Exosome Biogenesis Research Articles

Tumor-Derived Exosomes and Their Role in Breast Cancer Metastasis.

Breast cancer has been the most common cancer in women worldwide, and metastasis is the leading cause of death from breast cancer. Even though the study of breast cancer metastasis has been extensively carried out, the molecular mechanism is still not fully understood, and diagnosis and prognosis need to be improved. Breast cancer metastasis is a complicated process involving multiple physiological changes, and lung, brain, bone and liver are the main metastatic targets. Exosomes are membrane-bound extracellular vesicles that contain secreted cellular constitutes. The biogenesis and functions of exosomes in cancer have been intensively studied, and mounting studies have indicated that exosomes play a crucial role in cancer metastasis. In this review, we summarize recent findings on the role of breast cancer-derived exosomes in metastasis organotropism and discuss the potential promising clinical applications of targeting exosomes as novel strategies for breast cancer diagnosis and therapy.

Abstract 335: Hsf1 Regulates Exosome Biogenesis And Cargo Enrichment Of These Exosomes In Stem Cells Thereby Enhancing Their Potential Of Ischemic Heart Regeneration.

Introduction: Paracrine mechanism of stem cell-based therapy holds importance. However, genes regulating the paracrine factors have not been elucidated in detail. Here in this study, we evaluated the role of HSF1 in exosome biogenesis and their composition in neonatal cardiac mesenchymal stem cells (nMSCs) in concert with ischemic heart generation. Hypothesis: HSF1 in nMSCs promotes production of exosomes, functional exosomal miRs cargo, and exosome acquisition by recipient cells. Methodology: nMSCs and adult MSCs (aMSCs) were respectively isolated from right atrial appendage of neonate (<1month) and adult ( > 40 years) patients. nMSCs were knocked down (KD) for HSF1 gene using CRISPR-CAS9 technique while HSF1 gene was overexpressed (OE) in aMSCs using HSF1 overexpressing lentiviral constructs. Exosome biogenesis was evaluated using nano site technique. We next evaluated effect of HSF1 KD and OE on miRs cargo in nMSCs and aMSCs respectively. Exosome acquisition by target cells was studied by mCherry labeling technique. The potential of nMSCs and aMSCs and their corresponding exosomes to repair rat ischemic heart was evaluated under the effect of HSF1 KD and OE. Results: HSF1-KD in nMSCs resulted in significant reduction in production of exosomes, downregulation of ESCRT complex genes and therapeutic miRs viz, miR-199a, mi590-3P and miR-146. In contrast, HSF-1 over expression in aMSCs statistically increased production of exosomes, ESCRT complex genes and of therapeutic miRs. Moreover, HSF-1 OE in aMSCs resulted in statistical downregulation of miR-122, known to induce apoptosis, and downregulation of p27, a known target of miR-590. We identified that potential of nMSCs to repair ischemic heart decreased statistically after HSF1-KD while that of aMSCs increased significantly after HSF1-OE. Finally, we identified exosomes from these stem cells were preferentially taken up by cells in injured myocardium and not by cells in non-injured one and that HSF1-OE increased the uptake by recipient cells while HSF1-KD had opposite effect. Conclusion: Together, our results demonstrate that HSF-1 plays an important role in exosome biogenesis, miRs cargo enrichment and uptake of exosomes by recipient cells.

Abstract 12710: Adipocyte-Derived Exosomal Lncrna Sbf2-as1 Promotes Diabetic Myocardial Fibrosis Through Regulating Hnrnpa1/nrf2 Pathway via Sumoylation

Introduction: The inhibition of Nrf2 pathway is regarded as the dominant process that correlates with the pathogenesis of diabetic cardiomyopathy (DCM). Recently, accumulating evidence reveals that lncRNAs play key roles in regulating Nrf2 pathway. However, the underlying mechanisms remain unclear. Here, we found that adipocyte lncRNA SBF2-AS1 (SBF2-AS1) enhanced the SUMOylation of hnRNPA1, which subsequently facilitated the package of SBF2-AS1 into exosomes under high glucose conditions. Hypothesis: We hypothesized that AdEXO-SBF2-AS1 promotes diabetic myocardial fibrosis through regulating the hnRNPA1/Nrf2 pathway via SUMOylation. Methods: We examined the effect of exosomes from diabetic (db/db) mice-derived adipocytes on ANG-II-induced cardiac fibrosis and function in non-diabetic mice. In the invitro study, HG (33mmol/L)-induced AdEXO were cultured with adult human cardiac fibroblasts (aHCFs). Differentially expressed lncRNAs in AdEXO were screened using lncRNA sequencing. Results: Intramyocardial injection of diabetic AdEXO in the non-diabetic heart exacerbated myocardial fibrosis. Whereas administration of an exosomes biogenesis inhibitor attenuated cardiac fibrosis in diabetic mice. We identified SBF2-AS1 is a common molecule significantly increased in diabetic AdEXO and HG-stimulated non-diabetic AdEXO. After four weeks of ANG II infusion, EXO-db/dbWT-injected mice displayed significant fibrosis in the heart. However, interestingly, mice receiving SBF2-AS1-deficient db/db-EXO showed a decrease in cardiac fibrosis. Similarly, AdEXO-SBF2-AS1 promoted aHCFs proliferation and transformation capabilities in vitro. Mechanistically, SBF2-AS1 induced UBC9 overexpression to catalyze the SUMOylation of hnRNPA1, which facilitated its packaging into exosomes. Subsequently, exosomal SBF2-AS1 was specifically transmitted into aHCFs and epigenetically downregulated Nrf2 expression by decreasing H3K9 acetylation level in the Nrf2 promoter. Conclusions: Our findings highlight a novel mechanism whereby the AdEXO-mediated SBF2-AS1/hnRNPA1/Nrf2 regulatory axis promotes diabetic myocardial fibrosis in a SUMOylation-dependent manner and implicate SBF2-AS1 as an attractive therapeutic target for DCM.

Enterovirus 71-induced autophagosome fusion with multivesicular bodies facilitates viral RNA packaging into exosomes

Exosomes have been shown to release from cells infected by viruses and deliver viral particles, genomes, and other viral genetic elements to neighboring cells resulting in modulating host immune response. Our previous study demonstrated that exosomes released from Enterovirus 71 (EV71)-infected cells contained replication-competent EV71 RNA in complex with miR-146a, Ago2, and GW182, which can be successfully transferred to recipient/target cells to establish productive infection. However, the molecular mechanisms that control viral genome package into exosomes are still unclear. In this study, we showed that the EV71-induced autophagy response contributed to viral genome package into exosomes rather than process of exosomes biogenesis. Further study showed that the autophagosomes accumulation facilitated their fusion with MVBs, which resulted in EV71 RNA package into exosome vesicles. Moreover, prevention of autophagosomes-MVBs fusion could abolish this sorting of viral RNA into exosomes. Knockdown of GW182 or Ago2 could weaken the replication ability of exosomal EV71 RNA in recipient cells through decreasing the amount of miR-146a in exosomes, but did not affect the package of viral RNA into exosomes. Our findings strongly suggested that the accumulation of autophagosomes that were induced by EV71 infection play a key role on viral spreading through exosome vesicles.

Type 2 diabetes mellitus stimulated pulmonary vascular inflammation and exosome biogenesis in rats.

It has been shown that type 2 Diabetes Mellitus (T2DM) changes the paracrine activity of several cell types. Whether the biogenesis of exosomes is changed during diabetic conditions is the subject of debate. Here, we investigated the effect of T2M on exosome biogenesis in rat pulmonary tissue. Rats received a high-fat diet regime and a single low dose of Streptozocin to mimic the T2DM-like condition. A total of8 weeks after induction of T2DM, rats were subjected to several analyses. Besides histological examination, vascular cell adhesion molecule 1(VCAM-1) levels were detected using immunohistochemistry (IHC) staining. Transcription of several genes such as IL-1β, Alix, and Rab27b was calculated by real-time polymerase chain reactionassay. Using western blot analysis, intracellular CD63 levels were measured. The morphology and exosome secretion activity were assessed using acetylcholinesterase (AChE) assay and scanning electron microscopy, respectively. Histological results exhibited a moderate-to-high rate of interstitial pneumonia with emphysematous changes. IHC staining showed an increased VCAM-1 expression in the diabetic lungs compared with the normal conditions (p < .05). Likewise, we found the induction of IL-1β, and exosome-related genes Alix and Rab27b under diabetic conditions compared with the control group (p < .05). Along with these changes, protein levels of CD63 and AChE activity were induced upon the initiation of T2DM, indicating accelerated exosome biogenesis. Taken together, current data indicated the induction of exosome biogenesis in rat pulmonary tissue affected by T2DM. It seems that the induction of inflammatory niche is touted as a stimulatory factor to accelerate exosome secretion.

Extracellular vesicles biogenesis, isolation, manipulation and genetic engineering for potential in vitro and in vivo therapeutics: An overview.

The main goals of medicine consist of early detection and effective treatment of different diseases. In this regard, the rise of exosomes as carriers of natural biomarkers has recently attracted a lot of attention and managed to shed more light on the future of early disease diagnosis methods. Here, exosome biogenesis, its role as a biomarker in metabolic disorders, and recent advances in state-of-art technologies for exosome detection and isolation will be reviewed along with future research directions and challenges regarding the manipulation and genetic engineering of exosomes for potential in vitro and in vivo disease diagnosis approaches.

Graphene Oxide Enhances Biogenesis and Release of Exosomes in Human Ovarian Cancer Cells.

Exosomes, which are nanovesicles secreted by almost all the cells, mediate intercellular communication and are involved in various physiological and pathological processes. We aimed to investigate the effects of graphene oxide (GO) on the biogenesis and release of exosomes in human ovarian cancer (SKOV3) cells. Exosomes were isolated using ultracentrifugation and ExoQuick and characterized by various analytical techniques. The expression levels of exosome markers were analyzed via quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Graphene oxide (10-50 μg/mL), cisplatin (2-10 μg/mL), and C6-ceramide (5-25 μM) inhibited the cell viability, proliferation, and cytotoxicity in a dose-dependent manner. We observed that graphene oxide (GO), cisplatin (CIS), and C6-Ceramide (C6-Cer) stimulated acetylcholine esterase and neutral sphingomyelinase activity, total exosome protein concentration, and exosome counts associated with increased level of apoptosis, oxidative stress and endoplasmic reticulum stress. In contrast, GW4869 treatment inhibits biogenesis and release of exosomes. We observed that the human ovarian cancer cells secreted exosomes with typical cup-shaped morphology and surface protein biomarkers. The expression levels of TSG101, CD9, CD63, and CD81 were significantly higher in GO-treated cells than in control cells. Further, cytokine and chemokine levels were significantly higher in exosomes isolated from GO-treated SKOV3 cells than in those isolated from control cells. SKOV3 cells pre-treated with N-acetylcysteine or GW4869 displayed a significant reduction in GO-induced exosome biogenesis and release. Furthermore, endocytic inhibitors decrease exosome biogenesis and release by impairing endocytic pathways. This study identifies GO as a potential tool for targeting the exosome pathway and stimulating exosome biogenesis and release. We believe that the knowledge acquired in this study can be potentially extended to other exosome-dominated pathologies and model systems. Furthermore, these nanoparticles can provide a promising means to enhance exosome production in SKOV3 cells.

An optimized exosome production strategy for enhanced yield while without sacrificing cargo loading efficiency

BackgroundExosome mediated mRNA delivery is a promising strategy for the treatment of multiple diseases. However, the low yield of exosomes is a bottleneck for clinical translation. In this study, we boosted exosome production via simultaneously reducing the expression of genes inhibiting exosome biogenesis and supplementing the culture medium with red cell membrane components.ResultsAmong the candidate genes, knocking down of Rab4 was identified to have the highest efficacy in promoting exosome biogenesis while without any obvious cytotoxicity. Additionally, supplementing red cell membrane particles (RCMPs) in the culture medium further promoted exosome production. Combination of Rab4 knockdown and RCMP supplement increased exosome yield up to 14-fold. As a proof-of-concept study, low-density lipoprotein receptor (Ldlr) mRNA was forced expressed in the exosome donor cells and passively encapsulated into the exosomes during biogenesis with this strategy. Though exosome production per cell increased, the booster strategy didn’t alter the loading efficiency of therapeutic Ldlr mRNA per exosome. Consistently, the therapeutic exosomes derived by the strategy alleviated liver steatosis and atherosclerosis in Ldlr−/− mice, similar as the exosomes produced by routine methods.ConclusionsTogether, the proposed exosome booster strategy conquers the low yield bottleneck to some extent and would certainly facilitate the clinical translation of exosomes.

Exosomes as Anticancer Drug Delivery Vehicles: Prospects and Challenges.

Exosomes, a subset of extracellular vesicles, are widely present in various body fluids and are involved in mediating intercellular communication. They have received extensive attention as diagnostic markers. The excellent physicochemical and biological properties of exosomes make them great potential drug delivery vehicles for the treatment of cancer and other diseases. However, various challenges need to be addressed for the clinical application of exosomes. This review introduces the biogenesis and uptake of exosomes and compares different approaches for isolation and drug loading, focusing on the application and current challenges of exosomes as drug delivery vehicles in cancer therapy.

Krebs Memorial Fund 2022 awardees

Krebs Memorial Fund 2022 awardees

Effects of exosomes on tumor immunomodulation and their potential clinical applications (Review).

Exosomes are small extracellular vesicles containing proteins, nucleic acids and lipids, which can transmit information between cells, and can interfere with the epigenetic characteristics and functions of recipient cells. Tumor‑derived exosomes play a crucial role as communicators in the tumor microenvironment, and are involved in the occurrence and development of various tumors. The present review article summarizes the biogenesis of exosomes and their communication with local and remote cells, focusing on the function of tumor‑derived exosomes in the tumor microenvironment, including the promotion of angiogenesis, the induction of epithelial mesenchymal transformation, and the activation and inhibition of immune cells, as well as the effects of exosomes on the tumor microenvironment during microbial infections. Additionally, the effects of exosomes on tumor immunotherapy and the potential applications of exosomes as biomarkers, delivery vehicles and cancer vaccines in cancer diagnostics and therapeutics are discussed.

Enterovirus 71 non-structural protein 3A hijacks vacuolar protein sorting 25 to boost exosome biogenesis to facilitate viral replication.

Human enterovirus 71 (EV71) is one of the major agents of the hand, foot, and mouth disease (HFMD), and occasionally causes severe neurological complications. There is clinical evidence that EV71 infection increases the exosomes in the serum of severe HFMD patients, suggesting a role of exosomes in EV71 pathogenesis. However, the relationship between exosomes and EV71 replication remains elusive. In this study, we initially found that EV71 infection elevated exosome biogenesis in the cultured cells. Among EV71 non-structural proteins, we identified EV71 3A, but not 3B, constitutively promoted exosome secretion. In detail, EV71 3A protein interacted with vacuolar protein sorting 25 (VPS25), while knock-down of VPS25 reduced EV71 3A protein- and EV71-induced exosome production. Further studies revealed VPS25 located on exosomes and its expression correlated to the exosome production. During EV71 infection, knock-down of VPS25 decreased exosome biogenesis to attenuate viral replication. Consistently, GW4869, an exosome inhibitor, exerted an obviously antiviral activity against EV71 replication companied with the decrease of exosome secretion or formation. These findings suggest the binding of EV71 3A and VPS25 benefited exosome biogenesis, thereby boosting viral replication. This study uncovers a novel mechanism underlying EV71-mediated exosomes in the regulation of viral replication, which provides potential anti-viral strategies against the EV71 infection and transmission in HFMD.

307 (PB087) - Targeting the exosome biogenesis pathway to overcome daratumumab resistance in hematological cancers

Background: Daratumumab is a monoclonal antibody that targets CD38, which is highly expressed in lymphoid tumour cells. Daratumumab-based combinations have been incorporated as frontline therapy for multiple myeloma, and is well tolerated in clinical trials for other blood cancers. However, responses are heterogeneous and development of treatment resistance inevitable. Therefore, elucidation and targeting of mechanisms which can overcome daratumumab resistance is essential for the optimization of therapeutic response in patients.

Presence of Intact Hepatitis B Virions in Exosomes

Hepatitis B virus (HBV) was identified as an enveloped DNA virus with a diameter of 42 nm. Multivesicular bodies play a central role in HBV egress and exosome biogenesis. In light of this, it was studied whether intact virions wrapped in exosomes are released by HBV-producing cells. Robust methods for efficient separation of exosomes from virions were established. Exosomes were subjected to limited detergent treatment for release of viral particles. Electron microscopy of immunogold labeled ultrathin sections of purified exosomes was performed for characterization of exosomal HBV. Exosome formation/release was affected by inhibitors or Crispr/Cas-mediated gene silencing. Infectivity/uptake of exosomal HBV was investigated in susceptible and non-susceptible cells. Exosomes could be isolated from supernatants of HBV-producing cells, which are characterized by the presence of exosomal and HBV markers. These exosomal fractions could be separated from the fractions containing free virions. Limited detergent treatment of exosomes causes stepwise release of intact HBV virions and naked capsids. Inhibition of exosome morphogenesis impairs the release of exosome-wrapped HBV. Electron microscopy confirmed the presence of intact virions in exosomes. Moreover, the presence of large hepatitis B virus surface antigen on the surface of exosomes derived from HBV expressing cells was observed, which conferred exosome-encapsulated HBV initiating infection in susceptible cells in a , large hepatitis B virus surface antigen/Na+-taurocholate co-transporting polypeptide-dependent manner. The uptake of exosomal HBV with low efficiency was also observed in non-permissive cells. These data indicate that a fraction of intact HBV virions can be released as exosomes. This reveals a so far not described release pathway for HBV.

Biogenesis and release of endothelial extracellular vesicles: Morphological aspects

BackgroundCell-cell communication through extracellular vesicles (EVs) including exosomes, microvesicles and apoptotic bodies has been shown to be important in physiological homoeostasis as well as pathological processes such as atherosclerosis. However, while the cellular machinery controlling EV formation and composition has been studied during the past decade, less is known about the morphological process of their formation and release. MethodsUsing different electron microscopic approaches including transmission-, scanning-, immun-, and serial block face electron microscopy we studied the morphogenetic events of EV formation and release. We analysed the different steps of EV formation and release in cultured myocardial endothelial (MyEnd) and aortic endothelial (AoEnd) cell lines under serum starvation and under inflammatory conditions. ResultsWe show that in a narrow time frame, the number of active cells and microvesicle (MV) producing cells increased in dependence of time spent in cultivation and additional stimulation by TNF-α. However, MV secretion was a highly heterogeneous process which couldn´t be seen in all cells cultivated under the same conditions. Release of MVs could be observed all over the cells’ surface with no preferred release site. While no single specific microscopic approach applied was sufficient to provide a comprehensive analysis of EV biogenesis, we show that the limitations of one technique could be compensated by the qualities of the respective other applied techniques, thus enabling us to provide a detailed ultrastructural analysis of MV and exosome biogenesis. Surprisingly, exosome release in endothelial cells occurred via a yet undescribed process indicating that MVBs were incorporated into a novel distinct cellular compartment covered by fenestrated endothelium before exosome release. Lastly, we could show that TNF-α stimulation of AoEnd cells leads not only to the upregulation of CD44 in parental cells, but also to incorporation of CD44 into the membranes of generated MVs and exosomes. ConclusionsTaken together, our data contribute to a better understanding of biogenesis and release of EVs. We conclude that under inflammatory conditions, EVs can mediate the transfer of CD44 from endothelial cells to target cells at distant sites including vessel wall cells and this could be a mechanism by which MVs may change the and thus contribute to the development and progression of atherosclerotic lesions.

Hepatitis Viruses Control Host Immune Responses by Modifying the Exosomal Biogenesis Pathway and Cargo.

The development of smart immune evasion mechanisms is crucial for the establishment of acute and chronic viral hepatitis. Hepatitis is a major health problem worldwide arising from different causes, such as pathogens, metabolic disorders, and xenotoxins, with the five hepatitis viruses A, B, C, D, and E (HAV, HBV, HCV, HDV, and HEV) representing the majority of the cases. Most of the hepatitis viruses are considered enveloped. Recently, it was reported that the non-enveloped HAV and HEV are, in reality, quasi-enveloped viruses exploiting exosomal-like biogenesis mechanisms for budding. Regardless, all hepatitis viruses use exosomes to egress, regulate, and eventually escape from the host immune system, revealing another key function of exosomes apart from their recognised role in intercellular communication. This review will discuss how the hepatitis viruses exploit exosome biogenesis and transport capacity to establish successful infection and spread. Then, we will outline the contribution of exosomes in viral persistence and liver disease progression.

Exosome Release by Glucose Deprivation Is Important for the Viability of TSC-Null Cells.

The control of exosome release is associated with numerous physiological and pathological activities, and that release is often indicative of health, disease, and environmental nutrient stress. Tuberous sclerosis complex (TSC) regulates the cell viability via the negative regulation of the mammalian target of rapamycin complex (mTORC1) during glucose deprivation. However, the mechanism by which viability of TSC-null cells is regulated by mTORC1 inhibition under glucose deprivation remains unclear. Here, we demonstrated that exosome release regulates cell death induced by glucose deprivation in TSC-null cells. The mTORC1 inhibition by rapamycin significantly increased the exosome biogenesis, exosome secretion, and cell viability in TSC-null cells. In addition, the increase in cell viability by mTORC1 inhibition was attenuated by two different types of inhibitors of exosome release under glucose deprivation. Taken together, we suggest that exosome release inhibition might be a novel way for regression of cell growth in TSC-null cells showing lack of cell death by mTORC1 inhibition.

Composition, Biogenesis, and Role of Exosomes in Tumor Development.

The role of exosomes and their mechanism of action at the tumor site have received increasing attention. These microvesicles are produced by a wide range of cells including mesenchymal stem cells (MSCs) and immune cells. In particular, tumor cells release remarkable amounts of exosomes which spread to distant organs through the blood and enhance the possibility of tumor metastasis. In spite of results on tumor promoting properties, there are reports demonstrating the tumor inhibiting effects of exosomes depending on the type of the tumor and cell source. This review aims to have a comprehensive appraisal on the biogenesis, composition, and isolation of exosomes and then highlights the current knowledge of their role in cancer progression or inhibition by special focusing on MSC's exosomes (MSC-EXOs).

Membrane interaction to intercellular spread of pathology in Alzheimer's disease.

Progressive development of pathology is one of the major characteristic features of neurodegenerative diseases. Alzheimer’s disease (AD) is the most prevalent among them. Extracellular amyloid-β (Aβ) plaques and intracellular tau neurofibrillary tangles are the pathological phenotypes of AD. However, cellular and animal studies implicate tau as a secondary pathology in developing AD while Aβ aggregates is considered as a trigger point. Interaction of Aβ peptides with plasma membrane (PM) seems to be a promising site of involvement in the events that lead to AD. Aβ binding to the lipid membranes initiates formation of oligomers of Aβ species, and these oligomers are known as primary toxic agents for neuronal toxicities. Once initiated, neuropathological toxicities spread in a “prion-like” fashion probably through the mechanism of intercellular transfer of pathogenic aggregates. In the last two decades, several studies have demonstrated neuron-to-neuron transfer of neurodegenerative proteins including Aβ and tau via exosomes and tunneling nanotubes (TNTs), the two modes of long-range intercellular transfer. Emerging pieces of evidence indicate that molecular pathways related to the biogenesis of exosomes and TNTs interface with endo-lysosomal pathways and cellular signaling in connection to vesicle recycling-imposed PM and actin remodulation. In this review, we discuss interactions of Aβ aggregates at the membrane level and its implications in intercellular spread of pathogenic aggregates. Furthermore, we hypothesize how spread of pathogenic aggregates contributes to complex molecular events that could regulate pathological and synaptic changes related to AD.

Silver Nanoparticle Enhances Secretion of Exosomes in SH-SY5Y Cells: Potential Therapeutic Strategy for Human Neuroblastoma Cancer

Background: Exosomes-a subset of extracellular vesicles (EVs)-are secreted by virtually all cells, including human neuroblastoma cancer (SH-SY5Y) cells, into bodily fluids. Oxidative stress is critically involved in exosome biogenesis and release. Silver nanoparticles (AgNPs) induce cytotoxicity, oxidative stress, and apoptosis in cancer and non-cancer cells. Methods: Here, we studied whether AgNPs-induced oxidative stress could enhance exosome biogenesis and release under low serum conditions in the presence of AgNPs. Although several studies have reported various mechanisms that contribute to EV biogenesis and release from cells, none exists on the involvement of external stimuli by controlling acetylcholinesterase (AChE) and neutralsphingomyelinase (n-SMase) activities, total protein concentration of exosomes, and exosome count. Results: Owing to cytotoxic and oxidative stresses, AgNPs-treated cells and exosome release were significantly facilitated, which strongly correlated with the AgNPs-induced oxidative stress. Moreover, the expression levels of some important exosome biomarkers were found to be significant under oxidative stress conditions. N-acetylcysteine prevented oxidative stress-induced exosome biogenesis and release. Furthermore, we identified the involvement of the ceramide pathway in exosome functions by inhibiting AChE and n-SMase activities, and exosome protein/counts. These data contribute to the understanding of how AgNPs and intracellular molecular pathways affect exosome biogenesis and release in SH-SY5Y cells. Conclusion: To the best of our knowledge, this is the first study showing that AgNPs stimulate exosome biogenesis and release by inducing oxidative stress and ceramide pathways.