Lactadherin immunoblockade in small extracellular vesicles inhibits sEV-mediated increase of pro-metastatic capacities

Background Tumor-derived small extracellular vesicles (sEVs) can promote tumorigenic and metastatic capacities in less aggressive recipient cells mainly through the biomolecules in their cargo. However, despite recent advances, the specific molecules orchestrating these changes are not completely defined. Lactadherin is a secreted 0protein typically found in the milk fat globule membrane. Its overexpression has been associated with increased tumorigenesis and metastasis in breast cancer (BC) and other tumors. However, neither its presence in sEVs secreted by BC cells, nor its role in sEV-mediated intercellular communication have been described. The present study focused on the role of lactadherin-containing sEVs from metastatic MDA-MB-231 triple-negative BC (TNBC) cells (sEV-MDA231) in the promotion of pro-metastatic capacities in non-tumorigenic and non-metastatic recipient cells in vitro, as well as their pro-metastatic role in a murine model of peritoneal carcinomatosis. Results We show that lactadherin is present in sEVs secreted by BC cells and it is higher in sEV-MDA231 compared with the other BC cell-secreted sEVs measured through ELISA. Incubation of non-metastatic recipient cells with sEV- MDA231 increases their migration and, to some extent, their tumoroid formation capacity but not their anchorage-independent growth. Remarkably, lactadherin blockade in sEV-MDA231 results in a significant decrease of those sEV-mediated changes in vitro. Similarly, intraperitoneally treatment of mice with MDA-MB-231 BC cells and sEV-MDA231 greatly increase the formation of malignant ascites and tumor micronodules, effects that were significantly inhibited when lactadherin was previously blocked in those sEV-MDA231. Conclusions As to our knowledge, our study provides the first evidence on the role of lactadherin in metastatic BC cell-secreted sEVs as promoter of: (i) metastatic capacities in less aggressive recipient cells, and ii) the formation of malignant ascites and metastatic tumor nodules. These results increase our understanding on the role of lactadherin in sEVs as promoter of metastatic capacities which can be used as a therapeutic option for BC and other malignancies.

Research progress on the relationship between extracellular vesicles and male infertility / 中国综合临床

Infertility is gradually becoming a major problem affecting health worldwide, and male factors also play an important role in infertility. Extracellular vesicles (EVs) are ultramicro membranous vesicles released by cells during activation or apoptosis, which play an important role in cell communication. Relevant studies have shown that extracellular vesicles contain a variety of bioactive substances and participate in infertility related pathophysiological processes by influencing the content of intercellular transmission. Therefore, we reviewed the relationship between extracellular vesicles and male infertility, and expounded the occurrence and potential treatment of male infertility from another perspective.

Recent progress in aptamer-based microfluidics for the detection of circulating tumor cells and extracellular vesicles / 药物分析学报

Liquid biopsy is a technology that exhibits potential to detect cancer early,monitor therapies,and predict cancer prognosis due to its unique characteristics,including noninvasive sampling and real-time analysis.Circulating tumor cells(CTCs)and extracellular vesicles(EVs)are two important components of circu-lating targets,carrying substantial disease-related molecular information and playing a key role in liquid biopsy.Aptamers are single-stranded oligonucleotides with superior affinity and specificity,and they can bind to targets by folding into unique tertiary structures.Aptamer-based microfluidic platforms offer new ways to enhance the purity and capture efficiency of CTCs and EVs by combining the advantages of microfluidic chips as isolation platforms and aptamers as recognition tools.In this review,we first briefly introduce some new strategies for aptamer discovery based on traditional and aptamer-based micro-fluidic approaches.Then,we subsequently summarize the progress of aptamer-based microfluidics for CTC and EV detection.Finally,we offer an outlook on the future directional challenges of aptamer-based microfluidics for circulating targets in clinical applications.

Characterization of platelet-derived extracellular vesicles induced by differential platelet activation pathways / 中国输血杂志

【Objective】 To investigate the effects of platelet activation pathways on the characterization of platelet-derived extracellular vesicles(PEVs). 【Methods】 Whole blood from healthy donors was prepared into platelet suspension by centrifugation. Platelets were randomly divided into six groups, the ctrl group added no extra stimulus, and the other five groups were treated with collagen, adenosine diphosphate(ADP), thrombin, Ca2+ ionophore and freeze-thaw cycles (F-T) to activate platelets. Platelet-derived exosomes(PEXOs) and microvesicles(PMVs) were isolated by differential centrifugations, and then were determined by nano-flow cytometry and electron microscopy. The protein markers of PEXOs also were identified by western-blot. The protein concentration and content of PEXOs were also detected. 【Results】 CD9, CD81, TSG101 proteins were detected in all of the PEXOs, which had no calnexin. Both PEXOs and PMVs had CD41; PEXOs were cup-holder-like bilayer membrane vesicles under a transmission electron microscope, while PMVs were irregular membranous structure; 85%-95% of PEXOs were<100nm, 87%-94% of PMVs were 100-300nm. The concentration of exosomes and microvesicles in the F-T group was the highest(205.67±65.27 and 102.73±15.48), followed by the Ca2+ ionophore group(44.42±17.07 and 11.4±4.81). Although in the same size range, the numbers of PEVs induced by different activation conditions varied. The protein concentration of PEXOs in the F-T group(1.11±0.51) was higher than that in the control group(0.32±0.39), ADP group(0.41±0.31) and thrombin group(0.38±0.37), while the total protein(125.40±58.32) was higher than that in other three groups(the ctrl group 25.53±25.96 vs ADP group 37.21±15.73 vs thrombin group 36.28±24.18 vs Ca2+ ionophore group 47.09±23.29). 【Conclusion】 The biological characteristics of PEVs are affected by platelets activation pathways, whose ability to induce protein-packing into exosomes may also be relevant to the particle size. The freeze-thaw cycles can induce high concentrations of extracellular vesicles, which may be an ideal method for the preparation of PEVs.

Non clinical evaluation strategy based on extracellular vesicle therapy / 中国生物制品学杂志

@#The concept of extracellular vesicles(EV) was proposed in 2011 by the International Society for Extracellular Vesicles(ISEV),and EV can be widely used in various fields of disease treatment as therapeutic drugs and drug delivery carriers.The therapy based on EV may become a new model of disease treatment in addition to traditional drug therapy and cell therapy-EV cell-free therapy.As a vector,compared with viral vector and synthetic non viral vector,EV have unique advantages and great potential.However,EV have some challenges in clinical transformation because of their unique biological properties.Moreover,this field is relatively new,and there are no relevant policies and regulations specifically for EV therapy.By collecting information from ClinicalTrials.gov platform,this paper summarized the research progress based on EV therapy,put forward suggestions for the existing regulatory system,discussed the general principles of EV non clinical research,pharmaceutical research,pharmacodynamics and pharmacokinetics research,safety evaluation and other non clinical evaluation strategies,so as to provide reference for the formulation of non clinical evaluation research scheme based on EV therapy.

Differential proteomic profiling of breast milk-derived extracellular vesicles from mothers of preterm and term infants / 中华围产医学杂志

Objective:To analyze the differential expression of breast milk-derived extracellular vesicles (BM-EV) from mothers of preterm and term infants .Methods:Breast milk samples were collected from preterm and term delivery (three cases in each) at the Women's Hospital of Nanjing Medical University in 2019. BM-EV was extracted using ultracentrifugation. After preliminary identification of the characteristics of BM-EV, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for protein quantification. Significantly up-regulated differential proteins (fold change≥1.5 and P<0.05) in the preterm group were screened. GO and KEGG were performed to predict the differentially expressed proteins' functional annotation and determine associated signaling pathways. Mann-Whitney U test and Fisher's exact test were used for intergroup comparisons. Pearson's correlation test describes the correlation of protein quantification values between samples. The differences in protein abundance were compared between the two groups using a t-test, followed by multiple corrections. Additionally, significantly enriched GO terms and KEGG pathways of the differentially expressed proteins were screened based on the hypergeometric distribution. Results:(1) There were three primiparae in the preterm group and one in the term group. Marker proteins CD9, CD81, and HSP70 were enriched in the BM-EV of both groups. (2) Six samples were comparable between groups and showed high reproducibility within groups. The correlation of protein quantification values between samples was up to 0.99. Furthermore, the coefficient of variation was 11.21% for preterm samples and 19.72% for term, and the data values in the preterm group were relative. (3) A total of 945 proteins were identified, and 156 were differentially expressed between preterm and term BM-EV, with 83 significantly up-regulated in preterm BM-EV. In the up-regulated proteins, the top three high-abundance proteins were complemented C4a, fatty acid synthase, and sclerostin domain-containing protein-1. (4) The biological processes or cellular components with the highest enrichment in GO functional prediction were mainly involved in hemoglobin and glycogen biosynthesis, immunological synapse formation, and phagocytosis mediated by the Fc γ receptor signaling pathway. The most relevant KEGG pathways were ribosome-related, complement and coagulation cascades, neutrophil extracellular trap formation, and Fc γ receptor-mediated phagocytosis.Conclusion:The significantly up-regulated differential proteins in BM-EV may play a protective role by regulating immunity, gastrointestinal function, and energy metabolism in preterm infants.

Research on cell membrane-coated drug delivery nanovesicles in inducing the polarization of tumor-associated macrophages and treating osteosarcoma / 中华骨科杂志

Objective:To prepare cell membrane-coated nanovesicles with targeted delivery of toll-like receptor 4 (TLR4) agonist, and to explore the effect and mechanism of inducing the polarization of tumor-associated macrophages (TAMs) and treating osteosarcoma.Methods:TLR4 agonist loaded nanovesicles were prepared by polycarbonate membrane extruders. The morphology and size of nanovesicles were detected by transmission electron microscopy (TEM) and particle size analyzer, and the drug loading performance of the nanovesicles to TLR4 agonist was investigated. TLR4 agonist loaded nanovesicles were co-incubated with macrophages in vitro, and the targeting ability of nanovesicles to macrophages and its role in regulating the function of macrophages were detected by confocal fluorescence microscopy. In vitro experiments, a cell co-culture system was established. After the upper layer macrophages were treated by the control group, the TLR4 agonist group and the TLR4 agonist loaded nanovesicle group, the lower layer osteosarcoma cells were collected for CCK-8 and cloning formation experiments to evaluate their effects on the proliferation and migration of osteosarcoma cells. In vivo experiments, an osteosarcoma subcutaneous graft tumor model was established, and mice were randomly divided into the control group, the TLR4 agonist group, and the TLR4 agonist loaded nanovesicle group. After the treatment by caudal vein, the tumor targeting ability of nanovesicles in vivo was explored through the in vivo imaging system, and the volume of tumor tissue was continuously detected. The subcutaneous tumors were stained to detect macrophage-related markers, and their effect on the polarization of macrophages was evaluated. The TUNEL fluorescence of tumor tissues was further detected.Results:TEM showed the round shape of TLR4 agonist loaded nanovesicle and the size was about 200 nm. The co-incubation of 0.05 mg TLR4 agonist with 0.1 mg nanovesicles was the best condition for the preparation of drug-loaded nanovesicles. The drug loading efficiency was about 35% and the drug loading content was about 0.11 mg/mg. The membrane-coated nanovesicles could efficiently load and deliver TLR4 agonist. TLR4 agonist loaded nanovesicles were labeled with DiD red fluorescent dye, and then the labeled nanovesicles were co-incubated with macrophages. It was found by confocal fluorescence microscopy that DiD labeled TLR4 agonist loaded nanovesicles significantly accumulated in macrophages, and the fluorescence of M1-type macrophage marker (iNOS) was significantly enhanced, which could induce M1 polarization of macrophages. In vitro experiments, it was found that the number of osteosarcoma cells in the TLR4 agonist loaded nanovesicle group was significantly reduced under the light microscope, and the cell morphology was wrinkled and rounded. CCK-8 and cloning formation experiments showed that the proliferation and migration ability of osteosarcoma cells in the TLR4 agonist loaded nanovesicle group was significantly reduced compared with the control group and the TLR4 agonist group. A subcutaneous graft tumor model was established. In vivo imaging experiments showed that TLR4 agonist loaded nanovesicles locally accumulated in tumor tissues in vivo, but were not distributed in other organs. The growth of tumor tissue was significantly inhibited in the TLR4 agonist loaded nanovesicle group. Moreover, the fluorescence of M1-type macrophage marker (iNOS) was significantly enhanced (relative fluorescence intensity: 3.27±0.19), while the fluorescence of M2-type macrophage marker (CD163) was significantly decreased (relative fluorescence intensity: 0.14±0.04). TUNEL fluorescence staining showed that the apoptosis level of osteosarcoma cells was significantly increased (relative fluorescence intensity: 9.53±0.21).Conclusion:Membrane-coated nanovesicles could targeted deliver TLR4 agonist to osteosarcoma, induce TAMspolarization, remodel tumor immunosuppressive microenvironment, promote cell apoptosis, and effectively kill osteosarcoma.

Research progress of mesenchymal stem cell-derived extracellular vesicles in liver diseases / 中华肝脏病杂志

Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) transport and transmit intercellular information and play an essential role in physiological and pathological processes. MSC-EVs, MSC-EVs-microRNA, and genetically modified MSC-EVs are involved in the onset and progression of different liver diseases and play a role in reducing liver cell damage, promoting liver cell regeneration, inhibiting liver fibrosis, regulating liver immunity, alleviating liver oxidative stress, inhibiting liver cancer occurrence, and others. Hence, it will replace MSCs as a research hotspot for cell-free therapy. This article reviews the research progress of MSC-EVs in liver diseases and provides a new basis for cell-free therapy of clinical liver diseases.

A novel mesenchymal stem cell-based regimen for acute myeloid leukemia differentiation therapy

Currently the main treatment of acute myeloid leukemia (AML) is chemotherapy combining hematopoietic stem cell transplantation. However, the unbearable side effect of chemotherapy and the high risk of life-threatening infections and disease relapse following hematopoietic stem cell transplantation restrict its application in clinical practice. Thus, there is an urgent need to develop alternative therapeutic tactics with significant efficacy and attenuated adverse effects. Here, we revealed that umbilical cord-derived mesenchymal stem cells (UC-MSC) efficiently induced AML cell differentiation by shuttling the neutrophil elastase (NE)-packaged extracellular vesicles (EVs) into AML cells. Interestingly, the generation and release of NE-packaged EVs could be dramatically increased by vitamin D receptor (VDR) activation in UC-MSC. Chemical activation of VDR by using its agonist 1α,25-dihydroxyvitamin D3 efficiently enhanced the pro-differentiation capacity of UC-MSC and then alleviated malignant burden in AML mouse model. Based on these discoveries, to evade the risk of hypercalcemia, we synthetized and identified sw-22, a novel non-steroidal VDR agonist, which exerted a synergistic pro-differentiation function with UC-MSC on mitigating the progress of AML. Collectively, our findings provided a non-gene editing MSC-based therapeutic regimen to overcome the differentiation blockade in AML.

Cell-derived nanovesicles from mesenchymal stem cells as extracellular vesicle-mimetics in wound healing

Wound healing is a dynamic process that involves a series of molecular and cellular events aimed at replacing devitalized and missing cellular components and/or tissue layers. Recently, extracellular vesicles (EVs), naturally cell-secreted lipid membrane-bound vesicles laden with biological cargos including proteins, lipids, and nucleic acids, have drawn wide attention due to their ability to promote wound healing and tissue regeneration. However, current exploitation of EVs as therapeutic agents is limited by their low isolation yields and tedious isolation processes. To circumvent these challenges, bioinspired cell-derived nanovesicles (CDNs) that mimic EVs were obtained by shearing mesenchymal stem cells (MSCs) through membranes with different pore sizes. Physical characterisations and high-throughput proteomics confirmed that MSC-CDNs mimicked MSC-EVs. Moreover, these MSC-CDNs were efficiently uptaken by human dermal fibroblasts and demonstrated a dose-dependent activation of MAPK signalling pathway, resulting in enhancement of cell proliferation, cell migration, secretion of growth factors and extracellular matrix proteins, which all promoted tissue regeneration. Of note, MSC-CDNs enhanced angiogenesis in human dermal microvascular endothelial cells in a 3D PEG-fibrin scaffold and animal model, accelerating wound healing in vitro and in vivo. These findings suggest that MSC-CDNs could replace both whole cells and EVs in promoting wound healing and tissue regeneration.

Click chemistry extracellular vesicle/peptide/chemokine nanocarriers for treating central nervous system injuries

Central nervous system (CNS) injuries, including stroke, traumatic brain injury, and spinal cord injury, are essential causes of death and long-term disability and are difficult to cure, mainly due to the limited neuron regeneration and the glial scar formation. Herein, we apply extracellular vesicles (EVs) secreted by M2 microglia to improve the differentiation of neural stem cells (NSCs) at the injured site, and simultaneously modify them with the injured vascular targeting peptide (DA7R) and the stem cell recruiting factor (SDF-1) on their surface via copper-free click chemistry to recruit NSCs, inducing their neuronal differentiation, and serving as the nanocarriers at the injured site (Dual-EV). Results prove that the Dual-EV could target human umbilical vascular endothelial cells (HUVECs), recruit NSCs, and promote the neuronal differentiation of NSCs in vitro. Furthermore, 10 miRNAs are found to be upregulated in Dual-M2-EVs compared to Dual-M0-EVs via bioinformatic analysis, and further NSC differentiation experiment by flow cytometry reveals that among these miRNAs, miR30b-3p, miR-222-3p, miR-129-5p, and miR-155-5p may exert effect of inducing NSC to differentiate into neurons. In vivo experiments show that Dual-EV nanocarriers achieve improved accumulation in the ischemic area of stroke model mice, potentiate NSCs recruitment, and increase neurogenesis. This work provides new insights for the treatment of neuronal regeneration after CNS injuries as well as endogenous stem cells, and the click chemistry EV/peptide/chemokine and related nanocarriers for improving human health.

Exosomes and cystic echinococcosis: systematic review / Exosomas y equinococosis quística: revisión sistemática

SUMMARY: Exosomes are small and single-membrane secreted organelles, up to 200 nm in diameter that have the same topology as the cell, but are enriched in proteins, nucleic acids, lipids, and glycoconjugates. It can be found in any type of body fluids such as plasma, urine, saliva, sperm, bile, etc. On the other hand, cystic Echinococcosis (CE) has been studied from different points of view, among others, from genomics and proteomics, and the presence of CE exosomes in humans and other intermediate hosts has been reported in very few articles. The aim of this review was to report the evidence available regarding exosomes and CE. Systematic review. Data sources: Trip Database, SciELO, WoS, MEDLINE, EMBASE and SCOPUS. Eligibility criteria: Studies related to CEin any type of host and state of the parasite, without language restriction, published between 1966-2021. Variables: Year of publication, geographical origin, species isolated, location of exosomes. Forty-two studies were initially identified. After scrutinizing titles and abstracts, checking duplications and in-depth analysis of the studies selected, 12 articles including human, bovine, sheep, dog samples were also included. All were case reports or case series. The highest proportion of articles was published between 2019 and 2021 (58.3 %). Publications were predominantly from China (58.3 %). Evidence about exosomes and CE is scarce and reduced range of articles and cases.

RESUMEN: Los exosomas son orgánulos pequeños y secretados por una sola membrana, de hasta 200 nm de diámetro que tienen la misma topología que la célula, pero están enriquecidos en proteínas, ácidos nucleicos, lípidos y glicoconjugados. Se puede encontrar en cualquier tipo de fluidos corporales como plasma, orina, saliva, esperma, bilis, etc. Por otro lado, la equinococosis quística (CE) ha sido estudiada desde diferentes puntos de vista, entre otros, desde la genómica y proteómica, y la presencia de exosomas de CE en humanos y otros huéspedes intermediarios se ha informado en muy pocos artículos. El objetivo de esta revisión fue informar la evidencia disponible con respecto a los exosomas y la CE. Revisión sistemática. Fuentes de datos: Trip Database, SciELO, WoS, MEDLINE, EMBASE y SCOPUS. Criterios de elegibilidad: Estudios relacionados con la EC en cualquier tipo de hospedador y estado del parásito, sin restricción de idioma, publicados entre 1966-2021. Variables: año de publicación, origen geográfico, especie aislada, ubicación de exosomas. Se identificaron inicialmente 42 estudios. Después de examinar los títulos y resúmenes, verificar las duplicaciones y analizar en profundidad los estudios seleccionados, se incluyeron 12 artículos que incluían muestras de humanos, bovinos, ovinos y caninos. Todos fueron informes de casos o series de casos. La mayor proporción de artículos se publicó entre 2019 y 2021 (58,3 %). Las publicaciones fueron predominantemente de China (58,3 %). La evidencia sobre exosomas y CE es escasa y la gama de artículos y casos es reducida.

Paternal environmental exposure-induced spermatozoal small noncoding RNA alteration meditates the intergenerational epigenetic inheritance of multiple diseases / 医学前沿

Studies of human and mammalian have revealed that environmental exposure can affect paternal health conditions as well as those of the offspring. However, studies that explore the mechanisms that meditate this transmission are rare. Recently, small noncoding RNAs (sncRNAs) in sperm have seemed crucial to this transmission due to their alteration in sperm in response to environmental exposure, and the methodology of microinjection of isolated total RNA or sncRNAs or synthetically identified sncRNAs gradually lifted the veil of sncRNA regulation during intergenerational inheritance along the male line. Hence, by reviewing relevant literature, this study intends to answer the following research concepts: (1) paternal environmental factors that can be passed on to offspring and are attributed to spermatozoal sncRNAs, (2) potential role of paternal spermatozoal sncRNAs during the intergenerational inheritance process, and (3) the potential mechanism by which spermatozoal sncRNAs meditate intergenerational inheritance. In summary, increased attention highlights the hidden wonder of spermatozoal sncRNAs during intergenerational inheritance. Therefore, in the future, more studies should focus on the origin of RNA alteration, the target of RNA regulation, and how sncRNA regulation during embryonic development can be sustained even in adult offspring.

Proteomic characterization of platelet-derived extracellular vesicles induced by different activation pathways / 中国输血杂志

Activated platelets secrete bioactive molecules and extracellular vesicles. Platelet-derived extracellular vesicles(PEVs), which are rich in proteins, have become important mediators of intercellular communication and cargo exchange, being involved in not only hemostasis and thrombosis, but also in immunity and tissue repair. In past decades, many advances have been made in the isolation, characterization and application of PEVs. Platelet activation modes influence the proteomic features of formed extracellular vesicles. The activation ways may be closely related to functional differences. This review summarized the proteomics and functions of PEVs induced by different platelet activation pathways.

Research progress on salivary exosomes and oral diseases / 口腔疾病防治

@#Salivary exosomes are extracellular vesicles with a diameter of 30-50 nm in saliva. With the development of technology in recent years, many studies have revealed that salivary exosomes play an important role in the occurrence and development of various oral diseases. For example, salivary exosomal CD9 and CD81 promote tumor cell metastasis by regulating the cell adhesion and movement, salivary exosomal miR-24-3p promotes the tumor cell proliferation by acting on PER1, and salivary exosomal programmed cell death-ligand 1 (PD-L1) mRNA inhibits the destruction of inflammatory tissue, which can be biomarkers for the diagnosis of oral cancer, periodontitis and other oral diseases. Therefore, salivary exosomes can be used as potential prognostic and diagnostic markers for oral diseases. In addition to oral diseases, such as oral cancer, periodontitis, oral lichen planus, Sjogren’s syndrome, etc., salivary exosomes are closely related to distant tumors, such as pancreatic cancer, lung cancer, and systemic diseases, such as Parkinson’s disease, inflammatory bowel disease, etc. It is of great significance to study the role of salivary exosomes in the diagnosis and treatment of oral and systemic diseases and to develop the potential of salivary exosomes as biomarkers for disease diagnosis.

The extracellular vesicles from gram-positive bacteria: a review / 生物工程学报

Extracellular vesicles (EVs), also known as membrane vesicles, are vesicular bodies secreted by eukaryotic cells and bacteria. EVs can carry proteins, DNA, RNA, and various metabolites for the exchange and transmission of substances between cells. They play contents-dependent physiological functions, such as delivering nutrients, participating in immune response, and treating cancers. Currently, most studies focus on the exploration of vesicles secreted by eukaryotic cells and gram-negative bacteria, while few studies focus on gram-positive bacteria. This review summarized the production, content composition, physiological function, and engineering of EVs secreted by gram-positive bacteria, and prospected future perspectives in this area.

Effects and mechanisms of liver cancer cell-derived LC3B + extracellular vesicles on the exhaustion of CD8 + T cells / 中华微生物学和免疫学杂志

Objective:To investigate the potential molecular mechanisms of liver cancer cell-derived secretory autophagosomes, extracellular vesicles expressing LC3B (LC3B + EVs), in promoting the exhaustion of CD8 + T cells. Methods:The proportions of LC3B + EVs and PD-1 + CD8 + T cells in peripheral blood and ascites of liver cancer patients were measured by flow cytometry. Spearman correlation test was used to analyze the correlation between the proportions of LC3B + EVs and PD-1 + CD8 + T cells. Peripheral blood mononuclear cells (PBMCs) from healthy donors were treated with LC3B + EVs or heat shock protein 90α (HSP90α) blocking antibody-pretreated LC3B + EVs for 72 h in the presence of αCD3/CD28 antibodies and IL-2 in vitro. The proportions of PD-1 + CD8 + T and IFN-γ + CD8 + T cells and the concentrations of IL-2, TNF-α and IFN-γ in the supernatants were all detected by flow cytometry. Results:The proportions of LC3B + EVs and HSP90α + LC3B + EVs in plasma and ascites from liver cancer patients were significantly higher than those in healthy control group and non-cancerous ascites group. The level of plasma LC3B + EVs, especially HSP90α + LC3B + EVs, was significantly correlated with the percentage of exhausted PD-1 + CD8 + T cells. In addition, LC3B + EVs from human liver cancer cells up-regulated the percentage of exhausted CD8 + T cells in vitro. However, LC3B + EVs pretreated with HSP90α blocking antibody could significantly inhibit LC3B + EVs-induced CD8 + T cell exhaustion. Conclusions:Liver cancer cell-derived LC3B + EVs could effectively induce CD8 + T cell exhaustion mainly through the membrane-bound HSP90α.

Current progress of liquid biopsy in early diagnosis of hepatocellular carcinoma / 中华肝胆外科杂志

Early diagnosis of hepatocellular carcinoma (HCC) is of great significance in the management of patients. Liquid biopsy is a promising tool to use for early diagnosis of liver cancer by detecting tumor expressions through analyzing circulating tumor components such as circulating tumor DNA, circulating tumor cells and extracellular vesicles. The advantages of using liquid biopsy include easy collection of specimen samples and its good sensitivity and specificity for HCC detection. In this review, recent research progress on liquid biopsy on HCC is discussed with the aim to provide updated information on early diagnosis of HCC.

The effect of extracellular vesicles derived from lung tissue on intrapulmonary inflammation and formation of neutrophil extracellular traps in sepsis rats / 中华急诊医学杂志

Objective:To investigate the effect of extracellular vesicles derived from lung tissue on intrapulmonary inflammation and the formation of neutrophil extracellular traps (NETs) in sepsis rats.Methods:Sepsis rat model was established by cecal ligation and puncture (CLP). Collagenase D and DNase I were used to dissociate the lung tissue, the impurities were removed by centrifugation, and finally, the extracellular vesicles (Ti-EVs) derived from lung tissue were separated and extracted by differential ultracentrifugation. Eighteen male SD rats were randomly divided into the sham group, sepsis group and Ti-EVs group: in the Ti-sEV group, a sepsis model was established by CLP, and Ti-EVs suspension was instilled through the airway; rats in the CLP group received CLP, and an equal volume of PBS was instilled through the airway; and rats in the sham group was treated with sham operation. The pathological changes of lung tissue were detected by hematoxylin-eosin (HE) staining after 24 h. The content of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the bronchoalveolar lavage fluid (BALF) was measured by enzyme-linked immunosorbent assay (ELISA). Immunofluorescence was used to detect the NETs content in lung tissue.Results:The isolated extracellular vesicles derived from rat lung tissue were observed by transmission electron microscopy as double-layer circular cystic vesicles with particle diameter mainly distributed at 150 nm. Western blot showed positive expression of EVs markers CD9, CD63, and Tsg101. HE staining of lung tissue showed alveolar integrity damage and a large number of inflammatory cells infiltrated in the lung of sepsis rats. Compared with the CLP group, the degree of lung tissue damage was more serious in the Ti-EVs group and the levels of IL-1β, TNF-α and IL-6 in the BALF of rats were significantly increased ( P<0.01). The formation of NETs in the lungs of the rats in the sepsis group and the Ti-EVs group was observed under the laser confocal microscope. Compared with the sepsis group, the fluorescence intensity of NETs in the lung tissues of the Ti-EVs group increased significantly. Conclusions:After enzymatic digestion, differential ultracentrifugation and other treatments, the extracellular vesicles derived from rat lung tissue with high purity can be successfully isolated and extracted. In the process of septic lung injury, extracellular vesicles in lung tissue can aggravate the inflammatory response in the lung and promote the formation of NETs.

Neutralization of SARS-CoV-2 pseudovirus using ACE2-engineered extracellular vesicles

The spread of coronavirus disease 2019 (COVID-19) throughout the world has resulted in stressful healthcare burdens and global health crises. Developing an effective measure to protect people from infection is an urgent need. The blockage of interaction between angiotensin-converting enzyme 2 (ACE2) and S protein is considered an essential target for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) drugs. A full-length ACE2 protein could be a potential drug to block early entry of SARS-CoV-2 into host cells. In this study, a therapeutic strategy was developed by using extracellular vesicles (EVs) with decoy receptor ACE2 for neutralization of SARS-CoV-2. The EVs embedded with engineered ACE2 (EVs-ACE2) were prepared; the EVs-ACE2 were derived from an engineered cell line with stable ACE2 expression. The potential effect of the EVs-ACE2 on anti-SARS-CoV-2 was demonstrated by both in vitro and in vivo neutralization experiments using the pseudovirus with the S protein (S-pseudovirus). EVs-ACE2 can inhibit the infection of S-pseudovirus in various cells, and importantly, the mice treated with intranasal administration of EVs-ACE2 can suppress the entry of S-pseudovirus into the mucosal epithelium. Therefore, the intranasal EVs-ACE2 could be a preventive medicine to protect from SARS-CoV-2 infection. This EVs-based strategy offers a potential route to COVID-19 drug development.