The second event of the “Pioneers Host Pioneers” (PHP) series, hosted by STELLAR SCIENCE FOUNDATION (SS-F), took place on July 29, 2024, at FabCafe Tokyo in Shibuya. The event was held in a hybrid format, combining an in-person gathering with online streaming. PHP is designed to provide participants with fresh perspectives for their daily research activities through guest lectures and dialog sessions. What makes this event unique is that not only the guest speakers but also the moderators are active researchers at the forefront of their fields.
This time, the moderator was Associate Professor Kohki Okabe from the Graduate School of Pharmaceutical Sciences at the University of Tokyo, and the guest speaker was Shingo Kajimura, a leading expert in adipocyte research and a professor at Harvard Medical School. Dr. Kajimura has been advancing research on brown adipose tissue, which plays a crucial role in energy regulation in organisms, with the goal of translating these findings into new treatments for metabolic disorders.
On the day of the event, Tokyo experienced a scorching heat with temperatures exceeding 35 degrees Celsius (95 degrees Fahrenheit). At the beginning of his lecture, Dr. Kajimura lightened the mood by joking, “Perhaps it was a mistake to talk about heat on such a hot day in Tokyo.” His talk, titled “How Do Cells Make Heat?”, began with a discussion on the importance of body temperature.
Fat Cells Essential for Biological Evolution
In the context of evolution, the ability to generate body heat was a significant milestone for living organisms. Maintaining body heat allowed organisms to move at night, venture north into colder climates, and survive the winter. Brown adipose tissue plays a critical role in this heat production. Unlike white adipose tissue, which stores energy, brown adipose tissue contains many mitochondria, the organelles responsible for energy production.
These cells are abundant in infants, who cannot generate heat through muscle shivering, but recent research over the past decade has shown that adults also possess brown adipose tissue, and its proportion is related to metabolic health. In addition, brown adipose tissue (beige fat cells) induced from white adipose tissue by prolonged exposure to cold has also been discovered.
A New Approach to “Mimicking” Cold
Although brown adipose tissue is activated in cold environments, it is not easy to translate this knowledge directly into treatment. “Cold is uncomfortable for humans and puts a strain on the heart, so I thought about whether we could ‘mimic’ cold,” Dr. Kajimura explained. He mentioned that in studies with mice, they successfully raised body temperature using optogenetics by exposing cells to pulsed light.
“There are many organisms other than mammals, such as snakes, hummingbirds, and even plants, that can generate heat. However, we don’t fully understand all the mechanisms,” Dr. Kajimura said. He is currently studying tuna, which have a mechanism to warm their eyes and brains in cold ocean water without the presence of sarcomeres (the smallest units of muscle contraction).
This suggests that there is a mechanism for generating heat other than muscle shivering. Dr. Kajimura concluded his talk by sharing his vision to continue research on cellular heat generation using the diversity of organisms as a tool.
Similarities Between Fishing and Science
After the seminar, the second part of the event, the “Fireside Chat,” began. This session allowed participants to engage in relaxed dialogue, as if gathered around a fireplace or campfire. Sean McKelvey, SS-F’s Strategic Designer, facilitated the discussion, drawing out various insights from both the host, Dr. Okabe, and the guest, Dr. Kajimura.
The first topic was curiosity. Dr. Kajimura shared that he has been curious about many things since childhood, especially his enduring fascination with fish. “Fishing is a lot like science. It’s important to imagine what you want to catch and keep trying, and patience is key. I enjoy the process of deciding where to buy lunch, where to go and what to fish for,” he said.
Of course, enjoying the process means that sometimes you will experience failure. But Dr. Kajimura spoke cheerfully about this, saying, “There are things to be learned from failure, so you have to enjoy it. Whether in fishing or science, if you want to catch something big, you should go where no one else has gone. Sometimes you won’t catch anything, but that’s life. Dr. Okabe agreed, saying, “I prefer to avoid competition whenever possible. I believe that by exploring areas where no one else is, I can truly become a pioneer.
Dr. Kajimura noted that when something truly captivates you, you naturally keep going, no matter the challenges. It’s not about forcing yourself or relying on sheer willpower; it’s about pursuing it until you’re satisfied. However, many adults may feel that they’ve lost the curiosity or passion they had as children. When Sean asked a simple question, Dr. Kajimura replied, “I don’t think you have to stick to one subject. I’m indifferent to most things, but I can remain passionate about certain things. I see this as both my strength and my weakness.
Impact on Society and the Role of Researchers
The research on body temperature and fat cells, the topic of this event, also has significant social implications. When asked if making socially impactful discoveries takes time away from research, Dr. Kajimura replied, “Biotechnology is very exciting. There may be more I could do in the industry. But the key point is that I always ask myself if it’s something I really need to do. If someone else can do it better than I can, I’ll delegate it to them and offer my support as needed.
Regarding the growing investment in biotech start-ups, Sean asked if this trend is affecting research topics. Dr. Kajimura replied, ” Financial incentives are important, but not the most essential. Synergy is what really matters. For example, achieving ‘cold mimicking’ at a higher level might be better handled by industry. The key is to think about what synergies can be created through programs.
Research Lab as a “Farm”? Perspectives on Recruitment
The second half of the second part focused on recruitment and mentoring. When asked how he handles recruitment and mentoring, Dr. Kajimura said, “I do not try to influence others’ thinking through mentoring. The important thing is to help them become independent thinkers.
Dr. Kajimura emphasized the importance of diversity among scientists and researchers, noting that people have different mindsets and backgrounds. “Outsiders, those from different fields or unconventional backgrounds, are the ones who make breakthroughs. I aspire to be like that, and when hiring, I want to bring in people who have different perspectives“ Reflecting on this, Dr. Okabe said, “A research lab is like a farm. You build a boundary around it, and within that fence, everyone is free to do what they want. But I don’t know what the best size for a farm is,” he laughed.
Finally, when discussing attitudes toward research, Dr. Kajimura said, “When you make a new discovery, there are times when you may face criticism. It can be frustrating, but that frustration is also an opportunity. History shows that new technology combined with careful observation leads to breakthroughs. Dr. Kajimura often reminds his students that “observation” is key. “Irreproducible results are where discoveries begin. If your results are different from last week, it can be frustrating, but it can also lead to surprises and new insights. I encourage my students to openly share their failures and irreproducible results in meetings.
Even as the seminar drew to a close, the lively discussions among participants continued, reflecting the lasting impact of the day’s insights.
<Interview and Writing by Takayuki Honda>
