Article

CD40 promotion of amyloid beta production occurs via the NF-kappaB pathway.

The Roskamp Institute, Sarasota, FL 34243, USA.
European Journal of Neuroscience (impact factor: 3.63). 04/2007; 25(6):1685-95. DOI:10.1111/j.1460-9568.2007.05424.x pp.1685-95
Source: PubMed

ABSTRACT The CD40 receptor is a member of the tumor necrosis factor (TNF) super-family of trans-membrane receptors. Interaction of CD40 with its ligand CD40L mediates a broad range of immune and inflammatory responses in the periphery and in the central nervous system. Recently it has been suggested that CD40/CD40L interaction is involved in amyloid precursor protein (APP) processing and Alzheimer's disease (AD)-like pathology in transgenic mouse models of AD. We have previously shown that pharmacologically inhibiting CD40/CD40L interaction improves memory deficits in the PSAPP AD mouse model. We have also recently shown that CD40 deficiency mitigates amyloid deposition in APPsw and PSAPP mouse models. In the present report, using human embryonic kidney cells (HEK293) over-expressing both the APPsw mutation and CD40, we demonstrate that CD40/CD40L interaction directly increases the production of APP metabolites (Abeta 1-40, Abeta 1-42, CTFs, sAPPbeta and sAPPalpha). The results also show that CD40/CD40L interaction affects APP processing via the NF-kappaB pathway. Using NFkappaB inhibitors and SiRNAs to silence diverse elements of the NFkappaB pathway, we observe a reduction in levels of both Abeta 1-40 and Abeta 1-42. Taken together, our results further suggest that CD40L stimulation may be a key component in AD pathology and that elements of the NF-kappaB pathway may be suitable targets for therapeutic approaches against AD.

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    Article: Nuclear factor-κB regulates βAPP and β- and γ-secretases differently at physiological and supraphysiological Aβ concentrations.
    Linda Chami, Virginie Buggia-Prévot, Eric Duplan, Dolores Delprete, Mounia Chami, Jean-François Peyron, Frédéric Checler
    [show abstract] [hide abstract]
    ABSTRACT: Anatomical lesions in Alzheimer disease-affected brains mainly consist of senile plaques, inflammation stigmata, and oxidative stress. The nuclear factor-κB (NF-κB) is a stress-activated transcription factor that is activated around senile plaques. We have assessed whether NF-κB could be differentially regulated at physiological or supraphysiological levels of amyloid β (Aβ) peptides. Under these experimental conditions, we delineated the putative NF-κB-dependent modulation of all cellular participants in Aβ production, namely its precursor βAPP (β-amyloid precursor protein) and the β- and γ-secretases, the two enzymatic machines involved in Aβ genesis. Under physiological conditions, NF-κB lowers the transcriptional activity of the promoters of βAPP, β-secretase (β-site APP-cleaving enzyme 1, BACE1), and of the four protein components (Aph-1, Pen-2, nicastrin, presenilin-1, or presenilin-2) of the γ-secretase in HEK293 cells. This was accompanied by a reduction of both protein levels and enzymatic activities, thereby ultimately yielding lower amounts of Aβ and AICD (APP intracellular domain). In stably transfected Swedish βAPP-expressing HEK293 cells triggering supraphysiological concentrations of Aβ peptides, NF-κB activates the transcription of βAPP, BACE1, and some of the γ-secretase members and increases protein expression and enzymatic activities, resulting in enhanced Aβ production. Our pharmacological approach using distinct NF-κB kinase modulators indicates that both NF-κB canonical and alternative pathways are involved in the control of Aβ production. Overall, our data demonstrate that under physiological conditions, NF-κB triggers a repressive effect on Aβ production that contributes to maintaining its homeostasis, while NF-κB participates in a degenerative cycle where Aβ would feed its own production under pathological conditions.
    Journal of Biological Chemistry 07/2012; 287(29):24573-84. · 4.77 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

Alzheimer's disease
 
amyloid precursor protein
 
APP metabolites
 
broad range
 
CD40 deficiency mitigates amyloid deposition
 
CD40/CD40L interaction
 
CD40L stimulation
 
central nervous system
 
human embryonic kidney cells
 
inflammatory responses
 
key component
 
ligand CD40L mediates
 
NF-kappaB pathway
 
NFkappaB inhibitors
 
pharmacologically inhibiting CD40/CD40L interaction
 
PSAPP AD mouse model
 
PSAPP mouse models
 
therapeutic approaches
 
transgenic mouse models
 
tumor necrosis factor