Small molecule LX2343 ameliorates cognitive deficits in AD model mice by targeting both amyloid ß production and clearance.

ABSTRACT

AIM: Streptozotocin (STZ) is widely used to induce oxidative damage and to impair glucose metabolism, apoptosis, and tau/Aß pathology, eventually leading to cognitive deficits in both in vitro and in vivo models of Alzheimer's disease (AD). In this study, we constructed a cell-based platform using STZ to induce stress conditions mimicking the complicated pathologies of AD in vitro, and evaluated the anti-amyloid effects of a small molecule, N-(1,3-benzodioxol-5-yl)-2-[5-chloro-2-methoxy(phenylsulfonyl)anilino]acetamide (LX2343) in the amelioration of cognitive deficits in AD model mice. METHODS: Cell-based assays for screening anti-amyloid compounds were established by assessing Aß accumulation in HEK293-APPsw and CHO-APP cells, and Aß clearance in primary astrocytes and SH-SY5Y cells after the cells were treated with STZ in the presence of the test compounds. Autophagic flux was observed using confocal laser scanning microscopy. APP/PS1 transgenic mice were administered LX2343 (10 mg·kg-1·d-1, ip) for 100 d. After LX2343 administration, cognitive ability of the mice was evaluated using Morris water maze test, and senile plaques in the brains were detected using Thioflavine S staining. ELISA assay was used to evaluate Aß and sAPPß levels, while Western blot analysis was used to measure the signaling proteins in both cell and animal brains. RESULTS: LX2343 (5-20 µmol/L) dose-dependently decreased Aß accumulation in HEK293-APPsw and CHO-APP cells, and promoted Aß clearance in SH-SY5Y cells and primary astrocytes. The anti-amyloid effects of LX2343 were attributed to suppressing JNK-mediated APPThr668 phosphorylation, thus inhibiting APP cleavage on one hand, and inhibiting BACE1 enzymatic activity with an IC50 value of 11.43±0.36 µmol/L, on the other hand. Furthermore, LX2343 acted as a non-ATP competitive PI3K inhibitor to negatively regulate AKT/mTOR signaling, thus promoting autophagy, and increasing Aß clearance. Administration of LX2343 in APP/PS1 transgenic mice significantly ameliorated cognitive deficits and markedly ameliorated the Aß pathology in their brains. CONCLUSION: LX2343 ameliorates cognitive dysfunction in APP/PS1 transgenic mice via both Aß production inhibition and clearance promotion, which highlights the potential of LX2343 in the treatment of AD.