Comparative analysis of tangential flow filtration and ultracentrifugation, both combined with subsequent size exclusion chromatography, for the isolation of small extracellular vesicles

High-yield extracellular vesicle production from HEK293T cells encapsulated in 3D auxetic scaffolds with cyclic mechanical stimulation for effective drug carrier systems

Extracellular vesicles (EVs) show promise in drug loading and delivery for medical applications. However, the lack of scalable manufacturing processes hinders the generation of clinically suitable quantities, thereby impeding the translation of EV-based therapies. Current EV production relies heavily on non-physiological two-dimensional (2D) cell culture or bioreactors, requiring significant resources. Additionally, EV-derived ribonucleic acid cargo in three-dimensional (3D) and 2D culture environments remains largely unknown. In this study, we optimized the biofabrication of 3D auxetic scaffolds encapsulated with human embryonic kidney 293 T (HEK293 T) cells, focusing on enhancing the mechanical properties of the scaffolds to significantly boost EV production through tensile stimulation in bioreactors. The proposed platform increased EV yields approximately 115-fold compared to conventional 2D culture, possessing properties that inhibit tumor progression. Further mechanistic examinations revealed that this effect was mediated by the mechanosensitivity of YAP/TAZ. EVs derived from tensile-stimulated HEK293 T cells on 3D auxetic scaffolds demonstrated superior capability for loading doxorubicin compared to their 2D counterparts for cancer therapy. Our results underscore the potential of this strategy for scaling up EV production and optimizing functional performance for clinical translation.

Mesenchymal stem cell-derived extracellular vesicles in joint diseases: Therapeutic effects and underlying mechanisms

Joint diseases greatly impact the daily lives and occupational functioning of patients globally. However, conventional treatments for joint diseases have several limitations, such as unsatisfatory efficacy and side effects, necessitating the exploration of more efficacious therapeutic strategies. Mesenchymal stem cell (MSC)-derived EVs (MSC-EVs) have demonstrated high therapeutic efficacyin tissue repair and regeneration, with low immunogenicity and tumorigenicity. Recent studies have reported that EVs-based therapy has considerable therapeutic effects against joint diseases, including osteoarthritis, tendon and ligament injuries, femoral head osteonecrosis, and rheumatoid arthritis. Herein, we review the therapeutic potential of various types of MSC-EVs in the aforementioned joint diseases, summarise the mechanisms underlying specific biological effects of MSC-EVs, and discuss future prospects for basic research on MSC-EV-based therapeutic modalities and their clinical translation. In general, this review provides an in-depth understanding of the therapeutic effects of MSC-EVs in joint diseases, as well as the underlying mechanisms, which may be beneficial to the clinical translation of MSC-EV-based treatment. The translational potential of this article: MSC-EV-based cell-free therapy can effectively promote regeneration and tissue repair. When used to treat joint diseases, MSC-EVs have demonstrated desirable therapeutic effects in preclinical research. This review may supplement further research on MSC-EV-based treatment of joint diseases and its clinical translation.

One-step purification and characterization of a haloprotease from Micrococcus sp. PC7 for the production of protein hydrolysates from Andean legumes

The high content and quality of protein in Andean legumes make them valuable for producing protein hydrolysates using proteases from bacteria isolated from extreme environments. This study aimed to carry out a single-step purification of a haloprotease from Micrococcus sp. PC7 isolated from Peru salterns. In addition, characterize and apply the enzyme for the production of bioactive protein hydrolysates from underutilized Andean legumes. The PC7 protease was fully purified using only tangential flow filtration (TFF) and exhibited maximum activity at pH 7.5 and 40 °C. It was characterized as a serine protease with an estimated molecular weight of 130 kDa. PC7 activity was enhanced by Cu2+ (1.7-fold) and remained active in the presence of most surfactants and acetonitrile. Furthermore, it stayed completely active up to 6% NaCl and kept ̴ 60% of its activity up to 8%. The protease maintained over 50% of its activity at 25 °C and 40 °C and over 70% at pH from 6 to 10 for up to 24 h. The determined Km and Vmax were 0.1098 mg mL-1 and 273.7 U mL-1, respectively. PC7 protease hydrolyzed 43%, 22% and 11% of the Lupinus mutabilis, Phaseolus lunatus and Erythrina edulis protein concentrates, respectively. Likewise, the hydrolysates from Lupinus mutabilis and Erythrina edulis presented the maximum antioxidant and antihypertensive activities, respectively. Our results demonstrated the feasibility of a simple purification step for the PC7 protease and its potential to be applied in industrial and biotechnological processes. Bioactive protein hydrolysates produced from Andean legumes may lead to the development of nutraceuticals and functional foods contributing to address some United Nations Sustainable Development Goals (SDGs).

Hydrogel-exosome system in tissue engineering: A promising therapeutic strategy

Characterized by their pivotal roles in cell-to-cell communication, cell proliferation, and immune regulation during tissue repair, exosomes have emerged as a promising avenue for "cell-free therapy" in clinical applications. Hydrogels, possessing commendable biocompatibility, degradability, adjustability, and physical properties akin to biological tissues, have also found extensive utility in tissue engineering and regenerative repair. The synergistic combination of exosomes and hydrogels holds the potential not only to enhance the efficiency of exosomes but also to collaboratively advance the tissue repair process. This review has summarized the advancements made over the past decade in the research of hydrogel-exosome systems for regenerating various tissues including skin, bone, cartilage, nerves and tendons, with a focus on the methods for encapsulating and releasing exosomes within the hydrogels. It has also critically examined the gaps and limitations in current research, whilst proposed future directions and potential applications of this innovative approach.

Proteomics profiling of extracellular vesicle for identification of potential biomarkers in Alzheimer's disease: A comprehensive review

The intricate origins and diverse symptoms of Alzheimer's disease (AD) pose significant challenges for both diagnosis and treatment. Exosomes and microvesicles, which carry disease-specific cargo from a variety of central nervous system cell types, have emerged as promising reservoirs of biomarkers for AD. Research on the screening of possible biomarkers in Alzheimer's disease using proteomic profiling of EVs is systematically reviewed in this comprehensive review. We highlight key methodologies employed in EV isolation, characterization, and proteomic analysis, elucidating their advantages and limitations. Furthermore, we summarize the evolving landscape of EV-associated biomarkers implicated in AD pathogenesis, including proteins involved in amyloid-beta metabolism, tau phosphorylation, neuroinflammation, synaptic dysfunction, and neuronal injury. The literature review highlights the necessity for robust validation strategies and standardized protocols to effectively transition EV-based biomarkers into clinical use. In the concluding section, this review delves into potential future avenues and technological advancements pivotal in crafting EV-derived biomarkers applicable to AD diagnostics and prognostics. This review contributes to our comprehension of AD pathology and the advancement of precision medicine in neurodegenerative diseases, hinting at a promising era in AD precision medicine.

Hydrogel Loaded with Extracellular Vesicles: An Emerging Strategy for Wound Healing

An increasing number of novel biomaterials have been applied in wound healing therapy. Creating beneficial environments and containing various bioactive molecules, hydrogel- and extracellular vesicle (EV)-based therapies have respectively emerged as effective approaches for wound healing. Moreover, the synergistic combination of these two components demonstrates more favorable outcomes in both chronic and acute wound healing. This review provides a comprehensive discussion and summary of the combined application of EVs and hydrogels to address the intricate scenario of wounds. The wound healing process and related biological mechanisms are outlined in the first section. Subsequently, the utilization of EV-loaded hydrogels during the wound healing process is evaluated and discussed. The moist environment created by hydrogels is conducive to wound tissue regeneration. Additionally, the continuous and controlled release of EVs from various origins could be achieved by hydrogel encapsulation. Finally, recent in vitro and in vivo studies reported on hydrogel dressings loaded with EVs are summarized and challenges and opportunities for the future clinical application of this therapeutic approach are outlined.

Circulating B Cell-Derived Small RNA Delivered by Extracellular Vesicles: A Dialogue Mechanism for Long-Range Targeted Renal Mitochondrial Injury in Obesity

The intricate processes that govern the interactions between peripatetic immune cells and distal renal injury in obesity are not fully understood. Employing transcriptomic analysis of circulating extracellular vesicles (EVs), a marked amplification of small RNA (miR-3960) is discerned within CD3-CD19+ B cells. This RNA is found to be preferentially augmented in kidney tissues, contrasting with its subdued expression in other organs. By synthesizing dual-luciferase reporter assay with co-immunoprecipitation analysis, it is pinpointed that miR-3960 specifically targets the nuclear gene TRMT5, a pivotal actor in the methylation of mitochondrial tRNA. This liaison instigates aberrations in the post-transcriptional modifications of mitochondrial tRNA, engendering deficiencies within the electron respiratory chain, primarily attributable to the diminution of the mitochondrial bioenergetic compound (NDUFA7) complex I. Such perturbations lead to a compromised mitochondrial respiratory capacity in renal tubular cells, thereby exacerbating tubular injury. In contrast, EV blockade or miR-3960 depletion markedly alleviates renal tubular injury in obesity. This investigation unveils a hitherto unexplored pathway by which obesity-induced circulating immune cells remotely manipulate mitochondrial metabolism in target organs. The strategic targeting of obese EVs or infiltrative immune cells and their specifically secreted RNAs emerges as a promising therapeutic avenue to forestall obesity-related renal afflictions.

Advances in Extracellular Vesicle Research Over the Past Decade: Source and Isolation Method are Connected with Cargo and Function

The evolution of extracellular vesicle (EV) research has introduced nanotechnology into biomedical cell communication science while recognizing what is formerly considered cell "dust" as constituting an entirely new universe of cell signaling particles. To display the global EV research landscape, a systematic review of 20 364 original research articles selected from all 40 684 EV-related records identified in PubMed 2013-2022 is performed. Machine-learning is used to categorize the high-dimensional data and further dissected significant associations between EV source, isolation method, cargo, and function. Unexpected correlations between these four categories indicate prevalent experimental strategies based on cargo connectivity with function of interest being associated with certain EV sources or isolation strategies. Conceptually relevant association of size-based EV isolation with protein cargo and uptake function will guide strategic conclusions enhancing future EV research and product development. Based on this study, an open-source database is built to facilitate further analysis with conventional or AI tools to identify additional causative associations of interest.

Optimized AF4 combined with density cushion ultracentrifugation enables profiling of high-purity human blood extracellular vesicles

Extracellular vesicles (EVs) have emerged as a promising tool for clinical liquid biopsy. However, the identification of EVs derived from blood samples is hindered by the presence of abundant plasma proteins, which impairs the downstream biochemical analysis of EV-associated proteins and nucleic acids. Here, we employed optimized asymmetric flow field-flow fractionation (AF4) combined with density cushion ultracentrifugation (UC) to obtain high-purity and intact EVs with very low lipoprotein contamination from human plasma and serum. Further proteomic analysis revealed more than 1000 EV-associated proteins, a large proportion of which has not been previously reported. Specifically, we found that cell-line-derived EV markers are incompatible with the identification of plasma-EVs and proposed that the proteins MYCT1, TSPAN14, MPIG6B and MYADM, as well as the traditional EV markers CD63 and CD147, are plasma-EV markers. Benefiting from the high-purity of EVs, we conducted comprehensive miRNA profiling of plasma EVs and nanosized particles (NPs), as well as compared plasma- and serum-derived EVs, which provides a valuable resource for the EV research community. Overall, our findings provide a comprehensive assessment of human blood EVs as a basis for clinical biopsy applications.

Extracellular Vesicles as Mediators of Neuroinflammation in Intercellular and Inter-Organ Crosstalk

Neuroinflammation, crucial in neurological disorders like Alzheimer's disease, multiple sclerosis, and hepatic encephalopathy, involves complex immune responses. Extracellular vesicles (EVs) play a pivotal role in intercellular and inter-organ communication, influencing disease progression. EVs serve as key mediators in the immune system, containing molecules capable of activating molecular pathways that exacerbate neuroinflammatory processes in neurological disorders. However, EVs from mesenchymal stem cells show promise in reducing neuroinflammation and cognitive deficits. EVs can cross CNS barriers, and peripheral immune signals can influence brain function via EV-mediated communication, impacting barrier function and neuroinflammatory responses. Understanding EV interactions within the brain and other organs could unveil novel therapeutic targets for neurological disorders.

Playing pin-the-tail-on-the-protein in extracellular vesicle (EV) proteomics

Extracellular vesicles (EVs) are anucleate particles enclosed by a lipid bilayer that are released from cells via exocytosis or direct budding from the plasma membrane. They contain an array of important molecular cargo such as proteins, nucleic acids, and lipids, and can transfer these cargoes to recipient cells as a means of intercellular communication. One of the overarching paradigms in the field of EV research is that EV cargo should reflect the biological state of the cell of origin. The true relationship or extent of this correlation is confounded by many factors, including the numerous ways one can isolate or enrich EVs, overlap in the biophysical properties of different classes of EVs, and analytical limitations. This presents a challenge to research aimed at detecting low-abundant EV-encapsulated nucleic acids or proteins in biofluids for biomarker research and underpins technical obstacles in the confident assessment of the proteomic landscape of EVs that may be affected by sample-type specific or disease-associated proteoforms. Improving our understanding of EV biogenesis, cargo loading, and developments in top-down proteomics may guide us towards advanced approaches for selective EV and molecular cargo enrichment, which could aid EV diagnostics and therapeutics research.

Role of aptamer technology in extracellular vesicle biology and therapeutic applications

Extracellular vesicles (EVs) are cell-derived nanosized membrane-bound vesicles that are important intercellular signalling regulators in local cell-to-cell and distant cell-to-tissue communication. Their inherent capacity to transverse cell membranes and transfer complex bioactive cargo reflective of their cell source, as well as their ability to be modified through various engineering and modification strategies, have attracted significant therapeutic interest. Molecular bioengineering strategies are providing a new frontier for EV-based therapy, including novel mRNA vaccines, antigen cross-presentation and immunotherapy, organ delivery and repair, and cancer immune surveillance and targeted therapeutics. The revolution of EVs, their diversity as biocarriers and their potential to contribute to intercellular communication, is well understood and appreciated but is ultimately dependent on the development of methods and techniques for their isolation, characterization and enhanced targeting. As single-stranded oligonucleotides, aptamers, also known as chemical antibodies, offer significant biological, chemical, economic, and therapeutic advantages in terms of their size, selectivity, versatility, and multifunctional programming. Their integration into the field of EVs has been contributing to the development of isolation, detection, and analysis pipelines associated with bioengineering strategies for nano-meets-molecular biology, thus translating their use for therapeutic and diagnostic utility.

Glycan Profiling in Small Extracellular Vesicles with a SERS Microfluidic Biosensor Identifies Early Malignant Development in Lung Cancer

Glycosylation is the most common post-translational modification of proteins and regulates a myriad of fundamental biological processes under normal, and pathological conditions. Altered protein glycosylation is linked to malignant transformation, showing distinct glycopatterns that are associated with cancer initiation and progression by regulating tumor proliferation, invasion, metastasis, and therapeutic resistance. The glycopatterns of small extracellular vesicles (sEVs) released by cancer cells are promising candidates for cancer monitoring since they exhibit glycopatterns similar to their cell-of-origin. However, the clinical application of sEV glycans is challenging due to the limitations of current analytical technologies in tracking the trace amounts of sEVs specifically derived from tumors in circulation. Herein, a sEV GLYcan PHenotype (EV-GLYPH) assay that utilizes a microfluidic platform integrated with surface-enhanced Raman scattering for multiplex profiling of sEV glycans in non-small cell lung cancer is clinically validated. For the first time, the EV-GLYPH assay effectively identifies distinct sEV glycan signatures between non-transformed and malignantly transformed lung cells. In a clinical study evaluated on 40 patients, the EV-GLYPH assay successfully differentiates patients with early-stage malignant lung nodules from benign lung nodules. These results reveal the potential to profile sEV glycans for noninvasive diagnostics and prognostics, opening up promising avenues for clinical applications and understanding the role of sEV glycosylation in lung cancer.

The Therapeutic Effects of Blueberry-Treated Stem Cell-Derived Extracellular Vesicles in Ischemic Stroke

An ischemic stroke, one of the leading causes of morbidity and mortality, is caused by ischemia and hemorrhage resulting in impeded blood supply to the brain. According to many studies, blueberries have been shown to have a therapeutic effect in a variety of diseases. Therefore, in this study, we investigated whether blueberry-treated mesenchymal stem cell (MSC)-derived extracellular vesicles (B-EVs) have therapeutic effects in in vitro and in vivo stroke models. We isolated the extracellular vesicles using cryo-TEM and characterized the particles and concentrations using NTA. MSC-derived extracellular vesicles (A-EVs) and B-EVs were round with a lipid bilayer structure and a diameter of ~150 nm. In addition, A-EVs and B-EVs were shown to affect angiogenesis, cell cycle, differentiation, DNA repair, inflammation, and neurogenesis following KEGG pathway and GO analyses. We investigated the protective effects of A-EVs and B-EVs against neuronal cell death in oxygen-glucose deprivation (OGD) cells and a middle cerebral artery occlusion (MCAo) animal model. The results showed that the cell viability was increased with EV treatment in HT22 cells. In the animal, the size of the cerebral infarction was decreased, and the behavioral assessment was improved with EV injections. The levels of NeuN and neurofilament heavy chain (NFH)-positive cells were also increased with EV treatment yet decreased in the MCAo group. In addition, the number of apoptotic cells was decreased with EV treatment compared with ischemic animals following TUNEL and Bax/Bcl-2 staining. These data suggested that EVs, especially B-EVs, had a therapeutic effect and could reduce apoptotic cell death after ischemic injury.

Analysis of secreted small extracellular vesicles from activated human microglial cell lines reveals distinct pro- and anti-inflammatory proteomic profiles

Microglia are a specialized population of innate immune cells located in the central nervous system. In response to physiological and pathological changes in their microenvironment, microglia can polarize into pro-inflammatory or anti-inflammatory phenotypes. A dysregulation in the pro-/anti-inflammatory balance is associated with many pathophysiological changes in the brain and nervous system. Therefore, the balance between microglia pro-/anti-inflammatory polarization can be a potential biomarker for the various brain pathologies. A non-invasive method of detecting microglia polarization in patients would have promising clinical applications. Here, we perform proteomic analysis of small extracellular vesicles (sEVs) derived from microglia cells to identify sEVs biomarkers indicative of pro-inflammatory and anti-inflammatory phenotypic changes. sEVs were isolated from microglia cell lines under different inflammatory conditions and analyzed by proteomics by liquid chromatography with mass spectrometry. Our findings provide the potential roles of sEVs that could be related to the pathogenesis of various brain diseases.

Small extracellular vesicles' enrichment from biological fluids using an acoustic trap

Small extracellular vesicles (sEVs), a form of extracellular vesicles, are lipid bilayered structures released by all cells. Large-scale studies on sEVs from clinical samples are necessary, but a major obstacle is the lack of rapid, reproducible, efficient, and low-cost methods to enrich sEVs. Acoustic microfluidics have the advantage of being label-free and biocompatible, which have been reported to successfully enrich sEVs. In this paper, we present a highly efficient acoustic microfluidic trap that can offer low and large volume compatible ways of enriching sEVs from biological fluids by flexible structure design. It uses the idea of pre-loading larger seed particles in the acoustic trap to enable sub-micron particle capturing. The microfluidic chip is actuated using a piezoelectric plate transducer attached to a silicon-glass bonding plate with circular cavities. Each cavity works as a resonant unit, excited at the frequency of both the half wave resonance in the main plane and inverted quarter wave resonance in the depth direction, which has the ability to strongly trap seed particles at the center, thereby improving the subsequent nanoparticle capture efficiency. Mean trapping efficiencies of 35.62% and 64.27% were obtained using 60 nm and 100 nm nanobeads, respectively. By the use of this technology, we have successfully enriched sEVs from cell culture conditioned media and blood plasma at a flow rate of 10 μL min-1. The isolated sEV subpopulations are characterized by NTA and TEM, and their protein cargo is determined by WB. This acoustic trapping chip provides a rapid and robust method to enrich sEVs from biofluids with high reproducibility and sufficient quantities. Therefore, it can serve as a new tool for biological and clinical research such as cancer diagnosis and drug delivery.

Extracellular vesicles from dental pulp mesenchymal stem cells modulate macrophage phenotype during acute and chronic cardiac inflammation in athymic nude rats with myocardial infarction

BACKGROUND/AIMS

Extracellular vesicles (EVs) derived from dental pulp mesenchymal stem cells (DP-MSCs) are a promising therapeutic option for the treatment of myocardial ischemia. The aim of this study is to determine whether MSC-EVs could promote a pro-resolving environment in the heart by modulating macrophage populations.

METHODS

EVs derived from three independent biopsies of DP-MSCs (MSC-EVs) were isolated by tangential flow-filtration and size exclusion chromatography and were characterized by omics analyses. Biological processes associated with these molecules were analyzed using String and GeneCodis platforms. The immunomodulatory capacity of MSC-EVs to polarize macrophages towards a pro-resolving or M2-like phenotype was assessed by evaluating surface markers, cytokine production, and efferocytosis. The therapeutic potential of MSC-EVs was evaluated in an acute myocardial infarction (AMI) model in nude rats. Infarct size and the distribution of macrophage populations in the infarct area were evaluated 7 and 21 days after intramyocardial injection of MSC-EVs.

RESULTS

Lipidomic, proteomic, and miRNA-seq analysis of MSC-EVs revealed their association with biological processes involved in tissue regeneration and regulation of the immune system, among others. MSC-EVs promoted the differentiation of pro-inflammatory macrophages towards a pro-resolving phenotype, as evidenced by increased expression of M2 markers and decreased secretion of pro-inflammatory cytokines. Administration of MSC-EVs in rats with AMI limited the extent of the infarcted area at 7 and 21 days post-infarction. MSC-EV treatment also reduced the number of pro-inflammatory macrophages within the infarct area, promoting the resolution of inflammation.

CONCLUSION

EVs derived from DP-MSCs exhibited similar characteristics at the omics level irrespective of the biopsy from which they were derived. All MSC-EVs exerted effective pro-resolving responses in a rat model of AMI, indicating their potential as therapeutic agents for the treatment of inflammation associated with AMI.

Development of a Sampling and Storage Protocol of Extracellular Vesicles (EVs)-Establishment of the First EV Biobank for Polytraumatized Patients

In the last few years, several studies have emphasized the existence of injury-specific EV "barcodes" that could have significant importance for the precise diagnosis of different organ injuries in polytrauma patients. To expand the research potential of the NTF (network trauma research) biobank of polytraumatized patients, the NTF research group decided to further establish a biobank for EVs. However, until now, the protocols for the isolation, characterization, and storage of EVs for biobank purposes have not been conceptualized. Plasma and serum samples from healthy volunteers (n = 10) were used. Three EV isolation methods of high relevance for the work with patients' samples (ultracentrifugation, size exclusion chromatography, and immune magnetic bead-based isolation) were compared. EVs were quantified using nanoparticle tracking analysis, EV proteins, and miRNAs. The effects of different isolation solutions; the long storage of samples (up to 3 years); and the sensibility of EVs to serial freezing-thawing cycles and different storage conditions (RT, 4/-20/-80 °C, dry ice) were evaluated. The SEC isolation method was considered the most suitable for EV biobanking. We did not find any difference in the quantity of EVs between serum and plasma-EVs. The importance of particle-free PBS as an isolation solution was confirmed. Plasma that has been frozen for a long time can also be used as a source of EVs. Serial freezing-thawing cycles were found to affect the mean size of EVs but not their amount. The storage of EV samples for 5 days on dry ice significantly reduced the EV protein concentration.

Functional extracellular vesicles from SHEDs combined with gelatin methacryloyl promote the odontogenic differentiation of DPSCs for pulp regeneration

BACKGROUND

Pulp regeneration is a novel approach for the treatment of immature permanent teeth with pulp necrosis. This technique includes the combination of stem cells, scaffolds, and growth factors. Recently, stem cell-derived extracellular vesicles (EVs) have emerged as a new methodology for pulp regeneration. Emerging evidence has proven that preconditioning is an effective scheme to modify EVs for better therapeutic potency. Meanwhile, proper scaffolding is of great significance to protect EVs from rapid clearance and destruction. This investigation aims to fabricate an injectable hydrogel loaded with EVs from pre-differentiated stem cells from human exfoliated deciduous teeth (SHEDs) and examine their effects on pulp regeneration.

RESULTS

We successfully employed the odontogenic induction medium (OM) of SHEDs to generate functional EV (OM-EV). The OM-EV at a concentration of 20 µg/mL was demonstrated to promote the proliferation and migration of dental pulp stem cells (DPSCs). The results revealed that OM-EV has a better potential to promote odontogenic differentiation of DPSCs than common EVs (CM-EV) in vitro through Alizarin red phalloidin, alkaline phosphatase staining, and assessment of the expression of odontogenic-related markers. High-throughput sequencing suggests that the superior effects of OM-EV may be attributed to activation of the AMPK/mTOR pathway. Simultaneously, we prepared a photocrosslinkable gelatin methacryloyl (GelMA) to construct an OM-EV-encapsulated hydrogel. The hydrogel exhibited sustained release of OM-EV and good biocompatibility for DPSCs. The released OM-EV from the hydrogel could be internalized by DPSCs, thereby enhancing their survival and migration. In tooth root slices that were subcutaneously transplanted in nude mice, the OM-EV-encapsulated hydrogel was found to facilitate dentinogenesis. After 8 weeks, there was more formation of mineralized tissue, as well as higher levels of dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1).

CONCLUSIONS

The effects of EV can be substantially enhanced by preconditioning of SHEDs. The functional EVs from SHEDs combined with GelMA are capable of effectively promoting dentinogenesis through upregulating the odontogenic differentiation of DPSCs, which provides a promising therapeutic approach for pulp regeneration.

A novel multi-stage enrichment workflow and comprehensive characterization for HEK293F-derived extracellular vesicles

Extracellular vesicles (EVs) are emerging as a promising drug delivery vehicle as they are biocompatible and capable of targeted delivery. However, clinical translation of EVs remains challenging due to the lack of standardized and scalable manufacturing protocols to consistently isolate small EVs (sEVs) with both high yield and high purity. The heterogenous nature of sEVs leading to unknown composition of biocargos causes further pushback due to safety concerns. In order to address these issues, we developed a robust quality-controlled multi-stage process to produce and isolate sEVs from human embryonic kidney HEK293F cells. We then compared different 2-step and 3-step workflows for eliminating protein impurities and cell-free nucleic acids to meet acceptable limits of regulatory authorities. Our results showed that sEV production was maximized when HEK293F cells were grown at high-density stationary phase in semi-continuous culture. The novel 3-step workflow combining tangential flow filtration, sucrose-cushion ultracentrifugation and bind-elute size-exclusion chromatography outperformed other methods in sEV purity while still preserved high yield and particle integrity. The purified HEK293F-derived sEVs were thoroughly characterized for identity including sub-population analysis, content profiling including proteomics and miRNA sequencing, and demonstrated excellent preclinical safety profile in both in-vitro and in-vivo testing. Our rigorous enrichment workflow and comprehensive characterization will help advance the development of EVs, particularly HEK293F-derived sEVs, to be safe and reliable drug carriers for therapeutic applications.

Albumen exosomes alleviate LPS-induced inflammation of intestinal epithelial cells via miR-22/ATM/p53/NF-κB axis

Biological macromolecules identified in albumen were found benefit to intestinal health, whether albumen contains exosomes and function of their cargos in intestinal inflammation remain unknown. This study aimed to investigate characteristics and cargos of albumen exosomes, as well as their potential roles in alleviating inflammation in intestinal epithelial cells. Our results demonstrated that albumen contains exosomes that are cup-shaped morphology vesicles with diameter ranging from 50 to 200 nm. There were 278 miRNAs and 45 proteins with higher expression levels in albumen exosomes, and they were mainly involved in immune responses and programmed cell death pathways, including apoptosis and p53 signaling pathway. LPS induced overexpression of pro-inflammatory cytokines IL-1β and TNF-α and excessive apoptosis, which could be reversed by albumen exosomes. The beneficial effects of exosomes could be mainly attributed to miRNA cargos and their inhibition on inflammatory response signaling pathways (p53 and NF-κB pathways). Mechanically, exosome miR-22 targeted ATM and inhibited p53/NF-κB pathway, alleviating LPS-induced overexpression of Caspase-3 and Bax, and inflammatory response. Collectively, albumen exosomes alleviate inflammation of intestinal epithelial cells via miR-22/ATM/p53/NF-κB axis and these findings may provide theoretical basis to the potential application of albumen exosomes for intestinal inflammation.

Exosomes in the pathogenesis and treatment of cancer-related cachexia

Cancer-related cachexia is a metabolic syndrome characterized by weight loss, adipose tissue decomposition, and progressive skeletal muscle atrophy. It is a major complication of many advanced cancers and seriously affects the quality of life and survival of cancer patients. However, the specific molecules that mediate cancer-related cachexia remain elusive, and the fundamental cellular and molecular mechanisms associated with muscle atrophy and lipidolysis in cancer patients still need to be investigated. Exosomes, a newly discovered class of small extracellular vesicles that facilitate intercellular communication, have a significant role in the onset and development of various cancers. Studies have shown that exosomes play a role in the onset and progression of cancer-related cachexia by transporting active molecules such as nucleic acids and proteins. This review aimed to provide an overview of exosome developments in cancer-induced skeletal muscle atrophy and adipose tissue degradation. More importantly, exosomes were shown to have potential as diagnostic markers or therapeutic strategies for cachexia and were prospected, providing novel strategies for the diagnosis and treatment of cancer-related cachexia.

Extracellular vesicles in endometriosis: role and potential

Endometriosis is a chronic inflammatory gynecological disease, which profoundly jeopardizes women's quality of life and places a significant medical burden on society. The pathogenesis of endometriosis remains unclear, posing major clinical challenges in diagnosis and treatment. There is an urgent demand for the development of innovative non-invasive diagnostic techniques and the identification of therapeutic targets. Extracellular vesicles, recognized for transporting a diverse array of signaling molecules, have garnered extensive attention as a novel mode of intercellular communication. A burgeoning body of research indicates that extracellular vesicles play a pivotal role in the pathogenesis of endometriosis, which may provide possibility and prospect for both diagnosis and treatment. In light of this context, this article focuses on the involvement of extracellular vesicles in the pathogenesis of endometriosis, which deliver information among endometrial stromal cells, macrophages, mesenchymal stem cells, and other cells, and explores their potential applications in the diagnosis and treatment, conducing to the emergence of new strategies for clinical diagnosis and treatment.

Tumor-derived extracellular vesicles regulate macrophage polarization: role and therapeutic perspectives

Extracellular vesicles (EVs) are important cell-to-cell communication mediators. This paper focuses on the regulatory role of tumor-derived EVs on macrophages. It aims to investigate the causes of tumor progression and therapeutic directions. Tumor-derived EVs can cause macrophages to shift to M1 or M2 phenotypes. This indicates they can alter the M1/M2 cell ratio and have pro-tumor and anti-inflammatory effects. This paper discusses several key points: first, the factors that stimulate macrophage polarization and the cytokines released as a result; second, an overview of EVs and the methods used to isolate them; third, how EVs from various cancer cell sources, such as hepatocellular carcinoma, colorectal carcinoma, lung carcinoma, breast carcinoma, and glioblastoma cell sources carcinoma, promote tumor development by inducing M2 polarization in macrophages; and fourth, how EVs from breast carcinoma, pancreatic carcinoma, lungs carcinoma, and glioblastoma cell sources carcinoma also contribute to tumor development by promoting M2 polarization in macrophages. Modified or sourced EVs from breast, pancreatic, and colorectal cancer can repolarize M2 to M1 macrophages. This exhibits anti-tumor activities and offers novel approaches for tumor treatment. Therefore, we discovered that macrophage polarization to either M1 or M2 phenotypes can regulate tumor development. This is based on the description of altering macrophage phenotypes by vesicle contents.

BMP7-Loaded Human Umbilical Cord Mesenchymal Stem Cell-Derived Small Extracellular Vesicles Ameliorate Liver Fibrosis by Targeting Activated Hepatic Stellate Cells

Purpose

Human umbilical cord mesenchymal stem cell (hucMSC)-derived small extracellular vesicles (sEVs) are natural nanocarriers with promising potential in treating liver fibrosis and have widespread applications in the fields of nanomedicine and regenerative medicine. However, the therapeutic efficacy of natural hucMSC-sEVs is currently limited owing to their non-specific distribution in vivo and partial removal by mononuclear macrophages following systemic delivery. Thus, the therapeutic efficacy can be improved through the development of engineered hucMSC-sEVs capable to overcome these limitations.

Patients and Methods

To improve the anti-liver fibrosis efficacy of hucMSC-sEVs, we genetically engineered hucMSC-sEVs to overexpress the anti-fibrotic gene bone morphogenic protein 7 (BMP7) in parental cells. This was achieved using lentiviral transfection, following which BMP7-loaded hucMSC-sEVs were isolated through ultracentrifugation. First, the liver fibrosis was induced in C57BL/6J mice by intraperitoneal injection of 50% carbon tetrachloride (CCL4) twice a week for 8 weeks. These mice were subsequently treated with BMP7+sEVs via tail vein injection, and the anti-liver fibrosis effect of BMP7+sEVs was validated using small animal in vivo imaging, immunohistochemistry (IHC), tissue immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Finally, cell function studies were performed to confirm the in vivo results.

Results

Liver imaging and liver histopathology confirmed that the engineered hucMSC-sEVs could reach the liver of mice and aggregate around activated hepatic stellate cells (aHSCs) with a significantly stronger anti-liver fibrosis effect of BMP7-loaded hucMSC-sEVs compared to those of blank or negative control-transfected hucMSC-sEVs. In vitro, BMP7-loaded hucMSC-sEVs promoted the phenotypic reversal of aHSCs and inhibited their proliferation to enhance the anti-fibrotic effects.

Conclusion

These engineered BMP7-loaded hucMSC-sEVs offer a novel and promising strategy for the clinical treatment of liver fibrosis.

Milk Extracellular Vesicles: Natural Nanoparticles for Enhancing Oral Drug Delivery against Bacterial Infections

Oral drug delivery is typically preferred as a therapeutic intervention due to the complexities and expenses associated with intravenous administration. However, some drugs are poorly absorbed orally, requiring intravenous administration to bypass the gastrointestinal tract and deliver the drug directly into the bloodstream. Thus, there is an urgent need to develop novel drug delivery platforms to overcome the challenges of oral drug delivery with low solubility, low permeability, oral degradation, and low bioavailability. Advances in extracellular vesicles (EVs) as natural carriers have provided emerging approaches to improve potential therapeutic applications. Milk not only contains traditional nutrients but is also rich in EVs. In this Review, we focus mainly on the purification of milk EVs (mEVs), their safety, and the advantages of mEV-based drug carriers in combatting intestinal infections. Additionally, we summarize several advantages of mEVs over conventional synthetic carriers, such as low immunogenicity, high biocompatibility, and the ability to transfer bioactive molecules between cells. Considering the unmet gaps of mEVs in clinical translation, it is essential to review the cargo loading into mEVs and future perspectives for their use as natural drug carriers for oral delivery. This overview of mEV-based drug carriers for oral delivery sheds light on alternative approaches to treat clinical infections associated with intestinal pathogens and the development of novel oral delivery systems.

Extracellular-Vesicle Catch-and-Release Isolation System Using a Net-Charge Invertible Curvature-Sensing Peptide

Extracellular vesicles (EVs) carry various informative components, including signaling proteins, transcriptional regulators, lipids, and nucleic acids. These components are utilized for cell-cell communication between donor and recipient cells. EVs have shown great promise as pharmaceutical-targeting vesicles and have attracted the attention of researchers in the fields of biological and medical science because of their importance as diagnostic and prognostic markers. However, the isolation and purification of EVs from cell-cultured media remain challenging. Ultracentrifugation is the most widely used method, but it requires specialized and expensive equipment. In the present study, we proposed a novel methodology to isolate EVs using a simple and convenient method, i.e., an EV catch-and-release isolation system (EV-CaRiS) using a net-charge invertible curvature-sensing peptide (NIC). Curvature-sensing peptides recognize vesicles by binding to lipid-packing defects on highly curved membranes regardless of the expression levels of biomarkers. NIC was newly designed to reversibly capture and release EVs in a pH-dependent manner. NIC allowed us to achieve reproducible EV isolation from three human cell lines on resin using a batch method and single-particle imaging of EVs containing the ubiquitous exosome markers CD63 and CD81 by total internal reflection fluorescence microscopy (TIRFM). EV-CaRiS was demonstrated as a simple and convenient methodology for EV isolation, and NIC is promising for applications in the single-particle analysis of EVs.

Harnessing the power of goat milk-derived extracellular vesicles for medical breakthroughs: A review

Research into goat milk-derived extracellular vesicles (GMVs) has grown in popularity in recent years owing to their potential uses in several sectors, including medicine. GMVs are tiny, lipid-bound structures that cells secrete and use to transport bioactive substances like proteins, lipids, and nucleic acids. They may be extracted from different body fluids, including blood, urine, and milk, and have been found to play crucial roles in cell-to-cell communication. GMVs are a promising field of study with applications in preventing and treating various disorders. Their immune-modulating properties, for instance, have been investigated, and they have shown promise in treating autoimmune illnesses and cancer. They may be loaded with therapeutic compounds and directed to particular cells or tissues, but they have also been studied for their potential use as drug-delivery vehicles. Goat milk extracellular vesicles are an intriguing study topic with many possible benefits. Although more study is required to thoroughly understand their functioning and prospective applications, they provide a promising path for creating novel medical treatments and technology.

Isolation of small extracellular vesicles from regenerating muscle tissue using Tangential Flow Filtration and Size Exclusion Chromatography

We have recently made the strikingly discovery that upon a muscle injury, Wnt7a is upregulated and secreted from new regenerating myofibers on the surface of exosomes to elicit its myogenerative response distally. Despite recent advances in extracellular vesicle (EVs) isolation from diverse tissues, there is still a lack of specific methodology to purify EVs from muscle tissue. To eliminate contamination with non-EV secreted proteins and cytoplasmic fragments, which are typically found when using classical methodology, such as ultracentrifugation, we adapted a protocol combining Tangential Flow Filtration (TFF) and Size Exclusion Chromatography (SEC). We found that this approach allows simultaneous purification of Wnt7a, bound to EVs (retentate fraction) and free non-EV Wnt7a (permeate fraction). Here we described this optimized protocol designed to specifically isolate EVs from hind limb muscle explants, without cross-contamination with other sources of non-EV bounded proteins. The first step of the protocol is to remove large EVs with sequential centrifugation. Extracellular vesicles are then concentrated and washed in exchange buffer by TFF. Lastly, SEC is performed to remove any soluble protein traces remaining after TFF. Overall, this procedure can be used to isolate EVs from conditioned media or biofluid that contains EVs derived from any cell type or tissue, improving reproducibility, efficiency, and purity of EVs preparations. Our purification protocol results in high purity EVs that maintain structural integrity and thus fully compatible with in vitro and in vivo bioactivity and analytic assays.

Skin rejuvenation and photoaging protection using adipose-derived stem cell extracellular vesicles loaded with exogenous cargos

BACKGROUND

Small extracellular vesicles from adipose-derived stem cells (ASC-sEVs) have gained remarkable attention for their regenerative and protective properties against skin aging. However, the use of ASC-sEVs to further encapsulate certain natural anti-aging compounds for synergistic effects has not been actively explored. For large-scale production in skincare industry, it is also crucial to standardize cost-effective methods to produce highly pure ASC-sEVs.

METHODS

Human ASCs were expanded in serum-free media with different compositions to first optimize the sEV production. ASC-sEVs from different batches were then purified using tangential flow filtration and sucrose cushion ultracentrifugation, followed by extensive characterization for identity and content profiling including proteomics, lipidomics and miRNA sequencing. ASC-sEVs were further loaded with nicotinamide riboside (NR) and resveratrol by sonication-incubation method. The therapeutic effect of ASC-sEVs and loaded ASC-sEVs was tested on human keratinocyte cell line HaCaT exposed to UVB by measuring reactive oxygen species (ROS). The loaded ASC-sEVs were later applied on the hand skin of three volunteers once a day for 8 weeks and skin analysis was performed every 2 weeks.

RESULTS

Our standardized workflow produced ASC-sEVs with high yield, high purity and with stable characteristics and consistent biocargo among different batches. The most abundant subpopulations in ASC-sEVs were CD63+ (∼30%) and CD81+ -CD63+ (∼35%). Purified ASC-sEVs could be loaded with NR and resveratrol at the optimized loading efficiency of ∼20%. In UVB-exposed HaCaT cells, loaded ASC-sEVs could reduce ROS by 38.3%, higher than the sEVs (13.3%) or compounds (18.5%) individually. In human trial, application of loaded ASC-sEVs after 8 weeks substantially improved skin texture, increased skin hydration and elasticity by 104% and reduced mean pore volume by 51%.

CONCLUSIONS

This study demonstrated a robust protocol to produce ASC-sEVs and exogenously load them with natural compounds. The loaded ASC-sEVs exhibited synergistic effects of both sEVs and anti-aging compounds in photoaging protection and skin rejuvenation.

Emerging role of extracellular vesicles in veterinary practice: novel opportunities and potential challenges

Extracellular vesicles are nanoscale vesicles that transport signals between cells, mediating both physiological and pathological processes. EVs facilitate conserved intercellular communication. By transferring bioactive molecules between cells, EVs coordinate systemic responses, regulating homeostasis, immunity, and disease progression. Given their biological importance and involvement in pathogenesis, EVs show promise as biomarkers for veterinary diagnosis, and candidates for vaccine production, and treatment agents. Additionally, different treatment or engineering methods could be used to boost the capability of extracellular vesicles. Despite the emerging veterinary interest, EV research has been predominantly human-based. Critical knowledge gaps remain regarding isolation protocols, cargo loading mechanisms, in vivo biodistribution, and species-specific functions. Standardized methods for veterinary EV characterization and validation are lacking. Regulatory uncertainties impede veterinary clinical translation. Advances in fundamental EV biology and technology are needed to propel the veterinary field forward. This review introduces EVs from a veterinary perspective by introducing the latest studies, highlighting their potential while analyzing challenges to motivate expanded veterinary investigation and translation.

Tracking the EMT-like phenotype switching during targeted therapy in melanoma by analyzing extracellular vesicle phenotypes

Melanoma continues to be a leading cause of mortality among skin cancers. Despite advancements in targeted therapy, patients frequently develop resistance, leading to disease progression within a year. This resistance may result from the epithelial-to-mesenchymal transition (EMT)-like phenotype switching of melanoma cells. Tracking EMT-related phenotypic changes on extracellular vesicles (EVs) has potential to inform early about response to targeted therapy and melanoma progression. However, the knowledge on protein biomarkers carried by melanoma EVs involved in the EMT-like process remains unexplored. Herein, we present a biosensor integrating surface-enhanced Raman scattering and alternating current electrohydrodynamics-induced nanomixing enhancement, for sensitive detection of EMT-associated biomarkers on EV surfaces during targeted therapy. This biosensor successfully tracks the EMT-like phenotype switching in melanoma cell lines treated with mitogen-activated protein kinase inhibitor (MAPKi). Longitudinal monitoring of patients who receive MAPKi therapy and develop resistance, our biosensor shows its ability to identify the EMT-like phenotype switching on circulating EVs. This ability potentially can be leveraged to predict the development of resistance to targeted therapy, allowing for timely intervention and personalized treatment strategies.

Rigorous Comparison of Extracellular Vesicle Processing to Enhance Downstream Analysis for Glioblastoma Characterization

Extracellular vesicles (EVs) are highly sought after as a source of biomarkers for disease detection and monitoring. Tumor EV isolation, processing, and evaluation from biofluids is convoluted by EV heterogeneity and biological contaminants and is limited by technical processing efficacy. This study rigorously compares common bulk EV isolation workflows (size exclusion chromatography, SEC; membrane affinity, MA) alongside downstream RNA extraction protocols to investigate molecular analyte recovery. EV integrity and recovery is evaluated using a variety of technologies to quantify total intact EVs, total and surface proteins, and RNA purity and recovery. A comprehensive evaluation of each analyte is performed, with a specific emphasis on maintaining user (n = 2), biological (n = 3), and technical replicates (n≥3) under in vitro conditions. Subsequent study of tumor EV spike-in into healthy donor plasma samples is performed to further validate biofluid-derived EV purity and isolation for clinical application. Results show that EV surface integrity is considerably preserved in eluates from SEC-derived EVs, but RNA recovery and purity, as well as bulk protein isolation, is significantly improved in MA-isolated EVs. This study concludes that EV isolation and RNA extraction pipelines govern recovered analyte integrity, necessitating careful selection of processing modality to enhance recovery of the analyte of interest.

Extracellular vesicles from organoid-derived human retinal progenitor cells prevent lipid overload-induced retinal pigment epithelium injury by regulating fatty acid metabolism

Retinal degeneration (RD), a group of diseases leading to irreversible vision loss, is characterised by retinal pigment epithelium (RPE) or retinal neuron damage and loss. With fewer risks of immune rejection and tumorigenesis, stem cell-secreted extracellular vesicles (EVs) offer a new cell-free therapeutic paradigm for RD, which remains to be investigated. Human retinal organoid-derived retinal progenitor cells (hERO-RPCs) are an easily accessible and advanced cell source for RD treatment. However, hERO-RPCs-derived EVs require further characterisation. Here, we compared the characteristics of EVs from hERO-RPCs (hRPC-EVs) with those of human embryonic stem cell (hESC)-derived EVs (hESC-EVs) as controls. Based on in-depth proteomic analysis, we revealed remarkable differences between hRPC-EVs and hESC-EVs. A comparison between EVs and their respective cells of origin demonstrated that the protein loading of hRPC-EVs was more selective than that of hESC-EVs. In particular, hESC-EVs were enriched with proteins related to angiogenesis and cell cycle, whereas hRPC-EVs were enriched with proteins associated with immune modulation and retinal development. More importantly, compared with that of hESC-EVs, hRPC-EVs exhibited a lower correlation with cell proliferation and a unique capacity to regulate lipid metabolism. It was further confirmed that hRPC-EVs potentially eliminated lipid deposits, inhibited lipotoxicity and oxidative stress, and enhanced phagocytosis and survival of oleic acid-treated ARPE-19 cells. Mechanistically, hRPC-EVs are integrated into the mitochondrial network of oleic acid-treated ARPE-19 cells, and increased the level of mitochondrial fatty acid β-oxidation-related proteins. Thus, organoid-derived hRPC-EVs represent a promising source of cell-free therapy for RD, especially for blinding diseases related to abnormal lipid metabolism in RPE cells.

Recommendations for reproducibility of cerebrospinal fluid extracellular vesicle studies

Cerebrospinal fluid (CSF) is a clear, transparent fluid derived from blood plasma that protects the brain and spinal cord against mechanical shock, provides buoyancy, clears metabolic waste and transports extracellular components to remote sites in the brain. Given its contact with the brain and the spinal cord, CSF is the most informative biofluid for studies of the central nervous system (CNS). In addition to other components, CSF contains extracellular vesicles (EVs) that carry bioactive cargoes (e.g., lipids, nucleic acids, proteins), and that can have biological functions within and beyond the CNS. Thus, CSF EVs likely serve as both mediators of and contributors to communication in the CNS. Accordingly, their potential as biomarkers for CNS diseases has stimulated much excitement for and attention to CSF EV research. However, studies on CSF EVs present unique challenges relative to EV studies in other biofluids, including the invasive nature of CSF collection, limited CSF volumes and the low numbers of EVs in CSF as compared to plasma. Here, the objectives of the International Society for Extracellular Vesicles CSF Task Force are to promote the reproducibility of CSF EV studies by providing current reporting and best practices, and recommendations and reporting guidelines, for CSF EV studies. To accomplish this, we created and distributed a world-wide survey to ISEV members to assess methods considered 'best practices' for CSF EVs, then performed a detailed literature review for CSF EV publications that was used to curate methods and resources. Based on responses to the survey and curated information from publications, the CSF Task Force herein provides recommendations and reporting guidelines to promote the reproducibility of CSF EV studies in seven domains: (i) CSF Collection, Processing, and Storage; (ii) CSF EV Separation/Concentration; (iii) CSF EV Size and Number Measurements; (iv) CSF EV Protein Studies; (v) CSF EV RNA Studies; (vi) CSF EV Omics Studies and (vii) CSF EV Functional Studies.

A clinically relevant large-scale biomanufacturing workflow to produce natural killer cells and natural killer cell-derived extracellular vesicles for cancer immunotherapy

Natural killer cell-derived extracellular vesicles (NK-EVs) have shown promising potential as biotherapeutics for cancer due to their unique attributes as cytotoxic nanovesicles against cancer cells and immune-modulatory activity towards immune cells. However, a biomanufacturing workflow is needed to produce clinical-grade NK-EVs for pre-clinical and clinical applications. This study established a novel biomanufacturing workflow using a closed-loop hollow-fibre bioreactor to continuously produce NK-EVs from the clinically relevant NK92-MI cell line under serum-free, Xeno-free and feeder-free conditions following GMP-compliant conditions. The NK92 cells grown in the bioreactor for three continuous production lots resulted in large quantities of both NK cell and NK-EV biotherapeutics at the end of each production lot (over 109 viable cells and 1013 EVs), while retaining their cytotoxic payload (granzyme B and perforin), pro-inflammatory cytokine (interferon-gamma) content and cytotoxicity against the human leukemic cell line K562 with limited off-target toxicity against healthy human fibroblast cells. This scalable biomanufacturing workflow has the potential to facilitate the clinical translation of adoptive NK cell-based and NK-EV-based immunotherapies for cancer with GMP considerations.

Engineered exosomes for tissue regeneration: from biouptake, functionalization and biosafety to applications

Exosomes are increasingly recognized as important effector molecules that regulate intercellular signaling pathways. Notably, certain types of exosomes can induce therapeutic responses, including cell proliferation, angiogenesis, and tissue repair. The use of exosomes in therapy is a hot spot in current research, especially in regenerative medicine. Despite the therapeutic potential, problems have hindered their success in clinical applications. These shortcomings include low concentration, poor targeting and limited loading capability. To fully realize their therapeutic potential, certain modifications are needed in native exosomes. In the present review, we summarize the exosome modification and functionalization strategies. In addition, we provide an overview of potential clinical applications and highlight the issues associated with the biosafety and biocompatibility of engineered exosomes in applications.

C1q is increased in cerebrospinal fluid-derived extracellular vesicles in Alzheimer's disease: A multi-cohort proteomics and immuno-assay validation study

INTRODUCTION

Extracellular vesicles (EVs) may propagate and modulate Alzheimer's disease (AD) pathology. We aimed to comprehensively characterize the proteome of cerebrospinal fluid (CSF) EVs to identify proteins and pathways altered in AD.

METHODS

CSF EVs were isolated by ultracentrifugation (Cohort 1) or Vn96 peptide (Cohort 2) from non-neurodegenerative controls (n = 15, 16) and AD patients (n = 22, 20, respectively). EVs were subjected to untargeted quantitative mass spectrometry-based proteomics. Results were validated by enzyme-linked immunosorbent assay (ELISA) in Cohorts 3 and 4, consisting of controls (n = 16, n = 43, (Cohort3, Cohort4)), and patients with AD (n = 24, n = 100).

RESULTS

We found > 30 differentially expressed proteins in AD CSF EVs involved in immune-regulation. Increase of C1q levels in AD compared to non-demented controls was validated by ELISA (∼ 1.5 fold, p (Cohort 3) = 0.03, p (Cohort 4) = 0.005).

DISCUSSION

EVs may be utilized as a potential biomarker and may play a so far unprecedented role in immune-regulation in AD.

Analysis of distribution, collection, and confirmation of capacity dependency of small extracellular vesicles toward a therapy for liver cirrhosis

BACKGROUND

The progression of liver fibrosis leads to portal hypertension and liver dysfunction. However, no antifibrotic agents have been approved for cirrhosis to date, making them an unmet medical need. Small extracellular vesicles (sEVs) of mesenchymal stem cells (MSCs) are among these candidate agents. In this study, we investigated the effects of sEVs of MSCs, analyzed their distribution in the liver post-administration, whether their effect was dose-dependent, and whether it was possible to collect a large number of sEVs.

METHODS

sEVs expressing tdTomato were generated, and their uptake into constituent liver cells was observed in vitro, as well as their sites of uptake and cells in the liver using a mouse model of liver cirrhosis. The efficiency of sEV collection using tangential flow filtration (TFF) and changes in the therapeutic effects of sEVs in a volume-dependent manner were examined.

RESULTS

The sEVs of MSCs accumulated mostly in macrophages in damaged areas of the liver. In addition, the therapeutic effect of sEVs was not necessarily dose-dependent, and it reached a plateau when the dosage exceeded a certain level. Furthermore, although ultracentrifugation was commonly used to collect sEVs for research purposes, we verified that TFF could be used for efficient sEV collection and that their effectiveness is not reduced.

CONCLUSION

In this study, we identified some unknown aspects regarding the dynamics, collection, and capacity dependence of sEVs. Our results provide important fundamentals for the development of therapies using sEVs and hold potential implications for the therapeutic applications of sEV-based therapies for liver cirrhosis.

Engineered exosomes as drug and RNA co-delivery system: new hope for enhanced therapeutics?

Chemotherapy often faces some obstacles such as low targeting effects and drug resistance, which introduce the low therapeutic efficiency and strong side effects. Recent advances in nanotechnology allows the use of novel nanosystems for targeted drug delivery, although the chemically synthesized nanomaterials always show unexpected low biocompability. The emergence of exosome research has offered a better understanding of disease treatment and created novel opportunities for developing effective drug delivery systems with high biocompability. Moreover, RNA interference has emerged as a promising strategy for disease treatments by selectively knocking down or over-expressing specific genes, which allows new possibilities to directly control cell signaling events or drug resistance. Recently, more and more interests have been paid to develop optimal delivery nanosystems with high efficiency and high biocompability for drug and functional RNA co-delivery to achieve enhanced chemotherapy. In light of the challenges for developing drug and RNA co-delivery system, exosomes have been found to show very attractive prospects. This review aims to explore current technologies and challenges in the use of exosomes as drug and RNA co-delivery system with a focus on the emerging trends and issues associated with their further applications, which may contribute to the accelerated developments of exosome-based theraputics.

Filtration-based technologies for isolation, purification and analysis of extracellular vesicles

The involvement of extracellular vesicles (EVs) in cellular communication with multifactorial and multifaceted biological activity has generated significant interest, highlighting their potential diagnostic and therapeutic applications. EVs are found in nearly all biological fluids creating a broad spectrum of where potential disease markers can be found for liquid biopsy development and what subtypes can be used for treatment of diseases. Complexity of biological fluids has generated a variety of different approaches for EV isolation and identification that may in one way or another be most optimal for research studies or clinical use. Each approach has its own advantages and disadvantages, significance of which can be evaluated depending on the end goal of the study. One of the methods is based on filtration which has received attention in the past years due its versatility, low cost and other advantages. Introduction of different approaches for EV capture and analysis that are based on filtration gave rise to new subcategories of filtration techniques which are presented in this overview. Miniaturization and combination of filtration-based approaches with microfluidics is also highlighted due its future prospects in healthcare, especially point-of-need technologies.

Biodistribution of mesenchymal stromal cell-derived extracellular vesicles administered during acute lung injury

BACKGROUND

Mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) are a promising cell-free therapy for acute lung injury (ALI). To date, no studies have investigated their biodistribution in ALI or discerned the timing of administration for maximal lung targeting, which are crucial considerations for clinical translation. Our study aimed to characterize a mouse model of ALI and establish the distribution kinetics and optimal timing of MSC-EV delivery during lung injury.

METHODS

MSC-EVs were isolated by ultracentrifugation alone (U/C) or tangential flow filtration with ultracentrifugation (TFF-U/C) and characterized by nanoparticle tracking analysis and western blot. A lipopolysaccharide (LPS)-induced mouse model of ALI was established to study the inflammatory response over 72 h. ALI was assessed by histological lung injury score, bronchoalveolar lavage fluid cell count and inflammatory cytokines. For biodistribution studies, ALI mice were intravenously administered fluorescently labeled MSC-EVs to determine the optimal timing of administration and organ-specific biodistribution. Live in vivo and ex vivo fluorescence imaging was conducted at various timepoints post-EV injection.

RESULTS

EVs isolated by either ultracentrifugation alone or TFF-U/C displayed comparable size distribution (~ 50-350 nm) and EV marker expression (CD63/81). TFF-U/C generated a 5.4-fold higher particle concentration and 3.9-fold higher total protein when compared to ultracentrifugation alone. From the inflammatory time-course study, cell count and IL-1β peaked in bronchoalveolar lavage fluid at 24 h after ALI induction. MSC-EVs delivered at 24 h (as opposed to 0.5 h, 5 h or 10 h) after disease induction resulted in a 2.7-4.4-fold higher lung uptake of EVs. Biodistribution studies comparing organ-specific MSC-EV uptake showed progressive lung accumulation up to 48 h post-delivery (threefold higher than the spleen/liver), with a decline at 72 h. Importantly, lung EV fluorescence at 48 h in ALI mice was significantly elevated as compared to control mice. The lung tropism of MSC-EVs was further validated as therapeutically inert EVs derived from HEK293T cells accumulated mainly to the spleen and liver with a 5.5-fold lower distribution to the lungs as compared to MSC-EVs.

CONCLUSION

MSC-EVs exhibit maximal lung accumulation when administered during heightened inflammation at 24 h after ALI induction. This lung tropism suggests that MSC-EVs may serve as a practical rescue treatment for acute inflammatory respiratory conditions.

Small extracellular vesicles: a novel drug delivery system for neurodegenerative disorders

Neurodegenerative diseases (NDs) have a slow onset and are usually detected late during disease. NDs are often difficult to cure due to the presence of the blood-brain barrier (BBB), which makes it difficult to find effective treatments and drugs, causing great stress and financial burden to families and society. Currently, small extracellular vesicles (sEVs) are the most promising drug delivery systems (DDSs) for targeted delivery of molecules to specific sites in the brain as a therapeutic vehicle due to their low toxicity, low immunogenicity, high stability, high delivery efficiency, high biocompatibility and trans-BBB functionality. Here, we review the therapeutic application of sEVs in several NDs, including Alzheimer's disease, Parkinson's disease, and Huntington's disease, discuss the current barriers associated with sEVs and brain-targeted DDS, and suggest future research directions.

Large-scale heparin-based bind-and-elute chromatography identifies two biologically distinct populations of extracellular vesicles

Purifying extracellular vesicles (EVs) has been challenging because EVs are heterogeneous in cargo yet share similar sizes and densities. Most surface marker-based affinity separation methods are limited to research or diagnostic scales. We report that heparin chromatography can separate purified EVs into two distinct subpopulations as ascertained by MS/MS: a non-heparin-binding (NHB) fraction that contains classical EV markers such as tetraspanins and a heparin-binding (HB) fraction enriched in fibronectins and histones. Both fractions were similarly fusogenic but induced different transcriptional responses in endothelial cells. While EVs that were purified by conventional, non-affinity methods alone induced ERK1/2 phosphorylation and Ki67, the NHB fraction did not. This result suggests heparin chromatography as an additional novel fractionation step that is inherently scalable, does not lead to loss of material, and separates inflammatory and pyrogenic EVs from unreactive EVs, which will improve clinical applications.

Potency Assays for Mesenchymal Stromal Cell Secretome-Based Products for Tissue Regeneration

Adult stem cells maintaining tissue homeostasis and regeneration are tightly regulated by their specific microenvironments or stem cell niches. The dysfunction of niche components may alter the activity of stem cells and ultimately lead to intractable chronic or acute disorders. To overcome this dysfunction, niche-targeting regenerative medicine treatments such as gene, cell, and tissue therapy are actively investigated. Here, multipotent mesenchymal stromal cells (MSCs), and particularly their secretomes, are of high interest due to their potency to recover and reactivate damaged or lost stem cell niches. However, a workflow for the development of MSC secretome-based products is not fully covered by regulatory authorities, and and this issue significantly complicates their clinical translation and has possibly been expressed in a huge number of failed clinical trials. One of the most critical issues in this regard relates to the development of potency assays. In this review, guidelines for biologicals and cell therapies are considered to be applied for the development of potency assays for the MSC secretome-based products that aim for tissue regeneration. Specific attention is paid to their possible effects on stem cell niches and to a spermatogonial stem cell niche in particular.

Challenges and strategies: Scalable and efficient production of mesenchymal stem cells-derived exosomes for cell-free therapy

Exosomes are small membrane vesicles secreted by most cell types, and widely exist in cell supernatants and various body fluids. They can transmit numerous bioactive elements, such as proteins, nucleic acids, and lipids, to affect the gene expression and function of recipient cells. Mesenchymal stem cells (MSCs) have been confirmed to be a potentially promising therapy for tissue repair and regeneration. Accumulating studies demonstrated that the predominant regenerative paradigm of MSCs transplantation was the paracrine effect but not the differentiation effect. Exosomes secreted by MSCs also showed similar therapeutic effects as their parent cells and were considered to be used for cell-free regenerative medicine. However, the inefficient and limited production has hampered their development for clinical translation. In this review, we summarize potential methods to efficiently promote the yield of exosomes. We mainly focus on engineering the process of exosome biogenesis and secretion, altering the cell culture conditions, cell expansion through 3D dynamic culture and the isolation of exosomes. In addition, we also discuss the application of MSCs-derived exosomes as therapeutics in disease treatment.

Comparative study of size exclusion chromatography for isolation of small extracellular vesicle from cell-conditioned media, plasma, urine, and saliva

Introduction: Extracellular vesicles (EVs) are secreted from all types of cells and are involved in the trafficking of proteins, metabolites, and genetic material from cell to cell. According to their biogenesis and physical properties, EVs are often classified as small EVs (including exosomes) or large EVs, and large oncosomes. A variety of methods are used for isolated EVs; however, they have several limitations, including vesicle deformation, reduced particle yield, and co-isolate protein contaminants. Here we present an optimized fast and low-cost methodology to isolate small EVs (30–150 nm) from biological fluids comparing two SEC stationary phases, G200/120 and G200/140 columns.

Methods: The optimization parameters considered were a) the selection of the stationary phase, b) the eluate volume per fraction, and c) the selection of the enriched 30–150 nm EVs-fractions. The efficiency and separation profile of each UF/SEC fraction was evaluated by Nanoparticle tracking analysis (NTA), flow cytometry, total protein quantification, and Western blot.

Results: Both columns can isolate predominantly small EVs with low protein contaminants from plasma, urine, saliva, and HEK293-derived EV from collection medium. Column G200/ 40 offers a more homogeneous enrichment of vesicles between 30 and 150 nm than G200/120 [76.1 ± 4.4% with an average size of 85.9 ± 3.6 nm (Mode: 72.8 nm)] in the EV collection medium. The enrichment, estimated as the vesicle-to-protein ratio, was 1.3 × 1010 particles/mg protein for G200/40, obtaining a more significant EVs enrichment compared to G200/120. The optimized method delivers 0.8 ml of an EVs-enriched-outcome, taking only 30 min per sample. Using plasma, the enrichment of small EVs from the optimized method was 70.5 ± 0.18%, with an average size of 119.4 ± 6.9 nm (Mode: 120.3 nm), and the enrichment of the vesicle isolation was 4.8 × 1011 particles/mg protein. The average size of urine and saliva -EVs samples was 147.5 ± 3.4 and 111.9 ± 2.5 nm, respectively. All the small EVs isolated from the samples exhibit the characteristic cup-shaped morphology observed by Transmission electron microscopy (TEM).

Discussion: This study suggests that the combination of methods is a robust, fast, and improved strategy for isolating small EVs.

Biomimetic synthesis and optimization of extracellular vesicles for bone regeneration

Critical-size bone defect repair is in high demand but is difficult to treat. Modern therapies, such as autograft and cell-based treatments, face limitations, including potential immunological rejection and tumorigenesis. Therefore, extracellular vesicle (EV)-based strategies have been proposed as a novel approach for tissue regeneration owing to EVs' complex composition of lipids, proteins, and nucleic acids, as well as their low immunogenicity and congenital cell-targeting features. Despite these remarkable features of EVs, biomimetic synthesis and optimization of natural EVs can lead to enhanced bioactivity, increased cellular uptake, and specific cell targeting, aiming to achieve optimal therapeutic efficacy. To maximize their function, these nanoparticles can be integrated into bone graft biomaterials for superior bone regeneration. Herein, we summarize the role of naturally occurring EVs from distinct cell types in bone regeneration, the current strategies for optimizing biomimetic synthetic EVs in bone regeneration, and discuss the recent advances in applying bone graft biomaterials for the delivery of EVs to bone defect repair. We focused on distinct strategies for optimizing EVs with different functions and the most recent research on achieving time-controlled release of nanoparticles from EV-loaded biomaterials. Furthermore, we thoroughly discuss several current challenges and proposed solutions, aiming to provide insight into current progress, inspiration for future development directions, and incentives for clinical application in this field.

MSC-EVs alleviate osteoarthritis by regulating microenvironmental cells in the articular cavity and maintaining cartilage matrix homeostasis

Osteoarthritis (OA), a common cause of chronic articular cartilage degeneration, is the main cause of disability in older adults and severely affects quality of life. Multiple factors are involved in the pathogenesis of OA, resulting in imbalance in the homeostasis of the joint cavity microenvironment, which exacerbates the disease. Because of the deficiency of blood vessels and nerves in cartilage, existing therapies to promote cartilage healing are relatively ineffective. Mesenchymal stem cell (MSC)-related therapies have achieved positive outcomes for the treatment of OA, and these beneficial effects have been confirmed to be largely mediated by extracellular vesicles (EVs). MSC-derived EVs (MSC-EVs) have been demonstrated to participate in the regulation of chondrocyte function, to have anti-inflammatory and immunomodulatory effects, and to alleviate metabolic disorders of the extracellular matrix, thereby slowing the progression of OA. In addition, engineered MSC-EVs can enrich therapeutic molecules and optimize administration to enhance their therapeutic effects on OA. A thorough understanding of the endogenous properties of EVs and related engineering strategies could help researchers develop more precise control therapy for OA.

Extracellular Vesicles as New Players in Drug Delivery: A Focus on Red Blood Cells-Derived EVs

The article is divided into several sections, focusing on extracellular vesicles' (EVs) nature, features, commonly employed methodologies and strategies for their isolation/preparation, and their characterization/visualization. This work aims to give an overview of advances in EVs' extensive nanomedical-drug delivery applications. Furthermore, considerations for EVs translation to clinical application are summarized here, before focusing the review on a special kind of extracellular vesicles, the ones derived from red blood cells (RBCEVs). Generally, employing EVs as drug carriers means managing entities with advantageous properties over synthetic vehicles or nanoparticles. Besides the fact that certain EVs also reveal intrinsic therapeutic characteristics, in regenerative medicine, EVs nanosize, lipidomic and proteomic profiles enable them to pass biologic barriers and display cell/tissue tropisms; indeed, EVs engineering can further optimize their organ targeting. In the second part of the review, we focus our attention on RBCEVs. First, we describe the biogenesis and composition of those naturally produced by red blood cells (RBCs) under physiological and pathological conditions. Afterwards, we discuss the current procedures to isolate and/or produce RBCEVs in the lab and to load a specific cargo for therapeutic exploitation. Finally, we disclose the most recent applications of RBCEVs at the in vitro and preclinical research level and their potential industrial exploitation. In conclusion, RBCEVs can be, in the near future, a very promising and versatile platform for several clinical applications and pharmaceutical exploitations.