Enhanced Osteolysis Targeted Therapy through Fusion of Exosomes Derived from M2 Macrophages and Bone Marrow Mesenchymal Stem Cells: Modulating Macrophage Polarization.

Aseptic loosening of prostheses is a highly researched topic, and wear particle-induced macrophage polarization is a significant cause of peri-prosthetic osteolysis. Exosomes derived from bone marrow mesenchymal stem cells (BMSCs-Exos) promote M2 polarization and inhibit M1 polarization of macrophages. However, clinical application problems such as easy clearance and lack of targeting exist. Exosomes derived from M2 macrophages (M2-Exos) have good biocompatibility, immune escape ability, and natural inflammatory targeting ability. M2-Exos and BMSCs-Exos fused exosomes (M2-BMSCs-Exos) are constructed, which targeted the osteolysis site and exerted the therapeutic effect of both exosomes. M2-BMSCs-Exos achieved targeted osteolysis after intravenous administration inhibiting M1 polarization and promoting M2 polarization to a greater extent at the targeted site, ultimately playing a key role in the prevention and treatment of aseptic loosening of prostheses. In conclusion, M2-BMSCs-Exos can be used as a precise and reliable molecular drug for peri-prosthetic osteolysis. Fused exosomes M2-BMSCs-Exos  were originally proposed and successfully prepared, and exosome fusion technology provides a new theoretical basis and solution for the clinical application of therapeutic exosomes.

Multifunctional fucoidan-loaded Zn-MOF-encapsulated microneedles for MRSA-infected wound healing.

Infected wound healing remains a challenging task in clinical practice due to several factors: (I) drug-resistant infections caused by various pathogens, (II) persistent inflammation that hinders tissue regeneration and (III) the ability of pathogens to persist intracellularly and evade antibiotic treatment. Microneedle patches (MNs), recognized for their effecacious and painless subcutaneous drug delivery, could greatly enhance wound healing if integrated with antibacterial functionality and tissue regenerative potential. A multifunctional agent with subcellular targeting capability and contained novel antibacterial components, upon loading onto MNs, could yield excellent therapeutic effects on wound infections. In this study, we sythesised a zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) loaded with low molecular weight fucoidan (Fu) and further coating by hyaluronic acid (HA), obtained a multifunctional HAZ@Fu NPs, which could hinders Methicillin-resistant Staphylococcus aureus (MRSA) growth and promotes M2 polarization in macrophages. We mixed HAZ@Fu NPs with photocrosslinked gelatin methacryloyl (GelMA) and loaded it into the tips of the MNs (HAZ@Fu MNs), administered to mice model with MRSA-infected full-thickness cutaneous wounds. MNs are able to penetrate the skin barrier, delivering HAZ@Fu NPs into the dermal layer. Since cells within infected tissues extensively express the HA receptor CD44, we also confirmed the HA endows the nanoparticles with the ability to target MRSA in subcellular level. In vitro and in vivo murine studies have demonstrated that MNs are capable of delivering HAZ@Fu NPs deep into the dermal layers. And facilitated by the HA coating, HAZ@Fu NPs could target MRSA surviving at the subcellular level. The effective components, such as zinc ions, Fu, and hyaluronic acid could sustainably released, which contributes to antibacterial activity, mitigates inflammation, promotes epithelial regeneration and fosters neovascularization. Through the RNA sequencing of macrophages post co-culture with HAZ@Fu, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis reveals that the biological functionalities associated with wound healing could potentially be facilitated through the PI3K-Akt pathway. The results indicate that the synergistic application of HAZ@Fu NPs with biodegradable MNs may serve as a significant adjunct in the treatment of infected wounds. The intricate mechanisms driving its biological effects merit further investigation.

Bacterial outer membrane vesicle-cancer cell hybrid membrane-coated nanoparticles for sonodynamic therapy in the treatment of breast cancer bone metastasis.

Breast cancer bone metastasis is a terminal-stage disease and is typically treated with radiotherapy and chemotherapy, which causes severe side effects and limited effectiveness. To improve this, Sonodynamic therapy may be a more safe and effective approach in the future. Bacterial outer membrane vesicles (OMV) have excellent immune-regulating properties, including modulating macrophage polarization, promoting DC cell maturation, and enhancing anti-tumor effects. Combining OMV with Sonodynamic therapy can result in synergetic anti-tumor effects. Therefore, we constructed multifunctional nanoparticles for treating breast cancer bone metastasis. We fused breast cancer cell membranes and bacterial outer membrane vesicles to form a hybrid membrane (HM) and then encapsulated IR780-loaded PLGA with HM to produce the nanoparticles, IR780@PLGA@HM, which had tumor targeting, immune regulating, and Sonodynamic abilities. Experiments showed that the IR780@PLGA@HM nanoparticles had good biocompatibility, effectively targeted to 4T1 tumors, promoted macrophage type I polarization and DC cells activation, strengthened anti-tumor inflammatory factors expression, and presented the ability to effectively kill tumors both in vitro and in vivo, which showed a promising therapeutic effect on breast cancer bone metastasis. Therefore, the nanoparticles we constructed provided a new strategy for effectively treating breast cancer bone metastasis.

PLGA nanoparticles engineering extracellular vesicles from human umbilical cord mesenchymal stem cells ameliorates polyethylene particles induced periprosthetic osteolysis.

The wear particle-induced dissolution of bone around implants is a significant pathological factor in aseptic loosening, and controlling prosthetic aseptic loosening holds crucial social significance. While human umbilical cord mesenchymal stem cell-derived exosomes (HucMSCs-Exos, Exos) have been found to effectively promote osteogenesis and angiogenesis, their role in periprosthetic osteolysis remains unexplored. To enhance their in vivo application, we engineered HucMSCs-Exos-encapsulated poly lactic-co-glycolic acid (PLGA) nanoparticles (PLGA-Exos). In our study, we demonstrate that PLGA-Exos stimulate osteogenic differentiation while inhibiting the generation of reactive oxygen species (ROS) and subsequent osteoclast differentiation in vitro. In vivo imaging revealed that PLGA-Exos released exosomes slowly and maintained a therapeutic concentration. Our in vivo experiments demonstrated that PLGA-Exos effectively suppressed osteolysis induced by polyethylene particles. These findings suggest that PLGA-Exos hold potential as a therapeutic approach for the prevention and treatment of periprosthetic osteolysis. Furthermore, they provide novel insights for the clinical management of osteolysis.

Tranexamic Acid Causes Chondral Injury Through Chondrocytes Apoptosis Induced by Activating Endoplasmic Reticulum Stress.

PURPOSE: To investigate whether tranexamic acid (TXA) is cytotoxic in chondrocyte and cartilage tissues, as well as explore the mechanisms behind the possible toxicity in detail. METHODS: We detected the cell viability of chondrocytes in vitro and the change of morphology and specific in vivo contents of cartilage after TXA treatment. Furthermore, we detected apoptosis in cartilage. We used apoptosis-specific staining, reactive oxygen species detection, mitochondrial membrane potential detection, flow cytometry, and western blot for apoptosis detection. Finally, we detected the activation of endoplasmic reticulum stress (ERS) in TXA-treated chondrocytes to clarify the mechanism behind chondrocyte apoptosis. RESULTS: TXA presented an increasing toxic effect with increasing concentrations, especially in the 100 mg/mL group. In addition, we found that 50 mg/mL and 100 mg/mL TXA significantly increased apoptosis in cartilage and subchondral bone. TXA could induce chondrocyte apoptosis in cell and protein levels with reactive oxygen species generation and mitochondrial membrane depolarization. An apoptosis inhibitor could inhibit the induced apoptosis. Next, TXA induced calcium overload in chondrocytes and increased ERS-specific protein expression, whereas ERS inhibitor blocked ERS activation and further inhibited chondrocyte apoptosis. CONCLUSIONS: We concluded that TXA had a toxic effect on chondrocytes by inducing apoptosis through ERS activation, especially in 50 mg/mL and 100 mg/mL groups. We recommend TXA concentrations of less than 50 mg/mL in joint surgeries. CLINICAL RELEVANCE: It is still unclear whether TXA has a toxic effect on cartilage when topically used in joint surgeries. The concentration also varies. This study provides additional evidence that TXA at high concentrations will cause cartilage damage, which will help to provide a new understanding of the clinical administration of TXA.

Macrophage-derived biomimetic nanoparticles enhanced SDT combined with immunotherapy inhibited tumor growth and metastasis.

Combination therapy based on sonodynamic therapy (SDT) combined with immune checkpoint blockers anti-PD-L1 provides effective anti-tumor effects. We designed a combination therapy based on M1/PLGA@IR780/CAT NPs of SDT-enhanced immunity combined with immune checkpoint blockers against PD-L1, which was based on M1 macrophage membrane-encapsulated poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with the acoustic sensitizer IR780 and catalase (CAT) to successfully realize it. SDT based on M1/PLGA@IR780/CAT NPs could induce tumor cell death by promoting dendritic cell (DC) maturation and modulating the tumor immune microenvironment. In particular, the systemic anti-tumor immune response and potent immune memory induced upon combination with anti-PD-L1 checkpoint blockade not only alleviated the progression of mammary cancer in 4T1 mice and effectively blocked distant metastasis, but also prevented tumor recurrence, providing a promising new therapeutic strategy for clinical tumor therapy.

Targeted therapy for peri-prosthetic osteolysis using macrophage membrane-encapsulated human urine-derived stem cell extracellular vesicles.

Aseptic loosening of the prosthesis is a severe complication after joint replacement. It is of great practical significance and social value to discover the prevention and treatment strategies for this condition. Exosomes from urine-derived stem cells (Exos) have great potential in promoting bone repair, reconstruction, and regulating bone metabolism. However, they are easily eliminated by macrophages and incapable of targeting the osteolysis zone. In this study, based on macrophage "homing" into periprosthetic osteolysis region and cell membrane encapsulating nanotechnology, exosomes from urine-derived stem cells were encapsulated with macrophage membrane (MM) to prevent periprosthetic osteolysis. We found that macrophage membrane encapsulated urine-derived stem cell-derived exosomes (MM-Exos) can be targeted delivery to the osteolysis zone and enhance the therapeutic effectiveness of Exos, which alleviated wear particles-induced calvarial osteolysis. Furthermore, MM-Exos could provide immunological camouflage and allow the Exos to avoid phagocytosis by macrophages and stimulate cellular uptake by bone marrow-derived stem cells (BMSCs). Therefore, we demonstrated the unique ability of the macrophage membrane as a targeted transport of exosomes from urine-derived stem cells for the prevention and treatment of periprosthetic osteolysis. These biomimetic nanoparticles provided a new therapeutic exosome delivery system for preventing wear particles-induced osteolysis. STATEMENT OF SIGNIFICANCE: Macrophage membrane encapsulated urine-derived stem cell-derived exosomes (MM-Exos) can be targeted delivery to the osteolysis zone and enhance the therapeutic effect of Exos on peri­prosthetic osteolysis prevention. MM-Exos could allow the Exos to avoid phagocytosis by macrophages and promote the uptake of Exos by BMSCs.

Bone-targeted ICG/Cyt c@ZZF-8 nanoparticles based on the zeolitic imidazolate framework-8: a new synergistic photodynamic and protein therapy for bone metastasis.

Bone metastasis (BM) is a solid tumor confined to narrow bone marrow cavities with a relatively poor blood supply and hypoxic environment, making conventional anticancer treatments difficult. In our study, we fabricated nanoparticles (NPs) based on zeolitic imidazolate framework-8 (ZIF-8) loaded with indocyanine green (ICG, a photodynamic agent) and cytochrome c (Cyt c, an anticancer protein) with a surface modified by zoledronate (ZOL, a bone-targeting moiety) and a polyvinyl pyrrolidone (PVP) coating to increase their stability. The ICG/Cyt c@ZZF-8 NPs were expected to have synergistic antitumor therapy and bone protection efficiency. The in vitro and in vivo experiments showed the bone-targeted and pH-sensitive ability of ICG/Cyt c@ZZF-8 NPs, which could be engulfed by tumor cells and release the cargos. Upon 780 nm laser irradiation, ICG produces cytotoxic reactive oxygen species (ROS, 1O2) that directly kill tumor cells, and Cyt c with catalase-like activity can induce programmed cell death and decompose H2O2 to O2, thus enhancing the PDT efficiency. The ZOL can further inhibit bone resorption. The ICG/Cyt c@ZZF-8 NPs showed improved antitumor and bone protection efficiency in a mouse model of BM. This study demonstrated a potential mode for the synergetic therapy of orthopedic diseases.