Colorectal cancer (CRC) continues to be a major worldwide health issue, with elevated death rates linked to late stages of the illness. Immunotherapy has made significant progress in developing effective techniques to improve the immune system's capacity to identify and eradicate cancerous cells. This study examines the most recent advancements in CAR-T cell treatment and exosome-based immunotherapy for CRC. CAR-T cell therapy, although effective in treating blood cancers, encounters obstacles when used against solid tumours such as CRC. These obstacles include the presence of an immunosuppressive tumour microenvironment and a scarcity of tumour-specific antigens. Nevertheless, novel strategies like dual-receptor CAR-T cells and combination therapy involving cytokines have demonstrated promise in surmounting these obstacles. Exosome-based immunotherapy is a promising approach for targeted delivery of therapeutic drugs to tumour cells, with high specificity and minimal off-target effects. However, there are still obstacles to overcome in the field, such as resistance to treatment, adverse effects associated with the immune system, and the necessity for more individualised methods. The current research is focused on enhancing these therapies, enhancing the results for patients, and ultimately incorporating these innovative immunotherapeutic approaches into the standard treatment protocols for CRC.

Alzheimer's disease (AD) is characterized by the progressive spread of tau pathology throughout the brain. Inflammation has been demonstrated to be present in the disease state as well as changes in endocytic trafficking. Here we identify the Rab7 effector RILP, a protein at the intersection of inflammatory states and endocytic trafficking, as a novel player in tau propagation. We show that RILP is cleaved in AD brain and this cleavage correlates to increases in hyperphosphorylated tau. Cleavage can be induced in both BE(2) neuron-like cells as well as a microglia cell line when they are treated with the inflammatory mediators lipopolysaccharide (LPS) and ATP. This inflammatory state also enhances tau propagation between BE(2) cells, an effect that is mitigated by overexpressing a noncleavable RILP. Furthermore, microglial cells contribute to intercellular tau propagation through both the release of inflammation-associated factors and the direct uptake and secretion of tau, potentially via extracellular vesicles (EVs). In HMC3 microglial cells, RILP cleavage led to impaired tau degradation, increasing intracellular tau accumulation. Additionally, the RILP cleavage status influences EV secretion in microglia. These findings suggest that RILP cleavage alters the endocytic trafficking of tau causing increased cell-cell propagation in a cell-culture model of AD.

Metastasis remains a major cause of morbidity and mortality in patients with malignant tumors. The pre-metastatic niche is a prerequisite for distant metastasis driven by primary tumors. Circular RNAs (circRNAs), a class of single-stranded closed non-coding RNAs, exhibit high stability, evolutionary conservation, and cell-type specificity. Exosomes, as natural carriers of circRNAs, mediate intercellular communication and contribute to the formation of the pre-metastatic niche; however, the mechanisms by which they do so remain incompletely understood. This review summarizes the biological characteristics and functions of exosomal circRNAs and outlines the molecular pathways through which they shape the tumor pre-metastatic microenvironment, with emphasis on immunosuppression, vascular permeability, extracellular matrix remodeling, and lymphangiogenesis. This is the first review to focus on the functional roles and molecular mechanisms of exosomal circRNAs in pre-metastatic niche regulation, providing a basis for the development of therapeutic strategies targeting metastatic progression.

Cancer stem cells (CSC) play a crucial role in pancreatic ductal adenocarcinoma (PDAC) progression and therapeutic resistance. However, the underlying mechanisms and potential targeted treatment strategies remain poorly understood. In this study, we employed single-cell RNA sequencing and exosomal profiling, identifying TSPAN8-enriched exosomes secreted by CSC, which are associated with poor survival rates in PDAC patients. They enhanced stemness in the surrounding non-stem cancer cells (NSCC) by activating the Sonic Hedgehog (Hh) signalling pathway. This exosomal TSPAN8-Hh signalling axis significantly increases the clonogenic ability, invasiveness, and chemoresistance of PDAC cells. Furthermore, TSPAN8-enriched exosomes promoted a higher stem cell frequency, tumourigenicity, and tumour growth rate in vivo, confirming their critical roles in PDAC malignant progression. Our findings underscore the importance of TSPAN8-enriched exosomes for CSC-NSCC communication during PDAC progression.

The efficacy of chimeric antigen receptor (CAR) T cells against solid tumors is limited. The molecular mechanisms underlying CAR T cell resistance are yet to be elucidated and new strategies need to be developed to improve treatment outcomes. Here we report that solid tumors respond to CAR T cells by upregulating the secretion of small extracellular vesicles carrying tumor antigens, which are horizontally transferred to CAR T cells, leading to antigen recognition and CAR T cell fratricide. Engineered CAR T cells armored with Serpin B9, a major granzyme B inhibitor, show decreased fratricide and increased vitality, tumor infiltration, and antitumor activity in female mice. Moreover, Serpin B9-armored CAR T cells show higher efficacy than parental CAR T cells in treating solid tumors when combined with the anti-programmed death 1 antibody. Our study demonstrates a mechanism that limits CAR T cell function and suggests an improved strategy in tumor treatment.

Endothelial dysfunction is a pivotal contributor to cardiovascular complications in individuals with diabetes. However, the precise role of macrophages and their exosomes in the diabetic milieu remains elusive.

Exosomes (Exos) were isolated from the supernatants of macrophages treated with advanced glycation end products (AGE) or bovine serum albumin (BSA) using ultracentrifugation. Following coculture with AGE-Exos or BSA-Exos, human umbilical vein endothelial cells (HUVECs) were subjected to CCK-8, EdU, cell migration, monocyte adhesion, and tube formation assays. ELISA and Western blotting were employed to assess inflammatory cytokine release and protein expression levels in HUVECs. The miRNA expression profiles of AGE-Exos and BSA-Exos were analysed using miRNA arrays. Potential targets of miR-22-5p were predicted via miRNA databases and validated through RT‒qPCR, dual-luciferase reporter assays, and rescue experiments. Furthermore, a Rab27a knockout mouse model of type 2 diabetes mellitus (T2DM) was established by intraperitoneal injection of Streptozotocin. Aortic tissues were analysed via immunofluorescence for CD63 and CD31 expression, immunohistochemistry for VCAM-1 and ICAM-1 expression, and Western blotting for FOXP1 expression.

AGE stimulation increased the secretion of exosomes from macrophages. Compared with BSA-Exos, AGE-Exos significantly impaired endothelial cell proliferation, migration, and tube formation capabilities while increasing monocyte adhesion and proinflammatory cytokine release without affecting cell viability. miR-22-5p was enriched in AGE-Exos, which were subsequently transferred to HUVECs, specifically targeting FOXP1, resulting in endothelial dysfunction. Overexpression of miR-22-5p in HUVECs using lentiviral vectors recapitulated the inflammatory effects observed with AGE-Exos, whereas anti-miR-22-5p conferred protective effects. Rab27a knockout significantly reduced exosome accumulation in T2DM model mouse aortic tissues, alleviating endothelial discontinuity, downregulating VCAM-1 and ICAM-1 expression, and upregulating FOXP1 expression.

AGE-induced release of macrophage-derived exosomes may partially depend on Rab27a transport, which delivers miR-22-5p to ECs. This miR-22-5p targets FOXP1 in ECs, leading to inflammation and resulting in endothelial dysfunction that accelerates the development of diabetic vascular lesions.

Multiple myeloma (MM), characterised by the clonal proliferation of plasma cells in the bone marrow, is the second most common haematological malignancy worldwide. Although there is now an impressive artillery of therapeutics to tackle this condition, resistance remains a prevalent issue. The bone marrow microenvironment performs a crucial role in supporting MM pathogenesis and promoting the development of therapeutic resistance. Extracellular vesicles (EVs), small vesicles that carry bioactive molecules, are a key component of cell-to-cell communication within the bone marrow microenvironment. In this review, we summarise the contribution of EVs to disease progression and anticancer treatment resistance and discuss the potential therapeutic applications of EVs in MM.

Exosomes, characterized by their bilayer lipid structure, are crucial in mediating intercellular signaling and contributing to various physiological processes. Tumor cells produce distinct exosomes facilitating cancer progression, angiogenesis, and metastasis by conveying signaling molecules. A notable feature of these tumor-derived exosomes is the presence of programmed death-ligand 1 (PD-L1) on their surface. The PD-L1/programmed cell death receptor-1 (PD-1) signaling axis serves as a critical immune checkpoint, enabling tumors to evade immune detection and antitumor activity. The advancement of immunotherapy targeting the PD-1/PD-L1 pathway has significantly impacted the treatment landscape for non-small cell lung cancer (NSCLC). Despite its promise, evidence indicates that many patients experience limited responses or develop resistance to PD-1/PD-L1 inhibitors. Recent studies suggest that exosomal PD-L1 contributes to this resistance by modulating immune responses and tumor adaptability. This study reviews the PD-1/PD-L1 pathway's characteristics, current clinical findings on PD-L1 inhibitors in NSCLC, and exosome-specific attributes, with a particular focus on exosomal PD-L1. Furthermore, it examines the growing body of research investigating the role of exosomal PD-L1 in cancer progression and response to immunotherapy, underscoring its potential as a target for overcoming resistance in NSCLC treatment.

Spinal cord injury (SCI) is a devastating event for the central nervous system (CNS), often resulting in the loss of sensory and motor functions. It profoundly affects both the physiological and psychological well-being of patients, reducing their quality of life while also imposing significant economic pressure on families and the healthcare system. Due to the complex pathophysiology of SCI, effective treatments for promoting recovery remain scarce. Mesenchymal stem cell-derived exosomes (MSC-Exos) offer advantages such as low immunogenicity, good biocompatibility, and the ability to cross the blood-spinal cord barrier (BSCB). In preclinical studies, they have progressively shown efficacy in promoting SCI repair and functional recovery. However, the low yield and insufficient targeting of MSC-Exos limit their therapeutic efficacy. Currently, genetic engineering and other preprocessing techniques are being employed to optimize both the yield and functional properties of exosomes, thereby enhancing their therapeutic potential. Therefore, this paper provides an overview of the pathophysiology of SCI and the biogenesis of exosomes. It also summarizes current approaches to optimizing exosome performance. Additionally, it details the mechanisms through which optimized exosomes provide neuroprotection and explores the potential of combined treatments involving MSC-Exos and hydrogels.

Alpha-synuclein (αsyn) is the key pathogenic protein implicated in synucleinopathies including Parkinson's disease (PD) and dementia with Lewy bodies (DLB). In these diseases, αsyn is thought to spread between cells where it accumulates and induces pathology; however, mechanisms that drive its propagation or aggregation are poorly understood. We have previously reported that the small GTPase Rab27b is elevated in human PD and DLB and that it can mediate the autophagic clearance and toxicity of αsyn in a paracrine αsyn cell culture model. Here, we expanded our previous work and characterized the role of Rab27b in neuronal lysosomal processing and αsyn clearance. We found that Rab27b KD in this αsyn-inducible neuronal model resulted in lysosomal dysfunction and increased αsyn levels in lysosomes. Similar lysosomal proteolytic defects and enzymatic dysfunction were observed in both primary neuronal cultures and brain lysates from male and female Rab27b knock-out (KO) mice. αSyn aggregation was exacerbated in Rab27b KO neurons upon treatment with αsyn preformed fibrils. We found no changes in lysosomal counts or lysosomal pH in either model, but we did identify changes in acidic vesicle trafficking and in lysosomal enzyme maturation and localization, which may drive lysosomal dysfunction and promote αsyn aggregation. Rab27b OE enhanced lysosomal activity and reduced insoluble αsyn accumulation. Finally we found elevated Rab27b levels in human postmortem incidental Lewy body disease subjects relative to healthy controls. These data suggest the role of Rab27b in neuronal lysosomal activity and identify it as a potential therapeutic target in synucleinopathies.

Metabolic dysfunction-associated steatohepatitis (MASH) is an advanced form of liver disease with adverse outcomes. Manipulating interorgan communication is considered a promising strategy for managing metabolic disease, including steatohepatitis. Here, we report that remote limb ischemic conditioning (RIC), a clinically validated therapy for distant organ protection by transient muscle ischemia, significantly alleviated steatohepatitis in different mouse models. The beneficial effect of limb ischemic conditioning was mediated by muscle-to-liver transfer of small extracellular vesicles (sEVs) and their cargo microRNAs, leading to elevation of miR-181d-5p in the liver. Hepatic miR-181d-5p overexpression faithfully mirrored the molecular and histological benefits of limb ischemic conditioning by suppressing nuclear receptor 4A3 (NR4A3). Furthermore, circulating EVs from human volunteers undergoing limb ischemic conditioning improved steatohepatitis and transcriptomic perturbations in primary human hepatocytes and animal models. Our data underscore the translational potential of limb ischemic conditioning for steatohepatitis management and extend our understanding of muscle-liver crosstalk.

Autophagic and endosomal pathways coordinately contribute to HBV virions and subviral particles (SVPs) production. To date, limited evidence supports that HBV and exosomes have a common pathway for their biogenesis and secretion. The final steps of HBV production and release have not yet been well studied.

We examined the production and release of HBV virions and SVPs by using GW4869 (N,N'-Bis[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]-3,3'-pht hal amide dihydrochloride), a small molecule inhibiting ceramide-mediated inward membrane budding. Neutral sphingomyelinase, the target of GW4869, and RAB27A and -B,  2 small GTPases involved in exosome release control, were silenced using gene silencing to confirm the results obtained. Western blot, immunofluorescence staining, and confocal microscopy were applied.

GW4869 inhibited HBV virion release, causing their accumulation along with SVPs in hepatocytes. This triggered cellular endoplasmic reticulum stress, leading to protein kinase B-mechanistic target of rapamycin kinase signaling pathway inactivation. GW4869 treatment increased autophagosome formation and impaired autophagic degradation by blocking autophagosome-lysosome fusion. Consequently, HBsAg is increasingly localized to autophagosomes and late endosomes/multivesicular bodies. Silencing neutral sphingomyelinase yielded consistent results. Similarly, RAB27A silencing inhibited HBV virion and SVP secretion, causing their accumulation within hepatoma cells. Notably, GW4869 treatment, as well as RAB27A and -B silencing, increased the presence of LC3+CD63+HBsAg+ complexes.

Our results demonstrate the involvement of the autophagosome-late endosome/multivesicular bodies-exosome axis in regulating HBV production and release, highlighting amphisomes as a potential platform for HBV release.

Extracellular vesicles (EVs) are important mediators of intercellular communication and have various roles in physiological and pathological processes. Discovery of regulators of EV biogenesis and release has led to significant improvements in our understanding of EV biology and has highlighted disease-specific pathways. Large scale discovery studies of EV regulators are limited by conventional methods of EV analysis with limited throughput and sensitivity. To address this, this study presents a high-throughput flow cytometry-based platform for the quantification of EVs released from cells. Here, a system was developed using the MDA-MB-231 cell line stably expressing ZsGreen, which passively loads ZsGreen proteins into EVs, and nanoscale flow cytometry. EV detection and quantitation was optimized and validated for a 96-well format. The high-throughput flow cytometry screening platform quantified the effect of 156 kinase inhibitors on EV number and identified AZ191 - a DYRK1b inhibitor - as a potent EV inhibitor. DYRK1b inhibition and knockdown confirmed a significant reduction in total EV number, with small EVs demonstrating the largest reduction. DYRK1b knockdown altered the intracellular distribution of EV marker CD63, suggesting a role for DYRK1b in EV trafficking. In conclusion, our study establishes a platform for high-throughput analysis of EV dynamics and introduces DYRK1b kinase as a novel EV-regulator.

Exosomes are actively produced extracellular vesicles, released from different cell types, that exert important regulatory roles in vital cellular functions. Tumor-derived exosomes (TDEs) have received increasing attention because they enable intercellular communication between the neoplastic and non-neoplastic cells present in the microenvironment of tumors, affecting important functions of different types of mesenchymal stem cells (MSCs) with the ability to self-renew and differentiate. MSC-derived exosomes (MSC-exos) carry a variety of bioactive molecules that can interact with specific cellular targets and signaling pathways, influencing critical processes in tumor biology, and exhibiting properties that either promote or inhibit tumor progression. They can regulate the tumor microenvironment by modulating immune responses, enhancing or suppressing angiogenesis, and facilitating tumor cells' communication with distant sites, thus altering the behavior of non-cancerous cells present in the microenvironment. Herein, we explore the main functions of TDEs and their intricate interactions with MSC-exos, in terms of enhancing cancer progression, as well as their promising clinical applications as tumor microenvironment modulators.

Neuropilin-1 (NRP1) is a transmembrane glycoprotein that functions as a co-receptor with various cellular functions. Our previous studies identified the NRP1 exon 4-skipping (NRP1-ΔE4) splice variant as an aggressive metastasis driver by activating endosomal signals. Here, we demonstrate the critical role of glycosaminoglycan (GAG) modification in regulating NRP1-ΔE4's cellular trafficking and oncogenic activity. NRP1-ΔE4 undergoes constitutive internalization into endosomes and subsequent exosomal release from colorectal cancer (CRC) cells. Exosomal NRP1-ΔE4 enhances the migration and invasion of both donor and recipient CRC cells. Genetic or pharmacological inhibition of exosome secretion, or immunodepletion of exosomal NRP1-ΔE4, markedly reduces its metastatic potential. Notably, GAG modification at the O-glycosylation site Ser612 is essential for NRP1-ΔE4's endosomal trafficking and exosomal release. This modification also promotes the formation of a trimeric complex with Met and β1-integrin, leading to their co-internalization and accumulation in endosomes, which activates FAK signaling and drives CRC metastasis. These findings reveal GAG modification as a key regulatory process that governs the endosomal-exosomal trafficking of NRP1-ΔE4 to facilitate CRC cell dissemination.

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.

Exosomes play pleiotropic tumor-promoting functions and are secreted by fusion of multivesicular bodies (MVBs) with the plasma membrane. However, MVBs are also directed to lysosomes for degradation, and the mechanism controlling different fates of MVBs remains elusive. Here, we show that the pro-tumor protein WDR4 enhances exosome secretion from mouse and human cancer cells through degrading the endosomal sorting complex required for transport (ESCRT)-associated Bro1-family protein PTPN23. Mechanistically, PTPN23 and ALIX compete for binding to syntenin, thereby directing MVBs toward degradation and secretion, respectively. ALIX, but not PTPN23, recruits actin-capping proteins CAPZA1/CAPZB to prevent branched filamentous actin (F-actin) accumulation around MVBs, thus enabling MVBs trafficking to the cell periphery for secretion. Functionally, WDR4/ALIX-dependent exosomes load a set of pro-tumor proteins through LAMP2A, thereby potentiating metastasis and immune evasion in mice. Our study highlights a previously unappreciated coupling between the biogenesis mechanism and the fate decision of MVBs and its importance in determining exosomal cargos, which have a profound impact on tumor progression.

Neurodegenerative disorders include Parkinson's disease, spinal cord injury, multiple sclerosis and Alzheimer's disease, cause gradual neuronal loss, protein misfolding, and accumulation, resulting in severe cognitive and movement deficits. Despite substantial study, therapeutic interventions are hampered by the blood-brain barrier, which prevents medication distribution to the central nervous system. Traditional pharmaceutical methods, such as small compounds, peptides, and inhibitors, have shown minimal effectiveness in addressing this obstacle. Exosomes are nanoscale membrane-bound vesicles that are primarily engaged in intercellular communication. They have the inherent capacity to cross the blood-brain barrier, which allows them to be used as medication delivery vehicles for brain illness therapy. Exosomes may be derived from a variety of cells like microglia, astrocytes identified according to origin, increasing their flexibility as drug delivery vehicles. Advanced engineering approaches optimise exosomes for tailored distribution across the blood-brain barrier, paving the path for novel neurodegenerative disease treatments. This review discusses the promise of exosome-based drug delivery, focussing on their composition, biogenesis, engineering, and applications in treating central nervous system illnesses, eventually overcoming the unmet hurdles of crossing the blood-brain barrier.

Previous studies have demonstrated that lactate accumulation, a common hallmark for metabolic deprivation in solid tumors, could actively drive tumor invasion and metastasis. However, whether lactate influences the biogenesis of tumor-derived exosomes (TDEs), the prerequisite for distant metastasis formation, remains unknown. Here, we demonstrated that extracellular lactate, after taken up by tumor cells via lactate transporter MCT1, drove the release of TDE mainly through facilitating multivesicular body (MVB) trafficking towards plasma membrane instead of lysosome. Mechanistically, lactate promoted p300-mediated Rab7A lactylation, which hereafter inhibited its GTPase activity and promoted MVB docking with plasma membrane. Moreover, lactate administration enriched integrin β4 and ECM remodeling-related proteins in TDE cargos, which promoted pulmonary pre-metastatic niche formation. Combinatorial inhibition of MCT1 and p300 significantly abrogated HCC metastasis in a clinical-relevant PDX model. In summary, we demonstrated that lactate promote TDE biogenesis and HCC pulmonary metastasis, and proposed a potential clinical strategy targeting TDEs to prevent HCC metastasis.

As we progress into the 21st century, cancer stands as one of the most dreaded diseases. With approximately one in every four individuals facing a lifetime risk of developing cancer, cancer remains one of the most serious health challenges worldwide. Its multifaceted nature makes it an arduous and tricky problem to diagnose and treat. Over the years, researchers have explored plenty of approaches and avenues to improve cancer management. One notable strategy includes the study of extracellular vesicles (EVs) as potential biomarkers and therapeutics. Among these EVs, exosomes have emerged as particularly promising candidates due to their unique characteristic properties and functions. They are small membrane-bound vesicles secreted by cells carrying a cargo of biomolecules such as proteins, nucleic acids, and lipids. These vesicles play crucial roles in intercellular communication, facilitating the transfer of biological information between cell-to-cell communication. Exosomes transport cargoes such as DNA, RNA, proteins, and lipids involved in cellular reprogramming and promoting cancer. In this review, we explore the molecular composition of exosomes, significance of exosomes chemistry in cancer development, and its theranostic application as well as exosomes research complications and solutions.

Filopodia are dynamic adhesive cytoskeletal structures that are critical for directional sensing, polarization, cell-cell adhesion, and migration of diverse cell types. Filopodia are also critical for neuronal synapse formation. While dynamic rearrangement of the actin cytoskeleton is known to be critical for filopodia biogenesis, little is known about the upstream extracellular signals. Here, we identify secreted exosomes as potent regulators of filopodia formation. Inhibition of exosome secretion inhibited the formation and stabilization of filopodia in both cancer cells and neurons and inhibited subsequent synapse formation by neurons. Rescue experiments with purified small and large extracellular vesicles (EVs) identified exosome-enriched small EVs (SEVs) as having potent filopodia-inducing activity. Proteomic analyses of cancer cell-derived SEVs identified the TGF-β family coreceptor endoglin as a key SEV-enriched cargo that regulates filopodia. Cancer cell endoglin levels also affected filopodia-dependent behaviors, including metastasis of cancer cells in chick embryos and 3D migration in collagen gels. As neurons do not express endoglin, we performed a second proteomics experiment to identify SEV cargoes regulated by endoglin that might promote filopodia in both cell types. We discovered a single SEV cargo that was altered in endoglin-KD cancer SEVs, the transmembrane protein Thrombospondin Type 1 Domain Containing 7A (THSD7A). We further found that both cancer cell and neuronal SEVs carry THSD7A and that add-back of purified THSD7A is sufficient to rescue filopodia defects of both endoglin-KD cancer cells and exosome-inhibited neurons. We also find that THSD7A induces filopodia formation through activation of the Rho GTPase, Cdc42. These findings suggest a new model for filopodia formation, triggered by exosomes carrying THSD7A.

Extracellular vesicles (EVs) are an important mediator of intercellular communication and the regulation of processes occurring in cells and tissues. The processes of EVs secretion by cells into the extracellular space (ECS) leads to their interaction with its participants. The ECS is a dynamic structure that also takes direct part in many processes of intercellular communication and regulation. Changes in the ECS can also be associated with pathological processes, such as increased acidity during the development of solid tumors, changes in the composition and nature of the organization of the extracellular matrix (ECM) during fibroblast activation, an increase in the content of soluble molecules during necrosis, and other processes. The interaction of these two systems, the EVs and the ESC, leads to structural and functional alteration in both participants. In the current review, we will focus on these alterations in the EVs which we termed post-secretory modification and processes (PSMPs) of EVs. PSPMs can have a significant effect on the immediate cellular environment and on the spread of the pathological process in the body as a whole. Thus, it can be assumed that PSPMs are one of the important stages in the regulation of intercellular communication, which has significant differences in the norm and in pathology.

The development of lipid-based mRNA delivery systems has significantly facilitated recent advances in mRNA-based therapeutics. Liposomes, as the pioneering class of mRNA vectors, continue to lead in clinical trials. We previously developed a histidylated liposome that demonstrated efficient nucleic acid delivery. In this study, the liposome preparation process was optimized by freeze-drying followed by extrusion to homogenize size distribution and improve storage stability. A comprehensive characterization of these LYX liposomes was performed, including evaluation in cellular and murine animal models. LYX liposomes can be stored for up to one year at 4 °C, maintaining a stable size (150 ± 10 nm) and polydispersity index (0.10 ± 0.02), while preserving their transfection efficacy. They exhibit high encapsulation efficacy (∼95 %) and protect mRNA from RNase degradation. Lamellar organization was confirmed by Small Angle X-ray Scattering and CryoTEM, and intracellular trafficking was examined using confocal microscopy. LYX-mRNA lipoplexes can transfect both cell lines and primary cells, albeit with a lower transfection efficacy compared to the commercial Lipofectamine MessengerMAX™ vector. Our data suggest that this could be attributed to slower cell uptake and reduced endosomal escape of LYX. LYX liposomes effectively delivered mRNA encoding therapeutic BMP2 and BMP9 molecules, producing significant amounts of functional proteins that successfully induced BMP signaling. In addition, in vivo studies demonstrated the potential of LYX lipoplexes when incorporated into hydrogels and implanted subcutaneously in mice. These findings provided evidence that LYX liposomes are a promising platform for mRNA delivery, offering versatility for multiple applications.

Exosomes are critical mediators of cell-to-cell communication in physiological and pathological processes, due to their ability to deliver a variety of bioactive molecules. Tumor-derived exosomes (TDEs), in particular, carry carcinogenic molecules that contribute to tumor progression, metastasis, immune escape, and drug resistance. Thus, TDE inhibition has emerged as a promising strategy to combat cancer. In this review, we discuss the key mechanisms of TDE biogenesis and secretion, emphasizing their implications in tumorigenesis and cancer progression. Moreover, we provide an overview of small-molecule TDE inhibitors that target specific biogenesis and/or secretion pathways, highlighting their potential use in cancer treatment. Lastly, we present the existing obstacles and propose corresponding remedies for the future development of TDE inhibitors.

Epithelial cancer onset occurs through sequential stages of cell lineage conversion and functional dysregulation. Dysplasia is a precancerous lesion defined as a direct precursor to cancer and is histologically defined as a transition stage between pre-cancer and cancer, but molecular and biological mechanisms controlling its transformation to malignancy are underdetermined. Here, we discover the crucial role of the actin stabilization and exosome secretion-regulatory protein cortactin in dysplastic cell transformation to adenocarcinoma.

We engineered a CRISPR/Cas9-based cortactin knock-out (KO) dysplasia organoid model established from dysplastic tissue and examined malignant roles of cortactin during gastric cancer development in vitro and in vivo.

Although dysplastic cell identity remained unchanged, the cortactin KO organoids exhibited a decrease in cellular organization and multicellular protrusions, which are considered aggressive features when observed in vitro. When injected into the flank of nude mice, cortactin KO cells failed malignant transformation into adenocarcinoma and solid tumor formation with reduced recruitment of fibroblasts and macrophages. In addition, cortactin KO cells showed diminished exosome secretion levels, and adenocarcinoma development was impaired when exosome secretion was inhibited in cortactin wild-type dysplastic cells.

These data suggest that cortactin is a functional element of membrane dynamics, malignant changes, and exosome secretion in dysplastic cells, and solid gastric tumor formation associated with alteration of the tumor microenvironment.

KRAS mutations are instrumental in the development and progression of pancreatic ductal adenocarcinoma (PDAC). Nevertheless, the efficacy of direct targeting of KRAS mutations to inhibit tumor development remains doubtful. It is therefore necessary to gain a deeper insight into the mechanism in which KRAS mutations influence the effectiveness of clinical treatments. In this study, KRASG12D protein was detected in cancer-associated fibroblasts (CAFs) from clinical samples of PDAC. In vitro experiments demonstrated that KRASG12D protein in CAFs was not expressed from its own mutant gene but was derived from the ingestion of tumor cell-derived extracellular vesicles (EVs). The presence of KRASG12D protein in CAFs resulted in enhanced proliferation and migration. Furthermore, KRASG12D-containing CAFs were observed to promote tumor chemoresistance to gemcitabine treatment both in vitro and in vivo. Application of a KRAS mutation-specific inhibitor, MRTX1133, has been demonstrated to reverse chemoresistance in PDAC. Moreover, clinical data suggest that patients with KRAS mutations have poorer prognosis following adjuvant chemotherapy. These findings elucidate the mechanism by which oncogenic KRAS mutations promote cancer chemoresistance and remodel tumor environment in a non-autonomous manner, suggesting a novel strategy for targeting KRAS mutations to enhance chemosensitivity in PDAC.

Alterations in signalling pathways fuel the growth and progression of melanoma. Therefore, understanding these processes is essential for developing effective treatment strategies. RAB27A and RAB27B are known to possess oncogenic effects by modulating cancer cell proliferation, invasion and drug resistance in various types of cancer, including melanoma. These proteins are mostly acknowledged as coordinators of the vesicular trafficking, however, their function in cellular signaling is less recognized. Therefore we aimed to investigate the relationship between RAB27 and oncogenic or signalling proteins in melanoma cells.

We generated RAB27A knockout (KO) in SkMel28, A375, and patient-derived DMBC12 melanoma cell lines. Additionally, a double RAB27A/B knockout (dKO) A375 cell line was created. Firstly, we applied the Proteome Profiler array to identify proteins differentially expressed upon RAB27A/B loss. Subsequently, we picked selected specific proteins for a further in-depth analysis using RT-PCR, Western blot, and flow cytometry.

We found that silencing RAB27 markedly decreased the levels of various intracellular proteins linked with proliferation, invasion, angiogenesis, adhesion, or EMT at a cell-line dependent level. Among others, we observed a link between the expression of RAB27 and EGFR, HER2 and HER3. Altered levels of HER receptors disturbed the downstream signaling pathways by reducing the phosphorylation of AKT and ERK1/2 proteins.

Our findings present novel, previously unpublished data on the relationship between HER family receptor expression and potential activity, and the involvement of RAB27 in melanoma cells.

Senescence is a nonproliferative survival state that cancer cells can enter to escape therapy. In addition to soluble factors, senescence cells secrete extracellular vesicles (EV), which are important mediators of intercellular communication. To explore the role of senescent cell (SC)-derived EVs (senEV) in inflammatory responses to senescence, we developed an engraftment-based senescence model in wild-type mice and genetically blocked senEV release in vivo, without significantly affecting soluble mediators. SenEVs were both necessary and sufficient to trigger immune-mediated clearance of SCs, thereby suppressing tumor growth. In the absence of senEVs, the recruitment of MHC-II+ antigen-presenting cells (APC) to the senescence microenvironment was markedly impaired. Blocking senEV release redirected the primary target of SC signaling from APCs to neutrophils. Comprehensive transcriptional and proteomic analyses identified six ligands specific to senEVs, highlighting their role in promoting APC-T cell adhesion and synapse formation. APCs activated CCR2+CD4+ TH17 cells, which seemed to inhibit B-cell activation, and CD4+ T cells were essential for preventing tumor recurrence. These findings suggest that senEVs complement the activity of secreted inflammatory mediators by recruiting and activating distinct immune cell subsets, thereby enhancing the efficient clearance of SCs. These conclusions may have implications not only for tumor recurrence but also for understanding senescence during de novo carcinogenesis. Consequently, this work could inform the development of early detection strategies for cancer based on the biology of cellular senescence. Significance: Chemotherapy-treated senescent tumor cells release extracellular vesicles that trigger an immune response and suppress tumor recurrence. See related commentary by Almeida and Melo, p. 833.

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.

Current decade witnessed the emergence and re-emergence of many viruses, which affected public health significantly. Viruses mainly utilize host cell machinery to promote its growth, and spread of these diseases. Numerous factors influence virus-host cell interactions, of which extracellular vesicles play an important role, where they transfer information both locally and distally by enclosing viral and host-derived proteins and RNAs as their cargo. Thus, they play a dual role in mediating virus infections by promoting virus dissemination and evoking immune responses in host organisms. Moreover, it acts as a double-edged sword during these infections. Advances in extracellular vesicles regulating emerging and reemerging virus infections, particularly in the context of SARS-CoV-2, Dengue, Ebola, Zika, Chikungunya, West Nile, and Japanese Encephalitis viruses are discussed in this review.

Recent findings implicate somatic NRASQ61R mutation in human endothelial cells in the pathogenesis of vascular anomalies. Our previous study demonstrated that RAB27B, a small GTPase of the RAB family, regulates NRAS palmitoylation in leukemia cells and is essential for NRAS-mutant leukemia development. However, the role of RAB27B in NRASQ61R mutant endothelial cells are still unknown. Our present study revealed that knockdown of RAB27B, but not knockdown of RAB27A, inhibited the enhanced proliferation and migration of human umbilical vein endothelial cells (HUVEC) overexpressing NRASQ61R by suppressing ERK activation. Notably, RAB27B protein and gene expression levels were significantly elevated in HUVEC overexpressing NRASQ61R compared to those overexpressing NRASWT or empty vector. Treatment with a MEK1/2 inhibitor, but not a PI3K/mTOR inhibitor, markedly decreased RAB27B gene expression in HUVEC overexpressing NRASQ61R. Furthermore, we identified CCAAT enhancer binding protein beta as a downstream transcription factor of NRASQ61R/ERK pathway that induced RAB27B gene expression. Taken together, our study unmasked a positive feedback loop between NRASQ61R mutation and RAB27B expression in endothelial cells. Moreover, RAB27B is associated with the dysfunction of NRASQ61R mutant endothelial cells, highlighting RAB27B as a potential therapeutic target for NRAS-mutant vascular anomalies.

Unusual symptoms, rapid progression, lack of reliable early diagnostic biomarkers, and lack of efficient treatment choices are the ongoing challenges of pancreatic cancer. Numerous research studies have demonstrated the correlation between exosomes and various aspects of pancreatic cancer. In light of these facts, exosomes possess the potential to play functional roles in the treatment, prognosis, and diagnosis of the pancreatic cancer. In the present study, we reviewed the most recent developments in approaches for exosome separation, modification, monitoring, and communication. Moreover, we discussed the clinical uses of exosomes as less invasive liquid biopsies and drug carriers and their contribution to the control of angiogenic activity of pancreatic cancer. Better investigation of exosome biology would help to effectively engineer therapeutic exosomes with certain nucleic acids, proteins, and even exogenous drugs as their cargo. Circulating exosomes have shown promise as reliable candidates for pancreatic cancer early diagnosis and monitoring in high-risk people without clinical cancer manifestation. Although we have tried to reflect the status of exosome applications in the treatment and detection of pancreatic cancer, it is evident that further studies and clinical trials are required before exosomes may be employed as a routine therapeutic and diagnostic tools for pancreatic cancer.

The aging population has led to a global issue of osteoarthritis (OA), which not only impacts the quality of life for patients but also poses a significant economic burden on society. While biotherapy offers hope for OA treatment, currently available treatments are unable to delay or prevent the onset or progression of OA. Recent studies have shown that as nanoscale bioactive substances that mediate cell communication, exosomes from stem cell sources have led to some breakthroughs in the treatment of OA and have important clinical significance. This paper summarizes the mechanism and function of stem cell exosomes in delaying OA and looks forward to the development prospects and challenges of exosomes.

Extracellular vesicles (EVs) are emitted from cells throughout the body and serve as signaling molecules that mediate disease development. Emerging evidence suggests that per- and polyfluoroalkyl substances (PFAS) impact EV release and content, influencing liver toxicity. Still, the upstream regulators of EV changes affected by PFAS exposure remain unclear. This study evaluated the hypothesis that PFAS exposures, individually and in a mixture, alter the expression of genes involved in EV regulation at concentrations comparable to genes involved in global biological response mechanisms. HepG2 liver cells were treated at multiple concentrations with individual PFOS, PFOA, or PFHxA, in addition to an equimolar PFAS mixture. Gene expression data were analyzed using three pipelines for concentration-response modeling, with results compared against empirically derived datasets. Final benchmark concentration (BMC) modeling was conducted via Laplace model averaging in BMDExpress (v3). BMCs were derived at an individual gene level and across different gene sets, including Gene Ontology (GO) annotations as well as a custom EV regulation gene set. To determine relative PFAS contributions to the evaluated mixture, relative potency factors were calculated across resulting BMCs using PFOS as a standard reference chemical. Results demonstrated that PFAS exposures altered the expression of genes involved in EV regulation, particularly for genes overlapping with endoplasmic reticulum stress. EV regulatory gene changes occurred at similar BMCs as global gene set alterations, supporting concurrent regulation and the role of EVs in PFAS toxicology. This application of transcriptomics-based BMC modeling further validates its utility in capturing both established and novel pathways of toxicity.

The programmed cell death 1 (PD-1)/PD-1 ligand 1 (PD-L1) axis mediates immune evasion of tumor, and targeting this axis has achieved some clinical benefits. The regulation of PD-1 expression in immune cells has been well studied. However, whether any other potential source of immune cell-expressed PD-1 exists remains unknown. Here, we report that tumor cells express PD-1 and release PD-1 in the form of extracellular vesicles, which enters T cells and suppresses T cell function via PD-L1 in vitro. In vivo, tumor cell-derived extracellular vesicle PD-1 promotes tumor growth via disrupting peripheral T cell homeostasis, showing by decreased number of T cells and impaired function of CD8+ T cells in spleens, draining lymph nodes and tumor infiltrating lymphocytes, which is restored by PD-1-targeted antibodies. Our study provides a unique and novel perspective for immune evasion of tumor, and expands a source of PD-1 in immune cells.

Metastasis is the leading cause of cancer-related deaths. Cancer-associated fibroblasts (CAFs) are abundant components within the tumour microenvironment, playing critical roles in metastasis. Although increasing evidence supports a role for small extracellular vesicles (sEVs) in this process, their precise contribution and molecular mechanisms remain unclear, compromising the development of antimetastatic therapies. Here, we establish that CAF-sEVs drive metastasis by mediating CAF-cancer cell interaction and hyperactivating TGF-β signalling in tumour cells. Metastasis is abolished by genetically targeting CAF-sEV secretion and consequent reduction of TGF-β signalling in cancer cells. Pharmacological treatment with dimethyl amiloride (DMA) decreases CAFs' sEV secretion, reduces TGF-β signalling levels in tumour cells and abrogates metastasis and tumour self-seeding. This work defines a new mechanism required by CAFs to drive cancer progression, supporting the therapeutic targeting of EV trafficking to disable the driving forces of metastasis.

The ECM (extracellular matrix) provides the microenvironmental niche sensed by resident vascular smooth muscle cells (VSMCs). Aging and disease are associated with dramatic changes in ECM composition and properties; however, their impact on VSMC phenotype remains poorly studied.

Here, we describe a novel in vitro model system that utilizes endogenous ECM to study how modifications associated with age and metabolic disease impact VSMC phenotype. ECM was synthesized using primary human VSMCs and modified during culture or after decellularization. Integrity, stiffness, and composition of the ECM was measured using superresolution microscopy, atomic force microscopy, and proteomics, respectively. VSMCs reseeded onto the modified ECM were analyzed for viability and osteogenic differentiation.

ECMs produced in response to mineral stress showed extracellular vesicle-mediated hydroxyapatite deposition and sequential changes in collagen composition and ECM properties. VSMCs seeded onto the calcified ECM exhibited increased extracellular vesicle release and Runx2 (Runt-related transcription factor 2)-mediated osteogenic gene expression due to the uptake of hydroxyapatite, which led to increased reactive oxygen species and the induction of DNA damage signaling. VSMCs seeded onto the nonmineralized, senescent ECM also exhibited increased Runx2-mediated osteogenic gene expression and accelerated calcification. In contrast, glycated ECM specifically induced increased ALP (alkaline phosphatase) activity, and this was dependent on RAGE (receptor for advanced glycation end products) signaling with both ALP and RAGE receptor inhibition attenuating calcification.

ECM modifications associated with aging and metabolic disease can directly induce osteogenic differentiation of VSMCs via distinct mechanisms and without the need for additional stimuli. This highlights the importance of the ECM microenvironment as a key driver of phenotypic modulation acting to accelerate age-associated vascular pathologies and provides a novel model system to study the mechanisms of calcification.

Small extracellular vesicles (sEVs) facilitate intercellular communication and play a pivotal role in tumor progression. Accumulated evidence has indicated the diversity of sEVs but with limited results revealing the landscape of heterogeneity of sEVs. The heterogeneity of cargo RNA in sEVs presents the different cell origins and indicates different functions. Here, we analyzed the heterogeneity of sEVs at droplet levels from single-cell RNA sequencing results of head and neck squamous cell carcinoma (HNSCC) with the previously reported algorithm SEVtras. With the sEVs secretion activity calculated by SEVtras, we also found that the T cells held the major role of sEVs secretion. In addition, we found these sEVs secreted by T cells increased the cytotoxic ability of natural killer cells (NK cells), which illustrated an indirect manner for the anti-tumor function of T cells. These results revealed the heterogeneity of cargo RNA of sEVs in HNSCC and underlined a sEVs-dependent manner in which T cells act on NK cells and anti-tumor immunity.

Cells secrete a large variety of extracellular vesicles (EVs) to engage in cell-to-cell and cell-to-environment intercellular communication. EVs are functionally involved in many physiological and pathological processes by interacting with cells that facilitate transfer of proteins, lipids and genetic information. However, our knowledge of EVs is incomplete. Here we show that cells actively release exceptionally large (up to 20 µm) membrane-enclosed vesicles that exhibit active blebbing behavior, and we, therefore, have termed them blebbisomes. Blebbisomes contain an array of cellular organelles that include functional mitochondria and multivesicular endosomes, yet lack a definable nucleus. We show that blebbisomes can both secrete and internalize exosomes and microvesicles. Blebbisomes are released from normal and cancer cells, can be observed by direct imaging of cancer cells in vivo and are present in normal bone marrow. We demonstrate that cancer-derived blebbisomes contain a plethora of inhibitory immune checkpoint proteins, including PD-L1, PD-L2, B7-H3, VISTA, PVR and HLA-E. These data identify a very large, organelle-containing functional EV that act as cell-autonomous mobile communication centres capable of integrating and responding to signals in the extracellular environment.