7,8-Dihydroxyflavone ameliorates bone loss by regulating TRKB/AKT/FOXO3a pathway in a mouse model of alzheimer's...

The incidence of osteoporosis is increased in Alzheimer's disease (AD). The pathogenesis of AD with osteoporosis is still unknown, there is no ideal treatment as yet for it. 7,8-Dihydroxyflavone (7,8-DHF), a functional brain-derived neurotrophic factor (BDNF) mimetic, shows therapeutic potential for neurological and orthopedic disorders.

This research investigated the molecular mechanisms by which 7,8-DHF mitigates bone loss and cognitive dysfunction in osteoporotic AD mice.

Micro-CT analysis quantified bone loss in AD mice. The Morris water maze (MWM) assessed mouse cognitive function, and immunohistochemical analysis measured Aβ plaque deposition. qPCR and Western blotting measured expression levels of APP, Aβ42, TRKB, and FOXO3a in osteoblasts isolated from femoral bone marrow mesenchymal stem cells (BMSCs) and brain tissue. ELISA determined the levels of IL-1β, IL-6, osteocalcin (OCN), fibroblast growth factor 23 (FGF23) and sclerostin. For in vitro experiments, osteoblast differentiation was monitored in MC3T3-E1 cells co-cultured with Aβ42, with concurrent measurement of TRKB, AKT, and FOXO3a expression. The efficacy of 7,8-DHF against bone loss and osteoblast differentiation was systematically evaluated.

Cognitive impairment and bone loss manifested in APP/PS1 mice. 7,8-DHF treatment ameliorated bone mass reduction, decreased Aβ42 expression in bone tissue, and enhanced TRKB expression. Concurrently, 7,8-DHF improved cognitive function and accelerated clearance of [¹²⁵I]-Aβ42 from the brain. In in-vitro, Aβ42 increased inflammatory cytokine levels, suppressed TRKB expression, and impaired osteoblast differentiation. 7,8-DHF reduced the levels of AKT and pFOXO3a by TRKB.

7,8-DHF could alleviate bone mass loss in AD mice by regulating the TRKB/AKT/FOXO3a pathway. This finding provides new ideas for the treatment strategy of AD with osteoporosis and is beneficial to the health of the elderly.