The whole blood DNA methylation of RAB8A and RAP1A in autoimmune thyroiditis: evidence and validation of iodine exposure in a population from different water iodine areas

ABSTRACT

Our study aimed to identify and verify G protein-related methylated genes in AIT patients, while also investigate those genes in AIT patients exposed to iodine in different water iodine areas. Different areas were classified by median water iodine (MWI) concentrations: Iodine-Fortified Areas (IFA, MWI<10µg/L), Iodine-Adequate Areas (IAA, 40≤MWI≤100 µg/L), and Iodine-Excessive Areas (IEA, MWI>100 µg/L). We studied 176 AIT cases and 176 controls, with 89, 40, and 47 pairs in IFA, IAA, and IEA, respectively. Using the Illumina Human Methylation 850k BeadChip, we identified candidate methylated genes. MethylTarget^TM and QRT-PCR validated DNA methylation and mRNA expression. Results showed hypomethylation and high expression of RAB8A and RAP1A in all 176 AIT cases. RAB8A's CpG sites were mainly hypomethylated in IFA and IEA, while RAP1A's sites were primarily hypomethylated in IEA. This study underscores how water iodine exposure may influence RAB8A and RAP1A methylation in AIT.

KEYWORDS:

• Iodine
• water
• autoimmune thyroiditis
• DNA methylation

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/09603123.2023.2280148.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant no.82073490).