A novel non-canonical Notch signaling regulates expression of synaptic vesicle proteins in excitatory neurons.

Yukari Hayashi,Raphael Kopan,Katsuto Hozumi,Yumiko Saga,Michisuke Yuzaki,Akihiro Harada,Taisuke Tomita,Takeshi Iwatsubo,Hiroshi Nishimune

doi:10.1038/srep23969

Abstract

Notch signaling plays crucial roles for cellular differentiation during development through γ-secretase-dependent intramembrane proteolysis followed by transcription of target genes. Although recent studies implicate that Notch regulates synaptic plasticity or cognitive performance, the molecular mechanism how Notch works in mature neurons remains uncertain. Here we demonstrate that a novel Notch signaling is involved in expression of synaptic proteins in postmitotic neurons. Levels of several synaptic vesicle proteins including synaptophysin 1 and VGLUT1 were increased when neurons were cocultured with Notch ligands-expressing NIH3T3 cells. Neuron-specific deletion of Notch genes decreased these proteins, suggesting that Notch signaling maintains the expression of synaptic vesicle proteins in a cell-autonomous manner. Unexpectedly, cGMP-dependent protein kinase (PKG) inhibitor, but not γ-secretase inhibitor, abolished the elevation of synaptic vesicle proteins, suggesting that generation of Notch intracellular domain is dispensable for this function. These data uncover a ligand-dependent, but γ-secretase-independent, non-canonical Notch signaling involved in presynaptic protein expression in postmitotic neurons.

Highlights

Notch signaling plays crucial roles for cellular differentiation during development through γ-secretasedependent intramembrane proteolysis followed by transcription of target genes
We found that activation of the endogenous Notch receptor with the DSL ligands in cultured neurons increased the expression levels of several synaptic vesicle proteins such as synaptophysin 1 and vesicular glutamate transporter 1 (VGLUT1)
Venus immunoreactivity was predominantly observed in the subventricular zone and the hippocampal dentate gyrus of neonatal Notch1-Venus knock-in (N1V-KI) mouse brain, which was not detected in wild type tissue (Fig. 1b)

Summary

Introduction

Notch signaling plays crucial roles for cellular differentiation during development through γ-secretasedependent intramembrane proteolysis followed by transcription of target genes. CGMP-dependent protein kinase (PKG) inhibitor, but not γ-secretase inhibitor, abolished the elevation of synaptic vesicle proteins, suggesting that generation of Notch intracellular domain is dispensable for this function. These data uncover a liganddependent, but γ-secretase-independent, non-canonical Notch signaling involved in presynaptic protein expression in postmitotic neurons. We found that activation of the endogenous Notch receptor with the DSL ligands in cultured neurons increased the expression levels of several synaptic vesicle proteins such as synaptophysin 1 and VGLUT1. Γ -secretase activity is not required for the DSL ligand-dependent increment of synaptic vesicle proteins, suggesting that the canonical Notch signaling is not involved in these effects. Our findings indicate that a novel, non-canonical Notch signaling may contribute to the synaptic formation or function in neurons

Objectives

Methods

Results

Conclusion