Brain ependymocytes in neurogenesis and maintaining integrity of blood-cerebrospinal fluid barrier

Abstract

Here we review the physiology of brain ependymocytes which produce cerebrospinal fluid, regulate neurogenic niches, and contribute to neurogenesis in health and disease. We particularly focus on cilia as these organelles are pivotal to ensure the normal functioning of ependymocytes. The functional activity of ependymocytes is largely defined by their localisation in the central nervous system. Further studies of ependymal cell biology are required to better understand the mechanisms of neurological disorders and to discover novel therapeutic strategies aimed at correcting neurodegeneration and aberrant development of the brain.

Current progress and challenges in the development of brain tissue models: How to grow up the changeable brain in vitro?

“…BCSFB controls ultrafiltration of blood plasma components from capillaries into the lumen of brain ventricles and production of CSF, secretion of some peptides and proteins into CSF as well as absorption of various substances from CSF. 41 For instance, up to 20% of CSF in the human brain originates from the brain interstitial fluid (ISF), and there is an important mechanism to remove metabolites and potentially toxic substances from the brain parenchyma: CSF goes into the brain tissue alongside the perivascular spaces up to microvessels, then due to activity of AQP4 in perivascular astrocytes CSF is transferred into the interstitial space to refill ISF. 42 Finally, the fluid leaves the brain tissue at the level of veins: through ependymal cells into ventricles, via pia-glial membranes into the surface of the brain and spinal cord, and by means of glymphatic system into extracranial lymph nodes.…”

“… 150 As an example, SVZ enriched with neural stem cells (NSCs) and neuronal progenitor cells (NPCs) is fenced off the CSF via the layer of ependymal cells ( Figure 1 ), which are “sister” cells to the NSCs and are able to provide trophic and metabolic support, to participate in the synthesis and secretion of CSF, to mediate steroidogenesis, and to regulate the selective passage of water. 41 Specialized EpCs known as tanycytes locate in the third and fourth ventricles and communicate with the hypothalamic median eminence serving as a diet-regulated neurogenic niche important for the feeding behavior and metabolic control. 151 EpCs coordinate CFS dynamics in (patho)physiological conditions by generating a directional CSF flow controlled by ciliary beating.…”