▲Professor Karl Deisseroth, a professor of bioengineering, psychiatry, and behavioral sciences at Stanford University in the United States

Professor Karl Deisseroth, recipient in the Basic Medicine category of the 18th Asan Award in Medicine, pioneered optogenetics, a genetic technique that uses light-responsive proteins to control cells in living tissues. He is currently considered a strong contender for the Nobel Prize in Physiology or Medicine. On March 17, the day before the award ceremony, he visited Asan Medical Center and the Asan Institute for Life Sciences, where he delivered a special lecture on optogenetics.

Q. Congratulations on receiving the Asan Award in Medicine.

A. I believe that for scientific research to truly succeed, creativity, principles, integrity, passion, and others must be sustained. I understand that the late Chairman Chung Ju-yung, founder of the Asan Foundation held similar beliefs about the noble spirit of the field of medicine. I feel deeply honored and delighted, as it seems that the efforts made over the years have been recognized.

Q. Where did the idea for optogenetics originate?

A. The inspiration came from opsins, light-sensitive proteins found in marine unicellular photosynthetic organisms such as green algae. However, expressing the genes that produce opsins in mammalian cells was extremely challenging, since the gene expression systems are different in algae and mammals. We kept an open mind and explored every possibility through continuous experimentation.

Q. How can optogenetics be applied to treat brain disorders?

A. In 2021, we published research demonstrating how optogenetics was used to treat a patient who had lost vision due to retinitis pigmentosa. It is possible to treat diseases by stimulating specific cells with light. Additionally, optogenetics can also help identify disease-relevant cells, which can indirectly influence new drug development. As research progresses on which cells to target and what to deliver for treating brain disorders, the application scope of optogenetics will broaden.

Q. Do you have any memorable anecdotes you would like to share?

A. After successfully conducting research at the cellular level in 2004, we were not sure for the first few years whether optogenetics could be applied to moving animals. There were also many concerns from those around me. One day in 2007, when a reporter from ‘The New York Times’ came to cover optogenetics, I felt the need to show something. We inserted an optical fiber into the motor cortex of a mouse’s right hemisphere and stimulated it with light. The mouse started spinning counterclockwise. When the light was turned off, the mouse stopped. That was the moment that I became convinced that optogenetics could be applied to moving animals.

Q. What is the direction for future developments?

A. With the development of opsins with higher sensitivity, it has become possible to control deep brain neurons just by shining light on the surface of the brain, eliminating the need for invasive optical fiber implants. Advancements will continue in this non-invasive direction. The range of applications must also expand. Our research team expressed opsins in the cardiomyocytes of mice and stimulated them using red LED vests. As a result, the cardiomyocytes were activated, and we were able to control the heartbeats at will. We plan to continue exploring applications in other organs as well.

Q. Lastly, is there anything you would like to say to readers?

A. To pioneer a new field, it is important to embrace the possibility of failure. Our own research faced extremely low odds, but we pursued it anyway. You should not dwell on the possibility of failure. It is also crucial to think differently from others. I believe there is even greater value in attempting what no one else has tried.