The Role of EZH2 in Initiating Epigenetic Regulation of CRSwNP.

Purpose: Chronic rhinosinusitis with nasal polyps (CRSwNP) was a polygenic disease whose pathogenesis involved epigenetic mechanisms. This study aimed to analyze biomarkers and pathways associated with CRSwNP using RNA-sequencing and explore the role of key biomarkers in the inflammatory response through epigenetic regulation in nasal mucosal cells. Particularly on EZH2, a key epigenetic regulator and histone methyltransferase, to explore its potential for CRSwNP immunotherapy.

Patients and methods: A total of 86 individuals were included between July 2021 and July 2023, including 43 patients with CRSwNP who underwent nasal polyp surgery and 43 patients with a deviated septum. Initially, differentially expressed genes (DEGs) between CRSwNP and control groups were screened using the obtained transcriptomic sequencing CRSwNP dataset. Biomarkers were filtered using machine learning algorithms and validated using immunohistochemistry (IHC) and quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The expression of enhancer of zeste homolog 2 (EZH2) was knocked down via siRNA and overexpressed through plasmid transfection in human nasal epithelial cells (HNEpCs). The effects of EZH2 overexpression and knockdown on the expression of high-mobility gene group A2 (HMGA2) activation and H3k27me3 expression were assessed using qRT-PCR and immunofluorescence.

Results: EZH2, insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), and HMGA2 were revealed as potential biomarkers which screened from five target genes. Gene set enrichment analysis and immune infiltration analysis revealed the most critical gene was EZH2, with its expression exhibiting a positive relationship with HMGA2. Moreover, EZH2 knockdown upregulated H3k27me3 expression and inhibited HMGA2 activation. In contrast, EZH2 overexpression downregulated H3k27me3 expression and promoted HMGA2 activation. Notably, the expression levels of IGF2BP1, EZH2, and HMGA2 were higher in the CRSwNP group than in the control group.

Conclusion: This study identified three potential biomarkers, IGF2BP1, EZH2, and HMGA2, associated with CRSwNP. Notably, EZH2 could serve as a new adjuvant immunotherapy target in CRSwNP through the modulation of epigenetic mechanisms.