Quantitative Biodistribution and Pharmacokinetics Study of GMP-Grade Exosomes Labeled with 89Zr Radioisotope in Mice and Rats

Exploring the clinical transition of engineered exosomes designed for intracellular delivery of therapeutic proteins

Extracellular vesicles, particularly exosomes, have emerged as promising drug delivery systems owing to their unique advantages, such as biocompatibility, immune tolerability, and target specificity. Various engineering strategies have been implemented to harness these innate qualities, with a focus on enhancing the pharmacokinetic and pharmacodynamic properties of exosomes via payload loading and surface engineering for active targeting. This concise review outlines the challenges in the development of exosomes as drug carriers and offers insights into strategies for their effective clinical translation. We also highlight preclinical studies that have successfully employed anti-inflammatory exosomes and suggest future directions for exosome therapeutics. These advancements underscore the potential for integrating exosome-based therapies into clinical practice, heralding promise for future medical interventions.

The application of plant-exosome-like nanovesicles as improved drug delivery systems for cancer vaccines

The use of cancer immunotherapeutics is currently increasing. Cancer vaccines, as a form of immunotherapy, are gaining much attention in the medical community since specific tumor-antigens can activate immune cells to induce an anti-tumor immune response. However, the delivery of cancer vaccines presents many issues for research scientists when designing cancer treatments and requires further investigation. Nanoparticles, synthetic liposomes, bacterial vectors, viral particles, and mammalian exosomes have delivered cancer vaccines. In contrast, the use of many of these nanotechnologies produces many issues of cytotoxicity, immunogenicity, and rapid clearance by the mononuclear phagocyte system (MPS). Plant-exosome-like nanovesicles (PELNVs) can provide solutions for many of these challenges because they are innocuous and nonimmunogenic when delivering nanomedicines. Hence, this review will describe the potential use of PELNVs to deliver cancer vaccines. In this review, different approaches of cancer vaccine delivery will be detailed, the mechanism of oral vaccination for delivering cancer vaccines will be described, and the review will discuss the use of PELNVs as improved drug delivery systems for cancer vaccines via oral administration while also addressing the subsequent challenges for advancing their usage into the clinical setting.

Intranasal Administration of Mesenchymal Stem Cell-Derived Exosome Alleviates Hypoxic-Ischemic Brain Injury

Hypoxic-ischemic brain injury arises from inadequate oxygen delivery to the brain, commonly occurring following cardiac arrest, which lacks effective treatments. Recent studies have demonstrated the therapeutic potential of exosomes released from mesenchymal stem cells. Given the challenge of systemic dilution associated with intravenous administration, intranasal delivery has emerged as a promising approach. In this study, we investigate the effects of intranasally administered exosomes in an animal model. Exosomes were isolated from the cell supernatants using the ultracentrifugation method. Brain injury was induced in Sprague-Dawley rats through a transient four-vessel occlusion model. Intranasal administration was conducted with 3 × 108 exosome particles in 20 µL of PBS or PBS alone, administered daily for 7 days post-injury. Long-term cognitive behavioral assessments, biodistribution of exosomes, and histological evaluations of apoptosis and neuroinflammation were conducted. Exosomes were primarily detected in the olfactory bulb one hour after intranasal administration, subsequently distributing to the striatum and midbrain. Rats treated with exosomes exhibited substantial improvement in cognitive function up to 28 days after the insult, and demonstrated significantly fewer apoptotic cells along with higher neuronal cell survival in the hippocampus. Exosomes were found to be taken up by microglia, leading to a decrease in the expression of cytotoxic inflammatory markers.

Strategies for labelling of exogenous and endogenous extracellular vesicles and their application for in vitro and in vivo functional studies

This review presents a comprehensive overview of labelling strategies for endogenous and exogenous extracellular vesicles, that can be utilised both in vitro and in vivo. It covers a broad spectrum of approaches, including fluorescent and bioluminescent labelling, and provides an analysis of their applications, strengths, and limitations. Furthermore, this article presents techniques that use radioactive tracers and contrast agents with the ability to track EVs both spatially and temporally. Emphasis is also placed on endogenous labelling mechanisms, represented by Cre-lox and CRISPR-Cas systems, which are powerful and flexible tools for real-time EV monitoring or tracking their fate in target cells. By summarizing the latest developments across these diverse labelling techniques, this review provides researchers with a reference to select the most appropriate labelling method for their EV based research.

MSC-Derived Extracellular Vesicles Alleviate NLRP3/GSDMD-Mediated Neuroinflammation in Mouse Model of Sporadic Alzheimer's Disease

Alzheimer's disease (AD) is the most common neurodegenerative disease, with sporadic form being the predominant type. Neuroinflammation plays a critical role in accelerating pathogenic processes in AD. Mesenchymal stem cell (MSC)-derived small extracellular vesicles (MSC-sEVs) regulate inflammatory responses and show great promise for treating AD. Induced pluripotent stem cell (iPSC)-derived MSCs are similar to MSCs and exhibit low immunogenicity and heterogeneity, making them promising cell sources for clinical applications. This study examined the anti-inflammatory effects of MSC-sEVs in a streptozotocin-induced sporadic mouse model of AD (sAD). The intracisternal administration of iPSC-MSC-sEVs alleviated NLRP3/GSDMD-mediated neuroinflammation, decreased amyloid deposition and neuronal apoptosis, and mitigated cognitive dysfunction. Furthermore, it explored the role of miR-223-3p in the iPSC-MSC-sEVs-mediated anti-inflammatory effects in vitro. miR-223-3p directly targeted NLRP3, whereas inhibiting miR-223-3p almost completely reversed the suppression of NLRP3 by MSC-sEVs, suggesting that miR-223-3p may, at least partially, account for MSC-sEVs-mediated anti-inflammation. Results obtained suggest that intracisternal administration of iPSC-MSC-sEVs can reduce cognitive impairment by inhibiting NLRP3/GSDMD neuroinflammation in a sAD mouse model. Therefore, the present study provides a proof-of-principle for applying iPSC-MSC-sEVs to target neuroinflammation in sAD.

An ex vivo model of interactions between extracellular vesicles and peripheral mononuclear blood cells in whole blood

Extracellular vesicles (EVs) can be loaded with therapeutic cargo and engineered for retention by specific body sites; therefore, they have great potential for targeted delivery of biomolecules to treat diseases. However, the pharmacokinetics and biodistribution of EVs in large animals remain relatively unknown, especially in primates. We recently reported that when cell culture-derived EVs are administered intravenously to Macaca nemestrina (pig-tailed macaques), they differentially associate with specific subsets of peripheral blood mononuclear cells (PBMCs). More than 60% of CD20+ B cells were observed to associate with EVs for up to 1 h post-intravenous administration. To investigate these associations further, we developed an ex vivo model of whole blood collected from healthy pig-tailed macaques. Using this ex vivo system, we found that labelled EVs preferentially associate with B cells in whole blood at levels similar to those detected in vivo. This study demonstrates that ex vivo blood can be used to study EV-blood cell interactions.

Advancements in engineered exosomes for wound repair: current research and future perspectives

Wound healing is a complex and prolonged process that remains a significant challenge in clinical practice. Exosomes, a type of nanoscale extracellular vesicles naturally secreted by cells, are endowed with numerous advantageous attributes, including superior biocompatibility, minimal toxicity, and non-specific immunogenicity. These properties render them an exceptionally promising candidate for bioengineering applications. Recent advances have illustrated the potential of exosome therapy in promoting tissue repair. To further augment their therapeutic efficacy, the concept of engineered exosomes has been proposed. These are designed and functionally modifiable exosomes that have been tailored on the attributes of natural exosomes. This comprehensive review delineates various strategies for exosome engineering, placing specific emphasis on studies exploring the application of engineered exosomes for precision therapy in wound healing. Furthermore, this review sheds light on strategies for integrating exosomes with biomaterials to enhance delivery effectiveness. The insights presented herein provide novel perspectives and lay a robust foundation for forthcoming research in the realm of cutaneous wound repair therapies.

Challenges and future scope of exosomes in the treatment of cardiovascular diseases

Exosomes are nanosized vesicles that carry biologically diverse molecules for intercellular communication. Researchers have been trying to engineer exosomes for therapeutic purposes by using different approaches to deliver biologically active molecules to the various target cells efficiently. Recent technological advances may allow the biodistribution and pharmacokinetics of exosomes to be modified to meet scientific needs with respect to specific diseases. However, it is essential to determine an exosome's optimal dosage and potential side effects before its clinical use. Significant breakthroughs have been made in recent decades concerning exosome labelling and imaging techniques. These tools provide in situ monitoring of exosome biodistribution and pharmacokinetics and pinpoint targetability. However, because exosomes are nanometres in size and vary significantly in contents, a deeper understanding is required to ensure accurate monitoring before they can be applied in clinical settings. Different research groups have established different approaches to elucidate the roles of exosomes and visualize their spatial properties. This review covers current and emerging strategies for in vivo and in vitro exosome imaging and tracking for potential studies.

A Review of Labeling Approaches Used in Small Extracellular Vesicles Tracing and Imaging

Small extracellular vesicles (sEVs), a subset of extracellular vesicles (EVs) originating from the endosomal compartment, are a kind of lipid bilayer vesicles released by almost all types of cells, serving as natural carriers of nucleic acids, proteins, and lipids for intercellular communication and transfer of bioactive molecules. The current findings suggest their vital role in physiological and pathological processes. Various sEVs labeling techniques have been developed for the more advanced study of the function, mode of action, bio-distribution, and related information of sEVs. In this review, we summarize the existing and emerging sEVs labeling techniques, including fluorescent labeling, radioisotope labeling, nanoparticle labeling, chemical contrast agents labeling, and label-free technique. These approaches will pave the way for an in-depth study of sEVs. We present a systematic and comprehensive review of the principles, advantages, disadvantages, and applications of these techniques, to help promote applications of these labeling approaches in future research on sEVs.

Extracellular Vesicles and Intercellular Communication: Challenges for In Vivo Molecular Imaging and Tracking

Extracellular vesicles (EVs) are a heterogeneous class of cell-derived membrane vesicles released by various cell types that serve as mediators of intercellular signaling. When released into circulation, EVs may convey their cargo and serve as intermediaries for intracellular communication, reaching nearby cells and possibly also distant organs. In cardiovascular biology, EVs released by activated or apoptotic endothelial cells (EC-EVs) disseminate biological information at short and long distances, contributing to the development and progression of cardiovascular disease and related disorders. The significance of EC-EVs as mediators of cell-cell communication has advanced, but a thorough knowledge of the role that intercommunication plays in healthy and vascular disease is still lacking. Most data on EVs derive from in vitro studies, but there are still little reliable data available on biodistribution and specific homing EVs in vivo tissues. Molecular imaging techniques for EVs are crucial to monitoring in vivo biodistribution and the homing of EVs and their communication networks both in basal and pathological circumstances. This narrative review provides an overview of EC-EVs, trying to highlight their role as messengers of cell-cell interaction in vascular homeostasis and disease, and describes emerging applications of various imaging modalities for EVs visualization in vivo.

Purposing plant-derived exosomes-like nanovesicles for drug delivery: patents and literature review

INTRODUCTION

How can biotechnology and organic agriculture be fused and promoted simultaneously to overcome the main challenges in drug delivery systems, improving the quality of the care provided, [1] patient outcomes, and [2] reducing the side effects of most of the current treatments? Unfortunately, the role of organic agriculture in future human health treatment still represents a binary organic-conventional question, a debate perpetuating an either/or mentality. However, extracellular exosomes-like nanoparticles define a new organic path that plants and vegetables can release. In this review, we concisely propose plant-derived exosome-like nanovesicles and discuss their most important biological and pharmacological roles, representing a new tool for drug delivery.

AREAS COVERED

plant-derived exosomes-like nanovesicles; nature farming; green manufacturing practice; drug delivery; organic agriculture.

EXPERT OPINION

There is growing interest in the potential use of plant-derived exosomes-like nanovesicles for various diagnostic and therapeutic applications that should translate into a supplement to current nano-pharmaceuticals. Despite their clinical potential, the lack of sensitive preparatory and analytical technologies for plant-derived exosomes-like nanovesicles poses a barrier to clinical translation. An increasing number of articles are recently published on new analytical platforms to address these challenges in cross-comparison with conventional assay methods. This review also mentions two patents from ExoLab-Italia on plant-derived exosome-like nanovesicles, respectively, on plant-derived exosome-like nanovesicles' ability to naturally deliver a series of potentially therapeutic molecules and a novel approach to upload them with therapeutic molecules.

Exosome-Based Delivery of Super-Repressor IκBα Alleviates Alcohol-Associated Liver Injury in Mice

Activation of Kupffer cells (KCs) by gut-derived lipopolysaccharide (LPS) instigates nuclear factor-κB (NF-κB)-mediated inflammatory responses in alcohol-associated liver diseases (ALD). Here, we utilized a novel optogenetically engineered exosome technology called 'exosomes for protein loading via optically reversible protein-protein interactions (EXPLOR)' to efficiently deliver the super-repressor IκB-loaded exosomes (Exo-srIκB) to the liver and examined its therapeutic potential in acute-on-chronic alcohol-associated liver injury. We detected enhanced uptake of DiI-labeled Exo-srIκB by LPS-treated inflammatory KCs, which suppressed LPS-induced inflammatory gene expression levels. In animal experiments, a single intravenous injection of Exo-srIκB prior to alcohol binge drinking significantly attenuated alcohol-associated hepatic steatosis and infiltration of neutrophils and macrophages but not a liver injury. Notably, three consecutive days of Exo-srIκB injection remarkably reduced alcohol-associated liver injury, steatosis, apoptosis of hepatocytes, fibrosis-related gene expression levels in hepatic stellate cells, infiltration of neutrophils and macrophages, and inflammatory gene expression levels in hepatocytes and KCs. In particular, the above effects occurred with inhibition of nuclear translocation of NF-κB in liver tissues, and these beneficial effects of Exo-srIκB on ALD were shown regardless of doses. Our results suggest an exosome-based modulation of NF-κB activity in KCs by Exo-srIκB as a novel and efficient therapeutic approach in ALD.

Therapeutic potential of exosome-based personalized delivery platform in chronic inflammatory diseases

In the inflammatory microenvironment, there are numerous exosomes secreted by immune cells (Macrophages, neutrophils, dendritic cells), mesenchymal stem cells (MSCs) and platelets as intercellular communicators, which participate in the regulation of inflammation by modulating gene expression and releasing anti-inflammatory factors. Due to their good biocompatibility, accurate targeting, low toxicity and immunogenicity, these exosomes are able to selectively deliver therapeutic drugs to the site of inflammation through interactions between their surface-antibody or modified ligand with cell surface receptors. Therefore, the role of exosome-based biomimetic delivery strategies in inflammatory diseases has attracted increasing attention. Here we review current knowledge and techniques for exosome identification, isolation, modification and drug loading. More importantly, we highlight progress in using exosomes to treat chronic inflammatory diseases such as rheumatoid arthritis (RA), osteoarthritis (OA), atherosclerosis (AS), and inflammatory bowel disease (IBD). Finally, we also discuss their potential and challenges as anti-inflammatory drug carriers.

Biodistribution of 89Zr-DFO-labeled avian pathogenic Escherichia coli outer membrane vesicles by PET imaging in chickens

Avian pathogenic Escherichia coli (APEC) is a serious systemic infectious disease in poultry infections, causing severe economic losses to the poultry industry. Previous studies have shown that secretion of virulence proteins was required for the pathogenicity of APEC through the secretion system. Outer membrane vesicles (OMVs) are a generalized secretion system of Gram-negative bacteria that play a key role in the long-distance delivery of virulence factors, but whether they are associated with the pathogenic mechanism of APEC has not been determined. In this study, OMVs were purified and characterized from AE17 (O2 serotype) by ultracentrifugation and density gradient centrifugation and their protein cargo was identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In addition, ⁸⁹Zr was labeled after chelating AE17 OMVs by DFO and positron emission tomography PET imaging was used to track ⁸⁹Zr-DFO-OMVs in chickens and to pathologically analyze the distribution sites. This study showed that AE17 OMVs were membrane vesicles ranging in size from 20 to 200 nm and proteomic analysis revealed the presence of virulence proteins, including adhesion proteins OmpA, OmpC, OmpF, OmpX, FimH, FimC and FigE, and serum resistance proteins OmpT and MliC and immune response regulator proteins (FliC). In addition, in vivo PET imaging to track the biodistribution of AE17 OMVs showed that AE17 OMVs were taken up by the lung region and the gastrointestinal and renal regions but were not detected in other areas. Pathological analysis of the tissue sites where AE17 OMVs were ingested showed inflammatory responses and damage. These findings suggested that AE17 OMVs not only contained a group of virulence proteins associated with AE17 infection but can also deliver these virulence proteins over long distances and caused tissue inflammatory damage. Our study revealed a previously unidentified causative microbial signal in the pathogenesis of APEC that could aid in the development of vaccines and antibiotics effective against APEC.

Dual-labeled nanoparticles based on small extracellular vesicles for tumor detection

Background

Small extracellular vesicles (sEVs) are emerging natural nanoplatforms in cancer diagnosis and therapy, through the incorporation of signal components or drugs in their structure. However, for their translation into the clinical field, there is still a lack of tools that enable a deeper understanding of their in vivo pharmacokinetics or their interactions with the cells of the tumor microenvironment. In this study, we have designed a dual-sEV probe based on radioactive and fluorescent labeling of goat milk sEVs.

Results

The imaging nanoprobe was tested in vitro and in vivo in a model of glioblastoma. In vitro assessment of the uptake of the dual probe in different cell populations (RAW 264.7, U87, and HeLa) by optical and nuclear techniques (gamma counter, confocal imaging, and flow cytometry) revealed the highest uptake in inflammatory cells (RAW 264.7), followed by glioblastoma U87 cells. In vivo evaluation of the pharmacokinetic properties of nanoparticles confirmed a blood circulation time of ~ 8 h and primarily hepatobiliary elimination. The diagnostic capability of the dual nanoprobe was confirmed in vivo in a glioblastoma xenograft model, which showed intense in vivo uptake of the SEV-based probe in tumor tissue. Histological assessment by confocal imaging enabled quantification of tumor populations and confirmed uptake in tumor cells and tumor-associated macrophages, followed by cancer-associated fibroblasts and endothelial cells.

Conclusions

We have developed a chemical approach for dual radioactive and fluorescent labeling of sEVs. This methodology enables in vivo and in vitro study of these vesicles after exogenous administration. The dual nanoprobe would be a promising technology for cancer diagnosis and a powerful tool for studying the biological behavior of these nanosystems for use in drug delivery.

Graphical Abstract