Hypothalamic Tanycytes: A Key Component of Brain–Endocrine Interaction

Rodríguez, Estéban M.; Blázquez, Juan Luis; Pastor, Francisco E.; Peláez, B; Peña, P.; Peruzzo, Bruno; Amat, P

doi:10.1016/s0074-7696(05)47003-5

Cited by 423 publications

(521 citation statements)

References 243 publications

(424 reference statements)

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“…Both have a soma located near the ventricle and a long elongated projection to a blood vessel [38][39][40][41] ; both are thought to derive from embryonic radial glia 5,14,42 ; both express Nestin and divide infrequently. Intriguingly, in the unchallenged mouse, a-tanycytes do not share the highly active neurogenic properties of the type B1 astrocyte, but instead are gliogenic (this paper; also see Wang et al 5 ).…”

Section: Discussionmentioning

confidence: 99%

“…Hypothalamic tanycytes resemble embryonic radial glia, with a cell body at the ventricular zone and a long basally extending process, their morphology well-suited to their postulated role as modulators of neuroendocrine activity and homeostasis (reviewed in [13][14][15][16] ). Within the hypothalamus, tanycyte cell bodies are strictly localised to the central and posterior hypothalamus (level of the median eminence and premammillary nucleus, respectively).…”

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confidence: 99%

“…Morphological studies have mapped and defined subpopulations of tanycytes according to their position and process projection. Ventral-most b-tanycytes line the infundibulum and median eminence, while adjacent a-tanycytes line regions of the ventricular zone (VZ) that are adjacent to hypothalamic nuclei and project laterally, contacting capillaries and neurons of the arcuate and ventromedial nuclei en passant 14,18,19 .…”

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confidence: 99%

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α-Tanycytes of the adult hypothalamic third ventricle include distinct populations of FGF-responsive neural progenitors

et al. 2013

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Emerging evidence suggests that new cells, including neurons, can be generated within the adult hypothalamus, suggesting the existence of a local neural stem/progenitor cell niche. Here, we identify a-tanycytes as key components of a hypothalamic niche in the adult mouse. Long-term lineage tracing in vivo using a GLAST::CreER T2 conditional driver indicates that a-tanycytes are self-renewing cells that constitutively give rise to new tanycytes, astrocytes and sparse numbers of neurons. In vitro studies demonstrate that a-tanycytes, but not b-tanycytes or parenchymal cells, are neurospherogenic. Distinct subpopulations of a-tanycytes exist, amongst which only GFAP-positive dorsal a2-tanycytes possess stem-like neurospherogenic activity. Fgf-10 and Fgf-18 are expressed specifically within ventral tanycyte subpopulations; a-tanycytes require fibroblast growth factor signalling to maintain their proliferation ex vivo and elevated fibroblast growth factor levels lead to enhanced proliferation of a-tanycytes in vivo. Our results suggest that a-tanycytes form the critical component of a hypothalamic stem cell niche, and that local fibroblast growth factor signalling governs their proliferation.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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α-Tanycytes of the adult hypothalamic third ventricle include distinct populations of FGF-responsive neural progenitors

et al. 2013

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“…TSH-mediated modulation of tanycyte function has emerged as the lynchpin for seasonal neuroendocrine regulation (12,15,36), reflecting the manifold actions of tanycytes as metabolic regulators (37). These include actions as leptin and glucose sensors relaying metabolic feedback signals to the arcuate nucleus (38,39) and as physical barriers controlling access of blood/CSF signals to the brain and release of hypothalamic neuropeptides to the pituitary portal system (40,41).…”

Section: Discussionmentioning

confidence: 99%

Maternal photoperiod programs hypothalamic thyroid status via the fetal pituitary gland

Miera

Bothorel

Jaeger

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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In wild mammals, offspring development must anticipate forthcoming metabolic demands and opportunities. Within species, different developmental strategies may be used, dependent on when in the year conception takes place. This phenotypic flexibility is initiated before birth and is linked to the pattern of day length (photoperiod) exposure experienced by the mother during pregnancy. This programming depends on transplacental communication via the pineal hormone melatonin. Here, we show that, in the Siberian hamster (Phodopus sungorus), the programming effect of melatonin is mediated by the pars tuberalis (PT) of the fetal pituitary gland, before the fetal circadian system and autonomous melatonin production is established. Maternal melatonin acts on the fetal PT to control expression of thyroid hormone deiodinases in ependymal cells (tanycytes) of the fetal hypothalamus, and hence neuroendocrine output. This mechanism sets the trajectory of reproductive and metabolic development in pups and has a persistent effect on their subsequent sensitivity to the photoperiod. This programming effect depends on tanycyte sensitivity to thyroid stimulating hormone (TSH), which is dramatically and persistently increased by short photoperiod exposure in utero. Our results define the role of the fetal PT in developmental programming of brain function by maternal melatonin and establish TSH signal transduction as a key substrate for the encoding of internal calendar time from birth to puberty.photoperiodism | developmental programming | hypothalamus | pars tuberalis | thyroid

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“…The nestin-positive ependymal cells displayed a morphology consistent with that previously described for tanycytes lining the third ventricle of the brain and spinal cord, with apical cilia and long basal processes. 5,23,26 The nestin-positive cells were clustered mainly in the ventral and dorsal aspects of the central canal. Tanycytes located in the ependyma of the brain have neuroendocrine functions, transport small molecules between the brain and the cerebrospinal fluid (CSF), and have the potential for neurogenesis.…”

Section: Discussionmentioning

confidence: 99%

Nestin-Positive Ependymal Cells Are Increased in the Human Spinal Cord after Traumatic Central Nervous System Injury

Cawsey

Duflou

Weickert

et al. 2015

Journal of Neurotrauma

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Endogenous neural progenitor cell niches have been identified in adult mammalian brain and spinal cord. Few studies have examined human spinal cord tissue for a neural progenitor cell response in disease or after injury. Here, we have compared cervical spinal cord sections from 14 individuals who died as a result of nontraumatic causes (controls) with 27 who died from injury with evidence of trauma to the central nervous system. Nestin immunoreactivity was used as a marker of neural progenitor cell response. There were significant increases in the percentage of ependymal cells that were nestin positive between controls and trauma cases. When sections from lumbar and thoracic spinal cord were available, nestin positivity was seen at all three spinal levels, suggesting that nestin reactivity is not simply a localized reaction to injury. There was a positive correlation between the percentage of ependymal cells that were nestin positive and post-injury survival time but not for age, postmortem delay, or glial fibrillary acidic protein (GFAP) immunoreactivity. No doublelabelled nestin and GFAP cells were identified in the ependymal, subependymal, or parenchymal regions of the spinal cord. We need to further characterize this subset of ependymal cells to determine their role after injury, whether they are a population of neural progenitor cells with the potential for proliferation, migration, and differentiation for spinal cord repair, or whether they have other roles more in line with hypothalamic tanycytes, which they closely resemble.

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Hypothalamic Tanycytes: A Key Component of Brain–Endocrine Interaction

Cited by 423 publications

References 243 publications

α-Tanycytes of the adult hypothalamic third ventricle include distinct populations of FGF-responsive neural progenitors

α-Tanycytes of the adult hypothalamic third ventricle include distinct populations of FGF-responsive neural progenitors

Maternal photoperiod programs hypothalamic thyroid status via the fetal pituitary gland

Nestin-Positive Ependymal Cells Are Increased in the Human Spinal Cord after Traumatic Central Nervous System Injury

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