Maternal smoking during pregnancy leaves its lasting mark on the childs genetic make-up
If mothers smoke during pregnancy, they influence the epigenetic programming of their unborn child’s genetic make-up in the long term. This may give rise to an increased risk of the development of disease risks later in the child’s life. Researchers at the Helmholtz Centre for Environmental Research (UFZ) in Leipzig, the German Cancer Research Center (DKFZ) in Heidelberg and the Heidelberg University discovered that these changes are not limited to individual regions of DNA. In fact, the researchers stated in the Molecular Systems Biology journal that they particularly accumulate in enhancers of gene expression.
Maternal smoking during pregnancy is harmful to the unborn child as well as the mother. This is a known fact. “For the first time, we can now demonstrate that exposure to tobacco smoke also causes epigenetic changes in enhancers of gene expression,” said Irina Lehmann, Environmental Immunologist at the UFZ. These deregulated enhancers are distributed throughout the child’s entire genome.
Epigenetic changes form part of countless processes that occur during human development. The genetic material functions as a blueprint for all cells. In order for different cell types, e.g. liver or muscle cells, to develop, certain genes must be activated or deactivated at certain times. One of the ways this happens is through epigenetic changes which can be disrupted by various environmental factors. In their latest study, the group of researchers from Leipzig and Heidelberg revealed that epigenetic changes related to tobacco smoke increase the risk of children developing lung diseases.
The underlying data comes from the epidemiological study entitled LiNA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk). In this study, researchers asked which environmental factors could have a negative influence on children’s health during pregnancy. In collaboration with the Municipal Hospital “St. Georg” in Leipzig, UFZ researchers have been monitoring 622 mothers and their children since 2006. The mothers underwent in-depth examinations for possible exposure to environmental factors during their pregnancy.
For their current work, two groups of mother-child pairs were examined: mothers who smoked during pregnancy and mothers who were not exposed to tobacco smoke. Together with the genome researchers working with Roland Eils at the DKFZ and the Heidelberg University, the researchers examined the epigenome of the mothers and the children. They wanted to find out whether there was evidence of epigenetic changes in the smoker families that did not occur in the non-smoker families – and which consequences this may have for the children’s health. “We were able to find evidence of epigenetic changes in smoking mothers as well as in the umbilical cord blood of the newborn babies,” said Lehmann. The changes thus occur in the womb and affect the unborn child’s gene regulation.
The researchers determined that smoking particularly affects enhancer regions in the genome. Enhancers are DNA regions that regu