The biology of extracellular vesicles with focus on platelet microparticles and their role in cancer development and progression

Review of exosomes and their potential for veterinary medicine

Small extracellular vesicles called exosomes are released by almost all cell types and play a crucial role in both healthy and pathological circumstances. Exosomes, found in biological fluids (including plasma, urine, milk, semen, saliva, abdominal fluid and cervical vaginal fluid) and ranging in size from 50 to 150 nm, are critical for intercellular communication. Analysis of exosomal cargos, including micro RNAs (miRNAs), proteins and lipids, has been proposed as valuable diagnostic and prognostic biomarkers of disease. Exosomes can also be used as novel, cell-free, treatment strategies. In this review, we discuss the role, significance and application of exosomes and their cargos in diseases of animals.

Extracellular vesicles as tools and targets in therapy for diseases

Extracellular vesicles (EVs) are nano-sized, membranous structures secreted into the extracellular space. They exhibit diverse sizes, contents, and surface markers and are ubiquitously released from cells under normal and pathological conditions. Human serum is a rich source of these EVs, though their isolation from serum proteins and non-EV lipid particles poses challenges. These vesicles transport various cellular components such as proteins, mRNAs, miRNAs, DNA, and lipids across distances, influencing numerous physiological and pathological events, including those within the tumor microenvironment (TME). Their pivotal roles in cellular communication make EVs promising candidates for therapeutic agents, drug delivery systems, and disease biomarkers. Especially in cancer diagnostics, EV detection can pave the way for early identification and offers potential as diagnostic biomarkers. Moreover, various EV subtypes are emerging as targeted drug delivery tools, highlighting their potential clinical significance. The need for non-invasive biomarkers to monitor biological processes for diagnostic and therapeutic purposes remains unfulfilled. Tapping into the unique composition of EVs could unlock advanced diagnostic and therapeutic avenues in the future. In this review, we discuss in detail the roles of EVs across various conditions, including cancers (encompassing head and neck, lung, gastric, breast, and hepatocellular carcinoma), neurodegenerative disorders, diabetes, viral infections, autoimmune and renal diseases, emphasizing the potential advancements in molecular diagnostics and drug delivery.

Revealing profile of cancer-educated platelets and their factors to foster immunotherapy development

Among multiple hemostasis components, platelets hyperactivity plays major roles in cancer progression by providing surface and internal components for intercellular crosstalk as well as by behaving like immune cells. Since platelets participate and regulate immunity in homeostatic and disease states, we assumed that revealing platelets profile might help in conceiving novel anti-cancer immune-based strategies. The goal of this review is to compile and discuss the most recent reports on the nature of cancer-associated platelets and their interference with immunotherapy. An increasing number of studies have emphasized active communication between cancer cells and platelets, with platelets promoting cancer cell survival, growth, and metastasis. The anti-cancer potential of platelet-directed therapy has been intensively investigated, and anti-platelet agents may prevent cancer progression and improve the survival of cancer patients. Platelets can (i) reduce antitumor activity; (ii) support immunoregulatory cells and factors generation; (iii) underpin metastasis and, (iv) interfere with immunotherapy by expressing ligands of immune checkpoint receptors. Mediators produced by tumor cell-induced platelet activation support vein thrombosis, constrain anti-tumor T- and natural killer cell response, while contributing to extravasation of tumor cells, metastatic potential, and neovascularization within the tumor. Recent studies showed that attenuation of immunothrombosis, modulation of platelets and their factors have a good perspective in immunotherapy optimization. Particularly, blockade of intra-tumoral platelet-associated programmed death-ligand 1 might promote anti-tumor T cell-induced cytotoxicity. Collectively, these findings suggest that platelets might represent the source of relevant cancer staging biomarkers, as well as promising targets and carriers in immunotherapeutic approaches for combating cancer.

Extracellular microvesicles: biologic properties, biogenesis, and applications in leukemia

Microvesicles are cellular membrane vesicles of which size is limited to 30-1000 nm. Almost all cells release them in response to activation signals and apoptosis. Their ability for intercellular communication and enhancement of potential for information exchange (between them) has attracted much interest. Their content is affected by the content of the mother cell, which can help identify their origin. Furthermore, these particles can change the physiology of the target cells by transferring a set of molecules to them and changing the epigenetics of the cells by transferring DNA and RNA. These changes can be induced in cells close to the mother and distant cells. Significant activities of these microvesicles are known both in physiological and pathologic conditions. In this regard, we have reviewed these small particle elements, their contents, and the way of synthesis. Finally, we discussed their current known roles to reveal more potential applications in leukemia.

Ultrasound-Targeted Microbubble Destruction Assisted Delivery of Platelet-Rich Plasma-Derived Exosomes Promoting Peripheral Nerve Regeneration

Peripheral nerve injury is prevalent and has a high disability rate in clinical settings. Current therapeutic methods have not achieved satisfactory efficacy, underscoring the need for novel approaches to nerve restoration that remains an active area of research in neuroscience and regenerative medicine. In this study, we isolated platelet-rich plasma-derived exosomes (PRP-exos) and found that they can significantly enhance the proliferation, migration, and secretion of trophic factors by Schwann cells (SCs). In addition, there were marked changes in transcriptional and expression profiles of SCs, particularly via the upregulation of genes related to biological functions involved in nerve regeneration and repair. In the rat model of sciatic nerve crush injury, ultrasound-targeted microbubble destruction (UTMD) enhanced the efficiency of PRP-exos delivery to the injury site. This approach ensured a high concentration of PRP-exos in the injured nerve and improved the therapeutic outcomes. In conclusion, PRP-exos may promote nerve regeneration and repair, and UTMD may increase the effectiveness of targeted PRP-exos delivery to the injured nerve and enhance the therapeutic effect.

The prospects of microphysiological systems in modeling platelet pathophysiology in cancer

The contribution of platelets is well recognized in thrombosis and hemostasis. However, platelets also promote tumor progression and metastasis through their crosstalk with various cells of the tumor microenvironment (TME). For example, several cancer models continue to show that platelet functions are readily altered by cancer cells upon activation leading to the formation of platelet-tumor aggregates, triggering release of soluble factors from platelet granules and altering platelet turnover. Further, activated platelets protect tumor cells from shear forces in circulation and assault of cytotoxic natural killer (NK) cells. Platelet-secreted factors promote proliferation of malignant cells, metastasis, and chemoresistance. Much of our knowledge of platelet biology in cancer has been achieved with animal models, particularly murine. However, this preclinical understanding of the complex pathophysiology is yet to be fully realized and translated to clinical trials in terms of new approaches to treat cancer via controlling the platelet function. In this review, we summarize the current state of knowledge of platelet physiology obtained through existing in vivo and in vitro cancer models, the complex interactions of platelets with cancer cells in TME and the pathways by which platelets may confer chemoresistance. Since the FDA Modernization Act recently passed by the US government has made animal models optional in drug approvals, we critically examine the existing and futuristic value of employing bioengineered microphysiological systems and organ-chips to understand the mechanistic role of platelets in cancer metastasis and exploring novel therapeutic targets for cancer prevention and treatment.

Cryopreservation affects platelet macromolecular composition over time after thawing and differently impacts on cancer cells behavior in vitro

Cryopreservation affects platelets' function, questioning their use for cancer patients. We aimed to investigate the biochemical events that occur over time after thawing to optimize transfusion timing and evaluate the effect of platelet supernatants on tumor cell behavior in vitro. We compared fresh (Fresh-PLT) with Cryopreserved platelets (Cryo-PLT) at 1 h, 3 h and 6 h after thawing. MCF-7 and HL-60 cells were cultured with Fresh- or 1 h Cryo-PLT supernatants to investigate cell proliferation, migration, and PLT-cell adhesion. We noticed a significant impairment of hemostatic activity accompanied by a post-thaw decrease of CD42b+ , which identifies the CD62P--population. FTIR spectroscopy revealed a decrease in the total protein content together with changes in their conformational structure, which identified two sub-groups: 1) Fresh and 1 h Cryo-PLT; 2) 3 h and 6 h cryo-PLT. Extracellular vesicle shedding and phosphatidylserine externalization (PS) increased after thawing. Cryo-PLT supernatants inhibited cell proliferation, impaired MCF-7 cell migration, and reduced ability to adhere to tumor cells. Within the first 3 hours after thawing, irreversible alterations of biomolecular structure occur in Cryo-PLT. Nevertheless, Cryo-PLT should be considered safe for the transfusion of cancer patients because of their insufficient capability to promote cancer cell proliferation, adhesion, or migration.

Platelet-derived microvesicles induce intracellular calcium mobilization in human platelets

Platelet-derived microvesicles (PMVs) represent a significant proportion of microvesicles in circulation and have been linked to various pathophysiological complications. Recent research suggests that PMVs carry significant amounts of cargo that can affect cellular functions by influencing calcium oscillations in target cells. As calcium is involved in multiple cellular processes, including hemostasis and thrombosis, this study aimed to investigate the impact of PMVs on platelet calcium mobilization. The study found that PMVs increase platelet intracellular calcium levels via both intracellular storage and extracellular space in a dose-dependent manner. The study highlighted the critical role of the dense tubular system, acidic vacuoles, mitochondrial stores, and store-operated calcium entry (SOCE) in PMV-mediated calcium release in human platelets. Moreover, the study revealed that PMV-induced calcium rise in platelets does not occur via sarcoendoplasmic reticulum calcium ATPase, and extracellular calcium addition further increases the calcium level in platelets, demonstrating the involvement of SOCE. These findings provide insights into the platelet stimulation signaling mechanisms and contributes to our understanding of platelet and cell behavior when exposed to PMV-rich environments.

The value of platelet-rich plasma-derived extracellular vesicles in modern medicine

Platelet-rich plasma (PRP) has been widely used in clinical practice. The mechanism by which PRP promotes tissue repair lies in the release of multiple growth factors upon platelet activation, which accelerates the proliferation and differentiation of repair cells and the synthesis of extracellular matrix. In recent years, as extracellular vesicles (EVs) research has increased and intensified, it has been found that EVs also play an important role in tissue repair. This article provides a comprehensive review of the role of PRP and PRP-derived extracellular vesicles (PRP-EVs) in tissue repair. It discusses the biological characteristics, extraction, identification, activation, and preservation of PRP-EVs. It also reviews their applications in orthopedics and wound repair. The article highlights the importance of PRP-EVs in modern medicine and suggests that they could be a promising natural nanocarrier.

Platelet-Based Nanoparticles with Stimuli-Responsive for Anti-Tumor Therapy

In addition to hemostasis and coagulation, years of studies have proved that platelets are involved in the whole process of tumor progression, including tumor invasion, intravasation, extravasation, and so on. It means that this property of platelets can be used in anti-tumor therapy. However, traditional platelet-based antitumor drugs often cause autologous platelet damage due to lack of targeting, resulting in serious side effects. Therefore, the researchers designed a variety of anti-tumor drug delivery systems based on platelets by targeting platelets or platelet membrane coating. The drug delivery systems have special response modes, which is crucial in the design of nanoparticles. These modes enhance the targeting and improve the anti-tumor effect. Here, we present a review of recent discoveries in the field of the crosstalk between platelets and tumors and the progress of platelet-based anti-tumor nanoparticles.

Plant and mammalian-derived extracellular vesicles: a new therapeutic approach for the future

Background: In recent years, extracellular vesicles have been recognized as important mediators of intercellular communication through the transfer of active biomolecules (proteins, lipids, and nucleic acids) across the plant and animal kingdoms and have considerable roles in several physiological and pathological mechanisms, showing great promise as new therapeutic strategies for a variety of pathologies. Methods: In this study, we carefully reviewed the numerous articles published over the last few decades on the general knowledge of extracellular vesicles, their application in the therapy of various pathologies, and their prospects as an approach for the future. Results: The recent discovery and characterization of extracellular vesicles (EVs) of diverse origins and biogenesis have altered the current paradigm of intercellular communication, opening up new diagnostic and therapeutic perspectives. Research into these EVs released by plant and mammalian cells has revealed their involvement in a number of physiological and pathological mechanisms, such as embryonic development, immune response, tissue regeneration, and cancer. They are also being studied as potential biomarkers for disease diagnosis and vectors for drug delivery. Conclusion: Nanovesicles represent powerful tools for intercellular communication and the transfer of bioactive molecules. Their molecular composition and functions can vary according to their origin (plant and mammalian), so their formation, composition, and biological roles open the way to therapeutic applications in a variety of pathologies, which is arousing growing interest in the scientific community. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT03608631.

Platelet-derived extracellular vesicles for drug delivery

Platelet-derived extracellular vesicles (PEVs) are a subset of EVs that are released from platelets, which are small nuclear cell fragments that play a critical role in hemostasis and thrombosis. PEVs have been shown to have important roles in a variety of physiological and pathological processes, including inflammation, angiogenesis, and cancer. Recently, researchers, including our group have utilized PEVs as drug delivery platforms as PEVs could target inflammatory sites both passively and actively. This review summarizes the biological function of PEVs, introduces recent applications of PEVs in targeted drug delivery, and provides an outlook for the further development of utilizing PEVs for drug delivery.

Engineered Extracellular Vesicles for Drug Delivery in Therapy of Stroke

Extracellular vesicles (EVs) are promising therapeutic modalities for treating neurological conditions. EVs facilitate intercellular communication among brain cells under normal and abnormal physiological conditions. The potential capability of EVs to pass through the blood-brain barrier (BBB) makes them highly promising as nanocarrier contenders for managing stroke. EVs possess several potential advantages compared to existing drug-delivery vehicles. These advantages include their capacity to surpass natural barriers, target specific cells, and stability within the circulatory system. This review explores the trafficking and cellular uptake of EVs and evaluates recent findings in the field of EVs research. Additionally, an overview is provided of the techniques researchers utilize to bioengineer EVs for stroke therapy, new results on EV-BBB interactions, and the limitations and prospects of clinically using EVs for brain therapies. The primary objective of this study is to provide a comprehensive analysis of the advantages and challenges related to engineered EVs drug delivery, specifically focusing on their application in the treatment of stroke.

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.

Enhanced in vivo and ex vivo thrombin generation after lower-leg trauma, but not after knee arthroscopy

BACKGROUND

There is room for improvement of prevention of venous thromboembolism (VTE) after lower-leg cast application or knee arthroscopy. Information about the mechanism of clot formation in these patients may be useful to identify new prophylaxis targets. We aimed to study the effect of 1) lower-leg injury and 2) knee arthroscopy on thrombin generation.

METHODS

A cross-sectional study was conducted using plasma samples of POT-(K)CAST trials to measure ex vivo thrombin generation (Calibrated Automated Thrombography [CAT]) and plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin (TAT), fibrinopeptide A (FPA). Plasma was obtained shortly after lower-leg trauma or before and after (< 4 h) knee arthroscopy. Participants were randomly selected from those who did not develop VTE. For aim 1, samples of 88 patients with lower-leg injury were compared with 89 control samples (i.e., preoperative samples of arthroscopy patients). Linear regression was used to obtain mean differences (or ratios if ln-retransformed because of skewedness) adjusted for age, sex, body mass index, comorbidities. For aim 2, pre- and postoperative samples of 85 arthroscopy patients were compared, for which mean changes were obtained.

RESULTS

In patients with lower-leg injury (aim 1), endogenous thrombin potential, thrombin peak, velocity index, FPA and TAT were increased as compared with controls. In arthroscopy patients (aim 2), pre- and postoperative levels were similar for all parameters.

CONCLUSION

Lower-leg trauma increases thrombin generation both ex vivo and in vivo, in contrast to knee arthroscopy. This may imply that the pathogenesis of VTE is different in both situations.

Circulating Extracellular Vesicles Are Increased in Newly Diagnosed Celiac Disease Patients

Extracellular vesicles (EVs) are a class of circulating entities that are involved in intercellular crosstalk mechanisms, participating in homeostasis maintenance, and diseases. Celiac disease is a gluten-triggered immune-mediated disorder, characterized by the inflammatory insult of the enteric mucosa following local lymphocytic infiltration, resulting in villous atrophy. The goal of this research was the assessment and characterization of circulating EVs in celiac disease patients, as well as in patients already on an adequate gluten-free regimen (GFD). For this purpose, a novel and validated technique based on polychromatic flow cytometry that allowed the identification and enumeration of different EV sub-phenotypes was applied. The analysis evidenced that the total, annexin V+, leukocyte (CD45+), and platelet (CD41a+) EV counts were significantly higher in both newly diagnosed celiac disease patients and patients under GFD compared with the healthy controls. Endothelial-derived (CD31+) and epithelial-derived (EpCAM+) EV counts were significantly lower in subjects under gluten exclusion than in celiac disease patients, although EpCAM+ EVs maintained higher counts than healthy subjects. The numbers of EpCAM+ EVs were a statistically significant predictor of intraepithelial leukocytes (IEL). These data demonstrate that EVs could represent novel and potentially powerful disease-specific biomarkers in the context of celiac disease.

Research landscape of exosomes in platelets from 2000 to 2022: A bibliometric analysis

Background

Blood-derived exosomes are involved in developing multiple pathological processes, with platelets being the most well-known source. Related studies have become an area of research with significant value and potential. However, no bibliometric studies in this field have yet been identified. We aimed to analyze the hotspots and academic trends of platelet exosome research through bibliometric visualization to actively grasp the research base in this field and track its developmental orientation.

Methods

From 2000 to 2022, we screened all relevant publications on platelet exosome-related research from the Web of Science database, generated knowledge maps using VOSviewer and CiteSpace software, and analyzed research trends in the field.

Results

A total of 722 articles were screened for inclusion based on the search strategy. The number of articles on exosome studies in platelets has expanded vastly. The USA and the People's Republic of China contributed substantially among 69 countries or regions. Amsterdam University and Semmelweis University are the research institutions with the most publications. The most studied and co-cited journals were the International Journal of Molecular Sciences and the Journal of Extracellular Vesicles. We identified 4,598 authors, with Nieuwland Rienk having the highest number of articles and Bruno Stefania having the most cited publications. Keywords of great interest include "thrombosis," "anti-inflammatory," "anti-apoptosis," "angiogenesis," "microparticles," "miRNAs," "stem cells," and "biomarkers," which are key research areas for future development.

Conclusion

We used bibliometric and visualization methods to identify hotspots and trends in platelet exosome research. Platelet exosome research is widely expanding. Future research will most likely focus on "thrombosis," "anti-inflammatory," "anti-apoptosis," "angiogenesis," "microparticles," "miRNAs," "stem cells," and "biomarkers."

Natural cell based biomimetic cellular transformers for targeted therapy of digestive system cancer

Digestive system cancer is the most common cause of cancer death in the world. Although cancer treatment options are increasingly diversified, the mortality rate of malignant cancer of the digestive system remains high. Therefore, it is necessary to explore effective cancer treatment methods. Recently, biomimetic nanoparticle delivery systems based on natural cells that organically integrate the low immunogenicity, high biocompatibility, cancer targeting, and controllable, versatile functionality of smart nanocarrier design with natural cells have been expected to break through the bottleneck of tumor targeted therapy. In this review, we focus on the dynamic changes and complex cellular communications that occur in vivo in natural cells based vehicles. Recent studies on the development of advanced targeted drug delivery systems using the dynamic behaviors such as specific surface protein affinity, morphological changes, and phenotypic polarization of natural cells are summarized. In addition to drug delivery mediated by dynamic behavior, functional “delivery” based on the natural cell themselves is also involved. Aiming to make the best use of the functions of cells, providing clues for the development of advanced drug delivery platforms.

Platelet detection as a new liquid biopsy tool for human cancers

Cancer is still a leading cause of death worldwide and liquid biopsy is a powerful tool that can be applied to different stages of cancer screening and treatment. However, as the second most abundant cell type in the bloodstream, platelets are isolated through well-established and fast methods in clinic but their value as a BioSource of cancer biomarkers is relatively recent. Many studies demonstrated the bidirectional interaction between cancer cells and platelets. Platelets transfer various proteins (e.g., growth factors, cytokine, chemokines) and RNAs (e.g., mRNA, lncRNA, miRNA, circRNA) into the tumor cells and microenvironment, leading the stimulation of tumor growth and metastasis. In turn, the platelet clinical characteristics (e.g., count and volume) and contents (e.g., RNA and protein) are altered by the interactions with cancer cells and this enables the early cancer detection using these features of platelets. In addition, platelet-derived microparticles also demonstrate the prediction power of being cancer biomarkers. In this review, we focus on the clinical applications of platelet detection using the platelet count, mean platelet volume, platelet RNA and protein profiles for human cancers and discuss the gap in bringing these implementations into the clinic.

Canine B Cell Lymphoma- and Leukemia-Derived Extracellular Vesicles Moderate Differentiation and Cytokine Production of T and B Cells In Vitro

Extracellular vesicles (EVs) are formed in physiological and pathological conditions by almost all mammalian cells. They are known as submicron “molecules” that transport and horizontally transfer their cargo from maternal cells to donor cells. Moreover, cancer cells produce tumor-derived EVs (TEVs), which are present in blood of patients with solid tumors and those with hematological malignancies. Their role in evading immune system surveillance and induction of immunosuppression in hematological cancer is limited. According to the authors’ best knowledge, there is no information about the impact of TEVs from canine lymphoma (CLBL-1) and leukemia (CLB70) on lymphocytes isolated from peripheral blood mononuclear cells (PBMCs). In conclusion, we demonstrate in in vitro experiments that CLBL-1 EVs and CLB70 EVs are effectively taken up by T and B lymphocytes. TEVs decrease the percentage of B lymphocytes and increase that of T lymphocytes, and change T cells’ phenotype into the effector memory (EM) or terminally differentiated effector memory (TEMRA) subtype after in vitro co-culturing. Moreover, CLBL70 EVs have pro-tumorogenic properties by inhibiting the production of CD8+IL-17+ cells.

Tumour Derived Extracellular Vesicles: Challenging Target to Blunt Tumour Immune Evasion

Simple Summary

Tumour onset and development occur because of specific immune support. The immune system, which is originally able to perceive and eliminate incipient cancer cells, becomes suppressed and hijacked by cancer. For these purposes, tumour cells use extracellular vesicles (TEVs). Specific molecular composition allows TEVs to reprogram immune cells towards tumour tolerance. Circulating TEVs move from their site of origin to other organs, preparing “a fertile soil” for metastasis formation. This implies that TEV molecular content can provide a valuable tool for cancer biomarker discovery and potential targets to reshape the immune system into tumour recognition and eradication.

Abstract

Control of the immune response is crucial for tumour onset and progression. Tumour cells handle the immune reaction by means of secreted factors and extracellular vesicles (EV). Tumour-derived extracellular vesicles (TEV) play key roles in immune reprogramming by delivering their cargo to different immune cells. Tumour-surrounding tissues also contribute to tumour immune editing and evasion, tumour progression, and drug resistance via locally released TEV. Moreover, the increase in circulating TEV has suggested their underpinning role in tumour dissemination. This review brings together data referring to TEV-driven immune regulation and antitumour immune suppression. Attention was also dedicated to TEV-mediated drug resistance.

Circulating microparticles as indicators of cardiometabolic risk in PCOS

Polycystic ovary syndrome (PCOS), the most prevalent endocrine disturbance of the female reproductive system, is associated with several pathologic conditions, such as metabolic syndrome, obesity, diabetes, dyslipidemia, and insulin resistance, all of which are tightly connected to its progression. These factors are associated with a type of extracellular vesicle, ie, microparticles (MPs), released by shedding due to cell activation and apoptosis. Circulating MPs (cMPs) are secreted by a variety of cells, such as platelets, endothelial, leukocytes, and erythrocytes, and contain cytoplasmic substances derived from parent cells that account for their biologic activity. Current evidence has clearly shown that increased cMPs contribute to endothelial dysfunction, diabetes, hypertriglyceridemia, metabolic syndrome, cardiovascular abnormalities as well as PCOS. It has also been reported that platelet and endothelial MPs are specifically increased in PCOS thus endangering vascular health and subsequent cardiovascular disease. Given the importance of cMPs in the pathophysiology of PCOS, we review the role of cMPs in PCOS with a special focus on cardiometabolic significance.

Platelet Extracellular Vesicles Are Taken up by Canine T Lymphocytes but Do Not Play a Role in Their Proliferation, Differentiation and Cytokine Production In Vitro

Eukaryotic and prokaryotic cells in physiological and pathological conditions form membrane-bound extracellular vesicles, known as EVs. The ability of these submicron structures to transfer their cargoes (miRNA, DNA, protein, cytokines, receptors, etc.) into recipient cells is described. Recent data revealed that platelet-derived extracellular vesicles (PEVs) crosstalk promotes cancer growth and metastasis formation. Moreover, they exert immunosuppressive activities on phagocytes. This EV subpopulation is the most abundant amongst all types in circulation. According to the authors' best knowledge, there is no information regarding the impact of PEVs on canine lymphocytes. The aim of this study was to evaluate the influence of PEVs on lymphocyte proliferation, phenotype and cytokine production in vitro. In the study, it was demonstrated (i) that PEVs interact differently with lymphocyte subsets and are preferentially associated with T-lymphocytes PBMC, while (ii) they are rarely detected in association with B-lymphocytes, and there is evidence that (iii) PEV uptake is observed after 7 h of co-culturing with lymphocytes. In addition, obtained data support the notion that PEVs do not influence in vitro lymphocyte proliferation, differentiation and cytokine production in a canine model.

Microparticles in Diabetic Kidney Disease

Diabetickidneydisease(DKD)isthemostcommoncauseofrenal failure and a major contributor to the socioeconomic burden in chronic kidney disease (CKD) patients worldwide. The pathogenesis of DKD involves all the structures in the nephron, and it is indicated by proteinuria, hypertension, and progressive decline in renal function, leading tosubstantialmorbidityandmortality. Due to the limitations of currently available standard markers (albuminuria and glomerular filtration rate) in the diagnosis and clinical grading of DKD, it's time to have novel biomarkers for early detection, targeted and effective therapy to prevent the progression. Microparticles (MPs) are extracellular vesicles measuring 0.1 to 1 micron derived by cytoskeletal reorganization in the form of cytoplasmic blebs which alters the phospholipid cytochemistry of the cell membrane. They are shed during cell activation and apoptosis as well as plays an important role in cell-to-cell communication. Over the last few decades, both plasma and urinary MPs have been investigated, validated and the preliminary research looks promising. With alterations in their number and composition documented in clinical situations involving both Type1 and 2 diabetes mellitus, microparticles assay appears to be promising in early diagnosis and prognostication of DKD. WecoverthebasicsofmicroparticlesandtheirinvolvementinDKDinthisreviewarticle.

Engineered Small Extracellular Vesicles as a FGL1/PD-L1 Dual-Targeting Delivery System for Alleviating Immune Rejection

There is an urgent need for developing new immunosuppressive agents due to the toxicity of long-term use of broad immunosuppressive agents after organ transplantation. Comprehensive sample analysis revealed dysregulation of FGL1/LAG-3 and PD-L1/PD-1 immune checkpoints in allogeneic heart transplantation mice and clinical kidney transplant patients. In order to enhance these two immunosuppressive signal axes, a bioengineering strategy is developed to simultaneously display FGL1/PD-L1 (FP) on the surface of small extracellular vesicles (sEVs). Among various cell sources, FP sEVs derived from mesenchymal stem cells (MSCs) not only enriches FGL1/PD-L1 expression but also maintain the immunomodulatory properties of unmodified MSC sEVs. Next, it is confirmed that FGL1 and PD-L1 on sEVs are specifically bound to their receptors, LAG-3 and PD-1 on target cells. Importantly, FP sEVs significantly inhibite T cell activation and proliferation in vitro and a heart allograft model. Furthermore, FP sEVs encapsulated with low-dose FK506 (FP sEVs@FK506) exert stronger effects on inhibiting T cell proliferation, reducing CD8+ T cell density and cytokine production in the spleens and heart grafts, inducing regulatory T cells in lymph nodes, and extending graft survival. Taken together, dual-targeting sEVs have the potential to boost the immune inhibitory signalings in synergy and slow down transplant rejection.

Proteomic analysis of human umbilical cord serum exosomes using mass spectrometry and preliminary study of their biological activities in liver cancer cell lines

Exosomes are membranous extracellular vesicles 50-100 nm in size, which are involved in cellular communication via the delivery of proteins, lipids and RNA. Emerging evidence shows that exosomes play a critical role in cancer. It has recently been revealed that maternal and umbilical cord serum (UCS)-derived exosomes may enhance endothelial cell proliferation and migration. However, the role of exosomes isolated from the human umbilical cord in cancer development has not been investigated. To explore the potential differences in the composition and function of proteins from umbilical serum exosomes (UEs) and maternal serum exosomes, a proteomic analysis of exosomes was conducted using mass spectrometry and bioinformatics. Moreover, Cell Counting Kit-8 assays and flow cytometry were used to study the biological effects of UEs on liver cancer cell lines. The present study demonstrated that UCS was enriched with proteins involved in extracellular matrix-receptor interactions, which may be closely related to cell metastasis and proliferation. The findings further indicated that exosomes derived from human umbilical serum could inhibit the viability and induce apoptosis of liver cancer cells. This suggests that UCS-derived exosomes may represent potential leads for the development of biotherapy for liver cancer.

A panel of platelet-associated circulating long non-coding RNAs as potential biomarkers for colorectal cancer

Evidence has suggested the potential of tumor-educated platelets as a biomarker trove for cancer diagnostics, but the difficulty in isolation limits its application. Since most of the circulating RNAs are derived from platelets, the change of RNA profile in platelets may lead to altered RNA expression in serum. Here, we identified a panel of platelet-associated long non-coding RNAs (lncRNAs) and evaluated its diagnostic capacity in serum of colorectal cancer (CRC) patients. Four lncRNAs, LNCAROD, SNHG20, LINC00534, and TSPOAP-AS1, were upregulated in both platelets and serum of CRC patients. A binary logistic model derived from them has validated area under roc curve of 0.78 indicating great performance. Furthermore, the expression levels of LNCAROD and TSPOAP-AS1 were correlated with cancer staging and tumor location. Together, our results add novel lncRNA biomarkers to the list of blood tests for CRC diagnostics and provide molecular evidence for the cross-talk between CRC platelets and serum.

COVID-19 Infection and Circulating Microparticles-Reviewing Evidence as Microthrombogenic Risk Factor for Cerebral Small Vessel Disease

Severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) due to novel coronavirus disease 2019 (COVID-19) has affected the global society in numerous unprecedented ways, with considerable morbidity and mortality. Both direct and indirect consequences from COVID-19 infection are recognized to give rise to cardio- and cerebrovascular complications. Despite current limited knowledge on COVID-19 pathogenesis, inflammation, endothelial dysfunction, and coagulopathy appear to play critical roles in COVID-19-associated cerebrovascular disease (CVD). One of the major subtypes of CVD is cerebral small vessel disease (CSVD) which represents a spectrum of pathological processes of various etiologies affecting the brain microcirculation that can trigger subsequent neuroinflammation and neurodegeneration. Prevalent with aging, CSVD is a recognized risk factor for stroke, vascular dementia, and Alzheimer's disease. In the background of COVID-19 infection, the heightened cellular activations from inflammations and oxidative stress may result in elevated levels of microthrombogenic extracellular-derived circulating microparticles (MPs). Consequently, MPs could act as pro-coagulant risk factor that may serve as microthrombi for the vulnerable microcirculation in the brain leading to CSVD manifestations. This review aims to appraise the accumulating body of evidence on the plausible impact of COVID-19 infection on the formation of microthrombogenic MPs that could lead to microthrombosis in CSVD manifestations, including occult CSVD which may last well beyond the pandemic era.

SARS-CoV-2 Initiates Programmed Cell Death in Platelets

Supplemental Digital Content is available in the text.

Coronavirus disease 2019 (COVID-19) is characterized by increased incidence of microthrombosis with hyperactive platelets sporadically containing viral RNA. It is unclear if SARS-CoV-2 (severe acute respiratory syndrome, corona virus-2) directly alters platelet activation or if these changes are a reaction to infection-mediated global inflammatory alterations. Importantly, the direct effect of SARS-CoV-2 on platelets has yet to be studied.

Liquid Biopsy, the hype vs. hope in molecular and clinical oncology

The molecular landscape of tumors has been traditionally established using a biopsy or resection specimens. These modalities result in sampling bias that offer only a single snapshot of tumor heterogeneity. Over the last decade intensive research towards alleviating such a bias and obtaining an integral yet accurate portrait of the tumors, evolved to the use of established molecular and genetic analysis using blood and several other body fluids, such as urine, saliva, and pleural effusions as liquid biopsies. Genomic profiling of the circulating markers including circulating cell-free tumor DNA (ctDNA), circulating tumor cells (CTCs) or even RNA, proteins, and lipids constituting exosomes, have facilitated the diligent monitoring of response to treatment, allowed one to follow the emergence of drug resistance, and enumerate minimal residual disease. The prevalence of tumor educated platelets (TEPs) and our understanding of how tumor cells influence platelets are beginning to unearth TEPs as a potentially dynamic component of liquid biopsies. Here, we review the biology, methodology, approaches, and clinical applications of biomarkers used to assess liquid biopsies. The current review addresses recent technological advances and different forms of liquid biopsy along with upcoming challenges and how they can be integrated to get the best possible tumor-derived genetic information that can be leveraged to more precise therapies for patient as liquid biopsies become increasingly routine in clinical practice.

Platelet-Cancer Interplay: Molecular Mechanisms and New Therapeutic Avenues

Although platelets are critically involved in thrombosis and hemostasis, experimental and clinical evidence indicate that platelets promote tumor progression and metastasis through a wide range of physical and functional interactions between platelets and cancer cells. Thrombotic and thromboembolic events are frequent complications in patients with solid tumors. Hence, cancer modulates platelet function by directly inducing platelet-tumor aggregates and triggering platelet granule release and altering platelet turnover. Also, platelets enhance tumor cell dissemination by activating endothelial cell function and recruiting immune cells to primary and metastatic tumor sites. In this review, we summarize current knowledge on the complex interactions between platelets and tumor cells and the host microenvironment. We also critically discuss the potential of anti-platelet agents for cancer prevention and treatment.

Horizontal MicroRNA Transfer by Platelets - Evidence and Implications

For decades, platelets have been known for their central role in hemostasis and their ability to release bioactive molecules, allowing inter-platelet communication and crosstalk with the immune system and vascular cells. However, with the detection of microRNAs in platelets and platelet-derived microvesicles (MVs), a new level of inter-cellular regulation was revealed. By shedding MVs from their plasma membrane, platelets are able to release functional microRNA complexes that are protected from plasma RNases. Upon contact with macrophages, endothelial cells and smooth muscle cells platelet microRNAs are rapidly internalized and fine-tune the functionality of the recipient cell by post-transcriptional reprogramming. Moreover, microRNA transfer by platelet MVs allows infiltration into tissues with limited cellular access such as solid tumors, thereby they not only modulate tumor progression but also provide a potential route for drug delivery. Understanding the precise mechanisms of horizontal transfer of platelet microRNAs under physiological and pathological conditions allows to design side-specific therapeutic (micro)RNA delivery systems. This review summarizes the current knowledge and the scientific evidence of horizontal microRNA transfer by platelets and platelet-derived MVs into vascular and non-vascular cells and its physiological consequences.

Extracellular Vesicles: Novel Opportunities to Understand and Detect Neoplastic Diseases

With a size range from 30 to 1000 nm, extracellular vesicles (EVs) are one of the smallest cell components able to transport biologically active molecules. They mediate intercellular communications and play a fundamental role in the maintenance of tissue homeostasis and pathogenesis in several types of diseases. In particular, EVs actively contribute to cancer initiation and progression, and there is emerging understanding of their role in creation of the metastatic niche. This fact underlies the recent exponential growth in EV research, which has improved our understanding of their specific roles in disease and their potential applications in diagnosis and therapy. EVs and their biomolecular cargo reflect the state of the diseased donor cells, and can be detected in body fluids and exploited as biomarkers in cancer and other diseases. Relatively few studies have been published on EVs in the veterinary field. This review provides an overview of the features and biology of EVs as well as recent developments in EV research including techniques for isolation and analysis, and will address the way in which the EVs released by diseased tissues can be studied and exploited in the field of veterinary pathology. Uniquely, this review emphasizes the important contribution that pathologists can make to the field of EV research: pathologists can help EV scientists in studying and confirming the role of EVs and their molecular cargo in diseased tissues and as biomarkers in liquid biopsies.

Effects and Side Effects of Platelet Transfusion

Aside from their canonical role in hemostasis, it is increasingly recognized that platelets have inflammatory functions and can regulate both adaptive and innate immune responses. The main topic this review aims to cover is the proinflammatory effects and side effects of platelet transfusion. Platelets prepared for transfusion are subject to stress injury upon collection, preparation, and storage. With these types of stress, they undergo morphologic, metabolic, and functional modulations which are likely to induce platelet activation and the release of biological response modifiers (BRMs). As a consequence, platelet concentrates (PCs) accumulate BRMs during processing and storage, and these BRMs are ultimately transfused alongside platelets. It has been shown that BRMs present in PCs can induce immune responses and posttransfusion reactions in the transfusion recipient. Several recent reports within the transfusion literature have investigated the concept of platelets as immune cells. Nevertheless, current and future investigations will face the challenge of encompassing the immunological role of platelets in the scope of transfusion.

Diets and Cellular-Derived Microparticles: Weighing a Plausible Link With Cerebral Small Vessel Disease

Cerebral small vessel disease (CSVD) represents a spectrum of pathological processes of various etiologies affecting the brain microcirculation that can trigger neuroinflammation and the subsequent neurodegenerative cascade. Prevalent with aging, CSVD is a recognized risk factor for stroke, vascular dementia, Alzheimer disease, and Parkinson disease. Despite being the most common neurodegenerative condition with cerebrocardiovascular axis, understanding about it remains poor. Interestingly, modifiable risk factors such as unhealthy diet including high intake of processed food, high-fat foods, and animal by-products are known to influence the non-neural peripheral events, such as in the gastrointestinal tract and cardiovascular stress through cellular inflammation and oxidation. One key outcome from such events, among others, includes the cellular activations that lead to elevated levels of endogenous cellular-derived circulating microparticles (MPs). MPs can be produced from various cellular origins including leukocytes, platelets, endothelial cells, microbiota, and microglia. MPs could act as microthrombogenic procoagulant that served as a plausible culprit for the vulnerable end-artery microcirculation in the brain as the end-organ leading to CSVD manifestations. However, little attention has been paid on the potential role of MPs in the onset and progression of CSVD spectrum. Corroboratively, the formation of MPs is known to be influenced by diet-induced cellular stress. Thus, this review aims to appraise the body of evidence on the dietary-related impacts on circulating MPs from non-neural peripheral origins that could serve as a plausible microthrombosis in CSVD manifestation as a precursor of neurodegeneration. Here, we elaborate on the pathomechanical features of MPs in health and disease states; relevance of dietary patterns on MP release; preclinical studies pertaining to diet-based MPs contribution to disease; MP level as putative surrogates for early disease biomarkers; and lastly, the potential of MPs manipulation with diet-based approach as a novel preventive measure for CSVD in an aging society worldwide.

Circulating platelets as liquid biopsy sources for cancer detection

Nucleic acids and proteins are shed into the bloodstream by tumor cells and can be exploited as biomarkers for the detection of cancer. In addition, cancer detection biomarkers can also be nontumor‐derived, having their origin in other organs and cell types. Hence, liquid biopsies provide a source of direct tumor cell‐derived biomolecules and indirect nontumor‐derived surrogate markers that circulate in body fluids or are taken up by circulating peripheral blood cells. The capacity of platelets to take up proteins and nucleic acids and alter their megakaryocyte‐derived transcripts and proteins in response to external signals makes them one of the richest liquid biopsy biosources. Platelets are the second most abundant cell type in peripheral blood and are routinely isolated through well‐established and fast methods in clinical diagnostics but their value as a source of cancer biomarkers is relatively recent. Platelets do not have a nucleus but have a functional spliceosome and protein translation machinery, to process RNA transcripts. Platelets emerge as important repositories of potential cancer biomarkers, including several types of RNAs (mRNA, miRNA, circRNA, lncRNA, and mitochondrial RNA) and proteins, and several preclinical studies have highlighted their potential as a liquid biopsy source for detecting various types and stages of cancer. Here, we address the usability of platelets as a liquid biopsy for the detection of cancer. We describe several studies that support the use of platelet biomarkers in cancer diagnostics and discuss what is still lacking for their implementation into the clinic.

Extracellular Vesicles Are Key Regulators of Tumor Neovasculature

Tumor progression involves a series of biologically important steps in which the crosstalk between cancer cells and the surrounding environment is an important issue. Angiogenesis is a key tumorigenic phenomenon for cancer progression. Tumor-related extracellular vesicles (EVs) modulate the tumor microenvironment (TME) through cell-to-cell communication. Tumor cells in a hypoxic TME release more EVs than cells in a normoxic environment due to uncontrollable tumor proliferation. Tumor-derived EVs in the TME influence endothelial cells (ECs), which then play multiple roles, contributing to tumor angiogenesis, loss of the endothelial vascular barrier by binding to ECs, and subsequent endothelial-to-mesenchymal transition. In contrast, they also indirectly induce tumor angiogenesis through the phenotype switching of various cells into cancer-associated fibroblasts, the activation of tumor-associated ECs and platelets, and remodeling of the extracellular matrix. Here, we review current knowledge regarding the involvement of EVs in tumor vascular-related cancer progression.

The role of extracellular vesicles in neointima formation post vascular injury

Pathological neointimal growth can develop in patients as a result of vascular injury following percutaneous coronary intervention and coronary artery bypass grafting using autologous saphenous vein, leading to arterial or vein graft occlusion. Neointima formation driven by intimal hyperplasia occurs as a result of a complex interplay between molecular and cellular processes involving different cell types including endothelial cells, vascular smooth muscle cells and various inflammatory cells. Therefore, understanding the intercellular communication mechanisms underlying this process remains of fundamental importance in order to develop therapeutic strategies to preserve endothelial integrity and vascular health post coronary interventions. Extracellular vesicles (EVs), including microvesicles and exosomes, are membrane-bound particles secreted by cells which mediate intercellular signalling in physiological and pathophysiological states, however their role in neointima formation is not fully understood. The purification and characterization techniques currently used in the field are associated with many limitations which significantly hinder the ability to comprehensively study the role of specific EV types and make direct functional comparisons between EV subpopulations. In this review, the current knowledge focusing on EV signalling in neointima formation post vascular injury is discussed.

Platelet Microparticle Controversial Role in Cancer

Platelet-derived microparticles (PMPs) are a group of micrometer-scale extracellular vesicles released by platelets upon activation that are responsible for the majority of microvesicles found in plasma. PMPs’ physiological properties and functions have long been investigated by researchers. In this regard, a noticeable area of studies has been devoted to evaluating the potential roles and effects of PMPs on cancer progression. Clinical and experimental evidence conflictingly implicates supportive and suppressive functions for PMPs regarding cancer. Many of these functions could be deemed as a cornerstone for future considerations of PMPs usage in cancer targeted therapy. This review discusses what is currently known about PMPs and provides insights for new and possible research directions for further grasping the intricate interplay between PMPs and cancer.

Platelets Extracellular Vesicles as Regulators of Cancer Progression-An Updated Perspective

Extracellular vesicles (EVs) are a diverse group of membrane-bound structures secreted in physiological and pathological conditions by prokaryotic and eukaryotic cells. Their role in cell-to-cell communications has been discussed for more than two decades. More attention is paid to assess the impact of EVs in cancer. Numerous papers showed EVs as tumorigenesis regulators, by transferring their cargo molecules (miRNA, DNA, protein, cytokines, receptors, etc.) among cancer cells and cells in the tumor microenvironment. During platelet activation or apoptosis, platelet extracellular vesicles (PEVs) are formed. PEVs present a highly heterogeneous EVs population and are the most abundant EVs group in the circulatory system. The reason for the PEVs heterogeneity are their maternal activators, which is reflected on PEVs size and cargo. As PLTs role in cancer development is well-known, and PEVs are the most numerous EVs in blood, their feasible impact on cancer growth is strongly discussed. PEVs crosstalk could promote proliferation, change tumor microenvironment, favor metastasis formation. In many cases these functions were linked to the transfer into recipient cells specific cargo molecules from PEVs. The article reviews the PEVs biogenesis, cargo molecules, and their impact on the cancer progression.

Mediating effects of platelet-derived extracellular vesicles on PM2.5-induced vascular endothelial injury

At present, PM_2.5 exposure has been considered as a major risk factor for cardiovascular disease. Most studies have focused on the toxic mechanism of PM_2.5 in direct contact with cells or biomolecules, only few studies have reported the toxic mechanism of PM_2.5 mediated by intercellular communication. Extracellular vesicles are the main carriers of intercellular communication and signal transduction in vivo, and play a vital role in the occurrence and development of cardiovascular disease. Therefore, the present research aimed to determine whether platelets-derived extracellular vesicles (P-EVs) secreted from PM_2.5-exposed platelets are transferred into the human umbilical vein endothelial cells (HUVECs) and mediated the PM_2.5-induced vascular endothelial injury by affecting normal cellular function. The result showed that P-EVs secreted from PM_2.5-exposed platelets significantly reduced the proliferation promoting effect of normal P-EVs on vascular endothelium by decreasing the effective factors promoting vascular endothelial growth. Meanwhile, the levels of intercellular adhesion molecules, proinflammatory factors (ICAM-1, IL-6, and TNF-α) and the ROS level of HUVECs were markedly elevated. In addition, the apoptotic rate was increased via up-regulating the protein level of cytochrome-C(Cyt C), Bax, cleaved caspase-3 and down-regulating Bcl-2 in HUVECs, indicating that mitochondrial apoptotic pathway was activated by P-EVs secreted from PM_2.5-exposed platelets. Further, the expression level of P-EVs targeted miRNAs in HUVECs was altered, indicating that miRNAs released from P-EVs were transferred to HUVECs and regulated the cellular function, while PM_2.5 could inhibit this regulatory effect. In summary, these results demonstrate that the P-EVs secreted from PM_2.5-exposed platelets can enter the HUVECs, which mediate the PM_2.5-induced vascular endothelial injury. These findings provide a new perspective and theoretical basis for further exploring the mechanism of cardiovascular damage caused by PM_2.5 exposure.

Glioma-derived exosomes drive the differentiation of neural stem cells to astrocytes

Exosomes appear to be effective inter-cellular communicators delivering several types of molecules, such as proteins and RNAs, suggesting that they could influence neural stem cell (NSC) differentiation. Our RNA sequencing studies demonstrated that the RNAs related to cell proliferation and astrocyte differentiation were upregulated in human mesenchymal stem cells (hMSC) when co-cultured with exosomes obtained from the culture medium of human glioma cells (U87). Metallothionein 3 and elastin genes, which are related to cell proliferation, increased 10 and 7.2 fold, respectively. Expression of genes for astrocyte differentiation, such as tumor growth factor alpha, induced protein 3 of the NOTCH1 family, colony stimulating factor and interleukin 6 of the STAT3 family and Hes family bHLH transcription factor 1 also increased by 2.3, 10, 4.7 and 2.9 fold, respectively. We further examined the effects of these exosomes on rat fetal neural stem cell (rNSC) differentiation using the secreted exosomes from U87 glioma cells or exosomes from U87 cells that were stimulated with interleukin 1β (IL-1β). The rNSCs, extracted from rat brains at embryonic day 14 (E14), underwent a culture protocol that normally leads to predominant (~90%) differentiation to ODCs. However, in the presence of the exosomes from untreated or IL-1β-treated U87 cells, significantly more cells differentiated into astrocytes, especially in the presence of exosomes obtained from the IL-1β-challenged glioma cells. Moreover, glioma-derived exosomes appeared to inhibit rNSC differentiation into ODCs or astrocytes as indicated by a significantly increased population of unlabeled cells. A portion of the resulting astrocytes co-expressed both CD133 and glial fibrillary acidic protein (GFAP) suggesting that exosomes from U87 cells could promote astrocytic differentiation of NSCs with features expected from a transformed cell. Our data clearly demonstrated that exosomes secreted by human glioma cells provide a strong driving force for rat neural stem cells to differentiate into astrocytes, uncovering potential pathways and therapeutic targets that might control this aggressive tumor type.

Microparticles in the pathogenesis of TB: Novel perspectives for diagnostic and therapy management of Mycobacterium tuberculosis infection

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, usually chronic and has a progressive clinical course. Despite the availability of effective chemotherapy, TB is a leading killer of young adults worldwide and the global multi-drug resistant TB is reaching epidemic proportions. Interrupt transmission through early detection and treatment of the patients is a main element of the drug-resistant TB control strategy. However, many drugable targets in pathogens are already inhibited by current antibiotics and there is not a biomarker that indicate normal or pathogenic biological processes, or pharmacological responses to therapeutic intervention. Studies directed at evaluate key elements of host response to infection may identify biomarkers with measurable characteristics that indicate pathogenic biological processes. Cell-derived microparticles (MPs) are membrane-coated vesicles that represent subcellular elements and have been identified increasingly in a broad range of diseases and emerging as potential novel biomarker to pathological processes. In addition, MPs carry contents from their cells of origin as bioactive molecules as cytokines, enzymes, surface receptors, antigens and genetic information and may provide a means of communication between cells. Molecules-loaded MPs may interplay with the immune system and therefore can acts on inflammation, cell activation and migration. Therefore, MPs may be an important factor to immune process during Mtb infection, especially in pulmonary granulomas and influence the outcome of infection. Their characterization may facilitate an appropriate diagnosis, optimize pharmacological strategies and might be further explored as potential targets for future clinical interventions.

Characterization and function of medium and large extracellular vesicles from plasma and urine by surface antigens and Annexin V

Background

Extracellular vesicles (EVs) are released by most cell types and are involved in multiple basic biological processes. Medium/large EVs (m/lEVs), which are of a different size from exosomes, play an important role in the coagulation in blood, and are secreted from cancer cells, etc., suggesting functions related to malignant transformation. The m/lEVs levels in blood or urine may help unravel pathophysiological findings in many diseases. However, it remains unclear how many naturally-occurring m/lEV subtypes exist as well as how their characteristics and functions differ from one another.

Methods

We used the blood and urinal sample from each 10 healthy donors for analysis. Using a flow cytometer, we focus on characterization of EVs with large sizes (>200 nm) that are different from exosomes. We also searched for a membrane protein for characterization with a flow cytometer using shotgun proteomics. We then identified m/lEVs pelleted from plasma and urine samples by differential centrifugation and characterized by flow cytometry.

Results

Using proteomic profiling, we identified several proteins involved in m/lEV biogenesis including adhesion molecules, peptidases and exocytosis regulatory proteins. In healthy human plasma, we could distinguish m/lEVs derived from platelets, erythrocytes, monocytes/macrophages, T and B cells, and vascular endothelial cells with more than two positive surface antigens. The ratio of phosphatidylserine appearing on the membrane surface differed depending on the cell-derived m/lEVs. In urine, 50% of m/lEVs were Annexin V negative but contained various membrane peptidases derived from renal tubular villi. Urinary m/lEVs, but not plasma m/lEVs, showed peptidase activity. The knowledge of the new characteristics is considered to be useful as a diagnostic material and the newly developed method suggests the possibility of clinical application.

Extracellular Vesicles in the Blood of Dogs with Cancer-A Preliminary Study

Extracellular vesicles (EVs) are a heterogeneous population of submicron-sized structures released during the activation, proliferation, or apoptosis of various types of cells. Due to their size, their role in cell-to-cell communication in cancer is currently being discussed. In blood, the most abundant population of EVs is platelet-derived EVs (PEVs). The aim of this study was to estimate the absolute number and the origin of EVs in the blood of healthy dogs and of dogs with various types of cancer. The EV absolute number and cellular origin were examined by flow cytometry technique. EVs were classified on the basis of surface annexin V expression (phosphatidylserine PS+) and co-expression of specific cellular markers (CD61, CD45, CD3, CD21). The number of PEVs was significantly higher in dogs with cancer (median: 409/µL, range: 42-2748/µL vs. median: 170/µL, range: 101-449/µL in controls). The numbers of EVs derived from leukocytes (control median: 86/µL, range: 40-240/µL; cancer median: 443/µL, range: 44-3 352/µL) and T cells (control median: 5/µL, range: 2-66/µL; cancer median: 108/µL, range: 3-1735/µL) were higher in dogs with neoplasia compared to healthy controls. The estimation of PEV and leukocyte-derived EV counts may provide a useful biological marker in dogs with cancer.