Elsevier

Neuroscience

Volume 463, 21 May 2021, Pages 317-336
Neuroscience

Research Article
SCO-spondin-derived Peptide Protects Neurons from Glutamate-induced Excitotoxicity

https://doi.org/10.1016/j.neuroscience.2021.02.005Get rights and content
Under a Creative Commons license
open access

Highlights

  • SCO-spondin-derived NX peptide protects rat neurons against glutamate toxicity.

  • NX210 and NX210c disrupt the apoptotic cascade and activate the PI3K/mTOR pathway.

  • Integrins are putative receptors for NX210 and NX210c.

  • NX210c reduces apoptosis and necrosis in human primary cortical neurons.

Abstract

Subcommissural organ (SCO)-spondin is a brain-specific glycoprotein produced during embryogenesis, that strongly contributes to neuronal development. The SCO becomes atrophic in adults, halting SCO-spondin production and its neuroprotective functions. Using rat and human neuronal cultures, we evaluated the neuroprotective effect of an innovative peptide derived from SCO-spondin against glutamate excitotoxicity. Primary neurons were exposed to glutamate and treated with the linear (NX210) and cyclic (NX210c) forms of the peptide. Neuronal survival and neurite networks were assessed using immunohistochemistry or biochemistry. The mechanism of action of both peptide forms was investigated by exposing neurons to inhibitors targeting receptors and intracellular mediators that trigger apoptosis, neuronal survival, or neurite growth. NX210c promoted neuronal survival and prevented neurite network retraction in rat cortical and hippocampal neurons, whereas NX210 was efficient only in neuronal survival (cortical neurons) or neurite networks (hippocampal neurons). They triggered neuroprotection via integrin receptors and γ-secretase substrate(s), activation of the PI3K/mTOR pathway and disruption of the apoptotic cascade. The neuroprotective effect of NX210c was confirmed in human cortical neurons via the reduction of lactate dehydrogenase release and recovery of normal basal levels of apoptotic cells. Together, these results show that NX210 and NX210c protect against glutamate neurotoxicity through common and distinct mechanisms of action and that, most often, NX210c is more efficient than NX210. Proof of concept in central nervous system animal models are under investigation to evaluate the neuroprotective action of SCO-spondin-derived peptide.

Abbreviations

amyloid β
AIF1
apoptosis-inducing factor 1
Akt
protein kinase B
ANOVA
analysis of variance
APP
amyloid precursor protein
Bax
B-cell lymphoma 2-associated X
Bcl-2
B-cell lymphoma 2
BDNF
brain-derived neurotrophic factor
BSA
bovine albumin serum
Cyt c
cytochrome c
dpi
days post-injury
div
days in vitro
DNA
deoxyribonucleic acid
ECM
extracellular matrix
FCS
fetal calf serum
FTS
farnesylthiosalicyclic acid
glu
glutamate
GMP
good manufacturing practices
LDH
lactate dehydrogenase
KW
Kruskal–Wallis
l-NAME
l-NG-nitroarginine methyl ester
MAPK
mitogen-activated protein kinase
MAP-2
microtubule associated protein-2
MEK
mitogen-activated protein/extracellular signal-regulated kinase kinase
mTOR
mammalian target of rapamycin
NADH
nicotinamide adenine dinucleotide hydrogen
NCID
Notch intracellular domain
NFκB
nuclear factor-kappa B
NOS
nitric oxide synthase
NMdA
N-methyl-d-aspartate
PBS
phosphate buffered saline
PI3K
phosphoinositide 3-kinase
PS
penicillin/streptomycin
p70S6K
ribosomal protein S6 kinase
Ras
rat sarcoma
RT
room temperature
SCO
subcommissural organ
SEM
standard error of the mean
TrkB
tropomyosin receptor kinase B
TSR
thrombospondin repeat
Tuj1
neuron-specific class III beta-tubulin

Key words

NX210
NX210c
β1-integrin
γ-secretase
PI3K/mTOR
Bcl-2

Cited by (0)

These authors contributed equally to this work.