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Loss of Neurogenesis in Aging Hydra.
- Source :
-
Developmental neurobiology [Dev Neurobiol] 2019 May; Vol. 79 (5), pp. 479-496. Date of Electronic Publication: 2019 Apr 26. - Publication Year :
- 2019
-
Abstract
- In Hydra the nervous system is composed of neurons and mechanosensory cells that differentiate from interstitial stem cells (ISCs), 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&#95;CS, this loss irreversibly leads to aging and animal death. Within four weeks, Ho&#95;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 downregulation of classical neuronal markers during aging but also shows the upregulation of putative regulators of neurotransmission and neurogenesis such as AHR, FGFR, FoxJ3, Fral2, Jagged, Meis1, Notch, Otx1, and TCF15. The switch of Fral2 expression from neurons to germ cells suggests that in aging animals, the neurogenic program active in ISCs is re-routed to germ cells, preventing de novo neurogenesis and impacting animal survival.<br /> (© 2019 The Authors. Developmental Neurobiology Published by Wiley Periodicals, Inc.)
- Subjects :
- Aging pathology
Animals
Cold Temperature
Eating physiology
Gene Expression
Hydra cytology
Movement physiology
Nerve Degeneration pathology
Nerve Degeneration physiopathology
Neurons cytology
Neurons pathology
Neurons physiology
Stem Cells cytology
Stem Cells pathology
Stem Cells physiology
Aging physiology
Hydra physiology
Neurogenesis physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1932-846X
- Volume :
- 79
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Developmental neurobiology
- Publication Type :
- Academic Journal
- Accession number :
- 30912256
- Full Text :
- https://doi.org/10.1002/dneu.22676