Y, Hu

SummaryAimsFibrillar aggregates of β‐amyloid protein (Aβ) are the main constituent of senile plaques and considered to be one of the causative events in the pathogenesis of Alzheimer's disease (AD). Compounds that could inhibit Aβ fibrils formation, disaggregate preformed Aβ fibrils as well as reduce their associated neurotoxicity might have therapeutic values for treating AD. In this study, the inhibitory effects of bis (heptyl)‐cognitin (B7C), a multifunctional dimer derived from tacrine, on aggregation and neurotoxicity of Aβ1‐40 were evaluated both in vitro and in vivo.MethodsThioflavin T fluorescence assay was carried out to evaluate Aβ aggregation, MTT and Hoechst‐staining assays were performed to investigate Aβ‐associated neurotoxicity. Fluorescent probe DCFH‐DA was used to estimate the accumulation of intracellular reactive oxygen stress (ROS). Morris water maze was applied to determine learning and memory deficits induced by intracerebroventricular infusion of Aβ in rats.ResultsB7C (0.1–10 μM), but not tacrine, effectively inhibited Aβ fibrils formation and disaggregated preformed Aβ fibrils following co‐incubation of B7C and Aβ monomers or preformed fibrils, respectively. In addition, B7C markedly reduced Aβ fibrils‐associated neurotoxicity in SH‐SY5Y cell line, as evidenced by the increase in cell survival, the decrease in Hoechst‐stained nuclei and in intracellular ROS. Most encouragingly, B7C (0.1 and 0.2 mg/kg), 10 times more potently than tacrine (1 and 2 mg/kg), inhibited memory impairments after intracerebroventricular infusion of Aβ in rats, as evidenced by the decrease in escape latency and the increase in the spatial bias in Morris water maze test along with upregulation of choline acetyltransferase activity and downregulation of acetylcholinesterase activity.ConclusionThese findings provide not only novel molecular insight into the potential application of B7C in treating AD, but also an effective approach for screening anti‐AD agents.

SummaryAimsNeurodegenerative disorders are caused by progressive neuronal loss in the brain, and hence, compounds that could promote neuritogenesis may have therapeutic values. In this study, the effects of bis(heptyl)‐cognitin (B7C), a multifunctional dimer, on neurite outgrowth were investigated in both PC12 cells and primary cortical neurons.MethodsImmunocytochemical staining was used to evaluate the proneuritogenesis effects, and Western blot and short hairpin RNA assays were applied to explore the underlying mechanisms.ResultsB7C (0.1–0.5 μM) induced robust neurite outgrowth in PC12 cells, as evidenced by the neurite‐bearing morphology and upregulation of growth‐associated protein‐43 expression. In addition, B7C markedly promoted neurite outgrowth in primary cortical neurons as shown by the increase in the length of β‐III‐tubulin‐positive neurites. Furthermore, B7C rapidly increased ERK phosphorylation. Specific inhibitors of alpha7‐nicotinic acetylcholine receptor (α7‐nAChR) and MEK, but not those of p38 or JNK, blocked the neurite outgrowth as well as ERK phosphorylation induced by B7C. Most importantly, genetic depletion of α7‐nAChR significantly abolished B7C‐induced neurite outgrowth in PC12 cells.ConclusionB7C promoted neurite outgrowth through the activation of α7‐nAChR/ERK pathway, which offers novel insight into the potential application of B7C in the treatment of neurodegenerative disorders.