Scientists Uncover New Details in How Sense of Smell Develops


Source: Washington University School of Medicine

Summary: Researchers have uncovered new details in how the olfactory epithelium develops. The new knowledge could help scientists prove that turbinates and the resulting larger surface area of the olfactory epithelium are one definitive reason dogs smell so well.


Dogs, known for their extraordinarily keen senses of smell, can be trained to use their sensitive sniffers to find drugs, bombs, bed bugs, missing hikers and even cancer. Among dogs and other animals that rely on smell, at least one factor that may give them an advantage is a sheet of tissue in the nasal cavity. In humans, this tissue called the olfactory epithelium, is a single flat sheet lining the roof of the nasal cavity. In dogs, however, the olfactory epithelium forms a complex maze, folding and curling over a number of bony protrusions, called turbinates, that form in the nasal cavity. Now, researchers at Washington University School of Medicine in St. Louis have uncovered new details in how the olfactory epithelium develops. The new knowledge could help scientists prove that turbinates and the resulting larger surface area of the olfactory epithelium are one definitive reason dogs smell so well. The study findings were published in the journal Developmental Cell.

Specialized epithelial tissue inside the nasal cavity

The olfactory epithelium — a mouse’s is pictured in green – is a sheet of tissue that develops in the nasal cavity. Researchers at Washington University School of Medicine in St. Louis have uncovered new details on how the olfactory epithelium develops and why it is that some animals have such great senses of smell, compared with others that lack such ability. Credit: Lu Yang

The team found that a newly discovered stem cell the researchers dubbed FEP cells control the size of the surface area of the olfactory epithelium. These stem cells also send a specific signaling molecule to the underlying turbinates, telling them to grow. The evidence suggests that this signaling crosstalk between the epithelium and the turbinates regulates the scale of the olfactory system that ends up developing, sometimes resulting in olfactory epithelia with larger surface areas, such as in dogs. When the stem cells can’t signal properly, turbinate growth and olfactory epithelium surface area experience an arrested development. To study this in the lab, mice with such olfactory stunting could, in theory, be compared with typical mice to learn more about how these signals govern the final complexity of an animal’s olfactory system.

First author Lu M. Yang said, “Before our study, we didn’t know how the epithelium expands from a tiny patch of cells to a large sheet that develops in conjunction with complex turbinates.”


More Information: Lu M. Yang et al, “FGF20-Expressing, Wnt-Responsive Olfactory Epithelial Progenitors Regulate Underlying Turbinate Growth to Optimize Surface Area”, Developmental Cell (2018). DOI: 10.1016/j.devcel.2018.07.010 


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