Japanese scientist Yoshinori Osumi wins Nobel Prize in medicine

NOBEL PRIZE WINNER — File photo taken in March 2015 shows Japanese scientist Yoshinori Osumi attending a press conference in Tokyo after winning the Canada Gairdner International Award. Osumi won the 2016 Nobel Prize in physiology or medicine on Oct. 3 for discovering and elucidating mechanisms for autophagy, an intracellular process that degrades and recycles proteins. Kyodo News photo

STOCKHOLM — Japanese scientist Yoshinori Osumi won this year’s Nobel Prize in physiology or medicine for discovering and elucidating mechanisms for autophagy, an intracellular process that degrades and recycles proteins, the Nobel Assembly at the Karolinska Institute said Oct. 3.

The 71-year-old professor emeritus at the Tokyo Institute of Technology revealed the mechanism of how autophagy begins, opening up the possibility of new treatments for illnesses including cancer, and Alzheimer’s and Parkinson’s diseases.

Osumi’s discoveries “led to a new paradigm in our understanding of how the cell recycles its content. His discoveries opened the path to understanding the fundamental importance of autophagy in many physiological processes, such as in the adaptation to starvation or response to infection,” the assembly said in a statement.

“I’m truly honored,” Osumi told Kyodo News by telephone upon being named the 25th Japanese to win a Nobel Prize and fourth to win the prize in physiology or medicine. The Fukuoka native follows Satoshi Omura, a Japanese scientist who won the same prize last year.

Autophagy, Greek for “self-eating,” plays a housekeeping role by degrading abnormal or unnecessary proteins in cells. It is also a conserved self-digestive process, in which cells adapt to starvation by decomposing their own proteins and using them as new energy sources.

In 1988, Osumi, for the first time in the world, observed the process with an electron microscope by using a yeast cell and discovered how a cell degrades its own constituents and reuses them as energy in a vacuole.

The process had been roughly known since the 1950s but it was never observed before Osumi.

Since its self-cleaning function is believed to be a key for maintaining bodies’ health, recent studies have found that an abnormality in the autophagy process is connected to cancer and Alzheimer’s and Parkinson’s diseases.

Osumi conducted an experiment with mice and found that when the self-digestive process does not function in liver cells, the cells bloated and became cancerous. When he tested the same thing in the brain, old and abnormal proteins aggregated in nerve cells, leading to Alzheimer’s and other neurodegenerative diseases.

Born as the youngest of four brothers in Fukuoka city in southwestern Japan, Osumi entered the University of Tokyo and finished a doctoral program before studying at the Rockefeller University, where he was intrigued by budding yeast cells, which later led to his breakthrough in the understanding of autophagy.

Osumi then returned to Japan and as an assistant researcher at the University of Tokyo began studying budding yeast cells, before his successful observation of the autophagy process in 1988.

Osumi’s findings also advanced research on the genes responsible for autophagy and his team contributed to the identification of most of the 18 specific genes essential to autophagy in yeast.

Last year, Omura shared the Nobel Prize in physiology or medicine with two scientists from Ireland and China for their discoveries concerning therapies against parasitic diseases, after fellow Japanese Shinya Yamanaka won the same prize in 2012.