Contrasting genome-wide distribution of 8-hydroxyguanine and acrolein-modified adenine during oxidative stress-induced renal carcinogenesis.

Oxidative stress is a persistent threat to the genome and is associated with major causes of human mortality, including cancer, atherosclerosis, and aging. Here we established a method to generate libraries of genomic DNA fragments containing oxidatively modified bases by using specific monoclonal antibodies to immunoprecipitate enzyme-digested genome DNA. We applied this technique to two different base modifications, 8-hydroxyguanine and 1,N6-propanoadenine (acrotein-Ade), in a ferric nitrilotriacetate-induced murine renal carcinogenesis model. Renal cortical genomic DNA derived from 10- to 12-week-old male C57BL/6 mice, of untreated control or 6 hours after intraperitoneal injection of 3 mg iron/kg ferric nitrilotriacetate, was enzyme digested, immunoprecipitated, cloned, and mapped to each chromosome. The results revealed that distribution of the two modified bases was not random but differed in terms of chromosomes, gene size, and expression, which could be partially explained by chromosomal territory. In the wild-type mice, low GC content areas were more likely to harbor the two modified bases. Knockout of OGG1, a repair enzyme for genomic 8-hydroxyguanine, increased the amounts of acrolein-Ade as determined by quantitative polymerase chain reaction analyses. This versatile technique would introduce a novel research area as a high-throughput screening method for critical genomic loci under oxidative stress.

Quantitative determination of urinary 8-hydroxy-2'-deoxyguanosine level in healthy Japanese volunteers.

8-hydroxy-2'-deoxyguanosine (8-OHdG), as a measure of oxidative stress, was measured in healthy Japanese volunteers using an ELISA (New 8-OHdG Check, JICA). Analysis of daytime spot urine of 83 healthy male subjects and smoking habit, exercise and age revealed significant correlation only between the urinary level of 8-OHdG and age. As the inter-individual variation of 8-OHdG of the daytime spot urine was relatively high, we next determined inter-and intra-individual variation of 5 healthy volunteers. The levels of 8-OHdG/creatinine in morning spot urine significantly correlated with 8-OHdG levels in 24-h pool urine. Thus, a morning spot urine sample can be used for the measurement of 8-OHdG instead of inconvenient 24-h sampling.

Comparison of an oxidative stress biomarker "urinary8-hydroxy-2'-deoxyguanosine," between smokers and non-smokers.

A great deal of effort has been made on the effect of oxidative stress for smokers. What seems to be lacking, however, is its evidence. Analyzing 1076 participants (age 35.9 +/- 12.9, urinary8-OHdG Mean +/- S.D., 11.4 +/- 6.7, n = 1076), our study found the significant increase in a biomarker of DNA damage urinary 8-OHdG/creatinine among smokers (7.75 +/- 2.8 ng/ml x CRE (n = 154) and 7.36 +/- 2.5 ng/ml x CRE (n = 627) (p < 0.05), Relative Risk = 2.9 (1.4-6.2) sex and age +/- 2 matching 105 male smokers and non-smokers. There was no significance on the comparison between female smokers and non-smokers. Smokers have significantly decreased serum alpha-tocopherol (1012 +/- 455, 1152 +/- 857, p < 0.03). The amount of serum ascorbate did not change. Smokers lowered serum HDL-cholesterol compared to non-smokers (59.3 +/- 11.8, 63.9 +/- 13.3, p < 0.05). The result of oxidative stress profile (OSP) also indicated that the increase of oxidative stress to smokers (p < 0.05). The calculated value of oxygen radical absorbance capacity (ORAC) of the meal for subjects was 1600 ORAC units.

FasL-induced downregulation of CD28 expression on jurkat cells in vitro is associated with activation of caspases.

Ligation of CD28, which is present on the majority of CD4(+)T cells, promotes proliferation and immune responses. However, expression of CD28 declines with aging, and apoptosis may contribute to this decline. We have investigated the molecular mechanism underlying the decrease in CD28 expression in Jurkat T cells cultured with FasL. FasL blocks expression of CD28 at the transcriptional level. This correlates with activation of caspase cascades: active caspase-3 can be detected and inhibitors of caspase-3 and caspase-8 increase CD28 promoter activity and CD28 expression. These findings are consistent with the hypothesis that apoptosis plays a key role in the age-related decline of CD28 expression and hence in immunosenescence.

[Oxidative stress profile: OSP].

Oxidative stress is known to be related to various diseases such as inflammation, carcinogenesis, arteriosclerosis and ischemia-reperfusion injury, and is also a major cause of aging. For the prevention of diseases and control of aging, evaluation and control of oxidative stress in vivo may become essential. We have developed the new Oxidative Stress Profile(OSP), a total diagnostic system which provides information about oxidative stress inside human body. The OSP system consists of a number of biomakers including oxidative damage markers, prooxidant factors, antioxidants and life style-related markers. The result is shown in a two dimensional plot form. We measured a combination of biomarkers for oxidative damage of biological components, serum antioxidants and analyzed oxidative stress. The result show that oxidative stress was elevated in diabetic patients in comparison with normal controls. Oxidative stress is also elevated in smokers in comparison with non-smokers. It is also interesting to find that oxidative stress can be greatly reduced by the improvement of life style such as diet. Oxidative Stress Profile system may become a powerful tool for the evaluation of oxidative stress in vivo, and may be useful in prevention of diseases, "mi-byo"(possible cause of diseases)-diagnosis and the control of aging.