Environmental factors such as endocrine disrupting chemicals (EDC) are suspected to explain the rapidly increasing number of cases of Multiple Sclerosis (MS), a disease related to the progressive disruption of the protective myelin sheath that covers nerve fibers (Fig. 1A, Top). Our collaborators Sylvie Remaud (neuroendocrinologist, Musée National d’Histoire Naturelle) and Bernard Zalc (Neuroscientist, Institut du Cerveau et de la Moelle épinière) have obtained preliminary data showing that flame retardants or fluorosurfactants (PFAS) affect the myelin formation process and remyelination in vivo. These lipophilic components could indeed accumulate in the lipid-rich structures like the myelin sheath (Fig. 1A, Bottom) and modify its membrane composition, as well as its mechanical properties, thus compromising its capability to coat long projecting axons.
The internship project aims at studying the mechanical properties of membranes affected or not by PFAS using biophysical approaches. We will form Giant Vesicles with lipids extracted of the myelin of animals exposed or not to PFAS, using standard methods well mastered in the group1. The elastic modulus, the interlayer friction and the lysis tension (tension at which membrane ruptures) of these liposomes will be measured using tube pulling experiments and micropipette aspiration, respectively (Fig. 1B) techniques that the team have contributed to develop2. In parallel, our collaborators will use lipidomics to analyze the lipids composition of the myelin of these animals exposed or not to PFAS.
