Levels of DNA damage represent the dynamics between damage formation and removal. Therefore, to better interpret human biomonitoring studies with DNA damage endpoints, an individual's ability to recognize and properly remove DNA damage should be characterized. Relatively few studies have included DNA repair as a biomarker and therefore, assembling and analyzing a pooled database of studies with data on base excision repair (BER) was one of the goals of hCOMET (EU-COST CA15132). A group of approximately 1911 individuals, was gathered from 8 laboratories which run population studies with the comet-based in vitro DNA repair assay. BER incision activity data were normalized and subsequently correlated with various host factors. BER was found to be significantly higher in women. Although it is generally accepted that age is inversely related to DNA repair, no overall effect of age was found, but sex differences were most pronounced in the oldest quartile (>61 years). No effect of smoking or occupational exposures was found. A body mass index (BMI) above 25 kg/m2 was related to higher levels of BER. However, when BMI exceeded 35 kg/m2, repair incision activity was significantly lower. Finally, higher BER incision activity was related to lower levels of DNA damage detected by the comet assay in combination with formamidopyrimidine DNA glycosylase (Fpg), which is in line with the fact that oxidatively damaged DNA is repaired by BER. These data indicate that BER plays a role in modulating the steady-state level of DNA damage that is detected in molecular epidemiological studies and should therefore be considered as a parallel endpoint in future studies.
- Klíčová slova
- BMI, Base excision repair, Biomarker, Comet assay, DNA repair, Oxidatively damaged DNA,
- MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
- epidemiologické studie MeSH
- kometový test MeSH
- lidé středního věku MeSH
- lidé MeSH
- oprava DNA * genetika MeSH
- poškození DNA * MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- DNA-formamidopyrimidinglykosylasa MeSH
The extensive development of nanotechnologies and nanomaterials poses a number of questions to toxicologists about the potential health risks of exposure to nanoparticles (NP). In this study, we analysed DNA damage in the leukocytes of 20 workers who were long-term exposed (18 ± 10 years) to NP in their working environment. Blood samples were collected in September 2016, before and after a shift, to assess (i) the chronic effects of NP on DNA (pre-shift samples) and (ii) the acute effects of exposure during the shift (the difference between pre- and post-shift samples). The samples from matched controls were taken in parallel with workers before the shift. Leukocytes were isolated from heparinised blood on a Ficoll gradient. The enzyme-modified comet assay (DNA formamido-pyrimidine-glycosylase and endonuclease III) demonstrated a considerable increase of both single- and double-strand breaks in DNA (DNA-SB) and oxidised bases when compared with the controls (2.4× and 2×, respectively). Acute exposure induced a further increase of DNA-SB. The welding and smelting of nanocomposites represented a higher genotoxic risk than milling and grinding of nanocomposite surfaces. Obesity appeared to be a factor contributing to an increased risk of oxidative damage to DNA. The data also indicated a higher susceptibility of males vs. females to NP exposure. The study was repeated in September 2017. The results exhibited similar trend, but the levels of DNA damage in the exposed subjects were lower compared to previous year. This was probably associated with lower exposure to NP in consequence of changes in nanomaterial composition and working operations. The further study involving also monitoring of personal exposures to NP is necessary to identify (i) the main aerosol components responsible for genotoxic effects in workers handling nanocomposites and (ii) the primary cause of gender differences in response to NP action.
- MeSH
- deoxyribonukleasa (pyrimidinový dimer) MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
- DNA účinky léků metabolismus MeSH
- dospělí MeSH
- kometový test MeSH
- leukocyty účinky léků metabolismus MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mutageny MeSH
- nanokompozity toxicita MeSH
- oxidační stres MeSH
- poškození DNA * MeSH
- pracovní expozice škodlivé účinky MeSH
- proteiny z Escherichia coli MeSH
- sexuální faktory MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- deoxyribonukleasa (pyrimidinový dimer) MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
- DNA MeSH
- mutageny MeSH
- NTH protein, E coli MeSH Prohlížeč
- proteiny z Escherichia coli MeSH
Bacterial MutM is a DNA repair glycosylase removing DNA damage generated from oxidative stress and, therefore, preventing mutations and genomic instability. MutM belongs to the Fpg/Nei family of prokaryotic enzymes sharing structural and functional similarities with their eukaryotic counterparts, for example, NEIL1-NEIL3. Here, we present two crystal structures of MutM from pathogenic Neisseria meningitidis: a MutM holoenzyme and MutM bound to DNA. The free enzyme exists in an open conformation, while upon binding to DNA, both the enzyme and DNA undergo substantial structural changes and domain rearrangement. Our data show that not only NEI glycosylases but also the MutMs undergo dramatic conformational changes. Moreover, crystallographic data support the previously published observations that MutM enzymes are rather flexible and dynamic molecules.
- Klíčová slova
- Neisseria meningitidis, DNA repair, Fpg/Nei, MutM, base excision DNA repair,
- MeSH
- bakteriální proteiny chemie metabolismus MeSH
- DNA bakterií chemie metabolismus MeSH
- DNA-formamidopyrimidinglykosylasa chemie metabolismus MeSH
- krystalografie rentgenová MeSH
- Neisseria meningitidis enzymologie MeSH
- proteinové domény MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bakteriální proteiny MeSH
- DNA bakterií MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
Single cell gel electrophoresis, also known as the comet assay, is widely used for the detection and measurement of DNA strand breaks. With the addition of a step in which DNA is incubated with specific endonucleases recognising damaged bases, these lesions can be measured, too. In the standard protocol, electrophoresis is carried out at high pH. If, instead, electrophoresis is in neutral buffer, the effect of DNA damage seems to be much reduced--either because alkaline conditions are needed to reveal certain lesions, or because the effect of the same number of breaks on DNA migration is greater at high pH. A lower sensitivity can be useful in some circumstances, as it extends the range of DNA damage levels over which the assay can be used. Here we compare the performance of standard and modified techniques with a variety of DNA-damaging agents and offer possible explanations for the differences in behaviour of DNA under alternative electrophoretic conditions.
- MeSH
- chinoliziny farmakologie MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
- elektroforéza v agarovém gelu metody MeSH
- exodeoxyribonukleasy metabolismus MeSH
- Fabaceae genetika MeSH
- HeLa buňky účinky léků MeSH
- koncentrace vodíkových iontů MeSH
- léčivé rostliny MeSH
- lidé MeSH
- methylmethansulfonát farmakologie MeSH
- N-glykosylhydrolasy metabolismus MeSH
- poškození DNA * účinky léků MeSH
- pufry MeSH
- pyrimidinové dimery analýza MeSH
- pyrrolidiny farmakologie MeSH
- senzitivita a specificita MeSH
- vitamin K farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- chinoliziny MeSH
- DNA-formamidopyrimidinglykosylasa MeSH
- exodeoxyribonuclease III MeSH Prohlížeč
- exodeoxyribonukleasy MeSH
- methylmethansulfonát MeSH
- N-glykosylhydrolasy MeSH
- pufry MeSH
- pyrimidinové dimery MeSH
- pyrrolidiny MeSH
- Ro 19-8022 MeSH Prohlížeč
- vitamin K MeSH
