Secreted Amyloid Precursor Protein-Alpha Promotes Arc Protein Synthesis in Hippocampal Neurons.

ABSTRACT: Secreted amyloid precursor protein-? (sAPP?) is a neuroprotective and memory-enhancing molecule, however, the mechanisms through which sAPP? promotes these effects are not well understood. Recently, we have shown that sAPP? enhances cell-surface expression of glutamate receptors. Activity-related cytoskeletal-associated protein Arc (Arg3.1) is an immediate early gene capable of modulating long-term potentiation, long-term depression and homeostatic plasticity through regulation of ?-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor localization. Accordingly, we hypothesized that sAPP? may enhance synaptic plasticity, in part, by the de novo synthesis of Arc. Using primary cortical and hippocampal neuronal cultures we found that sAPP? (1 nM, 2 h) enhances levels of Arc mRNA and protein. Arc protein levels were increased in both the neuronal somata and dendrites in a Ca2+/calmodulin-dependent protein kinase II-dependent manner. Additionally, dendritic Arc expression was dependent upon activation of mitogen-activated protein kinase and protein kinase G. The enhancement of dendritic Arc protein was significantly reduced by antagonism of N-methyl-D-aspartate (NMDA) and nicotinic acetylcholine (?7nACh) receptors, and fully eliminated by dual application of these antagonists. This effect was further corroborated in area CA1 of acute hippocampal slices. These data suggest sAPP?-regulated plasticity within hippocampal neurons is mediated by cooperation of NMDA and ?7nACh receptors to engage a cascade of signal transduction molecules to enhance the transcription and translation of Arc.

SUBMITTER: Livingstone RW 

PROVIDER: S-EPMC6702288 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature