31 October 2022

Thesis defense Anna Klaus: “Cell-intrinsic and -extrinsic regulation of developmental hematopoiesis”

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Anna Klaus, from the group of Catherine Robin, has successfully defended her thesis “Cell-intrinsic and -extrinsic regulation of developmental hematopoiesis” on 31 October 2022. Klaus studied the network that controls the development of blood stem cells. These stem cells are responsible for the production of all types of blood cells and desperately needed in the clinic to treat blood-related diseases such as leukemia. Klaus’ thesis sheds light on how these precious blood stem cells arise in embryos.

Blood stem cells give rise to all types of blood cells and are therefore crucial for the formation of blood. These cells, also called hematopoietic stem cells (HSCs), are essential for the treatment of blood-related disease such as leukemia. Via blood cell transplantation, the cancerous blood cells in the bone marrow of the patient are replaced with healthy donor cells. However, there are risks associated with such a transplant: the donor HSCs can be rejected. To reduce this risk, researchers aim to develop techniques with which HSCs can be produced in the lab.

Blood stem cells in the lab

Before it is possible to produce blood stem cells in a petri dish, more knowledge is needed about the way this type of cell arises in live embryos. To that end, Klaus and her colleagues set out to investigate the network that controls the development of HSCs. They used state-of-the-art techniques to shed light on the role of various factors – both within the cells and in their direct environment – that regulate HSC generation. Although there is still a long way to go before HSCs can be successfully produced in a lab, the fundamental research that Klaus carried out during her PhD serves as a stepping stone towards this important goal.


Klaus says her PhD trajectory was a journey that taught her much about science, research and herself. “It is a beautiful experience to see how a project slowly unfolds and to eventually succeed in solving the mystery of the initial question,” she explains. She found a lot of joy and inspiration in the encounters, conversations and discussions she had with fellow scientists. “My PhD was not as straightforward as one might wish, but I am extremely grateful that I got to walk the entire way.” When asked about a specific highlight, Klaus mentions how special it felt when she finally pressed “send” for the submission of her thesis while watching the sun go down over the ocean.


Klaus calls doing a PhD an “extraordinary chance to learn about yourself”. “How do you cope? What motivates you? How patient, resilient, driven, ambitious, organized, courageous and stress-resistant are you?”. But she also believes that the trajectory is challenging for almost everybody. “It is a serious commitment, which you should not just embark on because it seems like the next logical step,” she says. “Nonetheless, anybody who loves science as much as I do and who is curious, creative and motivated, I would highly encourage to start the journey.”

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Anna Klaus pre-celebrated obtaining her doctorate by traveling and seeing a little bit more of the world. Now, she looks forward to finding a new task and challenge as a postdoc at Sanquin.