MPI Campus Seminar: Development of a complex fluid flow in the third ventricle of the brain

The four ventricles of the mammalian brain are interconnected cavities that contain the cerebral spinal fluid (CSF). Along the walls of the ventricles, ependymal cells move the CSF via the whip-like movement of their motile cell protrusions called cilia. The direction of the cilia beating determines the near wall flow direction and is regulated by planar polarization of ependymal cells. In the murine lateral ventricles (LV), the inter- and intracellular interaction of planar cell polarity (PCP) proteins during early postnatal development enables the polarization of each ependymal cell. Gradually the entire LV wall polarizes from posterior to anterior. We show that the cells within the walls of the ventral third ventricle (v3V) that display a complex near wall flow pattern develop in a region-specific manner. Furthermore, via in situ hybridization at postnatal day 3 (P3) we show evidence for a possible involvement of the Wnt - signaling pathway and the Fat-Ds pathway in the regionalized development and polarization of the v3V wall. Many components of these pathways are expressed in a regionalized manner in ependymal cells and could thus be biological cues for the development of the complex v3V flow pattern.