Our goal has been to understand the physiological and molecular aspects of PROS by investigating various factors that we hypothesize play a role in the onset and severity of PROS, including the type of PIK3CA mutation, the timing of mutation acquisition, and the specific cell type that first acquires the mutation.
For our first objective, we focused on understanding how different PIK3CA mutations, specifically H1047R, E545K, and E726K, affect endothelial cells at the molecular level. Endothelial cells line the blood vessels, and they are commonly affected in PROS. We achieved this by isolating and analyzing these cells from special mouse models and patients. We observed that these mutations activated signaling pathways, like the PI3K and MAPK pathways, in distinct ways, and that they responded differently to various stimuli. RNA sequencing provided a transcriptomic profile for each mutation, revealing distinct deregulated biological pathways and enhancing our understanding of variant-specific contributions to disease pathogenesis.
For our second objective, we began modeling and exploring how PROS developed over time and in different tissues by comparing the strong mutations (H1047R and E545K) with the weaker variant (E726K) using specially modified mouse models. We found significant differences in embryonic survival and blood vessel development. Also, expressing these mutations at different developmental stages led to different phenotypes, emphasizing how both timing and type of mutation could influence the overall disease outcome. We also used an ear skin model to investigate the impact of PIK3CA mutations on lymphatic overgrowth. Our findings showed that the H1047R, E545K, and E726K mutations display distinct pathogenic profiles across multiple in vivo models of PROS, influencing embryonic development, vascular integrity, and tissue-specific overgrowth in unique ways.
In summary, our results have shown that different PIK3CA variants have unique characteristics that shape their contribution to the disease.
We have shared our findings at scientific conferences and workshops, reaching academic communities, clinicians, and patients. A significant achievement was launching the Emerging Leaders in Biomedicine symposium series in Barcelona, fostering collaboration among early-career biomedical researchers. This project has also fostered partnerships with pharmaceutical companies, and we are actively working to publish our studies in open-access journals and repositories to make our findings widely available. Overall, the knowledge gained from this research enhances our understanding of PI3K signaling and sets the stage for future treatments to improve the lives of those affected by PROS.
