Quantitative Proteomic Analysis of Small and Large Extracellular Vesicles (EVs) Reveals Enrichment of Adhesion Proteins in Small EVs

Extracellular vesicle heterogeneity through the lens of multiomics

Extracellular vesicles (EVs) are heterogeneous in size, biogenesis, content, and function. Aggressive cancer cells release a distinct, poorly characterized, and particularly large EV subtype, namely large oncosomes (LOs). This study employs an optimized method to improve LO yields and integrates mass spectrometry and RNA sequencing (RNA-seq) to profile their molecular cargo. A consistent set of proteins enriched in LOs is identified across glioma, prostate, and breast cancer cell lines. These proteins are also present as mRNA in LOs from the prostate cancer model and are abundant in plasma LOs from 20 patients with metastasis. Single-LO RNA-seq confirms bulk LO cargo, demonstrating the utility of single-cell technologies for large vesicle analysis. Our patient study provides proof-of-principle evidence that we can use multiomics to delve into EV heterogeneity, biogenesis, and composition. It also suggests that plasma LOs help stratify patients, supporting their potential prognostic value for developing a multi-analyte approach for liquid biopsy.

Proteomic profiling of small extracellular vesicles from bovine nucleus pulposus cells

Small extracellular vesicles (small EV) are a conserved means of communication across the domains of life and lately gained more interest in mammalian non-cancerous work as non-cellular, biological therapeutic with encouraging results in recent studies of chronic degenerative diseases. The nucleus pulposus (NP) is the avascular and aneural center of an intervertebral disc (IVD), home to unique niche conditions and affected in IVD degeneration. We investigated autologous and mesenchymal stem cell (MSC) small EVs for their potential to contribute to cell and tissue homeostasis in the NP niche via mass spectrometric proteome and functional enrichment analysis using adult and fetal donors. We compared these findings to published small EV databases and MSC small EV data. We propose several mechanisms associated with NP small EVs: Membrane receptor trafficking to modify signal responses promoting niche homeostasis; Redox and energy homeostasis via metabolic enzymes delivery; Cell homeostasis via proteasome delivery and immunomodulation beyond an association with a serum protein corona. The proteome signature of small EVs generated by NP parent cells is similar to previously published small EV data, yet with a focus on supplementing anaerobic metabolism and redox balance while contributing to the maintenance of an aneural and avascular microniche.

Quantifying extracellular vesicle heterogeneity: the effect of process conditions on protein cargo for skin therapy

Extracellular vesicles (EVs) contain a variety of proteins with anti-inflammatory and immunomodulatory properties that offer promising benefits in skin therapy applications. An influx of EV proteomic studies in recent years has created the opportunity for a detailed comparison of EV heterogeneity between studies in the context of therapeutic applications. Although several process conditions are known to cause variability in EVs, little has been done to quantify the impact of these factors on the nature of EV protein cargo. This review aims to both compile publicly available EV proteomics data and quantitatively estimate. the impact of process conditions on protein cargo-particularly in the context of skin therapy applications. Of roughly 400 articles, 52 relevant proteomic studies were identified within the last 15 years. Across studies, 40% of the 13,000 observed proteins were identified in only a single study. EVs in general were found to be highly variable, with mixed effects models only able to account for 25-60% of variance when considering factors such as EV source, medium, isolation method, LC-MS ionization, and protein search algorithm. Overall, MSC-derived EVs contained a greater fraction of proteins within pathways associated with wound healing and skin therapy (immune system, hemostasis, extracellular matrix organization, and cellular response to stress) as well as the most number of unique proteins when compared to all other analysed EVs. Although EVs are a promising tool within skin therapeutics, the overall variability in protein cargo underscores the need for standardized methodologies to fully elucidate the impact of process conditions on EV cargo.

Multiomics from Alzheimer's Brains and Mesenchymal Stem Cell-Derived Extracellular Vesicles Identifies Therapeutic Potential of Specific Subpopulations to Target Mitochondrial Proteostasis

Background

Alzheimer's disease (AD) is characterized by complex molecular alterations that complicate its pathogenesis and contribute to the lack of effective treatments. Mesenchymal stem cell-derived extracellular vesicles (EVs) have shown promise in AD models, but results across different EV subpopulations remain inconsistent.

Objectives

This study investigates proteomic and transcriptomic data from publicly available postmortem AD brain datasets to identify molecular changes at both the gene and protein levels. These findings are then compared with the proteomes of various EV subpopulations, differing in size and distribution, to determine the most promising subtype for compensating molecular degeneration in AD.

Design

We conducted a comprehensive analysis of 788 brain samples, including 481 AD cases and 307 healthy controls, examining protein and mRNA levels to uncover AD-associated molecular changes. These findings were then compared with the proteomes of different EV subpopulations to identify potential therapeutic candidates.

Methods

A multi-omics approach was employed, integrating proteomic and transcriptomic data analysis, miRNA and transcription factor profiling, protein-protein network construction, hub gene identification, and enrichment analyses. This approach aimed to explore molecular changes in AD brains and pinpoint the most relevant EV subpopulations for therapeutic intervention.

Results

We identified common alterations in the cAMP signaling pathway and coagulation cascade at both the protein and mRNA levels. Distinct changes in energy metabolism were observed at the protein level but not at the mRNA level. A specific EV subtype, characterized by a broader size distribution obtained through high-speed centrifugation, was identified as capable of compensating for dysregulated mitochondrial proteostasis in AD brains. Network biology analyses further highlighted potential regulators of key therapeutic proteins within this EV subtype.

Conclusion

This study underscores the critical role of proteomic alterations in AD and identifies a promising EV subpopulation, enriched with proteins targeting mitochondrial proteostasis, as a potential therapeutic strategy for AD.

Exploring the Adhesion Properties of Extracellular Vesicles for Functional Assays

The ‛stickiness' of extracellular vesicles (EVs) can pose challenges for EV processing and storage, but adhesive properties may also be exploited to immobilise EVs directly on surfaces for various measurement techniques, including super-resolution microscopy (SRM). Direct adhesion to surfaces may allow the examination of broader populations of EVs than molecular affinity approaches, which can also involve specialised, expensive affinity reagents. Here, we report on the interaction of EVs with borosilicate glass and quartz coverslips and on the effects of pre-coating coverslips with poly-L-lysine (PLL), a reagent commonly used to facilitate interactions between negatively charged surfaces of cells and amorphous surfaces. Additionally, we compared two mounting media conditions for SRM imaging and used immobilised EVs for a B-cell interaction test. Our findings suggest that borosilicate glass coverslips immobilise EVs better than quartz glass coverslips. We also found that PLL is not strictly required for EV retention but contributes to the uniform distribution of EVs on borosilicate glass coverslips. Overall, these findings suggest that standard lab materials like borosilicate glass coverslips, with or without PLL, can be effectively used for the immobilisation of EVs in specific imaging techniques.

Human Brain Endothelial Cell-Derived Extracellular Vesicles Reduce Toxoplasma gondii Infection In Vitro in Human Brain and Umbilical Cord Vein Endothelial Cells

The endothelial layer, formed by endothelial cells, performs crucial functions in maintaining homeostasis. The endothelial integrity and function might be compromised due to various causes, including infection by Toxoplasma gondii, leading to an endothelial dysfunction. Toxoplasma gondii is an Apicomplexa parasite that infects a broad range of animals, including humans. This parasite can invade all nucleated cells, as well as endothelial cells. The interaction between this protozoan and endothelial cells can be mediated by different molecules, such as extracellular vesicles (EVs), which may either favor or hinder the infectious process. To investigate this interaction, we evaluated the infection of T. gondii on human brain microvascular endothelial cells (HBMEC) and human umbilical vein endothelial cells (HUVEC), in addition to assessing transcriptional changes. We also featured the EVs secreted by T. gondii and by infected and non-infected HBMEC and HUVEC. Finally, we evaluated the infection of cells stimulated with EVs of parasitic or cellular origin. Our results demonstrated that HUVEC not only exhibit a higher infection rate than HBMEC but also display a more pro-inflammatory transcriptional profile, with increased expression of interleukin-6 (IL6), interleukin-8 (IL8), and monocyte chemotactic protein-1 (MCP1) following infection. Additionally, we observed few differences in the concentration, distribution, and morphology of EVs secreted by both cell types, although their properties in modulating infection varied significantly. When cells were EVs stimulated, EVs from T. gondii promoted an increase in the HBMEC infection, EVs from infected or uninfected HBMEC reduced the infection, whereas EVs from HUVEC had no effect on the infectious process. In conclusion, our data indicate that T. gondii infection induces distinct changes in different endothelial cell types, and EVs from these cells can contribute to the resolution of the infection.

Exosomes derived from bone marrow mesenchymal stem cells ameliorate chemotherapeutically induced damage in rats' parotid salivary gland

OBJECTIVE

A nanometer-sized vesicles originating from bone marrow mesenchymal stem cells (BMMSCs), called exosomes, have been extensively recognized. This study defines the impact of BMMSCs and their derived exosomes on proliferation, apoptosis and oxidative stress (OS) levels of CP-induced parotid salivary gland damage.

METHODS

BMMSCs were isolated from the tibia of four white albino rats and further characterized by flowcytometric analysis. BMMSCs-derived exosomes were harvested and underwent characterization using transmission electron microscopy (TEM), western blot analysis and BCA assay. Fifty-six healthy white albino male rats weighting from 200 to 250 g were allocated into 4 groups (n = 14); Group I, rats received phosphate buffered saline (PBS), group II, rats were intraperitoneally injected with CP, group III& IV received CP and after 3 days they were intravenously injected with either BMMSCs (group III) or BMMSCs-exosomes (group IV). Histological, and immunohistochemical studies using proliferating cell nuclear antigen (PCNA) were done after 7 and 14 days. The OS was measured using malondialdehyde (MDA) and apoptosis was measured by annexin V-FITC/PI.

RESULTS

BMMSCs and exosomes treated groups showed better histological features approximating the normal architecture of the control group. The percentage of PCNA positively stained cells were significantly higher in the exosomes treated group in comparison to all other groups. MDA assay test revealed that the exosomes were able to reduce the OS when compared to the cell-based therapy using BMMSCs. Annexin V revealed that BMMSCs-exosomes significantly reduced the percentage of apoptotic cells compared to other treated groups.

CONCLUSIONS

BMMSCs-exosomes could improve the CP-induced cytotoxicity in rats' parotid salivary gland.

Biogenesis and functional implications of extracellular vesicles in cancer metastasis

Extracellular vesicles (EVs) play a crucial role in the complex process of cancer metastasis by facilitating cellular communication and influencing the microenvironment to promote the spread and establishment of cancer cells in distant locations. This paper explores the process of EV biogenesis, explaining their various sources that range from endosomal compartments to plasma membrane shedding. It also discusses the complex mechanisms that control the sorting of cargo within EVs, determining their chemical makeup. We investigate the several functions of EVs in promoting the spread of cancer to other parts of the body. These functions include influencing the immune system, creating environments that support the formation of metastases before they occur, and aiding in the transformation of cells from an epithelial to a mesenchymal state. Moreover, we explore the practical consequences of EV cargo, such as nucleic acids, proteins, and lipids, in influencing the spread of cancer cells, from the beginning of invasion to the creation of secondary tumor sites. Examining recent progress in the field of EV-based diagnostics and treatments, we explore the potential of EVs as highly promising biomarkers for predicting the course of cancer and as targets for therapeutic intervention. This review aims to provide a complete understanding of the biology of EVs in the context of cancer metastasis. By unravelling the nuances of EV biology, it seeks to pave the way for new tactics in cancer detection, treatment, and management.

Therapeutically Harnessing Tumor Cell-Derived Extracellular Vesicles for Multiple Myeloma: Recent Advances and Future Perspectives

Extracellular vesicles (EVs) have emerged as pivotal regulators for extensive intercellular crosstalk owing to capsuled diverse bioactive substances such as proteins, nucleic acids, and lipids. Recent studies have shown that tumor-derived EVs significantly influence the bone marrow microenvironment, contributing to the progression of multiple myeloma (MM). This highlights the robust potential of EVs as a promising avenue for developing more effective and precise diagnostic and therapeutic strategies for MM. In this review, we briefly discuss the multifaceted roles of EVs in MM progression, as well as the diagnostic and therapeutic value in MM management. Specifically, we focus on the latest research progress regarding the therapeutic potential of EVs for MM, particularly tumor cell-derived EVs, as we elaborate on three main aspects: (i) EVs as therapeutic targets, including the targeted inhibition of EV biogenesis and uptake, and the possibility of eliminating tumor-derived EVs; (ii) EVs as delivery nanovectors, where we discuss the latest anti-MM candidates and potential ways to optimize therapeutic efficiency; and (iii) engineered EVs as antitumor vaccines, focusing on the use of tumor cell-derived EVs in immunotherapy. Finally, we address the prospects and challenges of harnessing the therapeutic potential of EVs in clinical transformation.

The role of hepatocyte-derived extracellular vesicles in liver and extrahepatic diseases

Extracellular vesicles (EVs) are vesicle-like bodies with a double membrane structure that are released from the cell membrane or secreted by cells into the extracellular environment. These include exosomes, microvesicles, and apoptotic bodies. There is growing evidence indicating that the composition of liver cell contents changes following injury. The quantity of EVs and the biologically active substances they carry vary depending on the condition of the liver cells. Hepatocytes utilize EVs to modulate the functions of different liver cells and transfer them to distant organs via the systemic circulation, thereby playing a crucial role in intercellular communication. This review provides a concise overview of the research on the effects and potential mechanisms of hepatocyte-derived EVs (Hep-EVs) on liver diseases and extrahepatic diseases under different physiological and pathological conditions. Common liver diseases discussed include non-alcoholic fatty liver disease (NAFLD), viral hepatitis, alcoholic liver disease, drug-induced liver damage, and liver cancer. Given that NAFLD is the most prevalent chronic liver disease globally, this review particularly highlights the use of hepatocyte-derived EVs in NAFLD for disease progression, diagnosis, and treatment.

Exploring the adhesion properties of extracellular vesicles for functional assays

The "stickiness" of extracellular vesicles (EVs) can pose challenges for EV processing and storage, but adhesive properties may also be exploited to immobilize EVs directly on surfaces for various measurement techniques, including super-resolution microscopy. Direct adhesion to surfaces may allow examination of broader populations of EVs than molecular affinity approaches, which can also involve specialized, expensive affinity reagents. Here, we report on the interaction of EVs with borosilicate glass and quartz coverslips and on the effects of pre-coating coverslips with poly-L-lysine (PLL), a reagent commonly used to facilitate interactions between negatively charged surfaces of cells and amorphous surfaces. Additionally, we compared two mounting media conditions for super-resolution microscopy (SRM) imaging and used immobilized EVs for a B-cell interaction test. Our findings suggest that borosilicate glass coverslips immobilize EVs better than quartz glass coverslips. We also found that PLL is not strictly required for EV retention but contributes to the uniform distribution of EVs on borosilicate glass coverslips. Overall, these findings suggest that standard lab materials like borosilicate glass coverslips, with or without PLL, can be effectively used for the immobilization of EVs in specific imaging techniques.

A Machine Learning-Based Investigation of Integrin Expression Patterns in Cancer and Metastasis

Background

Integrins, a family of transmembrane receptor proteins, play complex roles in cancer development and metastasis. These roles could be better delineated through machine learning of transcriptomic data to reveal relationships between integrin expression patterns and cancer.

Methods

We collected publicly available RNA-Seq integrin expression from 8 healthy tissues and their corresponding tumors, along with data from metastatic breast cancer. We then used machine learning methods, including t-SNE visualization and Random Forest classification, to investigate changes in integrin expression patterns.

Results

Integrin expression varied across tissues and cancers, and between healthy and cancer samples from the same tissue, enabling the creation of models that classify samples by tissue or disease status. The integrins whose expression was important to these classifiers were identified. For example, ITGA7 was key to classification of breast samples by disease status. Analysis in breast tissue revealed that cancer rewires co-expression for most integrins, but the co-expression relationships of some integrins remain unchanged in healthy and cancer samples. Integrin expression in primary breast tumors differed from their metastases, with liver metastasis notably having reduced expression.

Conclusions

Integrin expression patterns vary widely across tissues and are greatly impacted by cancer. Machine learning of these patterns can effectively distinguish samples by tissue or disease status.

Nanoscale Extracellular Vesicle-Enabled Liquid Biopsy: Advances and Challenges for Lung Cancer Detection

Lung cancer is responsible for the death of over a million people worldwide every year. With its high mortality rate and exponentially growing number of new cases, lung cancer is a major threat to public health. The high mortality and poor survival rates of lung cancer patients can be attributed to its stealth progression and late diagnosis. For a long time, intrusive tissue biopsy has been considered the gold standard for lung cancer diagnosis and subtyping; however, the intrinsic limitations of tissue biopsy cannot be overlooked. In addition to being invasive and costly, it also suffers from limitations in sensitivity and specificity, is not suitable for repeated sampling, provides restricted information about the tumor and its molecular landscape, and is inaccessible in several cases. To cope with this, advancements in diagnostic technologies, such as liquid biopsy, have shown great prospects. Liquid biopsy is an innovative non-invasive approach in which cancer-related components called biomarkers are detected in body fluids, such as blood, urine, saliva and others. It offers a less invasive alternative with the potential for applications such as routine screening, predicting treatment outcomes, evaluating treatment effectiveness, detecting residual disease, or disease recurrence. A large number of research articles have indicated extracellular vesicles (EVs) as ideal biomarkers for liquid biopsy. EVs are a heterogeneous collection of membranous nanoparticles with diverse sizes, contents, and surface markers. EVs play a critical role in pathophysiological states and have gained prominence as diagnostic and prognostic biomarkers for multiple diseases, including lung cancer. In this review, we provide a detailed overview of the potential of EV-based liquid biopsy for lung cancer. Moreover, it highlights the strengths and weaknesses of various contemporary techniques for EV isolation and analysis in addition to the challenges that need to be addressed to ensure the widespread clinical application of EV-based liquid biopsies for lung cancer. In summary, EV-based liquid biopsies present interesting opportunities for the development of novel diagnostic and prognostic platforms for lung cancer, one of the most abundant cancers responsible for millions of cancer-related deaths worldwide.

Direct and cell-mediated EV-ECM interplay

Extracellular vesicles (EV) are a heterogeneous group of lipid particles excreted by cells. They play an important role in regeneration, development, inflammation, and cancer progression, together with the extracellular matrix (ECM), which they constantly interact with. In this review, we discuss direct and indirect interactions of EVs and the ECM and their impact on different physiological processes. The ECM affects the secretion of EVs, and the properties of the ECM and EVs modulate EVs' diffusion and adhesion. On the other hand, EVs can affect the ECM both directly through enzymes and indirectly through the modulation of the ECM synthesis and remodeling by cells. This review emphasizes recently discovered types of EVs bound to the ECM and isolated by enzymatic digestion, including matrix-bound nanovesicles (MBV) and tissue-derived EV (TiEV). In addition to the experimental studies, computer models of the EV-ECM-cell interactions, from all-atom models to quantitative pharmacology models aiming to improve our understanding of the interaction mechanisms, are also considered. STATEMENT OF SIGNIFICANCE: Application of extracellular vesicles in tissue engineering is an actively developing area. Vesicles not only affect cells themselves but also interact with the matrix and change it. The matrix also influences both cells and vesicles. In this review, different possible types of interactions between vesicles, matrix, and cells are discussed. Furthermore, the united EV-ECM system and its regulation through the cellular activity are presented.

The expression of PD-L1 on tumor-derived exosomes enhances infiltration and anti-tumor activity of αCD3 × αPD-L1 bispecific antibody-armed T cells

Anti-cluster of differentiation (CD) 3 × α programmed death-ligand 1 (PD-L1) bispecific T-cell engager (BsTE)-bound T-cells (BsTE:T) are a promising new cancer treatment agent. However, the mechanisms of action of bispecific antibody-armed activated T-cells are poorly understood. Therefore, this study aimed to investigate the anti-tumor mechanism and efficacy of BsTE:T. The BsTE:T migration was assessed in vivo and in vitro using syngeneic and xenogeneic tumor models, flow cytometry, immunofluorescence staining, transwell migration assays, microfluidic chips, Exo View R100, western blotting, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 technology. In murine B16 melanoma, MC38 colon cancer, and human multiple myeloma cells, BsTE:T exhibited superior tumor elimination relative to that of T-cells or BsTE alone. Moreover, BsTE:T migration into tumors was significantly enhanced owing to the presence of PD-L1 in tumor cells and secretion of PD-L1-containing exosomes. Furthermore, increased infiltration of CD44highCD62Llow effector memory CD8+ T-cells into tumors was closely associated with the anti-tumor effect of BsTE:T. Therefore, BsTE:T is an innovative potential anti-tumor therapy, and exosomal PD-L1 plays a crucial role both in vitro and in vivo in the anti-tumor activity of BsTE:T.

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

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

Extracellular vesicles from non-neuroendocrine SCLC cells promote adhesion and survival of neuroendocrine SCLC cells

Small cell lung cancer (SCLC) tumors are made up of distinct cell subpopulations, including neuroendocrine (NE) and non-neuroendocrine (non-NE) cells. While secreted factors from non-NE SCLC cells have been shown to support the growth of the NE cells, the underlying molecular factors are not well understood. Here, we show that exosome-type small extracellular vesicles (SEVs) secreted from non-NE SCLC cells promote adhesion and survival of NE SCLC cells. Proteomic analysis of purified SEVs revealed that extracellular matrix (ECM) proteins and integrins are highly enriched in SEVs of non-NE cells whereas nucleic acid-binding proteins are enriched in SEVs purified from NE cells. Addition of select purified ECM proteins identified in purified extracellular vesicles (EVs), specifically fibronectin, laminin 411, and laminin 511, were able to substitute for the role of non-NE-derived SEVs in promoting adhesion and survival of NE SCLC cells. Those same proteins were differentially expressed by human SCLC subtypes. These data suggest that ECM-carrying SEVs secreted by non-NE cells play a key role in supporting the growth and survival of NE SCLC cells.

Application of Multiomics Approach to Investigate the Therapeutic Potentials of Stem Cell-derived Extracellular Vesicle Subpopulations for Alzheimer's Disease

Alzheimer's disease (AD) presents a complex interplay of molecular alterations, yet understanding its pathogenesis remains a challenge. In this study, we delved into the intricate landscape of proteome and transcriptome changes in AD brains compared to healthy controls, examining 788 brain samples revealing common alterations at both protein and mRNA levels. Moreover, our analysis revealed distinct protein-level changes in aberrant energy metabolism pathways in AD brains that were not evident at the mRNA level. This suggests that the changes in protein expression could provide a deeper molecular representation of AD pathogenesis. Subsequently, using a comparative proteomic approach, we explored the therapeutic potential of mesenchymal stem cell-derived extracellular vehicles (EVs), isolated through various methods, in mitigating AD-associated changes at the protein level. Our analysis revealed a particular EV-subtype that can be utilized for compensating dysregulated mitochondrial proteostasis in the AD brain. By using network biology approaches, we further revealed the potential regulators of key therapeutic proteins. Overall, our study illuminates the significance of proteome alterations in AD pathogenesis and identifies the therapeutic promise of a specific EV subpopulation with reduced pro-inflammatory protein cargo and enriched proteins to target mitochondrial proteostasis.

A guide to the expanding field of extracellular vesicles and their release in regulated cell death programs

Homeostasis disruption is visible at the molecular and cellular levels and may often lead to cell death. This vital process allows us to maintain the more extensive system's integrity by keeping the different features (genetic, metabolic, physiologic, and individual) intact. Interestingly, while cells can die in different manners, dying cells still communicate with their environment. This communication was, for a long time, perceived as only driven by the release of soluble factors. However, it has now been reconsidered with the increasing interest in extracellular vesicles (EVs), which are discovered to be released during different regulated cell death programs, with the observation of specific effects. EVs are game changers in the paradigm of cell-cell communication with tremendous implications in fundamental research with regard to noncell autonomous functions, as well as in biomarkers research, all of which are geared toward diagnostic and therapeutic purposes. This review is composed of two main parts. The first is a comprehensive presentation of the state of the art of the EV field at large. In the second part, we focus on EVs discovered to be released during different regulated cell death programs, also known as cell death EVs (cdEVs), and EV-associated specific effects on recipient cells in the context of cell death and inflammation/inflammatory responses.

Unraveling the Impact of Extracellular Vesicle-Depleted Serum on Endothelial Cell Characteristics over Time

Extracellular vesicles (EVs) are produced by all kinds of cells, including endothelial cells. It has been observed that EVs present in fetal bovine serum (FBS), broadly used in cell culture, can be a confounding factor and lead to misinterpretation of results. To investigate this phenomenon, human brain microvascular endothelial cells (HBMECs) were cultured for 2 or 24 h in the presence of EV-depleted FBS (EVdS). Cell death, gene and protein expression, and the presence of EVs isolated from these cells were evaluated. The uptake of EVs, intercellular adhesion molecule 1 (ICAM-1) expression, and monocyte adhesion to endothelial cells exposed to EVs were also evaluated. Our results revealed higher apoptosis rates in cells cultured with EVdS for 2 and 24 h. There was an increase in interleukin 8 (IL8) expression after 2 h and a decrease in interleukin 6 (IL6) and IL8 expression after 24 h of culture. Among the proteins identified in EVs isolated from cells cultured for 2 h (EV2h), several were related to ribosomes and carbon metabolism. EVs from cells cultured for 24 h (EV24h) presented a protein profile associated with cell adhesion and platelet activation. Additionally, HBMECs exhibited increased uptake of EV2h. Treatment of endothelial cells with EV2h resulted in greater ICAM-1 expression and greater adherence to monocytes than did treatment with EV24h. According to our data, HBMEC cultivated with EVdS produce EVs with different physical characteristics and protein levels that vary over time.

Mammalian orthoreovirus can exit cells in extracellular vesicles

Several egress pathways have been defined for many viruses. Among these pathways, extracellular vesicles (EVs) have been shown to function as vehicles of non-lytic viral egress. EVs are heterogenous populations of membrane-bound structures released from cells as a form of intercellular communication. EV-mediated viral egress may enable immune evasion and collective viral transport. Strains of nonenveloped mammalian orthoreovirus (reovirus) differ in cell lysis phenotypes, with T3D disrupting cell membranes more efficiently than T1L. However, mechanisms of reovirus egress and the influence of transport strategy on infection are only partially understood. To elucidate reovirus egress mechanisms, we infected murine fibroblasts (L cells) and non-polarized human colon epithelial (Caco-2) cells with T1L or T3D reovirus and enriched cell culture supernatants for large EVs, medium EVs, small EVs, and free reovirus. We found that both reovirus strains exit cells in association with large and medium EVs and as free virus particles, and that EV-enriched fractions are infectious. While reovirus visually associates with large and medium EVs, only medium EVs offer protection from antibody-mediated neutralization. EV-mediated protection from neutralization is virus strain- and cell type-specific, as medium EVs enriched from L cell supernatants protect T1L and T3D, while medium EVs enriched from Caco-2 cell supernatants largely fail to protect T3D and only protect T1L efficiently. Using genetically barcoded reovirus, we provide evidence that large and medium EVs can convey multiple particles to recipient cells. Finally, T1L or T3D infection increases the release of all EV sizes from L cells. Together, these findings suggest that in addition to exiting cells as free particles, reovirus promotes egress from distinct cell types in association with large and medium EVs during lytic or non-lytic infection, a mode of exit that can mediate multiparticle infection and, in some cases, protection from antibody neutralization.

RAB31 in glioma-derived endothelial cells promotes glioma cell invasion via extracellular vesicle-mediated enrichment of MYO1C

Extracellular vesicles (EV), important messengers in intercellular communication, can load and transport various bioactive components and participate in different biological processes. We previously isolated glioma human endothelial cells (GhECs) and found that GhECs, rather than normal human brain endothelial cells (NhECs), exhibit specific enrichment of MYO1C into EVs and promote the migration of glioma cells. In this study, we explored the mechanism by which MYO1C is secreted into EVs. We report that such secretion is dependent on RAB31, RAB27B, and FAS. When expression of RAB31 increases, MYO1C is enriched in secretory EVs. Finally, we identified an EV export mechanism for MYO1C that promotes glioma cell invasion and is dependent on RAB31 in GhECs. In summary, our data indicate that the knockdown of RAB31 can reduce enrichment of MYO1C in extracellular vesicles, thereby attenuating the promotion of glioma cell invasion by GhEC-EVs.

Islet cells in human type 1 diabetes: from recent advances to novel therapies - a symposium-based roadmap for future research

There is a growing understanding that the early phases of type 1 diabetes (T1D) are characterised by a deleterious dialogue between the pancreatic beta cells and the immune system. This, combined with the urgent need to better translate this growing knowledge into novel therapies, provided the background for the JDRF-DiabetesUK-INNODIA-nPOD symposium entitled 'Islet cells in human T1D: from recent advances to novel therapies', which took place in Stockholm, Sweden, in September 2022. We provide in this article an overview of the main themes addressed in the symposium, pointing to both promising conclusions and key unmet needs that remain to be addressed in order to achieve better approaches to prevent or reverse T1D.

Mammalian orthoreovirus can exit cells in extracellular vesicles

Several egress pathways have been defined for many viruses. Among these pathways, extracellular vesicles (EVs) have been shown to function as vehicles of non-lytic viral egress. EVs are heterogenous populations of membrane-bound structures released from cells as a form of intercellular communication. EV-mediated viral egress may enable immune evasion and collective viral transport. Strains of nonenveloped mammalian orthoreovirus (reovirus) differ in cell lysis phenotypes, with T3D disrupting cell membranes more efficiently than T1L. However, mechanisms of reovirus egress and the influence of transport strategy on infection are only partially understood. To elucidate reovirus egress mechanisms, we infected murine fibroblasts (L cells) and non-polarized human colon epithelial (Caco-2) cells with T1L or T3D reovirus and enriched cell culture supernatants for large EVs, medium EVs, small EVs, and free reovirus. We found that both reovirus strains exit cells in association with large and medium EVs and as free virus particles, and that EV-enriched fractions are infectious. While reovirus visually associates with large and medium EVs, only medium EVs offer protection from antibody-mediated neutralization. EV-mediated protection from neutralization is virus strain- and cell type-specific, as medium EVs enriched from L cell supernatants protect T1L and T3D, while medium EVs enriched from Caco-2 cell supernatants largely fail to protect T3D and only protect T1L efficiently. Using genetically barcoded reovirus, we provide evidence that large and medium EVs can convey multiple particles to recipient cells. Finally, T1L or T3D infection increases the release of all EV sizes from L cells. Together, these findings suggest that in addition to exiting cells as free particles, reovirus promotes egress from distinct cell types in association with large and medium EVs during lytic or non-lytic infection, a mode of exit that can mediate multiparticle infection and, in some cases, protection from antibody neutralization.

New Gene Markers of Exosomal Regulation Are Involved in Porcine Granulosa Cell Adhesion, Migration, and Proliferation

Exosomal regulation is intimately involved in key cellular processes, such as migration, proliferation, and adhesion. By participating in the regulation of basic mechanisms, extracellular vesicles are important in intercellular signaling and the functioning of the mammalian reproductive system. The complexity of intercellular interactions in the ovarian follicle is also based on multilevel intercellular signaling, including the mechanisms involving cadherins, integrins, and the extracellular matrix. The processes in the ovary leading to the formation of a fertilization-ready oocyte are extremely complex at the molecular level and depend on the oocyte's ongoing relationship with granulosa cells. An analysis of gene expression from material obtained from a primary in vitro culture of porcine granulosa cells was employed using microarray technology. Genes with the highest expression (LIPG, HSD3B1, CLIP4, LOX, ANKRD1, FMOD, SHAS2, TAGLN, ITGA8, MXRA5, and NEXN) and the lowest expression levels (DAPL1, HSD17B1, SNX31, FST, NEBL, CXCL10, RGS2, MAL2, IHH, and TRIB2) were selected for further analysis. The gene expression results obtained from the microarrays were validated using quantitative RT-qPCR. Exosomes may play important roles regarding intercellular signaling between granulosa cells. Therefore, exosomes may have significant applications in regenerative medicine, targeted therapy, and assisted reproduction technologies.

Convection and extracellular matrix binding control interstitial transport of extracellular vesicles

Extracellular vesicles (EVs) influence a host of normal and pathophysiological processes in vivo. Compared to soluble mediators, EVs can traffic a wide range of proteins on their surface including extracellular matrix (ECM) binding proteins, and their large size (∼30-150 nm) limits diffusion. We isolated EVs from the MCF10 series-a model human cell line of breast cancer progression-and demonstrated increasing presence of laminin-binding integrins α3β1 and α6β1 on the EVs as the malignant potential of the MCF10 cells increased. Transport of the EVs within a microfluidic device under controlled physiological interstitial flow (0.15-0.75 μm/s) demonstrated that convection was the dominant mechanism of transport. Binding of the EVs to the ECM enhanced the spatial concentration and gradient, which was mitigated by blocking integrins α3β1 and α6β1. Our studies demonstrate that convection and ECM binding are the dominant mechanisms controlling EV interstitial transport and should be leveraged in nanotherapeutic design.

Quantitative Proteomics for the Identification of Differentially Expressed Proteins in the Extracellular Vesicles of Cervical Cancer Cells

The extracellular vesicles (EVs) in a tumoral microenvironment can exert different functions by transferring their content, which has been poorly described in cervical cancer. Here, we tried to clarify the proteomic content of these EVs, comparing those derived from cancerous HPV (+) keratinocytes (HeLa) versus those derived from normal HPV (-) keratinocytes (HaCaT). We performed a quantitative proteomic analysis, using LC-MS/MS, of the EVs from HeLa and HaCaT cell lines. The up- and downregulated proteins in the EVs from the HeLa cell line were established, along with the cellular component, molecular function, biological processes, and signaling pathways in which they participate. The biological processes with the highest number of upregulated proteins are cell adhesion, proteolysis, lipid metabolic process, and immune system processes. Interestingly, three of the top five signaling pathways with more up- and downregulated proteins are part of the immune response. Due to their content, we can infer that EVs can have a significant role in migration, invasion, metastasis, and the activation or suppression of immune system cells in cancer.

A guide to mass spectrometric analysis of extracellular vesicle proteins for biomarker discovery

Exosomes (small extracellular vesicles) in living organisms play an important role in processes such as cell proliferation or intercellular communication. Recently, exosomes have been extensively investigated for biomarker discoveries for various diseases. An important aspect of exosome analysis involves the development of enrichment methods that have been introduced for successful isolation of exosomes. These methods include ultracentrifugation, size exclusion chromatography, polyethylene glycol-based precipitation, immunoaffinity-based enrichment, ultrafiltration, and asymmetric flow field-flow fractionation among others. To confirm the presence of exosomes, various characterization methods have been utilized such as Western blot analysis, atomic force microscopy, electron microscopy, optical methods, zeta potential, visual inspection, and mass spectrometry. Recent advances in high-resolution separations, high-performance mass spectrometry and comprehensive proteome databases have all contributed to the successful analysis of exosomes from patient samples. Herein we review various exosome enrichment methods, characterization methods, and recent trends of exosome investigations using mass spectrometry-based approaches for biomarker discovery.

The Proteome of Large or Small Extracellular Vesicles in Pig Seminal Plasma Differs, Defining Sources and Biological Functions

Seminal plasma contains many morphologically heterogeneous extracellular vesicles (sEVs). These are sequentially released by cells of the testis, epididymis, and accessory sex glands and involved in male and female reproductive processes. This study aimed to define in depth sEV subsets isolated by ultrafiltration and size exclusion chromatography, decode their proteomic profiles using liquid chromatography-tandem mass spectrometry, and quantify identified proteins using sequential window acquisition of all theoretical mass spectra. The sEV subsets were defined as large (L-EVs) or small (S-EVs) by their protein concentration, morphology, size distribution, and EV-specific protein markers and purity. Liquid chromatography-tandem mass spectrometry identified a total of 1034 proteins, 737 of them quantified by SWATH in S-EVs, L-EVs, and non-EVs-enriched samples (18-20 size exclusion chromatography-eluted fractions). The differential expression analysis revealed 197 differentially abundant proteins between both EV subsets, S-EVs and L-EVs, and 37 and 199 between S-EVs and L-EVs versus non-EVs-enriched samples, respectively. The gene ontology enrichment analysis of differentially abundant proteins suggested, based on the type of protein detected, that S-EVs could be mainly released through an apocrine blebbing pathway and be involved in modulating the immune environment of the female reproductive tract as well as during sperm-oocyte interaction. In contrast, L-EVs could be released by fusion of multivesicular bodies with the plasma membrane becoming involved in sperm physiological processes, such as capacitation and avoidance of oxidative stress. In conclusion, this study provides a procedure capable of isolating subsets of EVs from pig seminal plasma with a high degree of purity and shows differences in the proteomic profile between EV subsets, indicating different sources and biological functions for the sEVs.

Lipopolysaccharide Primes Human Macrophages for Noncanonical Inflammasome-Induced Extracellular Vesicle Secretion

Human macrophages secrete extracellular vesicles (EVs) loaded with numerous immunoregulatory proteins. Vesicle-mediated protein secretion in macrophages is regulated by poorly characterized mechanisms; however, it is now known that inflammatory conditions significantly alter both the quantities and protein composition of secreted vesicles. In this study, we employed high-throughput quantitative proteomics to characterize the modulation of EV-mediated protein secretion during noncanonical caspase-4/5 inflammasome activation via LPS transfection. We show that human macrophages activate robust caspase-4-dependent EV secretion upon transfection of LPS, and this process is also partially dependent on NLRP3 and caspase-5. A similar effect occurs with delivery of the LPS with Escherichia coli-derived outer membrane vesicles. Moreover, sensitization of the macrophages through TLR4 by LPS priming prior to LPS transfection dramatically augments the EV-mediated protein secretion. Our data demonstrate that this process differs significantly from canonical inflammasome activator ATP-induced vesiculation, and it is dependent on the autocrine IFN signal associated with TLR4 activation. LPS priming preceding the noncanonical inflammasome activation significantly enhances vesicle-mediated secretion of inflammasome components caspase-1, ASC, and lytic cell death effectors GSDMD, MLKL, and NINJ1, suggesting that inflammatory EV transfer may exert paracrine effects in recipient cells. Moreover, using bioinformatics methods, we identify 15-deoxy-Δ12,14-PGJ2 and parthenolide as inhibitors of caspase-4-mediated inflammation and vesicle secretion, indicating new therapeutic potential of these anti-inflammatory drugs.

The Roles of Exosomes in the Diagnose, Development and Therapeutic Resistance of Oral Squamous Cell Carcinoma

Oral cancer is one of the most common cancers worldwide, of which more than half of patients are diagnosed at a locally advanced stage with poor prognosis due to recurrence, metastasis and resistant to treatment. Thus, it is imperative to further explore the potential mechanism of development and drug resistance of oral cancer. Exosomes are small endosome-derived lipid nanoparticles that are released by cells. Since the cargoes of exosomes were inherited from their donor cells, the cargo profiles of exosomes can well recapitulate that of their donor cells. This is the theoretical basis of exosome-based liquid biopsy, providing a tool for early diagnosis of oral cancer. As an important intracellular bioactive cargo delivery vector, exosomes play a critical role in the development of oral cancer by transferring their cargoes to receipt cells. More importantly, recent studies have revealed that exosomes could induce therapy-resistance in oral cancer through multiple ways, including exosome-mediated drug efflux. In this review, we summarize and compare the role of exosomes in the diagnosis, development and therapy-resistant of oral cancer. We also highlight the clinical application of exosomes, and discuss the advantages and challenges of exosomes serving as predictive biomarker, therapy target and therapy vector in oral cancer.

Exosome-Based Cell Homing and Angiogenic Differentiation for Dental Pulp Regeneration

Exosomes have attracted attention due to their ability to promote intercellular communication leading to enhanced cell recruitment, lineage-specific differentiation, and tissue regeneration. The object of this study was to determine the effect of exosomes on cell homing and angiogenic differentiation for pulp regeneration. Exosomes (DPSC-Exos) were isolated from rabbit dental pulp stem cells cultured under a growth (Exo-G) or angiogenic differentiation (Exo-A) condition. The characterization of exosomes was confirmed by nanoparticle tracking analysis and an antibody array. DPSC-Exos significantly promoted cell proliferation and migration when treated with 5 × 108/mL exosomes. In gene expression analysis, DPSC-Exos enhanced the expression of angiogenic markers including vascular endothelial growth factor A (VEGFA), Fms-related tyrosine kinase 1 (FLT1), and platelet and endothelial cell adhesion molecule 1 (PECAM1). Moreover, we identified key exosomal microRNAs in Exo-A for cell homing and angiogenesis. In conclusion, the exosome-based cell homing and angiogenic differentiation strategy has significant therapeutic potential for pulp regeneration.

Extracellular Vesicle Antibody Microarray for Multiplexed Inner and Outer Protein Analysis

Proteins are found both outside and inside of extracellular vesicles (EVs) and govern the properties and functions of EVs, while also constituting a signature of the cell of origin and of biological function and disease. Outer proteins on EVs can be directly bound by antibodies to either enrich EVs, or probe the expression of a protein on EVs, including in a combinatorial manner. However, co-profiling of inner proteins remains challenging. Here, we present the high-throughput, multiplexed analysis of EV inner and outer proteins (EVPio). We describe the optimization of fixation and heat-induced protein epitope retrieval for EVs, along with oligo-barcoded antibodies and branched DNA signal amplification for sensitive, multiplexed, and high-throughput assays. We captured four subpopulations of EVs from colorectal cancer (CRC) cell lines HT29 and SW403 based on EpCAM, CD9, CD63, and CD81 expression, and quantified the co-expression of eight outer [integrins (ITGs) and tetraspanins] and four inner (heat shock, endosomal, and inner leaflet) proteins. The differences in co-expression patterns were consistent with the literature and known biological function. In conclusion, EVPio analysis can simultaneously detect multiple inner and outer proteins in EVs immobilized on a surface, opening the way to extensive combinatorial protein profiles for both discovery and clinical translation.

Extracellular vesicles released upon stimulation with antiphospholipid antibodies: An actual direct procoagulant mechanism or a new factor in the lupus anticoagulant paradox?

Antiphospholipid antibodies (aPL) lead to a hypercoagulable state in vivo. Paradoxically, some of these autoantibodies perform as inhibitors of the coagulation cascade in vitro (a phenomenon referred to as "lupus anticoagulant"). The presence of lupus anticoagulant has been related to an increased quantity of plasma extracellular vesicles, which may constitute a direct procoagulant mechanism in antiphospholipid syndrome. This study investigates whether or not endothelial cell-derived extracellular vesicles released upon stimulation with aPL (aPL-EDEVs) are related to a higher direct coagulation activity. Using an in vitro model of endothelium, flow cytometry and a recalcified plasma-based assay, we found that the coagulation activity of aPL-EDEVs is mainly conditioned by the lupus anticoagulant-like activity of autoantibodies. Nevertheless, in the presence of β2 glycoprotein I, a cofactor of aPL during the stimulation of endothelial cells, the coagulation activity of EDEVs is restored in a mitogen-activated protein kinase kinases 1 and 2 (MEK1/2)-dependent manner. This phenomenon was especially evident when using immunoglobulins G from patients with vascular and obstetric primary antiphospholipid syndrome who manifest refractoriness to treatment. Our findings suggest that the role of aPL-EDEVs in the antiphospholipid syndrome-related hypercoagulable state may not rely on their capacity to enhance clotting directly. While β2 glycoprotein I performs as a procoagulant cofactor and restores the coagulation activity of extracellular vesicles via MEK1/2 pathway, proportionally, autoantibodies interact with aPL-EDEVs and exhaust their coagulation properties. Further analysis is required to establish whether lupus anticoagulant-like autoantibodies opsonise extracellular vesicles and whether opsonised vesicles may lead to thrombosis by indirect means.

Inflammatory Cytokines Rewire the Proinsulin Interaction Network in Human Islets

CONTEXT

Aberrant biosynthesis and secretion of the insulin precursor proinsulin occurs in both type I and type II diabetes. Inflammatory cytokines are implicated in pancreatic islet stress and dysfunction in both forms of diabetes, but the mechanisms remain unclear.

OBJECTIVE

We sought to determine the effect of the diabetes-associated cytokines on proinsulin folding, trafficking, secretion, and β-cell function.

METHODS

Human islets were treated with interleukin-1β and interferon-γ for 48 hours, followed by analysis of interleukin-6, nitrite, proinsulin and insulin release, RNA sequencing, and unbiased profiling of the proinsulin interactome by affinity purification-mass spectrometry.

RESULTS

Cytokine treatment induced secretion of interleukin-6, nitrites, and insulin, as well as aberrant release of proinsulin. RNA sequencing showed that cytokines upregulated genes involved in endoplasmic reticulum stress, and, consistent with this, affinity purification-mass spectrometry revealed cytokine induced proinsulin binding to multiple endoplasmic reticulum chaperones and oxidoreductases. Moreover, increased binding to the chaperone immunoglobulin binding protein was required to maintain proper proinsulin folding in the inflammatory environment. Cytokines also regulated novel interactions between proinsulin and type 1 and type 2 diabetes genome-wide association studies candidate proteins not previously known to interact with proinsulin (eg, Ataxin-2). Finally, cytokines induced proinsulin interactions with a cluster of microtubule motor proteins and chemical destabilization of microtubules with Nocodazole exacerbated cytokine induced proinsulin secretion.

CONCLUSION

Together, the data shed new light on mechanisms by which diabetes-associated cytokines dysregulate β-cell function. For the first time, we show that even short-term exposure to an inflammatory environment reshapes proinsulin interactions with critical chaperones and regulators of the secretory pathway.

Inside the β Cell: Molecular Stress Response Pathways in Diabetes Pathogenesis

The pathogeneses of the 2 major forms of diabetes, type 1 and type 2, differ with respect to their major molecular insults (loss of immune tolerance and onset of tissue insulin resistance, respectively). However, evidence suggests that dysfunction and/or death of insulin-producing β-cells is common to virtually all forms of diabetes. Although the mechanisms underlying β-cell dysfunction remain incompletely characterized, recent years have witnessed major advances in our understanding of the molecular pathways that contribute to the demise of the β-cell. Cellular and environmental factors contribute to β-cell dysfunction/loss through the activation of molecular pathways that exacerbate endoplasmic reticulum stress, the integrated stress response, oxidative stress, and impaired autophagy. Whereas many of these stress responsive pathways are interconnected, their individual contributions to glucose homeostasis and β-cell health have been elucidated through the development and interrogation of animal models. In these studies, genetic models and pharmacological compounds have enabled the identification of genes and proteins specifically involved in β-cell dysfunction during diabetes pathogenesis. Here, we review the critical stress response pathways that are activated in β cells in the context of the animal models.

Seminal extracellular vesicles subsets modulate gene expression in cumulus cells of porcine in vitro matured oocytes

Seminal plasma (SP), a fluid composed mainly by secretions from accessory sex glands, contains a heterogenous population of extracellular vesicles (EVs), involved in several reproductive physiological processes. Seminal plasma has been found to modulate ovary function, in terms of hormone secretion and immune regulation. This study evaluated the potential effect of SP-EV-subsets on the modulation of cumulus-oocyte-complex (COCs) physiology during in vitro maturation (IVM). Two SP-EV-subsets, small-EVs (S-EVs) and large-EVs (L-EVs), were isolated from pig SP by size-exclusion-chromatography. Next, COCs were IVM in the absence (control) or presence of each SP-EV-subset to evaluate their uptake by COCs (PKH67-EVs labelling) and their effect on oocyte and cumulus cells (CCs) (gene expression, and progesterone and estradiol-17β levels). S-EVs and L-EVs were able to bind CCs but not oocytes. Supplementation with L-EVs induced changes (P ≤ 0.05) in the transcript levels of oocyte maturation- (HAS2) and steroidogenesis-related genes (CYP11A1 and HSD3B1) in CCs. No effect on nuclear oocyte maturation and progesterone and estradiol-17β levels was observed when COCs were IVM with any of the two SP-EV-subsets. In conclusion, while SP-EV-subsets can be integrated by CCs during IVM, they do not affect oocyte maturation and only L-EVs are able to modulate CCs function, mainly modifying the expression of steroidogenesis-related genes.

Counts of hyaluronic acid-containing extracellular vesicles decrease in naturally occurring equine osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease with inadequately understood pathogenesis leading to pain and functional limitations. Extracellular vesicles (EVs) released by synovial joint cells can induce both pro- and anti-OA effects. Hyaluronic acid (HA) lubricates the surfaces of articular cartilage and is one of the bioactive molecules transported by EVs. In humans, altered EV counts and composition can be observed in OA synovial fluid (SF), while EV research is in early stages in the horse-a well-recognized OA model. The aim was to characterize SF EVs and their HA cargo in 19 horses. SF was collected after euthanasia from control, OA, and contralateral metacarpophalangeal joints. The SF HA concentrations and size distribution were determined with a sandwich-type enzyme-linked sorbent assay and size-exclusion chromatography. Ultracentrifugation followed by nanoparticle tracking analysis (NTA) were utilized to quantify small EVs, while confocal laser scanning microscopy (CLSM) and image analysis characterized larger EVs. The number and size distribution of small EVs measured by NTA were unaffected by OA, but these results may be limited by the lack of hyaluronidase pre-treatment of the samples. When visualized by CLSM, the number and proportion of larger HA-containing EVs (HA-EVs) decreased in OA SF (generalized linear model, count: p = 0.024, %: p = 0.028). There was an inverse association between the OA grade and total EV count, HA-EV count, and HA-EV % (r_s = - 0.264 to - 0.327, p = 0.012-0.045). The total HA concentrations were also lower in OA (generalized linear model, p = 0.002). To conclude, the present study discovered a potential SF biomarker (HA-EVs) for naturally occurring equine OA. The roles of HA-EVs in the pathogenesis of OA and their potential as a joint disease biomarker and therapeutic target warrant future studies.

Extracellular vesicles in β cell biology: Role of lipids in vesicle biogenesis, cargo, and intercellular signaling

BACKGROUND

Type 1 diabetes (T1D) is a complex autoimmune disorder whose pathogenesis involves an intricate interplay between β cells of the pancreatic islet, other islet cells, and cells of the immune system. Direct intercellular communication within the islet occurs via cell surface proteins and indirect intercellular communication has traditionally been seen as occurring via secreted proteins (e.g., endocrine hormones and cytokines). However, recent literature suggests that extracellular vesicles (EVs) secreted by β cells constitute an additional and biologically important mechanism for transmitting signals to within the islet.

SCOPE OF REVIEW

This review summarizes the general mechanisms of EV formation, with a particular focus on how lipids and lipid signaling pathways influence their formation and cargo. We review the implications of EV release from β cells for T1D pathogenesis, how EVs and their cargo might be leveraged as biomarkers of this process, and how EVs might be engineered as a therapeutic candidate to counter T1D outcomes.

MAJOR CONCLUSIONS

Islet β cells have been viewed as initiators and propagators of the cellular circuit giving rise to autoimmunity in T1D. In this context, emerging literature suggests that EVs may represent a conduit for communication that holds more comprehensive messaging about the β cells from which they arise. As the field of EV biology advances, it opens the possibility that intervening with EV formation and cargo loading could be a novel disease-modifying approach in T1D.

Engineering extracellular vesicles by three-dimensional dynamic culture of human mesenchymal stem cells

Human mesenchymal stem cell (hMSC) derived extracellular vesicles (EVs) have shown therapeutic potential in recent studies. However, the corresponding therapeutic components are largely unknown, and scale-up production of hMSC EVs is a major challenge for translational applications. In the current study, hMSCs were grown as 3D aggregates under wave motion to promote EV secretion. Results demonstrate that 3D hMSC aggregates promote activation of the endosomal sorting complexes required for transport (ESCRT)-dependent and -independent pathways. mRNA sequencing revealed global transcriptome alterations for 3D hMSC aggregates. Compared to 2D-hMSC-EVs, the quantity of 3D-hMSC-EVs was enhanced significantly (by 2-fold), with smaller sizes, higher miR-21 and miR-22 expression, and an altered protein cargo (e.g., upregulation of cytokines and anti-inflammatory factors) uncovered by proteomics analysis, possibly due to altered EV biogenesis. Functionally, 3D-hMSC-EVs rejuvenated senescent stem cells and exhibited enhanced immunomodulatory potentials. In summary, this study provides a promising strategy for scalable production of high-quality EVs from hMSCs with enhanced therapeutic potential.

Fatty Acid Fingerprints and Hyaluronic Acid in Extracellular Vesicles from Proliferating Human Fibroblast-like Synoviocytes

Extracellular vesicles (EVs) function as conveyors of fatty acids (FAs) and other bioactive lipids and can modulate the gene expression and behavior of target cells. EV lipid composition influences the fluidity and stability of EV membranes and reflects the availability of lipid mediator precursors. Fibroblast-like synoviocytes (FLSs) secrete EVs that transport hyaluronic acid (HA). FLSs play a central role in inflammation, pannus formation, and cartilage degradation in joint diseases, and EVs have recently emerged as potential mediators of these effects. The aim of the present study was to follow temporal changes in HA and EV secretion by normal FLSs, and to characterize the FA profiles of FLSs and EVs during proliferation. The methods used included nanoparticle tracking analysis, confocal laser scanning microscopy, sandwich-type enzyme-linked sorbent assay, quantitative PCR, and gas chromatography. The expression of hyaluronan synthases 1-3 in FLSs and HA concentrations in conditioned media decreased during cell proliferation. This was associated with elevated proportions of 20:4n-6 and total n-6 polyunsaturated FAs (PUFAs) in high-density cells, reductions in n-3/n-6 PUFA ratios, and up-regulation of cluster of differentiation 44, tumor necrosis factor α, peroxisome proliferator-activated receptor (PPAR)-α, and PPAR-γ. Compared to the parent FLSs, 16:0, 18:0, and 18:1n-9 were enriched in the EV fraction. EV counts decreased during cell growth, and 18:2n-6 in EVs correlated with the cell count. To conclude, FLS proliferation was featured by increased 20:4n-6 proportions and reduced n-3/n-6 PUFA ratios, and FAs with a low degree of unsaturation were selectively transferred from FLSs into EVs. These FA modifications have the potential to affect membrane fluidity, biosynthesis of lipid mediators, and inflammatory processes in joints, and could eventually provide tools for translational studies to counteract cartilage degradation in inflammatory joint diseases.

Small extracellular vesicles (exosomes) and their cargo in pancreatic cancer: Key roles in the hallmarks of cancer

Pancreatic cancer (PC) is a devastating disease, offering poor mortality rates for patients. The current challenge being faced is the inability to diagnose patients in a timely manner, where potentially curative resection provides the best chance of survival. Recently, small/nanosized extracellular vesicles (sEVs), including exosomes, have gained significant preclinical and clinical attention due to their emerging roles in cancer progression and diagnosis. Extracellular vesicles (EVs) possess endogenous properties that offer stability and facilitate crossing of biological barriers for delivery of molecular cargo to cells, acting as a form of intercellular communication to regulate function and phenotype of recipient cells. This review provides an overview of the role of EVs, their subtypes and their oncogenic cargo (as characterised by targeted studies as well as agnostic '-omics' analyses) in the pathobiology of pancreatic cancer. The discussion covers the progress of 'omics technology' that has enabled elucidation of the molecular mechanisms that mediate the role of EVs and their cargo in pancreatic cancer progression.

Biology of the Extracellular Proteasome

Proteasomes are traditionally considered intracellular complexes that play a critical role in maintaining proteostasis by degrading short-lived regulatory proteins and removing damaged proteins. Remarkably, in addition to these well-studied intracellular roles, accumulating data indicate that proteasomes are also present in extracellular body fluids. Not much is known about the origin, biological role, mode(s) of regulation or mechanisms of extracellular transport of these complexes. Nevertheless, emerging evidence indicates that the presence of proteasomes in the extracellular milieu is not a random phenomenon, but rather a regulated, coordinated physiological process. In this review, we provide an overview of the current understanding of extracellular proteasomes. To this end, we examine 143 proteomic datasets, leading us to the realization that 20S proteasome subunits are present in at least 25 different body fluids. Our analysis also indicates that while 19S subunits exist in some of those fluids, the dominant proteasome activator in these compartments is the PA28α/β complex. We also elaborate on the positive correlations that have been identified in plasma and extracellular vesicles, between 20S proteasome and activity levels to disease severity and treatment efficacy, suggesting the involvement of this understudied complex in pathophysiology. In addition, we address the considerations and practical experimental methods that should be taken when investigating extracellular proteasomes. Overall, we hope this review will stimulate new opportunities for investigation and thoughtful discussions on this exciting topic that will contribute to the maturation of the field.

A new strategy to count and sort neutrophil-derived extracellular vesicles: Validation in infectious disorders

Newly recognized polymorphonuclear neutrophil (PMNs) functions include the ability to release subcellular mediators such as neutrophil-derived extracellular vesicles (NDEVs) involved in immune and thrombo-inflammatory responses. Elevation of their plasmatic level has been reported in a variety of infectious and cardiovascular disorders, but the clinical use of this potential biomarker is hampered by methodological issues. Although flow cytometry (FCM) is currently used to detect NDEVs in the plasma of patients, an extensive characterization of NDEVs has never been done. Moreover, their detection remains challenging because of their small size and low antigen density. Therefore, the objective of the present study was first to establish a surface antigenic signature of NDEVs detectable by FCM and therefore to improve their detection in biological fluids by developing a strategy allowing to overcome their low fluorescent signal and reduce the background noise. By testing a large panel of 54 antibody specificities already reported to be positive on PMNs, we identified a profile of 15 membrane protein markers, including 4 (CD157, CD24, CD65 and CD66c) never described on NDEVs. Among them, CD15, CD66b and CD66c were identified as the most sensitive and specific markers to detect NDEVs by FCM. Using this antigenic signature, we developed a new strategy combining the three best antibodies in a cocktail and reducing the background noise by size exclusion chromatography (SEC). This strategy allowed a significant improvement in NDEVs enumeration in plasma from sepsis patients and made it feasible to efficiently sort NDEVs from COVID-19 patients. Altogether, this work opens the door to a more valuable measurement of NDEVs as a potential biomarker in clinical practice. A similar strategy could also be applied to improve detection by FCM of other rare subpopulations of EVs generated by tissues with limited access, such as vascular endothelium, cancer cells or placenta.

Stimulatory Effects of Extracellular Vesicles Derived from Leuconostoc holzapfelii That Exists in Human Scalp on Hair Growth in Human Follicle Dermal Papilla Cells

Human hair follicle dermal papilla cells (HFDPCs) located in hair follicles (HFs) play a pivotal role in hair follicle morphogenesis, hair cycling, and hair growth. Over the past few decades, probiotic bacteria (PB) have been reported to have beneficial effects such as improved skin health, anti-obesity, and immuno-modulation for conditions including atopic dermatitis and inflammatory bowel disease (IBD). PB can secrete 50~150 nm sized extracellular vesicles (EVs) containing microbial DNA, miRNA, proteins, lipids, and cell wall components. These EVs can regulate communication between bacteria or between bacteria and their host. Although numerous biological effects of PB-EVs have been reported, the physiological roles of Leuconostoc holzapfelii (hs-Lh), which is isolated from human scalp tissue, and the extracellular vesicles derived from them (hs-LhEVs) are largely unknown. Herein, we investigated the effects of hs-LhEVs on hair growth in HFDPCs. We show that hs-LhEVs increase cell proliferation, migration, and regulate the cell cycle. Furthermore, hs-LhEVs were found to modulate the mRNA expression of hair-growth-related genes in vitro. These data demonstrate that hs-LhEVs can reduce apoptosis by modulating the cell cycle and promote hair growth by regulation via the Wnt/β-catenin signal transduction pathway.

Dysregulated miR-222-3p in plasma exosomes of preeclampsia patients and its In vitro effect on HTR8/SVneo extravillous trophoblast cells by targeting STMN1

OBJECTIVE

To investigate the diagnostic efficiency of miR-222-3p in plasma exosomes (Exos) and plasma for preeclampsia (PE) and the effect of miR-222-3p targeting STMN1 in PE.

METHODS

MiR-222-3p levels in total plasma and plasma Exos were detected in PE patients and healthy controls. A bioinformatics database and dual-luciferase reporter assay were employed to verify the targeting relationship between miR-222-3p and STMN1. Trophoblast HTR-8/Svneo cells were transfected with miR-222-3p inhibitors with/without STMN1 shRNA, followed by MTT, wound healing and Transwell invasion assays. The mRNA and protein expressions were measured by qRT‒PCR and Western blotting, respectively.

RESULTS

MiR-222-3p levels in total plasma and plasma Exos were higher in PE patients than in healthy controls, particularly in severe PE patients. In addition, miR-222-3p levels in total plasma and plasma Exos from PE patients were positively correlated with diastolic and systolic blood pressure. The area under the curve (AUC) of miR-222-3p in total plasma for PE diagnostic efficiency was 0.798, with a sensitivity of 76.67% and specificity of 71.93%, while the AUC of miR-222-3p in plasma Exos was 0.708 (sensitivity: 61.67%; specificity: 78.95%). In vitro, miR-222-3p targeted STMN1 in HTR-8/Svneo cells. Low miR-222-3p expression reversed the inhibitory effect of STMN1 shRNA on the proliferation, invasion and migration of HTR/SVneo cells.

CONCLUSION

PE patients had increased miR-222-3p expression in total plasma and plasma Exos, which both have high diagnostic efficiency for PE. MiR-222-3p can target STMN1 to promote the proliferation, invasion and migration of HTR-8/Svneo cells and is a potential therapeutic target of PE.

Azurocidin is loaded into small extracellular vesicles via its N-linked glycosylation and promotes intravasation of renal cell carcinoma cells

Azurocidin (AZU1) is an antimicrobial protein secreted by neutrophils that acts as a chemoattractant for monocytes and macrophages and a permeabilizer of vascular endothelial cells. We previously identified AZU1 to be specifically present in extracellular vesicles (EVs) obtained from renal cell carcinoma (RCC) tissues. Here, we examined the relationship between N-linked glycosylation and AZU1 loading into small EVs (SEVs). Inhibition of N-linked glycosylation by introducing mutations in three glycosylation sites inhibited AZU1 loading into SEVs. Furthermore, SEVs released from AZU1-wild-type cells increased the Ca2+ concentration in endothelial cells and the endothelial permeability, whereas SEVs released from AZU1-mutant cells had no significant effect. Anti-AZU1 antibodies diminished the effect of SEVs on endothelial cell sheets. Collectively, we found that N-linked glycosylation of AZU1 directs its loading into SEVs, thereby enabling AZU1-positive SEVs to function as potent permeabilizers of endothelial cells and leading to enhanced transendothelial migration of RCC cells.

Endothelial-Derived Extracellular Vesicles Induce Cerebrovascular Dysfunction in Inflammation

Blood-brain barrier (BBB) dysfunction is a key hallmark in the pathology of many neuroinflammatory disorders. Extracellular vesicles (EVs) are lipid membrane-enclosed carriers of molecular cargo that are involved in cell-to-cell communication. Circulating endothelial EVs are increased in the plasma of patients with neurological disorders, and immune cell-derived EVs are known to modulate cerebrovascular functions. However, little is known about whether brain endothelial cell (BEC)-derived EVs themselves contribute to BBB dysfunction. Human cerebral microvascular cells (hCMEC/D3) were treated with TNFα and IFNy, and the EVs were isolated and characterised. The effect of EVs on BBB transendothelial resistance (TEER) and leukocyte adhesion in hCMEC/D3 cells was measured by electric substrate cell-substrate impedance sensing and the flow-based T-cell adhesion assay. EV-induced molecular changes in recipient hCMEC/D3 cells were analysed by RT-qPCR and Western blotting. A stimulation of naïve hCMEC/D3 cells with small EVs (sEVs) reduced the TEER and increased the shear-resistant T-cell adhesion. The levels of microRNA-155, VCAM1 and ICAM1 were increased in sEV-treated hCMEC/D3 cells. Blocking the expression of VCAM1, but not of ICAM1, prevented sEV-mediated T-cell adhesion to brain endothelia. These results suggest that sEVs derived from inflamed BECs promote cerebrovascular dysfunction. These findings may provide new insights into the mechanisms involving neuroinflammatory disorders.

The Power of Extracellular Vesicles in Myeloproliferative Neoplasms: "Crafting" a Microenvironment That Matters

Myeloproliferative Neoplasms (MPN) are acquired clonal disorders of the hematopoietic stem cells and include Essential Thrombocythemia, Polycythemia Vera and Myelofibrosis. MPN are characterized by mutations in three driver genes (JAK2, CALR and MPL) and by a state of chronic inflammation. Notably, MPN patients experience increased risk of thrombosis, disease progression, second neoplasia and evolution to acute leukemia. Extracellular vesicles (EVs) are a heterogeneous population of microparticles with a role in cell-cell communication. The EV-mediated cross-talk occurs via the trafficking of bioactive molecules such as nucleic acids, proteins, metabolites and lipids. Growing interest is focused on EVs and their potential impact on the regulation of blood cancers. Overall, EVs have been suggested to orchestrate the complex interplay between tumor cells and the microenvironment with a pivotal role in "education" and "crafting" of the microenvironment by regulating angiogenesis, coagulation, immune escape and drug resistance of tumors. This review is focused on the role of EVs in MPN. Specifically, we will provide an overview of recent findings on the involvement of EVs in MPN pathogenesis and discuss opportunities for their potential application as diagnostic and prognostic biomarkers.

CAD increases the long noncoding RNA PUNISHER in small extracellular vesicles and regulates endothelial cell function via vesicular shuttling

Long noncoding RNAs (lncRNAs) have emerged as biomarkers and regulators of cardiovascular disease. However, the expression pattern of circulating extracellular vesicle (EV)-incorporated lncRNAs in patients with coronary artery disease (CAD) is still poorly investigated. A human lncRNA array revealed that certain EV-lncRNAs are significantly dysregulated in CAD patients. Circulating small EVs (sEVs) from patients with (n = 30) or without (n = 30) CAD were used to quantify PUNISHER (also known as AGAP2-antisense RNA 1 [AS1]), GAS5, MALAT1, and H19 RNA levels. PUNISHER (p = 0.002) and GAS5 (p = 0.02) were significantly increased in patients with CAD, compared to non-CAD patients. Fluorescent labeling and quantitative real-time PCR of sEVs demonstrated that functional PUNISHER was transported into the recipient cells. Mechanistically, the RNA-binding protein, heterogeneous nuclear ribonucleoprotein K (hnRNPK), interacts with PUNISHER, regulating its loading into sEVs. Knockdown of PUNISHER abrogated the EV-mediated effects on endothelial cell (EC) migration, proliferation, tube formation, and sprouting. Angiogenesis-related gene profiling showed that the expression of vascular endothelial growth factor A (VEGFA) RNA was significantly increased in EV recipient cells. Protein stability and RNA immunoprecipitation indicated that the PUNISHER-hnRNPK axis regulates the stability and binding of VEGFA mRNA to hnRNPK. Loss of PUNISHER in EVs abolished the EV-mediated promotion of VEGFA gene and protein expression. Intercellular transfer of EV-incorporated PUNISHER promotes a pro-angiogenic phenotype via a VEGFA-dependent mechanism.