FIGURE 2.
OGG1-initiated DNA base excision repair results in the recruitment of neutrophils. (A) Kinetics of neutrophil recruitment to the airways after OGG1-BER (empty columns) or challenge with 8-oxoG base (filled columns, 0.0005 mg/kg). Each time point represents the average number of neutrophils from 5 to 6 mice. (B) Representative images of differentially stained cells derived from the BALF of saline- (left panel), OGG1-BER (middle panel) and 8-oxoG (right panel)-challenged airways. (C) Immunohistochemical identification of neutrophils based on neutrophil elastase localized to cell membrane (Materials and Methods). Magnification x144. (D) OGG1 deficiency in airway epithelia decreases the accumulation of neutrophils. (E) The 8-oxoG base challenge-induced recruitment of neutrophils is OGG1-dependent. (F) 8-oxoG base induces dose-dependent increases in the recruitment of neutrophils to airways. (G) OGG1-independent changes in neutrophil numbers upon uric acid (0.0005 mg/kg) challenge. (H) 8-oxoG, but not 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG), 8-oxoguanine deoxynucleoside (8-oxodG) or guanine induces neutrophil recruitment. In A,D,F,G and H, BALF was obtained at 16 h post-challenge, total cell numbers were determined, and cyto-spin preparations made for differential staining with Wright-Giemsa to determine neutrophil counts. 8-oxoG, FapyG, 8-oxodG, guanine base or uric acid was introduced via the intranasal route in 60 μL saline. 8-oxoG, 7,8-dihydro-8-oxoguanine; OGG1-BER, OGG1-initiated DNA base excision repair; Uric A, uric acid; ** = P<0.01; *** = P<0.001; **** = P<0.0001.