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Our previous study demonstrated that huperzine A, a selective acetylcholinesterase inhibitor, stimulates the synthesis of nerve growth factor (NGF) in cultured rat cortical astrocytes. The present studies are designed to examine if huperzine A exerts its neuroprotective activity against oxidative stress damage through increasing the synthesis of NGF in SHSY5Y neuroblastoma cells. Transient exposure of the cells to 200 microM H2O2 triggered a significant reduction of cell viability and decreased the mRNA and protein levels of NGF, neurotrophin receptor P75 (P75NTR) receptor and tyrosine kinase A (TrkA) receptor. Incubation of cells with 10 microM huperzine A prior to H2O2 exposure significantly elevated their survival and restored the mRNA and protein levels of NGF, P75NTR receptor and TrkA receptor. These neuroprotective effects of huperzine A on H2O2-induced cytotoxicity were blocked by the TrkA receptor phosphorylation inhibitor K252alpha, and were antagonized by the mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) inhibitor, PD98059. The present results indicate that the cytoprotective effect of huperzine A is mediated at least partly by up-regulated NGF and NGF receptors. The results also show that the MAP/ERK kinase signal pathway is crucial for huperzine A to protect against H2O2-induced damage in SHSY5Y cells.

Abstract: Huperzine A (HupA), a novel Lycopodium alkaloid isolated from Chinese folk medicine Huperzia serrata (Qian Ceng Ta), is a potent, selective and well-tolerated inhibitor of acetylcholinesterase (AChE). It has been proven to significantly improve the learning and memory impairment in Alzheimer''s disease (AD) and vascular dementia (VaD) patients in China. Interestingly, our recent data indicate that HupA also possesses other protective functions. This paper will give an overview on the protective effects of HupA, which includes regulating β-amyloid precursor protein (APP) metabolism, protecting against Aβ-mediated oxidative stress, apoptosis and mitochondrial dysfunction, as well as anti-inflammation. The multiple neuroprotective effects of HupA might yield additional beneficial effects in AD and VaD therapy. [Copyright &y& Elsevier]