Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.

Nik-related kinase (Nrk) is a Ser/Thr kinase and was initially discovered as a molecule that was predominantly detected in skeletal muscles during development. A recent study using Nrk-null mice suggested the importance of Nrk in proper placental development; however, the molecular mechanism remains...

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Main Authors: Yuka Morioka, Jin-Min Nam, Takashi Ohashi
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0171503&type=printable
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author Yuka Morioka
Jin-Min Nam
Takashi Ohashi
author_facet Yuka Morioka
Jin-Min Nam
Takashi Ohashi
author_sort Yuka Morioka
collection DOAJ
description Nik-related kinase (Nrk) is a Ser/Thr kinase and was initially discovered as a molecule that was predominantly detected in skeletal muscles during development. A recent study using Nrk-null mice suggested the importance of Nrk in proper placental development; however, the molecular mechanism remains unknown. In this study, we demonstrated that differentiated trophoblasts from murine embryonic stem cells (ESCs) endogenously expressed Nrk and that Nrk disruption led to the enhanced proliferation of differentiated trophoblasts. This phenomenon may reflect the overproliferation of trophoblasts that has been reported in enlarged placentas of Nrk-null mice. Furthermore, we demonstrated that AKT phosphorylation at Ser473 was upregulated in Nrk-null trophoblasts and that inhibition of AKT phosphorylation cancelled the enhanced proliferation observed in differentiated Nrk-null trophoblasts. These results indicated that the upregulation of AKT phosphorylation was the possible cause of enhanced proliferation observed in Nrk-null trophoblasts. The upregulation of AKT phosphorylation was also confirmed in enlarged Nrk-null placentas in vivo, suggesting that proper regulation of AKT by Nrk was important for normal placental development. In addition, our detailed analysis on phosphorylation status of AKT isoforms in newly established trophoblast stem cells (TSCs) revealed that different levels of upregulation of AKT phosphorylation were occurred in Nrk-null TSCs depending on AKT isoforms. These results further support the importance of Nrk in proper development of trophoblast lineage cells and indicate the possible application of TSCs for the analysis of differently regulated activation mechanisms of AKT isoforms.
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spelling doaj-art-7ff3a05c46f348d9a5bbf41d8c302ac92025-08-20T03:04:55ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01122e017150310.1371/journal.pone.0171503Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.Yuka MoriokaJin-Min NamTakashi OhashiNik-related kinase (Nrk) is a Ser/Thr kinase and was initially discovered as a molecule that was predominantly detected in skeletal muscles during development. A recent study using Nrk-null mice suggested the importance of Nrk in proper placental development; however, the molecular mechanism remains unknown. In this study, we demonstrated that differentiated trophoblasts from murine embryonic stem cells (ESCs) endogenously expressed Nrk and that Nrk disruption led to the enhanced proliferation of differentiated trophoblasts. This phenomenon may reflect the overproliferation of trophoblasts that has been reported in enlarged placentas of Nrk-null mice. Furthermore, we demonstrated that AKT phosphorylation at Ser473 was upregulated in Nrk-null trophoblasts and that inhibition of AKT phosphorylation cancelled the enhanced proliferation observed in differentiated Nrk-null trophoblasts. These results indicated that the upregulation of AKT phosphorylation was the possible cause of enhanced proliferation observed in Nrk-null trophoblasts. The upregulation of AKT phosphorylation was also confirmed in enlarged Nrk-null placentas in vivo, suggesting that proper regulation of AKT by Nrk was important for normal placental development. In addition, our detailed analysis on phosphorylation status of AKT isoforms in newly established trophoblast stem cells (TSCs) revealed that different levels of upregulation of AKT phosphorylation were occurred in Nrk-null TSCs depending on AKT isoforms. These results further support the importance of Nrk in proper development of trophoblast lineage cells and indicate the possible application of TSCs for the analysis of differently regulated activation mechanisms of AKT isoforms.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0171503&type=printable
spellingShingle Yuka Morioka
Jin-Min Nam
Takashi Ohashi
Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
PLoS ONE
title Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
title_full Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
title_fullStr Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
title_full_unstemmed Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
title_short Nik-related kinase regulates trophoblast proliferation and placental development by modulating AKT phosphorylation.
title_sort nik related kinase regulates trophoblast proliferation and placental development by modulating akt phosphorylation
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0171503&type=printable
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AT jinminnam nikrelatedkinaseregulatestrophoblastproliferationandplacentaldevelopmentbymodulatingaktphosphorylation
AT takashiohashi nikrelatedkinaseregulatestrophoblastproliferationandplacentaldevelopmentbymodulatingaktphosphorylation