Photobiomodulation by low-power laser irradiation attenuates Aβ-induced cell apoptosis through the Akt/GSK3β/β-catenin pathway

Apoptosis induced by amyloid beta peptide (A beta) is thought to associate with the pathogenesis of Alzheimer disease (AD). Accumulating evidence shows that low-power laser irradiation (LPLI) is capable of reducing A beta-induced apoptosis. However, the underlying mechanisms remain unclear. In this study, we report a novel molecular mechanism by which LPLI attenuates A beta(25-35)-induced apoptosis through the Akt/GSK3 beta/beta-catenin pathway. We found that Akt activated by LPLI interacted with GSK3 beta and phosphorylated it on Ser9 in the presence of A beta(25-35), which resulted in the inhibition of GSK3 beta. Furthermore, LPLI increased the nuclear translocation of beta-catenin and enhanced its T cell factor/lymphocyte enhancer factor-dependent transcriptional activity via the Akt/GSK3 beta pathway to promote cell survival upon treatment with A beta(25-35). Our data demonstrate that LPLI has a prosurvival effect on A beta-induced apoptosis and may be an effective therapeutic strategy in treating AD by targeting GSK3 beta. (C) 2012 Elsevier Inc. All rights reserved.