Nuclear factor‐κB activity is down‐regulated in nasal polyps from aspirin‐sensitive asthmatics

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Abstract
Background: We examined whether a decreased activity of nuclear factor(NF)-κB), a transcriptional regulator of cyclooxygenase-2 (COX-2), could account for down-regulation of COX-2 in nasal polyps of aspirin-sensitive asthmatics. Methods: Nasal polyps were obtained from 17 aspirin-intolerant asthma/rhinitis patients (AIAR; 7 men, mean age 48 ± 12 years) and 23 aspirin-tolerant asthma/rhinitis patients (ATAR; 12 men, mean age 65 ± 11 years). COX-2 mRNA expression was measured using semiquantitative reverse transcriptase competitive polymerase chain reaction (RT-PCR), and the results were expressed as mean ± standard error of 106 molecules of mRNA/µg of total RNA. NF-κB binding was measured with 32P-labeled oligonucleotides and electrophoretic mobility shift assay (EMSA), and the results were expressed as a percentage with respect to the mean EMSA obtained in 19 healthy nasal mucosa. Results: The mean levels of COX-2 mRNA expression (0.25 ± 0.06) and NF-κB activity (89 ± 13) in nasal polyps from AIAR were significantly lower than in polyps from ATAR (COX-2 = 1.58 ± 0.50, and NF-κB = 143 ± 12, P < 0.01 and P < 0.05, respectively). Levels of COX-2 mRNA and NF-κB activity in polyps from patients on corticosteroid therapy did not differ statistically from those who were not on this therapy before polypectomy. Conclusion: This study shows that the low expression of COX-2 mRNA in nasal polyps from aspirin-sensitive patients is associated with a down-regulation of NF-κB activity.