siRNA against presenilin 1 (PS1) down regulates amyloid ß42 production in IMR-32 cells.

ABSTRACT

BACKGROUND: One of the pathological hallmarks of Alzheimer's disease (AD) is the deposition of the ~4 kDa amyloid ß protein (Aß) within lesions known as senile plaques. Aß is also deposited in the walls of cerebral blood vessels in many cases of AD. A substantial proportion of the Aß that accumulates in the AD brain is deposited as Amyloid, which is highly insoluble, proteinaceous material with a ß-pleated-sheet conformation and deposited extracellularly in the form of 5-10 nm wide straight fibrils. As γ-secretase catalyzes the final cleavage that releases the Aß42 or 40 from amyloid ß -protein precursor (APP), therefore, it is a potential therapeutic target for the treatment of AD. γ-Secretase cleavage is performed by a high molecular weight protein complex containing presenilins (PSs), nicastrin, Aph-1 and Pen-2. Previous studies have demonstrated that the presenilins (PS1 and PS2) are critical components of a large enzyme complex that performs γ-secretase cleavage. METHODS: In this study we used RNA interference (RNAi) technology to examine the effects of small-interfering RNA (siRNA) against PS1 on expression levels of PS1 and Aß42 in IMR-32 Cells using RTPCR, western blotting and immunofluorescence techniques. RESULTS: The results of the present study showed down regulation of PS1 and Aß42 in IMR32 cells transfected with siRNA against PS1. CONCLUSION: Our results substantiate the concept that PS1 is involved in γ-secretase activity and provides the rationale for therapeutic strategies aimed at influencing Aß42 production.