Characterization of and isolation methods for plant leaf nanovesicles and small extracellular vesicles

Unveiling the potential: Extracellular vesicles from plant cell suspension cultures as a promising source

Extracellular vesicles are secreted by all eukaryotic cells and they have an important role in intercellular signaling. Plant extracellular vesicles (PEVs) are a novel area of research that has gained attention due to their potential implications in biomolecule transport and therapeutic applications. PEVs are lipid bilayer-enclosed structures that contain a diverse cargo of biomolecules such as proteins and lipids. Moreover, it is known that PEVs have a noticeable therapeutic potential for various conditions such as inflammation and oxidative stress. However, there are critical problems such as removing the endosomes and plant-derived biomolecules that decrease the standardization and therapeutic efficacy of PEVs. In our study, the aim was to characterize plant cell suspension-derived extracellular vesicles (PCSEVs) obtained from two different plant cell suspension cultures: Stevia rebaudiana and Vaccaria hispanica. These vesicles were isolated using ultrafiltration and characterized with nanoparticle tracking analysis (NTA) and atomic force microscopy (AFM). The molecular composition of PCSEVs was profiled and the cellular uptake assay was performed. Our results demonstrated that PCSEVs have a spherical shape, less than 200 nm. In the fatty acid analysis, the primary components in PCSEVs were palmitic acid, linoleic acid, and cis-vaccenic acid. The protein content of Stevia rebaudiana-derived EVs (SDEVs) was largely associated with proteins involved in extracellular structures and functions. Conversely, Vaccaria hispanica-derived EVs (HDEVs) displayed a higher presence of cytosolic proteins. These findings contribute to the understanding of PCSEVs and open up potential avenues in extracellular vesicle research, pointing to promising prospects for future innovations in various fields.

Herb Extracellular Vesicle-Chitosan-PEGylated Graphene Oxide Conjugate Delivers Estrogen Receptor α Targeting siRNA to Breast Cancer Cells

Herb-based extracellular vesicles (EV), inherently replete with bioactive proteins, RNA, lipids, and other medicinal compounds, are noncytotoxic and uniquely capable of cellular delivery to meet the ever-stringent challenges of ongoing clinical applications. EVs are abundant in nature, affordable, and scalable, but they are also incredibly fragile and stuffed with many biomolecules. To address the low drug binding abilities and poor stability of EVs, we demonstrated herb-based EVs (isolated from neem, mint, and curry leaves) conjugated with chitosan (CS) and PEGylated graphene oxide (GP) that led to their transformation into robust and efficient vectors. The designed conjugates successfully delivered estrogen receptor α (ERα1)-targeting siRNA to breast cancer MCF7 cells. Our data revealed that neem-based EV-CS-GP conjugates were most efficient in cellular siRNA delivery, which could be attributed to hyaluronic acid-mediated recognition of neem EVs by MCF7 cells via CD44 receptors. Our approach shows a futuristic direction in designing clinically viable, sustainable, nontoxic EV-based vehicles that can deliver a variety of functional siRNA cargos.

Exploring new avenues of health protection: plant-derived nanovesicles reshape microbial communities

Symbiotic microbial communities are crucial for human health, and dysbiosis is associated with various diseases. Plant-derived nanovesicles (PDNVs) have a lipid bilayer structure and contain lipids, metabolites, proteins, and RNA. They offer unique advantages in regulating microbial community homeostasis and treating diseases related to dysbiosis compared to traditional drugs. On the one hand, lipids on PDNVs serve as the primary substances that mediate specific recognition and uptake by bacteria. On the other hand, due to the multifactorial nature of PDNVs, they have the potential to enhance growth and survival of beneficial bacterial while simultaneously reducing the pathogenicity of harmful bacteria. In addition, PDNVs have the capacity to modulate bacterial metabolism, thus facilitating the establishment of a harmonious microbial equilibrium and promoting stability within the microbiota. These remarkable attributes make PDNVs a promising therapeutic approach for various conditions, including periodontitis, inflammatory bowel disease, and skin infection diseases. However, challenges such as consistency, isolation methods, and storage need to be addressed before clinical application. This review aims to explore the value of PDNVs in regulating microbial community homeostasis and provide recommendations for their use as novel therapeutic agents for health protection.

Extracellular vesicles isolated from Arabidopsis thaliana leaves reveal characteristics of mammalian exosomes

Plant-derived extracellular vesicles (EVs), containing a myriad of bioactive proteins, microRNAs, lipids, and secondary metabolites, have recently become the focus of rising interest due to their important roles in various applications. The widely accepted method for isolating plant EVs is differential ultracentrifugation plus density gradient centrifugation. However, the combination of differential ultracentrifugation and density gradient centrifugation for the isolation of plant EVs is time-consuming and labor-intensive. Hence, there is a need for more efficient methods to perform the separation of plant EVs. In this study, EVs were separated from Arabidopsis thaliana leaves by a cost-effective polyethylene glycol (PEG)-based precipitation approach. The mean size of purified Arabidopsis thaliana EVs determined by dynamic light scattering was 266 nm, which is consistent with nanoparticle tracking analysis. The size was also confirmed via transmission electron microscopy with morphology of a cup-shaped appearance which is the typical mammalian exosome's morphology. Additionally, Western blotting of the purified Arabidopsis thaliana EVs, using commercially available mammalian exosomal kits, displayed surface marker tetraspanin proteins (CD9, CD63, and CD81), and endosomal sorting complexes required for transport (ESCRT)-associated proteins (TSG101 and ALIX). This demonstrates that the purified Arabidopsis thaliana EVs reveal the typical proteins reported in mammalian exosomes.

Plant-Derived Vesicle-like Nanoparticles: The Next-Generation Drug Delivery Nanoplatforms

A wide variety of natural bioactive compounds derived from plants have demonstrated significant clinical relevance in the treatment of various diseases such as cancer, chronic disease, and inflammation. An increasing number of studies have surfaced that give credence to the potential of plant-derived vesicle-like nanoparticles (PDVLNs) as compelling candidates for a drug delivery system (DDS). PDVLNs are cost-effective production, non-toxicity and non-immunogenicity and fascinating bi-ocompatibility. In this review, we attempt to comprehensively review and consolidate the position of PDVLNs as next-generation drug delivery nanoplatforms. We aim to give a quick glance to readers of the current developments of PDVLNs, including their biogenesis, characteristic features, composition, administration routes, advantages, and application. Further, we discuss the advantages and limitations of PDVLNs. We expect that the role of PDVLNs in drug delivery will be significantly enhanced, thus positioning them as the next generation of therapeutic modalities in the foreseeable future.

Plant-derived nanovesicles offer a promising avenue for anti-aging interventions

Over the past few years, the study of plant-derived nanovesicles (PDNVs) has emerged as a hot topic of discussion and research in the scientific community. This remarkable interest stems from their potential role in facilitating intercellular communication and their unique ability to deliver biologically active components, including proteins, lipids, and miRNAs, to recipient cells. This fascinating ability to act as a molecular courier has opened up an entirely new dimension in our understanding of plant biology. The field of research focusing on the potential applications of PDNVs is still in its nascent stages. However, it has already started gaining traction due to the growing interest in its possible use in various branches of biotechnology and medicine. Their unique properties and versatile applications offer promising future research and development prospects in these fields. Despite the significant progress in our understanding, many unanswered questions and mysteries surround the mechanisms by which PDNVs function and their potential applications. There is a dire need for further extensive research to elucidate these mechanisms and explore the full potential of these fascinating vesicles. As the technology at our disposal advances and our understanding of PDNVs deepens, it is beyond doubt that PDNVs will continue to be a subject of intense research in anti-aging therapeutics. This comprehensive review is designed to delve into the fascinating and multifaceted world of PDNV-based research, particularly focusing on how these nanovesicles can be applied to anti-aging therapeutics.

The extracellular vesicle proteomes of Sorghum bicolor and Arabidopsis thaliana are partially conserved

Plant extracellular vesicles (EVs) are membrane-bound organelles involved mainly in intercellular communications and defense responses against pathogens. Recent studies have demonstrated the presence of proteins, nucleic acids including small RNAs, and lipids along with other metabolites in plant EVs. Here, we describe the isolation and characterization of EVs from sorghum (Sorghum bicolor). Nanoparticle tracking analysis, dynamic light scattering, and cryo-electron tomography showed the presence of a heterogeneous population of EVs isolated from the apoplastic wash of sorghum leaves. Cryo-electron microscopy revealed that EVs had a median size of 110 nm and distinct populations of vesicles with single or multiple lipid bilayers and low or high amounts of contents. The heterogeneity was further supported by data showing that only a subset of EVs that were stained with a membrane dye, Potomac Gold, were also stained with the membrane-permeant esterase-dependent dye, calcein acetoxymethyl ester. Proteomic analysis identified 437 proteins that were enriched in multiple EV isolations, with the majority of these also found in the EV proteome of Arabidopsis (Arabidopsis thaliana). These data suggest a partial conservation of EV contents and function between the monocot, sorghum, and a distantly related eudicot, Arabidopsis.

Anti-cancer bioactivity of sweet basil leaf derived extracellular vesicles on pancreatic cancer cells

Most living organisms secrete tiny lipid bilayer particles encapsulating various biomolecular entities, including nucleic acids and proteins. These secreted extracellular vesicles (EVs) are shown to aid in communication between cells and their environment. EVs are mainly involved in the signalling and manipulation of physiological processes. Plant EVs display similar functional activity as seen in mammalian EVs. Medicinal plants have many bioactive constituents with potential applications in cancer treatment. Particularly, Basil (Ocimum basilicum), has wide therapeutic properties including anti-inflammatory, anti-cancer, and anti-infection, among others. In this study, we focused on using EVs purified from Apoplast Washing Fluid (AWF) of Basil plant leaves as a biological therapeutic agent against cancer. Characterization of Basil EVs revealed a size range of 100-250 nm, which were later assessed for their cell uptake and apoptosis inducing abilities in pancreatic cancer cells. Basil plant EVs (BasEVs) showed a significant cytotoxic effect on pancreatic cancer cell line MIA PaCa-2 at a concentration of 80 and 160 μg/mL in cell viability, as well as clonogenic assays. Similarly, RT-PCR and western blot analysis has shown up regulation in apoptotic gene and protein expression of Bax, respectively, in BasEV treatment groups compared to untreated controls of MIA PaCa-2. Overall, our results suggest that EVs from basil plants have potent anti-cancer effects in pancreatic cancer cells and can serve as a drug delivery system, demanding an investigation into the therapeutic potential of other medicinal plant EVs.

Plant Extracellular Vesicles: Current Landscape and Future Directions

Plant cells secrete membrane-enclosed micrometer- and nanometer-sized vesicles that, similarly to the extracellular vesicles (EVs) released by mammalian or bacterial cells, carry a complex molecular cargo of proteins, nucleic acids, lipids, and primary and secondary metabolites. While it is technically complicated to isolate EVs from whole plants or their tissues, in vitro plant cell cultures provide excellent model systems for their study. Plant EVs have been isolated from the conditioned culture media of plant cell, pollen, hairy root, and protoplast cultures, and recent studies have gathered important structural and biological data that provide a framework to decipher their physiological roles and unveil previously unacknowledged links to their diverse biological functions. The primary function of plant EVs seems to be in the secretion that underlies cell growth and morphogenesis, cell wall composition, and cell-cell communication processes. Besides their physiological functions, plant EVs may participate in defence mechanisms against different plant pathogens, including fungi, viruses, and bacteria. Whereas edible and medicinal-plant-derived nanovesicles isolated from homogenised plant materials ex vivo are widely studied and exploited, today, plant EV research is still in its infancy. This review, for the first time, highlights the different in vitro sources that have been used to isolate plant EVs, together with the structural and biological studies that investigate the molecular cargo, and pinpoints the possible role of plant EVs as mediators in plant-pathogen interactions, which may contribute to opening up new scenarios for agricultural applications, biotechnology, and innovative strategies for plant disease management.

Therapeutic potential and pharmacological significance of extracellular vesicles derived from traditional medicinal plants

Medicinal plants are the primary sources for the discovery of novel medicines and the basis of ethnopharmacological research. While existing studies mainly focus on the chemical compounds, there is little research about the functions of other contents in medicinal plants. Extracellular vesicles (EVs) are functionally active, nanoscale, membrane-bound vesicles secreted by almost all eukaryotic cells. Intriguingly, plant-derived extracellular vesicles (PDEVs) also have been implicated to play an important role in therapeutic application. PDEVs were reported to have physical and chemical properties similar to mammalian EVs, which are rich in lipids, proteins, nucleic acids, and pharmacologically active compounds. Besides these properties, PDEVs also exhibit unique advantages, especially intrinsic bioactivity, high stability, and easy absorption. PDEVs were found to be transferred into recipient cells and significantly affect their biological process involved in many diseases, such as inflammation and tumors. PDEVs also could offer unique morphological and compositional characteristics as natural nanocarriers by innately shuttling bioactive lipids, RNA, proteins, and other pharmacologically active substances. In addition, PDEVs could effectively encapsulate hydrophobic and hydrophilic chemicals, remain stable, and cross stringent biological barriers. Thus, this study focuses on the pharmacological action and mechanisms of PDEVs in therapeutic applications. We also systemically deal with facets of PDEVs, ranging from their isolation to composition, biological functions, and biotherapeutic roles. Efforts are also made to elucidate recent advances in re-engineering PDEVs applied as stable, effective, and non-immunogenic therapeutic applications to meet the ever-stringent demands. Considering its unique advantages, these studies not only provide relevant scientific evidence on therapeutic applications but could also replenish and inherit precious cultural heritage.

Isolation and Characterization of Extracellular Vesicles from Arabidopsis thaliana Cell Culture and Investigation of the Specificities of Their Biogenesis

Over recent years, extracellular vesicles (EVs), commonly termed exosomes, have gained prominence for their potential as natural nanocarriers. It has now been recognized that plants also secrete EVs. Despite this discovery, knowledge about EV biogenesis in plant cell cultures remains limited. In our study, we have isolated and meticulously characterized EVs from the callus culture of the model plant, Arabidopsis thaliana. Our findings indicate that the abundance of EVs in calli was less than that in the plant's apoplastic fluid. This difference was associated with the transcriptional downregulation of the endosomal sorting complex required for transport (ESCRT) genes in the calli cells. While salicylic acid increased the expression of ESCRT components, it did not enhance EV production. Notably, EVs from calli contained proteins essential for cell wall biogenesis and defense mechanisms, as well as microRNAs consistent with those found in intact plants. This suggests that plant cell cultures could serve as a feasible source of EVs that reflect the characteristics of the parent plant species. However, further research is essential to determine the optimal conditions for efficient EV production in these cultured cells.

Plant exosome nanovesicles (PENs): green delivery platforms

Natural plants have been attracting increasing attention in biomedical research due to their numerous benefits. Plant exosome-derived vesicles, some of the plant's components, are small nanoscale vesicles secreted by plant cells. These vesicles are rich in bioactive substances and play significant roles in intercellular communication, information transfer, and maintaining homeostasis in organisms. They also hold promise for treating diseases, and their vesicular structures make them suitable carriers for drug delivery, with large-scale production feasible. Therefore, this paper aims to provide an overview of nanovesicles from different plant sources and their extraction methods. We also outline the biological activities of nanovesicles, including their anti-inflammatory, anti-viral, and anti-tumor properties, and systematically introduce their applications in drug delivery. These applications include transdermal delivery, targeted drug delivery, gene delivery, and their potential use in the modern food industry. This review provides new ideas and methods for future research on plant exosomes, including their empowerment by artificial intelligence and gene editing, as well as their potential application in the biomedicine, food, and agriculture industries.

Plant and mammalian-derived extracellular vesicles: a new therapeutic approach for the future

Background: In recent years, extracellular vesicles have been recognized as important mediators of intercellular communication through the transfer of active biomolecules (proteins, lipids, and nucleic acids) across the plant and animal kingdoms and have considerable roles in several physiological and pathological mechanisms, showing great promise as new therapeutic strategies for a variety of pathologies. Methods: In this study, we carefully reviewed the numerous articles published over the last few decades on the general knowledge of extracellular vesicles, their application in the therapy of various pathologies, and their prospects as an approach for the future. Results: The recent discovery and characterization of extracellular vesicles (EVs) of diverse origins and biogenesis have altered the current paradigm of intercellular communication, opening up new diagnostic and therapeutic perspectives. Research into these EVs released by plant and mammalian cells has revealed their involvement in a number of physiological and pathological mechanisms, such as embryonic development, immune response, tissue regeneration, and cancer. They are also being studied as potential biomarkers for disease diagnosis and vectors for drug delivery. Conclusion: Nanovesicles represent powerful tools for intercellular communication and the transfer of bioactive molecules. Their molecular composition and functions can vary according to their origin (plant and mammalian), so their formation, composition, and biological roles open the way to therapeutic applications in a variety of pathologies, which is arousing growing interest in the scientific community. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT03608631.

Plant-Derived Exosome-Like Nanovesicles: Current Progress and Prospects

Exosomes are small extracellular vesicles, ranging in size from 30-150nm, which can be derived from various types of cells. In recent years, mammalian-derived exosomes have been extensively studied and found to play a crucial role in regulating intercellular communication, thereby influencing the development and progression of numerous diseases. Traditional Chinese medicine has employed plant-based remedies for thousands of years, and an increasing body of evidence suggests that plant-derived exosome-like nanovesicles (PELNs) share similarities with mammalian-derived exosomes in terms of their structure and function. In this review, we provide an overview of recent advances in the study of PELNs and their potential implications for human health. Specifically, we summarize the roles of PELNs in respiratory, digestive, circulatory, and other diseases. Furthermore, we have extensively investigated the potential shortcomings and challenges in current research regarding the mechanism of action, safety, administration routes, isolation and extraction methods, characterization and identification techniques, as well as drug-loading capabilities. Based on these considerations, we propose recommendations for future research directions. Overall, our review highlights the potential of PELNs as a promising area of research, with broad implications for the treatment of human diseases. We anticipate continued interest in this area and hope that our summary of recent findings will stimulate further exploration into the implications of PELNs for human health.

An enzyme-based system for extraction of small extracellular vesicles from plants

Plant-derived nanovesicles (NVs) and extracellular vesicles (EVs) are the next generation of nanocarrier platforms for biotherapeutics and drug delivery. EVs exist not only in the extracellular space, but also within the cell wall. Due to the limitations of existing isolation methods, the EVs extraction efficiency is low, and a large amount of plant material is wasted, which is of concern for rare and expensive medicinal plants. We proposed and validated a novel method for isolation of plant EVs by enzyme degradation of the plant cell wall to release the EVs. The released EVs can easily be collected. The new method was used for extraction of EVs from the roots of Morinda officinalis (MOEVs). For comparison, nanoparticles from the roots (MONVs) were extracted using the grinding method. The new method yielded a greater amount of MOEVs, and the vesicles had a smaller diameter compared to MONVs. Both MOEVs and MONVs were readily absorbed by endothelial cells without cytotoxic effect and promoted the expression of miR-155. The promotion of miR-155 by MOEVs was dose-dependent. More importantly, we found that MOEVs and MONVs were enriched toward bone tissue. These results support our hypothesis that EVs in plants could be efficiently extracted by enzymatic cell wall digestion and confirm the potential of MOEVs as therapeutic agents and drug carriers.

Plant-derived exosomal nanoparticles: potential therapeutic for inflammatory bowel disease

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic autoimmune disorder characterized by inflammation. However, currently available disease-modifying anti-IBD drugs exhibit limited efficacy in IBD therapy. Furthermore, existing therapeutic approaches provide only partial relief from IBD symptoms and are associated with certain side effects. In recent years, a novel category of nanoscale membrane vesicles, known as plant-derived exosome-like nanoparticles (PDENs), has been identified in edible plants. These PDENs are abundant in bioactive lipids, proteins, microRNAs, and other pharmacologically active compounds. Notably, PDENs possess immunomodulatory, antitumor, regenerative, and anti-inflammatory properties, making them particularly promising for the treatment of intestinal diseases. Moreover, PDENs can be engineered as targeted delivery systems for the efficient transport of chemical or nucleic acid drugs to the site of intestinal inflammation. In the present study, we provided an overview of PDENs, including their biogenesis, extraction, purification, and construction strategies, and elucidated their physiological functions and therapeutic effects on IBD. Additionally, we summarized the applications and potential of PDENs in IBD treatment while highlighting the future directions and challenges in the field of emerging nanotherapeutics for IBD therapy.

Plant Exosome-like Nanovesicles and Their Role in the Innovative Delivery of RNA Therapeutics

Exosomes are single membrane-bound spheres released from cells carrying complex cargoes, including lipids, proteins, and nucleic acids. Exosomes transfer specific cargoes from donor to acceptor cells, playing important roles in cell-to-cell communication. Current studies have reported that plant exosomes are prominent in transferring small RNA between host and pathogens in a cross-kingdom manner. Plant exosomes are excellent RNA interference (RNAi) delivery agents with similar physical and chemical properties to mammalian exosomes and have potential applications in therapeutic delivery systems. Recent data have suggested that plant exosome-like nanovesicles (PENVs) and artificial PENV-derived nano-vectors (APNVs) are beneficial for delivering therapeutic small RNA in mammalian systems and exhibit excellent competitiveness in future clinical applications. This review features their preparation methods, composition, roles in small RNA delivery for health functionalities, and their potency as functional nanomedicine.

Plant-Derived Vesicle-Like Nanoparticles as Promising Biotherapeutic Tools: Present and Future

Extracellular vesicles (EVs) are heterogeneous, phospholipid bilayer-enclosed biological particles that regulate cell communication by molecular cargo delivery and surface signaling. EVs are secreted by almost all living cells, including plant cells. Plant-derived vesicle-like nanoparticles (PDVLNs) is a generic term referring to vesicle-like nanostructure particles isolated from plants. Their low immunogenicity and wide availability make PDVLNs safer and more economical to be developed as therapeutic agents and drug carriers. Accumulating evidence indicates the key roles of PDVLNs in regulating interkingdom crosstalk between humans and plants. PDVLNs are capable of entering the human-body systemand delivering effector molecules to cells that modulate cell-signaling pathways. PDVLNs released by or obtained from plants thus have great influenceon human health and diseases. In this review, the biogenesis, detailed preparation methods, various physical and biochemical characteristics, biosafety, and preservation of PDVLNs are introduced, along with how these characteristics pertain to their biosafety and preservability. The potential applications of PDVLNs on different plant and mammalian diseases and PDVLN research standardization are then systematically discussed.

Oral Treatment with Plant-Derived Exosomes Restores Redox Balance in H2O2-Treated Mice

Plant-derived exosomes (PDEs) are receiving much attention as a natural source of antioxidants. Previous research has shown that PDEs contain a series of bioactives and that their content varies depending on the fruit or vegetable source. It has also been shown that fruits and vegetables derived from organic agriculture produce more exosomes, are safer, free of toxic substances, and contain more bioactives. The aim of this study was to investigate the ability of orally administered mixes of PDE (Exocomplex^®) to restore the physiological conditions of mice treated for two weeks with hydrogen peroxide (H₂O₂), compared with mice left untreated after the period of H₂O₂ administration and mice that received only water during the experimental period. The results showed that Exocomplex^® had a high antioxidant capacity and contained a series of bioactives, including Catalase, Glutathione (GSH), Superoxide Dismutase (SOD), Ascorbic Acid, Melatonin, Phenolic compounds, and ATP. The oral administration of Exocomplex^® to the H₂O₂-treated mice re-established redox balance with reduced serum levels of both reactive oxygen species (ROS) and malondialdehyde (MDA), but also a general recovery of the homeostatic condition at the organ level, supporting the future use of PDE for health care.

Plant-derived extracellular vesicles (PDEVs) in nanomedicine for human disease and therapeutic modalities

BACKGROUND

The past few years have witnessed a significant increase in research related to plant-derived extracellular vesicles (PDEVs) in biological and medical applications. Using biochemical technologies, multiple independent groups have demonstrated the important roles of PDEVs as potential mediators involved in cell-cell communication and the exchange of bio-information between species. Recently, several contents have been well identified in PDEVs, including nucleic acids, proteins, lipids, and other active substances. These cargoes carried by PDEVs could be transferred into recipient cells and remarkably influence their biological behaviors associated with human diseases, such as cancers and inflammatory diseases. This review summarizes the latest updates regarding PDEVs and focuses on its important role in nanomedicine applications, as well as the potential of PDEVs as drug delivery strategies to develop diagnostic and therapeutic agents for the clinical management of diseases, especially like cancers.

CONCLUSION

Considering its unique advantages, especially high stability, intrinsic bioactivity and easy absorption, further elaboration on molecular mechanisms and biological factors driving the function of PDEVs will provide new horizons for the treatment of human disease.

Purposing plant-derived exosomes-like nanovesicles for drug delivery: patents and literature review

INTRODUCTION

How can biotechnology and organic agriculture be fused and promoted simultaneously to overcome the main challenges in drug delivery systems, improving the quality of the care provided, [1] patient outcomes, and [2] reducing the side effects of most of the current treatments? Unfortunately, the role of organic agriculture in future human health treatment still represents a binary organic-conventional question, a debate perpetuating an either/or mentality. However, extracellular exosomes-like nanoparticles define a new organic path that plants and vegetables can release. In this review, we concisely propose plant-derived exosome-like nanovesicles and discuss their most important biological and pharmacological roles, representing a new tool for drug delivery.

AREAS COVERED

plant-derived exosomes-like nanovesicles; nature farming; green manufacturing practice; drug delivery; organic agriculture.

EXPERT OPINION

There is growing interest in the potential use of plant-derived exosomes-like nanovesicles for various diagnostic and therapeutic applications that should translate into a supplement to current nano-pharmaceuticals. Despite their clinical potential, the lack of sensitive preparatory and analytical technologies for plant-derived exosomes-like nanovesicles poses a barrier to clinical translation. An increasing number of articles are recently published on new analytical platforms to address these challenges in cross-comparison with conventional assay methods. This review also mentions two patents from ExoLab-Italia on plant-derived exosome-like nanovesicles, respectively, on plant-derived exosome-like nanovesicles' ability to naturally deliver a series of potentially therapeutic molecules and a novel approach to upload them with therapeutic molecules.

Fisetin-loaded grape-derived nanoparticles improve anticancer efficacy in MOLT-4 cells

PURPOSE

Fisetin (FIS) is a natural flavonoid with anti-proliferative and anti-apoptotic effects on different human cancer cell lines and can be considered a therapeutic agent for ALL treatment. However, FIS has little aqueous solubility and bioavailability, limiting its therapeutic applications. Thus, novel drug delivery systems are needed to improve solubility and bioavailability of FIS. Plant-derived nanoparticles (PDNPs) could be considered a great delivery system for FIS to the target tissues. In this study, we investigated the anti-proliferative and anti-apoptotic effect of free FIS and FIS-loaded Grape-derived Nanoparticles (GDN) FIS-GDN in MOLT-4 cells.

MATERIALS/METHODS

In this study, MOLT-4 cells were treated with increasing concentration of FIS and FIS-GDN and viability of cells were assessed by MTT assay. Additionally, cellular apoptosis rate and related genes expression were evaluated using flow cytometry and Real Time-PCR methods, respectively.

RESULTS

FIS and FIS-GDN decreased cells viability and increased cells apoptosis dose-dependently, but not time dependently. Treatment of MOLT-4 cells with increasing concentrations of FIS and FIS-GDN considerably increased the expression of caspase 3, 8 and 9 and Bax level, and also decreased the expression of Bcl-2. Results indicated an increased apoptosis after increased concentration of FIS and FIS-GDN at 24, 48 and 72 h.

CONCLUSIONS

Our data proposed that FIS and FIS-GDN can induce apoptosis and have antitumor properties in MOLT-4 cells. Furthermore, compared to FIS, FIS-GDN induced more apoptosis in these cells by increasing the solubility and efficiency of FIS. Additionally, GDNs increased FIS effectiveness in proliferation inhibition and apoptosis induction.

Secretory membrane traffic in plant-microbe interactions

Plant defense responses include the extracellular release of defense-related molecules, such as pathogenesis-related proteins and secondary metabolites, as well as cell wall materials. This primarily depends on the trafficking of secretory vesicles to the plasma membrane, where they discharge their contents into the apoplastic space via soluble N-ethylmaleimide sensitive factor attachment protein receptor-assisted exocytosis. However, some pathogenic and symbiotic microbes have developed strategies to manipulate host plant exocytic pathways. Here, we discuss the mechanisms by which plant exocytic pathways function in immunity and how microbes have evolved to manipulate those pathways.

Assessment of Small Cellular Particles from Four Different Natural Sources and Liposomes by Interferometric Light Microscopy

Small particles in natural sources are a subject of interest for their potential role in intercellular, inter-organism, and inter-species interactions, but their harvesting and assessment present a challenge due to their small size and transient identity. We applied a recently developed interferometric light microscopy (ILM) to assess the number density and hydrodynamic radius (R_h) of isolated small cellular particles (SCPs) from blood preparations (plasma and washed erythrocytes) (B), spruce needle homogenate (S), suspension of flagellae of microalgae Tetraselmis chuii (T), conditioned culture media of microalgae Phaeodactylum tricornutum (P), and liposomes (L). The aliquots were also assessed by flow cytometry (FCM), dynamic light scattering (DLS), ultraviolet-visible spectrometry (UV-vis), and imaging by cryogenic transmission electron microscopy (cryo-TEM). In R_h, ILM showed agreement with DLS within the measurement error in 10 out of 13 samples and was the only method used here that yielded particle density. Cryo-TEM revealed that representative SCPs from Tetraselmis chuii flagella (T) did not have a globular shape, so the interpretation by R_h of the batch methods was biased. Cryo-TEM showed the presence of thin filaments in isolates from Phaeodactylum tricornutum conditioned culture media (P), which provides an explanation for the considerably larger R_h obtained by batch methods than the sizes of particles observed by cryo-TEM images. ILM proved convenient for assessment of number density and R_h of SCPs in blood preparations (e.g., plasma); therefore, its use in population and clinical studies is indicated.

Edible plant extracellular vesicles: An emerging tool for bioactives delivery

The extracellular vesicles (EVs) in edible food have a typical saucer-like structure and are nanoparticles released by numerous cells. They have different components and interact with other biological samples in diverse ways. Therefore, these nanoparticles could be used to develop bioactives delivery nanoplatforms and anti-inflammatory treatments to meet the stringent demands of current clinical challenges. This review aims to summarize current researches into EVs from edible plants, particularly those that can protect siRNAs or facilitate drug transportation. We will discuss their isolation, characterization and functions, their regulatory effects under various physiological and pathological conditions, and their immune regulation, anti-tumor, regeneration, and anti-inflammatory effects. We also review advances in their potential application as bioactives carriers, and medicinal and edible plants that change their EVs compositions during disease to achieve a therapy propose. It is expected that future research on plant-derived EVs will considerably expand their application.

Plant-derived extracellular vesicles: Recent advancements and current challenges on their use for biomedical applications

Extracellular vesicles (EVs) represent a diverse class of lipid bilayer membrane vesicles released by both animal and plant cells. These ubiquitous vesicles are involved in intercellular communication and transport of various biological cargos, including proteins, lipids, and nucleic acids. In recent years, interest in plant-derived EVs has increased tremendously, as they serve as a scalable and sustainable alternative to EVs derived from mammalian sources. In vitro and in vivo findings have demonstrated that these plant-derived vesicles (PDVs) possess intrinsic therapeutic activities that can potentially treat diseases and improve human health. In addition, PDVs can also act as efficient and biocompatible drug carriers. While preclinical studies have shown promising results, there are still several challenges and knowledge gaps that have to be addressed for the successful translation of PDVs into clinical applications, especially in view of the lack of standardised protocols for material handling and PDV isolation from various plant sources. This review provides the readers with a quick overview of the current understanding and research on PDVs, critically analysing the current challenges and highlighting the immense potential of PDVs as a novel class of therapeutics to treat human diseases. It is expected that this work will guide scientists to address the knowledge gaps currently associated with PDVs and promote new advances in plant-based therapeutic solutions.

Species-Specific Plant-Derived Nanoparticle Characteristics

Medicinal and agricultural plants contain numerous phytochemical compounds with pronounced biological effects on human health. They are known to encapsulate most of their characteristic bioactive compounds within membranous elements of intercellular communication known as exosomes. These nanovesicles serve as capsules protecting their biological activity and improving their penetration into the tissue. Therefore, the application of plant exosome preparations holds considerable potential for cosmetics and pharmacy, but the quality and consistency of plant material for exosome isolation is of critical importance. Therefore, in this study, we aimed to evaluate yield, size distribution patterns, and antioxidant properties between nanovesicle preparations of the following portfolio of medicinal plants: Kalanchoe daigremontiana, Artemisia absinthium, Hypericum perforatum, Silybum marianum, Chelidonium majus, and Scutellaria baicalensis. Results showed that nanoparticle yield, size distribution, and antioxidant activities were specific to plant species. Compared to other plants, nanoparticle preparations from Artemisia absinthium were distinguished by remarkably higher yield and concentration, while the highest antioxidant activity of plant-derived nanoparticle preparations per weight and per particle was determined to occur in Chelidonium majus and Hypericum perforatum samples. Results showed no significant correlation in DPPH (2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and FRAP (ferric reducing antioxidant power) between plant material and nanoparticle preparations. More detailed biochemical analysis of exosome preparations is necessary to validate their biological activity and its relation to source plant cells.

Exosomes as Novel Delivery Systems for Application in Traditional Chinese Medicine

Exosomes, as gifts of nature derived from various cell types with a size range from ~40 to 160 nm in diameter, have gained attention recently. They are composed of a lipid membrane bilayer structure containing different constituents, such as surface ligands and receptors, from the parental cells. Originating from a variety of sources, exosomes have the ability to participate in a diverse range of biological processes, including the regulation of cellular communication. On account of their ideal native structure and characteristics, exosomes are taken into account as drug delivery systems (DDSs). They can provide profound effects on conveying therapeutic agents with great advantages, including specific targeting, high biocompatibility, and non-toxicity. Further, they can also be considered to ameliorate natural compounds, the main constituents of traditional Chinese medicine (TCM), which are usually ignored due to the complexity of their structures, poor stability, and unclear mechanisms of action. This review summarizes the classification of exosomes as well as the research progress on exosome-based DDSs for the treatment of different diseases in TCM. Furthermore, this review discusses the advantages and challenges faced by exosomes to contribute to their further investigation and application.

Plant-derived nanovesicles: Current understanding and applications for cancer therapy

Plant-derived vesicles (PDVs) are membranous structures that originate from plant cells and are responsible for multiple physiological and pathological functions. In the last decade, PDVs have gained much attention for their involvement in different biological processes, including intercellular communication and defense response, and recent scientific evidence has opened a new avenue for their applications in cancer treatment. Nevertheless, much remains unknown about these vesicles, and current research remains inconsistent. This review aims to provide a comprehensive introduction to PDVs, from their biological characteristics to purification methods, and to summarize the status of their potential development for cancer therapy.

Plant hairy roots for the production of extracellular vesicles with antitumor bioactivity

Plant extracellular vesicles (EVs) concentrate and deliver different types of bioactive molecules in human cells and are excellent candidates for a next-generation drug delivery system. However, the lack of standard protocols for plant EV production and the natural variations of their biomolecular cargo pose serious limitation to their use as therapeutics. To overcome these issues, we set up a versatile and standardized procedure to purify plant EVs from hairy root (HR) cultures, a versatile biotechnological system, already successfully employed as source of bioactive molecules with pharmaceutical and nutraceutical relevance. Herewith, we report that HR of Salvia dominica represent an excellent platform for the production of plant EVs. In particular, EVs derived from S. dominica HRs are small round-shaped vesicles carrying typical EV-associated proteins such as cytoskeletal components, chaperon proteins and integral membrane proteins including the tetraspanin TET-7. Interestingly, the HR-derived EVs showed selective and strong pro-apoptotic activity in pancreatic and mammary cancer cells. These results reveal that plant hairy roots may be considered a new promising tool in plant biotechnology for the production of extracellular vesicles for human health.

Emergence of Edible Plant-Derived Nanovesicles as Functional Food Components and Nanocarriers for Therapeutics Delivery: Potentials in Human Health and Disease

Extracellular vesicles (EVs) are a highly heterogeneous population of membranous particles that are secreted by almost all types of cells across different domains of life, including plants. In recent years, studies on plant-derived nanovesicles (PDNVs) showed that they could modulate metabolic reactions of the recipient cells, affecting (patho)physiology with health benefits in a trans-kingdom manner. In addition to its bioactivity, PDNV has advantages over conventional nanocarriers, making its application promising for therapeutics delivery. Here, we discuss the characteristics of PDNV and highlight up-to-date pre-clinical and clinical evidence, focusing on therapeutic application.

Theragnostic Applications of Mammal and Plant-Derived Extracellular Vesicles: Latest Findings, Current Technologies, and Prospects

The way cells communicate is not fully understood. However, it is well-known that extracellular vesicles (EVs) are involved. Researchers initially thought that EVs were used by cells to remove cellular waste. It is now clear that EVs function as signaling molecules released by cells to communicate with one another, carrying a cargo representing the mother cell. Furthermore, these EVs can be found in all biological fluids, making them the perfect non-invasive diagnostic tool, as their cargo causes functional changes in the cells upon receiving, unlike synthetic drug carriers. EVs last longer in circulation and instigate minor immune responses, making them the perfect drug carrier. This review sheds light on the latest development in EVs isolation, characterization and, application as therapeutic cargo, novel drug loading techniques, and diagnostic tools. We also address the advancement in plant-derived EVs, their characteristics, and applications; since plant-derived EVs only recently gained focus, we listed the latest findings. Although there is much more to learn about, EV is a wide field of research; what scientists have discovered so far is fascinating. This paper is suitable for those new to the field seeking to understand EVs and those already familiar with it but wanting to review the latest findings.

Unconventional Secretion of Plant Extracellular Vesicles and Their Benefits to Human Health: A Mini Review

Mechanisms devoted to the secretion of proteins via extracellular vesicles (EVs) have been found in mammals, yeasts, and plants. Since they transport a number of leader-less proteins to the plasma membrane or the extracellular space, EVs are considered part of Unconventional protein secretion (UPS) routes. UPS involving EVs are a relatively new field in plants. Aside from their role in plant physiology and immunity, plant extracts containing EVs have also been shown to be beneficial for human health. Therefore, exploring the use of plant EVs in biomedicine and their potential as drug delivery tools is an exciting avenue. Here we give a summary of the state of knowledge on plant EVs, their crosstalk with mammalian systems and potential research routes that could lead to practical applications in therapeutic drug delivery.

Plant-Derived Exosomes as A Drug-Delivery Approach for the Treatment of Inflammatory Bowel Disease and Colitis-Associated Cancer

Inflammatory bowel disease (IBD) is a chronic recurrent intestinal disease and includes Crohn’s disease (CD) and ulcerative colitis (UC). Due to the complex etiology of colitis, the current treatments of IBD are quite limited and are mainly concentrated on the remission of the disease. In addition, the side effects of conventional drugs on the body cannot be ignored. IBD also has a certain relationship with colitis-associated cancer (CAC), and inflammatory cells can produce a large number of tumor-promoting cytokines to promote tumor progression. In recent years, exosomes from plants have been found to have the ability to load drugs to target the intestine and have great potential for the treatment of intestinal diseases. This plant-derived exosome-targeting delivery system can load chemical or nucleic acid drugs and deliver them to intestinal inflammatory sites stably and efficiently. This review summarizes the pathophysiological characteristics of IBD and CAC as well as the application and prospect of plant exosomes in the treatment of IBD and CAC.

Plant-RNA in Extracellular Vesicles: The Secret of Cross-Kingdom Communication

The release of extracellular vesicles (EVs) is a common language, used by living organisms from different kingdoms as a means of communication between them. Extracellular vesicles are lipoproteic particles that contain many biomolecules, such as proteins, nucleic acids, and lipids. The primary role of EVs is to convey information to the recipient cells, affecting their function. Plant-derived extracellular vesicles (PDEVs) can be isolated from several plant species, and the study of their biological properties is becoming an essential starting point to study cross-kingdom communication, especially between plants and mammalians. Furthermore, the presence of microRNAs (miRNAs) in PDEVs represents an interesting aspect for understanding how PDEVs can target the mammalian genes involved in pathological conditions such as cancer, inflammation, and oxidative stress. In particular, this review focuses on the history of PDEVs, from their discovery, to purification from various matrices, and on the functional role of PDEV-RNAs in cross-kingdom interactions. It is worth noting that miRNAs packaged in PDEVs can be key modulators of human gene expression, representing potential therapeutic agents.

Natural exosome-like nanovesicles from edible tea flowers suppress metastatic breast cancer via ROS generation and microbiota modulation

Although several artificial nanotherapeutics have been approved for practical treatment of metastatic breast cancer, their inefficient therapeutic outcomes, serious adverse effects, and high cost of mass production remain crucial challenges. Herein, we developed an alternative strategy to specifically trigger apoptosis of breast tumors and inhibit their lung metastasis by using natural nanovehicles from tea flowers (TFENs). These nanovehicles had desirable particle sizes (131 nm), exosome-like morphology, and negative zeta potentials. Furthermore, TFENs were found to contain large amounts of polyphenols, flavonoids, functional proteins, and lipids. Cell experiments revealed that TFENs showed strong cytotoxicities against cancer cells due to the stimulation of reactive oxygen species (ROS) amplification. The increased intracellular ROS amounts could not only trigger mitochondrial damage, but also arrest cell cycle, resulting in the in vitro anti-proliferation, anti-migration, and anti-invasion activities against breast cancer cells. Further mice investigations demonstrated that TFENs after intravenous (i.v.) injection or oral administration could accumulate in breast tumors and lung metastatic sites, inhibit the growth and metastasis of breast cancer, and modulate gut microbiota. This study brings new insights to the green production of natural exosome-like nanoplatform for the inhibition of breast cancer and its lung metastasis via i.v. and oral routes.

Effective methods for isolation and purification of extracellular vesicles from plants

Plant extracellular vesicles (EVs) play critical roles in the cross-kingdom trafficking of molecules from hosts to interacting microbes, most notably in plant defense responses. However, the isolation of pure, intact EVs from plants remains challenging. A variety of methods have been utilized to isolate plant EVs from apoplastic washing fluid (AWF). Here, we compare published plant EV isolation methods, and provide our recommended method for the isolation and purification of plant EVs. This method includes a detailed protocol for clean AWF collection from Arabidopsis thaliana leaves, followed by EV isolation via differential centrifugation. To further separate and purify specific subclasses of EVs from heterogeneous vesicle populations, density gradient ultracentrifugation and immunoaffinity capture are then utilized. We found that immunoaffinity capture is the most precise method for specific EV subclass isolation when suitable specific EV biomarkers and their corresponding antibodies are available. Overall, this study provides a guide for the selection and optimization of EV isolation methods for desired downstream applications.

Enhanced therapeutic efficacy of a novel self-micellizing nanoformulation-loading fisetin against acetaminophen-induced liver injury

Aim: To evaluate the feasibility of using dipotassium glycyrrhizinate (DG) as a nanocarrier-loading fisetin (FIT) with strengthened treatment efficacies against liver injury induced by acetaminophen overdose. Methods: DG-FIT was prepared, and its efficacy against liver injury induced by acetaminophen overdose was evaluated. Results: DG-FIT was successfully fabricated with excellent physicochemical properties. DG-FIT could be easily dissolved in water to form a clear micelle solution with high FIT encapsulation efficiency. FIT in DG-FIT exhibited a dramatically improved aqueous solubility. DG-FIT improved intestinal permeation. Regarding in vivo efficacies, DG-FIT exhibited significant effect against acetaminophen overdose by suppressing oxidative stress and proinflammatory cytokines involved. Conclusion: DG-FIT formulation possibly represents a promising method for strengthening the efficacy of FIT against acetaminophen-induced liver injury.

Extracellular Vesicles: Emerging Players in Plant Defense Against Pathogens

Communication between plants and interacting microorganisms requires functional molecule trafficking, which is essential for host defense and pathogen virulence. Extracellular vesicles (EVs) are single membrane-bound spheres that carry complex cargos, including lipids, proteins, and nucleic acids. They mediate cell-to-cell communication via the transfer of molecules between cells. Plant EVs have been isolated from many plant species and play a prominent role in immune system modulation and plant defense response. Recent studies have shown that plant EVs are emerging players in cross-kingdom regulation and contribute to plant immunity by mediating the trafficking of regulatory small RNA into pathogens, leading to the silencing of pathogen virulence-related genes. This review summarizes the current understanding of plant EV isolation technologies, the role of plant EVs in plant immunity, and the mechanism of plant EV biogenesis, as well as approaches for how these findings can be developed into innovative strategies for crop protection.

Plant Extracellular Vesicles and Nanovesicles: Focus on Secondary Metabolites, Proteins and Lipids with Perspectives on Their Potential and Sources

While human extracellular vesicles (EVs) have attracted a big deal of interest and have been extensively characterized over the last years, plant-derived EVs and nanovesicles have earned less attention and have remained poorly investigated. Although a series of investigations already revealed promising beneficial health effects and drug delivery properties, adequate (pre)clinical studies are rare. This fact might be caused by a lack of sources with appropriate qualities. Our study introduces plant cell suspension culture as a new and well controllable source for plant EVs. Plant cells, cultured in vitro, release EVs into the growth medium which could be harvested for pharmaceutical applications. In this investigation we characterized EVs and nanovesicles from distinct sources. Our findings regarding secondary metabolites indicate that these might not be packaged into EVs in an active manner but enriched in the membrane when lipophilic enough, since apparently lipophilic compounds were associated with nanovesicles while more hydrophilic structures were not consistently found. In addition, protein identification revealed a possible explanation for the mechanism of EV cell wall passage in plants, since cell wall hydrolases like 1,3-β-glucosidases, pectinesterases, polygalacturonases, β-galactosidases and β-xylosidase/α-L-arabinofuranosidase 2-like are present in plant EVs and nanovesicles which might facilitate cell wall transition. Further on, the identified proteins indicate that plant cells secrete EVs using similar mechanisms as animal cells to release exosomes and microvesicles.