Cold-inducible RNA-binding protein contributes to tissue remodeling in chronic rhinosinusitis with nasal polyps

Cold-inducible RNA-binding protein (CIRP) is a newly identified damage-associated molecular pattern molecule. Its roles beyond promoting inflammation and in human diseases are poorly understood. This study aimed to investigate the involvement of CIRP in chronic rhinosinusitis with nasal polyps (CRSwNP).

Immunohistochemistry, quantitative RT-PCR, and ELISA were used to detect the expression of CIRP and matrix metalloproteinases (MMPs) in sinonasal mucosal samples and nasal secretions. Human nasal epithelial cells (HNECs) and THP-1 cells, a human monocytic/macrophage cell line, were cultured to explore the regulation of CIRP expression and MMP expression.

Cytoplasmic CIRP expression in nasal epithelial cells and CD68⁺ macrophages in sinonasal tissues, and CIRP levels in nasal secretions were significantly increased in both patients with eosinophilic and noneosinophilic CRSwNP as compared to those in control subjects. IL-4, IL-13, IL-10, IL-17A, TNF-α, Dermatophagoides pteronyssinus group 1, and lipopolysaccharide induced the production and secretion of CIRP from HNECs and macrophages differentiated from THP-1 cells. CIRP promoted MMP2, MMP7, MMP9, MMP12, and vascular endothelial growth factor A (VEGF-A) production from HNECs, macrophages differentiated from THP-1 cells, and polyp tissues, which was inhibited by the blocking antibody for Toll-like receptor 4, but not advanced glycation end products. The expression of MMPs and VEGF-A in tissues correlated with CIRP levels in nasal secretions in patients with CRSwNP.

The upregulated production and release of CIRP from nasal epithelial cells and macrophages may contribute to the edema formation in both eosinophilic and noneosinophilic CRSwNP by inducing MMP and VEGF-A production from epithelial cells and macrophages.