Evaluation of IRF7 mRNA and its Association with Promoter Methylation in Kashmiri (North-Indian) Patients with Systemic Sclerosis: A Case-Control Study.

Introduction: The interferon regulatory factor 7 (IRF7), a member of the IRF family of transcription factors, plays a major role in the regulation of numerous aspects of an immune response and has increasingly been surveyed to determine the aetiology and pathogenesis of systemic sclerosis (SSc). Objective: This study aimed to investigate the transcriptional levels of IRF7 mRNA in peripheral blood mononuclear cells (PBMCs) and the impact of promoter methylation on IRF7 mRNA expression in SSc patients compared to healthy controls.

Methods: PBMCs were obtained from confirmed 40 naïve SSc cases and 20 healthy controls for IRF-7 expression and methylation analysis. mRNA expression was performed using the quantitative real-time polymerase chain reaction (SYBR green method) concerning the housekeeping gene. A promoter methylation profile study was carried out by bisulfite treatment of DNA, followed by methylation-specific polymerase chain reaction (MS-PCR) in SSc cases against controls.

Results: The relative expression analysis revealed that the selected IRF7 gene was upregulated in the patient group compared to healthy controls (p=0.003). In addition, mRNA expression of IRF7 was significantly increased in the limited cutaneous group compared to the diffuse cutaneous group. Moreover, SSc cases had hypomethylated IRF7 promoters compared to controls, and the significant impact of IRF7 promoter methylation on mRNA expression was observed (p=0.001).

Conclusion: IRF7 overexpression in PBMCs from SSc patients may be caused by IRF7 promoter demethylation, and this aberrant expression of IRF7 in SSc might provide a link between the prominent IFN signature and the development of SSc.