title: HES5 is a key mediator of Wnt-3a-induced neuronal differentiation.
abstract: Human neural stem/progenitor cell (hNPC)-derived neuronal progeny has been suggested as a promising cell source in a variety of neurodegenerative diseases. Understanding the underlying mechanisms that regulate neuronal differentiation is essential for efficient cell-based therapies. Wnt and Notch signaling has been shown to be crucial in this process. However, their interactions in the process of neuronal differentiation remain elusive. By using human fetal (ReNcell VM) and iPS-derived hNPCs we demonstrate that Wnt-3a immediately induced a transient HES1 upregulation and a sustained HES5 repression that was accompanied by upregulation of the proneural gene MASH1. Conversely, overexpression of HES5 resulted in reduced MASH1 expression. Remarkably, HES5 overexpression efficiently blocked Wnt-3a as well as γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT)-induced neuronal differentiation that was accompanied by a strong MASH1 downregulation thus directly linking HES5 repression/MASH1 induction to the proneurogenic effect of Wnt-3a. Stabilized β-catenin or treatment with the specific glycogen synthase kinase 3 beta (GSK3β) inhibitor SB-216763 failed to or only partially mimicked these effects, suggesting a GSK3β- and β-catenin-independent mechanism. Further, inhibition of Wnt-3a-LDL-receptor-related protein 5/6 (LRP5/6) interactions using Dickkopf-1 (Dkk-1) failed to inhibit the modulatory effect of Wnt-3a on HES1/5 and neuronal differentiation. Taken together, these data identify HES5 as a key mediator of the Wnt-3a proneurogenic effect occurring independently of the classical Wnt/β-catenin signaling cascade thus further deciphering crosstalk mechanisms of Wnt and Notch signaling pathways regulating cell fate of hNPCs.
authors.affiliation: Albrecht-Kossel-Institute for Neuroregeneration (AKos), University of Rostock , Rostock, Germany .
authors.forename: Carolin
authors.initials: C
authors.lastname: Mußmann
authors.forename: Rayk
authors.initials: R
authors.lastname: Hübner
authors.forename: Michaela
authors.initials: M
authors.lastname: Trilck
authors.forename: Arndt
authors.initials: A
authors.lastname: Rolfs
authors.forename: Moritz J
authors.initials: MJ
authors.lastname: Frech
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007211:Indoles / Q000008:administration & dosage; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D008301:Maleimides / Q000008:administration & dosage; D058953:Neural Stem Cells / Q000187:drug effects; D055495:Neurogenesis; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D060449:Wnt Signaling Pathway / Q000235:genetics; D060509:Wnt3A Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D007211:Indoles; D008301:Maleimides; D051880:Receptors, Notch; D012097:Repressor Proteins; D060509:Wnt3A Protein; C417521:SB 216763; C077478:HES5 protein, human