Specialized niches support the lifelong maintenance and function of tissue-specific
stem cells. Adult neural stem cells in the ventricular-subventricular zone (V-SVZ)
contact the cerebrospinal fluid (CSF), which flows through the lateral ventricles.
A largely ignored component of the V-SVZ stem cell niche is the lateral ventricle
choroid plexus (LVCP), a primary producer of CSF. Here we show that the LVCP, in addition
to performing important homeostatic support functions, secretes factors that promote
colony formation and proliferation of purified quiescent and activated V-SVZ stem
cells and transit-amplifying cells. The functional effect of the LVCP secretome changes
throughout the lifespan, with activated neural stem cells being especially sensitive
to age-related changes. Transcriptome analysis identified multiple factors that recruit
colony formation and highlights novel facets of LVCP function. Thus, the LVCP is a
key niche compartment that translates physiological changes into molecular signals
directly affecting neural stem cell behavior.