Seasonal reorganization of hypothalamic neurogenic niche in adult sheep

Butruille, Lucile; Batailler, Martine; Mazur, Danièle; Prévot, Vincent; Migaud, Martine

doi:10.1007/s00429-017-1478-z

Cited by 23 publications

(16 citation statements)

References 105 publications

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“…Another physiological context that affects hypothalamic neurogenesis is seasonality. In sheep, the Sox2-expressing tanycyte layer appears thicker during short photoperiod and hypothalamic cell proliferation is observed (118, 119). Moreover, the expression of neural stem cell markers including Nes, Vim, Gfap , and Dcx increase in the hypothalamus compared to long photoperiod (118, 119), confirming an increase in neurogenesis.…”

Section: Modulation Of Tanycyte Gene Expression In Response To Metabomentioning

confidence: 99%

Tanycyte Gene Expression Dynamics in the Regulation of Energy Homeostasis

Langlet

2019

Front. Endocrinol.

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Animal survival relies on a constant balance between energy supply and energy expenditure, which is controlled by several neuroendocrine functions that integrate metabolic information and adapt the response of the organism to physiological demands. Polarized ependymoglial cells lining the floor of the third ventricle and sending a single process within metabolic hypothalamic parenchyma, tanycytes are henceforth described as key components of the hypothalamic neural network controlling energy balance. Their strategic position and peculiar properties convey them diverse physiological functions ranging from blood/brain traffic controllers, metabolic modulators, and neural stem/progenitor cells. At the molecular level, these functions rely on an accurate regulation of gene expression. Indeed, tanycytes are characterized by their own molecular signature which is mostly associated to their diverse physiological functions, and the detection of variations in nutrient/hormone levels leads to an adequate modulation of genetic profile in order to ensure energy homeostasis. The aim of this review is to summarize recent knowledge on the nutritional control of tanycyte gene expression.

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Section: Modulation Of Tanycyte Gene Expression In Response To Metabomentioning

confidence: 99%

Tanycyte Gene Expression Dynamics in the Regulation of Energy Homeostasis

Langlet

2019

Front. Endocrinol.

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“…In tanycytes, the cytoskeletal proteins vimentin and neural cell adhesion molecule show reduced expression in SP compared to LP in hamsters, which is associated with changes in melatonin but not sex steroids. Morphological studies in sheep have demonstrated the increased expression of these structural markers during the winter season instead, associated to an increase in the thickness of the tanycytic nuclear layer, junctions between cells and tanycytes protrusions into the 3V at the arcuate nucleus level (ß1 tanycytes), reinforcing the view that such changes occur as a consequence of the seasonal response associated to the season of breeding (ie, sex steroid‐dependent process).…”

Section: Seasonal Structural Remodelling In Tanycytesmentioning

confidence: 90%

“…Subsequent to the initial demonstration in mice and rats that tanycytes comprise a population of stem cells that can be induced to proliferate (as assessed by bromodeoxyuridine incorporation) by growth factors such as basic fibroblast growth factor (bFGF) and ciliary neurotrophic factor (CNTF), the stem cell niche of the MBH has been described in other mammals, including sheep and humans (Figure B). This topic has been extensively reviewed recently .…”

Section: Tanycytes As Stem Cells: Does Hypothalamic Cell Proliferatiomentioning

confidence: 99%

An integrative view of mammalian seasonal neuroendocrinology

Dardente

Wood

Ebling

et al. 2019

J Neuroendocrinology

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Seasonal neuroendocrine cycles that govern annual changes in reproductive activity, energy metabolism and hair growth are almost ubiquitous in mammals that have evolved at temperate and polar latitudes. Changes in nocturnal melatonin secretion regulating gene expression in the pars tuberalis (PT) of the pituitary stalk are a critical common feature in seasonal mammals. The PT sends signal(s) to the pars distalis of the pituitary to regulate prolactin secretion and thus the annual moult cycle. The PT also signals in a retrograde manner via thyroid‐stimulating hormone to tanycytes, which line the ventral wall of the third ventricle in the hypothalamus. Tanycytes show seasonal plasticity in gene expression and play a pivotal role in regulating local thyroid hormone (TH) availability. Within the mediobasal hypothalamus, the cellular and molecular targets of TH remain elusive. However, two populations of hypothalamic neurones, which produce the RF‐amide neuropeptides kisspeptin and RFRP3 (RF‐amide related peptide 3), are plausible relays between TH and the gonadotrophin‐releasing hormone‐pituitary‐gonadal axis. By contrast, the ways by which TH also impinges on hypothalamic systems regulating energy intake and expenditure remain unknown. Here, we review the neuroendocrine underpinnings of seasonality and identify several areas that warrant further research.

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“…[111][112][113][114][115][116] Moreover, seasonal differences exist in hypothalamic cell proliferation [117][118][119] and neuronal differentiation. 114,120 Although the functional significance of this restructurating remains to be demonstrated, seasonal histogenesis has been proposed as a mechanism for endogenous timing. 121 It could be speculated that, in MPP, pools of proliferating cells differently programmed during gestation react differently to the same photoperiodic signal perceived in adults.…”

Section: How Doe S Hyp Othal Amic T3 Ac T On S E a Sonal Reproduc Tmentioning

confidence: 99%

“…Tanycytes express proliferation and differentiation markers under seasonal (eg, vimentin, nestin) and T3‐mediated control (eg, shh ) and have been proposed as the substrate for neurogenic activity in the hypothalamus, stimulated by metabolic cues and growth factors . Moreover, seasonal differences exist in hypothalamic cell proliferation and neuronal differentiation . Although the functional significance of this restructurating remains to be demonstrated, seasonal histogenesis has been proposed as a mechanism for endogenous timing .…”

Section: How Does Hypothalamic T3 Act On Seasonal Reproduction?mentioning

confidence: 99%

Maternal photoperiodic programming enlightens the internal regulation of thyroid‐hormone deiodinases in tanycytes

Miera

2019

J Neuroendocrinology

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Seasonal rhythms in physiology are widespread among mammals living in temperate zones. These rhythms rely on the external photoperiodic signal being entrained to the seasons, although they persist under constant conditions, revealing their endogenous origin. Internal long‐term timing (circannual cycles) can be revealed in the laboratory as photoperiodic history‐dependent responses, comprising the ability to respond differently to similar photoperiodic cues based on prior photoperiodic experience. In juveniles, history‐dependence relies on the photoperiod transmitted by the mother to the fetus in utero, a phenomenon known as “maternal photoperiodic programming” (MPP). The response to photoperiod in mammals involves the nocturnal pineal hormone melatonin, which regulates a neuroendocrine network including thyrotrophin in the pars tuberalis and deiodinases in tanycytes, resulting in changes in thyroid hormone in the mediobasal hypothalamus. This review addresses MPP and discusses the latest findings on its impact on the thyrotrophin/deiodinase network. Finally, commonalities between MPP and other instances of endogenous seasonal timing are considered, and a unifying scheme is suggested in which timing arises from a long‐term communication between the pars tuberalis and the hypothalamus and resultant spontaneous changes in local thyroid hormone status, independently of the pineal melatonin signal.

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Seasonal reorganization of hypothalamic neurogenic niche in adult sheep

Cited by 23 publications

References 105 publications

Tanycyte Gene Expression Dynamics in the Regulation of Energy Homeostasis

Tanycyte Gene Expression Dynamics in the Regulation of Energy Homeostasis

An integrative view of mammalian seasonal neuroendocrinology

Maternal photoperiodic programming enlightens the internal regulation of thyroid‐hormone deiodinases in tanycytes

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