Affiliations: [a] School of Molecular and Cell Biology, University of the Witwatersrand, Wits, Johannesburg, Republic of South Africa (RSA) | [b] Department of Internal Medicine, University of the Witwatersrand, Johannesburg, Parktown, Republic of South Africa (RSA) | [c] Affimed GmbH, Technologiepark, Heidelberg, Germany | [d] Department of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, AB, Canada
Correspondence:
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Correspondence to: Stefan F.T. Weiss, School of Molecular and Cell Biology, University of the Witwatersrand, Private Bag 3, Wits 2050, Johannesburg, Republic of South Africa (RSA). Tel.: +2711717 6346; Fax: +27 11 7176351; E-mail: stefan.weiss@wits.ac.za
Note: [1] These authors contributed equally to this work.
Abstract: The neuronal perturbations in Alzheimer’s disease are attributed to the formation of extracellular amyloid-β (Aβ) neuritic plaques, composed predominantly of the neurotoxic Aβ42 isoform. Although the plaques have demonstrated a role in synaptic dysfunction, neuronal cytotoxicity has been attributed to soluble Aβ42 oligomers. The 37kDa/67kDa laminin receptor has been implicated in Aβ42 shedding and Aβ42-induced neuronal cytotoxicity, as well as internalization of this neurotoxic peptide. As the cellular prion protein binds to both LRP/LR and Aβ42, the mechanism underlying this cytotoxicity may be indirectly due to the PrPc-Aβ42 interaction with LRP/LR. The effects of this interaction were investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assays. PrPc overexpression significantly enhanced Aβ42 cytotoxicity in vitro, while PrP–/– cells were more resistant to the cytotoxic effects of Aβ42 and exhibited significantly less cell death than PrPc expressing N2a cells. Although anti-LRP/LR specific antibody IgG1-iS18 significantly enhanced cell viability in both pSFV1-huPrP1-253 transfected and non-transfected cells treated with exogenous Aβ42, it failed to have any cell rescuing effect in PrP–/– HpL3-4 cells. These results suggest that LRP/LR plays a significant role in Aβ42-PrPc mediated cytotoxicity and that anti-LRP/LR specific antibodies may serve as potential therapeutic tools for Alzheimer’s disease.
