Young SWAN interview: Rubén Torregrosa Munumer

If you were explaining your research to someone with no scientific background, what story or image would you use?

We can compare pluripotent stem cells (cells that can become any cell type in our body) to a journey. At the beginning, they have many possible paths they can take, but as they start moving forward, they gradually commit to a path. Along the way, they constantly receive signals that guide their decisions, like road signs or checkpoints that help determine which direction to follow.

Inside each cell are tiny factories called mitochondria. They supply both the energy that powers the cell and the building blocks needed to make its components, among other things. All these chemical reactions together make up what we call metabolism. These small factories and the cell’s metabolism may act not only as the fuel that drives cellular function but also as a kind of compass: they do not just provide the energy to move forward, they may help determine which paths the cell can take, and which close off.

If mitochondria or metabolism do not function properly, they can alter the cell’s path. Sometimes the path may close off completely, or the cell may still reach its destination but not quite as it should. Small defects can also become evident only later. Therefore, these early stages are critical, since disease-related alterations may start upstream, even when clinical symptoms only appear much later in life.

What question is currently driving your research, and why does it matter to you?

We study how mitochondria act as signaling hubs beyond their traditional roles in energy production and biosynthesis during stem cell differentiation, particularly into neurons.

I find this particularly exciting because it represents an emerging area that could reveal new layers of regulation in complex cellular systems. Rather than acting as passive suppliers of energy, mitochondria may actively shape cellular trajectories through metabolic intermediates (e.g. “epimetabolites”), redox signalling, or interactions with other organelles, for instance. Understanding these mechanisms is important because subtle alterations may not cause immediate defects but can predispose cells to dysfunction later in life. This might be especially relevant in high-energy–demanding cells such as neurons, where early metabolic adaptations may contribute to vulnerability in late-onset diseases. By studying these connections, we hope to better understand how metabolic states influence cell fate and, ultimately, disease development.

How did you come to this research? What first made you curious?

I began exploring different research topics during my early bachelor’s studies in biology, when I knocked on the doors of several labs to do internships. Many topics attracted me, and it was clear that I wanted to work in the lab, but it was difficult to choose one. Everything seemed very interesting! These experiences exposed me to very different areas of biology, ranging from toxicity in plants and developmental biology to immunology and aging. The latter stood out: how do cells age? It focused on how an organelle I knew little about could contribute to aging, the mitochondrion. The more I read about it, the more intrigued I became. Despite their small size, mitochondria have a remarkable influence on cellular and whole-body physiology, not to mention their fascinating evolutionary origin. Are they simply passengers in the cell, or do they sit in the driver's seat? That question set the course for my scientific path.

After my Master’s, where I studied mitochondrial biology in aging, I moved abroad. Finland has a strong tradition in mitochondrial research, which led me to start my PhD at the University of Eastern Finland in the Pohjoismäki and Goffart lab, focusing on mitochondrial DNA maintenance.

I started my career focused on basic research, but gradually my interest shifted towards questions linked to human disease. This led me to join the Tyynismaa lab in medical neurogenetics at the University of Helsinki as a postdoc. There, I started working with human pluripotent stem cells and metabolism to model peripheral neuropathies. I found this field as interesting as my earlier work on mitochondria, and it also has strong potential for medical applications. This transition allowed me to connect the basic mitochondrial biology from my early career with the disease-relevant models I explored as a postdoc, shaping my current research on how metabolism and mitochondrial function influence cell fate decisions during neurogenesis.

What do you notice about the people drawn to your field — compared to those in other areas of science?

I think people in cell and molecular biology tend to be comfortable with complexity and uncertainty. Biological systems are largely messy and interconnected, so much of our work involves finding order in what first appears to be chaos. I believe this demands a combination of analytical thinking, intuition, persistence, and creativity since results not often follow a straight line. Compared to some other scientific fields that operate within clearer models or more predictable frameworks, biology constantly challenges its own assumptions. I think that attracts people who are both curious and especially adaptable, those who enjoy the puzzle of living systems and the process of turning uncertainty into understanding. But perhaps it is the same in every field: feeding our curiosity and finding clarity through complexity might be what science is all about.

Is there a question you have always wanted to ask another researcher in your area — but never quite had the chance?

I would ask another researcher what result or observation most changed the way they think about their research. In my experience, some of the most interesting insights come from data that do not fit our expectations, because they push us to question assumptions and rebuild our models. I would also be curious about negative results, those rarely shared yet important in shaping how we interpret data and plan experiments. These “hidden” findings could sometimes guide a field as much as the published ones, even if they remain out of sight. Such conversations do happen, but usually in informal moments rather than formal discussions. Scientific talks and papers emphasize polished results, while the reflections that truly change how we think tend to stay in the background.

What do you find exciting in science or has genuinely excited you in science recently — whether in your own work or in someone else's findings?

Often, what excites me most are not the big breakthroughs, but those moments when the data seem “wrong”. In science, we usually try to make sense of results through existing models, and most of the time that works well. But sometimes a small observation does not quite fit what we expect. At first, these results can feel confusing or even frustrating, and it is tempting to dismiss them as artefacts or simple variability. But when they keep appearing, they begin to point to something deeper.

I find those moments especially interesting because they often signal a shift in thinking. Not an immediate breakthrough, but a gradual recognition that the current model is not enough and that we need to approach the problem differently. For me, that is one of the most rewarding parts of science: when unexpected results make you slow down, question your assumptions, and see the system in a new way.

What do you personally do — or recommend others do — to age well and stay healthy?

I would probably recommend something I do not do enough: exercise. Caloric restriction is interesting because it is one of the few dietary interventions with evidence for influencing aging, but in humans the effects appear modest, and the long-term tradeoffs are still unclear. Nutritional supplements are another area that attracts a lot of attention, and some may help in specific situations, but the overall evidence is uneven, and many claims still need more studies. For example, resveratrol, a drug I tested in rats during my master´s, looks very promising in some animal models, but its benefits in humans are much less clear. People often look for a magic pill to solve everything, but some of the strongest evidence for healthy aging still comes from regular physical activity. And I believe taking care of mental health matters just as much. For example, by setting aside time for meditation or creative activities. For me, painting helps bring balance and clarity, and it is a way to manage stress during busy times.

What brings you satisfaction in research — the small, everyday kind?

Sometimes the most rewarding moments in research are quiet. It is that moment when an experiment finally works after weeks of frustration, when an annoying result suddenly makes sense, or when two ideas you had not connected before suddenly fit together. Those small flashes of clarity feel like breakthroughs. I also find great satisfaction in reproducibility, in knowing that something works not just once, but again and again. The first time a result holds up when you repeat it, or even better, when another lab confirms your findings, it feels different. It becomes something you can trust: your work and the idea itself. That is when you start to believe you are uncovering something real, not just chasing noise. In addition, part of this journey is also shared with others. Seeing how ideas evolve through discussion, how someone approaches a problem differently, or how a student grows more independent can be unexpectedly rewarding. It gives a sense that the work not only moves forward individually but also grows through shared effort.

But above all, what keeps me going is that rare feeling of being near the edge of what is known. Those moments when you realize that maybe, just maybe, you are seeing something no one has seen before. It is a quiet thrill, a mix of wonder and responsibility. And that feeling of discovery, of being part of something larger, makes every setback, every long day in the lab or the office, completely worth it.

Has there been a moment — in nature, in the laboratory, or simply in an unexpected place — that you found genuinely beautiful?

I think beauty often reveals itself in small things and quiet moments. Sometimes it happens in the lab, when an experiment finally works and the data begins to make sense. Other times, it appears outside science, a calm evening with family, a shared laugh, or simply the light filtering through the trees. In all these moments, everything seems to come together, clear and balanced, bringing a sense of peace.