Prof. dr. M.H.M. (Marca) Wauben

Prof. dr. M.H.M. (Marca) Wauben

Professor Intercellular Communication

Utrecht University, Faculty of Veterinary Medicine

Department of Biomolecular Health Sciences

Marca Wauben

Biography:

Marca Wauben is Full Professor in intercellular communication and an expert in deciphering the role of nano-sized cell-derived vesicles (EVs) in intercellular communication in biological systems with emphasis on the immune system. Nowadays, EVs are being recognized as important messengers comprised of selected proteins, (small)RNAs and lipids involved in the modulation of specific target cells. Besides investigating fundamental immunological and regenerative aspects of EV-mediated communication the ‘Wauben EV group’ works on EV-based biomarker discovery, (therapeutic) EV applications and the development of (nano)technology to analyze EVs, e.g. high resolution flow cytometry-based technology enabling single EV-based analysis and sorting. She is author of over n=150 peer reviewed scientific publications and (Co-)recipient of multiple EV-based research grants, e.g. FP7 EU COST Action Microvesicles and Exosomes in Health and Disease (2012; vice-chair), H2020-MSCA-ITN-2016 TRAIN-EV research & training Network (722148) (2017) and H2020-FETOPEN The EV Foundry (801367)(2018). She has been/and is involved in many national and global initiatives to build a scientific community centered around EV-biology; e.g. the founding of the International Society for Extracellular Vesicles (ISEV) in 2011 (currently Secretary General) and scientific journal “Journal of Extracellular Vesicles” (PubMed) (associate editor) and the founding of the Netherlands Society for Extracellular Vesicles (NLSEV) in 2018 (founding President). In 2018 she delivered the Tom Watson oration 2018, University of Sydney, Faculty of Pharmacy (Sydney, Australia) ‘Extracellular vesicles: From biology to biomedical application’ and she received the ISEV Special Achievement award 2019 (at ISEV2019 in Kyoto, Japan).

- What made you focus on extracellular vesicle research?

- I am working in the EV field already for a long time, over 20 years now. At that time I did not actively step into EV research but we were struck by the finding that membrane proteins can be transferred between antigen presenting cells and T-cells. This was quite uncommon and at that time the scientific community did not believe it was a relevant physiological effect, but merely an artefact of in vitro studies. We also did not understand how membrane proteins from T cells ended up on antigen presenting cells but triggered by our data we tried to figure out the transfer mechanism between these cells. One possibility was via EVs, such as exosomes. At that time Graca Raposo just published the research she performed at Utrecht University, showing that vesicles released by B lymphocytes have antigen presenting properties. So it was in the early days that EVs were not just regarded as waste bins to release obsolete cell products, but in fact could play an active role in intercellular communication as well. At that time we collected all known bits and pieces regarding EV biogenesis, EV release and EV isolation protocols to start a research line on the role of EVs in immune cell communication. We demonstrated that T cell-derived EVs were transferred to antigen presenting cells and that T cell-derived proteins could modulate the antigen presenting cell function. I was excited about EV-mediated intercellular communication and decided to stay into this new fascinating field. A tough decision in the early 2000s when many scientists were very skeptical, but I never regretted since I believe that EVs could be a ‘missing link’ in our understanding of intercellular communication in and between biological systems.

- What is the most exciting recent development in your lab?

- From technological point of view, it are the major improvements we are making in single vesicle-based detection and isolation. We managed to analyze, identify and even sort EV subsets by high resolution flow cytometry, thereby moving from bulk-based to individual EV-based analysis. An important step to move the EV-field forward. From biological point of view, our recent findings that EVs present in milk have strong immune modulatory- and barrier enhancing capacities hinting towards a role of these EVs in the development of the immune system and gastro-intestinal barrier of the newborn is really exciting. The fact that such EVs not only play a role in cellular communication within an organism but also between different organisms, adds a new dimension. As a biologist for me, EV-mediated inter-organism communication is one of the most exciting areas of the EV-field!

- What are the biggest challenges facing your research at the moment?

- One of the big challenges is the technical part of EV analysis and how to deal with heterogeneity of EVs. Single vesicle-based characterization is needed to decipher the role of EVs and EV subsets in health and disease. The biggest challenges are in the analysis of individual nanosized EVs and the continuous improvements of the technology needed. For example for flow cytometry-based EV analysis, as biologist you need to team up with physicists and industry to develop next generation instruments and reagents to improve the detection and discrimination of EVs. Furthermore, to increase robustness and reproducibility of flow cytometric analysis of EVs, specific standards and calibrators need to be developed, and proper reporting and controls need to be encouraged.

For the proper understanding of the physiological role of EVs and for (clinical) application of EVs, the heterogeneity of EVs is very challenging. Which EVs are responsible for the desired effect? Can this effect be attributed to a particular EV subset or do different EVs act in concert and is the desired effect the result of a concerted action? The challenge is thus to define the real functional entity. For this we need to define potency assays that can measure the mode of action of EVs and to develop robust technology to reproducibly isolate and control EV-based preparations for in vivo applications.

- What is the most rewarding part of what you do?

- The most rewarding part of what I do is to work together with very enthusiastic, talented and highly motivated people in this relatively new research field. Working in mixed teams, building bridges, making efforts to understand the language of other specialists and disciplines and to ‘translate’ the biological EV part, all with the same goal ‘trying to unveil the role of EVs in the cellular communication’ is great fun. It is a privilege to work with PhD students, postdocs and technicians that came to my group with the attitude; “I really would like to work on EVs”. Building a team, giving room to wild ideas, concepts and experiments to try to understand much better this complicated part of biology, that is what keeps me going.

- Would it be possible to use cell-derived vesicles for clinical application in the nearest 5 years?

- I am quite optimistic on that. Of course, the regulatory aspects around clinical applications of EVs need to be settled first. ISEV can play an active role in this. Besides EV applications in human also veterinary applications can play a role in moving the field fast forward. A nice example could be the application of milk-derived EVs using their intrinsic immune modulatory capacity or as drug-delivery carrier.

- Where do you see things going? What do you think will be the next big breakthrough in EV research?

- I think the next great breakthrough will be in biology. In the better understanding how biological systems communicate and in a more complete view on how cells in complex systems, such as the immune system, act in concert and define the ultimate outcome of the response. In my view EVs play a crucial role in balancing complex systems by integrating and communicating specific information. A fascinating example of this is the work by Biller et al (Science 2014), demonstrating bacterial vesicles in marine ecosystems that are assumed to play a role in the maintenance of these systems. If we dive into the fundamentals of biology and understand how these biosystems are built and maintained, we can exploit this knowledge also when these systems are disturbed, e.g. due to environmental changes.

Besides potential (therapeutic) application of EVs, e.g. in balancing chronic autoimmune diseases or allergies, the use of EVs as multi-component biomarker is an important emerging field. Many researchers and clinicians are involved in EV-based biomarker discovery in cancer and other diseases. This goes hand in hand with the development of technology for EV-based biomarker profiling. So also in these EV applications breakthroughs can be expected.

- What are not-to-do things when working with EVs?

- That is a very difficult question to answer. Rather than summing up don’ts, I think it is more important that you are well aware of what you are doing, why you are doing it, and always proper report what you did. So for example, studying an EV-enriched pellet without further purification is not wrong, but you need to report this properly and do not claim that the effect is solely EV-mediated. If you are a newcomer in the field an important pitfall is to enter this field without knowledge, buy an one-step isolation kit to isolate EVs and claim EV-mediated effects without proper controls. Similar examples can be found for flow cytometric analysis of EVs in which the fundamental principles and the limitations of the instrument are ignored. It is not difficult to generate events on any flow cytometer, but the interpretation of the events is difficult. That also holds true for inappropriate use of nanoparticle-tracking analysis. In general, you should be well aware of the characteristics of your sample and of the possibilities and limitations of the technology or platform used to measure your sample before you can start interpreting data. Together with proper controls and comprehensive description of the experimental design this will contribute to robust and reproducible EV-research. Currently several ISEV position papers, the updated MISEV guidelines (the minimal requirements of reporting), the EV-track knowledge base and a reporting framework for flow cytometric EV analysis are available to guide the design of proper experiments and proper reporting. These tools are very helpful, not only for newcomers in the field.