MAPT and Alzheimer disease: All results uncover that HGF secreted from hUC‐MSCs, mediates the beneficial effects of hUC‐MSCs on functional recovery of damaged neural cells by downregulating hyperphosphorylated tau, improving neurofibrillary tangles, reversing spine loss, and promoting synaptic plasticity in AD hippocampus through the cMet‐AKT‐GSK3β signaling pathway.