The team today
The PhD students currently working at the lab are Laura Pirard, Liesbeth Van Hassel, Sarah Vellemans, Zhuo Zhang and Alexandra Spinel.
Apolline Goudmaeker and Gilles Tinant are in the process of writing and Aline Ferain will defend her thesis in a few weeks.
In 2022-2023, five master students are helping the team (Alice Valembois, Caroline Rosier, Mathilde van Hamme, Gracia Reyes, Delphine Decloux)
And all that is of course in collaboration with the other members of the BNTE Team !
Thanks a lot everyone !
About the current and new projects :
1 - Environmental pollutants as endocrine and lipid metabolism disruptors
The aim of the project of Laura Pirard (bioengineer) is to determine the impact of environmental stressors, individually and in combination, on adipose tissue function, using the novel ex vivo approach of precision-cut adipose tissue slices from Northern elephant seals (NES) (Mirounga angustirostris) that we have recently developed in our lab. Specifically, Laura examines the metabolic and molecular impacts of elevated stress hormones, environmental pollutants and hydrostatic pressure (as experienced by marine mammals during deep diving) on sub-cutaneous adipose tissue (blubber). Because of its accessibility, physiology and natural life history, the NES represents an excellent model to investigate the impact of stressors on adipose tissue biology. Laura has among others shown that stress hormones exhibit an interacting, blubber layer-dependent, effect on adipose tissue biology (lipolysis, adipokine expression and secretion), antioxidant defense and persistent organic pollutants (POPs) release. She is now investigating how POPs can interact with the effects of stress hormones is shallow water or during deep dives. To do so, Laura is culturing her tissues in a hyperbaric chambers (collaboration with Jean-François Rees) at levels of hydrostatic pressure mimicking shallow (0.1 megapascal or MPa) and deep-sea (5-15 MPa) environments in order to test the potential interacting effects of pressure with stress hormones. In parallel, Laura is using precision-cut adipose tissue slices of pig as a benchmark to test the most relevant combination of stressors in a terrestrial mammal. Results have among others emphasized the impact of POPs on adipose tissue lipolysis. This project is conducted in collaboration with the University of California at Santa Cruz, the Sonoma State University and the University of the Pacific (USA).
The project of Alexandra Spinel (Vet) (co-supervision with Pierre Blévin, Akvaplan-niva Research Institute, Norway), who is just starting as a PhD student in our lab, aims at understanding toxicological responses to multiple stressors in killer whales (Orcinus orca) by combining lab and field-based studies. Alexandra will develop an alternative methodology through an ex vivo precision-cut adipose tissue slice (PCATS) model and use it to characterize toxicogenomic responses to pollutants and stress. In addition, correlative field studies will be conducted to assess potential combined effects with pollutants and stress. The parallel study design will enable direct comparisons between both approaches, to examine whether responses observed ex vivo can be also reflected in correlative field studies.
Liesbeth Van Hassel (biologist) (PhD in co-supervision with Myra Finkelstein, University of California, Santa Cruz) is investigating the digestive fate of plastics and post-absorption impact of plastic-associated chemicals on seabird endocrine system, using the northern fulmar (Fulmarus glacialis) – a member of the Procellariiform order and known for experiencing a very high incidence of plastic ingestion (~80% incidence) – as a model. Liesbeth has developed an in vitro Procellariiform digestive system model to study the release of chemicals from ingested plastics trapped in seabird stomachs. Results showed that the digestive process stimulated the release of additives and adsorbed pollutants from the plastic particles in a polymer-dependent way. The composition of the food, and in particular the lipidic profile significantly influenced the release of chemicals from the plastic matrix. Liesbeth is now working in California at the University of California, Santa Cruz and the Reproduction Unit of the San Diego Zoo to measure the activation of northern fulmar estrogen receptors in the presence of plastic-associated chemicals (plastic additives and POPs released during the digestive process) to assess the biological impact of plastic ingestion.
2 – Polyunsaturated fatty acids in health and diseases
Several types of seed oils contain interesting bioactive polyunsaturated fatty acids, which have been shown to exert health promoting effects against cancer, inflammation, obesity, atherosclerosis and oxidative stress. However, many aspects linked to the bioavailability of such compounds remain to be unraveled. The PhD of Sarah Vellemans (bioengineer) (co-supervision with Nathalie Delzenne, LDRI, UCLouvain) specifically focuses on those questions, with in vitro and in vitro approaches investigating the fate of the oils in the digestive tract, the precolonic digestion of triglycerides rich in those specific fatty acids, their absorption and biotransformation by enterocytes as well as their interaction with the gut microbiota.
Cathy Debier is also collaborating with Yvan Larondelle on his projects regarding fatty acids and cancer. They co-supervise the PhD of Zhuo Zhang who is studying the toxicity of specific polyunsaturated fatty acids against cancer cells, using an original model : the zebrafish. Zhuo investigates in vitro the molecular mechanisms underlying the cytotoxicity of bioactive fatty acids on zebrafish melanoma cell line (ZMEL1 cells). The in vitro results will then be validated in vivo on Casper zebrafish (which are completely transparent) transplanted with fluorescently marked ZMEL1 cells to monitor tumor development in presence or absence of bioactive fatty acids, with the possibility of making quantitative measurements.