The Organic Selenium Compound Selenomethionine Modulates Bleomycin-Induced DNA Damage and Repair in Human Leukocytes

This is an Accepted Version of the published document. This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s12011-009-8407-9[Abstract] The objective of this work was to evaluate the effects of selenomethionine (SeMet) on the induction, repair, and persistence of DNA damage in human leukocytes challenged with bleomycin (BLM). Comet assay was used to determine DNA strand breaks and hOGG1 for the specific recognition of oxidative damage. Leukocytes were (A) stimulated with phytohemagglutinin, (B) damaged with BLM, and (C) incubated to allow DNA repair. Comet assay was performed after each phase. SeMet (50 μM) was supplemented either during phase A, B, or C, or AB, or ABC. Treatment with SeMet decreased BLM-induced stand breaks when added during phase AB. Results obtained after the repair period indicate that SeMet favors repair of DNA damage especially when applied during phase AB. The comparison between DNA damage before and after repair showed that BLM-induced damage was repaired better in the presence of SeMet. Our results showed antigenotoxic effect of SeMet on BLM-induced DNA and also on repair and persistence of this damage when applied before and simultaneously with BLM.This work was funded by a grant from the Xunta de Galicia (INCITE08PXIB106155PR). V. Valdiglesias was supported by a fellowship from the University of A CoruñaGalicia. Xunta; INCITE08PXIB106155P

Induction of Oxidative DNA Damage by the Marine Toxin Okadaic Acid Depends on Human Cell Type

This is a manuscript versión of the article.[Abstract] The marine toxin okadaic acid (OA) is the main representative of diarrhoeic shellfish poisoning (DSP) toxins. Its ingestion induces nausea, vomiting, diarrhoea and abdominal ache. It has also been found to trigger cellular and molecular effects at low concentrations. Its mechanism of action has not been described yet. Results of a previous study showed that OA can induce cytotoxic and genotoxic effects, both directly and indirectly, and modulations in DNA repair processes in three different types of human cells (leukocytes, SHSY5Y neuroblastoma and HepG2 cells). These effects varied depending on the type of cell and the concentration employed (Valdiglesias et al., 2010). On that basis, the ability of OA to induce oxidative DNA damage on the same cell types was investigated in the present study. To this end, the antioxidant enzymes catalase and N-acetylcysteine, and the human DNA- glycosylase hOGG1 were used in combination with the alkaline Comet assay. The cells were treated with a range of OA concentrations (5–1000 nM) in the presence and absence of S9 fraction. The results of this study showed that OA induces oxidative DNA damage directly in leukocytes, directly and indirectly in SHSY5Y cells, while it does not induce oxidative DNA damage in HepG2 cells. Combining the outcomes of both studies, the data showed that OA induces both cytotoxicity and genotoxicity, including DNA strand breaks and oxidative DNA damage, in the cells evaluated. However, the extent of these effects are cell type dependent.This work was funded by a grant from the Xunta de Galicia (INCITE08PXIB106155PR). V. Valdiglesias was supported by a fellowship from the University of A CoruñaGalicia. Xunta; INCITE08PXIB106155P

Assessment of Okadaic Acid Effects on Cytotoxicity, DNA Damage and DNA Repair in Human Cells

This is a manuscript version of the article.[Abstract] Okadaic acid (OA) is a phycotoxin produced by several types of dinoflagellates causing diarrheic shellfish poisoning (DSP) in humans. Symptoms induced by DSP toxins are mainly gastrointestinal, but the intoxication does not appear to be fatal. Despite this, this toxin presents a potential threat to human health even at concentrations too low to induce acute toxicity, since previous animal studies have shown that OA has very potent tumour promoting activity. However, its concrete action mechanism has not been described yet and the results reported with regard to OA cytotoxicity and genotoxicity are often contradictory. In the present study, the genotoxic and cytotoxic effects of OA on three different types of human cells (peripheral blood leukocytes, HepG2 hepatoma cells, and SHSY5Y neuroblastoma cells) were evaluated. Cells were treated with a range of OA concentrations in the presence and absence of S9 fraction, and MTT test and Comet assay were performed in order to evaluate cytotoxicity and genotoxicity, respectively. The possible effects of OA on DNA repair were also studied by means of the DNA repair competence assay, using bleomycin as DNA damage inductor. Treatment with OA in absence of S9 fraction induced not statistically significant decrease in cell viability and significant increase in DNA damage in all cell types at the highest concentrations investigated. However, only SHSY5Y cells showed OA induced genotoxic and cytotoxic effects in presence of S9 fraction. Furthermore, we found that OA can induce modulations in DNA repair processes when exposure was performed prior to BLM treatment, in co-exposure, or during the subsequent DNA repair process.This work was funded by a grant from the Xunta de Galicia (INCITE08PXIB106155PR). V. Valdiglesias was supported by a fellowship from the University of A CoruñaGalicia. Xunta; INCITE08PXIB106155P

Identification of differentially expressed genes in SHSY5Y cells exposed to okadaic acid by suppression subtractive hybridization

<p>Abstract</p> <p>Background</p> <p>Okadaic acid (OA), a toxin produced by several dinoflagellate species is responsible for frequent food poisonings associated to shellfish consumption. Although several studies have documented the OA effects on different processes such as cell transformation, apoptosis, DNA repair or embryogenesis, the molecular mechanistic basis for these and other effects is not completely understood and the number of controversial data on OA is increasing in the literature.</p> <p>Results</p> <p>In this study, we used suppression subtractive hybridization in SHSY5Y cells to identify genes that are differentially expressed after OA exposure for different times (3, 24 and 48 h). A total of 247 subtracted clones which shared high homology with known genes were isolated. Among these, 5 specific genes associated with cytoskeleton and neurotransmission processes (NEFM, TUBB, SEPT7, SYT4 and NPY) were selected to confirm their expression levels by real-time PCR. Significant down-regulation of these genes was obtained at the short term (3 and 24 h OA exposure), excepting for NEFM, but their expression was similar to the controls at 48 h.</p> <p>Conclusions</p> <p>From all the obtained genes, 114 genes were up-regulated and 133 were down-regulated. Based on the NCBI GenBank and Gene Ontology databases, most of these genes are involved in relevant cell functions such as metabolism, transport, translation, signal transduction and cell cycle. After quantitative PCR analysis, the observed underexpression of the selected genes could underlie the previously reported OA-induced cytoskeleton disruption, neurotransmission alterations and <it>in vivo </it>neurotoxic effects. The basal expression levels obtained at 48 h suggested that surviving cells were able to recover from OA-caused gene expression alterations.</p

Cytogenetic Effects Induced by Prestige Oil on Human Populations: The Role of Polymorphisms in Genes Involved in Metabolism and DNA Repair

This is a manuscript version of the article.[Abstract] The spill from the oil tanker Prestige (NW Spain, November 2002) was perhaps the biggest ecological disaster that happened worldwide in the last decades. As a consequence of this catastrophe a general concern led to a huge mobilization of human and technical resources. Given that no information was reported in the scientific literature regarding to the chronic repercussions to human health of exposure to oil spills, a pilot study was performed by our group revealing some increased genotoxic effects in the subjects exposed to the oil during cleaning activities. Due to the seriousness of the results, we extended our study comprising a larger population and including an extensive evaluation of the main polymorphic sites in metabolizing and DNA-repair genes. General increases in micronucleus (MN) frequency and decreases in the proliferation index were observed in individuals with longer time of exposure. Age was a significant predictor of MN frequency. CYP1A1 3′-UTR, EPHX1 codons 113 and 139, GSTP1, GSTM1 and GSTT1 metabolic polymorphisms, and XRCC3 codon 241 and XPD codon 751 repair polymorphisms influenced cytogenetic damage levels. In view of these results, it seems essential to pay more attention to the chronic human health effects of exposure to oil and to focus new studies on such a relevant but overlooked public health field that involves a large number of people all over the world.This work was partially funded by a grant from the Fundación Arao through the intervention of Dr. Juan Jesús Gestal and Dr. Ernesto Smyth, and by the University of A Coruña. B. Pérez-Cadahía and V. Valdiglesias were supported by fellowships from the University of A Coruña

Biomonitoring of Human Exposure to Prestige Oil: Effects on DNA and Endocrine Parameters

Since 1960, about 400 tankers spilled more than 377765 tons of oil, with the Prestige accident (Galician coast, NW Spain, November 2002) the most recent. Taking into account the consistent large number of individuals exposed to oil that exists all over the world, it seems surprising the absence in the literature of studies focused on the chronic effects of this exposure on human health. In this work we evaluated the level of DNA damage by means of comet assay, and the potential endocrine alterations (prolactin and cortisol) caused by Prestige oil exposure in a population of 180 individuals, classified in 3 groups according to the tasks performed, and 60 controls. Heavy metals in blood were determined as exposure biomarkers, obtaining significant increases of aluminum, nickel and lead in the exposed groups as compared to controls. Higher levels of genetic damage and endocrine alterations were also observed in the exposed population. DNA damage levels were influenced by age, sex, and the use of protective clothes, and prolactin concentrations by the last two factors. Surprisingly, the use of mask did not seem to protect individuals from genetic or endocrine alterations. Moreover, polymorphisms in genes encoding for the main enzymes involved in the metabolism of oil components were analyzed as susceptibility biomarkers. CYP1A1-3′UTR and EPHX1 codons 113 and 139 variant alleles were related to higher damage levels, while lower DNA damage was observed in GSTM1 and GSTT1 null individuals

Analysis of Four Polymorphisms Located at the Promoter of the Estrogen Receptor Alpha ESR1 Gene in a Population With Gender Incongruence

[Abstract] Introduction: Gender incongruence defines a state in which individuals feel discrepancy between the sex assigned at birth and their gender. Some of these people make a social transition from male to female (transwomen) or from female to male (trans men). By contrast, the word cisgender describes a person whose gender identity is consistent with their sex assigned at birth. Aim: To analyze the implication of the estrogen receptor a gene (ESR1) in the genetic basis of gender incongruence. Main Outcome Measures: Polymorphisms rs9478245, rs3138774, rs2234693, rs9340799. Method: We carried out the analysis of 4 polymorphisms located at the promoter of the ESR1 gene (C1 ¼ rs9478245, C2 ¼ rs3138774, C3 ¼ rs2234693, and C4 ¼ rs9340799) in a population of 273 trans women, 226 trans men, and 537 cis gender controls. For SNP polymorphisms, the allele and genotype frequencies were analyzed by c2 test. The strength of the SNP associations with gender incongruence was measured by binary logistic regression. For the STR polymorphism, the mean number of repeats were analyzed by the ManneWhitney U test. Measurement of linkage disequilibrium and haplotype frequencies were also performed. Results: The C2 median repeats were shorter in the trans men population. Genotypes S/S and S/L for the C2 polymorphism were overrepresented in the trans men group (P ¼ .012 and P ¼ .003 respectively). We also found overtransmission of the A/A genotype (C4) in the trans men population (P ¼ .017), while the A/G genotype (C4) was subrepresented (P ¼ .009]. The analyzed polymorphisms were in linkage disequilibrium. In the trans men population, the T(C1)-L(C2)-C(C3)-A(C4) haplotype was overrepresented (P ¼ .019) while the T(C1)-L(C2)-C(C3)-G(C4) was subrepresented (P ¼ .005). Conclusion: The ESR1 is associated with gender incongruence in the trans men populationThis work was supported by grants: ED431B 019/02 (EP), PGC2018-094919-B-C21 (AG), PGC2018-094919-B-C22 (RF), and FPU 15/02558 (JCC)Xunta de Galicia; ED431B 019/0

Is salivary chromogranin A a valid psychological stress biomarker during sensory stimulation in people with advanced dementia?

[Abstract] Salivary chromogranin A (sCgA) is gaining attention as a biomarker of psychological stress. The objective of this work was to determine whether individualized music intervention and multisensory stimulation environment (MSSE) in a Snoezelen room produce changes in sCgA in severely demented older patients, and to assess the possible existence of differences in sCgA levels between the two types of interventions. Older adults with severe dementia (n = 22) were randomly assigned to two intervention groups. They participated in MSSE or individualized music interventions in 30-min weekly sessions for 16 weeks. Levels of sCgA were evaluated before and after a session, or 30-min interval, at four different time points: before starting the trial, in the middle and end of the intervention period, and two months later. Comparison of sCgA values obtained after each session with those obtained before (or at the same hour in before trial and follow-up samplings) showed no significant differences either in the individualized music or in the MSSE group at any sampling time. Comparison between the two types of interventions, both before and after each session, in the four sampling times, did not produce any significant difference either. Furthermore, no significant correlation was obtained between agitation, anxiety, cognitive function, and dementia severity with sCgA levels. In conclusion, despite beneficial effects of both individualized music and MSSE interventions being previously reported on neuropsychiatric outcomes for older patients with dementia, sCgA seems to not be a good indicator of these benefits.Xunta de Galicia; GPC2013-058Xunta de Galicia; GPC2014/08