Onishi Yoshiaki, Kawano Yasuhiro, Yamazaki Yoshimitsu
Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, Japan.
Cell Physiol Biochem. 2012;29(3-4):407-16. doi: 10.1159/000338495. Epub 2012 Apr 3.
Plants of the Amaryllidaceae family have been used as therapeutic agents against CNS related maladies such as Alzheimer's disease. The known primary alkaloid constituents have significant biological activity. We identified the Lycoris alkaloids lycorine and lycoricidinol from Amaryllidaceae using a real-time reporter gene assay system based on NIH3T3 cells. These alkaloids have a wide spectrum of pharmacological actions and dose-dependently lengthen the circadian period. When cells that had been incubated with lycorine or lycoricidinol were washed and then incubated without these alkaloids, period length reverted to that of control cells, suggesting that elongation of the circadian period induced by lycorine and lycoricidinol is reversible. Although one of its major activities is the inhibition of protein synthesis, lycorine induced dose-dependent period elongation regardless of the presence of cycloheximide and moreover, cycloheximide, itself did not affect period length, suggesting that lycorine dose-dependently extends the circadian period by a mechanism other than translational inhibition. Real-time RT-PCR showed that lycorine enhanced RORα and Bmal1 transcription, and exogenous expression and knockdown of Bmal1 also caused long and short periods, respectively, thus confirming the phenotype indicated by lycorine. These data indicate that lycorine and lycoricidinol modulate Bmal1 transcription and the circadian period, and also suggest that Lycoris alkaloids are novel contributors to the control of period length in mammalian cells.
石蒜科植物已被用作治疗与中枢神经系统相关疾病（如阿尔茨海默病）的治疗剂。已知的主要生物碱成分具有显著的生物活性。我们使用基于NIH3T3细胞的实时报告基因检测系统，从石蒜科植物中鉴定出了石蒜碱和石蒜西定醇。这些生物碱具有广泛的药理作用，并能剂量依赖性地延长昼夜节律周期。当用石蒜碱或石蒜西定醇孵育过的细胞被洗涤后，再在没有这些生物碱的情况下孵育，周期长度会恢复到对照细胞的水平，这表明石蒜碱和石蒜西定醇诱导的昼夜节律周期延长是可逆的。尽管石蒜碱的主要活性之一是抑制蛋白质合成，但无论是否存在环己酰亚胺，石蒜碱都会诱导剂量依赖性的周期延长，而且环己酰亚胺本身并不影响周期长度，这表明石蒜碱通过翻译抑制以外的机制剂量依赖性地延长昼夜节律周期。实时RT-PCR显示石蒜碱增强了RORα和Bmal1的转录，外源性表达和敲低Bmal1也分别导致周期延长和缩短，从而证实了石蒜碱所显示的表型。这些数据表明石蒜碱和石蒜西定醇调节Bmal1转录和昼夜节律周期，也表明石蒜科生物碱是哺乳动物细胞周期长度控制的新贡献者。
