Hypomethylation of IL8 promoter in nasal epithelial cells of patients with chronic rhinosinusitis with nasal polyps

Abstract Background IL-8 is an important chemokine implicated in the pathogenesis of chronic rhinosinusitis (CRS), but little is known about epigenetic regulation of IL8 in the pathogenesis of CRS. Objective To investigate the relationship between the DNA methylation level in IL8 proximal promoter and CRS in Han Chinese. Methods CRS patients with (CRSwNP; n=187) and without nasal polyps (CRSsNP; n=89), and control subjects (n=57) were enrolled in two independent cohorts. Purified nasal epithelial cells (HNECs) from each participant were assessed for percentage % DNA methylation of CpG sites in IL8 proximal promoter using bisulfite pyrosequencing; and for functional aspects of methylation status using in-vitro assays. Results DNA methylation of CpG sites 1, 2, and 3, respectively, in IL8 proximal promoter was significantly decreased in HNEC of CRSwNP patients compared with CRSsNP patients ( P P P P P P IL8 expression, accompanied by reduction in methylation at the CpG3 site ( P Conclusion Decreased DNA methylation of particularly CpG sites in IL8 proximal promoter may play a role in pathogenesis of CRSwNP.