Abnormal epigenetic regulation of the gene expression levels of Wnt2b and Wnt7b: Implications for neural tube defects

Abstract

The association between Wnt genes and neural tube defects (NTDs) is recognized, however, it remains to be fully elucidated. Our previous study demonstrated that epigenetic mechanisms are affected in human NTDs. Therefore, the present study aimed to evaluate whether Wnt2b and Wnt7b are susceptible to abnormal epigenetic modification in NTDs, using chromatin immunoprecipitation assays to evaluate histone enrichments and the MassARRAY platform to detect the methylation levels of target regions within Wnt genes. The results demonstrated that the transcriptional activities of Wnt2b and Wnt7b were abnormally upregulated in mouse fetuses with NTDs and, in the GC-rich promoters of these genes, histone 3 lysine 4 (H3K4) acetylation was enriched, whereas H3K27 trimethylation was reduced. Furthermore, several CpG sites in the altered histone modification of target regions were significantly hypomethylated. The present study also detected abnormal epigenetic modifications of these Wnt genes in human NTDs. In conclusion, the present study detected abnormal upregulation in the levels of Wnt2b and Wnt7b, and hypothesized that the alterations may be due to the ectopic opening of chromatin structure. These results improve understanding of the dysregulation of epigenetic modification of Wnt genes in NTDs.