David Julius and Ardem Patapoutian, two researchers from the United States, have won the Nobel Prize for Physiology or Medicine for their discoveries on the receptors that allow humans to feel temperature and touch. The findings could unlock new ways of treating pain for a wide range of disease conditions. 

Julius used capsaicin, a compound from chili peppers, to identify a sensor in the nerve endings of the skin that responds to heat, while Patapoutian used pressure-intensive cells to uncover a new class of sensors that respond to mechanical stimuli in the skin and in the organs. This improved our understanding of the link between our senses and the environment. 

“The groundbreaking discoveries by this year’s Nobel Prize laureates have allowed us to understand how heat, cold and mechanical force can initiate the nerve impulses that allow us to perceive and adapt to the world,” the Nobel committee said in a statement. “In our daily lives, we take these sensations for granted.”

Cheers and congratulations to our newest medicine laureate David Julius!

Here Julius and his wife Holly Ingraham are celebrating his #NobelPrize with a cup of early morning coffee.

Photo: Holly Ingraham. pic.twitter.com/e3QhlUqaqv

— The Nobel Prize (@NobelPrize) October 4, 2021

How do we perceive the world?

Over the years, researchers have studied the mechanisms underlying our senses, such as how sound waves affect our inner ears and how light is detected by the eyes. In 1944, for example, Joseph Erlanger and Herbert Gasser won the Nobel Prize for discovering different types of sensory nerve fibers that react to different stimuli. 

Since then, researchers have demonstrated that nerve cells are highly specialized to detect and transduce different types of stimuli, allowing a nuanced perception of our surroundings. But there was still an unsolved question. How are temperature and mechanical stimuli transformed into electrical impulses in the nervous system?

Julius worked with the chemical compound capsaicin, which was already known to activate nerve cells causing pain sensations, but researchers weren’t exactly sure how. He and his team created a library of DNA fragments of the genes expressed in sensory neurons and with time identified a single gene that made cells capsaicin-sensitive. 

As the mechanisms for temperature sensation became clearer, there were still open questions regarding how the mechanical stimuli were converted into our senses of touch and pressure. This is where Patapoutian enters the stage. He and his team identified a cell line that produced a measurable electrical signal when individual cells were nudged with a pipette. 

They assumed that the receptor activated by mechanical force was an ion channel, identifying 72 candidate genes encoding possible receptors. They inactivated each gene, one by one, to discover the one responsible for mechanosensitivity in the studied cells. They finally identified the single gene whose silencing made the cells insensitive to poking with the pipette.

“Intensive ongoing research originating from this year’s Nobel Prize awarded discoveries focusses on elucidating their functions in a variety of physiological processes. This knowledge is being used to develop treatments for a wide range of disease conditions, including chronic pain,” the Nobel committee said. 

Founded by Swedish inventor Alfred Nobel, the Nobel Prizes have been awarded since 1901. The Nobel Prize of Physiology or Medicine is often overshadowed by the Nobel’s for literature and peace but medicine has been in the spotlight this year amid the pandemic, with the Covid-19 vaccine creators also seen as top contenders this year.

Patapoutian was born in 1967 in Lebanon and then moved to Los Angeles in his youth. He’s now a professor at Scripps Research in La Jolla, California, having previously worked at the University of California in San Francisco. Julius, 65, is a professor at the University of California after previously working at Columbia University in New York.

Both received the award at their own homes, from where they followed the online ceremony with their family, as shared in Twitter. The usual banquet in Stockholm was postponed for a second year in a row due to concerns about Covid-19 and international travel. The two researchers will also get gold medal and $1.14 million in cash.