N-linoleyltyrosine protects neurons against Aβ-induced cell toxicity via autophagy involving the CB/AMPK/mTOR/ULK1 pathway.

Beta-amyloid protein (Aβ) 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 Aβtreated primary cortical neurons for the first time in vitro. NITyr treatment attenuated cytotoxicity induced by Aβ, 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 CB 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 Aβ-induced cytotoxicity by inducing autophagy, which involved the CB/AMPK/mTOR/ULK1 pathway.