Epithelial genes in chronic rhinosinusitis with and without nasal polyps

Abstract

Background: Genetic studies on chronic inflammatory diseases have resulted in an emphasis on the epithelial interface with the environment and the genes that influence this interaction. This study examines the expression of key epithelial genes implicated in the pathogenesis of other inflammatory disorders for their role in chronic rhinosinusitis (CRS).

Methods: Epithelial cells were collected from the inferior turbinate, middle turbinate, and/or uncinate from 62 subjects undergoing sinonasal surgery. Patient groups included 21 CRS patients with nasal polyposis, 23 CRS patients without nasal polyposis, and 18 controls. Samples were analyzed for S100A7, S100A8, S100A9, SLC9A3R1, G-protein-coupled receptor for asthma, and serine protease inhibitor kazal type 5 (SPINK5) by quantitative real-time polymerase chain reaction. Immunohistochemistry (IHC) was performed to analyze expression of SPINK5 lympho epithelial kazal-type inhibitor (LEKTI) in sinonasal samples.

Results: Expression of S100A7 and S100A8 was significantly decreased in CRS with and without nasal polyps when compared with controls. S100A9 expression was significantly decreased in CRS without nasal polyps, and SPINK5 expression was significantly decreased in CRS with nasal polyps. SPINK5 (LEKTI) protein was detected in sinonasal tissue and was significantly decreased in polyp samples using IHC.

Conclusion: This study shows marked reductions in the level of expression of several genes involved in epithelial barrier maintenance and repair in the inflammatory state of CRS.

Figure 1

Average Ct of mRNA of the target genes is shown. The Ct is the cycle at which a noticeable increase in fluorescence above the baseline signal is detected. A lower Ct represents a higher level of mRNA present in the sample. A higher bar, therefore, correlates to a higher level of genetic expression.

Figure 2

Real-time PCR levels of expression of target genes in sinonasal tissue normalized to the housekeeping gene HPRT. The significant values are starred and error bars represent SEM.

Figure 3

Immunohistochemical staining for LEKTI in epithelial cells from the uncinate process and polyp tissue at 400× magnification. (A) Control IgG of uncinate from CRSwNP subject does not stain for LEKTI. (B) LEKTI staining of uncinate from a control subject shows intense staining in the epithelial and glandular tissue, whereas light to moderate staining of LEKTI is seen in uncinate samples from (C) CRSsNP and (D) CRSwNP. (E) Minimal LEKTI staining in epithelial and glandular cells is seen in polyp tissue. Glandular staining reveals similar trends. (F) Glandular staining in the uncinate of a control subject with intense staining for LEKTI. Less staining is again seen in the uncinate from (G) CRSsNP and (H) CRSwNP.