Biodistribution and function of extracellular miRNA-155 in mice. Sci Rep. 2015;5:10721. [PMID: 26024046 PMCID: PMC4448655 DOI: 10.1038/srep10721]

The role of exosome-shuttled miRNAs in heavy metal-induced peripheral tissues and neuroinflammation in Alzheimer's disease

Heavy metal-induced neuroinflammation is a significant pathophysiologic mechanism in Alzheimer's disease (AD). Microglia-mediated neuroinflammation plays a crucial role in the pathogenesis of AD. Multiple miRNAs are differentially expressed in peripheral tissues after heavy metal exposure, and increasing evidence suggests that they are involved in AD progression by regulating microglial homeostasis. Exosomes, which are capable of loading miRNAs and crossing the bloodbrain barrier, serve as mediators of communication between peripheral tissues and the brain. In this review, we summarize the current evidence on the link between miRNAs in peripheral tissues and neuroinflammation in AD after heavy metal exposure and propose a role for miRNAs in the microglial neurodegenerative phenotype (MGnD) of AD. This study will help to elucidate the link between peripheral tissue damage and MGnD-mediated neuroinflammation in AD after heavy metal exposure. Additionally, we summarize the regulatory effects of natural compounds on peripheral tissue-derived miRNAs, which could be potential therapeutic targets for natural compounds to regulate peripheral tissue-derived exosomal miRNAs to ameliorate heavy metal-induced MGnD-mediated neuroinflammation in patients with AD after heavy metal exposure.

Evaluation of unmodified human cell-derived extracellular vesicle mitochondrial deoxyribonucleic acid-based biodistribution in rodents

Recently, extracellular vesicles (EVs) have been developed as therapeutic targets for various diseases. Biodistribution is crucial for EVs intended for therapeutic purposes because it can determine the degree of on- and off-target effects. This study aimed to explore techniques to evaluate the biodistribution of unmodified EVs. We devised a novel quantitative polymerase chain reaction (qPCR)-based assay to detect unmodified EVs by targeting mitochondrial deoxyribonucleic acid (mtDNA), a constituent of EVs. We focused on specific mtDNA regions that exhibited homologous variations distinct from their rodent mtDNA counterparts to establish this analytical approach. Herein, we successfully designed primers and probes targeting human and rodent mtDNA sequences and developed a highly specific and sensitive qPCR method. Furthermore, the quantification range of EVs isolated from various cells differed based on the manufacturer and cell source. IRDye 800CW-labelled Expi293F EV mimetics were administered to the animals via the tail vein to compare the imaging test and mtDNA-qPCR results. The results obtained from imaging tests and mtDNA-qPCR to investigate EV biodistribution patterns revealed differences. The results revealed that our newly developed method effectively determined the biodistribution of unmodified EVs with high sensitivity and reproducibility.

Small extracellular vesicles (sEVs)-based gene delivery platform for cell-specific CRISPR/Cas9 genome editing

Small extracellular vesicles (sEVs) are naturally occurring vesicles that have the potential to be manipulated to become promising drug delivery vehicles for on-demand in vitro and in vivo gene editing. Here, we developed the modular safeEXO platform, a prototype sEV delivery vehicle that is mostly devoid of endogenous RNA and can efficaciously deliver RNA and ribonucleoprotein (RNP) complexes to their intended intracellular targets manifested by downstream biologic activity. We also successfully engineered producer cells to produce safeEXO vehicles that contain endogenous Cas9 (safeEXO-CAS) to effectively deliver efficient ribonucleoprotein (RNP)-mediated CRISPR genome editing machinery to organs or diseased cells in vitro and in vivo. We confirmed that safeEXO-CAS sEVs could co-deliver ssDNA, sgRNA and siRNA, and efficaciously mediate gene insertion in a dose-dependent manner. We demonstrated the potential to target safeEXO-CAS sEVs by engineering sEVs to express a tissue-specific moiety, integrin alpha-6 (safeEXO-CAS-ITGA6), which increased their uptake to lung epithelial cells in vitro and in vivo. We tested the ability of safeEXO-CAS-ITGA6 loaded with EMX1 sgRNAs to induce lung-targeted editing in mice, which demonstrated significant gene editing in the lungs with no signs of morbidity or detectable changes in immune cell populations. Our results demonstrate that our modular safeEXO platform represents a targetable, safe, and efficacious vehicle to deliver nucleic acid-based therapeutics that successfully reach their intracellular targets. Furthermore, safeEXO producer cells can be genetically manipulated to produce safeEXO vehicles containing CRISPR machinery for more efficient RNP-mediated genome editing. This platform has the potential to improve current therapies and increase the landscape of treatment for various human diseases using RNAi and CRISPR approaches.

Prospective applications of extracellular vesicle-based therapies in regenerative medicine: implications for the use of dental stem cell-derived extracellular vesicles

In the 21st century, research on extracellular vesicles (EVs) has made remarkable advancements. Recently, researchers have uncovered the exceptional biological features of EVs, highlighting their prospective use as therapeutic targets, biomarkers, innovative drug delivery systems, and standalone therapeutic agents. Currently, mesenchymal stem cells stand out as the most potent source of EVs for clinical applications in tissue engineering and regenerative medicine. Owing to their accessibility and capability of undergoing numerous differentiation inductions, dental stem cell-derived EVs (DSC-EVs) offer distinct advantages in the field of tissue regeneration. Nonetheless, it is essential to note that unmodified EVs are currently unsuitable for use in the majority of clinical therapeutic scenarios. Considering the high feasibility of engineering EVs, it is imperative to modify these EVs to facilitate the swift translation of theoretical knowledge into clinical practice. The review succinctly presents the known biotherapeutic effects of odontogenic EVs and the underlying mechanisms. Subsequently, the current state of functional cargo loading for engineered EVs is critically discussed. For enhancing EV targeting and in vivo circulation time, the review highlights cutting-edge engineering solutions that may help overcome key obstacles in the clinical application of EV therapeutics. By presenting innovative concepts and strategies, this review aims to pave the way for the adaptation of DSC-EVs in regenerative medicine within clinical settings.

Studying exogenous extracellular vesicle biodistribution by in vivo fluorescence microscopy

Extracellular vesicles (EVs) are lipid-bound vesicles released from cells that play a crucial role in many physiological processes and pathological mechanisms. As such, there is great interest in their biodistribution. One currently accessible technology to study their fate in vivo involves fluorescent labelling of exogenous EVs followed by whole-animal imaging. Although this is not a new technology, its translation from studying the fate of whole cells to subcellular EVs requires adaptation of the labelling techniques, excess dye removal and a refined experimental design. In this Review, we detail the methods and considerations for using fluorescence in vivo and ex vivo imaging to study the biodistribution of exogenous EVs and their roles in physiology and disease biology.

Extracellular Vesicles in Hepatobiliary Health and Disease

Extracellular vesicles (EVs) are membrane-bound nanoparticles released by cells and are an important means of intercellular communication in physiological and pathological states. We provide an overview of recent advances in the understanding of EV biogenesis, cargo selection, recipient cell effects, and key considerations in isolation and characterization techniques. Studies on the physiological role of EVs have relied on cell-based model systems due to technical limitations of studying endogenous nanoparticles in vivo . Several recent studies have elucidated the mechanistic role of EVs in liver diseases, including nonalcoholic fatty liver disease, viral hepatitis, cholestatic liver disease, alcohol-associated liver disease, acute liver injury, and liver cancers. Employing disease models and human samples, the biogenesis of lipotoxic EVs downstream of endoplasmic reticulum stress and microvesicles via intracellular activation stress signaling are discussed in detail. The diverse cargoes of EVs including proteins, lipids, and nucleic acids can be enriched in a disease-specific manner. By carrying diverse cargo, EVs can directly confer pathogenic potential, for example, recruitment and activation of monocyte-derived macrophages in NASH and tumorigenicity and chemoresistance in hepatocellular carcinoma. We discuss the pathogenic role of EVs cargoes and the signaling pathways activated by EVs in recipient cells. We review the literature that EVs can serve as biomarkers in hepatobiliary diseases. Further, we describe novel approaches to engineer EVs to deliver regulatory signals to specific cell types, and thus use them as therapeutic shuttles in liver diseases. Lastly, we identify key lacunae and future directions in this promising field of discovery and development. © 2023 American Physiological Society. Compr Physiol 13:4631-4658, 2023.

Role of Extracellular Vesicles in Liver Diseases

Extracellular vesicles (EVs) are cell-derived membrane structures that are formed by budding from the plasma membrane or originate from the endosomal system. These microparticles (100 nm-100 µm) or nanoparticles (>100 nm) can transport complex cargos to other cells and, thus, provide communication and intercellular regulation. Various cells, such as hepatocytes, liver sinusoidal endothelial cells (LSECs) or hepatic stellate cells (HSCs), secrete and take up EVs in the healthy liver, and the amount, size and content of these vesicles are markedly altered under pathophysiological conditions. A comprehensive knowledge of the modified EV-related processes is very important, as they are of great value as biomarkers or therapeutic targets. In this review, we summarize the latest knowledge on hepatic EVs and the role they play in the homeostatic processes in the healthy liver. In addition, we discuss the characteristic changes of EVs and their potential exacerbating or ameliorating effects in certain liver diseases, such as non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease (AFLD), drug induced liver injury (DILI), autoimmune hepatitis (AIH), hepatocarcinoma (HCC) and viral hepatitis.

Bioengineered Mesenchymal-Stromal-Cell-Derived Extracellular Vesicles as an Improved Drug Delivery System: Methods and Applications

Extracellular vesicles (EVs) are cell-derived nano-sized lipid membranous structures that modulate cell-cell communication by transporting a variety of biologically active cellular components. The potential of EVs in delivering functional cargos to targeted cells, their capacity to cross biological barriers, as well as their high modification flexibility, make them promising drug delivery vehicles for cell-free therapies. Mesenchymal stromal cells (MSCs) are known for their great paracrine trophic activity, which is largely sustained by the secretion of EVs. MSC-derived EVs (MSC-EVs) retain important features of the parental cells and can be bioengineered to improve their therapeutic payload and target specificity, demonstrating increased therapeutic potential in numerous pre-clinical animal models, including in the treatment of cancer and several degenerative diseases. Here, we review the fundamentals of EV biology and the bioengineering strategies currently available to maximize the therapeutic value of EVs, focusing on their cargo and surface manipulation. Then, a comprehensive overview of the methods and applications of bioengineered MSC-EVs is presented, while discussing the technical hurdles yet to be addressed before their clinical translation as therapeutic agents.

The biodistribution of placental and fetal extracellular vesicles during pregnancy following placentation

Human pregnancy is a highly orchestrated process requiring extensive cross-talk between the mother and the fetus. Extracellular vesicles released by the fetal tissue, particularly the placenta, are recognized as important mediators of this process. More recently, the importance of placental extracellular vesicle biodistribution studies in animal models has received increasing attention as identifying the organs to which extracellular vesicles are targeted to helps us understand more about this communication system. Placental extracellular vesicles are categorized based on their size into macro-, large-, and small-extracellular vesicles, and their biodistribution is dependent on the extracellular vesicle's particle size, the direction of blood flow, the recirculation of blood, as well as the retention capacity in organs. Macro-extracellular vesicles are exclusively localized to the lungs, while large- and small-extracellular vesicles show high levels of distribution to the lungs and liver, while there is inconsistency in the reporting of distribution to the spleen and kidneys. This inconsistency may be due to the differences in the methodologies employed between studies and their limitations. Future studies should incorporate analysis of placental extracellular vesicle biodistribution at the macroscopic level on whole animals and organs/tissues, as well as the microscopic cellular level.

The role of miR-155 on liver diseases by modulating immunity, inflammation and tumorigenesis

The liver is a well-known metabolic organ that can be susceptible to external stimuli to affect its normal physiological function. Worldwide, the morbidity and mortality of liver diseases are skyrocketing every year, causing human health crises. Recently, new approaches such as biotechnology have been introduced to achieve optimal treatment and prognostic management of liver diseases. microRNAs (miRNAs), a kind of small non-coding RNA molecule, have the advantages of biodiversity, wide distribution and numerous members. Among these miRNAs, miR-155 is an important regulator of inflammation, immunity and tumorigenesis. In this review, the PubMed and Web of Science databases were searched from 2009 to 2022. After inclusion and exclusion, 64 articles were selected for a systematic review to comprehensively summarize the mechanisms of miR-155 regulating inflammation, immunity and tumorigenesis in liver diseases and liver cancer, covering in vitro, in vivo and clinical studies. Existing preclinical studies and clinical trials have listed that the up-regulation and down-regulation of miR-155 are significant in alcoholic liver injury, viral hepatitis, autoimmune hepatitis, infectious liver injury, liver transplantation and liver cancer. The immune and inflammation effects of miR-155 are manifested by regulating macrophage polarization, NK cell killing, Th17 cell and Th1/Th2 cell differentiation. Additionally, miR-155 is also committed to participating in the cell cycle, invasion and metastasis, immune escape and other processes to promote and intensify the development of liver cancer. In conclusion, miR-155 is not only a biomarker for the diagnosis and prognosis of liver diseases, but also plays a therapeutic role via regulating immunity, inflammation and tumorigenesis.

Emerging Biomarkers in Alcohol-associated Hepatitis

Alcohol-associated hepatitis (AH) is a clinical syndrome of jaundice, abdominal pain, and anorexia due to prolonged heavy alcohol intake. AH is associated with changes in gene expression, cytokines, immune response, and the gut microbiome. There are limited biomarkers to diagnose and prognosticate in AH, but several non-invasive biomarkers are emerging. In this review, clinical risk-stratifying algorithms, promising AH biomarkers like cytokeratin-18 fragments, genetic polymorphisms, and microRNAs will be reviewed.

Tracking tools of extracellular vesicles for biomedical research

Imaging of extracellular vesicles (EVs) will facilitate a better understanding of their biological functions and their potential as therapeutics and drug delivery vehicles. In order to clarify EV-mediated cellular communication in vitro and to track the bio-distribution of EV in vivo, various strategies have been developed to label and image EVs. In this review, we summarized recent advances in the tracking of EVs, demonstrating the methods for labeling and imaging of EVs, in which the labeling methods include direct and indirect labeling and the imaging modalities include fluorescent imaging, bioluminescent imaging, nuclear imaging, and nanoparticle-assisted imaging. These techniques help us better understand the mechanism of uptake, the bio-distribution, and the function of EVs. More importantly, we can evaluate the pharmacokinetic properties of EVs, which will help promote their further clinical application.

Strategies to overcome the main challenges of the use of exosomes as drug carrier for cancer therapy

Exosomes are naturally occurring nanosized particles that aid intercellular communication by transmitting biological information between cells. Exosomes have therapeutic efficacy that can transfer their contents between cells as natural carriers. In addition, the exosomal contents delivered to the recipient pathological cells significantly inhibit cancer progression. However, exosome-based tumor treatments are inadequately precise or successful, and various challenges should be adequately overcome. Here, we discuss the significant challenges that exosomes face as drug carriers used for therapeutic targets and strategies for overcoming these challenges in order to promote this new incoming drug carrier further and improve future clinical outcomes. We also present techniques for overcoming these challenges.

The Implications of Noncoding RNAs in the Evolution and Progression of Nonalcoholic Fatty Liver Disease (NAFLD)-Related HCC

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver pathology worldwide. Meanwhile, liver cancer represents the sixth most common malignancy, with hepatocellular carcinoma (HCC) as the primary, most prevalent subtype. Due to the rising incidence of metabolic disorders, NAFLD has become one of the main contributing factors to HCC development. However, although NAFLD might account for about a fourth of HCC cases, there is currently a significant gap in HCC surveillance protocols regarding noncirrhotic NAFLD patients, so the majority of NAFLD-related HCC cases were diagnosed in late stages when survival chances are minimal. However, in the past decade, the focus in cancer genomics has shifted towards the noncoding part of the genome, especially on the microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), which have proved to be involved in the regulation of several malignant processes. This review aims to summarize the current knowledge regarding some of the main dysregulated, noncoding RNAs (ncRNAs) and their implications for NAFLD and HCC development. A central focus of the review is on miRNA and lncRNAs that can influence the progression of NAFLD towards HCC and how they can be used as potential screening tools and future therapeutic targets.

The emerging roles of extracellular vesicles as intercellular messengers in liver physiology and pathology

Extracellular vesicles (EVs) are membrane-enclosed particles released from almost all cell types. EVs mediate intercellular communication by delivering their surface and luminal cargoes, including nucleic acids, proteins, and lipids, which reflect the pathophysiological conditions of their cellular origins. Hepatocytes and hepatic non-parenchymal cells utilize EVs to regulate a wide spectrum of biological events inside the liver and transfer them to distant organs through systemic circulation. The liver also receives EVs from multiple organs and integrates these extrahepatic signals that participate in pathophysiological processes. EVs have recently attracted growing attention for their crucial roles in maintaining and regulating hepatic homeostasis. This review summarizes the roles of EVs in intrahepatic and interorgan communications under different pathophysiological conditions of the liver, with a focus on chronic liver diseases including nonalcoholic steatohepatitis, alcoholic hepatitis, viral hepatitis, liver fibrosis, and hepatocellular carcinoma. This review also discusses recent progress for potential therapeutic applications of EVs by targeting or enhancing EV-mediated cellular communication for the treatment of liver diseases.

Roles of small extracellular vesicles in the development, diagnosis and possible treatment strategies for hepatocellular carcinoma (Review)

Hepatocellular carcinoma (HCC) is the most common malignancy of hepatocytes accounting for 75-85% of primary hepatic carcinoma cases. Small extracellular vesicles (sEVs), previously known as exosomes with a diameter of 30-200 nm, can transport a variety of biological molecules between cells, and have been proposed to function in physiological and pathological processes. Recent studies have indicated that the cargos of sEVs are implicated in intercellular crosstalk among HCC cells, paratumor cells and the tumor microenvironment. sEV-encapsulated substances (including DNA, RNA, proteins and lipids) regulate signal transduction pathways in recipient cells and contribute to cancer initiation and progression in HCC. In addition, the differential expression of sEV cargos between patients facilitates the potential utility of sEVs in the diagnosis and prognosis of patients with HCC. Furthermore, the intrinsic properties of low immunogenicity and high stability render sEVs ideal vehicles for targeted drug delivery in the treatment of HCC. The present review article summarizes the carcinogenic and anti-neoplastic capacities of sEVs and discusses the potential and prospective diagnostic and therapeutic applications of sEVs in HCC.

Nano-Messengers of the Heart: Promising Theranostic Candidates for Cardiovascular Maladies

Till date, cardiovascular diseases remain a leading cause of morbidity and mortality across the globe. Several commonly used treatment methods are unable to offer safety from future complications and longevity to the patients. Therefore, better and more effective treatment measures are needed. A potential cutting-edge technology comprises stem cell-derived exosomes. These nanobodies secreted by cells are intended to transfer molecular cargo to other cells for the establishment of intercellular communication and homeostasis. They carry DNA, RNA, lipids, and proteins; many of these molecules are of diagnostic and therapeutic potential. Several stem cell exosomal derivatives have been found to mimic the cardioprotective attributes of their parent stem cells, thus holding the potential to act analogous to stem cell therapies. Their translational value remains high as they have minimal immunogenicity, toxicity, and teratogenicity. The current review highlights the potential of various stem cell exosomes in cardiac repair, emphasizing the recent advancements made in the development of cell-free therapeutics, particularly as biomarkers and as carriers of therapeutic molecules. With the use of genetic engineering and biomimetics, the field of exosome research for heart treatment is expected to solve various theranostic requirements in the field paving its way to the clinics.

Stem cell membrane, stem cell-derived exosomes and hybrid stem cell camouflaged nanoparticles: A promising biomimetic nanoplatforms for cancer theranostics

Nanomedicine research has advanced dramatically in recent decades. Nonetheless, traditional nanomedicine faces significant obstacles such as the low concentration of the drug at target sites and accelerated removal of the drug from blood circulation. Various techniques of nanotechnology, including cell membrane coating, have been developed to address these challenges and to improve targeted distribution and redcue cell membrane-mediated immunogenicity. Recently, stem cell (SC) membranes, owing to their immunosuppressive and regenerative properties, have grabbed attention as attractive therapeutic carriers for targeting specific tissues or organs. Bioengineering strategies that combine synthetic nanoparticles (NPs) with SC membranes, because of their homing potential and tumor tropism, have recently received a lot of publicity. Several laboratory experiments and clinical trials have indicated that the benefits of SC-based technologies are mostly related to the effects of SC-derived exosomes (SC-Exos). Exosomes are known as nano-sized extracellular vehicles (EVs) that deliver particular bioactive molecules for cell-to-cell communication. In this regard, SC-derived exosome membranes have recently been employed to improve the therapeutic capability of engineered drug delivery vehicles. Most recently, for further enhancing NPs' functionality, a new coating approach has been offered that combines membranes from two separate cells. These hybrid membrane delivery vehicles have paved the way for the development of biocompatible, high-efficiency, biomimetic NPs with varying hybrid capabilities that can overcome the drawbacks of present NP-based treatment techniques. This review explores stem cell membranes, SC-Exos, and hybrid SC-camouflaged NPs preparation methods and their importance in cancer therapy.

Clinical implications of exosome-derived noncoding RNAs in liver

Exosomes, one of three main types of extracellular vesicles, are ~30-100 nm in diameter and have a lipid bilayer membrane. They are widely distributed in almost all body fluids. Exosomes have the potential to regulate unknown cellular and molecular mechanisms in intercellular communication, organ homeostasis, and diseases. They are critical signal carriers that transfer nucleic acids, proteins, lipids, and other substances into recipient cells, participating in cellular signal transduction and material exchange. ncRNAs are non-protein-coding genes that account for over 90% of the genome and include microRNAs (miRNAs), long ncRNAs (lncRNAs), and circular RNAs (circRNAs). ncRNAs are crucial for physiological and pathological activities in the liver by participating in gene transcription, posttranscriptional epigenetic regulation, and cellular processes through interacting with DNA, RNA, or proteins. Recent evidence from both clinical and preclinical studies indicates that exosome-derived noncoding RNAs (ncRNAs) are highly involved in the progression of acute and chronic liver diseases by regulating hepatic lipid metabolism, innate immunity, viral infection, fibrosis, and cancer. Therefore, exosome-derived ncRNAs have promising potential and clinical implications for the early diagnosis, targeted therapy, and prognosis of liver diseases.

miR-155: A Potential Biomarker for Predicting Mortality in COVID-19 Patients

COVID-19, a pandemic of severe acute respiratory syndrome caused by Coronavirus 2 (SARS-CoV-2), continues to pose diagnostic and therapeutic challenges due to its unpredictable clinical course. Prognostic biomarkers may improve care by enabling quick identification of patients who can be safely discharged home versus those who may need careful respiratory monitoring and support. MicroRNAs (miRNAs) have risen to prominence as biomarkers for many disease states and as tools to assist in medical decisions. In the present study, we aimed to examine circulating miRNAs in hospitalized COVID-19 patients and to explore their potential as biomarkers for disease severity. We studied, by quantitative PCR, the expressions of miR-21, miR-146a, miR-146b, miR-155, and miR-499 in peripheral blood. We found that mild COVID-19 patients had 2.5-fold less circulating miR-155 than healthy people, and patients with a severe COVID-19 disease had 5-fold less circulating miR-155 than healthy people. In addition, we found that miR-155 is a good predictor of COVID-19 mortality. We suggest that examining miR-155 levels in patients' blood, upon admission to hospital, will ameliorate the care given to COVID-19 patients.

Alcohol Promotes Exosome Biogenesis and Release via Modulating Rabs and miR-192 Expression in Human Hepatocytes

Exosomes are membrane vesicles released by various cell types into the extracellular space under different conditions including alcohol exposure. Exosomes are involved in intercellular communication and as mediators of various diseases. Alcohol use causes oxidative stress that promotes exosome secretion. Here, we elucidated the effects of alcohol on exosome biogenesis and secretion using human hepatocytes. We found that alcohol treatment induces the expression of genes involved in various steps of exosome formation. Expression of Rab proteins such as Rab1a, Rab5c, Rab6, Rab10, Rab11, Rab27a and Rab35 were increased at the mRNA level in primary human hepatocytes after alcohol treatment. Rab5, Rab6 and Rab11 showed significant induction in the livers of patients with alcohol-associated liver disease. Further, alcohol treatment also led to the induction of syntenin, vesicle-associated membrane proteins (VAMPs), and syntaxin that all play various roles in exosome biogenesis and secretion. VAMP3, VAMP5, VAPb, and syntaxin16 mRNA transcripts were increased in alcohol treated cells and in the livers of alcohol-associated liver disease (ALD) patients. Induction in these genes was associated with increases in exosome secretion in alcohol treated hepatocytes. We found that hepatocyte enriched miR-192 and miR-122 levels were significantly decreased in alcohol treated hepatocytes whereas their levels were increased in the cell-free supernatant. The primary transcripts of miR-192 and miR-122 were reduced in alcohol treated hepatocytes, suggesting alcohol partially affects these miRNAs at the transcriptional level. We found that miR-192 has putative binding sites for genes involved in exosome secretion. Inhibition of miR-192 in human hepatoma cells caused a significant increase in Rab27a, Rab35, syntaxin7 and syntaxin16 and a concurrent increase in exosome secretion, suggesting miR-192 regulates exosomes release in hepatocytes. Collectively, our results reveal that alcohol modulates Rabs, VAMPs and syntaxins directly and partly via miR-192 to induce exosome machinery and release.

Biodistribution of unmodified cardiosphere-derived cell extracellular vesicles using single RNA tracing

Extracellular vesicles (EVs) are potent signalling mediators. Although interest in EV translation is ever-increasing, development efforts are hampered by the inability to reliably assess the uptake of EVs and their RNA cargo. Here, we establish a novel qPCR-based method for the detection of unmodified EVS using an RNA Tracer (DUST). In this proof-of-concept study we use a human-specific Y RNA-derived small RNA (YsRNA) we dub "NT4" that is enriched in cardiosphere-derived cell small EVs (CDC-sEVs). The assay is robust, sensitive, and reproducible. Intravenously administered CDC-sEVs accumulated primarily in the heart on a per mg basis. Cardiac injury enhanced EV uptake in the heart, liver, and brain. Inhibition of EV docking by heparin suppressed uptake variably, while inhibition of endocytosis attenuated uptake in all organs. In vitro, EVs were uptaken more efficiently by macrophages, endothelial cells, and cardiac fibroblasts compared to cardiomyocytes. These findings demonstrate the utility of DUST to assess uptake of EVs in vivo and in vitro.

Diverse roles of EV-RNA in cancer progression

Extracellular vesicles (EVs) have emerged as important players in all aspects of cancer biology. Their function is mediated by their cargo and surface molecules including proteins, lipids, sugars and nucleic acids. RNA in particular is a key mediator of EV function both in normal and cancer cells. This statement is supported by several lines of evidence. First, cells do not always randomly load RNA in EVs, there seems to be a specific manner in which cells populate their EVs with certain RNA molecules. Moreover, cellular uptake of EV-RNA and the secondary compartmentalization of EV-RNA in recipient cells is widely reported, and these RNAs have an impact on all aspects of cancer growth and the anti-tumoral immune response. Additionally, EV-RNA seems to work through various mechanisms of action, highlighting the intricacies of EVs and their RNA cargo as prominent means of inter-cellular communication.

Current and Future Biomarkers in Alcoholic Hepatitis

Alcoholic hepatitis (AH) is a clinical syndrome of jaundice, abdominal pain, and anorexia due to prolonged heavy alcohol intake, and is associated with alterations in gene expression, cytokines, immune response, and the gut microbiome. Currently, we have limited biomarkers to diagnose and prognosticate in AH, but there are many novel noninvasive biomarkers under development. We evaluate the currently used algorithms to risk-stratify in AH (such as the Maddrey modified discriminant function), and discuss novel biomarkers in development, such as breath biomarkers, microRNAs, cytokeratin-18 fragments, and the AshTest. We also review the characteristics of an ideal biomarker in AH.

Illuminating RNA trafficking and functional delivery by extracellular vesicles

RNA-based therapeutics are highly promising for the treatment of numerous diseases, by their ability to tackle the genetic origin in multiple possible ways. RNA molecules are, however, incapable of crossing cell membranes, hence a safe and efficient delivery vehicle is pivotal. Extracellular vesicles (EVs) are endogenously derived nano-sized particles and possess several characteristics which make them excellent candidates as therapeutic RNA delivery agent. This includes the inherent capability to functionally transfer RNAs in a selective manner and an enhanced safety profile compared to synthetic particles. Nonetheless, the fundamental mechanisms underlying this selective inter- and intracellular trafficking and functional transfer of RNAs by EVs are poorly understood. Improving our understanding of these systems is a key element of working towards an EV-based or EV-mimicking system for the functional delivery of therapeutic RNA. In this review, state-of-the-art approaches to detect and visualize RNA in situ and in live cells are discussed, as well as strategies to assess functional RNA transfer, highlighting their potential in studying EV-RNA trafficking mechanisms.

Circulating microRNAs after a 24-h ultramarathon run in relation to muscle damage markers in elite athletes

Ultra-endurance sports are growing in popularity but can be associated with adverse health effects, such as exercise-induced muscle damage (EIMD), which can lead to exertional rhabdomyolysis. Circulating microRNAs (miRNAs) may be useful to approach the degree of EIMD. We aimed to (1) investigate the relevance of circulating miRNAs as biomarkers of muscle damage and (2) examine the acute response of skeletal/cardiac muscle and kidney biomarkers to a 24-h run in elite athletes. Eleven elite athletes participated in the 24-h run World Championships. Counter-movement jump (CMJ), creatine kinase (CK), myoglobin (Mb), creatinine (Cr), high-sensitive cardiac troponin T (hs-cTnT), and muscle-specific miRNA (myomiR) levels were measured before, immediately after, and 24 and 48h after the race. CMJ height was reduced immediately after the race (-84.0 ± 25.2%, p < 0.001) and remained low at 24 h (-43.6 ± 20.4%, p = 0.002). We observed high CK activity (53 239 ± 63 608 U/L, p < 0.001) immediately after the race, and it remained elevated 24h after (p < 0.01). Circulating myomiR levels (miR-1-3p, miR-133a-3p, miR-133b, miR-208a-3p, miR-208b-3p, and miR-499a-5p) were elevated immediately after the 24-h run (fold changes: 18-124,723, p<0.001) and significantly (p < 0.05) correlated or tended to significantly (p < 0.07) correlate with the reduction in CMJ height at 24 h. We found no significant correlation between CMJ height loss at 24 h and CK (p = 0.23) or Mb (p = 0.41) values. All elite ultramarathon runners included in our study were diagnosed with exertional rhabdomyolysis after the 24-h ultramarathon race. MyomiR levels may be useful to approach the degree of muscle damage.

Tagged extracellular vesicles with the RBD of the viral spike protein for delivery of antiviral agents against SARS-COV-2 infection

The worldwide spread of COVID-19 highlights the urgent need for an efficient approach to rapidly develop therapeutics and prophylactics against SARS-CoV-2. Extracellular vesicle(EVs) are recognized and endocytosed by tissue cells via specific interactions between surface membrane proteins, where after they deliver their molecular cargo. This provides the potential to modify membrane proteins at EV surfaces as a promising means for specific tissue targeting and drug delivery. In this study, we describe a VSVG viral pseudotyping-based approach to load EV membranes with the receptor-binding domain (RBD) of the viral spike protein, the key domain in SARS-CoV-2 attachment, fusion and cellular entry. The RBD-tagged EVs can specifically recognize ACE2 receptor on the surface of target cells, which is required for the RBD-tagged EVs cellular uptake and targeting. Further, using the hACE2 transgenic mouse model, we show the RBD-tagged EVs accumulate specifically in the target tissues that highly express ACE2. Finally, we demonstrate that the RBD-tagged EVs that encapsulate siRNAs against SARS-CoV-2 pseudovirus can specifically target lung tissues and suppress the pseudovirus infection in vivo. Together, our work presents a safe and effective engineered EV system for in vivo targeted delivery of potential antiviral agents into specific tissues which as a therapeutic potential against SARS-CoV-2 infection.

The Application Potential and Advance of Mesenchymal Stem Cell-Derived Exosomes in Myocardial Infarction

Myocardial infarction (MI) is a devastating disease with high morbidity and mortality caused by the irreversible loss of functional cardiomyocytes and heart failure (HF) due to the restricted blood supply. Mesenchymal stem cells (MSCs) have been emerging as lead candidates to treat MI and subsequent HF mainly through secreting multitudinous factors of which exosomes act as the most effective constituent to boost the repair of heart function through carrying noncoding RNAs and proteins. Given the advantages of higher stability in the circulation, lower toxicity, and controllable transplantation dosage, exosomes have been described as a wonderful and promising cell-free treatment method in cardiovascular disease. Nowadays, MSC-derived exosomes have been proposed as a promising therapeutic approach to improve cardiac function and reverse heart remodeling. However, exosomes' lack of modification cannot result in desired therapeutic effect. Hence, optimized exosomes can be developed via various engineering methods such as pharmacological compound preconditioned MSCs, genetically modified MSCs, or miRNA-loaded exosomes and peptide tagged exosomes to improve the targeting and therapeutic effects of exosomes. The biological characteristics, therapeutic potential, and optimizing strategy of exosomes will be described in our review.

Biodistribution of extracellular vesicles following administration into animals: A systematic review

In recent years, attention has turned to examining the biodistribution of EVs in recipient animals to bridge between knowledge of EV function in vitro and in vivo. We undertook a systematic review of the literature to summarize the biodistribution of EVs following administration into animals. There were time-dependent changes in the biodistribution of small-EVs which were most abundant in the liver. Detection peaked in the liver and kidney in the first hour after administration, while distribution to the lungs and spleen peaked between 2-12 h. Large-EVs were most abundant in the lungs with localization peaking in the first hour following administration and decreased between 2-12 h. In contrast, large-EV localization to the liver increased as the levels in the lungs decreased. There was moderate to low localization of large-EVs to the kidneys while localization to the spleen was typically low. Regardless of the origin or size of the EVs or the recipient species into which the EVs were administered, the biodistribution of the EVs was largely to the liver, lungs, kidneys, and spleen. There was extreme variability in the methodology between studies and we recommend that guidelines should be developed to promote standardization where possible of future EV biodistribution studies.

MiR-154-5p-MCP1 Axis Regulates Allergic Inflammation by Mediating Cellular Interactions

In a previous study, we have demonstrated that p62, a selective receptor of autophagy, can regulate allergic inflammation. In the present study, microRNA array analysis showed that miR-154-5p was increased by antigen (DNP-HSA) in a p62-dependent manner in rat basophilic leukemia cells (RBL2H3). NF-kB directly increased the expression of miR-154-5p. miR-154-5p mediated in vivo allergic reactions, including passive cutaneous anaphylaxis and passive systemic anaphylaxis. Cytokine array analysis showed that antigen stimulation increased the expression of MCP1 in RBL2H3 cells in an miR-154-5p-dependent manner. Reactive oxygen species (ROS)-ERK-NF-kB signaling increased the expression of MCP1 in antigen-stimulated RBL2H3 cells. Recombinant MCP1 protein induced molecular features of allergic reactions both in vitro and in vivo. Anaphylaxis-promoted tumorigenic potential has been known to be accompanied by cellular interactions involving mast cells, and macrophages, and cancer cells. Our experiments employing culture medium, co-cultures, and recombinant MCP1 protein showed that miR-154 and MCP1 mediated these cellular interactions. MiR-154-5p and MCP1 were found to be present in exosomes of RBL2H3 cells. Exosomes from PSA-activated BALB/C mouse induced molecular features of passive cutaneous anaphylaxis in an miR-154-5p-dependent manner. Exosomes from antigen-stimulated RBL2H3 cells enhanced both tumorigenic and metastatic potentials of B16F1 melanoma cells in an miR-154-5p-dependent manner. Exosomes regulated both ROS level and ROS mediated cellular interactions during allergic inflammation. Our results indicate that the miR-154-5p-MCP1 axis might serve as a valuable target for the development of anti-allergy therapeutics.

Proteomics Profiling of Neuron-Derived Small Extracellular Vesicles from Human Plasma: Enabling Single-Subject Analysis

Small extracellular vesicles have been intensively studied as a source of biomarkers in neurodegenerative disorders. The possibility to isolate neuron-derived small extracellular vesicles (NDsEV) from blood represents a potential window into brain pathological processes. To date, the absence of sensitive NDsEV isolation and full proteome characterization methods has meant their protein content has been underexplored, particularly for individual patients. Here, we report a rapid method based on an immunoplate covalently coated with mouse monoclonal anti-L1CAM antibody for the isolation and the proteome characterization of plasma-NDsEV from individual Parkinson’s disease (PD) patients. We isolated round-shaped vesicles with morphological characteristics consistent with exosomes. On average, 349 ± 38 protein groups were identified by liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis, 20 of which are annotated in the Human Protein Atlas as being highly expressed in the brain, and 213 were shared with a reference NDsEV dataset obtained from cultured human neurons. Moreover, this approach enabled the identification of 23 proteins belonging to the Parkinson disease KEGG pathway, as well as proteins previously reported as PD circulating biomarkers.

Overview and Update on Methods for Cargo Loading into Extracellular Vesicles

The enormous library of pharmaceutical compounds presents endless research avenues. However, several factors limit the therapeutic potential of these drugs, such as drug resistance, stability, off-target toxicity, and inadequate delivery to the site of action. Extracellular vesicles (EVs) are lipid bilayer-delimited particles and are naturally released from cells. Growing evidence shows that EVs have great potential to serve as effective drug carriers. Since EVs can not only transfer biological information, but also effectively deliver hydrophobic drugs into cells, the application of EVs as a novel drug delivery system has attracted considerable scientific interest. Recently, EVs loaded with siRNA, miRNA, mRNA, CRISPR/Cas9, proteins, or therapeutic drugs show improved delivery efficiency and drug effect. In this review, we summarize the methods used for the cargo loading into EVs, including siRNA, miRNA, mRNA, CRISPR/Cas9, proteins, and therapeutic drugs. Furthermore, we also include the recent advance in engineered EVs for drug delivery. Finally, both advantages and challenges of EVs as a new drug delivery system are discussed. Here, we encourage researchers to further develop convenient and reliable loading methods for the potential clinical applications of EVs as drug carriers in the future.

Extracellular Vesicle Transportation and Uptake by Recipient Cells: A Critical Process to Regulate Human Diseases

Emerging evidence highlights the relevance of extracellular vesicles (EVs) in modulating human diseases including but not limited to cancer, inflammation, and neurological disorders. EVs can be found in almost all types of human body fluids, suggesting that their trafficking may allow for their targeting to remote recipient cells. While molecular processes underlying EV biogenesis and secretion are increasingly elucidated, mechanisms governing EV transportation, target finding and binding, as well as uptake into recipient cells remain to be characterized. Understanding the specificity of EV transport and uptake is critical to facilitating the development of EVs as valuable diagnostics and therapeutics. In this mini review, we focus on EV uptake mechanisms and specificities, as well as their implications in human diseases.

Recent progress in the use of microRNAs as biomarkers for drug-induced toxicities in contrast to traditional biomarkers: A comparative review

microRNAs (miRNAs) are small non-coding RNAs with 18-25 nucleotides. They play key regulatory roles in versatile biological process including development and apoptosis, and in disease pathogenesis, for example carcinogenesis, by negatively regulating gene expression. miRNAs often exhibit characteristics suitable for biomarkers such as tissue-specific expression patterns, high stability in serum/plasma, and change in abundance in circulation immediately after toxic injury. Since the discovery of circulating miRNAs in extracellular biological fluids in 2008, there have been many reports on the use of miRNAs as biomarkers for various diseases including cancer and organ injury in humans and experimental animals. In this review article, we have summarized the utility and limitation of circulating miRNAs as safety/toxicology biomarkers for specific tissue injuries including liver, skeletal muscle, heart, retina, and pancreas, by comparing them with conventional protein biomarkers. We have also covered the discovery of miRNAs in serum/plasma and their stability, the knowledge of which is essential for understanding the kinetics of miRNA biomarkers. Since numerous studies have reported the use of these circulating miRNAs as safety biomarkers with high sensitivity and specificity, we believe that circulating miRNAs can promote pre-clinical drug development and improve the monitoring of tissue injuries in clinical pharmacotherapy.

Local administration of stem cell-derived extracellular vesicles in a thermoresponsive hydrogel promotes a pro-healing effect in a rat model of colo-cutaneous post-surgical fistula

Extracellular vesicles (EVs), especially from stem/stromal cells (SCs), represent a cell-free alternative in regenerative medicine holding promises to promote tissue healing while providing safety and logistic advantages in comparison to cellular counterparts. Herein, we hypothesize that SC EVs, administered locally in a thermoresponsive gel, is a therapeutic strategy for managing post-surgical colo-cutaneous fistulas. This disease is a neglected and challenging condition associated to low remission rates and high refractoriness. Herein, EVs from a murine SC line were produced by a high-yield scalable method in bioreactors. The post-surgical intestinal fistula model was induced via a surgical cecostomy communicating the cecum and the skin in Wistar rats. Animals were treated just after cecostomy with PBS, thermoresponsive Pluronic F-127 hydrogel alone or containing SC EVs. A PET-monitored biodistribution investigation of SC EVs labelled with ⁸⁹Zr was performed. Fistula external orifice and output assessment, probe-based confocal laser endomicroscopy, MRI and histology were carried out for therapy follow-up. The relevance of percutaneous EV administration embedded in the hydrogel vehicle was indicated by the PET-biodistribution study. Local administration of SC EVs in the hydrogel reduced colo-cutaneous fistula diameter, output, fibrosis and inflammation while increasing the density of neo-vessels when compared to the PBS and gel groups. This multi-modal investigation pointed-out the therapeutic potential of SC EVs administered locally and in a thermoresponsive hydrogel for the management of challenging post-surgical colon fistulas in a minimally-invasive cell-free strategy.

Plant miR171 modulates mTOR pathway in HEK293 cells by targeting GNA12

Plant microRNAs have shown the capacity to regulate mammalian systems. The potential bioactivity of miR171vr, an isoform of the plant miR171, on human embryonic kidney 293 (HEK293) cells was investigated. Bioinformatics simulations revealed that human G protein subunit alpha 12 (GNA12) transcript could represent an excellent target for miR171vr. To confirm this prediction, in vitro experiments were performed using a synthetic microRNA designed on miR171vr sequence. MiR-treated cells showed a significant decrease of GNA12 mRNA and protein levels, confirming the putative cross-kingdom interaction. In addition, miR171vr determined the modulation of GNA12 downstream signaling factors, including mTOR, as expected. Finally, the effect of the plant miRNA on HEK293 cell growth and its stability in presence of several stressors, such as those miming digestive processes and procedures for preparing food, were evaluated. All this preliminary evidence would suggest that miR171vr, introduced by diet or as supplement in gene therapies, could potentially influence human gene expression, especially for treating disorders where GNA12 is over-expressed (i.e. oral cancer, breast and prostate adenocarcinoma) or mTOR kinase is down-regulated (e.g. obesity, type 2 diabetes, neurodegeneration).

Mesenchymal stem cells secretome: The cornerstone of cell-free regenerative medicine

Mesenchymal stem cells (MSCs) are the most frequently used stem cells in clinical trials due to their easy isolation from various adult tissues, their ability of homing to injury sites and their potential to differentiate into multiple cell types. However, the realization that the beneficial effect of MSCs relies mainly on their paracrine action, rather than on their engraftment in the recipient tissue and subsequent differentiation, has opened the way to cell-free therapeutic strategies in regenerative medicine. All the soluble factors and vesicles secreted by MSCs are commonly known as secretome. MSCs secretome has a key role in cell-to-cell communication and has been proven to be an active mediator of immune-modulation and regeneration both in vitro and in vivo. Moreover, the use of secretome has key advantages over cell-based therapies, such as a lower immunogenicity and easy production, handling and storage. Importantly, MSCs can be modulated to alter their secretome composition to better suit specific therapeutic goals, thus, opening a large number of possibilities. Altogether these advantages now place MSCs secretome at the center of an important number of investigations in different clinical contexts, enabling rapid scientific progress in this field.

Antigen presentation, autoantibody production, and therapeutic targets in autoimmune liver disease

The liver is an important immunological organ that controls systemic tolerance. The liver harbors professional and unconventional antigen-presenting cells that are crucial for tolerance induction and maintenance. Orchestrating the immune response in homeostasis depends on a healthy and well-toned immunological liver microenvironment, which is maintained by the crosstalk of liver-resident antigen-presenting cells and intrahepatic and liver-infiltrating leukocytes. In response to pathogens or autoantigens, tolerance is disrupted by unknown mechanisms. Intrahepatic parenchymal and nonparenchymal cells exhibit unique antigen-presenting properties. The presentation of microbial and endogenous lipid-, metabolite- and peptide-derived antigens from the gut via conventional and nonconventional mechanisms can educate intrahepatic immune cells and elicit effector responses or tolerance. Perturbation of this balance results in autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. Although the exact etiologies of these autoimmune liver diseases are unknown, it is thought that the disruption of tolerance towards self-antigens and microbial metabolites and lipids, as well as alterations in bile acid composition, may result in changes in effector cell activation and polarization and may reduce or impair protective anti-inflammatory regulatory T and B cell responses. Additionally, the canonical and noncanonical transmission of antigens and antigen:MHC complexes via trogocytosis or extracellular vesicles between different (non) immune cells in the liver may play a role in the induction of hepatic inflammation and tolerance. Here, we summarize emerging aspects of antigen presentation, autoantibody production, and the application of novel therapeutic approaches in the characterization and treatment of autoimmune liver diseases.

A hypothesis-generating scoping review of miRs identified in both multiple sclerosis and dementia, their protein targets, and miR signaling pathways

Cognitive impairment (CI) is a frequent complication affecting people with multiple sclerosis (MS). The causes of CI in MS are not fully understood. Besides MRI measures, few other biomarkers exist to help us predict the development of CI and understand its biology. MicroRNAs (miRs) are relatively stable, non-coding RNA molecules about 22 nucleotides in length that can serve as biomarkers and possible therapeutic targets in several autoimmune and neurodegenerative diseases, including the dementias. In this review, we identify dysregulated miRs in MS that overlap with dysregulated miRs in cognitive disorders and dementia and explore how these overlapping miRs play a role in CI in MS. MiR-15, miR-21, miR-128, miR-132, miR-138, miR-142, miR-146a, miR-155, miR-181, miR-572, and let-7 are known to contribute to various forms of dementia and show abnormal expression in MS. These overlapping miRs are involved in pathways related to apoptosis, neuroinflammation, glutamate toxicity, astrocyte activation, microglial burst activity, synaptic dysfunction, and remyelination. The mechanisms of action suggest that these miRs may be related to CI in MS. From our review, we also delineated miRs that could be neuroprotective in MS, namely miR-23a, miR-219, miR-214, and miR-22. Further studies can help clarify if these miRs are responsible for CI in MS, leading to potential therapeutic targets.

Extracellular Vesicles as Biomarkers in Cancer Immunotherapy

Simple Summary

Extracellular vesicles (EVs) are small particles found throughout the body. EVs are released by living cells and contain cargo representing the cell of origin. In recent years, EVs have gained attention in cancer research. Since the cargo found inside EVs can be traced back to the cell of origin, EVs shed from cancer cells, in particular, may be used to better describe and characterize a patient’s tumor. EVs have been found and isolated from a variety of bodily fluids, including blood, saliva, and amniotic fluid, and therefore offer a non-invasive way of also diagnosing and monitoring patients before, during, and after cancer immunotherapy. The aim of this review article was to summarize some of the recent work conducted in this field and the challenges we face moving forward in utilizing EVs for cancer diagnostic and therapeutic purposes in cancer immunotherapy in the clinical setting.

Abstract

Extracellular vesicles (EVs), including exosomes and microvesicles, are membrane-bound vesicles secreted by most cell types during both physiologic conditions as well in response to cellular stress. EVs play an important role in intercellular communication and are emerging as key players in tumor immunology. Tumor-derived EVs (TDEs) harbor a diverse array of tumor neoantigens and contain unique molecular signature that is reflective of tumor’s underlying genetic complexity. As such they offer a glimpse into the immune tumor microenvironment (TME) and have the potential to be a novel, minimally invasive biomarker for cancer immunotherapy. Immune checkpoint inhibitors (ICI), such as anti- programmed death-1(PD-1) and its ligand (PD-L1) antibodies, have revolutionized the treatment of a wide variety of solid tumors including head and neck squamous cell carcinoma, urothelial carcinoma, melanoma, non-small cell lung cancer, and others. Typically, an invasive tissue biopsy is required both for histologic diagnosis and next-generation sequencing efforts; the latter have become more widespread in daily clinical practice. There is an unmet need for noninvasive or minimally invasive (e.g., plasma-based) biomarkers both for diagnosis and treatment monitoring. Targeted analysis of EVs in biospecimens, such as plasma and saliva could serve this purpose by potentially obviating the need for tissue sample. In this review, we describe the current challenges of biomarkers in cancer immunotherapy as well as the mechanistic role of TDEs in modulating antitumor immune response.

Extracellular Vesicles: New Endogenous Shuttles for miRNAs in Cancer Diagnosis and Therapy?

Extracellular Vesicles (EVs) represent a heterogeneous population of membranous cell-derived structures, including cargo-oriented exosomes and microvesicles. EVs are functionally associated with intercellular communication and play an essential role in multiple physiopathological conditions. Shedding of EVs is frequently increased in malignancies and their content, including proteins and nucleic acids, altered during carcinogenesis and cancer progression. EVs-mediated intercellular communication between tumor cells and between tumor and stromal cells can modulate, through cargo miRNA, the survival, progression, and drug resistance in cancer conditions. These consolidated suggestions and EVs’ stability in bodily fluids have led to extensive investigations on the potential employment of circulating EVs-derived miRNAs as tumor biomarkers and potential therapeutic vehicles. In this review, we highlight the current knowledge about circulating EVs-miRNAs in human cancer and the application limits of these tools, discussing their clinical utility and challenges in functions such as in biomarkers and instruments for diagnosis, prognosis, and therapy.

Deficiency of miR-208a Exacerbates CCl4-Induced Acute Liver Injury in Mice by Activating Cell Death Pathways

Acute liver injury (ALI) is associated with multiple cellular events such as necrosis, apoptosis, oxidative stress and inflammation, which can lead to liver failure. In this study, we demonstrate a new role of microRNA (miR)‐208a in ALI. ALI was induced in wild‐type (WT) and miR‐208a knockout (KO) mice by CCl₄ administration. Increased alanine aminotransferase and decreased hepatic miR‐208a levels were found in WT mice after acute CCl₄ treatment. Histopathological evaluations revealed increased necrosis and decreased inflammation in miR‐208a KO compared with WT mice after CCl₄ treatment. CCl₄ treatment induced a higher alanine aminotransferase elevation and increased numbers of circulating extracellular vesicles (exosomes and microvesicles) in miR‐208a KO compared with WT mice. We found increased CCl₄‐induced nuclear factor kappa B activation and tumor necrosis factor‐α induction and decreased monocyte chemoattractant protein 1 levels in miR‐208a KO compared with WT mice. Terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick‐end labeling assay indicated aggravated hepatic apoptosis and necrosis in CCl₄‐treated miR‐208a KO compared with WT mice. CCl₄ treatment induced a greater increase in cleaved caspase‐8, p18, and caspase‐3 in miR‐208a KO compared with WT mice. p53 is involved in various cell death pathways, including necrosis and apoptosis. Our in silico analysis revealed p53 as a predicted miR‐208a target, and we found enhanced p53 and cyclophilin D protein expressions in miR‐208a KO mice after CCl₄ treatment. Increased liver injury in miR‐208a KO mice was further associated with increased Bax (B cell lymphoma 2–associated X protein) and p21 expression. Our in vitro results indicated a role of miR‐208a in cell death. We found that CCl₄‐induced cytotoxicity was partially rescued by miR‐208a overexpression in RAW macrophages. Altogether, our results revealed a role of miR‐208a in ALI in mice and suggest a role for miR‐208a in regulating cell death.

Biomimetic nanovesicle design for cardiac tissue repair

Cardiovascular disease is a major cause of mortality and morbidity worldwide. Exosome therapies are promising for cardiac repair. Exosomes transfer cargo between cells, have high uptake by native cells and are ideal natural carriers for proteins and nucleic acids. Despite their proreparative potential, exosome production is dependent on parent cell state with typically low yields and cargo variability. Therefore, there is potential value in engineering exosomes to maximize their benefits by delivering customized, potent cargo for cardiovascular disease. Here, we outline several methods of exosome engineering focusing on three important aspects: optimizing cargo, homing to target tissue and minimizing clearance. Finally, we put these methods in context of the cardiac field and discuss the future potential of vesicle design.

RNA delivery by extracellular vesicles in mammalian cells and its applications

The term 'extracellular vesicles' refers to a heterogeneous population of vesicular bodies of cellular origin that derive either from the endosomal compartment (exosomes) or as a result of shedding from the plasma membrane (microvesicles, oncosomes and apoptotic bodies). Extracellular vesicles carry a variety of cargo, including RNAs, proteins, lipids and DNA, which can be taken up by other cells, both in the direct vicinity of the source cell and at distant sites in the body via biofluids, and elicit a variety of phenotypic responses. Owing to their unique biology and roles in cell-cell communication, extracellular vesicles have attracted strong interest, which is further enhanced by their potential clinical utility. Because extracellular vesicles derive their cargo from the contents of the cells that produce them, they are attractive sources of biomarkers for a variety of diseases. Furthermore, studies demonstrating phenotypic effects of specific extracellular vesicle-associated cargo on target cells have stoked interest in extracellular vesicles as therapeutic vehicles. There is particularly strong evidence that the RNA cargo of extracellular vesicles can alter recipient cell gene expression and function. During the past decade, extracellular vesicles and their RNA cargo have become better defined, but many aspects of extracellular vesicle biology remain to be elucidated. These include selective cargo loading resulting in substantial differences between the composition of extracellular vesicles and source cells; heterogeneity in extracellular vesicle size and composition; and undefined mechanisms for the uptake of extracellular vesicles into recipient cells and the fates of their cargo. Further progress in unravelling the basic mechanisms of extracellular vesicle biogenesis, transport, and cargo delivery and function is needed for successful clinical implementation. This Review focuses on the current state of knowledge pertaining to packaging, transport and function of RNAs in extracellular vesicles and outlines the progress made thus far towards their clinical applications.

MiR-218: a molecular switch and potential biomarker of susceptibility to stress

Low miR-218 expression in the medial prefrontal cortex (mPFC) is a consistent trait of depression. Here we assessed whether miR-218 in the mPFC confers resilience or susceptibility to depression-like behaviors in adult mice, using the chronic social defeat stress (CSDS) model of depression. We also investigated whether stress-induced variations of miR-218 expression in the mPFC can be detected in blood. We find that downregulation of miR-218 in the mPFC increases susceptibility to a single session of social defeat, whereas overexpression of miR-218 selectively in mPFC pyramidal neurons promotes resilience to CSDS and prevents stress-induced morphological alterations to those neurons. After CSDS, susceptible mice have low levels of miR-218 in blood, as compared with control or resilient groups. We show further that upregulation and downregulation of miR-218 levels specifically in the mPFC correlate with miR-218 expression in blood. Our results suggest that miR-218 in the adult mPFC might function as a molecular switch that determines susceptibility vs. resilience to chronic stress, and that stress-induced variations in mPFC levels of miR-218 could be detected in blood. We propose that blood expression of miR-218 might serve as potential readout of vulnerability to stress and as a proxy of mPFC function.

Cholangiocarcinoma: novel therapeutic targets

Introduction: Cholangiocarcinoma (CCA) is a liver cancer derived from the biliary tree with a less than 30% five-year survival rate. Early diagnosis of CCA is challenging and treatment options are limited. Some CCA patients have genetic mutations and several therapeutic drugs or antibodies have been introduced to target abnormally expressed proteins. However, CCA is heterogeneous and patients often present with drug resistance which is attributed to multiple mutations or other factors. Novel approaches and methodologies for CCA treatments are in demand.Area covered: This review summarizes current approaches for CCA treatments leading to the development of novel therapeutic drugs or tools for human CCA patients. A literature search was conducted in PubMed utilizing the combination of the searched term 'cholangiocarcinoma' with other keywords such as 'miRNA', 'FGFR', 'immunotherapy' or 'microenvironment'. Papers published within 2015-2019 were obtained for reading.Expert opinion: Preclinical studies have demonstrated promising therapeutic approaches that target various cells or pathways. Recent studies have revealed that hepatic cells coordinate to promote CCA tumor progression in the tumor microenvironment, which may be a new therapeutic target. Although further studies are required, novel therapeutic tools such as extracellular vesicles could be utilized to manage CCA and its microenvironment.

Exosomes in Therapy: Engineering, Pharmacokinetics and Future Applications

BACKGROUND

Eukaryotic cells release vesicles of different sizes under both physiological and pathological conditions. On the basis of the respective biogenesis, extracellular vesicles are classified as apoptotic bodies, microvesicles, and exosomes. Among these, exosomes are considered tools for innovative therapeutic interventions, especially when engineered with effector molecules. The delivery functions of exosomes are favored by a number of typical features. These include their small size (i.e., 50-200 nm), the membrane composition tightly similar to that of producer cells, lack of toxicity, stability in serum as well as other biological fluids, and accession to virtually any organ and tissue including central nervous system. However, a number of unresolved questions still affects the possible use of exosomes in therapy. Among these are the exact identification of both in vitro and ex vivo produced vesicles, their large-scale production and purification, the uploading efficiency of therapeutic macromolecules, and the characterization of their pharmacokinetics.

OBJECTIVE

Here, we discuss two key aspects to be analyzed before considering exosomes as a tool of delivery for the desired therapeutic molecule, i.e., techniques of engineering, and their in vivo biodistribution/ pharmacokinetics. In addition, an innovative approach aimed at overcoming at least part of the obstacles towards a safe and efficient use of exosomes in therapy will be discussed.

CONCLUSION

Several biologic features render exosomes an attractive tool for the delivery of therapeutic molecules. They will surely be a part of innovative therapeutic interventions as soon as few still unmet technical hindrances will be overcome.

Concise Review: Functional Roles and Therapeutic Potentials of Long Non-coding RNAs in Cholangiopathies

Long non-coding RNAs (lncRNAs) are RNAs with lengths exceeding 200 nucleotides that are not translated into proteins. It is well-known that small non-coding RNAs, such as microRNAs (miRNAs), regulate gene expression and play an important role in cholangiopathies. Recent studies have demonstrated that lncRNAs may also play a key role in the pathophysiology of cholangiopathies. Patients with cholangiopathies often develop cholangiocarcinoma (CCA), which is cholangiocyte-derived cancer, in the later stage. Cholangiocytes are a primary target of therapies for cholangiopathies and CCA development. Previous studies have demonstrated that expression levels of lncRNAs are altered in the liver of cholangiopathies or CCA tissues. Some lncRNAs regulate gene expression by inhibiting functions of miRNAs leading to diseased liver conditions or CCA progression, suggesting that lncRNAs could be a novel therapeutic target for those disorders. This review summarizes current understandings of functional roles of lncRNAs in cholangiopathies and seek their potentials for novel therapies.