Osteoporosis, a severe systemic skeletal disorder characterized by decreased bone mineral density, leads to increased risks of bone fragility and fracture. Although some herbal medicines are clinically used for treating osteoporosis, the crucial anti-osteoporotic constituents and their mechanisms have not been well-elucidated. Notum, a negative regulator of Wnt/β-catenin signaling, has been validated as a druggable target for enhancing cortical bone thickness and alleviating osteoporosis. Herein, we showcase an efficient strategy for uncovering the key anti-Notum constituents from herbal medicines via integrating biochemical, phytochemical, computational, and cellular assays. Following screening the anti-Notum potentials of herbal medicines, Polygonum multiflorum Thunb. (PM), a commonly used anti-osteoporosis herb , showed potent and competitive inhibition against Notum. Phytochemical profiling coupling with docking-based virtual screening suggested that three anthraquinones, including rhein, emodin, and chrysophanol, showed high binding-potency towards Notum. Biochemical assays validated that three anthraquinones were strong competitive inhibitors of Notum, while rhein was the most potent one (IC 50 = 9.98 nM). Cellular investigations demonstrated that rhein markedly promoted osteoblast differentiation in dexamethasone-challenged MC3T3-E1 osteoblasts, while RNA sequencing showed that rhein remarkably regulated Wnt signaling-related and osteogenic differentiation-related genes. In vivo tests showed that rhein displayed favorable safety profiles in healthy mice and this agent significantly elevated bone mineral density, augmented trabecula and cortical bone thickness in dexamethasone-induced osteoporotic mice. Collectively, this study showcases an efficient strategy for uncovering the key anti-Notum constituents from herbal medicines, while rhein was identified as a naturally occurring Notum inhibitor that shows favorable safety profiles and impressive anti-osteoporosis effects.
Notum, a negative feedback regulator of the Wnt signaling, has emerged as a promising target for treating glucocorticoid-induced osteoporosis (GIOP). This study showcases an efficient strategy for discovering the anti-Notum constituents from herbal medicines (HMs) as novel anti-GIOP agents. Firstly, a rapid-responding near-infrared fluorogenic substrate for Notum was rationally engineered for high-throughput identifying the anti-Notum HMs. The results showed that Bu-Gu-Zhi (BGZ), a known anti-osteoporosis herb, potently inhibited Notum in a competitive-inhibition manner. To uncover the key anti-Notum constituents in BGZ, an efficient strategy was adapted via integrating biochemical, phytochemical, computational, and pharmacological assays. Among all identified BGZ constituents, three furanocoumarins were validated as strong Notum inhibitors, while 5-methoxypsoralen (5-MP) showed the most potent anti-Notum activity and favorable safety profiles. Mechanistically, 5-MP acted as a competitive inhibitor of Notum via creating strong hydrophobic interactions with Trp128 and Phe268 in the catalytic cavity of Notum. Cellular assays showed that 5-MP remarkably promoted osteoblast differentiation and activated Wnt signaling in dexamethasone (DXMS)-challenged MC3T3-E1 osteoblasts. In dexamethasone-induced osteoporotic mice, 5-MP strongly elevated bone mineral density (BMD) and improved cancellous and cortical bone thickness. Collectively, this study constructs a high-efficient platform for discovering key anti-Notum constituents from HMs, while 5-MP emerges as a promising anti-GIOP agent.
危险品化学品经营许可证（带存储）