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Scientific article
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Loss of neurogenesis in aging Hydra

Publication date2019
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 system
  • Interstitial stem cells
  • Adult de novo neurogenesis
  • Gametogenesis
  • Aging
  • Homeoprotein prdl-a
  • Neuropeptide Hym-355
  • Evolution of neurogenesis
Funding
  • Swiss National Science Foundation - 31003A_149630, 31003_169930
  • Autre - NIH R01AG037962
Citation (ISO format)
TOMCZYK, Szymon et al. Loss of neurogenesis in aging <i>Hydra</i>. In: Developmental Neurobiology, 2019. doi: 10.1002/dneu.22676
Main files (1)
Article (Accepted version)
Identifiers
ISSN of the journal1932-8451
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