A Novel Derivative Of Xanomeline EUK1001 Improved Neurogenesis In Mice

Cholinergic system of the brain systemically participated in the exertion of cognitive function and regulation of neurogenesis. It is also involved in the process of neurodegenerative diseases such as Alzheimer's disease (AD). The M1 receptor was highly expressed in forbrain and hippocampal area. Xanomeline, an agonist of M1 receptor, is in clinical trial for AD, which could alleviate pathological syndrome of AD and improve the cognitive function. The compound has a number of side effects, such as desudation, salivation and gastrointestinal discomforts. It was reported in previous studies in our lab that EUK1001, which is a novel derivative of xanomeline, could improve learning and memory in aged mice and enhance the synaptic plasticity in hippocampus. It is also noticeable that when compared with xanomeline, EUK1001 has less side effects.Based on the impacts of EUK1001 on aged mice and the relationship between cognitive function and neurogenesis, we postulated that it might affect the neurogenesis of adult mice. In order to testify the hypothesis, C57BL/6J mice were administered with EUK1001 for 15 days and injected with BrdU, which is a thymine analog and used to label the newly generated neural cells. The change of newly generated neural cells was detected through immunohistochemistry by double-labeled BrdU and biological markers which were particularly expressed during the different stages of differentiation and maturation. We have found that EUK1001 could promote the proliferation of hippocampal neural progenitor cells and survival of newly generated neural cells, but had marginal effects on the differentiation of neural cells and neurogenesis of SVZ in lateral ventricles.In order to reveal the mechanism underlying increased neurogenesis by EUK1001 treatment, the expression of six genes in hippocampus were analyzed by real-time fluorescence quantitative PCR (RT-PCR). These genes were reported in literatures that involved in regulation of adult neurogenesis, included cAMP responsive element binding protein 1 (Creb1), paired box gene 6 (Pax6), vascular endothelial growth factor A (VEGFa), neurogenic differentiation 1 (Neurodl), brain derived neurotrophic factor (BDNF) and wingless-related MMTV integration site 3A (Wnt3a). Our results demonstrated that the expression of BDNF was markedly increased after EUK1001 treatment.We have shown that fifteen days EUK1001 treatment upregulated the expression of BDNF and promoted the proliferation of neural progenitor cells and survival of newborn neural cells in hippocampus. It could be involved in the improvement of cognitive function in mice. Compared with xanomeline, EUK1001 exhibits higher efficiency for improving cognitive function and produces significantly less deleterious side effects, suggesting that it could be developed into a promising therapeutic agent for the treatment of AD and age-related memory disorders.