Smelling with skin

We smell with our nose, or do we? Recently scientists have found that for some smells we can smell with our skin, and those smells can heal wounds. Our ability to smell requires olfactory receptors which are often found in the nose. Humans have about 400 of these receptors, 350 of which are in the nose, while others have been shown to exist in sperm, the prostate, intestines, and kidneys. Recently Daniela Busse and colleagues discovered yet another place that olfactory receptors reside¹, your skin!

Skin is the largest organ in the human body as it protects our insides from our outsides. This recent report shows that our skin can also sense our environment. Busse and colleagues went on to show that the particular olfactory receptor is very good for detecint sandalwood oderants. Sandalwood oderants which are often found in perfumes and cleaning agents but originally come from the East Asian sandalwood tree (a rare tree and therefore an expensive substance).

The group also showed that incubating cells with the sandalore chemical increased proliferation of the cells by about 30%. Even more interesting, they showed that the sandalore smell increased wound healing - wounds were healed to 50% of initial wound in about half the time!

Everyone should care, at least, to know that their skin may be more sensitive than we realize - as these authors show that the skin can “smell” a specific chemical. Biological engineers also care a lot, because this opens up new avenues for wound healing lotions by targeting the olfactory receptors in the skin to promote healing.

Humans have hundreds of oderant receptors, but only about 40 have published ligands associated with them². Scientists are now trying to catalog the ligands that associate with each receptor, as well as discover where all the remaining receptors are expressesd!

References

1. Busse, Daniela, et al. “A synthetic sandalwood odorant induces wound-healing processes in human keratinocytes via the olfactory receptor OR2AT4.” Journal of Investigative Dermatology 134.11 (2014): 2823-2832.
2. Mainland, Joel D., et al. “Human olfactory receptor responses to odorants.” Scientific data 2 (2015).