GFAP-expressing cells in the adult hypothalamus can generate multiple neural cell lineages in vitro.

Adult neural stem cells (NSCs) located in the two canonical neurogenic niches, the subventricular zone (SVZ) and the subgranular zone (SGZ), express the glial fibrillary acidic protein (GFAP). Recently, proliferative activity has been described in the hypothalamus although the characterization of hypothalamic neural stem/progenitor cells (NSPCs) is still uncertain. We therefore investigated whether hypothalamic GFAP-positive cells, as in the SVZ and SGZ, also have neurogenic potential.

Multiparametric MR Evaluation of the Photoperiodic Regulation of Hypothalamic Structures in Sheep.

Most organisms on earth, humans included, have developed strategies to cope with environmental day-night and seasonal cycles to survive. For most of them, their physiological and behavioral functions, including the reproductive function, are synchronized with the annual changes of day length, to ensure winter survival and subsequent reproductive success in the following spring. Sheep are sensitive to photoperiod, which also regulates natural adult neurogenesis in their hypothalamus.

Seasonal remodeling of the progenitor pool and its distribution in the ewe mediobasal hypothalamus.

Recent studies have reported the presence of adult neurogenesis in the arcuate nucleus periventricular space (pvARH) and in the median eminence (ME), two structures involved in reproductive function. In sheep, a seasonal mammal, decreasing daylight in autumn induces a higher neurogenic activity in these two structures. However, the different types of neural stem and progenitor cells (NSCs/NPCs) that populate the arcuate nucleus and median eminence, as well as their location, have not been evaluated.

Selective Depletion of Adult GFAP-Expressing Tanycytes Leads to Hypogonadotropic Hypogonadism in Males.

In adult mammals, neural stem cells are localized in three neurogenic regions, the subventricular zone of the lateral ventricle (SVZ), the subgranular zone of the dentate gyrus of the hippocampus (SGZ) and the hypothalamus. In the SVZ and the SGZ, neural stem/progenitor cells (NSPCs) express the glial fibrillary acidic protein (GFAP) and selective depletion of these NSPCs drastically decreases cell proliferation and . In the hypothalamus, GFAP is expressed by α-tanycytes, which are specialized radial glia-like cells in the wall of the third ventricle also recognized as NSPCs.