Ganoderic Acid A Prevented Osteoporosis by Modulating the PIK3CA/p-Akt/TWIST1 Signaling Pathway

Osteoporosis is a disorder of decreased bone mass, microarchitectural deterioration, and fragility fractures. Ganoderma lucidum has been reported to have a variety of pharmacological activities, including immune regulation, anti-inflammation, antioxidation, sedative hypnosis, blood sugar and lipid regulation, and so on. However, the effective ingredients and the underlying mechanism of Ganoderma lucidum against osteoporosis are rarely clarified. Ganoderic acid A (GA-A), a triterpenoid, is one of the main components of Ganoderma lucidum. Our previous preliminary bioinformatic study found that it may affect bone metabolism, and it has been reported that GA-A has anti-osteoporosis potential via regulating MC3T3-E1 cells' osteogenic differentiation activity. Therefore, the aim of this study is to investigate the effects of Ganoderic acid A in preventing osteoporosis and uncover the potential mechanisms. In vivo, the 8-week-old C57BL/6J female mice were used to establish the osteoporosis model by ovariectomy (OVX). Two cell lines, MC3T3-E1 cells and primary osteoblasts, were used and induced with hydrogen peroxide (H₂O₂) to the state of oxidative stress in osteoporosis in vitro. We showed that Ganoderic acid A could inhibit OVX-induced bone loss in a dose-dependent manner and promote H₂O₂-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. The mechanism-related signaling pathways were identified by network pharmacology screening and verified by bioinformatics. Results predicted that the target of Ganoderic acid A might be PIK3CA. Mechanistically, we found that PIK3CA activated the Akt receptor, then inhibited the expression of TWIST1 in the osteoblasts to up-regulate the protein expression of the osteogenic-related markers. Our results suggested that Ganoderic acid A could prevent OVX-induced osteoporosis and promote H₂O₂-induced osteogenic differentiation of primary osteoblasts and MC3T3-E1 cells. Ganoderic acid A might play an important role in the prevention of osteoporosis by modulating the PIK3CA/p-Akt/TWIST1 signaling pathway.