Prevention And Therapeutic Effect Of Exosomes From Human Urine-derived Stem Cells Encapsulated Into PLGA Nanoparticles On Particulate Polyethylene-induced Osteolysis In Mice

Part one Exosomes from human urine-derived stem cells ameliorate particulate polyethylene-induced osteolysisBackground: Wear particle-induced periprosthetic osteolysis is a common long-term complication of total joint arthroplasty and represents the major cause of aseptic loosening and subsequent implant failure.Currently,there are no effective therapeutic options to prevent osteolysis from occurring and often need revision surgery.Exosomes are important nano-sized paracrine mediators of intercellular communications and can be directly utilized as therapeutic agents for tissue repair and regeneration.Here,we explored the therapeutic potential of exosomes from human urine-derived stem cells(USC-Exos)in preventing wear particle-induced osteolysis.Methods: USCs were characterized by flow cytometry and multiple differentiation potential.The impact of USC-Exos on osteoblastic differentiation of bone marrow mesenchymal stem cells(BMSCs)and osteoclastogenesis of RAW264.7 cells were verified in vitro.The effects of USC-Exos on ultra-high molecular weight PE(UHMWPE)-induced murine calvarial osteolysis model were tested to evaluate bone mass,inflammation,osteogenic and osteoclastic activities.Results: USCs were positive for CD44,CD73,CD29 and CD90,but negative for CD34 and CD45.USCs were able to differentiate into osteogenic,chondrogenic,and adipogenic cells.USC-Exos exhibited a round-shaped morphology with a double-layered membrane structure and positive for CD63 and TSG101,negative for Calnexin.In vitro,USC-Exos could promote the osteogenic differentiation of BMSCs,reduces the production of proinflammatory factors in macrophages and suppresses their osteoclastic abilities.In vivo,injection of USC-Exos into the center of the calvariae caused less inflammatory cytokine generation and less osteolysis compared to control and significantly enhanced the bone formation.Conclusions: Our findings demonstrate that USC-Exos can prevent UHMWPE-induced osteolysis by inciting less inflammatory,inhibiting bone resorption and stimulating bone formation.Part two Exosomes from Human Urine-derived Stem Cells Encapsulated into PLGA Nanoparticles for Therapy in Mice with Particulate Polyethylene-induced OsteolysisBackground: Exosomes are key mediators of cell-cell communication and can be directly utilized as therapeutic agents for tissue repair and regeneration.Here,we fabricated a nanoparticle that carries the exosomes from human urine-derived stem cells(USC-Exos)and explored the effects on polyethylene-induced osteolysis.Methods: USC-Exos derived nanoparticles(NPs-Exos)was fabricated using PLGA solution.The obtained NPs-Exos were deeply characterized to evaluate their characterization,stability,toxicity,the exosome release analysis and the cell uptake study.Then these NPs-Exos were implanted to the murine air pouch model and evaluated their effects on polyethylene-induced osteolysis.Results: The average particle diameter of NPs-Exos was about282±0.4nm,and the Zeta potential was-2.02±0.03 m V.NPs-Exos were stable after long-term storage at room temperature and 4℃ without significant coaggregation.In vitro release profiles indicated sustained release of exosomes for 12 days.In vivo,injection of NPs-Exos into the murine air pouch caused less osteolysis compared to USC-Exos group and NPs-Exos significantly reduced the bone absorption,as gauged by histology and Micro-CT scanning.Conclusions: Our findings suggest that USC-Exos inspired PLGA nanoparticles can prevent particulate polyethylene-induced osteolysis and bone loss and may represent a promising strategy for aseptic loosening of prostheses.