Preparation,physicochemical characterization and cytotoxicity in vitro of gemcitabine-loaded PEG-PDLLA nanovesicles

AIM:To investigate the preparation,physicochemical characterization and cytotoxicity in vitro of Gemcitabine-loaded poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-PDLLA) nanovesicles. METHODS:The nanovesicle carriers were prepared from the amphiphilic block copolymer of PEG-PDLLA by a double emulsion technique,and gemcitabine was used as the model drug. The morphology of the nanovesicles was determined by scanning and transmission electron microscopy,and the drug content,drug entrapment and drug-release curve in vitro were detected by UV-Vis-NIR spectrophotometry. Cytotoxicity in the human pancreatic cancer cell line SW1990 was tested by 3-(4,5-dimethyl) ethiazole (MTT) assay.RESULTS:The gemcitabine-loaded nanovesicles were hollow nanospheres with a mean size of 200.6 nm,drugloading of 4.14% and drug embedding ratio of 20.54%. The nanovesicles showed excellent controlled release that was characterized by a fast initial release during the first 72 h,followed by a slower and continuous release. The MTT assay demonstrated that gemcitabine-loaded nanovesicles exhibited dose-dependent and time-delayed cytotoxicity in the human pancreatic cancer cell line SW1990.CONCLUSION:Gemcitabine-loaded PEG-PDLLA nanovesicles prepared by a double emulsion technique exhibited good performance for controlled drug release,and had similar cytotoxic activity to free gem-citabine.

Cytotoxicity and Selectivity in Skin Cancer by SapC-DOPS Nanovesicles

Squamous cell carcinoma (SCC) and melanoma are malignant human cancers of the skin with an annual mortality that exceeds 10,000 cases every year in the USA alone. In this study, the lysosomal protein saposin C (SapC) and the phospholipid dioloylphosphatidylserine (DOPS) were assembled into cancer-selective nanovesicles (SapC-DOPS) and successfully tested using several in vitro and in vivo skin cancer models. Using MTT assay that measures the percentage of cell death, SapC-DOPS cytotoxic effect on three skin tumor cell lines (squamous cell carcinoma, SK-MEL-28, and MeWo) was compared to two normal nontumorigenic skin cells lines, normal immortalized keratinocyte (NIK) and human fibroblast cell (HFC). We observed that the nanovesicles selectively killed the skin cancer cells by inducing apoptotic cell death whereas untransformed skin cancer cells remained unaffected. Using subcutaneous skin tumor xenografts, animals treated with SapC-DOPS by subcutaneous injection showed a 79.4% by volume tumor reduced compared to the control after 4 days of treatment. We observed that the nanovesicles killed skin cancer cells by inducing apoptotic cell death compared to the control as revealed by TUNEL staining of xenograft tumor sections.

Targeted Macromolecules Delivery by Large Lipidic Nanovesicles Electrofusion with Mammalian Cells

Lipidic nanovesicles (so called liposomes) were one the earliest forms of nanovectors. One of their limits was our lack of knowledge on the delivery pathway of their content to the target cell cytoplasm. The present communication describes an efficient way to enhance the delivery. Pulsed electric fields (PEF) are known since the early 80’s to mediate a fusogenic state of plasma membranes when applied to a cell suspension or a tissue. Polykaryons are detected when PEF are applied on cells in contact during or after the pulses. Heterofusion can be obtained when a cell mixture is pulsed. When lipidic nanovesicles, either small unilamellar vesicles (SUVs) or large unilamellar vesicles (LUVs), are electrostatically brought in contact with electropermeabilized cells by a salt bridge, their content is delivered into the cytoplasm in electropermeabilized cells. The PEF parameters are selected to affect specifically the cells leaving the vesicles unaffected. It is the electropermeabilized state of the cell membrane that is the trigger of the merging between the plasma membrane and the lipid bilayer. The present investigation shows that the transfer of macromolecules can be obtained;i.e. 20 kD dextrans can be easily transferred while a direct transfer does not take place under the same electrical parameters. Cell viability was not affected by the treatment. As delivery is present only on electropermeabilized cells, a targeting of the effect is obtained in the volume where the PEF parameters are over the critical value for electropermeabilization. A homogeneous cytoplasm labeling is observed under digitised videomicroscopy. The process is a content and “membrane” mixing, following neither a kiss and run or an endocytotic pathway.

Herbal medicine-derived nanovesicles: basic characteristics and biological activities

Herbal medicine(HM)has been extensively researched and widely used since ancient times.Currently,as one of the emerging directions in HM modernization research,herbal medicine-derived nanovesicles(HMDNV),a type of nanoparticle obtained from destructed plant tissues,hold considerable promise for disease treatment and drug delivery.The recent studies related to HMDNV and miRNAs are summarized in this review,with a special emphasis on their basic characteristics and biological activities,to provide ideas for future scientific research on HMDNV and enrich the content of active components of Traditional Chinese Medicine(TCM).

Plant-derived nanovesicles as an emerging platform for cancer therapy

Plant-derived nanovesicles(PDNVs)derived from natural green products have emerged as an attractive nanoplatform in biomedical application.They are usually characterized by unique structural and biological functions,such as the bioactive lipids/proteins/nucleic acids as therapeutics and targeting groups,immune-modulation,and long-term circulation.With the rapid development of nanotechnology,materials,and synthetic chemistry,PDNVs can be engineered with multiple functions for efficient drug delivery and specific killing of diseased cells,which represent an innovative biomaterial with high biocompatibility for fighting against cancer.In this review,we provide an overview of the state-of-theart studies concerning the development of PDNVs for cancer therapy.The original sources,methods for obtaining PDNVs,composition and structure are introduced systematically.With an emphasis on the featured application,the inherent anticancer properties of PDNVs as well as the strategies in constructing multifunctional PDNVs-based nanomaterials will be discussed in detail.Finally,some scientific issues and technical challenges of PDNVs as promising options in improving anticancer therapy will be discussed,which are expected to promote the further development of PDNVs in clinical translation.

Bioinspired engineering ADSC nanovesicles thermosensitive hydrogel enhance autophagy of dermal papilla cells for androgenetic alopecia treatment

Androgenic alopecia(AGA)is a highly prevalent form of non-scarring alopecia but lacks effective treatments.Stem cell exosomes have similar repair effects to stem cells,suffer from the drawbacks of high cost and low yield yet.Cell-derived nanovesicles acquired through mechanical extrusion exhibit favorable biomimetic properties similar to exosomes,enabling them to efficiently encapsulate substantial quantities of therapeutic proteins.In this study,we observed that JAM-A,an adhesion protein,resulted in a significantly increased the adhesion and resilience of dermal papilla cells to form snap structures against damage caused by dihydrotestosterone and macrophages,thereby facilitating the process of hair regrowth in cases of AGA.Consequently,adipose-derived stem cells were modified to overexpress JAM-A to produce engineered JAM-A overexpressing nanovesicles(JAM-A^(OE)@NV).The incorporation of JAM-A^(OE)@NV into a thermosensitive hydrogel matrix(JAM-A^(OE)@NV Gel)to effectively addresses the limitations associated with the short half-life of JAM-A^(OE)@NV,and resulted in the achievement of a sustained-release profile for JAM-A^(OE)@NV.The physicochemical characteristics of the JAM-A^(OE)@NV Gel were analyzed and assessed for its efficacy in promoting hair regrowth in vivo and vitro.The JAM-A^(OE)@NV Gel,thus,presents a novel therapeutic approach and theoretical framework for promoting the treatment of low cell adhesion diseases similar to AGA.

Rhizoma Drynariae-derived nanovesicles reverse osteoporosis by potentiating osteogenic differentiation of human bone marrow mesenchymal stem cells via targeting ERα signaling

Although various anti-osteoporosis drugs are available,the limitations of these therapies,including drug resistance and collateral responses,require the development of novel anti-osteoporosis agents.Rhizoma Drynariae displays a promising anti-osteoporosis effect,while the effective component and mechanism remain unclear.Here,we revealed the therapeutic potential of Rhizoma Drynariae-derived nanovesicles(RDNVs)for postmenopausal osteoporosis and demonstrated that RDNVs potentiated osteogenic differentiation of human bone marrow mesenchymal stem cells(hBMSCs)by targeting estrogen receptor-alpha(ERα).RDNVs,a natural product isolated from fresh Rhizoma Drynariae root juice by differential ultracentrifugation,exhibited potent bone tissue-targeting activity and anti-osteoporosis efficacy in an ovariectomized mouse model.RDNVs,effectively internalized by hBMSCs,enhanced proliferation and ERαexpression levels of hBMSC,and promoted osteogenic differentiation and bone formation.Mechanistically,via the ERαsignaling pathway,RDNVs facilitated mRNA and protein expression of bone morphogenetic protein 2 and runt-related transcription factor 2 in hBMSCs,which are involved in regulating osteogenic differentiation.Further analysis revealed that naringin,existing in RDNVs,was the active component targeting ERαin the osteogenic effect.Taken together,our study identified that naringin in RDNVs displays exciting bone tissue-targeting activity to reverse osteoporosis by promoting hBMSCs proliferation and osteogenic differentiation through estrogen-like effects.

Tailoring therapeutics via a systematic beneficial elements comparison between photosynthetic bacteria-derived OMVs and extruded nanovesicles

Photosynthetic bacteria(PSB)has shown significant potential as a drug or drug delivery system owing to their photothermal capabilities and antioxidant properties.Nevertheless,the actualization of their potential is impeded by inherent constraints,including their considerable size,heightened immunogenicity and compromised biosafety.Conquering these obstacles and pursuing more effective solutions remains a top priority.Similar to extracellular vesicles,bacterial outer membrane vesicles(OMVs)have demonstrated a great potential in biomedical applications.OMVs from PSB encapsulate a rich array of bioactive constituents,including proteins,nucleic acids,and lipids inherited from their parent cells.Consequently,they emerge as a promising and practical alternative.Unfortunately,OMVs have suffered from low yield and inconsistent particle sizes.In response,bacteria-derived nanovesicles(BNVs),created through controlled extrusion,adeptly overcome the challenges associated with OMVs.However,the differences,both in composition and subsequent biological effects,between OMVs and BNVs remain enigmatic.In a groundbreaking endeavor,our study meticulously cultivates PSB-derived OMVs and BNVs,dissecting their nuances.Despite minimal differences in morphology and size between PSB-derived OMVs and BNVs,the latter contains a higher concentration of active ingredients and metabolites.Particularly noteworthy is the elevated levels of lysophosphatidylcholine(LPC)found in BNVs,known for its ability to enhance cell proliferation and initiate downstream signaling pathways that promote angiogenesis and epithelialization.Importantly,our results indicate that BNVs can accelerate wound closure more effectively by orchestrating a harmonious balance of cell proliferation and migration within NIH-3T3 cells,while also activating the EGFR/AKT/PI3K pathway.In contrast,OMVs have a pronounced aptitude in anti-cancer efforts,driving macrophages toward the M1 phenotype and promoting the release of inflammatory cytokines.Thus,our findings not only provide a promising methodological framework but also establish a definitive criterion for discerning the optimal application of OMVs and BNVs in addressing a wide range of medical conditions.

Click-hydrogel delivered aggregation-induced emissive nanovesicles for simultaneous remodeling and antibiosis of deep burn wounds

As a high-risk trauma,deep burns are always hindered in their repair process by decreased tissue regeneration capacity and persistent infections.In this study,we developed a simultaneous strategy for deep burn wounds treatment using functional nanovesicles with antibacterial and tissue remodeling properties,delivered via a click-chemistry hydrogel.An aggregation-induced emission photosensitizer of 4-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)vinyl)-1-(2-hydroxyethyl)pyridin-1-ium bromide(THB)with excellent photodynamic properties was first prepared,and then combined with readily accessible adipose stem cells-derived nanovesicles to generate the THB functionalized nanovesicles(THB@ANVs).The THB@ANVs showed strong antibacterial activity against Gram-positive bacteria(up to 100%killing rate),and also beneficial effects on tissue remodeling,including promoting cell migration,cell proliferation,and regulating immunity.In addition,we prepared a click-hydrogel of carboxymethyl chitosan for effective delivery of THB@ANVs on wounds.This hydrogel could be injected to conform to the wound morphology while responding to the acidic microenvironment.In vivo evaluations of wound healing revealed that the THB@ANVs hydrogel dressing efficiently accelerated the healing of second-degree burn wounds by reducing bacterial growth,regulating inflammation,promoting early angiogenesis,and collagen deposition.This study provides a promising candidate of wound dressing with diverse functions for deep burn wound repair.

Isolation of cabbage exosome-like nanovesicles and investigation of their biological activities in human cells

There are extensive studies on the applications of extracellular vesicles(EVs)produced in cell culture for therapeutic drug development.However,large quantities of EVs are needed for in vivo applications,which requires high production costs and time.Thus,the development of new EV sources is essential to facilitate their use.Accordingly,plant-derived exosome-like nanovesicles are an emerging alternative for culture-derived EVs.Until now,however,few studies have explored their biological functions and uses.Therefore,it is necessary to elucidate biological activities of plant-derived exosome-like nanovesicles and harness vesicles for biomedical applications.Herein,cabbage and red cabbage were used as nanovesicle sources owing to their easy cultivation.First,an efficient method for nanovesicle isolation from cabbage(Cabex)and red cabbage(Rabex)was developed.Furthermore,isolated nanovesicles were characterized,and their biological functions were assessed.Both Cabex and Rabex promoted mammalian cell proliferation and,interestingly,suppressed inflammation in immune cells and apoptosis in human keratinocytes and fibroblasts.Finally,therapeutic drugs were encapsulated in Cabex or Rabex and successfully delivered to human cells,demonstrating the potential of these vesicles as alternative drug delivery vehicles.Overall,the current results provide strong evidence for the wide application of Cabex and Rabex as novel therapeutic biomaterials.

Macrophage membrane-coated nanovesicles for dual-targeted drug delivery to inhibit tumor and induce macrophage polarization

Background:Immunosuppressive M2 macrophages in the tumor microenvironment(TME)can mediate the therapeutic resistance of tumors,and seriously affect the clinical efficacy and prognosis of tumor patients.This study aims to develop a novel drug delivery system for dual-targeting tumor and macrophages to inhibit tumor and induce macrophage polarization.Methods:The anti-tumor effects of methyltransferase like 14(METTL14)were investigated both in vitro and in vivo.The underlying mechanisms of METTL14 regulating macrophages were also explored in this study.We further constructed the cyclic(Arg-Gly-Asp)(cRGD)peptide modified macrophage membrane-coated nanovesicles to co-deliver METTL14 and the TLR4 agonist.Results:We found that METTL14 significantly inhibits the growth of tumor in vitro.METTL14 might downregulate TICAM2 and inhibit the Toll-like receptor 4(TLR4)pathway of macrophages,meanwhile,the combination of METTL14 and the TLR4 agonist could induce M1 polarization of macrophages.Macrophage membrane-coated nanovesicles are characterized by easy modification,drug loading,and dual-targeting tumor and macrophages,and cRGD modification can further enhance its targeting ability.It showed that the nanovesicles could improve the in vivo stability of METTL14,and dual-target tumor and macrophages to inhibit tumor and induce M1 polarization of macrophages.Conclusions:This study anticipates achieving the dual purposes of tumor inhibition and macrophage polarization,and providing a new therapeutic strategy for tumors.

Cell-derived nanovesicles from mesenchymal stem cells as extracellular vesicle-mimetics in wound healing

Wound healing is a dynamic process that involves a series of molecular and cellular events aimed at replacing devitalized and missing cellular components and/or tissue layers.Recently,extracellular vesicles(EVs),naturally cell-secreted lipid membrane-bound vesicles laden with biological cargos including proteins,lipids,and nucleic acids,have drawn wide attention due to their ability to promote wound healing and tissue regeneration.However,current exploitation of EVs as therapeutic agents is limited by their low isolation yields and tedious isolation processes.To circumvent these challenges,bioinspired cell-derived nanovesicles(CDNs)that mimic EVs were obtained by shearing mesenchymal stem cells(MSCs)through membranes with different pore sizes.Physical characterisations and highthroughput proteomics confirmed that MSC-CDNs mimicked MSC-EVs.Moreover,these MSC-CDNs were efficiently uptaken by human dermal fibroblasts and demonstrated a dose-dependent activation of MAPK signalling pathway,resulting in enhancement of cell proliferation,cell migration,secretion of growth factors and extracellular matrix proteins,which all promoted tissue regeneration.Of note,MSC-CDNs enhanced angiogenesis in human dermal microvascular endothelial cells in a 3D PEGfibrin scaffold and animal model,accelerating wound healing in vitro and in vivo.These findings suggest that MSC-CDNs could replace both whole cells and EVs in promoting wound healing and tissue regeneration.

Exosome-mimicking nanovesicles derived from efficacy-potentiated stem cell membrane and secretome for regeneration of injured tissue

Translation of exosome-based therapies to pharmaceutical use is hindered by difficulties in large-scale and cost-effective production of clinical-grade exosomes.The rational design of nanovesicles that mimic the functionalities and physicochemical properties of exosomes may circumvent these issues.In this study,membranes and secretome from efficacy-potentiated mesenchymal stem cells(MSCs)were developed into size-controllable nanovesicles(Meseomes).MSCs were primed with interferon-y(IFNy)and tumor necrosis factor-a(TNFa),harvested,and exosome-mimicking Meseomes were subsequently synthesized via one-step extrusion.Meseomes demonstrated significant enhancement of pro-angiogenic,pro-proliferative,antiinflammatory,and anti-fibrotic effects on endothelial cells,macrophages,and hepatic stellate cells in vitro.Meseomes from primed MSCs benefited from an enrichment of bioactive and therapeutic molecules compared to nanovesicles from unprimed MSCs,as validated by liquid chromatography-mass spectrometry(LC-MS)proteomic analysis.Systemic administration of Meseomes to acute liver injury models resulted in the recovery of liver function,attenuated tissue necrosis.Further assessment of locally administered Meseomes in acute hindlimb ischemia models resulted in the salvage of the majority of the ischemic hindlimb(>80%),which was due to enhanced angiogenesis and M2 macrophage polarization.The versatility and therapeutic efficacy of our developed acellular Meseomes offer an appealing alternative to traditional cell or exosome therapies for regenerative and translational medicine.

Mild hyperthermia-enhanced chemo-photothermal synergistic therapy using doxorubicin-loaded gold nanovesicles

Gold nanovesicles(GVs) with unique plasmonic property and large cavity hold great potential as a stimuli-responsive nanocarrier to deliver drugs for efficient tumor chemotherapy and other therapies synergistically.Herein,we developed doxorubicin-loaded gold nanovesicles(DGVs),offering infrared thermal(IRT) and photoacoustic(PA) dual-modal imaging guided mild hype rthermia-enhanced chemophotothermal cancer synergistic therapy.The DGVs are self-assembled by gold nanoparticles modified with amphiphilic copolymer in a predetermined concentration of doxorubicin through film rehydration method.Under the influence of laser excitation,the as-prepared DGVs exhibited good photothermal effect,which triggered the structural disruption of GVs and thus,allowed the efficient release of encapsulated DOX to enhance cell uptake for fluorescence imaging and tumor chemotherapy,respectively.In addition,DGVs also showed a strong PA and IRT signals in vivo.Our study demonstrated the potential of DGVs as stimuli-responsive drug delivery systems and cancer theranostics.

Comparison of extruded cell nanovesicles and exosomes in their molecular cargos and regenerative potentials

Extracellular vesicles(EVs)generated from mesenchymal stem cells(MSCs)play an essential role in modulating cell–cell communication and tissue regeneration.The clinical translation of EVs is constrained by the poor yield of EVs.Extrusion has recently become an effective technique for producing a large scale of nanovesicles(NVs).In this study,we systematically compared MSC NVs(from extrusion)and EVs(from natural secretion).Proteomics and RNA sequencing data revealed that NVs resemble MSCs more closely than EVs.Additionally,microRNAs in NVs are related to cardiac repair,fibrosis repression,angiogenesis.Lastly,intravenous delivery of MSC NVs improved heart repair and cardiac function in a mouse model of myocardial infarction.

Plant-derived nanovesicles: Further exploration of biomedical function and application potential

Extracellular vesicles(EVs)are phospholipid bilayer vesicles actively secreted by cells,that contain a variety of functional nucleic acids,proteins,and lipids,and are important mediums of intercellular communication.Based on their natural properties,EVs can not only retain the pharmacological effects of their source cells but also serve as natural delivery carriers.Among them,plant-derived nanovesicles(PNVs)are characterized as natural disease therapeutics with many advantages such as simplicity,safety,eco-friendliness,low cost,and low toxicity due to their abundant resources,large yield,and low risk of immunogenicity in vivo.This review systematically introduces the biogenesis,isolation methods,physical characterization,and components of PNVs,and describes their administration and cellular uptake as therapeutic agents.We highlight the therapeutic potential of PNVs as therapeutic agents and drug delivery carriers,including anti-inflammatory,anticancer,wound healing,regeneration,and antiaging properties as well as their potential use in the treatment of liver disease and COVID-19.Finally,the toxicity and immunogenicity,the current clinical application,and the possible challenges in the future development of PNVs were analyzed.We expect the functions of PNVs to be further explored to promote clinical translation,thereby facilitating the development of a new framework for the treatment of human diseases.

Tuning the Stability of the Polyplex Nanovesicles of Oligonucleotides via a Zinc(Ⅱ)-Coordinative Strategy

Oligonucleotide therapeutics have great potential to target the currently undruggable genes and to generate entirely new therapeutic paradigms in multiple types of disease,thus having attracted much attention in recent years.However,their applications are greatly hindered by a lack of safe and efficient oligonucleotide-delivery vectors.Polyplex nanovesicles formed from oligonucleotides and the cationic block have shown exceptional features for the delivery of therapeutic oligonucleotides and other biopharmaceuticals.Nevertheless,these polyplex nanovesicles are deeply fraught with difficulty in tolerating physiological ionic strength.Inspired by the high binding ability between the dipicolylamine(DPA)/zinc(Ⅱ)complex and the phosphodiester moieties of oligonucleotides,herein,we designed a coordinative cationic block to solve the intrinsic stability dilemma.Moreover,we found the stability of the resulted polyplex nanovesicles could be easily tuned by the content of coordinated zinc ions.In vitro cellular studies implied that the prepared zinc(Ⅱ)-coordinative polyplex nanovesicles preferred to retain in the lysosomes upon internalization,making them ideal delivery candidates for the lysosome-targeting oligonucleotide therapeutics.

Inhibiting collagen Ⅰ production and tumor cell colonization in the lung via miR-29a-3p loading of exosome-/liposome-based nanovesicles

The lung is one of the most common sites for cancer metastasis.Collagens in the lung provide a permissive microenvironment that supports the colonization and outgrowth of disseminated tumor cells.Therefore,down-regulating the production of collagens may contribute to the inhibition of lung metastasis.It has been suggested that mi R-29 exhibits effective anti-fibrotic activity by negatively regulating the expression of collagens.Indeed,our clinical lung tumor data shows that mi R-29 a-3 p expression negatively correlates with collagen I expression in lung tumors and positively correlates with patients’outcomes.However,suitable carriers need to be selected to deliver this therapeutic mi RNA to the lungs.In this study,we found that the chemotherapy drug cisplatin facilitated mi R-29 a-3 p accumulation in the exosomes of lung tumor cells,and this type of exosomes exhibited a specific lung-targeting effect and promising collagen down-regulation.To scale up the preparation and simplify the delivery system,we designed a lung-targeting liposomal nanovesicle(by adjusting the molar ratio of DOTAP/cholesterol-mi RNAs to 4:1)to carry mi R-29 a-3 p and mimic the exosomes.This liposomal nanovesicle delivery system significantly down-regulated collagen I secretion by lung fibroblasts in vivo,thus alleviating the establishment of a pro-metastatic environment for circulating lung tumor cells.

Cellular nanovesicles for therapeutic immunomodulation:A perspective on engineering strategies and new advances

Cellular nanovesicles which are referred to as cell-derived,nanosized lipid bilayer structures,have emerged as a promising platform for regulating immune responses.Owing to their outstanding advantages such as high biocompatibility,prominent structural stability,and high loading capacity,cellular nanovesicles are suitable for delivering various immunomodulatory molecules,such as small molecules,nucleic acids,peptides,and proteins.Immunomodulation induced by cellular nanovesicles has been exploited to modulate immune cell behaviors,which is considered as a novel cell-free immunotherapeutic strategy for the prevention and treatment of diverse diseases.Here we review emerging concepts and new advances in leveraging cellular nanovesicles to activate or suppress immune responses,with the aim to explicate their applications for immunomodulation.We overview the general considerations and principles for the design of engineered cellular nanovesicles with tailored immunomodulatory activities.We also discuss new advances in engineering cellular nanovesicles as immunotherapies for treating major diseases.

Engineering SIRPα cellular membrane-based nanovesicles for combination immunotherapy

Immune checkpoint inhibitors(ICIs)have revolutionized cancer treatment for their unprecedented clinical efficacy.Signal regulatory proteinα(SIRPα)is a phagocytic checkpoint expressed on macrophages,dendritic cells,other myeloid cells.Cancer cells inhibit macrophage phagocytosis through the interaction of the CD47-SIRPαaxis.Disrupting the CD47-SIRPαaxis has therefore been a promising strategy in restoring the immune attack against cancer.Herein,we engineered cellular membrane nanovesicles(NVs)presenting SIRPαreceptors for phagocytosis checkpoint blockade to augment the antitumor immune response.Furthermore,zebularine(Zeb),an inhibitor of DNA methyltransferase,was encapsulated into SIRPαNVs to reprogram the immunosuppressive tumor microenvironment together with blockade of phagocytosis checkpoint.It is demonstrated that SIRPα@Zeb can improve tumor immunogenicity,the polarization of tumor-associated macrophages to the M1 phenotype,increase the infiltration of CD8^(+)T lymphocytes in tumors.The robust antitumor immune response induced by SIRPα@Zeb significantly suppressed tumor growth and extended mice-bearing melanoma xenograft survival.