Developing a toolbox to study the rabbit methylome and its alteration in IUGR cases during gestation

Abstract

Epigenome is the essential mediator of the effect of environmental exposures on development. Epigenetic studies show that alterations in DNA methylation marks are associated with developmental reprogramming and linked to environmental exposures. Our objective is to develop different Intra Uterine Growth Restriction (IUGR) rabbit models and to study the alterations occurring in the methylome of the placental unit throughout gestation. The relevance of the rabbit model resides in its placentation similarity with humans. As little is known about rabbit epigenome, we are developing a strategy to establish a toolbox to study the rabbit methylome. First, studying the methylome of the placental unit will be performed by MeDIP-seq on pooled samples to generate a methylation overview in both placenta (fetal compartment) and decidua (maternal compartment) at term. In a second time, a microarray will be designed for individual analysis to establish early epigenetic events related to placenta from IUGR. The array design will integrate methylated sequences from MeDIP-seq data but also promoters of differentially expressed genes obtained by transcriptomic analysis performed on the same samples. Finally, to validate our results, methylated regions of interest will be studied by pyrosequencing after bisulfite treatment. The identification of critical epigenetic marks alterations associated with IUGR will allow a better understanding of the IUGR process and an identification of key actors in placental function. In future studies, these marks could be linked to the establishment of a specific phenotype at adulthood and tested as biomarkers at birth to define the risk of developing an adverse phenotype. In addition, this study will present the first overview of the rabbit methylome and lead to the development of epigenomic tools that can be used systematically