Background: Exosomes, small extracellular vesicles of endosomal origin, have been suggested to be involved in both the metabolism and aggregation of Alzheimer's disease (AD)-associated amyloid β-protein (Aβ). Despite their ubiquitous presence and the inclusion of components which can potentially interact with Aβ, the role of exosomes in regulating synaptic dysfunction induced by Aβ has not been explored.
Results: We here provide in vivo evidence that exosomes derived from N2a cells or human cerebrospinal fluid can abrogate the synaptic-plasticity-disrupting activity of both synthetic and AD brain-derived Aβ. Mechanistically, this effect involves sequestration of synaptotoxic Aβ assemblies by exosomal surface proteins such as PrPC rather than Aβ proteolysis.
Conclusions: These data suggest that exosomes can counteract the inhibitory action of Aβ, which contributes to perpetual capability for synaptic plasticity.
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http://dx.doi.org/10.1186/1756-6606-6-47 | DOI Listing |
Philos Trans R Soc Lond B Biol Sci
January 2014
Department of Pharmacology and Therapeutics, Institute of Neuroscience, Trinity College, , Biotechnology Building, Dublin 2, Republic of Ireland.
Many endogenous factors influence the time course and extent of the detrimental effects of amyloid β-protein (Aβ) on synaptic function. Here, we assessed the impact of varying endogenous glutamatergic and cholinergic transmission by pharmacological means on the disruption of plasticity at hippocampal CA3-to-CA1 synapses in the anaesthetized rat. NMDA receptors (NMDARs) are considered critical in mediating Aβ-induced inhibition of long-term potentiation (LTP).
View Article and Find Full Text PDFMol Brain
November 2013
Department of Life Sciences, Pohang University of Science and Technology (POSTECH), Pohang, Gyungbuk 790-784, Korea.
Background: Exosomes, small extracellular vesicles of endosomal origin, have been suggested to be involved in both the metabolism and aggregation of Alzheimer's disease (AD)-associated amyloid β-protein (Aβ). Despite their ubiquitous presence and the inclusion of components which can potentially interact with Aβ, the role of exosomes in regulating synaptic dysfunction induced by Aβ has not been explored.
Results: We here provide in vivo evidence that exosomes derived from N2a cells or human cerebrospinal fluid can abrogate the synaptic-plasticity-disrupting activity of both synthetic and AD brain-derived Aβ.
Neuromolecular Med
March 2010
Department of Pharmacology and Therapeutics, Biotechnology Building and Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
Alzheimer's disease (AD) is characterized neuropathologically by the deposition of different forms of amyloid beta-protein (A beta) including variable amounts of soluble species that correlate with severity of dementia. The extent of synaptic loss in the brain provides the best morphological correlate of cognitive impairment in clinical AD. Animal research on the pathophysiology of AD has therefore focussed on how soluble A beta disrupts synaptic mechanisms in vulnerable brain regions such as the hippocampus.
View Article and Find Full Text PDFBiochem Soc Trans
November 2007
Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
There is growing evidence that mild cognitive impairment in early AD (Alzheimer's disease) may be due to synaptic dysfunction caused by the accumulation of non-fibrillar, oligomeric Abeta (amyloid beta-peptide), long before widespread synaptic loss and neurodegeneration occurs. Soluble Abeta oligomers can rapidly disrupt synaptic memory mechanisms at extremely low concentrations via stress-activated kinases and oxidative/nitrosative stress mediators. Here, we summarize experiments that investigated whether certain putative receptors for Abeta, the alphav integrin extracellular cell matrix-binding protein and the cytokine TNFalpha (tumour necrosis factor alpha) type-1 death receptor mediate Abeta oligomer-induced inhibition of LTP (long-term potentiation).
View Article and Find Full Text PDFBiochem Soc Trans
August 2005
Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland.
AD (Alzheimer's disease) is characterized by a progressive and devastating mental decline that is usually presaged by impairment of a form of memory dependent on medial temporal lobe structures, including the hippocampus. The severity of clinical dementia correlates positively with the cerebral load of the AD-related protein Abeta (amyloid beta), particularly in its soluble form rather than the insoluble fibrillar Abeta found in amyloid plaques. Recent research in animal models of AD has pointed to a potentially important role for rapid disruptive effects of soluble species of Abeta on neural function in causing a relatively selective impairment of memory early in the disease.
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