Dataset Information

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children.

ABSTRACT:

Background

Inducible nitric oxide synthase (iNOS; encoded by nitric oxide synthase isoform 2 [NOS2]) is the major enzyme for nitric oxide synthesis in airways. As such, measurement of fractional concentration of exhaled nitric oxide (Feno) provides an in vivo assessment of iNOS activity. Short-term exposure to air pollution, haplotypes, and DNA methylation in the NOS2 promoter has been associated independently with iNOS expression, Feno levels, or both.

Objective

We aimed to examine the effects of ambient air pollutants, NOS2 promoter haplotypes, and NOS2 promoter methylation on Feno levels in children.

Methods

We selected 940 participants in the Children's Health Study who provided buccal samples and had undergone Feno measurement on the same day. DNA methylation was measured with a bisulfite-PCR Pyrosequencing assay. Seven single nucleotide polymorphisms captured the haplotype diversity in the NOS2 promoter. Average particulate matter with an aerodynamic diameter of 2.5 ?m or less (PM(2.5)) and 10 ?m (PM(10)) or less and ozone and nitrogen dioxide levels 7 days before Feno measurement were estimated based on air pollution data obtained at central monitoring sites.

Results

We found interrelated effects of PM(2.5), NOS2 promoter haplotypes, and iNOS methylation on Feno levels. Increased 7-day average PM(2.5) exposure was associated with lower iNOS methylation (P = .01). NOS2 promoter haplotypes were globally associated with NOS2 promoter methylation (P = 6.2 × 10(-8)). There was interaction among 1 common promoter haplotype, iNOS methylation level, and PM(2.5) exposure on Feno levels (P(interaction) = .00007).

Conclusion

Promoter variants in NOS2 and short-term PM(2.5) exposure affect iNOS methylation. This is one of the first studies showing contributions of genetic and epigenetic variations in air pollution-mediated phenotype expression.

SUBMITTER: Salam MT

PROVIDER: S-EPMC3487398 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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Publications

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children.

Salam Muhammad T MT Byun Hyang-Min HM Lurmann Fred F Breton Carrie V CV Wang Xinhui X Eckel Sandrah P SP Gilliland Frank D FD

The Journal of allergy and clinical immunology 20111104 1

<h4>Background</h4>Inducible nitric oxide synthase (iNOS; encoded by nitric oxide synthase isoform 2 [NOS2]) is the major enzyme for nitric oxide synthesis in airways. As such, measurement of fractional concentration of exhaled nitric oxide (Feno) provides an in vivo assessment of iNOS activity. Short-term exposure to air pollution, haplotypes, and DNA methylation in the NOS2 promoter has been associated independently with iNOS expression, Feno levels, or both.<h4>Objective</h4>We aimed to exami ...[more]

PMID: 22055874

Similar Datasets

Project description:BACKGROUND:Exhaled nitric oxide (FeNO), a biomarker of airway inflammation, predicts asthma risk in children. We previously found that the promoter haplotypes in inducible nitric oxide synthase (NOS2) and exposure to residential traffic independently influence FeNO level. Because NOS2 is inducible by environmental exposures such as traffic-related exposure, we tested the hypothesis that common NOS2 promoter haplotypes modulate the relationship between residential traffic-related exposure and FeNO level in children. METHODS:In a cross-sectional population-based study, subjects (N = 2,457; 7-11 year-old) were Hispanic and non-Hispanic white children who participated in the Southern California Children's Health Study and had FeNO measurements. For residential traffic, lengths of local roads within circular buffers (50m, 100m and 200m radii around homes) around the subjects' homes were estimated using geographic information system (GIS) methods. We interrogated the two most common NOS2 promoter haplotypes that were found to affect FeNO level. RESULTS:The relationship between local road lengths within 100m and 200m circular buffers and FeNO level varied significantly by one of the NOS2 promoter haplotypes (P-values for interaction between road length and NOS2 promoter haplotype = 0.02 and 0.03, respectively). In children who had ?250m of local road lengths within 100m buffer around their homes, those with two copies of the haplotype had significantly lower FeNO (adjusted geometric mean = 11.74ppb; 95% confidence intervals (CI): 9.99 to 13.80) than those with no copies (adjusted geometric mean = 15.28ppb; 95% CI: 14.04 to 16.63) with statistically significant trend of lower FeNO level with increasing number of haplotype copy (P-value for trend = 0.002). In contrast, among children who had >250m of local road lengths within 100m buffer, FeNO level did not significantly differ by the haplotype copy-number (P-value for trend = 0.34). Similar interactive effects of this haplotype and local road lengths within 200m buffer on FeNO were also observed. CONCLUSIONS:Higher exposure from residential traffic nullifies the protective effect of one common NOS2 promoter haplotype on FeNO level. Regulation of traffic-related pollution may protect children's respiratory health.

Dataset Information

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children.

Background

Objective

Methods

Results

Conclusion

Publications

Genetic and epigenetic variations in inducible nitric oxide synthase promoter, particulate pollution, and exhaled nitric oxide levels in children.

Similar Datasets

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