Among harmful conditions damaging the blood-brain barrier, cerebral stroke and reperfusion injuries were proposed as contributing factors to Alzheimer's disease etiology. Indeed it was reported that ischemic conditions promote beta-amyloid peptide production in brain endothelial cells, although implicated mechanisms are yet not fully understood. Oxidative injury related to ischemia affects membrane-lipids profile by altering their biochemical properties and structural dynamics, which are also believed to play significant role in the amyloid precursor protein processing, suggesting a link between alterations in lipid membrane composition and beta-amyloid peptide production enhancement. Using brain microvascular endothelial cells, here we demonstrate how oxygen and glucose deprivation followed by normal conditions restoration, mimicking ischemic environment, increases cell cholesterol amount (+20%), reduces membrane fluidity and results in strong activation (+40%) of beta-secretase 1 enzymatic activity. Moreover, we observed an increase of amyloid precursor protein and beta-secretase 1 protein levels with altered localization in non-discrete (Triton X-100 soluble) membrane domains, leading to an enhanced production of amyloid precursor protein beta-carboxyl-terminal fragment. Therefore, lipid alterations induced by oxygen and glucose deprivation enhance beta-secretase 1 activity, favor its proximity to amyloid precursor protein and may concur to increased amyloidogenic cleavage. The latter, represents a detrimental event that may contribute to beta-amyloid homeostasis impairment in the brain and to Alzheimer's disease-related BBB dysfunctions.
Ischemic conditions and beta-secretase activation: The impact of membrane cholesterol enrichment as triggering factor in rat brain endothelial cells / A. Brambillaa, E. Lonati, C. Milani, A. Rizzo, F. Farina, L. Botto, M. Masserini, P. Palestini, A. Bulbarelli. - In: THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY & CELL BIOLOGY. - ISSN 1357-2725. - 69(2015), pp. 95-104.
|Titolo:||Ischemic conditions and beta-secretase activation: The impact of membrane cholesterol enrichment as triggering factor in rat brain endothelial cells|
|Parole Chiave:||Alzheimer's disease; (AD); Brain endothelial cells; Oxygen glucose deprivation (OGD); BACE1 activity; Amyloid precursor protein (APP); Cholesterol|
|Settore Scientifico Disciplinare:||Settore BIO/10 - Biochimica|
|Data di pubblicazione:||2015|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.biocel.2015.10.005|
|Appare nelle tipologie:||01 - Articolo su periodico|