The tetraspanin CD63 regulates ESCRT-independent and -dependent endosomal sorting during melanogenesis

Integrated technologies for molecular profiling of genetic and modified biomarkers in extracellular vesicles

Extracellular vesicles (EVs) are nanoscale membrane vesicles actively released by cells into a variety of biofluids. EVs carry myriad molecular cargoes; these include classical genetic biomarkers inherited from the parent cells as well as EV modifications by other entities (e.g., small molecule drugs). Aided by these diverse cargoes, EVs enable long-distance intercellular communication and have been directly implicated in various disease pathologies. As such, EVs are being increasingly recognized as a source of valuable biomarkers for minimally-invasive disease diagnostics and prognostics. Despite the clinical potential, EV molecular profiling remains challenging, especially in clinical settings. Due to the nanoscale dimension of EVs as well as the abundance of contaminants in biofluids, conventional EV detection methods have limited resolution, require extensive sample processing and can lose rare biomarkers. To address these challenges, new micro- and nanotechnologies have been developed to discover EV biomarkers and empower clinical applications. In this review, we introduce EV biogenesis for different cargo incorporation, and discuss the use of various EV biomarkers for clinical applications. We also assess different chip-based integrated technologies developed to measure genetic and modified biomarkers in EVs. Finally, we highlight future opportunities in technology development to facilitate the clinical translation of various EV biomarkers.

Exosome Therapy in Stress Urinary Incontinence: A Comprehensive Literature Review

Stress urinary incontinence (SUI) is characterized by the involuntary leakage of urine when bladder pressure exceeds urethral closing pressure during routine activities such as physical exertion, coughing, exercise, or sneezing. SUI is the most prevalent form of urinary incontinence, with a reported prevalence ranging from 10% to 70%, and its incidence increases with age. As the global population continues to age, the prevalence and clinical significance of SUI are expected to rise accordingly. The pathophysiology of SUI is primarily driven by two mechanisms: urethral hypermobility, resulting from compromised supporting structures, and intrinsic urethral sphincter deficiency, characterized by the deterioration of urethral mucosa and muscle tone. Current treatment options for SUI include conservative management strategies, which heavily rely on patient adherence and are associated with high recurrence rates, and surgical interventions, such as sling procedures, which offer effective solutions but are costly and carry the risk of adverse side effects. These limitations highlight the urgent need for more effective and comprehensive treatment modalities. Exosomes, nano-sized (30-150 nm) extracellular vesicles secreted by nearly all cell types, have emerged as a novel therapeutic option due to their regenerative, anti-fibrotic, pro-angiogenic, anti-apoptotic, anti-inflammatory, and anti-hypoxic properties. These biological functions position exosomes as a promising alternative to conventional therapies for SUI. Exosome therapy has the potential to enhance tissue regeneration, restore urethral function, and repair nerve and muscle damage, thereby reducing symptom burden and improving patients' quality of life. Additionally, exosome-based treatments could offer a less invasive alternative to surgery, potentially decreasing the need for repeated interventions and minimizing complications associated with current procedures. In this literature review, we critically assess the current state of research on the potential use of exosomes in treating SUI, highlighting their therapeutic mechanisms and potential clinical benefits.

Tumor-derived exosomes as promising tools for cancer diagnosis and therapy

Mounting evidences indicated that cancer cell-derived exosomes (TDEs) contribute to cancer progression and metastasis by reshaping the tumor microenvironment (TME) and interfering immunity response. TDEs contain unique biomolecular cargo, consisting of protein, nucleic acid, and lipids. In recent years, TDEs have been used as potential disease therapeutics and diagnosis biomarkers and prime candidates as delivery tools for cancer treatment. In the present review, we firstly summarized TDEs biogenesis and characteristic. Also, the role of TDEs in cancer cell metastasis and invasiveness, drug resistance, and immunosuppression was mentioned via cell-cell communication. Additionally, we concluded the current strategies for TDE-based cancer therapy, including TDEs inhibition and clearance, usage as therapeutic drug delivery vector and cancer vaccines. Furthermore, combination therapy with engineered TDEs were summarized, such as radiotherapy, photodynamic therapy, photothermal therapy, and sonodynamic therapy. Consequently, the above opens up novel and interesting opportunities for cancer diagnosis and prognosis based on TDEs, which is prospective to accelerate the clinical translation of TDEs for cancer therapy.

Exosome-Based Sensor: A Landmark of the Precision Cancer Diagnostic Era

Extracellular vesicles are nanoscale vesicles released by a diversity of cells that mediate intercellular communication by transporting an array of biomolecules. They are gaining increasing attention in cancer research due to their ability to carry specific biomarkers. This characteristic makes them potentially useful for highly sensitive, noninvasive diagnostic procedures and more precise prognostic assessments. Consequently, EVs are emerging as a transformative tool in cancer treatment, facilitating early detection and personalized medicine. Despite significant progress, clinical implementation is hindered by challenges in EV isolation, purification, and characterization. However, developing advanced biosensor technologies offers promising solutions to these obstacles. This review highlights recent progress in biosensors for EV detection and analysis, focusing on various sensing modalities including optical, electrochemical, microfluidic, nanomechanical, and biological sensors. We also explore techniques for EV isolation, characterization, and analysis, such as electron microscopy, atomic force microscopy, nanoparticle tracking analysis, and single-particle analysis. Furthermore, the review critically assesses the challenges associated with EV detection and put forward future directions, aiming to usher in a cutting-edge era of precision medicine through advanced, sensor-based, noninvasive early cancer diagnosis by detecting EV-carried biomarkers.

Role of exosomes in pathogenesis, diagnosis, and treatment of diabetic nephropathy

Diabetic nephropathy (DN) is a serious microvascular complication that can progress to end-stage renal disease, with its prevalence and associated mortality increasing globally. However extensive research, the precise mechanisms underlying DN pathogenesis remain unclear, and the current treatment options for DN are limited to dialysis or renal replacement therapy, although several experimental approaches have shown potential, they remain investigational and lack clinical translation. Exosomes play a pivotal role in disease diagnosis and prognosis. Urinary exosomes, originating from various kidney cells, reflect the kidney's pathological condition and are involved in cell-to-cell communication through autocrine or paracrine signaling; therefore, they could contribute to the pathogenesis of DN and potential therapeutic approaches. Additionally, due to their diverse cargo, which depend on cellular origin and pathological state, exosomes may act as biomarkers for the early prediction of DN. This review presents a comprehensive overview of the latest findings on the role of exosomes in the diagnosis, pathogenesis, and treatment of DN.

Role of Exosome in Solid Cancer Progression and Its Potential Therapeutics in Cancer Treatment

BACKGROUND

Exosomes are extracellular vesicles ranging from 40 to 100 nm in diameter that mediate intercellular communication by transferring proteins, lipids, nucleic acids, and other metabolites. In the context of cancer, exosomes influence the tumor microenvironment by carrying regulatory RNAs such as miRNA, circRNA, and lncRNA. They originate from various cells, including adipocytes, fibroblasts, and hepatocellular carcinoma (HCC) cells, and can either promote or inhibit cancer progression through pathways like MAPK and PI3K-Akt.

AIM

This review aims to explore the role of exosomes in the progression of solid cancers, emphasizing their self-induced activation mechanisms and how they modulate tumor behavior.

METHODOLOGY

A comprehensive review of recent literature was conducted, focusing on studies that investigated the biological functions of exosomes in solid tumor progression, including their molecular cargo, cellular origin, and involvement in signaling pathways.

RESULTS

Findings from multiple studies indicate that cancer-derived exosomes contribute to tumor proliferation, metastasis, and therapy resistance by enhancing communication within the tumor microenvironment. These vesicles activate oncogenic pathways and can serve as biomarkers or therapeutic targets due to their role in disease modulation.

CONCLUSION

Exosomes play a pivotal role in solid cancer progression and offer significant potential in advancing our understanding of tumor biology. Their capacity to influence key signaling pathways and facilitate intercellular communication makes them promising candidates for novel diagnostic and therapeutic strategies.

Extracellular Vesicular Delta-Like Ligand 3 and Subtype Transcription Factors for Small Cell Lung Cancer Diagnosis

Small cell lung cancer (SCLC) is associated with high mortality and limited therapeutic options. There is increasing recognition that SCLC harbors molecular heterogeneity. Using a new liquid biopsy assay, it is demonstrated that SCLC subtypes, as determined by patient tumor tissue staining and cell lines, can be accurately identified by measuring the mRNA expression of subtype transcription factors (ASCL1, POU2F3, and NEUROD1) in circulating exosome-rich extracellular vesicles (Exo). Additionally, upregulation of Delta-like ligand 3 (DLL3) mRNA in Exo and its membrane protein (mProtein) in extracellular vesicles associated with tumor (tEV) may distinguish both limited- and extensive-stage SCLC patients from high-risk smokers, with AUC/ROC values of 0.836 and 0.839, respectively. By incorporating Exo-ASCL1 and Exo-POU2F3 mRNA expression with DLL3 Exo-mRNA/tEV-mProtein expression, the classifier enhances the AUC/ROC to 0.912 and 0.963 for limited- and extensive-stage SCLC patients, respectively.

Skin organoid transplantation promotes tissue repair with scarless in frostbite

Frostbite is the most common cold injury and is caused by both immediate cold-induced cell death and the gradual development of localized inflammation and tissue ischemia. Delayed healing of frostbite often leads to scar formation, which not only causes psychological distress but also tends to result in the development of secondary malignant tumors. Therefore, a rapid healing method for frostbite wounds is urgently needed. Herein, we used a mouse skin model of frostbite injury to evaluate the recovery process after frostbite. Moreover, single-cell transcriptomics was used to determine the patterns of changes in monocytes, macrophages, epidermal cells, and fibroblasts during frostbite. Most importantly, human-induced pluripotent stem cell (hiPSC)-derived skin organoids combined with gelatin-hydrogel were constructed for the treatment of frostbite. The results showed that skin organoid treatment significantly accelerated wound healing by reducing early inflammation after frostbite and increasing the proportions of epidermal stem cells. Moreover, in the later stage of wound healing, skin organoids reduced the overall proportions of fibroblasts, significantly reduced fibroblast-to-myofibroblast transition by regulating the integrin α5β1-FAK pathway, and remodeled the extracellular matrix (ECM) through degradation and reassembly mechanisms, facilitating the restoration of physiological ECM and reducing the abundance of ECM associated with abnormal scar formation. These results highlight the potential application of organoids for promoting the reversal of frostbite-related injury and the recovery of skin functions. This study provides a new therapeutic alternative for patients suffering from disfigurement and skin dysfunction caused by frostbite.

The role of plant-derived extracellular vesicles in ameliorating chronic diseases

Plant-derived extracellular vesicles (PDEVs) have been shown to have a promising role in treating chronic illnesses. Plants secrete these vesicles containing bioactive chemicals such as proteins, lipids, nucleic acids, and small metabolites. Because of their unique structure, PDEVs affect many biological processes, which makes them an ideal candidate for treating the complex pathophysiology of chronic diseases. Recent studies have shown that PDEVs have anti-inflammatory and antioxidant properties. Extracellular vesicles (EVs) possess diverse therapeutic potential, including anti-inflammatory, antioxidant, and regenerative properties. By regulating immune responses, scavenging free radicals, and promoting tissue repair, EVs can address various chronic diseases such as cardiovascular disorders, neurological conditions, skin diseases, and inflammatory ailments. In preclinical models, PDEVs have been demonstrated to improve heart function and minimize the size of myocardial infarctions. In neurodegenerative illnesses, they can pass through the blood-brain barrier and deliver neuroprotective medicines to the brain. Furthermore, PDEVs have shown promise in enhancing insulin sensitivity and lowering hyperglycemia in diabetic animals. In this review article, we attempt to explain the diverse therapeutic potential of PDEVs in ameliorating chronic diseases.

The endoplasmic reticulum as a cradle for virus and extracellular vesicle secretion

Extracellular vesicles (EVs) are small membranous carriers of protein, lipid, and nucleic acid cargoes and play a key role in intercellular communication. Recent work has revealed the previously under-recognized participation of endoplasmic reticulum (ER)-associated proteins (ERAPs) during EV secretion, using pathways reminiscent of viral replication and secretion. Here, we present highlights of the literature involving ER/ERAPs in EV biogenesis and propose mechanistic parallels with ERAPs exploited during viral infections. We propose that ERAPs play an active role in the release of EVs and viral particles, and we present views on whether viruses hijack or enhance pre-existing ERAP-dependent secretory machineries or whether they repurpose ERAPs to create new secretory pathways.

Stress-induced extracellular vesicles: insight into their altered proteomic composition and probable physiological role in cancer

EVs (extracellular vesicles) are phospholipid bilayer vesicles that can be released by both prokaryotic and eukaryotic cells in normal as well as altered physiological conditions. These vesicles also termed as signalosomes, possess a distinctive cargo comprising nucleic acids, proteins, lipids, and metabolites, enabling them to play a pivotal role in both local and long-distance intercellular communication. The composition, origin, and release of EVs can be influenced by different physiological conditions and a variety of stress factors, consequently affecting the contents carried within these vesicles. Therefore, identifying the modified contents of EVs can provide valuable insights into their functional role in stress-triggered communication. Particularly, this is important when EVs released from tumor microenvironment are investigated for their role in the development and dissemination of cancer. This review article emphasizes the importance of differential EV shedding and altered proteomic content in response to reduced oxygen concentration, altered levels of glucose and glutamine, pH variations, oxidative stress and Ca2+ ion concertation and it is subsequent effects on the behavior of recipient cells.

Tetraspanins affect membrane structures and the trafficking of molecular partners: what impact on extracellular vesicles?

Tetraspanins are a family of 33 proteins in mammals believed to play a crucial role in the compartmentalization of various associated proteins within cells and membranes. Recent studies have elucidated the structure of several tetraspanin members, revealing that while the four transmembrane domains typically adopt a cone-shaped configuration in crystals, other conformations are also possible. This cone-shaped structure may explain why tetraspanins are often enriched in curved and tubular cellular structures, such as microvilli, tunneling nanotubes, retraction fibers, or at the site of virus budding, and may contribute to the formation or maintenance of these structures. Tetraspanins have also been detected on midbody remnants and migrasomes, as well as on extracellular vesicles (EVs), for which CD9, CD81, and CD63 are widely used as markers. Although their impact on certain membrane structures and their ability to regulate the function and trafficking of associated proteins would suggest a potential role of tetraspanins either in EV formation or in regulating their protein composition, or both, efforts to characterize these roles have been complicated by conflicting results. In line with the interaction of certain tetraspanins with cholesterol, two recent studies have suggested that the presence or organization of oxysterols and cholesterol in EVs may be regulated by Tspan6 and CD63, respectively, paving the way for further research on the influence of tetraspanins on the lipid composition of EVs.

Extracellular vesicles in cancer progression: mechanisms and significance

Tumor recurrence, metastasis, clinical drug resistance, and immune evasion are critical events in cancer progression, characterized by significant spatiotemporal heterogeneity and plasticity. Intercellular communication between tumor cells and other cells within the tumor microenvironment plays a pivotal role in these processes. Extracellular vesicles (EVs), heterogeneous secretory messengers carrying bioactive molecules, facilitate this cell-to-cell communication, thereby dynamically influencing cancer progression. Deciphering the mechanisms of EV formation and regulatory pathways and identifying key networks and targets in tumor metastasis, drug resistance, and immune response mediated by EVs will provide new insights into the understanding of cancer progression patterns and offer innovative strategies for cancer diagnosis and therapy.

Intercellular communication via exosomes: A new paradigm in the pathophysiology of neurodegenerative disorders

Neurodegenerative disorders are one of the leading causes of death and disability and pose a great economic burden on healthcare systems. Generally, these neurodegenerative disorders have a progressive deterioration in neural function and structure, and deposition of misfolded proteins commonly occurs, such as amyloid-β in AD and α-synuclein in PD. However, there exists a special class of exosomes, which acts like a transmitter and enhances communication between cells. The present review discusses the significant role of exosomes in neurodegenerative diseases, with a focus on Amyotrophic lateral Sclerosis (ALS), AD, PD, and Huntington's disease (HD). In this review, the biogenesis of exosomes is discussed from multivesicular bodies and onwards to their release into the extracellular environment. The present review focuses on recent data concerning the possible use of modified exosomes as ND therapy. Indeed, future work is needed to explain the processes driving exosome biogenesis and cargo selection, while opening new routes by the use of exosome-based therapeutics in neurodegenerative disease diagnosis and treatment.

Extracellular vesicles in malaria: proteomics insights, in vitro and in vivo studies indicate the need for transitioning to natural human infections

Globally, an estimated 2.1 billion malaria cases and 11.7 million malaria deaths were averted in the period 2000-2022. Noticeably, despite effective control measurements, in 2022 there were an estimated 249 million malaria cases in 85 malaria-endemic countries and an increase of 5 million cases compared with 2021. Further understanding the biology, epidemiology, and pathogenesis of human malaria is therefore essential for achieving malaria elimination. Extracellular vesicles (EVs) are membrane-enclosed nanoparticles pivotal in intercellular communication and secreted by all cell types. Here, we will review what is currently known about EVs in malaria, from biogenesis and cargo to molecular insights of pathophysiology. Of relevance, a meta-analysis of proteomics cargo, and comparisons between in vitro and in vivo human studies revealed striking differences with those few studies reported from patients. Thus, indicating the need for rigor standardization of methodologies and for transitioning to human infections to elucidate their physiological role. We conclude with a focus on translational aspects in diagnosis and vaccine development and highlight key gaps in the knowledge of EVs in malaria research.

Extracellular vesicle-mediated bidirectional communication between the liver and other organs: mechanistic exploration and prospects for clinical applications

The liver, functioning as an endocrine organ, secretes a variety of substances that influence the activities of other body organs. Conversely, molecules generated by organs such as bone, the gut, and adipose tissue can also impact liver function. Accumulating evidence suggests bidirectional communication between the liver and other organs. However, research on how extracellular vesicles (EVs), which transport active molecular mediators, contribute to this interorgan communication is still in its nascent stages. EVs are capable of transporting functional molecules, including lipids, nucleic acids, and proteins, thereby affecting recipient cells across different organs at the biological level. This review examines the role of EVs in facilitating bidirectional communication between the liver and other organs such as bone, the cardiovascular system, the gut, the pancreas, the brain, the lungs, the kidneys, and adipose tissue. It explores their potential in disease treatment and highlights the challenges in understanding EV-mediated interorgan interactions. The contribution of mediator-carrying EVs to two-way communication between the liver and other organs remains an area of ongoing investigation. Future research will provide a more comprehensive theoretical foundation to clarify the precise mechanisms governing communication between the liver and other organs, pinpoint medical targets, and expand the application of EVs within the realm of precision medicine.

MicroRNAs: A Novel Approach for Monitoring Treatment Response in Major Depressive Disorder?

Major depressive disorder (MDD) is one of the most prevalent psychiatric disorders, with an increasing incidence each year and an important socioeconomic burden. Although new treatments are continuously being developed, there is no effective monitoring method to determine the suitability of treatment and ensure positive outcomes. Therefore, patients often struggle with ineffective antidepressants and their potential adverse effects, which halts any future progress in managing the disorder. Considering the potential of microRNAs (miRNAs) as biomarkers for various pathologies and the increasing evidence of the modulation of several genes involved in MDD, this minireview aimed to evaluate the literature data on the impact of miRNAs in MDD and their usefulness in monitoring treatment response. The correlations between antidepressants and the expression of several miRNAs support the existence of a common epigenetic mechanism of antidepressants and explain the epigenetic differences influencing treatment efficacy in MDD.

A small RNA effector conserved in herbivore insects suppresses host plant defense by cross-kingdom gene silencing

Herbivore insects deploy salivary effectors to manipulate the defense of their host plants. However, it remains unclear whether small RNAs from insects can function as effectors in regulating plant-insect interactions. Here, we report that a microRNA (miR29-b) found in the saliva of the phloem-feeding whitefly (Bemisia tabaci) can transfer into the host plant phloem during feeding and fine-tune the defense response of tobacco (Nicotiana tabacum) plants. We show that the salivary gland-enriched BtmiR29-b is produced by BtDicer 1 and released into tobacco cells via salivary exosomes. Once inside the plant cells, BtmiR29-b hijacks tobacco Argonaute 1 to silence the defense gene Bcl-2-associated athanogene 4 (NtBAG4). In tobacco, NtBAG4 acts as the positive regulator of phytohormones salicylic acid (SA) and jasmonic acid (JA), enhancing plant defense against whitefly attacks. Interestingly, we also found that miR29-b acts as a salivary effector in another Hemipteran insect, the aphid Myzus persicae, which inhibits tobacco resistance by degrading NtBAG4. Moreover, miR29-b is highly conserved in Hemiptera and across other insect orders such as Coleoptera, Hymenoptera, Orthoptera, and Blattaria. Computational analysis suggests that miR29-b may also target the evolutionarily conserved BAG4 gene in other plant species. We further provide evidence showing BtmiR29-b-mediated BAG4 cleavage and defense suppression in tomato (Solanum lycopersicum). Taken together, our work reveals that a conserved miR29-b effector from insects fine-tunes plant SA- and JA-mediated defense by cross-kingdom silencing of the host plant BAG4 gene, providing new insight into the defense and counter-defense mechanisms between herbivores and their host plants.

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.

Breaking barriers in targeted Therapy: Advancing exosome Isolation, Engineering, and imaging

Exosomes have emerged as promising tools for targeted drug delivery in biomedical applications and medicine. This review delves into the scientific advancements, challenges, and future prospects specifically associated with these technologies. In this work, we trace the research milestones that led to the discovery and characterization of exosomes and extracellular vesicles, and discuss strategies for optimizing the synthetic yield and the loading of these particles with various therapeutics. In addition, we report the current major issues affecting the field and hampering the clinical translation of these technologies. Highlighting the pivotal role of imaging techniques, we explore how they drive exosome therapy and development by offering insights into biodistribution and cellular trafficking dynamics. Methodologies for vesicle isolation, characterization, loading, and delivery mechanisms are thoroughly examined, alongside strategies aimed at enhancing their therapeutic efficacy. Special emphasis was dedicated to their therapeutic properties, particularly to their ability to deliver biologics into the cytoplasm. Furthermore, we delve into the intricate balance between surface modifications and targeting properties including also transgenic methods aimed at their functionalization and visualization within biological systems. This review underscores the transformative potential of these carriers in targeted drug delivery and identifies crucial areas for further research and clinical translation.

Tetraspanin CD9 alters cellular trafficking and endocytosis of tetraspanin CD63, affecting CD63 packaging into small extracellular vesicles

Small extracellular vesicles (sEVs) are particles secreted from cells that play vital roles both in normal physiology and in human disease. sEVs are highly enriched in tetraspanin proteins, such as CD9 and CD63, and contain tetraspanin-enriched membrane microdomains involved in loading of sEVs with macromolecule cargoes and in sEV biogenesis. However, the precise roles of individual tetraspanins in sEV biogenesis and cargo loading remain poorly understood. Here, we report that CD9 negatively regulated CD63 trafficking to tetraspanin-enriched microdomains and its subsequent packaging into sEVs, whereas CD63 had no discernable effect on CD9 localization or packaging. Using super resolution microscopy of individual vesicles, we showed that CD9 governs the fraction of sEVs that are loaded with CD63. Interestingly, CD9-dependent suppression of CD63 packaging was rescued by pharmacological blockade of endocytosis. Together, our data support a model where CD9 contributes to the regulation and secretion of CD63 in an endocytosis-dependent manner to reprogram the contents of sEVs and tetraspanin-enriched microdomains.

A cautionary note on the potential pitfalls of using N-terminal truncated CD63 to label small extracellular vesicles

Small extracellular vesicles (sEV) are nanosized vesicles that facilitate intracellular communication. A significant research obstacle is the isolation of sEV devoid of non-sEV contaminants. Immunoaffinity capture with sEV-specific antibodies is an attractive approach to purifying sEV, but it risks disrupting the vesicles during antibody dissociation. Furthermore, immunoaffinity capture may require the modification of EV-specific proteins for the incorporation of tags on the EV surface, with unknown implications on EV production and function. The aim of this study was to investigate whether a previously reported CD63 truncation is efficient for the incorporation of small tags on the extravesicular surface. We therefore conjugated ALFA-tag to N-terminal-truncated CD63, and included nanoluciferase at the C-terminus, for luminescent tracing of the sEV. Full-length CD63-nanoluciferase was used as a control. Plasmid constructs expressing these proteins were transfected into HEK293 cells. In contrast to a previous report, the N-terminal truncation of CD63 impaired its membrane localisation and reduced the yield of EVs. Further investigation revealed that some of the tagged CD63 was co-localized with aggresomes and was preferentially secreted from the cells as soluble protein rather than being associated with sEV. These results demonstrate that CD63 truncation can impair its function and EV yield, potentially generating misleading results.

Bioengineered extracellular vesicles: The path to precision medicine in liver diseases

Extracellular vesicles (EVs) are membrane-bound entities secreted by each cell, categorized as, exosomes, microvesicles or apoptotic bodies based on their size and biogenesis. They serve as promising vectors for drug delivery due to their capacity to carry diverse molecular signatures reflective of their cell of origin. EV research has significantly advanced since their serendipitous discovery, with recent studies focusing on their roles in various diseases and their potential for targeted therapy. In liver diseases, EVs are particularly promising for precision medicine, providing diagnostic and therapeutic potential in conditions such as metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, hepatocellular carcinoma, alcoholic liver disease, liver fibrosis, and acute liver failure. Despite challenges in isolation and characterization, engineered EVs have shown efficacy in delivering therapeutic agents with improved targeting and reduced side effects. As research progresses, EVs hold great promise to revolutionize precision medicine in liver diseases, offering targeted, efficient, and versatile therapeutic options. In this review, we summarize various techniques for loading EVs with therapeutic cargo including both passive and active methods, and the potential of bioengineered EVs loaded with various molecules, such as miRNAs, proteins, and anti-inflammatory drugs in ameliorating clinical pathologies of liver diseases.

Hypoxia regulates small extracellular vesicle biogenesis and cargo sorting through HIF-1α/HRS signaling pathway in head and neck squamous cell carcinoma

Small extracellular vesicles (sEVs) act as crucial messengers that transmit biological signals in hypoxic tumor microenvironment (TME), significantly impacting cancer progression. However, the precise mechanism by which hypoxia influences sEV biogenesis remains poorly understood. In this study, we observed increased sEV secretion and alterations in cargo composition in head and neck squamous cell carcinoma (HNSCC) cells under hypoxic conditions. We found that hepatocyte growth factor-regulated tyrosine kinase substrate (HRS), a key component of the endosomal sorting complexes required for transport (ESCRT), was upregulated during hypoxia. This upregulation activated the endosomal system and reduced degradation of multivesicular bodies (MVBs). HRS depletion altered the packaging of protein cargoes such as mitochondria-related proteins into sEVs under hypoxia, and these cargoes promoted a pro-tumorigenic phenotype of macrophages. Importantly, we demonstrated that HRS is transcriptionally activated by hypoxia inducible factor-1α (HIF-1α). Spatial transcriptomics and immunohistochemistry revealed a positive correlation between HRS and HIF-1α. These findings establish a link between the hypoxic response, sEV biogenesis, and cargo packaging, enhancing our understanding of how the hypoxic TME influences sEV biogenesis in HNSCC cells.

Molecular mechanisms and pathological implications of unconventional protein secretion in human disease: from cellular stress to therapeutic targeting

Unconventional protein secretion (UcPS) encompasses diverse non-canonical cellular export mechanisms that operate independently of the classical secretory pathway, representing a crucial cellular response to various physiological and pathological conditions. This comprehensive review synthesizes current understanding of UcPS mechanisms, particularly focusing on their roles in disease pathogenesis and progression. Recent advances in proteomics and cellular biology have revealed that UcPS facilitates the secretion of various biomedically significant proteins, including inflammatory mediators, growth factors, and disease-associated proteins, through multiple pathways such as membrane translocation, secretory lysosomes, and membrane-bound organelles. Notably, dysregulation of UcPS mechanisms has been implicated in various pathological conditions, including chronic inflammation, neurodegenerative disorders, and malignant transformation. We critically evaluate the molecular machinery governing UcPS, its regulation under cellular stress, and its contribution to disease mechanisms. Furthermore, we examine emerging therapeutic strategies targeting UcPS pathways, highlighting both opportunities and challenges in developing novel interventional approaches.

Acidity and hypoxia of tumor microenvironment, a positive interplay in extracellular vesicle release by tumor cells

The complex and continuously evolving features of the tumor microenvironment, varying between tumor histotypes, are characterized by the presence of host cells and tumor cells embedded in a milieu shaped by hypoxia and low pH, resulting from the frequent imbalance between vascularity and tumor cell proliferation. These microenvironmental metabolic stressors play a crucial role in remodeling host cells and tumor cells, contributing to the stimulation of cancer cell heterogeneity, clonal evolution, and multidrug resistance, ultimately leading to progression and metastasis. The extracellular vesicles (EVs), membrane-enclosed structures released into the extracellular milieu by tumor/host cells, are now recognized as critical drivers in the complex intercellular communication between tumor cells and the local cellular components in a hypoxic/acidic microenvironment. Understanding the intricate molecular mechanisms governing the interactions between tumor and host cells within a hypoxic and acidic microenvironment, triggered by the release of EVs, could pave the way for innovative strategies to disrupt the complex interplay of cancer cells with their microenvironment. This approach may contribute to the development of an efficient and safe therapeutic strategy to combat cancer progression. Therefore, we review the major findings on the release of EVs in a hypoxic/acidic tumor microenvironment to appreciate their role in tumor progression toward metastatic disease.

Stem cell-derived exosome delivery systems for treating atherosclerosis: The new frontier of stem cell therapy

Cardiovascular diseases (CVDs) are a leading cause of mortality worldwide. As a chronic inflammatory disease with a complicated pathophysiology marked by abnormal lipid metabolism and arterial plaque formation, atherosclerosis is a major contributor to CVDs and can induce abrupt cardiac events. The discovery of exosomes' role in intercellular communication has sparked a great deal of interest in them recently. Exosomes are involved in strategic phases of the onset and development of atherosclerosis because they have been identified to control pathophysiologic pathways including inflammation, angiogenesis, or senescence. This review investigates the potential role of stem cell-derived exosomes in atherosclerosis management. We briefly introduced atherosclerosis and stem cell therapy including stem cell-derived exosomes. The biogenesis of exosomes along with their secretion and isolation have been elaborated. The design engineering of exosomes has been summarized to present how drug loading and surface modification with targeting ligands can improve the therapeutic and targeting capacity of exosomes, demonstrating atheroprotective action. Moreover, the mechanism of action (endothelial dysfunction, reduction of dyslipidemia, macrophage polarization, vascular calcification, and angiogenesis) of drug-loaded exosomes to treat atherosclerosis has been discussed in detail. In the end, a comparative and balanced viewpoint has been given regarding the current challenges and potential solutions to advance exosome engineering for cardiovascular therapeutic applications.

Prominosomes - a particular class of extracellular vesicles containing prominin-1/CD133?

Extracellular membrane vesicles (EVs) offer promising values in various medical fields, e.g., as biomarkers in liquid biopsies or as native (or bioengineered) biological nanocarriers in tissue engineering, regenerative medicine and cancer therapy. Based on their cellular origin EVs can vary considerably in composition and diameter. Cell biological studies on mammalian prominin-1, a cholesterol-binding membrane glycoprotein, have helped to reveal new donor membranes as sources of EVs. For instance, small EVs can originate from microvilli and primary cilia, while large EVs might be produced by transient structures such as retracting cellular extremities of cancer cells during the mitotic rounding process, and the midbody at the end of cytokinesis. Here, we will highlight the various subcellular origins of prominin-1+ EVs, also called prominosomes, and the potential mechanism(s) regulating their formation. We will further discuss the molecular and cellular characteristics of prominin-1, notably those that have a direct effect on the release of prominin-1+ EVs, a process that might be directly implicated in donor cell reprogramming of stem and cancer stem cells. Prominin-1+ EVs also mediate intercellular communication during embryonic development and adult homeostasis in healthy individuals, while disseminating biological information during diseases.

Investigating the role of exosomal long non-coding RNAs in drug resistance within female reproductive system cancers

Exosomes, as key mediators of intercellular communication, have been increasingly recognized for their role in the oncogenic processes, particularly in facilitating drug resistance. This article delves into the emerging evidence linking exosomal lncRNAs to the modulation of drug resistance mechanisms in cancers such as ovarian, cervical, and endometrial cancer. It synthesizes current research findings on how these lncRNAs influence cancer cell survival, tumor microenvironment, and chemotherapy efficacy. Additionally, the review highlights potential therapeutic strategies targeting exosomal lncRNAs, proposing a new frontier in overcoming drug resistance. By mapping the interface of exosomal lncRNAs and drug resistance, this article aims to provide a comprehensive understanding that could pave the way for innovative treatments and improved patient outcomes in female reproductive system cancers.

Keratin intermediate filaments mechanically position melanin pigments for genome photoprotection

Melanin pigments block genotoxic agents by positioning on the sun-exposed side of human skin keratinocytes' nucleus. How this position is regulated and its role in genome photoprotection remains unknown. By developing a model of human keratinocytes internalizing extracellular melanin into pigment organelles, we show that keratin 5/14 intermediate filaments mechanically control the 3D perinuclear position of pigments, shielding DNA from photodamage. Imaging and microrheology in human disease-related model identify structural keratin cages surrounding pigment organelles to stiffen their microenvironment and maintain their 3D position. Optimum pigment spatialization is required for DNA photoprotection and rely on the interplay between intermediate filaments and microtubules bridged by plectin cytolinkers. Thus, the mechanically-driven proximity of pigment organelles to the nucleus is a key photoprotective parameter. Uncovering how human skin counteracts solar radiation by positioning the melanin microparasol next to the genome anticipates that dynamic spatialization of organelles is a physiological UV stress response.

Heterogeneity of late endosome/lysosomes shown by multiplexed DNA-PAINT imaging

Late endosomes/lysosomes (LELs) are crucial for numerous physiological processes and their dysfunction is linked to many diseases. Proteomic analyses have identified hundreds of LEL proteins; however, whether these proteins are uniformly present on each LEL, or if there are cell-type-dependent LEL subpopulations with unique protein compositions is unclear. We employed quantitative, multiplexed DNA-PAINT super-resolution imaging to examine the distribution of seven key LEL proteins (LAMP1, LAMP2, CD63, Cathepsin D, TMEM192, NPC1, and LAMTOR4). While LAMP1, LAMP2, and Cathepsin D were abundant across LELs, marking a common population, most analyzed proteins were associated with specific LEL subpopulations. Our multiplexed imaging approach identified up to eight different LEL subpopulations based on their unique membrane protein composition. Additionally, our analysis of the spatial relationships between these subpopulations and mitochondria revealed a cell-type-specific tendency for NPC1-positive LELs to be closely positioned to mitochondria. Our approach will be broadly applicable to determining organelle heterogeneity with single organelle resolution in many biological contexts.

Extracellular Vesicles in the Aging Male Reproductive System: Progresses and Perspectives

Extracellular vesicles (EVs) serve as crucial mediators of intercellular communication in spermatogenesis, steroidogenesis, and age-related pathophysiological processes within the male reproductive system. These EVs exhibit promising prospects for disease diagnosis and therapeutic administration. This review explores the impact of advanced paternal age on male fertility and testosterone decline, shedding light on the underlying mechanisms. It highlights the decline in semen quality, DNA damage, and alterations in sperm miRNA profiles associated with aging. The interplay between oxidative stress and antioxidants crucially regulates male reproductive aging. Currently, most studies focus on Sertoli cell-derived EVs, while understanding of Leydig cell-derived vesicles remains limited. Multi-omics integration will enhance the understanding of male reproductive aging and guide personalized interventions, revealing potential biomarkers and targets in the future.

Extracellular vesicles as emerging players in glaucoma: Mechanisms, biomarkers, and therapeutic targets

In recent years, extracellular vesicles (EVs) have attracted significant scientific interest due to their widespread distribution, their potential as disease biomarkers, and their promising applications in therapy. Encapsulated by lipid bilayers these nanovesicles include small extracellular vesicles (sEV) (30-150 nm), microvesicles (100-1000 nm), and apoptotic bodies (100-5000 nm) and are essential for cellular communication, immune responses, biomolecular transport, and physiological regulation. As they reflect the condition and functionality of their originating cells, EVs play critical roles in numerous physiological processes and diseases. Therefore, EVs offer valuable opportunities for uncovering disease mechanisms, enhancing drug delivery systems, and identifying novel biomarkers. In the context of glaucoma, a leading cause of irreversible blindness, the specific roles of EVs are still largely unexplored. This review examines the emerging role of EVs in the pathogenesis of glaucoma, with a focus on their potential as diagnostic biomarkers and therapeutic agents. Through a thorough analysis of current literature, we summarize key advancements in EV research and identify areas where further investigation is needed to fully understand their function in glaucoma.

Distinct molecular properties and functions of small EV subpopulations isolated from human umbilical cord MSCs using tangential flow filtration combined with size exclusion chromatography

As functional derivatives of mesenchymal stem cells (MSCs), small extracellular vesicles (sEVs) have garnered significant attention and application in regenerative medicine. However, the technical limitations for large-scale isolation of sEVs and their heterogeneous nature have added complexity to their applications. It remains unclear if the heterogeneous sEVs represent different aspects of MSCs functions. Here, we provide a method for the large-scale production of sEVs subpopulations derived from human umbilical cord mesenchymal stem cells (HucMSCs), utilizing tangential flow filtration combined with size exclusion chromatography. The resulting subpopulations, S1-sEVs and S2-sEVs, exhibited stable variations in size, membrane-marked proteins, and carrying cargos, thereby displaying distinct functions both in vitro and in animal disease models. S1-sEVs, that highly expressed CD9, HRS and GPC1, demonstrated a greater immunomodulatory impact, while S2-sEVs with enriched expression of CD63 and FLOT1/2 possessed enhanced capacities in promoting cell proliferation and angiogenesis. These discrepancies are attributed to the specific proteins and miRNAs they contain. Further investigation revealed that the two distinct sEVs subpopulations corresponded to different biological processes: the ESCRT pathway (S1-sEVs) and the ESCRT-independent pathway represented by lipid rafts (S2-sEVs). Therefore, we propose the potential for large-scale isolation and purification of sEVs subpopulations from HucMSCs with distinct functions. This approach may provide advantages for targeted therapeutic interventions in various MSC indications.

Presenilins as hub proteins controlling the endocytic and autophagic pathways and small extracellular vesicle secretion

Emerging evidence indicates that autophagy is tightly connected to the endocytic pathway. Here, we questioned the role of presenilins (PSENs 1 and 2), previously shown to be involved in autophagy regulation, in the secretion of small endocytic-originating extracellular vesicles known as exosomes. Indeed, while wild-type cells responded to stimuli promoting both multivesicular endosome (MVE) formation and secretion of small extracellular vesicles (sEVs) enriched in canonical exosomal proteins, PSEN-deficient cells were almost unaffected to these stimuli. Moreover, in PSEN-deficient cells, the re-expression of either PSEN1 or the functional active PSEN1delta9 mutant led to a rescue of most sEV secretion, while the deletion of PSEN1 alone almost fully phenocopied total PSEN invalidation. We found that the lack of sEV secretion in PSEN-deficient cells was also due to overactivated autophagy promoting MVEs to degradation rather than to plasma membrane fusion. Hence, in these cells, the autophagic blocker bafilomycin A1 (BafA1) not only increased the intracellular levels of the MVE protein CD63, but also turned on sEV secretion by stimulating autophagy-dependent unconventional secretion. In that case, sEVs arised from amphisomes and were enriched in both canonical exosomal proteins and lysosomal-autophagy-associated cargo. Altogether, we here demonstrate that PSENs, and particularly PSEN1, act as hub proteins controlling the balance between endosomal/autophagic degradation and secretion. More generally, our findings strengthen the view of a strong interconnection between the endocytic and autophagic pathways and their complementary roles in sEV secretion.

Bubble Ticket Trip: Exploring the Mechanism of miRNA Sorting into Exosomes and Maintaining the Stability of Tumor Microenvironment

Exosomes are vesicles ranging from 30 to 100 nanometers in size that show great potential as carriers for therapeutic uses and drug delivery. Enriching a specific set of miRNAs in exosomes emphasizes the existence of particular sorting mechanisms that manage the targeted cargo packaging. The molecular mechanism for miRNA sorting has not been understood. It is crucial to understand the mechanism of exosome encapsulation to develop its therapeutic potential. In this review, we will explore the particular processes through which exosomes naturally encapsulate miRNA, as well as discuss the effect on tumors after encapsulation of miRNAs. We also summarize the effects of targeted drug delivery using genetic engineering and chemical methods to modify exosome-encapsulated miRNA. Finally, gaining insight into how exosome cargo is sorted could be applied in clinical settings for precise drug delivery and to hinder the progression of diseases.

Osseointegration-Related Exosomes for Surface Functionalization of Titanium Implants

Despite that the clinical application of titanium-based implants has achieved great success, patients' own diseases and/or unhealthy lifestyle habits often lead to implant failure. Many studies have been carried out to modify titanium implants to promote osseointegration and implant success. Recent studies showed that exosomes, proactively secreted extracellular vesicles by mammalian cells, could selectively target and modulate the functions of recipient cells such as macrophages, nerve cells, endothelial cells, and bone marrow mesenchymal stem cells that are closely involved in implant osseointegration. Accordingly, using exosomes to functionalize titanium implants has been deemed as a novel and effective way to improve their osseointegration ability. Herein, recent advances pertaining to surface functionalization of titanium implants with exosomes are analyzed and discussed, with focus on the role of exosomes in regulating the functions of osseointegration-related cells, and their immobilization strategies as well as resultant impact on osseointegration ability.

EV-Elute: A universal platform for the enrichment of functional surface marker-defined extracellular vesicle subpopulations

Intercellular communication via extracellular vesicles (EVs) has been identified as a vital component of a steadily expanding number of physiological and pathological processes. To accommodate these roles, EVs have highly heterogeneous molecular compositions. Given that surface molecules on EVs determine their interactions with their environment, EV functionality likely differs between subpopulations with varying surface compositions. However, it has been technically challenging to examine such functional heterogeneity due to a lack of non-destructive methods to separate EV subpopulations based on their surface markers. Here, we used the Design-of-Experiments (DoE) methodology to optimize a protocol, which we name 'EV-Elute', to elute intact EVs from commercially available Protein G-coated magnetic beads. We captured EVs from various cell types on these beads using antibodies against CD9, CD63, CD81 and a custom-made protein binding phosphatidylserine (PS). When applying EV-Elute, over 70% of bound EVs could be recovered from the beads in a pH- and incubation-time-dependent fashion. EV subpopulations showed intact integrity by electron microscopy and Proteinase K protection assays and showed uptake patterns similar to whole EV isolates in co-cultures of peripheral blood mononuclear cells (PBMCs) and endothelial cells. However, in Cas9/sgRNA delivery assays, CD63+ EVs showed a lower capacity to functionally deliver cargo as compared to CD9+, CD81+ and PS+ EVs. Taken together, we developed a novel, easy-to-use platform to isolate and functionally compare surface marker-defined EV subpopulations. This platform does not require specialized equipment or reagents and is universally applicable to any capturing antibody and EV source. Hence, EV-Elute can open new opportunities to study EV functionality at the subpopulation level.

Extracellular vesicles and nanoparticles at a glance

Cells can communicate with neighboring and more distant cells by secretion of extracellular vesicles (EVs). EVs are lipid bilayer membrane-bound structures that can be packaged with proteins, nucleic acids and lipids that mediate cell-cell signaling. EVs are increasingly recognized to play numerous important roles in both normal physiological processes and pathological conditions. Steady progress in the field has uncovered a great diversity and heterogeneity of distinct vesicle types that appear to be secreted from most, if not all, cell types. Recently, it has become apparent that cells also release non-vesicular extracellular nanoparticles (NVEPs), including the newly discovered exomeres and supermeres. In this Cell Science at a Glance article and the accompanying poster, we provide an overview of the diversity of EVs and nanoparticles that are released from cells into the extracellular space, highlighting recent advances in the field.

miRNA packaging into small extracellular vesicles and implications in pain

Extracellular vesicles (EVs) are a heterogenous group of lipid bilayer bound particles naturally released by cells. These vesicles are classified based on their biogenesis pathway and diameter. The overlap in size of exosomes generated from the exosomal pathway and macrovesicles that are pinched off from the surface of the plasma membrane makes it challenging to isolate pure populations. Hence, isolated vesicles that are less than 200 nm are called small extracellular vesicles (sEVs). Extracellular vesicles transport a variety of cargo molecules, and multiple mechanisms govern the packaging of cargo into sEVs. Here, we discuss the current understanding of how miRNAs are targeted into sEVs, including the role of RNA binding proteins and EXOmotif sequences present in miRNAs in sEV loading. Several studies in human pain disorders and rodent models of pain have reported alterations in sEV cargo, including miRNAs. The sorting mechanisms and target regulation of miR-939, a miRNA altered in individuals with complex regional pain syndrome, is discussed in the context of inflammation. We also provide a broad overview of the therapeutic strategies being pursued to utilize sEVs in the clinic and the work needed to further our understanding of EVs to successfully deploy sEVs as a pain therapeutic.

Impact of UPF2 on the levels of CD81 on extracellular vesicles

Extracellular vesicles (EVs) are involved in cell-to-cell communication. Following uptake, EV cargo molecules, including DNA, RNA, lipids, and proteins, influence gene expression and molecular signaling in recipient cells. Although various studies have identified disease-specific EV molecules, further research into their biogenesis and secretion mechanisms is needed for clinical application. Here, we investigated the role of UPF2 in regulating the biogenesis and components of EVs. Notably, UPF2 promoted the expression of CD81, a membrane protein marker of EVs, as UPF2 silencing decreased CD81 levels in EVs, both inside the cell and secreted. In contrast, the expression levels of CD63 increased, without altering the size or numbers of EVs. In addition, reducing UPF2 levels did not affect the total number of EVs but lowered production of CD81-positive EVs and reduced the efficiency of uptake by recipient cells. Collectively, our findings uncover a novel function for UPF2 in regulating the production of CD81 and changing EV properties.

Molecular Targeting of Ischemic Stroke: The Promise of Naïve and Engineered Extracellular Vesicles

Ischemic stroke (IS) remains a leading cause of mortality and long-term disability worldwide, with limited therapeutic options available. Despite the success of early interventions, such as tissue-type plasminogen activator administration and mechanical thrombectomy, many patients continue to experience persistent neurological deficits. The pathophysiology of IS is multifaceted, encompassing excitotoxicity, oxidative and nitrosative stress, inflammation, and blood-brain barrier disruption, all of which contribute to neural cell death, further complicating the treatment of IS. Recently, extracellular vesicles (EVs) secreted naturally by various cell types have emerged as promising therapeutic agents because of their ability to facilitate selective cell-to-cell communication, neuroprotection, and tissue regeneration. Furthermore, engineered EVs, designed to enhance targeted delivery and therapeutic cargo, hold the potential to improve their therapeutic benefits by mitigating neuronal damage and promoting neurogenesis and angiogenesis. This review summarizes the characteristics of EVs, the molecular mechanisms underlying IS pathophysiology, and the emerging role of EVs in IS treatment at the molecular level. This review also explores the recent advancements in EV engineering, including the incorporation of specific proteins, RNAs, or pharmacological agents into EVs to enhance their therapeutic efficacy.

Challenging the conventional wisdom: Re-evaluating Smpd3's role in extracellular vesicle biogenesis

Extracellular vesicles (EVs) are pivotal in intercellular communication, impacting diverse physiological and pathological processes. Current in vitro EV biogenesis studies often utilize pharmacological inhibitors, inducing off-target effects and overlooking cell-specific production nuances. Addressing these limitations, we utilized CRISPR/Cas9 to generate heterozygous full-body and conditional sphingomyelin phosphodiesterase 3 (Smpd3) knockout (KO) transgenic mice. Smpd3, also known as neutral sphingomyelinase 2 (nSMase2), triggers membrane curvature through sphingomyelin hydrolysis to ceramide, thereby influencing exosome release. Intriguingly, Smpd3 deficiency demonstrated no impact on EV release both in vitro and in vivo, underscoring its potential cell-type-specific role in EV biogenesis. Notably, bone marrow derived macrophages (BMDMs) did exhibit reduced EV release upon Alix deletion. Our findings open avenues for subsequent inquiries, enriching our knowledge of EV biogenesis and illuminating intercellular communication in health and disease.

Extracellular Vesicles as Potential Biomarkers in Addictive Disorders

Small extracellular vesicles (sEVs) and their role in mental and addictive disorders are extremely promising research areas. Because of their small size, sEVs can pass through the blood-brain barrier. The membrane of sEVs contain proteins that protect them against destruction by the organism's immune system. Due to these properties, sEVs circulating in the blood can be used as potential biomarkers of processes occurring in the brain. Exposure to psychoactive substances in vitro and in vivo affects sEV biogenesis and significantly alters the amount of sEVs and chemical composition of their cargo. Based on the published reports, sEVs carry numerous potential biomarkers of addictive pathologies, although the diagnostic significance of these markers still has to be evaluated. A large body of evidence indicates that psychoactive substances influence Rab family GTPases, Toll-like receptors, complement system components, and cytokines. In some studies, the effect of psychoactive substances on sEVs was found to be sex-dependent. It has become commonly accepted that sEVs are involved in the regulation of neuroinflammation and interaction between glial cells and neurons, as well as between peripheral cells and cells of the central nervous system. Here, we formulated a hypothesis on the existence of two mechanisms/stages involved in the effect of psychoactive substances on sEVs: the "fast" mechanism that provides neuroplasticity, and the "slow" one, resulting from the impaired biogenesis of sEVs and formation of aberrant vesicles.

Unlocking the potential of extracellular vesicle circRNAs in breast cancer: From molecular mechanisms to therapeutic horizons

Breast cancer remains the leading cause of cancer-related morbidity and mortality among women worldwide, underscoring the urgent need for novel diagnostic and therapeutic strategies. This review explores the emerging roles of circular RNAs (circRNAs) within extracellular vesicles (exosomes) in breast cancer. circRNAs, known for their stability and tissue-specific expression, are aberrantly expressed in breast cancer and regulate critical cellular processes such as proliferation, migration, and apoptosis, positioning them as promising biomarkers. Exosomes facilitate intercellular communication by delivering circRNAs, reflecting the physiological and pathological state of their source cells. This review highlights the multifaceted roles of exosomal circRNAs in promoting tumor growth, metastasis, and drug resistance through their modulation of tumor metabolism, the tumor microenvironment, and immune responses. In particular, we emphasize their contributions to chemotherapy resistance and their potential as both diagnostic markers and therapeutic targets. By synthesizing current research, this review provides novel insights into the clinical applications of exosomal circRNAs, offering a foundation for future studies aimed at improving breast cancer management through non-invasive diagnostics and targeted therapies.

The Therapeutic Potential of Exosomes vs. Matrix-Bound Nanovesicles from Human Umbilical Cord Mesenchymal Stromal Cells in Osteoarthritis Treatment

Osteoarthritis (OA) is a degenerative joint disease with limited therapeutic options, where inflammation plays a critical role in disease progression. Extracellular vesicles (EV) derived from mesenchymal stromal cells (MSC) have shown potential as a therapeutic approach for OA by modulating inflammation and alleviating degenerative processes in the joint. This study evaluated the therapeutic effects for the treatment of OA of two types of EV-exosomes and matrix-bound nanovesicles (MBV)-both derived from the human umbilical cord MSC (UC-MSC) via differential ultracentrifugation. Different phenotypes of human monocyte-derived macrophages (MDM) were used to study the anti-inflammatory properties of EV in vitro, and the medial meniscectomy-induced rat model of knee osteoarthritis (MMx) was used in vivo. The study found that both EV reduced pro-inflammatory cytokines IL-6 and TNF-α in MDM. However, exosomes showed superior results, preserving the extracellular matrix (ECM) of hyaline cartilage, and reducing synovitis more effectively than MBVs. Additionally, exosomes downregulated inflammatory markers (TNF-α, iNOS) and increased Arg-1 expression in macrophages and synovial fibroblasts, indicating a stronger anti-inflammatory effect. These results suggest UC-MSC exosomes as a promising therapeutic option for OA, with the potential for modulating inflammation and promoting joint tissue regeneration.

Role of tumor-derived exosomes mediated immune cell reprograming in cancer

Tumor-derived exosomes (TDEs), as topologies of tumor cells, not only carry biological information from the mother, but also act as messengers for cellular communication. It has been demonstrated that TDEs play a key role in inducing an immunosuppressive tumor microenvironment (TME). They can reprogram immune cells indirectly or directly by delivering inhibitory proteins, cytokines, RNA and other substances. They not only inhibit the maturation and function of dendritic cells (DCs) and natural killer (NK) cells, but also remodel M2 macrophages and inhibit T cell infiltration to promote immunosuppression and create a favorable ecological niche for tumor growth, invasion and metastasis. Based on the specificity of TDEs, targeting TDEs has become a new strategy to monitor tumor progression and enhance treatment efficacy. This paper reviews the intricate molecular mechanisms underlying the immunosuppressive effects induced by TDEs to establish a theoretical foundation for cancer therapy. Additionally, the challenges of TDEs as a novel approach to tumor treatment are discussed.

Snorkel-tag based affinity chromatography for recombinant extracellular vesicle purification

Extracellular vesicles (EVs) are lipid nanoparticles and play an important role in cell-cell communications, making them potential therapeutic agents and allowing to engineer for targeted drug delivery. The expanding applications of EVs in next generation medicine is still limited by existing tools for scaling standardized EV production, single EV tracing and analytics, and thus provide only a snapshot of tissue-specific EV cargo information. Here, we present the Snorkel-tag, for which we have genetically fused the EV surface marker protein CD81, to a series of tags with an additional transmembrane domain to be displayed on the EV surface, resembling a snorkel. This system enables the affinity purification of EVs from complex matrices in a non-destructive form while maintaining EV characteristics in terms of surface protein profiles, associated miRNA patterns and uptake into a model cell line. Therefore, we consider the Snorkel-tag to be a widely applicable tool in EV research, allowing for efficient preparation of EV standards and reference materials, or dissecting EVs with different surface markers when fusing to other tetraspanins in vitro or in vivo.

Exosome-based nanoparticles and cancer immunotherapy

Over the past decades, cancer immunotherapy has encountered challenges such as immunogenicity, inefficiency, and cytotoxicity. Consequently, exosome-based cancer immunotherapy has gained rapid traction as a promising alternative. Exosomes, a type of extracellular vesicles (EVs) ranging from 50 to 150 nm, are self-originating and exhibit fewer side effects compared to traditional therapies. Exosome-based immunotherapy encompasses three significant areas: cancer vaccination, co-inhibitory checkpoints, and adoptive T-cell therapy. Each of these fields leverages the inherent advantages of exosomes, demonstrating substantial potential for individualized tumor therapy and precision medicine. This review aims to elucidate the reasons behind the promise of exosome-based nanoparticles as cancer therapies by examining their characteristics and summarizing the latest research advancements in cancer immunotherapy.

Advances in exosomes utilization for clinical applications in cancer

Exosomes are regarded as having transformative potential for clinical applications. Exosome-based liquid biopsies offer a noninvasive method for early cancer detection and real-time disease monitoring. Clinical trials are underway to validate the efficacy of exosomal biomarkers for enhancing diagnostic accuracy and predicting treatment responses. Additionally, engineered exosomes are being developed as targeted drug delivery systems that can navigate the bloodstream to deliver therapeutic agents to tumor sites, thus enhancing treatment efficacy while minimizing systemic toxicity. Exosomes also exhibit immunomodulatory properties, which are being harnessed to boost antitumor immune responses. In this review, we detail the latest advances in clinical trials and research studies, underscoring the potential of exosomes to revolutionize cancer care.