Identification and analysis of circulating exosomal microRNA in human body fluids

Exosomal miR-151-3p in saliva: A potential non-invasive marker for gastric cancer diagnosis and prognosis modulated by Sijunzi decoction (SJZD) in mice

Gastric cancer (GC) is one of the most prominent malignancies that originate in the epithelial cells of the gastric mucosa and is one of the main causes of cancer-related mortality worldwide. New circulating biomarkers of exosomal RNA might have great potential for non-invasive early prognosis of GC. Sijunzi Decoction (SJZD) is a typical representative formula of the method of benefiting Qi and strengthening the spleen in Traditional Chinese Medicine (TCM). However, the effects and mechanism of SJZD in treating GC remain unclear. This study looked for biomarkers of exosomal RNA for early prognosis of GC, and explored the mechanism of SJZD in treating GC. A gastric cancer model with spleen deficiency syndrome was established in nude mice, and the curative effects of SJZD were investigated. Differentially expressed miRNAs in plasma and saliva exosomes were sequenced and analyzed. Potential target genes of these miRNAs were predicted and applied for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway enrichment annotation. Overlapping miRNAs in saliva and plasma samples were analyzed, and qRT-PCR was performed for verification. miR-151a-3p was selected, and qRT-PCR further determined that miR-151a-3p was downregulated in saliva and plasma exosomes from the SJZD group. The intersected miR-151a-3p target genes were predicted and enriched in the extrinsic apoptotic signaling pathways. SJZD significantly ameliorates gastric cancer with spleen deficiency syndrome in mouse models, and exosomal miRNAs, particularly miR-151-3p, might be modulated by SJZD in plasma and saliva. The exosomal miR-151-3p in saliva may serve as a non-invasive potential marker for gastric cancer diagnosis and prognosis.

Exosomes in tumor-stroma crosstalk: Shaping the immune microenvironment in colorectal cancer

Colorectal cancer (CRC) is a multifaceted disease characterized by a complex interaction between tumor cells and the surrounding microenvironment. Within this intricate landscape, exosomes have emerged as pivotal players in the tumor-stroma crosstalk, influencing the immune microenvironment of CRC. These nano-sized vesicles, secreted by both tumoral and stromal cells, serve as molecular transporters, delivering a heterogeneous mix of biomolecules such as RNAs, proteins, and lipids. In the CRC context, exosomes exert dual roles: they promote tumor growth, metastasis, and immune escape by altering immune cell functions and activating oncogenic signaling pathways and offer potential as biomarkers for early CRC detection and treatment targets. This review delves into the multifunctional roles of exosomes in the CRC immune microenvironment, highlighting their potential implications for future therapeutic strategies and clinical outcomes.

Protein cargo of Nef-containing exosomal extracellular vesicles may predict HIV-associated Neurocognitive Impairment status

Exosomal extracellular vesicles (xEVs) in plasma and cerebrospinal fluid (CSF) of aviremic people living with HIV/AIDS (PLWHA) contain the HIV Negative factor (Nef) protein. However, the role of xEVs and Nef-containing-xEVs(xEV-Nef) in HIV-associated neuropathology is unknown. Here we performed a cross-sectional analysis of the content of xEVs derived from matched serum and CSF samples of PLWHAs diagnosed with either asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), or HIV-associated dementia (HAD). The overall objective was to determine whether the content of the matched xEVs derived plasma or CSF correlated with the neurocognitive impairment (NCI) status. The size and protein content of the xEVs were characterized via dynamic light scattering (DLS) and LC-MS/MS, respectively. xEV size was not significantly different between ANI, MND, or HAD groups. CSF of PLWHAs with NCI contained significantly more xEVs than matched plasma. xEV-Nef CSF concentration was elevated in PLWHAs with NCI and correlated with CD4 T-cell count. Plasma-derived xEV protein profiles from PLWHAs with ANI or MND differed from PLWHAs without NCI. Over-representation analysis using Reactome and KEGG databases show proteins involved in pathways associated with heme scavenging, signaling(MAP kinase and integrin-alpha),Toll-like receptor regulation, clot formation, complement, and cytosolic calcium level were elevated in MND. Pathways upregulated within the ANI group involved high-density lipid (HDL) remodeling, post-translational protein phosphorylation, and platelet activation. Overall, the data shows that xEV protein profiles of ANI and MND differ, suggesting protein profiles of peripheral xEVs, xEV-Nef, and CD4 T-cell count may discern NCI status.

Thiolate DNAzymes on Gold Nanoparticles for Isothermal Amplification and Detection of Mesothelioma-derived Exosomal PD-L1 mRNA

Catalytic DNAzymes have been used for isothermal amplification and rapid detection of nucleic acids, holding the potential for point-of-care testing applications. However, when Subzymes (universal substrate and DNAzyme) are tethered to the polystyrene magnetic microparticles via biotin-streptavidin bonds, the residual free Subzymes are often detached from the microparticle surface, which causes a significant degree of false positives. Here, we attached dithiol-modified Subzyme to gold nanoparticle and improved the limit of detection (LoD) by 200 times compared to that using magnetic microparticles. As a proof of concept, we applied our new method for the detection of exosomal programed cell-death ligand 1 (PD-L1) RNA. As the classical immune checkpoint, molecule PD-L1, found in small extracellular vesicles (sEVs, traditionally called exosomes), can reflect the antitumor immune response for predicting immunotherapy response. We achieved the LoD as low as 50 fM in detecting both the RNA homologous to the PD-L1 gene and exosomal PD-L1 RNAs extracted from epithelioid and nonepithelioid subtypes of mesothelioma cell lines, which only takes 8 min of reaction time. As the first application of isothermal DNAzymes for detecting exosomal PD-L1 RNA, this work suggests new point-of-care testing potentials toward clinical translations.

Urinary extracellular vesicles miRNA-A new era of prostate cancer biomarkers

Prostate cancer is the second most common male cancer worldwide showing the highest rates of incidence in Western Europe. Although the measurement of serum prostate-specific antigen levels is the current gold standard in PCa diagnosis, PSA-based screening is not considered a reliable diagnosis and prognosis tool due to its lower sensitivity and poor predictive score which lead to a 22%-43% overdiagnosis, unnecessary biopsies, and over-treatment. These major limitations along with the heterogeneous nature of the disease have made PCa a very unappreciative subject for diagnostics, resulting in poor patient management; thus, it urges to identify and validate new reliable PCa biomarkers that can provide accurate information in regard to disease diagnosis and prognosis. Researchers have explored the analysis of microRNAs (miRNAs), messenger RNAs (mRNAs), small proteins, genomic rearrangements, and gene expression in body fluids and non-solid tissues in search of lesser invasive yet efficient PCa biomarkers. Although the presence of miRNAs in body fluids like blood, urine, and saliva initially sparked great interest among the scientific community; their potential use as liquid biopsy biomarkers in PCa is still at a very nascent stage with respect to other well-established diagnostics and prognosis tools. Up to date, numerous studies have been conducted in search of PCa miRNA-based biomarkers in whole blood or blood serum; however, only a few studies have investigated their presence in urine samples of which less than two tens involve the detection of miRNAs in extracellular vesicles isolated from urine. In addition, there exists some discrepancy around the identification of miRNAs in PCa urine samples due to the diversity of the urine fractions that can be targeted for analysis such as urine circulating cells, cell-free fractions, and exosomes. In this review, we aim to discuss research output from the most recent studies involving the analysis of urinary EVs for the identification of miRNA-based PCa-specific biomarkers.

A Transcriptomic Liquid Biopsy Assay for Predicting Resistance to Neoadjuvant Therapy in Esophageal Squamous Cell Carcinoma

OBJECTIVE

The aim of this study was to establish a liquid-biopsy assay to predict response to neoadjuvant therapy (NAT) in esophageal squamous cell carcinoma (ESCC) patients.

SUMMARY BACKGROUND DATA

Pretreatment prediction of resistance to NAT is of great significance for the selection of treatment options in ESCC patients. In this study, we comprehensively translated tissue-based microRNA (miRNA) and messenger RNA (mRNA) expression biomarkers into a liquid biopsy assay.

METHODS

We analyzed 186 clinical ESCC samples, which included 128 formalin-fixed paraffin-embedded and a matched subset of 58 serum samples, from 2 independent institutions. We performed quantitative reverse-transcription polymerase chain reaction, and developed a resistance-prediction model using the logistic regression analyses.

RESULTS

We first evaluated the potential of 4-miRNAs and 3-mRNAs panel, which robustly predicted resistance to NAT [area under the curve (AUC): 0.85]. Moreover, addition of tumor size to this panel increased predictive potential to establish a combination signature (AUC: 0.92). We successfully validated this signature performance in independent cohort, and our model was more accurate when the signature was combined with clinical predictors (AUC: 0.81) to establish a NAT resistance risk (NATRR) model. Finally, we successfully translated our NATRR model into a liquid biopsy assay (AUC: 0.78), and a multivariate regression analysis revealed this model as an independent predictor for response to NAT (odds ratio: 6.10; P < 0.01).

CONCLUSIONS

We successfully developed a liquid biopsy-based assay that allows robust prediction of response to NAT in ESCC patients, and our assay provides fundamentals of developing precision-medicine.

Serum exosomal miR ‐16‐5p functions as a tumor inhibitor and a new biomarker for PD‐L1 inhibitor‐dependent immunotherapy in lung adenocarcinoma by regulating PD‐L1 expression

Objectives

We aimed at investigating whether serum exosomal miR‐16‐5p could be utilized as an immunotherapy biomarker in lung adenocarcinoma (LUAD) patients administered by programmed cell death ligand‐1 (PD‐L1) inhibitors, and to evaluate its functions in LUAD progression.

Methods

Sixty LUAD sufferers and 20 healthy controls (HCs) were covered in this work. We applied both IHC and WB to examine PD‐L1 level in clinical tissue samples and utilized WB to quantify PD‐L1 expression in LUAD cells and LUAD xenograft tissues, respectively. Transmission electron microscopy (TEM), WB, and nanoparticle tracking analysis (NTA) were executed to confirm the exosomes isolated from serum specimens and cell culture media. To quantify of exosomal miR‐16‐5p level from serum and culture medium of cultured cell, qRT‐PCR experiment was utilized. The connection between tissue PD‐L1 level and serum exosomal miR‐16‐5p expression in PD‐L1‐positive sufferers administered by PD‐L1 inhibitors was verified using Spearman correlation coefficient analysis. In addition, the overall survival (OS) and progression‐free survival (PFS) rates among PD‐L1 inhibitor managed sufferers were acquired through a follow‐up visit. Finally, we used a group of assays, including 5‐bromo‐2′‐dexoyuridine (BrdU) and colony formation test, wound healing experiment, flow cytometry, and nude mice xenograft experiment, to explore the functions of circulating exosomal miR‐16‐5p on LUAD cell proliferation, apoptosis, and migration, as well as tumor development, respectively.

Results

PD‐L1 expression was positively related to T stage (tumor size stage), and PD‐L1 inhibitor treatment reduced the PD‐L1 expression and mitigated T stage in PD‐L1‐positive LUAD sufferers. For PD‐L1‐positive LUAD sufferers, elevated PD‐L1 expression or reduced serum exosomal miR‐16‐5p level were linked to longer PFS and OS upon PD‐L1 inhibitor treatment. The number of exosomes in patient's serum was more than that in the serum of healthy individuals, and PD‐L1 inhibitor treatment decreased the number of serum‐derived exosomes in PD‐L1‐positive LUAD sufferers. Exosome‐derived miR‐16‐5p was downregulated in patient's serum and cell culture medium, and this was negatively linked to tumor stage and PD‐L1 expression. Meanwhile, PD‐L1 inhibitor treatment could increase the serum exosomal miR‐16‐5p expression, and the expression change of serum exosomal miR‐16‐5p was diametrically related to PD‐L1 after the treatment. Moreover, the overexpression of PD‐L1 accelerated tumor growth and decreased the exosomal miR‐16‐5p content in cell culture media, while exosomal miR‐16‐5p overexpression in cell culture media inhibited tumor development by decreasing the PD‐L1 expression. Exosomal miR‐16‐5p overexpression in cell culture media also depressed LUAD cell proliferation and migration, and stimulated cell apoptosis, especially in the cells which cultured in the mediums with PD‐L1 inhibitor in vitro.

Conclusions

Serum exosomal miR‐16‐5p may be a latent tumor inhibitor and a new biomarker for PD‐L1 inhibitor‐dependent immunotherapy in LUAD by regulating the PD‐L1 expression.

Exosomes for Regulation of Immune Responses and Immunotherapy

Exosomes are membrane-enveloped nanosized (30–150 nm) extracellular vesicles of endosomal origin produced by almost all cell types and encompass a multitude of functioning biomolecules. Exosomes have been considered crucial players of cell-to-cell communication in physiological and pathological conditions. Accumulating evidence suggests that exosomes can modulate the immune system by delivering a plethora of signals that can either stimulate or suppress immune responses, which have potential applications as immunotherapies for cancer and autoimmune diseases. Here, we discuss the current knowledge about the active biomolecular components of exosomes that contribute to exosomal function in modulating different immune cells and also how these immune cell-derived exosomes play critical roles in immune responses. We further discuss the translational potential of engineered exosomes as immunotherapeutic agents with their advantages over conventional nanocarriers for drug delivery and ongoing clinical trials.

New hope for intervertebral disc degeneration: bone marrow mesenchymal stem cells and exosomes derived from bone marrow mesenchymal stem cell transplantation

Bone marrow mesenchymal stem cells (BMSCs), multidirectional cells with self-renewal capacity, can differentiate into many cell types and play essential roles in tissue healing and regenerative medicine. Cell experiments and in vivo research in animal models have shown that BMSCs can repair degenerative discs by promoting cell proliferation and expressing extracellular matrix (ECM) components, such as type II collagen and protein-polysaccharides. Delaying or reversing the intervertebral disc (IVD) degeneration (IDD) process at an etiological level may be an effective strategy. However, despite increasingly in-depth research, some deficiencies in cell transplantation timing and strategy remain, preventing the clinical application of cell transplantation. Exosomes exhibit the characteristics of the mother cells from which they were secreted and can inhibit nucleus pulposus (NP) cell (NPC) apoptosis and delay IDD through intercellular communication. Furthermore, the use of exosomes effectively avoids problems associated with cell transplantation, such as immune rejection. This manuscript introduces almost all of the BMSCs and exosomes derived from BMSCs (BMSCs-Exos) described in the IDD literature. Many challenges regarding the use of cell transplantation and therapeutic exosome intervention for IDD remain to be overcome.

Comparison of methods for pre-processing, exosome isolation, and RNA extraction in unpasteurized bovine and human milk

Milk is a highly complex, heterogeneous biological fluid that contains non-nutritive, bioactive extracellular vesicles called exosomes. Characterization of milk-derived exosomes (MDEs) is challenging due to the lack of standardized methods that are currently being used for milk pre-processing, storage, and exosome isolation. In this study, we tested: 1) three pre-processing methods to remove cream, fat, cellular debris, and casein proteins from bovine milk to determine whether pre-processing of whole milk prior to long-term storage improves MDE isolations, 2) the suitability of two standard exosome isolation methods for MDE fractionation, and 3) four extraction protocols for obtaining high quality RNA from bovine and human MDEs. MDEs were characterized via Transmission Electron Microscopy (TEM), Nanoparticle Tracking Analysis (NTA), and western immunoblotting for CD9, CD63, and Calnexin protein markers. We also present an optimized method of TEM sample preparation for MDEs. Our results indicate that: 1) Removal of cream and fat globules from unpasteurized bovine milk, prior to long-term storage, improves the MDE yield but not purity, 2) Differential ultracentrifugation (DUC) combined with serial filtration is better suited for bovine MDE isolation compared to ExoQuick (EQ) combined with serial filtration, however both methods were comparable for human milk, and 3) TRIzol LS is better suited for RNA extraction from bovine MDEs isolated by EQ and DUC methods. 4) TRIzol LS, TRIzol+RNA Clean and Concentrator, and TRIzol LS+RNA Clean and Concentrator methods can be used for RNA extractions from human MDEs isolated by EQ, yet the TRIzol LS method is better suited for human MDEs isolated by DUC. The QIAzol + miRNeasy Mini Kit produced the lowest RNA yield for bovine and human MDEs.

A Circulating Exosome RNA Signature Is a Potential Diagnostic Marker for Pancreatic Cancer, a Systematic Study

Simple Summary

Most patients with pancreatic cancer are diagnosed at an advanced stage due to the lack of tools with high sensitivity and specificity for early detection. Aberrant gene expression occurs in pancreatic cancer, which can be packaged into nanoparticles (also known as exosomes or nano-sized extracellular vesicles) and then released into blood. In this study, we aimed to evaluate the diagnostic value of a circulating exosome RNA signature in pancreatic cancer. Our findings indicate that the circulating exosome RNA signature is a potential marker for the early detection or diagnosis of pancreatic cancer.

Abstract

Several exosome proteins, miRNAs and KRAS mutations have been investigated in the hope of carrying out the early detection of pancreatic cancer with high sensitivity and specificity, but they have proven to be insufficient. Exosome RNAs, however, have not been extensively evaluated in the diagnosis of pancreatic cancer. The purpose of this study was to investigate the potential of circulating exosome RNAs in pancreatic cancer detection. By retrieving RNA-seq data from publicly accessed databases, differential expression and random-effects meta-analyses were performed. The results showed that pancreatic cancer had a distinct circulating exosome RNA signature in healthy individuals, and that the top 10 candidate exosome RNAs could distinguish patients from healthy individuals with an area under the curve (AUC) of 1.0. Three (HIST2H2AA3, LUZP6 and HLA-DRA) of the 10 genes in exosomes had similar differential patterns to those in tumor tissues based on RNA-seq data. In the validation dataset, the levels of these three genes in exosomes displayed good performance in distinguishing cancer from both chronic pancreatitis (AUC = 0.815) and healthy controls (AUC = 0.8558), whereas a slight difference existed between chronic pancreatitis and healthy controls (AUC = 0.586). Of the three genes, the level of HIST2H2AA3 was positively associated with KRAS status. However, there was no significant difference in the levels of the three genes across the disease stages (stages I–IV). These findings indicate that circulating exosome RNAs have a potential early detection value in pancreatic cancer, and that a distinct exosome RNA signature exists in distinguishing pancreatic cancer from healthy individuals.

Exosomes as Emerging Biomarker Tools in Neurodegenerative and Neuropsychiatric Disorders-A Proteomics Perspective

Exosomes are synthesized and secreted by different cell types and contain proteins, lipids, metabolites and RNA species that reflect the physiological status of the cell of origin. As such, exosomes are increasingly being used as a novel reservoir for disease biomarker discovery. However, isolation of exosomes can be challenging due to their nonuniformity of shape and variable tissue of origin. Moreover, various analytical techniques used for protein detection and quantitation remain insensitive to the low amounts of protein isolated from exosomes. Despite these challenges, techniques to improve proteomic yield and increase protein dynamic range continue to improve at a rapid rate. In this review, we highlight the importance of exosome proteomics in neurodegenerative and neuropsychiatric disorders and the associated technical difficulties. Furthermore, current progress and technological advancements in exosome proteomics research are discussed with an emphasis on disease-associated protein biomarkers.

Unraveling the dark matter, long non-coding RNAs, in male reproductive diseases: A narrative review

Recent advances in human transcriptome have revealed the fundamental and functional roles of long non-coding RNA in the susceptibility to diverse diseases and pathological conditions. They participate in wide range of biological processes such as the modulating of chromatin structure, transcription, translation, and post-translation modification. In addition, based on their unique expression profiles and their association with clinical abnormalities such as those of related to male reproductive diseases, they can be used to develop therapeutic methods and biomarkers for screening of the diseases. In this study, we will review the identified lncRNAs and their molecular functions in the pathogenesis of male reproductive diseases such as prostate cancer, benign prostatic hyperplasia, prostatitis, testicular cancer, varicocele, and sperm abnormalities.

The role of tumor-isolated exosomes on suppression of immune reactions and cancer progression: A systematic review

Background: Exosomes are extracellular cells (EVs) emancipated by various cell types and are involved in cell-to-cell transmission. In cancer diseases, exosomes emerge as local and systemic cells to cell mediators of oncogenic information and play a significant role in the advancement of cancer through the horizontal transfer of various molecules, such as proteins and miRNAs.

Methods: In this study, 66 articles from PubMed, MEDLINE, Science Direct, Cochrane, EMBASE, and Scopus were used as English sources.

Results: The biological distribution of cancer cell-derived exosomes in tumor tissue is an important factor in detecting their role in tumor increase; on the other hand, a limited number of studies have examined the biodistribution of exosomes in tumor tissues. While exosomes function as cancer biomarkers and support cancer treatment, we have a long way to improve the antitumor treatment of exosomes and develop exosome-based cancer diagnostic and therapeutic strategies.

Conclusion: This review describes the science and significance of cancer pathogenesis and exosomes relative to cancer treatment resistance.

Surface plasmon resonance imaging-based biosensor for multiplex and ultrasensitive detection of NSCLC-associated exosomal miRNAs using DNA programmed heterostructure of Au-on-Ag

Exosomal miRNAs are potential tumor biomarkers for early diagnosis of non-small cell lung cancer (NSCLC). Herein, a surface plasmon resonance imaging (SPRi)-based biosensor was developed for simultaneous detection of multiplex NSCLC-associated exosomal miRNAs in a clinical sample using Au-on-Ag heterostructure and DNA tetrahedral framework (DTF). Exosomal miRNAs are captured by various DTF probes immobilized on the gold array chip. Subsequently, single-stranded DNA (ssDNA) functionalized silver nanocube (AgNC) hybridizes with the captured exosomal miRNAs and then the ssDNA-coated Au nanoparticles assembled on the surface of AgNC, forming Au-on-Ag heterostructures as essential labels to realize amplified SPR response. With the aid of DNA programmed Au-on-Ag heterostructure and DTF, the SPRi-based biosensor exhibits wide detection range from 2 fM to 20 nM, ultralow limit of detection of 1.68 fM, enhanced capture efficiency, and improved antifouling capability. Furthermore, the biosensor enables accurate discrimination of NSCLC patients based on detection results of exosomal miRNAs. Overall, this developed biosensor is a promising tool for multiplex exosomal miRNAs detection, providing a new possibility for early diagnosis of NSCLC.

A facile, rapid, high-throughput extracellular vesicles analytical platform for cancer detection

Cell-derived nanoparticles, so called Extracellular Vesicles (EVs), can reflect the physiological or pathological conditions of donor cells and can provide promising biomarkers for the non-invasive diagnosis of cancers. Size-based purification method is one of the common strategies for rapid extracting EVs from biosamples, but the downstream clinical studies still remain challenges in EV enrichment with high purity and high yield. Here, such challenges could be fulfilled through the development of an arrayed Exosome Purification and Operation System (Exo-POS) for efficiently isolating EVs from complex biofluids. Human urinary EVs with mean size of approximately 170 nm were isolated successfully from donors within 30 min, and the purification of individual samples were performable in parallel. Samples purified by Exo-POS showed detectable EV-specific biomarkers and less protein impurities than that by ultrafiltration method. The results also demonstrate the great purification ability of Exo-POS to discriminate between the EV-derived proteomic and genomic expressions of cancer patients and healthy controls. The developed platform can easily be adapted to retrieve EVs from biological samples for the downstream analysis, demonstrating its potential for both rapid clinical diagnosis and biomarker discovery.

Different Exosomal microRNA Profile in Aquaporin-4 Antibody Positive Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS) are inflammatory demyelinating diseases of the central nervous system. Exosomal microRNAs (miRNAs) are emerging biomarkers for demyelinating diseases. In this study, 52 aquaporin-4 antibody serum-positive NMOSD patients, 18 relapsing-remitting multiple sclerosis (RRMS) patients and 17 healthy controls (HCs) were included for the next-generation sequencing (NGS). To validate the NGS results, the valuable miRNAs were selected for validation by real-time quantitative polymerase chain reaction in another cohort of patients, comprising 31 NMOSD patients and 14 HCs. In addition, these miRNAs were also validated in a longitudinal study. NGS data revealed the exosomal miRNAs profile in NMOSD patients was different from HCs. Among those potential exosomal miRNAs which can distinguish NMOSD status, hsa-miR-122-3p and hsa-miR-200a-5p were the most abundant miRNAs. In addition, hsa-miR-122-3p and hsa-miR-200a-5p were significantly upregulated in the serum exosome of relapsing NMOSD compared with that in remitting NMOSD. Hsa-miR-122-3p and hsa-miR-200a-5p had positive correlations with disease severity in NMOSD patients. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the MAPK, Wnt and Ras signaling pathways were enriched. Further biological function analysis demonstrated that these two miRNAs might be involved in the immunoregulation of NMOSD pathogenesis. Our results indicated that miRNAs delivered by exosomes could be applied as potential biomarkers for NMOSD.

The versatile roles and clinical implications of exosomal mRNAs and microRNAs in cancer

Extracellular vesicles (EVs), which include exosomes, microvesicles, and apoptotic bodies, are nanosized structures that are secreted by various cells and act as important mediators in intercellular communication. Recent studies have shown that exosomes carrying bioactive molecules are generated from multivesicular bodies and are present in various body fluids. mRNAs and microRNAs (miRNAs) are encapsulated in exosomes and have been found to be involved in multiple pathophysiological processes. Here, we provide a review of tumor-associated exosomal mRNAs and miRNAs and their roles in metastasis and drug resistance. In particular, we emphasize their clinical application potential as diagnostic and prognostic biomarkers of cancer and in cancer therapy.

Exosomal PD-L1: Roles in Tumor Progression and Immunotherapy

The use of immune checkpoint therapies targeting programmed death-1 (PD-1) and its ligand (PD-L1) continue to show limited durable success in clinical cases despite widespread application. While some patients achieve complete responses and disease remission, others are completely resistant to the therapy. Recent evidence in the field suggests that tumor-derived exosomes could be responsible for mediating systemic immunosuppression that antagonizes anti-PD-1 checkpoint therapy. In this Opinion article, we discuss our claim that endogenous tumor exosomal PD-L1 and tumor-derived exosome-induced PD-L1 are two of the most notable mechanisms of exosome-mediated resistance against antitumor immunity and we discuss how this resistance could directly influence immune checkpoint therapy failure.

RNA cargos in extracellular vesicles derived from blood serum in pancreas associated conditions

Exosomes are extracellular vesicles which are released from healthy and tumor cells into blood circulation. Unique biomolecular cargos such as RNA and protein are loaded in these vesicles. These molecules may have biological functions such as signaling, cell communications and have the potential to be analyzed as biomarkers. In this initial study, we describe the analysis of exosomes in the serum of healthy subjects, intraductal papillary mucosal neoplasms and pancreatic ductal adenocarcinoma including the characterization of their RNA cargos by next generation sequencing (EXO-NGS). Results indicate the presence of a wide variety of RNAs including mRNA, miRNA, lincRNA, tRNA and piRNA in these vesicles. Based on the differential mRNA expression observed upon EXO-NGS analysis, we independently evaluated two protein coding genes, matrix metalloproteinase-8 (MMP-8) and transcription factor T-Box 3 (TBX3) by qRT-PCR for selective expression in the serum samples. Results indicate a variable expression pattern of these genes across serum samples between different study groups. Further, qRT-PCR analysis with the same serum exosomes processed for EXO-NGS, we observed two long non-coding RNAs, malat-1 and CRNDE to be variably expressed. Overall, our observations emphasize the potential value of different exosome components in distinguishing between healthy, premalignant and malignant conditions related to the pancreas.

Circulating Exosomal microRNAs as Biomarkers of Systemic Lupus Erythematosus

OBJECTIVES

Many studies indicate that microRNAs (miRNAs) could be potential biomarkers for various diseases. The purpose of this study was to investigate the clinical value of serum exosomal miRNAs in systemic lupus erythematosus (SLE).

METHODS

Serum exosomes were isolated from 38 patients with SLE and 18 healthy controls (HCs). The expression of miR-21, miR-146a and miR-155 within exosomes was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Using receiver operating characteristic (ROC) curves, we evaluated the diagnostic value of exosomal miRNAs.

RESULTS

Exosomal miR-21 and miR-155 were upregulated (p<0.01), whereas miR-146a expression (p<0.05) was downregulated in patients with SLE, compared to that in HCs. The expression of miR-21 (p<0.01) and miR-155 (p<0.05) was higher in SLE patients with lupus nephritis (LN) than in those without LN (non-LN). The analysis of ROC curves revealed that the expression of miR-21 and miR-155 showed a potential diagnostic value for LN. Furthermore, miR-21 (R=0.44, p<0.05) and miR-155 (R=0.33, p<0.05) were positively correlated with proteinuria. The expression of miR-21 was negatively associated with anti-SSA/Ro antibodies (R=-0.38, p<0.05), and that of miR-146a was negatively associated with anti-dsDNA antibodies (R=-0.39, p<0.05).

CONCLUSIONS

These findings suggested that exosomal miR-21 and miR-155 expression levels may serve as potential biomarkers for the diagnosis of SLE and LN.

Techniques Associated with Exosome Isolation for Biomarker Development: Liquid Biopsies for Ovarian Cancer Detection

Ovarian cancer is the leading gynecological malignancy worldwide. This is attributed to the fact that the disease is often diagnosed at an advanced stage, where the survival rates drop from approximately 90% (detection at an early stage) to 20%. Furthermore, ovarian cancer is not associated with overt physical symptoms. Thus, there is an urgent need for a highly sensitive and minimally invasive biomarker for the early detection of ovarian cancer. However, this continues to remain an unmet clinical need, as several proposed techniques have shown low sensitivity and specificity, with poor positive and negative predictive values. The quest for an ideal biomarker has bought exosomes to the forefront. Exosomes are small extracellular vesicles of an endocytic origin, which can encapsulate genetic information, in the form of proteins and miRNAs. They are released by multiple cell types and are involved in intercellular communication, through the transfer of their cargo. The process of exosome biogenesis allows for the packaging of molecules from both membranous and cytosolic origins. Therefore, exosomes are representations of the releasing cell, and thus provide an insight into the cellular environment. Furthermore, exosomal encapsulation of molecules such as proteins and miRNAs can prevent degradation, making exosomes an ideal biomarker source. Thus, this chapter provides an overview of ovarian cancer, the potential of exosomes as an early detection biomarker, and the different methods associated with the isolation of different vesicle subpopulations, and exosome enrichment.

Mitochondrial protein enriched extracellular vesicles discovered in human melanoma tissues can be detected in patient plasma

Extracellular vesicles (EVs), including exosomes and microvesicles, are secreted from all cells, and convey messages between cells in health and disease. However, the diversity of EV subpopulations is only beginning to be explored. Since EVs have been implicated in tumour microenvironmental communication, we started to determine the diversity of EVs specifically in this tissue. To do this, we isolated EVs directly from patient melanoma metastatic tissues. Using EV membrane isolation and mass spectrometry analysis, we discovered enrichment of mitochondrial membrane proteins in the melanoma tissue-derived EVs, compared to non-melanoma-derived EVs. Interestingly, two mitochondrial inner membrane proteins MT-CO2 (encoded by the mitochondrial genome) and COX6c (encoded by the nuclear genome) were highly prevalent in the plasma of melanoma patients, as well as in ovarian and breast cancer patients. Furthermore, this subpopulation of EVs contains active mitochondrial enzymes. In summary, tumour tissues are enriched in EVs with mitochondrial membrane proteins and these mitochondrial membrane proteins can be detected in plasma and are increased in melanoma, ovarian cancer as well as breast cancer.

What information can be obtained from the tears of a patient with primary open angle glaucoma?

Since tears are a biological fluid, they have a potential diagnostic value for ophthalmic diseases. The aim of this study was to compare tear supernatants and pellets obtained from patients suffering from primary open angle glaucoma (POAG) and healthy persons (HPs) using transmission electron microscopy (TEM) and molecular biological methods. Tear supernatants and pellets were prepared using ultrafiltration and ultracentrifugation and were examined by negative staining and immunogold labelling TEM. DNA of the pellets was isolated, quantified and sequenced using a MiSeq (Illumina, USA) genomic sequencer with the Reagent Kit v3 (600 cycles, Illumina, USA). MicroRNA was isolated and quantified from the pellets; miR-146b, miR-16 and miR-126 were detected using TaqMan MicroRNA Assays (Applied Biosystems, USA). TEM of tear supernatants from both POAG patients and HPs revealed identical constituents: spherical or cup-shaped vesicles, "non-vesicles", cell debris and macromolecular aggregates. Pellets of POAG patients and HPs contained small extracellular vesicles (sEVs) non-labelled vesicles and "non-vesicles"; pellets of sick persons also contained sEVs with "a capsule". POAG-patient tear pellets showed elevated concentrations of genomic ds-DNA and SINE-repeats, and different expressions of miR-146b, miR-16 and miR-126 and a different set of bacterial DNA in comparison with pellets obtained from the tears of HPs. The data obtained indicate that the tears of HPs and POAG patients could serve as an object for TEM studies and as a source of sEV-containing preparations (pellets), which, in turn, could be used for the isolation and study of genomic ds-DNA and RNA. Our data provide the basis for using tears for diagnostic applications.

Genome-wide interrogation of extracellular vesicle biology using barcoded miRNAs

Extracellular vesicles mediate transfer of biologically active molecules between neighboring or distant cells, and these vesicles may play important roles in normal physiology and the pathogenesis of multiple disease states including cancer. However, the underlying molecular mechanisms of their biogenesis and release remain unknown. We designed artificially barcoded, exosomal microRNAs (bEXOmiRs) to monitor extracellular vesicle release quantitatively using deep sequencing. We then expressed distinct pairs of CRISPR guide RNAs and bEXOmiRs, enabling identification of genes influencing bEXOmiR secretion from Cas9-edited cells. This approach uncovered genes with unrecognized roles in multivesicular endosome exocytosis, including critical roles for Wnt signaling in extracellular vesicle release regulation. Coupling bEXOmiR reporter analysis with CRISPR-Cas9 screening provides a powerful and unbiased means to study extracellular vesicle biology and for the first time, to associate a nucleic acid tag with individual membrane vesicles.

Dysregulation of microRNAs in autoimmune diseases: Pathogenesis, biomarkers and potential therapeutic targets

MicroRNAs (miRNAs) are small, single-stranded, endogenous non-coding RNAs that repress the expression of target genes via post-transcriptional mechanisms. Due to their broad regulatory effects, the precisely regulated, spatial-specific and temporal-specific expression of miRNAs is fundamentally important to various biological processes including the immune homeostasis and normal function of both innate and adaptive immune response. Aberrance of miRNAs is implicated in the development of various human diseases, especially cancers. Increasing evidence has revealed a dysregulated expression pattern of miRNAs in autoimmune diseases, among which many play key roles in the pathogenesis. In this review we summarize these findings on miRNA dysregulation implicated in autoimmune diseases, focusing on four representative systemic autoimmune diseases, i.e. systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and dermatomyositis. The causes of the dysregulation of miRNA expression in autoimmune diseases may include genetic and epigenetic variants, and various environmental factors. Further understanding of miRNA dysregulation and its mechanisms during the development of different autoimmune diseases holds enormous potential to bring about novel therapeutic targets or strategies for these complex human disorders, as well as novel circulating or exosomal miRNA biomarkers.

Pellet-free isolation of human and bovine milk extracellular vesicles by size-exclusion chromatography

Studies have suggested that nanoscale extracellular vesicles (EV) in human and bovine milk carry immune modulatory properties which could provide beneficial health effects to infants. In order to assess the possible health effects of milk EV, it is essential to use isolates of high purity from other more abundant milk structures with well-documented bioactive properties. Furthermore, gentle isolation procedures are important for reducing the risk of generating vesicle artefacts, particularly when EV subpopulations are investigated. In this study, we present two isolation approaches accomplished in three steps based on size-exclusion chromatography (SEC) resulting in effective and reproducible EV isolation from raw milk. The approaches do not require any EV pelleting and can be applied to both human and bovine milk. We show that SEC effectively separates phospholipid membrane vesicles from the primary casein and whey protein components in two differently obtained casein reduced milk fractions, with one of the fractions obtained without the use of ultracentrifugation. Milk EV isolates were enriched in lactadherin, CD9, CD63 and CD81 compared to minimal levels of the EV-marker proteins in other relevant milk fractions such as milk fat globules. Nanoparticle tracking analysis and electron microscopy reveals the presence of heterogeneous sized vesicle structures in milk EV isolates. Lipid analysis by thin layer chromatography shows that EV isolates are devoid of triacylglycerides and presents a phospholipid profile differing from milk fat globules surrounded by epithelial cell plasma membrane. Moreover, the milk EV fractions are enriched in RNA with distinct and diverging profiles from milk fat globules. Collectively, our data supports that successful milk EV isolation can be accomplished in few steps without the use of ultracentrifugation, as the presented isolation approaches based on SEC effectively isolates EV in both human and bovine milk.

Multiple sclerosis: Serum-derived exosomes express myelin proteins

BACKGROUND

Exosomes are small extracellular vesicles that provide cell-to-cell communication and are involved in immunoregulation.

OBJECTIVE

To investigate serum exosomes for the presence of myelin proteins outside the central nervous system (CNS) and their role in multiple sclerosis (MS).

METHODS

Serum, cerebrospinal fluid (CSF), and peripheral blood mononuclear cell (PBMC) samples were collected from 45 patients with relapsing-remitting MS (RRMS), 30 patients with secondary progressive MS (SPMS), and 45 healthy controls. Exosomes were isolated using a polymer formulation method, and their size, concentration, and CNS myelin protein contents were measured by a nanoparticle tracking analysis, enzyme-linked immunosorbent assays, and Western blot.

RESULTS

We found that exosomes expressed three major myelin proteins, myelin basic protein, proteolipid protein, and myelin oligodendrocyte glycoprotein (MOG). Exosomal content of MOG strongly correlated with disease activity and was highest in RRMS patients in relapse and in SPMS patients. Serum-derived exosomes induced proliferation of MOG-T cell receptor transgenic T cells confirming that serum exosomes maintained MOG immunogenicity.

CONCLUSION

Exosomes isolated outside CNS tissue expressed myelin proteins, and the presence of MOG correlated strongly with disease activity. We conclude that exosomes might enhance and/or perpetuate anti-myelin immune reactions in MS and may provide novel markers of disease activity.

Proteomic Analysis of Exosomes and Exosome-Free Conditioned Media From Human Osteosarcoma Cell Lines Reveals Secretion of Proteins Related to Tumor Progression

Osteosarcomas are the most prevalent bone tumors in pediatric patients, but can also occur later in life. Bone tumors have the potential to metastasize to lung and occasionally other vital organs. To understand how osteosarcoma cells interact with their micro-environment to support bone tumor progression and metastasis, we analyzed secreted proteins and exosomes from three human osteosarcoma cell lines. Exosome isolation was validated by transmission electron microscopy (TEM) and immuno-blotting for characteristic biomarkers (CD63, CD9, and CD81). Exosomal and soluble proteins (less than 100 kDa) were identified by mass spectrometry analysis using nanoLC-MS/MS and classified by functional gene ontology clustering. We identified a secretome set of >3,000 proteins for both fractions, and detected proteins that are either common or unique among the three osteosarcoma cell lines. Protein ontology comparison of proteomes from exosomes and exosome-free fractions revealed differences in the enrichment of functional categories associated with different biological processes, including those related to tumor progression (i.e., angiogenesis, cell adhesion, and cell migration). The secretome characteristics of osteosarcoma cells are consistent with the pathological properties of tumor cells with metastatic potential. J. Cell. Biochem. 118: 351-360, 2017. © 2016 Wiley Periodicals, Inc.

Methods for the physical characterization and quantification of extracellular vesicles in biological samples

BACKGROUND

Our body fluids contain a multitude of cell-derived vesicles, secreted by most cell types, commonly referred to as extracellular vesicles. They have attracted considerable attention for their function as intercellular communication vehicles in a broad range of physiological processes and pathological conditions. Extracellular vesicles and especially the smallest type, exosomes, have also generated a lot of excitement in view of their potential as disease biomarkers or as carriers for drug delivery. In this context, state-of-the-art techniques capable of comprehensively characterizing vesicles in biological fluids are urgently needed.

SCOPE OF REVIEW

This review presents the arsenal of techniques available for quantification and characterization of physical properties of extracellular vesicles, summarizes their working principles, discusses their advantages and limitations and further illustrates their implementation in extracellular vesicle research.

MAJOR CONCLUSIONS

The small size and physicochemical heterogeneity of extracellular vesicles make their physical characterization and quantification an extremely challenging task. Currently, structure, size, buoyant density, optical properties and zeta potential have most commonly been studied. The concentration of vesicles in suspension can be expressed in terms of biomolecular or particle content depending on the method at hand. In addition, common quantification methods may either provide a direct quantitative measurement of vesicle concentration or solely allow for relative comparison between samples.

GENERAL SIGNIFICANCE

The combination of complementary methods capable of detecting, characterizing and quantifying extracellular vesicles at a single particle level promises to provide new exciting insights into their modes of action and to reveal the existence of vesicle subpopulations fulfilling key biological tasks.

Circulating MicroRNAs: Association with Lung Function in Asthma

BACKGROUND

MicroRNAs are key transcriptional and network regulators previously associated with asthma susceptibility. However, their role in relation to asthma severity has not been delineated.

OBJECTIVE

We hypothesized that circulating microRNAs could serve as biomarkers of changes in lung function in asthma patients.

METHODS

We isolated microRNAs from serum samples obtained at randomization for 160 participants of the Childhood Asthma Management Program. Using a TaqMan microRNA array containing 754 microRNA primers, we tested for the presence of known asthma microRNAs, and assessed the association of the individual microRNAs with lung function as measured by FEV1/FVC, FEV1% and FVC%. We further tested the subset of FEV1/FVC microRNAs for sex-specific and lung developmental associations.

RESULTS

Of the 108 well-detected circulating microRNAs, 74 (68.5%) had previously been linked to asthma susceptibility. We found 22 (20.3%), 4 (3.7%) and 8 (7.4%) microRNAs to be associated with FEV1/FVC, FEV1% and FVC%, respectively. 8 (of 22) FEV1/FVC, 3 (of 4) FEV1% and 1 (of 8) FVC% microRNAs had functionally validated target genes that have been linked via genome wide association studies to asthma and FEV1 change. Among the 22 FEV1/FVC microRNAs, 9 (40.9%) remain associated with FEV1/FVC in boys alone in a sex-stratified analysis (compared with 3 FEV1/FVC microRNAs in girls alone), 7 (31.8%) were associated with fetal lung development, and 3 (13.6%) in both. Ontology analyses revealed enrichment for pathways integral to asthma, including PPAR signaling, G-protein coupled signaling, actin and myosin binding, and respiratory system development.

CONCLUSIONS

Circulating microRNAs reflect asthma biology and are associated with lung function differences in asthmatics. They may represent biomarkers of asthma severity.

Vesicle-MaNiA: extracellular vesicles in liquid biopsy and cancer

Normal and tumor cells shed vesicles to the environment. Within the large family of extracellular vesicles, exosomes and microvesicles have attracted much attention in the recent years. Their interest ranges from mediators of cancer progression, inflammation, immune regulation and metastatic niche regulation, to non-invasive biomarkers of disease. In this respect, the procedures to purify and analyze extracellular vesicles have quickly evolved and represent a source of variability for data integration in the field. In this review, we provide an updated view of the potential of exosomes and microvesicles as biomarkers and the available technologies for their isolation.

MicroRNAs May Serve as Emerging Molecular Biomarkers for Diagnosis and Prognostic Assessment or as Targets for Therapy in Gastric Cancer

Gastric cancer (GC) is one of the most common cancers, with high incidences in East Asia countries. Most GC patients have been reported with low early diagnosis rate and show extremely poor prognosis. Therefore, it is necessary to develop novel and more sensitive biomarkers to improve early diagnosis and therapy in order to provide longer survival and better quality of life for gastric cancer patients. MicroRNAs (miRNAs) play crucial roles in GC development and progression. miRNAs have emerged as a novel molecular biomarker for cancer diagnosis, prognosis and therapy with surprising stability in tissues, serum or other body fluids. This review summarizes major advances in our current knowledge about potential miRNA biomarkers for GC that have been reported in the past two years.

The biology and function of exosomes in cancer

Humans circulate quadrillions of exosomes at all times. Exosomes are a class of extracellular vesicles released by all cells, with a size range of 40-150 nm and a lipid bilayer membrane. Exosomes contain DNA, RNA, and proteins. Exosomes likely remove excess and/or unnecessary constituents from the cells, functioning like garbage bags, although their precise physiological role remains unknown. Additionally, exosomes may mediate specific cell-to-cell communication and activate signaling pathways in cells they fuse or interact with. Exosomes are detected in the tumor microenvironment, and emerging evidence suggests that they play a role in facilitating tumorigenesis by regulating angiogenesis, immunity, and metastasis. Circulating exosomes can be used as liquid biopsies and noninvasive biomarkers for early detection, diagnosis, and treatment of cancer patients.

Exosomal miRNAs as biomarkers of recurrent lung cancer

Prognosis of lung cancer still remains grim largely due to recurrence and aggressive metastasis of the disease. In this study, we examined the potential of exosomal miRNAs as biomarkers of recurrent lung cancer. Initially, in vitro miRNA profiles of normal lung (Beas-2b) and lung cancer (H1299) cells and of exosomes isolated from conditioned media were determined. In vivo study involved establishing subcutaneous primary and recurrent lung cancer xenografts in nude mouse model and examining tumor and serum exosomal miRNA alteration in secondary/recurrent lung tumors. A total of 77 miRNAs were observed to be significantly modulated in the H1299 cells (47 miRNA upregulated and 30 downregulated) compared to the Beas-2b cells. The exosomes isolated from conditioned media indicated several miRNAs which were in agreement with cells of origin. A similarity was also observed between miRNAs from serum exosomes and tumors, indicating their origin from the lung tumors. Two miRNAs, miR-21 and miR-155, were found to be significantly upregulated in recurrent tumors compared to primary tumors. These miRNAs were also upregulated in serum exosomes of recurrent tumor-bearing animals versus non-tumor- or primary tumor-bearing animals. Increased expression of the recurrent disease markers were also observed in recurrent tumors compared with primary tumors. Serum exosomes from recurrent tumor mice mirrored its tumor profile in expressing higher levels of these proteins compared with exosomes from primary tumor mice. Our data suggest that exosomal miRNA signatures may be a true representation of a pathological profile of lung cancer; thus, miRNAs could serve as promising biomarkers for non-invasive diagnosis of the disease.

Exosomes: potential for early detection in pancreatic cancer

Progress in the treatment of patients with pancreatic cancer at earlier stages has motivated research in identifying novel noninvasive or minimally invasive biomarkers for early detection. Exosomes, which contain bioactive molecules (such as proteins, RNAs and lipids), are membrane-structured nanovesicles that are secreted from living cells and are found in human body fluids. As functional mediators, exosomes play key roles in cell-cell communications, regulating diverse biological processes. Here we aim to examine recent findings in the potential diagnostic value of serum exosomes in pancreatic cancer.

Tumour exosomes display differential mechanical and complement activation properties dependent on malignant state: implications in endothelial leakiness

Background

Exosomes have been implicated in tumour progression and metastatic spread. Little is known of the effect of mechanical and innate immune interactions of malignant cell-derived exosomes on endothelial integrity, which may relate to increased extravasation of circulating tumour cells and, therefore, increased metastatic spread.

Methods

Exosomes isolated from non-malignant immortalized HCV-29 and isogenic malignant non-metastatic T24 and malignant metastatic FL3 bladder cells were characterized by nanoparticle tracking analysis and quantitative nanomechanical mapping atomic force microscopy (QNM AFM) to determine size and nanomechanical properties. Effect of HCV-29, T24 and FL3 exosomes on human umbilical vein endothelial cell (HUVEC) monolayer integrity was determined by transendothelial electrical resistance (TEER) measurements and transport was determined by flow cytometry. Complement activation studies in human serum of malignant and non-malignant cell-derived exosomes were performed.

Results

FL3, T24 and HCV-29 cells produced exosomes at similar concentration per cell (6.64, 6.61 and 6.46×10⁴ exosomes per cell for FL3, T24 and HCV-29 cells, respectively) and of similar size (120.2 nm for FL3, 127.6 nm for T24 and 117.9 nm for HCV-29, respectively). T24 and FL3 cell-derived exosomes exhibited a markedly reduced stiffness, 95 MPa and 280 MPa, respectively, compared with 1,527 MPa with non-malignant HCV-29 cell-derived exosomes determined by QNM AFM. FL3 and T24 exosomes induced endothelial disruption as measured by a decrease in TEER in HUVEC monolayers, whereas no effect was observed for HCV-29 derived exosomes. FL3 and T24 exosomes traffic more readily (11.6 and 21.4% of applied exosomes, respectively) across HUVEC monolayers than HCV-29 derived exosomes (7.2% of applied exosomes). Malignant cell-derived exosomes activated complement through calcium-sensitive pathways in a concentration-dependent manner.

Conclusions

Malignant (metastatic and non-metastatic) cell line exosomes display a markedly reduced stiffness and adhesion but an increased complement activation compared to non-malignant cell line exosomes, which may explain the observed increased endothelial monolayer disruption and transendothelial transport of these vesicles.

Serum levels of unique miR-551-5p and endothelial-specific miR-126a-5p allow discrimination of patients in the early phase of acute pancreatitis

OBJECTIVES

Vascular dysfunction is a severe complication which can cause organ ischemia and damage during acute pancreatitis (AP). Laboratory assessment of AP is based on several routine parameters and does not reflect endothelial dysfunction or organ injury. Recently, small non-protein-coding RNAs (miRNAs) have been introduced to laboratory diagnostics as new biomarkers or predictive parameters. Candidate miRNAs (hsa-miR-16-5p, -103a-3p, -122-5p, -126-5p, -148a-5p, -216a-5p, -375, and -551b-5b) were selected to check their possible clinical application in stratification of patients with different AP severity.

METHODS

In this observational study, 62 patients with mild (MAP) and 26 with moderate and severe (SAP) acute pancreatitis were included. The control group consisted of 10 age and sex matched subjects. Circulating miRNAs were analyzed in serum using a quantitative real-time PCR method (q-RT-PCR) by means of 3'-locked-nucleic-acid primers.

RESULTS

In SAP patients, a significant increase in most of the selected miRNAs (miR-126-5p, -148a-3p, -216a-5p and -551b-5p, and miR-375) was observed when compared to control subjects. In MAP patients, three miRNAs were significantly elevated: endothelial-specific miR-216a-5p, -551b-5p, as well as miR-375 that is highly abundant in pancreas. ROC analysis revealed that miR-126-p and miR-551b-5p can predict AP severity (AUC 0.748, sensitivity 60.0%, specificity 87.1%, p < 0.001) and (AUC 0.716; sensitivity 69.2%, specificity 72.6%, p < 0.001). miR-375 was not relevant (AUC 0.458; sensitivity 55.%, specificity 44.4%).

CONCLUSIONS

A pancreatic miRNA signature can be useful for assessment of pancreatic injury in the acute phase of AP. Endothelial dysfunction during AP is reflected by levels of specific circulating miRNAs and may help in patient stratification.

Exosomes Biogenesis and Potentials in Disease Diagnosis and Drug Delivery

Exosomes were discovered more than 30 years ago. Only recently has their importance been recognized for intercellular communication. Exosomes, with their size ranging from 30 nm to 100 nm, are lipid bilayer nanoparticles and secreted by many different types of cells with versatile functions. Exosomes contain macromolecules and exist in various body fluids, including blood, urine, milk and ascites fluid. Due to their specific property, exosomes are very promising in the fields of disease diagnosis and therapy. Nanotechnology is a great tool that will be helpful in basic research and the application of exosomes. Here, we briefly review the function and potential use of exosomes in nanomedicine.

The fusion of two worlds: non-coding RNAs and extracellular vesicles--diagnostic and therapeutic implications (Review)

The role of the extracellular non-coding RNAs, particularly microRNAs present in tumor-derived extravesicles, has been intensively exploited in human cancer as a promising tool for diagnostic and prognostic purposes. Current knowledge on exosomes shows an important role not only as vehicles in the intercellular communication, but the transfer of their content can specifically modulate the surrounding microenvironment, leading to tumor development and progression and affecting therapy response. Based on this, much effort has focused on understanding the mechanisms behind the biology of exosomes and their closely interaction with non-coding RNAs as an efficient tool in tumor diagnostic and therapy. Here we summarize the current knowledge on extracellular and exosomes-enclosed non-coding RNAs, and their importance as potential biomarkers and mediators of intercellular communication in tumor biology.

Diagnostic and therapeutic potentials of exosomes in CNS diseases

A newly discovered cell-to-cell communication system involves small, membrane-enveloped nanovesicles, called exosomes. We describe here how these extracellular nanoparticles were discovered and how it became gradually apparent that they play fundamental roles in regulation of physiological functions and pathological processes. Exosomes enable intercellular communication by transporting genetic material, proteins and lipids to cells in their vicinity or at distant sites, and subsequently regulating functions of targeted cells. Relatively recent experiments indicate that exosomes are released also by CNS cells, including cortical and hippocampal neurons, glial cells, astrocytes and oligodendrocytes, and that exosomes have significant impact on pathophysiology of the brain. How it is decided what individual exosomes will carry to their targets is not understood, but it appears that the contents may represent "signature cargos" that are characteristic for various conditions. Exploration of such characteristics could result in discovery of novel diagnostic biomarkers. Exosomes are also promising as a vehicle for therapeutic delivery of micro RNA or other compounds. How to deliver exosomes to selected sites has been a tantalizing question. Recent experiments revealed that at least some exosomes carry antibodies on their surface, suggesting that it may be feasible to deliver exosomes to unique sites based on the recognition of antigens by those antibodies. This discovery implies that rather precise targeting of both natural and engineered exosomes may be feasible. This would reduce distribution volume of therapeutics, and consequently minimize their side effects. This article is part of a Special Issue entitled Neuroimmunology in Health And Disease.

Antibody-coupled monolithic silica microtips for highthroughput molecular profiling of circulating exosomes

Exosome-mediated signal transportation plays a variety of critical roles in cancer progression and metastasis. From the aspect of cancer diagnosis, circulating exosomes are ideal resources of biomarkers because molecular features of tumor cells are transcribed on them. However, isolating pure exosomes from body fluids is time-consuming and still major challenge to be addressed for comprehensive profiling of exosomal proteins and miRNAs. Here we constructed anti-CD9 antibody-coupled highly porous monolithic silica microtips which allowed automated rapid and reproducible exosome extraction from multiple clinical samples. We applied these tips to explore lung cancer biomarker proteins on exosomes by analyzing 46 serum samples. The mass spectrometric quantification of 1,369 exosomal proteins identified CD91 as a lung adenocarcinoma specific antigen on exosomes, which was further validated with CD9-CD91 exosome sandwich ELISA measuring 212 samples. Our simple device can promote not only biomarker discovery studies but also wide range of omics researches about exosomes.

Colonic miRNA expression/secretion, regulated by intestinal epithelial PepT1, plays an important role in cell-to-cell communication during colitis

PepT1 is a member of the proton-oligopeptide cotransporter family SLC15, which mediates the transport of di/tripeptides from intestinal lumen into epithelial cells. MicroRNAs (miRNAs), a small noncoding RNAs (21–23 nucleotides), post-transcriptionally regulate gene expression by binding to the 3′-untranslated regions (UTRs) of their target mRNAs. Although the role of most miRNAs remains elusive, they have been implicated in vital cellular functions such as intestinal epithelial cells differentiation, proliferation, and apoptosis. In the present study, we investigated the effect of intestinal epithelial PepT1 expression on microRNA (miRNA) expression/secretion in the colons of control mice and in mice with experimentally induced colonic inflammation (colitis). The colonic miRNA expression was deregulated in both colitis and control mice but the deregulation of miRNA expression/secretion was specific to colonic tissue and did not affect other tissues such as spleen and liver. Intestinal epithelial PepT1-dependent deregulation of colonic miRNA expression not only affects epithelial cells but also other cell types, such as intestinal macrophages. Importantly, we found the miRNA 23b which was known to be involved in inflammatory bowel disease was secreted and transported between cells to impose a gene-silencing effect on recipient intestinal macrophages. Based on our data, we may conclude that the expression of a specific protein, PepT1, in the intestine affects local miRNA expression/secretion in the colon on a tissue specific manner and may play an important role during the induction and progression of colitis. Colonic miRNA expression/secretion, regulated by intestinal epithelial PepT1, could play a crucial role in cell-to-cell communication during colitis.

Distinct RNA profiles in subpopulations of extracellular vesicles: apoptotic bodies, microvesicles and exosomes

Introduction

In recent years, there has been an exponential increase in the number of studies aiming to understand the biology of exosomes, as well as other extracellular vesicles. However, classification of membrane vesicles and the appropriate protocols for their isolation are still under intense discussion and investigation. When isolating vesicles, it is crucial to use systems that are able to separate them, to avoid cross-contamination.

Method

EVs released from three different kinds of cell lines: HMC-1, TF-1 and BV-2 were isolated using two centrifugation-based protocols. In protocol 1, apoptotic bodies were collected at 2,000×g, followed by filtering the supernatant through 0.8 µm pores and pelleting of microvesicles at 12,200×g. In protocol 2, apoptotic bodies and microvesicles were collected together at 16,500×g, followed by filtering of the supernatant through 0.2 µm pores and pelleting of exosomes at 120,000×g. Extracellular vesicles were analyzed by transmission electron microscopy, flow cytometry and the RNA profiles were investigated using a Bioanalyzer^®.

Results

RNA profiles showed that ribosomal RNA was primary detectable in apoptotic bodies and smaller RNAs without prominent ribosomal RNA peaks in exosomes. In contrast, microvesicles contained little or no RNA except for microvesicles collected from TF-1 cell cultures. The different vesicle pellets showed highly different distribution of size, shape and electron density with typical apoptotic body, microvesicle and exosome characteristics when analyzed by transmission electron microscopy. Flow cytometry revealed the presence of CD63 and CD81 in all vesicles investigated, as well as CD9 except in the TF-1-derived vesicles, as these cells do not express CD9.

Conclusions

Our results demonstrate that centrifugation-based protocols are simple and fast systems to distinguish subpopulations of extracellular vesicles. Different vesicles show different RNA profiles and morphological characteristics, but they are indistinguishable using CD63-coated beads for flow cytometry analysis.

Intercellular communication by exosome-derived microRNAs in cancer

The development of human cancers is a multistep process in which normal cells acquire characteristics that ultimately lead to their conversion into cancer cells. Many obstacles must be overcome for this process to occur; of these obstacles, is the ability to survive an inhospitable microenvironment. It is recognized that the intercommunication between tumor cells and their surrounding microenvironment is essential to overcoming this obstacle and for the tumor to progress, metastasize and establish itself at distant sites. Exosomes are membrane-derived vesicles that have recently been recognized as important mediators of intercellular communication, as they carry lipids, proteins, mRNAs and microRNAs that can be transferred to a recipient cell via fusion of the exosome with the target cell membrane. In the context of cancer cells, this process entails the transfer of cancer-promoting cellular contents to surrounding cells within the tumor microenvironment or into the circulation to act at distant sites, thereby enabling cancer progression. In this process, the transfer of exosomal microRNAs to a recipient cell where they can regulate target gene expression is of particular interest, both in understanding the basic biology of cancer progression and for the development of therapeutic approaches. This review discusses the exosome-mediated intercellular communication via microRNAs within the tumor microenvironment in human cancers, with a particular focus on breast cancer exosomes.