Investigation of CpG Island Methylation in the Promoter Region of the FOXP3 Gene in Biopsy Samples from Patients with Inflammatory Bowel Disease (IBD)

Authors
davood Jafari
Kimia Yousefiyeh
Golshid Sanati
Nasser Ebrahimi
Nima Rezaei
Abstract
Introduction: Recently, the role of epigenetic alterations in the FOXP3 gene as an essential regulatory transcription factor in the function of regulatory T cells (Tregs), including immune tolerance maintenance and response regulation in Inflammatory Bowel Disease (IBD), has gained significant attention. This study aimed to investigate the CpG island methylation status in the promoter region of the FOXP3 gene in the pathogenesis and prognosis of patients with IBD.

Methods: Colorectal biopsy samples were obtained from 42 patients with active IBD (22 with ulcerative colitis (UC) and 20 with Crohn’s disease (CD)) and 20 healthy controls. Genomic DNA was bisulfite-treated using the MethylEdge™ Methylation Kit according to the manufacturer’s protocol. FOXP3 gene methylation status was assessed using quantitative real-time methylation-specific PCR (QM-MSP).

Results: Quantitative methylation assessment data revealed that the FOXP3 promoter methylation in the IBD patient groups, including CD patients (mean unmethylated DNA 0.476±0.218) and UC patients (mean unmethylated DNA 0.715±0.487), was significantly higher compared to the control group (mean 1.304±1.152) (P < 0.0001). No significant difference was found in the methylation status of CpG sites in the FOXP3 promoter between CD and UC patients (P > 0.05).

Conclusion: Abnormal methylation in the FOXP3 gene, a critical immune regulator, can lead to impaired Treg function and consequently increase the risk of inflammatory bowel diseases.
Keywords
FOXP3
DNA Methylation
CpG Islands
Inflammatory Bowel Diseases
Epigenetics
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