Therapeutic applications of extracellular vesicles: clinical promise and open questions

Relevance of RNA to the therapeutic efficacy of mesenchymal stromal/stem cells extracellular vesicles

Mesenchymal Stromal/Stem Cells (MSCs) are among the most frequently studied cell types in clinical trials, and their small extracellular vesicles (sEVs) are now being extensively investigated for therapeutic applications. The RNA cargo of MSC-sEVs, particularly miRNAs and mRNAs, is widely believed to be a key therapeutic component of these vesicles. In this review, we critically examine using first principles and peer-reviewed literature, whether MSC- extracellular vesicles (MSC-EVs) can deliver sufficient quantity of functional miRNA or mRNA to target compartments within recipient cells to elicit a pharmacological response. Several RNA sequencing studies reveal that miRNAs are underrepresented in the small RNA population of MSC-sEVs compared to the parent MSCs. Additionally, the majority of miRNAs are mature forms that are not associated with Argonaute (AGO) proteins, essential for their function in RNA-induced silencing complexes (RISCs). Compounding this, cellular uptake of EVs is generally inefficient, with less than 1% being internalized, and only a fraction of these reaching the cytosol. This suggests that EVs may not deliver miRNAs in sufficient quantities to meaningfully interact with AGO proteins, either through canonical or non-canonical pathways, or with other proteins like Toll-like receptors (TLRs). Further, MSC-sEV RNAs are generally small, with sizes less than 500 nucleotides indicating that any mRNA present is likely fragmented as the average mammalian mRNA is approximately 2000 nucleotides, a fact confirmed by RNA sequencing data. Together, these findings challenge the notion that RNA, particularly miRNAs and mRNAs, are primary therapeutic attributes of MSC-sEVs.

Human neural stem cell-derived extracellular vesicles protect against ischemic stroke by activating the PI3K/AKT/mTOR pathway

JOURNAL/nrgr/04.03/01300535-202511000-00028/figure1/v/2024-12-20T164640Z/r/image-tiff Human neural stem cell-derived extracellular vesicles exhibit analogous functions to their parental cells, and can thus be used as substitutes for stem cells in stem cell therapy, thereby mitigating the risks of stem cell therapy and advancing the frontiers of stem cell-derived treatments. This lays a foundation for the development of potentially potent new treatment modalities for ischemic stroke. However, the precise mechanisms underlying the efficacy and safety of human neural stem cell-derived extracellular vesicles remain unclear, presenting challenges for clinical translation. To promote the translation of therapy based on human neural stem cell-derived extracellular vesicles from the bench to the bedside, we conducted a comprehensive preclinical study to evaluate the efficacy and safety of human neural stem cell-derived extracellular vesicles in the treatment of ischemic stroke. We found that administration of human neural stem cell-derived extracellular vesicles to an ischemic stroke rat model reduced the volume of cerebral infarction and promoted functional recovery by alleviating neuronal apoptosis. The human neural stem cell-derived extracellular vesicles reduced neuronal apoptosis by enhancing phosphorylation of phosphoinositide 3-kinase, mammalian target of rapamycin, and protein kinase B, and these effects were reversed by treatment with a phosphoinositide 3-kinase inhibitor. These findings suggest that human neural stem cell-derived extracellular vesicles play a neuroprotective role in ischemic stroke through activation of phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway. Finally, we showed that human neural stem cell-derived extracellular vesicles have a good in vivo safety profile. Therefore, human neural stem cell-derived extracellular vesicles are a promising potential agent for the treatment of ischemic stroke.

Injectable extracellular vesicle hydrogels with tunable viscoelasticity for depot vaccine

Extracellular vesicles (EVs) have been actively explored for therapeutic applications in the context of cancer and other diseases. However, the poor tissue retention of EVs has limited the development of EV-based therapies. Here we report a facile approach to fabricating injectable EV hydrogels with tunable viscoelasticity and gelation temperature, by metabolically tagging EVs with azido groups and further crosslinking them with dibenzocyclooctyne-bearing polyethylene glycol via efficient click chemistry. One such EV gel has a gelation temperature of 39.4 °C, enabling in situ gelation of solution-form EVs upon injection into the body. The in situ formed gels are stable for over 4 weeks and can attract immune cells including dendritic cells over time in vivo. We further show that tumor EV hydrogels, upon subcutaneous injection, can serve as a long-term depot for EV-encased tumor antigens, providing an extended time for the modulation of dendritic cells and subsequent priming of tumor-specific CD8+ T cells. The tumor EV hydrogel also shows synergy with anti-PD-1 checkpoint blockade for tumor treatment, and is able to reprogram the tumor microenvironment. As a proof-of-concept, we also demonstrate that EV hydrogels can induce enhanced antibody responses than solution-form EVs over an extended time. Our study yields a facile and universal approach to fabricating injectable EV hydrogels with tunable mechanics and improving the therapeutic efficacy of EV-based therapies.

siRNA-AGO2 complex inhibits bacterial gene translation: A promising therapeutic strategy for superbug infection

Silencing resistance genes of pathogenic bacteria by RNA interference (RNAi) is a potential strategy to fight antibiotic-resistant bacterial infections. Currently, RNAi cannot be achieved in bacteria due to the lack of RNA-induced silencing complex machinery and the difficulty of small interfering RNA (siRNA) delivery. Here, we show that exosomal siRNAs can be efficiently delivered into bacterial cells and can silence target genes primarily through translational repression without mRNA degradation. The exosomal Argonaute 2 (AGO2) protein forms a complex with siRNAs, which is essential for bacterial gene silencing. Both in vitro and in vivo-generated exosome-packaged siRNAs resensitize methicillin-resistant Staphylococcus aureus (MRSA) to methicillin treatment by silencing the mecA gene, which is the primary beta-lactam resistance determinant of MRSA. This approach significantly enhances the therapeutic effect in a mouse model of MRSA infection. In summary, our study provides a method for siRNA delivery to bacteria that may facilitate the treatment of antibiotic-resistant bacterial infection.

Extracellular Vesicles Delivered by a Nanofiber-Hydrogel Composite Enhance Healing In Vivo in a Model of Crohn's Disease Perianal Fistula

Perianal fistulas represent a common, aggressive, and disabling complication of Crohn's disease (CD). Despite recent drug developments, novel surgical interventions as well as multidisciplinary treatment approaches, the outcome is dismal, with >50% therapy failure rates. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) offer potential therapeutic benefits for treating fistulizing CD, due to the pro-regenerative paracrine signals. However, a significant obstacle to clinical translation of EV-based therapy is the rapid clearance and short half-life of EVs in vivo. Here, an injectable, biodegradable nanofiber-hydrogel composite (NHC) microgel matrix that serves as a carrier to deliver MSC-derived EVs to a rat model of CD perianal fistula (PAF) is reported. It is found that EV-loaded NHC (EV-NHC) yields the best fistula healing when compared to other treatment arms. The MRI assessment reveals that the EV-NHC reduces inflammation at the fistula site and promotes tissue healing. The enhanced therapeutic outcomes are contributed by extended local retention and sustained release of EVs by NHC. In addition, the EV-NHC effectively reduces inflammation at the fistula site and promotes tissue healing and regeneration via macrophage polarization and neo-vascularization. This EV-NHC platform provides an off-the-shelf solution that facilitates its clinical translation.

Exosomes: a double-edged sword in cancer immunotherapy

Over the past few decades, immunotherapy has emerged as a powerful strategy to overcome the limitations of conventional cancer treatments. The use of extracellular vesicles, particularly exosomes, which carry cargoes capable of modulating the immune response, has been extensively explored as a potential therapeutic approach in cancer immunotherapy. Exosomes can deliver their cargo to target cells, thereby influencing their phenotype and immunomodulatory functions. They exhibit either immunosuppressive or immune-activating characteristics, depending on their internal contents. These exosomes originate from diverse cell sources, and their internal contents can vary, suggesting that there may be a delicate balance between immune suppression and stimulation when utilizing them for immunotherapy. Therefore, a thorough understanding of the molecular mechanisms underlying the role of exosomes in cancer progression is essential. This review focuses on the molecular mechanisms driving exosome function and their impact on the tumor microenvironment (TME), highlighting the intricate balance between immune suppression and activation that must be navigated in exosome-based therapies. Additionally, it underscores the challenges and ongoing efforts to optimize exosome-based immunotherapies, thereby making a significant contribution to the advancement of cancer immunotherapy research.

Extracellular vesicles and preterm infant diseases

With the continuous improvement in perinatal care, the number of viable preterm infants is gradually increasing, along with the rise in preterm-related diseases such as necrotizing enterocolitis, bronchopulmonary dysplasia, perinatal brain injury, retinopathy of prematurity, and sepsis. Due to the unique pathophysiology of preterm infants, diagnosing and treating these diseases has become particularly challenging, significantly affecting their survival rate and long-term quality of life. Extracellular vesicles (EVs), as key mediators of intercellular communication, play an important regulatory role in the pathophysiology of these diseases. Because of their biological characteristics, EVs could serve as biomarkers and potential therapeutic agents for preterm-related diseases. This review summarizes the biological properties of EVs, their relationship with preterm-related diseases, and their prospects for diagnosis and treatment. EVs face unique challenges and opportunities for clinical applications.

Extracellular vesicles and miRNA-based therapies in triple-negative breast cancer: advances and clinical perspectives

Triple-negative breast cancer (TNBC) is one of the most aggressive and challenging subtypes for treatment, due to the lack of hormone receptors and the human epidermal growth factor receptor 2 (HER2) protein. The identification of new molecular targets is important for the development of targeted and specific therapies for TNBC patients. MicroRNAs (miRNAs) have emerged as promising molecular targets, being involved in cellular processes such as cell survival, apoptosis, differentiation, carcinogenesis, and metastasis. Extracellular vesicles (EVs) have gained prominence in areas such as drug delivery, immune modulation, biomarkers for diagnosis and prognosis, and therapeutics, due to their use as vehicles for the delivery of miRNAs, regulation of gene expression, and development of combined therapeutic strategies. In particular, mesenchymal stem cell-derived EVs (MSC-derived EVs) can transfer proteins, mRNAs/miRNAs, or DNA molecules and are being considered safer treatment options due to their inability to directly form tumors and contain lower amounts of membrane proteins such as MHC molecules. Numerous studies have highlighted the role of miRNAs in EVs in TNBC tumorigenesis, with a focus on diagnosis, prognosis, treatment selection, and monitoring. However, the development of therapies with EVs, especially MSC-derived EVs, is still in its infancy. Therefore, the aim of this review is to address new therapeutic strategies based on the delivery of miRNAs through EVs, with a focus on MSC-derived EVs, for the treatment of TNBC as an innovative therapy in oncology.

Therapeutic potential of mesenchymal stem cell-derived extracellular vesicles in ischemic stroke: A meta-analysis of preclinical studies

BACKGROUND

Ischemic stroke (IS) remains a significant global health burden, necessitating the development of novel therapeutic strategies. This study aims to systematically evaluate the therapeutic effects of mesenchymal stem cell-derived exosomes (MSC-Exos) on IS outcomes in rodent models.

METHODS

A comprehensive literature search was conducted across multiple databases to identify studies investigating the effects of MSC-Exos on rodent models of IS. Following rigorous inclusion and exclusion criteria, 73 high-quality studies were selected for meta-analysis. Primary outcomes included reductions in infarct volume/ratio and improvements in functional recovery scores. Data extraction and analysis were performed using RevMan 5.3 software.

RESULTS

Pooled data indicated that MSC-Exos administration significantly reduced infarct size and improved functional recovery scores in rodent models of IS. Treatment within 24 hours and beyond 24 hours of stroke induction both demonstrated substantial reductions in infarct volume/ratio compared to controls. Furthermore, MSC-Exos-treated groups exhibited marked improvements in functional recovery, as assessed by various neurobehavioral tests. The meta-analysis showed no significant publication bias, and heterogeneity levels were acceptable.

CONCLUSIONS

MSC-Exos reveal significant therapeutic potential for IS, with evidence supporting their efficacy in reducing infarct size and enhancing functional recovery in preclinical rodent models. These findings pave the way for further research and potential clinical translation.

Thermoresponsive gel embedding extracellular vesicles from adipose stromal cells improves the healing of colonic anastomoses following irradiation in rats

Anastomotic leak occurrence is a severe complication after colorectal surgery. Considering the difficulty of treating these leaks and their impact on patient care, there is a strong need for an efficient prevention strategy. We evaluated a combination of extracellular vesicles (EVs) from rat adipose-derived stromal cells with a thermoresponsive gel, Pluronic® F127 (PF-127) to prevent anastomotic leaks. The pro-regenerative and immunomodulatory potencies of EVs are assessed in vitro. In vivo efficacy are assessed in rat with a colonic anastomosis model after irradiation. Endoscopic, anatomical and histological data show a consistent effect of EVs + gel on the healing of colonic anastomosis. These results are illustrated by a smaller anastomotic ulcer size, less fibrosis and less inflammatory infiltrations in the EVs + gel group. This multi-modal investigation is the first to point-out the translational potential of EVs combined with PF-127 for the healing of high-risk colorectal anastomosis.

Molecular Determinants of Neutrophil Extracellular Vesicles That Drive Cartilage Regeneration in Inflammatory Arthritis

OBJECTIVE

This study was undertaken to establish the potential therapeutic profile of neutrophil-derived extracellular vesicles (EVs) in experimental inflammatory arthritis and associate pharmacological activity with specific EV components, focusing on microRNAs.

METHODS

Neutrophil EVs were administered intra-articularly through a prophylactic or therapeutic protocol to male C57BL/6 mice undergoing serum-transfer-induced inflammatory arthritis. Transcriptomic analysis of knees was performed on joints following EV administration, naive and arthritic mice (untreated; n = 4/group) and EV-treated diseased mice (intra-articular administration) with contralateral (vehicle-treated; n = 8/group). Comparison of healthy donor and patients with rheumatoid arthritis (RA) neutrophil EVs was performed.

RESULTS

EVs afforded cartilage protection with an increase in collagen-II and reduced collagen-X expression within the joint. To gain mechanistic insights, RNA sequencing of the arthritic joints was conducted. A total of 5,231 genes were differentially expressed (P < 0.05), with 257 unique to EV treatment. EVs affected key regenerative pathways involved in joint development, including Wnt and Notch signaling. This wealth of genomic alteration prompted to identify microRNAs in EVs, 10 of which are associated with RA. As a proof of concept, we focused on miR-455-3p, which was detected in both healthy donor and RA EVs. EV addition to chondrocyte cultures elevated miR-455-3p and exerted anticatabolic effects upon interleukin-1β stimulation; these effects were blocked by actinomycin or miR-455-3p antagomir.

CONCLUSION

Neutrophils from patients with RA yielded EVs with composition, efficacy, and miR-455-3p content similar to those of healthy volunteers, suggesting that neutrophil EVs could be developed as an autologous treatment to protect and repair joint tissue of patients affected by inflammatory arthritides.

Hyaluronic acid-modified extracellular vesicles for targeted doxorubicin delivery in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), a prevalent and deadly cancer, poses a significant challenge with current treatments due to limitations such as poor stability, off-target effects, and severe side effects. Extracellular vesicles (EVs), derived from tumor cells, have the remarkable ability to home back to their cells of origin and can serve as Trojan horses for drug delivery. CD44, a cell surface glycoprotein, promotes cancer stem cell-like properties and is linked to poor prognosis and resistance to chemotherapy in HCC. Therefore, targeting CD44-expressing HCC cells is of interest in the development of novel therapeutic strategies for the treatment of HCC. In this study, we developed tumor cell-derived EVs (TEVs) functionalized with hyaluronic acid (HA) to serve as natural carriers for the precise delivery of doxorubicin (Dox), which specifically targets HCC cells expressing CD44. Our results demonstrated that HA-engineered EVs (HA-EVs) significantly enhanced Dox accumulation within HCC cells. In a mouse model, HA-EVs effectively delivered Dox to tumors, suppressing their growth and progression while minimizing systemic toxicity. This study demonstrates the potential of HA-functionalized EVs as a novel and targeted therapeutic platform for HCC, offering a valuable strategy for improving drug delivery and patient outcomes. This study presents a promising strategy to advance targeted chemotherapy for HCC and address the challenges associated with conventional treatments. Engineered HA-functionalized EVs offer a tailored and efficient approach to increase drug delivery precision, underscoring their potential as a novel therapeutic platform in the realm of HCC treatment.

Enrichment protocols for human conjunctival extracellular vesicles and their characterization

The understanding of the role played by extracellular vesicles (EVs) in different tissues has improved significantly in the last years, but remains limited concerning the conjunctiva, a complex eye tissue whose role is pivotal for corneal protection. Here, we conducted a comparative study to isolate and characterize EVs from human conjunctival epithelial (IM-HConEpiC) and human conjunctival mesenchymal stromal cell (Conj-MSCs) secretomes using different isolation methods: differential ultracentrifugation (UC), and a combination of ultrafiltration (UF) with precipitation or size exclusion chromatography (SEC). EVs were characterized by total protein content, size, morphology, and expression of protein markers. EV functional effect was tested in an in vitro oxidative stress model. We successfully recovered EVs with the three methods, although significantly higher yields were obtained with UF-precipitation. Dynamic light scattering analysis confirmed the presence of nano-sized particles, being UC-isolated EVs larger than those isolated by UF-precipitation and UF-SEC. Atomic Force Microscopy showed EVs with a slightly ellipsoidal morphology. EVs enriched with UF-precipitation method were further analyzed, confirming the expression of Alix, CD63, TSG101, and Syntenin-1 by Western blotting and showing that Conj-MSC-derived EVs significantly reduced oxidative stress on IM-HConEpiC. Therefore, we conclude that UF-precipitation is the most efficient method for conjunctival EV enrichment.

The Potential Role of Exosomes in Ocular Surface and Lacrimal Gland Regeneration

PURPOSE

Dry eye disease (DED), a multifactorial disease of the lacrimal system, manifests itself in patients with various symptoms such as itching, inflammation, discomfort and visual impairment. In its most severe forms, it results in the breakdown of the vital tissues of lacrimal functional unit and carries the risk of vision loss. Despite the frequency of occurrence of the disease, there are no effective curative treatment options available to date. Treatment using stem cells and its secreted factors could be a promising approach in the regeneration of damaged tissues of ocular surface. The treatment using secreted factors as well as extracellular vesicles has been demonstrated beneficial effects in various ocular surface diseases. This review provides insights on the usage of stem cell derived exosomes as a promising therapy against LG dysfunction induced ADDE for ocular surface repair.

METHODS

In order to gain an overview of the existing research in this field, literature search was carried out using the PubMed, Medline, Scopus and Web of Science databases. This review is based on 164 publications until June 2024 and the literature search was carried out using the key words "exosomes", "lacrimal gland regeneration", "exosomes in lacrimal dysfunction".

RESULTS

The literature and studies till date suggest that exosomes and other secreted factors from stem cells have demonstrated beneficial effects on damaged ocular tissues in various ocular surface diseases. Exosomal cargo plays a crucial role in regenerating tissues by promoting homeostasis in the lacrimal system, which is often compromised in severe cases of dry eye disease. Exosome therapy shows promise as a regenerative therapy, potentially addressing the lack of effective curative treatments available for patients with dry eye disease.

CONCLUSION

Stem cell-derived exosomes represent a promising, innovative approach as a new treatment option for ADDE. By targeting lacrimal gland dysfunction and enhancing ocular surface repair, exosome therapy offers potential for significant advances in dry eye disease management. Future research is needed to refine the application of this therapy, optimize delivery methods, and fully understand its long-term efficacy in restoring ocular health.

Exosomes on the development and progression of renal fibrosis

Renal fibrosis is a prevalent pathological alteration that occurs throughout the progression of primary and secondary renal disorders towards end-stage renal disease. As a complex and irreversible pathophysiological phenomenon, it includes a sequence of intricate regulatory processes at the molecular and cellular levels. Exosomes are a distinct category of extracellular vesicles that play a crucial role in facilitating intercellular communication. Multiple pathways are regulated by exosomes produced by various cell types, including tubular epithelial cells and mesenchymal stem cells, in the context of renal fibrosis. Furthermore, research has shown that exosomes present in bodily fluids, including urine and blood, may be indicators of renal fibrosis. However, the regulatory mechanism of exosomes in renal fibrosis has not been fully elucidated. This article reviewed and analysed the various mechanisms by which exosomes regulate renal fibrosis, which may provide new ideas for further study of the pathophysiological process of renal fibrosis and targeted treatment of renal fibrosis with exosomes.

Beneficial Effects of Human Schwann Cell-Derived Exosomes in Mitigating Secondary Damage After Penetrating Ballistic-Like Brain Injury

There is a growing body of evidence that the delivery of cell-derived exosomes normally involved in intracellular communication can reduce secondary injury mechanisms after brain and spinal cord injury and improve outcomes. Exosomes are nanometer-sized vesicles that are released by Schwann cells and may have neuroprotective effects by reducing post-traumatic inflammatory processes as well as promoting tissue healing and functional recovery. The purpose of this study was to evaluate the beneficial effects of human Schwann-cell exosomes (hSC-Exos) in a severe model of penetrating ballistic-like brain injury (PBBI) in rats and investigate effects on multiple outcomes. Human Schwann cell processing protocols followed Current Good Manufacturing Practices (cGMP) with exosome extraction and purification steps approved by the Food and Drug Administration for an expanded access single ALS patient Investigational New Drug. Anesthetized male Sprague-Dawley rats (280-350g) underwent PBBI surgery or Sham procedures and, starting 30 min after injury, received either a dose of hSC-Exos or phosphate-buffered saline through the jugular vein. At 48h after PBBI, flow cytometry analysis of cortical tissue revealed that hSC-Exos administration reduced the number of activated microglia and levels of caspase-1, a marker of inflammasome activation. Neuropathological analysis at 21 days showed that hSC-Exos treatment after PBBI significantly reduced overall contusion volume and decreased the frequency of Iba-1 positive activated and amoeboid microglia by immunocytochemical analysis. This study revealed that the systemic administration of hSC-Exos is neuroprotective in a model of severe TBI and reduces secondary inflammatory injury mechanisms and histopathological damage. The administration of hSC-Exos represents a clinically relevant cell-based therapy to limit the detrimental effects of neurotrauma or other progressive neurological injuries by impacting multiple pathophysiological events and promoting neurological recovery.

Targeted gene delivery systems for T-cell engineering

T lymphocytes are indispensable for the host systems of defense against pathogens, tumors, and environmental threats. The therapeutic potential of harnessing the cytotoxic properties of T lymphocytes for antigen-specific cell elimination is both evident and efficacious. Genetically engineered T-cells, such as those employed in CAR-T and TCR-T cell therapies, have demonstrated significant clinical benefits in treating cancer and autoimmune disorders. However, the current landscape of T-cell genetic engineering is dominated by strategies that necessitate in vitro T-cell isolation and modification, which introduce complexity and prolong the development timeline of T-cell based immunotherapies. This review explores the complexities of gene delivery systems designed for T cells, covering both viral and nonviral vectors. Viral vectors are known for their high transduction efficiency, yet they face significant limitations, such as potential immunogenicity and the complexities involved in large-scale production. Nonviral vectors, conversely, offer a safer profile and the potential for scalable manufacturing, yet they often struggle with lower transduction efficiency. The pursuit of gene delivery systems that can achieve targeted gene transfer to T cell without the need for isolation represents a significant advancement in the field. This review assesses the design principles and current research progress of such systems, highlighting the potential for in vivo gene modification therapies that could revolutionize T-cell based treatments. By providing a comprehensive analysis of these systems, we aim to contribute valuable insights into the future development of T-cell immunotherapy.

Unveiling the promise: Exosomes as game-changers in anti-infective therapy

Extracellular vesicles (EVs)-based intercellular communication (through exosomes, microvesicles, and apoptotic bodies) is conserved across all kingdoms of life. In recent years, exosomes have gained much attention for targeted pharmaceutical administration due to their unique features, nanoscale size, and capacity to significantly contribute to cellular communication. As drug delivery vehicles, exosomes have several advantages over alternative nanoparticulate drug delivery technologies. A key advantage lies in their comparable makeup to the body's cells, which makes them non-immunogenic. However, exosomes vesicles face several challenges, including a lack of an effective and standard production technique, decreased drug loading capacity, limited characterization techniques, and underdeveloped isolation and purification procedures. Exosomes are well known for their long-term safety and natural ability to transport intercellular nucleic acids and medicinal compounds across the blood-brain-barrier (BBB). Therefore, in addition to revealing new insights into exosomes' distinctiveness, the growing availability of new analytical tools may drive the development of next-generation synthetic systems. Herein, light is shed on exosomes as drug delivery vehicles in anti-infective therapy by reviewing the literature on primary articles published between 2002 and 2023. Additionally, the benefits and limitations of employing exosomes as vehicles for therapeutic drug delivery are also discussed.

Exosomes as promising bioactive materials in the treatment of spinal cord injury

Patients with spinal cord injury (SCI) have permanent devastating motor and sensory disabilities. Secondary SCI is known for its complex progression and presents with sophisticated aberrant inflammation, vascular changes, and secondary cellular dysfunction, which aggravate the primary damage. Since their initial discovery, the potent neuroprotective effects and powerful delivery abilities of exosomes (Exos) have been reported in different research fields, including SCI. In this study, we summarize therapeutic advances related to the application of Exos in preclinical animal studies. Subsequently, we discuss the mechanisms of action of Exos derived from diverse cell types, including neurogenesis, angiogenesis, blood-spinal cord barrier preservation, anti-apoptosis, and anti-inflammatory potential. We also evaluate the relationship between the Exo delivery cargo and signaling pathways. Finally, we discuss the challenges and advantages of using Exos to offer innovative insights regarding the development of efficient clinical strategies for SCI.

Engineering strategies for apoptotic bodies

Extracellular vesicles (EVs) are lipid bilayer vesicles containing proteins, lipids, nucleic acids, and metabolites secreted by cells under various physiological and pathological conditions that mediate intercellular communication. The main types of EVs include exosomes, microvesicles, and apoptotic bodies (ABs). ABs are vesicles released during the terminal stages of cellular apoptosis, enriched with diverse biological entities and characterized by distinct morphological features. As a result, ABs possess great potential in fields like disease diagnosis, immunotherapy, regenerative therapy, and drug delivery due to their specificity, targeting capacity, and biocompatibility. However, their therapeutic efficacy is notably heterogeneous, and an overdose can lead to side effects such as accumulation in the liver, spleen, lungs, and gastrointestinal system. Through bioengineering, the properties of ABs can be optimized to enhance drug-loading efficiency, targeting precision, and multifunctionality for clinical implementations. This review focuses on strategies such as transfection, sonication, electroporation, surface engineering, and integration with biomaterials to enable ABs to load cargoes and enhance targeting, providing insights into the engineering of ABs.

3D printing of interferon γ-preconditioned NSC-derived exosomes/collagen/chitosan biological scaffolds for neurological recovery after TBI

The reconstruction of neural function and recovery of chronic damage following traumatic brain injury (TBI) remain significant clinical challenges. Exosomes derived from neural stem cells (NSCs) offer various benefits in TBI treatment. Numerous studies confirmed that appropriate preconditioning methods enhanced the targeted efficacy of exosome therapy. Interferon-gamma (IFN-γ) possesses immunomodulatory capabilities and is widely involved in neurological disorders. In this study, IFN-γ was employed for preconditioning NSCs to enhance the efficacy of exosome (IFN-Exo, IE) for TBI. miRNA sequencing revealed the potential of IFN-Exo in promoting neural differentiation and modulating inflammatory responses. Through low-temperature 3D printing, IFN-Exo was combined with collagen/chitosan (3D-CC-IE) to preserve the biological activity of the exosome. The delivery of exosomes via biomaterial scaffolds benefited the retention and therapeutic potential of exosomes, ensuring that they could exert long-term effects at the injury site. The 3D-CC-IE scaffold exhibited excellent biocompatibility and mechanical properties. Subsequently, 3D-CC-IE scaffold significantly improved impaired motor and cognitive functions after TBI in rat. Histological results showed that 3D-CC-IE scaffold markedly facilitated the reconstruction of damaged neural tissue and promoted endogenous neurogenesis. Further mechanistic validation suggested that IFN-Exo alleviated neuroinflammation by modulating the MAPK/mTOR signaling pathway. In summary, the results of this study indicated that 3D-CC-IE scaffold engaged in long-term pathophysiological processes, fostering neural function recovery after TBI, offering a promising regenerative therapy avenue.

Engineering macrophages and their derivatives: A new hope for antitumor therapy

Macrophages are central to the immune system and are found in nearly all tissues. Recently, the development of therapies based on macrophages has attracted significant interest. These therapies utilize macrophages' key roles in immunity, their ability to navigate biological barriers, and their tendency to accumulate in tumors. This review explores the advancement of macrophage-based treatments. We discuss the bioengineering of macrophages for improved anti-tumor effects, the use of CAR macrophage therapy for targeting cancer cells, and macrophages as vehicles for therapeutic delivery. Additionally, we examine engineered macrophage products, like extracellular vesicles and membrane-coated nanoparticles, for their potential in precise and less toxic tumor therapy. Challenges in moving these therapies from research to clinical practice are also highlighted. The aim is to succinctly summarize the current status, challenges, and future directions of engineered macrophages in cancer therapy.

Advancing cancer therapeutics: Integrating scalable 3D cancer models, extracellular vesicles, and omics for enhanced therapy efficacy

Cancer remains as one of the highest challenges to human health. However, anticancer drugs exhibit one of the highest attrition rates compared to other therapeutic interventions. In part, this can be attributed to a prevalent use of in vitro models with limited recapitulative potential of the in vivo settings. Three dimensional (3D) models, such as tumor spheroids and organoids, offer many research opportunities to address the urgent need in developing models capable to more accurately mimic cancer biology and drug resistance profiles. However, their wide adoption in high-throughput pre-clinical studies is dependent on scalable manufacturing to support large-scale therapeutic drug screenings and multi-omic approaches for their comprehensive cellular and molecular characterization. Extracellular vesicles (EVs), which have been emerging as promising drug delivery systems (DDS), stand to significantly benefit from such screenings conducted in realistic cancer models. Furthermore, the integration of these nanomedicines with 3D cancer models and omics profiling holds the potential to deepen our understanding of EV-mediated anticancer effects. In this chapter, we provide an overview of the existing 3D models used in cancer research, namely spheroids and organoids, the innovations in their scalable production and discuss how omics can facilitate the implementation of these models at different stages of drug testing. We also explore how EVs can advance drug delivery in cancer therapies and how the synergy between 3D cancer models and omics approaches can benefit in this process.

Integration of photomagnetic bimodal imaging to monitor an autogenous exosome loaded platform: unveiling strong targeted retention effects for guiding the photothermal and magnetothermal therapy in a mouse prostate cancer model

BACKGROUND

Prostate cancer (PCa) is the most prevalent cancer among males, emphasizing the critical need for precise diagnosis and treatment to enhance patient prognosis. Recent studies have extensively utilized urine exosomes from patients with cancer for targeted delivery. This study aimed to employ highly sensitive magnetic particle imaging (MPI) and fluorescence molecular imaging (FMI) to monitor the targeted delivery of an exosome-loaded platform at the tumour site, offering insights into a potential combined photothermal and magnetic thermal therapy regime for PCa.

RESULTS

MPI and FMI were utilized to monitor the in vivo retention performance of exosomes in a prostate tumour mouse model. The exosome-loaded platform exhibited robust homologous targeting ability during imaging (SPIONs@EXO-Dye:66·48%±3·85%; Dye-SPIONs: 34·57%±7·55%, **P<0·01), as verified by in vitro imaging and in vitro tissue Prussian blue staining.

CONCLUSIONS

The experimental data underscore the feasibility of using MPI for in vivo PCa imaging. Furthermore, the exosome-loaded platform may contribute to the precise diagnosis and treatment of PCa.

Extracellular vesicles enhance the in vivo antitumor effects of millettia species-derived compounds in chronic myelogenous leukemia therapy

Several Millettia species are being investigated as medicinal ingredients due to their promising anti-cancer and anti-inflammatory properties. However, the application of Millettia species-derived compounds has been severely hindered by their poor aqueous solubility, rapid metabolism, and low bioavailability. Extracellular vesicles (EVs), which as membrane-bound phospholipid vesicle initiatively secreted through a variety of mammalian cells, are increasingly recognized as promising drug delivery vehicles. Therefore, EVs are with great potential to enhance both the stability and efficacy of the Millettia species-derived compounds in treatment. In this study, extracellular vesicles derived from chronic myelogenous leukemia cells are developed for delivering the extracts of Millettia speciosa Champ and Millettia pachyloba Drake-derived Homobutein. Notably, Homobutein-loaded EV (hEV) formed a stable and homogenous nanosized particle with high entrapment efficiency up to 55.7%. Moreover, EVs loaded with Homobutein were significantly more potent than free drugs in inhibiting K562 cell proliferation. The results demonstrated that intravenous injection of EV loaded with Homobutein effectively inhibits tumor growth in tumor-bearing mice compared to free Homobutein. Hence, this strategy can effectively enhance the efficacy of Millettia species-derived drugs in chronic myelogenous leukemia therapy.

Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles

This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.

The engineered exosomes targeting ferroptosis: A novel approach to reverse immune checkpoint inhibitors resistance

Immune checkpoint inhibitors (ICIs) have been extensively used in immunological therapy primarily due to their ability to prolong patient survival. Although ICIs have achieved success in cancer treatment, the resistance of ICIs should not be overlooked. Ferroptosis is a newly found cell death mode characterized by the accumulation of reactive oxygen species (ROS), glutathione (GSH) depletion, and glutathione peroxidase 4 (GPX4) inactivation, which has been demonstrated to be beneficial to immunotherapy and combining ferroptosis and ICIs to exploit new immunotherapies may reverse ICIs resistance. Exosomes act as mediators in cell-to-cell communication that may regulate ferroptosis to influence immunotherapy through the secretion of biological molecules. Thus, utilizing exosomes to target ferroptosis has opened up exciting possibilities for reversing ICIs resistance. In this review, we summarize the mechanisms of ferroptosis improving ICIs therapy and how exosomes regulate ferroptosis through adjusting iron metabolism, blocking the ROS accumulation, controlling ferroptosis defense systems, and influencing classic signaling pathways and how engineered exosomes target ferroptosis and improve ICIs efficiency.

Cargo exchange between human and bacterial extracellular vesicles in gestational tissues: a new paradigm in communication and immune development

Host-bacteria and bacteria-bacteria interactions can be facilitated by extracellular vesicles (EVs) secreted by both human and bacterial cells. Human and bacterial EVs (BEVs) propagate and transfer immunogenic cargos that may elicit immune responses in nearby or distant recipient cells/tissues. Hence, direct colonization of tissues by bacterial cells is not required for immunogenic stimulation. This phenomenon is important in the feto-maternal interface, where optimum tolerance between the mother and fetus is required for a successful pregnancy. Though the intrauterine cavity is widely considered sterile, BEVs from diverse sources have been identified in the placenta and amniotic cavity. These BEVs can be internalized by human cells, which may help them evade host immune surveillance. Though it appears logical, whether bacterial cells internalize human EVs or human EV cargo is yet to be determined. However, the presence of BEVs in placental tissues or amniotic cavity is believed to trigger a low-grade immune response that primes the fetal immune system for ex-utero survival, but is insufficient to disrupt the progression of pregnancy or cause immune intolerance required for adverse pregnancy events. Nevertheless, the exchange of bioactive cargos between human and BEVs, and the mechanical underpinnings and health implications of such interactions, especially during pregnancy, are still understudied. Therefore, while focusing on the feto-maternal interface, we discussed how human cells take up BEVs and whether bacterial cells take up human EVs or their cargo, the exchange of cargos between human and BEVs, host cell (feto-maternal) inflammatory responses to BEV immunogenic stimulation, and associations of these interactions with fetal immune priming and adverse reproductive outcomes such as preeclampsia and preterm birth.

Molecular Pathogenesis of Ischemic and Hemorrhagic Strokes: Background and Therapeutic Approaches

Stroke represents one of the neurological diseases most responsible for death and permanent disability in the world. Different factors, such as thrombus, emboli and atherosclerosis, take part in the intricate pathophysiology of stroke. Comprehending the molecular processes involved in this mechanism is crucial to developing new, specific and efficient treatments. Some common mechanisms are excitotoxicity and calcium overload, oxidative stress and neuroinflammation. Furthermore, non-coding RNAs (ncRNAs) are critical in pathophysiology and recovery after cerebral ischemia. ncRNAs, particularly microRNAs, and long non-coding RNAs (lncRNAs) are essential for angiogenesis and neuroprotection, and they have been suggested to be therapeutic, diagnostic and prognostic tools in cerebrovascular diseases, including stroke. This review summarizes the intricate molecular mechanisms underlying ischemic and hemorrhagic stroke and delves into the function of miRNAs in the development of brain damage. Furthermore, we will analyze new perspectives on treatment based on molecular mechanisms in addition to traditional stroke therapies.

ExoDS: a versatile exosome-based drug delivery platform to target cancer cells and cancer stem cells

Chemotherapy drugs like doxorubicin (Dox) are widely used in middle-income countries around the world to treat various types of cancers, including breast cancer. Although they are toxic, they are still widely used to treat cancer. Delivering chemotherapy drugs directly to cancer cells to reduce side effects remains a challenge. Moreover, modern research gave rise to cancer stem cell theory, which implicated cancer stem cells in tumor initiation, progression, and relapse. This makes it imperative to target cancer stem cells to achieve complete remission. Our work highlights the development of an exosome-based targeted drug delivery vehicle. These exosomes were isolated from mature dendritic cells (mDCs) and encapsulated with doxorubicin (ExoDS). Our results showed that ExoDS specifically targeted breast cancer cells and breast cancer stem cells. Further analysis revealed that ExoDS did not induce any significant apoptosis in healthy mammary cells and peripheral blood mononuclear cells (PBMCs) isolated from healthy individuals and breast cancer patients. ExoDS was also found to target circulating tumor cells (CTCs) isolated from patient blood. ExoDS also showed equal efficiency compared to free doxorubicin in vivo. We also observed that ExoDS reduced the expression of cancer stem cell markers in murine tumor tissues. Altogether, this work provides novel insights into how mDC-derived exosomes can be used to specifically target cancer cells and cancer stem cells.

Extracellular vesicles-powered immunotherapy: Unleashing the potential for safer and more effective cancer treatment

Cancer treatment has seen significant advancements with the introduction of Onco-immunotherapies (OIMTs). Although some of these therapies have received approval for use, others are either undergoing testing or are still in the early stages of development. Challenges persist in making immunotherapy widely applicable to cancer treatment. To maximize the benefits of immunotherapy and minimize potential side effects, it's essential to improve response rates across different immunotherapy methods. A promising development in this area is the use of extracellular vesicles (EVs) as novel delivery systems. These small vesicles can effectively deliver immunotherapies, enhancing their effectiveness and reducing harmful side effects. This article discusses the importance of integrating nanomedicines into OIMTs, highlighting the challenges with current anti-OIMT methods. It also explores key considerations for designing nanomedicines tailored for OIMTs, aiming to improve upon existing immunotherapy techniques. Additionally, the article looks into innovative approaches like biomimicry and the use of natural biomaterial-based nanocarriers (NCs). These advancements have the potential to transform the delivery of immunotherapy. Lastly, the article addresses the challenges of moving OIMTs from theory to clinical practice, providing insights into the future of using advanced nanotechnology in cancer treatment.

Adipose tissue macrophage-derived microRNA-210-3p disrupts systemic insulin sensitivity by silencing GLUT4 in obesity

Management of chronic obesity-associated metabolic disorders is a key challenge for biomedical researchers. During chronic obesity, visceral adipose tissue (VAT) undergoes substantial transformation characterized by a unique lipid-rich hypoxic AT microenvironment which plays a crucial role in VAT dysfunction, leading to insulin resistance (IR) and type 2 diabetes. Here, we demonstrate that obese AT microenvironment triggers the release of miR-210-3p microRNA-loaded extracellular vesicles from adipose tissue macrophages, which disseminate miR-210-3p to neighboring adipocytes, skeletal muscle cells, and hepatocytes through paracrine and endocrine actions, thereby influencing insulin sensitivity. Moreover, EVs collected from Dicer-silenced miR-210-3p-overexpressed bone marrow-derived macrophages induce glucose intolerance and IR in lean mice. Mechanistically, miR-210-3p interacts with the 3'-UTR of GLUT4 mRNA and silences its expression, compromising cellular glucose uptake and insulin sensitivity. Therapeutic inhibition of miR-210-3p in VAT notably rescues high-fat diet-fed mice from obesity-induced systemic glucose intolerance. Thus, targeting adipose tissue macrophage-specific miR-210-3p during obesity could be a promising strategy for managing IR and type 2 diabetes.

Collagen sponge scaffolds loaded with Trichostatin A pretreated BMSCs-derived exosomes regulate macrophage polarization to promote skin wound healing

The process of wound healing includes the inflammatory stage, which plays an important role. Macrophages can promote inflammatory response and also promote angiogenesis, wound contraction and tissue remodeling required for wound healing. It is crucial to promote macrophages to polarize from M1 pro-inflammatory phenotype to M2 anti-inflammatory phenotype at a critical time for the quality of wound healing. Because mesenchymal stem cell-derived exosomes have broad therapeutic prospects in the field of tissue repair and regeneration, in this study, we explored whether trichostatin A pretreated bone marrow mesenchymal stem cells (BMSCs)-derived exosomes (T-Exo) could promote wound healing by binding to biomaterial scaffolds through certain anti-inflammatory effects. In the cell experiment, we established macrophage inflammation model and then treated with T-Exo, and finally detected the expression levels of macrophage polarization proteins CD206, CD86 and TNF-α, iNOS, and Arg-1 by Western Blot and immunofluorescence staining; detected the expression levels of inflammation-related genes TNF-α, iNOS, IL-1β, IL-10 and anti-inflammatory genes CD206 and Arg-1 by qRT-PCR; explored the promoting ability of T-Exo to promote cell migration and tube formation by cell scratch experiment and angiogenesis experiment. The results showed that T-Exo could promote the polarization of M1 macrophages to M2 macrophages, and promote the migration and angiogenesis of HUVECs. Because TSA pretreatment may bring about changes in the content and function of BMSCs-derived exosomes, proteomic analysis was performed on T-Exo and unpretreated BMSCs-derived exosomes (Exo). The results showed that the differentially expressed proteins in T-Exo were related to some pathways that promote angiogenesis, cell migration, proliferation, and re-epithelialization. Then, exosome/collagen sponge (T-Exo/Col) biological scaffolds were prepared, and the physicochemical properties and biocompatibility of the scaffolds were investigated. Animal skin wound models were established, and the therapeutic effect and anti-inflammatory effect of T-Exo/Col in wound repair were evaluated by small animal in vivo imaging, H&E staining, Masson trichrome staining, immunohistochemical staining, Western Blot, and qRT-PCR. The results showed that T-Exo significantly promoted wound healing by inhibiting inflammation, thereby further promoting angiogenesis and collagen formation in vivo. Moreover, the existence of Col scaffold in T-Exo/Col enabled T-Exo to achieve a certain sustained release effect. Finally, we further explored whether TSA exerts beneficial effects by inhibiting HDAC6 gene of BMSCs, but the results showed that knockdown of HDAC6 gene would cause oxidative stress damage to BMSCs, which means that TSA does not produce these beneficial effects by inhibiting HDAC6 gene. What molecular mechanisms TSA exerts beneficial effects through needs to be further elucidated in the future.

Extracellular vesicle-mediated drug delivery in breast cancer theranostics

Breast cancer (BC) continues to be a significant global challenge due to drug resistance and severe side effects. The increasing prevalence is alarming, requiring new therapeutic approaches to address these challenges. At this point, Extracellular vesicles (EVs), specifically small endosome-released nanometer-sized EVs (SEVs) or exosomes, have been explored by literature as potential theranostics. Therefore, this review aims to highlight the therapeutic potential of exosomes in BC, focusing on their advantages in drug delivery and their ability to mitigate metastasis. Following the review, we identified exosomes' potential in combination therapies, serving as miRNA carriers and contributing to improved anti-tumor effects. This is evident in clinical trials investigating exosomes in BC, which have shown their ability to boost chemotherapy efficacy by delivering drugs like paclitaxel (PTX) and doxorubicin (DOX). However, the translation of EVs into BC therapy is hindered by various challenges. These challenges include the heterogeneity of EVs, the selection of the appropriate parent cell, the loading procedures, and determining the optimal administration routes. Despite the promising therapeutic potential of EVs, these obstacles must be addressed to realize their benefits in BC treatment.

Research status and challenges of plant-derived exosome-like nanoparticles

In recent years, there has been an increasing number of related studies on exosomes. Most studies have focused on exosomes derived from mammals, confirming the important role that exosomes play in cell communication. Plants, as a natural ingredient, plant-derived exosomes have been confirmed to have similar structures and functions to mammalian-derived exosomes. Plant-derived exosome-like nanoparticles (PELNs) are lipid bilayer membrane nanovesicles containing bioactive constituents such as miRNA, mRNA, protein, and lipids obtained from plant cells, that can participate in intercellular communication and mediate transboundary communication, have high bioavailability and low immunogenicity, are relatively safe, and have been shown to play an important role in maintaining cell homeostasis and preventing, and treating a variety of diseases. In this review, we describe the biogenesis, isolation and purification methods, structural composition, stability, safety, function of PELNs and challenges. The functions of PELNs in anti-inflammatory, antioxidant, antitumor and drug delivery are mainly described, and the status of research on exosome nanoparticles of Chinese herbal medicines is outlined. Overall, we summarized the importance of PELNs and the latest research results in this field and provided a theoretical basis for the future research and clinical application of PELNs.

Endothelial cell-derived extracellular vesicles induce pro-angiogenic responses in mesenchymal stem cells

Angiogenesis is a central component of vital biological processes such as wound healing, tissue nourishment, and development. Therefore, angiogenic activities are precisely maintained with secreted factors such as angiopoietin-1 (Ang1), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF). As an element of intracellular communication, extracellular vesicles (EVs)-particularly EVs of vascular origin-could have key functions in maintaining angiogenesis. However, the functions of EVs in the control of angiogenesis have not been fully studied. In this study, human umbilical vein endothelial cell line (HUVEC)-derived small EVs (<200 nm; HU-sEVs) were investigated as a potential pro-angiogenic agent. Treating mesenchymal stem cells (MSCs) and mature HUVEC cells with HU-sEVs induced their tube formation under in vitro conditions and significantly increased the expression of angiogenesis-related genes, such as Ang1, VEGF, Flk-1 (VEGF receptor 2), Flt-1 (VEGF receptor 1), and vWF (von Willebrand Factor), in a dose-dependent manner. These results indicate that HU-sEVs take part in angiogenesis activities in physiological systems, and suggest endothelial EVs as a potential therapeutic candidate for the treatment of angiogenesis-related diseases.

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

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

Defining tropism and activity of natural and engineered extracellular vesicles

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

Methods, Mechanisms, and Application Prospects for Enhancing Extracellular Vesicle Uptake

Extracellular vesicles (EVs) are considered to be a new generation of bioinspired nanoscale drug delivery systems due to their low immunogenicity, natural functionality, and excellent biocompatibility. However, limitations such as low uptake efficiency, insufficient production, and inhomogeneous performance undermine their potential. To address these issues, numerous researchers have put forward various methods and applications for enhancing EV uptake in recent decades. In this review, we introduce various methods for the cellular uptake of EVs and summarize recent advances on the methods and mechanisms for enhancing EV uptake. In addition, we provide further understanding regarding enhancing EV uptake and put forward prospects and challenges for the development of EV-based therapy in the future.

Exploring the dynamic interplay between exosomes and the immune tumor microenvironment: implications for breast cancer progression and therapeutic strategies

Breast cancer continues to pose a substantial worldwide health concern, demanding a thorough comprehension of the complex interaction between cancerous cells and the immune system. Recent studies have shown the significant function of exosomes in facilitating intercellular communication and their participation in the advancement of cancer. Tumor-derived exosomes have been identified as significant regulators in the context of breast cancer, playing a crucial role in modulating immune cell activity and contributing to the advancement of the illness. This study aims to investigate the many effects of tumor-derived exosomes on immune cells in the setting of breast cancer. Specifically, we will examine their role in influencing immune cell polarization, facilitating immunological evasion, and modifying the tumor microenvironment. Furthermore, we explore the nascent domain of exosomes produced from immune cells and their prospective involvement in the prevention of breast cancer. This paper focuses on new research that emphasizes the immunomodulatory characteristics of exosomes produced from immune cells. It also explores the possibility of these exosomes as therapeutic agents or biomarkers for the early identification and prevention of breast cancer. The exploration of the reciprocal connections between exosomes formed from tumors and immune cells, together with the rising significance of exosomes derived from immune cells, presents a potential avenue for the advancement of novel approaches in the field of breast cancer therapy and prevention.

Exosomes: a promising avenue for cancer diagnosis beyond treatment

Exosomes, extracellular vesicles secreted by cells, have garnered significant attention in recent years for their remarkable therapeutic potential. These nanoscale carriers can be harnessed for the targeted delivery of therapeutic agents, such as pharmaceuticals, proteins, and nucleic acids, across biological barriers. This versatile attribute of exosomes is a promising modality for precision medicine applications, notably in the realm of cancer therapy. However, despite their substantial therapeutic potential, exosomes still confront challenges tied to standardization and scalability that impede their practice in clinical applications. Moreover, heterogeneity in isolation methodologies and limited cargo loading mechanisms pose obstacles to ensuring consistent outcomes, thereby constraining their therapeutic utility. In contrast, exosomes exhibit a distinct advantage in cancer diagnosis, as they harbor specific signatures reflective of the tumor's genetic and proteomic profile. This characteristic endows them with the potential to serve as valuable liquid biopsies for non-invasive and real-time monitoring, making possible early cancer detection for the development of personalized treatment strategies. In this review, we provide an extensive evaluation of the advancements in exosome research, critically examining their advantages and limitations in the context of cancer therapy and early diagnosis. Furthermore, we present a curated overview of the most recent technological innovations utilizing exosomes, with a focus on enhancing the efficacy of early cancer detection.

Functional Roles of Mesenchymal Stem Cell-derived Exosomes in Ischemic Stroke Treatment

Stroke is a life-threatening disease and one of the leading causes of death and physical disability worldwide. Currently, no drugs on the market promote neural recovery after stroke insult, and spontaneous remodeling processes are limited to induce recovery in the ischemic regions. Therefore, promoting a cell-based therapy has been needed to elevate the endogenous recovery process. Mesenchymal stem cells (MSCs) have been regarded as candidate cell sources for therapeutic purposes of ischemic stroke, and their therapeutic effects are mediated by exosomes. The microRNA cargo in these extracellular vesicles is mostly responsible for the positive effects. When it comes to the therapeutic viewpoint, MSCsderived exosomes could be a promising therapeutic strategy against ischemic stroke. The aim of this review is to discuss the current knowledge around the potential of MSCs-derived exosomes in the treatment of ischemic stroke.

Update on current and potential application of extracellular vesicles in kidney transplantation

Kidney transplantation (KT) is the best treatment for end-stage kidney disease. However, early diagnosis of graft injury remains challenging, mainly because of the lack of accurate and noninvasive diagnostic techniques. Improving graft outcomes is equally demanding, as is the development of innovative therapies. Many research efforts are focusing on extracellular vesicles, cellular particles free in each body fluid that have shown promising results as precise markers of damage and potential therapeutic targets in many diseases, including the renal field. In fact, through their receptors and cargo, they act in damage response and immune modulation. In transplantation, they may be used to determine organ quality and aging, the presence of delayed graft function, rejection, and many other transplant-related pathologies. Moreover, their low immunogenicity and safe profile make them ideal for drug delivery and the development of therapies to improve KT outcomes. In this review, we summarize current evidence about extracellular vesicles in KT, starting with their characteristics and major laboratory techniques for isolation and characterization. Then, we discuss their use as potential markers of damage and as therapeutic targets, discussing their promising use in clinical practice as a form of liquid biopsy.

Immune system roles in pathogenesis, prognosis, control, and treatment of Toxoplasma gondii infection

Toxoplasma gondii is the protozoan causative agent of toxoplasmosis in humans and warm-blooded animals. Recent studies have illustrated that the immune system plays a pivotal role in the pathogenesis of toxoplasmosis by triggering immune cytokines like IL-12, TNF-α, and IFN-γ and immune cells like DCs, Th1, and Th17. On the other hand, some immune components can serve as prognosis markers of toxoplasmosis. In healthy people, the disease is often asymptomatic, but immunocompromised people and newborns may suffer severe symptoms and complications. Therefore, the immune prognostic markers may provide tools to measure the disease progress and help patients to avoid further complications. Immunotherapies using monoclonal antibody, cytokines, immune cells, exosomes, novel vaccines, and anti-inflammatory molecules open new horizon for toxoplasmosis treatment. In this review article, we discussed the immunopathogenesis, prognosis, and immunotherapy of Toxoplasma gondii infection.

Applications and recent advances in transdermal drug delivery systems for the treatment of rheumatoid arthritis

Rheumatoid arthritis is a chronic, systemic autoimmune disease predominantly based on joint lesions with an extremely high disability and deformity rate. Several drugs have been used for the treatment of rheumatoid arthritis, but their use is limited by suboptimal bioavailability, serious adverse effects, and nonnegligible first-pass effects. In contrast, transdermal drug delivery systems (TDDSs) can avoid these drawbacks and improve patient compliance, making them a promising option for the treatment of rheumatoid arthritis (RA). Of course, TDDSs also face unique challenges, as the physiological barrier of the skin makes drug delivery somewhat limited. To overcome this barrier and maximize drug delivery efficiency, TDDSs have evolved in terms of the principle of transdermal facilitation and transdermal facilitation technology, and different generations of TDDSs have been derived, which have significantly improved transdermal efficiency and even achieved individualized controlled drug delivery. In this review, we summarize the different generations of transdermal drug delivery systems, the corresponding transdermal strategies, and their applications in the treatment of RA.

Extracellular vesicle-based drug delivery in cancer immunotherapy

Extracellular vesicles (EVs) are a group of nanoscale membrane-bound organelles including exosomes, microvesicles (MVs), membrane particles, and apoptotic bodies, which are released from almost all eukaryotic cells. Owing to their ingredients, EVs can be employed as biomarkers for human diseases. Interestingly, EVs show favorable features as candidates for targeted drug delivery and thus, they are suggested as ideal drug carriers as well as good vaccines for various human diseases including cancer. Among various drugs loaded in EVs for targeted drug delivery, immune checkpoint inhibitors (ICIs), including antibodies against programmed cell death-1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic-T-lymphocyte-associated protein 4 (CTLA-4), have attracted an increasing attention for cancer researchers and clinicians. Animal and clinical studies have shown combination of EVs and immunotherapy antibodies to improve the efficacy and reduce possible side effects in systemic administration of ICIs. In this review, we discuss the EVs and their significance in drug delivery with a focus on cancer immunotherapy agents.

Synthetic miR-26a mimics delivered by tumor exosomes repress hepatocellular carcinoma through downregulating lymphoid enhancer factor 1

BACKGROUND

The dysregulation of exosomal microRNAs plays an important role in the progression of hepatocarcinogenesis. In this study, we investigated the therapeutic potential of synthetic exosomal miR-26a against HCC cells and explored the feasibility of tumor-derived exosomes as drug delivery vehicles.

METHODS

Proliferation and migration assays were performed to examine the effects of miR-26a on HCC in vitro. The direct target gene of miR-26a was identified through miRecords analysis and target validation. The transferring efficiency and anti-HCC effect of exosomes with different origin were studied and the optimal miR-26a delivery method was established and verified in vitro and in vivo. In addition, the relationships between prognosis of HCC patients and miR-26a expression in HCC serum and exosomes were retrospectively analyzed.

RESULTS

Here, we found that tumor cell-derived exosomes were taken in preferentially by HCC cells and promoted HCC progression through Wnt pathway by low-density lipoprotein receptor-related protein 6 (LRP6). HCC cells with vacuolar protein sorting-associated protein 35 knocked down were adopted to generate engineered LRP6-exosomes. The engineered HCC-derived exosomes loading miR-26a inhibited HCC progression in vitro and in vivo effectively. Overexpression of miR-26a impaired the growth and migration of HCC by targeting lymphoid enhancer factor 1 (LEF1). Moreover, low expression of exosomal miR-26a was an independent prognostic factor for recurrence and survival in HCC patients.

CONCLUSIONS

Our findings suggested the exosomal miR-26a could serve as a non-invasive prognostic marker for HCC patients. Genetically modified tumor-derived exosomes showed preferable transfection efficiency but reduced Wnt activity, which provides a novel therapeutic strategy for HCC.

Advanced micro-/nanotechnologies for exosome encapsulation and targeting in regenerative medicine

Exosomes, a subset of vesicles generated from cell membranes, are crucial for cellular communication. Exosomes' innate qualities have been used in recent studies to create nanocarriers for various purposes, including medication delivery and immunotherapy. As a result, a wide range of approaches has been designed to utilize their non-immunogenic nature, drug-loading capacity, or targeting ability. In this study, we aimed to review the novel methods and approaches in exosome engineering for encapsulation and targeting in regenerative medicine. We have assessed and evaluated each method's efficacy, advantages, and disadvantages and discussed the results of related studies. Even though the therapeutic role of non-allogenic exosomes has been demonstrated in several studies, their application has certain limitations as these particles are neither fully specific to target tissue nor tissue retainable. Hence, there is a strong demand for developing more efficient encapsulation methods along with more accurate and precise targeting methods, such as 3D printing and magnetic nanoparticle loading in exosomes, respectively.