Detection of global DNA methylation and paternally imprinted H19 gene methylation in preeclamptic placentas

Abstract

Preeclampsia (PE) is a severe hypertensive disorder associated with pregnancy; despite substantial research effort in the past several years, the etiology of PE is still unclear. The role of epigenetic factors in the etiology of PE, including DNA methylation, has been poorly characterized. In the present study, we investigated global DNA methylation as well as DNA methylation of the paternally imprinted H19 gene in preeclamptic placentas. Using 5-methylcytosine immunohistochemistry and Alu and LINE-1 repeat pyrosequencing, we found that the global DNA methylation level and the DNA (cytosine-5) methyltransferase 1 mRNA level were significantly higher in the early-onset preeclamptic placentas when compared with the normal controls. Data from methylation-sensitive high resolution melting demonstrated hypermethylation of the promoter region of the H19 gene, and results of real-time PCR showed decreased mRNA expression of H19 gene in the early-onset preeclamptic placentas as compared with the normal controls. Our results suggest that abnormal DNA methylation during placentation might be involved in the pathophysiology of PE, especially early-onset preeclampsia.

The imprinted H19 gene regulates human placental trophoblast cell proliferation via encoding miR-675 that targets Nodal Modulator 1 (NOMO1)

“…The JEG-3 cells were transfected with miR-675 mimics together with Nodalexpressing construct or pCDNA4 plasmid vector. Similar as our previous report, 23 we consistently observed Smad2 activation and growth inhibition in cells transfected with Nodal-expressing plasmid. As shown in Figure 3C and D, co-transfection of miR-675 mimics could substantially facilitate the Nodal effects on Smad2 phosphorylation and cell proliferation in JEG-3 cells.…”

“…21,22 We previously reported that PE placentas exhibited lower mRNA expression and hypermethylation in promoter region of H19 gene compared with normal placentas. 23 In the present study, we attempt to reveal the role of H19 gene in human . The levels of h19 and miR-675 were separately adjusted by that of GApDh and U6, and the relative value to corresponding Nc was presented as Mean ± seM according to three independent experiments.…”

Screening for differential methylation status in human placenta in preeclampsia using a CpG island plus promoter microarray

“…Kulkarni et al (31) measured the global DNA methylation level in placentas of women with PE using the Methylamp TM Global DNA methylation quantification kit. Using 5-methylcytosine immunohistochemistry and Alu and LINE-1 repeat pyrosequencing, Gao et al (32) investigated global DNA methylation as well as DNA methylation of the paternally imprinted H19 gene in preeclamptic placentas. There is relatively little concordance between our findings and these other reports.…”

Epigenetic mechanisms in physiologic and pathologic pregnancies

“…Az egyébként tumorszuppresszor hatású H19-gén fokozott expressziója humán embrionális szövetekben észlelhető; a szöveti növekedés és fejlődés regulációján túl -Yu és munkatársai vizsgálati eredményei alapján -részt vesznek a praeeclampsia patofi ziológiai folyamataiban [58]. Gao és munkatársai ugyanezen gén promoter régiójának fokozott metilációját tapasztalták praeeclampsiában, míg más vizsgálatok e terület hipometiláció-ját igazolták méhen belüli növekedési retardáció esetén [59,60]. E szempontból a CUL7-gén metilációs mintázatának alakulása praeeclampsia és IUGR esetén hasonló a H19 kapcsán tapasztalhatókhoz.…”