Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.677
Filtrar
1.
Ecotoxicol Environ Saf ; 205: 111283, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32977282

RESUMO

Fine particulate matter (PM2.5) airborne pollution increases the risk of chronic respiratory diseases, such as idiopathic pulmonary fibrosis (IPF), which is characterized by non-specific inflammation of the interstitial lung and extensive deposition of collagen fibers. Type 2 alveolar epithelial cells (AEC2s) are alveolar stem cells in the adult lung that contribute to the lung repair process through complex signaling. Our previous studies demonstrated that OGG1, a kind of DNA repair enzyme, have a critical role in protecting cells from oxidative damage and apoptosis induced by PM2.5, but the contribution of OGG1 in proliferation and self-renewal of AEC2s is not known. Here, we constructed OGG1-/-mice to test the effect and mechanism of OGG1 on PM2.5-induced pulmonary fibrosis and injury in vivo. We detected proliferation and self-renewal of OGG1 overexpression or OGG1 knockout AEC2s after PM2.5 injury by flow cytometry and clone formation. We observed that knockout of OGG1 aggravated pulmonary fibrosis, oxidative stress, and AEC2 cell death in PM2.5-injured mice. In addition, OGG1 is required for the proliferation and renewal of AEC2s after PM2.5 injury. Overexpression of OGG1 promotes the proliferation and self-renewal of AEC2s by inhibiting PM2.5-mediated oxidative stress and NF-κB signaling hyperactivation in vitro. Furthermore, NF-κB inhibitors promoted proliferation and self-renewal of OGG1-deficient AEC2s cells after PM2.5 injury, and attenuated PM2.5-induced pulmonary fibrosis and injury in mice. These data establish OGG1 as a regulator of NF-κB signal that serves to regulate AEC2 cell proliferation and self-renewal, and suggest a mechanism that inhibition of the NF-κB signaling pathway may represent a potential therapeutic strategy for IPF patients with low-expression of OGG1.


Assuntos
Poluentes Atmosféricos/toxicidade , Células Epiteliais Alveolares/efeitos dos fármacos , Autorrenovação Celular/genética , DNA Glicosilases/metabolismo , Material Particulado/toxicidade , Fibrose Pulmonar/induzido quimicamente , Células-Tronco/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/patologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , DNA Glicosilases/genética , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Pulmão/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/genética , Fibrose Pulmonar/genética , Fibrose Pulmonar/patologia , Transdução de Sinais , Células-Tronco/metabolismo , Células-Tronco/patologia
2.
Proc Natl Acad Sci U S A ; 117(36): 21889-21895, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32820079

RESUMO

DNA glycosylase is responsible for repairing DNA damage to maintain the genome stability and integrity. However, how glycosylase can efficiently and accurately recognize DNA lesions across the enormous DNA genome remains elusive. It has been hypothesized that glycosylase translocates along the DNA by alternating between a fast but low-accuracy diffusion mode and a slow but high-accuracy mode when searching for DNA lesions. However, the slow mode has not been successfully characterized due to the limitation in the spatial and temporal resolutions of current experimental techniques. Using a newly developed scanning fluorescence resonance energy transfer (FRET)-fluorescence correlation spectroscopy (FCS) platform, we were able to observe both slow and fast modes of glycosylase AlkD translocating on double-stranded DNA (dsDNA), reaching the temporal resolution of microsecond and spatial resolution of subnanometer. The underlying molecular mechanism of the slow mode was further elucidated by Markov state model built from extensive all-atom molecular dynamics simulations. We found that in the slow mode, AlkD follows an asymmetric diffusion pathway, i.e., rotation followed by translation. Furthermore, the essential role of Y27 in AlkD diffusion dynamics was identified both experimentally and computationally. Our results provided mechanistic insights on how conformational dynamics of AlkD-dsDNA complex coordinate different diffusion modes to accomplish the search for DNA lesions with high efficiency and accuracy. We anticipate that the mechanism adopted by AlkD to search for DNA lesions could be a general one utilized by other glycosylases and DNA binding proteins.


Assuntos
Bacillus cereus/genética , Proteínas de Bactérias/química , DNA Glicosilases/química , Bacillus cereus/química , Bacillus cereus/enzimologia , Bacillus cereus/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Reparo do DNA , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Bacteriano/metabolismo , Transferência Ressonante de Energia de Fluorescência , Cinética , Cadeias de Markov , Simulação de Dinâmica Molecular , Espectrometria de Fluorescência , Especificidade por Substrato
3.
Environ Sci Pollut Res Int ; 27(35): 43786-43799, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32740834

RESUMO

DNA damage may develop at any dose of ionizing radiation. DNA damage activates pathways that regulate cell growth and division or coordinate its replication and repair. The repair pathways, base excision repair (BER) and single-strand break repair (SSBR), can repair such damages efficiently and maintain genome integrity. Loss of this repair process or alteration of its control will be associated with serious outcomes for cells and individuals. This study aimed to determine the relationship between XRCC1 (Arg194Trp, Arg280His, and Arg399Gln), OGG1 (Ser326Cys), and XRCC3 (Thr241Met) SNPs and DNA damage and to identify high-risk individuals with reduced DNA repair capacity. This case-control study was conducted on 80 subjects; 50 subjects working in Clinical Oncology and Nuclear Medicine Department in Assiut University Hospital along with 30 controls. A total of 1 mL blood samples were collected for Single-Cell Gel Electrophoresis Technique (Comet Assay) for detection of DNA damage in those subjects. A total of 3 mL fresh blood samples were collected and analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based technique. DNA damage detected by comet test was significantly high in IR-exposed workers than control. Statistically high significant difference was found in exposed subjects versus control subjects regarding the frequencies of the variant alleles of hOGG1326, XRCC1280 & 399, and XRCC3241. The level of DNA damage was not affected by OGG1326 SNPs when comparing subjects of wild genotype with those of (pooled) variants either in the exposed staff or in the control group while XRCC1280, 399 and XRCC3241 variant alleles had an influence on the studied DNA damage biomarker. Moreover, genotyping distribution pattern was highly variable in relation to gender. The present study indicated a relationship between DNA damage detected by comet test and single nucleotide polymorphisms in genes coding for DNA certain repair enzymes. Individuals occupationally exposed to low doses of ionizing radiation could be at great risk and more susceptible to the increased DNA damage if they have inherited genetic polymorphism.


Assuntos
DNA Glicosilases , Estudos de Casos e Controles , Dano ao DNA , DNA Glicosilases/genética , Reparo do DNA/genética , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética
4.
Ecotoxicol Environ Saf ; 202: 110962, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32800233

RESUMO

Chronic exposure to fluoride (F) beyond the permissible limit (1.5 ppm) is known to cause detrimental health effects by induction of oxidative stress-mediated DNA damage overpowering the DNA repair machinery. In the present study, we assessed F induced oxidative stress through monitoring biochemical parameters and looked into the effect of chronic F exposure on two crucial DNA repair genes Ogg1 and Rad51 having important role against ROS induced DNA damages. To address this issue, we exposed Swiss albino mice to an environmentally relevant concentration of fluoride (15 ppm NaF) for 8 months. Results revealed histoarchitectural damages in liver, brain, kidney and spleen. Depletion of GSH, increase in lipid peroxidation and catalase activity in liver and brain confirmed the generation of oxidative stress. qRT-PCR result showed that expressions of Ogg1 and Rad51 were altered after F exposure in the affected organs. Promoter hypermethylation was associated with the downregulation of Rad51. F-induced DNA damage and the compromised DNA repair machinery triggered intrinsic pathway of apoptosis in liver and brain. The present study indicates the possible association of epigenetic regulation with F induced neurotoxicity.


Assuntos
Dano ao DNA , DNA Glicosilases/genética , Reparo do DNA , Epigênese Genética/efeitos dos fármacos , Fluoretos/toxicidade , Rad51 Recombinase/genética , Animais , Apoptose/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Encéfalo/patologia , Relação Dose-Resposta a Droga , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Camundongos , Estresse Oxidativo/efeitos dos fármacos
5.
Nucleic Acids Res ; 48(16): 9082-9097, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32710616

RESUMO

One of the most abundant DNA lesions induced by oxidative stress is the highly mutagenic 8-oxoguanine (8-oxoG), which is specifically recognized by 8-oxoguanine DNA glycosylase 1 (OGG1) to initiate its repair. How DNA glycosylases find small non-helix-distorting DNA lesions amongst millions of bases packaged in the chromatin-based architecture of the genome remains an open question. Here, we used a high-throughput siRNA screening to identify factors involved in the recognition of 8-oxoG by OGG1. We show that cohesin and mediator subunits are required for re-localization of OGG1 and other base excision repair factors to chromatin upon oxidative stress. The association of OGG1 with euchromatin is necessary for the removal of 8-oxoG. Mediator subunits CDK8 and MED12 bind to chromatin and interact with OGG1 in response to oxidative stress, suggesting they participate in the recruitment of the DNA glycosylase. The oxidative stress-induced association between the cohesin and mediator complexes and OGG1 reveals an unsuspected function of those complexes in the maintenance of genomic stability.


Assuntos
Cromatina/genética , DNA Glicosilases/genética , Reparo do DNA/genética , Guanina/análogos & derivados , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Eucromatina/genética , Instabilidade Genômica/genética , Guanina/metabolismo , Células HeLa , Humanos , Estresse Oxidativo/genética , RNA Interferente Pequeno/genética , Transfecção
6.
Mutat Res ; 853: 503170, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32522350

RESUMO

We examined possible early-effect biomarkers and polymorphisms of susceptibility in primary school children living near the Atoyac River in central México, which receives waste from multiple industries. We observed a significant increase in micronucleated reticulocytes associated with the oxidative stress index (OSI) and the OGG1 GG (S326C) genotype, and a significant decrease of reticulocytes carrying the transferrin receptor, inversely correlated with OSI.


Assuntos
DNA Glicosilases/genética , Poluição Ambiental/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Polimorfismo Genético/efeitos dos fármacos , Reticulócitos/efeitos dos fármacos , Adolescente , Biomarcadores/metabolismo , Criança , Feminino , Genótipo , Humanos , Masculino , Testes para Micronúcleos/métodos
7.
Toxicol Lett ; 332: 27-35, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32585298

RESUMO

Reactive oxygen species (ROS) within the cell are rapidly detoxified by antioxidants such as glutathione. Depletion of glutathione will therefore increase levels of intracellular ROS, which can lead to oxidative DNA damage and the induction of apoptosis. The working hypothesis was that Ogg1 null mouse embryonic fibroblasts (mOgg1-/- MEFs) would be more sensitive in response to GSH depletion due to their deficiency in the removal of the oxidative DNA modification, 8-oxo-7,8-dihydroguanine (8-oxoG). Following GSH depletion, an increase in intracellular ROS and a subsequent induction of apoptosis was measured in mOgg1-/- MEFs; as expected. Unexpectedly, an elevated basal level of ROS was identified in mOgg1-/- MEFs compared to wild type MEFs; which we suggest is partly due to the differential expression of key anti-oxidant genes. The elevated basal ROS levels in mOgg1-/- MEFs were not accompanied by a deficiency in ATP production or a large increase in 8-oxoG levels. Although 8-oxoG levels did increase following GSH depletion in mOgg1-/- MEFs; this increase was significantly lower than observed following treatment with a non-toxic dose of hydrogen peroxide. Reconstitution of Ogg1 into mOgg1-/- MEFs resulted in an increased viability following glutathione depletion, however this rescue did not differ between a repair-proficient and a repair-impaired variant of Ogg1. The data indicates that induction of apoptosis in response to oxidative stress in mOgg1-/- MEFs is independent of DNA damage and OGG1-initiated DNA repair.


Assuntos
Apoptose/efeitos dos fármacos , Dano ao DNA , DNA Glicosilases/genética , Fibroblastos/efeitos dos fármacos , Glutationa/metabolismo , Trifosfato de Adenosina/biossíntese , Animais , Butionina Sulfoximina/farmacologia , Reparo do DNA/efeitos dos fármacos , Reparo do DNA/genética , Inibidores Enzimáticos/farmacologia , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Knockout , Mitocôndrias/efeitos dos fármacos , Oxidantes/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
8.
Oncology ; 98(8): 583-588, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32521533

RESUMO

BACKGROUND: Gastric cancer (GC) is one of the leading causes of cancer death in China, while the nature of genetic factors related to GC has not been well-studied. OBJECTIVES: To assess the inherited genetic factors regarding pathogenic germline mutations in Chinese GC population. METHODS: Genomic profiling of DNA was performed through next-generation sequencing with 381 cancer-related genes on tissue from patients with GC between January 1, 2017, and May 7, 2019. RESULTS: 470 GC patients were included for analysis. A total of 28 (6.0%) patients were identified to harbor 25 different pathogenic or very likely pathogenic germline mutations in 15 genes. The variants fell most frequently in BRCA2 (n = 6, 1.28%), CHEK2 (n = 5, 1.06%), MUTYH (n = 3, 0.64%), CDH1 (n = 2, 0.43%), and ATM (n = 2, 0.43%). Of all the germline-mutated genes, 66.7% (n = 10) lay in the DNA damage repair pathways. Seven patients were identified to have a high TMB status, among whom two were also identified as MSI-H. Overall, 20 out of the 28 patients (71.4%) carried clinically actionable mutations. CONCLUSIONS: Our study has depicted the spectrum of pathogenic germline mutations in Chinese GC patients, which may provide valuable clues for the assessment of the genetic susceptibility and clinical management in GC.


Assuntos
Mutação em Linhagem Germinativa , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/genética , Idoso , Proteína BRCA2/genética , Quinase do Ponto de Checagem 2/genética , China/epidemiologia , Dano ao DNA/genética , DNA Glicosilases/genética , Feminino , Predisposição Genética para Doença , Humanos , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Neoplasias Gástricas/patologia
9.
Nat Commun ; 11(1): 3088, 2020 06 18.
Artigo em Inglês | MEDLINE | ID: mdl-32555206

RESUMO

DNA double-strand break repair by homologous recombination begins with nucleolytic resection of the 5' DNA strand at the break ends. Long-range resection is catalyzed by EXO1 and BLM-DNA2, which likely have to navigate through ribonucleotides and damaged bases. Here, we show that a short stretch of ribonucleotides at the 5' terminus stimulates resection by EXO1. Ribonucleotides within a 5' flap are resistant to cleavage by DNA2, and extended RNA:DNA hybrids inhibit both strand separation by BLM and resection by EXO1. Moreover, 8-oxo-guanine impedes EXO1 but enhances resection by BLM-DNA2, and an apurinic/apyrimidinic site stimulates resection by BLM-DNA2 and DNA strand unwinding by BLM. Accordingly, depletion of OGG1 or APE1 leads to greater dependence of DNA resection on DNA2. Importantly, RNase H2A deficiency impairs resection overall, which we attribute to the accumulation of long RNA:DNA hybrids at DNA ends. Our results help explain why eukaryotic cells possess multiple resection nucleases.


Assuntos
Quebras de DNA de Cadeia Dupla , Ribonucleotídeos/genética , Ribonucleotídeos/metabolismo , Western Blotting , Linhagem Celular Tumoral , DNA Glicosilases/genética , Enzimas Reparadoras do DNA/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Exodesoxirribonucleases/genética , Imunofluorescência , Recombinação Homóloga/genética , Humanos , RecQ Helicases/genética , Recombinação Genética/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo
10.
Bull Cancer ; 107(5): 586-600, 2020 May.
Artigo em Francês | MEDLINE | ID: mdl-32362383

RESUMO

MUTYH-associated polyposis (MUTYH-associated polyposis, MAP) is an autosomal recessive inheritance disorder related to bi-allelic constitutional pathogenic variants of the MUTYH gene which was first described in 2002. In 2011, a group of French experts composed of clinicians and biologists, performed a summary of the available data on this condition and drew up recommendations concerning the indications and the modalities of molecular analysis of the MUTYH gene in index cases and their relatives, as well as the management of affected individuals. In view of recent developments, some recommendations have become obsolete, in particular with regard to the molecular analysis strategy since MUTYH gene has been recently included in a consensus panel of 14 genes predisposing to colorectal cancer. This led us to revise all the points of the previous expertise. We report here the revised version of this work which successively considers the phenotype and the tumor risks associated with this genotype, the differential diagnoses, the indication criteria and the strategy of the molecular analysis and the recommendations for the management of affected individuals. We also discuss the phenotype and the tumor risks associated with mono-allelic pathogenic variants of MUTYH gene.


Assuntos
Polipose Adenomatosa do Colo/genética , DNA Glicosilases/genética , Polipose Adenomatosa do Colo/diagnóstico , Polipose Adenomatosa do Colo/terapia , Alelos , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Neoplasias Colorretais/terapia , DNA Glicosilases/análise , Diagnóstico Diferencial , Neoplasias do Sistema Digestório/genética , Saúde da Família , França , Predisposição Genética para Doença , Humanos , Neoplasias/genética , Fenótipo
11.
Life Sci ; 254: 117755, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32437792

RESUMO

AIMS: Efficient memory formation in rodents depends on adult neurogenesis in the subgranular zone of the hippocampus, and mounting evidence suggests that deficiencies in initiating repair of oxidatively induced DNA damage may impair neurogenesis. Hence, we aimed to determine whether loss of the DNA glycosylase, endonuclease VIII-like 1 (Neil1), affects hippocampal neurogenesis and memory performance in young-adult mice. MAIN METHODS: Eight-week-old male wild-type and Neil1-deficient (Neil1-/-) mice were treated with bromodeoxyuridine to track neuronal proliferation and differentiation. A neurosphere formation assay was further used to measure neuroprogenitor proliferative capacity. Hippocampus-related memory functions were assessed with Y-maze spontaneous alternation and novel object recognition tests. KEY FINDINGS: Young-adult male Neil1-/- mice exhibited diminished adult hippocampal neurogenesis in the dentate gyrus, probably as a result of poor survival of newly proliferated neurons. Furthermore, the Y-maze spontaneous alternation and novel object recognition tests respectively revealed that Neil1 deficiency impairs spatial and non-spatial hippocampus-related memory functions. We also found that expression of p53, a central regulator of apoptosis, was upregulated in the dentate gyrus of Neil1-/- mice, while the level of ß-catenin, a key cell survival molecule, was downregulated. SIGNIFICANCE: The DNA glycosylase, Neil1, promotes successful hippocampal neurogenesis and learning and memory in young-adult mice.


Assuntos
Cognição/fisiologia , DNA Glicosilases/deficiência , Hipocampo/enzimologia , Memória/fisiologia , Neurônios/enzimologia , Animais , Diferenciação Celular/fisiologia , Sobrevivência Celular/fisiologia , Disfunção Cognitiva/enzimologia , Disfunção Cognitiva/patologia , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Giro Denteado/citologia , Giro Denteado/enzimologia , Hipocampo/citologia , Hipocampo/metabolismo , Aprendizagem/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neurogênese/fisiologia , Neurônios/citologia
12.
Free Radic Res ; 54(4): 280-292, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32326776

RESUMO

Background: Large epidemiological studies point towards a link between the incidence of arterial hypertension, ischaemic heart disease, metabolic disease and exposure to traffic noise, supporting the role of noise exposure as an independent cardiovascular risk factor. We characterised the underlying molecular mechanisms leading to noise-dependent adverse effects on the vasculature and myocardium in an animal model of aircraft noise exposure and identified oxidative stress and inflammation as central players in mediating vascular and cardiac dysfunction. Here, we studied the impact of noise-induced oxidative DNA damage on vascular function in DNA-repair deficient 8-oxoguanine glycosylase knockout (Ogg1-/-) mice.Methods and results: Noise exposure (peak sound levels of 85 and mean sound level of 72 dB(A) applied for 4d) caused oxidative DNA damage (8-oxoguanine) and enhanced NOX-2 expression in C57BL/6 mice with synergistic increases in Ogg1-/- mice (shown by immunohistochemistry). A similar pattern was found for oxidative burst of blood leukocytes and other markers of oxidative stress (4-hydroxynonenal, 3-nitrotyrosine) and inflammation (cyclooxygenase-2). We observed additive impairment of noise exposure and genetic Ogg1 deficiency on endothelium-independent relaxation (nitroglycerine), which may be due to exacerbated oxidative DNA damage leading to leukocyte activation and oxidative aldehyde dehydrogenase inhibition.Conclusions: The finding that chronic noise exposure causes oxidative DNA damage in mice is worrisome since these potential mutagenic lesions could contribute to cancer progression. Human field studies have to demonstrate whether oxidative DNA damage is also found in urban populations with high levels of noise exposure as recently shown for workers with high occupational noise exposure.


Assuntos
Aeronaves , Dano ao DNA , DNA Glicosilases/deficiência , Exposição Ambiental/efeitos adversos , Nitratos/metabolismo , Ruído/efeitos adversos , Explosão Respiratória/fisiologia , Animais , DNA Glicosilases/genética , Camundongos , Camundongos Knockout , Estresse Oxidativo/fisiologia
13.
Nucleic Acids Res ; 48(9): 5106-5118, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32232412

RESUMO

R.PabI is a restriction DNA glycosylase that recognizes the sequence 5'-GTAC-3' and hydrolyses the N-glycosidic bond of adenine in the recognition sequence. R.PabI drastically bends and unwinds the recognition sequence of double-stranded DNA (dsDNA) and flips the adenine and guanine bases in the recognition sequence into the catalytic and recognition sites on the protein surface. In this study, we determined the crystal structure of the R.PabI-dsDNA complex in which the dsDNA is drastically bent by the binding of R.PabI but the base pairs are not unwound. This structure is predicted to be important for the indirect readout of the recognition sequence by R.PabI. In the complex structure, wedge loops of the R.PabI dimer are inserted into the minor groove of dsDNA to stabilize the deformed dsDNA structure. A base stacking is distorted between the two wedge-inserted regions. R.PabI is predicted to utilize the distorted base stacking for the detection of the recognition sequence.


Assuntos
DNA Glicosilases/química , DNA/química , DNA/metabolismo , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Enzimas de Restrição do DNA , Modelos Moleculares , Mutação , Conformação de Ácido Nucleico , Ligação Proteica
14.
Mutat Res ; 852: 503167, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32265040

RESUMO

Chronic kidney disease (CKD) is a multifactorial disorder with an important genetic component, and several studies have demonstrated potential associations with allelic variants. In addition, CKD patients are also characterized by high levels of genomic damage. Nevertheless, no studies have established relationships between DNA damage, or genomic instability present in CKD patients, and gene polymorphisms. To fill in this gap, the potential role of polymorphisms in genes involved in base excision repair (OGG1, rs1052133; MUTYH, rs3219489; XRCC1, rs25487), nucleotide excision repair (ERCC2/XPD, rs1799793, rs171140, rs13181; ERCC4, rs3136166); phase II metabolism (GSTP1, rs749174; GSTO1, rs2164624; GSTO2, rs156697), and antioxidant enzymes (SOD1, rs17880135, rs1041740, rs202446; SOD2, rs4880; CAT, rs1001179; GPX1, rs17080528; GPX3, rs870406: GPX4, rs713041) were inquired. In addition, some genes involved in CKD (AGT, rs5050; GLO1, rs386572987; SHROOM3, rs17319721) were also evaluated. The genomic damage, the genomic instability, and oxidative damage were evaluated by using the micronucleus and the comet assay in 589 donors (415 CKD patients and 174 controls). Our results showed significant associations between genomic damage and genes directly involved in DNA repair pathways (XRCC1, and ERCC2), and with genes encoding for antioxidant enzymes (SOD1 and GPX1). GSTO2, as a gene involved in phase II metabolism, and MUTYH showed also an association with genomic instability. Interestingly, the three genes associated with CKD (AGT, GLO1, and SHROOM3) showed associations with both the high levels of oxidatively damaged DNA and genomic instability. These results support our view that genomic instability can be considered a biomarker of the CKD status.


Assuntos
Angiotensinogênio/genética , Reparo do DNA , Instabilidade Genômica , Lactoilglutationa Liase/genética , Proteínas dos Microfilamentos/genética , Insuficiência Renal Crônica/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiotensinogênio/metabolismo , Estudos de Casos e Controles , Ensaio Cometa , Dano ao DNA , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Feminino , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Predisposição Genética para Doença , Genoma Humano , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Humanos , Lactoilglutationa Liase/metabolismo , Masculino , Proteínas dos Microfilamentos/metabolismo , Testes para Micronúcleos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Insuficiência Renal Crônica/metabolismo , Insuficiência Renal Crônica/fisiopatologia , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/metabolismo , Proteína Grupo D do Xeroderma Pigmentoso/genética , Proteína Grupo D do Xeroderma Pigmentoso/metabolismo
15.
BMC Cancer ; 20(1): 234, 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32192442

RESUMO

BACKGROUND: Despite conflicting results, considerable evidence suggests the association between single nucleotide polymorphisms in MTHFR, XRCC1 and OGG1 genes and, risk of developing breast cancer. Here a case-control study is reported, including 135 breat cancer patients and 112 healthy women, all representative of Northern Sardinian population. METHODS: Polymerase chain reaction/restriction fragment length polymorphism method was used to determine the genotypes of five polymorphisms: MTHFR C677T (rs1801133) and A1298C (rs1801131), XRCC1 Arg194Trp (rs1799782) and Arg399Gln (rs25487) and OGG1 Ser326Cys (rs1052133). Allelic, genotypic and haplotype association analyses with disease risk and clinicopathological parameters were performed. RESULTS: A nominally significant association with breast cancer risk was observed for MTHFR C677T polymorphism heterozygous genotype in the codominant model (OR: 0.57, 95% CI: 0.32-1.00, p = 0.049) and for Cys/Cys genotype of the OGG1 Ser326Cys polymorphism in the recessive model (OR: 0.23, 95% CI: 0.05-1.11, p = 0.0465). No significant differences were found at genotype-level for A1298C polymorphism of the MTHFR gene and Arg194Trp and Arg399Gln of the XRCC1 gene. Furthermore, the OGG1 and XRCC1 rs25487 polymorphisms were nominally associated with PgR, Her2 status and with sporadic breast cancer, respectively. CONCLUSIONS: Based on genetic characteristics of individuals included in this study, results suggest that MTHFR CT and OGG1 Cys/Cys genotypes have a protective effect that may have an influence on breast cancer risk in a representative Northern Sardinian population.


Assuntos
Neoplasias da Mama/genética , DNA Glicosilases/genética , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo de Nucleotídeo Único , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética , Estudos de Casos e Controles , Feminino , Estudos de Associação Genética , Predisposição Genética para Doença , Técnicas de Genotipagem , Haplótipos , Humanos , Itália , Pessoa de Meia-Idade
16.
Biochem Biophys Res Commun ; 525(3): 806-811, 2020 05 07.
Artigo em Inglês | MEDLINE | ID: mdl-32164943

RESUMO

Helicobacter pylori, a pathogenic bacterium that colonizes in the human stomach, harbors DNA repair genes to counter the gastric environment during chronic infection. In addition, H. pylori adapts to the host environment by undergoing antigenic phase variation caused by genomic mutations. The emergence of mutations in nucleotide sequences is one of the major factors underlying drug resistance and genetic diversity in bacteria. However, it is not clear how DNA repair genes contribute to driving the genetic change of H. pylori during chronic infection. To elucidate the physiological roles of DNA repair genes, we generated DNA repair-deficient strains of H. pylori (ΔuvrA, ΔuvrB, ΔruvA, Δnth, ΔmutY, ΔmutS, and Δung). We performed susceptibility testing to rifampicin in vitro and found that ΔmutY exhibited the highest mutation frequency among the mutants. The number of bacteria colonizing the stomach was significantly lower with ΔmutY strain compared with wild-type strains in a Mongolian gerbil model of H. pylori infection. Furthermore, we performed a genomic sequence analysis of the strains isolated from the Mongolian gerbil stomachs eight weeks after infection. We found that the isolated ΔmutY strains exhibited a high frequency of spontaneous G:C to T:A mutations. However, the frequency of phase variations in the ΔmutY strain was almost similar to the wild-type strain. These results suggest that MutY may play a role in modes of gastric environmental adaptation distinct from phase variation.


Assuntos
Adaptação Fisiológica , DNA Glicosilases/genética , Helicobacter pylori/genética , Mutação/genética , Estômago/microbiologia , Animais , Proteínas de Bactérias/genética , Reparo do DNA/genética , Modelos Animais de Doenças , Gerbillinae , Infecções por Helicobacter/microbiologia , Helicobacter pylori/crescimento & desenvolvimento , Taxa de Mutação , NF-kappa B/metabolismo
17.
Artigo em Inglês | MEDLINE | ID: mdl-32209025

RESUMO

Alveolar epithelial cell (AEC) apoptosis, arising from mitochondrial dysfunction and mitophagy defects, is important in mediating idiopathic pulmonary fibrosis (IPF). Our group established a role for the mitochondrial (mt) DNA base excision repair enzyme, 8-oxoguanine-DNA glycosylase 1 (mtOGG1), in preventing oxidant-induced AEC mtDNA damage and apoptosis and showed that OGG1-deficient mice have increased lung fibrosis. Herein, we determined whether mice overexpressing the mtOGG1 transgene (mtOgg1tg) are protected against lung fibrosis and whether AEC mtOGG1 preservation of mtDNA integrity mitigates phosphatase and tensin homolog-induced putative kinase 1 (PINK1) deficiency and apoptosis. Compared with wild type (WT), mtOgg1tg mice have diminished asbestos- and bleomycin-induced pulmonary fibrosis that was accompanied by reduced lung and AEC mtDNA damage and apoptosis. Asbestos and H2O2 promote the MLE-12 cell PINK1 deficiency, as assessed by reductions in the expression of PINK1 mRNA and mitochondrial protein expression. Compared with WT, Pink1-knockout (Pink1-KO) mice are more susceptible to asbestos-induced lung fibrosis and have increased lung and alveolar type II (AT2) cell mtDNA damage and apoptosis. AT2 cells from Pink1-KO mice and PINK1-silenced (siRNA) MLE-12 cells have increased mtDNA damage that is augmented by oxidative stress. Interestingly, mtOGG1 overexpression attenuates oxidant-induced MLE-12 cell mtDNA damage and apoptosis despite PINK1 silencing. mtDNA damage is increased in the lungs of patients with IPF as compared with controls. Collectively, these findings suggest that mtOGG1 maintenance of AEC mtDNA is crucial for preventing PINK1 deficiency that promotes apoptosis and lung fibrosis. Given the key role of AEC apoptosis in pulmonary fibrosis, strategies aimed at preserving AT2 cell mtDNA integrity may be an innovative target.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Asbestose/genética , DNA Glicosilases/genética , Pulmão/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Proteínas Quinases/genética , Fibrose Pulmonar/genética , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/patologia , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Asbestos/administração & dosagem , Asbestose/etiologia , Asbestose/metabolismo , Asbestose/patologia , Bleomicina/administração & dosagem , Dano ao DNA , DNA Glicosilases/deficiência , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Feminino , Regulação da Expressão Gênica , Peróxido de Hidrogênio/farmacologia , Pulmão/metabolismo , Pulmão/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mitocôndrias/metabolismo , Cultura Primária de Células , Proteínas Quinases/metabolismo , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/metabolismo , Fibrose Pulmonar/patologia , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Titânio/administração & dosagem
18.
World Neurosurg ; 138: 535-540.e8, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32113992

RESUMO

BACKGROUND: Cerebral cavernous malformations (CCMs) are vascular capillary anomalies with a dysfunctional endothelial adherent junction profile, depicting hemorrhage and epilepsy as the main clinical features. With the advent of an increasingly personalized medicine, better comprehension of genetic mechanisms behind CCM represents an important key in the management of the patients and risk rating in relatives. In this context, genetic factors that might influence clinical expressiveness of CCM need to be identified. CASE DESCRIPTION: A 33-year-old woman harboring multiple CCM lesions with a CCM1 mutational profile already being treated conservatively for a right mesial temporal lobe CCM presented with refractory seizures. Magnetic resonance imaging showed no bleeding in the lesion, and the patient was submitted to complete resection of the CCM. Histopathology of the CCM samples depicted an extensive inflammatory reaction and colocalization of CD20+ and CD68+ cells. Genetic analyses of the patient and her mother demonstrated a novel CCM1 (KRIT1) frameshift mutation (c.1661_1662insT; p.Leu554PhefsTer14). Furthermore, variants in CD14 (rs778588), TLR-4 (rs10759930), SOD2 (rs4880), APEX1 (rs1130409), and OGG1 (rs1052133), known as polymorphisms related to disease aggressiveness, were detected in the patient and not in her oligosymptomatic mother harboring the same CCM1 mutation. CONCLUSIONS: Heterogeneity of clinical manifestations among individuals with familial CCM with the same genotype adds mechanistic involvement of modifier factors as phenotypic markers. We describe a novel CCM1/KRIT1 familial mutation in which the coexistence of genetic variants in inflammation and oxidative stress may be related to variable expressiveness of the disease.


Assuntos
Mutação da Fase de Leitura , Hemangioma Cavernoso do Sistema Nervoso Central/genética , Proteína KRIT1/genética , Adulto , Anticonvulsivantes/uso terapêutico , Brasil , DNA Glicosilases/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Feminino , Genótipo , Hemangioma Cavernoso do Sistema Nervoso Central/complicações , Hemangioma Cavernoso do Sistema Nervoso Central/diagnóstico por imagem , Hemangioma Cavernoso do Sistema Nervoso Central/cirurgia , Humanos , Inflamação/genética , Receptores de Lipopolissacarídeos/genética , Imagem por Ressonância Magnética , Mães , Estresse Oxidativo/genética , Fenótipo , Convulsões/tratamento farmacológico , Convulsões/etiologia , Índice de Gravidade de Doença , Superóxido Dismutase/genética , Receptor 4 Toll-Like/genética
19.
Sci Rep ; 10(1): 5136, 2020 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-32198476

RESUMO

Genetic polymorphisms of NEIL1 and NEIL2 maybe change protein function, and increased carcinogenesis. In this study, seven NEIL1 SNPs and three NEIL2 SNPs were selected. 400 CSCCs, 400 CIN III, and 1200 normal healthy controls were genotyped by mismatch amplification PCR. mRNA and protein expression of NEIL2 was measured in 92 freshly-obtained CSCC tumor tissues. The association between homozygote CC genotype of NEIL2 rs804270 with susceptible risk was gradually increased in CIN III (OR = 1.44) and CSCC (OR = 2.22). Carriers of C-allele (GC + CC) at rs804270 had a high risk of CSCC (OR = 1.46). The heterozygote GT genotype of rs8191664 was also closely related to the higher risk of CINIII (OR = 1.59) and CSCC (OR = 2.54). Carriers of T-allele (GT + TT) at rs8191664 had a high risk for CIN III (OR = 1.55) and CSCC (OR = 2.34). The genotypes of NEIL2 rs804270 (G/C) and rs8191664 (G/T) that were related to the higher risk for CIN III were CC-GG (OR = 1.42) and CC-GT (OR = 2.07). More notably, there was a greater risk for CSCC with the GC-GT (OR = 1.91), CC-GG (OR = 1.67), and CC-GT (OR = 6.18) genotypes. NEIL2 mRNA expression in CSCCs with the rs804270-CC genotype was lower expression than those in CSCCs with the rs804270-GG and rs804270-GC genotypes. Similarly, NEIL2 protein expression was significantly decreased in CSCCs with the rs804270-CC genotype. In summary, the two genetic polymorphisms (rs804270 and rs8191664) of NEIL2 gene were significantly associated to the increased susceptibility of CIN III or CSCC. This increased susceptibility maybe due to altered NEIL2 repair activity through altered protein expression, or changed structure of the functional domain. The genotypes of GC-GT, CC-GG, and CC-GT of rs804270 and rs8191664 of NEIL2 gene could act as a genetic predictive biomarker of susceptibility to CIN III and CSCC.


Assuntos
Neoplasia Intraepitelial Cervical/genética , DNA Glicosilases/genética , Reparo do DNA/genética , DNA Liase (Sítios Apurínicos ou Apirimidínicos)/genética , Neoplasias do Colo do Útero/genética , Adulto , Alphapapillomavirus/isolamento & purificação , Biomarcadores Tumorais/genética , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/genética , China/epidemiologia , Feminino , Frequência do Gene/genética , Estudos de Associação Genética , Predisposição Genética para Doença/genética , Humanos , Infecções por Papillomavirus/virologia , Polimorfismo de Nucleotídeo Único/genética , Risco , Neoplasias do Colo do Útero/epidemiologia
20.
Int J Radiat Biol ; 96(6): 734-739, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32149571

RESUMO

Background: Single Nucleotide Polymorphisms (SNPs) at DNA repair genes are considered as potential biomarkers of radio-sensitivity. The coastal belt of Kerala in south west India has a patchy distribution of monazite in its beach sand that contains Th-232 and its decay products. Thus, radiation levels in this area vary from <1.0mGy to 45.0mGy/year. The areas with external gamma radiation dose >1.5mGy/year are considered as High-Level Natural Radiation Areas (HLNRA) and ≤ 1.5mGy/year are Normal Level Natural Radiation Area (NLNRA).Objective: In the present study, an attempt was made to evaluate the influence of chronic low dose radiation exposure on DNA repair gene polymorphisms in NLNRA and HLNRA population of Kerala coast.Materials and methods: Genomic DNA was isolated from venous blood samples of 246 random, healthy individuals (NLNRA, N = 104; HLNRA, N = 142) and genotyping of five SNPs such as X-ray repair cross complementing 1(XRCC1 Arg399Gln), X-ray repair cross complementing 3 (XRCC3 Thr241Met], Protein kinase, DNA-activated, catalytic subunit (PRKDC) (X-ray repair cross-complementing group 7, XRCC7 G/T), nei like DNA glycosylase 1 (NEIL1 G/T) and DNA ligase 1 (LIG1 A/C) was carried out using PCR based restriction fragment length polymorphism (PCR-RFLP) followed by silver staining.Results: Our results showed no significant difference in genotype frequencies in HLNRA vs NLNRA at three of the five SNPs studied i.e. XRCC1 Arg399Gln (χ2(2) = 5.85, p = .054), XRCC3 Thr241Met (χ2(1) = 0.71, p = .339), PRKDC (XRCC7 G/T) (χ2(2) = 3.72, p = .156), whereas significant difference was observed at NEIL1 G/T (χ2(2) =8.71, p = .013) and LIG1 A/C (χ2(2) = 7.66, p = .022). The odds of heterozygote to homozygote genotypes in HLNRA relative to NLNRA at XRCC1 Arg399Gln (OR = 1.96, 95% CI: 1.13-3.40), XRCC3 Thr241Met (OR = 0.73, 95% CI: 0.41-1.31), PRKDC (XRCC7 G/T), (OR = 0.81; 95% CI: 0.48-1.38), NEIL1 G/T (OR = 0.54; 95% CI: 0.31-0.96) and LIG1 A/C (OR = 1.62; 95% CI: 0.97-2.69) was also not significantly different in HLNRA vs NLNRA, except at XRCC1 and NEIL1.Conclusion: The genotype frequencies at three of these SNPs i.e. XRCC1 Arg399Gln, XRCC3 Thr241Met and PRKDC (XRCC7 G/T) were similar, whereas NEIL1 G/T and LIG1 A/C showed significant difference between HLNRA and NLNRA population. However, further research using more number of SNPs in a larger cohort is required in this study area.


Assuntos
Reparo do DNA/genética , Reparo do DNA/efeitos da radiação , Polimorfismo de Nucleotídeo Único , Doses de Radiação , DNA Glicosilases/genética , DNA Ligase Dependente de ATP/genética , Proteína Quinase Ativada por DNA/genética , Proteínas de Ligação a DNA/genética , Humanos , Índia , Fatores de Tempo , Proteína 1 Complementadora Cruzada de Reparo de Raio-X/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA