Total alkaloids from the seed embryo of Nelumbo nucifera Gaertn. improve cognitive impairment in APP/PS1 mice and protect Aß-damaged PC12 cells.

The seed embryo of Nelumbo nucifera Gaertn. is a famous traditional Chinese medicine and food which is considered conducive to the prevention of Alzheimer's disease (AD). In this study, the effect and mechanism of TASENN (total alkaloids from the seed embryo of Nelumbo nucifera Gaertn.) on AD mice and amyloid-ß (Aß) injured PC12 cells were evaluated. HPLC-UV analysis showed that the extracted TASENN (purity = 95.6%) mainly contains Liensinine, Isoliensinine, and Neferine (purity was 23.01, 28.02, and 44.57%, respectively). In vivo, oral treatment with TASENN (50 mg/kg/day for 28 days) improved the learning and memory functions of APP/PS1 transgenic mice, ameliorated the histopathological changes of cortical and hippocampal neurons, and inhibited neuronal apoptosis. We found that TASENN reduced the phosphorylation of Tau and the formation of neurofibrillary tangles (NFTs) in APP/PS1 mouse brain. Moreover, TASENN down-regulated the expression of APP and BACE1, ameliorated Aß deposition, and inhibited microglial proliferation and aggregation. The elevated protein expression of CaM and p-CaMKII in APP/PS1 mouse brain was also reduced by TASENN. In vitro, TASENN inhibited the apoptosis of PC12 cells injured by Aß25-35 and increased the cell viability. Aß25-35-induced increase of cytosolic free Ca2+ level and high expression of CaM, p-CaMKII, and p-Tau were decreased by TASENN. Our findings indicate that TASENN has a potential therapeutic effect on AD mice and a protective effect on PC12 cells. The anti-AD activity of TASENN may be closely related to its negative regulation of the CaM pathway.

Protective effects of Liensinine, Isoliensinine, and Neferine on PC12 cells injured by amyloid-ß.

Excessive accumulation of amyloid-ß (Aß) is the leading cause of Alzheimer's disease (AD). Liensinine, Isoliensinine, and Neferine are main alkaloids in lotus seed embryos. In this paper, the protective effects of Liensinine, Isoliensinine, and Neferine on Aß25-35 -injured PC12 cells were studied. It was found that Liensinine, Isoliensinine, and Neferine could improve the viability and reduce the apoptosis of PC12 cell induced by Aß25-35 . These three alkaloids could also reduce the level of intracellular free Ca2+ and CaM expression in Aß25-35 -treated cells, thereby inhibiting the phosphorylation of CaMKII and tau. In addition, these three compounds can inhibit the production of ROS in PC12 cells injured by Aß25-35 . Our results suggest for the first time that Liensinine, Isoliensinine, and Neferine can inhibit hyperphosphorylation of tau protein by inhibiting the Ca2+ -CaM/CaMKII pathway, thereby reducing the apoptosis and death of PC12 cells damaged by Aß25-35 . PRACTICAL APPLICATIONS: This study highlighted the protective effects and mechanisms of three main active ingredients (Liensinine, Isoliensinine, and Neferine) in the lotus embryo on a typical cell model of Alzheimer's disease (AD). The results revealed that three alkaloids in this healthy food might exert therapeutic potential for AD.

Selenoprotein SELENOK Enhances the Migration and Phagocytosis of Microglial Cells by Increasing the Cytosolic Free Ca2+ Level Resulted from the Up-Regulation of IP3R.

Enhancing the migration and phagocytosis of microglial cells is of great significance for the reducing of the risk of the neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The effect of mouse selenoprotein K (mSELENOK) on the migration and phagocytosis of BV2 microglial cells and its mechanism were studied. The results showed that the over-expression of mSELENOK can increase the migratory and phagocytic abilities of the microglial cells, while the knockdown of mSELENOK can decrease the migratory and phagocytic abilities of the cells. The cytosolic free Ca2+ level and inositol trisphosphate receptor (IP3R) mRNA transcript and protein expression were also increased significantly as the consequence of the over-expression of mSELENOK in the microglial cells. On the contrary, the level of cytosolic free Ca2+ and the mRNA transcript and protein expression of IP3R in mSELENOK knockdown cells were decreased significantly. 2-aminoethoxydiphenyl borate (2-APB), an antagonist of IP3R, could prevent the increased migration, phagocytosis, and cytosolic free Ca2+ level of mSELENOK over-expressed microglial cells, and knockdown of IP3R3 could reduce the increased cytosolic Ca2+ level in mSELENOK over-expressed microglial cells. Further studies revealed that selenium supplement (Na2SeO3) can increase the expression of mSELENOK in microglial cells significantly. In summary, these data suggest that mSELENOK can increase cytosolic free Ca2+ level of microglial cells by up-regulating the expression of IP3R, thus enhancing the migration and phagocytosis of microglial cells. Our results indicated that mSELENOK is an important selenoprotein, which plays a role in trace element selenium's functions and can enhance the migration and phagocytosis of microglial cells.