slayadragon
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Per Gerwyn's suggestion, I'm in the process of putting together a comprehensive literature review on the effects of trichothecenes (a type of mold toxin made by Stachybotrys and certain other toxic molds) as they might relate to Chronic Fatigue Syndrome.
There is a lot of this research, so the project is going to take a bit more time to finish.
In the meantime, I'm going to post abstracts here.
The ones in this post are related to oxidative stress, which many CFS doctors (e.g. Dr. Cheney) now believe are a core part of this disease.
Best, Lisa
*
Markkanen Penttinen P, Pelkonen J, Tapanainen M, Mki-Paakkanen J, Jalava PI, Hirvonen MR. Co-cultivated damp building related microbes Streptomyces californicus and Stachybotrys chartarum induce immunotoxic and genotoxic responses via oxidative stress. Inhal Toxicol. 2009 Aug;21(10):857-67. PMID: 19459771
Oxidative stress has been proposed to be one mechanism behind the adverse health outcomes associated with living in a damp indoor environment. In the present study, the capability of damp building-related microbes Streptomyces californicus and Stachybotrys chartarum to induce oxidative stress was evaluated in vitro. In addition, the role of oxidative stress in provoking the detected cytotoxic, genotoxic, and inflammatory responses was studied by inhibiting the production of reactive oxygen species (ROS) using N-acetyl-l-cysteine (NAC). RAW264.7 macrophages were exposed in a dose- and time-dependent manner to the spores of co-cultivated S. californicus and S. chartarum, to their separately cultivated spore-mixture, or to the spores of these microbes alone. The intracellular peroxide production and cytotoxicity were measured by flow cytometric analysis, nitric oxide production was analyzed by the Griess method, DNA damage was determined by the comet assay, and cytokine production was measured by an immunochemical ELISA (enzyme-linked immunosorbent assay). All the studied microbial exposures triggered oxidative stress and subsequent cellular damage in RAW264.7 macrophages. The ROS scavenger, NAC, prevented growth arrest, apoptosis, DNA damage, and cytokine production induced by the co-culture since it reduced the intracellular level of ROS within macrophages. In contrast, the DNA damage and cell cycle arrest induced by the spores of S. californicus alone could not be prevented by NAC. Bioaerosol-induced oxidative stress in macrophages may be an important mechanism behind the frequent respiratory symptoms and diseases suffered by residents of moisture damaged buildings. Furthermore, microbial interactions during co-cultivation stimulate the production of highly toxic compound(s) which may significantly increase oxidative damage.
*
Wang H, Yadav JS. DNA damage, redox changes, and associated stress-inducible signaling events underlying the apoptosis and cytotoxicity in murine alveolar macrophage cell line MH-S by methanol-extracted Stachybotrys chartarum toxins. Toxicol Appl Pharmacol. 2006 Aug 1;214(3):297-308. PMID: 16476459
Spore-extracted toxins of the indoor mold Stachybotrys chartarum (SC) caused cytotoxicity (release of lactate dehydrogenase), inhibition of cell proliferation, and cell death in murine alveolar macrophage cell line MH-S in a dose- and time-dependent manner.
The apoptotic dose of SC toxins did not induce detectable nitric oxide and pro-inflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) but showed exacerbated cytotoxicity in presence of a non-apoptotic dose of the known pro-inflammatory agent LPS (10 ng/ml).
Intracellular reduced glutathione (GSH) level showed a significant decrease beginning at 9 h of the toxin treatment whereas oxidized glutathione (GSSG) showed a corresponding significant increase, indicating a delayed onset of oxidative stress in the apoptosis process.
The toxin-treated macrophages accumulated p53, an indicator of DNA damage response, and showed activation of the stress-inducible MAP kinases, JNK, and p38
Chemical blocking of either p38 or p53 inhibited in part the SC toxin-induced apoptosis whereas blocking of JNK did not show any such effect.
*
Wang H, Yadav JS. Global gene expression changes underlying Stachybotrys chartarum toxin-induced apoptosis in murine alveolar macrophages: evidence of multiple signal transduction pathways. Apoptosis. 2007 Mar;12(3):535-48. PMID: 17186382
The overall mechanism(s) underlying macrophage apoptosis caused by the toxins of the indoor mold Stachybotrys chartarum (SC) are not yet understood.
The toxin-regulated genes corresponded to multiple cellular processes, including cell growth, proliferation and death, inflammatory/immune response, genotoxic stress and oxidative stress, and to the underlying multiple signal transduction pathways involving MAPK-, NF-kB-, TNF-, and p53-mediated signaling.
Transcription factor NF-kB showed dynamic temporal changes, characterized by an initial activation and a subsequent inhibition.
Up-regulation of a battery of DNA damage-responsive and DNA repair genes in the early stage of the treatment suggested a possible role of genotoxic stress in the initiation of apoptosis.
Simultaneous expression changes in both pro-survival genes and pro-apoptotic genes indicated the role of a critical balance between the two processes in SC toxin-induced apoptosis.
Taken together, the results imply that multiple signaling pathways underlie the SC toxin-induced apoptosis in alveolar macrophages.
*
Rakkestad KE, Skaar I, Ansteinsson VE, Solhaug A, Holme JA, Pestka JJ, Samuelsen JT, Dahlman HJ, Hongslo JK, Becher R. DNA damage and DNA damage responses in THP-1 monocytes after exposure to spores of either Stachybotrys chartarum or Aspergillus versicolor or to T-2 toxin. Toxicol Sci. 2010 May;115(1):140-55. PMID: 20150440
We have characterized cell death in THP-1 cells after exposure to heat-treated spores from satratoxin G-producing Stachybotrys chartarum isolate IBT 9631, atranone-producing S. chartarum isolate IBT 9634, and sterigmatocystin-producing Aspergillus versicolor isolate IBT 3781, as well as the trichothecenes T-2 and satratoxin G. Spores induced cell death within 3-6 h, with Stachybotrys appearing most potent.
IBT 9631 induced both apoptosis and necrosis, while IBT 9634 and IBT 3781 induced mostly necrosis. T-2 toxin and satratoxin G caused mainly apoptosis.
Comet assay +/- formamidopyrimidine DNA glycosylase showed that only the spore exposures induced early (3h) oxidative DNA damage. Likewise, only the spores increased the formation of reactive oxygen species (ROS), suggesting that spores as particles may induce ROS formation and oxidative DNA damage.
In conclusion, activation of Chk2 and H2AX correlated with spore- and toxin-induced apoptosis. For IBT 9631 and satratoxin G, additional factors may be involved in triggering apoptosis, most notably p38 activation.
*
Chaudhari M, Jayaraj R, Santhosh SR, Rao PV. Oxidative damage and gene expression profile of antioxidant enzymes after T-2 toxin exposure in mice. J Biochem Mol Toxicol. 2009 May;23(3):212-21. PMID: 19526462.
T-2 toxin showed significant alterations in hepatic alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase.
Significant changes in hepatic lipid peroxidation, depletion of glutathione (GSH), and expression of heat shock protein-70 indicated oxidative damage.
We also evaluated the activity of antioxidant enzymes and compared the gene expression profile by quantitative real-time reverse transcriptase-polymerase chain reaction.
Except for glutathione reductase (GR), there was a significant increase in activity of glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase at 1 LD50 dose.
At 2 LD50 dose, SOD showed decrease in activity, whereas GST, GPx, and catalase showed significant increase.
In contrast, gene expression profile showed downregulation in GR, GPx, GST, and catalase at 1 LD50 dose. At 2 LD50 dose except GSH synthetase, all other genes were downregulated.
The results clearly show oxidative stress as one of the mechanisms of T-2 toxin-mediated toxicity.
*
Zhang X, Jiang L, Geng C, Cao J, Zhong L. The role of oxidative stress in deoxynivalenol-induced DNA damage in HepG2 cells. Toxicon. 2009 Sep 15;54(4):513-8. PMID: 19486909.
The aim of this study was to assess the role of oxidative stress in deoxynivalenol-induced DNA damage, using human hepatoma HepG2 cells.
In order to clarify the underlying mechanisms, we evaluated the level of reactive oxygen species (ROS) production with the 2,7-dichlorofluorescein diacetate (DCFH-DA) assay. Significant increase in the level of ROS was observed in HepG2 cells at a higher concentration (60 microM). The involvement of lipid peroxidation in the DNA damage of DON was confirmed by using immunoperoxidase staining for 8-hydroxydeoxyguanosine (8-OHdG) and by measuring levels of thiobarbituric acid-reactive substances (TBARS), the doses being 7.5-60 microM and 3.75-15 microM, respectively. These results indicate that the DNA damage induced by DON in HepG2 cells is probably related to the oxidative stress.
*
Borutova R, Faix S, Placha I, Gresakova L, Cobanova K, Leng L. Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers. Arch Anim Nutr. 2008 Aug;62(4):303-12. PMID: 18763624
Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg kg(-1), while Group 2 received DON and ZEA at 8.2 and 8.3 mg kg(-1), respectively.
Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma gamma-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and alpha-tocopherol in plasma were not affected by dietary mycotoxins.
Blood phagocytic activity was significantly depressed in Group 1 and 2.
These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.
*
Kouadio JH, Mobio TA, Baudrimont I, Moukha S, Dano SD, Creppy EE. Comparative study of cytotoxicity and oxidative stress induced by deoxynivalenol, zearalenone or fumonisin B1 in human intestinal cell line Caco-2. Toxicology. 2005 Sep 15;213(1-2):56-65. PMID: 16019124
Fusarium toxins such as, deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) have been shown to cause diverse toxic effects in animals and also suspected of disease causation in humans. From the literature and mechanistic point of view, DON binds to the ribosomal peptidyl-transferase and inhibits protein synthesis specifically and DNA synthesis consequently. ZEN known to be genotoxic, binds to 17-beta-estradiol receptors, induces lipid peroxidation, cell death and inhibits protein and DNA synthesis. FB1 disrupts sphingolipid metabolism, induces lipid peroxidation altering the cell membrane and causing cell death.
We intended to compare DON, ZEN and FB1 (1-150 microM) cytotoxic effect and the pathways leading to cell death and related to oxidative stress and macromolecules syntheses in a human intestinal cell line in order to tentatively classify them according to their respective potential toxicity.
The comparison reveals that all three mycotoxins bear, at variable degree, the capability of inducing lipid peroxidation (MDA production) and could be classified above 10 microM in decreasing potency order FB1>DON>ZEN.
This effect seems to be related to their common target that is the mitochondria as revealed by MTT test and seemingly not related to sphingoids accumulation concerning FB1.
DON and ZEN also adversely affect lysosomes in contrast to FB1.
The three mycotoxins inhibit protein synthesis with respective IC50 of 5, 8.8 and 19 microM for DON, FB1 and ZEN confirming that protein synthesis is a specific target of DON.
DNA synthesis is inhibited by DON, ZEN and FB1 with respective IC50 of 1.7, 10 and 20 microM. However at higher concentrations DNA synthesis seems to be restored for FB1 and DON suggesting a promoter activity.
Altogether the potency of the three mycotoxins in macromolecules inhibition is DON>ZEN>FB1 in Caco-2 cells. It appears then that FB1 acts rather through lipid peroxidation while DON affects rather DNA and protein synthesis.
*
Nusuetrong P, Pengsuparp T, Meksuriyen D, Tanitsu M, Kikuchi H, Mizugaki M, Shimazu K, Oshima Y, Nakahata N, Yoshida M. Satratoxin H generates reactive oxygen species and lipid peroxides in PC12 cells. Biol Pharm Bull. 2008 Jun;31(6):1115-20. PMID: 18520041
Satratoxin H, a mycotoxin, is thought to induce apoptosis of PC12 cells through the activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) in a glutathione (GSH)-sensitive manner.
Satratoxin H increased reactive oxygen species (ROS) production and lipid peroxidation, as determined by malondialdehyde formation. These effects were attenuated by incubation of cells with GSH, suggesting that satratoxin H-induced increase in apoptosis of serum-deprived PC12 cells may be partially mediated through the generation of ROS.
*
Kovcikov Z, Ttrai E, Pieckov E, Tulinsk J, Pivovarov Z, Matausic-Pisl M, Kuricov M, Wsolov L. An in vitro study of the toxic effects of Stachybotrys chartarum metabolites on lung cells. Altern Lab Anim. 2007 Mar;35(1):47-52. PMID: 17411351
During a study of indoor fungal colonisation, several isolates of Stachybotrys chartarum were recovered, and the effects of metabolites from four isolates on lung epithelial Type II cells and alveolar macrophages were studied in vitro. All the isolates showed toxic effects on both cell types,
In Type II cells, the number of alkaline phosphatase positive cells was reduced, the pattern of Maclura pomifera agglutinin (MPA) binding was changed, and acid phosphatase activity in alveolar macrophages was diminished. In both cell types, the production of monocyte chemotactic protein-1 (MCP-1) and tumour necrosis factor-alpha (TNF-alpha) was changed, and parameters related to antioxidant status (superoxide dismutase, glutathione peroxidase, glutathione) were decreased.
*
Costa S, Schwaiger S, Cervellati R, Stuppner H, Speroni E, Guerra MC. In vitro evaluation of the chemoprotective action mechanisms of leontopodic acid against aflatoxin B1 and deoxynivalenol-induced cell damage. J Appl Toxicol. 2009 Jan;29(1):7-14. PMID: 18636399
Several in vitro studies showed that free radical scavengers possess chemopreventive properties against mycotoxin-induced cell damage which are at least partially associated with the induction of phase II detoxifying enzymes and antioxidant enzymes like glutathione S-transferase (GST) and glutathione peroxidase (GPx).
The aim of this project was to study the chemopreventive effects of leontopodic acid (LA), a potent natural occurring free radical scavenger isolated from the aerial parts of Leontopodium alpinum.
Cell viability and reactive oxygen species concentration were determined, and the effects of pre-treatment with LA on these parameters were investigated together with the GST and GPx activity as well as the concentration of reduced glutathione.
We hypothesize that the increase in detoxifying enzymes is probably the main mechanism of antioxidant mediated chemoprevention.
*
Rezar V, Frankic T, Narat M, Levart A, Salobir J. Dose-dependent effects of T-2 toxin on performance, lipid peroxidation, and genotoxicity in broiler chickens. Poult Sci. 2007 Jun;86(6):1155-60. PMID: 17495086
The results of the present study indicate that impaired performance, DNA fragmentation in spleen leukocytes, and elevated serum IgA levels induced by T-2 toxin are dose-dependent.
Based on our results, we could not confirm the hypothesis that oxidative stress is among the mechanisms by which T-2 toxin induces DNA fragmentation.
*
Dvorska JE, Pappas AC, Karadas F, Speake BK, Surai PF. Protective effect of modified glucomannans and organic selenium against antioxidant depletion in the chicken liver due to T-2 toxin-contaminated feed consumption. PMID: 17350343
The aim of this work was to assess the effect of T-2 toxin on the antioxidant status of the chicken and to study possible protective effects of modified glucomannan (Mycosorb) and organic selenium (Sel-Plex).
Inclusion of T-2 toxin in the chickens' diet (8.1 mg/kg for 21 days) was associated with significant decreases in the concentrations of selenium (Se)(by 32.2%), alpha-tocopherol (by 41.4%), total carotenoids (by 56.5%), ascorbic acid (by 43.5%) and reduced glutathione (by 56.3%) in the liver, as well as a decrease in the hepatic activity of Se-dependent glutathione peroxidase (Se-GSH-Px) (by 36.8%).
However, inclusion of modified glucomannans into the T-2 toxin-contaminated diet provided a partial protection against the detrimental effects of the mycotoxin on the antioxidant defences in the chicken liver.
*
Nusuetrong P, Yoshida M, Tanitsu MA, Kikuchi H, Mizugaki M, Shimazu K, Pengsuparp T, Meksuriyen D, Oshima Y, Nakahata N. Involvement of reactive oxygen species and stress-activated MAPKs in satratoxin H-induced apoptosis. Eur J Pharmacol. 2005 Jan 10;507(1-3):239-46. PMID: 15659314
Satratoxin H caused cytotoxicity, which was reflected from apoptosis determined by chromatin staining and flow cytometry. Satratoxin H stimulated the phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Pre-incubation with SB203580, a p38 MAPK inhibitor, or SP600125, a JNK inhibitor, but not PD98059, an ERK inhibitor, reduced satratoxin-induced cytotoxicity.
Co-incubation of cells with glutathione, N-acetyl-L-cysteine or glutathione reductase inhibited cytotoxicity and the phosphorylation of p38 MAPK induced by satratoxin H.
Our data suggest that satratoxin H-induced apoptosis in PC12 cells is dependent on the activation of p38 MAPK/JNK and the increase in reactive oxygen species.
*
Meissonnier GM, Laffitte J, Raymond I, Benoit E, Cossalter AM, Pinton P, Bertin G, Oswald IP, Galtier P. Subclinical doses of T-2 toxin impair acquired immune response and liver cytochrome P450 in pigs. Toxicology. 2008 May 2;247(1):46-54. PMID: 18355953
This study was designed to investigate the effect of subclinical doses of T-2 toxin on liver drug-metabolizing enzymes and the immune response.
Pigs fed 1324 or 2102microg T-2toxin/kg feed exhibited reduced anti-ovalbumin antibody production without significant alteration to specific lymphocyte proliferation.
The livers of pigs exposed to T-2 toxin presented normal cytochrome P450 content, UGT 1A and P450 2B, 2C or 3A protein expression, and glutathione- and UDP glucuronosyl-transferase activities.
However, P450 1A related activities (ethoxyresorufin O-deethylation and benzo-(a)-pyrene hydroxylation) were reduced for all pigs given T-2 toxin, with P450 1A protein expression decreased in pigs fed the highest dose. In addition T-2 toxin exposure reduced certain N-demethylase activities.
The results of this study confirm the immunotoxic properties of T-2 toxin, in particular toward the humoral immune response.
The reduction of monooxygenase activities, even though the liver presented no tissue lesion or lipid peroxidation, suggests possible deleterious interactions of T-2 toxin with these enzymes.
There is a lot of this research, so the project is going to take a bit more time to finish.
In the meantime, I'm going to post abstracts here.
The ones in this post are related to oxidative stress, which many CFS doctors (e.g. Dr. Cheney) now believe are a core part of this disease.
Best, Lisa
*
Markkanen Penttinen P, Pelkonen J, Tapanainen M, Mki-Paakkanen J, Jalava PI, Hirvonen MR. Co-cultivated damp building related microbes Streptomyces californicus and Stachybotrys chartarum induce immunotoxic and genotoxic responses via oxidative stress. Inhal Toxicol. 2009 Aug;21(10):857-67. PMID: 19459771
Oxidative stress has been proposed to be one mechanism behind the adverse health outcomes associated with living in a damp indoor environment. In the present study, the capability of damp building-related microbes Streptomyces californicus and Stachybotrys chartarum to induce oxidative stress was evaluated in vitro. In addition, the role of oxidative stress in provoking the detected cytotoxic, genotoxic, and inflammatory responses was studied by inhibiting the production of reactive oxygen species (ROS) using N-acetyl-l-cysteine (NAC). RAW264.7 macrophages were exposed in a dose- and time-dependent manner to the spores of co-cultivated S. californicus and S. chartarum, to their separately cultivated spore-mixture, or to the spores of these microbes alone. The intracellular peroxide production and cytotoxicity were measured by flow cytometric analysis, nitric oxide production was analyzed by the Griess method, DNA damage was determined by the comet assay, and cytokine production was measured by an immunochemical ELISA (enzyme-linked immunosorbent assay). All the studied microbial exposures triggered oxidative stress and subsequent cellular damage in RAW264.7 macrophages. The ROS scavenger, NAC, prevented growth arrest, apoptosis, DNA damage, and cytokine production induced by the co-culture since it reduced the intracellular level of ROS within macrophages. In contrast, the DNA damage and cell cycle arrest induced by the spores of S. californicus alone could not be prevented by NAC. Bioaerosol-induced oxidative stress in macrophages may be an important mechanism behind the frequent respiratory symptoms and diseases suffered by residents of moisture damaged buildings. Furthermore, microbial interactions during co-cultivation stimulate the production of highly toxic compound(s) which may significantly increase oxidative damage.
*
Wang H, Yadav JS. DNA damage, redox changes, and associated stress-inducible signaling events underlying the apoptosis and cytotoxicity in murine alveolar macrophage cell line MH-S by methanol-extracted Stachybotrys chartarum toxins. Toxicol Appl Pharmacol. 2006 Aug 1;214(3):297-308. PMID: 16476459
Spore-extracted toxins of the indoor mold Stachybotrys chartarum (SC) caused cytotoxicity (release of lactate dehydrogenase), inhibition of cell proliferation, and cell death in murine alveolar macrophage cell line MH-S in a dose- and time-dependent manner.
The apoptotic dose of SC toxins did not induce detectable nitric oxide and pro-inflammatory cytokines (IL-1beta, IL-6, and TNF-alpha) but showed exacerbated cytotoxicity in presence of a non-apoptotic dose of the known pro-inflammatory agent LPS (10 ng/ml).
Intracellular reduced glutathione (GSH) level showed a significant decrease beginning at 9 h of the toxin treatment whereas oxidized glutathione (GSSG) showed a corresponding significant increase, indicating a delayed onset of oxidative stress in the apoptosis process.
The toxin-treated macrophages accumulated p53, an indicator of DNA damage response, and showed activation of the stress-inducible MAP kinases, JNK, and p38
Chemical blocking of either p38 or p53 inhibited in part the SC toxin-induced apoptosis whereas blocking of JNK did not show any such effect.
*
Wang H, Yadav JS. Global gene expression changes underlying Stachybotrys chartarum toxin-induced apoptosis in murine alveolar macrophages: evidence of multiple signal transduction pathways. Apoptosis. 2007 Mar;12(3):535-48. PMID: 17186382
The overall mechanism(s) underlying macrophage apoptosis caused by the toxins of the indoor mold Stachybotrys chartarum (SC) are not yet understood.
The toxin-regulated genes corresponded to multiple cellular processes, including cell growth, proliferation and death, inflammatory/immune response, genotoxic stress and oxidative stress, and to the underlying multiple signal transduction pathways involving MAPK-, NF-kB-, TNF-, and p53-mediated signaling.
Transcription factor NF-kB showed dynamic temporal changes, characterized by an initial activation and a subsequent inhibition.
Up-regulation of a battery of DNA damage-responsive and DNA repair genes in the early stage of the treatment suggested a possible role of genotoxic stress in the initiation of apoptosis.
Simultaneous expression changes in both pro-survival genes and pro-apoptotic genes indicated the role of a critical balance between the two processes in SC toxin-induced apoptosis.
Taken together, the results imply that multiple signaling pathways underlie the SC toxin-induced apoptosis in alveolar macrophages.
*
Rakkestad KE, Skaar I, Ansteinsson VE, Solhaug A, Holme JA, Pestka JJ, Samuelsen JT, Dahlman HJ, Hongslo JK, Becher R. DNA damage and DNA damage responses in THP-1 monocytes after exposure to spores of either Stachybotrys chartarum or Aspergillus versicolor or to T-2 toxin. Toxicol Sci. 2010 May;115(1):140-55. PMID: 20150440
We have characterized cell death in THP-1 cells after exposure to heat-treated spores from satratoxin G-producing Stachybotrys chartarum isolate IBT 9631, atranone-producing S. chartarum isolate IBT 9634, and sterigmatocystin-producing Aspergillus versicolor isolate IBT 3781, as well as the trichothecenes T-2 and satratoxin G. Spores induced cell death within 3-6 h, with Stachybotrys appearing most potent.
IBT 9631 induced both apoptosis and necrosis, while IBT 9634 and IBT 3781 induced mostly necrosis. T-2 toxin and satratoxin G caused mainly apoptosis.
Comet assay +/- formamidopyrimidine DNA glycosylase showed that only the spore exposures induced early (3h) oxidative DNA damage. Likewise, only the spores increased the formation of reactive oxygen species (ROS), suggesting that spores as particles may induce ROS formation and oxidative DNA damage.
In conclusion, activation of Chk2 and H2AX correlated with spore- and toxin-induced apoptosis. For IBT 9631 and satratoxin G, additional factors may be involved in triggering apoptosis, most notably p38 activation.
*
Chaudhari M, Jayaraj R, Santhosh SR, Rao PV. Oxidative damage and gene expression profile of antioxidant enzymes after T-2 toxin exposure in mice. J Biochem Mol Toxicol. 2009 May;23(3):212-21. PMID: 19526462.
T-2 toxin showed significant alterations in hepatic alanine amino transferase, aspartate amino transferase, and lactate dehydrogenase.
Significant changes in hepatic lipid peroxidation, depletion of glutathione (GSH), and expression of heat shock protein-70 indicated oxidative damage.
We also evaluated the activity of antioxidant enzymes and compared the gene expression profile by quantitative real-time reverse transcriptase-polymerase chain reaction.
Except for glutathione reductase (GR), there was a significant increase in activity of glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase at 1 LD50 dose.
At 2 LD50 dose, SOD showed decrease in activity, whereas GST, GPx, and catalase showed significant increase.
In contrast, gene expression profile showed downregulation in GR, GPx, GST, and catalase at 1 LD50 dose. At 2 LD50 dose except GSH synthetase, all other genes were downregulated.
The results clearly show oxidative stress as one of the mechanisms of T-2 toxin-mediated toxicity.
*
Zhang X, Jiang L, Geng C, Cao J, Zhong L. The role of oxidative stress in deoxynivalenol-induced DNA damage in HepG2 cells. Toxicon. 2009 Sep 15;54(4):513-8. PMID: 19486909.
The aim of this study was to assess the role of oxidative stress in deoxynivalenol-induced DNA damage, using human hepatoma HepG2 cells.
In order to clarify the underlying mechanisms, we evaluated the level of reactive oxygen species (ROS) production with the 2,7-dichlorofluorescein diacetate (DCFH-DA) assay. Significant increase in the level of ROS was observed in HepG2 cells at a higher concentration (60 microM). The involvement of lipid peroxidation in the DNA damage of DON was confirmed by using immunoperoxidase staining for 8-hydroxydeoxyguanosine (8-OHdG) and by measuring levels of thiobarbituric acid-reactive substances (TBARS), the doses being 7.5-60 microM and 3.75-15 microM, respectively. These results indicate that the DNA damage induced by DON in HepG2 cells is probably related to the oxidative stress.
*
Borutova R, Faix S, Placha I, Gresakova L, Cobanova K, Leng L. Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers. Arch Anim Nutr. 2008 Aug;62(4):303-12. PMID: 18763624
Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg kg(-1), while Group 2 received DON and ZEA at 8.2 and 8.3 mg kg(-1), respectively.
Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma gamma-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and alpha-tocopherol in plasma were not affected by dietary mycotoxins.
Blood phagocytic activity was significantly depressed in Group 1 and 2.
These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.
*
Kouadio JH, Mobio TA, Baudrimont I, Moukha S, Dano SD, Creppy EE. Comparative study of cytotoxicity and oxidative stress induced by deoxynivalenol, zearalenone or fumonisin B1 in human intestinal cell line Caco-2. Toxicology. 2005 Sep 15;213(1-2):56-65. PMID: 16019124
Fusarium toxins such as, deoxynivalenol (DON), zearalenone (ZEN) and fumonisin B1 (FB1) have been shown to cause diverse toxic effects in animals and also suspected of disease causation in humans. From the literature and mechanistic point of view, DON binds to the ribosomal peptidyl-transferase and inhibits protein synthesis specifically and DNA synthesis consequently. ZEN known to be genotoxic, binds to 17-beta-estradiol receptors, induces lipid peroxidation, cell death and inhibits protein and DNA synthesis. FB1 disrupts sphingolipid metabolism, induces lipid peroxidation altering the cell membrane and causing cell death.
We intended to compare DON, ZEN and FB1 (1-150 microM) cytotoxic effect and the pathways leading to cell death and related to oxidative stress and macromolecules syntheses in a human intestinal cell line in order to tentatively classify them according to their respective potential toxicity.
The comparison reveals that all three mycotoxins bear, at variable degree, the capability of inducing lipid peroxidation (MDA production) and could be classified above 10 microM in decreasing potency order FB1>DON>ZEN.
This effect seems to be related to their common target that is the mitochondria as revealed by MTT test and seemingly not related to sphingoids accumulation concerning FB1.
DON and ZEN also adversely affect lysosomes in contrast to FB1.
The three mycotoxins inhibit protein synthesis with respective IC50 of 5, 8.8 and 19 microM for DON, FB1 and ZEN confirming that protein synthesis is a specific target of DON.
DNA synthesis is inhibited by DON, ZEN and FB1 with respective IC50 of 1.7, 10 and 20 microM. However at higher concentrations DNA synthesis seems to be restored for FB1 and DON suggesting a promoter activity.
Altogether the potency of the three mycotoxins in macromolecules inhibition is DON>ZEN>FB1 in Caco-2 cells. It appears then that FB1 acts rather through lipid peroxidation while DON affects rather DNA and protein synthesis.
*
Nusuetrong P, Pengsuparp T, Meksuriyen D, Tanitsu M, Kikuchi H, Mizugaki M, Shimazu K, Oshima Y, Nakahata N, Yoshida M. Satratoxin H generates reactive oxygen species and lipid peroxides in PC12 cells. Biol Pharm Bull. 2008 Jun;31(6):1115-20. PMID: 18520041
Satratoxin H, a mycotoxin, is thought to induce apoptosis of PC12 cells through the activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) in a glutathione (GSH)-sensitive manner.
Satratoxin H increased reactive oxygen species (ROS) production and lipid peroxidation, as determined by malondialdehyde formation. These effects were attenuated by incubation of cells with GSH, suggesting that satratoxin H-induced increase in apoptosis of serum-deprived PC12 cells may be partially mediated through the generation of ROS.
*
Kovcikov Z, Ttrai E, Pieckov E, Tulinsk J, Pivovarov Z, Matausic-Pisl M, Kuricov M, Wsolov L. An in vitro study of the toxic effects of Stachybotrys chartarum metabolites on lung cells. Altern Lab Anim. 2007 Mar;35(1):47-52. PMID: 17411351
During a study of indoor fungal colonisation, several isolates of Stachybotrys chartarum were recovered, and the effects of metabolites from four isolates on lung epithelial Type II cells and alveolar macrophages were studied in vitro. All the isolates showed toxic effects on both cell types,
In Type II cells, the number of alkaline phosphatase positive cells was reduced, the pattern of Maclura pomifera agglutinin (MPA) binding was changed, and acid phosphatase activity in alveolar macrophages was diminished. In both cell types, the production of monocyte chemotactic protein-1 (MCP-1) and tumour necrosis factor-alpha (TNF-alpha) was changed, and parameters related to antioxidant status (superoxide dismutase, glutathione peroxidase, glutathione) were decreased.
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Costa S, Schwaiger S, Cervellati R, Stuppner H, Speroni E, Guerra MC. In vitro evaluation of the chemoprotective action mechanisms of leontopodic acid against aflatoxin B1 and deoxynivalenol-induced cell damage. J Appl Toxicol. 2009 Jan;29(1):7-14. PMID: 18636399
Several in vitro studies showed that free radical scavengers possess chemopreventive properties against mycotoxin-induced cell damage which are at least partially associated with the induction of phase II detoxifying enzymes and antioxidant enzymes like glutathione S-transferase (GST) and glutathione peroxidase (GPx).
The aim of this project was to study the chemopreventive effects of leontopodic acid (LA), a potent natural occurring free radical scavenger isolated from the aerial parts of Leontopodium alpinum.
Cell viability and reactive oxygen species concentration were determined, and the effects of pre-treatment with LA on these parameters were investigated together with the GST and GPx activity as well as the concentration of reduced glutathione.
We hypothesize that the increase in detoxifying enzymes is probably the main mechanism of antioxidant mediated chemoprevention.
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Rezar V, Frankic T, Narat M, Levart A, Salobir J. Dose-dependent effects of T-2 toxin on performance, lipid peroxidation, and genotoxicity in broiler chickens. Poult Sci. 2007 Jun;86(6):1155-60. PMID: 17495086
The results of the present study indicate that impaired performance, DNA fragmentation in spleen leukocytes, and elevated serum IgA levels induced by T-2 toxin are dose-dependent.
Based on our results, we could not confirm the hypothesis that oxidative stress is among the mechanisms by which T-2 toxin induces DNA fragmentation.
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Dvorska JE, Pappas AC, Karadas F, Speake BK, Surai PF. Protective effect of modified glucomannans and organic selenium against antioxidant depletion in the chicken liver due to T-2 toxin-contaminated feed consumption. PMID: 17350343
The aim of this work was to assess the effect of T-2 toxin on the antioxidant status of the chicken and to study possible protective effects of modified glucomannan (Mycosorb) and organic selenium (Sel-Plex).
Inclusion of T-2 toxin in the chickens' diet (8.1 mg/kg for 21 days) was associated with significant decreases in the concentrations of selenium (Se)(by 32.2%), alpha-tocopherol (by 41.4%), total carotenoids (by 56.5%), ascorbic acid (by 43.5%) and reduced glutathione (by 56.3%) in the liver, as well as a decrease in the hepatic activity of Se-dependent glutathione peroxidase (Se-GSH-Px) (by 36.8%).
However, inclusion of modified glucomannans into the T-2 toxin-contaminated diet provided a partial protection against the detrimental effects of the mycotoxin on the antioxidant defences in the chicken liver.
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Nusuetrong P, Yoshida M, Tanitsu MA, Kikuchi H, Mizugaki M, Shimazu K, Pengsuparp T, Meksuriyen D, Oshima Y, Nakahata N. Involvement of reactive oxygen species and stress-activated MAPKs in satratoxin H-induced apoptosis. Eur J Pharmacol. 2005 Jan 10;507(1-3):239-46. PMID: 15659314
Satratoxin H caused cytotoxicity, which was reflected from apoptosis determined by chromatin staining and flow cytometry. Satratoxin H stimulated the phosphorylation of extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK). Pre-incubation with SB203580, a p38 MAPK inhibitor, or SP600125, a JNK inhibitor, but not PD98059, an ERK inhibitor, reduced satratoxin-induced cytotoxicity.
Co-incubation of cells with glutathione, N-acetyl-L-cysteine or glutathione reductase inhibited cytotoxicity and the phosphorylation of p38 MAPK induced by satratoxin H.
Our data suggest that satratoxin H-induced apoptosis in PC12 cells is dependent on the activation of p38 MAPK/JNK and the increase in reactive oxygen species.
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Meissonnier GM, Laffitte J, Raymond I, Benoit E, Cossalter AM, Pinton P, Bertin G, Oswald IP, Galtier P. Subclinical doses of T-2 toxin impair acquired immune response and liver cytochrome P450 in pigs. Toxicology. 2008 May 2;247(1):46-54. PMID: 18355953
This study was designed to investigate the effect of subclinical doses of T-2 toxin on liver drug-metabolizing enzymes and the immune response.
Pigs fed 1324 or 2102microg T-2toxin/kg feed exhibited reduced anti-ovalbumin antibody production without significant alteration to specific lymphocyte proliferation.
The livers of pigs exposed to T-2 toxin presented normal cytochrome P450 content, UGT 1A and P450 2B, 2C or 3A protein expression, and glutathione- and UDP glucuronosyl-transferase activities.
However, P450 1A related activities (ethoxyresorufin O-deethylation and benzo-(a)-pyrene hydroxylation) were reduced for all pigs given T-2 toxin, with P450 1A protein expression decreased in pigs fed the highest dose. In addition T-2 toxin exposure reduced certain N-demethylase activities.
The results of this study confirm the immunotoxic properties of T-2 toxin, in particular toward the humoral immune response.
The reduction of monooxygenase activities, even though the liver presented no tissue lesion or lipid peroxidation, suggests possible deleterious interactions of T-2 toxin with these enzymes.