Platelet homeostasis is regulated by platelet expression of CD47 under normal conditions and in passive immune thrombocytopenia

Cell Membrane-Coated Nanoparticles for Dental, Oral, and Craniofacial Diseases

Dental, oral, and craniofacial diseases can substantially impact the quality of human life, thereby posing a serious public health concern. Although conventional therapies such as surgery have solved these problems largely, the prognosis of patients is not always satisfactory. Cell membrane-coated nanoparticles (CMCNPs) carry nanodrugs with the help of natural cell membranes, therefore utilizing their remarkable ability to interface and interact with their surrounding environment. These nanoparticles have demonstrated substantial advantages in drug targeting, prolonging blood circulation time, penetrating biofilms, and immune escape. With the assistance of CMCNPs, the therapeutic effects of dental, oral, and craniofacial diseases can reach a higher level. CMCNPs have been applied for dental, oral, and craniofacial diseases for various conditions such as head and neck cancer, periodontal disease, and oral biosignal detection. For the therapies of head and neck cancer, CMCNPs have been widely utilized as a tool of chemotherapy, phototherapy, and immunotherapy, while yet to be exploited in imaging technique. In the end, we summarized the challenges and prospectives of CMCNPs for dental, oral, and craniofacial diseases: large-scale production with uniform standards and high quantity, extensive application directions in dental, oral, and craniofacial regions (implant, endodontics), and the promotion of its clinical application.

From bench to bedside: Platelet biomimetic nanoparticles as a promising carriers for personalized drug delivery

In recent decades, there has been a burgeoning interest in cell membrane coating strategies as innovative approach for targeted delivery systems in biomedical applications. Platelet membrane-coated nanoparticles (PNPs), in particular, are gaining interest as a new route for targeted therapy due to their advantages over conventional drug therapies. Their stepwise approach blends the capabilities of the natural platelet membrane (PM) with the adaptable nature of manufactured nanomaterials, resulting in a synergistic combination that enhances drug delivery and enables the development of innovative therapeutics. In this context, we present an overview of the latest advancements in designing PNPs with various structures tailored for precise drug delivery. Initially, we describe the types, preparation methods, delivery mechanisms, and specific advantages of PNPs. Next, we focus on three critical applications of PNPs in diseases: vascular disease therapy, cancer treatment, and management of infectious diseases. This review presents our knowledge of PNPs, summarizes their advancements in targeted therapies and discusses the promising potential for clinical translation of PNPs.

Platelet Membrane-Camouflaged Silver Metal-Organic Framework Biomimetic Nanoparticles for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is characterized by high malignancy and limited treatment options. Given the pressing need for more effective treatments for TNBC, this study aimed to develop platelet membrane (PM)-camouflaged silver metal-organic framework nanoparticles (PM@MOF-Ag NPs), a biomimetic nanodrug. PM@MOF-Ag NP construction involved the utilization of 2-methylimidazole and silver nitrate to prepare silver metal-organic framework (MOF-Ag) NPs. The PM@MOF-Ag NPs, due to their camouflage, possess excellent blood compatibility, immune escape ability, and a strong affinity for 4T1 tumor cells. This enhances their circulation time in vivo and promotes the aggregation of PM@MOF-Ag NPs at the 4T1 tumor site. Importantly, PM@MOF-Ag NPs demonstrated promising antitumor activity in vitro and in vivo. We further revealed that PM@MOF-Ag NPs induced tumor cell death by overproducing reactive oxygen species and promoting cell apoptosis. Moreover, PM@MOF-Ag NPs enhanced apoptosis by upregulating the ratios of Bax/Bcl-2 and cleaved caspase3/pro-caspase3. Notably, PM@MOF-Ag NPs exhibited no significant organ toxicity, whereas the administration of MOF-Ag NPs resulted in liver inflammation compared to the control group.

Hybrid Membrane-Coated Nanoparticles for Precise Targeting and Synergistic Therapy in Alzheimer's Disease

The blood brain barrier (BBB) limits the application of most therapeutic drugs for neurological diseases (NDs). Hybrid cell membrane-coated nanoparticles derived from different cell types can mimic the surface properties and functionalities of the source cells, further enhancing their targeting precision and therapeutic efficacy. Neuroinflammation has been increasingly recognized as a critical factor in the pathogenesis of various NDs, especially Alzheimer's disease (AD). In this study, a novel cell membrane coating is designed by hybridizing the membrane from platelets and chemokine (C-C motif) receptor 2 (CCR2) cells are overexpressed to cross the BBB and target neuroinflammatory lesions. Past unsuccessful endeavors in AD drug development underscore the challenge of achieving favorable outcomes when utilizing single-mechanism drugs.Two drugs with different mechanisms of actions into liposomes are successfully loaded to realize multitargeting treatment. In a transgenic mouse model for familial AD (5xFAD), the administration of these drug-loaded hybrid cell membrane liposomes results in a significant reduction in amyloid plaque deposition, neuroinflammation, and cognitive impairments. Collectively, the hybrid cell membrane-coated nanomaterials offer new opportunities for precise drug delivery and disease-specific targeting, which represent a versatile platform for targeted therapy in AD.

Cell-membrane engineering strategies for clinic-guided design of nanomedicine

Cells are the fundamental units of life. The cell membrane primarily composed of two layers of phospholipids (a bilayer) structurally defines the boundary of a cell, which can protect its interior from external disturbances and also selectively exchange substances and conduct signals from the extracellular environment. The complexity and particularity of transmembrane proteins provide the foundation for versatile cellular functions. Nanomedicine as an emerging therapeutic strategy holds tremendous potential in the healthcare field. However, it is susceptible to recognition and clearance by the immune system. To overcome this bottleneck, the technology of cell membrane coating has been extensively used in nanomedicines for their enhanced therapeutic efficacy, attributed to the favorable fluidity and biocompatibility of cell membranes with various membrane-anchored proteins. Meanwhile, some engineering strategies of cell membranes through various chemical, physical and biological ways have been progressively developed to enable their versatile therapeutic functions against complex diseases. In this review, we summarized the potential clinical applications of four typical cell membranes, elucidated their underlying therapeutic mechanisms, and outlined their current engineering approaches. In addition, we further discussed the limitation of this technology of cell membrane coating in clinical applications, and possible solutions to address these challenges.

Thrombocytopenia Independently Leads to Changes in Monocyte Immune Function

BACKGROUND

While platelets have well-studied hemostatic functions, platelets are immune cells that circulate at the interface between the vascular wall and white blood cells. The physiological implications of these constant transient interactions are poorly understood. Activated platelets induce and amplify immune responses, but platelets may also maintain immune homeostasis in healthy conditions, including maintaining vascular integrity and T helper cell differentiation, meaning that platelets are central to both immune responses and immune quiescence. Clinical data have shown an association between low platelet counts (thrombocytopenia) and immune dysfunction in patients with sepsis and extracorporeal membrane oxygenation, further implicating platelets as more holistic immune regulators, but studies of platelet immune functions in nondisease contexts have had limited study.

METHODS

We used in vivo models of thrombocytopenia and in vitro models of platelet and monocyte interactions, as well as RNA-seq and ATAC-seq (assay for transposase-accessible chromatin with sequencing), to mechanistically determine how resting platelet and monocyte interactions immune program monocytes.

RESULTS

Circulating platelets and monocytes interact in a CD47-dependent manner to regulate monocyte metabolism, histone methylation, and gene expression. Resting platelet-monocyte interactions limit TLR (toll-like receptor) signaling responses in healthy conditions in an innate immune training-like manner. In both human patients with sepsis and mouse sepsis models, thrombocytopenia exacerbated monocyte immune dysfunction, including increased cytokine production.

CONCLUSIONS

Thrombocytopenia immune programs monocytes in a manner that may lead to immune dysfunction in the context of sepsis. This is the first demonstration that sterile, endogenous cell interactions between resting platelets and monocytes regulate monocyte metabolism and pathogen responses, demonstrating platelets to be immune rheostats in both health and disease.

CD47 is Required for Mesenchymal Progenitor Proliferation and Fracture Repair

CD47 is a ubiquitous and pleiotropic cell-surface receptor. Disrupting CD47 enhances injury repair in various tissues but the role of CD47 has not been studied in bone injuries. In a murine closed-fracture model, CD47-null mice showed decreased callus bone volume, bone mineral content, and tissue mineral content as assessed by microcomputed tomography 10 days post-fracture, and increased fibrous volume as determined by histology. To understand the cellular basis for this phenotype, mesenchymal progenitors (MSC) were harvested from bone marrow. CD47-null MSC showed decreased large fibroblast colony formation (CFU-F), significantly less proliferation, and fewer cells in S-phase, although osteoblast differentiation was unaffected. However, consistent with prior research, CD47-null endothelial cells showed increased proliferation relative to WT cells. Similarly, in a murine ischemic fracture model, CD47-null mice showed reduced fracture callus bone volume and bone mineral content relative to WT. Consistent with our In vitro results, in vivo EdU labeling showed decreased cell proliferation in the callus of CD47-null mice, while staining for CD31 and endomucin demonstrated increased endothelial cell mass. Finally, WT mice administered a CD47 morpholino, which blocks CD47 protein production, showed a callus phenotype similar to that of non-ischemic and ischemic fractures in CD47-null mice, suggesting the phenotype was not due to developmental changes in the knockout mice. Thus, inhibition of CD47 during bone healing reduces both non-ischemic and ischemic fracture healing, in part, by decreasing MSC proliferation. Furthermore, the increase in endothelial cell proliferation and early blood vessel density caused by CD47 disruption is not sufficient to overcome MSC dysfunction.

CD47 is Required for Mesenchymal Progenitor Proliferation and Fracture Repair

CD47 is a ubiquitous and pleiotropic cell-surface receptor. Disrupting CD47 enhances injury repair in various tissues but the role of CD47 has not been studied in bone injuries. In a murine closed-fracture model, CD47-null mice showed decreased callus bone volume, bone mineral content, and tissue mineral content as assessed by microcomputed tomography 10 days post-fracture, and increased fibrous volume as determined by histology. To understand the cellular basis for this phenotype, mesenchymal progenitors (MSC) were harvested from bone marrow. CD47-null MSC showed decreased large fibroblast colony formation (CFU-F), significantly less proliferation, and fewer cells in S-phase, although osteoblast differentiation was unaffected. However, consistent with prior research, CD47-null endothelial cells showed increased proliferation relative to WT cells. Similarly, in a murine ischemic fracture model, CD47-null mice showed reduced fracture callus bone volume and bone mineral content relative to WT. Consistent with our in vitro results, in vivo EdU labeling showed decreased cell proliferation in the callus of CD47-null mice, while staining for CD31 and endomucin demonstrated increased endothelial cell mass. Finally, WT mice administered a CD47 morpholino, which blocks CD47 protein production, showed a callus phenotype similar to that of non-ischemic and ischemic fractures in CD47-null mice, suggesting the phenotype was not due to developmental changes in the knockout mice. Thus, inhibition of CD47 during bone healing reduces both non-ischemic and ischemic fracture healing, in part, by decreasing MSC proliferation. Furthermore, the increase in endothelial cell proliferation and early blood vessel density caused by CD47 disruption is not sufficient to overcome MSC dysfunction.

Maintaining sidedness and fluidity in cell membrane coatings supported on nano-particulate and planar surfaces

Supported cell membrane coatings meet many requirements set to bioactive nanocarriers and materials, provided sidedness and fluidity of the natural membrane are maintained upon coating. However, the properties of a support-surface responsible for maintaining correct sidedness and fluidity are unknown. Here, we briefly review the properties of natural membranes and membrane-isolation methods, with focus on the asymmetric distribution of functional groups in natural membranes (sidedness) and the ability of molecules to float across a membrane to form functional domains (fluidity). This review concludes that hydrophilic sugar-residues of glycoproteins in the outer-leaflet of cell membranes direct the more hydrophobic inner-leaflet towards a support-surface to create a correctly-sided membrane coating, regardless of electrostatic double-layer interactions. On positively-charged support-surfaces however, strong, electrostatic double-layer attraction of negatively-charged membranes can impede homogeneous coating. In correctly-sided membrane coatings, fluidity is maintained regardless of whether the surface carries a positive or negative charge. However, membranes are frozen on positively-charged, highly-curved, small nanoparticles and localized nanoscopic structures on a support-surface. This leaves an unsupported membrane coating in between nanostructures on planar support-surfaces that is in dual-sided contact with its aqueous environment, yielding enhanced fluidity in membrane coatings on nanostructured, planar support-surfaces as compared with smooth ones.

Engineering Platelet Membrane Imitating Nanoparticles for Targeted Therapeutic Delivery

Platelet Membrane Imitating Nanoparticles (PMINs) is a novel drug delivery system that imitates the structure and functionality of platelet membranes. PMINs imitate surface markers of platelets to target specific cells and transport therapeutic cargo. PMINs are engineered by incorporating the drug into the platelet membrane and encapsulating it in a nanoparticle scaffold. This allows PMINs to circulate in the bloodstream and bind to target cells with high specificity, reducing off-target effects and improving therapeutic efficacy. The engineering of PMINs entails several stages, including the separation and purification of platelet membranes, the integration of therapeutic cargo into the membrane, and the encapsulation of the membrane in a nanoparticle scaffold. In addition to being involved in a few pathological conditions including cancer, atherosclerosis, and rheumatoid arthritis, platelets are crucial to the body's physiological processes. This study includes the preparation and characterization of platelet membrane-like nanoparticles and focuses on their most recent advancements in targeted therapy for conditions, including cancer, immunological disorders, atherosclerosis, phototherapy, etc. PMINs are a potential drug delivery system that combines the advantages of platelet membranes with nanoparticles. The capacity to create PMMNs with particular therapeutic cargo and surface markers provides new possibilities for targeted medication administration and might completely change the way that medicine is practiced. Despite the need for more studies to optimize the engineering process and evaluate the effectiveness and safety of PMINs in clinical trials, this technology has a lot of potential.

In Silico, In Vitro, and In Vivo Evaluation of Caffeine-Coated Nanoparticles as a Promising Therapeutic Avenue for AML through NF-Kappa B and TRAIL Pathways Modulation

BACKGROUND

Advancements in nanoscience have led to a profound paradigm shift in the therapeutic applications of medicinally important natural drugs. The goal of this research is to develop a nano-natural product for efficient cancer treatment.

METHODS AND RESULTS

For this purpose, mesoporous silica nanoparticles (MSNPs) were formulated, characterized, and loaded with caffeine to develop a targeted drug delivery system, i.e., caffeine-coated nanoparticles (CcNPs). In silico docking studies were conducted to examine the binding efficiency of the CcNPs with different apoptotic targets followed by in vitro and in vivo bioassays in respective animal models. Caffeine, administered both as a free drug and in nanomedicine form, along with doxorubicin, was delivered intravenously to a benzene-induced AML model. The anti-leukemic potential was assessed through hematological profiling, enzymatic biomarker analysis, and RT-PCR examination of genetic alterations in leukemia markers. Docking studies show strong inter-molecular interactions between CcNPs and apoptotic markers. In vitro analysis exhibits statistically significant antioxidant activity, whereas in vivo analysis exhibits normalization of the genetic expression of leukemia biomarkers STMN1 and S1009A, accompanied by the restoration of the hematological and morphological traits of leukemic blood cells in nanomedicine-treated rats. Likewise, a substantial improvement in hepatic and renal biomarkers is also observed. In addition to these findings, the nanomedicine successfully normalizes the elevated expression of GAPDH and mTOR induced by exposure to benzene. Further, the nanomedicine downregulates pro-survival components of the NF-kappa B pathway and upregulated P53 expression. Additionally, in the TRAIL pathway, it enhances the expression of pro-apoptotic players TRAIL and DR5 and downregulates the anti-apoptotic protein cFLIP.

CONCLUSIONS

Our data suggest that MSNPs loaded with caffeine, i.e., CcNP/nanomedicine, can potentially inhibit transformed cell proliferation and induce pro-apoptotic TRAIL machinery to counter benzene-induced leukemia. These results render our nanomedicine as a potentially excellent therapeutic agent against AML.

Magnetic Metal-Organic Framework-Based Nanoplatform with Platelet Membrane Coating as a Synergistic Programmed Cell Death Protein 1 Inhibitor against Hepatocellular Carcinoma

Programmed cell death protein 1 (PD-1) inhibitors are the most common immune-checkpoint inhibitors and considered promising drugs for hepatocellular carcinoma (HCC). However, in clinical settings, they have a low objective response rate (15%-20%) for patients with HCC; this is because of the insufficient level and activity of tumor-infiltrating T lymphocytes (TILs). The combined administration of oxymatrine (Om) and astragaloside IV (As) can increase the levels of TILs by inhibiting the activation of cancer-associated fibroblasts (CAFs) and improve the activity of TILs by enhancing their mitochondrial function. In the present study, we constructed a magnetic metal-organic framework (MOF)-based nanoplatform with platelet membrane (Pm) coating (PmMN@Om&As) to simultaneously deliver Om and As into the HCC microenvironment. We observed that PmMN@Om&As exhibited a high total drug-loading capacity (33.77 wt %) and good immune escape. Furthermore, it can target HCC tissues in a magnetic field and exert long-lasting effects. The HCC microenvironment accelerated the disintegration of PmMN@Om&As and the release of Om&As, thereby increasing the level and activity of TILs by regulating CAFs and the mitochondrial function of TILs. In addition, the carrier could synergize with Om&As by enhancing the oxygen consumption rate and proton efflux rate of TILs, thereby upregulating the mitochondrial function of TILs. Combination therapy with PmMN@Om&As and α-PD-1 resulted in a tumor suppression rate of 84.15% and prolonged the survival time of mice. Our study provides a promising approach to improving the antitumor effect of immunotherapy in HCC.

SIRPα controls CD47-dependent platelet clearance in mice and humans

Over the last decade, more data has revealed that increased surface expression of the "don't eat me" CD47 protein on cancer cells plays a role in immune evasion and tumor progression, with CD47 blockade emerging as a new therapy in immuno-oncology. CD47 is critical in regulating cell homeostasis and clearance, as binding of CD47 to the inhibitory receptor SIRPα can prevent phagocytosis and macrophage-mediated cell clearance. The purpose of this study was to examine the role of the CD47-SIRPα signal in platelet homeostasis and clearance. Therapeutic reagents targeting the CD47-SIRPα axis are very promising for treatment of hematologic malignancies and solid tumors, but lead to transient anemia or thrombocytopenia in a subset of patients. We found that platelet homeostatic clearance is regulated through the CD47-SIRPα axis and that therapeutic blockade to disrupt this interaction in mice and in humans has a significant impact on platelet levels. Furthermore, we identified genetic variations at the SIRPA locus that impact platelet levels in humans such that higher SIRPA gene expression is associated with higher platelet levels. SIRPA expression at either end of the normal range may affect clinical outcomes of treatment with anti-CD47 therapy.

A bio-inspired nanoparticle coating for vascular healing and immunomodulatory by cGMP-PKG and NF-kappa B signaling pathways

Drug-eluting stents (DESs) implantation is an effective method to tackle in-stent restenosis (ISR), which has been considered as an efficient treatment for coronary atherosclerosis. Although fruitful results have been achieved in treating coronary artery diseases (CAD), concern has arisen regarding the long-term safety and efficacy of DESs, primarily due to adverse events such as delayed re-endothelialization, persistent inflammatory response, and late stent thrombosis (LST). Taking inspiration from the immunomodulatory functions of camouflage strategies, this study designed a bio-inspired nanoparticle-coated stent. Briefly, the platelet membrane-coated poly (lactic-co-glycolic acid)/Rapamycin nanoparticles (PNP) were sprayed onto stents, forming a homogenous nanoparticle coating. The bilayer of poly (lactic-co-glycolic acid) (PLGA) and platelet membrane works synergistically to promote the sustained-release effect of rapamycin. In vitro studies revealed that the PNP-coated surfaces promoted the competitive adhesion of endothelia cells while inhibiting smooth muscle cells. Subsequent in vivo studies demonstrated that these surfaces expedite re-endothelialization and elicit immunomodulatory effects by regulating the cGMP-PKG and NF-kappa B signaling pathways, influencing the biosynthesis cofactors and immune system signaling. The study successfully deviced a novel and biomimetic drug-eluting stent system, unraveling its detailed functions and molecular mechanism of action for enhanced vascular healing.

CD47: The Next Frontier in Immune Checkpoint Blockade for Non-Small Cell Lung Cancer

The success of PD-1/PD-L1-targeted therapy in lung cancer has resulted in great enthusiasm for additional immunotherapies in development to elicit similar survival benefits, particularly in patients who do not respond to or are ineligible for PD-1 blockade. CD47 is an immunosuppressive molecule that binds SIRPα on antigen-presenting cells to regulate an innate immune checkpoint that blocks phagocytosis and subsequent activation of adaptive tumor immunity. In lung cancer, CD47 expression is associated with poor survival and tumors with EGFR mutations, which do not typically respond to PD-1 blockade. Given its prognostic relevance, its role in facilitating immune escape, and the number of agents currently in clinical development, CD47 blockade represents a promising next-generation immunotherapy for lung cancer. In this review, we briefly summarize how tumors disrupt the cancer immunity cycle to facilitate immune evasion and their exploitation of immune checkpoints like the CD47-SIRPα axis. We also discuss approved immune checkpoint inhibitors and strategies for targeting CD47 that are currently being investigated. Finally, we review the literature supporting CD47 as a promising immunotherapeutic target in lung cancer and offer our perspective on key obstacles that must be overcome to establish CD47 blockade as the next standard of care for lung cancer therapy.

Desialylated Platelet Clearance in the Liver is a Novel Mechanism of Systemic Immunosuppression

Platelets are small, versatile blood cells that are critical for hemostasis/thrombosis. Local platelet accumulation is a known contributor to proinflammation in various disease states. However, the anti-inflammatory/immunosuppressive potential of platelets has been poorly explored. Here, we uncovered, unexpectedly, desialylated platelets (dPLTs) down-regulated immune responses against both platelet-associated and -independent antigen challenges. Utilizing multispectral photoacoustic tomography, we tracked dPLT trafficking to gut vasculature and an exclusive Kupffer cell-mediated dPLT clearance in the liver, a process that we identified to be synergistically dependent on platelet glycoprotein Ibα and hepatic Ashwell-Morell receptor. Mechanistically, Kupffer cell clearance of dPLT potentiated a systemic immunosuppressive state with increased anti-inflammatory cytokines and circulating CD4+ regulatory T cells, abolishable by Kupffer cell depletion. Last, in a clinically relevant model of hemophilia A, presensitization with dPLT attenuated anti-factor VIII antibody production after factor VIII ( infusion. As platelet desialylation commonly occurs in daily-aged and activated platelets, these findings open new avenues toward understanding immune homeostasis and potentiate the therapeutic potential of dPLT and engineered dPLT transfusions in controlling autoimmune and alloimmune diseases.

Bio-Inspired Nanomaterials for Micro/Nanodevices: A New Era in Biomedical Applications

Exploring bio-inspired nanomaterials (BINMs) and incorporating them into micro/nanodevices represent a significant development in biomedical applications. Nanomaterials, engineered to imitate biological structures and processes, exhibit distinctive attributes such as exceptional biocompatibility, multifunctionality, and unparalleled versatility. The utilization of BINMs demonstrates significant potential in diverse domains of biomedical micro/nanodevices, encompassing biosensors, targeted drug delivery systems, and advanced tissue engineering constructs. This article thoroughly examines the development and distinctive attributes of various BINMs, including those originating from proteins, DNA, and biomimetic polymers. Significant attention is directed toward incorporating these entities into micro/nanodevices and the subsequent biomedical ramifications that arise. This review explores biomimicry's structure-function correlations. Synthesis mosaics include bioprocesses, biomolecules, and natural structures. These nanomaterials' interfaces use biomimetic functionalization and geometric adaptations, transforming drug delivery, nanobiosensing, bio-inspired organ-on-chip systems, cancer-on-chip models, wound healing dressing mats, and antimicrobial surfaces. It provides an in-depth analysis of the existing challenges and proposes prospective strategies to improve the efficiency, performance, and reliability of these devices. Furthermore, this study offers a forward-thinking viewpoint highlighting potential avenues for future exploration and advancement. The objective is to effectively utilize and maximize the application of BINMs in the progression of biomedical micro/nanodevices, thereby propelling this rapidly developing field toward its promising future.

Construction of micro-nano robots: living cells and functionalized biological cell membranes

Micro-nano robots have emerged as a promising research field with vast potential applications in biomedicine. The motor is the key component of micro-nano robot research, and the design of the motor is crucial. Among the most commonly used motors are those derived from living cells such as bacteria with flagella, sperm, and algal cells. Additionally, scientists have developed numerous self-adaptive biomimetic motors with biological functions, primarily cell membrane functionalized micromotors. This novel type of motor exhibits remarkable performance in complex media. This paper provides a comprehensive review of the structure and performance of micro-nano robots that utilize living cells and functionalized biological cell membranes. We also discuss potential practical applications of these mirco-nano robots as well as potential challenges that may arise in future development.

Chimeric Peptide Engineered Bioregulator for Metastatic Tumor Immunotherapy through Macrophage Polarization and Phagocytosis Restoration

Tumor-associated macrophages (TAMs) are the most abundant immune cells in solid tumor tissues, which restrict antitumor immunity by releasing tumor-supporting cytokines and attenuating phagocytosis behaviors. In this work, a chimeric peptide engineered bioregulator (ChiP-RS) is constructed for tumor immunotherapy through macrophage polarization and phagocytosis restoration. ChiP-RS is fabricated by utilizing macrophage-targeting chimeric peptide (ChiP) to load Toll-like receptor agonists (R848) and Src homology 2 (SH2) domain-containing protein tyrosine phosphatase 2 (SHP-2) inhibitor (SHP099). Among which, ChiP-RS prefers to be internalized by TAMs, repolarizing M2 macrophages into M1 macrophages to reverse the immunosuppressive microenvironment. In addition, SHP-2 can be downregulated to promote phagocytotic elimination behaviors of M1 macrophages, which will also activate T cell-based antitumor immunity for metastatic tumor therapy. In vitro and in vivo findings demonstrate a superior suppression effect of ChiP-RS against metastatic tumors without systemic side effects. Such a simple but effective nanoplatform provides sophisticated synergism for immunotherapy, which may facilitate the development of translational nanomedicine for metastatic tumor treatment.

Efferocytosis-inspired nanodrug treats sepsis by alleviating inflammation and secondary immunosuppression

Uncontrolled inflammation storm induced by sepsis may lead to severe organ dysfunction and secondary immunosuppression, which is one of the main reasons for high mortality and prolonged hospitalization of septic patients. However, there is a lack of effective treatments for it at present. Here, we report an efferocytosis-inspired nanodrug (BCN@M) to treat sepsis and secondary immunosuppression via regulating the macrophage function. Bioactive molecular curcumin was loaded with bovine serum albumin and then coated with the damaged erythrocyte membrane derived from septic mice. It was found that the septic erythrocytes promoted the efferocytosis signal and BCN@M uptake efficiency by macrophages. The well-constructed BCN@M nanodrug reduced the hyperinflammation in sepsis and restored the bacterial clearance ability of macrophage in the secondary immunosuppression state. This study highlights BCN@M as an efferocytosis-inspired nanodrug to alleviate hyperinflammation and secondary immunosuppression of sepsis.

Applications of injectable hemostatic materials in wound healing: principles, strategies, performance requirements, and future perspectives

Uncontrolled traumatic bleeding can lead to death due to excessive blood loss within minutes. Early intervention is crucial to save lives, making timely and effective hemostasis is a major global challenge. Injectable hemostatic materials (IHMs) have been proposed to improve the effectiveness of hemostasis, facilitate wound healing, and enhance survival rates in emergency situations. The superior hemostatic performance of IHMs has garnered significant attention. However, there are relatively few comprehensive reviews on IHMs. This paper aims to provide a comprehensive review of the latest research progress on IHMs in recent years. Firstly, the physiological hemostatic process and the underlying principles of hemostasis are analyzed. Subsequently, the synthesis strategies for different IHMs are discussed. The performance requirements of IHMs are then summarized, including high efficiency, biocompatibility, degradability, manipulability, stability and antibacterial ability. Finally, the development prospects and challenges of IHMs are presented. This review serves as a necessary and systematic summary of IHMs, providing a valuable reference for the development of new high-performance hemostatic materials and their practical clinical applications.

Surface modification potentials of cell membrane-based materials for targeted therapies: a chemotherapy-focused review

Nanotechnology has significant potential for cancer management at all stages, including prevention, diagnosis and treatment. In therapeutic applications, nanoparticles (NPs) have biological stability, targeting and body-clearance issues. To overcome these difficulties, biomimetic or cell membrane-coating methods using immune cell membranes are advised. Macrophage or neutrophil cell membrane-coated NPs may impede cancer progression in malignant tissue. Immune cell surface proteins and their capacity to maintain activity after membrane extraction and NP coating determine NP functioning. Immune cell surface proteins may offer NPs higher cellular interactions, blood circulation, antigen recognition for targeting, progressive drug release and reduced in vivo toxicity. This article examines nano-based systems with immune cell membranes, their surface modification potential, and their application in cancer treatment.

Exploring the Microfluidic Production of Biomimetic Hybrid Nanoparticles and Their Pharmaceutical Applications

Nanomedicines have made remarkable advances in recent years, addressing the limitations of traditional therapy and treatment methods. Due to their improved drug solubility, stability, precise delivery, and ability to target specific sites, nanoparticle-based drug delivery systems have emerged as highly promising solutions. The successful interaction of nanoparticles with biological systems, on the other hand, is dependent on their intentional surface engineering. As a result, biomimetic nanoparticles have been developed as novel drug carriers. In-depth knowledge of various biomimetic nanoparticles, their applications, and the methods used for their formulation, with emphasis on the microfluidic production technique, is provided in this review. Microfluidics has emerged as one of the most promising approaches for precise control, high reproducibility, scalability, waste reduction, and faster production times in the preparation of biomimetic nanoparticles. Significant advancements in personalized medicine can be achieved by harnessing the benefits of biomimetic nanoparticles and leveraging microfluidic technology, offering enhanced functionality and biocompatibility.

Platelet membrane-coated alterbrassicene A nanoparticle inhibits calcification of the aortic valve by suppressing phosphorylation P65 NF-κB

Rationale: Calcific aortic valve disease (CAVD) is a leading cause of cardiovascular mortality and morbidity with increasing prevalence and incidence. The pathobiology of CAVD involves valvular fibrocalcification, and osteogenic and fibrogenic activities are elevated in aortic valve interstitial cells (VICs) from diseased valves. It has been demonstrated that activated NF-κB pathway was present in the early stage of CAVD process. There is currently no effective clinical drugs targeting NF-κB pathway for CAVD treatment. Therefore, it is of great clinical significance to seek effective treatments for valve calcification. Methods: In this study, we established immortal human valve interstitial cells (im-hVICs) with pGMLV-SV40T-puro lentivirus. Alizarin red staining and western blotting were performed to evaluate the calcification of immortal VICs supplemented with different compounds. The natural fusicoccane diterpenoid alterbrassicene A (ABA) was found to have potential therapeutic functions. Ribonucleic acid sequencing was used to identify the potential target of ABA. Platelet membrane-coated nanoparticle of ABA (PNP-ABA) was fabricated and the IBIDI pump was used to evaluate the adhesion ability of PNP-ABA. Murine wire-induced aortic valve stenosis model was conducted for in vivo study of PNP-ABA. Results: The natural fusicoccane diterpenoid ABA was found to significantly reduce the calcification of human VICs during osteogenic induction via inhibiting the phosphorylation P65. Runt-related transcription factor 2 (Runx2) and bone morphogenetic protein-2 (BMP2) were down regulated with the treatment of ABA in human VICs. Additionally, molecular docking results revealed that ABA bound to RelA (P65) protein. Phosphorylation of P65 (Ser536) was alleviated by ABA treatment, as well as the nuclear translocation of P65 during osteogenic induction in human VICs. Alizarin red staining showed that ABA inhibited osteogenic differentiation of VICs in a dose-dependent manner. PNP-ABA attenuated aortic valve calcification in murine wire-induced aortic valve stenosis model in vivo. Conclusions: The establishment of im-hVICs provides a convenient cell line for the study of CAVD. Moreover, our current research highlights a novel natural compound, ABA, as a promising candidate to prevent the progression of CAVD.

A MD Simulation Prediction for Regulation of N-Terminal Modification on Binding of CD47 to CD172a in a Force-Dependent Manner

Cancer cells can evade immune surveillance through binding of its transmembrane receptor CD47 to CD172a on myeloid cells. CD47 is recognized as a promising immune checkpoint for cancer immunotherapy inhibiting macrophage phagocytosis. N-terminal post-translated modification (PTM) via glutaminyl cyclase is a landmark event in CD47 function maturation, but the molecular mechanism underlying the mechano-chemical regulation of the modification on CD47/CD172a remains unclear. Here, we performed so-called "ramp-clamp" steered molecular dynamics (SMD) simulations, and found that the N-terminal PTM enhanced interaction of CD172a with CD47 by inducing a dynamics-driven contraction of the binding pocket of the bound CD172a, an additional constraint on CYS15 on CD47 significantly improved the tensile strength of the complex with or without PTM, and a catch bond phenomenon would occur in complex dissociation under tensile force of 25 pN in a PTM-independent manner too. The residues GLN52 and SER66 on CD172a reinforced the H-bonding with their partners on CD47 in responding to PTM, while ARG69 on CD172 with its partner on CD47 might be crucial in the structural stability of the complex. This work might serve as molecular basis for the PTM-induced function improvement of CD47, should be helpful for deeply understanding CD47-relevant immune response and cancer development, and provides a novel insight in developing of new strategies of immunotherapy targeting this molecule interaction.

Thrombocytopenia Independently Leads to Monocyte Immune Dysfunction

In addition to their well-studied hemostatic functions, platelets are immune cells. Platelets circulate at the interface between the vascular wall and leukocytes, and transient platelet-leukocyte complexes are found in both healthy and disease states, positioning platelets to provide physiologic cues of vascular health and injury. Roles for activated platelets in inducing and amplifying immune responses have received an increasing amount of research attention, but our past studies also showed that normal platelet counts are needed in healthy conditions to maintain immune homeostasis. We have now found that thrombocytopenia (a low platelet count) leads to monocyte dysfunction, independent of the cause of thrombocytopenia, in a manner that is dependent on direct platelet-monocyte CD47 interactions that regulate monocyte immunometabolism and gene expression. Compared to monocytes from mice with normal platelet counts, monocytes from thrombocytopenic mice had increased toll-like receptor (TLR) responses, including increased IL-6 production. Furthermore, ex vivo co-incubation of resting platelets with platelet naïve bone marrow monocytes, induced monocyte metabolic programming and durable changes in TLR agonist responses. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-Seq) on monocytes from thrombocytopenic mice showed persistently open chromatin at LPS response genes and resting platelet interactions with monocytes induced histone methylation in a CD47 dependent manner. Using mouse models of thrombocytopenia and sepsis, normal platelet numbers were needed to limit monocyte immune dysregulation and IL6 expression in monocytes from human patients with sepsis also inversely correlated with patient platelet counts. Our studies demonstrate that in healthy conditions, resting platelets maintain monocyte immune tolerance by regulating monocyte immunometabolic processes that lead to epigenetic changes in TLR-related genes. This is also the first demonstration of sterile cell interactions that regulate of innate immune-metabolism and monocyte pathogen responses.

Blocking the CD47-SIRPα interaction reverses the disease phenotype in a polycythemia vera mouse model

Polycythemia vera (PV) is a hematopoietic stem cell neoplasm driven by somatic mutations in JAK2, leading to increased red blood cell (RBC) production uncoupled from mechanisms that regulate physiological erythropoiesis. At steady-state, bone marrow macrophages promote erythroid maturation, whereas splenic macrophages phagocytose aged or damaged RBCs. The binding of the anti-phagocytic ("don't eat me") CD47 ligand expressed on RBCs to the SIRPα receptor on macrophages inhibits phagocytic activity protecting RBCs from phagocytosis. In this study, we explore the role of the CD47-SIRPα interaction on the PV RBC life cycle. Our results show that blocking CD47-SIRPα in a PV mouse model due to either anti-CD47 treatment or loss of the inhibitory SIRPα-signal corrects the polycythemia phenotype. Anti-CD47 treatment marginally impacted PV RBC production while not influencing erythroid maturation. However, upon anti-CD47 treatment, high-parametric single-cell cytometry identified an increase of MerTK+ splenic monocyte-derived effector cells, which differentiate from Ly6C^hi monocytes during inflammatory conditions, acquire an inflammatory phagocytic state. Furthermore, in vitro, functional assays showed that splenic JAK2 mutant macrophages were more "pro-phagocytic," suggesting that PV RBCs exploit the CD47-SIRPα interaction to escape innate immune attacks by clonal JAK2 mutant macrophages.

Biomimicry in nanotechnology: a comprehensive review

Biomimicry has been utilized in many branches of science and engineering to develop devices for enhanced and better performance. The application of nanotechnology has made life easier in modern times. It has offered a way to manipulate matter and systems at the atomic level. As a result, the miniaturization of numerous devices has been possible. Of late, the integration of biomimicry with nanotechnology has shown promising results in the fields of medicine, robotics, sensors, photonics, etc. Biomimicry in nanotechnology has provided eco-friendly and green solutions to the energy problem and in textiles. This is a new research area that needs to be explored more thoroughly. This review illustrates the progress and innovations made in the field of nanotechnology with the integration of biomimicry.

Engineered biomembrane-derived nanoparticles for nanoscale theranostics

Currently, biological membrane-derived nanoparticles (NPs) have shown enormous potential as drug delivery vehicles due to their outstanding biomimetic properties. To make these NPs more adaptive to complex biological systems, some methods have been developed to modify biomembranes and endow them with more functions while preserving their inherent natures. In this review, we introduce five common approaches used for biomembrane decoration: membrane hybridization, the postinsertion method, chemical methods, metabolism engineering and gene engineering. These methods can functionalize a series of biomembranes derived from red blood cells, white blood cells, tumor cells, platelets, exosomes and so on. Biomembrane engineering could markedly facilitate the targeted drug delivery, treatment and diagnosis of cancer, inflammation, immunological diseases, bone diseases and Alzheimer's disease. It is anticipated that these membrane modification techniques will advance biomembrane-derived NPs into broader applications in the future.

Targeting drugs to tumours using cell membrane-coated nanoparticles

Traditional cancer therapeutics, such as chemotherapies, are often limited by their non-specific nature, causing harm to non-malignant tissues. Over the past several decades, nanomedicine researchers have sought to address this challenge by developing nanoscale platforms capable of more precisely delivering drug payloads. Cell membrane-coated nanoparticles (CNPs) are an emerging class of nanocarriers that have demonstrated considerable promise for biomedical applications. Consisting of a synthetic nanoparticulate core camouflaged by a layer of naturally derived cell membranes, CNPs are adept at operating within complex biological environments; depending on the type of cell membrane utilized, the resulting biomimetic nanoformulation is conferred with several properties typically associated with the source cell, including improved biocompatibility, immune evasion and tumour targeting. In comparison with traditional functionalization approaches, cell membrane coating provides a streamlined method for creating multifunctional and multi-antigenic nanoparticles. In this Review, we discuss the history and development of CNPs as well as how these platforms have been used for cancer therapy. The application of CNPs for drug delivery, phototherapy and immunotherapy will be described in detail. Translational efforts are currently under way and further research to address key areas of need will ultimately be required to facilitate the successful clinical adoption of CNPs.

Cell-Derived Vesicles for Nanoparticles' Coating: Biomimetic Approaches for Enhanced Blood Circulation and Cancer Therapy

Cancer nanomedicines are designed to encapsulate different therapeutic agents, prevent their premature release, and deliver them specifically to cancer cells, due to their ability to preferentially accumulate in tumor tissue. However, after intravenous administration, nanoparticles immediately interact with biological components that facilitate their recognition by the immune system, being rapidly removed from circulation. Reports show that less than 1% of the administered nanoparticles effectively reach the tumor site. This suboptimal pharmacokinetic profile is pointed out as one of the main factors for the nanoparticles' suboptimal therapeutic effectiveness and poor translation to the clinic. Therefore, an extended blood circulation time may be crucial to increase the nanoparticles' chances of being accumulated in the tumor and promote a site-specific delivery of therapeutic agents. For that purpose, the understanding of the forces that govern the nanoparticles' interaction with biological components and the impact of the physicochemical properties on the in vivo fate will allow the development of novel and more effective nanomedicines. Therefore, in this review, the nano-bio interactions are summarized. Moreover, the application of cell-derived vesicles for extending the blood circulation time and tumor accumulation is reviewed, focusing on the advantages and shortcomings of each cell source.

Inhibition of the CD47-SIRPα axis for cancer therapy: A systematic review and meta-analysis of emerging clinical data

CD47-SIRPα interaction acts as a "don't eat me" signal and is exploited by cancer to downregulate innate and adaptive immune surveillance. There has been intense interest to develop a mechanism of blockade, and we aimed to analyze the emerging data from early clinical trials. We performed a systematic review and meta-analysis of relevant databases and conference abstracts including clinical trials using CD47 and/or SIRPα inhibitors in cancer treatment. Nonlinear mixed models were applied for comparison of response and toxicity. We retrieved 317 articles, 24 of which were eligible. These included 771 response-evaluable patients with hematologic (47.1%) and solid tumors (52.9%). Of these, 6.4% experienced complete response, 10.4% partial response, and 26.1% stable disease for a 16.7% objective response rate (ORR), 42.8% disease control rate, and 4.8-month median duration of response. ORR was significantly higher for hematologic cancers (25.3%) than solid cancers (9.1%, p=0.042). Comparing by mechanism, seven CD47 monoclonal antibodies (mAbs) and six selective SIRPα blockers were given alone or combined with checkpoint inhibitors, targeted therapy, and/or chemotherapy. In solid cancers, selective SIRPα blockade showed a higher ORR (16.2%) than anti-CD47 mAbs (2.8%, p=0.079), which was significant for combination therapies (ORR 28.3% vs 3.0%, respectively, p=0.010). Responses were seen in head and neck, colorectal, endometrial, ovarian, hepatocellular, non-small cell lung, and HER2+gastroesophageal cancers. Dose-limiting toxicity (DLT) was seen in 3.3% of patients (5.4% anti-CD47 mAbs, 1.4% selective SIRPα blockers; p=0.01). The frequency of treatment-related adverse events (TRAEs) ≥grade 3 was 18.0%, similar between the two groups (p=0.082), and mostly laboratory abnormalities. For anti-CD47 mAbs, the most common toxicities included grade 1-2 fatigue (27.2%), headache (21.0%), and anemia (20.5%). For selective SIRPα blockers, these included grade 1-2 infusion reaction (23.1%) and fatigue (15.8%). Anti-CD47 mAbs were significantly more likely than selective SIRPα blockers to cause grade 1-2 fever, chills, nausea/vomiting, headache, and anemia. In conclusion, combination therapies using selective SIRPα blockade had higher response rates in solid tumors than anti-CD47 mAb combinations. Hematologic changes were the main TRAEs, and selective SIRPα blockers seemed to have a better grade 1-2 toxicity profile. Treatment was well-tolerated with minimal DLTs.

A ROS-responsive biomimetic nano-platform for enhanced chemo-photodynamic-immunotherapy efficacy

Due to the complex bloodstream components, tumor microenvironment and tumor heterogeneity, traditional nanoparticles have a limited effect (low drug delivery efficiency and poor penetration to the deeper tumor) on eradicating tumors. To solve these challenges, novel platelet membrane-coated nanoparticles (PCDD NPs) were constructed for combined chemo-photodynamic- and immunotherapy of melanoma. The platelet membrane imparted the PCDD nanoparticles with an excellent long circulation effect and tumor targeting ability, which solved the issues of low drug delivery efficiency. After reaching the tumor cells, it releases the drug-loaded CDD micelles, becoming positively charged and facilitating the deep penetration of tumors. Cytotoxic and apoptosis experiments showed that PCDD nanoparticles have the strongest tumor cell killing ability. Based on the excellent results in vitro, PCDD was used to assess anti-tumor and distal tumor inhibition in rat models. The results revealed that the PCDD combined PDT, immunotherapy and chemotherapy could not only inhibit the primary tumor growth (inhibition rate: 92.0%) but also suppress the distant tumor growth (inhibition rate: 90.7%) and lung metastasis, which is far more effective compared to the commercial Taxotere®. Exploration of the molecular mechanism showed that in vivo immune response induced an increase in positive immune responders, suppressed negative immune suppressors, and established an inflammatory tumor immune environment, leading to excellent results in tumor suppression and lung metastasis. In conclusion, this novel multifunctional PCDD nanoparticle is a promising platform for tumor combined chemotherapy, photodynamic therapy (PDT) and immunotherapy.

Red Phosphorus/P25 Nanophotosensitizers Coated with Platelet Membrane for Enhancing Cancer Cells Photodynamic Therapy

Photodynamic therapy (PDT), which uses targeted photosensitizing drugs, has been regarded as a promising method for cancer therapy. In the present study, photosensitizer red phosphorus modified P25 nanophotosensitizers (P25-RP) were generated, which were coated with platelet membrane (P25-RP@PLT) extracted from platelet rich plasma. The biocompatibility of P25-RP was demonstrated by cell counting kit-8 (CCK-8) and optical microscope assay, more than 93 % cells in the concentration of 100 μg/ml of P25-RP suspension after co-incubation for 24 h were still kept alive. The antitumor performance of P25-RP@PLT was evaluated via CCK-8 assay, flow cytometry and fluorescence staining of live/dead cells. The experiment results showed that P25-RP@PLT could ablate 55 % malignant tumor cells upon laser irradiation within 5 min, which was 10 % higher than P25-RP alone against cancer cells. Mechanistically, the cancer cell toxicity of P25-RP@PLT nanophotosensitizers was attributed to its heterojunction structure that broadens the absorption spectra, whereas PLT membrane coating technology allows for immune escape and selective adhesion capacity to cancer cells. This work provided a novel pathway on the design of novel visible-light-driven photosensitizer for cancer therapy.

Design principles of bioinspired interfaces for biomedical applications in therapeutics and imaging

In the past two decades, we have witnessed rapid developments in nanotechnology, especially in biomedical applications such as drug delivery, biosensing, and bioimaging. The most commonly used nanomaterials in biomedical applications are nanoparticles, which serve as carriers for various therapeutic and contrast reagents. Since nanomaterials are in direct contact with biological samples, biocompatibility is one of the most important issues for the fabrication and synthesis of nanomaterials for biomedical applications. To achieve specific recognition of biomolecules for targeted delivery and biomolecular sensing, it is common practice to engineer the surfaces of nanomaterials with recognition moieties. This mini-review summarizes different approaches for engineering the interfaces of nanomaterials to improve their biocompatibility and specific recognition properties. We also focus on design strategies that mimic biological systems such as cell membranes of red blood cells, leukocytes, platelets, cancer cells, and bacteria.

Targeting macrophages in hematological malignancies: recent advances and future directions

Emerging evidence indicates that the detection and clearance of cancer cells via phagocytosis induced by innate immune checkpoints play significant roles in tumor-mediated immune escape. The most well-described innate immune checkpoints are the "don't eat me" signals, including the CD47/signal regulatory protein α axis (SIRPα), PD-1/PD-L1 axis, CD24/SIGLEC-10 axis, and MHC-I/LILRB1 axis. Molecules have been developed to block these pathways and enhance the phagocytic activity against tumors. Several clinical studies have investigated the safety and efficacy of CD47 blockades, either alone or in combination with existing therapy in hematological malignancies, including myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and lymphoma. However, only a minority of patients have significant responses to these treatments alone. Combining CD47 blockades with other treatment modalities are in clinical studies, with early results suggesting a synergistic therapeutic effect. Targeting macrophages with bispecific antibodies are being explored in blood cancer therapy. Furthermore, reprogramming of pro-tumor macrophages to anti-tumor macrophages, and CAR macrophages (CAR-M) demonstrate anti-tumor activities. In this review, we elucidated distinct types of macrophage-targeted strategies in hematological malignancies, from preclinical experiments to clinical trials, and outlined potential therapeutic approaches being developed.

CD47: Beyond an immune checkpoint in cancer treatment

The transmembrane protein, CD47, is recognized as an important innate immune checkpoint, and CD47-targeted drugs have been in development with the aim of inhibiting the interaction between CD47 and the regulatory glycoprotein SIRPα, for antitumor immunotherapy. Further, CD47 mediates other essential functions such as cell proliferation, caspase-independent cell death (CICD), angiogenesis and other integrin-activation-dependent cell phenotypic responses when bound to thrombospondin-1 (TSP-1) or other ligands. Mounting strategies that target CD47 have been developed in pre-clinical and clinical trials, including antibodies, small molecules, siRNAs, and peptides, and some of them have shown great promise in cancer treatment. Herein, the authors endeavor to provide a retrospective of ligand-mediated CD47 regulatory mechanisms, their roles in controlling antitumor intercellular and intracellular signal transduction, and an overview of CD47-targetd drug design.

Immune Checkpoint Inhibition in Acute Myeloid Leukemia and Myelodysplastic Syndromes

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many solid tumors, with limited progress made in the area of myeloid malignancies. The low mutational burden of acute myeloid leukemia (AML) is one potential reason behind the lack of activity of T-cell harnessing ICIs, particularly CTLA-4 and PD-1 inhibitors. Innate immune checkpoints play a critical role in the immune escape of AML and myelodysplastic syndromes (MDS). The CD47 targeting agent, magrolimab, has shown promising activity when combined with azacitidine in early phase trials conducted in AML and higher-risk MDS, especially among patients harboring a TP53 mutation. Similarly, sabatolimab (an anti-TIM-3 monoclonal antibody) plus hypomethylating agents have shown durable responses in higher-risk MDS and AML in early clinical trials. Randomized trials are currently ongoing to confirm the efficacy of these agents. In this review, we will present the current progress and future directions of immune checkpoint inhibition in AML and MDS.

Targeting the CD47-SIRPα Innate Immune Checkpoint to Potentiate Antibody Therapy in Cancer by Neutrophils

Simple Summary

Immunotherapy aims to engage various immune cells in the elimination of cancer cells. Neutrophils are the most abundant leukocytes in the circulation and have unique mechanisms by which they can kill cancer cells opsonized by antibodies. However, neutrophil effector functions are limited by the inhibitory receptor SIRPα, when it interacts with CD47. The CD47 protein is expressed on all cells in the body and acts as a ‘don’t eat me’ signal to prevent tissue damage. Cancer cells can express high levels of CD47 to circumvent tumor elimination. Thus, blocking the interaction between CD47 and SIRPα may enhance anti-tumor effects by neutrophils in the presence of tumor-targeting monoclonal antibodies. In this review, we discuss CD47-SIRPα as an innate immune checkpoint on neutrophils and explore the preliminary results of clinical trials using CD47-SIRPα blocking agents.

Abstract

In the past 25 years, a considerable number of therapeutic monoclonal antibodies (mAb) against a variety of tumor-associated antigens (TAA) have become available for the targeted treatment of hematologic and solid cancers. Such antibodies opsonize cancer cells and can trigger cytotoxic responses mediated by Fc-receptor expressing immune cells in the tumor microenvironment (TME). Although frequently ignored, neutrophils, which are abundantly present in the circulation and many cancers, have demonstrated to constitute bona fide effector cells for antibody-mediated tumor elimination in vivo. It has now also been established that neutrophils exert a unique mechanism of cytotoxicity towards antibody-opsonized tumor cells, known as trogoptosis, which involves Fc-receptor (FcR)-mediated trogocytosis of cancer cell plasma membrane leading to a lytic/necrotic type of cell death. However, neutrophils prominently express the myeloid inhibitory receptor SIRPα, which upon interaction with the ‘don’t eat me’ signal CD47 on cancer cells, limits cytotoxicity, forming a mechanism of resistance towards anti-cancer antibody therapeutics. In fact, tumor cells often overexpress CD47, thereby even more strongly restricting neutrophil-mediated tumor killing. Blocking the CD47-SIRPα interaction may therefore potentiate neutrophil-mediated antibody-dependent cellular cytotoxicity (ADCC) towards cancer cells, and various inhibitors of the CD47-SIRPα axis are now in clinical studies. Here, we review the role of neutrophils in antibody therapy in cancer and their regulation by the CD47-SIRPα innate immune checkpoint. Moreover, initial results of CD47-SIRPα blockade in clinical trials are discussed.

Cell Membrane-Derived Vesicle: A Novel Vehicle for Cancer Immunotherapy

As nano-sized materials prepared by isolating, disrupting and extruding cell membranes, cellular vesicles are emerging as a novel vehicle for immunotherapeutic drugs to activate antitumor immunity. Cell membrane-derived vesicles inherit the surface characteristics and functional properties of parental cells, thus having superior biocompatibility, low immunogenicity and long circulation. Moreover, the potent antitumor effect of cellular vesicles can be achieved through surface modification, genetic engineering, hybridization, drug encapsulation, and exogenous stimulation. The capacity of cellular vesicles to combine drugs of different compositions and functions in physical space provides a promising vehicle for combinational immunotherapy of cancer. In this review, the latest advances in cellular vesicles as vehicles for combinational cancer immunotherapy are systematically summarized with focuses on manufacturing processes, cell sources, therapeutic strategies and applications, providing an insight into the potential and existing challenges of using cellular vesicles for cancer immunotherapy.

Targeting Myeloid Checkpoint Molecules in Combination With Antibody Therapy: A Novel Anti-Cancer Strategy With IgA Antibodies?

Immunotherapy with therapeutic antibodies has shown a lack of durable responses in some patients due to resistance mechanisms. Checkpoint molecules expressed by tumor cells have a deleterious impact on clinical responses to therapeutic antibodies. Myeloid checkpoints, which negatively regulate macrophage and neutrophil anti-tumor responses, are a novel type of checkpoint molecule. Myeloid checkpoint inhibition is currently being studied in combination with IgG-based immunotherapy. In contrast, the combination with IgA-based treatment has received minimal attention. IgA antibodies have been demonstrated to more effectively attract and activate neutrophils than their IgG counterparts. Therefore, myeloid checkpoint inhibition could be an interesting addition to IgA treatment and has the potential to significantly enhance IgA therapy.

Biomimetic Nanotherapeutics: Employing Nanoghosts to fight Melanoma

Melanoma is a cancer of melanocytes present at the basal layer of the skin. Nanomedicine has armed us with competent platform to manage such fatal neoplastic diseases. Nevertheless, it suffers from numerous pitfalls such as rapid clearance and opsonization of surface-functionalized carriers, biocompatibility and idiopathic reactions which could be difficult to predict in the patient. Biomimetic approach, a novel step towards personalized medicine bridges these drawbacks by employing endogenous cell membranes to traverse physiological barriers. Camouflaged carriers coated with natural cell membranes possess unique characteristics such as high circulatory periods, and the absence of allogenic and xenogenic responses. Proteins residing on the cell membranes render a diverse range of utilities to the coated nanoparticles including natural efficiency to identify cellular targets, homologous targeting, reticuloendothelial system evasion, biocompatibility and reduced adverse and idiopathic effects. In the present article, we have focused on cell membrane camouflaged nanocarriers for melanoma management. We have discussed various types of biomimetic systems, their processing and coating approaches, and their characterization. We have also enumerated novel avenues in melanoma treatment and the combination of biomimetic systems with smart nanoparticulate systems with the potential to bring breakthroughs in the near future. Additionally, immunotherapy-based biomimetic systems to combat melanoma have been highlighted. Hurdles towards clinical translation and ways to overcome them have been explained in detail.

Applications of Extracellular Vesicles in Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a localized expansion of the abdominal aorta which can lead to lethal complication as the rupture of aortic wall. Currently there is still neither competent method to predict the impending rupture of aneurysm, nor effective treatment to arrest the progression of small and asymptomatic aneurysms. Accumulating evidence has confirmed the crucial role of extracellular vesicles (EVs) in the pathological course of AAA, acting as important mediators of intercellular communication. Given the advantages of intrinsic targeting properties, lower toxicity and fair stability, EVs show great potential to serve as biomarkers, therapeutic agents and drug delivery carriers. However, EV therapies still face several major challenges before they can be applied clinically, including off-target effect, low accumulation rate and rapid clearance by mononuclear phagocyte system. In this review, we first illustrate the roles of EV in the pathological process of AAA and evaluate its possible clinical applications. We also identify present challenges for EV applications, highlight different strategies of EV engineering and constructions of EV-like nanoparticles, including EV display technology and membrane hybrid technology. These leading-edge techniques have been recently employed in multiple cardiovascular diseases and their promising application in the field of AAA is discussed.

Targeted delivery of fat extract by platelet membrane-cloaked nanocarriers for the treatment of ischemic stroke

BACKGROUND

Our previous studies suggest that human fat extract (FE) contains a variety of angiogenic factors and may provide an alternative treatment option for stroke. However, the therapeutic effect is largely limited due to its short half-life, and inaccurate targeting.

RESULTS

Herein, we leverage the targeting abilities of platelets (PLTs) to the lesion area of stroke and Arg-Gly-Asp (RGD) peptides to the angiogenic blood vessels to develop a biomimetic nanocarrier that capable of delivering FE precisely to treat stroke. The biomimetic nanocarriers are comprised of FE-encapsulated PLGA (poly(lactic-co-glycolic acid)) core enclosed by RGD peptides decorated plasma membrane of PLTs, namely RGD-PLT@PLGA-FE. We found that RGD-PLT@PLGA-FE not only targeted damaged and inflamed blood vessels but also achieved rapid accumulation in the lesion area of ischemic brain. In addition, RGD-PLT@PLGA-FE kept a sustained release behavior of FE at the lesion site, effectively increased its half-life and promoted angiogenesis and neurogenesis with delivering neurotrophic factors including BDNF, GDNF and bFGF to the brain, that ultimately resulted in blood flow increase and neurobehavioral recovery.

CONCLUSIONS

In conclusion, our study provides a new strategy to design a biomimetic system for FE delivery and it is a promising modality for stroke therapy.

Endothelial SIRPα signaling controls VE-cadherin endocytosis for thymic homing of progenitor cells

Thymic homing of hematopoietic progenitor cells (HPCs) is tightly regulated for proper T cell development. Previously we have identified a subset of specialized thymic portal endothelial cells (TPECs), which is important for thymic HPC homing. However, the underlying molecular mechanism still remains unknown. Here, we found that signal regulatory protein alpha (SIRPα) is preferentially expressed on TPECs. Disruption of CD47-SIRPα signaling in mice resulted in reduced number of thymic early T cell progenitors (ETPs), impaired thymic HPC homing, and altered early development of thymocytes. Mechanistically, Sirpa-deficient ECs and Cd47-deficient bone marrow progenitor cells or T lymphocytes demonstrated impaired transendothelial migration (TEM). Specifically, SIRPα intracellular ITIM motif-initiated downstream signaling in ECs was found to be required for TEM in an SHP2- and Src-dependent manner. Furthermore, CD47 signaling from migrating cells and SIRPα intracellular signaling were found to be required for VE-cadherin endocytosis in ECs. Thus, our study reveals a novel role of endothelial SIRPα signaling for thymic HPC homing for T cell development.

Nanostructured particles assembled from natural building blocks for advanced therapies

Advanced treatments based on immune system manipulation, gene transcription and regulation, specific organ and cell targeting, and/or photon energy conversion have emerged as promising therapeutic strategies against a range of challenging diseases. Naturally derived macromolecules (e.g., proteins, lipids, polysaccharides, and polyphenols) have increasingly found use as fundamental building blocks for nanostructured particles as their advantageous properties, including biocompatibility, biodegradability, inherent bioactivity, and diverse chemical properties make them suitable for advanced therapeutic applications. This review provides a timely and comprehensive summary of the use of a broad range of natural building blocks in the rapidly developing field of advanced therapeutics with insights specific to nanostructured particles. We focus on an up-to-date overview of the assembly of nanostructured particles using natural building blocks and summarize their key scientific and preclinical milestones for advanced therapies, including adoptive cell therapy, immunotherapy, gene therapy, active targeted drug delivery, photoacoustic therapy and imaging, photothermal therapy, and combinational therapy. A cross-comparison of the advantages and disadvantages of different natural building blocks are highlighted to elucidate the key design principles for such bio-derived nanoparticles toward improving their performance and adoption. Current challenges and future research directions are also discussed, which will accelerate our understanding of designing, engineering, and applying nanostructured particles for advanced therapies.

Leveraging macrophages for cancer theranostics

As fundamental immune cells in innate and adaptive immunity, macrophages engage in a double-edged relationship with cancer. Dissecting the character of macrophages in cancer development facilitates the emergence of macrophages-based new strategies that encompass macrophages as theranostic targets/tools of interest for treating cancer. Herein, we provide a concise overview of the mixed roles of macrophages in cancer pathogenesis and invasion as a foundation for the review discussions. We survey the latest progress on macrophage-based cancer theranostic strategies, emphasizing two major strategies, including targeting the endogenous tumor-associated macrophages (TAMs) and engineering the adoptive macrophages to reverse the immunosuppressive environment and augment the cancer theranostic efficacy. We also discuss and provide insights on the major challenges along with exciting opportunities for the future of macrophage-based cancer theranostic approaches.