High sFlt‐1 Concentrations During Pregnancy Modulate the Ppara Promoter Methylation in the Fetal Liver

Abstract

BackgroundAn adverse prenatal environment significantly increases the risk of chronic metabolic diseases in the offspring. The mechanisms underlying such programming are unclear but may involve epigenetic modifications that lead to altered fetal gene expression. It was demonstrated that poor maternal nutrition affects the DNA methylation status of important transcriptional factors in the liver. However, little attention has been given to other pathological events during pregnancy e.g. increased concentrations of soluble fms‐like tyrosine kinase‐1 (sFlt‐1). Our working hypothesis is that increased sFlt‐1 concentrations in the mother can influence the developmental plasticity and the phenotype of the offspring via resetting of DNA methylation marks.MethodsPregnant Sprague‐Dawley rats were injected with control or adenovirus overexpressing sFlt‐1 on gestational day (GD 8). Fetal plasma, body and organ weight were assessed on GD 19. Microarray analysis was performed to assess the offspring liver gene expressions. The candidate gene methylation status was verified by pyrosequencing.ResultsPlasma concentrations of sFlt‐1 peaked 48 h post injections in the treated animals, and the high concentrations were maintained until the end of the pregnancy. The fetal sFLt‐1 concentrations were increased and body weight and length were decreased in the sFlt‐1 group. There were no significant differences in the brain weight between the groups, but the livers were smaller in comparison to the respective control group. Microarray analysis revealed 623 differentially expressed genes in the fetal liver. The functional analysis indicated a significant effect on lipid metabolism and in particular fatty acid beta‐oxidation. Moreover, Ppara, a transcriptional factor and key regulator of hepatic lipid metabolism, was one of the most induced genes by the high sFlt‐1 concentrations present in the mother and in the offspring. In addition, we performed pyrosequencing, to confirm whether Ppara overexpression is accompanied by changes in the methylation of the respective promoter. The promoter region of Ppara revealed decreased methylation in the high sFlt‐1 group in comparison to the controls, which is in accordance to the observed gene overexpression.ConclusionOur data show that increased sFlt‐1 concentrations in the mother and the offspring lead to growth restriction, brain sparing and Ppara upregulation in the liver. This is accompanied by Ppara promoter hypomethylation. Overall this suggests that epigenetic mechanism may induce the altered phenotype of the offspring via high sFlt‐1 maternal concentrations.Support or Funding InformationThis work was supported by the Netherlands Organization for Health Research and Development (ZonMW, grant number 91211053).