Nord LC, Sundqvist J, Andersson E, Fried G
Neurodegener Dis 7 (6) 349-364 [2010-06-04; online 2010-06-04]
A key event in Alzheimer's disease pathology is the proteolytic processing of amyloid precursor protein (APP), whereby β-amyloid (Aβ) peptide is produced. Oestrogen is acknowledged to influence cognitive function and has been shown to regulate the secretory metabolism of APP and decrease the production of Aβ, thereby protecting the brain from neurodegeneration. The mechanism for this effect is unknown. To investigate possible oestrogen regulation of the expression of the APP processing enzymes at the gene and/or protein level. The effects of oestrogen on gene and protein expression of α- (TACE and ADAM10), β- (BACE) and γ- (presenilin 1) secretases in cultured human fetal neurons and glial cells were studied. The RNase protection assay, gene expression microarray analysis and relative quantitative real-time PCR were used to analyse gene expression, while the protein expression and cellular localization of the secretases were studied by immunoblot and confocal microscopy. Oestrogen is involved in the regulation of the gene expression of TACE and presenilin 1. Most importantly, BACE protein expression was downregulated by oestrogen treatment in mixed neuronal/glial cell cultures. Our results also show the cellular localization of the secretases in human neurons and glial cells, which has been thoroughly discussed in the light of the localization of APP processing. Our results indicate that oestrogen may affect APP processing directly by regulating the expression of the involved enzymes.
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