Quantification Of Genomic DNA Damage In Lung and Nasal Epithelium and Response To Allergen Challenge
Saturday, March 3, 2018
South Hall A2 (Convention Center)
Adil S. Zahiruddin, MD, Koa Hosoki, MD PhD, Julia W. Tripple, MD, Pawel Jaruga, MsC, PhD, Dr hab, Erdem Coskun, Cynthia Rather, Robert L. Jacobs, MD, Miral Dizdaroglu, Sanjiv Sur, MD
RATIONALE: Repair of oxidatively-induced DNA base lesions can stimulate innate and allergic airway inflammation. Specific allergenic extracts like ragweed pollen extract and cat dander extract (CDE) induce TLR4-dependent oxidative stress and DNA damage. These studies suggest that stimulation of an innate receptor/adaptor by allergenic extracts initiates excision of a set of DNA-base lesions. The extent of DNA damage in the genome of nasal epithelial cells of human subjects has not been reported.

METHODS: Wild-type (WT) and Myd88KO naïve mice were intranasally challenged once with CDE, and oxidatively-induced DNA base lesions in lung genomic DNA was quantified by GC-MS/MS. Genomic DNA was isolated from Rhinoprobe nasal curettes samples collected from eight human subjects with asymptomatic allergic rhinitis (AAR) and four healthy human nonallergic control subjects (NC), and long-run real-time PCR technique for DNA-damage quantification (LORD-Q) assay was performed to quantify total damage to genomic DNA in these samples.

RESULTS: CDE challenge stimulated MyD88-dependent excision of DNA base lesions 5-OH-Cyt, FapyAde and FapyGua from the lung genome of mice and innate and allergic airway inflammation. The level of DNA damage in nasal epithelial cells was lower in AAR human subjects compared to NC human subjects.

CONCLUSIONS: These data suggest that repair and reduction of DNA base lesions in genomic DNA is associated with increased airway inflammation, whereas low levels of DNA damage is associated with an asymptomatic state in human subjects with allergic rhinitis.