DNA Methylation of KLRC1 and KLRC3 in Autoimmune Thyroiditis: Perspective of Different Water Iodine Exposure

Abstract

Objective: This study aimed to identify differentially methylated genes (DMGs) associated with natural killer cells in patients with autoimmune thyroiditis (AIT), focusing on the influence of varying water iodine exposure levels.

Methods: Participants were divided into categories based on median water iodine (MWI) concentrations: iodine-fortified areas (IFA, MWI < 10 µg/L), iodine-adequate areas (IAA, 40 ≤ MWI ≤ 100 µg/L), and iodine-excessive areas (IEA, MWI > 300 µg/L). A total of 176 matched AIT cases and controls were recruited and divided into 89, 40, and 47 pairs for IFA, IAA, and IEA, respectively. DMGs were identified using 850K BeadChip analysis for 10/10 paired samples. Validation of DNA methylation and mRNA expression levels of the DMGs was conducted using MethylTarget™ and QRT-PCR for 176/176 paired samples.

Results: KLRC1, KLRC3, and SH2D1B were identified as significant DMGs. Validation revealed that KLRC1 was hypomethylated and highly expressed, whereas KLRC3 was hypermethylated and highly expressed in individuals with AIT. Furthermore, KLRC1 was hypomethylated and highly expressed in both IFA and IEA.

Conclusion: The DNA methylation status of KLRC1 and KLRC3 may play crucial roles in AIT pathogenesis. Additionally, DNA methylation of KLRC1seems to be influenced by different iodine concentrations in water.

Keywords: Autoimmune thyroiditis; DNA methylation; Iodine; KLRC1; KLRC3; SH2D1B.