MAPK3 and Alzheimer disease: AD-MSCs were pre-treated with CB2 agonist (5 μM, 12 h) in the presence or absence of AM630 (4μM, a CB2 inhibitor), U0126 (5μM, an Erk1/2 inhibitor), LY294002 (5μM, a PI3K/Akt inhibitor) or AG490 (a Stat3 inhibitor, 40μM), all from Selleck Chemicals (Houston, TX, USA).