Message in a Bubble: Shuttling Small RNAs and Proteins Between Cells and Interacting Organisms Using Extracellular Vesicles

Yin-Yang: two sides of extracellular vesicles in inflammatory diseases

The concept of Yin-Yang, originating in ancient Chinese philosophy, symbolizes two opposing but complementary forces or principles found in all aspects of life. This concept can be quite fitting in the context of extracellular vehicles (EVs) and inflammatory diseases. Over the past decades, numerous studies have revealed that EVs can exhibit dual sides, acting as both pro- and anti-inflammatory agents, akin to the concept of Yin-Yang theory (i.e., two sides of a coin). This has enabled EVs to serve as potential indicators of pathogenesis or be manipulated for therapeutic purposes by influencing immune and inflammatory pathways. This review delves into the recent advances in understanding the Yin-Yang sides of EVs and their regulation in specific inflammatory diseases. We shed light on the current prospects of engineering EVs for treating inflammatory conditions. The Yin-Yang principle of EVs bestows upon them great potential as, therapeutic, and preventive agents for inflammatory diseases.

Chimeric antigen receptor (CAR) T-cell therapy: Harnessing extracellular vesicles for enhanced efficacy

A cutting-edge approach in cell-based immunotherapy for combating resistant cancer involves genetically engineered chimeric antigen receptor T (CAR-T) lymphocytes. In recent years, these therapies have demonstrated effectiveness, leading to their commercialization and clinical application against certain types of cancer. However, CAR-T therapy faces limitations, such as the immunosuppressive tumour microenvironment (TME) that can render CAR-T cells ineffective, and the adverse side effects of the therapy, including cytokine release syndrome (CRS). Extracellular vesicles (EVs) are a diverse group of membrane-bound particles released into the extracellular environment by virtually all cell types. They are essential for intercellular communication, transferring cargoes such as proteins, lipids, various types of RNAs, and DNA fragments to target cells, traversing biological barriers both locally and systemically. EVs play roles in numerous physiological processes, with those from both immune and non-immune cells capable of modulating the immune system through activation or suppression. Leveraging this capability of EVs to enhance CAR-T cell therapy could represent a significant advancement in overcoming its current limitations. This review examines the current landscape of CAR-T cell immunotherapy and explores the potential role of EVs in augmenting its therapeutic efficacy.

Multidimensional analysis of tumor stem cells: from biological properties, metabolic adaptations to immune escape mechanisms

As a key factor in tumorigenesis, progression, recurrence and metastasis, the biological properties, metabolic adaptations and immune escape mechanisms of CSCs are the focus of current oncological research. CSCs possess self-renewal, multidirectional differentiation and tumorigenicity, and their mechanisms of action can be elucidated by the clonal evolution, hierarchical model and the dynamic CSCs model, of which the dynamic model is widely recognized due to its better explanation of the function and origin of CSCs. The origin hypothesis of CSCs involves cell-cell fusion, horizontal gene transfer, genomic instability and microenvironmental regulation, which together shape the diversity of CSCs. In terms of classification, CSCs include primary CSCs (pri-CSCs), precancerous stem cells (pre-CSCs), migratory CSCs (mig-CSCs), and chemo-radiotherapy-resistant CSCs (cr-CSCs and rr-CSCs), with each type playing a specific role in tumor progression. Surface markers of CSCs, such as CD24, CD34, CD44, CD90, CD133, CD166, EpCAM, and LGR5, offer the possibility of identifying, isolating, and targeting CSCs, but the instability and heterogeneity of their expression increase the difficulty of treatment. CSCs have adapted to their survival needs through metabolic reprogramming, showing the ability to flexibly switch between glycolysis and oxidative phosphorylation (OXPHOS), as well as adjustments to amino acid and lipid metabolism. The Warburg effect typifies their metabolic profiles, and altered glutamine and fatty acid metabolism further contributes to the rapid proliferation and survival of CSCs. CSCs are able to maintain their stemness by regulating the metabolic networks to maintain their stemness characteristics, enhance antioxidant defences, and adapt to therapeutic stress. Immune escape is another strategy for CSCs to maintain their survival, and CSCs can effectively evade immune surveillance through mechanisms such as up-regulating PD-L1 expression and promoting the formation of an immunosuppressive microenvironment. Together, these properties reveal the multidimensional complexity of CSCs, underscoring the importance of a deeper understanding of the biology of CSCs for the development of more effective tumor therapeutic strategies. In the future, therapies targeting CSCs will focus on precise identification of surface markers, intervention of metabolic pathways, and overcoming immune escape, with the aim of improving the relevance and efficacy of cancer treatments, and ultimately improving patient prognosis.

Domestication and Genetic Improvement Alter the Symbiotic Microbiome Structure and Function of Tomato Leaf and Fruit Pericarp

Many studies have attempted to explore the changes in the structure and function of symbiotic microbiomes, as well as the underlying genetic mechanism during crop domestication. However, most of these studies have focused on crop root microbiomes, while those on leaf and fruit are rare. In this study, we generated a comprehensive dataset including the metagenomic (leaf) and metatranscriptomic (fruit pericarp in the orange stage) data of hundreds of germplasms from three tomato clades: Solanum pimpinellifolium (PIM), cherry tomato (S. lycopersicum var. cerasiforme) (CER), and S. lycopersicum group (BIG). We investigated the effect of domestication and improvement processes on the structure of the symbiotic microbiome of tomato leaf and fruit pericarp, as well as its genetic basis. We were able to obtain the composition of the symbiotic microbiome of tomato leaf and fruit pericarp, based on which the tomato clade (PIM, CER, or BIG) was predicted with high accuracy through machine learning methods. In the processes of tomato domestication and improvement, changes were observed in the relative abundance of specific bacterial taxa, Bacillus for example, in the tomato leaf and fruit pericarp symbiotic microbiomes, as well as in the function of these symbiotic microbiomes. In addition, SNP loci that were significantly associated with microbial species that are characteristic of tomato leaf were identified. Our results show that domestication and genetic improvement processes alter the symbiotic microbiome structure and function of tomato leaf and fruit pericarp. We propose that leaf and fruit microbiomes are more suitable for revealing changes in symbiotic microbiomes during the domestication process and the underlying genetic basis for these changes due to the exclusion of the influence of environmental factors such as soil types on the microbiome structure.

circVAPA-rich small extracellular vesicles derived from gastric cancer promote neural invasion by inhibiting SLIT2 expression in neuronal cells

Gastric cancer (GC) is one of the most common cancer worldwide. Neural invasion (NI) is considered as the symbiotic interaction between nerves and cancers, which strongly affects the prognosis of GC patients. Small extracellular vesicles (sEVs) play a key role in intercellular communication. However, whether sEVs mediate GC-NI remains unexplored. In this study, sEVs release inhibitor reduces the NI potential of GC cells. Muscarinic receptor M3 on GC-derived sEVs regulates their absorption by neuronal cells. The enrichment of sEV-circVAPA in NI-positive patients' serum is validated by serum high throughput sEV-circRNA sequencing and clinical samples. sEV-circVAPA promotes GC-NI in vitro and in vivo. Mechanistically, sEV-circVAPA decreases SLIT2 transcription by miR-548p/TGIF2 and inhibits SLIT2 translation via binding to eIF4G1, thereby downregulates SLIT2 expression in neuronal cells and finally induces GC-NI. Together, this work identifies the preferential absorption mechanism of GC-derived sEVs by neuronal cells and demonstrates a previously undefined role of GC-derived sEV-circRNA in GC-NI, which provides new insight into sEV-circRNA based diagnostic and therapeutic strategies for NI-positive GC patients.

New Origins of Yeast, Plant and Bacterial-Derived Extracellular Vesicles to Expand and Advance Compound Delivery

Extracellular vesicles (EVs) constitute a sophisticated molecular exchange mechanism highly regarded for their potential as a next-generation platform for compound delivery. However, identifying sustainable and biologically safe sources of EVs remains a challenge. This work explores the emergence of novel sources of plant and bacterial-based EVs, such as those obtained from food industry by-products, known as BP-EVs, and their potential to be used as safer and biocompatible nanocarriers, addressing some of the current challenges of the field. These novel sources exhibit remarkable oral bioavailability and biodistribution, with minimal cytotoxicity and a selective targeting capacity toward the central nervous system, liver, and skeletal tissues. Additionally, we review the ease of editing these recently uncovered nanocarrier-oriented vesicles using common EV editing methods, examining the cargo-loading processes applicable to these sources, which involve both passive and active functionalization methods. While the primary focus of these novel sources of endogenous EVs is on molecule delivery to the central nervous system and skeletal tissue based on their systemic target preference, their use, as reviewed here, extends beyond these key applications within the biotechnological and biomedical fields.

Identification of mungbean yellow mosaic India virus and susceptibility-related metabolites in the apoplast of mung bean leaves

KEY MESSAGE

The investigation of MYMIV-infected mung bean leaf apoplast revealed viral genome presence, increased EVs secretion, and altered stress-related metabolite composition, providing comprehensive insights into plant-virus interactions. The apoplast, an extracellular space around plant cells, plays a vital role in plant-microbe interactions, influencing signaling, defense, and nutrient transport. While the involvement of apoplast and extracellular vesicles (EVs) in RNA virus infection is documented, the role of the apoplast in plant DNA viruses remains unclear. This study explores the apoplast's role in mungbean yellow mosaic India virus (MYMIV) infection. Our findings demonstrate the presence of MYMIV genomic components in apoplastic fluid, suggesting potential begomovirus cell-to-cell movement via the apoplast. Moreover, MYMIV infection induces increased EVs secretion into the apoplast. NMR-based metabolomics reveals altered metabolic profiles in both apoplast and symplast in response to MYMIV infection, highlighting key metabolites associated with stress and defense mechanisms. The data show an elevation of α- and β-glucose in both apoplast and symplast, suggesting a shift in glucose utilization. Interestingly, this increase in glucose does not contribute to the synthesis of phenolic compounds, potentially influencing the susceptibility of mung bean to MYMIV. Fructose levels increase in the symplast, while apoplastic sucrose levels rise significantly. Symplastic aspartate levels increase, while proline exhibits elevated concentration in the apoplast and reduced concentration in the cytosol, suggesting a role in triggering a hypersensitive response. These findings underscore the critical role of the apoplast in begomovirus infection, providing insights for targeted viral disease management strategies.

Trans-Species Mobility of RNA Interference between Plants and Associated Organisms

Trans-species RNA interference (RNAi) occurs naturally when small RNAs (sRNAs) silence genes in species different from their origin. This phenomenon has been observed between plants and various organisms including fungi, animals and other plant species. Understanding the mechanisms used in natural cases of trans-species RNAi, such as sRNA processing and movement, will enable more effective development of crop protection methods using host-induced gene silencing (HIGS). Recent progress has been made in understanding the mechanisms of cell-to-cell and long-distance movement of sRNAs within individual plants. This increased understanding of endogenous plant sRNA movement may be translatable to trans-species sRNA movement. Here, we review diverse cases of natural trans-species RNAi focusing on current theories regarding intercellular and long-distance sRNA movement. We also touch on trans-species sRNA evolution, highlighting its research potential and its role in improving the efficacy of HIGS.

Participation of miR165a in the Phytochrome Signal Transduction in Maize (Zea mays L.) Leaves under Changing Light Conditions

The involvement of the microRNA miR165a in the light-dependent mechanisms of regulation of target genes in maize (Zea mays) has been studied. The light-induced change in the content of free miR165a was associated with its binding by the AGO10 protein and not with a change in the rate of its synthesis from the precursor. The use of knockout Arabidopsis plants for the phytochrome A and B genes demonstrated that the presence of an active form of phytochrome B causes an increase in the level of the RNA-induced silencing miR165a complex, which triggers the degradation of target mRNAs. The two fractions of vesicles from maize leaves, P40 and P100 that bind miR165a, were isolated by ultracentrifugation. The P40 fraction consisted of larger vesicles of the size >0.170 µm, while the P100 fraction vesicles were <0.147 µm. Based on the quantitative PCR data, the predominant location of miR165a on the surface of extracellular vesicles of both fractions was established. The formation of the active form of phytochrome upon the irradiation of maize plants with red light led to a redistribution of miR165a, resulting in an increase in its proportion inside P40 vesicles and a decrease in P100 vesicles.

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.

Molecular mechanisms and therapeutic application of extracellular vesicles from plants

Small extracellular vesicles (sEVs) isolated from animal sources are among the most investigated types of cell-free therapeutic tools to cure different diseases. sEVs have been isolated from a variety of sources, ranging from prokaryotes to animals and plants. Human-derived sEVs have many uses in pre- and clinical studies in medicine and drug delivery, while plant-derived EVs, also known as plant-derived nanovesicles (PDNVs), have not been widely investigated until the second decade of the 21st century. For the past five years, there has been a rapid rise in the use of plant EVs as a therapeutic tool due to the ease of massive production with high efficacy and yield of preparation. Plant EVs contain various active biomolecules such as proteins, regulatory RNAs, and secondary metabolites and play a key role in inter-kingdom communications. Many studies have already investigated the potential application of plant EVs in preventing and treating cancer, inflammation, infectious diseases, and tissue regeneration with no sign of toxicity and are therefore considered safe. However, due to a lack of universal markers, the properties of plant EVs have not been extensively studied. Concerns regarding the safety and therapeutic function of plant EVs derived from genetically modified plants have been raised. In this paper, we review the physiological role of EVs in plants. Moreover, we focus on molecular and cellular mechanisms involved in the therapeutic effects of plant EVs on various human diseases. We also provide detailed information on the methodological aspects of plant EV isolation and analysis, which could pave the way for future clinical translation.

Development of rice bran-derived nanoparticles with excellent anti-cancer activity and their application for peritoneal dissemination

BACKGROUND

Rice bran a by-product of the rice milling process is currently underutilized. Recent studies have shown that plant-derived nanoparticles (pdNPs) can be mass-produced at a low cost and exhibit biological and therapeutic activities. Rice bran contains various anti-cancer compounds, including γ-oryzanol and γ-tocotrienol, and rice bran-derived nanoparticles (rbNPs) can be employed as novel therapeutic agents for cancer treatment.

RESULTS

Koshihikari rice bran was suspended in water, and the suspension was centrifuged and filtered through a 0.45-µm-pore size syringe filter. The filtrate was ultracentrifuged, and the precipitates were suspended to obtain rbNPs. The rbNPs were negatively charged exosome-like nanoparticles with an average diameter of approximately 130 nm. The rbNPs exhibited cytotoxic activities against cancer cells but not against normal cells. The cytotoxic activity of rbNPs to murine colon adenocarcinoma colon26 cells was significantly greater than DOXIL® or other pdNPs. The rbNPs induced cell cycle arrest and apoptosis, and reduced the expression of proliferative proteins, including β-catenin and cyclin D1. Intraperitoneal injections of rbNPs into mice bearing peritoneal dissemination of colon26 cells significantly suppressed tumor growth with no significant adverse effects.

CONCLUSION

These results indicated that rbNPs are promising nanoparticles, hold significant potential for anti-cancer applications, and are expected to play a vital role in cancer treatment.

A Review of the Use of Extracellular Vesicles in the Treatment of Neonatal Diseases: Current State and Problems with Translation to the Clinic

Neonatal disorders, particularly those resulting from prematurity, pose a major challenge in health care and have a significant impact on infant mortality and long-term child health. The limitations of current therapeutic strategies emphasize the need for innovative treatments. New cell-free technologies utilizing extracellular vesicles (EVs) offer a compelling opportunity for neonatal therapy by harnessing the inherent regenerative capabilities of EVs. These nanoscale particles, secreted by a variety of organisms including animals, bacteria, fungi and plants, contain a repertoire of bioactive molecules with therapeutic potential. This review aims to provide a comprehensive assessment of the therapeutic effects of EVs and mechanistic insights into EVs from stem cells, biological fluids and non-animal sources, with a focus on common neonatal conditions such as hypoxic-ischemic encephalopathy, respiratory distress syndrome, bronchopulmonary dysplasia and necrotizing enterocolitis. This review summarizes evidence for the therapeutic potential of EVs, analyzes evidence of their mechanisms of action and discusses the challenges associated with the implementation of EV-based therapies in neonatal clinical practice.

Micro Trojan horses: Engineering extracellular vesicles crossing biological barriers for drug delivery

The biological barriers of the body, such as the blood-brain, placental, intestinal, skin, and air-blood, protect against invading viruses and bacteria while providing necessary physical support. However, these barriers also hinder the delivery of drugs to target tissues, reducing their therapeutic efficacy. Extracellular vesicles (EVs), nanostructures with a diameter ranging from 30 nm to 10 μm secreted by cells, offer a potential solution to this challenge. These natural vesicles can effectively pass through various biological barriers, facilitating intercellular communication. As a result, artificially engineered EVs that mimic or are superior to the natural ones have emerged as a promising drug delivery vehicle, capable of delivering drugs to almost any body part to treat various diseases. This review first provides an overview of the formation and cross-species uptake of natural EVs from different organisms, including animals, plants, and bacteria. Later, it explores the current clinical applications, perspectives, and challenges associated with using engineered EVs as a drug delivery platform. Finally, it aims to inspire further research to help bioengineered EVs effectively cross biological barriers to treat diseases.

Neuroprotective properties of exosomes and chitosan nanoparticles of Tomafran, a bioengineered tomato enriched in crocins

Saffron has many pharmacological properties in addition to being a frequently used food seasoning. Crocin and picrocrocin which accumulate in saffron stigma, are responsible for these pharmacological properties. These natural products have health-promoting effects for the prevention and treatment of numerous diseases, including age-related cognitive and memory disfunction. Currently, crocin and picrocrocin are obtained from saffron, considered as the spice with the highest price in the market. To develop an efficient and low-cost approach to producing these compounds with high bioactivity, biosynthetic genes isolated from saffron can be exploited in the metabolic engineering of heterologous hosts and the production of crocins in productive crop plants. Recently, we engineered tomato fruit producing crocins (Tomafran). In this study, we demonstrated that crocin-rich extract, encapsulated in chitosan or in exosomes may function as a neuroprotective strategy. Crocins contained in the Tomafran extracts and much lower doses in chitosan nanoparticles or exosomes were enough to rescue the neuroblastoma cell line SH-SY5Y after damage caused by okadaic acid. Our results confirm the neuroprotective effect of Tomafran and its exosomes that may be useful for the delay or prevention of neurodegenerative disorders such as Alzheimer's disease.

Plant mRNAs move into a fungal pathogen via extracellular vesicles to reduce infection

Cross-kingdom small RNA trafficking between hosts and microbes modulates gene expression in the interacting partners during infection. However, whether other RNAs are also transferred is unclear. Here, we discover that host plant Arabidopsis thaliana delivers mRNAs via extracellular vesicles (EVs) into the fungal pathogen Botrytis cinerea. A fluorescent RNA aptamer reporter Broccoli system reveals host mRNAs in EVs and recipient fungal cells. Using translating ribosome affinity purification profiling and polysome analysis, we observe that delivered host mRNAs are translated in fungal cells. Ectopic expression of two transferred host mRNAs in B. cinerea shows that their proteins are detrimental to infection. Arabidopsis knockout mutants of the genes corresponding to these transferred mRNAs are more susceptible. Thus, plants have a strategy to reduce infection by transporting mRNAs into fungal cells. mRNAs transferred from plants to pathogenic fungi are translated to compromise infection, providing knowledge that helps combat crop diseases.

Leafhopper salivary vitellogenin mediates virus transmission to plant phloem

Salivary effectors of piercing-sucking insects can suppress plant defense to promote insect feeding, but it remains largely elusive how they facilitate plant virus transmission. Leafhopper Nephotettix cincticeps transmits important rice reovirus via virus-packaging exosomes released from salivary glands and then entering the rice phloem. Here, we report that intact salivary vitellogenin of N. cincticeps (NcVg) is associated with the GTPase Rab5 of N. cincticeps (NcRab5) for release from salivary glands. In virus-infected salivary glands, NcVg is upregulated and packaged into exosomes mediated by virus-induced NcRab5, subsequently entering the rice phloem. The released NcVg inherently suppresses H2O2 burst of rice plants by interacting with rice glutathione S-transferase F12, an enzyme catalyzing glutathione-dependent oxidation, thus facilitating leafhoppers feeding. When leafhoppers transmit virus, virus-upregulated NcVg thus promotes leafhoppers feeding and enhances viral transmission. Taken together, the findings provide evidence that viruses exploit insect exosomes to deliver virus-hijacked effectors for efficient transmission.

Plant-derived nanovesicles as an emerging platform for cancer therapy

Plant-derived nanovesicles (PDNVs) derived from natural green products have emerged as an attractive nanoplatform in biomedical application. They are usually characterized by unique structural and biological functions, such as the bioactive lipids/proteins/nucleic acids as therapeutics and targeting groups, immune-modulation, and long-term circulation. With the rapid development of nanotechnology, materials, and synthetic chemistry, PDNVs can be engineered with multiple functions for efficient drug delivery and specific killing of diseased cells, which represent an innovative biomaterial with high biocompatibility for fighting against cancer. In this review, we provide an overview of the state-of-the-art studies concerning the development of PDNVs for cancer therapy. The original sources, methods for obtaining PDNVs, composition and structure are introduced systematically. With an emphasis on the featured application, the inherent anticancer properties of PDNVs as well as the strategies in constructing multifunctional PDNVs-based nanomaterials will be discussed in detail. Finally, some scientific issues and technical challenges of PDNVs as promising options in improving anticancer therapy will be discussed, which are expected to promote the further development of PDNVs in clinical translation.

Gene-editing technology, from macromolecule therapeutics to organ transplantation: Applications, limitations, and prospective uses

Gene editing technologies (GETs) could induce gene knockdown or gene knockout for biomedical applications. The clinical success of gene silence by RNAi therapies pays attention to other GETs as therapeutic approaches. This review aims to highlight GETs, categories, mechanisms, challenges, current use, and prospective applications. The different academic search engines, electronic databases, and bibliographies of selected articles were used in the preparation of this review with a focus on the fundamental considerations. The present results revealed that, among GETs, CRISPR/Cas9 has higher editing efficiency and targeting specificity compared to other GETs to insert, delete, modify, or replace the gene at a specific location in the host genome. Therefore, CRISPR/Cas9 is talented in the production of molecular, tissue, cell, and organ therapies. Consequently, GETs could be used in the discovery of innovative therapeutics for genetic diseases, pandemics, cancer, hopeless diseases, and organ failure. Specifically, GETs have been used to produce gene-modified animals to spare human organ failure. Genetically modified pigs are used in clinical trials as a source of heart, liver, kidneys, and lungs for xenotransplantation (XT) in humans. Viral, non-viral, and hybrid vectors have been utilized for the delivery of GETs with some limitations. Therefore, extracellular vesicles (EVs) are proposed as intelligent and future cargoes for GETs delivery in clinical applications. This study concluded that GETs are promising for the production of molecular, cellular, and organ therapies. The use of GETs as XT is still in the early stage as well and they have ethical and biosafety issues.

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.

Plant exosomes: nano conveyors of pathogen resistance

The entry of a pathogen into a plant host is a complex process involving multiple steps. Survival techniques from the pathogen and the defense mechanisms of the plant lead to a plethora of molecular interactions during the operation. Plant extracellular vesicles, especially the exosomes in the size range of 50-150 nm play a crucial role in plant defense. They act as signalosomes capable of transporting bioactive lipids, proteins, RNA and metabolites between the host and the pathogen. Recent research works have revealed that anti-microbial compounds, stress response proteins and small RNA are among the contents of these extracellular vesicles. The current review article analyses the cruciality of the cross-talk between the host and the pathogen organized through trafficking of small RNA via exosomes towards RNA induced gene silencing in the pathogenic organisms. Recent studies have shown that extracellular vesicles released by both plants and the pathogens, play a crucial role in cross-kingdom communication, thereby regulating the host response and contributing to plant immunity. An in-depth understanding of the mechanism by which the EVs mediate this inter-species and cross-kingdom regulation is currently needed to develop sustainable plant-protection strategies. The review highlights on the latest advances in understanding the role of EVs in establishing host-pathogen relationship, modulating plant immunity and approaches for how these findings can be developed into innovative strategies for crop protection.

Acetylcholine (ACh) enhances Cd tolerance through transporting ACh in vesicles and modifying Cd absorption in duckweed (Lemna turionifera 5511)

Acetylcholine (ACh), an important neurotransmitter, plays a role in resistance to abiotic stress. However, the role of ACh during cadmium (Cd) resistance in duckweed (Lemna turionifera 5511) remains uncharacterized. In this study, the changes of endogenous ACh in duckweed under Cd stress has been investigated. Also, how exogenous ACh affects duckweed's ability to withstand Cd stress was studied. The ACh sensor transgenic duckweed (ACh 3.0) showed the ACh signal response under Cd stress. And ACh was wrapped and released in vesicles. Cd stress promoted ACh content in duckweed. The gene expression analysis showed an improved fatty acid metabolism and choline transport. Moreover, exogenous ACh addition enhanced Cd tolerance and decreased Cd accumulation in duckweed. ACh supplement reduced the root abscission rate, alleviated leaf etiolation, and improved chlorophyll fluorescence parameters under Cd stress. A modified calcium (Ca2+) flux and improved Cd2+ absorption were present in conjunction with it. Thus, we speculate that ACh could improve Cd resistance by promoting the uptake and accumulation of Cd, as well as the response of the Ca2+ signaling pathway. Also, plant-derived extracellular vesicles (PDEVs) were extracted during Cd stress. Therefore, these results provide new insights into the response of ACh during Cd stress.

Extracellular RNAs released by plant-associated fungi: from fundamental mechanisms to biotechnological applications

Extracellular RNAs are an emerging research topic in fungal-plant interactions. Fungal plant pathogens and symbionts release small RNAs that enter host cells to manipulate plant physiology and immunity. This communication via extracellular RNAs between fungi and plants is bidirectional. On the one hand, plants release RNAs encapsulated inside extracellular vesicles as a defense response as well as for intercellular and inter-organismal communication. On the other hand, recent reports suggest that also full-length mRNAs are transported within fungal EVs into plants, and these fungal mRNAs might get translated inside host cells. In this review article, we summarize the current views and fundamental concepts of extracellular RNAs released by plant-associated fungi, and we discuss new strategies to apply extracellular RNAs in crop protection against fungal pathogens. KEY POINTS: • Extracellular RNAs are an emerging topic in plant-fungal communication. • Fungi utilize RNAs to manipulate host plants for colonization. • Extracellular RNAs can be engineered to protect plants against fungal pathogens.

dsRNA-induced immunity targets plasmodesmata and is suppressed by viral movement proteins

Emerging evidence indicates that in addition to its well-recognized functions in antiviral RNA silencing, dsRNA elicits pattern-triggered immunity (PTI), likely contributing to plant resistance against virus infections. However, compared to bacterial and fungal elicitor-mediated PTI, the mode-of-action and signaling pathway of dsRNA-induced defense remain poorly characterized. Here, using multicolor in vivo imaging, analysis of GFP mobility, callose staining, and plasmodesmal marker lines in Arabidopsis thaliana and Nicotiana benthamiana, we show that dsRNA-induced PTI restricts the progression of virus infection by triggering callose deposition at plasmodesmata, thereby likely limiting the macromolecular transport through these cell-to-cell communication channels. The plasma membrane-resident SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE 1, the BOTRYTIS INDUCED KINASE1/AVRPPHB SUSCEPTIBLE1-LIKE KINASE1 kinase module, PLASMODESMATA-LOCATED PROTEINs 1/2/3, as well as CALMODULIN-LIKE 41 and Ca2+ signals are involved in the dsRNA-induced signaling leading to callose deposition at plasmodesmata and antiviral defense. Unlike the classical bacterial elicitor flagellin, dsRNA does not trigger a detectable reactive oxygen species (ROS) burst, substantiating the idea that different microbial patterns trigger partially shared immune signaling frameworks with distinct features. Likely as a counter strategy, viral movement proteins from different viruses suppress the dsRNA-induced host response leading to callose deposition to achieve infection. Thus, our data support a model in which plant immune signaling constrains virus movement by inducing callose deposition at plasmodesmata and reveals how viruses counteract this layer of immunity.

Epigenetic Control of Plant Response to Heavy Metals

Plants are sessile organisms that must adapt to environmental conditions, such as soil characteristics, by adjusting their development during their entire life cycle. In case of low-distance seed dispersal, the new generations are challenged with the same abiotic stress encountered by the parents. Epigenetic modification is an effective option that allows plants to face an environmental constraint and to share the same adaptative strategy with their progeny through transgenerational inheritance. This is the topic of the presented review that reports the scientific progress, up to date, gained in unravelling the epigenetic response of plants to soil contamination by heavy metals and metalloids, collectively known as potentially toxic elements. The effect of the microbial community inhabiting the rhizosphere is also considered, as the evidence of a transgenerational transfer of the epigenetic status that contributes to the activation in plants of response mechanisms to soil pollution.

Plant-derived nanovesicles: Further exploration of biomedical function and application potential

Extracellular vesicles (EVs) are phospholipid bilayer vesicles actively secreted by cells, that contain a variety of functional nucleic acids, proteins, and lipids, and are important mediums of intercellular communication. Based on their natural properties, EVs can not only retain the pharmacological effects of their source cells but also serve as natural delivery carriers. Among them, plant-derived nanovesicles (PNVs) are characterized as natural disease therapeutics with many advantages such as simplicity, safety, eco-friendliness, low cost, and low toxicity due to their abundant resources, large yield, and low risk of immunogenicity in vivo. This review systematically introduces the biogenesis, isolation methods, physical characterization, and components of PNVs, and describes their administration and cellular uptake as therapeutic agents. We highlight the therapeutic potential of PNVs as therapeutic agents and drug delivery carriers, including anti-inflammatory, anticancer, wound healing, regeneration, and antiaging properties as well as their potential use in the treatment of liver disease and COVID-19. Finally, the toxicity and immunogenicity, the current clinical application, and the possible challenges in the future development of PNVs were analyzed. We expect the functions of PNVs to be further explored to promote clinical translation, thereby facilitating the development of a new framework for the treatment of human diseases.

Fungal small RNAs ride in extracellular vesicles to enter plant cells through clathrin-mediated endocytosis

Small RNAs (sRNAs) of the fungal pathogen Botrytis cinerea can enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate that B. cinerea utilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). The B. cinerea tetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerous Arabidopsis clathrin-coated vesicles (CCVs) around B. cinerea infection sites and the colocalization of B. cinerea EV marker BcPLS1 and Arabidopsis CLATHRIN LIGHT CHAIN 1, one of the core components of CCV. Meanwhile, BcPLS1 and the B. cinerea-secreted sRNAs are detected in purified CCVs after infection. Arabidopsis knockout mutants and inducible dominant-negative mutants of key components of the CME pathway exhibit increased resistance to B. cinerea infection. Furthermore, Bc-sRNA loading into Arabidopsis AGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME.

Fungal small RNAs ride in extracellular vesicles to enter plant cells through clathrin-mediated endocytosis

Small RNAs (sRNAs) of the fungal pathogen Botrytis cinerea can enter plant cells and hijack host Argonaute protein 1 (AGO1) to silence host immunity genes. However, the mechanism by which these fungal sRNAs are secreted and enter host cells remains unclear. Here, we demonstrate that B. cinerea utilizes extracellular vesicles (EVs) to secrete Bc-sRNAs, which are then internalized by plant cells through clathrin-mediated endocytosis (CME). The B. cinerea tetraspanin protein, Punchless 1 (BcPLS1), serves as an EV biomarker and plays an essential role in fungal pathogenicity. We observe numerous Arabidopsis clathrin-coated vesicles (CCVs) around B. cinerea infection sites and the colocalization of B. cinerea EV marker BcPLS1 and Arabidopsis CLATHRIN LIGHT CHAIN 1, one of the core components of CCV. Meanwhile, BcPLS1 and the B. cinerea-secreted sRNAs are detected in purified CCVs after infection. Arabidopsis knockout mutants and inducible dominant-negative mutants of key components of CME pathway exhibit increased resistance to B. cinerea infection. Furthermore, Bc-sRNA loading into Arabidopsis AGO1 and host target gene suppression are attenuated in those CME mutants. Together, our results demonstrate that fungi secrete sRNAs via EVs, which then enter host plant cells mainly through CME.

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.

Identification of Long Intergenic Noncoding RNAs in Rhizoctonia cerealis following Inoculation of Wheat

Wheat sharp eyespot caused by Rhizoctonia cerealis is primarily a severe threat to worldwide wheat production. Currently, there are no resistant wheat cultivars, and the use of fungicides is the primary method for controlling this disease. Elucidating the mechanisms of R. cerealis pathogenicity can accelerate the pace of the control of this disease. Long intergenic noncoding RNAs (lincRNAs) that function in plant-pathogen interactions might provide a new perspective. We systematically analyzed lincRNAs and identified a total of 1,319 lincRNAs in R. cerealis. We found that lincRNAs are involved in various biological processes, as shown by differential expression analysis and weighted correlation network analysis (WGCNA). Next, one of nine hub lincRNAs in the blue module that was related to infection and growth processes, MSTRG.4380.1, was verified to reduce R. cerealis virulence on wheat by a host-induced gene silencing (HIGS) assay. Following that, RNA sequencing (RNA-Seq) analysis revealed that the significantly downregulated genes in the MSTRG.4380.1 knockdown lines were associated mainly with infection-related processes, including hydrolase, transmembrane transporter, and energy metabolism activities. Additionally, 23 novel microRNAs (miRNAs) were discovered during small RNA (sRNA) sequencing (sRNA-Seq) analysis of MSTRG.4380.1 knockdown, and target prediction of miRNAs suggested that MSTRG.4380.1 does not act as a competitive endogenous RNA (ceRNA). This study performed the first genome-wide identification of R. cerealis lincRNAs and miRNAs. It confirmed the involvement of a lincRNA in the infection process, providing new insights into the mechanism of R. cerealis infection and offering a new approach for protecting wheat from R. cerealis. IMPORTANCE Rhizoctonia cerealis, the primary causal agent of wheat sharp eyespot, has caused significant losses in worldwide wheat production. Since no resistant wheat cultivars exist, chemical control is the primary method. However, this approach is environmentally unfriendly and costly. RNA interference (RNAi)-mediated pathogenicity gene silencing has been proven to reduce the growth of Rhizoctonia and provides a new perspective for disease control. Recent studies have shown that lincRNAs are involved in various biological processes across species, such as biotic and abiotic stresses. Therefore, verifying the function of lincRNAs in R. cerealis is beneficial for understanding the infection mechanism. In this study, we reveal that lincRNAs could contribute to the virulence of R. cerealis, which provides new insights into controlling this pathogen.

Extracellular vesicles: cross-organismal RNA trafficking in plants, microbes, and mammalian cells

Extracellular vesicles (EVs) are membrane-enclosed nanometer-scale particles that transport biological materials such as RNAs, proteins, and metabolites. EVs have been discovered in nearly all kingdoms of life as a form of cellular communication across different cells and between interacting organisms. EV research has primarily focused on EV-mediated intra-organismal transport in mammals, which has led to the characterization of a plethora of EV contents from diverse cell types with distinct and impactful physiological effects. In contrast, research into EV-mediated transport in plants has focused on inter-organismal interactions between plants and interacting microbes. However, the overall molecular content and functions of plant and microbial EVs remain largely unknown. Recent studies into the plant-pathogen interface have demonstrated that plants produce and secrete EVs that transport small RNAs into pathogen cells to silence virulence-related genes. Plant-interacting microbes such as bacteria and fungi also secrete EVs which transport proteins, metabolites, and potentially RNAs into plant cells to enhance their virulence. This review will focus on recent advances in EV-mediated communications in plant-pathogen interactions compared to the current state of knowledge of mammalian EV capabilities and highlight the role of EVs in cross-kingdom RNA interference.

Staphylococcus aureus vaccine strategy: Promise and challenges

Staphylococcus aureus (S. aureus) is a leading and crucial infectious threat to global public health due to the widespread emergence of antibiotic-resistant strains such as Methicillin-Resistant S. aureus (MRSA). MRSA infects immunocompromised patients and healthy individuals and has rapidly spread from the healthcare setting to the outside community. The development of flawless vaccines become a medical need worldwide against multi-drug resistant S. aureus. Therefore, protection by an immune-based strategy may provide valuable measures to contain the spread of invasive S. aureus infections. Several vaccine candidates have been prepared which are either in the preclinical phase or in the early clinical phase, whereas several candidates have failed to show a protective efficacy in human subjects. Currently, research is focusing on identifying novel vaccine formulations able to elicit potent humoral and cellular immune responses. Several approaches have also been made to the development of monoclonal or polyclonal antibodies for passive immunization to protect against S. aureus infections. In recent years, a multi-epitope vaccine has emerged as a novel platform for subunit vaccine design by using computational approaches. Therefore, in this review, we have summarized and discussed the mechanistic overview of different strategies used to develop potential vaccine candidates and passive interventions which are in different stages of clinical trials to fight multi-drug resistant S. aureus infections.

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.

Beyond transcription: compelling open questions in plant RNA biology

The study of RNAs has become one of the most influential research fields in contemporary biology and biomedicine. In the last few years, new sequencing technologies have produced an explosion of new and exciting discoveries in the field but have also given rise to many open questions. Defining these questions, together with old, long-standing gaps in our knowledge, is the spirit of this article. The breadth of topics within RNA biology research is vast, and every aspect of the biology of these molecules contains countless exciting open questions. Here, we asked 12 groups to discuss their most compelling question among some plant RNA biology topics. The following vignettes cover RNA alternative splicing; RNA dynamics; RNA translation; RNA structures; R-loops; epitranscriptomics; long non-coding RNAs; small RNA production and their functions in crops; small RNAs during gametogenesis and in cross-kingdom RNA interference; and RNA-directed DNA methylation. In each section, we will present the current state-of-the-art in plant RNA biology research before asking the questions that will surely motivate future discoveries in the field. We hope this article will spark a debate about the future perspective on RNA biology and provoke novel reflections in the reader.

The mRNA mobileome: challenges and opportunities for deciphering signals from the noise

Organismal communication entails encoding a message that is sent over space or time to a recipient cell, where that message is decoded to activate a downstream response. Defining what qualifies as a functional signal is essential for understanding intercellular communication. In this review, we delve into what is known and unknown in the field of long-distance messenger RNA (mRNA) movement and draw inspiration from the field of information theory to provide a perspective on what defines a functional signaling molecule. Although numerous studies support the long-distance movement of hundreds to thousands of mRNAs through the plant vascular system, only a small handful of these transcripts have been associated with signaling functions. Deciphering whether mobile mRNAs generally serve a role in plant communication has been challenging, due to our current lack of understanding regarding the factors that influence mRNA mobility. Further insight into unsolved questions regarding the nature of mobile mRNAs could provide an understanding of the signaling potential of these macromolecules.

Targeting the Aspergillus flavus p2c gene through host-induced gene silencing reduces A. flavus infection and aflatoxin contamination in transgenic maize

Aspergillus flavus is an opportunistic fungal pathogen that infects maize and produces aflatoxins. Using biocontrol or developing resistant cultivars to reduce aflatoxin contamination has only achieved limited success. Here, the A. flavus polygalacturonase gene (p2c) was targeted for suppression through host-induced gene silencing (HIGS) to reduce aflatoxin contamination in maize. An RNAi vector carrying a portion of the p2c gene was constructed and transformed into maize B104. Thirteen out of fifteen independent transformation events were confirmed to contain p2c. The T2 generation kernels containing the p2c transgene had less aflatoxin than those without the transgene in six out of eleven events we examined. Homozygous T3 transgenic kernels from four events produced significantly less aflatoxins (P ≤ 0.02) than the kernels from the null or B104 controls under field inoculation conditions. The F1 kernels from the crosses between six elite inbred lines with P2c5 and P2c13 also supported significantly less aflatoxins (P ≤ 0.02) than those from the crosses with null plants. The reduction in aflatoxin ranged from 93.7% to 30.3%. Transgenic leaf (T0 and T3) and kernel tissues (T4) were also found to have significantly higher levels of p2c gene-specific small RNAs. Further, homozygous transgenic maize kernels had significantly less fungal growth (27~40 fold) than the null control kernels 10 days after fungal inoculation in the field. The calculated suppression of p2c gene expression based on RNAseq data was 57.6% and 83.0% in P2c5 and P2c13 events, respectively. These results indicate clearly that the reduced aflatoxin production in the transgenic kernels is due to RNAi-based suppression of p2c expression, which results in reduced fungal growth and toxin production.

Plant-derived nanoparticles and plant virus nanoparticles: Bioactivity, health management, and delivery potential

Natural plants have acquired an increasing attention in biomedical research. Recent studies have revealed that plant-derived nanoparticles (PDNPs), which are nano-sized membrane vesicles released by plants, are one of the important material bases for the health promotion of natural plants. A great deal of research in this field has focused on nanoparticles derived from fresh vegetables and fruits. Generally, PDNPs contain lipids, proteins, nucleic acids, and other active small molecules and exhibit unique biological regulatory activity and editability. Specifically, they have emerged as important mediators of intercellular communication, and thus, are potentially suitable for therapeutic purposes. In this review, PDNPs were extensively explored; by evaluating them systematically starting from the origin and isolation, toward their characteristics, including morphological compositions, biological functions, and delivery potentials, as well as distinguishing them from plant-derived exosomes and highlighting the limitations of the current research. Meanwhile, we elucidated the variations in PDNPs infected by pathogenic microorganisms and emphasized on the biological functions and characteristics of plant virus nanoparticles. After clarifying these problems, it is beneficial to further research on PDNPs in the future and develop their clinical application value.

Extracellular Vesicles of the Plant Pathogen Botrytis cinerea

Fungal secretomes are known to contain a multitude of components involved in nutrition, cell growth or biotic interactions. Recently, extra-cellular vesicles have been identified in a few fungal species. Here, we used a multidisciplinary approach to identify and characterize extracellular vesicles produced by the plant necrotroph Botrytis cinerea. Transmission electron microscopy of infectious hyphae and hyphae grown in vitro revealed extracellular vesicles of various sizes and densities. Electron tomography showed the co-existence of ovoid and tubular vesicles and pointed to their release via the fusion of multi-vesicular bodies with the cell plasma membrane. The isolation of these vesicles and exploration of their protein content using mass spectrometry led to the identification of soluble and membrane proteins involved in transport, metabolism, cell wall synthesis and remodeling, proteostasis, oxidoreduction and traffic. Confocal microscopy highlighted the capacity of fluorescently labeled vesicles to target cells of B. cinerea, cells of the fungus Fusarium graminearum, and onion epidermal cells but not yeast cells. In addition, a specific positive effect of these vesicles on the growth of B. cinerea was quantified. Altogether, this study broadens our view on the secretion capacity of B. cinerea and its cell-to-cell communication.

Molecular membrane separation: plants inspire new technologies

Plants draw up their surrounding soil solution to gain water and nutrients required for growth, development and reproduction. Obtaining adequate water and nutrients involves taking up both desired and undesired elements from the soil solution and separating resources from waste. Desirable and undesirable elements in the soil solution can share similar chemical properties, such as size and charge. Plants use membrane separation mechanisms to distinguish between different molecules that have similar chemical properties. Membrane separation enables distribution or retention of resources and efflux or compartmentation of waste. Plants use specialised membrane separation mechanisms to adapt to challenging soil solution compositions and distinguish between resources and waste. Coordination and regulation of these mechanisms between different tissues, cell types and subcellular membranes supports plant nutrition, environmental stress tolerance and energy management. This review considers membrane separation mechanisms in plants that contribute to specialised separation processes and highlights mechanisms of interest for engineering plants with enhanced performance in challenging conditions and for inspiring the development of novel industrial membrane separation technologies. Knowledge gained from studying plant membrane separation mechanisms can be applied to developing precision separation technologies. Separation technologies are needed for harvesting resources from industrial wastes and transitioning to a circular green economy.

Manipulation of the Host Endomembrane System by Bacterial Effectors

The endomembrane system, extending from the nuclear envelope to the plasma membrane, is critical to the plant response to pathogen infection. Synthesis and transport of immunity-related proteins and antimicrobial compounds to and from the plasma membrane are supported by conventional and unconventional processes of secretion and internalization of vesicles, guided by the cytoskeleton networks. Although plant bacterial pathogens reside mostly in the apoplast, major structural and functional modifications of the endomembrane system in the host cell occur during bacterial infection. Here, we review the dynamics of these cellular compartments, briefly, for their essential contributions to the plant defense responses and, in parallel, for their emerging roles in bacterial pathogenicity. We further focus on Pseudomonas syringae, Xanthomonas spp., and Ralstonia solanacearum type III secreted effectors that one or both localize to and associate with components of the host endomembrane system or the cytoskeleton network to highlight the diversity of virulence strategies deployed by bacterial pathogens beyond the inhibition of the secretory pathway. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Pathogen-Derived Extracellular Vesicles: Emerging Mediators of Plant-Microbe Interactions

Extracellular vesicles (EVs) are lipid bilayer-enclosed nanoparticles that deliver bioactive proteins, nucleic acids, lipids, and other small molecules from donor to recipient cells. They have attracted significant interest recently due to their important roles in regulating plant-microbe interaction. During microbial infection, plant EVs play a prominent role in defense by delivering small regulatory RNA into pathogens, resulting in the silencing of pathogen virulence genes. Pathogens also deliver small RNAs into plant cells to silence host immunity genes. Recent evidence indicates that microbial EVs may be involved in pathogenesis and host immunity modulation by transporting RNAs and other biomolecules. However, the biogenesis and function of microbial EVs in plant-microbe interaction remain ill-defined. In this review, we discuss various aspects of microbial EVs, with a particular focus on current methods for EV isolation, composition, biogenesis, and their roles in plant-microbe interaction. We also discussed the potential role of microbial EVs in cross-kingdom RNA trafficking from pathogens to plants, as it is a highly likely possibility to explore in the future. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Artificial nanovesicles for dsRNA delivery in spray-induced gene silencing for crop protection

Spray-induced gene silencing (SIGS) is an innovative and eco-friendly technology where topical application of pathogen gene-targeting RNAs to plant material can enable disease control. SIGS applications remain limited because of the instability of RNA, which can be rapidly degraded when exposed to various environmental conditions. Inspired by the natural mechanism of cross-kingdom RNAi through extracellular vesicle trafficking, we describe herein the use of artificial nanovesicles (AVs) for RNA encapsulation and control against the fungal pathogen, Botrytis cinerea. AVs were synthesized using three different cationic lipid formulations, DOTAP + PEG, DOTAP and DODMA, and examined for their ability to protect and deliver double stranded RNA (dsRNA). All three formulations enabled dsRNA delivery and uptake by B. cinerea. Further, encapsulating dsRNA in AVs provided strong protection from nuclease degradation and from removal by leaf washing. This improved stability led to prolonged RNAi-mediated protection against B. cinerea both on pre- and post-harvest plant material using AVs. Specifically, the AVs extended the protection duration conferred by dsRNA to 10 days on tomato and grape fruits and to 21 days on grape leaves. The results of this work demonstrate how AVs can be used as a new nanocarrier to overcome RNA instability in SIGS for crop protection.

Challenges and Opportunities for Extracellular Vesicles in Clinical Oncology Therapy

Extracellular vesicles (EVs) are membrane-bound vesicles that can be released by all cell types. They may have different biogenesis, physical features, and cargo. EVs are important biomarkers for the diagnosis and prediction of many diseases due to their essential role in intercellular communication, their highly variable cargoes, and their accumulation in various body fluids. These natural particles have been investigated as potential therapeutic materials for many diseases. In our previous studies, the clinical usage of tumor-cell-derived microparticles (T-MPs) as a novel medication delivery system was examined. This review summarizes the clinical translation of EVs and related clinical trials, aiming to provide suggestions for safer and more effective oncology therapeutic systems, particularly in biotherapeutic and immunotherapeutic systems.

Artificial nanovesicles for dsRNA delivery in spray induced gene silencing for crop protection

Spray-Induced Gene Silencing (SIGS) is an innovative and eco-friendly technology where topical application of pathogen gene-targeting RNAs to plant material can enable disease control. SIGS applications remain limited because of the instability of dsRNA, which can be rapidly degraded when exposed to various environmental conditions. Inspired by the natural mechanism of cross-kingdom RNAi through extracellular vesicle trafficking, we describe herein the use of artificial nanovesicles (AVs) for dsRNA encapsulation and control against the fungal pathogen, Botrytis cinerea. AVs were synthesized using three different cationic lipid formulations, DOTAP + PEG, DOTAP, and DODMA, and examined for their ability to protect and deliver dsRNA. All three formulations enabled dsRNA delivery and uptake by B. cinerea. Further, encapsulating dsRNA in AVs provided strong protection from nuclease degradation and from removal by leaf washing. This improved stability led to prolonged RNAi-mediated protection against B. cinerea both on pre- and post-harvest plant material using AVs. Specifically, the AVs extended the protection duration conferred by dsRNA to 10 days on tomato and grape fruits and to 21 days on grape leaves. The results of this work demonstrate how AVs can be used as a new nanocarrier to overcome dsRNA instability in SIGS for crop protection.

Serum-Exosome-Derived miRNAs Serve as Promising Biomarkers for HCC Diagnosis

BACKGROUND

Serum exosomes are emerging as key liquid biopsy biomarkers for the early diagnosis of cancer. However, the proportion and distribution of small RNA (sRNA) species from serum exosomes of hepatocellular carcinoma (HCC) patients remain unclear. Effective and reliable biomarkers for HCC diagnosis should be explored.

METHODS

In this study, we aimed to use sRNA sequencing to profile the sRNAs of serum exosomes in HCC and non-tumor donors. The serum exosomes of 124 HCC patients and 46 non-tumor donors were enrolled for detecting the values of the potential biomarkers for the diagnosis of HCC.

RESULTS

We found that miRNAs accounted for the maximal percentage of all types of sRNAs both in the serum exosomes of HCC patients and non-tumor donors. This indicated that the serum-exosome-derived microRNAs (miRNAs) were the most valuable as potential biomarkers in HCC diagnosis. Then, miRNAs were set as research candidates. In our Chinese cohorts, three serum-exosome-derived miRNAs (miR-122-5p, let-7d-5p, and miR-425-5p) could be promising biomarkers for distinguishing HCC patients from non-tumor donors. In addition, they were preferred for the early diagnosis of HCC. We also presented the base distribution of some novel serum-exosome-derived miRNAs and described the potential values as biomarkers.

CONCLUSIONS

The results suggested that the serum-exosome-derived miRNAs were the most crucial sRNA species and they highlighted the potential of serum-exosome-derived miRNAs as promising biomarkers for HCC diagnosis.

Fungal Secondary Metabolites and Small RNAs Enhance Pathogenicity during Plant-Fungal Pathogen Interactions

Fungal plant pathogens use proteinaceous effectors as well as newly identified secondary metabolites (SMs) and small non-coding RNA (sRNA) effectors to manipulate the host plant's defense system via diverse plant cell compartments, distinct organelles, and many host genes. However, most molecular studies of plant-fungal interactions have focused on secreted effector proteins without exploring the possibly equivalent functions performed by fungal (SMs) and sRNAs, which are collectively known as "non-proteinaceous effectors". Fungal SMs have been shown to be generated throughout the plant colonization process, particularly in the early biotrophic stages of infection. The fungal repertoire of non-proteinaceous effectors has been broadened by the discovery of fungal sRNAs that specifically target plant genes involved in resistance and defense responses. Many RNAs, particularly sRNAs involved in gene silencing, have been shown to transmit bidirectionally between fungal pathogens and their hosts. However, there are no clear functional approaches to study the role of these SM and sRNA effectors. Undoubtedly, fungal SM and sRNA effectors are now a treasured land to seek. Therefore, understanding the role of fungal SM and sRNA effectors may provide insights into the infection process and identification of the interacting host genes that are targeted by these effectors. This review discusses the role of fungal SMs and sRNAs during plant-fungal interactions. It will also focus on the translocation of sRNA effectors across kingdoms, the application of cross-kingdom RNA interference in managing plant diseases and the tools that can be used to predict and study these non-proteinaceous effectors.

Do photosynthetic cells communicate with each other during cell death? From cyanobacteria to vascular plants

As in metazoans, life in oxygenic photosynthetic organisms relies on the accurate regulation of cell death. During development and in response to the environment, photosynthetic cells activate and execute cell death pathways that culminate in the death of a specific group of cells, a process known as regulated cell death (RCD). RCD control is instrumental, as its misregulation can lead to growth penalties and even the death of the entire organism. Intracellular molecules released during cell demise may act as 'survival' or 'death' signals and control the propagation of cell death to surrounding cells, even in unicellular organisms. This review explores different signals involved in cell-cell communication and systemic signalling in photosynthetic organisms, in particular Ca2+, reactive oxygen species, lipid derivates, nitric oxide, and eATP. We discuss their possible mode-of-action as either 'survival' or 'death' molecules and their potential role in determining cell fate in neighbouring cells. By comparing the knowledge available across the taxonomic spectrum of this coherent phylogenetic group, from cyanobacteria to vascular plants, we aim at contributing to the identification of conserved mechanisms that control cell death propagation in oxygenic photosynthetic organisms.

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.