N-linoleyltyrosine protects neurons against Aß1-40-induced cell toxicity via autophagy involving the CB2/AMPK/mTOR/ULK1 pathway.

Beta-amyloid protein (Aß) is one of the most important pathogenic factors of Alzheimer's disease (AD). N-linoleyltyrosine (NITyr) was synthesized in our laboratory and exerted neuroprotective effects in APP/PS1 transgenic mice in previous reports. In this study, the neuroprotective effects and mechanisms of NITyr were evaluated in Aß1-40-treated primary cortical neurons for the first time in vitro. NITyr treatment attenuated cytotoxicity induced by Aß1-40, and the best effect of NITyr was observed at 1 µmol/L. NITyr treatment increased the BDNF protein expression and the ratio of p-CREB/CREB, but weakened the Caspase-3 protein expression. Meanwhile, NITyr enhanced the expressions of autophagy-related proteins (LC3-II, Beclin-1, ATG5 and ATG13). The autophagy inhibitor 3-methyladenine (3MA) reversed the effects of NITyr on cell viability and the protein expressions of neuron-related proteins, including BDNF, p-CREB and Caspase-3. The CB2 receptor antagonist AM630 weakened the neuroprotective effects of NITyr and the autophagy-related protein expression (LC3-II, Beclin-1, ATG5 and ATG13). Moreover, NITyr significantly increased the expressions of p-AMPK, p-mTOR and p-ULK1, but not p-p38. AM630 ablated the above phenomenon. Therefore, NITyr protected the neurons against Aß1-40-induced cytotoxicity by inducing autophagy, which involved the CB2/AMPK/mTOR/ULK1 pathway.

Calycosin suppresses colorectal cancer progression by targeting ERß, upregulating PTEN, and inhibiting PI3K/Akt signal pathway.

High intake of phytoestrogen has been reported to be associated with the prevention of colorectal cancer (CRC). Calycosin belongs to the phytoestrogen that has been shown to suppress CRC cells in our previous study. However, its anticancer activity and molecular mechanisms have not been elucidated. In this study, we analyzed the effect of calycosin on the viability and apoptosis of human CRC HCT116 and SW480 cells via MTT assay, flow cytometry assay, and caspase-3/7 activity assay. The protein expressions of estrogen receptor ß (ERß), PTEN, and PI3K/Akt signal pathways were determined by Western blot analysis. And then, the alterations of biological behavior in CRC cells transfected with ERß siRNA were analyzed. Mouse xenograft models were further performed to detect the antitumor effect in vivo. The results show that calycosin reduces CRC cell viability, induces cell apoptosis, and suppresses xenograft tumor growth. The protein expressions of ERß and PTEN are significantly upregulated following calycosin treatment, whereas p-AKT/AKT ratio and Bcl-2 level are downregulated. Suppressing ERß with siRNA partially attenuates the reduction in viability and apoptosis induced by calycosin. Our results indicate that calycosin shows inhibitory effects on CRC cells, which might be obtained by targeting ERß, upregulating PTEN, and inhibiting the PI3K/Akt signal pathway.

Indirect Competitive Determination of Tetracycline Residue in Honey Using an Ultrasensitive Gold-Nanoparticle-Linked Aptamer Assay.

Tetracycline residue in honey has become an increasingly important food safety problem. In this work, an ultrasensitive gold nanoparticles (AuNPs)-linked aptamer assay was developed to determine the tetracycline residue in honey. First, a tetracycline-bovine serum albumin conjugate coating was applied to a microplate. Then, with the incubation of AuNPs-linked aptamer, the fixed tetracycline in the microplate competed for the limited aptamer with the free tetracycline in the sample. Higher amounts of free tetracycline in the sample were associated with more competitive binding of aptamer-AuNPs, and the aptamer-AuNPs binding with tetracycline-BSA was lower. Finally, as a kind of nanozyme, AuNPs exhibited peroxidase activity and oxidized 3,3',5,5'-tetramethylbenzidine, transforming it from colorless to blue, and achieving the measurement at 652 nm. The analytical performance-including linearity, limit of detection, selectivity, precision, repeatability, and accuracy-has been investigated. It was successfully applied to the determination of tetracycline in honey samples with high accuracy and sensitivity.

[Effect of caffeic acid, seopoletin and scutellarin on rat retinal neurons in vitro].

OBJECTIVE: To observe the effect of caffeic acid, seopoletin and scutellarin on rat retinal neurons in vitro and explore neuroprotection in glaucoma of Erigeron breviscapus. METHOD: The retinal of 18 post-natal 2-3 days Sprague-Dawley rats were dissociated into cell suspension with trypsin digestion. The cell suspension was implated in 96-well culture plates covered with hyaluronic acid and laminin in each well. After culturing for 3 days, caffeic acid, seopoletin and scutellarin were added to the cultures, continue to culture 2 days. Then, the A of living cells in each well was tested by MTT colorimetric microassay. Some of the 5-day culture cells were identified by Nissel technique. RESULT: Most of the living cells were retinal neurons by Nissel identification. The number of living cells increased significantly in high concentrations of caffeic acid, seopoletin and scutellarin compared with control group (P < 0.05, P < 0.01). CONCLUSION: caffeic acid, seopoletin and scutellarin can all promote retinal neurons to live in vitro, with caffeic acid being most effective.