Crossing Borders in Epigenetics: A Pasteur-Oxford Approach to Infectious Disease Research

Interview with Leonardo Gonzalez-Smith

Tell us a bit about your experience before joining the Institut Pasteur and why you decided to come here for your next step?

LGS: Before joining the Institut Pasteur, I studied biology and biochemistry at Loyola Marymount University in Los Angeles, before spending three years working as a research technician at the University of Southern California during the COVID period. There, I focused on epigenetic research in cancer; looking at how genes can be switched on or off without changing the DNA itself, and how this affects disease.

That experience really shaped the way I think about science. I loved working on questions that had a clear relevance to human health and patient outcomes, and I wanted to continue in that space. At the same time, I was keen to broaden my scientific skill set by moving into infectious disease research, while still using the epigenetic tools I had developed.

The Institut Pasteur felt like the ideal place to do that. It’s a world-renowned institution whose name you encounter very early on in biology, from vaccines to pasteurisation.  The IP PhD programme would give me the opportunity to build on my research experience, even without a traditional Master’s degree, and to move into a new scientific field in an environment that values interdisciplinary and international research. It also offered something personal: the chance to step outside my comfort zone by living and working in a different country for the first time.

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What is the focus of your research at the Institut Pasteur?

LGS: My research sits at the intersection of epigenetics and infectious disease biology. In simple terms, epigenetics is about how cells control which genes are active or inactive. In cancer research, we know that disease can arise when genes are switched on or off at the wrong time. What we’re now learning is that infectious agents can exploit these same mechanisms.

At the Institut Pasteur, I study Streptococcus pneumoniae, a bacterium responsible for serious infections such as pneumonia and meningitis. My project looks at how an initial infection can cause lasting epigenetic changes in our own cells, effectively “reprogramming” how they respond to future infections.

The idea is that the bacteria may be hijacking the host’s genetic machinery to make reinfection easier later on. By understanding how these changes happen, we can gain new insight into why some infections recur and how the body’s immune response is altered over time. Ultimately, this kind of research could help inform new strategies for preventing or treating infectious diseases that remain a major global public health challenge.

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How does this translate to the collaboration with the University of Oxford? How will it benefit your research by spending time in the labs there?

LGS: The collaboration with Oxford is a wonderful opportunity for a possible future collaboration. At Pasteur, I’ve been able to use cutting-edge techniques to identify potential epigenetic targets that may be involved in how the infection reshapes the host response. What we now need to do is validate those findings and test them more deeply.

Oxford offers access to complementary expertise, technologies and assays that are ideally suited to this phase of the work, including specialised tools to target specific components of the epigenetic machinery. Working in Oxford labs could allow me to learn new techniques or set up a collaboration to confirm and strengthen our results, while also gaining new perspectives on how to approach the research question.

Importantly, the benefit goes both ways. The lab I work in at Pasteur is one of the few that truly bridges epigenetics and infectious disease biology, fields that are often studied separately. By moving between Pasteur and Oxford, I can help share methods, ideas and ways of thinking across institutions. That kind of researcher mobility accelerates discovery and strengthens both scientific communities.

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Outside of the scientific benefits, what do you think are the personal benefits to a programme like this?

LGS: Beyond the science, the personal and professional development that comes with a programme like this is invaluable. Working across institutions and countries forces you to become a better communicator, not just with other scientists, but with people outside the lab.

One of the most important skills I’m developing through this programme is the ability to clearly explain complex scientific ideas and why they matter for public health. Whether you’re collaborating internationally, speaking to funders, or engaging with the wider public, that skill is essential, and it’s something that doesn’t always get enough emphasis in scientific training.

On a personal level, moving from California to Paris has been transformative. It’s challenged me culturally, linguistically and socially, but it’s also been incredibly rewarding. Living and working in a different country has broadened my perspective, helped me build new networks, and reinforced the importance of international collaboration, especially at a time when global challenges like infectious disease demand shared solutions.

For me, the Pasteur–Oxford PhD programme isn’t just about one project or one lab. It’s about training scientists who can work across borders, disciplines and communities, and who are equipped to contribute to global public health in many different ways over the course of their careers.

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