Correlation of Bromodomain Protein BRD4 Expression With Epithelial–Mesenchymal Transition and Disease Severity in Chronic Rhinosinusitis With Nasal Polyps

Objectives: This study aimed to explore the relationship between bromodomain-containing protein 4 (BRD4), epithelial–mesenchymal transition (EMT), and disease severity in chronic rhinosinusitis with nasal polyps (CRSwNP). Methods: We performed immunofluorescent (IF) staining to evaluate the expression of BRD4 in the polyp tissues of CRSwNP and inferior turbinate mucosa of healthy controls. The relationship between BRD4 and EMT was evaluated by the BRD inhibitor JQ1 and BRD4 siRNA in primary human nasal polyp–derived epithelial cells. Disease severity was scored by using the Lund–Mackay scores of paranasal sinus computed tomography (CT) scans. Results: The expression of BRD4 in patients with CRSwNP was significantly higher than that in healthy controls. The loss of BRD4 function by the BRD inhibitor JQ1 and BRD4 siRNA resulted in the reduction of E-cadherin, increasing vimentin, and Snai1 mRNA expression. Moreover, the expression of BRD4 was related to the total CT scan scores (r = 0.4682, P = 0.0210). Conclusions: BRD4 had higher expression in CRSwNP than in healthy controls and might be associated with EMT in CRSwNP. BRD4 mRNA expression was associated with disease severity in CRSwNP.