SAGE-Hindawi Access to Research International Journal of Alzheimer’s Disease Volume 2009, Article ID 257403, 10 pages doi:10.4061/2009/257403 Research Article Evaluation of BACE1 Silencing in Cellular Models Malgorzata Sierant, 1 Katarzyna Kubiak, 1 Julia Kazmierczak-Baranska, 1 Masaki Warashina, 2 Tomoko Kuwabara, 2 and Barbara Nawrot 1 1 Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland 2 Organ Development Research Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba Science City, 305-8562 Ibaraki, Japan Correspondence should be addressed to Barbara Nawrot, bnawrot@bio.cbmm.lodz.pl Received 6 March 2009; Revised 1 June 2009; Accepted 11 June 2009 Recommended by Brian Austen Beta-secretase (BACE1) is the major enzyme participating in generation of toxic amyloid-beta (Aβ) peptides, identified in amyloid plaques of Alzheimer’s disease (AD) brains. Its downregulation results in decreasing secretion of Aβ. Thus, BACE1 silencing by RNAi represents possible strategy for antiamyloid therapy in the treatment of AD. In this study, a series of newly designed sequences of synthetic and vector-encoded siRNAs (pSilencer, pcPURhU6, and lentivirus) were tested against overexpressed and endogenous BACE1 in several cell lines and in adult neural progenitor cells, derived from rat hippocampus. SiRNAs active in human, mouse, and rat cell models were shown to diminish the level of BACE1. In HCN A94 cells, two BACE1-specific siRNAs did not alter the expression of genes of BACE2 and several selected genes involved in neurogenesis (Synapsin I, βIII-Tubulin, Calbidin, NeuroD1, GluR2, CREB, MeCP2, PKR), however, remarkable lowering of SCG10 mRNA, coding protein of stathmin family, important in the development of nervous system, was observed. Copyright © 2009 Malgorzata Sierant et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1. Introduction Alzheimer’s disease (AD) is a progressive brain disease affect- ing the elderly population, causing problems with memory, thought, and behavior. Approximately 2–5% of AD cases are familial (FAD), caused by autosomal dominant mutations in amyloid precursor protein (APP) or the presenilin (PS1, PS2) genes [1–3], while the majority of sporadic AD cases are not associated with any known mutations. The hallmarks of Alzheimer disease include intraneuronal neurofibrillary tangles, consisting of the hyperphosphorylated microtubule- associated protein Tau and extracellular deposits of fila- ments of 42-residue amyloid β (Aβ) peptide [4, 5]. Aβ deposits become increasingly fibrilar and gradually acquire the classical features of amyloid plaques [6]. Aβ is the product of sequential cleavage of APP by β- and γ-secretases [7, 8]. Nonharmful APP cellular processing by α- and γ- secretases results in a short, highly soluble, nonamylogenic p3 peptide [9]. In alternative amyloidogenic processing, APP is hydrolyzed by β- and γ-secretases, and three possible pep- tides (Aβ40, Aβ42, Aβ43) can be generated [10]. Variability of the cleavage site of γ-secretase is associated with mutations in the PS1 and PS2 genes [11]. Aβ peptides are secreted from the presynaptic terminal into the extracellular matrix, where fibrillary Aβ deposits are formed outside of neurons. Some evidences suggest that the Aβ aggregates are the critical factor which triggers a complex pathological cascade leading to neurodegeneration [12]. All strategies to lower brain Aβ42 levels should be therapeutically beneficial in AD treatment. Given that BACE1 is the initiating enzyme in Aβ generation, it is considered a prime target for drug in AD for reducing cerebral Aβ levels [13–15]. RNA interference (RNAi) is an eukaryotic regulatory mechanism that uses double-stranded RNA (dsRNA) for induction of posttranscriptional gene silencing by the sequence-specific hydrolysis of homologous mRNA [16, 17]. RNAi has already been proposed for therapy of neurode- generative diseases, including amyotrophic lateral sclerosis (ALS) [18], spinocerebellar ataxia (SCA) [19], Hunting- ton’s disease [20], and Alzheimer’s disease [21–23]. Using lentiviral vectors expressing siRNAs targeting BACE1, Singer et al. reduced the cleavage of APP at the beta site, lowered