Nucleotide excision repair of oxidised genomic DNA is not a source of urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine

Autor: David H. Phillips, Yusaku Nakabeppu, Agnieszka Siomek-Gorecka, Jie Zuo, Teruhisa Tsuzuki, Mark D. Evans, Margherita Bignami, Rajinder Singh, Daniel Gackowski, Mutsuo Sekiguchi, Rafal Rozalski, Alex Pines, Kunihiko Sakumi, Marcus S. Cooke, Leon H.F. Mullenders, Ryszard Olinski, Vilas Mistry
Rok vydání: 2016
Předmět:
Male
8-dihydro-2’-deoxyguanosine
0301 basic medicine
congenital
hereditary
and neonatal diseases and abnormalities
Xeroderma pigmentosum
DNA Repair
DNA repair
Gene Expression
Biology
Biochemistry
Cockayne syndrome
Mice
03 medical and health sciences
chemistry.chemical_compound
Physiology (medical)
medicine
Animals
oxidative stress
Deoxyguanosine
Cockayne Syndrome
skin and connective tissue diseases
8-oxo-7
Mice
Knockout
Xeroderma Pigmentosum
Deoxyguanine Nucleotides
nutritional and metabolic diseases
DNA
DNA oxidation
nucleotide excision repair
medicine.disease
Phosphoric Monoester Hydrolases
urine
Xeroderma Pigmentosum Group A Protein
MTH1
Mice
Inbred C57BL
Disease Models
Animal
Oxidative Stress
genomic DNA
030104 developmental biology
chemistry
8-Hydroxy-2'-Deoxyguanosine
transcription-coupled repair
Female
Biomarkers
DNA Damage
Nucleotide excision repair
Zdroj: Free Radical Biology and Medicine. 99:385-391
ISSN: 0891-5849
DOI: 10.1016/j.freeradbiomed.2016.08.018
Popis: The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Urinary 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodGuo) is a widely measured biomarker of oxidative stress. It has been commonly assumed to be a product of DNA repair, and therefore reflective of DNA oxidation. However, the source of urinary 8-oxodGuo is not understood, although potential confounding contributions from cell turnover and diet have been ruled out. Clearly it is critical to understand the precise biological origins of this important biomarker, so that the target molecule that is oxidised can be identified, and the significance of its excretion can be interpreted fully. In the present study we aimed to assess the contributions of nucleotide excision repair (NER), by both the global genome NER (GG-NER) and transcription-coupled NER (TC-NER) pathways, and sanitisation of the dGTP pool (e.g. via the activity of the MTH1 protein), on the production of 8-oxodGuo, using selected genetically-modified mice. In xeroderma pigmentosum A (XPA) mice, in which GG-NER and TC-NER are both defective, the urinary 8-oxodGuo data were unequivocal in ruling out a contribution from NER. In line with the XPA data, the production of urinary 8-oxodGuo was not affected in the xeroderma pigmentosum C mice, specifically excluding a role of the GG-NER pathway. The bulk of the literature supports the mechanism that the NER proteins are responsible for removing damage to the transcribed strand of DNA via TC-NER, and on this basis we also examined Cockayne Syndrome mice, which have a functional loss of TC-NER. These mice showed no difference in urinary 8-oxodGuo excretion, compared to wild type, demonstrating that TC-NER does not contribute to urinary 8-oxodGuo levels. These findings call into question whether genomic DNA is the primary source of urinary 8-oxodGuo, which would largely exclude it as a biomarker of DNA oxidation. The urinary 8-oxodGuo levels from the MTH1 mice (both knock-out and hMTH1-Tg) were not significantly different to the wild-type mice. We suggest that these findings are due to redundancy in the process, and that other enzymes substitute for the lack of MTH1, however the present study cannot determine whether or not the 2’-deoxyribonucleotide pool is the source of urinary 8-oxodGuo. On the basis of the above, urinary 8-oxodGuo is most accurately defined as a non-invasive biomarker of oxidative stress, derived from oxidatively generated damage to 2’-deoxyguanosine.
Databáze: OpenAIRE
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