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Reactive Oxygen Species Production (reactive + oxygen_species_production)
Selected AbstractsEvidence of oxidative stress in bluegill sunfish (Lepomis macrochirus) liver microsomes simultaneously exposed to solar ultraviolet radiation and anthraceneENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 7 2000Jonghoon Choi Abstract Many polycyclic aromatic hydrocarbons (PAHs) are acutely toxic to fish and other aquatic organisms in the presence of environmentally realistic intensities of solar ultraviolet radiation (SUVR). However, the biochemical mechanism of this toxicity is not well established. In this study, increased levels of both reactive oxygen species production and lipid peroxidation were hypothesized as a toxic mechanism. To test this hypothesis, the production of superoxide anion and of a lipid peroxidation product (malondialdehyde) was measured in bluegill sunfish (Lepomis machrochirus) liver microsomes. These microsomes were exposed to a representative phototoxic PAH (anthracene [ANT]) and to SUVR and normal laboratory fluorescent light (FLU) in four different combinations: FLU + no ANT, FLU + ANT, SUVR + no ANT, and SUVR + ANT. The highest mean levels of both superoxide anion and malondialdehyde production were observed in the SUVR + ANT group, and these levels were significantly different (p < 0.05) from those in all other treatment groups. We conclude that the photoinduced toxicity of ANT, and possibly of other phototoxic PAHs, manifests at least in part through lipid peroxidation after increased production of reactive oxygen species. [source] A stress survival response in retinal cells mediated through inhibition of the serine,/,threonine phosphatase PP2AEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2010Sorcha Finnegan Abstract Cell survival signalling involving the PI3K/Akt survival pathway can be negatively regulated by several phosphatases including PP2A. When retinal-derived 661W cells were subjected to trophic factor deprivation this initiated a survival response through inhibition of the activity of PP2A and subsequent upregulation of the Erk and Akt survival pathways. We show this survival response via inhibition of PP2A activity was due in part to increased reactive oxygen species production when retinal cells were deprived of trophic factors. Inhibition of PP2A activity was mediated by a rapid and transient increase in phosphorylation at Tyr307, accompanied by an increase in demethylation and a decrease in the methylated form. Pre-treatment with N -acetyl- l -cysteine, which is involved in scavenging reactive oxygen species, prevented PP2A inhibition and subsequent upregulation of survival pathways. Pre-treatment with the Src family kinase inhibitor PP2 resulted in approximately 50% reduction in cellular levels of phospho-PP2A in trophic factor-deprived 661W cells, suggesting an Src tyrosine kinase had a role to play in this redox regulation of cell survival. We observed similar events in the rd10 mouse retina where there was an increased survival response prior to retinal cell death mediated through an increase in both phospho-PP2A and phospho-Gsk. Together, these results demonstrate that when retinal cells are stressed there is an initial struggle to survive, mediated through inhibition of PP2A and subsequent upregulation of survival pathways, and that these events occur simultaneously with production of reactive oxygen species, thus suggesting an important cell-signalling role for reactive oxygen species. [source] Inhibition of glutamine transport into mitochondria protects astrocytes from ammonia toxicityGLIA, Issue 8 2007V. B. R. Pichili Abstract Hepatic encephalopathy (HE) is a major neurological complication that occurs in the setting of severe liver failure. Ammonia is a key neurotoxin implicated in this condition, and astrocytes are the principal neural cells histopathologically and functionally affected. Although the mechanism by which ammonia causes astrocyte dysfunction is incompletely understood, glutamine, a by-product of ammonia metabolism, has been strongly implicated in many of the deleterious effects of ammonia on astrocytes. Inhibiting mitochondrial glutamine hydrolysis in astrocytes mitigates many of the toxic effects of ammonia, suggesting the involvement of mitochondrial glutamine metabolism in the mechanism of ammonia neurotoxicity. To determine whether mitochondriaare indeed the organelle where glutamine exerts its toxic effects, we examined the effect of L -histidine, an inhibitor of mitochondrial glutamine transport, on ammonia-mediated astrocyte defects. Treatment of cultured astrocytes with L -histidine completely blocked or significantly attenuated ammonia-induced reactive oxygen species production, cell swelling, mitochondrial permeability transition, and loss of ATP. These findings implicate mitochondrial glutamine transport in the mechanism of ammonia neurotoxicity. © 2007 Wiley-Liss, Inc. [source] CCR2 promotes hepatic fibrosis in mice,HEPATOLOGY, Issue 1 2009Ekihiro Seki Chemokines and chemokine receptors contribute to the migration of hepatic stellate cells (HSCs) and Kupffer cells, two key cell types in fibrogenesis. Here, we investigate the role of CCR2, the receptor for monocyte chemoattractant protein (MCP)-1, MCP-2, and MCP-3, in hepatic fibrosis. Hepatic CCR2, MCP-1, MCP-2, and MCP-3 messenger RNA expression was increased after bile duct ligation (BDL). Both Kupffer cells and HSCs, but not hepatocytes, expressed CCR2. BDL- and CCl4 -induced fibrosis was markedly reduced in CCR2,/, mice as assessed through collagen deposition, ,-smooth muscle actin expression, and hepatic hydroxyproline content. We generated CCR2 chimeric mice by the combination of clodronate, irradiation, and bone marrow (BM) transplantation allowing full reconstitution of Kupffer cells, but not HSCs, with BM cells. Chimeric mice containing wild-type BM displayed increased macrophage recruitment, whereas chimeric mice containing CCR2,/, BM showed less macrophage recruitment at 5 days after BDL. Although CCR2 expressed in the BM enhanced macrophage recruitment in early phases of injury, CCR2 expression on resident liver cells including HSCs, but not on the BM, was required for fibrogenic responses in chronic fibrosis models. In vitro experiments demonstrated that HSCs deficient in CCR2,/, or its downstream mediator p47phox,/, did not display extracellular signal-regulated kinase and AKT phosphorylation, chemotaxis, or reactive oxygen species production in response to MCP-1, MCP-2, and MCP-3. Conclusion: Our results indicate that CCR2 promotes HSC chemotaxis and the development of hepatic fibrosis. (HEPATOLOGY 2009.) [source] Erratum: Ursodeoxycholic acid switches oxaliplatin-induced necrosis to apoptosis by inhibiting reactive oxygen species production and activating p53-caspase 8 pathway in HepG2 hepatocellular carcinomaINTERNATIONAL JOURNAL OF CANCER, Issue 2 2010Sung-Chul Lim No abstract is available for this article. [source] Cyclo(His-Pro) promotes cytoprotection by activating Nrf2-mediated up-regulation of antioxidant defenceJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 6 2009Alba Minelli Abstract Hystidyl-proline [cyclo(His-Pro)] is an endogenous cyclic dipeptide produced by the cleavage of thyrotropin releasing hormone. Previous studies have shown that cyclo(His-Pro) protects against oxidative stress, although the underlying mechanism has remained elusive. Here, we addressed this issue and found that cyclo(His-Pro) triggered nuclear accumulation of NF-E2-related factor-2 (Nrf2), a transcription factor that up-regulates antioxidant-/electrophile-responsive element (ARE-EpRE)-related genes, in PC12 cells. Cyclo(His-Pro) attenuated reactive oxygen species production, and prevented glutathione depletion caused by glutamate, rotenone, paraquat and ,-amyloid treatment. Moreover, real-time PCR analyses revealed that cyclo(His-Pro) induced the expression of a number of ARE-related genes and protected cells against hydrogen peroxide-mediated apoptotic death. Furthermore, these effects were abolished by RNA interference-mediated Nrf2 knockdown. Finally, pharmacological inhibition of p-38 MAPK partially prevented both cyclo(His-Pro)-mediated Nrf2 activation and cellular protection. These results suggest that the signalling mechanism responsible for the cytoprotective actions of cyclo(His-Pro) would involve p-38 MAPK activation leading to Nrf2-mediated up-regulation of antioxidant cellular defence. [source] Nicotinamide enhances mitochondria quality through autophagy activation in human cellsAGING CELL, Issue 4 2009Hyun Tae Kang Summary Nicotinamide (NAM) treatment causes a decrease in mitochondrial respiration and reactive oxygen species production in primary human fibroblasts and extends their replicative lifespan. In the current study, it is reported that NAM treatment induces a decrease in mitochondrial mass and an increase in membrane potential (,,m) by accelerating autophagic degradation of mitochondria. In the NAM-treated cells, the level of LC3-II as well as the number of LC3 puncta and lysosomes co-localizing with mitochondria substantially increased. Furthermore, in the NAM-treated cells, the levels of Fis1, Drp1, and Mfn1, proteins that regulate mitochondrial fission and fusion, increased and mitochondria experienced dramatic changes in structure from filaments to dots or rings. This structural change is required for the decrease of mitochondrial mass indicating that NAM accelerates mitochondrial autophagy, at least in part, by inducing mitochondrial fragmentation. The decrease in mitochondria mass was attenuated by treatment with cyclosporine A, which prevents the loss of mitochondrial membrane potential by blocking the mitochondrial permeability transition, suggesting autophagic degradation selective for mitochondria with low ,,m. All these changes were accompanied by and dependent on an increase in the levels of GAPDH, and are blocked by inhibition of the cellular conversion of NAM to NAD+. Taken together with our previous findings, these results suggest that up-regulation of GAPDH activity may prolong healthy lifespan of human cells through autophagy-mediated mitochondria quality maintenance. [source] Virus-like particles associated with brown muscle disease in Manila clam, Ruditapes philippinarum, in Arcachon Bay (France)JOURNAL OF FISH DISEASES, Issue 7 2009C Dang Abstract Recently, Manila clam, Ruditapes philippinarum, populations have suffered mortalities in Arcachon Bay (SW France). Mortality was associated with extensive lesions of the posterior adductor muscle, which become progressively brown and calcified. Ultrastructural observations by transmission electron microscopy revealed tissue degradation with necrotized muscle fibres and granulocytomas. Unenveloped virus-like particles (VLPs) were detected in muscle, granulocytic, epithelial and rectal cells. VLPs were abundant in the extracellular space, in the cytoplasm (free or enclosed in vesicles) and in the nucleoplasm of granulocytes. Nuclei and mitochondria of granulocytes displayed changes which suggested reactive oxygen species production and apoptosis induction. VLPs exhibited an icosahedral structure with a diameter of 25 to 35 nm. These observations suggest that the VLPs could belong to the family Picornaviridae or the Parvoviridae. [source] Necrostatin-1 protects against glutamate-induced glutathione depletion and caspase-independent cell death in HT-22 cellsJOURNAL OF NEUROCHEMISTRY, Issue 5 2007Xingshun Xu Abstract Glutamate, a major excitatory neurotransmitter in the CNS, plays a critical role in neurological disorders such as stroke and Parkinson's disease. Recent studies have suggested that glutamate excess can result in a form of cell death called glutamate-induced oxytosis. In this study, we explore the protective effects of necrostatin-1 (Nec-1), an inhibitor of necroptosis, on glutamate-induced oxytosis. We show that Nec-1 inhibits glutamate-induced oxytosis in HT-22 cells through a mechanism that involves an increase in cellular glutathione (GSH) levels as well as a reduction in reactive oxygen species production. However, Nec-1 had no protective effect on free radical-induced cell death caused by hydrogen peroxide or menadione, which suggests that Nec-1 has no antioxidant effects. Interestingly, the protective effect of Nec-1 was still observed when cellular GSH was depleted by buthionine sulfoximine, a specific and irreversible inhibitor of glutamylcysteine synthetase. Our study further demonstrates that Nec-1 significantly blocks the nuclear translocation of apoptosis-inducing factor (a marker of caspase-independent programmed cell death) and inhibits the integration of Bcl-2/adenovirus E1B 19 kDa-interacting protein 3 (a pro-death member of the Bcl-2 family) into the mitochondrial membrane. Taken together, these results demonstrate for the first time that Nec-1 prevents glutamate-induced oxytosis in HT-22 cells through GSH related as well as apoptosis-inducing factor and Bcl-2/adenovirus E1B 19 kDa-interacting protein 3-related pathways. [source] Differential effects of the mitochondrial uncoupling agent, 2,4-dinitrophenol, or the nitroxide antioxidant, Tempol, on synaptic or nonsynaptic mitochondria after spinal cord injuryJOURNAL OF NEUROSCIENCE RESEARCH, Issue 1 2009Samir P. Patel Abstract We recently documented the progressive nature of mitochondrial dysfunction over 24 hr after contusion spinal cord injury (SCI), but the underlying mechanism has not been elucidated. We investigated the effects of targeting two distinct possible mechanisms of mitochondrial dysfunction by using the mitochondrial uncoupler 2,4-dinitrophenol (2,4-DNP) or the nitroxide antioxidant Tempol after contusion SCI in rats. A novel aspect of this study was that all assessments were made in both synaptosomal (neuronal)- and nonsynaptosomal (glial and neuronal soma)-derived mitochondria 24 hr after injury. Mitochondrial uncouplers target Ca2+ cycling and subsequent reactive oxygen species production in mitochondria after injury. When 2,4-DNP was injected 15 and 30 min after injury, mitochondrial function was preserved in both populations compared with vehicle-treated rats, whereas 1 hr postinjury treatment was ineffective. Conversely, targeting peroxynitrite with Tempol failed to maintain normal bioenergetics in synaptic mitochondria, but was effective in nonsynaptic mitochondria when administered 15 min after injury. When administered at 15 and 30 min after injury, increased hydroxynonenal, 3-NT, and protein carbonyl levels were significantly reduced by 2,4-DNP, whereas Tempol only reduced 3-NT and protein carbonyls after SCI. Despite such antioxidant effects, only 2,4-DNP was effective in preventing mitochondrial dysfunction, indicating that mitochondrial Ca2+ overload may be the key mechanism involved in acute mitochondrial damage after SCI. Collectively, our observations demonstrate the significant role that mitochondrial dysfunction plays in SCI neuropathology. Moreover, they indicate that combinatorial therapeutic approaches targeting different populations of mitochondria holds great potential in fostering neuroprotection after acute SCI. © 2008 Wiley-Liss, Inc. [source] P2Y receptor-activating nucleotides modulate cellular reactive oxygen species production in dissociated hippocampal astrocytes and neurons in culture independent of parallel cytosolic Ca2+ rise and change in mitochondrial potentialJOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2007Stefan Kahlert Abstract With mixed cultures of hippocampal astrocytes and neurons, we investigated the influence of nucleotides on cytosolic Ca2+ level, generation of reactive oxygen species (ROS), and mitochondrial potential. We employed ATP and four purine/pyrimidine derivates, which are P2Y receptor subtype-preferring agonists. Stimulation with ATP, a P2Y1/2/4 receptor agonist in rat, caused a large cytosolic Ca2+ increase in astrocytes and a considerably smaller Ca2+ response in neighboring neurons. The P2Y1 receptor antagonist MRS2179 completely blocked the ATP-induced Ca2+ response in astrocytes and neurons. Application of ATP significantly reduced the mitochondrial potential in neurons, which was not inhibited by MRS2179. Interestingly, MRS2179 mediated a mitochondrial depolarization without affecting the cytosolic Ca2+ level. Stimulation with UDP, a P2Y6 receptor agonist; UTP, a P2Y2/4 receptor agonist; 2MeSATP, a P2Y1 receptor agonist; or 2MeSADP, a P2Y1/12/13 receptor agonist, evoked significant Ca2+ responses in astrocytes but small Ca2+ responses in neurons. In astrocytes, there was an inverse relationship between the amplitude of the cytosolic Ca2+ peak and the rate of ROS generation in response to nucleotide application. Activation with UDP resulted in the highest ROS generation that we detected, whereas 2MeSADP and 2MeSATP reduced the ROS generation below the basal level. 2MeSADP and UDP caused mitochondrial depolarization of comparable size. Thus, neither in astrocytes nor in neurons did the degree of mitochondrial depolarization correlate with ROS generation. Nucleotides acting via P2Y receptors can modulate ROS generation of hippocampal neurons without acutely changing the cytosolic Ca2+ level. Thus, ROS might function as a signaling molecule upon nucleotide-induced P2Y receptor activation in brain. © 2007 Wiley-Liss, Inc. [source] Oral malodorous compound causes apoptosis and genomic DNA damage in human gingival fibroblastsJOURNAL OF PERIODONTAL RESEARCH, Issue 4 2008K. Yaegaki Background and Objective:, Volatile sulfur compounds are the main cause of halitosis. Hydrogen sulfide is one of these volatile sulfur compounds and the principal malodorous compound in physiological halitosis. Periodontally pathogenic activities of hydrogen sulfide have been previously reported. Hydrogen sulfide induces apoptotic cell death in aorta smooth muscle cells and in other tissues. Apoptosis plays an important role in the onset and progress of periodontitis. The objective of this study was to determine whether hydrogen sulfide causes apoptosis in human gingival fibroblasts. Material and methods:, Necrotic cells were detected using a lactate dehydrogenase assay. Apoptosis was ascertained using a histone-complexed DNA fragment assay and flow cytometry. The level of caspase 3, a key enzyme in apoptotic signaling, was also measured, and the effects of hydrogen sulfide on reactive oxygen species and superoxide dismutase were assessed. DNA damage caused by hydrogen sulfide was examined by means of single-cell gel electrophoresis. Results:, After 72 h of incubation with 100 ng/mL of hydrogen sulfide, necrosis was found in less than 10% of human gingival fibroblasts, whereas apoptosis was significantly increased (p < 0.05). Superoxide dismutase activity was strongly inhibited, and reactive oxygen species production was enhanced, after 48 and 72 h of incubation. Caspase 3 activity was also increased after 72 h of incubation (p < 0.01). Tail length, percentage of DNA in tail, and tail moment, measured by single-cell gel electrophoresis, were also intensified after 72 h of incubation (p < 0.001). Conclusion:, Hydrogen sulfide caused apoptosis and DNA damage in human gingival fibroblasts. An increased level of reactive oxygen species stimulated by hydrogen sulfide may induce apoptosis and DNA strand breaks. [source] Impact of amino acid substitutions in the hepatitis C virus genotype 1b core region on liver steatosis and hepatic oxidative stress in patients with chronic hepatitis CLIVER INTERNATIONAL, Issue 4 2010Yoshihiko Tachi Abstract Background: Liver steatosis and hepatic oxidative stress are the histopathological features of chronic hepatitis C. Hepatitis C virus (HCV) genotype 1 core protein induces hepatic steatosis and reactive oxygen species production in transgenic mice. The amino acid substitutions in the HCV core region appear to be related to hepatocarcinogenesis. Aims: The aim of this study was to clarify the impact of mutations in the HCV core region on oxidative stress and lipid metabolism in patients with chronic hepatitis C. Methods: Sixty-seven patients (35 men, 32 women; mean age, 58.4 ± 10.2 years) with chronic hepatitis C with high titres (>5 log IU/ml) were enrolled. Substitutions in amino acids 70, 75 and 91 of the HCV genotype 1b core region, the percentage of hepatic steatosis, and hepatic 8-hydroxy-2,-deoxyguanosine (8-OHdG) levels were investigated in all patients. Urinary 8-OHdG levels were measured in 35 patients. Results: Body mass index, alanine aminotransferase, ,-glutamyl transferase, and triglyceride levels and substitutions of amino acid 70/Q (glutamine) were significantly associated with the presence of steatosis on univariate analysis. Multivariate analysis showed that substitution of amino acid 70 of glutamine and triglyceride levels were the independent factors related to liver steatosis. Hepatic and urinary 8-OHdG levels were significantly higher in patients with methionine at amino acid 91 of the HCV core region than in those with leucine. Conclusion: Substitutions in the amino acids of the HCV genotype1b core region are associated with hepatic steatosis and oxidative stress in patients with chronic hepatitis C. [source] Chrysophanol induces necrosis through the production of ROS and alteration of ATP levels in J5 human liver cancer cellsMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 7 2010Chi-Cheng Lu Abstract Anthraquinone compounds have been shown to induce apoptosis in different cancer cell types. Effects of chrysophanol, an anthraquinone compound, on cancer cell death have not been well studied. The goal of this study was to examine if chrysophanol had cytotoxic effects and if such effects involved apoptosis or necrosis in J5 human liver cancer cells. Chrysophanol induced necrosis in J5 cells in a dose- and time-dependent manner. Non-apoptotic cell death was induced by chrysophanol in J5 cells and was characterized by caspase independence, delayed externalization of phosphatidylserine and plasma membrane disruption. Blockage of apoptotic induction by a general caspase inhibitor (z-VAD-fmk) failed to protect cells against chrysophanol-induced cell death. The levels of reactive oxygen species production and loss of mitochondrial membrane potential (,,m) were also determined to assess the effects of chrysophanol. However, reductions in adenosine triphosphate levels and increases in lactate dehydrogenase activity indicated that chrysophanol stimulated necrotic cell death. In summary, human liver cancer cells treated with chrysophanol exhibited a cellular pattern associated with necrosis and not apoptosis. [source] Menadione sodium bisulphite: a novel plant defence activator which enhances local and systemic resistance to infection by Leptosphaeria maculans in oilseed rapePLANT PATHOLOGY, Issue 4 2003A. A. Borges Pretreatment of the first true leaves of oilseed rape plants (Brassica napus cv. Bristol) with menadione sodium bisulphite (MSB) locally and systemically induced resistance, as shown by reduced lesion size and number, to infection by the fungal pathogen Leptosphaeria maculans, the causal agent of stem canker. Using a known systemic activator of salicylic acid-dependent PR-1 induction, acibenzolar- S -methyl (BTH; S -methylbenzo[1,2,3]thiadiazole-7-carbothiate) as a comparison, real-time PCR expression analysis of genes encoding a pathogenesis-related protein 1 (PR-1) and an ascorbate peroxidase (APX) demonstrated a systemic enhancement of APX expression in MSB-pretreated plants, with no effect on PR-1 expression, suggesting augmented reactive oxygen species production in MSB-pretreated plants. The results demonstrate MSB to be an effective resistance activator in oilseed rape, and potentially useful for the control of stem canker. [source] Chloride intracellular channel 1 identified using proteomic analysis plays an important role in the radiosensitivity of HEp-2 cells via reactive oxygen species productionPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 14 2010Jae-Sung Kim Abstract The nature of the molecules underlying the radioresistance phenotype of laryngeal cancer cells remains to be established. We initially generated radioresistant laryngeal cancer cell lines from human HEp-2 cells with fractionated radiation. These RR-HEp-2 cells and isolated clones displayed more radioresistant and anti-apoptotic phenotypes than parental HEp-2 cells after radiation. Characteristics of RR-Hep-2 cell lines were confirmed by upregulation of radioresistance-related genes, such as epidermal growth factor receptor, Hsp90, and Bcl-xl. Subsequently, we examined proteome changes between HEp-2 and RR-HEp-2 cells and identified 16 proteins showing significantly altered expression levels. Interestingly, protein expression of chloride intracellular channel 1 (CLIC1) was markedly suppressed in RR-HEp-2 cells, compared with non-irradiated control cells. Suppression of CLIC1 with an indanyloxyacetic acid-94 or small interfering RNA led to radioresistance in HEp-2 cells by suppressing the radiation-induced cellular ROS level. However, ectopic overexpression of CLIC1 induced radiosensitivity in RR-HEp-2 cells via induction of ROS level after radiation, suggesting that the protein acts as a positive regulator of ROS production. Our results collectively indicate that suppression of CLIC1 contributes to acquisition of the radioresistance phenotype of laryngeal cancer cells via inhibition of ROS production, implying that this protein is an important candidate molecule for radiotherapy in radioresistant laryngeal cancer cells. [source] Apigenin drives the production of reactive oxygen species and initiates a mitochondrial mediated cell death pathway in prostate epithelial cellsTHE PROSTATE, Issue 2 2005Colm Morrissey Abstract BACKGROUND Phytoestrogens may reduce tumorigenesis in prostate cancer. We screened five phytoestrogens for their effect on cell growth and apoptosis in PWR-1E, LNCaP, PC-3, and DU145 prostate epithelial cells in vitro. METHODS We assessed cell number, proliferation, and apoptosis using crystal violet assays, flow cytometric analysis, and TUNEL. Focusing specifically on apigenin we assessed the ability of calpain, serine protease, caspase, estrogen receptor, and ceramide synthase inhibitors to block apigenin induced apoptosis. We also analyzed caspase 3, 7, 8, 9, Bcl-2, Bax, Bid, and cytochrome C by Western analysis, and mitochondrial permeability and reactive oxygen species production by flow cytometry using mitosensorTM and DCFH-DA, respectively. RESULTS Apigenin and silybinin significantly reduced cell number, with apigenin inducing apoptosis in PWR-1E, LNCaP, PC-3, and DU145 cells. The PC-3 and DU145 cells were less susceptible to apigenin induced apoptosis then LNCaP and PWR-1E cells. The induction of apoptosis by apigenin was caspase dependent. Apigenin generated reactive oxygen species, a loss of mitochondrial Bcl-2 expression, mitochondrial permeability, cytochrome C release, and the cleavage of caspase 3, 7, 8, and 9 and the concomitant cleavage of the inhibitor of apoptosis protein, cIAP-2. The overexpression of Bcl-2 in LNCaP B10 cells reduced the apoptotic effects of apigenin. CONCLUSIONS Apigenin induces cell death in prostate epithelial cells using a mitochondrial mediated cell death pathway. Bcl-2 has a role in inhibiting apigenin induced cell death in prostate epithelial cells. © 2004 Wiley-Liss, Inc. [source] Uncoupling proteins: A complex journey to function discoveryBIOFACTORS, Issue 5 2009Federica Cioffi Abstract Since their discovery, uncoupling proteins have aroused great interest due to the crucial importance of energy-dissipating system for cellular physiology. The uncoupling effect and the physiological role of UCP1 (the first-described uncoupling protein) are well established. However, the reactions catalyzed by UCP1 homologues (UCPs), and their physiological roles are still under debate, with the literature containing contrasting results. Current hypothesis propose several physiological functions for novel UCPs, such as: (i) attenuation of reactive oxygen species production and protection against oxidative damage, (ii) thermogenic function, although UCPs do not generally seem to affect thermogenesis, UCP3 can be thermogenic under certain conditions, (iii) involvement in fatty acid handling and/or transport, although recent experimental evidence argues against the previously hypothesized role for UCPs in the export of fatty acid anions, (iv) fatty acid hydroperoxide export, although this function, due to the paucity of the experimental evidence, remains hypothetical, (v) Ca2+ uptake, although results for and against a role in Ca2+ uptake are still emerging, (vi) a signaling role in pancreatic beta cells, where it attenuates glucose-induced insulin secretion. From the above, it is evident that more research will be needed to establish universally accepted functions for UCPs. © 2009 International Union of Biochemistry and Molecular Biology, Inc. [source] Malonate induces cell death via mitochondrial potential collapse and delayed swelling through an ROS-dependent pathwayBRITISH JOURNAL OF PHARMACOLOGY, Issue 4 2005Francisco J Fernandez-Gomez 1Herein we study the effects of the mitochondrial complex II inhibitor malonate on its primary target, the mitochondrion. 2Malonate induces mitochondrial potential collapse, mitochondrial swelling, cytochrome c (Cyt c) release and depletes glutathione (GSH) and nicotinamide adenine dinucleotide coenzyme (NAD(P)H) stores in brain-isolated mitochondria. 3Although, mitochondrial potential collapse was almost immediate after malonate addition, mitochondrial swelling was not evident before 15 min of drug presence. This latter effect was blocked by cyclosporin A (CSA), Ruthenium Red (RR), magnesium, catalase, GSH and vitamin E. 4Malonate added to SH-SY5Y cell cultures produced a marked loss of cell viability together with the release of Cyt c and depletion of GSH and NAD(P)H concentrations. All these effects were not apparent in SH-SY5Y cells overexpressing Bcl-xL. 5When GSH concentrations were lowered with buthionine sulphoximine, cytoprotection afforded by Bcl-xL overexpression was not evident anymore. 6Taken together, all these data suggest that malonate causes a rapid mitochondrial potential collapse and reactive oxygen species production that overwhelms mitochondrial antioxidant capacity and leads to mitochondrial swelling. Further permeability transition pore opening and the subsequent release of proapoptotic factors such as Cyt c could therefore be, at least in part, responsible for malonate-induced toxicity. British Journal of Pharmacology (2005) 144, 528,537. doi:10.1038/sj.bjp.0706069 [source] | |||||||||||||