The influence of Schisandrin B on a model of Alzheimer's disease using β-amyloid protein Aβ1-42-mediated damage in SH-SY5Y neuronal cell line and underlying mechanisms

Schisandrin B, an active substance, is derived from Chinese herb fruit Wuweizi, which exerts various pharmacological activities and has displayed significant beneficial effects in ameliorating Alzheimer's disease (AD). The aim of this study was to further extend our examination for the use of schisandrin B extract in the potential treatment of AD effects by investigating DNA methylation (DNMT), known to be modified in this disease using SH-SY5Y neuronal cell line exposed to beta-amyloid protein (A beta(1-42)). In particular, the purpose of this investigation was to examine alterations in mRNA and protein expression of DNMT. Data demonstrated that schisandrin B blocked A beta(1-42)-mediated injury in SH-SY5Y neuronal cell line as evidenced by a restoration of cellular morphology and cell viability to approximate control levels at the highest 10 mu g/ml Schisandrin B. Incubation with A beta(1-42) significantly decreased mRNA and protein expression of DNMT3A and DNMT1 in SH-SY5Y neuronal cell line. Incubation with A beta(1-42) followed by 24 treatment with schisandrin B significantly inhibited the A beta(1-42)-induced changes in mRNA and protein expression of DNMT3A and DNMT3B in a concentration-dependent manner. It is of interest that the mRNA expression of DNMT3A and DNMT1 were significantly higher than control. Data thus indicate schisandrin B was effective in inhibiting the actions of A beta(1-42) on cell survival and morphology and that DNA methylation may be associated with the beneficial findings.