Glycan modification of glioblastoma-derived extracellular vesicles enhances receptor-mediated targeting of dendritic cells

Exosomes in treating Eye Diseases: Targeting strategies

Exosomes are lipid-based vesicles carrying bioactive molecules (nucleic acids, proteins, lipids) that mediate intercellular communication. Emerging research explores their potential as therapeutic delivery systems, with bioengineering approaches enhancing stability and efficacy for clinical translation. This review focuses on exosome applications in ocular diseases, particularly engineered targeting strategies, while addressing current limitations and future clinical prospects.

Role of cancer cell-derived exosomal glycoproteins in macrophage polarization

Cancer is a deadly disease marked by abnormal cell growth, proliferation, and metastasis-the spread of cancer from its origin to distant sites. A key factor in tumor progression is the tumor microenvironment (TME), which significantly influences tumor behavior and response to treatment. Within the TME, interactions between cancer cells and surrounding immune cells, particularly tumor-associated macrophages (TAMs), play a critical role in shaping immune responses. This review focuses on recent findings from a systematic PubMed search regarding cancer cell-derived exosomal glycoproteins and their role in modulating macrophage phenotypes. Tumor-derived exosomes, a type of extracellular vesicle (EV), carry glycoproteins-proteins with attached sugar chains-that can influence macrophage polarization. These glycoproteins can reprogram macrophages into either the M1 phenotype (proinflammatory and anti-tumor) or the M2 phenotype (anti-inflammatory and tumor-supportive). The M1 macrophages inhibit tumor progression, while M2 macrophages support tumor growth by promoting immune suppression and tissue remodeling. Understanding how exosomal glycoproteins drive this polarization offers critical insight into cancer immunology and may pave the way for novel therapeutic strategies targeting the TME.

Implications of glioblastoma-derived exosomes in modifying the immune system: state-of-the-art and challenges

Glioblastoma is a brain cancer with a poor prognosis. Failure of classical chemotherapy and surgical treatments indicates that new therapeutic approaches are needed. Among cell-free options, exosomes are versatile extracellular vesicles (EVs) that carry important cargo across barriers such as the blood-brain barrier (BBB) to their target cells. This makes exosomes an interesting option for the treatment of glioblastoma. Moreover, exosomes can comprise many therapeutic cargos, including lipids, proteins, and nucleic acids, sampled from special intercellular compartments of their origin cell. Cells exposed to various immunomodulatory stimuli can generate exosomes enriched in specific therapeutic molecules. Notably, the secretion of exosomes could modify the immune response in innate and adaptive immune systems. For instance, glioblastoma-associated exosomes (GBex) uptake by macrophages could influence macrophage dynamics (e.g., shifting CD markers expression). Expression of critical immunoregulatory proteins such as cytotoxic T-lymphocyte antigen-1 (CTLA1) and programmed death-1 (PD-1) on GBex indicates the direct crosstalk of these nano-size vesicles with the immune system. The present study reviews the role of exosomes in immune system cells, including B cells, T cells, natural killer (NK) cells, and dendritic cells (DCs), as well as novel technologies in the field.

Carbohydrate sulfation as a critical modulator of siglec-sialoglycan interactions

Siglecs are sialic acid-binding immunomodulatory receptors that regulate immune homeostasis. Abnormal alterations in sialic acid-containing glycans (sialoglycans) on tissues or cells are key drivers of various diseases, including cancer, neurodegenerative disorders, allergies, and autoimmune diseases. Consequently, the role of Siglecs as immune checkpoints has gained increasing attention. To better understand Siglec biology, comprehensive approaches have been employed to elucidate Siglec ligands, including chemical synthesis for glycan microarrays and genetic manipulation of glycosyltransferases for understanding their biosynthesis process. These efforts have revealed that carbohydrate sulfation, catalyzed by carbohydrate sulfotransferases (CHSTs), fine-tunes Siglec-sialoglycan interactions by enhancing binding affinities. This review summarizes the latest insights into sulfated sialoglycan ligands for individual Siglecs.

A strategy for synergistic enhancement of immune circulation in head and neck squamous cell carcinoma by novel nucleic acid drug therapy and immunotherapy

Studies have shown that in the pathogenesis of head and neck squamous cell carcinoma, immune circulation obstruction caused by various factors including metabolic abnormalities, gene mutations, and matrix barrier, is a critical factor for the induction of tumor development and progression. Therefore, the immunotherapy strategy of killing head and neck squamous cell carcinoma cells by an enhanced immune circulation mechanism has attracted much attention. In addition, the rapid development of new nucleic acid drug therapy, such as mRNA, oligonucleotide and small guide RNA (sgRNA), has taken immunotherapy of head and neck squamous cell carcinoma (immune checkpoint inhibitors, tumor vaccines, cellular immunotherapy, cytokines and adjuvants, etc.) to a new level. The combination of nucleic acid therapy with immunotherapy developed for its therapeutic properties has brought a new direction for the diagnosis and treatment of head and neck squamous cell carcinoma, and the combination of the two has had considerable curative effect to patients with refractory/recurrent head and neck squamous cell carcinoma. In this review, we summarized the latest progress of nucleic acid therapy applied to conventional immunotherapy for head and neck squamous cell carcinoma, discussed its mechanism of action and efficacy, and looked into the future development trend.

A New Strategy to Functionalize Exosomes via Enzymatic Engineering of Surface Glycans and its Application to Profile Exosomal Glycans and Endocytosis

Exosomes are membrane-enclosed nanoparticles secreted by cells to mediate intercellular communication. Hence, functionalized exosomes are powerful tools in biology and medicine, and efficient methods to functionalize exosomes are highly desired. In this work, a novel approach is developed to modify and functionalize exosomes based on enzymatic engineering of their surface glycans. It employs a sialyltransferase and an azide-modified sialyl donor to enzymatically install azido-sialic acids onto exosomal glycans. The azide tags serve as universal molecular handles to attach various probes, e.g., biotin, protein, fluorophore, etc., by simple and biocompatible click chemistry. This approach is easy and effective, and the modified exosomes are readily retrieved from the plate, enabling the production of functional exosomes in practical scales for various studies and applications. The functionalized exosomes obtained are employed to profile exosomal glycans, disclosing the diverse glycosylation patterns of exosomes of different origins. They also facilitated comprehensive investigations on the cellular uptake of exosomes to disclose macropinocytosis as the main and general uptake route, while other endocytosis pathways are also partially involved in specific exosomes. Additionally, the new exosome functionalization approach has been demonstrated to be widely applicable to exosomes of different origins.

Surface Components and Biological Interactions of Extracellular Vesicles

Extracellular vesicles (EVs) are critical mediators of intercellular communication, carrying bioactive cargo and displaying diverse surface components that reflect their cellular origins and functions. The EV surface, composed of proteins, lipids, and glycocalyx elements, plays a pivotal role in targeting recipient cells, mediating biological interactions, and enabling selective cargo delivery. This review comprehensively examined the molecular architecture of EV surfaces, linking their biogenesis to functional diversity, and highlights their therapeutic and diagnostic potential in diseases such as cancer and cardiovascular disorders. Additionally, we explore emerging applications of EVs, including machine-learning-assisted analysis, chemical integration, and cross-system combinations. The review also discusses some key challenges in the clinical translation of EV-related technologies.

Recent Progress in Developing Extracellular Vesicles as Nanovehicles to Deliver Carbohydrate-Based Therapeutics and Vaccines

Cell-derived, nanoscale extracellular vesicles (EVs) have emerged as promising tools in diagnostic, therapeutic, and vaccine applications. Their unique properties including the capability to encapsulate diverse molecular cargo as well as the versatility in surface functionalization make them ideal candidates for safe and effective vehicles to deliver a range of biomolecules including gene editing cassettes, therapeutic proteins, glycans, and glycoconjugate vaccines. In this review, we discuss recent advances in the development of EVs derived from mammalian and bacterial cells for use in a delivery of carbohydrate-based protein therapeutics and vaccines. We highlight key innovations in EVs' molecular design, characterization, and deployment for treating diseases including Alzheimer's disease, infectious diseases, and cancers. We discuss challenges for their clinical translation and provide perspectives for future development of EVs within biopharmaceutical research and the clinical translation landscape.

Glycosylation on extracellular vesicles and its detection strategy: Paving the way for clinical use

Extracellular vesicles (EVs) contain various glycans during their life cycle, from biogenesis to cellular recognition and uptake by recipient cells. EV glycosylation has substantial diagnostic significance in multiple health conditions, highlighting the necessity of determining an accurate glycosylation pattern for EVs from diverse biological fluids. Reliable and accessible glycan detection techniques help to elaborate the glycosylation-related functional alterations of specific proteins or lipids. However, multiple obstacles exist, including the inconsistency in glycosylation patterns between an entire batch of EVs and a specific EV protein, and difficulty in distinguishing glycosylation types after tedious separation and purification procedures. This review outlines recent advances in EV glycan detection, either at the glycomic level for a collection of intact EVs or at the molecular level for a specific protein on EVs. Particular emphasis has been placed on the abundance of EVs in body fluids and their unique characteristics for drug delivery of EVs, indicating an opportunity for diagnostic and therapeutic purposes via EV glycans.

Extracellular vesicle-mediated crosstalk in tumor microenvironment dominates tumor fate

The tumor microenvironment (TME) is a complex and heterogeneous system containing various cells cooperating and competing with each other. Extracellular vesicles (EVs) differing in form and content are important intercellular communication mediators in the TME. Previous studies have focused on the cargoes within EVs rather than on the donors from which they originate and the recipient cells that exert their effects. Therefore, we provide here a detailed overview of the important roles of EVs in shaping tumor fate, highlighting their various mechanisms of intercellular dialog within the TME. We evaluate recent advances and also raise unresolved challenges to provide new ideas for clinical treatment strategies using EVs.

Siglecs-mediated immune regulation in neurological disorders

The surfaces of various immune cells are rich in glycan chains, including the sialic-acid-binding immunoglobulin-like lectins (Siglecs) family. As an emerging glyco-immune checkpoint, Siglecs have the ability to bind and interact with various glycoproteins, thereby eliciting a series of downstream reactions to modulate the immune response. The impact of Siglecs has been extensively studied in tumor immunotherapy. However, research in neurological disorders and neurological diseases is very limited, and therapeutic options involving Siglecs need further exploration. Siglecs play a crucial role in the development, homeostasis, and repair processes of the nervous system, especially in degenerative diseases. This review summarizes studies on the immunomodulatory role mediated by Siglecs expressed on different immune cells in various neurological disorders, elucidates how dysregulated sialic acid contributes to several psychiatric disorders, and discusses the progress and limitations of research on the treatment of neurological disorders.

Glioma-Derived Exosomes and Their Application as Drug Nanoparticles

Glioblastoma Multiforme (GBM) is the most aggressive primary tumor of the Central Nervous System (CNS) with a low survival rate. The malignancy of GBM is sustained by a bidirectional crosstalk between tumor cells and the Tumor Microenvironment (TME). This mechanism of intercellular communication is mediated, at least in part, by the release of exosomes. Glioma-Derived Exosomes (GDEs) work, indeed, as potent signaling particles promoting the progression of brain tumors by inducing tumor proliferation, invasion, migration, angiogenesis and resistance to chemotherapy or radiation. Given their nanoscale size, exosomes can cross the blood-brain barrier (BBB), thus becoming not only a promising biomarker to predict diagnosis and prognosis but also a therapeutic target to treat GBM. In this review, we describe the structural and functional characteristics of exosomes and their involvement in GBM development, diagnosis, prognosis and treatment. In addition, we discuss how exosomes can be modified to be used as a therapeutic target/drug delivery system for clinical applications.

Towards Understanding the Role of the Glycosylation of Proteins Present in Extracellular Vesicles in Urinary Tract Diseases: Contributions to Cancer and Beyond

Extracellular vesicles (EVs) are a population of nanoscale particles surrounded by a phospholipid bilayer, enabling intercellular transfer of bioactive molecules. Once released from the parental cell, EVs can be found in most biological fluids in the human body and can be isolated from them. For this reason, EVs have significant diagnostic potential and can serve as an excellent source of circulating disease biomarkers. Protein glycosylation plays a key role in many biological processes, and aberrant glycosylation is a hallmark of various diseases. EVs have been shown to carry multiple glycoproteins, but little is known about the specific biological roles of these glycoproteins in the context of EVs. Moreover, specific changes in EV glycosylation have been described for several diseases, including cancers and metabolic, cardiovascular, neurological or kidney diseases. Urine is the richest source of EVs, providing almost unlimited (in terms of volume) opportunities for non-invasive EV isolation. Recent studies have also revealed a pathological link between urinary EV glycosylation and urological cancers, as well as other pathologies of the urinary tract. In this review, we discuss recent research advances in this field and the diagnostic/prognostic potential of urinary EV glycosylation. In addition, we summarize common methods for isolating EVs from urine and techniques used to study their glycosylation.

Engineering Approaches for Exosome Cargo Loading and Targeted Delivery: Biological versus Chemical Perspectives

Exosomes are nanoscale membrane bound vesicles secreted by almost all types of cells. Their unique attributes, such as minimal immunogenicity and compatibility with biological systems, make them novel carriers for drug delivery. These native exosomes harbor proteins, nucleic acids, small molecule compounds, and fluorogenic agents. Moreover, through a combination of chemical and bioengineering methodologies, exosomes are tailored to transport precise therapeutic payloads to designated cells or tissues. In this review, we summarize the strategies for exosome modification and drug loading modalities in engineered exosomes. In addition, we provide an overview of the advances in the use of engineered exosomes for targeted drug delivery. Lastly, we discuss the merits and limitations of chemically engineered versus bioengineered exosome-mediated target therapies. These insights offer additional options for refining engineered exosomes in pharmaceutical development and hold promise for expediting the successful translation of engineered exosomes from the bench to the bedside.

Extracellular vesicles (EVs)' journey in recipient cells: from recognition to cargo release

Extracellular vesicles (EVs) are nano-sized bilayer vesicles that are shed or secreted by virtually every cell type. A variety of biomolecules, including proteins, lipids, coding and non-coding RNAs, and mitochondrial DNA, can be selectively encapsulated into EVs and delivered to nearby and distant recipient cells, leading to alterations in the recipient cells, suggesting that EVs play an important role in intercellular communication. EVs play effective roles in physiology and pathology and could be used as diagnostic and therapeutic tools. At present, although the mechanisms of exosome biogenesis and secretion in donor cells are well understood, the molecular mechanism of EV recognition and uptake by recipient cells is still unclear. This review summarizes the current understanding of the molecular mechanisms of EVs' biological journey in recipient cells, from recognition to uptake and cargo release. Furthermore, we highlight how EVs escape endolysosomal degradation after uptake and thus release cargo, which is crucial for studies applying EVs as drug-targeted delivery vehicles. Knowledge of the cellular processes that govern EV uptake is important to shed light on the functions of EVs as well as on related clinical applications.

Surface Sialic Acid Detection of Small Extracellular Vesicles at the Single-Particle Level by Nano-Flow Cytometry

Glycans, particularly sialic acids (SAs), play crucial roles in diverse biological processes. Despite their significance, analyzing specific glycans, such as sialic acids, on individual small extracellular vesicles (sEVs) has remained challenging due to the limited glycan capacity and substantial heterogeneity of sEVs. To tackle this issue, we introduce a chemical modification method of surface SAs on sEVs named PALEV-nFCM, which involves periodate oxidation and aniline-catalyzed oxime ligation (PAL), in conjunction with single-particle analysis using a laboratory-built nano-flow cytometer (nFCM). The specificity of the PALEV labeling method was validated using SA-decorated liposomes, enzymatic removal of terminal SA residues, lectin preblocking, and cellular treatment with an endogenous sialyltransferase inhibitor. Comprehensive mapping of SA distributions was conducted for sEVs derived from different sources, including conditioned cell culture medium (CCCM) of various cell lines, human saliva, and human red blood cells (RBCs). Notably, treatment with the calcium ionophore substantially increases the population of SA-positive RBC sEVs and enhances the SA content on individual RBC sEVs as well. nFCM provides a sensitive and versatile platform for mapping SAs of individual sEVs, which could significantly contribute to resolving the heterogeneity of sEVs and advancing the understanding of their glycosignature.

Biohybrid Nanorobots Carrying Glycoengineered Extracellular Vesicles Promote Diabetic Wound Repair through Dual-Enhanced Cell and Tissue Penetration

Considerable progress has been made in the development of drug delivery systems for diabetic wounds. However, underlying drawbacks, such as low delivery efficiency and poor tissue permeability, have rarely been addressed. In this study, a multifunctional biohybrid nanorobot platform comprising an artificial unit and several biological components is constructed. The artificial unit is a magnetically driven nanorobot surface modified with antibacterial 2-hydroxypropyltrimethyl ammonium chloride chitosan, which enables the entire platform to move and has excellent tissue penetration capacity. The biological components are two-step engineered extracellular vesicles that are first loaded with mangiferin, a natural polyphenolic compound with antioxidant properties, and then glycoengineered on the surface to enhance cellular uptake efficiency. As expected, the platform is more easily absorbed by endothelial cells and fibroblasts and exhibits outstanding dermal penetration performance and antioxidant properties. Encouraging results are also observed in infected diabetic wound models, showing improved wound re-epithelialization, collagen deposition, angiogenesis, and accelerated wound healing. Collectively, a biohybrid nanorobot platform that possesses the functionalities of both artificial units and biological components serves as an efficient delivery system to promote diabetic wound repair through dual-enhanced cell and tissue penetration and multistep interventions.

Exosome: From biology to drug delivery

In recent years, different advancements have been observed in nanosized drug delivery systems. Factors such as stability, safety and targeting efficiency cause hindrances in the clinical translation of these synthetic nanocarriers. Therefore, researchers employed endogenous nanocarriers like exosomes as drug delivery vehicles that have an inherent ability to target more efficiently after appropriate functionalization and show higher biocompatibility and less immunogenicity and facilitate penetration through the biological barriers more quickly than the other available carriers. Exosomes are biologically derived lipid bilayer-enclosed nanosized extracellular vesicles (size ranges from 30 to 150 nm) secreted from both prokaryotic and eukaryotic cells and appears significantly in the extracellular space. These EVs (extracellular vesicles) can exist in different sources, including mammals, plants and microorganisms. Different advanced techniques have been introduced for the isolation of exosomes to overcome the existing barriers present with conventional methods. Extensive research on the application of exosomes in therapeutic delivery for treating various diseases related to central nervous system, bone, cancer, skin, etc. has been employed. Several studies are on different stages of clinical trials, and many exosomes patents have been registered.

Extracellular vesicles in glioblastoma: Biomarkers and therapeutic tools

Glioblastoma (GBM) is the most aggressive tumor among the gliomas and intracranial tumors and to date prognosis for GBM patients remains poor, with a median survival typically measured in months to a few years depending on various factors. Although standardized therapies are routinely employed, it is clear that these strategies are unable to cope with heterogeneity and invasiveness of GBM. Furthermore, diagnosis and monitoring of responses to therapies are directly dependent on tissue biopsies or magnetic resonance imaging (MRI) techniques. From this point of view, liquid biopsies are arising as key sources of a variety of biomarkers with the advantage of being easily accessible and monitorable. In this context, extracellular vesicles (EVs), physiologically shed into body fluids by virtually all cells, are gaining increasing interest both as natural carriers of biomarkers and as specific signatures even for GBM. What makes these vesicles particularly attractive is they are also emerging as therapeutical vehicles to treat GBM given their native ability to cross the blood-brain barrier (BBB). Here, we reviewed recent advances on the use of EVs as biomarker for liquid biopsy and nanocarriers for targeted delivery of anticancer drugs in glioblastoma.

Exosome-Based Macromolecular neurotherapeutic drug delivery approaches in overcoming the Blood-Brain barrier for treating brain disorders

Delivering drugs to the brain is a complex challenge in medical research, particularly for disorders like Alzheimer's and Parkinson's. The blood-brain barrier restricts the entry of many therapeutic molecules, hindering their effectiveness. Nanoparticles, a potential solution, face issues like toxicity and limited approvals. A new avenue explores the use of small extracellular vesicles (sEVs), i.e., exosomes, as natural carriers for drug delivery. sEVs, tiny structures below 150 nm, show promise due to their minimal immune response and ability to precisely deliver drugs. This review focuses on the potential of sEVs-based drug delivery systems for treating neurological disorders, brain cancers, and other brain-related issues. Notably, bioengineered sEVs-carrying therapeutic compounds exhibit promise in early studies. The unique features of sEVs, such as their small size and natural properties, position them as candidates to overcome challenges in drug delivery to the brain. Ongoing clinical trials and research into sEVs behavior within the body further highlight their potential for revolutionizing drug delivery and addressing complex brain conditions.

Impacts of tissue context on extracellular vesicles-mediated cancer-host cell communications

Tumor tissue is densely packed with cancer cells, non-cancerous cells, and ECM, forming functional structures. Cancer cells transfer extracellular vesicles (EVs) to modify surrounding normal cells into cancer-promoting cells, establishing a tumor-favorable environment together with other signaling molecules and structural components. Such tissue environments largely affect cancer cell properties, and so as EV-mediated cellular communications within tumor tissue. However, current research on EVs focuses on functional analysis of vesicles isolated from the liquid phase, including cell culture supernatants and blood draws, 2D-cultured cell assays, or systemic analyses on animal models for biodistribution. Therefore, we have a limited understanding of local EV transfer within tumor tissues. In this review, we discuss the need to study EVs in a physiological tissue context by summarizing the current findings on the impacts of tumor tissue environment on cancer EV properties and transfer and the techniques required for the analysis. Tumor tissue environment is likely to alter EV properties, pose physical barriers, interactions, and interstitial flows for the dynamics, and introduce varieties in the cell types taken up. Utilizing physiological experimental settings and spatial analyses, we need to tackle the remaining questions on physiological EV-mediated cancer-host cell interactions. Understanding cancer EV-mediated cellular communications in physiological tumor tissues will lead to developing interaction-targeting therapies and provide insight into EV-mediated non-cancerous cells and interspecies interactions.

Surface Glycans of Microvesicles Derived from Endothelial Cells, as Probed Using Plant Lectins

Glycans of MVs are proposed to be candidates for mediating targeting specificity or at least promoting it. In contrast to exosomes, glycomic studies of MVs are largely absent. We studied the glycoprofile of endothelial cell-derived MVs using 21 plant lectins, and the results show the dominance of oligolactosamines and their α2-6-sialylated forms as N-glycans and low levels of α2-3-sialylated glycans. The low levels of α2-3-sialosides could not be explained by the action of extracellular glycosidases. Additionally, the level of some Man-containing glycans was also decreased in MVs. Spatial masking as the causative relationship between these low level glycans (as glycosphingolipids) by integral proteins or proteoglycans (thus, their lack of interaction with lectins) seems unlikely. The results suggest that integral proteins do not pass randomly into MVs, but instead only some types, differing in terms of their specific glycosylation, are integrated into MVs.

Extracellular vesicles as a new frontier of diagnostic biomarkers in osteosarcoma diseases: a bibliometric and visualized study

The use of liquid biopsy in cancer research has grown exponentially, offering potential for early detection, treatment stratification, and monitoring residual disease and recurrence. Exosomes, released by cancer cells, contain tumor-derived materials and are stable in biofluids, making them valuable biomarkers for clinical evaluation. Bibliometric research on osteosarcoma (OS) and exosome-derived diagnostic biomarkers is scarce. Therefore, we aimed to conduct a bibliometric evaluation of studies on OS and exosome-derived biomarkers. Using the Web of Science Core Collection database, Microsoft Excel, the R "Bibliometrix" package, CiteSpace, and VOSviewer software, quantitative analyses of the country, author, annual publications, journals, institutions, and keywords of studies on exosome-derived biomarkers for OS from 1995 to 2023 were performed. High-quality records (average citation rate ≥ 10/year) were filtered. The corresponding authors were mainly from China, the USA, Australia, and Canada. The University of Kansas Medical Center, National Cancer Center, Japan, and University of Kansas were major institutions, with limited cooperation reported by the University of Kansas Medical Center. Keyword analysis revealed a shift from cancer progression to mesenchymal stem cells, exosome expression, biogenesis, and prognostic biomarkers. Qualitative analysis highlighted exosome cargo, including miRNAs, circRNAs, lncRNAs, and proteins, as potential diagnostic OS biomarkers. This research emphasizes the rapid enhancement of exosomes as a diagnostic frontier, offering guidance for the clinical application of exosome-based liquid biopsy in OS, contributing to the evolving landscape of cancer diagnosis.

Magnetic nanoagent assisted deciphering of heterogeneous glycans in extracellular vesicles of varied cellular origins

Extracellular vesicles bear a rich glycome that presents versatile functions in diverse biological processes. Leverage polydopamine modified magnetic particles to serve as nanosized agents for rapid and robust EV capture and manipulation, we here integrated the easy magnetic actuation with specific lectin-glycan binding and enzyme-mediated fluorescence amplification and thus proposed a facile approach to efficiently decipher a broad spectrum of glycans in EVs. Termed magnetic nanoagent assisted extracellular vesicle glycan deciphering (MAEG), the developed assay utilized a magnet as the assistant operation tool and realized fast (∼1 h) and sensitive (a limit of detection of ∼0.7 μg/mL vesicles) EV glycan analysis in a simple low-cost (around 2.27 Chinese Yuan for one test) manner without requirement of any sophisticated platforms. With robust performance for different sample species, the assay achieved to depict the comprehensive glycosylation landscapes for varied EVs derived from eight cell lines focusing on non-small-cell lung cancer. Systematic analyses clearly revealed the high heterogeneity in glycan features of EVs of varied cellular origins. Using an established difference network method, unique glycan features in different EVs were sifted out and further compiled to construct lectin-denoted patterns as dedicated glycosylation fingerprints, potentially expanding EV-based clinical applications.

Exosome engineering for efficient and targeted drug delivery: Current status and future perspective

Exosomes are membrane-bound vesicles that are released by most cells. They carry nucleic acids, cytokines, growth factors, proteins, lipids, and metabolites. They are responsible for inter- and intracellular communications and their role in drug delivery is well defined. Exosomes have great potential for therapeutic applications, but the clinical use is restricted because of limitations in standardized procedures for isolation, purification, and drug delivery. Bioengineering of exosomes could be one approach to achieve standardization and reproducible isolation for clinical use. Exosomes are important transporters for targeted drug delivery because of their small size, stable structure, non-immunogenicity, and non-toxic nature, as well as their ability to carry a wide variety of compounds. These features of exosomes can be enhanced further by bioengineering. In this review, possible exosome bioengineering approaches, their biomedical applications, and targeted drug delivery are discussed.

Lectins as potential tools for cancer biomarker discovery from extracellular vesicles

Extracellular vesicles (EVs) have considerable potential as diagnostic, prognostic, and therapeutic agents, in large part because molecular patterns on the EV surface betray the cell of origin and may also be used to "target" EVs to specific cells. Cancer is associated with alterations to cellular and EV glycosylation patterns, and the surface of EVs is enriched with glycan moieties. Glycoconjugates of EVs play versatile roles in cancer including modulating immune response, affecting tumor cell behavior and site of metastasis and as such, paving the way for the development of innovative diagnostic tools and novel therapies. Entities that recognize specific glycans, such as lectins, may thus be powerful tools to discover and detect novel cancer biomarkers. Indeed, the past decade has seen a constant increase in the number of published articles on lectin-based strategies for the detection of EV glycans. This review explores the roles of EV glycosylation in cancer and cancer-related applications. Furthermore, this review summarizes the potential of lectins and lectin-based methods for screening, targeting, separation, and possible identification of improved biomarkers from the surface of EVs.

Strategies for Engineering of Extracellular Vesicles

Extracellular vesicles (EVs) are membrane vesicles released by cells into the extracellular space. EVs mediate cell-to-cell communication through local and systemic transportation of biomolecules such as DNA, RNA, transcription factors, cytokines, chemokines, enzymes, lipids, and organelles within the human body. EVs gained a particular interest from cancer biology scientists because of their role in the modulation of the tumor microenvironment through delivering bioactive molecules. In this respect, EVs represent an attractive therapeutic target and a means for drug delivery. The advantages of EVs include their biocompatibility, small size, and low immunogenicity. However, there are several limitations that restrict the widespread use of EVs in therapy, namely, their low specificity and payload capacity. Thus, in order to enhance the therapeutic efficacy and delivery specificity, the surface and composition of extracellular vesicles should be modified accordingly. In this review, we describe various approaches to engineering EVs, and further discuss their advantages and disadvantages to promote the application of EVs in clinical practice.

Plasma levels of neurology-related proteins are associated with cognitive performance in an older population with overweight/obesity and metabolic syndrome

Cognitive impairment is present in a broad spectrum of medical conditions and in aging. Here, we aimed to identify plasma proteins related to cognitive function in a sample of older adults with overweight/obesity and metabolic syndrome. A total of 129 subjects (mean age 64.7 years; 36% females) were grouped according to low (l-GCF, N=65) or high (h-GCF, N=64) global cognitive function and matched according to education, sex, age, and body mass index. Cognitive performance was assessed using neuropsychological tests. Plasma levels of 92 neurology-related proteins were assessed using a proximity extension assay. An elastic net regression analysis was used to identify proteins more associated with cognitive performance. Additionally, the protein expression levels were compared between the two groups by means of a t-test with false discovery rate correction. Pearson correlations were used to assess associations between the protein levels and scores from the neurocognitive tests. Six proteins (alpha-2-MRAP, HAGH, Siglec-9, MDGA1, IL12, and EDA2R) were identified as potential contributors to cognitive performance, remaining significantly increased in l-GCF compared to h-GCF participants after correction for multiple testing. Negative correlations (r= -0.23 to -0.18, i.e., lower protein levels, higher cognitive function) were found between global cognitive function and Siglec-9, NMNAT1, HAGH, LXN, gal-8, alpha-2-MRAP, IL12, PDGF-R-alpha, NAAA, EDA2R, CLEC1B, and LAT. Mini-mental state examination z scores showed the strongest correlations with protein levels, specifically negative correlations with CLEC1b, LXN, LAT, PLXNB3, NMNAT1, gal-8, HAGH, NAAA, CTSS, EZR, KYNU, MANF (r=-0.38 to -0.26) and a positive correlation with ADAM23 (r= 0.26). In summary, we identified several plasma proteins that were significantly associated with cognitive performance in older adults with obesity and metabolic syndrome, although further research is needed to replicate the results in larger samples and to include a predictive perspective.

Glutamine metabolic microenvironment drives M2 macrophage polarization to mediate trastuzumab resistance in HER2-positive gastric cancer

BACKGROUND

Trastuzumab is a first-line targeted therapy for human epidermal growth factor receptor-2 (HER2)-positive gastric cancer. However, the inevitable occurrence of acquired trastuzumab resistance limits the drug benefit, and there is currently no effective reversal measure. Existing researches on the mechanism of trastuzumab resistance mainly focused on tumor cells themselves, while the understanding of the mechanisms of environment-mediated drug resistance is relatively lacking. This study aimed to further explore the mechanisms of trastuzumab resistance to identify strategies to promote survival in these patients.

METHODS

Trastuzumab-sensitive and trastuzumab-resistant HER2-positive tumor tissues and cells were collected for transcriptome sequencing. Bioinformatics were used to analyze cell subtypes, metabolic pathways, and molecular signaling pathways. Changes in microenvironmental indicators (such as macrophage, angiogenesis, and metabolism) were verified by immunofluorescence (IF) and immunohistochemical (IHC) analyses. Finally, a multi-scale agent-based model (ABM) was constructed. The effects of combination treatment were further validated in nude mice to verify these effects predicted by the ABM.

RESULTS

Based on transcriptome sequencing, molecular biology, and in vivo experiments, we found that the level of glutamine metabolism in trastuzumab-resistant HER2-positive cells was increased, and glutaminase 1 (GLS1) was significantly overexpressed. Meanwhile, tumor-derived GLS1 microvesicles drove M2 macrophage polarization. Furthermore, angiogenesis promoted trastuzumab resistance. IHC showed high glutamine metabolism, M2 macrophage polarization, and angiogenesis in trastuzumab-resistant HER2-positive tumor tissues from patients and nude mice. Mechanistically, the cell division cycle 42 (CDC42) promoted GLS1 expression in tumor cells by activating nuclear factor kappa-B (NF-κB) p65 and drove GLS1 microvesicle secretion through IQ motif-containing GTPase-activating protein 1 (IQGAP1). Based on the ABM and in vivo experiments, we confirmed that the combination of anti-glutamine metabolism, anti-angiogenesis, and pro-M1 polarization therapy had the best effect in reversing trastuzumab resistance in HER2-positive gastric cancer.

CONCLUSIONS

This study revealed that tumor cells secrete GLS1 microvesicles via CDC42 to promote glutamine metabolism, M2 macrophage polarization, and pro-angiogenic function of macrophages, leading to acquired trastuzumab resistance in HER2-positive gastric cancer. A combination of anti-glutamine metabolism, anti-angiogenesis, and pro-M1 polarization therapy may provide a new insight into reversing trastuzumab resistance.

Comparison of immunotherapy mediated by apoptotic bodies, microvesicles and exosomes: apoptotic bodies' unique anti-inflammatory potential

Immunotherapy, including immunostimulation and immunosuppression, has seen significant development in the last 10 years. Immunostimulation has been verified as effective in anti-cancer treatment, while immunosuppression is used in the treatment of autoimmune disease and inflammation. Currently, with the update of newly-invented simplified isolation methods and the findings of potent triggered immune responses, extracellular vesicle-based immunotherapy is very eye-catching. However, the research on three main types of extracellular vesicles, exosomes, microvesicles and apoptotic bodies, needs to be more balanced. These three subtypes share a certain level of similarity, and at the same time, they have their own properties caused by the different methods of biogensis. Herein, we summarized respectively the status of immunotherapy based on each kind of vesicle and discuss the possible involved mechanisms. In conclusion, we highlighted that the effect of the apoptotic body is clear and strong. Apoptotic bodies have an excellent potential in immunosuppressive and anti-inflammatory therapies .

Current and prospective strategies for advancing the targeted delivery of CRISPR/Cas system via extracellular vesicles

Extracellular vesicles (EVs) have emerged as a promising platform for gene delivery owing to their natural properties and phenomenal functions, being able to circumvent the significant challenges associated with toxicity, problematic biocompatibility, and immunogenicity of the standard approaches. These features are of particularly interest for targeted delivery of the emerging clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) systems. However, the current efficiency of EV-meditated transport of CRISPR/Cas components remains insufficient due to numerous exogenous and endogenous barriers. Here, we comprehensively reviewed the current status of EV-based CRISPR/Cas delivery systems. In particular, we explored various strategies and methodologies available to potentially improve the loading capacity, safety, stability, targeting, and tracking for EV-based CRISPR/Cas system delivery. Additionally, we hypothesise the future avenues for the development of EV-based delivery systems that could pave the way for novel clinically valuable gene delivery approaches, and may potentially bridge the gap between gene editing technologies and the laboratory/clinical application of gene therapies.

Abscopal Effect, Extracellular Vesicles and Their Immunotherapeutic Potential in Cancer Treatment

The communication between tumor cells and the microenvironment plays a fundamental role in the development, growth and further immune escape of the tumor. This communication is partially regulated by extracellular vesicles which can direct the behavior of surrounding cells. In recent years, it has been proposed that this feature could be applied as a potential treatment against cancer, since several studies have shown that tumors treated with radiotherapy can elicit a strong enough immune response to eliminate distant metastasis; this phenomenon is called the abscopal effect. The mechanism behind this effect may include the release of extracellular vesicles loaded with damage-associated molecular patterns and tumor-derived antigens which activates an antigen-specific immune response. This review will focus on the recent discoveries in cancer cell communications via extracellular vesicles and their implication in tumor development, as well as their potential use as an immunotherapeutic treatment against cancer.

Emerging role of extracellular vesicles in multiple sclerosis: From cellular surrogates to pathogenic mediators and beyond

Multiple Sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system (CNS) driven by a complex interplay of genetic and environmental factors. While the therapeutic arsenal has expanded significantly for management of relapsing forms of MS, treatment of individuals with progressive MS is suboptimal. This treatment inequality is in part due to an incomplete understanding of pathomechanisms at different stages of the disease-underscoring the critical need for new biomarkers. Extracellular vesicles (EVs) and their bioactive cargo have emerged as endogenous nanoparticles with great theranostic potential-as diagnostic and prognostic biomarkers and ultimately as therapeutic candidates for precision nanotherapeutics. The goals of this review are to: 1) summarize the current data investigating the role of EVs and their bioactive cargo in MS pathogenesis, 2) provide a high level overview of advances and challenges in EV isolation and characterization for translational studies, and 3) conclude with future perspectives on this evolving field.

Surface Glycan Profiling of Extracellular Vesicles by Lectin Microarray and Glycoengineering for Control of Cellular Interactions

BACKGROUND

Extracellular vesicles (EVs) are a group of cell-derived membrane vesicles that carry a variety of cargo such as protein, nucleic acids, and lipids, and are secreted by almost all cell types. Functionally, EVs play important roles in physiological and pathological processes such as immune responses and tumor growth through intercellular communication by transferring this molecular information between cells. Therefore, they have potential versatile clinical applications as disease biomarkers and drug delivery carriers.

PROBLEM

Notably, subpopulations of EVs exhibit distinct characteristics depending on their cell of origin, including the expression of surface glycans, which have been implicated in a variety of cellular processes such as field cancerization, cell recognition, and signal transduction. However, these are features have not been fully exploited because of the difficulty in analyzing these proteins.

APPROACH

In this paper, we summarize the advancements in glycoengineering and high-performance lectin microarray for high-throughput analysis of EV glycans to generate an index of heterogeneity to identify disease biomarkers, and describe how understanding the function of EVs in disease can enhance their potential application in the clinic.

Exosomes; multifaceted nanoplatform for targeting brain cancers

At the moment, anaplastic changes within the brain are challenging due to the complexity of neural tissue, leading to the inefficiency of therapeutic protocols. The existence of a cellular interface, namely the blood-brain barrier (BBB), restricts the entry of several macromolecules and therapeutic agents into the brain. To date, several nano-based platforms have been used in laboratory settings and in vivo conditions to overcome the barrier properties of BBB. Exosomes (Exos) are one-of-a-kind of extracellular vesicles with specific cargo to modulate cell bioactivities in a paracrine manner. Regarding unique physicochemical properties and easy access to various biofluids, Exos provide a favorable platform for drug delivery and therapeutic purposes. Emerging data have indicated that Exos enable brain penetration of selective cargos such as bioactive factors and chemotherapeutic compounds. Along with these statements, the application of smart delivery approaches can increase delivery efficiency and thus therapeutic outcomes. Here, we highlighted the recent advances in the application of Exos in the context of brain tumors.

Life stage-specific glycosylation of extracellular vesicles from Schistosoma mansoni schistosomula and adult worms drives differential interaction with C-type lectin receptors DC-SIGN and MGL

Schistosomes can survive in mammalian hosts for many years, and this is facilitated by released parasite products that modulate the host’s immune system. Many of these products are glycosylated and interact with host cells via C-type lectin receptors (CLRs). We previously reported on specific fucose-containing glycans present on extracellular vesicles (EVs) released by schistosomula, the early juvenile life stage of the schistosome, and the interaction of these EVs with the C-type lectin receptor Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Non-integrin (DC-SIGN or CD209). EVs are membrane vesicles with a size range between 30–1,000 nm that play a role in intercellular and interspecies communication. Here, we studied the glycosylation of EVs released by the adult schistosome worms. Mass spectrometric analysis showed that GalNAcβ1–4GlcNAc (LacDiNAc or LDN) containing N-glycans were the dominant glycan type present on adult worm EVs. Using glycan-specific antibodies, we confirmed that EVs from adult worms were predominantly associated with LDN, while schistosomula EVs displayed a highly fucosylated glycan profile. In contrast to schistosomula EV that bind to DC-SIGN, adult worm EVs are recognized by macrophage galactose-type lectin (MGL or CD301), and not by DC-SIGN, on CLR expressing cell lines. The different glycosylation profiles of adult worm- and schistosomula-derived EVs match with the characteristic glycan profiles of the corresponding life stages and support their distinct roles in schistosome life-stage specific interactions with the host.

The hidden potential of glycomarkers: Glycosylation studies in the service of cancer diagnosis and treatment

Changes in the glycosylation process appear early in carcinogenesis and evolve with the growth and spread of cancer. The correlation of the characteristic glycosylation signature with the tumor stage and the appropriate therapy choice is an important issue in translational medicine. Oncologists also pay attention to extracellular vesicles as reservoirs of new cancer glycomarkers that can be potent for cancer diagnosis/prognosis. In this review, we recall glycomarkers used in oncology and show their new glycoforms of improved clinical relevance. We summarize current knowledge on the biological functions of glycoepitopes in cancer-derived extracellular vesicles and their potential use in clinical practice. Is glycomics a future of cancer diagnosis? It may be, but in combination with other omics analyses than alone.

Exosomes based strategies for brain drug delivery

Exosome application has emerged as a promising nanotechnology discipline for various diseases therapeutics and diagnoses. Owing to the natural properties of efficient drug delivery, higher biocompatibility, facile traversing of physiological barriers, and subtle side effects, exosomes shorten their way to clinical translation. Exosomes are nanoscale membrane-bound vesicles primarily involved in intercellular communication and exhibit natural blood-brain barrier (BBB) traversing ability, which enables their application as drug delivery vehicles for brain diseases treatment. Herein, we highlight recent exosome-based drug delivery endeavors for neurodegenerative diseases and brain cancer therapy, summarize the obstacles and future directions in clinical translation.

Exosome engineering in cell therapy and drug delivery

Cell-derived exosomes have opened new horizons in modern therapy for advanced drug delivery and therapeutic applications, due to their key features such as low immunogenicity, high physicochemical stability, capacity to penetrate into tissues, and the innate capacity to communicate with other cells over long distances. Exosome-based liquid biopsy has been potentially used for the diagnosis and prognosis of a range of disorders. Exosomes deliver therapeutic agents, including immunological modulators, therapeutic drugs, and antisense oligonucleotides to certain targets, and can be used as vaccines, though their clinical application is still far from reality. Producing exosomes on a large-scale is restricted to their low circulation lifetime, weak targeting capacity, and inappropriate controls, which need to be refined before being implemented in practice. Several bioengineering methods have been used for refining therapeutic applications of exosomes and promoting their effectiveness, on the one hand, and addressing the existing challenges, on the other. In the short run, new diagnostic platforms and emerging therapeutic strategies will further develop exosome engineering and therapeutic potential. This requires a thorough analysis of exosome engineering approaches along with their merits and drawbacks, as outlined in this paper. The present study is a comprehensive review of novel techniques for exosome development in terms of circulation time in the body, targeting capacity, and higher drug loading/delivery efficacies.

Surface Engineering of HEK293 Cell-Derived Extracellular Vesicles for Improved Pharmacokinetic Profile and Targeted Delivery of IL-12 for the Treatment of Hepatocellular Carcinoma

Background

Extracellular vesicles (EVs) are considered a promising drug delivery platform. Naïve EVs face numerous issues that limit their applications, such as fast clearance, hepatic accumulations, and a lack of target-specific tropism. We aimed to explore a series of surface engineering approaches to: 1) reduce the non-specific adhesion of EVs, and 2) improve their enrichment in the target tissue. As a proof-of-concept, we investigated the therapeutic potentials of a multi-modal EVs system carrying a tumor-specific nanobody and the immuno-stimulant interleukin-12 (IL12) using in vivo models of hepatocellular carcinoma.

Methods

The major cell adhesion molecule on the HEK293-derived EVs, integrin β1 (ITGB1), was knocked out (KO) by CRISPR/Cas9-mediated gene editing, followed by deglycosylation to generate ITGB1-Deg EVs for the subsequent pharmacokinetic and biodistribution analyses. ITGB1-Deg EVs were further loaded with glypican-3 (GPC3)-specific nanobody (HN3) and mouse single-chain IL12 (mscIL12) to generate ITGB1-mscIL12+HN3+Deg EVs, for evaluation of tumor tropism and therapeutic potential in a mice model of hepatocellular carcinoma.

Results

Removal of ITGB1 led to the broad suppression of integrins on the EVs surface, resulting in a decrease in cellular uptake. Deglycosylation of ITGB1- EVs gave rise to inhibition of the EVs uptake by activated RAW264.7 cells. ITGB1 removal did not significantly alter the pharmacokinetic behaviors of HEK293-EVs, whereas the ITGB1-Deg EVs exhibited enhanced systemic exposure with reduced hepatic accumulation. Loading of HN3 conferred the ITGB1-Deg EVs with tumor-specific tropism for both subcutaneous and metastasized tumors in mice. The ITGB1-mscIL12+HN3+Deg EVs activated mouse splenocytes with high potency. Systemic administration of the EVs with the equivalent dose of 1.5µg/kg of exosomal IL12 achieved satisfactory tumor growth inhibition and good tolerability.

Conclusion

The combinatorial approach of EVs surface engineering conferred HEK293-EVs with reduced non-specific clearance and enhanced tumor targeting efficacy, which constituted an efficient delivery platform for critical cancer therapeutics like IL12.

Effects of glioblastoma-derived extracellular vesicles on the functions of immune cells

Glioblastoma is the most aggressive variant of glioma, the tumor of glial origin which accounts for 80% of brain tumors. Glioblastoma is characterized by astoundingly poor prognosis for patients; a combination of surgery, chemo- and radiotherapy used for clinical treatment of glioblastoma almost inevitably results in rapid relapse and development of more aggressive and therapy resistant tumor. Recently, it was demonstrated that extracellular vesicles produced by glioblastoma (GBM-EVs) during apoptotic cell death can bind to surrounding cells and change their phenotype to more aggressive. GBM-EVs participate also in establishment of immune suppressive microenvironment that protects glioblastoma from antigen-specific recognition and killing by T cells. In this review, we collected present data concerning characterization of GBM-EVs and study of their effects on different populations of the immune cells (T cells, macrophages, dendritic cells, myeloid-derived suppressor cells). We aimed at critical analysis of experimental evidence in order to conclude whether glioblastoma-derived extracellular vesicles are a major factor in immune evasion of this deadly tumor. We summarized data concerning potential use of GBM-EVs for non-invasive diagnostics of glioblastoma. Finally, the applicability of approaches aimed at blocking of GBM-EVs production or their fusion with target cells for treatment of glioblastoma was analyzed.

Multi-functional extracellular vesicles: Potentials in cancer immunotherapy

Cancer immunotherapy (CIT) has revolutionized cancer treatment. However, the application of CIT is limited by low response rates and significant individual differences owing to a deficit in 1) immune recognition and 2) immune effector function. Extracellular vesicles (EVs) are cell-derived lipid bilayer-enclosed vesicles that mediate intercellular communication. The specific structure and content of EVs allows for multi-functional modulation of tumor immunity. Given their high biocompatibility, homologous targeting, and permeability across biological barriers, EVs have been evaluated as ideal carriers for promoting the efficacy and specificity of CIT. Herein, we first discuss the role of EVs in regulating tumor immunity and focus on the advantages of using EVs as a therapeutic tool for cancer treatment from a clinical perspective. Further, we outline the current progress in the development of biohybrid EVs for CIT and multi-functional EV-based strategies for overcoming the deficits in tumor immunity. Finally, we discuss the challenges associated with EV-based CIT and future perspectives in the context of ongoing clinical trials involving EV-based therapies, thus offering valuable insights into the future of multi-functional EVs in CIT.

Classification of Extracellular Vesicles Based on Surface Glycan Structures by Spongy-like Separation Media

Extracellular vesicles (EVs) are lipid bilayer vesicles that enclose various biomolecules. EVs hold promise as sensitive biomarkers to detect and monitor various diseases. However, they have heterogeneous molecular compositions. The compositions of EVs from identical donor cells obtained using the same purification methods may differ, which is a significant obstacle for elucidating objective biological functions. Herein, the potential of a novel lectin-based affinity chromatography (LAC) method to classify EVs based on their glycan structures is demonstrated. The proposed method utilizes a spongy-like monolithic polymer (spongy monolith, SPM), which consists of poly(ethylene-co-glycidyl methacrylate) with continuous micropores and allows an efficient in situ protein reaction with epoxy groups. Two distinct lectins with different specificities, Sambucus sieboldiana agglutinin and concanavalin A, are effectively immobilized on SPM without impacting the binding activity. Moreover, high recovery rates of liposomal nanoparticles as a model of EVs are achieved due to the large flow-through pores (>10 μm) of SPM compared to a typical agarose gel. Finally, lectin-immobilized SPMs are employed to classify EVs based on the surface glycan structures and demonstrate different subpopulations by proteome profiling. This is the first approach to clarify the variation of protein contents in EVs by the difference of surface glycans via lectin immobilized media.

Cell-specific targeting of extracellular vesicles through engineering the glycocalyx

Extracellular vesicles (EVs) are promising carriers for the delivery of a variety of chemical and biological drugs. However, their efficacy is limited by the lack of cellular specificity. Available methods to improve the tissue specificity of EVs predominantly rely on surface display of proteins and peptides, largely overlooking the dense glycocalyx that constitutes the outermost layer of EVs. In the present study, we report a reconfigurable glycoengineering strategy that can endogenously display glycans of interest on EV surface. Briefly, EV producer cells are genetically engineered to co-express a glycosylation domain (GD) inserted into the large extracellular loop of CD63 (a well-studied EV scaffold protein) and fucosyltransferase VII (FUT7) or IX (FUT9), so that the engineered EVs display the glycan of interest. Through this strategy, we showcase surface display of two types of glycan ligands, sialyl Lewis X (sLeX) and Lewis X, on EVs and achieve high specificity towards activated endothelial cells and dendritic cells, respectively. Moreover, the endothelial cell-targeting properties of sLeX-EVs were combined with the intrinsic therapeutic effects of mesenchymal stem cells (MSCs), leading to enhanced attenuation of endothelial damage. In summary, this study presents a reconfigurable glycoengineering strategy to produce EVs with strong cellular specificity and highlights the glycocalyx as an exploitable trait for engineering EVs.

Caveolae-Mediated Extracellular Vesicle (CMEV) Signaling of Polyvalent Polysaccharide Vaccination: A Host-Pathogen Interface Hypothesis

We published a study showing that improvement in response to splenectomy associated defective, in regards to the antibody response to Pneumovax® 23 (23-valent polysaccharides, PPSV23), can be achieved by splenocyte reinfusion. This study triggered a debate on whether and how primary and secondary immune responses occur based on humoral antibody responses to the initial vaccination and revaccination. The anti-SARS-CoV-2 vaccine sheds new light on the interpretation of our previous data. Here, we offer an opinion on the administration of the polyvalent polysaccharide vaccine (PPSV23), which appears to be highly relevant to the primary vaccine against SARS-CoV-2 and its booster dose. Thus, we do not insist this is a secondary immune response but an antibody response, nonetheless, as measured through IgG titers after revaccination. However, we contend that we are not sure if these lower but present IgG levels against pneumococcal antigens are clinically protective or are equally common in all groups because of the phenomenon of "hyporesponsiveness" seen after repeated polysaccharide vaccine challenge. We review the literature and propose a new mechanism-caveolae memory extracellular vesicles (CMEVs)-by which polysaccharides mediate prolonged and sustained immune response post-vaccination. We further delineate and explain the data sets to suggest that the dual targets on both Cav-1 and SARS-CoV-2 spike proteins may block the viral entrance and neutralize viral load, which minimizes the immune reaction against viral attacks and inflammatory responses. Thus, while presenting our immunological opinion, we answer queries and responses made by readers to our original statements published in our previous work and propose a hypothesis for all vaccination strategies, i.e., caveolae-mediated extracellular vesicle-mediated vaccine memory.

Lectin-Based Study Reveals the Presence of Disease-Relevant Glycoepitopes in Bladder Cancer Cells and Ectosomes

Bladder cancer is a malignancy that remains a therapeutic challenge and requires the identification of new biomarkers and mechanisms of progression. Several studies showed that extracellular vesicles promote angiogenesis, migration and metastasis, and inhibit apoptosis in bladder cancer. This effect may depend on their glycosylation status. Thus, the aim of this study was to compare glycosylation profiles of T-24 urothelial bladder cancer cells, HCV-29 normal ureter epithelial cells, and ectosomes released by both cell lines using lectin blotting and flow cytometry. Ectosomes displayed distinct total and surface glycosylation profiles with abundance of β-1,6-branched glycans and sialilated structures. Then, it was investigated whether the glycosylation status of the T-24 and HCV-29 cells is responsible for the effect exerted by ectosomes on the proliferation and migration of recipient cells. Stronger proproliferative and promigratory activity of T-24-derived ectosomes was observed in comparison to ectosomes from HCV-29 cells. When ectosomes were isolated from DMJ-treated cells, the aforementioned effects were diminished, suggesting that glycans carried by ectosomes were involved in modulation of recipient cell function. HCV-29- and T-24-derived ectosomes also increased the viability and motility of endothelial HUVEC cells and Hs27 fibroblasts. This supports the hypothesis that ectosomes can modulate the function of various cells present in the tumor microenvironment.

Phospholipid-Membrane-Based Nanovesicles Acting as Vaccines for Tumor Immunotherapy: Classification, Mechanisms and Applications

Membrane vesicles, a group of nano- or microsized vesicles, can be internalized or interact with the recipient cells, depending on their parental cells, size, structure and content. Membrane vesicles fuse with the target cell membrane, or they bind to the receptors on the cell surface, to transfer special effects. Based on versatile features, they can modulate the functions of immune cells and therefore influence immune responses. In the field of tumor therapeutic applications, phospholipid-membrane-based nanovesicles attract increased interest. Academic institutions and industrial companies are putting in effort to design, modify and apply membrane vesicles as potential tumor vaccines contributing to tumor immunotherapy. This review focuses on the currently most-used types of membrane vesicles (including liposomes, bacterial membrane vesicles, tumor- and dendritic-cell-derived extracellular vesicles) acting as tumor vaccines, and describes the classification, mechanism and application of these nanovesicles.

The cancer cell-derived extracellular vesicle glycocode in immunoevasion

Recent evidence suggests that cancer cell-derived extracellular vesicles might facilitate immunoevasion. Glycans are known to play a key role in immunomodulation, especially when tethered to biological membranes. However, the extracellular vesicle glycocode in cancer immunoevasion remains a largely unexplored area with promising potential for new putative diagnostic and therapeutic applications.

Glycan-Lectin Interactions as Novel Immunosuppression Drivers in Glioblastoma

Despite diagnostic and therapeutic improvements, glioblastoma (GB) remains one of the most threatening brain tumor in adults, underlining the urgent need of new therapeutic targets. Lectins are glycan-binding proteins that regulate several biological processes through the recognition of specific sugar motifs. Lectins and their ligands are found on immune cells, endothelial cells and, also, tumor cells, pointing out a strong correlation among immunity, tumor microenvironment and vascularization. In GB, altered glycans and lectins contribute to tumor progression and immune evasion, shaping the tumor-immune landscape promoting immunosuppressive cell subsets, such as myeloid-derived suppressor cells (MDSCs) and M2-macrophages, and affecting immunoeffector populations, such as CD8⁺ T cells and dendritic cells (DCs). Here, we discuss the latest knowledge on the immune cells, immune related lectin receptors (C-type lectins, Siglecs, galectins) and changes in glycosylation that are involved in immunosuppressive mechanisms in GB, highlighting their interest as possible novel therapeutical targets.

Extracellular vesicle glucose transporter-1 and glycan features in monocyte-endothelial inflammatory interactions

Monocyte-induced endothelial cell inflammation is associated with multiple pathological conditions, and extracellular vesicles (EVs) are essential nanosized components of intercellular communication. EVs derived from endotoxin-stimulated monocytes were previously shown to carry pro-inflammatory proteins and RNAs. The role of glucose transporter-1 (GLUT-1) and glycan features in monocyte-derived EV-induced endothelial cell inflammation remains largely unexplored. This study demonstrates that EVs derived from endotoxin-stimulated monocytes activate inflammatory pathways in endothelial cells, which are partially attributed to GLUT-1. Alterations in glycan features and increased levels of GLUT-1 were observed in EVs derived from endotoxin-stimulated monocytes. Notably, inhibition of EV-associated GLUT-1, through the use of fasentin, suppressed EV-induced inflammatory cytokines in recipient endothelial cells.