文摘
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Summary
The subventricular zone (SVZ) neural stem cell niche?contains mixed populations of stem cells, transit-amplifying cells, and migrating neuroblasts. Deciphering how endogenous signals, such as hormones, affect the balance between these cell types is essential for understanding the physiology of niche plasticity and homeostasis. We show that Thyroid Hormone (T3) and its receptor, TR¦Á1, are directly involved in maintaining this balance. TR¦Á1 is expressed in amplifying and migrating cells. In?vivo gain- and loss-of-function experiments demonstrate first, that T3/TR¦Á1 directly repress Sox2 expression, and second, that TR¦Á1 overexpression in the niche favors the appearance of DCX+ migrating neuroblasts. Lack of TR¦Á increases numbers of SOX2+ cells in the SVZ. Hypothyroidism increases proportions of cells in interphase. Thus, in the adult SVZ, T3/TR¦Á1 together favor neural stem cell commitment and progression toward a migrating neuroblast phenotype; this transition correlates with T3/TR¦Á1-dependent transcriptional repression of Sox2.
