Nuclear Factor κB/MicroRNA-155 Upregulates the Expression Pattern of Cytokines in Regulating the Relapse of Chronic Sinusitis with Nasal Polyps and the Underlying Mechanism of Glucocorticoid

BACKGROUND The aim of this study was to explore the upregulated nuclear factor kappaB (NF-kappaB)/microRNA-155 (miR-155) in regulating inflammatory responses and relapse of chronic rhinosinusitis (CRS) with nasal polyps (NP), which underlies the molecular mechanism of glucocorticoid treatment. MATERIAL AND METHODS The study recruited 25 patients with eosinophilic (Eos) CRSwNP, 25 patients with Non-Eos CRSwNP, 25 patients with CRS without NP (CRSsNP) and 30 patients with nasal septum deviation (control group). The expression of NF-kappaB/miR-155 and inflammatory cytokines was detected in epithelial tissue specimens. Additionally, a mouse model of Eos CRSwNP was established, and the mice were treated by NF-kappaB inhibitor, miR-155 antagomir, or dexamethasone (DEX) to explore the role of NF-kB/miR-155 and the anti-inflammatory effects of glucocorticoid treatment. RESULTS Results showed that the expression level of NF-kappaB/miR-155 was significantly elevated in the Eos CRSwNP group, accompanied by the upregulation of cytokines: tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-4, IL-5 (P<0.05) compared with the control group, the CRSsNP group or the Non-Eos CRSwNP group. The upregulation of NF-kappaB/miR-155 increased inflammatory mediator cyclooxygenase2 (COX2) while decreasing anti-inflammatory mediator Src homology-2 domain-containing inositol 5-phosphatase 1 (SOCS1), which resulted in the aberrant expression pattern of cytokines in the mice model. DEX treatment inhibited the expression of cytokines and decreased the relapse rate of Eos CRSwNP via inhibiting NF-kappaB/miR-155 (P<0.05). CONCLUSIONS The upregulation of NF-kappaB/miR-155 was crucial in mediating the aberrant expression of inflammatory cytokines in Eos CRSwNP. This molecular mechanism is a concern with the high relapse rate of Eos CRSwNP. However, glucocorticoid treatment inhibited the relapse of CRSwNP via downregulation of NF-kappaB/miR-155.