Quantitative and functional characterisation of extracellular vesicles after passive loading with hydrophobic or cholesterol-tagged small molecules

Development of an innovative extracellular vesicle mimetic delivery platform for efficient miRNA delivery to tumours

Extracellular vesicles (EVs) display high degree of tissue tropism and therefore represent promising carriers for tissue-specific delivery of genes or drugs for the treatment of human diseases. However, current approaches for the loading of therapeutics into EVs have low entrapment efficiency and also do not adequately deplete endogenous EV content; thus, more effective approaches are needed. Here, we report an innovative EXtraCElluar vesicle surface Ligand-NanoParticles (EXCEL NPs), generated by transferring moieties of EVs onto the surface of synthetic nanoparticles. EXCEL NPs facilitate the efficient entrapment of therapeutics (89 % efficiency) and are completely devoid of pre-existing unwanted EV internal content. Importantly, we show that EXCEL NPs formulated using EVs derived from endothelial cells, astrocytes and macrophages retain the delivery characteristics of the original EVs. Using miRNA-146a as a model anti-cancer therapeutic, we further demonstrated successful delivery of miRNA-146a to IG10 orthotopic ovarian tumours in immune competent mice using EXCEL NPs formulated with macrophage-derived EVs. Our findings establish a new clinically translatable approach to leverage characteristics of endogenous EVs for therapeutic delivery. The versatility of the platform enables future application to different target cell types and therapeutic modalities.

Neutrophil-Derived Extracellular Vesicles for Facile Delivery of Diagnostic Agents to Tumor Microenvironments

Targeted delivery of diagnostic and therapeutic agents to tumor microenvironments using nanoparticles improves the efficacy of these agents and reduces their unwarranted side effects. Numerous synthetic nanoparticle systems have been designed for this very purpose, but few have translated clinically due to poor efficacy-to-cost and efficacy-to-toxicity ratios. Biological nanoparticles such as modified extracellular vesicles (EVs) that are likely to have lower toxicities have also been developed but face challenges in clinical translation as they have primarily been produced from cancerous cells/cell lines and have high batch-to-batch variability. To overcome these issues, herein, we demonstrate that EVs isolated from neutrophils may be loaded with a specific diagnostic agent (indocyanine green) in a facile manner within a few hours, that these agent-loaded EVs are retained in vivo in mouse tumors for longer with a ∼5-fold increase in retention when compared to free diagnostic agents and hence facilitate short-term longitudinal imaging of the tumor microenvironments. The use of an individual's own cell-derived EVs requiring minimal ex vivo manipulations increases the likelihood of translating such a system into the clinic.

Extracellular vesicles as cancer biomarkers and drug delivery strategies in clinical settings: Advances, perspectives, and challenges

Cancer is a leading cause of death worldwide, and despite the introduction of new therapeutic approaches for advanced cases aimed at improving patient survival, only a subset of patients benefits from a complete response. In this context, there is a growing need for new cancer biomarkers and therapeutic strategies, and the use of Extracellular Vesicles (EVs) has been widely explored in various approaches. As circulating lipid-bilayer particles carrying a variety of biological information from tumor cells, EVs can be employed as good biomarkers of diagnosis, prognosis, therapy evaluation, and as adjuvants in cancer treatment. In this review, we provide a brief overview of the different types of EVs and their biogenesis and discuss how tumor-derived EV cargo can serve as a potential biomarker in clinical settings through liquid biopsy. We also highlight recent advances in EV nanoengineering and their potential as adjuvants in cancer treatment. Finally, we discuss the key unknowns, gaps, and bottlenecks that must be addressed to fully integrate EVs into precision oncology.

Control of Physical and Biochemical Parameters Influencing Exogeneous Cargo Protein Association to Extracellular Vesicles Using Lipid Anchors Enables High Loading and Effective Intracellular Delivery

Despite biomolecule delivery is a natural function of extracellular vesicles (EVs), low loading of exogenous macromolecules such as proteins into EVs limits their interest as convincing protein delivery systems for health applications. In this context, lipid-anchorage of exogenous cargo into EV membrane recently emerged as a promising option to enable their vectorisation into cells. Nevertheless, this option was not explored for protein intracellular delivery, and further characterisation of critical parameters governing the association of a lipid-anchored cargo protein to EVs is still needed to confirm the relevance of this anchorage strategy. Therefore, we sought to identify these parameters in a precise and quantitative manner, using bulk and single nanoparticle analysis methods to identify protein loading capacity and subsequent intracellular delivery. We identified incubation temperature, cargo concentration, lipid anchor (LA) structure (lipid nature, linker) and EV origin as critical factors influencing maximal EV loading capacity. Precise control of these parameters enabled to load cargo protein close to EV saturation without hindering cellular delivery. The structural properties of LA influenced not only cargo protein/EV association but also intracellular delivery into different carcinoma cell lines. By thoroughly characterising Lipid-PEG-protein anchorage, this study evidences the interest of this tunable and controllable approach for efficient EV protein delivery.

A critical review of sensors for detecting per- and polyfluoroalkyl substances: Focusing on diverse molecular probes

Per and Polyfluoroalkyl Substances (PFASs) pose a severe threat to the ecological environment and human health due to their persistence, bioaccumulation, and potential toxicity in the environment. Currently, the detection methods of PFASs generally rely on the combination of chromatographic techniques and mass spectrometry, which are typically suitable for laboratory testing. To meet the requirements of on-site detection, there is an urgent need to develop convenient and efficient detection methods. Sensors, as the preferred alternative, have been widely studied. In order to deeply investigate the mechanism of sensors in recognizing PFASs, this review, from the unique perspective of molecular probes, summarizes the construction and recognition mechanisms of four molecular probes: antibodies, aptamers, synthesized micromolecules, and synthesized polymers for PFASs. This review focuses on PFOA and PFOS as representative perfluoroalkyl substances and systematically investigates their properties and effects. It also analyzes the respective advantages, disadvantages, and applicable scenarios, and discusses the future development trends.

Isolation and characterization of medicinal plant-based extracellular vesicles as nano delivery systems for ascorbic acid

AIM

Plant-derived extracellular vesicles (EVs) are natural nanovesicles for drug delivery. This study isolated and characterised EVs from medicinal plants as delivery vehicles.

METHODS

Precipitation method was employed for the isolation and characterised using DLS, SEM, and TEM. The encapsulation efficiency (EE) and antioxidant activity of ascorbic acid (AA)-EVs were evaluated.

RESULTS

The total yields of lyophilised vesicles per weight of the sample were 6.0, 8.6 and 9.2 mg/g for garlic, turmeric and ginger, respectively. Mean size of garlic-derived EVs, ginger-derived EVs, and turmeric-derived EVs were 101.0 ± 6.7, 226.4 ± 62.2 and 90.7 ± 2.5 nm, respectively. The zeta potential of the EVs was between -33.2 ± 10.9 and -28.8 ± 8.43 mV. Spherical morphology of the nanovesicles was confirmed by SEM and TEM. The EE of the EVs was between 78.1 ± 2.8% and 87.2 ± 1.4%.

CONCLUSION

Overall, the antioxidant activity of AA-loaded EVs was better compared to free AA. This study provides evidence that these medicinal plants are rich sources for developing nanotherapeutics.

Natural and Bioengineered Extracellular Vesicles in Diagnosis, Monitoring and Treatment of Cancer

Extracellular vesicles (EVs) are cell derived nanovesicles which are implicated in both physiological and pathological intercellular communication, including the initiation, progression, and metastasis of cancer. The exchange of biomolecules between stromal cells and cancer cells via EVs can provide a window to monitor cancer development in real time for better diagnostic and interventional strategies. In addition, the process of secretion and internalization of EVs by stromal and cancer cells in the tumor microenvironment (TME) can be exploited for delivering therapeutics. EVs have the potential to provide a targeted, biocompatible, and efficient delivery platform for the treatment of cancer and other diseases. Natural as well as engineered EVs as nanomedicine have immense potential for disease intervention. Here, we provide an overview of current knowledge of EVs' function in cancer progression, diagnostic and therapeutic applications for EVs in the cancer setting, as well as current EV engineering strategies.

Loading of Extracellular Vesicles with Nucleic Acids via Hybridization with Non-Lamellar Liquid Crystalline Lipid Nanoparticles

The translation of cell-derived extracellular vesicles (EVs) into biogenic gene delivery systems is limited by relatively inefficient loading strategies. In this work, the loading of various nucleic acids into small EVs via their spontaneous hybridization with preloaded non-lamellar liquid crystalline lipid nanoparticles (LCNPs), forming hybrid EVs (HEVs) is described. It is demonstrated that LCNPs undergo pH-dependent structural transitions from inverse hexagonal (HII) phases at pH 5 to more disordered non-lamellar phases, possibly inverse micellar (L2) or sponge (L3) phases, at pH 7.4, which are particularly suitable for inducing a controlled hybridization process with EVs. State-of-the-art single-particle analysis techniques reveal that LCNPs interact with various EV subpopulations at physiological conditions and that ≈40% of HEVs are loaded with the genetic cargo. Importantly, this study demonstrates that EV membrane proteins remain accessible on HEV surfaces, with their intrinsic enzymatic activity unaffected after the hybridization process. Finally, HEVs show in vitro improved transfection efficiencies compared to unhybridized LCNPs. In summary, this versatile platform holds potential for loading various nucleic acid molecules into native EVs and may help developing EV-based therapeutics.

Extracellular vesicle surface engineering with integrins (ITGAL & ITGB2) to specifically target ICAM-1-expressing endothelial cells

Extracellular vesicles (EVs) are taken up by most cells, however specific or preferential cell targeting remains a hurdle. This study aims to develop an EV that targets cells involved in inflammation, specifically those expressing intercellular adhesion molecule-1 (ICAM-1). To target these cells, we overexpress the ICAM-1 binding receptor "lymphocyte function-associated antigen-1" (LFA-1) in HEK293F cells, by sequential transfection of plasmids of the two LFA-1 subunits, ITGAL and ITGB2 (CD11a and CD18). The LFA-1 receptor was strongly overexpressed on the EVs released by the transfected cells. We further loaded these EVs with a therapeutic peptide, targeting myeloid differentiation primary response 88 (Myd88; EVMyd88), through a developed EV open-and-close procedure. Myd88 is a downstream common intracellular messenger for most TLR-receptors. EV expression of LFA-1 increases EV binding to ICAM-1-expressing cells, an effect that was dose-dependently inhibited by a specific neutralizing ICAM-1 antibody. Further, activated human endothelial cells treated with LFA-1 EVMyd88 had increased uptake of these EVs, resulting in dose-dependent inhibition of induced release of IL-8, presumably by targeting Myd88. We conclude that LFA-1-expressing EVMyd88 may be a candidate suitable for delivering therapeutic peptides in inflammatory diseases associated with TLR-activation.

Surface-Enhanced Raman Scattering (SERS)-based biosensors for advanced extracellular vesicle detection: A review

BACKGROUND

Extracellular Vesicles (EVs), as nano-scale vesicles rich in biological information, hold an indispensable status in the biomedical field. However, due to the intrinsic small size and low abundance of EVs, their effective detection presents significant challenges. Although various EV detection techniques exist, their sensitivity and ease of operation still need enhancement.

RESULTS

Surface-Enhanced Raman Scattering (SERS) is known for its high sensitivity and specificity. It stands out in tackling the challenges that traditional EV detection methods face. In this review, we focus on the application of SERS-based biosensors in EV detection. It provides a detailed introduction to the recognition and capture of EVs, strategies for mediating signal amplification, and detection of EV biomarkers. Finally, the challenges and prospects of SERS-based biosensors are discussed.

SIGNIFICANCE

SERS-based biosensor enhances the Raman signal, allowing for the detection of biomarkers at low concentrations. This capability reveals its substantial potential in identifying EVs and analyzing molecular data. It paves the path for advanced EV detection.

Magnetoelectric Extracellular Vesicle Latency-Targeting (MELT) Nanotherapeutic for the Block-Lock-and-Kill HIV Eradication Strategy

BACKGROUND

Human immunodeficiency virus (HIV) establishes latent infections in cellular reservoirs, including microglia. HC69 cells, a microglial model of HIV latency, contain an HIV promoter long terminal repeat (LTR)-GFP reporter and were used for testing the efficacy of a two-step magnetoelectric nanoparticle (MENP) and extracellular vesicle (xEV) latency-targeting (MELT) nanotherapeutic. GFP expression in HC69 at rest is low (GFPLo), and upon exposure to LTR, transcription-activating agents (i.e., TNF-α) are induced to be high expressing (GFPHi).

METHODS

The first step of MELT utilized ZL0580, an HIV Tat inhibitor loaded into EVs (80%) via incubation. ZL0580-EVs were taken up by GFPLo and blocked LTR transcriptional reactivation by 50% and were 90% less toxic than ZL0580 alone. The second step in MELT involved conjugation of monomethyl auristatin E (MMAE) to MENPs. HPLC measurements showed 80% MMAE attachment to MENPs. Flow cytometry-based measurements of the membrane potential indicated that the membranes of GFPHi HC69 were 60% more polarized than GFPLo HC69 cells. More MMAE-MENPs were internalized by GFPLo HC69.

RESULTS

Using a mixed-cell blood-brain barrier (BBB) Transwell model, we demonstrated that 20% of MELT crossed the BBB, was taken up by HC69 cells, and reduced LTR reactivation by 10%.

CONCLUSIONS

Overall, this study demonstrated that MELT can potentially be utilized as a nanotherapeutic to target HIV latency in microglia.

Extracellular vesicles versus lipid nanoparticles for the delivery of nucleic acids

Extracellular vesicles (EVs) are increasingly investigated for delivering nucleic acid (NA) therapeutics, leveraging their natural role in transporting NA and protein-based cargo in cell-to-cell signaling. Their synthetic counterparts, lipid nanoparticles (LNPs), have been developed over the past decades as NA carriers, culminating in the approval of several marketed formulations such as patisiran/Onpattro® and the mRNA-1273/BNT162 COVID-19 vaccines. The success of LNPs has sparked efforts to develop innovative technologies to target extrahepatic organs, and to deliver novel therapeutic modalities, such as tools for in vivo gene editing. Fueled by the recent advancements in both fields, this review aims to provide a comprehensive overview of the basic characteristics of EV and LNP-based NA delivery systems, from EV biogenesis to structural properties of LNPs. It addresses the primary challenges encountered in utilizing these nanocarriers from a drug formulation and delivery perspective. Additionally, biodistribution profiles, in vitro and in vivo transfection outcomes, as well as their status in clinical trials are compared. Overall, this review provides insights into promising research avenues and potential dead ends for EV and LNP-based NA delivery systems.

Basic Guide for Approaching Drug Delivery with Extracellular Vesicles

Extracellular vesicles (EVs) are natural carriers of biomolecules that play a crucial role in cell-to-cell communication and tissue homeostasis under normal and pathological conditions, including inflammatory diseases and cancer. Since the discovery of the pro-regenerative and immune-modulating properties of EVs, EV-based therapeutics have entered clinical trials for conditions such as myocardial infarction and autoimmune diseases, among others. Due to their unique advantages-such as superior bioavailability, substantial packaging capacity, and the ability to traverse biological barriers-EVs are regarded as a promising platform for targeted drug delivery. However, achieving a sufficient accumulation of therapeutic agents at the target site necessitates a larger quantity of EVs per dose compared to using EVs as standalone drugs. This challenge can be addressed by administering larger doses of EVs, increasing the drug dosage per administration, or enhancing the selective accumulation of EVs at target cells. In this review, we will discuss methods to improve the isolation and purification of EVs, approaches to enhance cargo packaging-including proteins, RNAs, and small-molecule drugs-and technologies for displaying targeting ligands on the surface of EVs to facilitate improved targeting. Ultimately, this guide can be applied to the development of novel classes of EV-based therapeutics and to overcoming existing technological challenges.

DNA Nanomaterial-Empowered Surface Engineering of Extracellular Vesicles

Extracellular vesicles (EVs) are cell-secreted biological nanoparticles that are critical mediators of intercellular communication. They contain diverse bioactive components, which are promising diagnostic biomarkers and therapeutic agents. Their nanosized membrane-bound structures and innate ability to transport functional cargo across major biological barriers make them promising candidates as drug delivery vehicles. However, the complex biology and heterogeneity of EVs pose significant challenges for their controlled and actionable applications in diagnostics and therapeutics. Recently, DNA molecules with high biocompatibility emerge as excellent functional blocks for surface engineering of EVs. The robust Watson-Crick base pairing of DNA molecules and the resulting programmable DNA nanomaterials provide the EV surface with precise structural customization and adjustable physical and chemical properties, creating unprecedented opportunities for EV biomedical applications. This review focuses on the recent advances in the utilization of programmable DNA to engineer EV surfaces. The biology, function, and biomedical applications of EVs are summarized and the state-of-the-art achievements in EV isolation, analysis, and delivery based on DNA nanomaterials are introduced. Finally, the challenges and new frontiers in EV engineering are discussed.

Development and Evaluation of Reconstructed Nanovesicles from Turmeric for Multifaceted Obesity Intervention

The escalating prevalence of obesity poses significant health challenges due to its direct association with various diseases. Most existing medications, such as appetite suppressants and fat absorption inhibitors, suffer from limited effectiveness and undesirable side effects. Here, inspired by the versatile metabolic effects of turmeric, we developed a naturally derived nanoformulation of "Reconstructed Turmeric-derived Nanovesicles (Rec-tNVs)" for obesity treatment. Employing quantitative nanoflow cytometry, a four-orders-of-magnitude increase in curcumin content (∼108 molecules per particle) was identified in individual Rec-tNVs compared to their ultracentrifugation-isolated counterparts. Rec-tNVs, featuring highly aggregated curcumin arrangements and other coencapsulated bioactive compounds, demonstrated a dose-dependent lipid-lowering effect in mature 3T3-L1 cells by promoting lipolysis, suppressing lipogenesis, inducing adipocyte browning, and triggering apoptosis after internalization via multiple pathways. In vivo experiments revealed that Rec-tNVs alleviated obesity more effectively than free curcumin and achieved weight reductions of 18.68 and 14.56% through intragastric and subcutaneous delivery, respectively, in high-fat-diet mouse models over a four-week treatment period. These effects were attributed to targeted actions on adipose tissues and systemic impacts on metabolism and gut microbiota composition. Overall, this study underscores the multifaceted antiobesity efficacy of Rec-tNVs, and offers a promising paradigm for developing plant-derived nanovesicle-based therapeutics.

Composition, functions, and applications of exosomal membrane proteins

Exosomes play a crucial role in various biological processes, such as human development, immune responses, and disease occurrence. The membrane proteins on exosomes are pivotal factors for their biological functionality. Currently, numerous membrane proteins have been identified on exosome membranes, participating in intercellular communication, mediating target cell recognition, and regulating immune processes. Furthermore, membrane proteins from exosomes derived from cancer cells can serve as relevant biomarkers for early cancer diagnosis. This article provides a comprehensive review of the composition of exosome membrane proteins and their diverse functions in the organism's biological processes. Through in-depth exploration of exosome membrane proteins, it is expected to offer essential foundations for the future development of novel biomedical diagnostics and therapies.

Defining tropism and activity of natural and engineered extracellular vesicles

Extracellular vesicles (EVs) have important roles as mediators of cell-to-cell communication, with physiological functions demonstrated in various in vivo models. Despite advances in our understanding of the biological function of EVs and their potential for use as therapeutics, there are limitations to the clinical approaches for which EVs would be effective. A primary determinant of the biodistribution of EVs is the profile of proteins and other factors on the surface of EVs that define the tropism of EVs in vivo. For example, proteins displayed on the surface of EVs can vary in composition by cell source of the EVs and the microenvironment into which EVs are delivered. In addition, interactions between EVs and recipient cells that determine uptake and endosomal escape in recipient cells affect overall systemic biodistribution. In this review, we discuss the contribution of the EV donor cell and the role of the microenvironment in determining EV tropism and thereby determining the uptake and biological activity of EVs.

Mesenchymal stem cell-derived extracellular vesicles for treatment of bone loss within periodontitis in pre-clinical animal models: a meta-analysis

BACKGROUND

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) represent an effective and promising strategy for periodontitis, although studies remain pre-clinical. Herein, a meta-analysis was conducted to assess the efficacy of MSC-EVs in animal models of periodontitis.

METHODS

The PubMed, Web of Science, and Embase electronic databases were searched up to Dec 2022 to retrieve preclinical studies examining the use of MSC-EVs for periodontitis treatment. Meta-analyses and sub-group analyses were performed to assess the effect of MSC-EVs on Bone Volume/Total Volume (BV/TV) or the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) in pre-clinical animal models of periodontitis.

RESULTS

11 studies published from Mar 2019 to Oct 2022 met the inclusion criteria. Overall, MSC-EVs contributed to periodontal bone regeneration in the inflammatory bone loss area due to periodontitis, as represented by a weighted mean difference (WMD) of 14.07% (95% CI = 6.73, 21.41%, p < 0.001) for BV/TV and a WMD of -0.12 mm (95% CI= -0.14, -0.11 mm, p < 0.001) for CEJ-ABC. However, sub-analysis suggested that there was no significant difference in CEJ-ABC between studies with bioactive scaffolds and studies without bioactive scaffolds (p = 0.60).

CONCLUSIONS

The present study suggests that MSC-EVs may represent an attractive therapy for the treatment of inflammatory bone loss within periodontitis.