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Cleavage of the vesicular glutamate transporters under excitotoxic conditions

Lobo, Andrea C.; Gomes, Joao R.; Catarino, Tatiana; Mele, Miranda; Fernandez, Pedro; Inacio, Ana LU ; Bahr, Ben A.; Santos, Armanda E.; Wieloch, Tadeusz LU and Carvalho, Ana Luisa, et al. (2011) In Neurobiology of Disease 44(3). p.292-303
Abstract
Glutamate is loaded into synaptic vesicles by vesicular glutamate transporters (VGLUTs), and alterations in the transporters expression directly regulate neurotransmitter release. We investigated changes in VGLUT1 and VGLUT2 protein levels after ischemic and excitotoxic insults. The results show that VGLUT2 is cleaved by calpains after excitotoxic stimulation of hippocampal neurons with glutamate, whereas VGLUT1 is downregulated to a lower extent VGLUT2 was also cleaved by calpains after oxygen/glucose deprivation (OGD), and downregulated after middle cerebral artery occlusion (MCAO) and intrahippocampal injection of kainate. In contrast, VGLUT1 was not affected after OGD. Incubation of isolated synaptic vesicles with recombinant calpain... (More)
Glutamate is loaded into synaptic vesicles by vesicular glutamate transporters (VGLUTs), and alterations in the transporters expression directly regulate neurotransmitter release. We investigated changes in VGLUT1 and VGLUT2 protein levels after ischemic and excitotoxic insults. The results show that VGLUT2 is cleaved by calpains after excitotoxic stimulation of hippocampal neurons with glutamate, whereas VGLUT1 is downregulated to a lower extent VGLUT2 was also cleaved by calpains after oxygen/glucose deprivation (OGD), and downregulated after middle cerebral artery occlusion (MCAO) and intrahippocampal injection of kainate. In contrast, VGLUT1 was not affected after OGD. Incubation of isolated synaptic vesicles with recombinant calpain also induced VGLUT2 cleavage, with a little effect observed for VGLUT1. N-terminal sequencing analysis showed that calpain cleaves VGLUT2 in the C-terminus, at Asn(534) and Lys(542). The truncated GFP-VGWT2 forms were found to a great extent in non-synaptic regions along neurites, when compared to GFP-VGLUT2. These findings show that excitotoxic and ischemic insults downregulate VGLUT2, which is likely to affect glutamatergic transmission and cell death, especially in the neonatal period when the transporter is expressed at higher levels. (C) 2011 Elsevier Inc. All rights reserved. (Less)
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published
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keywords
Brain ischemia, Calpains, Excitotoxicity, Oxygen and glucose, deprivation, Vesicular glutamate transporters
in
Neurobiology of Disease
volume
44
issue
3
pages
292 - 303
publisher
Elsevier
external identifiers
  • wos:000295816200005
  • scopus:80053269066
ISSN
0969-9961
DOI
10.1016/j.nbd.2011.07.010
language
English
LU publication?
yes
id
5bc69dc7-bedb-453d-bf58-1cfad689d6ce (old id 2212292)
date added to LUP
2011-12-01 08:32:12
date last changed
2017-07-30 03:06:34
@article{5bc69dc7-bedb-453d-bf58-1cfad689d6ce,
  abstract     = {Glutamate is loaded into synaptic vesicles by vesicular glutamate transporters (VGLUTs), and alterations in the transporters expression directly regulate neurotransmitter release. We investigated changes in VGLUT1 and VGLUT2 protein levels after ischemic and excitotoxic insults. The results show that VGLUT2 is cleaved by calpains after excitotoxic stimulation of hippocampal neurons with glutamate, whereas VGLUT1 is downregulated to a lower extent VGLUT2 was also cleaved by calpains after oxygen/glucose deprivation (OGD), and downregulated after middle cerebral artery occlusion (MCAO) and intrahippocampal injection of kainate. In contrast, VGLUT1 was not affected after OGD. Incubation of isolated synaptic vesicles with recombinant calpain also induced VGLUT2 cleavage, with a little effect observed for VGLUT1. N-terminal sequencing analysis showed that calpain cleaves VGLUT2 in the C-terminus, at Asn(534) and Lys(542). The truncated GFP-VGWT2 forms were found to a great extent in non-synaptic regions along neurites, when compared to GFP-VGLUT2. These findings show that excitotoxic and ischemic insults downregulate VGLUT2, which is likely to affect glutamatergic transmission and cell death, especially in the neonatal period when the transporter is expressed at higher levels. (C) 2011 Elsevier Inc. All rights reserved.},
  author       = {Lobo, Andrea C. and Gomes, Joao R. and Catarino, Tatiana and Mele, Miranda and Fernandez, Pedro and Inacio, Ana and Bahr, Ben A. and Santos, Armanda E. and Wieloch, Tadeusz and Carvalho, Ana Luisa and Duarte, Carlos B.},
  issn         = {0969-9961},
  keyword      = {Brain ischemia,Calpains,Excitotoxicity,Oxygen and glucose,deprivation,Vesicular glutamate transporters},
  language     = {eng},
  number       = {3},
  pages        = {292--303},
  publisher    = {Elsevier},
  series       = {Neurobiology of Disease},
  title        = {Cleavage of the vesicular glutamate transporters under excitotoxic conditions},
  url          = {http://dx.doi.org/10.1016/j.nbd.2011.07.010},
  volume       = {44},
  year         = {2011},
}