Chronic Cerebral Hypoperfusion Induced Synaptic Proteome Changes in the rat Cerebral Cortex
Chronic cerebral hypoperfusion (CCH) evokes mild cognitive impairment (MCI) and contributes to the progression of vascular dementia and Alzheimer’s disease (AD). How CCH induces these neurodegenerative processes that may spread along the synaptic network and whether they are detectable at the synaptic proteome level of the cerebral cortex remains to be established. In the present study, we report the synaptic protein changes in the cerebral cortex after stepwise bilateral common carotid artery occlusion (BCCAO) induced CCH in the rat. The occlusions were confirmed with magnetic resonance angiography 5 weeks after the surgery. Synaptosome fractions were prepared using sucrose gradient centrifugation from cerebral cortex dissected 7 weeks after the occlusion. The synaptic protein differences between the sham operated and CCH groups were analyzed with label-free nanoUHPLC-MS/MS. We identified 46 proteins showing altered abundance due to CCH. In particular, synaptic protein and lipid metabolism, as well as GABA shunt-related proteins showed increased while neurotransmission and synaptic assembly-related proteins showed decreased protein level changes in CCH rats. Protein network analysis of CCH-induced protein alterations suggested the importance of increased synaptic apolipoprotein E (APOE) level as a consequence of CCH. Therefore, the change in APOE level was confirmed with Western blotting. The identified synaptic protein changes would precede the onset of dementia-like symptoms in the CCH model, suggesting their importance in the development of vascular dementia.
KeywordsChronic cerebral hypoperfusion Vascular dementia Alzheimer’s disease Synaptic proteome Label-free LC-MS/MS GABAergic synapse Apolipoprotein E
Bilateral common carotid artery occlusion
Chronic cerebral hypoperfusion
This study was supported by Gedeon Richter Plc, the Hungarian National Research, Development and Innovation Office (KMOP-1.1.5-08-2009-0001, KTIA_NAP_13-1-2013-0001, KTIA_NAP_B_13-2-2014-0004 and KTIA_NAP_13-2-2015-0003 programs). The founders had no role in the study design; in the collection, analysis and interpretation of data; in writing of the manuscript; and in the decision to submit the article for publication. We would like to thank Dr. Gábor Juhász for helpful discussions on the research plan.
Compliance with Ethical Guidelines
The care and experimentation of all animals conformed to the Hungarian Act of Animal Care and Experimentation (1998, XXVIII) and to the guidelines of the European Communities Council Directive, 86/609/EEC as well as with local regulations for the care and use of animals for research.
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