Migrazione e amplificazione dei progenitori degli oligodendrociti nel cervelletto

It has long been known as oligodendrocytes participate to the development of the central nervous system, producing myelin, a lipid-rich wrapping around axons, which modulates the intensity of signal propagation of the central nervous system. Nevertheless, there are still many unknown aspects of this lineage of cells, such as how they arrive in the cerebellum. In our work we have shown that, in mice, during embryonic development, there is a density gradient of the progenitors of oligodendrocytes (OPCs) which decreases moving from the midbrain to the cerebellum, in agreement with the theory of a migration from the midbrain to the cerebellar region. However, the apical part of the cerebellum begins to be populated only at birth. Furthermore, the fact that they are mostly located at the base of the cerebellum and that, at this age, the ventricular germinal epithelium is not active, suggests that OPCs are most probably migrated from the outside rather than generated by resident progenitors in the cerebellar niches. We then showed the amplification of the OPCs during postnatal development: we quantified, for different ages, cells that are slowing their proliferation and going to maturation. We observed that they are present in greater quantities in deep white matter than the other layers. This observation supports our hypothesis that cells enter in the cerebellum through the deep white matter, which there are mature cells that have come in the cerebellum in earlier times than the other. We chose to analyze, in addition, clones of OPCs, sisters cell groups identified by the use of transgenic mice, where each cell can express only one of four fluorescent protein that persist in the cell progeny. The data obtained suggest that each OPCs migrate in the cerebellar territory during the first weeks until you reach a particular site, in which begins to proliferate colonizing the surrounding territory. One of the most interesting aspects of this observation is that different clones don't mix, indeed, is not found, except for rare cases, different color cells that invade the territory occupied by a clone.