Ancient Medicinal Insect Steleophaga Plancyi (Boleny)-Derived Extracellular Vesicle-Like Particles Enhances Autophagic Activity to Promote Osteogenic Differentiation via Melatonin in Osteoporosis

Introduction: (SP), a component of traditional Chinese medicine, is known to enhance bone health, but the molecular mechanisms behind its osteoprotective effects are not well understood. Methods: We isolated extracellular vesicle (EV)-like particles from SP (SP-EVLP) using differential velocity centrifugation and investigated their effects on human bone marrow stromal cells (hBMSCs) in vitro. We utilized CCK-8, Alkaline phosphatase (ALP) and alizarin red staining (ARS), RNA-seq, bioinformatics, immunofluorescence, and Western blot to elucidate the osteoprotective role and mechanisms of SP-EVLP. The therapeutic potential of SP-EVLP was evaluated in an ovariectomized (OVX) rat model, a standard model for osteoporosis, by encapsulating them in enteric-coated capsules. Results: SP-EVLP were successfully isolated and characterized, and they were shown to be effectively internalized by hBMSCs, enhancing osteogenic differentiation. In the OVX rat model, SP-EVLP encapsulated in enteric-coated capsules significantly increased bone mass, indicating a robust osteoprotective effect. Further mechanistic studies revealed that SP-EVLP promotes osteoblast proliferation by activating melatonin-induced autophagy, a pathway that may improve osteoporotic conditions. Conclusion: Our results establish SP-EVLP as a promising therapeutic candidate for osteoporosis. The activation of melatonin-induced autophagy by SP-EVLP suggests a molecular mechanism for its osteoprotective effects, opening new possibilities for osteoporosis treatment development.