Embryo development influenced by father's preconception environment

Paternal environmental factors, such as diet and gut microbiome, may impact early embryonic development in offspring.

Researchers at EMBL Rome, Italy, investigated how changes to the paternal microbiome and diet in mice can result in epigenetic changes in offspring. They found that these changes to paternal environment can affect early embryonic development by influencing pathways directly related to growth and development.

'Our study represents a step toward understanding the mechanism of epigenetic inheritance, particularly through the paternal line,' said Dr Jamie Hackett, corresponding author of the study, which was published in EMBO Journal.

'We have demonstrated that large-scale experiments are essential to untangle how specific environmental factors contribute to epigenetic inheritance across different genetic backgrounds,' said co-corresponding author Dr Ana Boskovic.

The researchers exposed male mice to one of two conditions before mating: either non-absorbable antibiotics, which induced dysbiosis of the gut microbiome, or a low-protein, high-sugar diet that mimics the typical Western diet. Using IVF, eggs were fertilised and embryos cultured for four days to the blastocyst stage, when differences in gene expression were measured between the embryos from the environmentally-disturbed mice and embryos fathered by control mice, who had been fed a standard diet.

Results showed that both types of environmental stress impacted gene expression. Specifically, gut microbiota disruption was found to be associated with reduced expression of extra-embryonic tissue development regulators, and impacted preimplantation growth occurred in the mice who had experienced dietary disruptions.

When the same experiment was repeated using a different strain of mice, the results differed, emphasising the importance of genetic background in how offspring are affected by environmental changes. Furthermore, parental age was shown to be another important factor, with embryos created from older male mice exhibiting stronger immune-related gene expression.

These findings provide insight into how pre-conception paternal environments could have implications for the health of future offspring. The authors hope to use their findings as a basis for further research that would use new analytical techniques to look for potential paternal environmental targets to mitigate risks of inherited diseases.