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.

PD-1 Cellular Nanovesicles Carrying Gemcitabine to Inhibit the Proliferation of Triple Negative Breast Cancer Cell.

PD-1 inhibitor Keytruda combined with chemotherapy for Triple-negative breast cancer (TNBC) has been approved for FDA, successfully representing the combination therapy of immunotherapy and chemotherapy for the first time in 2020. However, PD-L1 inhibitor Tecentriq combined with albumin paclitaxel using the similar strategy failed to achieve the expected effect. Therefore, it is still necessary to explore new effective immunotherapy and chemotherapy-based combined strategies. We developed a cell membrane-derived programmed death-ligand 1(PD-1) nanovesicle to encapsulate low-dose gemcitabine (PD-1&GEM NVs) to study the effect on breast cancer in vitro and in vivo. We found that engineered PD-1&GEM NVs could synergistically inhibit the proliferation of triple-negative breast cancer, which interacted with PD-L1 in triple-negative breast cancer to disrupt the PD-L1/PD-1 immune inhibitory axis and promoted cancer cell apoptosis. Moreover, PD-1&GEM NVs had better tumor targeting ability for PD-L1 highly-expressed TNBC cells, contributing to increasing the drug effectiveness and reducing toxicity. Importantly, gemcitabine-encapsulated PD-1 NVs exerted stronger effects on promoting apoptosis of tumor cells, increasing infiltrated CD8+ T cell activation, delaying the tumor growth and prolonging the survival of tumor-bearing mice than PD-1 NVs or gemcitabine alone. Thus, our study highlighted the power of combined low-dose gemcitabine and PD-1 in the nanovesicles as treatment to treat triple-negative breast cancer.

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.

Engineering Programmed Death Ligand-1/Cytotoxic T-Lymphocyte-Associated Antigen-4 Dual-Targeting Nanovesicles for Immunosuppressive Therapy in Transplantation.

T cell activation by immune allorecognition is a major contributing factor toward the triggering of organ rejection. Immunosuppressive drugs have to be taken after organ transplantation, but long-term use of these drugs increases the risks of infection and other serious disorders. Here, we showed dysregulation of programmed cell death-ligand 1/programmed cell death 1 (PD-L1/PD-1) and cytotoxic T-lymphocyte-associated protein 4/cluster of differentiation 80 (CTLA-4/CD80) in the spleen of two organ transplantation models. Using a bioengineering approach, cellular exosome-like nanovesicles (NVs) displaying PD-L1/CTLA-4 dual-targeting cargos were designed, and their specificity to bind their ligands PD-1 and CD80 on T cell and dendritic cell surfaces was confirmed. These NVs consequently enhanced PD-L1/PD-1 and CTLA-4/CD80 immune inhibitory pathways, two key immune checkpoints to co-inhibit T cell activation and maintain peripheral tolerance. It was also confirmed that PD-L1/CTLA-4 NVs led to the reduction of T cell activation and proliferation in vitro and in vivo. Finally, it was demonstrated that PD-L1/CTLA-4 NVs reduced density of CD8+ T cells and cytokine production, enriched regulatory T cells, and prolonged the survival of mouse skin and heart grafts. Taken together, these data supported the idea that PD-L1/CTLA-4 dual-targeting NVs exert immune inhibitory effects and may be used as a prospective immunosuppressant in organ transplantation.

Rapid Method for Detection of Staphylococcus aureus in Feces.

Staphylococcus aureus is an opportunistic human pathogen causing food-borne diseases. Therefore, the goal of the present work was to develop a robust protocol for identification of small amounts of S. aureus DNA in order to establish a rapid, sensitive, and simple method of detect whether this species is present in the stool of patients. A protocol was developed for extraction of DNA by Fe3O4 @SiO2 microbeads and subsequent detection of S. aureus-specific DNA sequences by the loop-mediated isothermal amplification (LAMP). The LAMP technique was rapid and sensitive, which allowsed the detect for bacteria at concentrations as low as 10² cells/mL. This level of detection was superior to that seen for conventional PCR and real-time PCR. Moreover, the LAMP protocol did not require specialized expensive instrumentation. These features of the novel assay developed here indicate that it may serve as an effective tool for point-of-care diagnosis of acute S. aureus infections.

Spongy bilayer dressing composed of chitosan-Ag nanoparticles and chitosan-Bletilla striata polysaccharide for wound healing applications.

The purpose of this study was to develop a promising wound dressing. Though chitosan cross-linked with genipin has been widely used as biomaterials, with the addition of partially oxidized Bletilla striata polysaccharide, the newly developed material in this study (coded as CSGB) showed less gelling time, more uniform aperture distribution, higher water retention, demanded mechanical strength and more L929 cell proliferation compared to the chitosan cross-linked only with genipin. Owning to partial blocking of free amino groups of chitosan, CSGB revealed almost no antibacterial activities, thus the bilayer composite of chitosan-silver nanoparticles (CS-AgG) on CSGB was designed to inhibit microbial invasion. The in vivo studies indicated that both CSGB and bilayer wound dressing significantly accelerated the healing rate of cutaneous wounds in mice, and the bilayer exhibited better mature epidermization with less inflammatory cells on Day 7. Therefore, this novel bilayer composite has great potential in wound dressing applications.