Induction of unfolded protein response during neuronal induction of rat bone marrow stromal cells and mouse embryonic stem cells.
When we treated rat bone marrow stromal cells (rBMSCs) with neuronal differentiation induction media, typical unfolded protein response (UPR) was observed. BIP/GRP78 protein expression was time-dependently increased, and three branches of UPR were all activated. ATF6 increased the transcription of XBP1 which was successfully spliced by IRE1. PERK was phosphorylated and it was followed by eIF2alpha phosphorylation. Transcription of two downstream targets of eIF2alpha, ATF4 and CHOP/GADD153, were transiently up-regulated with the peak level at 24 h. Immunocytochemical study showed clear coexpression of BIP and ATF4 with NeuN and Map2, respectively. UPR was also observed during the neuronal differentiation of mouse embryonic stem (mES) cells. Finally, chemical endoplasmic reticulum (ER) stress inducers, thapsigargin, tunicamycin, and brefeldin A, dose-dependently increased both mRNA and protein expressions of NF-L, and, its expression was specific to BIP-positive rBMSCs. Our results showing the induction of UPR during neuronal differentiations of rBMSCs and mES cells as well as NF-L expression by ER stress inducers strongly suggest the potential role of UPR in neuronal differentiation.
Cho
Yoon Mi
YM
Department of Biochemistry, 2MRC for Cell Death Disease Research Center, Korea.
Jang
Yoon Seong
YS
Jang
Young Min
YM
Chung
Sang Mi
SM
Kim
Ho Shik
HS
Lee
Jeong Hwa
JH
Jeong
Seong Whan
SW
Kim
In Kyung
IK
Kim
Jung Jin
JJ
Kim
Kwang Soo
KS
Kwon
Oh Joo
OJ