Ojo, Bunmi; Rezaie, Payam; Gabbott, Paul; Davies, Heather; Colyer, Frances; Cowley, Thelma R.; Lynch, Marina and Stewart, Michael
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|DOI (Digital Object Identifier) Link:||http://dx.doi.org/doi:10.1016/j.bbi.2011.09.013|
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Altered synaptic morphology, progressive loss of synapses and glial (astrocyte and microglial) cell activation are considered as characteristic hallmarks of ageing. Recent evidence suggests that there is a concomitant age-related decrease in expression of the presynaptic protein, synaptophysin, and the neuronal glycoprotein CD200, which, by interacting with its receptor, plays a role in maintaining microglia in a quiescent state. These age-related changes may be indicative of reduced neuroglial support of synapses. FG Loop (FGL) peptide synthesised from the second fibronectin type III module of neural cell adhesion molecule (NCAM), has previously been shown to attenuate age-related glial cell activation, and to ‘restore’ cognitive function in aged rats. The mechanisms by which FGL exerts these neuroprotective effects remain unclear, but could involve regulation of CD200, modifying glial-synaptic interactions (affecting neuroglial ‘support’ at synapses), or impacting directly on synaptic function. Light and electron microscopic (EM) analyses were undertaken to investigate whether systemic treatment with FGL (i) alters CD200, synaptophysin (presynaptic) and PSD95 (postsynaptic) immunohistochemical expression levels, (ii) affects synaptic number, or (iii) exerts any effects on glial-synaptic interactions within young (4 monthold) and aged (22 month-old) rat hippocampus. Treatment with FGL attenuated the age-related loss of synaptophysin immunoreactivity (-ir) within CA3 and hilus (with no major effect on PSD-95-ir), and of CD200-ir specifically in the CA3 region. Ultrastructural morphometric analyses showed that FGL treatment (i) prevented age-related loss in astrocyte-synaptic contacts, (ii) reduced microgliasynaptic contacts in the CA3 stratum radiatum, but (iii) had no effect on the mean number of synapses in this region. These data suggest that FGL mediates its neuroprotective effects by regulating glial-synaptic interaction.
|Item Type:||Journal Article|
|Copyright Holders:||2011 Elsevier Inc.|
|Keywords:||immunoelectron microscopy; aging; hippocampus; CA3; astrocytes; microglia; CD200; synaptophysin; PSD-95; morphometric analysis|
|Academic Unit/Department:||Science > Life, Health and Chemical Sciences
|Depositing User:||Michael Stewart|
|Date Deposited:||02 Nov 2011 14:14|
|Last Modified:||27 Nov 2012 15:56|
Available Versions of this Item
Age-related changes in the hippocampus (loss of synaptophysin and glial-synaptic interaction) are modified by systemic treatment with an NCAM-derived peptide, FGL. (deposited 06 Oct 2011 15:30)
- Age-related changes in the hippocampus (loss of synaptophysin and glial-synaptic interaction) are modified by systemic treatment with an NCAM-derived peptide, FGL. (deposited 02 Nov 2011 14:14) [Currently Displayed]
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