Microglia Do Not Take Up Soluble Amyloid-beta Peptides, But Partially Degrade Them by Secreting Insulin-degrading Enzyme.
Abstract
Microglia play important roles in the pathogenesis of Alzheimer's disease (AD), in part, by affecting the clearance of amyloid-β (Aβ) peptides. Most studies, however, used synthetic soluble Aβ (sAβ) at higher concentrations. The exact mechanisms underlying microglia-mediated clearance of physiological sAβ at very low concentrations remain unclear. Here we reported that there were much more Iba-1- and CD68-positive microglia and significantly less sAβ left in the brain of adult mice 5 days after the surgery of sAβ microinjection compared to 2 h after the surgery (p < 0.05). However, very few Iba-1- and CD68-positive microglia co-localized with microinjected fluorescently labeled sAβ (FLsAβ42) 5 days after the surgery. Also, there was no co-localization of FLsAβ42 with a lysosomal marker (LAMP-1) 5 days after the surgery. There was no significant difference in the percentage of Aβ+/PE-CD11b+/APC-CD45low microglia between the control group and the group microinjected with TBS-soluble Aβ extracted from the brains of AD patients (p > 0.05). The degradation of physiological sAβ was prevented by a highly selective insulin-degrading enzyme inhibitor (Ii1) but not by a phagocytosis inhibitor (polyinosinic acid) or pinocytosis inhibitor ...Continue Reading
References
Amyloid-beta peptide levels in brain are inversely correlated with insulysin activity levels in vivo
Loss of neprilysin function promotes amyloid plaque formation and causes cerebral amyloid angiopathy
Citations
Related Concepts
Related Feeds
Alzheimer's Disease: Amyloid Beta
Alzheimer's disease is a neurodegenerative disease associated with the accumulation of amyloid plaques in the brain; these plaques are comprised of amyloid beta deposits. Here is the latest research in this field.
Alzheimer's Disease: Endosomes
Dysfunctional endosomal trafficking may be associated with Alzheimer’s disease (AD) pathology. Targeting the endosome may advance treatment options for AD. Here is the latest research on endosomes and AD.
Alzheimer's Disease: Microglia
Microglia are a type of glial cell found throughout the brain and spinal cord. Microglia have been found to be associated with Alzheimer's disease development and progression. Here are the latest discoveries pertaining to Alzheimer's disease and microglia.