AKT signaling mediates IGF-I survival actions on otic neural progenitors.

BACKGROUND: Otic neurons and sensory cells derive from common progenitors whose transition into mature cells requires the coordination of cell survival, proliferation and differentiation programmes. Neurotrophic support and survival of post-mitotic otic neurons have been intensively studied, but the...

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Main Authors: Maria R Aburto, Marta Magariños, Yolanda Leon, Isabel Varela-Nieto, Hortensia Sanchez-Calderon
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2012-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3264639?pdf=render
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spelling doaj-01c398e991df433c8130255be08104872020-11-25T01:47:14ZengPublic Library of Science (PLoS)PLoS ONE1932-62032012-01-0171e3079010.1371/journal.pone.0030790AKT signaling mediates IGF-I survival actions on otic neural progenitors.Maria R AburtoMarta MagariñosYolanda LeonIsabel Varela-NietoHortensia Sanchez-CalderonBACKGROUND: Otic neurons and sensory cells derive from common progenitors whose transition into mature cells requires the coordination of cell survival, proliferation and differentiation programmes. Neurotrophic support and survival of post-mitotic otic neurons have been intensively studied, but the bases underlying the regulation of programmed cell death in immature proliferative otic neuroblasts remains poorly understood. The protein kinase AKT acts as a node, playing a critical role in controlling cell survival and cell cycle progression. AKT is activated by trophic factors, including insulin-like growth factor I (IGF-I), through the generation of the lipidic second messenger phosphatidylinositol 3-phosphate by phosphatidylinositol 3-kinase (PI3K). Here we have investigated the role of IGF-dependent activation of the PI3K-AKT pathway in maintenance of otic neuroblasts. METHODOLOGY/PRINCIPAL FINDINGS: By using a combination of organotypic cultures of chicken (Gallus gallus) otic vesicles and acoustic-vestibular ganglia, Western blotting, immunohistochemistry and in situ hybridization, we show that IGF-I-activation of AKT protects neural progenitors from programmed cell death. IGF-I maintains otic neuroblasts in an undifferentiated and proliferative state, which is characterised by the upregulation of the forkhead box M1 (FoxM1) transcription factor. By contrast, our results indicate that post-mitotic p27(Kip)-positive neurons become IGF-I independent as they extend their neuronal processes. Neurons gradually reduce their expression of the Igf1r, while they increase that of the neurotrophin receptor, TrkC. CONCLUSIONS/SIGNIFICANCE: Proliferative otic neuroblasts are dependent on the activation of the PI3K-AKT pathway by IGF-I for survival during the otic neuronal progenitor phase of early inner ear development.http://europepmc.org/articles/PMC3264639?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Maria R Aburto
Marta Magariños
Yolanda Leon
Isabel Varela-Nieto
Hortensia Sanchez-Calderon
spellingShingle Maria R Aburto
Marta Magariños
Yolanda Leon
Isabel Varela-Nieto
Hortensia Sanchez-Calderon
AKT signaling mediates IGF-I survival actions on otic neural progenitors.
PLoS ONE
author_facet Maria R Aburto
Marta Magariños
Yolanda Leon
Isabel Varela-Nieto
Hortensia Sanchez-Calderon
author_sort Maria R Aburto
title AKT signaling mediates IGF-I survival actions on otic neural progenitors.
title_short AKT signaling mediates IGF-I survival actions on otic neural progenitors.
title_full AKT signaling mediates IGF-I survival actions on otic neural progenitors.
title_fullStr AKT signaling mediates IGF-I survival actions on otic neural progenitors.
title_full_unstemmed AKT signaling mediates IGF-I survival actions on otic neural progenitors.
title_sort akt signaling mediates igf-i survival actions on otic neural progenitors.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2012-01-01
description BACKGROUND: Otic neurons and sensory cells derive from common progenitors whose transition into mature cells requires the coordination of cell survival, proliferation and differentiation programmes. Neurotrophic support and survival of post-mitotic otic neurons have been intensively studied, but the bases underlying the regulation of programmed cell death in immature proliferative otic neuroblasts remains poorly understood. The protein kinase AKT acts as a node, playing a critical role in controlling cell survival and cell cycle progression. AKT is activated by trophic factors, including insulin-like growth factor I (IGF-I), through the generation of the lipidic second messenger phosphatidylinositol 3-phosphate by phosphatidylinositol 3-kinase (PI3K). Here we have investigated the role of IGF-dependent activation of the PI3K-AKT pathway in maintenance of otic neuroblasts. METHODOLOGY/PRINCIPAL FINDINGS: By using a combination of organotypic cultures of chicken (Gallus gallus) otic vesicles and acoustic-vestibular ganglia, Western blotting, immunohistochemistry and in situ hybridization, we show that IGF-I-activation of AKT protects neural progenitors from programmed cell death. IGF-I maintains otic neuroblasts in an undifferentiated and proliferative state, which is characterised by the upregulation of the forkhead box M1 (FoxM1) transcription factor. By contrast, our results indicate that post-mitotic p27(Kip)-positive neurons become IGF-I independent as they extend their neuronal processes. Neurons gradually reduce their expression of the Igf1r, while they increase that of the neurotrophin receptor, TrkC. CONCLUSIONS/SIGNIFICANCE: Proliferative otic neuroblasts are dependent on the activation of the PI3K-AKT pathway by IGF-I for survival during the otic neuronal progenitor phase of early inner ear development.
url http://europepmc.org/articles/PMC3264639?pdf=render
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