末梢神経-骨クロストークにおけるPTEN/AKT軸を介したシュワン細胞由来細胞外小胞による破骨細胞形成の阻害

Osteoclasts, the sole bone-resorbing cells, play a central part in bone homeostasis, and their overactivation is implicated in bone diseases such as osteoporosis. Schwann cells (SCs), the primary glial cells of the peripheral nervous system, are recognized to contribute to participating in bone remodeling through interactions with osteoblasts. Nevertheless, their specific function in osteoclasts-mediated bone resorption remains to be fully elucidated. Here, we demonstrate that SCs inhibit osteoclastogenesis in bone homeostasis, primarily through extracellular vesicles (EVs)-mediated activation of PTEN, which in turn negatively regulates the PI3K/AKT signaling pathway, and consequently attenuates the bone resorption process. To promote the targeted delivery and accumulation of EVs in bone tissue, SC-derived EVs (SC-EVs) were engineered with acidic peptides. Subsequent studies in vivo revealed that EVs derived from SCs significantly mitigated bone loss in ovariectomized mice, and bone-targeted EVs exhibited superior efficacy in restoring bone mass. These findings elucidated the neural regulation of bone homeostasis and proposed that SC-EVs, as peripheral nerve-bone crosstalk, could become a novel therapeutic approach for osteoporosis.