Engineering of dendritic cell bispecific extracellular vesicles for tumor-targeting immunotherapy.

Advances in the development of therapeutic extracellular vesicles (EVs) for cancer immunotherapy have allowed them to emerge as an alternative to cell therapy. In this proof-of-concept work, we develop bispecific EVs (BsEVs) by genetically engineering EV-producing dendritic cells (DCs) with aCD19 scFv and PD1 for targeting tumor antigens and blocking immune checkpoint proteins simultaneously. We find that these bispecific EVs (EVs-PD1-aCD19) have an impressive ability to accumulate in huCD19-expressing solid tumors following intravenous injection. In addition, EVs-PD1-aCD19 can remarkably reverse the immune landscape of the solid tumor by blocking PD-L1. Furthermore, EVs-PD1-aCD19 can also target tumor-derived EVs in circulation, which prevents the formation of a premetastatic niche in other tissues. Our technology is a demonstration of bispecific EV-based cancer immunotherapy, which may inspire treatments against various types of tumors with different surface antigens and even a patient-tailored therapy.

Degradation-resistant implanted biomaterials establish an immunosuppressive microenvironment that induces T cell exhaustion by recruiting myeloid cells.

Implanted biomaterials have transformed healthcare and the treatment of injury and disease, but their influence on the local immune landscape remains unclear. Here we discovered that degradation-resistant titanium-based implants establish an immunosuppressive microenvironment by recruiting myeloid cells, including monocytes, macrophages, neutrophils, and myeloid-lineage dendritic cells. Unlike normal tissues, the tissues nearby implants exhibit an chronic inflamed and immunosuppressive status characterised by myeloid-rich, T cell-exhaustion gene signature by single-cell RNA sequencing. Vitamin C treatment provides an effective strategy to rescue the immunosuppressive microenvironment, which can be used as a regular supplement to reduce the risk of malignant cell survival around the implants.

Bioadhesive injectable hydrogel with phenolic carbon quantum dot supported Pd single atom nanozymes as a localized immunomodulation niche for cancer catalytic immunotherapy.

Immunotherapy is a powerful way to treat cancer, however, systemic treatment-associated adverse effects remain a major concern. In this study, a bioadhesive injectable hydrogel is developed to provide localized immune niches for tumor microenvironment immunomodulation and cancer catalytic immunotherapy. First, a phenolic single atom nanozyme (SAN) was developed by in situ synthesis of Pd single atom on catechol-grafted carbon-quantum-dot (DA-CQD@Pd) templates. Then, the bioadhesive injectable hydrogel consisting of DA-CQD@Pd SAN and immune adjuvant CpGODN was formed through SAN-catalyzed free-radical polymerization. The SAN exhibited peroxidase-like activity to generate ROS and kill tumor cells through catalytic therapy. The hydrogel locally released CpGODN in a sustained manner, which limited the risk of systemic exposure, reducing the impact of CpGODN toxicity, and protecting CpGODN from degradation. The bioadhesive hydrogel immobilized around solid tumor to provide an immune response site after injection. When combined it with the administration of immune checkpoint inhibitor anti-PD-L1, the hydrogel realized localized immunomodulation, maximized therapeutic efficacy and prevents tumor metastasis via a catalytic immunotherapy.

Genetically Engineered Hematopoietic Stem Cells Deliver TGF-ß Inhibitor to Enhance Bone Metastases Immunotherapy.

Owing to the immune microenvironment of bones and low selectivity of the drug, patients with bone metastases often respond poorly to immunotherapy. In this study, programmed cell death protein 1 (PD1)-expressing hematopoietic stem cells (HSCs) are genetically engineered for bone-targeted delivery of the transforming growth factor beta (TGF-ß) small-molecule inhibitor SB-505124 (SB@HSCs-PD-1). Intriguingly, compared to anti-PD-L1 monoclonal antibodies, as "living drugs", HSCs-PD-1 not only show great targeting ability to the bone marrow, but are also able to reduplicate themselves within the bone marrow niche and continuously express PD-1 molecules. The SB released from HSCs-PD-1 competitively bound to TGF-ß receptors on CD4+ T cells and facilitate CD4+ T cell differentiation to helper T (TH )1 and TH 2 cells, thereby reprogramming the local immunosuppressive milieu of the bone marrow. Additionally, HSCs-PD-1 can block programmed death-ligand 1 on tumor and myeloid cells, resulting in reinvigorated anti-tumor immunity of T cells. In conclusion, in the present study, an alternative cell engineering strategy is delineated for immune checkpoint blockade therapy, to target bone metastasis using HSCs as a platform, which shows great promise in the treatment of bone metastases.

Mesenchymal Stem Cell-Derived Extracellular Vesicles with High PD-L1 Expression for Autoimmune Diseases Treatment.

Autoimmune diseases are the third most common disease influencing the quality of life of many patients. Here, a programmed cell death-ligand 1 + (PD-L1) mesenchymal stem cell (MSC) derived extracellular vesicles (MSC-sEVs-PD-L1) using lentivirus-mediated gene transfection technology is developed for reconfiguration of the local immune microenvironment of affected tissue in autoimmune diseases. MSC-sEVs-PD-L1 exhibits an impressive ability to regulate various activated immune cells to an immunosuppressed state in vitro. More importantly, in dextran sulfate sodium-induced ulcerative colitis (UC) and imiquimod-induced psoriasis mouse models, a significantly high accumulation of MSC-sEVs-PD-L1 is observed in the inflamed tissues compared to the PD-L1+ MSCs. Therapeutic efficiency in both UC and psoriasis mouse disease models is demonstrated using MSC-sEVs-PD-L1 to reshape the inflammatory ecosystem in the local immune context. A technology is developed using MSC-sEVs-PD-L1 as a natural delivery platform for autoimmune diseases treatment with high clinical potential.

Yeast-derived nanoparticles remodel the immunosuppressive microenvironment in tumor and tumor-draining lymph nodes to suppress tumor growth.

Microbe-based cancer immunotherapy has recently emerged as a hot topic for cancer treatment. However, serious limitations remain including infection associated side-effect and unsatisfactory outcomes in clinic trials. Here, we fabricate different sizes of nano-formulations derived from yeast cell wall (YCW NPs) by differential centrifugation. The induction of anticancer immunity of our formulations appears to inversely correlate with their size due to the ability to accumulate in tumor-draining lymph node (TDLN). Moreover, we use a percolation model to explain their distribution behavior toward TDLN. The abundance and functional orientation of each effector component are significantly improved not only in the microenvironment in tumor but also in the TDLN following small size YCW NPs treatment. In combination with programmed death-ligand 1 (PD-L1) blockade, we demonstrate anticancer efficiency in melanoma-challenged mice. We delineate potential strategy to target immunosuppressive microenvironment by microbe-based nanoparticles and highlight the role of size effect in microbe-based immune therapeutics.

Physiologically triggered injectable red blood cell-based gel for tumor photoablation and enhanced cancer immunotherapy.

Hydrogels are widely used for drug delivery and tissue engineering. Here we developed a simple injectable red blood cells (RBCs)-based gel for cancer photo-immunotherapy. We find that subcutaneous injected homologous RBCs could form hydrogel-like composition in mice, due to the infiltrated platelets and thrombin under physiological environment. In addition, the formed RBC-gel has photothermal effect under NIR laser exposure on account of deep reddish color. In mice bearing CT26 tumors, we demonstrate photo-immunotherapy of cancer by local injection of imiquimod (R837) adjuvant engineered RBCs. The photothermal effect of the in situ formed RBC-gel effectively burns tumor to release tumor-associated antigens (TAAs), promotes the release of R837 from RBCs to the tumor draining lymph node, thereby activating the lymph node-resident antigen-presenting cells (APCs) remarkably. A durable systemic immune response is induced following the combination treatment of the primary tumor. 100% mice rejected tumor rechallenge and are survived at least 250 days without any detectable tumors. Our strategy highlights the RBCs, the most common type of cell in our blood, as the hydrogel for drug delivery and cancer photo-immunotherapy.

Targeted delivery of dexamethasone in acute pneumonia.

Pneumonia has contributed to significant mortality owing to the irreversible injury to the lungs and severe inflammation of the tissue. Dexamethasone (DEX) is regarded as an effective drug to relieve the level of pneumonia, while the adverse effect of which is non-negligible. Here, we developed a targeted delivery strategy based on platelet-derived extracellular vesicles (PEVs), which are naturally occurring nanoparticles released by platelets, for DEX delivery in acute pneumonia, aiming to reduce the side effects and improve the therapeutic efficacy. Our strategy may shed light on the problems in DEX-based acute pneumonia therapy clinically.

Implantable blood clot loaded with BMP-2 for regulation of osteoimmunology and enhancement of bone repair.

The treatment of large-area bone defects still faces many difficulties and challenges. Here, we developed a blood clot delivery platform loaded with BMP-2 protein (BMP-2@BC) for enhanced bone regeneration. Blood clot gel platform as natural biomaterials can be engineered from autologous blood. Once implanted into the large bone defect site, it can be used for BMP-2 local delivery, as well as modulating osteoimmunology by recruiting a great number of macrophages and regulating their polarization at different stages. Moreover, due to the deep-red color of blood clot gel, mild localized hyperthermia under laser irradiation further accelerated bone repair and regeneration. We find that the immune niche within the bone defect microenvironment can be modulated in a controllable manner by the blood clots implantation and laser treatment. We further demonstrate that the newly formed bone covered almost 95% of the skull defect area by our strategy in both mice and rat disease models. Due to the great biocompatibility, photothermal potential, and osteoimmunomodulation capacity, such technology shows great promise to be used in further clinical translation.

3D Printing Scaffold Vaccine for Antitumor Immunity.

Cancer vaccine platform has attracted great interest in the field of cancer immunotherapy. Here, 3D printed scaffolds loaded with immunoregulators are developed for enhanced cancer immunotherapy. The rapid manufacturing and precise molding based on 3D printing can realize the mass manufacturing of cancer vaccines and personalized design. Meanwhile, compared to the traditional hydrogel, the 3D-scaffold with porous structure endows its similar functions compared with real lymphoid organs by recruitment of a great number of immune cells, leading to the formation of "artificial tertiary lymphoid structures," where there is a promising site to enhance both humoral and cellular immune responses. Efficient anticancer immunity is induced when combined with immune checkpoint blockade to inhibit the tumor growth. Personalized antitumor scaffold vaccines are further demonstrated for filling of tumor site after surgery to prevent cancer metastasis. Taken together, these results promise the 3D printing scaffold vaccine as the potential strategy for cancer vaccine therapy in the future.

Immunosuppressive Nanoparticles for Management of Immune-Related Adverse Events in Liver.

Immune checkpoint blockade (ICB) therapy has been considered as an effective way to boost immune cells to recognize and attack tumors. However, side effects known as immune-related adverse events (irAEs) should be carefully managed. Here, we engineer immunosuppressive nanoparticles by coating PD-L1 overexpressed mesenchymal stem cells (MSCs) plasma membrane on poly lactic-co-glycolic acid nanoparticles (MSC-PD-L1+ NPs) for managing and reducing irAEs induced by immune checkpoint inhibitors. The nanoparticles can enrich at liver site after intravenous administration. In the high dose of anti-PD-L1 mAb-induced irAEs clinically relevant mouse model, a low dose of MSC-PD-L1+ NPs (2 mg/kg) sufficiently rescues hepatitis by inactivating T cells and macrophages in the liver tissue. More intriguingly, due to the dose threshold for nanoparticles to the tumor site, we unexpectedly find that the injected NPs do not affect the efficiency of ICB therapy to inhibit solid tumor growth. Such a strategy shows potential for managing the various cancer immunotherapy associated irAEs in clinical applications.

Injectable Erythrocyte Gel Loaded with Bulleyaconitine A for the Treatment of Rheumatoid Arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease with clinical manifestations including joint cartilage, synovitis, and bone damage. Here we developed an injectable erythrocyte gel loaded with Bulleyaconitine A (BLA) for the treatment of RA and demonstrated its anti-inflammatory effects in vivo and in vitro. In vitro experiments showed that BLA could effectively down-regulate the expression of pro-inflammatory factor in activated macrophages through the nuclear factor-κB (NF-κB) pathway. In vivo experiments have shown that the injection of BLA@RBCs in the inflammatory joints of CIA mice increases the local concentration of BLA in a long time. Improved therapeutic outcomes and reduced toxicity of BLA are demonstrated in our work. Together, the developed BLA@RBCs drug delivery system provides an alternative strategy to treat RA joints and shows high potential in clinical RA treatment.

An implantable blood clot-based immune niche for enhanced cancer vaccination.

Cancer immunotherapy using cancer vaccines has shown great potential in the prevention and treatment of cancer. Here, we report an implantable autologous blood clot scaffold for enhanced cancer vaccination. It comprises a gel-like fibrin network formed by coagulation of blood to trap a large number of red blood cells. Upon implantation, the cross-linked RBCs in the blood clot can attract and recruit a great number of immune cells, leading to the formation of an "immune niche." Encapsulated with tumor-associated antigen and adjuvant, the blood clot vaccine (BCV) can induce a robust anticancer immune response. The BCV combined with immune checkpoint blockade effectively inhibits tumor growth in B16F10 and 4T1 tumor models. The proposed implantable blood clot cancer vaccine can be readily made by mixing the blood from patients with cancer with immunomodulating agents ex vivo, followed by reimplantation into the same patient for personalized cancer immunotherapy in future clinical translation.