Summary: | Summary: The glymphatic system is a highly polarized cerebrospinal fluid (CSF) transport system that facilitates the clearance of neurotoxic molecules through a brain-wide network of perivascular pathways. Herein we have mapped the development of the glymphatic system in mice. Perivascular CSF transport first emerges in hippocampus in newborn mice, and a mature glymphatic system is established in the cortex at 2 weeks of age. Formation of astrocytic endfeet and polarized expression of aquaporin 4 (AQP4) consistently coincided with the appearance of perivascular CSF transport. Deficiency of platelet-derived growth factor B (PDGF-B) function in the PDGF retention motif knockout mouse line Pdgfbret/ret suppressed the development of the glymphatic system, whose functions remained suppressed in adulthood compared with wild-type mice. These experiments map the natural development of the glymphatic system in mice and define a critical role of PDGF-B in the development of perivascular CSF transport. : Munk et al. unravel the developmental profile of the glia-lymphatic (glymphatic) system. Glymphatic function arises in the hippocampus at postnatal day 1 in conjunction with the polarized expression of AQP4 at astrocyte endfeet. PDGF-B signaling is implicated in normal glymphatic function, and reduced signaling reduces AQP4 polarization and glymphatic influx. Keywords: cerebrospinal fluid, astrocytes, aquaporin 4, platelet-derived growth factor B, postnatal development, glymphatic system
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