Article

Tanycytes of the Hypothalamic Median Eminence Form a Diet-Responsive Neurogenic Niche

Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Nature Neuroscience (Impact Factor: 14.98). 03/2012; 15(5):700-2. DOI: 10.1038/nn.3079
Source: PubMed

ABSTRACT Adult hypothalamic neurogenesis has recently been reported, but the cell of origin and the function of these newborn neurons are unknown. Using genetic fate mapping, we found that median eminence tanycytes generate newborn neurons. Blocking this neurogenesis altered the weight and metabolic activity of adult mice. These findings reveal a previously unreported neurogenic niche in the mammalian hypothalamus with important implications for metabolism.

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    • "We observed no long-term differences in body weight gained between sham and irradiated animals fed normal chow in either our male (sham treatment: n=8; irradiation treatment: n=12) or female (sham treatment: n=12; irradiation treatment: n=12) cohorts (Figure 3C). In contrast, HFD-fed female mice showed a significant reduction in weight gain following irradiation relative to sham controls, as previously reported (Lee et al., 2012). At 9 weeks post-treatment, irradiated female mice receiving HFD (n=10) had 32±4% increase in weight gain relative to sham controls (n=9), which showed a 52±6% increase in weight gain (student t-test: p=0.028 Figure 3C). "
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    Frontiers in Neuroscience 06/2014; DOI:10.3389/fnins.2014.00157 · 3.70 Impact Factor
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    • " find evidence that dividing cells adopted a neuronal phenotype in this region ( Hazlerigg et al . , 2013 ) . Interesting , from other model systems there is some evidence that blockade of cell division in the mediobasal hypothalamus using anti - mitotic compounds or irradiation ameliorated leptin - ( Kokoeva et al . , 2005 ) and high fat diet - ( Lee et al . , 2012 ) induced changes in metabolism , suggesting a causal role for cell division in hypothalamic function . It remains to be determined whether thyroid hormone is the critical regulator of seasonal plasticity in the adult hypothalamus . Because thyroid hormone is the critical regulator for neurogenesis in the subventricular zone of mice ( L"
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    ABSTRACT: This article is part of a Special Issue “Energy Balance”. Seasonal cycles of adiposity and body weight reflecting changes in both food intake and energy expenditure are the norm in mammals that have evolved in temperate and polar habitats. Innate circannual rhythmicity and direct responses to the annual change in photoperiod combine to ensure that behavior and energy metabolism are regulated in anticipation of altered energetic demands such as the energetically costly processes of hibernation, migration, and lactation. In the last decade, major progress has been made into identifying the central mechanisms that underlie these profound long-term changes in behavior and physiology. Surprisingly they are distinct from the peptidergic and aminergic systems in the hypothalamus that have been identified in studies of the laboratory mouse and rat and implicated in timing meal intervals and in short-term responses to caloric restriction. Comparative studies across rodents, ungulates and birds reveal that tanycytes embedded in the ependymal layer of the third ventricle play a critical role in seasonal changes because they regulate the local availability of thyroid hormone. Understanding how this altered hormonal environment might regulate neurogenesis and plasticity in the hypothalamus should provide new insight into development of strategies to manage appetite and body weight.
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    • "Despite not having classical features of a neurogenic niche, median eminence tanycytes may also generate new-born neurons (Kokoeva et al., 2005; Lee et al., 2012). After a first study supporting the idea that hypothalamic neurogenesis in adult mice has a role in the control of energy-balance, including the capacity of regulating leptin-induced phosphorylation of signal transducer and activator of transcription 3 (STAT3) (Kokoeva et al., 2005), another recent work showed that median eminence tanycytes have a role in regulating the weight and metabolic activity of adult mice (Lee et al., 2012). "
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