Vincent van PeschFlasse, BenjaminBenjaminFlasse2025-05-142025-05-142025-05-142021https://hdl.handle.net/2078.2/23673Multiple Sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system (CNS) of the young adult whose pathogenesis remains unknown. MS is characterised by an invasion of CNS by immune cells, microglial activation and the destruction of the myelin sheath produced by oligodendrocytes, leading to neuronal death. While current treatments are mainly focused on the inflammatory aspects of MS, there is an unmet need for therapy promoting oligodendrocyte differentiation, which is stalled during the disease. Oligodendrocyte differentiation is a finely tuned and complex process, yet incompletely understood. Oligodendrocytes, as other cells, release in the environment extracellular vesicles (EVs) that are recognized for playing an active role in intercellular communication. It is still not clear whether the EVs released by oligodendrocytes in physiological or pathological conditions and at distinct development stages could have a specific effect on oligodendrocyte development. We hypothesise that oligodendrocytes influence their own differentiation, depending on the environmental context, by secreting EVs regulating differentiation. The objectives to tackle this hypothesis were firstly (1) the validation of the molecular differentiation by quantitative polymerase chain reaction (qPCR) on an oligodendroglial cell model (CG-4) and (2) the validation of the isolation of EVs produced by these CG-4. In a second step we strived for (3) the isolation and storage of EVs produced in proliferation upon control or ionomycin conditions, (4) the analysis of the impact of ionomycin on our molecular differentiation readout and finally (5) the study of the effect of EVs collected on CG-4 differentiation. We were able to select molecular markers by qPCR for CG-4 differentiation essential later on to monitor for the impact of treatments on CG-4 differentiation. The isolation and purity of EVs produced by CG-4 was validated through Nanoparticle Tracking Analysis, whole-protein assay and specific protein analysis by Europium-ELISA or dot-blotting methods. An ionomycin dose-response was performed on CG-4 cells, showing that subtoxic concentrations of ionomycin did not affect the differentiation of CG-4, excluding that ionomycin from ionomycin treatment-derived EVs would affect cell differentiation. The effect of EVs produced on proliferation and ionomycin conditions on CG-4 cell differentiation fate were not successfully analysed due to technical problems and the design is to be improved. Although being a first attempt with hurdles occurred on the way, the perspective of this work will allow a better understanding of the autoregulation of oligodendrocyte’s differentiation which could play a role in MS.Multiple SclerosismyelinOligodendrocyteextracellular vesiclesCG-4Oligodendrocytes progenitor cellsdifferentiationtext::thesis::master thesisthesis:32994