Bioorthogonal targeted cell membrane vesicles/cell-sheet composites reduce postoperative tumor recurrence and scar formation of melanoma.

While surgical resection is the predominant clinical strategy in the treatment of melanoma, postoperative recurrence and undetectable metastasis are both pernicious drawbacks to this otherwise highly successful approach. Furthermore, the deep cavities result from tumor excision can leave long lasting wounds which are slow to heal and often leave visible scars. These unmet needs are addressed in the present work through the use of a multidimensional strategy, and also promotes wound healing and scar reduction. In the first phase, cell membrane-derived nanovesicles (NVs) are engineered to show PD-1 and dibenzocyclooctyne (DBCO). These are capable of reactivating T cells by blocking the PD-1/PD-L1 pathway. In the second phase, azido (N3) labeled mesenchymal stem cells (MSCs) are cultured into cell sheets using tissue engineering, then apply directly to surgical wounds to enhance tissue repair. Owing to the complementary association between DBCO and N3 groups, PD-1 NVs were accumulated at the site of excision. This strategy can inhibit postoperative tumor recurrence and metastasis, whilst also promoting wound healing and reducing scar formation. The results of this study set a precedent for a new and innovative multidimensional therapeutic strategy in the postoperative treatment of melanoma.

Fe3+-binding transferrin nanovesicles encapsulating sorafenib induce ferroptosis in hepatocellular carcinoma.

BACKGROUND: Ferroptosis, iron-dependent cell death, is an established mechanism for cancer suppression, particularly in hepatocellular carcinoma (HCC). Sorafenib (SOR), a frontline drug for the treatment of HCC, induces ferroptosis by inhibiting the Solute Carrier family 7 member 11 (SLC7A11), with inadequate ferroptosis notably contributing to SOR resistance in tumor cells. METHODS: To further verify the biological targets associated with ferroptosis in HCC, an analysis of the Cancer Genome Atlas (TCGA) database was performed to find a significant co-upregulation of SLC7A11 and transferrin receptor (TFRC), Herein, cell membrane-derived transferrin nanovesicles (TF NVs) coupled with Fe3+ and encapsulated SOR (SOR@TF-Fe3+ NVs) were established to synergistically promote ferroptosis, which promoted the iron transport metabolism by TFRC/TF-Fe3+ and enhanced SOR efficacy by inhibiting the SLC7A11. RESULTS: In vivo and in vitro experiments revealed that SOR@TF-Fe3+ NVs predominantly accumulate in the liver, and specifically targeted HCC cells overexpressing TFRC. Various tests demonstrated SOR@TF-Fe3+ NVs accelerated Fe3+ absorption and transformation in HCC cells. Importantly, SOR@TF-Fe3+ NVs were more effective in promoting the accumulation of lipid peroxides (LPO), inhibiting tumor proliferation, and prolonging survival rates in HCC mouse model than SOR and TF- Fe3+ NVs alone. CONCLUSIONS: The present work provides a promising therapeutic strategy for the targeted treatment of HCC.

TNF-R1 Cellular Nanovesicles Loaded on the Thermosensitive F-127 Hydrogel Enhance the Repair of Scalded Skin.

Excessive inflammatory response after severe scalding is an important cause of delayed wound healing and is even life-threatening. Tumor necrosis factor α (TNF-α) is a key pro-inflammatory factor of skin trauma. Interacting with tumor necrosis factor receptor 1 (TNF-R1), TNF-α causes excessive inflammation and poor prognosis by activating NF-κB pathway. Antagonizing high levels of TNF-α is one of the therapeutic approaches for diseases associated with the overactivation of inflammatory responses. However, the available monoclonal antibodies are limited in their application due to their complex preparation process, high price, and the lack of cell targeting ability leading to systemic toxicity and side effects. In this study, by using a genetic bioengineering technique, we modified TNF-R1 on the cell membrane surface-derived nanovesicles (NVs). We confirmed that TNF-R1 NVs stably expressed TNF-R1 on the membrane surface and interacted with its ligand TNF-α. Furthermore, TNF-R1 NVs competitively antagonized the effect of TNF-α in the wound healing assay in vitro. In the scalded mouse model, TNF-R1 NVs were released continuously from the thermosensitive hydrogel Pluronic F-127, resulting in less inflammation and better wound healing. Our results revealed TNF-R1 NVs as promising cell-free therapeutic agents in alleviating TNF-α-mediated pro-inflammatory signaling and promoting wound repair.

Engineering PD-L1 Cellular Nanovesicles Encapsulating Epidermal Growth Factor for Deep Second-Degree Scald Treatment.

Scars are common and intractable consequences after scalded wound healing, while monotherapy of epidermal growth factors does not solve this problem. Maintaining the stability of epidermal growth factors and promoting scarless healing of wounds is paramount. In this study, engineering cellular nanovesicles overexpressing PD-L1 proteins, biomimetic nanocarriers with immunosuppressive efficacy, were successfully prepared to encapsulate epidermal growth factors for maintaining its bioactivity. Remarkably, PD-L1 cellular nanovesicles encapsulating epidermal growth factors (EGF@PDL1 NVs) exerted desired therapeutic effect by attenuating the overactivation of T cell immune response and promoting skin cells migration and proliferation. Hence, EGF@PD-L1 NVs promoted wound healing and prevented scarring in deep second-degree scald treatment, demonstrating a better effect than using individual PD-L1 NVs or EGF. This research proved that EGF@PD-L1 NVs is considered an innovative and thorough therapy of deep second-degree scald.

Exosomal Vimentin from Adipocyte Progenitors Protects Fibroblasts against Osmotic Stress and Inhibits Apoptosis to Enhance Wound Healing.

Mechanical stress following injury regulates the quality and speed of wound healing. Improper mechanotransduction can lead to impaired wound healing and scar formation. Vimentin intermediate filaments control fibroblasts' response to mechanical stress and lack of vimentin makes cells significantly vulnerable to environmental stress. We previously reported the involvement of exosomal vimentin in mediating wound healing. Here we performed in vitro and in vivo experiments to explore the effect of wide-type and vimentin knockout exosomes in accelerating wound healing under osmotic stress condition. Our results showed that osmotic stress increases the size and enhances the release of exosomes. Furthermore, our findings revealed that exosomal vimentin enhances wound healing by protecting fibroblasts against osmotic stress and inhibiting stress-induced apoptosis. These data suggest that exosomes could be considered either as a stress modifier to restore the osmotic balance or as a conveyer of stress to induce osmotic stress-driven conditions.

PD-L1 cellular nanovesicles carrying rapamycin inhibit alloimmune responses in transplantation.

Organ transplantation has been employed upon serious injuries, but a T-cell-mediated potent inflammatory immune response often leads to graft rejection. Immunosuppressive drugs such as rapamycin (RAPA) have to be taken after organ transplantation, but long-term use of these drugs causes severe adverse effects. Immune checkpoint pathways such as the programmed death-receptor 1/programmed death-ligand 1 (PD-1/PD-L1) provides an immunosuppressive environment, preventing excessive tissue destruction due to inflammatory immune responses. In this study, we bioengineered cell membrane-derived PD-L1 nanovesicles (PD-L1 NVs) to carry low doses of RAPA. These NVs inhibited T-cell activation and proliferation in vitro, by enhancing the PD-1/PD-L1 immune co-inhibitory signaling axis and inhibiting the mTOR pathway. Importantly, PD-L1 NVs encapsulated with rapamycin exerted stronger effects on inhibiting T-cell proliferation than PD-L1 NVs or rapamycin alone. This can be recapitulated in a mouse skin transplantation model, leading to the weakened alloimmune response and allograft tolerance. We also found that PD-L1/rapamycin vesicles have additional function to induce regulatory T cells in the recipient spleens. Our study highlighted the power of combining low-dose rapamycin and PD-L1 in the nanovesicles as immunosuppressants to promote allograft acceptance.