Characterization of stem cells and the dynamics of neurogenesis in the adult hypothalamus. (360G-Wellcome-091201_Z_10_Z)

We have documented the existence of stem cells and provided strong evidence for the occurrence of neurogenesis in the adult hypothalamus. We now aim to test the overarching hypothesis that Fgf10-expressing (Fgf10+) tanycytes are its major neurogenic cells, and that they generate an important set of neurons and glial cells. Towards this goal, we will conduct immuno-profiling and neurosphere assays on sections and cells derived from Fgf10-lacZ reporter brains to test whether Fgf10+ tanycytes are s tem cells or lineage-restricted progenitors. To determine the exact repertoire of neurons and glials that tanycytes generate, we will quantitatively immuno-screen their daughters (which populate the arcuate and paraventricular nuclei) with antibodies that delineate neuronal and glial subtypes. To determine the rate at which tanycytes divide and generate new neural cells and the proportion of daughters that are retained, we will lineage-trace tanycytes by constitutive activation of YFP and use a combination of BrdU pulsing and immunolabelling studies to examine the rate of proliferation, differentiation and survival of YFP-expressing tanycytes and their daughters. Finally, to definitively test the contribution of tanycytes to adult neurogenesis, we will quantitatively measure the impact of conditional loss- and gain-of-Fgf10 in tanycytes, on adult hypothalamic neurogenesis.