# Differential Expression of Antioxidant and Oxidant Pathways in Chronic Rhinosinusitis Without Nasal Polyps

## TL;DR

This study identifies unique redox gene expression patterns in chronic rhinosinusitis without nasal polyps, showing increased oxidative stress and distinct differences compared to cases with nasal polyps.

## Contribution

The study provides a systematic transcriptomic analysis of redox gene expression in CRSsNP, revealing unique antioxidant and oxidant pathway differences compared to CRSwNP.

## Key findings

- 27 redox genes were differentially expressed in CRSsNP, with 24 upregulated and 3 downregulated.
- CRSsNP showed a significant increase in oxidative stress compared to controls.
- CRSsNP and CRSwNP had 16 unique redox differentially expressed genes, indicating distinct pathophysiological mechanisms.

## Abstract

Chronic rhinosinusitis without nasal polyps (CRSsNP) is a chronic inflammatory disease that lacks a clear pathogenesis/pathophysiology. While large studies focused on elucidating the pathophysiology of CRS with NPs (CRSwNP), this study aimed to use a systemic evaluation approach to identify the redox gene expression profile, its association with oxidative damage in CRSsNP, and the differences between CRSsNP and -wNP. The expression of 84 redox genes was analyzed using real-time PCR array in control and CRSsNP nasal mucosae. Changes in the mRNA and protein levels of these redox differentially expressed genes (DEGs) were verified using a customized real-time PCR array, RT-PCR, and Western blotting in an additional 18 patients. 4-Hydroxynonenal (lipid peroxidation) and 3-nitrotyrosine (protein nitrosylation) expression, representing oxidative stress (OxS) and nitrosative stress (NsS) status, were examined using immunohistochemistry. We found 27 DEGs (24 upregulated and 3 downregulated) in CRSsNP. AKR1C2, GCLM, GPX2, NOS2, and NQO1 were upregulated and LPO was downregulated more than 4-fold. These changes led to a substantial increase in OxS in CRSsNP nasal mucosa. In a comparison of the currently identified 27 DEGs with the 23 previously reported CRSwNP genes, there were 16 unique redox DEGs expressed between CRSsNP and -wNP. A String protein interaction network analysis revealed that CRSsNP possessed “an adaptive antioxidant defense signature”, while CRSwNP showed “a pro-inflammatory and -oxidant pathway”. Collectively, we systemically performed transcriptomic analysis to profile OxS-related genes in CRSsNP and highlighted the unique redox gene sets and pathway differences between CRSsNP and -wNP.