Search

Increasing evidence supports the role of oxidative stress in cancer development. Ultraviolet (UV) irradiation is one of the major sources of oxidative stress through the generation of reactive oxygen species (ROS). Besides the physiological function of ROS in cellular homeostasis, accumulating reports suggest that ROS are involved in all stages of multistep cancer development. In order to investigate the involvement of oxidative damage into the mechanisms of tumour progression, we used a parallel proteomic approach to analyse the protein expression profile and to identify oxidatively modified proteins in human papillomavirus (HPV)-transformed keratinocytes (HK-168 cells) upon ultraviolet B (UVB) exposure. The HK-168 cells were obtained from normal human epidermal keratinocytes transfected with the whole genome of the high-risk HPV type 16, unanimously recognized as an etiological agent of cervical carcinoma. Because of its year-long latency, this tumour offers a convenient model to study the role of environmental concurring agents in the multistep malignant progression. By the protein expression profile, we identified 21 proteins that showed different expression levels in HK-168 cells treated with UVB in comparison with untreated cells. Focusing on the oxidative modifications occurring at the protein level, we identified five proteins that showed elevated protein carbonyls levels: alpha-enolase, heat shock protein 75, annexin 2, elongation factor Tu and elongation factor gamma. Our results indicate that UVB-induced oxidative stress perturbs the normal redox balance and shifts HPV-transformed keratinocytes into a state in which the carbonylation of specific proteins is systematically induced. We suggest that UVB-induced modulation of protein expression combined with oxidative modification lead to protein dysfunction that might contribute to the malignant progression of transformed cells.

This poster has been prepared to be presented in the FENS 2020 Virtual Forum (11-15 July)., {"references":["Bathina S, Das UN. Brain-derived neurotrophic factor and its clinical Implications. Arch Med Sci. 2015;11(6):1164-1178.","Butterfield DA, Halliwell B. Oxidative stress, dysfunctional glucose metabolism and Alzheimer disease. Nat Rev Neurosci. 2019;20(3):148- 160.","Wang JX, Rogers LM, Gross EZ, et al. Targeted enhancement of cortical-hippocampal brain networks and associative memory. Science (80- ). 2014;345(6200):1054-1057","Wei CW, Sun Y, Chen N, et al. Interaction of oxidative stress and BDNF on executive dysfunction in patients with chronic schizophrenia. Psychoneuroendocrinology. 2020;111:104473.","Bramham CR, Messaoudi E. BDNF function in adult synaptic plasticity: The synaptic consolidation hypothesis. Prog Neurobiol. 2005;76(2):99- 125.","Schrag M, Mueller C, Zabel M, et al. Oxidative stress in blood in Alzheimer's disease and mild cognitive impairment: A meta-analysis. Neurobiol Dis. 2013;59:100-110.","Zhao X, Li Y, Tian Q, et al. Repetitive transcranial magnetic stimulation increases serum brain-derived neurotrophic factor and decreases interleukin-1β and tumor necrosis factor-α in elderly patients with refractory depression. J Int Med Res. 2019;47(5):1848-1855."]}

Alzheimer's disease (AD) is a chronic and slowly progressing neurodegenerative disorder which has become a major health concern worldwide. The literature has shown that oxidative stress is one of the most important risk factors behind the cause of AD. Oxidative stress often leads to the production of Reactive Oxygen Species (ROS). D-Galactose, a physiological nutrient and reducing sugar, non-enzymatically reacts with amines of amino acids in proteins and peptides to form Advanced Glycation End products which activate its receptors coupled to Biochemical pathways that stimulate free radical production and induces mitochondrial dysfunction which damages the neuron intracellularly. High dosage of D-Galactose also suppresses the expression of nerve growth factors and its associated protein which results in the degeneration of nerve cells and reduction of acetylcholine levels in brain regions. This article put forwards the advantages of using Lactic Acid Bacteria (Probiotics) possessing anti-oxidant properties and which produces Acetyl Choline against D-Galactose induced Alzheimer's disease. Keywords: D-Galactose, Alzheimer's disease, Adjuvant therapy, Probiotics. Introduction Alzheimer's disease (AD) is one of the most prevalent neurode­generative disorder in the aged people across the world. Till date worldwide, nearly 44 million people have been affected by Alzheimer's related dementia and it is estimated that more than 4 mil­lion and 5.3 million individuals have Alzheimer's disease in In­dia and the United States, respectively [1,2]. It is projected that more than 13.5 million individuals will be having AD by the year 2050 [3]. AD is clinically characterized on the basis of the brain pathological hallmarks such as dystrophic neuritis, neurofibrillary tangles and β amyloid plaques derived from the amyloid precursor proteins [4]. Neurotoxicity of amyloid plaques not only increases oxidative stress which causes low-grade inflammation by activating the nuclear factor-kappa B (NF-κB) signalling pathway but also, accelerates the aging process which further leads to the genera­tion of reactive oxygen species (ROS) [5-7]. ROS is involved in mitochondrial dysfunction and damage of neuronal membranes, proteins, lipids, and nucleic acids [8]. Prolonged supplementation of D-Galactose induces oxidative stress followed by mitochondrial dysfunction and intracellular damage of neurons, accelerating aging, and influencing age-related cognitive decline in experimental animals [9]. D-Galactose Induced Alzheimer's Disease D-Galactose induces aging-inducible oxidative stress in vivo, which resembles the natural aging process in mice [10, 11]. D-Galactose is metabolized to galactose-1-phosphate at a normal concentration by D-galactokinase or galactose-1-phosphate uridyl-transferase, but not at high levels. Instead, at increased concentration, D-galactose is converted to galactitol, which accumulates in cells and then induces osmotic stress and generates reactive oxygen species (ROS) which induces mitochondrial dysfunction and is the major cause of intracellular damage [12]. D-Galactose also reacts with the free amines of amino acids in peptides and proteins forming advanced glycation end-products (AGE) [13]. High dosage of D-Galactose also suppresses the expression of nerve growth factors and its associate protein resulting in the degeneration of nerve cells and reduction of acetylcholine levels in brain regions (Figure 1). ROS activate inflammatory signaling molecules, such as the phosphatidylinositol 3-kinase (PI3K), nuclear factor-kappa B (NF-kB), Janus kinase (JAK) and mitogen-activated protein kinases (MAPK). It also induces the expression of tumor necrosis factor-alpha, interleukin-1b (IL-1b) and IL-6 [14]. D-Galactose increases replicative senescence markers p16 expression and telomere shortening but reduces doublecortin (DCX) expression [15]. Therefore, D-galactose continuously stimulates low-grade inflammation, which is associated with the acceleration of aging. Lactic Acid Bacteria (Probiotics) and D-Galactose Induced Alzheimer's Disease Lactic acid bacteria (LAB) are gram-positive, acid-tolerant and generally non-sporulating bacteria. The LAB is found in various food stuff like cheese, yogurt, and among the vagina and gastrointestinal microbiota. Most of LAB, Lactobacilli and Bifidobacteria, are microorganisms deemed beneficiall to us since they produce lactic acid as a major end product. Therefore, they are considered as safe products, due to their ubiquitous appearance in food and their contribution to the healthy microbiota [16]. Lactobacillus is a gram-positive facultative anaerobic or microaerophilic rod-shaped bacteria. They also possesss various properties like anticancer, antioxidant, antidiabetic, antiobesity, and antihyperlipidemic effects [17]. Recent studies have found that the L. plantarum versus pentosus showed a protective effect against memory deficit in AD-induced mice by D-Galactose and scopolamine [13,18]. Further, another study reported that L. Plantarum NDC75017 improves the learning and memory ability in aging rats [19]. Previous reports proved that strong antioxidants increases the Na+, K+-ATPases activities by decreasing AChE (Acetyl cholinesterase) levels and improves the cognition by enhancing cholinergic transmission [20]. Lactobacillus plantarum MTCC1325 strain has the ability to produce Acetylcholine Neurotransmitter via both externally and internally pathway [21] and this strain also possess potential antioxidant activity. Chronic injection of D-Galactose induces memory impairment, neurodegeneration and oxidative damage in mice [22]. L. plantarum MTCC 1325 has the ability to produce the neurotransmitter viz. Acetylcholine [23] and also possesses potential antioxidant activity. Biochemically, it was well established that AD has been related to a significant decrease in the brain neurotransmitter ACh [24] and oxidative stress, eventually leading to imbalance production and detoxification of ROS, which is considered to be the important factor in the development of AD. AD-model rats showed a significant decline in total body weight, organ index, hair loss and skin elasticity[25]. Chronic administration of D-Galactose caused significant decline in spatial memory and reduced gross behaviorall activity which suggests impairment of memory [9]. From the comparative studies conducted for 60 days in rats, it was evident that chronic administration of L. plantarum MTCC1325 for 60 days showed significant improvement and recovery from AD. There was significant improvement in the activities of the membrane transport ATPases system in the selected brain regions of AD-induced group as well. Further, it was revealed that L. Plantarum MTCC1325 protects the neurons by stabilizing the structural and functional integrity of the biological membranes through the regulation of ionic concentration gradient by its antioxidant properties [26]. Similarly, the results on the cholinergic system indicated that chronic administration of D-Galactose caused a significant reduction in ACh level in brain due to dysfunction of cholinergic neurons and reduced activity of Choline acetyltransferase [27] while elevation in AChE activity was responsible for cognitive deficit, this condition was significantly ameliorated in both the regions of brain such as hippocampus and cerebral cortex by oral supplementation of L. plantarum MTCC1325. This may be associated with its potential antioxidant nature, Acetylcholine producing activities of L. plantarum MTCC1325 and also bidirectional communication between the Gut-Bain Axis (Enteric Nervous System) [28]. The recent reviews on Gut-Bain Axis communication describe the bacteria (micro biome) present in the gastro-intestinal tract may communicate with the brain and nervous system by different ways. Microbes have the ability to produce neurochemicals or neurotransmitters that are exact analoges in structure to those produced by the host nervous system and act as vehicles for neurotransmitters and influence the mood and behavior [29]. Microbes have also shown immunomodulatory effect by the release of host immune factors such as cytokines and inflammatory mediators that have known neuronal targets within both the CNS & ENS [30]. Most of the lactic acid bacteria and Probiotics may also activate the vagal nerves, which interacts with all neurons involved in the alleviation of behavioural changes like anxiety, learning and memory, Depression etc. [28]. It has been demonstrated that a probiotic bacterium (L. rhamnosus JB-1) influences the emotional behaviour in mice mediated via GABA receptor [31]. Hence by above studies, it is observed that probiotics especially LAB could be useful in preventing/treating D-Galactose Induced Alzheimer's Disease. However, further research is required on higher mammalian experimental models such as rabbits, owl monkeys, vervet monkeys, squirrel monkeys, and so on to better understand the possible role of Lactobacillus strains in the protection against neurodegenerative diseases. Conclusion Antioxidant and ACh producing L. plantarum MTCC 1325 has Anti-Alzheimer properties against D-Galactose induced Alzheimer's disease since it resulted in body weight gain and organ index, improved the behavioral activity and learning skills through an elevation in the cholinergic neurotransmitter in the hippocampus and cerebral cortex regions of the brain and restored histopathological abnormalities back to the normal conditions.All these preliminary findings suggested that, the L. plantarum MTCC 1325 might have exerted ameliorative effect against Alzheimer's disease induced by D-Galactose. References Alzheimer's and Dementia in India. Available from: http://www.alz.org/in/dementia-alzheimers-en.asp. Accessed on 3rd March, 2017. Changing the Trajectory of Alzheimer's Disease. Available from: http://www.alz.org/alzheimers_disease_trajectory.asp. Accessed on 3rd March, 2017. Sperling RA, Aisen PS, Beckett LA, Bennett DA, Craft S, Fagan AM, Iwatsubo T, Jack CR, Kaye J, Montine TJ, Park DC. Toward defining the preclinical stages of Alzheimer's disease: Recommendations from the National Institute on Aging-Alzheimer's Association workgroups on diagnostic guidelines for Alzheimer's disease. Alzheimer's & dementia. 2011 May 31;7(3):280-92. Mattson MP. Pathways towards and away from Alzheimer's disease. Nature. 2004 Aug 5;430(7000):631-9. Bubici C, Papa S, Dean K, Franzoso G. 2006. Mutual crosstalk between reactive oxygen species and nuclear factorkappa B: molecular basis and biological significance. Oncogene 25: 6731-6748. Chapple IL. 1997. Reactive oxygen species and antioxidants in inflammatory diseases. J. Clin. Periodontol. 24: 287-296. Yu BP, Yang R. 1996. Critical evaluation of the free radical theory of aging. Ann. NY Acad. Sci. 786: 1-11. Butterfield DA, Reed T, Newman SF, Sultana R. Roles of amyloid β-peptide-associated oxidative stress and brain protein modifications in the pathogenesis of Alzheimer's disease and mild cognitive impairment. Free Radical Biology and Medicine. 2007 Sep 1;43(5):658-77. Lei M, Su Y, Hua X, Ding J, Han Q, Hu G, et al. Chronic systemic injection of D-galactose impairs the septohippocampal cholinergic system in rats. Neuroreport. 2008; 19: 1611-1615. Ho S, Liu J, Wu R. Establishment of the mimetic aging effect in mice caused by D-galactose. Biogerontology 2003;4:15e8. Lei M, Hua X, Xiao M, Ding J, Han Q, Hu G. Impairments of astrocytes are involved in the d-galactose-induced brain aging. Biochem Biophys Res Commun 2008;369:1082e7. Zhang Z, Fan S, Zheng Y, Lu J, Wu D, Shan Q, et al. Purple sweet potato color attenuates oxidative stress and inflammatory response induced by d-galactose in mouse liver. Food Chem Toxicol 2009;47:496e501. Woo JY, Gu W, Kim KA, Jang SE, Han MJ, Kim DH. Lactobacillus pentosus var. plantarum C29 ameliorates memory impairment and inflammaging in a D-galactose-induced accelerated aging mouse model. Anaerobe. 2014 Jun 30;27:22-6. Gill R, Tsung A, Billiar T. Linking oxidative stress to inflammation: toll-like receptors. Free Radic Biol Med 2010;48:1121e32. Yoo DY, Kim W, Lee CH, Shin BN, Nam SM, Choi JH, et al. Melatonin improves D-galactose-induced aging effects on behavior, neurogenesis, and lipid peroxidation in the mouse dentate gyrus via increasing pCREB expression. J Pineal Res 2012;52:21e8. Bernardeau M, Vernoux JP, Henri-Dubernet S, Guéguen M. Safety assessment of dairy microorganisms: The Lactobacillus genus. Int J Food Microbiol 2008;126(3):278-85. Islam MS, Choi H. Antidiabetic effect of Korean traditional Baechu (Chinese cabbage) kimchi in a type 2 diabetes model of rats. J Med Food 2009;12:292-7. Jung IH, Jung MA, Kim EJ, Hem MJ, Kim DH. Lactobacillus pentosus var. plantarum C29 protects scopolamine induced memory deficit in mice. J Appl Microbiol 2012;113:1498-506. Peng X, Meng J, Chi T, Liu P, Man C, Liu S, et al. Lactobacillus plantarum NDC 75017 alleviates the learning and memory ability in aging rats by reducing mitochindraildysfunction. Exp Ther Med 2014; 8: 1841-6. doi:10.3892/etm.2014.2000. Hanish Singh JC, Alagarsamy V, Diwan PV, Sathesh Kumar S, Nisha JC, Narsimha Reddy Y. Neuroprotective effect of Alpiniagalanga (L.) fractions on Abeta(25-35) induced amnesia in mice. J Ethnopharmacol 2011;138(1):85-91. Girvin GT, Stevenson JW. Cell free" choline acetylase" from Lactobacillus plantarum. Canadian journal of biochemistry and physiology. 1954 Mar 1;32(2):131-46. Cui X, Zuo P, Zhang Q, Li X, Hu Y, Long J, Packer L, Liu J. Chronic systemic D‐galactose exposure induces memory loss, neurodegeneration, and oxidative damage in mice: Protective effects of R‐α‐lipoic acid. Journal of neuroscience research. 2006 Jun 1;83(8):1584-90. Stephenson M, Rowatt E, Harrison K. The production of acetylcholine by a strain of Lactobacillus plantarum. Microbiology. 1947 Sep 1;1(3):279-98. Lane RM, Potkin SG, Enz A. Targeting acetylcholinesterase and butyrylcholinesterase in dementia. International Journal of Neuropsychopharmacology. 2006 Feb 1;9(1):101-24. Yi ZJ, Fu YR, Li M, Gao KS, Zhang XG. Effect of LTA isolated from bifidobacteria on d-galactose-induced aging. Experimental gerontology. 2009 Dec 31;44(12):760-5. Mallikarjuna N, Praveen K, Yellamma K. Role of Lactobacillus plantarum MTCC1325 in membrane-bound transport ATPases system in Alzheimer's disease-induced rat brain. Bioimpacts. 2016;6(4):203-209. Zhang WW, Sun QX, Liu YH, Gao W, Li YH, Lu K, Wang Z. Chronic administration of Liu Wei Dihuang protects rat's brain against D-galactose-induced impairment of cholinergic system. Sheng li xue bao:[Acta physiologica Sinica]. 2011 Jun;63(3):245-55. Liu X, Cao S, Zhang X. Modulation of gut microbiota–brain axis by probioticsprebiotics, and diet. Journal of agricultural and food chemistry. 2015 Sep 1;63(36):7885-95. Lyte M. Microbial endocrinology and nutrition: a perspective on new mechanisms by which diet can influence gut-to-brain communication. PharmaNutrition. 2013 Jan 31;1(1):35-9. Wood JD. Entericneuroimmunophysiology and pathophysiology. Gastroenterol. 2004;127:635-657. Bravo JA, Forsythe P, Chew MV, Escaravage E, Savignac HM, Dinan TG, Bienenstock J, Cryan JF. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proceedings of the National Academy of Sciences. 2011 Sep 20;108(38):16050-5.

Purpose: The present study aims to evaluate a set of oxidative stress biomarkers in the amniotic fluid (AF) of women carrying Down syndrome (DS) fetuses that could prove in vivo the early occurrence of oxidative damage in DS. Experimental design: To assess the extent of protein oxidation in DS AF, we measured protein carbonylation and protein-bound HNE by slot-blot analysis, total and oxidized GSH levels by enzymatic assay and heat shock proteins (HSPs) thioredoxin (Trx) induction by Western blot. Further, by a redox proteomics approach specific targets of protein carbonylation were identified. Results: We found increased levels of oxidative stress, as indexed by increased protein oxidation, lipid peroxidation, reduction of GSH and Trx levels and induction of the HSP response. By a redox proteomics approach, we identified selective proteins which showed increased oxidation in DS fetuses compared with healthy controls. The identified proteins are involved in iron homeostasis (ceruloplasmin and transferin), lipid metabolism (zinc-α2-glycoprotein, retinol-binding protein 4 and apolipoprotein A1) and inflammation (complement C9, α-1B-glycoprotein, collagen α-1V chain) with critical relevance in the clinical outcome of DS. Conclusions and clinical relevance: Our results indicate that oxidative damage is an early event in the DS pathogenesis and might contribute to the development of deleterious DS phenotypes, including abnormal development and AD-like neuropathology.

Doxorubicin (DOX) is an anticancer drug used for the treatment of solid tumors. The ability of DOX to treat cancer is not specific to cancer cells; some of the cells that are normal may also become targets of DOX, thereby altering the normal cellular functions and eventual cell loss. DOX effects have been studied in detail in heart because of its ability to cause cardiomyopathy. The exact mechanism of DOX-induced cardiomyopathy is not completely understood. One of organs that can be affected by DOX is thymus. DOX treatment leads to degeneration of thymus; however, since thymus undergoes age-dependent degeneration, researchers have understudied the effect of DOX on thymus. In the present investigation, we studied the effects of DOX on thymus, an organ that is important for the T-cell maturation. DOX treatment led to loss of cortical cells, decrease lymphopoiesis and increased the number of Hassells corpuscles, a marker of thymus aging. Proteomics analysis led to identification of a number of thymic proteins whose expression are altered by in vivo DOX treatment. Taken together, these results are consistent with the notion that DOX-treatment leads to thymic senescence.

UV solar radiation is the major environmental risk factor for malignant melanoma. A great effort is currently posed on the search of new compounds able to prevent or reduce UV-mediated cell damage. Ferulic acid is a natural compound recently included in the formulation of solar protecting dermatological products. The purpose of the present work was to assess whether its ethyl ester derivative, FAEE, could protect skin melanocytes from UV-induced oxidative stress and cell damage. Experiments on human melanocytes irradiated with UVB showed that FAEE treatment reduced the generation of ROS, with a net decrease of protein oxidation. FAEE treatment was accompanied by an induction of HSP70 and heme oxygenase, by a marked suppression of PARP activation and a significant suppression of apoptosis. Moreover FAEE prevented iNOS induction, thus suppressing the secondary generation of NO-derived oxidizing agents. FAEE may represent a potentially effective pharmacological approach to reduce UV radiation-induced skin damage.

There is significant evidence to show that aging is characterized by a stochastic accumulation of molecular damage and by a progressive failure of maintenance and repair processes. Protective mechanisms exist in the brain which are controlled by vitagenes and include members of the heat shock system, heme oxygenase-I, and Hsp70 as critical determinants of brain stress tolerance. Given the broad cytoprotective properties of the heat shock response, molecules inducing this defense mechanism appear to be possible candidates for novel cytoprotective strategies. Acetyl-L-carnitine is proposed as a therapeutic agent for several neurodegenerative disorders, and the present study reports that treatment for 4 months of senescent rats with acetyl-L-carnitine induces heme oxygenase-1 as well as Hsp70 and SOD-2. This effect was associated with upregulation of GSH levels, prevention of age-related changes in mitochondrial respiratory chain complex expression, and decrease in protein carbonyls and HNE formation. We hypothesize that maintenance or recovery of the activity of vitagenes may delay the aging process and decrease the risk of age-related diseases. Particularly, modulation of endogenous cellular defense mechanisms via acetyl-L-carnitine may represent an innovative approach to therapeutic intervention in diseases causing tissue damage, such as neurodegeneration.

In the CNS, the heme oxygenase (HO) system has been reported to be active and to operate as a fundamental defensive mechanism for neurons exposed to an oxidant challenge. We have recently shown that both curcumin and caffeic acid phenethyl ester, two phenolic natural compounds, potently induce HO-1 expression and activity in rat astrocytes. We have extended our previous findings examining the effects of two other plant-derived phenolic compounds, with analogous chemical structures, in rat astrocytes and neurons. Ethyl ferulate (ethyl 4-hydroxy-3-methoxycinnamate) (EFE), the naturally occurring ester of ferulic acid, was able to induce HO-1 protein expression. Maximal expression of HO-1 mRNA and protein and a significant increase in HO activity were detected after 6 h of incubation with 15 microM EFE in astrocytes and 5 microM EFE in neurons. Higher concentrations of EFE (50 microM) caused a substantial cytotoxic effect with no change in HO-1 protein expression and activity. Exposure of astrocytes to resveratrol, a phytoalexin derived from grapes, resulted in an increase of HO-1 mRNA, but it was not able to induce HO-1 protein expression and activity. Interestingly, preincubation (12 h) of neurons with EFE resulted in an enhanced cellular resistance to glucose oxidase-mediated oxidative damage; this cytoprotective effect was considerably attenuated by zinc protoporphyrin IX, an inhibitor of HO activity. This study identifies a novel natural compound that could be used for therapeutic purposes as a potent inducer of HO-1 for the protection of brain cells against oxidative and neurodegenerative conditions.

It is generally recognized that lipid peroxides play an important role in the pathogenesis of several diseases and that sulfhydryl groups are critically involved in cellular defense against endogenous or exogenous oxidants. Recent evidence indicates that lipid peroxides directly participate in induction of cytoprotective proteins, such as heat shock proteins (Hsps), which play a central role in the cellular mechanisms of stress tolerance. Oxidative damage plays a crucial role in the brain aging process and induction of Hsps is critically utilized by brain cells in the repair process following various pathogenic insults. In the present study, we investigated, in rats 6, 12, and 28 months old, the role of heat shock expression on aging-induced changes in mitochondrial and antioxidant redox status. In the brain expression of Hsp72 and Hsc70 increased with age up to 28 months; at this age the maximum induction was observed in the hippocampus and substantia nigra followed by cerebellum, cortex, septum and striatum. Hsps induction was associated with significant changes in glutathione (GSH) redox state and HNE levels. Interestingly, a significant positive correlation between decrease in GSH and increase in Hsp72 was observed in all brain regions examined during aging. Analysis of mitochondrial complexes showed a progressive decrease of Complex I activity and mRNA expression in the hippocampus and a significant decrease of Complex I and IV activities in the substantia nigra and septum. Our results sustain a role for GSH redox state in Hsp expression. Increase of Hsp expression promotes the functional recovery of oxidatively damaged proteins and protects cells from progressive age-related cell damage. Conceivably, heat shock signal pathway by increasing cellular stress resistance may represent a crucial mechanism of defence against free radical-induced damage occurring in aging brain and in neurodegenerative disorders.

Efficient functioning of maintenance and repair processes seem to be crucial for both survival and physical quality of life. This is accomplished by a complex network of the so-called longevity assurance processes, under control of several genes termed vitagenes. These include members of the heat shock protein system, and there is now evidence that the heat shock response contributes to establishing a cytoprotective state in a wide variety of human conditions, including inflammation, neurodegenerative disorders, and aging. Among the various heat shock proteins, heme oxygenase-1 has received considerable attention; it has been recently demonstrated that heme oxygenase-1 induction, by generating the vasoactive molecule carbon monoxide and the potent antioxidant bilirubin, could represent a protective system potentially active against brain oxidative injury. Acetyl-L-carnitine is proposed as a therapeutic agent for several neurodegenerative disorders. Accordingly, we report here that treatment of astrocytes with acetyl-L-carnitine induces heme oxygenase-1 in a dose- and time-dependent manner and that this effect was associated with up-regulation of heat shock protein 60 as well as high expression of the redox-sensitive transcription factor Nrf2 in the nuclear fraction of treated cells. In addition, we show that addition of acetyl-L-carnitine to astrocytes, prior to proinflammatory lipopolysaccharide- and interferon-gamma-induced nitrosative stress, prevents changes in mitochondrial respiratory chain complex activity, protein nitrosation and antioxidant status induced by inflammatory cytokine insult. Given the broad cytoprotective properties of the heat shock response, molecules inducing this defense mechanism appear to be possible candidates for novel cytoprotective strategies. Particularly, manipulation of endogenous cellular defense mechanisms via acetyl-L-carnitine may represent an innovative approach to therapeutic intervention in diseases causing tissue damage, such as neurodegeneration. We hypothesize that maintenance or recovery of the activity of vitagenes may delay the aging process and decrease the risk of age-related diseases. Copyright (c) 2005 Wiley-Liss, Inc.