TY - JOUR

T1 - N-Terminomic Changes in Neurons During Excitotoxicity Reveal Proteolytic Events Associated With Synaptic Dysfunctions and Potential Targets for Neuroprotection

AU - Ameen, S. Sadia

AU - Griem-Krey, Nane

AU - Dufour, Antoine

AU - Hossain, M. Iqbal

AU - Hoque, Ashfaqul

AU - Sturgeon, Sharelle

AU - Nandurkar, Harshal

AU - Draxler, Dominik F.

AU - Medcalf, Robert L.

AU - Kamaruddin, Mohd Aizuddin

AU - Lucet, Isabelle S.

AU - Leeming, Michael G.

AU - Liu, Dazhi

AU - Dhillon, Amardeep

AU - Lim, Jet Phey

AU - Basheer, Faiza

AU - Zhu, Hong Jian

AU - Bokhari, Laita

AU - Roulston, Carli L.

AU - Paradkar, Prasad N.

AU - Kleifeld, Oded

AU - Clarkson, Andrew N.

AU - Wellendorph, Petrine

AU - Ciccotosto, Giuseppe D.

AU - Williamson, Nicholas A.

AU - Ang, Ching Seng

AU - Cheng, Heung Chin

N1 - Publisher Copyright: Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.

PY - 2023

Y1 - 2023

N2 - Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death. We found that most proteolytically processed proteins in excitotoxic neurons are likely substrates of calpains, including key synaptic regulatory proteins such as CRMP2, doublecortin-like kinase I, Src tyrosine kinase and calmodulin-dependent protein kinase IIβ (CaMKIIβ). Critically, calpain-catalyzed proteolytic processing of these proteins generates stable truncated fragments with altered activities that potentially contribute to neuronal death by perturbing synaptic organization and function. Blocking calpain-mediated proteolysis of one of these proteins, Src, protected against neuronal loss in a rat model of neurotoxicity. Extrapolation of our N-terminomic results led to the discovery that CaMKIIα, an isoform of CaMKIIβ, undergoes differential processing in mouse brains under physiological conditions and during ischemic stroke. In summary, by identifying the neuronal proteins undergoing proteolysis during excitotoxicity, our findings offer new insights into excitotoxic neuronal death mechanisms and reveal potential neuroprotective targets for neurological disorders.

AB - Excitotoxicity, a neuronal death process in neurological disorders such as stroke, is initiated by the overstimulation of ionotropic glutamate receptors. Although dysregulation of proteolytic signaling networks is critical for excitotoxicity, the identity of affected proteins and mechanisms by which they induce neuronal cell death remain unclear. To address this, we used quantitative N-terminomics to identify proteins modified by proteolysis in neurons undergoing excitotoxic cell death. We found that most proteolytically processed proteins in excitotoxic neurons are likely substrates of calpains, including key synaptic regulatory proteins such as CRMP2, doublecortin-like kinase I, Src tyrosine kinase and calmodulin-dependent protein kinase IIβ (CaMKIIβ). Critically, calpain-catalyzed proteolytic processing of these proteins generates stable truncated fragments with altered activities that potentially contribute to neuronal death by perturbing synaptic organization and function. Blocking calpain-mediated proteolysis of one of these proteins, Src, protected against neuronal loss in a rat model of neurotoxicity. Extrapolation of our N-terminomic results led to the discovery that CaMKIIα, an isoform of CaMKIIβ, undergoes differential processing in mouse brains under physiological conditions and during ischemic stroke. In summary, by identifying the neuronal proteins undergoing proteolysis during excitotoxicity, our findings offer new insights into excitotoxic neuronal death mechanisms and reveal potential neuroprotective targets for neurological disorders.

KW - calpains

KW - CaM kinase IIa

KW - CaM kinase IIb

KW - CRMP2

KW - excitotoxicity

KW - neuronal death

KW - neuroprotection

KW - proteolytic processing

KW - Src

KW - synaptic damage

U2 - 10.1016/j.mcpro.2023.100543

DO - 10.1016/j.mcpro.2023.100543

M3 - Journal article

C2 - 37030595

AN - SCOPUS:85160199666

VL - 22

JO - Molecular and Cellular Proteomics

JF - Molecular and Cellular Proteomics

SN - 1535-9476

IS - 5

M1 - 100543

ER -