Increased Expression of Extracellular Vesicles Is Associated With the Procoagulant State in Patients With Established Rheumatoid Arthritis

Diagnostic and prognostic roles of endothelial- and platelet-derived extracellular vesicles in cardiovascular diseases

Extracellular vesicles (EVs) are membrane-bound structures released by all cell types. They play a critical role in intercellular communication by transferring their cargo, comprising proteins, lipids, metabolites, RNAs, miRNAs, and DNA fragments, to recipient cells. This transfer influences gene expression, signaling pathways, and cellular behavior. Due to their ability to alter the physiology of recipient cells, EVs hold significant therapeutic potential. Additionally, EVs are implicated in various physiological and pathological processes, including immune regulation, cancer progression, and cardiovascular diseases. EVs have been detected in many biological fluids, such as peripheral blood, saliva, urine, cerebrospinal fluid, and breast milk. The cargo of EVs dynamically reflects the physiological and pathological state of their parent cells, making them promising candidates for liquid biopsies in various clinical conditions. Specifically, different EV subtypes in cardiovascular diseases have been studied, with both endothelial and platelet-derived EVs playing significant roles in cardiovascular pathologies. This review focuses on the diagnostic and prognostic potential of endothelial and platelet-derived EVs in cardiovascular diseases, highlighting the role of EV subpopulations.

Newly-diagnosed rheumatoid arthritis patients have elevated levels of plasma extracellular vesicles with protein cargo altered towards inflammatory processes

Extracellular vesicles (EVs) are implicated in rheumatoid arthritis (RA) but have mainly been assessed in RA patients taking disease modifying anti-rheumatic drugs. EVs are nanoparticles important in cell-cell communication and their molecular cargo are biomarker candidates. We characterized the protein profiles of EVs from blood plasma from newly diagnosed, treatment naïve RA patients (N = 32) and compared them to healthy controls (N = 20), by size exclusion chromatography-based EV enrichment coupled with high-resolution quantitative proteomics. The RA patients had higher EV concentration and larger EVs than controls. A total of 682 EV proteins were reliably quantified, and the overall profiles were distinctly different between patients and controls. Specifically, 26 proteins were significantly upregulated and 31 downregulated in RA patients, with several proteins acting in inflammatory networks and with immunologically important upstream regulators. The RA associated EVs appear, based on the tissue expression of their cargo proteins, to originate mainly from hepatocytes or immune cells, like neutrophils. Interestingly, the strongest RA associated EV proteins were inflammatory molecules, like SAA1 and S100A9, already suggested as biomarkers in RA. Furthermore, the RA associated EV proteins were generally not correlated with total serum protein levels, stressing the importance of EV transport of inflammatory proteins in RA pathogenesis.

Extracellular microvesicles from patients with Rheumatoid arthritis promote dendritic cell activation in vitro

Introduction

Rheumatoid Arthritis (RA) is a systemic autoimmune disease characterized by chronic synovial inflammation affecting diarthrodial joints, with cartilage destruction and bone erosion. Environmental inflammatory stimuli can induce maturation of dendritic cells (DCs), which promote differentiation and activation of effector T lymphocytes. We previously highlighted the role of extracellular microvesicles (EMVs) in pathogenesis by carrying antigens that trigger autoantibody production. In this investigation we verified whether EMVs may activate immature monocyte-derived DCs, inducing phenotypic and functional characteristics of mature DCs.

Methods

EMVs were obtained from 7 RA patients naïve to biological disease-modifying anti-rheumatic drugs (DMARDs) and tested for their capability to activate DCs from healthy donors.

Results

We preliminary confirmed by western blot that carbamylated and citrullinated proteins are present in EMVs from RA patients. Moreover, surface marker phenotyping indicated that EMV treated-DCs exhibit increased expression of CD83 and CD86, as well as of CD83+ HLA-DR+ CD80+ CD86+ cells, indicating that the DCs are in a mature state. Furthermore, biochemical data demonstrated that EMVs from plasma of RA patients induce MAPK and NF-κB activation in DCs. EMVs from the plasma of RA patients were also able to stimulate DCs to produce IL-12, IL-1β and IL-10, inducing a proinflammatory phenotype.

Conclusions

These findings demonstrate that EMVs from RA patients promote DC activation in vitro, suggesting a potential mechanism by which RA microenvironment perpetuates inflammation through the modulation of DC function. These knowledges provide new insight in the role of EMVs in the pathogenesis of RA and their potential role as therapeutic targets.

Phosphatidylserine-blocking nanoparticles inhibit thrombosis without increased bleeding in mice

BACKGROUND

Phosphatidylserine (PS) is a procoagulant phospholipid enriched on surfaces of activated vascular cells including platelets, endothelium, monocytes, and microvesicles. As a molecular driver of thrombosis accessible to drug blockade, PS is an attractive pharmacologic target for modulating thrombogenesis, with potentially reduced bleeding risk compared to anticoagulant and antiplatelet therapies.

OBJECTIVES

Test antithrombotic capabilities of a liposomal formulation, Zn-dipicolylamine cyanine-3[22,22]/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (molar ratio, 3:97), designated as DPAL, which we previously described binds selectively to PS-enriched cell surfaces, compared with effects on bleeding, in mouse models.

METHODS

PS-dependent DPAL binding to human and murine platelets was tested in vitro. Thrombosis and bleeding after DPAL intravenous administration were tested in C57Bl/6J mice following FeCl3 carotid arterial injury and tail tip amputation, respectively. Incorporation in hemostatic clots was investigated in the cremaster muscle laser injury model. Toxicity was tested by direct exposure to human endothelial cell cultures.

RESULTS

DPAL bound agonist-stimulated, PS-positive human and murine platelets, blocked by Annexin V or Ano6 deletion, which ablate PS exposure. DPAL prolonged prothrombin time, but did not prevent thrombin-induced fibrinogen receptor activation or aggregation, nor alter blood cell counts including platelets. Following arteriolar laser injury, DPAL bound wound surfaces and edges without destabilizing plugs. DPAL dose-dependently blocked FeCl3-induced arterial thrombosis but did not substantially increase bleeding, or induce endothelial cell death.

CONCLUSION

DPAL reduces thrombogenesis with minimal effects on bleeding in mouse models via selective binding to PS. DPAL may support novel approaches to modulate pathogenic thrombin generation with improved safety profiles in multiple contexts.

Low-Grade Activation of the Extrinsic Coagulation Pathway in Patients with Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC) increases the risk for venous thromboembolism. Tissue factor (TF) initiates the extrinsic coagulation pathway (ECP).

AIMS

To investigate the correlation of UC severity with latent ECP activation and TF expression in primary colonic stromal cells (PCSC).

METHODS

In plasma of 38 UC patients (31 males, disease duration 151 ± 25 months) and 28 healthy controls, exosomes and microparticles (EM) were counted. Moreover, TF protein concentration, activities of EM-bound TF (EM-TFa) and coagulation factor VII (FVIIa) were assessed. In PCSC in culture, TF mRNA (F3) from 12 patients with active UC and 7 controls was evaluated.

RESULTS

UC patients had 4- and 3.7- times more exosomes and microparticles, respectively, than controls. TF protein in UC was correlated with several disease severity indices, such as partial Mayo score (pMs; r 0.443), albumin (- 0.362), ESR (0.353), PLT (0.575), and endoscopic Ms (eMs 0.468). EM-TFa was also significantly higher in UC and was correlated to SIBDQ (- 0.64), albumin (- 0.624), disease extent and eMs (0.422). Refractory-to-treatment patients had significantly higher TF protein, EM-TFa and FVIIa. Even within responders, the need for steroids or biologics correlated with a 2.2-times higher EM-TFa. PCSC from active UC maintained higher F3 than controls, which was correlated to pMs (0.56), albumin (- 0.543) and eMs. Treatment with cytokines further upregulated F3. P for all comparisons was < 0.05.

CONCLUSION

Low-grade activation of the ECP associates with clinical, endoscopic UC activity and response to treatment. TF in PCSC mirrors its systemic activity and points to them as a source.

The role of complement and extracellular vesicles in the development of pulmonary embolism in severe COVID-19 cases

Complement and extracellular vesicles (EVs) association with thrombogenic tendencies is acknowledged, but limited evidence exists for their link to COVID-19 venous thromboembolism. This study aims to examine the relationship between pulmonary embolism and the expression of complement and other proteins related to thrombogenesis in severe Covid-19 patients. We included prospectively 207 severe COVID-19 patients and retrospectively screened for pulmonary embolism (PE). This analysis comprises 20 confirmed PE cases and 20 matched patients without PE. Blood samples taken at the admission in the intensive care unit were analyzed for complement using ELISA. EVs derived from neutrophils, endothelium, or platelets, as well carrying complement or tissue factor were analyzed using flow cytometry. Complement levels were markedly elevated, with a notable increase in C3a and Terminal Complement Complex. The most prevalent EV population was identified as tissue factor (TF)-carrying EVs which peaked in patients with PE during ICU days 4-9. However, for both the complement and analyzed EV populations, no statistically significant differences were found between the patients who developed pulmonary embolism and those who did not. In conclusion, complement factors and EVs expressing tissue factor, along with EVs derived from endothelial cells and platelets, are elevated in severe COVID-19 patients, regardless of the presence of pulmonary embolism. However, the involvement of complement and procoagulant EVs in peripheral plasma in the development of pulmonary embolism is still unclear and requires further investigation.

Updates on the Pathophysiology and Therapeutic Potential of Extracellular Vesicles with Focus on Exosomes in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an incurable autoimmune disease with high morbidity and socioeconomic burden. Advances in therapeutics have improved patients' quality of life, however due to the complex disease pathophysiology and heterogeneity, 30% of patients do not respond to treatment. Understanding how different genetic and environmental factors contribute to disease initiation and development as well as uncovering the interactions of immune components is key to the implementation of effective and safe therapies. Recently, the role of extracellular vesicles (EVs) in RA development and possible treatment has been an area of interest. EVs are small lipid-bound entities, often containing genetic material, proteins, lipids and amino acids, facilitating paracrine intercellular communication. They are secreted by all cells, and it is believed that they possess regulatory functions due to high complexity and functional diversity. Although it has been shown that EVs participate in RA pathophysiology, through immune modulation, their exact role remains elusive. Furthermore, EVs could be a promising therapeutic agent in various diseases including RA, due to their biocompatibility, low toxicity and possible manipulation, but further research is required in this area. This review provides a comprehensive discussion of disease pathophysiology and summarizes the latest knowledge regarding the role and therapeutic potential of EVs in RA.

The Role of Extracellular Vesicles in the Pathogenesis and Treatment of Rheumatoid Arthritis and Osteoarthritis

Cells can communicate with each other through extracellular vesicles (EVs), which are membrane-bound structures that transport proteins, lipids and nucleic acids. These structures have been found to mediate cellular differentiation and proliferation apoptosis, as well as inflammatory responses and senescence, among others. The cargo of these vesicles may include immunomodulatory molecules, which can then contribute to the pathogenesis of various diseases. By contrast, EVs secreted by mesenchymal stem cells (MSCs) have shown important immunosuppressive and regenerative properties. Moreover, EVs can be modified and used as drug carriers to precisely deliver therapeutic agents. In this review, we aim to summarize the current evidence on the roles of EVs in the progression and treatment of rheumatoid arthritis (RA) and osteoarthritis (OA), which are important and prevalent joint diseases with a significant global burden.

Small extracellular vesicles have distinct CD81 and CD9 tetraspanin expression profiles in plasma from rheumatoid arthritis patients

Extracellular vesicles (EVs) are implicated in the pathogenesis of rheumatoid arthritis (RA) but little is known about the composition of specific small EV (sEV) subpopulations. This study aimed to characterize the CD63, CD81 and CD9 tetraspanin profile in the membrane of single EVs in plasma from treatment naïve RA patients and assess potential discrepancies between methotrexate (MTX) responder groups. EVs isolated from plasma were characterized using transmission electron microscopy, and detection of surface markers (CD63, CD81 and CD9) on single EVs was performed on the ExoView platform. All RA patients (N = 8) were newly diagnosed, treatment naïve, females, ACPA positive and former smokers. The controls (N = 5) were matched for age and gender. After three months of MTX treatment, responders (N = 4) were defined as those with ΔDAS28 > 1.2 and DAS28 ≤ 3.2 post-treatment. The isolated EVs were 50-200 nm in size. The RA patients had a higher proportion of both CD9 and CD81 single positive sEVs compared to healthy controls, while there was a decrease in CD81/CD9 double positive sEVs in patients. Stratification of RA patients into MTX responders and non-responders revealed a distinctly higher proportion of CD81 single positive sEVs in the responder group. The proportion of CD81/CD9 double positive sEVs (anti-CD9 captured) was lower in the non-responders, but increased upon 3 months of MTX treatment. Our exploratory study revealed distinct tetraspanin profiles in RA patients suggesting their implication in RA pathophysiology and MTX treatment response.

Platelet-Derived Microparticles and Autoimmune Diseases

Extracellular microparticles provide a means of cell-to-cell communication and can promote information exchanges between adjacent or distant cells. Platelets are cell fragments that are derived from megakaryocytes. Their main functions are to stop bleeding, regulate inflammation, and maintain the integrity of blood vessels. When platelets are activated, they can perform related tasks by secreting platelet-derived microparticles that contain lipids, proteins, nucleic acids, and even organelles. There are differences in the circulating platelet levels in many autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, antiphospholipid antibody syndrome, and Sjogren's syndrome. In this paper, the latest findings in the research field of platelet-derived microparticles are reviewed, including the potential pathogenesis of platelet-derived microparticles in various types of immune diseases, their potential as related markers, and for monitoring the progress and prognosis of disease treatment are expounded.

A Rare Case of Superior Vena Cava Syndrome in a Patient With Rheumatoid Arthritis and IgA Nephropathy

Superior vena cava syndrome (SVCS) is a vascular condition resulting from an impaired venous return to the right atrium. The majority of SVCS cases are caused by mass effect in which extrinsic compression of the vessel leads to obstruction of blood flow. In less common cases of SVCS, thrombus formation and luminal narrowing can result in poor return through the SVC. Inflammatory causes of SVCS are even rarer and poorly documented. IgA nephropathy and rheumatoid arthritis (RA) are two autoimmune diseases with the potential to cause vasculitis, thus increasing the likelihood of intraluminal vessel occlusion. We report a rare case of SVCS in a 65-year-old female with a past medical history significant for atrial fibrillation, IgA nephropathy, chronic kidney disease stage IIIA, and RA who presented with headache, dizziness, and neck pain and swelling extending down the left upper extremity for three days. Inflammatory SVCS is uncommon and cases of SVCS secondary to RA and IgA nephropathy are underreported in the literature thus far. Our hope in presenting this case is to encourage a greater degree of suspicion for vascular complications, such as SVCS, in patients with autoimmune and inflammatory conditions.

The Role of Platelet-Derived Extracellular Vesicles in Immune-Mediated Thrombosis

Platelet-derived extracellular vesicles (PEVs) play important roles in hemostasis and thrombosis. There are three major types of PEVs described based on their size and characteristics, but newer types may continue to emerge owing to the ongoing improvement in the methodologies and terms used to define various types of EVs. As the literature on EVs is growing, there are continuing attempts to standardize protocols for EV isolation and reach consensus in the field. This review provides information on mechanisms of PEV production, characteristics, cellular interaction, and their pathological role, especially in autoimmune and infectious diseases. We also highlight the mechanisms through which PEVs can activate parent cells in a feedback loop.

Particulate Matter Exposure and Allergic Rhinitis: The Role of Plasmatic Extracellular Vesicles and Bacterial Nasal Microbiome

Particulate matter (PM) exposure is linked to the worsening of respiratory conditions, including allergic rhinitis (AR), as it can trigger nasal and systemic inflammation. To unveil the underlying molecular mechanisms, we investigated the effects of PM exposure on the release of plasmatic extracellular vesicles (EV) and on the complex cross-talk between the host and the nasal microbiome. To this aim, we evaluated the effects of PM₁₀ and PM_2.5 exposures on both the bacteria-derived-EV portion (bEV) and the host-derived EVs (hEV), as well as on bacterial nasal microbiome (bNM) features in 26 AR patients and 24 matched healthy subjects (HS). In addition, we assessed the role exerted by the bNM as a modifier of PM effects on the complex EV signaling network in the paradigmatic context of AR. We observed that PM exposure differently affected EV release and bNM composition in HS compared to AR, thus potentially contributing to the molecular mechanisms underlying AR. The obtained results represent the first step towards the understanding of the complex signaling network linking external stimuli, bNM composition, and the immune risponse.