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Title

Loss of neurogenesis in aging Hydra

Authors
Fisher, Kathleen
Austad, Steven
Published in Developmental Neurobiology. 2019
Abstract In Hydra the nervous system is composed of neurons and mechano‐sensory cells that differentiate from interstitial stem cells, which also provide gland cells and germ cells. The adult nervous system is actively maintained through continuous de novo neurogenesis that occurs at two distinct paces, slow in intact animals and fast in regenerating ones. Surprisingly Hydra vulgaris survive the elimination of cycling interstitial cells and the subsequent loss of neurogenesis if force‐fed. By contrast, H. oligactis animals exposed to cold temperature undergo gametogenesis and a concomitant progressive loss of neurogenesis. In the cold‐sensitive strain Ho_CS, this loss irreversibly leads to aging and animal death. Within four weeks, Ho_CS animals lose their contractility, feeding response and reaction to light. Meanwhile, two positive regulators of neurogenesis, the homeoprotein prdl‐a and the neuropeptide Hym‐355, are no longer expressed, while the “old” RFamide‐expressing neurons persist. A comparative transcriptomic analysis performed in cold‐sensitive and cold‐resistant strains confirms the down‐regulation of classical neuronal markers during aging but also shows the up‐regulation of putative regulators of neurotransmission and neurogenesis such as AHR, FGFR, FoxJ3, Fral2, Jagged, Meis1, Notch, Otx1, TCF15. The switch of Fral2 expression from neurons to germ cells suggests that in aging animals, the neurogenic program active in interstitial stem cells is re‐routed to germ cells, preventing de novo neurogenesis and impacting animal survival.
Keywords Hydra nervous systemInterstitial stem cellsAdult de novo neurogenesisGametogenesisAgingHomeoprotein prdl-aNeuropeptide Hym-355Evolution of neurogenesis
Identifiers
PMID: 30912256
Full text
Article (Author postprint) (4.9 MB) - document accessible for UNIGE members only Limited access to UNIGE (until 2020-04-02)
Other version: https://onlinelibrary.wiley.com/doi/abs/10.1002/dneu.22676
Structures
Projects FNS: 31003A_149630, 31003_169930
NIH R01AG037962
Citation
(ISO format)
TOMCZYK, Szymon et al. Loss of neurogenesis in aging Hydra. In: Developmental Neurobiology, 2019. https://archive-ouverte.unige.ch/unige:115742

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Deposited on : 2019-04-04

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