Towards analyzing the potential of exosomes to deliver microRNA therapeutics

Surface Engineering of HEK293 Cell-Derived Extracellular Vesicles for Improved Pharmacokinetic Profile and Targeted Delivery of IL-12 for the Treatment of Hepatocellular Carcinoma

Background

Extracellular vesicles (EVs) are considered a promising drug delivery platform. Naïve EVs face numerous issues that limit their applications, such as fast clearance, hepatic accumulations, and a lack of target-specific tropism. We aimed to explore a series of surface engineering approaches to: 1) reduce the non-specific adhesion of EVs, and 2) improve their enrichment in the target tissue. As a proof-of-concept, we investigated the therapeutic potentials of a multi-modal EVs system carrying a tumor-specific nanobody and the immuno-stimulant interleukin-12 (IL12) using in vivo models of hepatocellular carcinoma.

Methods

The major cell adhesion molecule on the HEK293-derived EVs, integrin β1 (ITGB1), was knocked out (KO) by CRISPR/Cas9-mediated gene editing, followed by deglycosylation to generate ITGB1^-Deg EVs for the subsequent pharmacokinetic and biodistribution analyses. ITGB1^-Deg EVs were further loaded with glypican-3 (GPC3)-specific nanobody (HN3) and mouse single-chain IL12 (mscIL12) to generate ITGB1^-mscIL12⁺HN3⁺Deg EVs, for evaluation of tumor tropism and therapeutic potential in a mice model of hepatocellular carcinoma.

Results

Removal of ITGB1 led to the broad suppression of integrins on the EVs surface, resulting in a decrease in cellular uptake. Deglycosylation of ITGB1^- EVs gave rise to inhibition of the EVs uptake by activated RAW264.7 cells. ITGB1 removal did not significantly alter the pharmacokinetic behaviors of HEK293-EVs, whereas the ITGB1^-Deg EVs exhibited enhanced systemic exposure with reduced hepatic accumulation. Loading of HN3 conferred the ITGB1^-Deg EVs with tumor-specific tropism for both subcutaneous and metastasized tumors in mice. The ITGB1^-mscIL12⁺HN3⁺Deg EVs activated mouse splenocytes with high potency. Systemic administration of the EVs with the equivalent dose of 1.5µg/kg of exosomal IL12 achieved satisfactory tumor growth inhibition and good tolerability.

Conclusion

The combinatorial approach of EVs surface engineering conferred HEK293-EVs with reduced non-specific clearance and enhanced tumor targeting efficacy, which constituted an efficient delivery platform for critical cancer therapeutics like IL12.

Hybrid exosomes, exosome-like nanovesicles and engineered exosomes for therapeutic applications

Exosomes are endosome-derived nanovesicles involved in cellular communication. They are natural nanocarriers secreted by various cells, making them suitable candidates for diverse drug delivery and therapeutic applications from a material standpoint. They have a phospholipid bilayer decorated with functional molecules and an enclosed parental matrix, which has attracted interest in developing designer/hybrid engineered exosome nanocarriers. The structural versatility of exosomes allows the modification of their original configuration using various methods, including genetic engineering, chemical procedures, physical techniques, and microfluidic technology, to load exosomes with additional cargo for expanded biomedical applications. Exosomes show enormous potential for overcoming the limitations of conventional nanoparticle-based techniques in targeted therapy. This review highlights the exosome sources, characteristics, state of the art in the field of hybrid exosomes, exosome-like nanovesicles and engineered exosomes as potential cargo delivery vehicles for therapeutic applications.

Identification of Circulating Exosomal microRNAs Associated with Radioiodine Refractory in Papillary Thyroid Carcinoma

Papillary thyroid carcinoma (PTC) has a favorable prognosis, but a fraction of cases show progressive behaviors, becoming radioiodine refractory (RAIR) PTC. To explore circulating exosomal microRNAs (miRNAs) associated with RAIR PTC, the miRNA profiles in exosomes from parental and induced RAIR cell lines were firstly identified with a next-generation sequencing technique. The Na⁺/I^- symporter (NIS) related miRNAs were then validated by quantitative real-time PCR (qRT-PCR) in plasma of PTC patients with non-¹³¹I-avid metastases and those with ¹³¹I-avid metastases. The regulation of exosomal miRNAs on NIS were also verified. We identified that miR-1296-5p, upregulation in exosomes from RAIR cell lines, and the plasma of patients with RAIR PTC achieved the largest areas under the curve (AUC) of 0.911 and that it is an independent risk factor for RAIR PTC. In addition, miR-1296-5p was abundantly detected in the tissue of RAIR PTC and can directly target downstream gene of NIS. Taken together, our findings suggested that circulating exosomal miRNAs, particularly miR-1296-5p, may be involved in the pathogenesis of RAIR PTC by directly targeting NIS.

Exosomes─Nature's Lipid Nanoparticles, a Rising Star in Drug Delivery and Diagnostics

Exosomes are a subgroup of nanosized extracellular vesicles enclosed by a lipid bilayer membrane and secreted by most eukaryotic cells. They represent a route of intercellular communication and participate in a wide variety of physiological and pathological processes. The biological roles of exosomes rely on their bioactive cargos, including proteins, nucleic acids, and lipids, which are delivered to target cells. Their distinctive properties─innate stability, low immunogenicity, biocompatibility, and good biomembrane penetration capacity─allow them to function as superior natural nanocarriers for efficient drug delivery. Another notably favorable clinical application of exosomes is in diagnostics. They hold various biomolecules from host cells, which are indicative of pathophysiological conditions; therefore, they are considered vital for biomarker discovery in clinical diagnostics. Here, we use data from the CAS Content Collection and provide a landscape overview of the current state and delineate trends in research advancement on exosome applications in therapeutics and diagnostics across time, geography, composition, cargo loading, and development pipelines. We discuss exosome composition and pathway, from their biogenesis and secretion from host cells to recipient cell uptake. We assess methods for exosome isolation and purification, their clinical applications in therapy and diagnostics, their development pipelines, the exploration goals of the companies, the assortment of diseases they aim to treat, development stages of their research, and publication trends. We hope this review will be useful for understanding the current knowledge in the field of medical applications of exosomes, in an effort to further solve the remaining challenges in fulfilling their potential.

Extracellular vesicles over adeno-associated viruses: Advantages and limitations as drug delivery platforms in precision medicine

Tissue-specific uptake and sufficient biodistribution are central goals in drug development. Crossing the blood-brain barrier (BBB) represents a major challenge in delivering therapeutics to the central nervous system (CNS). Since its discovery in the late 19th century, considerable efforts have been invested in an attempt to decipher the BBB structure complexity and plasticity. In parallel, another prevalent approach is to improve a delivery system by harnessing the biological machinery in an attempt to enhance therapeutic-agent permeability. Here, we review the advantages and limitations of using extracellular vesicles over AAV systems as a delivery system for therapy, focusing on neurodevelopmental disorders.

The Antisenescence Effect of Exosomes from Human Adipose-Derived Stem Cells on Skin Fibroblasts

Human adipose-derived stem cells (ADSCs) have become a promising therapeutic approach against skin aging. Recent studies confirm that exosomes partially mediate the therapeutic effect of stem cells. This study successfully isolated exosomes from the ADSC culture medium and discovered that ADSC-derived exosomes (ADSC-Exos) could alleviate human dermal fibroblast (HDF) senescence and stimulate HDF migration. Moreover, ADSC-Exos increased the type I collagen expression level and reduced the reactive oxygen species (ROS) and senescence-associated β-galactosidase (SA-β-Gal) activity in HDFs. In addition, we demonstrated that ADSC-Exos significantly inhibited senescence-related protein expression levels of p53, p21, and p16. In conclusion, our results have revealed the antisenescence effects of ADSC-Exos on HDFs and ADSC-Exos may be a novel cell-free therapeutic tool for antiaging.

Dissecting miRNA–Gene Networks to Map Clinical Utility Roads of Pharmacogenomics-Guided Therapeutic Decisions in Cardiovascular Precision Medicine

MicroRNAs (miRNAs) create systems networks and gene-expression circuits through molecular signaling and cell interactions that contribute to health imbalance and the emergence of cardiovascular disorders (CVDs). Because the clinical phenotypes of CVD patients present a diversity in their pathophysiology and heterogeneity at the molecular level, it is essential to establish genomic signatures to delineate multifactorial correlations, and to unveil the variability seen in therapeutic intervention outcomes. The clinically validated miRNA biomarkers, along with the relevant SNPs identified, have to be suitably implemented in the clinical setting in order to enhance patient stratification capacity, to contribute to a better understanding of the underlying pathophysiological mechanisms, to guide the selection of innovative therapeutic schemes, and to identify innovative drugs and delivery systems. In this article, the miRNA–gene networks and the genomic signatures resulting from the SNPs will be analyzed as a method of highlighting specific gene-signaling circuits as sources of molecular knowledge which is relevant to CVDs. In concordance with this concept, and as a case study, the design of the clinical trial GESS (NCT03150680) is referenced. The latter is presented in a manner to provide a direction for the improvement of the implementation of pharmacogenomics and precision cardiovascular medicine trials.

Proteome changes of plasma-derived extracellular vesicles in patients with myelodysplastic syndrome

Background

Extracellular vesicles are released into body fluids from the majority of, if not all, cell types. Because their secretion and specific cargo (e.g., proteins) varies according to pathology, extracellular vesicles may prove a rich source of biomarkers. However, their biological and pathophysiological functions are poorly understood in hematological malignancies.

Objective

Here, we investigated proteome changes in the exosome-rich fraction of the plasma of myelodysplastic syndrome patients and healthy donors.

Methods

Exosome-rich fraction of the plasma was isolated using ExoQuick^™: proteomes were compared and statistically processed; proteins were identified by nanoLC-MS/MS and verified using the ExoCarta and QuickGO databases. Mann-Whitney and Spearman analyses were used to statistically analyze the data. 2D western blot was used to monitor clusterin proteoforms.

Results

Statistical analyses of the data highlighted clusterin alterations as the most significant. 2D western blot showed that the clusterin changes were caused by posttranslational modifications. Moreover, there was a notable increase in the clusterin proteoform in the exosome-rich fraction of plasma of patients with more severe myelodysplastic syndrome; this corresponded with a simultaneous decrease in their plasma.

Conclusions

This specific clusterin proteoform seems to be a promising biomarker for myelodysplastic syndrome progression.

Exosomes, a New Star for Targeted Delivery

Exosomes are cell-secreted nanoparticles (generally with a size of 30–150 nm) bearing numerous biological molecules including nucleic acids, proteins and lipids, which are thought to play important roles in intercellular communication. As carriers, exosomes hold promise as advanced platforms for targeted drug/gene delivery, owing to their unique properties, such as innate stability, low immunogenicity and excellent tissue/cell penetration capacity. However, their practical applications can be limited due to insufficient targeting ability or low efficacy in some cases. In order to overcome these existing challenges, various approaches have been applied to engineer cell-derived exosomes for a higher selectivity and effectiveness. This review presents the state-of-the-art designs and applications of advanced exosome-based systems for targeted cargo delivery. By discussing experts’ opinions, we hope this review will inspire the researchers in this field to develop more practical exosomal delivery systems for clinical applications.

Exosomes Engineering and Their Roles as Therapy Delivery Tools, Therapeutic Targets, and Biomarkers

Exosomes are becoming increasingly important therapeutic biomaterials for use in a variety of therapeutic applications due to their unique characteristics, especially due to the ineffectiveness and cytotoxicity of some existing therapies and synthetic therapeutic nanocarriers. They are highly promising as carriers of drugs, genes, and other therapeutic agents that can be incorporated into their interior or onto their surface through various modification techniques to improve their targeting abilities. In addition, they are biocompatible, safe, and stable. The review focuses on different types of exosomes and methods of their preparation, including the incorporation of different kinds of cargo, especially for drug delivery purposes. In particular, their importance and effectiveness as delivery vehicles of various therapeutic agents for a variety of therapeutic applications, including different diseases and disorders such as cancer treatment, cardiovascular and neurodegenerative diseases, are emphasized. Administration routes of exosomes into the body are also included. A novelty in the article is the emphasis on global companies that are already successfully developing and testing such therapeutic biomaterials, with a focus on the most influential ones. Moreover, a comparison of the advantages and disadvantages of the various methods of exosome production is summarized for the first time.

Expedition into Exosome Biology: A Perspective of Progress from Discovery to Therapeutic Development

Exosomes are membrane-enclosed distinct cellular entities of endocytic origin that shuttle proteins and RNA molecules intercellularly for communication purposes. Their surface is embossed by a huge variety of proteins, some of which are used as diagnostic markers. Exosomes are being explored for potential drug delivery, although their therapeutic utilities are impeded by gaps in knowledge regarding their formation and function under physiological condition and by lack of methods capable of shedding light on intraluminal vesicle release at the target site. Nonetheless, exosomes offer a promising means of developing systems that enable the specific delivery of therapeutics in diseases like cancer. This review summarizes information on donor cell types, cargoes, cargo loading, routes of administration, and the engineering of exosomal surfaces for specific peptides that increase target specificity and as such, therapeutic delivery.

miR-16-5p Promotes Erythroid Maturation of Erythroleukemia Cells by Regulating Ribosome Biogenesis

miRNAs constitute a class of non-coding RNA that act as powerful epigenetic regulators in animal and plant cells. In order to identify putative tumor-suppressor miRNAs we profiled the expression of various miRNAs during differentiation of erythroleukemia cells. RNA was purified before and after differentiation induction and subjected to quantitative RT-PCR. The majority of the miRNAs tested were found upregulated in differentiated cells with miR-16-5p showing the most significant increase. Functional studies using gain- and loss-of-function constructs proposed that miR-16-5p has a role in promoting the erythroid differentiation program of murine erythroleukemia (MEL) cells. In order to identify the underlying mechanism of action, we utilized bioinformatic in-silico platforms that incorporate predictions for the genes targeted by miR-16-5p. Interestingly, ribosome constituents, as well as ribosome biogenesis factors, were overrepresented among the miR-16-5p predicted gene targets. Accordingly, biochemical experiments showed that, indeed, miR-16-5p could modulate the levels of independent ribosomal proteins, and the overall ribosomal levels in cultured cells. In conclusion, miR-16-5p is identified as a differentiation-promoting agent in erythroleukemia cells, demonstrating antiproliferative activity, likely as a result of its ability to target the ribosomal machinery and restore any imbalanced activity imposed by the malignancy and the blockade of differentiation.

A perspective on RNA interference-based therapeutics for metabolic liver diseases

Introduction: Therapeutic oligonucleotides have emerged as a promising new class of drug that could silence undruggable targets; they can potentially treat metabolic liver diseases such as nonalcoholic fatty liver disease (NAFLD), hereditary hemochromatosis and alpha 1 antitrypsin deficiency.Areas covered: This article illuminates the mechanism of action of, and drug delivery approaches for therapeutic oligonucleotides such as antisense oligonucleotides (ASOs), short interfering RNAs (siRNAs), and MicroRNAs (miRs). We reveal why the liver is the ideal organ for therapeutic oligonucleotides, discuss its unique architecture, and shed light on those susceptible molecular targets that can be modulated. We also examine preclinical and clinical data on the utility of oligonucleotides in silencing the expression of genes responsible for metabolic liver diseases.Expert opinion: The liver has numerous susceptible molecular therapeutic targets; hence, metabolic liver diseases can be treated effectively by modulating these targets via novel therapeutic oligonucleotides. Undoubtedly, these exciting developments integrate well with precision medicine progress. Specific therapeutic oligonucleotides can be designed based on the exact underlying molecular mechanism of the disease. So, there is a justification for furthering the development of therapeutic oligonucleotides for metabolic liver diseases. Safety concerns such as immunogenicity and off-target effects will however require careful monitoring.

Exosomes as Drug Delivery Systems: Endogenous Nanovehicles for Treatment of Systemic Lupus Erythematosus

Exosomes, nanometer-sized lipid-bilayer-enclosed extracellular vesicles (EVs), have attracted increasing attention due to their inherent ability to shuttle proteins, lipids and genes between cells and their natural affinity to target cells. Their intrinsic features such as stability, biocompatibility, low immunogenicity and ability to overcome biological barriers, have prompted interest in using exosomes as drug delivery vehicles, especially for gene therapy. Evidence indicates that exosomes play roles in both immune stimulation and tolerance, regulating immune signaling and inflammation. To date, exosome-based nanocarriers delivering small molecule drugs have been developed to treat many prevalent autoimmune diseases. This review highlights the key features of exosomes as drug delivery vehicles, such as therapeutic cargo, use of targeting peptide, loading method and administration route with a broad focus. In addition, we outline the current state of evidence in the field of exosome-based drug delivery systems in systemic lupus erythematosus (SLE), evaluating exosomes derived from various cell types and engineered exosomes.