Variation of long-chain 3-hydroxyacyl CoA dehydrogenase DNA methylated modification and correlation with gene mRNA expression of early-onset preeclampsia, HELLP syndrome and antiphospholipid syndrome in trophoblast cells of placenta

Abstract

By detecting the DNA methylation and gene expression of long-chain 3-hydroxyacyl CoA dehydrogenase(LCHAD)in trophoblast cells, analyze the correlation of DNA methylation and gene expression in early-onset preeclampsia(EPE), hemolysis, elevated liver enzymes, and low platelets(HELLP)syndrome and antiphospholipid syndrome(APS), to investigate the molecular basis of long-chain fatty acid oxidation changes in different preeclampsia and pathological pregnancy. Primary human cytotrophoblast cells and HTR8/Svneo cells were treated with serum from patients with EPE(14 cases), HELLP(12 cases), APS(14 cases), and normal pregnant women(NP, 14 cases). The methylation level of LCHAD gene promoter region through the MassARRAY platform and mRNA expression level by real-time fluorescent quantitative PCR technique were conducted. (1)Cytosine-phosphate-guanine(CpG)sites in human LCHAD DNA promoter region: CpG sites were detected in the range of 558 bp before LCHAD gene transcription start site, the detected CpG sites were 11 sites including 8 single sites and 3 complex sites. The position of these sites were at-984,-960,-899,-853,-811,-796,-774,-727,-615,-595,-579 respectively.(2)The sites of-899,-853,-615 and-595 showed increased methylation level in EPE and HELLP groups. The methylation level at-899,-853 and-615 sites in EPE and HELLP groups were significantly higher than those in NP group(P<0.01). The methylation level at-853 site was higher in EPE group than that in HELLP group(P<0.05). The-595 site showed the unmethylated in EPE, HELLP and APS groups. There were significantly difference between the 3 groups and EPE group(P<0.01).(3)The gene expression of LCHAD mRNA in EPE(0.048±0.005), HELLP(0.045±0.006)and APS(0.044±0.004)groups were significantly lower than NP group(0.076±0.009; P<0.01).(4)The correlation of methylation level and gene expression in all groups: the methylation level at-899,-853,-727,-615 and-579 sites were negatively correlated with gene mRNA expression in EPE group(P<0.05). The methylation level at-899,-853 and-615 sites were negatively correlated with gene mRNA expression in HELLP group(P< 0.05). The variation of LCHAD DNA methylation of trophoblast cells are found among EPE, HELLP syndrome and APS. The different correlation of LCHAD DNA methylation and gene expression are different in pathological groups. LCHAD DNA methylation of EPE and HELLP syndrome were significantly increased and negatively correlated with LCHAD gene mRNA expression. These results further revealed the molecular basis of long-chain fatty acid oxidation in different preeclampsia and pathological pregnancy.