How a Chili Burn Led to a Nobel Prize

How a Chili Burn Led to a Nobel Prize

The 2021 Nobel Prize in Physiology and Medicine has been awarded to David Julius and Ardem Patapoutian for their discoveries of receptors for temperature and touch.

The two US-based scientists received the award for describing the mechanics of how humans perceive hot and cold, and pressure from nerve impulses.

Julius is a professor at the University of California, San Francisco. Patapoutian is a professor at the Howard Hughes Medical Institute at Scripps Research in La Jolla, California.

“Our ability to feel heat, cold and touch is essential for survival and supports our interaction with the world around us,” the Nobel Assembly said in a statement announcing the award.

“Julius used capsaicin, a pungent compound from chili peppers that induces a burning sensation, to identify a sensor in the nerve endings of the skin that responds to heat… Patapoutian used pressure-sensitive cells to discover a new class of sensors that respond to mechanical stimuli in the skin and internal organs,” it added.

Thomas Perlmann, the secretary of the Nobel Assembly and Nobel Committee, said the discovery “unlocks nature’s secrets … It explains at the molecular level how these stimuli are converted into nerve signals. It is an important and profound discovery.”

A Nobel medal displayed at a ceremony in New York. (AP)

The Nobel Committee explained that when Julius began investigating why capsaicin causes a burning sensation, the compound was already known to activate nerve cells that cause pain — but exactly how that happens was an “unsolved mystery.”

Julius and his team created a library of millions of DNA fragments that correspond to genes expressed in the sensory neurons that can respond to pain, heat and touch. They then put genes from this collection into cells that normally don’t respond to capsaicin to find the single gene that caused the sensitivity.

Julius later realized that the capsaicin receptor he discovered is a heat-sensitive receptor that is activated at temperatures perceived as painful, according to the Nobel Committee.

At the same time, Patapoutian and his collaborators tried to understand how mechanical stimuli could be transformed into our senses of touch and pressure.

How a Chili Burn Led to a Nobel Prize
David Julius poses at the 8th Annual Breakthrough Awards Ceremony at the NASA Ames Research Center in 2019. (Peter Barreras / Invision / AP)
Thomas Perlmann, Secretary of the Nobel Council and Nobel Committee, announces the winners of the 2021 Nobel Prize in Physiology or Medicine. (AP)

They identified a cell line that responded when the individual cells were pricked with a micropipette. The team then identified 72 candidate genes that could encode receptors and “switched them off one by one” to discover the one responsible for mechanosensitivity.

Abdel El Manira, a deputy member of the Nobel Committee on Physiology and Medicine, said the discovery was made more than a decade ago.

“It’s the right time (for it) to be recognized. It has profoundly changed our view of how we feel the world… Over the past year, we’ve missed our sense of touch – for example, during a hug. These are the receptors that give us the feeling of warmth and closeness,” he said.

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