Focus on Extracellular Vesicles: Physiological Role and Signalling Properties of Extracellular Membrane Vesicles

Isolation of Extracellular Vesicles from Biological Fluids via the Aggregation-Precipitation Approach for Downstream miRNAs Detection

Extracellular vesicles (EVs) have high potential as sources of biomarkers for non-invasive diagnostics. Thus, a simple and productive method of EV isolation is demanded for certain scientific and medical applications of EVs. Here we aim to develop a simple and effective method of EV isolation from different biofluids, suitable for both scientific, and clinical analyses of miRNAs transported by EVs. The proposed aggregation-precipitation method is based on the aggregation of EVs using dextran blue and the subsequent precipitation of EVs using 1.5% polyethylene glycol solutions. The developed method allows the effective isolation of EVs from plasma and urine. As shown using TEM, dynamic light scattering, and miRNA analyses, this method is not inferior to ultracentrifugation-based EV isolation in terms of its efficacy, lack of inhibitors for polymerase reactions and applicable for both healthy donors and cancer patients. This method is fast, simple, does not need complicated equipment, can be adapted for different biofluids, and has a low cost. The aggregation-precipitation method of EV isolation accessible and suitable for both research and clinical laboratories. This method has the potential to increase the diagnostic and prognostic utilization of EVs and miRNA-based diagnostics of urogenital pathologies.

The role of extracellular vesicles in podocyte autophagy in kidney disease

Podocytes are the key cells involved in protein filtration in the glomerulus. Once proteins appear in the urine when podocytes fail, patients will end with renal failure due to the progression of glomerular damage if no proper treatment is applied. The injury and loss of podocytes can be attributed to diverse factors, such as genetic, immunologic, toxic, or metabolic disorders. Recently, autophagy has emerged as a key mechanism to eliminate the unwanted cytoplasmic materials and to prolong the lifespan of podocytes by alleviating cell damage and stress. Typically, the fundamental function of extracellular vesicles (EVs) is to mediate the intercellular communication. Recent studies have suggested that, EVs, especially exosomes, play a certain role in information transfer by communicating proteins, mRNAs, and microRNAs with recipient cells. Under physiological and pathological conditions, EVs assist in the bioinformation interchange between kidneys and other organs. It is suggested that EVs are related to the pathogenesis of acute kidney injury and chronic kidney disease, including glomerular disease, diabetic nephropathy, renal fibrosis and end-stage renal disease. However, the role of EVs in podocyte autophagy remains unclear so far. Here, this study integrated the existing information about the relevancy, diagnostic value and therapeutic potential of EVs in a variety of podocytes-related diseases. The accumulating evidence highlighted that autophagy played a critical role in the homeostasis of podocytes in glomerular disease.

Therapeutic application of extracellular vesicles for musculoskeletal repair & regeneration

Traumatic musculoskeletal injuries are common in both the civilian and combat care settings. Significant barriers exist to repairing these injuries including fracture nonunion, muscle fibrosis, re-innervation, and compartment syndrome, as well as infection and inflammation. Recently, extracellular vesicles (EVs), including exosomes and microvesicles, have attracted attention in the field of musculoskeletal regeneration. These vesicles are released by different cell types and play a vital role in cell communication by delivering functional cargoes such as proteins and RNAs. Many of these cargo molecules can be utilized for repair purposes in skeletal disorders such as osteoporosis, osteogenesis imperfecta, sarcopenia, and fracture healing. There are, however, some challenges to overcome in order to advance the successful application of these vesicles in the therapeutic setting. These include large-scale production and isolation of exosomes, long-term storage, in vivo stability, and strategies for tissue-specific targeting and delivery. This paper reviews the general characteristics of exosomes along with their physiological roles and contribution to the pathogenesis of musculoskeletal diseases. We also highlight new findings on the use of synthetic exosomes to overcome the limitations of native exosomes in treating musculoskeletal injuries and disorders.

Platelet-derived microvesicles induce calcium oscillations and promote VSMC migration via TRPV4

Rationale: Abnormal migration of vascular smooth muscle cells (VSMCs) from the media to the interior is a critical process during the intimal restenosis caused by vascular injury. Here, we determined the role of platelet-derived microvesicles (PMVs) released by activated platelets in VSMC migration.

Methods: A percutaneous transluminal angioplasty balloon dilatation catheter was used to establish vascular intimal injury. Collagen I was used to activate PMVs, mimicking collagen exposure during intimal injury. To determine the effects of PMVs on VSMC migration in vitro, scratch wound healing assays were performed. Fluorescence resonance energy transfer was used to detect variations of calcium dynamics in VSMCs.

Results: Morphological results showed that neointimal hyperplasia was markedly increased after balloon injury of the carotid artery in rats, and the main component was VSMCs. PMVs significantly promoted single cell migration and wound closure in vitro. Fluorescence resonance energy transfer revealed that PMVs induced temporal and dynamic calcium oscillations in the cytoplasms of VSMCs. The influx of extracellular calcium, but not calcium from intracellular stores, was involved in the process described above. The channel antagonist GSK219 and specific siRNA revealed that a membrane calcium channel, transient receptor potential vanilloid 4 (TRPV4), participated in the calcium oscillations and VSMC migration induced by PMVs.

Conclusions: TRPV4 participated in the calcium oscillations and VSMC migration induced by PMVs. PMVs and the related molecules might be novel therapeutic targets for vascular remodeling during vascular injury.

Targeting cellular senescence based on interorganelle communication, multilevel proteostasis, and metabolic control

Cellular senescence, a stable cell division arrest caused by severe damage and stress, is a hallmark of aging in vertebrates including humans. With progressing age, senescent cells accumulate in a variety of mammalian tissues, where they contribute to tissue aging, identifying cellular senescence as a major target to delay or prevent aging. There is an increasing demand for the discovery of new classes of small molecules that would either avoid or postpone cellular senescence by selectively eliminating senescent cells from the body (i.e., ‘senolytics’) or inactivating/switching damage‐inducing properties of senescent cells (i.e., ‘senostatics/senomorphics’), such as the senescence‐associated secretory phenotype. Whereas compounds with senolytic or senostatic activity have already been described, their efficacy and specificity has not been fully established for clinical use yet. Here, we review mechanisms of senescence that are related to mitochondria and their interorganelle communication, and the involvement of proteostasis networks and metabolic control in the senescent phenotype. These cellular functions are associated with cellular senescence in in vitro and in vivo models but have not been fully exploited for the search of new compounds to counteract senescence yet. Therefore, we explore possibilities to target these mechanisms as new opportunities to selectively eliminate and/or disable senescent cells with the aim of tissue rejuvenation. We assume that this research will provide new compounds from the chemical space which act as mimetics of caloric restriction, modulators of calcium signaling and mitochondrial physiology, or as proteostasis optimizers, bearing the potential to counteract cellular senescence, thereby allowing healthy aging.

Advances in the discovery of exosome inhibitors in cancer

Exosomes are small membrane vesicles released by most eukaryotic cells. They are considered to play an essential role in cell-to-cell communication, and It is also found that they serve as functional mediators in many severe diseases, including progression of various types of cancers. Inhibition of exosome release may slow the progression of some cancers; thus, exosome has been an attractive target for cancer treatment. Over the years, considerable efforts have been made to discover novel, highly potent and excellently selective exosome inhibitors. Most of these inhibitors are derived from synthetic compounds, some of which are currently existed drugs and found to have the potential to inhibit exosome release. In this review, we briefly discussed the development of exosome inhibitors that are currently discovered and provided guidance for the future development of inhibitors.

Extracellular Vesicles as Nanotherapeutics for Parkinson's Disease

Extracellular vesicles (EVs) are naturally occurring membranous structures secreted by normal and diseased cells, and carrying a wide range of bioactive molecules. In the central nervous system (CNS), EVs are important in both homeostasis and pathology. Through receptor-ligand interactions, direct fusion, or endocytosis, EVs interact with their target cells. Accumulating evidence indicates that EVs play crucial roles in the pathogenesis of many neurodegenerative disorders (NDs), including Parkinson's disease (PD). PD is the second most common ND, characterized by the progressive loss of dopaminergic (DAergic) neurons within the Substantia Nigra pars compacta (SNpc). In PD, EVs are secreted by both neurons and glial cells, with either beneficial or detrimental effects, via a complex program of cell-to-cell communication. The functions of EVs in PD range from their etiopathogenetic relevance to their use as diagnostic tools and innovative carriers of therapeutics. Because they can cross the blood-brain barrier, EVs can be engineered to deliver bioactive molecules (e.g., small interfering RNAs, catalase) within the CNS. This review summarizes the latest findings regarding the role played by EVs in PD etiology, diagnosis, prognosis, and therapy, with a particular focus on their use as novel PD nanotherapeutics.

Alcohol Increases Exosome Release from Microglia to Promote Complement C1q-Induced Cellular Death of Proopiomelanocortin Neurons in the Hypothalamus in a Rat Model of Fetal Alcohol Spectrum Disorders

Microglia, a type of CNS immune cell, have been shown to contribute to ethanol-activated neuronal death of the stress regulatory proopiomelanocortin (POMC) neuron-producing β-endorphin peptides in the hypothalamus in a postnatal rat model of fetal alcohol spectrum disorders. We determined whether the microglial extracellular vesicle exosome is involved in the ethanol-induced neuronal death of the β-endorphin neuron. Extracellular vesicles were prepared from hypothalamic tissues collected from postnatal rats (both males and females) fed daily with 2.5 mg/kg ethanol or control milk formula for 5 d or from hypothalamic microglia cells obtained from postnatal rats, grown in cultures for several days, and then challenged with ethanol or vehicle for 24 h. Nanoparticle tracking analysis and transmission electron microscopy indicated that these vesicles had the size range and shape of exosomes. Ethanol treatments increased the number and the β-endorphin neuronal killing activity of microglial exosomes both in vivo and in vitro Proteomics analyses of exosomes of cultured microglial cells identified a large number of proteins, including various complements, which were elevated following ethanol treatment. Proteomics data involving complements were reconfirmed using quantitative protein assays. Ethanol treatments also increased deposition of the complement protein C1q in β-endorphin neuronal cells in both in vitro and in vivo systems. Recombinant C1q protein increased while C1q blockers reduced ethanol-induced C3a/b, C4, and membrane attack complex/C5b9 formations; ROS production; and ultimately cellular death of β-endorphin neurons. These data suggest that the complement system involving C1q-C3-C4-membrane attack complex and ROS regulates exosome-mediated, ethanol-induced β-endorphin neuronal death.SIGNIFICANCE STATEMENT Neurotoxic action of alcohol during the developmental period is recognized for its involvement in fetal alcohol spectrum disorders, but the lack of clear understanding of the mechanism of alcohol action has delayed the progress in therapeutic intervention of this disease. Proopiomelanocortin neurons known to regulate stress, energy homeostasis, and immune functions are reported to be killed by developmental alcohol exposure because of activation of microglial immune cells in the brain. While microglia are known to use extracellular vesicles to communicate with neurons for maintaining homeostasis, we show here that ethanol exposure during the developmental period hijacks this system to spread apoptotic factors, including complement protein C1q, to induce the membrane attack complex and reactive super-oxygen species for proopiomelanocortin neuronal killing.

Rapid isolation and proteome analysis of urinary exosome based on double interactions of Fe3O4@TiO2-DNA aptamer

There are accumulating evidence that proteins carried by exosomes in urine are most possibly used as biomarkers or therapeutic carriers for certain diseases. The isolation of exosomes is therefore highly desirable for aiding the downstream protein analysis. Particularly, urine is a dynamic biological fluid changing within a short time, resulting in that the separation of urinary exosome requires more efficient technology. Here, a new biocompatible material (denoted as Fe₃O₄@TiO₂-CD63 aptamer) is designed and synthesized for rapid exosome isolation from human urine, depending on the double interactions of TiO₂ with phosphate groups as well as aptamers with specific exosome proteins. Moreover, within 10 min, 92.6% exosomes with intact structure are captured from urine by Fe₃O₄@TiO₂-CD63 aptamers, from which 999 proteins are detected through LC-MS/MS.

The involvement of exosomes in the diagnosis and treatment of pancreatic cancer

At the moment, pancreatic cancer is among the deadliest gastrointestinal diseases, and pancreatic cancer growth is a complex biological process that is based on different kinds of genes. Exosomes are extracellular vesicles containing microRNAs (miRNAs), messenger RNA (mRNA), and proteins, they act as the most prominent mediator of intercellular communication, and they regulate, instruct, and re-educate their surrounding microenvironment and target specific organs. Due to accumulative evidence proved that exosomes are involved in metastasis, cell proliferation, EMT, angiogenesis, and TME of pancreatic cancer, exosomes are crucial potential candidates to detect pancreatic cancer early. This review aims to convey the current understanding of the main functions employed by exosomes in early diagnosis and treatment of pancreatic cancer.

Extracellular Vesicle-Related Thrombosis in Viral Infection

Although the outcomes of viral infectious diseases are remarkably varied, most infections cause acute diseases after a short period. Novel coronavirus disease 2019, which recently spread worldwide, is no exception. Extracellular vesicles (EVs) are small circulating membrane-enclosed entities shed from the cell surface in response to cell activation or apoptosis. EVs transport various kinds of bioactive molecules between cells, including functional RNAs, such as viral RNAs and proteins. Therefore, when EVs are at high levels, changes in cell activation, inflammation, angioplasty and transportation suggest that EVs are associated with various diseases. Clinical research on EVs includes studies on the coagulatory system. In particular, abnormal enhancement of the coagulatory system through EVs can cause thrombosis. In this review, we address the functions of EVs, thrombosis, and their involvement in viral infection.

Cell-Free Extracellular Vesicles Derived from Human Bone Marrow Endothelial Progenitor Cells as Potential Therapeutics for Microvascular Endothelium Restoration in ALS

Repairing the damaged blood-CNS-barrier in amyotrophic lateral sclerosis (ALS) is necessary to prevent entry of detrimental blood-borne factors contributing to motor neuron dysfunction. Recently, we showed benefits of human bone marrow endothelial progenitor cell (hBM-EPC) transplantation into symptomatic ALS mice on barrier restoration by replacing damaged endothelial cells (ECs). Additionally, transplanted cells may endogenously repair ECs by secreting angiogenic factors as our subsequent in vitro study demonstrated. Based on these study results, hBM-EPCs may secrete extracellular vesicles, which may contain and transfer diverse vesicular biomolecules towards maintenance of EC functionality. The study aimed to characterize extracellular vesicles (EVs) derived from hBM-EPCs as potential cell-free therapeutics for endothelium repair in ALS. EVs were isolated from hBM-EPC media at different culture times and vesicle properties were evaluated. The protective effects of EVs on mouse brain endothelial cells (mBECs) exposed to ALS mouse plasma were investigated. Uptake and blockage of EVs from GFP-transfected hBM-EPCs in ECs were determined in vitro. Results showed that EVs isolated from hBM-EPCs as nanosized vesicles significantly reduced mBEC damage from the pathological environment and these EVs were taken up by cells. Blockage of β1 integrin on EVs prevented internalization of vesicles in mBECs. Together, these results provide evidence for potential of hBM-EPC-derived EVs as novel cell-free therapeutics for repair of endothelium in ALS. Although determining translational potential of hBM-EPC-derived EVs will require evaluation in vivo, this in vitro study represents a step towards an extracellular vesicle-based approach for repair of the damaged microvascular endothelium in ALS.

Exosomes in cancer

Exosomes are small extracellular vesicles released by cells under physiological and pathological conditions. There is emerging evidence associating exosomes with tumorigenesis. They carry cargo (DNA, RNA, miRNA and protein) pertaining to the cell of origin and play a key role in intercellular communication, influencing several cellular processes. Moreover, exosomes can be shed and found in almost all body fluids, providing a source of biomarkers for tumor diagnosis and prognosis. In addition, the use of exosomes for cancer therapeutics is another research area that is gaining attention. This book chapter aims to explore the role of exosomes in tumor biogenesis, progression and clinical applications, comprehensively compiling the research for three tumor types, namely head and neck cancer, lung cancer and glioblastoma.

Urinary exosomal miR-146a as a marker of albuminuria, activity changes and disease flares in lupus nephritis

BACKGROUND

Urinary exosomes, especially microRNAs (miRNAs) packaged within, are ideal sources of renal damage markers. We investigated the association between exosomal miR-146a, (anti-inflammatory regulator) and disease activity, proteinuria and systemic lupus erythematosus (SLE) flares over a 36-month follow-up period.

METHODS

We isolated urinary exosomes from 41 SLE patients, 27 with lupus nephritis (LN) and 20 healthy controls, and exosomal miR-146a, quantified by the real-time quantitative polymerase chain reaction (RT-qPCR), was correlated with histological features in 13 renal biopsies. We also analysed the association between the exosomal miR-146a and TRAF6 axis.

RESULTS

Exosomal miR-146a showed an inverse association with circulating C3 and C4 complement components, proteinuria, and with histological features such as chronicity index. This marker was able to identify LN with an AUC of 0.82 (p = 0.001). Basal exosomal miR-146a was associated with disease activity and proteinuria changes and was an independent marker of 36-month follow-up flares (OR 7.08, p = 0.02). Pathway analysis identified IRAK1 and TRAF6 as miR-146a target genes. Finally, in vitro experiments suggested that miR-146a exerts a protective effect through negative regulation of inflammation by suppressing IRAK1 and TRAF6.

CONCLUSIONS

Urinary exosomal miR-146a levels are correlated with lupus activity, proteinuria and histological features, discriminating patients with LN and being a good baseline marker of SLE flares. We have identified a relevant biological miR-146a-TRAF6 axis association in LN renal fibrosis progression.

miRNA Profiling of Circulating Small Extracellular Vesicles From Subarachnoid Hemorrhage Rats Using Next-Generation Sequencing

Background

Extracellular vesicles (EVs) are produced during abnormal and normal physiological conditions. Understanding the expression profile of microRNA (miRNA) in plasma-derived small extracellular vesicles (sEVs) and their roles in subarachnoid hemorrhage (SAH) that cause cerebral vasospasm (CVS) is imperative.

Methods

Sprague Dawley rats (250–300 g) were allocated to sham or SAH groups established using endovascular perforation method. miRNA expression profiles of plasma sEVs in both groups (each n = 4) were evaluated using next-generation sequencing (NGS).

Results

There were 142 microRNAs (miRNAs) significantly expressed differently between the two groups, of which 73 were up-regulated while 69 were down-regulated in SAH sEVs compared with those of sham (p < 0.05; fold change ≥ 2). The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analyses of differently expressed (DE) miRNAs revealed signaling pathways and target genes (TGs) in the SAH group. rno-miR-185-5p, rno-miR-103-3p, rno-miR-15b-3p, rno-miR-93-5p, and rno-miR-98-5p were the top five most up-regulated sEVs miRNAs.

Conclusion

Our results suggest that miRNA can be selectively packaged into sEVs under SAH, and this could help develop potential targets for the prevention, diagnosis, and treatment of CVS after this condition.

The characterization of extracellular vesicles-derived microRNAs in Thai malaria patients

Background

Extracellular vesicles (EVs) have been broadly studied in malaria for nearly a decade. These vesicles carry various functional biomolecules including RNA families such as microRNAs (miRNA). These EVs-derived microRNAs have numerous roles in host-parasite interactions and are considered promising biomarkers for disease severity. However, this field lacks clinical studies of malaria-infected samples. In this study, EV specific miRNAs were isolated from the plasma of patients from Thailand infected with Plasmodium vivax and Plasmodium falciparum. In addition, it is postulated that these miRNAs were differentially expressed in these groups of patients and had a role in disease onset through the regulation of specific target genes.

Methods

EVs were purified from the plasma of Thai P. vivax-infected patients (n = 19), P. falciparum-infected patients (n = 18) and uninfected individuals (n = 20). EV-derived miRNAs were then prepared and abundance of hsa-miR-15b-5p, hsa-miR-16-5p, hsa-let-7a-5p and hsa-miR-150-5p was assessed in these samples. Quantitative polymerase chain reaction was performed, and relative expression of each miRNA was calculated using hsa-miR-451a as endogenous control. Then, the targets of up-regulated miRNAs and relevant pathways were predicted by using bioinformatics. Receiver Operating Characteristic with Area under the Curve (AUC) was then calculated to assess their diagnostic potential.

Results

The relative expression of hsa-miR-150-5p and hsa-miR-15b-5p was higher in P. vivax-infected patients compared to uninfected individuals, but hsa-let-7a-5p was up-regulated in both P. vivax-infected patients and P. falciparum-infected patients. Bioinformatic analysis revealed that these miRNAs might regulate genes involved in the malaria pathway including the adherens junction and the transforming growth factor-β pathways. All up-regulated miRNAs could potentially be used as disease biomarkers as determined by AUC; however, the sensitivity and specificity require further investigation.

Conclusion

An upregulation of hsa-miR-150-5p and hsa-miR-15b-5p was observed in P. vivax-infected patients while hsa-let-7a-5p was up-regulated in both P. vivax-infected and P. falciparum-infected patients. These findings will require further validation in larger cohort groups of malaria patients to fully understand the contribution of these EVs miRNAs to malaria detection and biology.

HDAC inhibitors tune miRNAs in extracellular vesicles of dystrophic muscle-resident mesenchymal cells

We show that extracellular vesicles (EVs) released by mesenchymal cells (i.e., fibro-adipogenic progenitors-FAPs) mediate microRNA (miR) transfer to muscle stem cells (MuSCs) and that exposure of dystrophic FAPs to HDAC inhibitors (HDACis) increases the intra-EV levels of a subset of miRs, which cooperatively target biological processes of therapeutic interest, including regeneration, fibrosis, and inflammation. Increased levels of miR-206 in EVs released by FAPs of muscles from Duchenne muscular dystrophy (DMD) patients or mdx mice exposed to HDACi are associated with enhanced regeneration and decreased fibrosis. Consistently, EVs from HDACi-treated dystrophic FAPs can stimulate MuSC activation and expansion ex vivo, and promote regeneration, while inhibiting fibrosis and inflammation of dystrophic muscles, upon intramuscular transplantation in mdx mice, in vivo. AntagomiR-mediated blockade of individual miRs reveals a specific requirement of miR-206 for EV-induced expansion of MuSCs and regeneration of dystrophic muscles, and indicates that cooperative activity of HDACi-induced miRs accounts for the net biological effect of these EVs. These data point to pharmacological modulation of EV content as novel strategy for therapeutic interventions in muscular dystrophies.

Damage-associated molecular patterns in trauma

In 1994, the "danger model" argued that adaptive immune responses are driven rather by molecules released upon tissue damage than by the recognition of "strange" molecules. Thus, an alternative to the "self versus non-self recognition model" has been provided. The model, which suggests that the immune system discriminates dangerous from safe molecules, has established the basis for the future designation of damage-associated molecular patterns (DAMPs), a term that was coined by Walter G. Land, Seong, and Matzinger. The pathological importance of DAMPs is barely somewhere else evident as in the posttraumatic or post-surgical inflammation and regeneration. Since DAMPs have been identified to trigger specific immune responses and inflammation, which is not necessarily detrimental but also regenerative, it still remains difficult to describe their "friend or foe" role in the posttraumatic immunogenicity and healing process. DAMPs can be used as biomarkers to indicate and/or to monitor a disease or injury severity, but they also may serve as clinically applicable parameters for optimized indication of the timing for, i.e., secondary surgeries. While experimental studies allow the detection of these biomarkers on different levels including cellular, tissue, and circulatory milieu, this is not always easily transferable to the human situation. Thus, in this review, we focus on the recent literature dealing with the pathophysiological importance of DAMPs after traumatic injury. Since dysregulated inflammation in traumatized patients always implies disturbed resolution of inflammation, so-called model of suppressing/inhibiting inducible DAMPs (SAMPs) will be very briefly introduced. Thus, an update on this topic in the field of trauma will be provided.

Selectively-Packaged Proteins in Breast Cancer Extracellular Vesicles Involved in Metastasis

Cancer-derived extracellular vesicles are known to play a role in the progression of the disease. In this rapidly-growing field, there are many reports of phenotypic changes in cells following exposure to cancer-derived extracellular vesicles. This study examines the protein contents of vesicles derived from three well-known breast cancer cell lines, MCF-7, MDA-MB-231 and T47D, using peptide-centric LC-MS/MS and cytokine multiplex immunoassay analysis to understand the molecular basis of these changes. Through these techniques a large number of proteins within these vesicles were identified. A large proportion of these proteins are known to be important in cancer formation and progression and associated with cancer signaling, angiogenesis, metastasis and invasion and immune regulation. This highlights the importance of extracellular vesicles (EVs) in cancer communications and shows some of the mechanisms the vesicles use to assist in cancer progression.

Extracellular signaling in Dictyostelium

In the last few decades, we have learned a considerable amount about how eukaryotic cells communicate with each other, and what it is the cells are telling each other. The simplicity of Dictyostelium discoideum, and the wide variety of available tools to study this organism, makes it the equivalent of a hydrogen atom for cell and developmental biology. Studies using Dictyostelium have pioneered a good deal of our understanding of eukaryotic cell communication. In this review, we will present a brief overview of how Dictyostelium cells use extracellular signals to attract each other, repel each other, sense their local cell density, sense whether the nearby cells are starving or stressed, count themselves to organize the formation of structures containing a regulated number of cells, sense the volume they are in, and organize their multicellular development. Although we are probably just beginning to learn what the cells are telling each other, the elucidation of Dictyostelium extracellular signals has already led to the development of possible therapeutics for human diseases.

Glia-Derived Extracellular Vesicles in Parkinson's Disease

Glial cells are fundamental players in the central nervous system (CNS) development and homeostasis, both in health and disease states. In Parkinson’s disease (PD), a dysfunctional glia-neuron crosstalk represents a common final pathway contributing to the chronic and progressive death of dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNpc). Notably, glial cells communicating with each other by an array of molecules, can acquire a “beneficial” or “destructive” phenotype, thereby enhancing neuronal death/vulnerability and/or exerting critical neuroprotective and neuroreparative functions, with mechanisms that are actively investigated. An important way of delivering messenger molecules within this glia-neuron cross-talk consists in the secretion of extracellular vesicles (EVs). EVs are nano-sized membranous particles able to convey a wide range of molecular cargoes in a controlled way, depending on the specific donor cell and the microenvironmental milieu. Given the dual role of glia in PD, glia-derived EVs may deliver molecules carrying various messages for the vulnerable/dysfunctional DAergic neurons. Here, we summarize the state-of-the-art of glial-neuron interactions and glia-derived EVs in PD. Also, EVs have the ability to cross the blood brain barrier (BBB), thus acting both within the CNS and outside, in the periphery. In these regards, this review discloses the emerging applications of EVs, with a special focus on glia-derived EVs as potential carriers of new biomarkers and nanotherapeutics for PD.

Exosomes: Carriers of Pro-Fibrotic Signals and Therapeutic Targets in Fibrosis

Exosomes are nano-sized extracellular vesicles that are released by a variety of cells. Exosomes contain cargo from cells they derived, including lipids, proteins and nucleic acids. The bilayer lipid membrane structure of exosomes protects these contents from degradation, allowing them for intercellular communication. The role of exosomes in fibrotic diseases is increasingly being valued. Exosomes, as carriers of profibrotic signals, are involved in the development of fibrotic diseases, and also regulate fibrosis by transmitting signals that inhibit fibrosis or inflammation. Exosomes mobilize and activate a range of effector cells by targeted delivery of bioactive information. Exosomes can also reflect the condition of cells, tissues and organisms, and thus become potential biomarkers of fibrotic diseases. Exosomes from bone marrow stem cells support biological signaling that regulates and inhibits fibrosis and thus initially used in the treatment of fibrotic diseases. This article briefly summarizes the role of exosomes in the pathogenesis and treatment of fibrotic diseases and raises some issues that remain to be resolved.

microRNA in Extracellular Vesicles Released by Damaged Podocytes Promote Apoptosis of Renal Tubular Epithelial Cells

Tubular injury and fibrosis are associated with progressive kidney dysfunction in advanced glomerular disease. Glomerulotubular crosstalk is thought to contribute to tubular injury. microRNAs (miRNAs) in extracellular vesicles (EVs) can modulate distant cells. We hypothesized that miRNAs in EVs derived from injured podocytes lead to tubular epithelial cell damage. As proof of this concept, tubular epithelial (HK2) cells were cultured with exosomes from puromycin-treated or healthy human podocytes, and damage was assessed. Sequencing analysis revealed the miRNA repertoire of podocyte EVs. RNA sequencing identified 63 upregulated miRNAs in EVs from puromycin-treated podocytes. Among them, five miRNAs (miR-149, -424, -542, -582, and -874) were selected as candidates for inducing tubular apoptosis according to a literature-based search. To validate the effect of the miRNAs, HK2 cells were treated with miRNA mimics. EVs from injured podocytes induced apoptosis and p38 phosphorylation of HK2 cells. The miRNA-424 and 149 mimics led to apoptosis of HK2 cells. These results show that miRNAs in EVs from injured podocytes lead to damage to tubular epithelial cells, which may contribute to the development of tubular injury in glomerular disease.

Brain Derived Exosomes Are a Double-Edged Sword in Alzheimer's Disease

Brain derived exosomes (BDEs) are extracellular nanovesicles that are collectively released by all cell lineages of the central nervous system and contain cargo from their original cells. They are emerging as key mediators of communication and waste management among neurons, glial cells and connective tissue during both physiological and pathological conditions in the brain. We review the rapidly growing frontier of BDEs biology in recent years including the involvement of exosomes in neuronal development, maintenance and communication through their multiple signaling functions. Particularly, we highlight the important role of exosomes in Alzheimer's disease (AD), both as a pathogenic agent and as a disease biomarker. Our understanding of such unique nanovesicles may offer not only answers about the (patho) physiological course in AD and associated neurodegenerative diseases but also ideal methods to develop these vesicles as vehicles for drug delivery or as tools to monitor brain diseases in a non-invasive manner because crossing the blood brain barrier is an inherent capability of exosomes. BDEs have potential as biomarkers and as therapeutic tools for AD and related brain disorders in the near future.

Exosomal proteome from the serum, bone marrow, and palm and toe pustular skin tissues of a single patient with SAPHO syndrome

Exosome proteomic analysis may reveal differentially abundant proteins that are of significance for clarifying the pathogenesis of SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis and Osteitis) syndrome. Exosomes were isolated from the serum, bone marrow and skin tissue of the palm and toe pustular areas in a unique patient with SAPHO syndrome. The exosomes were not different from those of healthy subjects in size (114.1 ± 73.7 nm) or morphology. Label-free exosome proteomic analysis identified 198 more abundant proteins and 183 less abundant compared with those of healthy subjects. Gene ontology enrichment analysis revealed that these proteins were involved in binding with a variety of biological molecules and participated in biological processes related to autoimmunity or inflammation. A total of 243 KEGG (Kyoto Encyclopedia of Gene and Genomes) pathways were enriched, of which 43 were related to immune function. It was speculated that five differentially abundant proteins, Mitogen-activated protein kinase 1 (MAPK1/MK01), Tyrosine protein kinase (SYK), Integrin beta-3 (ITB3), Serine/threonine-protein phosphatase 2a catalytic subunit alpha isoform (PP2AA) and Serine/threonine-protein phosphatase 2a 65 kDa regulatory subunit A beta isoform (2AAB), associated with multiple KEGG pathways, forms an interaction network that may be involved in the occurrence, development and prognosis of SAPHO syndrome. SIGNIFICANCE: Exosomes of SAPHO syndrome patient were not significantly different from those of healthy subjects in size and morphology. Label-free proteomic analysis of exosomal proteins in patient with SAPHO syndrome speculated 5 proteins MAPK1, SYK, ITB3, PP2AA and 2AAB, which may be involved in the occurrence, development and prognosis of SAPHO syndrome by binding with other biological molecules. It is speculated for the first time that proteins Histone H2A type 1-J and Histone H4 were related to SAPHO syndrome. Clinic relevance. Exosome proteomics can suggest novel pathological data in patients with SAPHO.

Bioinspired exosome-like therapeutics and delivery nanoplatforms

Exosomes have emerged as appealing candidate therapeutic agents and delivery nanoplatforms due to their endogenous features and unique biological properties. However, obstacles such as low isolation yield, considerable complexity and potential safety concerns, and inefficient drug payload substantially hamper their therapeutic applicability. To this end, developing bioinspired exosome-like nanoparticles has become a promising area to overcome certain limitations of their natural counterparts. Synthetically fabrication of exosome-like nanoparticles that harbor only crucial components of exosomes through controllable protocols strongly increases the pharmaceutical acceptability of these vesicles. Assembly of exosome-like nanovesicles derived from producer cells allows for a promising strategy for scale-up production. To improve the loading capability and delivery efficiency of exosomes, hybrid exosome-like nanovesicles and membrane-camouflaged nanoparticles towards better bridging synthetic nanocarriers with natural exosomes could be designed. Building off these observations, herein, efforts are made to give an overview of bioinspired exosome-like therapeutics and delivery nanoplatforms. We briefly recapitulate the recent advance in exosome biology with focus on tailoring exosomes as therapeutics and delivery vehicles. Furthermore, we elaborately discuss the biomimicry methodologies for preparation of exosome-like nanoparticles with special emphasis on offering insights into strategies for rational design of exosome-like biomaterials as effective and safe therapeutics and delivery nanoplatforms.

Extracellular acidity and increased exosome release as key phenotypes of malignant tumors

The tumor milieu is characteristically acidic as a consequence of the fermentative metabolism of glucose that results in massive accumulation of lactic acid within the cytoplasm. Tumor cells get rid of excessive protons through exchangers that are responsible for the extracellular acidification that selects cellular clones that are more apt at surviving in this challenging and culling environment. Extracellular vesicles (EVs) are vesicles with diameters ranging from nm to μm that are released from the cells to deliver nucleic acids, proteins, and lipids to adjacent or distant cells. EVs are involved in a plethora of biological events that promote tumor progression including unrestricted proliferation, angiogenesis, migration, local invasion, preparation of the metastatic niche, metastasis, downregulation or hijacking of the immune system, and drug resistance. There is evidence that the release of specific exosomes is increased many folds in cancer patients, as shown by many techniques aimed at evaluating "liquid biopsies". The quality of the exosomal contents has been shown to vary at the different moments of tumor life such as local invasion or metastasis. In vitro studies have recently pointed out that cancer acidity is a major determinant in inducing increased exosome release by human cancer cells, by showing that exosomal release was increased as the pH moved from 7.4 pH to the typical pH of cancer that is 6.5. In this review, we emphasize the recent evidence that tumor acidity and exosomes levels are strictly related and strongly contribute to the malignant tumor phenotypes.

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.

Current Knowledge and Future Perspectives on Mesenchymal Stem Cell-Derived Exosomes as a New Therapeutic Agent

Mesenchymal stem cells (MSCs) are on the cusp of regenerative medicine due to their differentiation capacity, favorable culture conditions, ability to be manipulated in vitro, and strong immunomodulatory activity. Recent studies indicate that the pleiotropic effects of MSCs, especially their immunomodulatory potential, can be largely attributed to paracrine factors. Exosomes, vesicles that are 30-150 nanometers in diameter that function in cell-cell communication, are one of the key paracrine effectors. MSC-derived exosomes are enriched with therapeutic miRNAs, mRNAs, cytokines, lipids, and growth factors. Emerging evidences support the compelling possibility of using MSC-derived exosomes as a new form of therapy for treating several different kinds of disease such as heart, kidney, immune diseases, neural injuries, and neurodegenerative disease. This review provides a summary of current knowledge and discusses engineering of MSC-derived exosomes for their use in translational medicine.

Participation of Extracellular Vesicles from Zika-Virus-Infected Mosquito Cells in the Modification of Naïve Cells' Behavior by Mediating Cell-to-Cell Transmission of Viral Elements

To date, no safe vaccine or antivirals for Zika virus (ZIKV) infection have been found. The pathogenesis of severe Zika, where host and viral factors participate, remains unclear. For the control of Zika, it is important to understand how ZIKV interacts with different host cells. Knowledge of the targeted cellular pathways which allow ZIKV to productively replicate and/or establish prolonged viral persistence contributes to novel vaccines and therapies. Monocytes and endothelial vascular cells are the main ZIKV targets. During the infection process, cells are capable of releasing extracellular vesicles (EVs). EVs are mediators of intercellular communication. We found that mosquito EVs released from ZIKV-infected (C6/36) cells carry viral RNA and ZIKV-E protein and are able to infect and activate naïve mosquito and mammalian cells. ZIKV C6/36 EVs promote the differentiation of naïve monocytes and induce a pro-inflammatory state with tumor necrosis factor-alpha (TNF-α) mRNA expression. ZIKV C6/36 EVs participate in endothelial vascular cell damage by inducing coagulation (TF) and inflammation (PAR-1) receptors at the endothelial surface of the cell membranes and promote a pro-inflammatory state with increased endothelial permeability. These data suggest that ZIKV C6/36 EVs may contribute to the pathogenesis of ZIKV infection in human hosts.

Extracellular Vesicles from Mesenchymal Stem Cells Exert Pleiotropic Effects on Amyloid-β, Inflammation, and Regeneration: A Spark of Hope for Alzheimer's Disease from Tiny Structures?

No cure yet exists for devastating Alzheimer's disease (AD), despite many years and humongous efforts to find efficacious pharmacological treatments. So far, neither designing drugs to disaggregate amyloid plaques nor tackling solely inflammation turned out to be decisive. Mesenchymal stem cells (MSCs) and, in particular, extracellular vesicles (EVs) originating from them could be proposed as an alternative, strategic approach to attack the pathology. Indeed, MSC-EVs-owing to their ability to deliver lipids/proteins/enzymes/microRNAs endowed with anti-inflammatory, amyloid-β degrading, and neurotrophic activities-may be exploited as therapeutic tools to restore synaptic function, prevent neuronal death, and slow down memory impairment in AD. Herein the results presented in the most recently published studies on this topic are critically evaluated, providing a strong rationale for possible employment of MSC-EVs in AD. Also see the video abstract here https://youtu.be/tBtDbnlRUhg.

On the Road to Accurate Biomarkers for Cardiometabolic Diseases by Integrating Precision and Gender Medicine Approaches

The need to facilitate the complex management of cardiometabolic diseases (CMD) has led to the detection of many biomarkers, however, there are no clear explanations of their role in the prevention, diagnosis or prognosis of these diseases. Molecules associated with disease pathways represent valid disease surrogates and well-fitted CMD biomarkers. To address this challenge, data from multi-omics types (genomics, epigenomics, transcriptomics, proteomics, metabolomics, microbiomics, and nutrigenomics), from human and animal models, have become available. However, individual omics types only provide data on a small part of molecules involved in the complex CMD mechanisms, whereas, here, we propose that their integration leads to multidimensional data. Such data provide a better understanding of molecules related to CMD mechanisms and, consequently, increase the possibility of identifying well-fitted biomarkers. In addition, the application of gender medicine also helps to identify accurate biomarkers according to gender, facilitating a differential CMD management. Accordingly, the impact of gender differences in CMD pathophysiology has been widely demonstrated, where gender is referred to the complex interrelation and integration of sex (as a biological and functional marker of the human body) and psychological and cultural behavior (due to ethnical, social, and religious background). In this review, all these aspects are described and discussed, as well as potential limitations and future directions in this incipient field.

Exosomal miRNA: Small Molecules, Big Impact in Colorectal Cancer

Colorectal cancer (CRC) is one of the major causes of cancer-related deaths worldwide. Tumor microenvironment (TME) contains many cell types including stromal cells, immune cells, and endothelial cells. The TME modulation explains the heterogeneity of response to therapy observed in patients. In this context, exosomes are emerging as major contributors in cancer biology. Indeed, exosomes are implicated in tumor proliferation, angiogenesis, invasion, and premetastatic niche formation. They contain bioactive molecules such as proteins, lipids, and RNAs. More recently, many studies on exosomes have focused on miRNAs, small noncoding RNA molecules able to influence protein expression. In this review, we describe miRNAs transported by exosomes in the context of CRC and discuss their influence on TME and their potential as circulating biomarkers. This overview underlines emerging roles for exosomal miRNAs in cancer research for the near future.

Methylglyoxal and Glyoxal as Potential Peripheral Markers for MCI Diagnosis and Their Effects on the Expression of Neurotrophic, Inflammatory and Neurodegenerative Factors in Neurons and in Neuronal Derived-Extracellular Vesicles

Methylglyoxal (MG) and glyoxal (GO) are suggested to be associated with the development of neurodegenerative pathologies. However, their peripheral levels in relation to cognitive decline and their effects on key factors in neuronal cells are poorly investigated. The aim of this study was to determine their serum levels in MCI (mild cognitive impairment) and Alzheimer’s disease (AD) patients, to analyze their effects on the neurotrophic and inflammatory factors, on neurodegenerative markers in neuronal cells and in neuronal derived-extracellular vesicles (nEVs). Our results show that MG and GO levels in serum, determined by HPLC, were higher in MCI. ROC (receiver-operating characteristic curves) analysis showed that the levels of MG in serum have higher sensitivity to differentiate MCI from controls but not from AD. Meanwhile, serum GO levels differentiate MCI from control and AD groups. Cells and nEVs levels of BDNF, PRGN, NSE, APP, MMP-9, ANGPTL-4, LCN2, PTX2, S100B, RAGE, Aβ peptide, pTau T181 and alpha-synuclein were quantified by luminex assay. Treatment of neuronal cells with MG or GO reduced the cellular levels of NSE, PRGN, APP, MMP-9 and ANGPTL-4 and the nEVs levels of BDNF, PRGN and LCN2. Our findings suggest that targeting MG and GO may be a promising therapeutic strategy to prevent or delay the progression of AD.

Physical Activity and Brain Health

Physical activity (PA) has been central in the life of our species for most of its history, and thus shaped our physiology during evolution. However, only recently the health consequences of a sedentary lifestyle, and of highly energetic diets, are becoming clear. It has been also acknowledged that lifestyle and diet can induce epigenetic modifications which modify chromatin structure and gene expression, thus causing even heritable metabolic outcomes. Many studies have shown that PA can reverse at least some of the unwanted effects of sedentary lifestyle, and can also contribute in delaying brain aging and degenerative pathologies such as Alzheimer’s Disease, diabetes, and multiple sclerosis. Most importantly, PA improves cognitive processes and memory, has analgesic and antidepressant effects, and even induces a sense of wellbeing, giving strength to the ancient principle of “mens sana in corpore sano” (i.e., a sound mind in a sound body). In this review we will discuss the potential mechanisms underlying the effects of PA on brain health, focusing on hormones, neurotrophins, and neurotransmitters, the release of which is modulated by PA, as well as on the intra- and extra-cellular pathways that regulate the expression of some of the genes involved.

Strategies for the use of Extracellular Vesicles for the Delivery of Therapeutics

Extracellular vesicles (EVs) are nanosized, membrane-bound vesicles released from eukaryotic and prokaryotic cells that can transport cargo containing DNA, RNA, lipids and proteins, between cells as a means of intercellular communication. Although EVs were initially considered to be cellular debris deprived of any essential biological functions, emerging literature highlights the critical roles of EVs in the context of intercellular signaling, maintenance of tissue homeostasis, modulation of immune responses, inflammation, cancer progression, angiogenesis, and coagulation under both physiological and pathological states. Based on the ability of EVs to shuttle proteins, lipids, carbohydrates, mRNAs, long non-coding RNAs (lncRNAs), microRNAs, chromosomal DNA, and mitochondrial DNA into target cells, the presence and content of EVs in biofluids have been exploited for biomarker research in the context of diagnosis, prognosis and treatment strategies. Additionally, owing to the characteristics of EVs such as stability in circulation, biocompatibility as well as low immunogenicity and toxicity, these vesicles have become attractive systems for the delivery of therapeutics. More recently, EVs are increasingly being exploited as conduits for delivery of therapeutics for anticancer strategies, immunomodulation, targeted drug delivery, tissue regeneration, and vaccination. In this review, we highlight and discuss the multiple strategies that are employed for the use of EVs as delivery vehicles for therapeutic agents, including the potential advantages and challenges involved. Graphical abstract.

Nanoformulation properties, characterization, and behavior in complex biological matrices: Challenges and opportunities for brain-targeted drug delivery applications and enhanced translational potential

Nanocarriers (synthetic/cell-based have attracted enormous interest for various therapeutic indications, including neurodegenerative disorders. A broader understanding of the impact of nanomedicines design is now required to enhance their translational potential. Nanoformulations in vivo journey is significantly affected by their physicochemical properties including the size, shape, hydrophobicity, elasticity, and surface charge/chemistry/morphology, which play a role as an interface with the biological environment. Understanding protein corona formation is crucial in characterizing nanocarriers and evaluating their interactions with biological systems. In this review, the types and properties of the brain-targeted nanocarriers are discussed. The biological factors and nanocarriers properties affecting their in vivo behavior are elaborated. The compositional description of cell culture and biological matrices, including proteins potentially relevant to protein corona built-up on nanoformulation especially for brain administration, is provided. Analytical techniques of characterizing nanocarriers in complex matrices, their advantages, limitations, and implementation challenges in industrial GMP environment are discussed. The uses of orthogonal complementary characterization approaches of nanocarriers are also covered.

Proteomic and histopathological characterisation of sicca subjects and primary Sjögren's syndrome patients reveals promising tear, saliva and extracellular vesicle disease biomarkers

Background

Mononuclear cell infiltration of exocrine glands, production of Ro/SSA and La/SSB autoantibodies, along with oral and ocular dryness, are characteristic features of primary Sjögren’s syndrome (pSS). Non-SS sicca subjects, an underexplored group in relation to pSS, display similar sicca symptoms, with possible mild signs of inflammation in their salivary glands, yet with no serological detection of autoantibody production. In this study, we investigated inflammatory manifestations in the salivary gland tissue, tear fluid and saliva of non-SS subjects, as compared to pSS patients and healthy individuals.

Methods

Fifteen non-SS, 10 pSS and 10 healthy subjects were included in the analyses. Histological evaluation of salivary gland biopsies was performed. Liquid chromatography-mass spectrometry (LC-MS) was conducted on tear fluid and stimulated whole saliva, and proteomic biomarker profiles were generated. Extracellular vesicle (EVs) isolation and characterisation from both fluids were also combined with LC-MS. The LC-MS data were analysed for quantitative differences between patient and control groups using Scaffold. Database for Annotation, Visualization and Integrated Discovery (DAVID) and Functional Enrichment Analysis Tool (FunRich) were applied for functional analyses.

Results

Histopathological evaluation of salivary gland biopsies showed implications of milder inflammation in non-SS subjects through mononuclear cell infiltration, fibrosis and fatty replacement, as compared to pSS patients. Although unaffected in the non-SS group, upregulation of proinflammatory pathways and proteins involved in ubiquitination (LMO7 and HUWE1) and B cell differentiation (TPD52) were detected in tear fluid of pSS patients. Moreover, overexpression of proteins STOM, ANXA4 and ANXA1, regulating cellular innate and adaptive immunological pathways, were further identified in EVs from tear fluid of pSS patients. Finally, whole saliva and EVs isolated from whole saliva of pSS patients expressed proteins vital for innate MHC class I cellular regulation (NGAL) and T cell activation (CD44).

Conclusions

Non-SS sicca subjects may show implications of mild inflammation in their glandular tissue, while their protein profile was strikingly more similar to healthy controls than to pSS patients. Hence, the tear and salivary biomarkers identified could be implemented as potential non-invasive diagnostic tools that may aid in increasing diagnostic accuracy when evaluating non-SS subjects and pSS patients and monitoring disease progression.

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1961-4) contains supplementary material, which is available to authorized users.

Exosomes Derived From Septic Mouse Serum Modulate Immune Responses via Exosome-Associated Cytokines

Sepsis is a life-threatening condition caused by an immune response triggered by infection, and highly elevated cytokine/chemokine levels in the blood play crucial roles in the progression of sepsis. Serum exosomes are nanovesicles that have multiple biological functions, playing roles in antigen presentation, intercellular signal communication, inflammatory response and immune surveillance. However, the biological functions and related molecular bases remain to be elucidated. In this study, we investigated the profiles of cytokines/chemokines harbored in the exosomes of septic mice and explored the mechanisms of immunomodulation on T cells treated with exosomes harvested from septic mice. Blood cytokines/chemokines existed in both the soluble form and in the insoluble exosomal form; the profiles of the cytokines/chemokines in these two forms displayed different dynamics in the blood of mice challenged with LPS. Exosomes from septic mice induced the differentiation of Th1/Th2 cells, which was blocked by specific antibodies targeting IL-12 and IL-4. In addition, these exosomes significantly augmented the proliferation and migration of T lymphocytes. Furthermore, preadministration of exosomes by intravenous injection restrained the inflammatory response, attenuated lung and liver tissue damage, and prolonged the survival of cecal ligation and puncture (CLP) mice. Our results indicate that exosomes enriched with cytokines/chemokines play critical roles in T cell differentiation, proliferation and chemotaxis during the sepsis process and have a protective effect on cecal ligation and puncture (CLP) mice. Thus, these findings not only strengthen our understanding of the role of sepsis via exosomes but also provide potential targets for therapeutic applications.

Aphidius ervi Teratocytes Release Enolase and Fatty Acid Binding Protein Through Exosomal Vesicles

The molecular bases of the host-parasitoid interactions in the biological system Acyrthosiphon pisum (Harris) (Homoptera, Aphididae) and Aphidius ervi (Haliday) (Hymenoptera, Braconidae) have been elucidated allowing the identification of a gamma-glutamyl transpeptidase, the active component of maternal venom secretion, and teratocytes, the embryonic parasitic factors responsible for host physiology regulation after parasitization. Teratocytes, cells deriving from the dissociation of the serosa, the parasitoid embryonic membrane, are responsible for extra-oral digestion of host tissues in order to provide a suitable nutritional environment for the development of parasitoid larvae. Teratocytes rapidly grow in size without undergoing any cell division, synthesize, and release in the host hemolymph two proteins: a fatty acid binding protein (Ae-FABP) and an enolase (Ae-ENO). Ae-FABP is involved in transport of fatty acids deriving from host tissues to the parasitoid larva. Ae-ENO is an extracellular glycolytic enzyme that functions as a plasminogen like receptor inducing its activation to plasmin. Both Ae-FABP and Ae-ENO lack their signal peptides, and they are released in the extracellular environment through an unknown secretion pathway. Here, we investigated the unconventional mechanism by which teratocytes release Ae-FABP and Ae-ENO in the extracellular space. Our results, obtained using immunogold staining coupled with TEM and western blot analyses, show that these two proteins are localized in vesicles released by teratocytes. The specific dimension of these vesicles and the immunodetection of ALIX and HSP70, two exosome markers, strongly support the hypothesis that these vesicles are exosomes.

Extracellular Vesicles in Human Skin: Cross-Talk from Senescent Fibroblasts to Keratinocytes by miRNAs

Extracellular vesicles (EVs) and their miRNA cargo are intercellular communicators transmitting their pleiotropic messages between different cell types, tissues, and body fluids. Recently, they have been reported to contribute to skin homeostasis and were identified as members of the senescence-associated secretory phenotype of human dermal fibroblasts. However, the role of EV-miRNAs in paracrine signaling during skin aging is yet unclear. Here we provide evidence for the existence of small EVs in the human skin and dermal interstitial fluid using dermal open flow microperfusion and show that EVs and miRNAs are transferred from dermal fibroblasts to epidermal keratinocytes in 2D cell culture and in human skin equivalents. We further show that the transient presence of senescent fibroblast derived small EVs accelerates scratch closure of epidermal keratinocytes, whereas long-term incubation impairs keratinocyte differentiation in vitro. Finally, we identify vesicular miR-23a-3p, highly secreted by senescent fibroblasts, as one contributor of the EV-mediated effect on keratinocytes in in vitro wound healing assays. To summarize, our findings support the current view that EVs and their miRNA cargo are members of the senescence-associated secretory phenotype and, thus, regulators of human skin homeostasis during aging.

Transcriptomic changes in the prefrontal cortex of rats as a function of age and cognitive engagement

Although changes in cognitive functions including attention are well documented in aging, the neurobiological basis for such alterations is not fully understood. Increasing evidence points towards the contribution of genetic factors in age-related cognitive decline. However, genetic studies have remained inconsistent in characterizing specific genes that could predict functional decline in aging. Here we utilized next generation RNA sequencing (RNA-seq) to identify patterns of differentially expressed genes in the prefrontal cortex (PFC), a brain region implicated in attention, of young and aged animals that were either cognitively trained or had limited cognitive engagement. Consistent with previous investigations, aging alone was associated with increased expression of genes involved in multiple facets of innate and adaptive immune responses. On the contrary, the expression of immunity-related transcripts was reduced by cognitive engagement. In addition, transcripts across a wide range of cellular processes, including those associated with neuronal remodeling and plasticity, were upregulated by this behavioral manipulation. Surprisingly, aged subjects accounted for higher mean counts of upregulated transcripts and lower mean counts for downregulated transcripts as compared to the young subjects. Because aged rats exhibited lower attentional capacities, it is plausible that transcriptional changes associated with performance in these animals were reflective of compensatory changes that occurred to cope with the declining integrity of PFC functioning. Interestingly, the effects of both aging and cognitive engagement resulted in an upregulation of transcripts linked to extracellular exosomes, suggesting such extracellular vesicles may moderate a reciprocal gene by environment interaction in order to facilitate the reorganization of PFC circuitry and maintain functionality. Taken together, these findings provide novel insights into the capacities of both cognitive engagement as well as aging to alter gene expression in the PFC, and how the effects of such dynamic factors relate to variation in age-related cognitive abilities.

Mechanisms and Impact of Symbiotic Phosphate Acquisition

Phosphorous is important for life but often limiting for plants. The symbiotic pathway of phosphate uptake via arbuscular mycorrhizal fungi (AMF) is evolutionarily ancient and today occurs in natural and agricultural ecosystems alike. Plants capable of this symbiosis can obtain up to all of the phosphate from symbiotic fungi, and this offers potential means to develop crops less dependent on unsustainable P fertilizers. Here, we review the mechanisms and insights gleaned from the fine-tuned signal exchanges that orchestrate the intimate mutualistic symbiosis between plants and AMF. As the currency of trade, nutrients have signaling functions beyond being the nutritional goal of mutualism. We propose that such signaling roles and metabolic reprogramming may represent commitments for a mutualistic symbiosis that act across the stages of symbiosis development.

Newly Generated and Non-Newly Generated "Immature" Neurons in the Mammalian Brain: A Possible Reservoir of Young Cells to Prevent Brain Aging and Disease?

Brain plasticity is important for translational purposes since most neurological disorders and brain aging problems remain substantially incurable. In the mammalian nervous system, neurons are mostly not renewed throughout life and cannot be replaced. In humans, the increasing life expectancy explains the increase in brain health problems, also producing heavy social and economic burden. An exception to the “static” brain is represented by stem cell niches leading to the production of new neurons. Such adult neurogenesis is dramatically reduced from fish to mammals, and in large-brained mammals with respect to rodents. Some examples of neurogenesis occurring outside the neurogenic niches have been reported, yet these new neurons actually do not integrate in the mature nervous tissue. Non-newly generated, “immature” neurons (nng-INs) are also present: Prenatally generated cells continuing to express molecules of immaturity (mostly shared with the newly born neurons). Of interest, nng-INs seem to show an inverse phylogenetic trend across mammals, being abundant in higher-order brain regions not served by neurogenesis and providing structural plasticity in rather stable areas. Both newly generated and nng-INs represent a potential reservoir of young cells (a “brain reserve”) that might be exploited for preventing the damage of aging and/or delay the onset/reduce the impact of neurological disorders.

Ethanol Exposure Increases miR-140 in Extracellular Vesicles: Implications for Fetal Neural Stem Cell Proliferation and Maturation

BACKGROUND

Neural stem cells (NSCs) generate most of the neurons of the adult brain in humans, during the mid-first through second-trimester period. This critical neurogenic window is particularly vulnerable to prenatal alcohol exposure, which can result in diminished brain growth. Previous studies showed that ethanol (EtOH) exposure does not kill NSCs, but, rather, results in their depletion by influencing cell cycle kinetics and promoting aberrant maturation, in part, by altering NSC expression of key neurogenic miRNAs. NSCs reside in a complex microenvironment rich in extracellular vesicles, shown to traffic miRNA cargo between cells.

METHODS

We profiled the miRNA content of extracellular vesicles from control and EtOH-exposed ex vivo neurosphere cultures of fetal NSCs. We subsequently examined the effects of one EtOH-sensitive miRNA, miR-140-3p, on NSC growth, survival, and maturation.

RESULTS

EtOH exposure significantly elevates levels of a subset of miRNAs in secreted extracellular vesicles. Overexpression of one of these elevated miRNAs, miR-140-3p, and its passenger strand relative, miR-140-5p, significantly increased the proportion of S-phase cells while decreasing the proportion of G₀ /G₁ cells compared to controls. In contrast, while miR-140-3p knockdown had minimal effects on the proportion of cells in each phase of the cell cycle, knockdown of miR-140-5p significantly decreased the proportion of cells in G₂ /M phase. Furthermore, miR-140-3p overexpression, during mitogen-withdrawal-induced NSC differentiation, favors astroglial maturation at the expense of neural and oligodendrocyte differentiation.

CONCLUSIONS

Collectively, the dysregulated miRNA content of extracellular vesicles following EtOH exposure may result in aberrant neural progenitor cell growth and maturation, explaining brain growth deficits associated with prenatal alcohol exposure.

Extracellular vesicles in renal physiology and clinical applications for renal disease

Many cells in the nephron release extracellular vesicles (EVs). EVs envelop nucleic acids, proteins, and lipids. The surfaces of EVs express donor cell-specific markers, ligands, and major histocompatibility complex molecules. They are involved in cell-to-cell communication, immune modulation, and the removal of unwanted materials from cells. EVs have been studied as biomarkers of specific diseases and have potential therapeutic applications. Recent research has emphasized the functions of EVs in the kidney. This review provides an overview of recent findings related to the roles of EVs in the nephron, and their utility as biomarkers and therapeutic factors in renal disease.