5-methoxyresorcinol mitigates postmenopausal osteoporosis through regulation of the PI3K-AKT-GSK3β signaling pathway...

Osteoporosis is a systemic skeletal disease characterized by excessive osteoclast-mediated bone resorption. This study aimed to evaluate the therapeutic potential of 5-methoxyresorcinol (MR) in osteoporosis and to clarify its underlying mechanisms.

Network pharmacology analysis was performed to identify shared targets between MR and osteoporosis. In vitro experiments using bone marrow-derived macrophages were performed to assess the effects of MR on osteoclast differentiation and function. In addition, the in vivo efficacy of MR was evaluated in an ovariectomized (OVX) mouse model using micro-CT and histological analyses.

Network pharmacology analysis identified 107 potential targets of MR and 8,060 osteoporosis-associated genes, of which 50 were overlapping targets. Among these targets, the PI3K-AKT signaling pathway showed significant enrichment. In vitro, MR at concentrations ≤1 mM showed no significant cytotoxicity and suppressed osteoclast differentiation in a dose-dependent manner. MR also inhibited osteoclast function by reducing the formation of F-actin ring and the secretion of acidified vesicles. Mechanistically, MR inhibited activation of the PI3K-AKT-GSK3β pathway, downregulated osteoclast-specific genes (DC-STAMP, OC-STAMP, CTSK, MMP-9, c-FOS, and NFATc1), and reduced RANKL-induced reactive oxygen species (ROS) generation. In OVX mice, MR improved bone microarchitecture and alleviated osteoporotic bone loss.

MR attenuates osteoporosis by suppressing osteoclast differentiation and function through regulating PI3K-AKT-GSK3β axis and ROS homeostasis, supporting its potential as a promisingtherapeutic candidate for osteoporosis.