Polysaccharides from Wolfberry (Lycium barbarum) antagonize homocysteine-induced neurotoxicity in cultured cortical neurons

Abstract

Elevation of plasma homocysteine (Hcy) level is associated with a number of neurological disorders including Alzheimer’s disease (AD). The underlying mechanisms remain unclear. It has been suggested that high level of Hcy could induce AD-like neuropathology such as tau phosphorylation and increase Aβ production. Wolfberry (Lycium barbarum) is an oriental herb that is famous for its eye-protecting and anti-aging properties. Previous studies suggested that its polysaccharides, named as LBA, can protect neurons against Aβ and glutamate neurotoxicity. In this study, we investigate the possible protective effects of LBA on Hcy neurotoxicity. We found that treatment of LBA reduced Hcy-induced cell death and apoptosis in primary cortical neurons. LBA also attenuated Hcy-induced tau cleavage and tau phosphorylation at tau-1 (Ser198/199/202), pS396 (Ser396) and pS404 (Ser404) epitopes. The level of p-GSK3β (Ser9/Tyr216) remained relatively unchanged in all detected time points. Treatment of LBA significantly suppressed Hcy-induced elevation of p-JNK and p-ERK. Taken together, our results show that LBA can protect neurons from Hcy toxicity. Its potential to act as a disease-modifying agent in the prevention of AD deserves further exploration.