Transgenerational Inheritance of Betaine-Induced Epigenetic Alterations in Estrogen-Responsive IGF-2/IGFBP2 Genes in Rat Hippocampus.
SCOPE
Betaine serves as a methyl donor for DNA methylation. Here, the effects of betaine on hippocampal expression of neurogenesis genes and their DNA methylation status across three generations are investigated.


METHODS AND RESULTS
Pregnant rats (F0) are fed control and betaine-supplemented diets throughout gestation and lactation. Female F1 and F2 offspring at weaning, together with the F0 dams, are used in the study. Hippocampal expression of aromatase, estrogen receptor α, and estrogen-related receptor β is downregulated in F1, together with the estrogen-responsive insulin-like growth factor 2/insulin-like growth factor binding protein 2 (IGF-2/IGFBP2) genes. However, all these genes are upregulated in F2, which follows the same pattern of F0. In agreement with changes in mRNA expression, the imprinting control region (ICR) of IGF-2 gene is hypomethylated in F1 but hypermethylated in F2 and F0. In contrast, the promoter DNA methylation status of all the affected genes is hypermethylated in F1 but hypomethylated in F2 and F0. Methyl transfer enzymes, such as betaine homocysteine methyltransferase and DNA methyltransferase 1, follow the same pattern of transgenerational inheritance.


CONCLUSION
These results indicate that betaine exerts a transgenerational effect on hippocampal expression of estrogen-responsive genes in rat offspring, which is associated with corresponding alterations in DNA methylation on ICR of IGF-2 gene and the promoter of affected genes.
['Yang|Yang|Y|', 'Jiang|Wenduo|W|', 'Yang|Shu|S|', 'Qi|Fulei|F|', 'Zhao|Ruqian|R|0000-0002-7337-8173']
D000818:Animals D001141:Aromatase D001622:Betaine D001835:Body Weight D019175:DNA Methylation D019587:Dietary Supplements D044127:Epigenesis, Genetic D004967:Estrogens D005260:Female D018392:Genomic Imprinting D006624:Hippocampus D018971:Insulin-Like Growth Factor Binding Protein 2 D007335:Insulin-Like Growth Factor II D007774:Lactation D008297:Male D011247:Pregnancy D011297:Prenatal Exposure Delayed Effects D011401:Promoter Regions, Genetic D017207:Rats, Sprague-Dawley
transgenerational inheritance IGF-2/IGFBP2 hippocampus betaine estrogen receptors