Probucol attenuates bone loss in APP/PS1 mice and ameliorates Aβ42-induced osteoblast dysfunction by regulating AKT/FOXO3a signaling pathway.

Abstract

BACKGROUND: Alzheimer's disease (AD) and osteoporosis are common age-related degenerative diseases. Emerging evidence suggests that amyloid-β (Aβ) deposition may contribute to the pathogenesis of both conditions. This study investigated whether probucol could alleviate AD-associated bone loss and Aβ42-induced osteoblast dysfunction, and further explored the underlying mechanisms. METHODS: Female mice were divided into four groups (n = 5 per group): C57BL/6 wild-type (WT), WT treated with probucol (WT + PBC), APP/PS1 transgenic (AD) mice, and AD treated with probucol (AD+PBC). Bone mineral density (BMD) was assessed by micro-CT. Levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) along with bone metabolism markers including fibroblast growth factor 23 (FGF23), sclerostin, and brain-derived neurotrophic factor (BDNF) in bone and brain tissues were measured by ELISA. FOXO3a was knocked down in the bone marrow of APP/PS1 mice via stereotactic injection of lentiviral vectors. Expression of APP and FOXO3a in bone tissue was evaluated using RT-qPCR and Western blotting (WB). Mitochondrial damage in osteoblasts and neuronal cells was assessed by transmission electron microscopy (TEM). In vitro study, osteoblast differentiation and mineralization deficits were evaluated using Alizarin Red staining. WB was used to measure the expression of AKT, FOXO3a, autophagy and apoptosis related proteins. RESULTS: Probucol attenuated bone loss and mitochondrial damage in both APP/PS1 and FOXO3a-knockdown APP/PS1 mice, and improved cognitive impairment and neuronal ultrastructure in APP/PS1 mice. Furthermore, probucol attenuated Aβ42-induced osteoblast differentiation and mineralization via the AKT/FOXO3a signaling pathway in vitro. CONCLUSION: These findings demonstrate that probucol ameliorates AD-associated bone loss and Aβ42-induced osteoblast impairments by regulating AKT/FOXO3a signaling pathway.