Notch-Dependent Pituitary SOX2+ Stem Cells Exhibit a Timed Functional Extinction in Regulation of the Postnatal Gland

• Main Authors: Xiaoyan Zhu, Jessica Tollkuhn, Havilah Taylor, Michael G. Rosenfeld
• Format: Article
• Language: English
• Published: Elsevier 2015-12-01
• Series: Stem Cell Reports
• Online Access: http://www.sciencedirect.com/science/article/pii/S2213671115003343

Although SOX2+ stem cells are present in the postnatal pituitary gland, how they are regulated molecularly and whether they are required for pituitary functions remain unresolved questions. Using a conditional knockout animal model, here we demonstrate that ablation of the canonical Notch signaling in the embryonic pituitary gland leads to progressive depletion of the SOX2+ stem cells and hypoplastic gland. Furthermore, we show that the SOX2+ stem cells initially play a significant role in contributing to postnatal pituitary gland expansion by self-renewal and differentiating into distinct lineages in the immediate postnatal period. However, we found that within several weeks postpartum, the SOX2+ stem cells switch to an essentially dormant state and are no longer required for homeostasis/tissue adaptation. Our results present a dynamic tissue homeostatic model in which stem cells provide an initial contribution to the growth of the neonatal pituitary gland, whereas the mature gland can be maintained in a stem cell-independent fashion.