Exosomes isolated from two different cell lines using three different isolation techniques show variation in physical and molecular characteristics

The role of exosomes in liver cancer: comprehensive insights from biological function to therapeutic applications

In recent years, cancer, especially primary liver cancer (including hepatocellular carcinoma and intrahepatic cholangiocarcinoma), has posed a serious threat to human health. In the field of liver cancer, exosomes play an important role in liver cancer initiation, metastasis and interaction with the tumor microenvironment. Exosomes are a class of nanoscale extracellular vesicles (EVs)secreted by most cells and rich in bioactive molecules, including RNA, proteins and lipids, that mediate intercellular communication during physiological and pathological processes. This review reviews the multiple roles of exosomes in liver cancer, including the initiation, progression, and metastasis of liver cancer, as well as their effects on angiogenesis, epithelial-mesenchymal transformation (EMT), immune evasion, and drug resistance. Exosomes have great potential as biomarkers for liver cancer diagnosis and prognosis because they carry specific molecular markers that facilitate early detection and evaluation of treatment outcomes. In addition, exosomes, as a new type of drug delivery vector, have unique advantages in the targeted therapy of liver cancer and provide a new strategy for the treatment of liver cancer. The challenges and prospects of exosome-based immunotherapy in the treatment of liver cancer were also discussed. However, challenges such as the standardization of isolation techniques and the scalability of therapeutic applications remain significant hurdles.

Delivery of extracellular vesicles loaded with immune checkpoint inhibitors for immunotherapeutic management of glioma

Glioma is a common primary malignant brain tumor with low survival rate. Immunotherapy with immune checkpoints inhibitors (ICI) can be a choice for glioma management, and extracellular vesicles (EVs) are recognized as a potential drug delivery system for various disease management due to their enhanced barrier permeation ability and immunomodulatory effect. The aim of this study is to develop ICI-loaded EVs (ICI/EV) that have sufficient efficacy in managing glioma. Calcium phosphate particles (CaP) were used to stimulate the secretion of EVs from murine macrophage cells. CaP conditioning of cells showed an enhanced amount of EVs secretion and macrophage polarization toward a proinflammatory phenotype. The CaP-induced EVs were shown to polarize macrophages into proinflammatory phenotype in vitro, as correlated with the conditioning method. ICI/EVs were successfully prepared with high loading efficiency using the sonication method. The EVs can be distributed throughout the entire brain upon intranasal administration and facilitate ICIs distribution into glioma lesion. Combinatory treatment with ICI/EVs showed benefit in glioma-bearing mice by reducing their tumor volume and prolonging their survival. Cytotoxic T cell infiltration, polarization of tumor-associated macrophage, and lower tumor proliferation were observed in ICI/EVs-treated mice. The developed ICI/EVs showed promise in immunotherapeutic management of glioma.

Molecular profiling of blood plasma-derived extracellular vesicles derived from Duchenne muscular dystrophy patients through integration of FTIR spectroscopy and machine learning reveals disease signatures

PURPOSE

To identify and monitor the FTIR spectral signatures of plasma extracellular vesicles (EVs) from Duchenne Muscular Dystrophy (DMD) patients at different stages with Healthy controls using machine learning models.

MATERIALS AND METHODS

Whole blood samples were collected from the DMD (n = 30) and Healthy controls (n = 12). EVs were extracted by the Total Exosome Isolation (TEI) Method and resuspended in 1XPBS. We characterize the morphology, size, particle count, and surface markers (CD9, Alix, and Flotillin) by HR-TEM, NTA, and Western Blot analysis. The mid-IR spectra were recorded from (4000-400 cm-1) by Bruker ALPHA II FTIR spectrometer model, which was equipped with an attenuated total reflection (ATR) module. Machine learning algorithms like Principal Component Analysis (PCA) and Random Forest (RF) for dimensionality reduction and classifying the two study groups based on the FTIR spectra. The model performance was evaluated by a confusion matrix and the sensitivity, specificity, and Receiver Operating Characteristic Curve (ROC) was calculated respectively.

RESULTS

Alterations in Amide I & II (1700-1470 cm-1) and lipid (3000-2800 cm-1) regions in FTIR spectra of DMD compared with healthy controls. The PCA-RF model classified correctly the two study groups in the range of 4000-400 cm-1 with a sensitivity of 20 %, specificity of 87.50 %, accuracy of 71.43 %, precision of 33.33 %, and 5-fold cross-validation accuracy of 82 %. We analyzed the ten different spectral regions which showed statistically significant at P < 0.01 except the Ester Acyl Chain region.

CONCLUSION

Our proof-of-concept study demonstrated distinct infrared (IR) spectral signatures in plasma EVs derived from DMD. Consistent alterations in protein and lipid configurations were identified using a PCA-RF model, even with a small clinical dataset. This minimally invasive liquid biopsy method, combined with automated analysis, warrants further investigation for its potential in early diagnosis and monitoring of disease progression in DMD patients within clinical settings.

Immune-Cell-Derived Exosomes as a Potential Novel Tool to Investigate Immune Responsiveness in SCLC Patients: A Proof-of-Concept Study

Small cell lung cancer (SCLC) is a highly invasive and rapidly proliferating lung tumor subtype. Most patients respond well to a combination of platinum-based chemotherapy and PD-1/PDL-1 inhibitors. Unfortunately, not all patients benefit from this treatment regimen, and few alternative therapies are available. In this scenario, the identification of new biomarkers and differential therapeutic strategies to improve tumor response becomes urgent. Here, we investigated the role of exosomes (EXs) released from the peripheral blood mononuclear cells (PBMCs) of SCLC patients in mediating the functional crosstalk between the immune system and tumors in response to treatments. In this study, we showed that PBMC-EXs from SCLC patients with different responses to chemoimmunotherapy showed different levels of immune (STING and MAVS) and EMT (Snail and c-Myc) markers. We demonstrated that PBMC-EXs derived from best responder (BR) patients were able to induce a significant increase in apoptosis in SCLC cell lines in vitro compared to PBMC-EXs derived from non-responder (NR) SCLC patients. PBMC-EXs were able to affect cell viability and modulate apoptotic markers, DNA damage and the replication stress pathway, as well as the occurrence of EMT. Our work provides proof of concept that PBMC-EXs can be used as a tool to study the crosstalk between cancer cells and immune cells and that PBMC-EXs exhibit an in vitro ability to promote cancer cell death and reduce tumor aggressiveness.

Chemically Powered Nanomotors with Magnetically Responsive Function for Targeted Delivery of Exosomes

Janus structure plays a crucial role in achieving chemically driven nanomotors with exceptional motion performance. However, Janus-structured chemically driven nanomotors with magnetic responsiveness are commonly fabricated by sputtering metal films. In the study, a self-assembly technique is employed to asymmetrically modify the surfaces of magnetic silica (SiO2@Fe3O4) nanoparticles with platinum nanoparticles, resulting in the formation of this kind nanomotors. Compared to platinum film, platinum nanoparticles exhibit a larger surface area and a higher catalytic activity. Hence, the nanomotors demonstrate improved diffusion capabilities at a significantly lower concentration (0.05%) of hydrogen peroxide (H2O2). Meanwhile, exosomes have gained attention as a potential tool for the efficient delivery of biological therapeutic drugs due to their biocompatibility. However, the clinical applications of exosomes are limited by their restricted tropism. The previously obtained nanomotors are utilized to deliver exosomes, greatly enhancing its targetability. The drug doxorubicin (DOX) is subsequently encapsulated within exosomes, acting as a representative drug model. Under the conditions of H2O2 concentration at the tumor site, the exosomes exhibited a significantly enhanced rate of entry into the breast cancer cells. The utilization of the nanomotors for exosomes presents a novel approach in the development of hybrid chemically and magnetically responsive nanomotors.

Exploring novel circulating biomarkers for liver cancer through extracellular vesicle characterization with infrared spectroscopy and plasmonics

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common form of liver cancer, with cirrhosis being a major risk factor. Traditional blood markers like alpha-fetoprotein (AFP) demonstrate limited efficacy in distinguishing between HCC and cirrhosis, underscoring the need for more effective diagnostic methodologies. In this context, extracellular vesicles (EVs) have emerged as promising candidates; however, their practical diagnostic application is restricted by the current lack of label-free methods to accurately profile their molecular content. To address this gap, our study explores the potential of mid-infrared (mid-IR) spectroscopy, both alone and in combination with plasmonic nanostructures, to detect and characterize circulating EVs.

RESULTS

EVs were extracted from HCC and cirrhotic patients. Mid-IR spectroscopy in the Attenuated Total Reflection (ATR) mode was utilized to identify potential signatures for patient classification, highlighting significant changes in the Amide I-II region (1475-1700 cm-1). This signature demonstrated diagnostic performance comparable to AFP and surpassed it when the two markers were combined. Further investigations utilized a plasmonic metasurface suitable for ultrasensitive spectroscopy within this spectral range. This device consists of two sets of parallel rod-shaped gold nanoantennas (NAs); the longer NAs produced an intense near-field amplification in the Amide I-II bands, while the shorter NAs were utilized to provide a sharp reflectivity edge at 1800-2200 cm-1 for EV mass-sensing. A clinically relevant subpopulation of EVs was targeted by conjugating NAs with an antibody specific to Epithelial Cell Adhesion Molecule (EpCAM). This methodology enabled the detection of variations in the quantity of EpCAM-presenting EVs and revealed changes in the Amide I-II lineshape.

SIGNIFICANCE

The presented results can positively impact the development of novel laboratory methods for the label-free characterization of EVs, based on the combination between mid-IR spectroscopy and plasmonics. Additionally, data obtained by using HCC and cirrhotic subjects as a model system, suggest that this approach could be adapted for monitoring these conditions.

Self-Assembled DNA Microflowers for Platelet-Derived Extracellular Vesicle Isolation and Infected Wound Healing

Platelet-derived extracellular vesicles (PEVs) showing great potential in wound healing have attracted increasing attention recently. Nondestructive isolation and effective utilization strategies are highly conducive for PEVs developing into recognized therapeutic entities. Here, we present an efficient strategy for PEV isolation and bacterial infected wound healing based on self-assembled DNA microflowers. First, DNA microflowers are prepared using rolling circle amplification. Then, the hydrophobic interaction between cholesteryl modified on DNA microflowers and the phospholipid bilayer membrane of PEVs leads to the formation of a network structure with improved mechanical strength and the separation of PEVs from biological samples. Finally, controlled release of PEVs is achieved through bacterial-induced hydrogel degradation. In vitro experiments demonstrate the obtained DNA hydrogel with good cytocompatibility and therapeutic potential. Taken together, the DNA microflower-based hydrogels with bioadhesive, self-healing, tunable mechanical properties and bacteria-responsive behavior offer substantial potential for EV isolation and wound healing.

Recent progress in engineered extracellular vesicles and their biomedical applications

AIMS

To present the recent update on the isolation, engineering techniques for extracellular vesicles, limitations associated with different isolation techniques, different biomedical applications, and challenges of engineered extracellular vesicles for the benefit of researchers from academic, industry, etc. MATERIALS AND METHODS: Peer-reviewed articles from most recognized journals were collected, and presented information was analyzed to discuss collection, chemical, electroporation, cellular, and membrane surface engineering to design extracellular vesicles for various therapeutic applications. In addition, we present the applications and limitations of techniques for the collection of extracellular vesicles.

KEY FINDINGS

There is a need for isolation techniques with the gold standard. However, advanced extracellular vesicle isolation techniques showed improved recovery, and purity of extracellular vesicles. Tumor therapy is a major part of the therapy section that illustrates the role of engineered extracellular vesicles in synergetic therapy such as phototherapy, theragnostic, and delivery of genetic materials. In addition, extracellular vesicles have shown their potential in the treatment of retinal disorders, neurodegenerative disease, tuberculosis, osteoporosis, inflammatory bowel disease, vaccine production, and wound healing.

SIGNIFICANCE

Engineered extracellular vesicles can deliver cargo to the specific cells, elicit an immune response and could be used for the development of the vaccines in the future. However, the progress is at the initial stage. Overall, this review will provide a comprehensive understanding and could serve as a reference for researchers in the clinical translation of engineered extracellular vesicles in different biomedical fields.

Characterization of effective, simple, and low-cost precipitation methods for depleting abundant plasma proteins to enhance the depth and breadth of plasma proteomics

Plasma is an abundant source of proteins and potential biomarkers to aid in the detection, diagnosis, and prognosis of human diseases. These proteins are often present at low levels in the blood and difficult to identify and measure due to the large dynamic range of proteins. The goal of this work was to characterize and compare various protein precipitation methods related to how they affect the depth and breadth of plasma proteomic studies. Abundant protein precipitation with perchloric acid (PerCA) can increase protein identifications and depth of plasma proteomic studies. Three acid- and four solvent-based precipitation methods were evaluated. All methods tested provided excellent plasma proteomic coverage (>600 identified protein groups) and detected protein in the low pg/mL range. Functional enrichment analysis revealed subtle differences within and larger changes between the precipitant groups. Methanol-based precipitation outperformed the other methods based on identifications and reproducibility. The methods' performance was verified using eight lung cancer patient samples, where >700 protein groups were measured and proteins with an estimated plasma concentration of ∼10 pg/mL were detected. Various protein precipitation agents are amenable to extending the depth and breadth of plasma proteomes. These data can guide investigators to implement inexpensive, high-throughput methods for their plasma proteomic workflows.

Sustained exposure to high glucose induces differential expression of cellular senescence markers in murine macrophages but impairs immunosurveillance response to senescent cells secretome

The influence of chronic diseases on various facets of macrophage cellular senescence is poorly understood. This study evaluated the impact of chronic hyperglycemia on the induction of cellular senescence and subsequent immunosurveillance functions in RAW264.7 macrophages. Macrophages were cultured under normal glucose (NG; 5 mM), high glucose (HG; 20 mM), and very high glucose (VHG; 40 mM) conditions and assessed for markers of cellular senescence. Hyperglycemia induced strong upregulation of SA-β-gal activity, and loss of PCNA and Lamin B1 gene expression while markers of cell cycle arrest generally decreased. Non-significant changes in SASP-related proteins were observed while ROS levels slightly decreased and mitochondrial membrane potential increased. Protein concentration on the exosome membrane surface and their stability appeared to increase under hyperglycemic conditions. However, when macrophages were exposed to the secretory media (SM) of senescent preadipocytes, a dramatic increase in the levels of all inflammatory proteins was recorded especially in the VHG group that was also accompanied by upregulation of NF-κB and NLRP3 gene expression. SM treatment to hyperglycemic macrophages activated the TLR-2/Myd88 pathway but decreased the expression of scavenger receptors RAGE, CD36, and Olr-1 while CD44 and CXCL16 expression increased. On exposure to LPS, a strong upregulation in NO, ROS, and inflammatory cytokines was observed. Together, these results suggest that primary markers of cellular senescence are aberrantly expressed under chronic hyperglycemic conditions in macrophages with no significant SASP activation. Nonetheless, hyperglycemia strongly deregulates macrophage functions leading to impaired immunosurveillance of senescent cells and aggravation of inflamm-aging. This work provides novel insights into how hyperglycemia-induced dysfunctions can impact the potency of macrophages to manage senescent cell burden in aging tissues.

Ultrasound-assisted encapsulating folic acid-based carbon quantum dots within breast cancer cell-derived exosomes as a co-receptors-mediated anticancer nanocarrier for enhanced breast cancer therapy

The nonspecific nature of cancer drug delivery often results in substantial toxic side effects during treatments for breast cancer. To mitigate these negative outcomes, our approach involves loading methotrexate (MTX) within carbon quantum dots (CQDs) synthesized from folic acid, which are then enveloped in exosomal membranes obtained from breast cancer cells (Ex@MTX-CQDs). Analysis utilizing nanoparticle tracking techniques has demonstrated that these Ex@MTX-CQDs maintain the physical and biochemical properties of their exosomal precursors. The release profile of MTX indicated a restricted release percentage (less than 10%) under normal physiological conditions, which is contrasted by a more consistent release rate (approximately 65%) when emulating the conditions found within tumor tissues. The toxicological assessments have confirmed that the presence of exosomes combined with leftover folic acid significantly improves the delivery efficacy of MTX directly to the cancerous cells through the binding to folate and heparan sulfate proteoglycan receptors. This process results in increased disruption of the mitochondrial membrane potential and subsequently triggers apoptosis, ultimately leading to the destruction of cancerous cells. Our research could potentially contribute to the further innovation and application of nanocarriers derived from biological sources for the targeted treatment of breast cancer.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes as Nanomedicine for Peripheral Nerve Injury

Peripheral nerve injury (PNI) is a complex and protracted process, and existing therapeutic approaches struggle to achieve effective nerve regeneration. Recent studies have shown that mesenchymal stem cells (MSCs) may be a pivotal choice for treating peripheral nerve injury. MSCs possess robust paracrine capabilities, and exosomes, as the primary secretome of MSCs, are considered crucial regulatory mediators involved in peripheral nerve regeneration. Exosomes, as nanocarriers, can transport various endogenous or exogenous bioactive substances to recipient cells, thereby promoting vascular and axonal regeneration while suppressing inflammation and pain. In this review, we summarize the mechanistic roles of exosomes derived from MSCs in peripheral nerve regeneration, discuss the engineering strategies for MSC-derived exosomes to improve therapeutic potential, and explore the combined effects of MSC-derived exosomes with biomaterials (nerve conduits, hydrogels) in peripheral nerve regeneration.

Comparison of the efficiency of ultrafiltration, precipitation, and ultracentrifugation methods for exosome isolation

Extracellular vesicles (EVs) are enclosed by a lipid-bilayer membrane and secreted by all types of cells. They are classified into three groups: apoptotic bodies, microvesicles, and exosomes. Exosomes play a number of important roles in the intercellular communication and crosstalk between tissues in the body. In this study, we use three common methods based on different principles for exosome isolation, namely ultrafiltration, precipitation, and ultracentrifugation. We use field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS) analyses for characterization of exosomes. The functionality and effect of isolated exosomes on the viability of hypoxic cells was investigated by alamarBlue and Flow-cytometry. The results of the FESEM study show that the ultrafiltration method isolates vesicles with higher variability of shapes and sizes when compared to the precipitation and ultracentrifugation methods. DLS results show that mean size of exosomes isolated by ultrafiltration, precipitation, and ultracentrifugation methods are 122, 89, and 60 nm respectively. AlamarBlue analysis show that isolated exosomes increase the viability of damaged cells by 11%, 15%, and 22%, respectively. Flow-cytometry analysis of damaged cells also show that these vesicles increase the content of live cells by 9%, 15%, and 20%, respectively. This study shows that exosomes isolated by the ultracentrifugation method are characterized by smaller size and narrow size distribution. Furthermore, more homogenous particles isolated by this method show increased efficiency of the protection of hypoxic cells in comparison with the exosomes isolated by the two other methods.

Adipose-Derived Stem Cell Exosomes Facilitate Diabetic Wound Healing: Mechanisms and Potential Applications

Wound healing in diabetic patients is frequently hampered. Adipose-derived stem cell exosomes (ADSC-eoxs), serving as a crucial mode of intercellular communication, exhibit promising therapeutic roles in facilitating wound healing. This review aims to comprehensively outline the molecular mechanisms through which ADSC-eoxs enhance diabetic wound healing. We emphasize the biologically active molecules released by these exosomes and their involvement in signaling pathways associated with inflammation modulation, cellular proliferation, vascular neogenesis, and other pertinent processes. Additionally, the clinical application prospects of the reported ADSC-eoxs are also deliberated. A thorough understanding of these molecular mechanisms and potential applications is anticipated to furnish a theoretical groundwork for combating diabetic wound healing.

Amniotic fluid-derived stem cells: potential factories of natural and mimetic strategies for congenital malformations

Background

Mesenchymal stem cells (MSCs) from gestational tissues represent promising strategies for in utero treatment of congenital malformations, but plasticity and required high-risk surgical procedures limit their use. Here we propose natural exosomes (EXOs) isolated from amniotic fluid-MSCs (AF-MSCs), and their mimetic counterparts (MIMs), as valid, stable, and minimally invasive therapeutic alternatives.

Methods

MIMs were generated from AF-MSCs by combining sequential filtration steps through filter membranes with different porosity and size exclusion chromatography columns. Physiochemical and molecular characterization was performed to compare them to EXOs released from the same number of cells. The possibility to exploit both formulations as mRNA-therapeutics was explored by evaluating cell uptake (using two different cell types, fibroblasts, and macrophages) and mRNA functionality overtime in an in vitro experimental setting as well as in an ex vivo, whole embryo culture using pregnant C57BL6 dams.

Results

Molecular and physiochemical characterization showed no differences between EXOs and MIMs, with MIMs determining a 3-fold greater yield. MIMs delivered a more intense and prolonged expression of mRNA encoding for green fluorescent protein (GFP) in macrophages and fibroblasts. An ex-vivo whole embryo culture demonstrated that MIMs mainly accumulate at the level of the yolk sac, while EXOs reach the embryo.

Conclusions

The present data confirms the potential application of EXOs for the prenatal repair of neural tube defects and proposes MIMs as prospective vehicles to prevent congenital malformations caused by in utero exposure to drugs.

Human plasma derived exosomes: Impact of active and passive drug loading approaches on drug delivery

The aim of the current study was to explore the potential of human plasma-derived exosomes as versatile carriers for drug delivery by employing various active and passive loading methods. Exosomes were isolated from human plasma using differential centrifugation and ultrafiltration method. Drug loading was achieved by employing sonication and freeze thaw methods, facilitating effective drug encapsulation within exosomes for delivery. Each approach was examined for its effectiveness, loading efficiency and ability to preserve membrane stability. Methotrexate (MTX), a weak acid model drug was loaded at a concentration of 2.2 µM to exosomes underwent characterization using various techniques such as particle size analysis, transmission electron microscopy and drug loading capacity. Human plasma derived exosomes showed a mean size of 162.15 ± 28.21 nm and zeta potential of -30.6 ± 0.71 mV. These exosomes were successfully loaded with MTX demonstrated a better drug encapsulation of 64.538 ± 1.54 % by freeze thaw method in comparison 55.515 ± 1.907 % by sonication. In-vitro drug release displayed 60 % loaded drug released within 72 h by freeze thaw method that was significantly different from that by sonication method i.e., 99 % within 72 h (p value 0.0045). Moreover, cell viability of exosomes loaded by freeze thaw method was significantly higher than that by sonication method (p value 0.0091) suggested that there was membrane disruption by sonication method. In conclusion, this study offers valuable insights into the potential of human plasma-derived exosomes loaded by freeze thaw method suggest as a promising carrier for improved drug loading and maintenance of exosomal membrane integrity.

Proteomic profiling of mesenchymal stem cell-derived extracellular vesicles: Impact of isolation methods on protein cargo

Extracellular vesicles (EVs) are nanosized vesicles with a lipid bilayer that are secreted by cells and play a critical role in cell-to-cell communication. Despite the promising reports regarding their diagnostic and therapeutic potential, the utilization of EVs in the clinical setting is limited due to insufficient information about their cargo and a lack of standardization in isolation and analysis methods. Considering protein cargos in EVs as key contributors to their therapeutic potency, we conducted a tandem mass tag (TMT) quantitative proteomics analysis of three subpopulations of mesenchymal stem cell (MSC)-derived EVs obtained through three different isolation techniques: ultracentrifugation (UC), high-speed centrifugation (HS), and ultracentrifugation on sucrose cushion (SU). Subsequently, we checked EV marker expression, size distribution, and morphological characterization, followed by bioinformatic analysis. The bioinformatic analysis of the proteome results revealed that these subpopulations exhibit distinct molecular and functional characteristics. The choice of isolation method impacts the proteome of isolated EVs by isolating different subpopulations of EVs. Specifically, EVs isolated through the high-speed centrifugation (HS) method exhibited a higher abundance of ribosomal and mitochondrial proteins. Functional apoptosis assays comparing isolated mitochondria with EVs isolated through different methods revealed that HS-EVs, but not other EVs, induced early apoptosis in cancer cells. On the other hand, EVs isolated using the sucrose cushion (SU) and ultracentrifugation (UC) methods demonstrated a higher abundance of proteins primarily involved in the immune response, cell-cell interactions and extracellular matrix interactions. Our analyses unveil notable disparities in proteins and associated biological functions among EV subpopulations, underscoring the importance of meticulously selecting isolation methods and resultant EV subpopulations based on the intended application.

Extracellular vesicles in nanomedicine and regenerative medicine: A review over the last decade

Small extracellular vesicles (sEVs) are known to be secreted by a vast majority of cells. These sEVs, specifically exosomes, induce specific cell-to-cell interactions and can activate signaling pathways in recipient cells through fusion or interaction. These nanovesicles possess several desirable properties, making them ideal for regenerative medicine and nanomedicine applications. These properties include exceptional stability, biocompatibility, wide biodistribution, and minimal immunogenicity. However, the practical utilization of sEVs, particularly in clinical settings and at a large scale, is hindered by the expensive procedures required for their isolation, limited circulation lifetime, and suboptimal targeting capacity. Despite these challenges, sEVs have demonstrated a remarkable ability to accommodate various cargoes and have found extensive applications in the biomedical sciences. To overcome the limitations of sEVs and broaden their potential applications, researchers should strive to deepen their understanding of current isolation, loading, and characterization techniques. Additionally, acquiring fundamental knowledge about sEVs origins and employing state-of-the-art methodologies in nanomedicine and regenerative medicine can expand the sEVs research scope. This review provides a comprehensive overview of state-of-the-art exosome-based strategies in diverse nanomedicine domains, encompassing cancer therapy, immunotherapy, and biomarker applications. Furthermore, we emphasize the immense potential of exosomes in regenerative medicine.

Role of Exosomes in Cancer and Aptamer-Modified Exosomes as a Promising Platform for Cancer Targeted Therapy

Exosomes are increasingly recognized as important mediators of intercellular communication in cancer biology. Exosomes can be derived from cancer cells as well as cellular components in tumor microenvironment. After secretion, the exosomes carrying a wide range of bioactive cargos can be ingested by local or distant recipient cells. The released cargos act through a variety of mechanisms to elicit multiple biological effects and impact most if not all hallmarks of cancer. Moreover, owing to their excellent biocompatibility and capability of being easily engineered or modified, exosomes are currently exploited as a promising platform for cancer targeted therapy. In this review, we first summarize the current knowledge of roles of exosomes in risk and etiology, initiation and progression of cancer, as well as their underlying molecular mechanisms. The aptamer-modified exosome as a promising platform for cancer targeted therapy is then briefly introduced. We also discuss the future directions for emerging roles of exosome in tumor biology and perspective of aptamer-modified exosomes in cancer therapy.

Canine Mesenchymal Stromal Cell Exosomes: State-of-the-Art Characterization, Functional Analysis and Applications in Various Diseases

Canine mesenchymal stromal cells (MSCs) possess the capacity to differentiate into a variety of cell types and secrete a wide range of bioactive molecules in the form of soluble and membrane-bound exosomes. Extracellular vesicles/exosomes are nano-sized vesicles that carry proteins, lipids, and nucleic acids and can modulate recipient cell response in various ways. The process of exosome formation is a physiological interaction between cells. With a significant increase in basic research over the last two decades, there has been a tremendous expansion in research in MSC exosomes and their potential applications in canine disease models. The characterization of exosomes has demonstrated considerable variations in terms of source, culture conditions of MSCs, and the inclusion of fetal bovine serum or platelet lysate in the cell cultures. Furthermore, the amalgamation of exosomes with various nano-materials has become a novel approach to the fabrication of nano-exosomes. The fabrication of exosomes necessitates the elimination of extrinsic proteins, thus enhancing their potential therapeutic uses in a variety of disease models, including spinal cord injury, osteoarthritis, and inflammatory bowel disease. This review summarizes current knowledge on the characteristics, biological functions, and clinical relevance of canine MSC exosomes and their potential use in human and canine research. As discussed, exosomes have the ability to control lethal vertebrate diseases by administration directly at the injury site or through specific drug delivery mechanisms.

Exosome subpopulations: The isolation and the functions in diseases

Exosomes are nanoscale extracellular vesicles secreted by cells. Exosomes mediate intercellular communication by releasing their bioactive contents (e.g., DNAs, RNAs, lipids, proteins, and metabolites). The components of exosomes are regulated by the producing cells of exosomes. Due to their diverse origins, exosomes are highly heterogeneous in size, content, and function. Depending on these characteristics, exosomes can be divided into multiple subpopulations which have different functions. Efficient enrichment of specific subpopulations of exosomes helps to investigate their biological functions. Accordingly, numerous techniques have been developed to isolate specific subpopulations of exosomes. This review systematically introduces emerging new technologies for the isolation of different exosome subpopulations and summarizes the critical role of specific exosome subpopulations in diseases, especially in tumor occurrence and progression.

Advancements in Mid-Infrared spectroscopy of extracellular vesicles

Extracellular vesicles (EVs) are lipid vesicles secreted by all cells into the extracellular space and act as nanosized biological messengers among cells. They carry a specific molecular cargo, composed of lipids, proteins, nucleic acids, and carbohydrates, which reflects the state of their parent cells. Due to their remarkable structural and compositional heterogeneity, characterizing EVs, particularly from a biochemical perspective, presents complex challenges. In this context, mid-infrared (IR) spectroscopy is emerging as a valuable tool, providing researchers with a comprehensive and label-free spectral fingerprint of EVs in terms of their specific molecular content. This review aims to provide an up-to-date critical overview of the major advancements in mid-IR spectroscopy of extracellular vesicles, encompassing both fundamental and applied research achievements. We also systematically emphasize the new possibilities offered by the integration of emerging cutting-edge IR technologies, such as tip-enhanced and surface-enhanced spectroscopy approaches, along with the growing use of machine learning for data analysis and spectral interpretation. Additionally, to assist researchers in navigating this intricate subject, our manuscript includes a wide and detailed collection of the spectral peaks that have been assigned to EV molecular constituents up to now in the literature.

Isolation of plant-derived exosome-like nanoparticles (PDENs) from Solanum nigrum L. berries and Their Effect on interleukin-6 expression as a potential anti-inflammatory agent

Inflammation is a temporary response of the immune system that can be treated using common anti-inflammatory drugs. However, prolonged use of these drugs increases the risk of adverse side effects. Accordingly, there is an increasing need for alternative treatments for inflammation with fewer side effects. Exosomes are extracellular vesicles secreted by most eukaryotic cells and have been studied as a candidate for cell-free therapy for inflammatory diseases due to their immunomodulatory and anti-inflammatory properties. In recent years, the focus of exosome research has shifted from animal cell-derived exosomes to plant-derived exosome-like nanoparticles (PDENs). Plant-derived exosome-like nanoparticles (PDENs) are easier to obtain, have minimal safety concerns, and can be produced in higher quantities and lower cost than exosomes derived from animal cells. In this study, the isolation and analysis of the anti-inflammatory potential of PDENs from black nightshade berries (Solanum nigrum L.) were carried out. The results of isolation and characterization showed that PDENs had a spherical morphology, measuring around 107 nm with zeta potential of -0.6 mV, and had a protein concentration of 275.38 μg/mL. PDENs were also shown to be internalized by RAW264.7 macrophage cell line after 2 hours of incubation and had no cytotoxicity effect up to the concentration of 2.5 μg/mL. Furthermore, exposure to several doses of PDENs to the LPS-stimulated RAW264.7 cell significantly decreased the expression of pro-inflammatory cytokine gene IL-6, as well as the expression of IL-6 protein up to 97,28%. GC-MS analysis showed the presence of neral, a monoterpene compound with known anti-inflammatory properties, which may contribute to the anti-inflammatory activity of PDENs isolated from Solanum nigrum L. berries. Taken together, the present study was the first to isolate and characterize PDENs from Solanum nigrum L. berries. The results of this study also demonstrated the anti-inflammatory activity of PDEN by suppressing the production of IL-6 in LPS-stimulated RAW264.7 cells.

Extracellular vesicles and their engineering strategies, delivery systems, and biomedical applications

Extracellular vesicles are nanoscale vesicles that can be secreted by all cell types, are intracellular in origin and have the same composition as their parent cells, play a key role in intercellular communication in organismal health and disease, and are now often used as biomarkers of disease and therapeutic agents in biomedical research. When injected locally or systemically, they have the ability to provide a variety of therapeutic effects, for example, regeneration of skin damage or restoration of cardiac function. However, direct injection of extracellular vesicles may result in their rapid clearance from the injection site.In order to maintain the biological activity of extracellular vesicles and to control the release of effective concentrations for better therapeutic efficacy during long-term disease treatment, the design of an optimized drug delivery system is necessary and different systems for the continuous delivery of extracellular vesicles have been developed. This paper first provides an overview of the biogenesis, composition and physiological function of extracellular vesicles, followed by a review of different strategies for extracellular vesicle isolation and methods for engineering extracellular vesicles. In addition, this paper reviews the latest extracellular vesicle delivery platforms such as micro-nanoparticles, injectable hydrogels, microneedles and scaffold patches. At the same time, the research progress and key cases of extracellular vesicle delivery systems in the field of biomedical therapeutics are described. Finally, the challenges and future trends of extracellular vesicle delivery are discussed.

A review on the use of extracellular vesicles for the delivery of drugs and biological therapeutics

INTRODUCTION

Exosomes, a type of extracellular vesicles, are effective tools for delivering small-molecule drugs and biological therapeutics into cells and tissues. Surface modifications with targeting ligands ensure precise delivery to specific cells, minimizing accumulation in healthy organs and reducing the side effects. This is a rapidly growing area in drug delivery research and this review aims to comprehensively discuss the recent advances in the field.

AREA COVERED

Recent studies have presented compelling evidence supporting the application of exosomes as efficient delivery vehicles that escape endosome trapping, achieving effective in vivo delivery in animal models. This review provides a systemic discussion on the exosome-based delivery technology, with topics covering exosome purification, surface modification, and targeted delivery of various cargos ranging from siRNAs, miRNAs, and proteins, to small molecule drugs.

EXPERT OPINION

Exosome-based gene and drug delivery has low toxicity and low immunogenicity. Surface modifications of the exosomes can effectively avoid endosome trapping and increase delivery efficiency. This exciting technology can be applied to improve the treatments for a wide variety of diseases.

Exosomes: Friends or Foes in Microbial Infections?

The use of new approaches is necessary to address the global issue of infections caused by drug-resistant pathogens. Antimicrobial photodynamic therapy (aPDT) is a promising approach that reduces the emergence of drug resistance, and no resistance has been reported thus far. APDT involves using a photosensitizer (PS), a light source, and oxygen. The mechanism of aPDT is that a specific wavelength of light is directed at the PS in the presence of oxygen, which activates the PS and generates reactive oxygen species (ROS), consequently causing damage to microbial cells. However, due to the PS's poor stability, low solubility in water, and limited bioavailability, it is necessary to employ drug delivery platforms to enhance the effectiveness of PS in photodynamic therapy (PDT). Exosomes are considered a desirable carrier for PS due to their specific characteristics, such as low immunogenicity, innate stability, and high ability to penetrate cells, making them a promising platform for drug delivery. Additionally, exosomes also possess antimicrobial properties, although in some cases, they may enhance microbial pathogenicity. As there are limited studies on the use of exosomes for drug delivery in microbial infections, this review aims to present significant points that can provide accurate insights.

Application of exosomes as nanocarriers in cancer therapy

Cancer remains the most common lethal disease in the world. Although the treatment choices for cancer are still limited, significant progress has been made over the past few years. By improving targeted drug therapy, drug delivery systems promoted the therapeutic effects of anti-cancer medications. Exosome is a kind of natural nanoscale delivery system with natural substance transport properties, good biocompatibility, and high tumor targeting, which shows great potential in drug carriers, thereby providing novel strategies for cancer therapy. In this review, we present the formation, distribution, and characteristics of exosomes. Besides, extraction and isolation techniques are discussed. We focus on the recent progress and application of exosomes in cancer therapy in four aspects: exosome-mediated gene therapy, chemotherapy, photothermal therapy, and combination therapy. The current challenges and future developments of exosome-mediated cancer therapy are also discussed. Finally, the latest advances in the application of exosomes as drug delivery carriers in cancer therapy are summarized, which provide practical value and guidance for the development of cancer therapy.

Recent engineering advances of EVs for compounds, nucleic acids, and TCM delivery

Extracellular vesicles (EVs) are phospholipid bilayer nano-vesicles that were originally identified to deliver signals for intercellular communications. Based on the dynamic contents including proteins, nucleic acids and metabolites, EVs have been developed into diagnostic and therapeutic fields including cardiovascular diseases, neurological disorders and infectious diseases. A growing number of investigations revealed that EVs are also powerful carriers of loaded compounds and nucleic acids as enhanced treatments. Herein, we summarized the recent engineering advances related to three major issues when applying EVs in drug delivery systems: EVs isolation, drug loading strategies and targeting delivery approaches. Moreover, current applications of traditional Chinese medicine (TCM), in composition or compound form, are searched and listed as unique combinations with EVs. Further, we discuss emerging challenges and consider future directions of drug-loading EVs in therapeutic opportunities. This review discusses pros and cons of collecting, drug loading and delivery strategies of EVs as delivery systems, and highlights the promising combination with traditional Chinese medicine to help us advance its clinical application.

Exosomes from metastatic colon cancer cells drive the proliferation and migration of primary colon cancer through increased expression of cancer stem cell markers CD133 and DCLK1

The exchange of biological material between the neighbouring cells is essential for homeostasis. In pathological conditions, such as cancer, the major challenge in cancer treatment is the abnormal expression of crucial proteins and miRNA exchanged between the cancer cells through extracellular vesicles called exosomes. Clinically, it has been noticed that the primary tumour and the distal metastases are interconnected and co-dependent. The exosomes are key factors responsible for preparing the pre-metastatic niche and communicating between the tumour and the distal metastatic site. Cancer stem cells (CSCs) are a subpopulation of cancer cells with self-renewal characteristics and are shown to be responsible for metastasis. This study aims to understand the effect of metastatic cell line-derived exosomes and their regulation of CSC marker expressions on primary colon cancer cell lines. We have identified that treatment of primary colon cancer cell lines with metastatic colon cancer cell-derived exosomes has significantly increased the proliferation, colony formation, cell migration, and invasion. In addition, there was a significant increase in the number and size of spheroids following the exosomes treatment. We found that this metastatic phenotype is due to the increased expression of CD133 and DCLK1 in primary colon cancer cells.

Evaluation of exosomes encapsulated recombinant Interleukin-29 for its in vitro anticancer studies

Exosomes have recently been considered ideal biotherapeutic nanocarriers that broaden the frontiers of current drug delivery systems to overcome the shortcomings associated with cytokine-based immunotherapy. Using this approach, the current study aimed to assess anti-proliferative activity of purified IL-29 and exosomes encapsulated IL-29. The IL-29+pET-28a construct was transformed into Rosetta 2(DE3) cells which was used for the large-scale production of IL-29. Exosomes isolated from H1HeLa, and SF-767 cells using Total Exosome Isolation reagent were loaded with IL-29 via sonication. Isolation of exosomes was validated using their core protein signature by western blotting and specific miRNA profiles by RT-PCR. The drug loading efficiency of exosomes derived from H1HeLa cells was higher than that of SF-767-derived exosomes. The drug release kinetics of IL-29 encapsulated exosomes exhibited stable release of the recombinant drug. Around 50% of all cancer cell lines survived when IL-29 was administered at a concentration of 20 µg/mL. A survival rate of less than 10% was observed when cells were treated with 20 µg/mL IL-29 loaded exosomes. It was concluded that IL-29 loaded exosomes had a more significant cytotoxic effect against cancer cells, which might be attributed to sustained drug release, improved half-life, superior targeting efficacy, capacity to harness endogenous intracellular trafficking pathways, and heightened biocompatibility of exosomes.

Strategies for targeted gene delivery using lipid nanoparticles and cell-derived nanovesicles

Gene therapy is a promising approach for the treatment of many diseases. However, the effective delivery of the cargo without degradation in vivo is one of the major hurdles. With the advent of lipid nanoparticles (LNPs) and cell-derived nanovesicles (CDNs), gene delivery holds a very promising future. The targeting of these nanosystems is a prerequisite for effective transfection with minimal side-effects. In this review, we highlight the emerging strategies utilized for the effective targeting of LNPs and CDNs, and we summarize the preparation methodologies for LNPs and CDNs. We have also highlighted the non-ligand targeting of LNPs toward certain organs based on their composition. It is highly expected that continuing the developments in the targeting approaches of LNPs and CDNs for the delivery system will further promote them in clinical translation.

Physiological and pathological consequences of exosomes at the blood-brain-barrier interface

Blood-brain barrier (BBB) interface with multicellular structure controls strictly the entry of varied circulating macromolecules from the blood-facing surface into the brain parenchyma. Under several pathological conditions within the central nervous system, the integrity of the BBB interface is disrupted due to the abnormal crosstalk between the cellular constituents and the recruitment of inflammatory cells. Exosomes (Exos) are nano-sized extracellular vesicles with diverse therapeutic outcomes. These particles transfer a plethora of signaling molecules with the potential to modulate target cell behavior in a paracrine manner. Here, in the current review article, the therapeutic properties of Exos and their potential in the alleviation of compromised BBB structure were discussed. Video Abstract.

Label-Free Identification of Exosomes using Raman Spectroscopy and Machine Learning

Exosomes, nano-sized extracellular vesicles (EVs) secreted from cells, carry various cargo molecules reflecting their cells of origin. As EV content, structure, and size are highly heterogeneous, their classification via cargo molecules by determining their origin is challenging. Here, a method is presented combining surface-enhanced Raman spectroscopy (SERS) with machine learning algorithms to employ the classification of EVs derived from five different cell lines to reveal their cellular origins. Using an artificial neural network algorithm, it is shown that the label-free Raman spectroscopy method's prediction ratio correlates with the ratio of HT-1080 exosomes in the mixture. This machine learning-assisted SERS method enables a new direction through label-free investigation of EV preparations by differentiating cancer cell-derived exosomes from those of healthy. This approach will potentially open up new avenues of research for early detection and monitoring of various diseases, including cancer.

Potential of Mesenchymal Stromal Cell-Derived Extracellular Vesicles as Natural Nanocarriers: Concise Review

Intercellular communication, through direct and indirect cell contact, is mandatory in multicellular organisms. These last years, the microenvironment, and in particular, transfer by extracellular vesicles (EVs), has emerged as a new communication mechanism. Different biological fluids and cell types are common sources of EVs. EVs play different roles, acting as signalosomes, biomarkers, and therapeutic agents. As therapeutic agents, MSC-derived EVs display numerous advantages: they are biocompatible, non-immunogenic, and stable in circulation, and they are able to cross biological barriers. Furthermore, EVs have a great potential for drug delivery. Different EV isolation protocols and loading methods have been tested and compared. Published and ongoing clinical trials, and numerous preclinical studies indicate that EVs are safe and well tolerated. Moreover, the latest studies suggest their applications as nanocarriers. The current review will describe the potential for MSC-derived EVs as drug delivery systems (DDS) in disease treatment, and their advantages. Thereafter, we will outline the different EV isolation methods and loading techniques, and analyze relevant preclinical studies. Finally, we will describe ongoing and published clinical studies. These elements will outline the benefits of MSC-derived EV DDS over several aspects.

Exosomal lncRNAs in gastrointestinal cancer

Gastrointestinal cancer (GIC) remains a leading cause of morbidity and mortality worldwide. Unfortunately, these cancers are diagnosed in advanced metastatic stages due to lack of reliable biomarkers that are sufficiently specific and sensitive in early disease. There has been growing evidence that circulating exosomes can be used to diagnose cancer non-invasively with limited risks and side effects. Furthermore, exosomal long non-coding RNAs (lncRNAs) are emerging as a new class of promising biomarkers in cancer. This review provides an overview of the extraction and detection of exosomal lncRNAs with a focus on their potential role in GIC.

Recent advances in optical label-free characterization of extracellular vesicles

Extracellular vesicles (EVs) are complex biological nanoparticles endogenously secreted by all eukaryotic cells. EVs carry a specific molecular cargo of proteins, lipids, and nucleic acids derived from cells of origin and play a significant role in the physiology and pathology of cells, organs, and organisms. Upon release, they may be found in different body fluids that can be easily accessed via noninvasive methodologies. Due to the unique information encoded in their molecular cargo, they may reflect the state of the parent cell and therefore EVs are recognized as a rich source of biomarkers for early diagnostics involving liquid biopsy. However, body fluids contain a mixture of EVs released by different types of healthy and diseased cells, making the detection of the EVs of interest very challenging. Recent research efforts have been focused on the detection and characterization of diagnostically relevant subpopulations of EVs, with emphasis on label-free methods that simplify sample preparation and are free of interfering signals. Therefore, in this paper, we review the recent progress of the label-free optical methods employed for the detection, counting, and morphological and chemical characterization of EVs. We will first briefly discuss the biology and functions of EVs, and then introduce different optical label-free techniques for rapid, precise, and nondestructive characterization of EVs such as nanoparticle tracking analysis, dynamic light scattering, atomic force microscopy, surface plasmon resonance spectroscopy, Raman spectroscopy, and SERS spectroscopy. In the end, we will discuss their applications in the detection of neurodegenerative diseases and cancer and provide an outlook on the future impact and challenges of these technologies to the field of liquid biopsy via EVs.

Exosome Processing and Characterization Approaches for Research and Technology Development

Exosomes are extracellular vesicles that share components of their parent cells and are attractive in biotechnology and biomedical research as potential disease biomarkers as well as therapeutic agents. Crucial to realizing this potential is the ability to manufacture high-quality exosomes; however, unlike biologics such as proteins, exosomes lack standardized Good Manufacturing Practices for their processing and characterization. Furthermore, there is a lack of well-characterized reference exosome materials to aid in selection of methods for exosome isolation, purification, and analysis. This review informs exosome research and technology development by comparing exosome processing and characterization methods and recommending exosome workflows. This review also provides a detailed introduction to exosomes, including their physical and chemical properties, roles in normal biological processes and in disease progression, and summarizes some of the on-going clinical trials.

Diagnosis of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome With Partial Least Squares Discriminant Analysis: Relevance of Blood Extracellular Vesicles

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), a chronic disease characterized by long-lasting persistent debilitating widespread fatigue and post-exertional malaise, remains diagnosed by clinical criteria. Our group and others have identified differentially expressed miRNA profiles in the blood of patients. However, their diagnostic power individually or in combinations seems limited. A Partial Least Squares-Discriminant Analysis (PLS-DA) model initially based on 817 variables: two demographic, 34 blood analytic, 136 PBMC miRNAs, 639 Extracellular Vesicle (EV) miRNAs, and six EV features, selected an optimal number of five components, and a subset of 32 regressors showing statistically significant discriminant power. The presence of four EV-features (size and z-values of EVs prepared with or without proteinase K treatment) among the 32 regressors, suggested that blood vesicles carry relevant disease information. To further explore the features of ME/CFS EVs, we subjected them to Raman micro-spectroscopic analysis, identifying carotenoid peaks as ME/CFS fingerprints, possibly due to erythrocyte deficiencies. Although PLS-DA analysis showed limited capacity of Raman fingerprints for diagnosis (AUC = 0.7067), Raman data served to refine the number of PBMC miRNAs from our previous model still ensuring a perfect classification of subjects (AUC=1). Further investigations to evaluate model performance in extended cohorts of patients, to identify the precise ME/CFS EV components detected by Raman and to reveal their functional significance in the disease are warranted.

Extracellular Vesicles from Human Cerebrospinal Fluid Are Effectively Separated by Sepharose CL-6B—Comparison of Four Gravity-Flow Size Exclusion Chromatography Methods

Extracellular vesicles (EVs) are a versatile group of cell-secreted membranous nanoparticles present in body fluids. They have an exceptional diagnostic potential due to their molecular content matching the originating cells and accessibility from body fluids. However, methods for EV isolation are still in development, with size exclusion chromatography (SEC) emerging as a preferred method. Here we compared four types of SEC to isolate EVs from the CSF of patients with severe traumatic brain injury. A pool of nine CSF samples was separated by SEC columns packed with Sepharose CL-6B, Sephacryl S-400 or Superose 6PG and a ready-to-use qEV10/70 nm column. A total of 46 fractions were collected and analysed by slot-blot followed by Ponceau staining. Immunodetection was performed for albumin, EV markers CD9, CD81, and lipoprotein markers ApoE and ApoAI. The size and concentration of nanoparticles in fractions were determined by tunable resistive pulse sensing and EVs were visualised by transmission electron microscopy. We show that all four SEC techniques enabled separation of CSF into nanoparticle- and free protein-enriched fractions. Sepharose CL-6B resulted in a significantly higher number of separated EVs while lipoproteins were eluted together with free proteins. Our data indicate that Sepharose CL-6B is suitable for isolation of EVs from CSF and their separation from lipoproteins.

Engineering stem cells to produce exosomes with enhanced bone regeneration effects: an alternative strategy for gene therapy

BACKGROUND

Exosomes derived from stem cells have been widely studied for promoting regeneration and reconstruction of multiple tissues as "cell-free" therapies. However, the applications of exosomes have been hindered by limited sources and insufficient therapeutic potency.

RESULTS

In this study, a stem cell-mediated gene therapy strategy is developed in which mediator mesenchymal stem cells are genetically engineered by bone morphogenetic protein-2 gene to produce exosomes (MSC-BMP2-Exo) with enhanced bone regeneration potency. This effect is attributed to the synergistic effect of the content derived from MSCs and the up-regulated BMP2 gene expression. The MSC-BMP2-Exo also present homing ability to the injured site. The toxic effect of genetical transfection vehicles is borne by mediator MSCs, while the produced exosomes exhibit excellent biocompatibility. In addition, by plasmid tracking, it is interesting to find a portion of plasmid DNA can be encapsulated by exosomes and delivered to recipient cells.

CONCLUSIONS

In this strategy, engineered MSCs function as cellular factories, which effectively produce exosomes with designed and enhanced therapeutic effects. The accelerating effect in bone healing and the good biocompatibility suggest the potential clinical application of this strategy.

Review on Strategies and Technologies for Exosome Isolation and Purification

Exosomes, a nano-sized subtype of extracellular vesicles secreted from almost all living cells, are capable of transferring cell-specific constituents of the source cell to the recipient cell. Cumulative evidence has revealed exosomes play an irreplaceable role in prognostic, diagnostic, and even therapeutic aspects. A method that can efficiently provide intact and pure exosomes samples is the first step to both exosome-based liquid biopsies and therapeutics. Unfortunately, common exosomal separation techniques suffer from operation complexity, time consumption, large sample volumes and low purity, posing significant challenges for exosomal downstream analysis. Efficient, simple, and affordable methods to isolate exosomes are crucial to carrying out relevant researches. In the last decade, emerging technologies, especially microfluidic chips, have proposed superior strategies for exosome isolation and exhibited fascinating performances. While many excellent reviews have overviewed various methods, a compressive review including updated/improved methods for exosomal isolation is indispensable. Herein, we first overview exosomal properties, biogenesis, contents, and functions. Then, we briefly outline the conventional technologies and discuss the challenges of clinical applications of these technologies. Finally, we review emerging exosomal isolation strategies and large-scale GMP production of engineered exosomes to open up future perspectives of next-generation Exo-devices for cancer diagnosis and treatment.

Molecular profiling of extracellular vesicles via charge-based capture using oxide nanowire microfluidics

Extracellular vesicles (EVs) have shown promising features as biomarkers for early cancer diagnoses. The outer layer of cancer cell-derived EVs consists of organotropic metastasis-induced membrane proteins and specifically enriched proteoglycans, and these molecular compositions determine EV surface charge. Although many efforts have been devoted to investigating the correlation between EV subsets obtained through density-, size-, and immunoaffinity-based captures and expressed membrane proteins, understanding the correlation between EV subsets obtained through surface charge-based capture and expressed membrane proteins is lacking. Here, we propose a methodology to profile membrane proteins of EV subsets obtained through surface charge-based capture. Nanowire-induced charge-based capture of EVs and in-situ profiling of EV membrane proteins are the two key methodology points. The oxide nanowires allowed EVs to be obtained through surface charge-based capture due to the diverse isoelectric points of the oxides and the large surface-to-volume ratios of the nanowire structures. And, with the ZnO nanowire device, whose use does not require any purification and concentration processes, we demonstrated the correlation between negatively-charged EV subsets and expressed membrane proteins derived from each cell. Furthermore, we determined that a colon cancer related membrane protein was overexpressed on negatively charged surface EVs derived from colon cancer cells.

Immuno-Acoustic Sorting of Disease-Specific Extracellular Vesicles by Acoustophoretic Force

Methods for the isolation and analysis of extracellular vesicles (EVs) have been extensively explored in the field of life science and in clinical diagnosis in recent years. The separation and efficient recovery of high-purity target EVs from biological samples are important prerequisites in the study of EVs. So far, commonly used methods of EV separation include ultracentrifugation, filtration, solvent precipitation and immunoaffinity capturing. However, these methods suffer from long processing time, EV damage and low enrichment efficiency. The use of acoustophoretic force facilitates the non-contact label-free manipulation of cells based on their size and compressibility but lacks specificity. Additionally, the acoustophoretic force exerted on sub-micron substances is normally weak and insufficient for separation. Here we present a novel immuno-acoustic sorting technology, where biological substances such as EVs, viruses, and biomolecules, can be specifically captured by antibody/receptor coated microparticles through immunoaffinity, and manipulated by an acoustophoretic force exerted on the microparticles. Using immuno-acoustic sorting technology, we successfully separated and purified HER2-positive EVs for further downstream analysis. This method holds great potential in isolating and purifying specific targets such as disease-related EVs from biological fluids and opens new possibilities for the EV-based early diagnosis and prognosis of diseases.

Toward the next-generation phyto-nanomedicines: cell-derived nanovesicles (CDNs) for natural product delivery

Phytochemicals are plant-derived bioactive compounds, which have been widely used for therapeutic purposes. Due to the poor water-solubility, low bioavailability and non-specific targeting characteristic, diverse classes of nanocarriers are utilized for encapsulation and delivery of bio-effective agents. Cell-derived nanovesicles (CDNs), known for exosomes or extracellular vesicles (EVs), are biological nanoparticles with multiple functions. Compared to the artificial counterpart, CDNs hold great potential in drug delivery given the higher stability, superior biocompatibility and the lager capability of encapsulating bioactive molecules. Here, we provide a bench-to-bedside review of CDNs-based nanoplatform, including the bio-origin, preparation, characterization and functionalization. Beyond that, the focus is laid on the therapeutic effect of CDNs-mediated drug delivery for natural products. The state-of-art development as well as some pre-clinical applications of using CDNs for disease treatment is also summarized. It is highly expected that the continuing development of CDNs-based delivery systems will further promote the clinical utilization and translation of phyto-nanomedicines.

miR548ai antagonism attenuates exosome-induced endothelial cell dysfunction

Endothelial cell (EC) and smooth muscle cell (SMC) are major cell types adjacent in the vascular wall. Recent progress indicates that their communication is crucial for vascular homeostasis and pathogenesis. In particular, dysfunctional (proliferative) SMCs through exosomes can induce EC dysfunction (impaired growth). The current study suggests that miR548ai, a rarely known microRNA, may provide a molecular target for protection against SMC/exosome-induced EC dysfunction. We performed microarray profiling of microRNAs of dysfunctional human primary aortic SMCs induced by different cytokines (PDGF-BB, TGFβ1, TNFα, IL1β). Among the microRNAs commonly upregulated by these cytokines, miR548ai showed the most robust changes, as also validated through quantitative PCR. This cytokine-induced miR548ai upregulation was recapitulated in the qPCR determination of SMC-derived exosomal microRNAs. Consistent with SMC-to-EC communication, the exosomes extracted from cytokine-stimulated SMCs impaired human EC proliferation and migration. Of particular interest, this SMC exosomal impingement on ECs was countered by transfection of miR548ai inhibitor microRNA into ECs. Furthermore, the miR548ai inhibitor transfected into SMCs attenuated SMC dysfunction/proliferation. Thus, these results identify miR548ai as a novel target; namely, miR548ai inhibitor mitigates EC dysfunction induced by exosomes derived from dysfunctional SMCs. This new knowledge may aid the future development of microRNA-based treatment of vascular disorders.

Application of ADSCs and their Exosomes in Scar Prevention

Scar is a common way of healing after tissue injury. The poor scar healing will not only cause dysfunction of tissues and organs but also affect the appearance of the patients’ body surface, which causes the pressure of life and spirit to the patients. However, the formation of scar tissue is an extremely complex process and its mechanism is not fully understood. At present, there is no treatment method to eliminate scars completely. Fibroblasts are the most abundant cells in the dermis, which have the ability to synthesize and remodel extracellular matrix (ECM). Myofibroblasts actively participate in the wound healing process and influence the outcome. Therefore, both of them play important roles in wound healing and scar formation. Adipose tissue-derived stem cells (ADSCs) are pluripotent stem cells that can act on target cells by paracrine. Adipose tissue stem cell-derived exosomes (ADSC-Exos) are important secretory substances of ADSCs. They are nanomembrane vesicles that can transport a variety of cellular components and fuse with target cells. In this review, we will discuss the effects of ADSCs and ADSC-Exos on the behavior of fibroblasts and myofibroblasts during wound healing and scarring stage in combination with recent studies.

Stem Cell-Derived Exosomes Potential Therapeutic Roles in Cardiovascular Diseases

Owing to myocardial abnormalities, cardiac ailments are considered to be the major cause of morbidity and mortality worldwide. According to a recent study, membranous vesicles that are produced naturally, termed as "exosomes", have emerged as the potential candidate in the field of cardiac regenerative medicine. A wide spectrum of stem cells has also been investigated in the treatment of cardiovascular diseases (CVD). Exosomes obtained from the stem cells are found to be cardioprotective and offer great hope in the treatment of CVD. The basic nature of exosomes is to deal with the intracellular delivery of both proteins and nucleic acids. This activity of exosomes helps us to rely on them as the attractive pharmaceutical delivery agents. Most importantly, exosomes derived from microRNAs (miRNAs) hold great promise in assessing the risk of CVD, as they serve as notable biomarkers of the disease. Exosomes are small, less immunogenic, and lack toxicity. These nanovesicles harbor immense potential as a therapeutic entity and would provide fruitful benefits if consequential research were focused on their upbringing and development as a useful diagnostic and therapeutic tool in the field of medicine.

Exosomes as cell-derivative carriers in the diagnosis and treatment of central nervous system diseases

Exosomes are extracellular vesicles with the diameter ranging from 50 to 100 nm and are found in different body fluids such as blood, cerebrospinal fluid (CSF), urine and saliva. Like in case of various diseases, based on the parent cells, the content of exosomes (protein, mRNA, miRNA, DNA, lipids and metabolites) varies and thus can be utilized as potential biomarker for diagnosis and prognosis of the brain diseases. Furthermore, utilizing the natural potential exosomes to cross the blood–brain barrier and by specifically decorating it with the ligand as per the desired brain sites therapeutics can be delivered to brain parenchyma. This review article conveys the importance of exosomes and their use in the treatment and diagnosis of brain/central nervous system diseases.