Maternal smoking during pregnancy leaves its lasting mark on the child's genetic make-up

http://www.eurekalert.org/pub_releases/2016-04/hcfe-msd040516.php

Public Release: 5-Apr-2016
Maternal smoking during pregnancy leaves its lasting mark on the child's genetic make-up
First study to show changes in epigenetic enhancer regions and their relation to the child's diseases later in life
Helmholtz Centre for Environmental Research - UFZ

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.

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The researchers also determined that the epigenetic effects observed in the umbilical cord blood at birth can still be seen several years after the child is born. However, it could not be ascertained beyond doubt whether these effects are long-term impacts of exposure to smoke prior to birth. "Children who are exposed to tobacco smoke even before being born usually continue to be exposed to this after their birth," said Lehmann. She added that the prolonged exposure to cigarette smoke after birth may contribute to the observed stability of epigenetic changes.

In their analysis, the researchers identified more than 400 enhancers affected by tobacco smoke. They regulate genes that play a role in a variety of diseases such as diabetes, adiposity or even cancer. "This discovery will allow us to start understanding the mechanisms that make smoking the cause of such a wide range of diseases," said Roland Eils.

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