Analysis of oestrogen regulation of alpha-, beta- and gamma-secretase gene and protein expression in cultured human neuronal and glial cells.
BACKGROUND
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.


OBJECTIVE
To investigate possible oestrogen regulation of the expression of the APP processing enzymes at the gene and/or protein level.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Our results indicate that oestrogen may affect APP processing directly by regulating the expression of the involved enzymes.
Nord
Linda Csöregh
LC
Division of Obstetrics and Gynaecology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden. Linda.AC.Nord@gmail.com
Sundqvist
Johanna
J
Andersson
Eva
E
Fried
Gabriel
G
D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072197:ADAM10 Protein; D000072198:ADAM17 Protein; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics* / Q000378:metabolism*; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism; D001921:Brain / Q000166:cytology; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005333:Fetus; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000187:drug effects*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014404:Tubulin / Q000378:metabolism
D004967:Estrogens; D005904:Glial Fibrillary Acidic Protein; D008565:Membrane Proteins; C508853:PSEN1 protein, human; D053764:Presenilin-1; D012333:RNA, Messenger; D014404:Tubulin; D004958:Estradiol; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human; D051722:ADAM Proteins; D000072197:ADAM10 Protein; C491236:ADAM10 protein, human; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human