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Stem cell dynamics: the key to unveiling the mechanisms of skin aging and regeneration

Skin stem cells have the capability to produce mature cells in adult skin and are involved in wound healing, aging, and skin diseases. Here is more from the interview with Dr. Aiko Sada, Associate Professor at the International Research Center for Medical Sciences (IRCMS).

Exploring aging mechanisms using stem cells

Interviewer (◆ hereafter): Please tell us about your research!

Prof. Sada: Stem cells are the primary focus of my research. Stem cells have captured wide media attention because of the recent advancements in induced pluripotent stem (iPS) cell technology. Stem cells also reside in adult tissues, making copies of themselves while maintaining the ability to differentiate into mature cells in our body.
Because stem cells constantly produce new cells to replace old ones, the healthy human body can remain in good condition with the homeostatic mechanisms working wonderfully. My research interests relate to the mechanisms underlying tissue regeneration and stem cell regulation, similarities and differences of stem cells in different tissues, and many more.

◆: Are stem cells involved in the aging process?

Prof. Sada: Aging deteriorates stem cell functions. As a result, the skin becomes thinner, skin injuries require a longer time to heal, and people become more susceptible to cancer. Abnormalities and diseases in the elderly are associated with age-related stem cell dysfunction, or so-called “stem cell aging”. I am interested in elucidating how aging affects stem cell functionality.

◆: What triggered you to start researching stem cells?

Prof. Sada: My doctorate study focused on the germ cells. I was investigating the role of the RNA-binding protein Nanos2 in the development of germ cells. When I created a Nanos2-knockout mouse strain, I discovered that its stem cells were compromised. The Nanos2 gene is expressed in spermatogonial (sperm-producing) stem cells, suggesting its critical role in the maintenance of stem cells. This discovery fascinated me and turned my research focus to stem cells. I am now using skin stem cells as a model to further understand the mechanisms of tissue regeneration and aging.

The microscope image on the front page presents a topographical alignment of skin stem cells. “I am interested in the mechanisms for such a beautiful pattern formation of stem cells in skin,” says Prof. Sada.

Hoping to make new discoveries at Kumamoto University

◆: What excites you about your research activities?

Prof. Sada: If you pursue scientific research, you will encounter the moment when the unknown becomes known. Most experiments end up with negative results—at a rate of 95 out of 100. However, you may make new discovery once in three or ten years, if you persist. One day as you look into the microscope as usual, you may suddenly say to yourself, “Oh my, I may have found something terrific.” Those moments are the most thrilling part of my research activities.
Currently, I spend more time supervising the work of graduate students and postdocs. I am filled with joy when they come to me saying, “Look, Prof. Sada, I have some marvelous findings I want to show you.” Such experiences will make them more devoted to research, and I am honored to support their research and career.
I joined Kumamoto University as a faculty of the IRCMS in 2019. The IRCMS is a very attractive research institution, primarily focusing on stem cell research. Our research institute has first-class facilities and a characteristic “Open Lab” system, which aims to encourage communication and interaction across the laboratories. It helps early career scientists overcome common challenges, and supports their active research pursuits through the initiative and shared use of experimental equipment. The Kumamoto University also facilitates basic research. I believe that the passion of purely enjoying science and knowledge from basic research is the foundation of future innovation to make the world better place.
Discovering something new is my motivation. It is my desire to uncover the enigmatic nature of stem cells in skin aging and regeneration. The exciting part of basic research is that we are sailing an uncharted sea. We do not often know where our journey will lead us, but we press on simply because it is fun. I also enjoy collaborating and discussing with researchers in different disciplines.

Female researchers and family responsibilities

◆: Prof. Sada, you were awarded the FY2019 Kumamoto University Female Researcher Award.

Prof. Sada: Kumamoto University has been supporting female researchers.
Women in Japan often face many challenges that prevent us from pursuing research careers. Sometimes, it is the traditional way of thinking or gender stereotypes that get in our culture. I believe many parts of the social and institutional systems should evolve more rapidly.
In my family, my husband, who is a systems engineer, decided to shift from being a full-time employee to a freelance contractor so that I could continue my career.
The work–life balance of researchers needs more attention, discussion, and support. I hope that our society will become more diversified and various forms of family roles are chosen more freely.

Research competence goes a long way

◆: Please give a message to our students!

Prof. Sada: We welcome students with different backgrounds, expertise, interests, and future career plans. A team with different strengths, perspectives, and abilities will have a better chance of making innovations. I encourage my laboratory students to discuss freely with people and think about their immediate and ultimate goals.
Researchers need the ability to think through and execute their plans. We need to make, for example, 1-week, 3-month, and 1-year research plans, gather the necessary resources and information, communicate with people and manage teams. These abilities are also required for any types of work for creating new things and launching new projects. I hope students can learn research competence and skills here in Kumamoto University, and they will have a greater role to play across the world in the future.