During National Postdoc Appreciation Week, we are excited to shine a spotlight on the postdoctoral researchers at Amsterdam Cardiovascular Sciences. Postdocs are a vital part of our institute: they contribute to groundbreaking research, mentor young scientists, and bring new perspectives. In this series of short articles, we introduce some of our postdocs to you. We asked them about their research, their motivations, and their experiences as postdocs. Get to know the people behind the science and be inspired by their stories! Today in the spotlight: Josephine Tan, Postdoctoral researcher at Physiology (VUmc) and Cardiothoracic Surgery (AMC).

Josephine Tan
Josephine Tan

What is the most important or interesting topic you are currently working on, and why does it appeal to you?
I am a vascular biologist, currently working on Smooth Muscle Cells. These cells are essential for maintaining vessel integrity, yet they have this remarkable plasticity: they can completely change their identity, migrate out of the vessel wall, and adopt very different phenotypes that contribute to cardiovascular disease. They might take up lipids and become “foam cell”–like, secrete inflammatory cytokines, or turn into highly fibrotic, fibroblast-like cells. Strikingly, studies suggest that many of these diverse cell types can arise from a single smooth muscle cell that clonally expands within an aneurysm or atherosclerotic plaque. In fact, one clone can even give rise to the entire fibrous cap!

It is increasingly becoming clear that this process can greatly affect the progression and outcome of such cardiovascular diseases, yet how smooth muscle cells regulates their identity remains largely unclear.

When you stop and think about the transformations these cells undergo, it’s incredible, and it raises so many questions: how do these fate changes happen? Why does one cell switch while its neighbors don’t? Is there an intermediate cell state? How does the cell “know” which identity to become? Can they go back and forth between states? What signals guide these transitions? The fact that this cell type can have such a profound impact on disease progression, and that we understand so little about this, is what makes this work compelling to me.

What impact do you hope your research will have on the field of cardiovascular science or on society?
I really hope my research will contribute to understanding what these cellular “fate changes” do, and how they contribute to pathology directly (so not just an association). I also hope to unravel the regulatory networks that control these transitions. If we can find ways to influence smooth muscle cell behavior and direct them toward “healthier” fates, it could be transformative for a wide range of cardiovascular diseases: atherosclerosis, aneurysms, pulmonary hypertension, in-stent restenosis, and beyond. Even in the short term, better understanding of the molecular regulation can already help explain why patients with specific mutations experience such different outcomes. Ultimately, I would love to see this work contribute to identifying pharmacological targets, because right now, we don’t have therapies that specifically address smooth muscle cells.

What do you enjoy most or find most challenging about working as a postdoc, and do you have any tips for other early-career researchers?
Being a postdoc can be very stressful, difficult, and even lonely. Increased responsibility over your project and your career can be a double-edged sword: it’s all up to you now! The increased responsibility is exciting but also daunting: you’re designing, running, and analyzing your experiments, while also carving out your niche, applying for grants, networking, supervising, and writing. It can easily become overwhelming, and it’s very easy to “descend into madness”, especially when looking too far ahead.

So, take it step by step. I remind myself of this constantly. And -this may sound corny, but it works, try it!- take a moment to remember why you’re here. For me, I still get genuinely excited when I think about the biology itself, all the molecular processes happening simultaneously inside our cells every second: DNA replication, proteins being ubiquitinated, glycosylated, phosphorylated, cells migrating and dividing, receptors being internalized… When you pause to think about it, it’s staggering and just so cool! I just try to remember why I started this: I just love biology and want to understand more of it.

Postdoc appreciation week
From 15–19 September 2025, the Netherlands will host the first edition of Postdoc
Appreciation Week NL (PAW_NL). 

Events will be taking place accross the country. This is your opportunity to
connect, learn, and celebrate the contributions of postdoctoral researchers at
both local and national level

The program is published on the LinkedIn page Postdoc Appreciation Week NL and on the PostdocNL website Announcing Postdoc Appreciation Week – POSTDOCNL.

Photo: Adobe Stock