Methods for the Determination of the Purity of Exosomes

The potential mechanisms and treatment effects of stem cell-derived exosomes in cardiac reengineering

Exosomes are extracellular vesicles of diverse compositions that are secreted by numerous cell types. Exosomes contain significant bioactive components, including lipids, proteins, mRNA, and miRNA. Exosomes play an important role in regulating cellular signaling and trafficking under both normal physiological and pathological circumstances. A multitude of factors, including thermal stress, ribosomal stress, endoplasmic reticulum stress, and oxidative stress influence the concentrations of exosomal mRNA, miRNA, proteins, and lipids. It has been stated that exosomes derived from stem cells (SCs) modulate a range of stresses by preventing or fostering cell balance. Exosomes derived from SCs facilitate recovery by facilitating cross-cellular communication via the transmission of information in the form of proteins, lipids, and other components. For this reason, exosomes are used as biomarkers to diagnose a wide variety of diseases. The focus of this review is the bioengineering of artificial exosomal cargoes. This process encompasses the control and transportation of particular exosomal cargoes, including but not limited to small molecules, recombinant proteins, immune modulators, and therapeutic medications. Therapeutic approaches of this nature have the potential to deliver therapeutic medications precisely to the intended site for the cure of a variety of disorders. Notably, our attention has been directed towards the therapeutic implementations of exosomes derived from SCs in the cure of cardiovascular ailments, including but not limited to ischemic heart disease, myocardial infarction, sepsis, heart failure, cardiomyopathy, and cardiac fibrosis. In general, researchers employ two methodologies when it comes to exosomal bioengineering. This review aims to explain the function of exosomes derived from SCs in the regulation of stress and present a novel therapeutic approach for cardiovascular disorders.

The use of platelets as a clinical tool in oncology: opportunities and challenges

Platelets are small circulating anucleated cells mainly involved in thrombosis and hemostasis processes. Moreover, platelets play an active role in tumorigenesis and cancer progression, stimulating angiogenesis and vascular remodelling, and protecting circulating cancer cells from shear forces and immune surveillance. Several reports indicate that platelet number in the blood circulation of cancer patients is associated with prognosis and response to treatment. However, the mechanisms of platelets "education" by cancer cells and the crosstalk between platelets and tumor are still unclear, and the role of "tumor educated platelets" (TEPs) is achieving growing interest in cancer research. TEPs are a biological source of cancer-derived biomarkers, especially RNAs that are protected by platelets membrane from circulating RNases, and could serve as a non-invasive tool for tumor detection, molecular profiling and evolution during therapy in clinical practice. Moreover, short platelet lifespan offers the possibility to get a snapshot assessment of cancer molecular profile, providing a real-time tool. We review and discuss the potential and the clinical utility, in terms of cancer diagnosis and monitoring, of platelet count together with other morphological parameters and of the more recent and innovative TEP profiling.

Clinical applications of stem cell-derived exosomes

Although stem cell-based therapy has demonstrated considerable potential to manage certain diseases more successfully than conventional surgery, it nevertheless comes with inescapable drawbacks that might limit its clinical translation. Compared to stem cells, stem cell-derived exosomes possess numerous advantages, such as non-immunogenicity, non-infusion toxicity, easy access, effortless preservation, and freedom from tumorigenic potential and ethical issues. Exosomes can inherit similar therapeutic effects from their parental cells such as embryonic stem cells and adult stem cells through vertical delivery of their pluripotency or multipotency. After a thorough search and meticulous dissection of relevant literature from the last five years, we present this comprehensive, up-to-date, specialty-specific and disease-oriented review to highlight the surgical application and potential of stem cell-derived exosomes. Exosomes derived from stem cells (e.g., embryonic, induced pluripotent, hematopoietic, mesenchymal, neural, and endothelial stem cells) are capable of treating numerous diseases encountered in orthopedic surgery, neurosurgery, plastic surgery, general surgery, cardiothoracic surgery, urology, head and neck surgery, ophthalmology, and obstetrics and gynecology. The diverse therapeutic effects of stem cells-derived exosomes are a hierarchical translation through tissue-specific responses, and cell-specific molecular signaling pathways. In this review, we highlight stem cell-derived exosomes as a viable and potent alternative to stem cell-based therapy in managing various surgical conditions. We recommend that future research combines wisdoms from surgeons, nanomedicine practitioners, and stem cell researchers in this relevant and intriguing research area.

Exosomes as Targeted Delivery Drug System: Advances in Exosome Loading, Surface Functionalization and Potential for Clinical Application

Exosomes are subtypes of vesicles secreted by almost all cells and can play an important role in intercellular communication. They contain various proteins, lipids, nucleic acids and other natural substances from their metrocytes. Exosomes are expected to be a new generation of drug delivery systems due to their low immunogenicity, high potential to transfer bioactive substances and biocompatibility. However, exosomes themselves are not highly targeted, it is necessary to develop new surface modification techniques and targeted drug delivery strategies, which are the focus of drug delivery research. In this review, we introduced the biogenesis of exosomes and their role in intercellular communication. We listed various advanced exosome drug-loading techniques. Emphatically, we summarized different exosome surface modification techniques and targeted drug delivery strategies. In addition, we discussed the application of exosomes in vaccines and briefly introduced milk exosomes. Finally, we clarified the clinical application prospects and shortcomings of exosomes.

Challenges and future scope of exosomes in the treatment of cardiovascular diseases

Exosomes are nanosized vesicles that carry biologically diverse molecules for intercellular communication. Researchers have been trying to engineer exosomes for therapeutic purposes by using different approaches to deliver biologically active molecules to the various target cells efficiently. Recent technological advances may allow the biodistribution and pharmacokinetics of exosomes to be modified to meet scientific needs with respect to specific diseases. However, it is essential to determine an exosome's optimal dosage and potential side effects before its clinical use. Significant breakthroughs have been made in recent decades concerning exosome labelling and imaging techniques. These tools provide in situ monitoring of exosome biodistribution and pharmacokinetics and pinpoint targetability. However, because exosomes are nanometres in size and vary significantly in contents, a deeper understanding is required to ensure accurate monitoring before they can be applied in clinical settings. Different research groups have established different approaches to elucidate the roles of exosomes and visualize their spatial properties. This review covers current and emerging strategies for in vivo and in vitro exosome imaging and tracking for potential studies.

Integrated therapy platform of exosomal system: hybrid inorganic/organic nanoparticles with exosomes for cancer treatment

Recent studies have found that exosomes or extracellular vehicles (EVs) are associated with cancer metastasis, disease progression, diagnosis, and treatment, leading to a rapidly emerging area of exocrine vesicle research. Relying on the superior targeting function and bio-compatibility of exosomes, researchers have been able to deliver drugs to cancer stem cells deep within tumors in mouse models. Despite significant efforts made in this relatively new field of exosome research, progress has been held back by challenges such as inefficient separation methods, difficulties in characterization/tracking, and a lack of specific biomarkers. Therefore, current researches are devoted to combining nanomaterials with exosomes to improve these shortcomings. Adding inorganic/organic nanoparticles such as artificial liposomes and iron oxide can bring more drug options and various fluorescent or magnetic diagnostic possibilities to the exosome system. Moreover, the applications of exosomes need to be further evaluated under actual physiological conditions. This review article highlights the potential of exosome-biomimetic nanoparticles for their use as drug carriers to improve the efficacy of anticancer therapy.

Matrix Vesicles as a Therapeutic Target for Vascular Calcification

Vascular calcification (VC) is linked to an increased risk of heart disease, stroke, and atherosclerotic plaque rupture. It is a cell-active process regulated by vascular cells rather than pure passive calcium (Ca) deposition. In recent years, extracellular vesicles (EVs) have attracted extensive attention because of their essential role in the process of VC. Matrix vesicles (MVs), one type of EVs, are especially critical in extracellular matrix mineralization and the early stages of the development of VC. Vascular smooth muscle cells (VSMCs) have the potential to undergo phenotypic transformation and to serve as a nucleation site for hydroxyapatite crystals upon extracellular stimulation. However, it is not clear what underlying mechanism that MVs drive the VSMCs phenotype switching and to result in calcification. This article aims to review the detailed role of MVs in the progression of VC and compare the difference with other major drivers of calcification, including aging, uremia, mechanical stress, oxidative stress, and inflammation. We will also bring attention to the novel findings in the isolation and characterization of MVs, and the therapeutic application of MVs in VC.

Circ-SKA3 Enhances Doxorubicin Toxicity in AC16 Cells Through miR-1303/TLR4 Axis

Doxorubicin (DOX) is a widely used anticancer drug, but its cardiotoxicity largely limits its clinical utilization. Circular RNA spindle and kinetochore-associated protein 3 (circ-SKA3) were found to be differentially expressed in heart failure patients. In this study, we investigated the role and mechanism of circ-SKA3 in DOX-induced cardiotoxicity.The quantitative real-time polymerase chain reaction and western blot assays were applied to measure the expression of circ-SKA3, microRNA (miR) -1303, and toll-like receptor 4 (TLR4). The viability and apoptosis of AC16 cells were analyzed using cell counting kit-8, flow cytometry, and western blot assays. The interaction between miR-1303 and circ-SKA3 or TLR4 was verified using dual-luciferase reporter and RNA immunoprecipitation assays. Exosomes were collected from culture media by the use of commercial kits and then qualified by transmission electron microscopy.The expression of circ-SKA3 and TLR4 was increased, whereas miR-1303 expression was decreased in DOX-treated AC16 cells. DOX treatment promoted cell apoptosis and inhibited cell viability in AC16 cells in vitro, which was partially reversed by circ-SKA3 knockdown, TLR4 silencing, or miR-1303 overexpression. Mechanistically, circ-SKA3 served as a sponge for miR-1303 to upregulate TLR4, which was confirmed to be a target of miR-1303. Additionally, circ-SKA3 contributed to DOX-induced cardiotoxicity through the miR-1303/TLR4 axis. Further studies suggested that circ-SKA3 was overexpressed in exosomes extracted from DOX-mediated AC16 cells, which could be internalized by surrounding untreated AC16 cells.Circ-SKA3 enhanced DOX-induced toxicity in AC16 cells through the miR-1303/TLR4 axis. Extracellular circ-SKA3 was packaged into exosomes, and exosomal circ-SKA3 could function as a mediator in intercellular communication between AC16 cells.

A review on the role of CAFs and CAF-derived exosomes in progression and metastasis of digestive system cancers

Cancers evolve as a result of the accelerated proliferation of cancer cells in a complicated, enriched, and active microenvironment. Tumor microenvironment (TME) components are the master regulators of any step of cancer development. The tumor microenvironment is composed of many cellular and noncellular components that contribute to the evolution of cancer cells. Cancer-associated fibroblasts (CAFs) are activated fibroblasts in the TME that implicate in tumor progression and metastasis dissemination through secretion of oncogenic factors which are carried to the secondary metastatic sites through exosomes. In this review, we aimed to assess the role of CAF-derived exosomes in TME construction and pre-metastatic niche formation in different cancers of the digestive system in order to better understand some important mechanisms of metastasis and provide possible targets for clinical intervention. This review article is divided into two thematic parts explaining the general mechanisms of pre-metastatic niche formation and metastasis and the role of CAF-derived exosomes in different digestive system cancers including colorectal, gastric, esophageal, pancreatic, and liver cancers.

CRISPR/Cas9: Principle, Applications, and Delivery through Extracellular Vesicles

The establishment of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) technology for eukaryotic gene editing opened up new avenues not only for the analysis of gene function but also for therapeutic interventions. While the original methodology allowed for targeted gene disruption, recent technological advancements yielded a rich assortment of tools to modify genes and gene expression in various ways. Currently, clinical applications of this technology fell short of expectations mainly due to problems with the efficient and safe delivery of CRISPR/Cas9 components to living organisms. The targeted in vivo delivery of therapeutic nucleic acids and proteins remain technically challenging and further limitations emerge, for instance, by unwanted off-target effects, immune reactions, toxicity, or rapid degradation of the transfer vehicles. One approach that might overcome many of these limitations employs extracellular vesicles as intercellular delivery devices. In this review, we first introduce the CRISPR/Cas9 system and its latest advancements, outline major applications, and summarize the current state of the art technology using exosomes or microvesicles for transporting CRISPR/Cas9 constituents into eukaryotic cells.

Sequential Release of Small Extracellular Vesicles from Bilayered Thiolated Alginate/Polyethylene Glycol Diacrylate Hydrogels for Scarless Wound Healing

Excessive scar formation has adverse physiological and psychological effects on patients; therefore, a therapeutic strategy for rapid wound healing and reduced scar formation is urgently needed. Herein, bilayered thiolated alginate/PEG diacrylate (BSSPD) hydrogels were fabricated for sequential release of small extracellular vesicles (sEVs), which acted in different wound healing phases, to achieve rapid and scarless wound healing. The sEVs secreted by bone marrow derived mesenchymal stem cells (B-sEVs) were released from the lower layer of the hydrogels to promote angiogenesis and collagen deposition by accelerating fibroblast and endothelial cell proliferation and migration during the early inflammation and proliferation phases, while sEVs secreted by miR-29b-3p-enriched bone marrow derived mesenchymal stem cells were released from the upper layer of the hydrogels and suppressed excessive capillary proliferation and collagen deposition during the late proliferation and maturation phases. In a full-thickness skin defect model of rats and rabbit ears, the wound repair rate, angiogenesis, and collagen deposition were evaluated at different time points after treatment with BSSPD loaded with B-sEVs. Interestingly, during the end of the maturation phase in the in vivo model, tissues in the groups treated with BSSPD loaded with sEVs for sequential release (SR-sEVs@BSSPD) exhibited a more uniform vascular structure distribution, more regular collagen arrangement, and lower volume of hyperplastic scar tissue than tissues in the other groups. Hence, SR-sEVs@BSSPD based on skin repair phases was successfully designed and has considerable potential as a cell-free therapy for scarless wound healing.

Co-Isolation of Cytokines and Exosomes: Implications for Immunomodulation Studies

Exosomes play a vital role in intercellular communication and their immunomodulatory potential have become an important focus in cancer research. Various methods have been developed for the isolation although each method differs in the number and purity of exosomes they yield. In melanoma, tumor-derived exosomes drive immunosuppression within the tumor microenvironment. The co-elution of exosomes and soluble factors such as cytokines during isolation, however, make it difficult to ascertain the contribution of exosome cargo, as soluble cytokines are equally capable of immune suppression. In this review we will expound upon the biological relevance that exosome-associated cytokines possess. Furthermore, we discuss the technical challenges that arise during exosome isolation and what this means for further studies into the TME and in vivo work.

EV Separation: Release of Intact Extracellular Vesicles Immunocaptured on Magnetic Particles

Extracellular vesicles (EVs) have attracted considerable interest due to their role in cell-cell communication, disease diagnosis, and drug delivery. Despite their potential in the medical field, there is no consensus on the best method for separating micro- and nanovesicles from cell culture supernatant and complex biological fluids. Obtaining a good recovery yield and preserving physical characteristics is critical for the diagnostic and therapeutic use of EVs. The separation of a single class of EVs, such as exosomes, is complex because blood and cell culture media contain many nanoparticles in the same size range. Methods that exploit immunoaffinity capture provide high-purity samples and overcome the issues of currently used separation methods. However, the release of captured nanovesicles usually requires harsh conditions that hinder their use in certain types of downstream analysis. A novel capture and release approach for small extracellular vesicles (sEVs) is presented based on DNA-directed immobilization of antiCD63 antibody. The flexible DNA linker increases the capture efficiency and allows for releasing EVs by exploiting the endonuclease activity of DNAse I. This separation protocol works under mild conditions, enabling the release of vesicles suitable for analysis by imaging techniques. In this study, sEVs recovered from plasma were characterized by established techniques for EV analysis, including nanoparticle tracking and transmission electron microscopy.

A Spectrum of Topics for 2019: Advances in Neuroinflammation, Oxidative Stress, Obesity, Diabetes Mellitus, Cardiovascular Disease, Autism, Exosomes, and Central Nervous System Diseases

Advances in various fields were discussed in the reviews and original research articles published in 2019 in Current Pharmaceutical Design. Here, I review some of the major highlights for selected areas. A better understanding of disease mechanisms was a prominent recurrent theme and new therapeutic targets based on those mechanisms are highlighted here. Inflammation and oxidative stress are major features of many diseases, therefore, interventions to address these processes are reviewed. Although repurposing of old drugs occurred in several fields, drug targeting and drug delivery, especially of nanoparticles, also continues to be a major area of interest.

The role of extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a rare tumor that arises from cholangiocytes, the epithelial cells of the bile duct. The tumor is characterized by insidious onset, high degree of malignancy, poor prognosis and high recurrence rate. Due to the lack of specific biomarkers, it is difficult to diagnose CCA early and evaluate prognosis. Extracellular vesicles (EVs), which include apoptotic bodies, microvesicles and exosomes, have emerged as having important roles in cell-to-cell communication in both normal physiology and pathological conditions. Some research has found that EVs play a crucial role in the occurrence and development of CCA. EVs can carry specific molecular substances such as nucleic acids and proteins, which have potential for the diagnosis and therapy of CCA. This article reviews the current knowledge on the role of EVs in CCA. We highlight EVs and their functions in the physiology and pathophysiology of CCA, and discuss their therapeutic potential and their role as biomarkers.

Exosomes as Messengers Between Mother and Fetus in Pregnancy

The ability of exosomes to transport different molecular cargoes and their ability to influence various physiological factors is already well known. An exciting area of research explores the functions of exosomes in healthy and pathological pregnancies. Placenta-derived exosomes were identified in the maternal circulation during pregnancy and their contribution in the crosstalk between mother and fetus are now starting to become defined. In this review, we will try to summarize actual knowledge about this topic and to answer the question of how important exosomes are for a healthy pregnancy.