Groundbreaking discovery: Bitter taste receptors identified in skin, functioning as a defense mechanism against harmful substances
image: Illustration of bitter taste receptor function in keratinocytes. On the left, harmful substances enter skin cells, leading to cellular damage. On the right, bitter taste receptors located in the endoplasmic reticulum detect these substances and activate efflux pumps to expel them, preventing cellular damage. The study suggests that receptor-activating compounds may enhance this detoxification process, offering potential applications for skin protection and anti-inflammatory treatments.
Credit: Okayama University of Science
First Study to Identify Their Role in Detecting and Expelling Harmful Substances
A research team from the Bioscience, and Cosmetic & Food Science courses in the Faculty of Life Science at Okayama University of Science has made a groundbreaking discovery: bitter taste receptors, previously believed to exist only on the tongue, are also present in keratinocytes (skin cells).These receptors play a crucial role in detecting and expelling harmful substances, making the first time such a function has been identified in the skin.
The Skin’s Role as Sensory and Protective Barrier
Bitterness serves as a biological warning system, alerting organisms to potentially harmful substances. On the tongue, bitter taste receptors in taste cells detect harmful substances in food, triggering an aversion response that prevents ingestion. However, harmful substances can enter the body not only through the mouth but also through the skin.
Unlike the tongue, the skin does not perceive bitterness as a taste. However, keratinocytes—the skin’s first line of defense—express bitter taste receptors that function as biological 'gatekeepers,' detecting harmful substances that penetrate the body and activating mechanisms to expel them, thereby contributing to skin protection.
Mechanism of Bitter Taste Receptors in Skin
The research team identified that bitter taste receptors are localized in the endoplasmic reticulum of keratinocytes. Upon detecting and binding to harmful substances, these receptors become activated and switch on efflux pumps, which expel them from the cell. This study is the first to demonstrate the protective biological role of bitter taste receptors in the skin.
Potential Applications: Skin Protection and Anti-Inflammatory Treatments
Some harmful substances cannot be detected by bitter taste receptors. In such cases, harmful substances accumulate within cells, potentially leading to skin damage and inflammation (see figure). However, this research suggests that artificially activating bitter taste receptors could trigger the body’s natural detoxification process, expelling accumulated harmful substances from cells.
This discovery opens new possibilities for developing safe receptor-activating agents, potentially leading to innovative skin protectants and anti-inflammatory treatments.
Published in a Leading Scientific Journal
This study was conducted in collaboration with the Graduate School of Pharmaceutical Sciences at Kyoto University and the Graduate Schools of Pharmaceutical Science, and of Medicine at the University of Tokyo. The findings were published online on August 27 in FASEB BioAdvances, a scientific journal issued by the Federation of American Societies for Experimental Biology (FASEB).