DNA methylation and expression of LGR6 gene in ankylosing spondylitis: A case-control study

Objective: The objectives of the present research were to ascertain the relationship of Leucine-Rich RepeatContaining G-Protein Coupled Receptors 6 (LGR6) methylation and transcript levels with ankylosing spondylitis (AS). Methods: Targeted bisulfite sequencing was applied to analyze LGR6 DNA methylation in 81 AS cases and 81 controls. Besides, the LGR6 transcription level of peripheral blood mononuclear cells (PBMCs) from 70 AS cases and 64 controls was measured utilizing quantitative real-time transcription-polymerase chain reaction (qRT-PCR). Results: The study detected the methylation levels of 43 sites in two CpG (cytosine-guanine dinucleotide) islands of LGR6 and found that LGR6 were significantly hypomethylated in AS patients (LGR6_1: P = 0.002; LGR6_2: P < 0.001). LGR6 transcript level was obviously reduced in AS (P = 0.001) and was positively related to DNA methylation level (CpG-1: P = 0.010; CpG-2: P = 0.007). Besides, the Receiver operating characteristic curve (ROC) exhibited good diagnostic performance of LGR6 methylation level (AUC = 0.676, 95% CI = 0.594-0.758, P < 0.001). Further subgroup analysis revealed that gender may affect the LGR6_1 methylation pattern. Conclusion: The present study revealed that LGR6 DNA methylation dysregulation may be involved in the pathogenesis of AS from an epigenetic perspective for the first time, with the aim of providing new directions for biomarker identification and treatment development for AS patients.