PLD2 is enriched on exosomes and its activity is correlated to the release of exosomes

Fluorescent, phosphorescent, magnetic resonance contrast and radioactive tracer labelling of extracellular vesicles

This review focusses on the significance of fluorescent, phosphorescent labelling and tracking of extracellular vesicles (EVs) for unravelling their biology, pathophysiology, and potential diagnostic and therapeutic uses. Various labeling strategies, such as lipid membrane, surface protein, luminal, nucleic acid, radionuclide, quantum dot labels, and metal complex-based stains, are evaluated for visualizing and characterizing EVs. Direct labelling with fluorescent lipophilic dyes is simple but generally lacks specificity, while surface protein labelling offers selectivity but may affect EV-cell interactions. Luminal and nucleic acid labelling strategies have their own advantages and challenges. Each labelling approach has strengths and weaknesses, which require a suitable probe and technique based on research goals, but new tetranuclear polypyridylruthenium(II) complexes as phosphorescent probes have strong phosphorescence, selective staining, and stability. Future research should prioritize the design of novel fluorescent probes and labelling platforms that can significantly enhance the efficiency, accuracy, and specificity of EV labeling, while preserving their composition and functionality. It is crucial to reduce false positive signals and explore the potential of multimodal imaging techniques to gain comprehensive insights into EVs.

MicroRNA Nano-Shuttles: Engineering Extracellular Vesicles as a Cutting-Edge Biotechnology Platform for Clinical Use in Therapeutics

Extracellular vesicles (EVs) are nano-sized, membranous transporters of various active biomolecules with inflicting phenotypic capabilities, that are naturally secreted by almost all cells with a promising vantage point as a potential leading drug delivery platform. The intrinsic characteristics of their low toxicity, superior structural stability, and cargo loading capacity continue to fuel a multitude of research avenues dedicated to loading EVs with therapeutic and diagnostic cargos (pharmaceutical compounds, nucleic acids, proteins, and nanomaterials) in attempts to generate superior natural nanoscale delivery systems for clinical application in therapeutics. In addition to their well-known role in intercellular communication, EVs harbor microRNAs (miRNAs), which can alter the translational potential of receiving cells and thus act as important mediators in numerous biological and pathological processes. To leverage this potential, EVs can be structurally engineered to shuttle therapeutic miRNAs to diseased recipient cells as a potential targeted 'treatment' or 'therapy'. Herein, this review focuses on the therapeutic potential of EV-coupled miRNAs; summarizing the biogenesis, contents, and function of EVs, as well as providing both a comprehensive discussion of current EV loading techniques and an update on miRNA-engineered EVs as a next-generation platform piloting benchtop studies to propel potential clinical translation on the forefront of nanomedicine.

Treating cancer through modulating exosomal protein loading and function: The prospects of natural products and traditional Chinese medicine

Exosomes, small yet vital extracellular vesicles, play an integral role in intercellular communication. They transport critical components, such as proteins, lipid bilayers, DNA, RNA, and glycans, to target cells. These vesicles are crucial in modulating the extracellular matrix and orchestrating signal transduction processes. In oncology, exosomes are pivotal in tumor growth, metastasis, drug resistance, and immune modulation within the tumor microenvironment. Exosomal proteins, noted for their stability and specificity, have garnered widespread attention. This review delves into the mechanisms of exosomal protein loading and their impact on tumor development, with a focus on the regulatory effects of natural products and traditional Chinese medicine on exosomal protein loading and function. These insights not only offer new strategies and methodologies for cancer treatment but also provide scientific bases and directions for future clinical applications.

Exosomes as a therapeutic tool to promote neurorestoration and cognitive function in neurological conditions: Achieve two ends with a single effort

Exosomes possess a significant role in intercellular communications. In the nervous system, various neural cells release exosomes that not only own a role in intercellular communications but also eliminate the waste of cells, maintain the myelin sheath, facilitate neurogenesis, and specifically assist in normal cognitive function. In neurological conditions including Parkinson's disease (PD), Alzheimer's disease (AD), traumatic brain injury (TBI), and stroke, exosomal cargo like miRNAs take part in the sequela of conditions and serve as a diagnostic tool of neurological disorders, too. Exosomes are not only a diagnostic tool but also their inhibition or administration from various sources like mesenchymal stem cells and serum, which have shown a worthy potential to treat multiple neurological disorders. In addition to neurodegenerative manifestations, cognitive deficiencies are an integral part of neurological diseases, and applying exosomes in improving both aspects of these diseases has been promising. This review discusses the status of exosome therapy in improving neurorestorative and cognitive function following neurological disease.

Extracellular Vesicles in Malaria: Shedding Light on Pathogenic Depths

Malaria, a life-threatening infectious disease caused by Plasmodium falciparum, remains a significant global health challenge, particularly in tropical and subtropical regions. The epidemiological data for 2021 revealed a staggering toll, with 247 million reported cases and 619,000 fatalities attributed to the disease. This formidable global health challenge continues to perplex researchers seeking a comprehensive understanding of its pathogenesis. Recent investigations have unveiled the pivotal role of extracellular vesicles (EVs) in this intricate landscape. These tiny, membrane-bound vesicles, secreted by diverse cells, emerge as pivotal communicators in malaria's pathogenic orchestra. This Review delves into the multifaceted roles of EVs in malaria pathogenesis, elucidating their impact on disease progression and immune modulation. Insights into EV involvement offer potential therapeutic and diagnostic strategies. Integrating this information identifies targets to mitigate malaria's global impact. Moreover, this Review explores the potential of EVs as diagnostic biomarkers and therapeutic targets in malaria. By deciphering the intricate dialogue facilitated by these vesicles, new avenues for intervention and novel strategies for disease management may emerge.

High-fat diets: You are what you eat….your extracellular vesicles too!

Recent works indicate that the lipid composition of extracellular vesicles (EVs) can modify their biological functions and their incorporation into recipient cells. In particular high-fat diets affect EV biogenesis, EV lipid composition, EV targeting and consequently the cross-talk between tissues. This review connects different research topics to show that a vicious circle is established during the development of high-fat diet-induced obesity, connecting the alteration of lipid metabolism, the composition of extracellular vesicles and the spread of deleterious lipids between tissues, which participates in NAFLD/NASH and diabetes development. According to the studies described in this review, it is urgent to take an interest in this question as the modulation of EV lipid composition could be an important factor to take into account during the therapeutic management of patients suffering from metabolic syndrome and related pathologies such as obesity and diabetes. Furthermore, as lipid modification of EVs is a strategy currently being tested to enable better integration into their target tissue or cell, it is important to consider the impact of these lipid modifications on the homeostasis of these targets.

Maternal microbiota communicates with the fetus through microbiota-derived extracellular vesicles

BACKGROUND

Reports regarding the presence of bacteria in the fetal environment remain limited and controversial. Recently, extracellular vesicles secreted by the human gut microbiota have emerged as a novel mechanism for host-microbiota interaction. We aimed to investigate the presence of bacterial extracellular vesicles in the fetal environment during healthy pregnancies and determine whether extracellular vesicles derived from the gut microbiota can cross biological barriers to reach the fetus.

RESULTS

Bacterial extracellular vesicles were detectable in the amniotic fluid of healthy pregnant women, exhibiting similarities to extracellular vesicles found in the maternal gut microbiota. In pregnant mice, extracellular vesicles derived from human maternal gut microbiota were found to reach the intra-amniotic space.

CONCLUSIONS

Our findings reveal maternal microbiota-derived extracellular vesicles as an interaction mechanism between the maternal microbiota and fetus, potentially playing a pivotal role in priming the prenatal immune system for gut colonization after birth. Video Abstract.

Role of lipid signalling in extracellular vesicles-mediated cell-to-cell communication

Lipid signalling plays a crucial role in extracellular vesicle (EV)-mediated cell-to-cell communication. Extracellular vesicles are small membrane-bound structures released by various cell types into the extracellular environment. They include exosomes, microvesicles, and apoptotic bodies. These vesicles contain a variety of bioactive molecules, including proteins, nucleic acids (such as miRNAs and mRNAs), and lipids. Lipids are important components of EVs and are involved in various aspects of their biogenesis, cargo sorting, and functional effects on target cells. In this review, we will discuss how lipid signalling is involved in EV-mediated cell-to-cell communication. In summary, lipid signalling is intricately involved in extracellular vesicle-mediated cell-to-cell communication. The lipid composition of EVs influences their biogenesis, cargo sorting, interactions with target cells, and functional effects on recipient cells. Understanding the role of lipids in EV-mediated communication is essential for deciphering the mechanisms underlying intercellular signalling and developing potential therapeutic strategies based on EVs.

Targeting tumor-derived exosome-mediated premetastatic niche formation: The metastasis-preventive value of traditional Chinese medicine

Tumor-derived exosome (TDE)-mediated premetastatic niche (PMN) formation is a potential mechanism underlying the organotropic metastasis of primary tumors. Traditional Chinese medicine (TCM) has shown considerable success in preventing and treating tumor metastasis. However, the underlying mechanisms remain elusive. In this review, we discussed PMN formation from the perspectives of TDE biogenesis, cargo sorting, and TDE recipient cell alterations, which are critical for metastatic outgrowth. We also reviewed the metastasis-preventive effects of TCM, which act by targeting the physicochemical materials and functional mediators of TDE biogenesis, regulating the cargo sorting machinery and secretory molecules in TDEs, and targeting the TDE-recipient cells involved in PMN formation.

siRNA screening reveals that SNAP29 contributes to exosome release

Cells release extracellular vesicles (EVs) of different sizes. Small EVs (< 200 nm) can originate from the fusion of multivesicular bodies with the plasma membrane, i.e. exosomes, and from budding of the plasma membrane, i.e. small ectosomes. To investigate the molecular machinery required for the release of small EVs, we developed a sensitive assay based on incorporation of radioactive cholesterol in EV membranes and used it in a siRNA screening. The screening showed that depletion of several SNARE proteins affected the release of small EVs. We focused on SNAP29, VAMP8, syntaxin 2, syntaxin 3 and syntaxin 18, the depletion of which reduced the release of small EVs. Importantly, this result was verified using gold standard techniques. SNAP29 depletion resulted in the largest effect and was further investigated. Immunoblotting analysis of small EVs showed that the release of several proteins considered to be associated with exosomes like syntenin, CD63 and Tsg101 was reduced, while the level of several proteins that have been shown to be released in ectosomes (annexins) or by secretory autophagy (LC3B and p62) was not affected by SNAP29 depletion. Moreover, these proteins appeared in different fractions when the EV samples were further separated by a density gradient. These results suggest that SNAP29 depletion mainly affects the secretion of exosomes. To investigate how SNAP29 affects exosome release, we used microscopy to study the distribution of MBVs using CD63 labelling and CD63-pHluorin to detect fusion events of MVBs with the plasma membrane. SNAP29 depletion caused a redistribution of CD63-labelled compartments but did not change the number of fusion events. Further experiments are therefore needed to fully understand the function of SNAP29. To conclude, we have developed a novel screening assay that has allowed us to identify several SNAREs involved in the release of small EVs.

Role of adipocyte-derived extracellular vesicles during the progression of liver inflammation to hepatocellular carcinoma

Extracellular vesicles are membrane-bound cargos that vary in size and are stably transported through various bodily fluids. Extracellular vesicles communicate information between the cells and organs. Extracellular vesicles from the diseased cells alter cellular responses of the recipient cells contributing to disease progression. In obesity, adipocytes become hypertrophic and the extracellular vesicles from these dysfunctional adipocytes showed altered cargo contents instigating pathophysiological response leading to chronic liver diseases. In this review, the role of adipocyte-derived extracellular vesicles on the progression of liver inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma are extensively discussed. Newer approaches are crucial to take advantage of extracellular vesicles and their content as biomarkers to diagnose initial liver inflammation before reaching to an irreversible liver failure stage.

Challenges and strategies: Scalable and efficient production of mesenchymal stem cells-derived exosomes for cell-free therapy

Exosomes are small membrane vesicles secreted by most cell types, and widely exist in cell supernatants and various body fluids. They can transmit numerous bioactive elements, such as proteins, nucleic acids, and lipids, to affect the gene expression and function of recipient cells. Mesenchymal stem cells (MSCs) have been confirmed to be a potentially promising therapy for tissue repair and regeneration. Accumulating studies demonstrated that the predominant regenerative paradigm of MSCs transplantation was the paracrine effect but not the differentiation effect. Exosomes secreted by MSCs also showed similar therapeutic effects as their parent cells and were considered to be used for cell-free regenerative medicine. However, the inefficient and limited production has hampered their development for clinical translation. In this review, we summarize potential methods to efficiently promote the yield of exosomes. We mainly focus on engineering the process of exosome biogenesis and secretion, altering the cell culture conditions, cell expansion through 3D dynamic culture and the isolation of exosomes. In addition, we also discuss the application of MSCs-derived exosomes as therapeutics in disease treatment.

Dendritic cell-derived exosomes: A new horizon in personalized cancer immunotherapy?

Dendritic cells (DCs) release nanometer-sized membrane vesicles known as dexosomes, containing different molecules, particularly proteins, for presenting antigens, i.e., major histocompatibility complex (MHC)-I/II and CD86. Dexosomes can, directly and indirectly, stimulate antigen-reactive CD8⁺ and CD4⁺ T cell responses. Antigen-loaded dexosomes can lead to the development of potent anti-tumoral immune responses. Notably, developing dexosome-based cell-free vaccines could serve as a new vaccination platform in the era of immunotherapy for various cancers. Furthermore, combining dexosomes vaccination strategies with other treatment approaches can considerably increase tumor-specific T cell responses. Herein, we aimed to review how dexosomes interact with immune cells, e.g., CD4⁺ and CD8⁺ T cells and natural killer (NK) cells. Besides, we discussed the limitations of this approach and suggested potential strategies to improve its effectiveness for affected patients.

Extracellular Vesicles and Their Membranes: Exosomes vs. Virus-Related Particles

Cells produce nanosized lipid membrane-enclosed vesicles which play important roles in intercellular communication. Interestingly, a certain type of extracellular vesicle, termed exosomes, share physical, chemical, and biological properties with enveloped virus particles. To date, most similarities have been discovered with lentiviral particles, however, other virus species also frequently interact with exosomes. In this review, we will take a closer look at the similarities and differences between exosomes and enveloped viral particles, with a focus on events taking place at the vesicle or virus membrane. Since these structures present an area with an opportunity for interaction with target cells, this is relevant for basic biology as well as any potential research or medical applications.

The role of extracellular vesicles in intercellular communication in human reproduction

Embryo-maternal cross-talk has emerged as a vitally important process for embryo development and implantation, which is driven by secreted factors and extracellular vesicles (EVs). The EV cargo of bioactive molecules significantly influences target cells and primes them for critical stages of reproductive biology, including embryo development, adhesion, and implantation. Recent research has suggested that EVs and their cargo represent a powerful non-invasive tool that can be leveraged to assess embryo and maternal tissue quality during assisted reproduction treatments. Here, we review the current scientific literature regarding the intercellular cross-talk between embryos and maternal tissues from fertilization to implantation, focusing on human biology and signaling mechanisms identified in animal models.

Research progress of extracellular vesicles as biomarkers in immunotherapy for non-small cell lung cancer

Lung cancer is one of the most severe forms of malignancy and a leading cause of cancer-related death worldwide, of which non-small cell lung cancer (NSCLC) is the most primary type observed in the clinic. NSCLC is mainly treated with surgery, radiotherapy, and chemotherapy. Additionally, targeted therapy and immunotherapy have also shown promising results. Several immunotherapies, including immune checkpoint inhibitors, have been developed for clinical use and have benefited patients with NSCLC. However, immunotherapy faces several challenges like poor response and unknown effective population. It is essential to identify novel predictive markers to further advance precision immunotherapy for NSCLC. Extracellular vesicles (EVs) present an important research direction. In this review, we focus on the role of EVs as a biomarker in NSCLC immunotherapy considering various perspectives, including the definition and properties of EVs, their role as biomarkers in current NSCLC immunotherapy, and different EV components as biomarkers in NSCLC immunotherapy research. We describe the cross-talk between the role of EVs as biomarkers and novel technical approaches or research concepts in NSCLC immunotherapy, such as neoadjuvants, multi-omics analysis, and the tumour microenvironment. This review will provide a reference for future research to improve the benefits of immunotherapy for patients with NSCLC.

Phospholipase D and cancer metastasis: A focus on exosomes

In mammals, phospholipase D (PLD) enzymes involve 6 isoforms, of which only three have established lipase activity to produce the signaling lipid phosphatidic acid (PA). This phospholipase activity has been postulated to contribute to cancer progression for over three decades now, but the exact mechanisms involved have yet to be uncovered. Indeed, using various models, an altered PLD activity has been proposed altogether to increase cell survival rate, promote angiogenesis, boost rapamycin resistance, and favor metastasis. Although for some part, the molecular pathways by which this increase in PA is pro-oncogenic are partially known, the pleiotropic functions of PA make it quite difficult to distinguish which among these simple signaling pathways is responsible for each of these PLD facets. In this review, we will describe an additional potential contribution of PA generated by PLD1 and PLD2 in the biogenesis, secretion, and uptake of exosomes. Those extracellular vesicles are now viewed as membrane vehicles that carry informative molecules able to modify the fate of receiving cells at distance from the original tumor to favor homing of metastasis. The perspectives for a better understanding of these complex role of PLDs will be discussed.

Exosome engineering in cell therapy and drug delivery

Cell-derived exosomes have opened new horizons in modern therapy for advanced drug delivery and therapeutic applications, due to their key features such as low immunogenicity, high physicochemical stability, capacity to penetrate into tissues, and the innate capacity to communicate with other cells over long distances. Exosome-based liquid biopsy has been potentially used for the diagnosis and prognosis of a range of disorders. Exosomes deliver therapeutic agents, including immunological modulators, therapeutic drugs, and antisense oligonucleotides to certain targets, and can be used as vaccines, though their clinical application is still far from reality. Producing exosomes on a large-scale is restricted to their low circulation lifetime, weak targeting capacity, and inappropriate controls, which need to be refined before being implemented in practice. Several bioengineering methods have been used for refining therapeutic applications of exosomes and promoting their effectiveness, on the one hand, and addressing the existing challenges, on the other. In the short run, new diagnostic platforms and emerging therapeutic strategies will further develop exosome engineering and therapeutic potential. This requires a thorough analysis of exosome engineering approaches along with their merits and drawbacks, as outlined in this paper. The present study is a comprehensive review of novel techniques for exosome development in terms of circulation time in the body, targeting capacity, and higher drug loading/delivery efficacies.

The potential of sertoli cells (SCs) derived exosomes and its therapeutic efficacy in male reproductive disorders

In the male reproductive system, seminiferous tubules in testis are lined by a complex stratified epithelium containing two distinct populations of cells, spermatogenic cells that develop into spermatozoa, and sertoli cells (SCs) that mainly support and nourish spermatogenic cell lineage as well as exerting powerful effect on men reproductive capacity. Different varieties of proteins, hormones, exosomes and growth factors are secreted by SCs. There are different kinds of junctions found between SCs called BTB. It was elucidated that complete absence of BTB or its dysfunction leads to infertility. To promote spermatogenesis, crosstalk of SCs with spermatogenic cells plays an important role. The ability of SCs to support germ cell productivity and development is related to its various products carrying out several functions. Exosomes (EXOs) are one of the main EVs with 30-100 nm size generating from endocytic pathway. They are produced in different parts of male reproductive system including epididymis, prostate and SCs. The most prominent characteristics of SC-based exosomes is considered mutual interaction of sertoli cells with spermatogonial stem cells and Leydig cells mainly through establishment of intercellular communication. Exosomes have gotten a lot of interest because of their role in pathobiological processes and as a cell free therapy which led to developing multiple exosome isolation methods based on different principles. Transmission of nucleic acids, proteins, and growth factors via SC-based exosomes and exosomal miRNAs are proved to have potential to be valuable biomarkers in male reproductive disease. Among testicular abnormalities, non-obstructive azoospermia and testicular cancer have been more contributed with SCs performance. The identification of key proteins and miRNAs involved in the signaling pathways related with spermatogenesis, can serve as diagnostic and regenerative targets in male infertility.

How Do Extracellular Vesicles Play a Key Role in the Maintenance of Bone Homeostasis and Regeneration? A Comprehensive Review of Literature

The maintenance of bone homeostasis includes both bone resorption by osteoclasts and bone formation by osteoblasts. These two processes are in dynamic balance to maintain a constant amount of bone for accomplishing its critical functions in daily life. Multiple cell type communications are involved in these two complex and continuous processes. In recent decades, an increasing number of studies have shown that osteogenic and osteoclastic extracellular vesicles play crucial roles in regulating bone homeostasis through paracrine, autosecretory and endocrine signaling. Elucidating the functional roles of extracellular vesicles in the maintenance of bone homeostasis may contribute to the design of new strategies for bone regeneration. Hence, we review the recent understandings of the classification, production process, extraction methods, structure, contents, functions and applications of extracellular vesicles in bone homeostasis. We highlight the contents of various bone-derived extracellular vesicles and their interactions with different cells in the bone microenvironment during bone homeostasis. We also summarize the recent advances in EV-loaded biomaterial scaffolds for bone regeneration and repair.

Exosomal MicroRNAs as Novel Cell-Free Therapeutics in Tissue Engineering and Regenerative Medicine

Extracellular vesicles (EVs) are membrane-bound vesicles (50–1000 nm) that can be secreted by all cell types. Microvesicles and exosomes are the major subsets of EVs that exhibit the cell–cell communications and pathological functions of human tissues, and their therapeutic potentials. To further understand and engineer EVs for cell-free therapy, current developments in EV biogenesis and secretion pathways are discussed to illustrate the remaining gaps in EV biology. Specifically, microRNAs (miRs), as a major EV cargo that exert promising therapeutic results, are discussed in the context of biological origins, sorting and packing, and preclinical applications in disease progression and treatments. Moreover, advanced detection and engineering strategies for exosomal miRs are also reviewed. This article provides sufficient information and knowledge for the future design of EVs with specific miRs or protein cargos in tissue repair and regeneration.

Scalable Production of Extracellular Vesicles and Its Therapeutic Values: A Review

Extracellular vesicles (EVs) are minute vesicles with lipid bilayer membranes. EVs are secreted by cells for intercellular communication. Recently, EVs have received much attention, as they are rich in biological components such as nucleic acids, lipids, and proteins that play essential roles in tissue regeneration and disease modification. In addition, EVs can be developed as vaccines against cancer and infectious diseases, as the vesicle membrane has an abundance of antigenic determinants and virulent factors. EVs for therapeutic applications are typically collected from conditioned media of cultured cells. However, the number of EVs secreted by the cells is limited. Thus, it is critical to devise new strategies for the large-scale production of EVs. Here, we discussed the strategies utilized by researchers for the scalable production of EVs. Techniques such as bioreactors, mechanical stimulation, electrical stimulation, thermal stimulation, magnetic field stimulation, topographic clue, hypoxia, serum deprivation, pH modification, exposure to small molecules, exposure to nanoparticles, increasing the intracellular calcium concentration, and genetic modification have been used to improve the secretion of EVs by cultured cells. In addition, nitrogen cavitation, porous membrane extrusion, and sonication have been utilized to prepare EV-mimetic nanovesicles that share many characteristics with naturally secreted EVs. Apart from inducing EV production, these upscaling interventions have also been reported to modify the EVs’ cargo and thus their functionality and therapeutic potential. In summary, it is imperative to identify a reliable upscaling technique that can produce large quantities of EVs consistently. Ideally, the produced EVs should also possess cargo with improved therapeutic potential.

Emerging Role of Edible Exosomes-Like Nanoparticles (ELNs) as Hepatoprotective Agents

Liver diseases are responsible for over 2 million deaths each year and the number is rapidly increasing. There is a strong link between edibles, gut microbiota, liver fat and the liver damage. There are very limited therapeutic options for treatment specifically for Alcoholic liver disease (ALD) and Non-Alcoholic liver disease (NAFLD). Recently, identified Edible Exosomes-like nanoparticles (ELNs) are plant derived membrane bound particles, released by microvesicular bodies for cellular communication and regulate immune responses against many pathogens. Many studies have identified their role as hepatoprotective agent as they carry bioactive material as cargoes which are transferred to recipient cells and affect various biological functions in liver. They are also known to carry specific miRNA, which increases the copy number of beneficial bacteria and the production of lactic acid metabolites in gut and hence restrains from liver injury through portal vein. Few in-vitro studies also have been reported about the anti-inflammatory, anti-oxidant and detoxification properties of ELNs which again protects the liver. The properties such as small size, biocompatibility, stability, low toxicity and non-immunogenicity make ELNs as a better therapeutic option. But, till now, studies on the effect of ELNs as therapeutics are still at its infancy yet promising. Here we discuss about the isolation, characterization, their role in maintaining the gut microbiome and liver homeostasis. Also, we give an outline about the latest advances in ELNs modifications, its biological effects, limitations and we propose the future prospective of ELNs as therapeutics.

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.

Extracellular Vesicles and Cancer Therapy: Insights into the Role of Oxidative Stress

Oxidative stress plays a significant role in cancer development and cancer therapy, and is a major contributor to normal tissue injury. The unique characteristics of extracellular vesicles (EVs) have made them potentially useful as a diagnostic tool in that their molecular content indicates their cell of origin and their lipid membrane protects the content from enzymatic degradation. In addition to their possible use as a diagnostic tool, their role in how normal and diseased cells communicate is of high research interest. The most exciting area is the association of EVs, oxidative stress, and pathogenesis of numerous diseases. However, the relationship between oxidative stress and oxidative modifications of EVs is still unclear, which limits full understanding of the clinical potential of EVs. Here, we discuss how EVs, oxidative stress, and cancer therapy relate to one another; how oxidative stress can contribute to the generation of EVs; and how EVs’ contents reveal the presence of oxidative stress. We also point out the potential promise and limitations of using oxidatively modified EVs as biomarkers of cancer and tissue injury with a focus on pediatric oncology patients.

Exosome-Mediated Immunosuppression in Tumor Microenvironments

Exosomes are membranous structures secreted by nearly all cell types. As critical messengers for intercellular communication, exosomes deliver bioactive cargoes to recipient cells and are involved in multiple physiopathological processes, including immunoregulation. Our pioneering study revealed that cancer cells release programmed death-ligand 1-positive exosomes into the circulation to counter antitumor immunity systemically via T cells. Tumor cell-derived exosomes (TDEs) also play an immunosuppressive role in other immunocytes, including dendritic cells (DCs), macrophages, natural killer (NK) cells, and myeloid-derived suppressor cells (MDSCs). Moreover, exosomes secreted by nontumor cells in the tumor microenvironments (TMEs) also exert immunosuppressive effects. This review systematically provides a summary of the immunosuppression induced by exosomes in tumor microenvironments, which modulates tumor growth, invasion, metastasis, and immunotherapeutic resistance. Additionally, therapeutic strategies targeting the molecular mechanism of exosome-mediated tumor development, which may help overcome several obstacles, such as immune tolerance in oncotherapy, are also discussed. Detailed knowledge of the specific functions of exosomes in antitumor immunity may contribute to the development of innovative treatments.

Current Knowledge on Exosome Biogenesis, Cargo-Sorting Mechanism and Therapeutic Implications

Extracellular vesicles (EVs) are nanoscale membrane vesicles released by donor cells that can be taken up by recipient cells. The study of EVs has the potential to identify unknown cellular and molecular mechanisms in intercellular communication and disease. Exosomes, with an average diameter of ≈100 nanometers, are a subset of EVs. Different molecular families have been shown to be involved in the formation of exosomes and subsequent secretion of exosomes, which largely leads to the complexity of the form, structure and function of exosomes. In addition, because of their low immunogenicity and ability to transfer a variety of bioactive components to recipient cells, exosomes are regarded as effective drug delivery systems. This review summarizes the known mechanisms of exosomes biogenesis, cargo loading, exosomes release and bioengineering, which is of great importance for further exploration into the clinical applications of EVs.

Targeting the liver X receptor with dendrogenin A differentiates tumour cells to secrete immunogenic exosome-enriched vesicles

Tumour cells are characterized by having lost their differentiation state. They constitutively secrete small extracellular vesicles (sEV) called exosomes when they come from late endosomes. Dendrogenin A (DDA) is an endogenous tumour suppressor cholesterol‐derived metabolite. It is a new class of ligand of the nuclear Liver X receptors (LXR) which regulate cholesterol homeostasis and immunity. We hypothesized that DDA, which induces tumour cell differentiation, inhibition of tumour growth and immune cell infiltration into tumours, could functionally modify sEV secreted by tumour cells. Here, we have shown that DDA differentiates tumour cells by acting on the LXRβ. This results in an increased production of sEV (DDA‐sEV) which includes exosomes. The DDA‐sEV secreted from DDA‐treated cells were characterized for their content and activity in comparison to sEV secreted from control cells (C‐sEV). DDA‐sEV were enriched, relatively to C‐sEV, in several proteins and lipids such as differentiation antigens, “eat‐me” signals, lipidated LC3 and the endosomal phospholipid bis(monoacylglycero)phosphate, which stimulates dendritic cell maturation and a Th1 T lymphocyte polarization. Moreover, DDA‐sEV inhibited the growth of tumours implanted into immunocompetent mice compared to control conditions. This study reveals a pharmacological control through a nuclear receptor of exosome‐enriched tumour sEV secretion, composition and immune function. Targeting the LXR may be a novel way to reprogram tumour cells and sEV to stimulate immunity against cancer.

The implications of exosomes in pregnancy: emerging as new diagnostic markers and therapeutics targets

Extracellular vehicles (EVs) are a heterogeneous group of cell and membranous particles originating from different cell compartments. EVs participate in many essential physiological functions and mediate fetal-maternal communications. Exosomes are the smallest unit of EVs, which are delivered to the extracellular space. Exosomes can be released by the umbilical cord, placenta, amniotic fluid, and amniotic membranes and are involved in angiogenesis, endothelial cell migration, and embryo implantation. Also, various diseases such as gestational hypertension, gestational diabetes mellitus (GDM), preterm birth, and fetal growth restriction can be related to the content of placental exosomes during pregnancy. Due to exosomes' ability to transport signaling molecules and their effect on sperm function, they can also play a role in male and female infertility. In the new insight, exosomal miRNA can diagnose and treat infertilities disorders. In this review, we focused on the functions of exosomes during pregnancy.

Interactome analysis of human phospholipase D and phosphatidic acid-associated protein network

Mammalian phospholipase D (PLD) enzyme family consists of six members. Among them, PLD1/2/6 catalyzes phosphatidic acid (PA) production, while PLD3/4/5 has no catalytic activities. Deregulation of the PLD-PA lipid signaling has been associated with various human diseases including cancer. However, a comprehensive analysis of the regulators and effectors for this crucial lipid metabolic pathway has not been fully achieved. Using a proteomic approach, we defined the protein interaction network for the human PLD family of enzymes and PA and revealed diverse cellular signaling events involving them. Through it, we identified PJA2 as a novel E3 ubiquitin ligase for PLD1 involved in control of the PLD1-mediated mammalian target of rapamycin signaling. Additionally, we showed that PA interacted with and positively regulated sphingosine kinase 1. Taken together, our study not only generates a rich interactome resource for further characterizing the human PLD-PA lipid signaling but also connects this important metabolic pathway with numerous biological processes.

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Defining the interactome of human phospholipase D enzymes and phosphatidic acid.

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PJA2 functions as an E3 ubiquitin ligase of phospholipase D1.

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Phosphatidic acid interacts with and positively regulates sphingosine kinase 1.

Regulating the production and biological function of small extracellular vesicles: current strategies, applications and prospects

Numerous studies have confirmed the great application potentials of small extracellular vesicles (sEVs) in biological medical field, especially in tissue repair and regeneration. However, the production capability of sEVs by noncancerous cells is very limited, while their dosage requirements in disease treatments are usually very high. Meanwhile, as cell aging, the sEV production capability of cells decreases and the biological function of sEVs changes accordingly. In addition, for special applications, sEVs carrying desired bioactive substances should be designed to perform their expected biological function. Therefore, improving the production of sEVs and precisely regulating their biological function are of great significance for promoting the clinical applications of sEVs. In this review, some of the current classic strategies in affecting the cellular behaviors of donor cells and subsequently regulating the production and biological function of their sEVs are summarized, including gene engineering methods, stress-inducing conditions, chemical regulators, physical methods, and biomaterial stimulations. Through applying these strategies, increased yield of sEVs with required biological function can be obtained for disease treatment and tissue repair, such as bone regeneration, wound healing, nerve function recovery and cancer treatment, which could not only reduce the harvest cost of sEV but promote the practical applications of sEVs in clinic.

Exosomes in the Healthy and Malignant Bone Marrow Microenvironment

The bone marrow (BM) is a complex organ that sustains hematopoiesis via mechanisms involving the microenvironment. The microenvironment includes several cell types, neurotransmitters from innervated fibers, growth factors, extracellular matrix proteins, and extracellular vesicles. The main function of the BM is to regulate hematopoietic function to sustain the production of blood and immune cells. However, the BM microenvironment can also accommodate the survival of malignant cells. A major mechanism by which the cancer cells communicate with cells of the BM microenvironment is through the exchange of exosomes, a subset of extracellular vesicles that deliver molecular signals bidirectionally between malignant and healthy cells. The field of exosomes is an active area of investigation since an understanding of how the exosomal packaging, cargo, and production can be leveraged therapeutically to deter cancer progression and sensitize malignant cells to other therapies. Altogether, this chapter discusses the crucial role of exosomes in the development and progression of BM-associated cancers, such as hematologic malignancies and marrow-metastatic breast cancer. Exosome-based therapeutic strategies and their limitations are also considered.

Formation, contents, functions of exosomes and their potential in lung cancer diagnostics and therapeutics

Lung cancer is the leading cause of cancer-related death worldwide due to diagnosis in the advanced stage and drug resistance in the subsequent treatments. Development of novel diagnostic and therapeutic methods is urged to improve the disease outcome. Exosomes are nano-sized vehicles which transport different types of biomolecules intercellularly, including DNA, RNA and proteins, and are implicated in cross-talk between cells and their surrounding microenvironment. Tumor-derived exosomes (TEXs) have been revealed to strongly influence the tumor microenvironment, antitumor immunoregulatory activities, tumor progression and metastasis. Potential of TEXs as biomarkers for lung cancer diagnosis, prognosis and treatment prediction is supported by numerous studies. Moreover, exosomes have been proposed to be promising drug carriers. Here, we review the mechanisms of exosomal formation and uptake, the functions of exosomes in carcinogenesis, and potential clinical utility of exosomes as biomarkers, tumor vaccine and drug delivery vehicles in the diagnosis and therapeutics of lung cancer.

Phospholipids in small extracellular vesicles: emerging regulators of neurodegenerative diseases and cancer

Small extracellular vesicles (sEVs) are generated by almost all cell types. They have a bilayer membrane structure that is similar to cell membranes. Thus, the phospholipids contained in sEVs are the main components of cell membranes and function as structural support elements. However, as in-depth research on sEV membrane components is conducted, some phospholipids have been found to participate in cellular biological processes and function as targets for cell-cell communication. Currently, sEVs are being developed as part of drug delivery systems and diagnostic factors for various diseases, especially neurodegenerative diseases and cancer. An understanding of the physiological and pathological roles of sEV phospholipids in cellular processes is essential for their future medical application. In this review, the authors discuss phospholipid components in sEVs of different origins and summarize the roles of phospholipids in sEV biogenesis. The authors further collect the current knowledge on the functional roles of sEV phospholipids in cell-cell communication and bioactivities as signals regulating neurodegenerative diseases and cancer and the possibility of using sEV phospholipids as biomarkers or in drug delivery systems for cancer diagnosis and treatment. Knowledge of sEV phospholipids is important to help us identify directions for future studies.

Promotion or inhibition of extracellular vesicle release: Emerging therapeutic opportunities

Extracellular vesicles (EVs) are vehicles of intercellular communication that are released from various cell types under physiological and pathological conditions, with differing effects on the body. Under physiological conditions, EVs mediate cell-to-cell and intertissue communication and participate in maintaining homeostasis. Certain EV types have emerged as biological therapeutic agents in various fields, such as cell-free regenerative medicine, drug delivery and immunotherapy. However, the low yield of EVs is a bottleneck in the large-scale implementation of these therapies. Conversely, more EVs in the microenvironment in other circumstances, such as tumor metastasis, viral particle transmission, and the propagation of neurodegenerative disease, can exacerbate the situation, and the inhibition of EV secretion may delay the progression of these diseases. Therefore, the promotion and inhibition of EV release is a new and promising field because of its great research potential and wide application prospects. We first review the methods and therapeutic opportunities for the regulation of EV release based on the mechanism of EV biogenesis and consider the side effects and challenges.

What we know on the potential use of exosomes for nanodelivery

Antitumor therapy is taking into consideration the possibility to use natural nanovesicles, called exosomes, as an ideal delivery for both old and new anti-cancer molecules. This with the attempt to improve the efficacy, at the same time reducing the systemic toxicity of physical, chemical, and biological molecules. Exosomes may in fact increase the level of biomimetism, through simulating what really occurs in nature. Although extracellularly released vesicles include both microvesicles (MVs) and exosomes, only exosomes have the size that may be considered suitable for potential use to this purpose, also by analogy with the diffusely used artificial nanoparticles, such as lyposomes. In fact, recent reports have shown that exosomes are able to interact with target cells within an organ or at a distance using different mechanisms. Much is yet to be understood about exosomes, and currently, we are looking at the visible top of an iceberg, with most of what we have to understand on these nanovesicles still under the sea. In fact, we know that exosomes released by normal cells always trigger positive effects, while those released by cells in pathological condition, such as tumors may induce undesired, dangerous, and mostly unknown effects. To date we have many pre-clinical data available and possibly useful to think about a strategic use of exosomes as a delivery nanodevice in cancer treatment. However, this review wants to critically emphasize two important points actually hampering further discussion in the field : (i) the clinical data are virtually absent at the moment ; (ii) the best cellular source of exosomes to be used to deliver drugs is really far to be defined. Facing off these two points may well facilitate the attempt to figure out this very important issue for improving at the best future anti-cancer treatments.

Mini Review: Current Trends and Understanding of Exosome Therapeutic Potential in Corneal Diseases

Exosomes are a subset of extracellular vesicles (EVs) that are secreted by most cell types. They are nanosized EVs ranging from 30 to 150 nm. The membrane-enclosed bodies originate by the process of endocytosis and mainly comprise DNA, RNA, protein, and lipids. Exosomes not only act as cell-to-cell communication signaling mediators but also have the potential to act as biomarkers for clinical application and as a promising carrier for drug delivery. Unfortunately, the purification methods for exosomes remain an obstacle. While most of the exosome researches are mainly focused on cancer, there are limited studies highlighting the importance of exosomes in ocular biology, specifically cornea-associated pathologies. Here, we summarize a brief description of exosome biogenesis, roles of exosomes and exosome-based therapies in corneal pathologies, and exosome bioengineering for tissue-specific therapy.

Extracellular Vehicles of Oxygen-Depleted Mesenchymal Stromal Cells: Route to Off-Shelf Cellular Therapeutics?

Cellular therapy is a promising tool of human medicine to successfully treat complex and challenging pathologies such as cardiovascular diseases or chronic inflammatory conditions. Bone marrow-derived mesenchymal stromal cells (BMSCs) are in the limelight of these efforts, initially, trying to exploit their natural properties by direct transplantation. Extensive research on the therapeutic use of BMSCs shed light on a number of key aspects of BMSC physiology including the importance of oxygen in the control of BMSC phenotype. These efforts also led to a growing number of evidence indicating that the beneficial therapeutic effects of BMSCs can be mediated by BMSC-secreted agents. Further investigations revealed that BMSC-excreted extracellular vesicles could mediate the potentially therapeutic effects of BMSCs. Here, we review our current understanding of the relationship between low oxygen conditions and the effects of BMSC-secreted extracellular vesicles focusing on the possible medical relevance of this interplay.

Comparing the Therapeutic Potential of Stem Cells and their Secretory Products in Regenerative Medicine

Cell therapy involves the transplantation of human cells to replace or repair the damaged tissues and modulate the mechanisms underlying disease initiation and progression in the body. Nowadays, many different types of cell-based therapy are developed and used to treat a variety of diseases. In the past decade, cell-free therapy has emerged as a novel approach in regenerative medicine after the discovery that the transplanted cells exerted their therapeutic effect mainly through the secretion of paracrine factors. More and more evidence showed that stem cell-derived secretome, i.e., growth factors, cytokines, and extracellular vesicles, can repair the injured tissues as effectively as the cells. This finding has spurred a new idea to employ secretome in regenerative medicine. Despite that, will cell-free therapy slowly replace cell therapy in the future? Or are these two modes of treatment still needed to address different diseases and conditions? This review provides an indepth discussion about the values of stem cells and secretome in regenerative medicine. In addition, the safety, efficacy, advantages, and disadvantages of using these two modes of treatment in regenerative medicine are also critically reviewed.

Lipid profile of extracellular vesicles and their relationship with bovine oocyte developmental competence: New players in intra follicular cell communication

Cell communication within the ovarian follicle is crucial during folliculogenesis to assure an ideal environment for the oocyte to achieve full developmental competence. Intercellular communication is facilitated by the presence of follicular fluid, which mediates the transfer of signaling molecules. Recently, extracellular vesicles (exosomes and microvesicles) containing mRNAs, miRNAs and proteins were described in mammalian follicular fluid. Besides these molecules, extracellular vesicles (EVs) can mediate the transfer of lipids that can act as signal transducers activating second messengers and modulating intracellular pathways. Our goal was to determine the lipid profile of exosomes (small extracellular vesicles) and microvesicles (large extracellular vesicles) from bovine ovarian follicles containing oocytes with different developmental capabilities to verify potential relationships to competence. Using mass spectrometry, we examined the lipid content of EVs present in the follicular fluid of follicles enclosing oocytes that were either unable to cleave (NCLEAVE), arrested at cleavage stage (CLEAVE), or developed to the blastocyst stage (BLAST) after parthenogenetic activation. Although most of the 514 lipids identified in the follicular fluid EVs were common among all groups, 10 exosome-derived lipids and 15 microvesicle-derived lipids were present exclusively in the BLAST group, suggesting a potential relationship with developmental competence. Therefore, our data indicate that the EVs present in follicular fluid of antral follicles of similar morphology contain lipids that may be used as biomarkers associated with the developmental capability of the oocyte to develop to the blastocyst stage.

The emerging role of exosomes in Alzheimer's disease

Alzheimer's disease (AD), manifested by memory loss and a decline in cognitive functions, is the most prevalent neurodegenerative disease accounting for 60-80 % of dementia cases. But, to-date, there is no effective treatment available to slow or stop the progression of AD. Exosomes are small extracellular vesicles that carry constituents, such as functional messenger RNAs, non-coding RNAs, proteins, lipids, DNA, and other bioactive substances of their source cells. In the brain, exosomes are likely to be sourced by almost all cell types and involve in cell communication to regulate cellular functions. The yet, accumulated evidence on the roles of exosomes and their constituents in the AD pathological process suggests their significance as additional biomarkers and therapeutic targets for AD. This review summarizes the current reported research findings on exosomes roles in the pathogenesis, diagnosis, and treatment of AD.

Fatty Acid Unsaturation Degree of Plasma Exosomes in Colorectal Cancer Patients: A Promising Biomarker

Even though colorectal cancer (CRC) is one of the most preventable cancers, it is currently one of the deadliest. Worryingly, incidence in people <50 years has increased unexpectedly, and for unknown causes, despite the successful implementation of screening programs in the population aged >50 years. Thus, there is a need to improve early diagnosis detection strategies by identifying more precise biomarkers. In this scenario, the analysis of exosomes is given considerable attention. Previously, we demonstrated the exosome lipidome was able to classify CRC cell lines according to their malignancy. Herein, we investigated the use of the lipidome of plasma extracellular vesicles as a potential source of non-invasive biomarkers for CRC. A plasma exosome-enriched fraction was analyzed from patients undergoing colonoscopic procedure. Patients were divided into a healthy group and four pathological groups (patients with hyperplastic polyps; adenomatous polyps; invasive neoplasia (CRC patients); or hereditary non-polyposis CRC. The results showed a shift from 34:1- to 38:4-containing species in the pathological groups. We demonstrate that the ratio Σ34:1-containing species/Σ38:4-containing species has the potential to discriminate between healthy and pathological patients. Altogether, the results reinforce the utility of plasma exosome lipid fingerprint to provide new non-invasive biomarkers in a clinical context.

Insights Into Exosomal Non-Coding RNAs Sorting Mechanism and Clinical Application

Exosomes are natural nanoscale bilayer phospholipid vesicles that can be secreted by almost all types of cells and are detected in almost all types of body fluids. Exosomes are effective mediators of cell–cell signaling communication because of their ability to carry and transfer a variety of bioactive molecules, including non-coding RNAs. Non-coding RNAs have also been found to exert strong effects on a variety of biological processes, including tumorigenesis. Many researchers have established that exosomes encapsulate bioactive non-coding RNAs that alter the biological phenotype of specific target cells in an autocrine or a paracrine manner. However, the mechanism by which the producer cells package non-coding RNAs into exosomes is not well understood. This review focuses on the current research on exosomal non-coding RNAs, including the biogenesis of exosomes, the possible mechanism of sorting non-coding RNAs, their biological functions, and their potential for clinical application in the future.

Extracellular vesicle interplay in cardiovascular pathophysiology

Extracellular vesicles (EVs) are nanosized lipid bilayer-delimited particles released from cells that mediate intercellular communications and play a pivotal role in various physiological and pathological processes. Subtypes of EVs may include plasma membrane ectosomes or microvesicles and endosomal origin exosomes, although functional distinctions remain unclear. EVs carry cargo proteins, nucleic acids (RNA and DNA), lipids, and metabolites. By presenting or transferring this cargo to recipient cells, EVs can trigger cellular responses. We summarize contemporary understanding of EV biogenesis, composition, and function, with an emphasis on the role of EVs in the cardiovascular system. In addition, we outline the functional relevance of EVs in cardiovascular pathophysiology, further highlighting their potential for diagnostic and therapeutic applications.

Exosome-Derived Mediators as Potential Biomarkers for Cardiovascular Diseases: A Network Approach

Cardiovascular diseases (CVDs) are widely recognized as the leading cause of mortality worldwide. Despite the advances in clinical management over the past decades, the underlying pathological mechanisms remain largely unknown. Exosomes have drawn the attention of researchers for their relevance in intercellular communication under both physiological and pathological conditions. These vesicles are suggested as complementary prospective biomarkers of CVDs; however, the role of exosomes in CVDs is still not fully elucidated. Here, we performed a literature search on exosomal biogenesis, characteristics, and functions, as well as the different available exosomal isolation techniques. Moreover, aiming to give new insights into the interaction between exosomes and CVDs, network analysis on the role of exosome-derived mediators in coronary artery disease (CAD) and heart failure (HF) was also performed to incorporate the different sources of information. The upregulated exosomal miRNAs miR-133a, miR-208a, miR-1, miR-499-5p, and miR-30a were described for the early diagnosis of acute myocardial infarction, while the exosome-derived miR-192, miR-194, miR-146a, and miR-92b-5p were considered as potential biomarkers for HF development. In CAD patients, upregulated exosomal proteins, including fibrinogen beta/gamma chain, inter-alpha-trypsin inhibitor heavy chain, and alpha-1 antichymotrypsin, were assessed as putative protein biomarkers. From downregulated proteins in CAD patients, albumin, clusterin, and vitamin D-binding protein were considered relevant to assess prognosis. The Vesiclepedia database included miR-133a of exosomal origin upregulated in patients with CAD and the exosomal miR-192, miR-194, and miR-146a upregulated in patients with HF. Additionally, Vesiclepedia included 5 upregulated and 13 downregulated exosomal proteins in patients in CAD. The non-included miRNAs and proteins have not yet been identified in exosomes and can be proposed for further research. This report highlights the need for further studies focusing on the identification and validation of miRNAs and proteins of exosomal origin as biomarkers of CAD and HF, which will enable, using exosomal biomarkers, the guiding of diagnosis/prognosis in CVDs.

Proteomic Analysis of Extracellular Vesicles Derived from MDA-MB-231 Cells in Microgravity

Patients with triple-negative breast cancer (TNBC) have a relatively poor prognosis and cannot benefit from endocrine and/or targeted therapy. Considerable effort has been devoted toward the elucidation of the molecular mechanisms and potential diagnostic/therapeutic targets. However, it is inefficient and often ineffective to study the biological nuances of TNBC in large-scale clinical trials. In contrast, the investigation of the association between molecular alterations induced through controlled variables and relevant physiochemical characteristics of TNBC cells in laboratory settings is simple, definite, and efficient in exploring the molecular mechanisms. In this study, microgravity was selected as the sole variable of study as it can inhibit cancer cell viability, proliferation, metastasis, and chemoresistance. Identifying the key molecules that shift cancer cells toward a less aggressive phenotype may facilitate future TNBC studies. We focused on extracellular vesicles (EV) derived from TNBC MDA-MB-231 cells in microgravity, which mediate intercellular communication by transporting signaling molecules between cells. Our results show that in comparison with cells in full gravity, EV release rate decreased in microgravity while average EV size increased. In addition, we found EVs may be superior to cells in analyzing differentially expressed proteins, especially those that are down-regulated ones and usually unidentified or neglected in analysis of intact cellular contents. Proteomic analysis of both EVs and cells further revealed a significant correlation with GTPases and proliferation of MDA-MB-231 cells in microgravity. Altogether, our findings would further inspire in-depth correlative cancer biological studies and subsequent clinical research.

Dexosomes as a cell-free vaccine for cancer immunotherapy

Dendritic cells (DCs) secrete vast quantities of exosomes termed as dexosomes. Dexosomes are symmetric nanoscale heat-stable vesicles that consist of a lipid bilayer displaying a characteristic series of lipid and protein molecules. They include tetraspanins and all established proteins for presenting antigenic material such as the major histocompatibility complex class I/II (MHC I/II) and CD1a, b, c, d proteins and CD86 costimulatory molecule. Dexosomes contribute to antigen-specific cellular immune responses by incorporating the MHC proteins with antigen molecules and transferring the antigen-MHC complexes and other associated molecules to naïve DCs. A variety of ex vivo and in vivo studies demonstrated that antigen-loaded dexosomes were able to initiate potent antitumor immunity. Human dexosomes can be easily prepared using monocyte-derived DCs isolated by leukapheresis of peripheral blood and treated ex vivo by cytokines and other factors. The feasibility of implementing dexosomes as therapeutic antitumor vaccines has been verified in two phase I and one phase II clinical trials in malignant melanoma and non small cell lung carcinoma patients. These studies proved the safety of dexosome administration and showed that dexosome vaccines have the capacity to trigger both the adaptive (T lymphocytes) and the innate (natural killer cells) immune cell recalls. In the current review, we will focus on the perspective of utilizing dexosome vaccines in the context of cancer immunotherapy.

Emerging mechanisms contributing to mast cell-mediated pathophysiology with therapeutic implications

Mast cells are tissue-resident immune cells that play key roles in the initiation and perpetuation of allergic inflammation, usually through IgE-mediated mechanisms. Mast cells are, however, evolutionary ancient immune cells that can be traced back to urochordates and before the emergence of IgE antibodies, suggesting their involvement in antibody-independent biological functions, many of which are still being characterized. Herein, we summarize recent advances in understanding the roles of mast cells in health and disease, partly through the study of emerging non-IgE receptors such as the Mas-related G protein-coupled receptor X2, implicated in pseudo-allergic reactions as well as in innate defense and neuronal sensing; the mechano-sensing adhesion G protein-coupled receptor E2, variants of which are associated with familial vibratory urticaria; and purinergic receptors, which orchestrate tissue damage responses similarly to the IL-33 receptor. Recent evidence also points toward novel mechanisms that contribute to mast cell-mediated pathophysiology. Thus, in addition to releasing preformed mediators contained in granules and synthesizing mediators de novo, mast cells also secrete extracellular vesicles, which convey biological functions. Understanding their release, composition and uptake within a variety of clinical conditions will contribute to the understanding of disease specific pathology and likely lead the way to novel therapeutic approaches. We also discuss recent advances in the development of therapies targeting mast cell activity, including the ligation of inhibitory ITIM-containing receptors, and other strategies that suppress mast cells or responses to mediators for the management of mast cell-related diseases.

The role of exosome lipids in central nervous system diseases

Central nervous system (CNS) diseases are common diseases that threaten human health. The CNS is highly enriched in lipids, which play important roles in maintaining normal physiological functions of the nervous system. Moreover, many CNS diseases are closely associated with abnormal lipid metabolism. Exosomes are a subtype of extracellular vesicles (EVs) secreted from multivesicular bodies (MVBs) . Through novel forms of intercellular communication, exosomes secreted by brain cells can mediate inter-neuronal signaling and play important roles in the pathogenesis of CNS diseases. Lipids are essential components of exosomes, with cholesterol and sphingolipid as representative constituents of its bilayer membrane. In the CNS, lipids are closely related to the formation and function of exosomes. Their dysregulation causes abnormalities in exosomes, which may, in turn, lead to dysfunctions in inter-neuronal communication and promote diseases. Therefore, the role of lipids in the treatment of neurological diseases through exosomes has received increasing attention. The aim of this review is to discuss the relationship between lipids and exosomes and their roles in CNS diseases.

Extracellular vesicles: Roles and applications in drug-induced liver injury

Extracellular vesicles (EV) are defined as nanosized particles, with a lipid bilayer, that are unable to replicate. There has been an exponential increase of research investigating these particles in a wide array of diseases and deleterious states (inflammation, oxidative stress, drug-induced liver injury) in large part due to increasing recognition of the functional capacity of EVs. Cells can package lipids, proteins, miRNAs, DNA, and RNA into EVs and send these discrete packages of molecular information to distant, recipient cells to alter the physiological state of that cell. EVs are innately heterogeneous as a result of the diverse molecular pathways that are used to generate them. However, this innate heterogeneity of EVs is amplified due to the diversity in isolation techniques and lack of standardized nomenclature in the literature making it unclear if one scientist's "exosome" is another scientist's "microvesicle." One goal of this chapter is to provide the contextual understanding of EV origin so one can discern between divergent nomenclature. Further, the chapter will explore the potential protective and harmful roles that EVs play in DILI, and the potential of EVs and their cargo as a biomarker. The use of EVs as a therapeutic as well as a vector for therapeutic delivery will be discussed.