Enhanced Aβ1–40 Production in Endothelial Cells Stimulated with Fibrillar Aβ1–42

Oregon Health & Science University, United States of America
PLoS ONE (Impact Factor: 3.23). 03/2013; 8(3):e58194. DOI: 10.1371/journal.pone.0058194
Source: PubMed


Amyloid accumulation in the brain of Alzheimer's patients results from altered processing of the 39- to 43-amino acid amyloid β protein (Aβ). The mechanisms for the elevated amyloid (Aβ1-42) are considered to be over-expression of the amyloid precursor protein (APP), enhanced cleavage of APP to Aβ, and decreased clearance of Aβ from the central nervous system (CNS). We report herein studies of Aβ stimulated effects on endothelial cells. We observe an interesting and as yet unprecedented feedback effect involving Aβ1-42 fibril-induced synthesis of APP by Western blot analysis in the endothelial cell line Hep-1. We further observe an increase in the expression of Aβ1-40 by flow cytometry and fluorescence microscopy. This phenomenon is reproducible for cultures grown both in the presence and absence of serum. In the former case, flow cytometry reveals that Aβ1-40 accumulation is less pronounced than under serum-free conditions. Immunofluorescence staining further corroborates these observations. Cellular responses to fibrillar Aβ1-42 treatment involving eNOS upregulation and increased autophagy are also reported.

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    • "Endothelial cells play an important role in BBB function; BBB dysfunction is recognized to participate in neurodegenerative disorders [11], [12]. Cerebral vascular endothelial cells develop highly selective barrier which controls the exchanges between blood and brain compartments for the maintenance and regulation of the neuronal microenvironment [13]. "
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    PLoS ONE 12/2013; 8(12):e82604. DOI:10.1371/journal.pone.0082604 · 3.23 Impact Factor
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    • "Notably, while A␤40 accounts for approximately 90% of secreted A␤ and is the most abundant species recovered from cerebrospinal fluid, it is A␤42 that is the predominant insoluble amyloid isoform deposited in the brain (Iwatsubo et al., 1994). Molecular mechanisms that regulate total A␤ production or the relative proportions of the A␤ isoforms deposited in AD brains (Rajadas et al., 2013), are not well characterized. Our ELISA quantitation of A␤40 and A␤42 products in conditioned media (see Fig. 2B) revealed the 7:1 ratio of A␤40:A␤42 peptides produced by M17 cells is similar to the 10:1 ratio found in the CSF of non-familial AD patients (Seubert et al., 1992), and suggests the M17 in vitro system provides an approach to investigate the regulation of the A␤ intramembrane cleavage site selection. "
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