Association of DNA methylation and genetic variations of the APOE gene with the risk of diabetic dyslipidemia

Abstract

Apolipoprotein E (APOE) is a key regulator of lipoprotein metabolism, and consequently, affects the plasma and tissue lipid contents. The aim of the present study was to investigate the parallel effects of APOE genetic variants and promoter methylation levels of six CpGs on the risk of diabetic dyslipidemia. A total of 204 Palestinian type 2 diabetes (T2D) patients (mean age ± SD: 62.7±10.2) were enrolled in the present study (n=96 with dyslipidemia and n=108 without dyslipidemia). Next generation sequencing was performed to analyze five single nucleotide polymorphisms: Two variants rs7412 and rs429358 that determine APOE ε alleles, and three variants in the promoter region (rs769446, rs449647, and rs405509). For all subjects, the most common genotype was ε3/ε3 (79.4%). No statistical differences were observed in the APOE ε polymorphisms and the three promoter variants among T2D patients with and without dyslipidemia (P>0.05). A comparison of lipid parameters between ε3/ε3 subjects and ε4 carriers in both groups revealed no significant differences in the mean values of LDL-C, HDL-C, TG, and TC levels (P>0.05). Six CpG sites in the APOE promoter on chromosome 19:44905755-44906078 were identified, and differential DNA methylation in these CpGs were observed between the study groups. Logistic regression analysis revealed a significant association of DNA methylation level at the six CpGs with an increased risk of diabetic dyslipidemia (odds ratio, 1.038; 95% confidence interval, 1.012-1.064; P=0.004). In conclusion, the present study revealed that DNA methylation levels in six CpGs in the APOE promoter region was associated with the risk of diabetic dyslipidemia independently of the APOE ε4 variant which could be a potential therapeutic target to reverse the methylation of the APOE promoter.

Association of ApoE gene polymorphisms with serum lipid levels and the risk of type 2 diabetes mellitus in the Chinese Han population of central China

“…(2015) demonstrated that the ApoE CpG island’s DNA methylation landscape is altered by the presence of the ɛ 4 allele in brain tissue, and this epigenetic change increases the risk of Alzheimer’s disease. In a separate study, Ereqat et al. (2022) discovered that SNPs (rs769446, rs449647, and rs405509) in CpG sites in the ApoE promoter were associated with the level of DNA methylation in peripheral blood cells and that there was a difference in DNA methylation at these CpGs between patients with diabetic dyslipidemia and controls.…”

Association of c.+677 C>T (rs1801133) and c.+1298 A>C (rs1801131) MTHFR genetic variants with cardiometabolic and disease risk in systemic lupus erythematosus patients: A cross-sectional study

“…Regarding this, Leclerc et al reported that in murine models that c.+677 C>T variant was associated with MTHFR deficiency resulting in increased expression of pro-inflammatory HDL-C precursors and more significant lipid accumulation through alterations in the inflammatory response, lipid metabolism, and methylation capacity. 39 Until the exact mechanisms between MTHFR variants and lipid disturbances have not been fully understood, it could be related to altering methylation patterns in genes involved in lipid metabolism, 40 nevertheless, further research is necessary to understand the possible mechanisms involved in this alteration.…”