Rapid Selenoprotein Activation by Selenium Nanoparticles to Suppresses Osteoclastogenesis and Pathological Bone Loss

Abstract Osteoclast hyperactivation stands as a significant pathological factor contributing to the emergence of bone disorders driven by heightened oxidative stress levels. The modulation of the redox balance to scavenge reactive oxygen species (ROS) emerges as a viable approach in addressing this concern. Selenoproteins, characterized by selenocysteine (SeCys 2 ) as the active center, are crucial for selenium‐based antioxidative stress therapy for inflammatory diseases. This study reveals that surface‐active elemental selenium (Se) nanoparticles, particularly those derived from lentinan (LNT‐Se), exhibit enhanced cellular accumulation and accelerated metabolism to SeCys 2 , the primary active Se form in biological systems. Consequently, LNT‐Se demonstrates significant inhibition of RANKL‐induced osteoclastogenesis and osteoclastic activity when compared to alternative Se species. Furthermore, in vivo studies underscore the superior therapeutic efficacy of LNT‐Se over SeCys 2 , potentially attributable to the enhanced stability and safety profile of LNT‐Se. Specifically, LNT‐Se effectively modulates the expression of the selenoprotein GPx1, thereby exerting regulatory control over macrophage polarization, osteoclast activity inhibition, and the prevention of CIA/OVX‐induced osteolysis. In summary, these results suggest that the prompt activation of selenoproteins by Se nanoparticles serves to suppress osteoclastogenesis and pathological bone loss by upregulating GPx1 to re‐polarize macrophages. Moreover, the utilization of bioactive Se species presents a promising avenue for effectively managing bone disorders, with considerable potential for clinical translation. This article is protected by copyright. All rights reserved