Foetal development (during pregnancy) is an incredibly complex process, influenced by both genetic and environmental factors that can have significant effects on the life of a baby after it is born. Facial development is especially important, not only for biological functions like eating or breathing, but also for social interactions, as the face is one of the main cues that people use to judge one another, consciously or otherwise. The processes underpinning early development are not fully understood, but a recent discovery by scientists in Sweden suggests that the food a mother consumes during pregnancy might be having a much more significant effect on the baby’s face than previously thought.
As with all human anatomy, development during gestation begins with stem cells. These are unspecialised cells which divide and acquire specific structures and functions, eventually becoming highly specialised “somatic” (adult) cells. In facial development, it is a cell type known as ‘neural crest cells’ that are ultimately responsible, interacting with many other cell types and altering how thousands of different genes are expressed. There is a complex interplay between active and inactive genes that results in changes in facial formation. The team, led by Dr. Meng Xie at the Karolinska Institutet, in Sweden, looked to see which genes were active during key periods of facial development. They determined that many of these genes were associated with the “mTORC1 pathway”, a key biological system that controls how proteins are made. This pathway is tightly regulated by the amount of amino acids (the building blocks of protein) that are circulating in the blood. When amino acids are scarce, the pathway is suppressed, meaning that protein synthesis slows down and fewer proteins are made. Therefore, if mothers eat less protein during key stages in pregnancy, then fewer amino acids will be available. This could lead to reduced activity of the genes needed for proper facial development.
To test their hypothesis, the team created genetically modified mice in which they could over-activate the mTORC1 pathway. This led to changes in how the mice’s faces developed, such as enlargement of several features, including the cartilage in the nose. In humans, this could impact breathing if facial development occurs in a similar way. However, when the experiment was repeated at a later stage in embryonic development, the changes to facial structure were much smaller. This suggests that there is a critical window of time during pregnancy, in which protein availability needs to be high in order to support correct facial development.
To confirm that protein intake was the cause of the changes in facial structure, the team studied two groups of pregnant mice. The first group was fed a normal, well-balanced diet, while the second group was given a low-protein diet. The embryos from the low-protein diet showed reduced mTORC1 activity and slightly underdeveloped facial structures. However, boosting the mTORC1 activity at just the right time restored normal development.
If the same process occurs in humans as it does in mice, this research could have far-reaching implications for how a mother’s diet affects their baby’s facial development. While ethical concerns prevent such an experiment from being conducted in humans, future retrospective studies may be able to identify the ideal pregnancy diet for a healthy baby.
Article written by Joshua Aderanti. Josh recently graduated from the University of Cambridge with a master’s degree in Biochemistry and currently works as an IT Consultant. He is passionate about all things biology, and is a tap and street dancer in his spare time.
Article edited by Eleanor Stamp, a Neuroscience PhD student at the Institute of Genetics and Cancer, University of Edinburgh, and an Online News Editor for EUSci.
Resources:
- Xie, M., Kaiser, M., Gershtein, Y. et al. The level of protein in the maternal murine diet modulates the facial appearance of the offspring via mTORC1 signaling. Nat Commun 15, 2367 (2024). https://doi.org/10.1038/s41467-024-46030-3
- Zeng, A. (2022). Daily organisation of cellular physiology by mTOR kinase [Apollo – University of Cambridge Repository]. https://doi.org/10.17863/CAM.95630
- Image details:
- Title: Craniofacial region of mouse embryo
- Description: Craniofacial region of a 13-day old mouse embryo by transmitted light microscopy. Categories: Research in NIH Labs and Clinics
- Photo Source: National Institute of Dental and Craniofacial Research (NIDCR)
- Creator: Craig Rhodes and Kenneth Yamada, LCDB, NIDCR
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