochloropsis spp. as Feed Additive for the Pacific White Shrimp: Effect on Midgut Microbiology, Thermal Shock Resistance and Immunology

This work aimed to evaluate Nannochloropsis spp. as feed additive in the diet of Pacific white shrimp for their effect on midgut microbiology, thermal shock resistance and immunological parameters. Initially, the digestibility of the microalgae meal was assessed, and the apparent digestibility coefficient (ADC) was determined. The ADC was, in general, high in lipids (78.88%) and eicosapentaenoic fatty acid (73.86%). Then, Nannochloropsis spp. were included in diets at four levels (0, 0.5, 1 and 2% inclusion). The shrimp were reared in 500 L clear water tanks containing 20 shrimp per tank with an initial weight of 6.05 ± 0.06 g and fed four times a day. Shrimp fed with supplemented diets containing Nannochloropsis spp. (0.5 and 2%) presented higher resistance to thermal shock when compared to the non-supplemented group (control). Shrimp fed with 1 and 2% of algae inclusion had a higher production of reactive oxygen species (ROS) when compared to other treatments. No statistical difference was observed in the immunological parameters and microbiology of the intestinal tract. Thus, the inclusion of Nannochloropsis spp. in shrimp diets at 0.5 and 2% levels increases resistance to thermal shock and ROS production in shrimp.

Stereological study and analysis of oxidative stress during renal aging in rats

PURPOSE

To evaluate renal histological changes by stereology and morphometry and analyze the main markers of oxidative stress in rats undergoing natural aging.

METHODS

Seventy two Wistar rats were divided into six groups of 12 rats each, which were euthanized at 3, 6, 9, 12, 18, and 24 months of age. Right kidney was stereologically and morphometrically analyzed to calculate the volumetric density (Vv[glom]), numerical density (Nv[glom]) and glomerular volume (Vol[glom]). Left kidney was used to determine the levels of nonprotein thiols, lipid peroxidation, and protein carbonylation, as well as the activities of superoxide-dismutase and catalase enzymes.

RESULTS

Both Vv[glom] and Nv[glom] values showed gradual decreases between groups. Activity of superoxide-dismutase was elevated at 24 months of age, and the levels of nonprotein thiols were higher in older animals. Greater catalase activity and protein carbonylation were observed in animals between 6 and 12 months of age but lessened in older rats. Lipid peroxidation decreased in the older groups.

CONCLUSIONS

Morphometric and stereological analyses revealed a gradual decrease in the volume and density of renal glomeruli during aging, as well as kidney atrophy. These findings related to oxidative stress clarify many changes occurring in kidney tissues during senescence in rats.

Growth and antioxidant response of juvenile oysters Crassostrea sikamea and Crassostrea corteziensis treated with Streptomyces strains

ABSTRACT The effect of three Streptomyces strains (N7, RL8 and V4) and a mixture of Bacillus (BMix) on the growth (Weight, Size) and superoxide dismutase activity (SOD) in hatchery-reared juvenile oysters Crassostrea corteziensis and Crassostrea sikamea was investigated to determine their probiotic potential. Microorganisms were added to culture water at 1×106 CFU/ml once a day during 30 days and all oysters fed daily a microalgae mix. Juveniles of C. sikamea treated with strains N7, RL8 and V4 had a significant weight gain compared to the control group. C. corteziensis juveniles treated with strains RL8 and BMix showed a significantly higher weight gain than the control group. No significant size increase was observed in any treated group for both oyster species. SOD activity significantly increased in C. sikamea treated with RL8 and with RL8, N7 and BMix in C. corteziensis. Streptomyces strains RL8 and N7 emerge as promising probiotic agents to cultivate C. sikamea and C. corteziensis and may also be useful to other molluscs and marine invertebrates .

Hybrid Compound SA-2 is Neuroprotective in Animal Models of Retinal Ganglion Cell Death

Purpose

Determine the toxicity, bioavailability in the retina, and neuroprotective effects of a hybrid antioxidant-nitric oxide donor compound SA-2 against oxidative stress-induced retinal ganglion cell (RGC) death in neurodegenerative animal models.

Methods

Optic nerve crush (ONC) and ischemia reperfusion (I/R) injury models were used in 12-week-old C57BL/6J mice to mimic conditions of glaucomatous neurodegeneration. Mice were treated intravitreally with either vehicle or SA-2. Retinal thickness was measured by spectral-domain optical coherence tomography (SD-OCT). The electroretinogram and pattern ERG (PERG) were used to assess retinal function. RGC survival was determined by counting RBPMS-positive RGCs and immunohistochemical analysis of superoxide dismutase 1 (SOD1) levels was carried out in the retina sections. Concentrations of SA-2 in the retina and choroid were determined using HPLC and MS. In addition, the direct effect of SA-2 treatment on RGC survival was assessed in ex vivo rat retinal explants under hypoxic (0.5% O2) conditions.

Results

Compound SA-2 did not induce any appreciable change in retinal thickness, or in a- or b-wave amplitude in naive animals. SA-2 was found to be bioavailable in both the retina and choroid after a single intravitreal injection (2% wt/vol). An increase in SOD1 levels in the retina of mice subjected to ONC and SA-2 treatment, suggests an enhancement in antioxidant activity. SA-2 provided significant (P < 0.05) RGC protection in all three of the tested RGC injury models in rodents. PERG amplitudes were significantly higher in both I/R and ONC mouse eyes following SA-2 treatment (P ≤ 0.001) in comparison with the vehicle and control groups.

Conclusions

Compound SA-2 was effective in preventing RGC death and loss of function in three different rodent models of acute RGC injury: ONC, I/R, and hypoxia.

Enhancing the activity and stability of Mn-superoxide dismutase by one-by-one ligation to catalase

Dismutation of superoxide by superoxide dismutase (SOD) generates hydrogen peroxide, which may be reduced to hydroxyl radical. The generated H₂O₂ during the catalysis can have an oxidative damage to SOD. Hydrogen peroxide decomposition by catalase (CAT) can help circumvent the problem. Mn-superoxide dismutase (herein referred to as SOD) and CAT are dimeric and tetrameric proteins, respectively. Herein, through intein-mediated in vivo subunit splicing, the C-terminus of the CAT subunit (CAT^S) has been specifically ligated to the N-terminus of the SOD subunit (SOD^S) with a peptide bond. Thus, the splicing product SOD&CAT combines the superoxide anion (•O₂^-) scavenging ability and the ability of decomposing H₂O₂. The in vivo subunit splicing has little effect on the secondary structures of the enzymes as confirmed by circular dichroism (CD) spectra. Fluorescence spectra showed that the splicing product SOD&CAT has a higher stability than SOD. In the splicing product SOD&CAT, the SOD subunits are in close proximity to the CAT subunits, facilitating immediate transfer of H₂O₂ between the enzymes and enabling efficient decomposition of H₂O₂. SOD&CAT exhibited a superoxide anion (•O₂^-) scavenging ability 244% higher than that of SOD and 46% higher than that of the mixed enzymes SOD+CAT.

Lactobacillus plantarum CQPC11 Isolated from Sichuan Pickled Cabbages Antagonizes d-galactose-Induced Oxidation and Aging in Mice

Chinese pickled cabbage is a traditional fermented food that contains abundant microbes produced during the process of fermentation. In this work, an in vivo animal study was conducted to investigate the effects of a newly isolated lactic acid bacterium (Lactobacillus plantarum CQPC11, LP-CQPC11) on d-galactose-induced oxidation and aging in mice. Analysis of the serum and tissue samples of these mice using molecular biology approaches showed that LP-CQPC11 suppressed the decrease in thymus, brain, heart, liver, spleen, and kidney indices caused by oxidation and aging. Furthermore, LP-CQPC11 increased the levels of SOD (superoxide dismutase), GSH-Px (glutathione peroxidase), and GSH (glutathione), whereas it reduced the levels of NO (nitric oxide) and MDA (malondialdehyde) in the serum, liver, and spleen of oxidation and aging mouse models. Pathological observation indicated that LP-CQPC11 alleviated the damage caused by oxidation and aging on the liver and spleen of mice. qPCR analysis indicated that LP-CQPC11 effectively upregulated the expression of nNOS (neuronal nitric oxide synthase), eNOS (endothelial nitric oxide synthase), Cu/Zn-SOD (cuprozinc-superoxide dismutase), Mn-SOD (manganese superoxide dismutase), CAT (catalase), HO-1 (heme oxygenase-1), Nrf2 (nuclear factor-erythroid 2 related factor 2), γ-GCS (γ-glutamylcysteine synthetase), and NQO1 (NAD(P)H dehydrogenase [quinone] 1), but downregulated the expression of iNOS (inducible nitric oxide synthase) in the mouse liver and spleen. Western blot analysis showed that LP-CQPC11 effectively upregulated SOD1 (Cu/Zn-SOD), SOD2 (Mn-SOD), CAT, GSH1 (c-glutamylcysteine synthetase), and GSH2 (glutathione synthetase) protein expression in mouse liver and spleen tissues. These findings suggest that LP-CQPC11 can effectively prevent d-galactose-induced oxidation and aging in mice, and the effect is even better than that of the commonly used Lactobacillus delbruechii subsp. bulgaricus (LDSB) and vitamin C in the industry. Thus, LP-CQPC11 may be potentially employed as a probiotic strain.

Inosine improves cognitive function and decreases aging-induced oxidative stress and neuroinflammation in aged female rats

In the present study, the effect of inosine was evaluated on learning and memory of 18 months old aged female rats. Inosine (50, 100 and 200 mg/kg; i.p.) was administered to separate groups of rats for 15 successive days. Donepezil (1 mg/kg; i.p.), an acetylcholinesterase inhibitor, was used as a standard drug. Behavioral models such as Morris water maze and elevated plus maze were used to evaluate the effect of drugs on learning and memory of rats. After behavioral studies, animals were killed and their brain was isolated and further processed for estimation of various biochemical parameters such as acetylcholinesterase activity, oxidative stress markers, proinflammatory marker and histological examinations. Inosine (100 and 200 mg/kg) significantly improved learning and memory of aged rats. Further, inosine significantly reduced lipid peroxidation and nitrite, and increased the levels of reduced glutathione and superoxide dismutase. However, no significant difference in AChEs activity was observed in inosine-treated rats as compared to aged control rats. TNF-α level was found to be ameliorated in aged rats by inosine. Histopathological evaluation showed that inosine-treated aged rats have less number of pyknotic neurons in hippocampal CA1 region as compared to aged control rats. In conclusion, inosine significantly improved learning and memory of aged female rats possibly through its antioxidant as well as anti-inflammatory effect and improvement of neuronal survival in the hippocampal CA1 region. However, additional studies are required to further explore the downstream signaling pathways involved in the neuroprotective effect of inosine in aged animals.

A Review of the Catalytic Mechanism of Human Manganese Superoxide Dismutase

Superoxide dismutases (SODs) are necessary antioxidant enzymes that protect cells from reactive oxygen species (ROS). Decreased levels of SODs or mutations that affect their catalytic activity have serious phenotypic consequences. SODs perform their bio-protective role by converting superoxide into oxygen and hydrogen peroxide by cyclic oxidation and reduction reactions with the active site metal. Mutations of SODs can cause cancer of the lung, colon, and lymphatic system, as well as neurodegenerative diseases such as Parkinson's disease and amyotrophic lateral sclerosis. While SODs have proven to be of significant biological importance since their discovery in 1968, the mechanistic nature of their catalytic function remains elusive. Extensive investigations with a multitude of approaches have tried to unveil the catalytic workings of SODs, but experimental limitations have impeded direct observations of the mechanism. Here, we focus on human MnSOD, the most significant enzyme in protecting against ROS in the human body. Human MnSOD resides in the mitochondrial matrix, the location of up to 90% of cellular ROS generation. We review the current knowledge of the MnSOD enzymatic mechanism and ongoing studies into solving the remaining mysteries.

Comparison of Antioxidative Effects of Insect Tea and Its Raw Tea (Kuding Tea) Polyphenols in Kunming Mice

Kudingcha is a traditional Chinese tea, and insect tea is a special drink produced by the metabolism of insect larvae using the raw Kuding tea. Insect tea polyphenols (ITP) and its raw tea (Kuding tea) polyphenols (KTP) are high-purity polyphenols extracted by centrifuge precipitation. The present study was designed to compare the antioxidative effects of insect tea polyphenols (ITP) and its raw tea (Kuding tea) polyphenols (KTP) on d-galactose-induced oxidation in Kunming (KM) mice. KM mice were treated with ITP (200 mg/kg) and KTP (200 mg/kg) by gavage, and vitamin C (VC, 200 mg/kg) was also used as a positive control by gavage. After determination in serum, liver and spleen, ITP-treated mice showed higher superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione (GSH) activities and lower nitric oxide (NO), malonaldehyde (MDA) activities than VC-treated mice, KTP-treated mice and untreated oxidation mice (control group). By H&E section observation, the mice induced by d-galactose-induced oxidation showed more changes than normal mice, and oxidative damage appeared in liver and spleen tissues; ITP, VC and KTP improved oxidative damage of liver and spleen tissues, and the effects of ITP were better than VC and KTP. Using quantitative polymerase chain reaction (qPCR) and western blot experiments, it was observed that ITP could increase the mRNA and protein expression of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), manganese superoxide dismutase (Mn-SOD), cupro/zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), heme oxygenase-1 (HO-1), nuclear factor erythroid 2 related factor 2 (Nrf2), gamma glutamylcysteine synthetase (γ-GCS), and NAD(P)H:quinone oxidoreductase 1 (NQO1) and reduce inducible nitric oxide synthase (iNOS) expression in liver and spleen tissues compared to the control group. These effects were stronger than for VC and KTP. Both ITP and KTP had good antioxidative effects, and after the transformation of insects, the effects of ITP were better than that of KTP and even better than VC. Thus, ITP can be used as an antioxidant and anti-ageing functional food.

The protective effect of Ginsenoside Rg1 on aging mouse pancreas damage induced by D-galactose

The protective effect and mechanism of Ginsenoside Rg1 on aging mouse pancreas damaged by D-galactose (D-gal)-induced was studied. Two-month-old male C57BL/6J mice were randomly divided into three groups of 10 mice per group. The D-gal group of mice received hypodermic injection of D-gal (120 mg/kg/day) for 42 days; the Rg1+D-gal group of mice receiving D-gal + intraperitoneal injection Rg1 (40 mg/kg/day) for 27 days from the 16th day of D-gal replication; and the naïve group that constituted the normal control mice receiving the same dose of saline instead of the drug. The related indicators were tested on the second day after modeling and administration. Fasting blood glucose (FBG), oral glucose tolerance test (OGTT) and fasting insulin level were measured by taking peripheral blood. Samples of pancreas were weighed and visceral index was calculated. Paraffin sections were prepared. H&E staining sections were produced to observe pancreatic tissue morphology. Immunohistochemical staining was used to observe advanced glycation end products (AGEs) and integral optical density (IOD) of stained positive tissue in pancreas. Ultrathin slices were used to observe ultrastructural change of pancreatic tissue. Frozen sections were prepared to test the relative optical density of positive cells that were stained by senescence-associated β-galactosidase (SA-β-gal) in pancreatic tissue. Superoxide dismutase (SOD), malonaldehyde (MDA) and total antioxidant capacity (T-AOC) were detected by preparing pancreas tissue homogenates. Compared with the control group, Rg1+D-gal mice had significantly decreased pancreatic wet weight and visceral index and significantly lower FBG; OGTT for 30 and 120 min. There was no significant difference of the blood sugar level between the groups. The area under the curve and the number and size of the nucleated cells within islet were markedly reduced. In addition, SA-β-gal-positive particles in pancreas tissue intracytoplasmic cells significantly decreased and relative optical density also reduced. The IOD of AGEs in pancreas tissue and MDA content decreased. SOD and T-AOC activity significantly increased. Ginsenoside Rg1 can be effective antagonistic structure and function of the pancreas injury induced by D-gal. The mechanism may be associated with reducing oxidative damage.

Hemato-immunological and biochemical parameters of silver catfish Rhamdia quelen immunized with live theronts of Ichthyophthirius multifiliis

This study investigated the immunization by intraperitoneal injection (i.p.) (assay I) and immersion bath (assay II) with live theronts of Ichthyophthirius multifillis in Rhamdia quelen and its influence on the hemato-immunological and biochemical parameters. Fish were divided in control (non immunized no challenged); non immunized and challenged with 12,000 theronts/fish; non immunized and challenged with 22,000 theronts/fish; immunized and challenged with 12,000 theronts/fish; immunized and challenged with 22,000 theronts/fish. Six days after challenge, either in the assay I or in the assay II the prevalence of I. multifillis in the gills was higher in non immunized fish (33.33% and 27.77%, respectively). In the assay I showed higher numbers of thrombocytes, leukocytes, lymphocytes, neutrophils and monocytes 20 days after injection and lower numbers after challenge. The immunoglobulin values were higher in fish non immunized. Fish immunized by immersion bath (assay II) showed greater values of catalase (CAT) in the liver (1245.49 U/mgprt) when compared to i.p. (198.79 U/mgprt). The levels of CAT in the liver of fish from the assay II were greater (1738.47 U/mgprt) 14 days after immunization than that observed 21 days after (1114.26 U/mgprt). The vaccination by i.p method showed influence on the hematological parameters. On the other hand, the immersion bath vaccination showed greater influence on the catalase activity in the liver. The results showed that new parameters like total protein, immunoglobulin and antioxidant enzymes could be considered in evaluating the host response to infection.

Study on the Dynamic Biological Characteristics of Sca-1(+) Hematopoietic Stem and Progenitor Cell Senescence

The researches in the dynamic changes of the progress of HSCs aging are very limited and necessary. In this study, male C57BL/6 mice were divided into 5 groups by age. We found that the superoxide damage of HSPCs started to increase from the middle age (6 months old), with notably reduced antioxidation ability. In accordance with that, the senescence of HSPCs also started from the middle age, since the self-renewal and differentiation ability remarkably decreased, and senescence-associated markers SA-β-GAL increased in the 6-month-old and the older groups. Interestingly, the telomere length and telomerase activity increased to a certain degree in the 6-month-old group. It suggested an intrinsic spontaneous ability of HSPCs against aging. It may provide a theoretical and experimental foundation for better understanding the senescence progress of HSPCs. And the dynamic biological characteristics of HSPCs senescence may also contribute to the clinical optimal time for antiaging drug intervention.

The paradoxical role of thioredoxin on oxidative stress and aging

In spite of intensive study, there is still controversy about the free radical or oxidative stress theory of aging, particularly in mammals. Our laboratory has conducted the first detailed studies on the role of thioredoxin (Trx) in the cytosol (Trx1) and in mitochondria (Trx2) on oxidative stress and aging using unique mouse models either overexpressing or down-regulating Trx1 or Trx2. The results generated from our lab and others indicate that: (1) oxidative stress and subsequent changes in signaling pathways could have different pathophysiological impacts at different stages of life; (2) changes in redox-sensitive signaling controlled by levels of oxidative stress and redox state could play more important roles in pathophysiology than accumulation of oxidative damage; (3) changes in oxidative stress and redox state in different cellular compartments (cytosol, mitochondria, or nucleus) could play different roles in pathophysiology during aging, and their combined effects show more impact on aging than changes in either oxidative stress or redox state alone; and (4) the roles of oxidative stress and redox state could have different pathophysiological consequences in different organs/tissues/cells or pathophysiological conditions. To critically test the role of oxidative stress on aging and investigate changes in redox-sensitive signaling pathways, further study is required.

Anthocyanin induces apoptosis of DU-145 cells in vitro and inhibits xenograft growth of prostate cancer

PURPOSE

To investigate the effects of anthocyanins extracted from black soybean, which have antioxidant activity, on apoptosis in vitro (in hormone refractory prostate cancer cells) and on tumor growth in vivo (in athymic nude mouse xenograft model).

MATERIALS AND METHODS

The growth and viability of DU-145 cells treated with anthocyanins were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and apoptosis was assessed by DNA laddering. Immunoblotting was conducted to evaluate differences in the expressions of p53, Bax, Bcl, androgen receptor (AR), and prostate specific antigen (PSA). To study the inhibitory effects of anthocyanins on tumor growth in vivo, DU-145 tumor xenografts were established in athymic nude mice. The anthocyanin group was treated with daily oral anthocyanin (8 mg/kg) for 14 weeks. After 2 weeks of treatment, DU-145 cells (2×10⁶) were inoculated subcutaneously into the right flank to establish tumor xenografts. Tumor dimensions were measured twice a week using calipers and volumes were calculated.

RESULTS

Anthocyanin treatment of DU-145 cells resulted in 1) significant increase in apoptosis in a dose-dependent manner, 2) significant decrease in p53 and Bcl-2 expressions (with increased Bax expression), and 3) significant decrease in PSA and AR expressions. In the xenograft model, anthocyanin treatment significantly inhibit tumor growth.

CONCLUSION

This study suggests that anthocyanins from black soybean inhibit the progression of prostate cancer in vitro and in a xenograft model.

Effects of diabetes on oxidative and nitrosative stress in kidney mitochondria from aged rats

Diabetes mellitus (DM) is characterized by chronic hyperglycemia resulting from defects in the secretion and/or action of insulin. Diabetic nephropathy (DN) develops in diabetic patients and is characterized by a progressive deterioration of renal function. The mitochondrial electron transport chain (ETC) produces most of the reactive oxygen species (ROS) that are involved in diabetic nephropathy. Due to the high incidence of DM in the elderly, the aim of this study was to evaluate oxidative and nitrosative stress in kidney mitochondria from aged rats. We evaluated lipid peroxidation (LPO), nitric oxide (NO(•)) production, S-nitrosylation profiles, glutathione levels, and glutathione reductase and aconitase activities under streptozotocin (STZ)-induced experimental diabetes in kidney mitochondria from aged rats. The results showed an increase in LPO, NO(•) production, and S-nitrosylated proteins in rats with STZ-induced diabetes. A decrease in glutathione (GSH) levels and glutathione reductase (GR) and aconitase activities in the rats that received the STZ-induced diabetes treatment was also observed, when compared with the age-related controls. The data suggest that oxidative and nitrosative stresses promote mitochondrial oxidative dysfunction in the more advanced age rat kidney in STZ-induced diabetes.

Age-related decrease in the mitochondrial sirtuin deacetylase Sirt3 expression associated with ROS accumulation in the auditory cortex of the mimetic aging rat model

Age-related dysfunction of the central auditory system, also known as central presbycusis, can affect speech perception and sound localization. Understanding the pathogenesis of central presbycusis will help to develop novel approaches to prevent or treat this disease. In this study, the mechanisms of central presbycusis were investigated using a mimetic aging rat model induced by chronic injection of D-galactose (D-Gal). We showed that malondialdehyde (MDA) levels were increased and manganese superoxide dismutase (SOD2) activity was reduced in the auditory cortex in natural aging and D-Gal-induced mimetic aging rats. Furthermore, mitochondrial DNA (mtDNA) 4834 bp deletion, abnormal ultrastructure and cell apoptosis in the auditory cortex were also found in natural aging and D-Gal mimetic aging rats. Sirt3, a mitochondrial NAD+-dependent deacetylase, has been shown to play a crucial role in controlling cellular reactive oxygen species (ROS) homeostasis. However, the role of Sirt3 in the pathogenesis of age-related central auditory cortex deterioration is still unclear. Here, we showed that decreased Sirt3 expression might be associated with increased SOD2 acetylation, which negatively regulates SOD2 activity. Oxidative stress accumulation was likely the result of low SOD2 activity and a decline in ROS clearance. Our findings indicate that Sirt3 might play an essential role, via the mediation of SOD2, in central presbycusis and that manipulation of Sirt3 expression might provide a new approach to combat aging and oxidative stress-related diseases.

Absence of superoxide dismutase activity causes nuclear DNA fragmentation during the aging process

Superoxide dismutases (SOD) serve as an important antioxidant defense mechanism in aerobic organisms, and deletion of these genes shortens the replicative life span in the budding yeast Saccharomyces cerevisiae. Even though involvement of superoxide dismutase enzymes in ROS scavenging and the aging process has been studied extensively in different organisms, analyses of DNA damages has not been performed for replicatively old superoxide dismutase deficient cells. In this study, we investigated the roles of SOD1, SOD2 and CCS1 genes in preserving genomic integrity in replicatively old yeast cells using the single cell comet assay. We observed that extend of DNA damage was not significantly different among the young cells of wild type, sod1Δ and sod2Δ strains. However, ccs1Δ mutants showed a 60% higher amount of DNA damage in the young stage compared to that of the wild type cells. The aging process increased the DNA damage rates 3-fold in the wild type and more than 5-fold in sod1Δ, sod2Δ, and ccs1Δ mutant cells. Furthermore, ROS levels of these strains showed a similar pattern to their DNA damage contents. Thus, our results confirm that cells accumulate DNA damages during the aging process and reveal that superoxide dismutase enzymes play a substantial role in preserving the genomic integrity in this process.

Growth hormone alters the glutathione S-transferase and mitochondrial thioredoxin systems in long-living Ames dwarf mice

Ames dwarf mice are deficient in growth hormone (GH), prolactin, and thyroid-stimulating hormone and live significantly longer than their wild-type (WT) siblings. The lack of GH is associated with stress resistance and increased longevity. However, the mechanism underlying GH's actions on cellular stress defense have yet to be elucidated. In this study, WT or Ames dwarf mice were treated with saline or GH (WT saline, Dwarf saline, and Dwarf GH) two times daily for 7 days. The body and liver weights of Ames dwarf mice were significantly increased after 7 days of GH administration. Mitochondrial protein levels of the glutathione S-transferase (GST) isozymes, K1 and M4 (GSTK1 and GSTM4), were significantly higher in dwarf mice (Dwarf saline) when compared with WT mice (WT saline). GH administration downregulated the expression of GSTK1 proteins in dwarf mice. We further investigated GST activity from liver lysates using different substrates. Substrate-specific GST activity (bromosulfophthalein, dichloronitrobenzene, and 4-hydrox-ynonenal) was significantly reduced in GH-treated dwarf mice. In addition, GH treatment attenuated the activity of thioredoxin and glutaredoxin in liver mitochondria of Ames mice. Importantly, GH treatment suppressed Trx2 and TrxR2 mRNA expression. These data indicate that GH has a role in stress resistance by altering the functional capacity of the GST system through the regulation of specific GST family members in long-living Ames dwarf mice. It also affects the regulation of thioredoxin and glutaredoxin, factors that regulate posttranslational modification of proteins and redox balance, thereby further influencing stress resistance.

Astrocyte-neuron co-culture on microchips based on the model of SOD mutation to mimic ALS

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease. ALS is believed to be a non-cell autonomous condition, as other cell types, including astrocytes, have been implicated in disease pathogenesis. Hence, to facilitate the development of therapeutics against ALS, it is crucial to better understand the interactions between astrocytes and neural cells. Furthermore, cell culture assays are needed that mimic the complexity of cell to cell communication at the same time as they provide control over the different microenvironmental parameters. Here, we aim to validate a previously developed microfluidic system for an astrocyte-neuron cell culture platform, in which astrocytes have been genetically modified to overexpress either a human wild-type (WT) or a mutated form of the super oxide dismutase enzyme 1 (SOD1). Cortical neural cells were co-cultured with infected astrocytes and studied for up to two weeks. Using our microfluidic device that prevents direct cell to cell contact, we could evaluate neural cell response in the vicinity of astrocytes. We showed that neuronal cell density was reduced by about 45% when neurons were co-cultured with SOD-mutant astrocytes. Moreover, we demonstrated that SOD-WT overexpressing astrocytes reduced oxidative stress on cortical neurons that were in close metabolic contact. In contrast, cortical neurons in metabolic contact with SOD-mutant astrocytes lost their synapsin protein expression after severe glutamate treatment, an indication of the toxicity potentiating effect of the SOD-mutant enzyme.

Thioredoxin, oxidative stress, cancer and aging

The Free Radical or Oxidative Stress Theory of Aging is one of the most popular theories in aging research and has been extensively studied over the past several decades. However, recent evidence using transgenic/knockout mice that overexpress or down-regulate antioxidant enzymes challenge the veracity of this theory since the animals show no increase or decrease in lifespan. These results seriously call into question the role of oxidative damage/stress in the aging process in mammals. Therefore, the theory requires significant modifications if we are to understand the relationship between aging and the regulation of oxidative stress. Our laboratory has been examining the impacts of thioredoxins (Trxs), in the cytosol and mitochondria, on aging and age-related diseases. Our data from mice that are either up-regulating or down-regulating Trx in different cellular compartments, that is, the cytosol or mitochondria, could shed some light on the role of oxidative stress and its pathophysiological effects. The results generated from our lab and others may indicate that: 1) changes in oxidative stress and the redox state in the cytosol, mitochondria or nucleus might play different roles in the aging process; 2) the role of oxidative stress and redox state could have different pathophysiological consequences in different tissues/cells, for example, mitotic vs. post-mitotic; 3) oxidative stress could have different pathophysiological impacts in young and old animals; and 4) the pathophysiological roles of oxidative stress and redox state could be controlled through changes in redox-sensitive signaling, which could have more diverse effects on pathophysiology than the accumulation of oxidative damage to various molecules. To critically test the role of oxidative stress on aging and age-related diseases, further study is required using animal models that regulate oxidative stress levels differently in each cellular compartment, each tissue/organ, and/or at different stages of life (young, middle and old) to change redox sensitive signaling pathways.

ROS in aging Caenorhabditis elegans: damage or signaling?

Many insights into the mechanisms and signaling pathways underlying aging have resulted from research on the nematode Caenorhabditis elegans. In this paper, we discuss the recent findings that emerged using this model organism concerning the role of reactive oxygen species (ROS) in the aging process. The accrual of oxidative stress and damage has been the predominant mechanistic explanation for the process of aging for many years, but reviewing the recent studies in C. elegans calls this theory into question. Thus, it becomes more and more evident that ROS are not merely toxic byproducts of the oxidative metabolism. Rather it seems more likely that tightly controlled concentrations of ROS and fluctuations in redox potential are important mediators of signaling processes. We therefore discuss some theories that explain how redox signaling may be involved in aging and provide some examples of ROS functions and signaling in C. elegans metabolism. To understand the role of ROS and the redox status in physiology, stress response, development, and aging, there is a rising need for accurate and reversible in vivo detection. Therefore, we comment on some methods of ROS and redox detection with emphasis on the implementation of genetically encoded biosensors in C. elegans.

Methionine sulfoxide reductase A: Structure, function and role in ocular pathology

Methionine is a highly susceptible amino acid that can be oxidized to S and R diastereomeric forms of methionine sulfoxide by many of the reactive oxygen species generated in biological systems. Methionine sulfoxide reductases (Msrs) are thioredoxin-linked enzymes involved in the enzymatic conversion of methionine sulfoxide to methionine. Although MsrA and MsrB have the same function of methionine reduction, they differ in substrate specificity, active site composition, subcellular localization, and evolution. MsrA has been localized in different ocular regions and is abundantly expressed in the retina and in retinal pigment epithelial (RPE) cells. MsrA protects cells from oxidative stress. Overexpression of MsrA increases resistance to cell death, while silencing or knocking down MsrA decreases cell survival; events that are mediated by mitochondria. MsrA participates in protein-protein interaction with several other cellular proteins. The interaction of MsrA with α-crystallins is of utmost importance given the known functions of the latter in protein folding, neuroprotection, and cell survival. Oxidation of methionine residues in α-crystallins results in loss of chaperone function and possibly its antiapoptotic properties. Recent work from our laboratory has shown that MsrA is co-localized with αA and αB crystallins in the retinal samples of patients with age-related macular degeneration. We have also found that chemically induced hypoxia regulates the expression of MsrA and MsrB2 in human RPE cells. Thus, MsrA is a critical enzyme that participates in cell and tissue protection, and its interaction with other proteins/growth factors may provide a target for therapeutic strategies to prevent degenerative diseases.

A potential biochemical mechanism underlying the influence of sterol deprivation stress on Caenorhabditis elegans longevity

To investigate the biochemical mechanism underlying the effect of sterol deprivation on longevity in Caenorhabditis elegans, we treated parent worms (P0) with 25-azacoprostane (Aza), which inhibits sitosterol-to-cholesterol conversion, and measured mean lifespan (MLS) in F2 worms. At 25 μM (∼EC(50)), Aza reduced total body sterol by 82.5%, confirming sterol depletion. Aza (25 μM) treatment of wild-type (N2) C. elegans grown in sitosterol (5 μg/ml) reduced MLS by 35%. Similar results were obtained for the stress-related mutants daf-16(mu86) and gas-1(fc21). Unexpectedly, Aza had essentially no effect on MLS in the stress-resistant daf-2(e1370) or mitochondrial complex II mutant mev-1(kn1) strains, indicating that Aza may target both insulin/IGF-1 signaling (IIS) and mitochondrial complex II. Aza increased reactive oxygen species (ROS) levels 2.7-fold in N2 worms, but did not affect ROS production by mev-1(kn1), suggesting a direct link between Aza treatment and mitochondrial ROS production. Moreover, expression of the stress-response transcription factor SKN-1 was decreased in amphid neurons by Aza and that of DAF-28 was increased when DAF-6 was involved, contributing to lifespan reduction.

Minimal peroxide exposure of neuronal cells induces multifaceted adaptive responses

Oxidative exposure of cells occurs naturally and may be associated with cellular damage and dysfunction. Protracted low level oxidative exposure can induce accumulated cell disruption, affecting multiple cellular functions. Accumulated oxidative exposure has also been proposed as one of the potential hallmarks of the physiological/pathophysiological aging process. We investigated the multifactorial effects of long-term minimal peroxide exposure upon SH-SY5Y neural cells to understand how they respond to the continued presence of oxidative stressors. We show that minimal protracted oxidative stresses induce complex molecular and physiological alterations in cell functionality. Upon chronic exposure to minimal doses of hydrogen peroxide, SH-SY5Y cells displayed a multifactorial response to the stressor. To fully appreciate the peroxide-mediated cellular effects, we assessed these adaptive effects at the genomic, proteomic and cellular signal processing level. Combined analyses of these multiple levels of investigation revealed a complex cellular adaptive response to the protracted peroxide exposure. This adaptive response involved changes in cytoskeletal structure, energy metabolic shifts towards glycolysis and selective alterations in transmembrane receptor activity. Our analyses of the global responses to chronic stressor exposure, at multiple biological levels, revealed a viable neural phenotype in-part reminiscent of aged or damaged neural tissue. Our paradigm indicates how cellular physiology can subtly change in different contexts and potentially aid the appreciation of stress response adaptations.

Regulation of mRNA translation as a conserved mechanism of longevity control

Appropriate regulation of mRNA translation is essential for growth and survival and the pathways that regulate mRNA translation have been highly conserved throughout eukaryotic evolution. Translation is controlled by a complex set of mechanisms acting at multiple levels, ranging from global protein synthesis to individual mRNAs. Recently, several mutations that perturb regulation of mRNA translation have also been found to increase longevity in three model organisms: the buddingyeast Saccharomyces cerevisiae, the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Many of these translation control factors can be mapped to a single pathway downstream of the nutrient responsive target of rapamycin (TOR) kinase. In this chapter, we will review the data suggesting that mRNA translation is an evolutionarily conserved modifier of longevity and discuss potential mechanisms by which mRNA translation could influence aging and age-associated disease in different species.