Identification of non-canonical Wnt receptors required for Wnt-3a-induced early differentiation of human neural stem cells
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
Wnt proteins preferentially activate either β-catenin-dependent or β-cateninindependent
signals, but the activity of a particular Wnt also depends on cellular
context and receptor availability. We previously reported that Wnt-3a induces
neural differentiation of human embryonic stem cell-derived neural stem cells
(NSCs) in a β-catenin-independent manner by activating a signal involving JNK and
the AP-1 family member ATF-2. Here, we report the results of a gene silencing
approach to identify the Wnt receptors that mediate this response to Wnt-3a.
Silencing of ROR2 increased neuronal differentiation, as measured by expression
of the genes DCX, NEUROD1 and NGN1, suggesting ROR2 signals normally prevent
differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3ainduced
neuronal differentiation. However, pair-wise silencing of ROR1 and FZD4
or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as
detected by reductions in the expression of neuronal genes and
immunocytochemical detection of DCX and NEUROD1 and DCX. Ectopic expression
of these receptors in HEK 293 cells increased ATF2-dependent transcription. In
addition, ROR1 co-immunoprecipitated with FZD4 and LRP6 in transfected HEK
293 cells and colocalized with FZD4 and with LRP6 at the cell surface of
transfected L cells. Wnt-3a did not appear to affect these interactions but did alter
the interactions between LRP6 and FZD4/5. Together, these observations highlight
roles for ROR1, LRP6, FZD4 and FZD5 in neural stem cell differentiation and
provide support for a model in which dynamic interactions among these receptors
mediate Wnt-3a activation of ATF2 signaling.
signals, but the activity of a particular Wnt also depends on cellular
context and receptor availability. We previously reported that Wnt-3a induces
neural differentiation of human embryonic stem cell-derived neural stem cells
(NSCs) in a β-catenin-independent manner by activating a signal involving JNK and
the AP-1 family member ATF-2. Here, we report the results of a gene silencing
approach to identify the Wnt receptors that mediate this response to Wnt-3a.
Silencing of ROR2 increased neuronal differentiation, as measured by expression
of the genes DCX, NEUROD1 and NGN1, suggesting ROR2 signals normally prevent
differentiation. Silencing of the other Wnt receptors singly did not affect Wnt-3ainduced
neuronal differentiation. However, pair-wise silencing of ROR1 and FZD4
or FZD5 and of LRP6 and FZD4 or FZD5 inhibited neuronal differentiation, as
detected by reductions in the expression of neuronal genes and
immunocytochemical detection of DCX and NEUROD1 and DCX. Ectopic expression
of these receptors in HEK 293 cells increased ATF2-dependent transcription. In
addition, ROR1 co-immunoprecipitated with FZD4 and LRP6 in transfected HEK
293 cells and colocalized with FZD4 and with LRP6 at the cell surface of
transfected L cells. Wnt-3a did not appear to affect these interactions but did alter
the interactions between LRP6 and FZD4/5. Together, these observations highlight
roles for ROR1, LRP6, FZD4 and FZD5 in neural stem cell differentiation and
provide support for a model in which dynamic interactions among these receptors
mediate Wnt-3a activation of ATF2 signaling.
Date Issued
2016-10-05
Date Acceptance
2016-09-22
Citation
Molecular Neurobiology, 2016, 54 (8), pp.6213-6224
ISSN
1559-1182
Publisher
Springer
Start Page
6213
End Page
6224
Journal / Book Title
Molecular Neurobiology
Volume
54
Issue
8
Copyright Statement
The final publication is available at Springer via http://dx.doi.org/10.1007/s12035-016-0151-5
Subjects
Neural stem cells
Wnt signaling pathways
1109 Neurosciences
1702 Cognitive Science
Neurology & Neurosurgery
Publication Status
Published