Biocompatibility of highly purified bovine milk-derived extracellular vesicles

Multifaceted effects of milk-exosomes (Mi-Exo) as a modulator of scar-free wound healing

Scar-free treatment is complex involving many cells in the human body but a very elaborate reaction. This process demands regulation of various growth factors on behalf of TGFβ3 around the damaged tissue, and it is also important to protect cells from inflammatory reactions and oxidative stress to avoid abnormalities. Here, we focused on bovine derived milk exosomes (Mi-Exo) and their scar-free healing potential. The physiological properties (size and shape), biological markers (TSG101 and Bta-miR2478) and stability on storage of Mi-Exo were analyzed. Mi-Exo exhibited significant NP (number of Mi-Exo particles)-dependent scavenging activity in ABTS assay. In addition, Mi-Exo suppressed the expression of pro-inflammatory mediators, IL-6 and TNFα, and pro-inflammatory chemokines, COX-2 and iNOS. This study showed that cell migration was significantly inhibited in a Mi-Exo NP-dependent manner. We also evaluated the expression of TGFβ1 and TGFβ3 on the basis of mRNA and protein levels. Furthermore, the role of functional behavior of Mi-Exo in TGFβ1 maturation was explored. This is the first study to demonstrate that Mi-Exo may target the TGFβ signaling pathway, which plays important roles in scar-free wound healing.

Extracellular vesicles-derived miR-150-5p secreted by adipose-derived mesenchymal stem cells inhibits CXCL1 expression to attenuate hepatic fibrosis

Hepatic fibrosis (HF) is involved in aggravated wound‐healing response as chronic liver injury. Extracellular vesicles (EVs) carrying microRNA (miR) have been reported as therapeutic targets for liver diseases. In this study, we set out to explore whether adipose‐derived mesenchymal stem cells (ADMSCs)‐derived EVs containing miR‐150‐5p affect the progression of HF. Carbon tetrachloride (CCl₄) was firstly used to induce HF mouse models in C57BL/6J mice, and activation of hepatic stellate cells (HSCs) was achieved using transforming growth factor β (TGF‐β). EVs were then isolated from ADMSCs and co‐cultured with HSCs. The relationship between miR‐150‐5p and CXCL1 was identified using dual luciferase gene reporter assay. Following loss‐ and gain‐function experimentation, HSC proliferation was examined by MTT assay, and levels of fibrosis‐, HSC activation‐ and apoptosis‐related genes were determined in vitro. Additionally, pathological scores, collagen volume fraction (CVF) as well as levels of inflammation‐ and hepatic injury‐associated genes were determined in in vivo. Down‐regulated miR‐150‐5p and elevated CXCL1 expression levels were detected in HF tissues. ADMSCs‐derived EVs transferred miR‐150‐5p to HSCs. CXCL1 was further verified as the downstream target gene of miR‐150‐5p. Moreover, ADMSCs‐EVs containing miR‐150‐5p markedly inhibited HSC proliferation and activation in vitro. Meanwhile, in vivo experiments also concurred with the aforementioned results as demonstrated by inhibited CVF, reduced inflammatory factor levels and hepatic injury‐associated indicators. Both experiments results were could be reversed by CXCL1 over‐expression. Collectively, our findings indicate that ADMSCs‐derived EVs containing miR‐150‐5p attenuate HF by inhibiting the CXCL1 expression.

Exosomes in disease and regeneration: biological functions, diagnostics, and beneficial effects

Exosomes are a subtype of extracellular vesicles. They range from 30 to 150 nm in diameter and originate from intraluminal vesicles. Exosomes were first identified as the mechanism for releasing unnecessary molecules from reticulocytes as they matured to red blood cells. Since then, exosomes have been shown to be secreted by a broad spectrum of cells and play an important role in the cardiovascular system. Different stimuli are associated with increased exosome release and result in different exosome content. The release of harmful DNA and other molecules via exosomes has been proposed as a mechanism to maintain cellular homeostasis. Because exosomes contain parent cell-specific proteins on the membrane and in the cargo that is delivered to recipient cells, exosomes are potential diagnostic biomarkers of various types of diseases, including cardiovascular disease. As exosomes are readily taken up by other cells, stem cell-derived exosomes have been recognized as a potential cell-free regenerative therapy to repair not only the injured heart but other tissues as well. The objective of this review is to provide an overview of the biological functions of exosomes in heart disease and tissue regeneration. Therefore, state-of-the-art methods for exosome isolation and characterization, as well as approaches to assess exosome functional properties, are reviewed. Investigation of exosomes provides a new approach to the study of disease and biological processes. Exosomes provide a potential "liquid biopsy," as they are present in most, if not all, biological fluids that are released by a wide range of cell types.

Evaluation of bovine milk extracellular vesicles for the delivery of locked nucleic acid antisense oligonucleotides

The natural capacity of extracellular vesicles (EVs) to transport their payload to recipient cells has raised big interest to repurpose EVs as delivery vehicles for xenobiotics. In the present study, bovine milk-derived EVs (BMEVs) were investigated for their potential to shuttle locked nucleic acid-modified antisense oligonucleotides (LNA ASOs) into the systemic circulation after oral administration. To this end, a broad array of analytical methods including proteomics and lipidomics were used to thoroughly characterize BMEVs. We found that additional purification by density gradients efficiently reduced levels of non-EV associated proteins. The potential of BMEVs to functionally transfer LNA ASOs was tested using advanced in vitro systems (i.e. hPSC-derived neurons and primary human cells). A slight increase in cellular LNA ASO internalization and target gene reduction was observed when LNA ASOs were delivered using BMEVs. When dosed orally in mice, only a small fraction (about 1% of total administered dose) of LNA ASOs was recovered in the peripheral tissues liver and kidney, however, no significant reduction in target gene expression (i.e. functional knockdown) was observed.

Biological Characteristics and Roles of Noncoding RNAs in Milk-Derived Extracellular Vesicles

Extracellular vesicles (EVs) have diverse roles in the transport of proteins, lipids, and nucleic acids between cells, and they serve as mediators of intercellular communication. Noncoding RNAs (ncRNAs) that are present in EVs, including microRNAs, long noncoding RNAs, and circular RNAs, have been found to participate in complex networks of interactions and regulate a wide variety of genes in animals. Milk is an important source of nutrition for humans and other mammals. Evidence suggests that milk-derived EVs contain abundant ncRNAs, which are stable and can be transported to the offspring and other consumers. Current data suggest a strong link between milk EV ncRNAs and many biological processes, and these ncRNAs have been drawing increasing attention and might play an epigenetic regulatory role in recipients, though further research is still necessary to understand their precise roles. The present review introduces basic information about milk EV ncRNAs, summarizes their expression profiles, biological characteristics, and functions based on current knowledge, and discusses their biological roles, indeterminate issues, and perspectives. Our goal is to provide a deeper understanding of the physiological effects of milk EV ncRNAs on offspring and to provide a reference for future research in this field.

Extracellular Vesicles as an Efficient and Versatile System for Drug Delivery

Despite the recent advances in drug development, the majority of novel therapeutics have not been successfully translated into clinical applications. One of the major factors hindering their clinical translation is the lack of a safe, non-immunogenic delivery system with high target specificity upon systemic administration. In this respect, extracellular vesicles (EVs), as natural carriers of bioactive cargo, have emerged as a promising solution and can be further modified to improve their therapeutic efficacy. In this review, we provide an overview of the biogenesis pathways, biochemical features, and isolation methods of EVs with an emphasis on their many intrinsic properties that make them desirable as drug carriers. We then describe in detail the current advances in EV therapeutics, focusing on how EVs can be engineered to achieve improved target specificity, better circulation kinetics, and efficient encapsulation of therapeutic payloads. We also identify the challenges and obstacles ahead for clinical translation and provide an outlook on the future perspective of EV-based therapeutics.

Roles of Regulatory RNAs in Nutritional Control

Small RNAs (sRNAs), including microRNAs (miRNAs), are noncoding RNA (ncRNA) molecules involved in gene regulation. sRNAs play important roles in development; however, their significance in nutritional control and as metabolic modulators is still emerging. The mechanisms by which diet impacts metabolic genes through miRNAs remain an important area of inquiry. Recent work has established how miRNAs are transported in body fluids often within exosomes, which are small cell-derived vesicles that function in intercellular communication. The abundance of other recently identified ncRNAs and new insights regarding ncRNAs as dietary bioactive compounds could remodel our understanding about how foods impact gene expression. Although controversial, some groups have shown that dietary RNAs from plants and animals (i.e., milk) are functional in consumers. In the future, regulating sRNAs either directly through dietary delivery or indirectly by altered expression of endogenous sRNA may be part of nutritional interventions for regulating metabolism.

Extracellular Vesicles in Bone Metastasis: Key Players in the Tumor Microenvironment and Promising Therapeutic Targets

Extracellular vesicles (EVs) are lipid membranous vesicles that are released from every type of cell. It has become clear that EVs are involved in a variety of biological phenomena, including cancer progression, and play critical roles in intracellular communication through the horizontal transfer of cellular cargoes such as proteins, DNA fragments, RNAs including mRNA and non-coding RNAs (microRNA, piRNA, and long non-coding RNA) and lipids. The most common cause of death associated with cancer is metastasis. Recent investigations have revealed that EVs are deeply associated with metastasis. Bone is a preferred site of metastasis, and bone metastasis is generally incurable and dramatically affects patient quality of life. Bone metastasis can cause devastating complications, including hypercalcemia, pathological fractures, spinal compression, and bone pain, which result in a poor prognosis. Although the mechanisms underlying bone metastasis have yet to be fully elucidated, increasing evidence suggests that EVs in the bone microenvironment significantly contribute to cancer progression and cancer bone tropism. Emerging evidence on EV functions in bone metastasis will facilitate the discovery of novel treatments. In this review, we will discuss the remarkable effects of EVs, especially on the tumor microenvironment in bone.

Milk Exosomes: Perspective Agents for Anticancer Drug Delivery

Exosomes are biological nanovesicles that participate in intercellular communication by transferring biologically active chemical compounds (proteins, microRNA, mRNA, DNA, and others). Due to their small size (diameter 40-100 nm) and high biological compatibility, exosomes are promising delivery tools in personalized therapy. Because artificial exosome synthesis methods are not developed yet, the urgent task is to develop an effective and safe way to obtain exosomes from natural sources. Milk is the only exosome-containing biological fluid that is commercially available. In this regard, milk exosomes are unique and promising candidates for new therapeutic approaches to treating various diseases, including cancer. The appearance of side effects during the use of cytotoxic and cytostatic agents is among the main problems in cancer chemotherapy. According to this, the targeted delivery of chemotherapeutic agents can be a potential solution to the toxic effect of chemotherapy. The ability of milk exosomes to carry out biologically active substances to the cell makes them promising tools for oral delivery of chemotherapeutic agents. This review is devoted to the methods of milk exosome isolation, their biological components, and prospects for their use in cancer treatment.

The Potential of Milk-Derived Exosomes for Drug Delivery

BACKGROUND

Exosomes, one of the extracellular vesicles, are widely present in all biological fluids and play an important role in intercellular communication. Due to their hydrophobic lipid bilayer and aqueous hydrophilic core structure, they are considered a possible alternative to liposome drug delivery systems. Not only do they protect the cargo like liposomes during delivery, but they are also less toxic and better tolerated. However, due to the lack of sources and methods for obtaining enough exosomes, the therapeutic application of exosomes as drug carriers is limited.

METHODS

A literature search was performed using the ScienceDirect and PubMed electronic databases to obtain information from published literature on milk exosomes related to drug delivery.

RESULTS

Here, we briefly reviewed the current knowledge of exosomes, expounded the advantages of milk-derived exosomes over other delivery vectors, including higher yield, the oral delivery characteristic and additional therapeutic benefits. The purification and drug loading methods of milk exosomes, and the current application of milk exosomes were also introduced.

CONCLUSION

The emergence of milk-derived exosomes is expected to break through the limitations of exosomes as therapeutic carriers of drugs. We hope to raise awareness of the therapeutic potential of milk-derived exosomes as a new drug delivery system.

Extracellular vesicles in Inflammatory Skin Disorders: from Pathophysiology to Treatment

Extracellular vesicles (EVs), naturally secreted by almost all known cell types into extracellular space, can transfer their bioactive cargos of nucleic acids and proteins to recipient cells, mediating cell-cell communication. Thus, they participate in many pathogenic processes including immune regulation, cell proliferation and differentiation, cell death, angiogenesis, among others. Cumulative evidence has shown the important regulatory effects of EVs on the initiation and progression of inflammation, autoimmunity, and cancer. In dermatology, recent studies indicate that EVs play key immunomodulatory roles in inflammatory skin disorders, including psoriasis, atopic dermatitis, lichen planus, bullous pemphigoid, systemic lupus erythematosus, and wound healing. Importantly, EVs can be used as biomarkers of pathophysiological states and/or therapeutic agents, both as carriers of drugs or even as a drug by themselves. In this review, we will summarize current research advances of EVs from different cells and their implications in inflammatory skin disorders, and further discuss their future applications, updated techniques, and challenges in clinical translational medicine.

Echogenic Exosomes as ultrasound contrast agents

Exosomes are naturally secreted extracellular bilayer vesicles (diameter 40-130 nm), which have recently been found to play a critical role in cell-to-cell communication and biomolecule delivery. Their unique characteristics-stability, permeability, biocompatibility and low immunogenicity-have made them a prime candidate for use in delivering cancer therapeutics and other natural products. Here we present the first ever report of echogenic exosomes, which combine the benefits of the acoustic responsiveness of traditional microbubbles with the non-immunogenic and small-size morphology of exosomes. Microbubbles, although effective as ultrasound contrast agents, are restricted to intravascular usage due to their large size. In the current study, we have rendered bovine milk-derived exosomes echogenic by freeze drying them in the presence of mannitol. Ultrasound imaging and direct measurement of linear and nonlinear scattered responses were used to investigate the echogenicity and stability of the prepared exosomes. A commercial scanner registered enhancement (28.9% at 40 MHz) in the brightness of ultrasound images in presence of echogenic exosomes at 5 mg/mL. The exosomes also showed significant linear and nonlinear scattered responses-11 dB enhancement in fundamental, 8.5 dB in subharmonic and 3.5 dB in second harmonic all at 40 μg/mL concentration. Echogenic exosomes injected into the tail vein of mice and the synovial fluid of rats resulted in significantly higher brightness-as much as 300%-of the ultrasound images, showing their promise in a variety of in vivo applications. The echogenic exosomes, with their large-scale extractability from bovine milk, lack of toxicity and minimal immunogenic response, successfully served as ultrasound contrast agents in this study and offer an exciting possibility to act as an effective ultrasound responsive drug delivery system.

Bovine Milk Extracellular Vesicles Are Osteoprotective by Increasing Osteocyte Numbers and Targeting RANKL/OPG System in Experimental Models of Bone Loss

Studying effects of milk components on bone may have a clinical impact as milk is highly associated with bone maintenance, and clinical studies provided controversial associations with dairy consumption. We aimed to evaluate the impact of milk extracellular vesicles (mEVs) on the dynamics of bone loss in mice. MEVs are nanoparticles containing proteins, mRNA and microRNA, and were supplemented into the drinking water of mice, either receiving diet-induced obesity or ovariectomy (OVX). Mice receiving mEVs were protected from the bone loss caused by diet-induced obesity. In a more severe model of bone loss, OVX, higher osteoclast numbers in the femur were found, which were lowered by mEV treatment. Additionally, the osteoclastogenic potential of bone marrow-derived precursor cells was lowered in mEV-treated mice. The reduced stiffness in the femur of OVX mice was consequently reversed by mEV treatment, accompanied by improvement in the bone microarchitecture. In general, the RANKL/OPG ratio increased systemically and locally in both models and was rescued by mEV treatment. The number of osteocytes, as primary regulators of the RANKL/OPG system, raised in the femur of the OVX mEVs-treated group compared to OVX non-treated mice. Also, the osteocyte cell line treated with mEVs demonstrated a lowered RANKL/OPG ratio. Thus, mEVs showed systemic and local osteoprotective properties in two mouse models of bone loss reflected in reduced osteoclast presence. Data reveal mEV potential in bone modulation, acting via osteocyte enhancement and RANKL/OPG regulation. We suggest that mEVs could be a therapeutic candidate for the treatment of bone loss.

Specific and Non-Invasive Fluorescent Labelling of Extracellular Vesicles for Evaluation of Intracellular Processing by Intestinal Epithelial Cells

The presence of extracellular vesicles (EVs) in milk has gained interest due to their capacity to modulate the infant’s intestinal and immune system. Studies suggest that milk EVs are enriched in immune-modulating proteins and miRNA, highlighting their possible health benefits to infants. To assess uptake of milk EVs by intestinal epithelial cells, a method was developed using labelling of isolated EVs with fluorophore-conjugated lactadherin. Lactadherin is a generic and validated EV marker, which enables an effective labelling of phosphatidylserine (PS) exposing EVs. Labelled EVs could effectively be used to describe a dose- and time-dependent uptake into the intestinal epithelial Caco-2 cell line. Additionally, fluorescence microscopy was employed to show that EVs colocalize with endosomal markers and lysosomes, indicating that EVs are taken up via general endocytotic mechanisms. Collectively, a method to specifically label isolated EVs is presented and employed to study the uptake of milk EVs by intestinal epithelial cells.

MicroRNA Milk Exosomes: From Cellular Regulator to Genomic Marker

Recent advances in ruminants' milk-derived exosomes (EXO) have indicated a role of microRNAs (miRNAs) in cell-to-cell communication in dairy ruminants. The miRNAs EXO retain peculiar mechanisms of uptake from recipient cells, which enables the selective delivery of cargos, with a specific regulation of target genes. Although many studies have been published on the miRNAs contained in milk, less information is available on the role of miRNAs EXO, which are considered stable over time and resistant to digestion and milk processing. Several miRNAs EXO have been implicated in the cellular signaling pathway, as in the regulation of immune response. Moreover, they exert epigenetic control, as extenuating the expression of DNA methyltransferase 1. However, the study of miRNAs EXO is still challenging due to the difficulty of isolating EXO. In fact, there are not agreed protocols, and different methods, often time-consuming, are used, making it difficult to routinely process a large number of samples. The regulation of cell functions in mammary glands by miRNAs EXO, and their applications as genomic markers in livestock, is presented.

Isolating Multiple Extracellular Vesicles Subsets, Including Exosomes and Membrane Vesicles, from Bovine Milk Using Sodium Citrate and Differential Ultracentrifugation

Milk is a complex fluid that contains various types of proteins and extracellular vesicles (EVs). Some proteins can mingle with EVs, and interfere with their isolation. Among these proteins, caseins form micelles of a size comparable to milk EVs, and can thus be co-isolated with EVs. Preliminary steps that affect milk are crucial for EV isolation and impact the purity and abundance of isolated EVs. In the course of our previous works on cow's milk EVs, we found that sodium citrate (1% final), which is a biocompatible reagent capable of breaking down casein micelles into 40-nm monomers, allowed the isolation of high quantities of EVs with low coprecipitation of caseins or other contaminating proteins. Using this protocol, we successfully separated different EV subsets, characterized in depth their morphology, protein content and small RNA enrichment patterns. We were also able to describe their biological function in a mouse model of intestinal inflammation. We, hereby, detail the differential ultracentrifugation procedure that leads to high quantify, medium specificity, isolation of different milk EV subsets from the same sample. More specifically, we highlight the use of sodium citrate as a standardized approach to isolate and study milk EVs and its potential for isolation techniques other than differential ultracentrifugation.

Milk-Derived Extracellular Vesicles in Inter-Organism, Cross-Species Communication and Drug Delivery

Milk is considered as more than a source of nutrition for infants and is a vector involved in the transfer of bioactive compounds and cells. Milk contains abundant quantities of extracellular vesicles (EVs) that may originate from multiple cellular sources. These nanosized vesicles have been well characterized and are known to carry a diverse cargo of proteins, nucleic acids, lipids and other biomolecules. Milk-derived EVs have been demonstrated to survive harsh and degrading conditions in gut, taken up by various cell types, cross biological barriers and reach peripheral tissues. The cargo carried by these dietary EVs has been suggested to have a role in cell growth, development, immune modulation and regulation. Hence, there is considerable interest in understanding the role of milk-derived EVs in mediating inter-organismal and cross-species communication. Furthermore, various attributes such as it being a natural source, as well as its abundance, scalability, economic viability and lack of unwarranted immunologic reactions, has generated significant interest in deploying milk-derived EVs for clinical applications such as drug delivery and disease therapy. In this review, the role of milk-derived EVs in inter-organismal, cross-species communication and in drug delivery is discussed.

Charge Detection Mass Spectrometry Measurements of Exosomes and other Extracellular Particles Enriched from Bovine Milk

The masses of particles in a bovine milk extracellular vesicle (EV) preparation enriched for exosomes were directly determined for the first time by charge detection mass spectrometry (CDMS). In CDMS, both the mass-to-charge ratio (m/z) and z are determined simultaneously for individual particles, enabling mass determinations for particles that are far beyond the mass limit (∼1.0 MDa) of conventional mass spectrometry (MS). Particle masses and charges span a wide range from m ∼ 2 to ∼90 MDa and z ∼ 50 to ∼1300 e (elementary charges) and are highly dependent upon the conditions used to extract and isolate the EVs. EV particles span a continuum of masses, reflecting the highly heterogeneous nature of these samples. However, evidence for unique populations of particles is obtained from correlation of the charges and masses. An analysis that uses a two-dimensional Gaussian model, provides evidence for six families of particles, four of which having masses in the range expected for exosomes. Complementary proteomics measurements and electron microscopy (EM) imaging are used to further characterize the EVs and confirm that these samples have been enriched in exosomes. The ability to characterize such extremely heterogeneous mixtures of large particles with rapid, sensitive, and high-resolution MS techniques is critical to ongoing analytical efforts to separate and purify exosomes and exosome subpopulations. Direct measurement of each particle's mass and charge is a new means of characterizing the physical and chemical properties of exosomes and other EVs.

Targeting Liver Cancer Stem Cells Using Engineered Biological Nanoparticles for the Treatment of Hepatocellular Cancer

By exploiting their biological functions, the use of biological nanoparticles such as extracellular vesicles can provide an efficient and effective approach for hepatic delivery of RNA‐based therapeutics for the treatment of liver cancers such as hepatocellular cancer (HCC). Targeting liver cancer stem cells (LCSC) within HCC provide an untapped opportunity to improve outcomes by enhancing therapeutic responses. Cells with tumor‐initiating capabilities such as LCSC can be identified by expression of markers such as epithelial cell adhesion molecule (EpCAM) on their cell surface. EpCAM is a target of Wnt/β‐catenin signaling, a fundamental pathway in stem‐cell growth. Moreover, mutations in the β‐catenin gene are frequently observed in HCC and can be associated with constitutive activation of the Wnt/β‐catenin pathway. However, targeting these pathways for the treatment of HCC has been challenging. Using RNA nanotechnology, we developed engineered biological nanoparticles capable of specific and effective delivery of RNA therapeutics targeting β‐catenin to LCSC. Extracellular vesicles isolated from milk were loaded with small interfering RNA to β‐catenin and decorated with RNA scaffolds to incorporate RNA aptamers capable of binding to EpCAM. Cellular uptake of these EpCAM‐targeting therapeutic milk‐derived nanovesicles in vitro resulted in loss of β‐catenin expression and decreased proliferation. The uptake and therapeutic efficacy of these engineered biological nanotherapeutics was demonstrated in vivo using tumor xenograft mouse models. Conclusion: β‐catenin can be targeted directly to control the proliferation of hepatic cancer stem cells using small interfering RNA delivered using target‐specific biological nanoparticles. Application of this RNA nanotechnology–based approach to engineer biological nanotherapeutics provides a platform for developing cell‐surface molecule–directed targeted therapeutics.

A Method for the Isolation of Exosomes from Human and Bovine Milk

Scope

Milk provides a natural means of nutrient supply to infants. Exosomes are an important component of milk that are not only being studied for their promise in translational medicine but also in infant nutrition. They also play important roles in intercellular communication and immune function in mammary glands and are able to transfer their materials to the recipient. Therefore, the isolation of high-quality exosomes is an important aspect of exosome research.

Methods and Results

This study is a technical study, which provides a detailed methodology for the isolation and enrichment of exosomes from milk. In this study, we evaluate the suitability of using the exosome enrichment method that we have recently published for bovine milk, on human milk. We initially isolated extracellular vesicles from human and bovine milk on a fresh set of samples, using ultracentrifugation, and then exosomes were subsequently enriched via size exclusion chromatography (SEC). Following isolation and enrichment, exosomes from both species were characterized by particle concentration (nanoparticle tracking analysis, NTA), morphology (transmission electron microscopy, TEM), and the presence of exosomal markers (immunoblotting and mass spectrometry using information dependant acquisition (IDA)). The key exosomal characteristics of spherical/donut-shaped morphology, the presence of exosomal markers, e.g., FLOT-1 and the tetraspanins, CD9 and CD81), and particle concentration were confirmed in both human and bovine milk exosomes.

Conclusion

We conclude that our robust exosome enrichment method, previously published for bovine milk, is suitable for use on human milk.

Extracellular Vesicles-Connecting Kingdoms

It is known that extracellular vesicles (EVs) are shed from cells of almost every type of cell or organism, showing their ubiquity in all empires of life. EVs are defined as naturally released particles from cells, delimited by a lipid bilayer, and cannot replicate. These nano- to micrometer scaled spheres shuttle a set of bioactive molecules. EVs are of great interest as vehicles for drug targeting and in fundamental biological research, but in vitro culture of animal cells usually achieves only small yields. The exploration of other biological kingdoms promises comprehensive knowledge on EVs broadening the opportunities for basic understanding and therapeutic use. Thus, plants might be sustainable biofactories producing nontoxic and highly specific nanovectors, whereas bacterial and fungal EVs are promising vaccines for the prevention of infectious diseases. Importantly, EVs from different eukaryotic and prokaryotic kingdoms are involved in many processes including host-pathogen interactions, spreading of resistances, and plant diseases. More extensive knowledge of inter-species and interkingdom regulation could provide advantages for preventing and treating pests and pathogens. In this review, we present a comprehensive overview of EVs derived from eukaryota and prokaryota and we discuss how better understanding of their intercommunication role provides opportunities for both fundamental and applied biology.

Concentrates of two subsets of extracellular vesicles from cow's milk modulate symptoms and inflammation in experimental colitis

Extracellular vesicles (EVs) are involved in cell-to-cell communication and modulation of numerous physiological and pathological processes. EVs are found in large quantities in milk and contain several inflammation- and immunity-modulating proteins and microRNAs, through which they exert beneficial effects in several inflammatory disease models. Here, we investigated the effects of two EV subsets, concentrated from commercial cow's milk, on a murine model of colitis induced with dextran sodium sulfate (DSS). P35K EVs, isolated by ultracentrifugation at 35,000 g, and P100K EVs, isolated at 100,000 g, were previously characterized and administered by gavage to healthy and DSS-treated mice. P35K EVs and, to a lesser extent, P100K EVs improved several outcomes associated to DSS-induced colitis, modulated the gut microbiota, restored intestinal impermeability and replenished mucin secretion. Also, P35K EVs modulated innate immunity, while P100K EVs decreased inflammation through the downregulation of colitis-associated microRNAs, especially miR-125b, associated with a higher expression of the NFκB inhibitor TNFAIP3 (A20). These results suggest that different milk EV subsets may improve colitis outcomes through different, and possibly complementary, mechanisms. Further unveiling of these mechanisms might offer new opportunities for improving the life of patients with colitis and be of importance for milk processing, infant milk formulation and general public health.

Acidification effects on isolation of extracellular vesicles from bovine milk

Bovine milk extracellular vesicles (EVs) attract research interest as carriers of biologically active cargo including miRNA from donor to recipient cells to facilitate intercellular communication. Since toxicity of edible milk seems to be negligible, milk EVs are applicable to use for therapeutics in human medicine. Casein separation is an important step in obtaining pure EVs from milk, and recent studies reported that adding hydrochloric acid (HCl) and acetic acid (AA) to milk accelerates casein aggregation and precipitation to facilitate EV isolation and purification; however, the effects of acidification on EVs remain unclear. In this study, we evaluated the acidification effects on milk-derived EVs with that by standard ultracentrifugation (UC). We separated casein from milk by either UC method or treatment with HCl or AA, followed by evaluation of EVs in milk serum (whey) by transmission electron microcopy (TEM), spectrophotometry, and tunable resistive pulse sensing analysis to determine EVs morphology, protein concentration, and EVs size and concentration, respectively. Moreover, we used anti-CD9, -CD63, -CD81, -MFG-E8, -HSP70, and -Alix antibodies for the detection of EVs surface and internal marker proteins by western blot (WB). Morphological features of EVs were spherical shape and similar structure was observed in isolated EVs by TEM. However, some of the EVs isolated by HCl and AA had shown rough surface. Although protein concentration was higher in whey obtained by UC, EV concentration was significantly higher in whey following acid treatment. Moreover, although all of the targeted EVs-marker-proteins were detected by WB, HCl- or AA-treatments partially degraded CD9 and CD81. These findings indicated that acid treatment successfully separated casein from milk to allow efficient EV isolation and purification but resulted in partial degradation of EV-surface proteins. Our results suggest that following acid treatment, appropriate EV-surface-marker antibodies should be used for accurate assess the obtained EVs for downstream applications. This study describes the acidification effects on EVs isolated from bovine milk for the first time.

A review on protein markers of exosome from different bio-resources and the antibodies used for characterization

Exosomes are small membrane vesicles (ranging from 30 nm to 150 nm), secreted by different cell types upon fusion of multivesicular bodies (MVB) to the cell plasma membrane under a variety of normal and pathological conditions. Through transferring their cargos such as proteins, lipids and nucleic acids from donor cells to recipient cells, exosomes play a crucial role in cell-to-cell communication. Due to their presence in most body fluids (such as blood, breast milk, saliva, urine, bile, pancreatic juice, cerebrospinal and peritoneal fluids), and their role in carrying bioactive molecules from the cells of origin, exosomes have attracted great interest in their diagnostic and prognostic value for various diseases and therapeutic approaches. Although a large body of literature has documented the importance of exosomes over the past decade, there is no article systematically summarizing protein markers of exosome from different resources and the antibodies that are suited to characterize exosomes. In this review, we briefly summarize the exosome marker proteins, exosomal biomarkers for different diseases, and the antibodies suitable for different bio-resources exosomes characterization.

Milk MicroRNAs in Health and Disease

MicroRNAs are small noncoding RNAs responsible for regulating 40% to 60% of gene expression at the posttranscriptional level. The discovery of circulating microRNAs in several biological fluids opened the path for their study as biomarkers and long-range cell-to-cell communication mediators. Their transfer between individuals in the case of blood transfusion, for example, and their high enrichment in milk have sparked the interest for microRNA transfer through diet, especially from mothers to infants during breastfeeding. The extension of such paradigm led to the study of milk microRNAs in the case of cow or goat milk consumption in adults. Here we provide a comprehensive critical review of the key findings surrounding milk microRNAs in human, cow, and goat milk among other species. We discuss the data on their biological properties, their use as disease biomarkers, their transfer between individuals or species, and their putative or verified functions in health and disease of infants and adult consumers. This work is based on all the literature available and integrates all the results, theories, debates, and validation studies available so far on milk microRNAs and related areas of investigations. We critically discuss the limitations and outline future aspects and avenues to explore in this rapidly growing field of research that could impact public health through infant milk formulations or new therapies. We hope that this comprehensive review of the literature will provide insight for all teams investigating milk RNAs' biological activities and help ensure the quality of future reports.

Exosomes: The next generation of endogenous nanomaterials for advanced drug delivery and therapy

Development of functional nanomaterials is of great importance and significance for advanced drug delivery and therapy. Nevertheless, exogenous nanomaterials have a great ability to induce undesired immune responses and nano-protein interactions, which may result in toxicity and failure of therapy. Exosomes, a kind of endogenous extracellular vesicle (40-100 nm in diameter), are considered as a new generation of a natural nanoscale delivery system. Exosomes secreted by different types of cells carry different signal molecules (such as RNAs and proteins) and thus have a great potential for targeted drug delivery and therapy. Herein, we provide comprehensive understanding of the properties and applications of exosomes, including their biogenesis, biofunctions, isolation, purification, and drug loading, and typical examples in drug delivery and therapy. Furthermore, their advantages compared to other nanoparticles and potential in tumor immunotherapy are also discussed. STATEMENT OF SIGNIFICANCE: Exosomes, a kind of endogenous extracellular vesicle, have emerged as a novel and attractive endogenous nanomaterial for advanced drug delivery and targeted therapy. Exosomes are secreted by many types of cells and carry some unique signals obtained from their parental cells. Furthermore, the liposome-like structure allows exosomes to load various drugs. Hence, the potential of exosomes in drug delivery, tumor targeted therapy, and immunotherapy has been investigated in recent years. On the basis of their endogenous features and multifunctional properties, exosomes are of great significance and interest for the development of future medicine and pharmaceuticals.

Extracellular Vesicles as Vehicles for the Delivery of Food Bioactives

The nutritional value of food can be improved by the addition of bioactive compounds. However, most of these favorable food additives demonstrate low bioavailability because of their limited stability, solubility, and structural transformations upon digestion and absorption. One strategy to combat these limitations is to integrate bioactives into nanoparticles, although the mostly used artificial materials may result in immune system activation and fast clearing times. Therefore, novel, more biocompatible delivery systems are required. Extracellular vesicles are communication tools designed by evolution to transfer information between cells, organs, and whole organisms. Hence, these vesicles offer enormous potential for targeted bioactive compound delivery.

Latest advances in extracellular vesicles: from bench to bedside

Extracellular vesicles (EVs) are small membraned vesicles and approximately 50-150 nm in diameter. Almost all of the type of cells releases the EVs and circulates in the body fluids. EVs contain multiple functional components, such as mRNAs, microRNAs (miRNAs), DNAs, and proteins, which can be transferred to the recipient cells, resulting in phenotypic changes. Recently, EV research has focused on their potential as a drug delivery vehicle and in targeted therapy against specific molecules. Moreover, some surface proteins are specific to particular diseases, and therefore, EVs also have promise as biomarkers. In this concise review, we summarize the latest research focused on EVs, which have the potential to become a promising drug delivery method, biomarker, and new therapeutic target for improving the outcomes of cancer patients.