A Printable Hydrogel Loaded with Medicinal Plant Extract for Promoting Wound Healing.

How to promote wound healing is still a major challenge in the healthcare while macrophages are a critical component of the healing process. Compared to various bioactive drugs, many plants have been reported to facilitate the wound healing process by regulating the immune response of wounds. In this work, a Three-dimensional (3D) printed hydrogel scaffold loaded with natural Centella asiatica extract (CA extract) is developed for wound healing. This CA@3D scaffold uses gelatin (Gel) and sodium alginate (SA) with CA extract as bio-ink for 3D printing. The CA extract contains a variety of bioactive compounds that make the various active ingredients in Centella asiatica work in concert. The printed CA@3D scaffold can fit the shape of wound, orchestrate the macrophages and immune responses within the wound, and promote wound healing compared to commercial wound dressings. The underlying mechanism of promoting wound healing is also illuminated by applying multi-omic analyses. Moreover, the CA extract loaded 3D scaffold also showed great ability to promote wound healing in diabetic chronic wounds. Due to its ease of preparation, low-cost, biosafety, and therapeutic outcomes, this work proposes an effective strategy for promoting chronic wound healing.

Neurological disorders after severe pneumonia are associated with translocation of endogenous bacteria from the lung to the brain.

Neurological disorders are a common feature in patients who recover from severe acute pneumonia. However, the underlying mechanisms remain poorly understood. Here, we show that the neurological syndromes after severe acute pneumonia are partly attributed to the translocation of endogenous bacteria from the lung to the brain during pneumonia. Using principal components analysis, similarities were found between the brain's flora species and those of the lungs, indicating that the bacteria detected in the brain may originate from the lungs. We also observed impairment of both the lung-blood and brain-blood barriers, allowing endogenous lung bacteria to invade the brain during pneumonia. An elevated microglia and astrocyte activation signature via bacterial infection-related pathways was observed, indicating a bacterial-induced disruption of brain homeostasis. Collectively, we identify endogenous lung bacteria that play a role in altering brain homeostasis, which provides insight into the mechanism of neurological syndromes after severe pneumonia.

PD-L1-Expressing Extracellular Vesicles for the Treatment of Pneumonia.

Acute respiratory distress syndrome (ARDS) is a severe lung condition with a high mortality rate and a lack of effective drug therapy. In this work, we developed mesenchymal stem cell (MSC)-derived extracellular vesicles with high PD-L1 expression (MSC-EVs-PD-L1) for treating lipopolysaccharide (LPS)-induced pneumonia by intratracheal administration. We found an upregulation of PD-1 expression in the inflammatory region of murine lungs; hence, MSC-EVs-PD-L1 exerted immunosuppressive effects via the PD-1/PD-L1 signaling pathway. Furthermore, we treated LPS-induced pneumonia mice by intratracheal administration, which enabled heavy drug accumulation in the lungs of mice and better therapeutic efficacy compared to systemic administration. Our results suggest that MSC-EVs-PD-L1 has the potential to provide a universal platform technology for the immunotherapy of pneumonia.

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.

Severe pneumonia induces immunosenescence of T cells in the lung of mice.

Severe pneumonia may induce sequelae and accelerated aging process even after the person has recovered. However, the underline mechanism is not very clear. More research is needed to fully understand the long-term effects of severe pneumonia. In this study, we found that mice recovered from severe pneumonia showed lung immunosenescence, which was characterized by a bias naive-memory balance of T lymphocytes in the lung. The reduction of naïve T cells is associated with the diminished immune response to cancer or external new antigens, which is one of the key changes that occurs with age. Our results also indicate the link between severe pneumonia and aging process, which is mediated by the disrupted T cells homeostasis in the lungs after pneumonia.

Nanoplastics Shape Adaptive Anticancer Immunity in the Colon in Mice.

The impact of nanoplastics (NPs) on human health is still not well understood, and more research is needed to better understand the risks associated with these particles. In this study, we found that oral administration of polyethylene (PE) NPs in a mice model significantly disrupted the intestinal microenvironment, which shapes adaptive immune response and favors the established in situ colorectal tumor growth. Using single-cell RNA sequencing technology, we show that NPs triggered colon IL-1ß-producing macrophages by inducing lysosome damage, leading to colonic Treg and Th17 differentiation associated with T cell exhaustion, which creates a colon environment that favors the tumor initiation and progress. A similar effect is also observed in polystyrene NPs. Our result provides insight into the potential link between NPs ingestion and colon tumorigenesis, and the urgency of addressing plastic pollution worldwide.

Oral feeding of nanoplastics affects brain function of mice by inducing macrophage IL-1 signal in the intestine.

Nanoplastics (NPs) as contaminants in food and water have drawn increasing public attention. However, little is known about how NPs shape the gut immune landscape after injection. In this study, we fabricate NPs (∼500 nm) and microplastics (MPs) (∼2 µm) and evaluate their in vivo effects by feeding them to mice. The results suggest that NPs show a better ability to induce gut macrophage activation than MPs. In addition, NPs trigger gut interleukin-1 (IL-1)-producing macrophage reprogramming via inducing lysosomal damage. More importantly, IL-1 signaling from the intestine can affect brain immunity, leading to microglial activation and Th17 differentiation, all of which correlates with a decline in cognitive and short-term memory in NP-fed mice. Thus, this study provides insight into the mechanism of action of the gut-brain axis, delineates the way NPs reduce brain function, and highlights the importance of fixing the plastic pollution problem worldwide.

SnSe Nanosheets Mimic Lactate Dehydrogenase to Reverse Tumor Acid Microenvironment Metabolism for Enhancement of Tumor Therapy.

The acidic tumor microenvironment (TME) is unfriendly to the activity and function of immune cells in the TME. Here, we report inorganic nanozymes (i.e., SnSe NSs) that mimic the catalytic activity of lactate dehydrogenase to degrade lactate to pyruvate, contributing to the metabolic treatment of tumors. As found in this study, SnSe NSs successfully decreased lactate levels in cells and tumors, as well as reduced tumor acidity. This is associated with activation of the immune response of T cells, thus alleviating the immunosuppressive environment of the TME. More importantly, the nanozyme successfully inhibited tumor growth in mutilate mouse tumor models. Thus, SnSe NSs show a promising result in lactate depletion and tumor suppression, which exemplifies its potential strategy in targeting lactate for metabolic therapy.

Engineered Extracellular Vesicles with SHP2 High Expression Promote Mitophagy for Alzheimer's Disease Treatment.

Mitochondrial dysfunction is a fundamental pathological feature of Alzheimer's disease (AD). However, toxicity and poor brain enrichment of existing mitophagy inducers limit their further applications. In this study, a platform for AD therapy is developed using nanosized mesenchymal-stem-cells-derived extracellular vesicles with tyrosine phosphatase-2 (SHP2) high-expression (MSC-EVs-SHP2). The high blood-brain barrier penetration ability of MSC-EVs-SHP2 is demonstrated in AD-mice, facilitating SHP2 delivery to the brain. In addition, MSC-EVs-SHP2 significantly induces mitophagy of neuronal cells, which alleviates mitochondrial damage-mediated apoptosis and NLRP3 inflammasome activation. Mitophagy further diminishes neuronal cells apoptosis and neuroinflammation, culminating with rescued synaptic loss and cognitive decline in an AD mouse model. The EV-engineering technology provides a potential platform for effective AD therapy by inducing mitophagy.

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.

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.

Coupling programmed cell death 1-positive tumor-infiltrating T cells with anti-programmed cell death 1 antibody improves the efficacy of adoptive T-cell therapy.

BACKGROUND AIMS: Adoptive cell therapy (ACT) with tumor-infiltrating lymphocytes (TILs) has shown great success in clinical trials. Programmed cell death 1 (PD-1)-expressing TILs show high specificity to autologous tumor cells. However, limited therapeutic efficiency is observed as a result of the tumor immune microenvironment (TIME). METHODS: Coupling PD-1+ex vivo-derived TILs with a monoclonal antibody against anti-PD-1 (aPD-1) reinvigorated the anti-tumor response of TILs against solid tumor without altering their high tumor targeting ability. RESULTS: Using a melanoma-bearing mouse model, PD-1+ TILs blocked with aPD-1 (PD-1+ TILs-aPD-1) exhibited a high capability for tumor targeting as well as improved anti-tumor response in TIME. Tumor growth was substantially delayed in the mice treated with PD-1+ TILs-aPD-1. CONCLUSIONS: The strategy utilizing TIL therapy coupled with immune checkpoint antibodies may extend to other therapeutic targets of ACT.

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.

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.

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.

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.

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.

Platelet-derived extracellular vesicles to target plaque inflammation for effective anti-atherosclerotic therapy.

Atherosclerosis is a kind of chronic inflammatory diseases characterized by dysfunction of local immune responses. Here we engineer platelet-derived extracellular vesicles (PEVs) to load MCC950, an NLRP3-inflammasome inhibitor, for atherosclerosis-targeted therapy. PEVs which are readily collected from the activated platelets selectively bind multiple cell types associated with the formation of atherosclerotic plaque in vivo. Intravenous administration of MCC950-PEVs could significantly reduce the formation of atherosclerotic plaques, lower the local inflammation and inhibit proliferation of macrophages and T cells at the plaque site compared with free drug administration in ApoE-KO mice. Our strategy suggests the promise of PEVs for targeted drug delivery for treatment of atherosclerosis.

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.