Mechanistic insights into cannabidiol-mediated TrkB activation via FRS2 interaction in attenuating Alzheimer's disease pathology and cognitive impairment.

Alzheimer's disease (AD) is characterized by progressive synaptic failure, neuroinflammation, amyloid and tau pathology, yet effective disease-modifying therapies remain limited. Cannabidiol (CBD) has shown neuroprotective potential in AD, but its direct molecular targets and signaling mechanisms remain unclear. Here, we demonstrate that CBD ameliorates cognitive and emotional deficits in 3×Tg-AD mice by restoring synaptic integrity and plasticity. At the mechanistic level, CBD activated TrkB signaling independently of BDNF, leading to suppression of tau hyperphosphorylation via the PI3K/AKT/GSK3β pathway and attenuation of neuroinflammation and amyloid pathology through inhibition of the JAK2/STAT3/SOCS1 axis. Using isothermal shift assays combined with biophysical binding analyses, we identified FRS2, a core adaptor protein of TrkB, as a direct molecular target of CBD. Molecular dynamics simulations further revealed that CBD stabilizes the FRS2-TrkB interface, thereby facilitating TrkB activation. Importantly, genetic knockdown of FRS2 abolished CBD-induced TrkB signaling and its downstream neuroprotective effects in both cellular and in vivo AD models. Together, these findings identify FRS2 as a critical signaling node mediating BDNF-independent TrkB activation by CBD and establish a mechanistic framework linking CBD to disease-modifying pathways in AD.