Meet our EDC-MixRisk scientists working behind the scenes and learn more about their work. This time Maria Jönsson is in the spotlight. She is an assistant professor, group leader and PI in the Uppsala University, Environmental Toxicology unit. The primary objective of her research group is to examine developmental effects of chemicals in vertebrates in vivo, including identification of molecular targets and mechanisms of action. Dr. Jönsson is a WP Leader in Work Package 5 (identification of adverse outcome pathways) in EDC-MixRisk.
The chemicals studied in EDC-MixRisk are mixtures of common chemicals that have been detected in serum in pregnant women and associated with risk for adverse effects in their children. These effects are related to sexual development, metabolism and growth, and neurodevelopment (S, G, and N mixtures, respectively). We are using two in vivo models (zebrafish and chicken) to examine how early exposure to the S0 and G0 mixtures affect sexual development and metabolism. More precisely we are looking at effects on development of reproductive organs and adipose tissue by the mixtures. We are also studying how the mixtures affect molecular pathways that are important for cell fate and cell turnover (Wnt/β-catening-signaling and p53/apoptosis) in zebrafish embryos.
What have you discovered so far and what your first results indicate?
We found that embryonic and larval exposure to the first growth mixture (G0) increased the number of adipocytes in zebrafish larvae. The same mixture reduced Wnt/β-catenin signaling in zebrafish embryos and preliminary data indicate that it also increases apoptosis in these embryos. These results indicate that G0 affects cell survival and cell fate in vivo and that one cell type in target is the adipocyte (its precursors). Our group did not find any effect of S0 on sex organ development in zebrafish or chicken.
What are the potential implications of your findings?
Our results suggest that ubiquitously present chemical mixtures have the capacity to stimulate adipogenesis (the process of fat cell differentiation) in humans and in wildlife at realistic exposure levels. The results are in line with in vitro results and studies conducted by other partners in the project so far. This is highly interesting in view of that the G0 mixture was composed of chemicals that were measured from the samples of pregnant women, and these chemicals correlate with low birth weight in the SELMA cohort. Low birth weight is associated with an increased risk for metabolic disorders.