Journal of Alzheimer's Disease
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Home > Amyloid-β Reduces Exosome Release from Astrocytes by Enhancing JNK Phosphorylation.

TitleAmyloid-β Reduces Exosome Release from Astrocytes by Enhancing JNK Phosphorylation.
Publication TypeJournal Article
Year of Publication2016
AuthorsAbdullah, M, Takase, H, Nunome, M, Enomoto, H, Ito, J-I, Gong, J-S, Michikawa, M
JournalJ Alzheimers Dis
Volume53
Issue4
Pagination1433-41
Date Published2016 Jul 02
ISSN1875-8908
Abstract

Exosomes are small extracellular vesicles secreted by variety of cell types such as neurons, astrocytes, and oligodendrocytes. It is suggested that exosomes play essential role in the maintenance of the neuronal functions and also in the clearance of amyloid-β (Aβ) from the brain. Aβ is well known to cause neuronal cell death, whereas little is known about its effect on astrocytes. In this study, we examined the effect of Aβ on release of exosomes from astrocytes in culture. We analyzed release of exosomes and apoE, both of which are known to remove/clear Aβ from the brain, in the culture medium of astrocytes. We found that exosome and apoE-HDL were successfully separated by density gradient ultracentrifugation demonstrated by distribution of their specific markers, flotillin and HSP90, and cholesterol, and morphological analysis using electron microscopy. Exosome release was significantly reduced by Aβ1-42 treatment in cultured astrocytes accompanied by an increased JNK phosphorylation. Whereas, apoE-HDL release remained unchanged. A JNK inhibitor restored the decreased levels of exosome release induced by Aβ treatment to levels similar to those of control, suggesting that Aβ1-42 inhibits exosome release via stimulation of JNK signal pathway. Because exosomes are shown to remove Aβ in the brain, our findings suggest that increased Aβ levels in the brain may impair the exosome-mediated Aβ clearance pathway.

DOI10.3233/JAD-160292
Alternate JournalJ. Alzheimers Dis.
PubMed ID27392863
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Source URL: https://www.j-alz.com/content/amyloid-%CE%B2-reduces-exosome-release%C2%A0%C2%A0astrocytes-enhancing-jnk-phosphorylation