BACKGROUND: Cluster of differentiation 8 positive (CD8 + ) T cells play a crucial role in the response against tumors, including hepatocellular carcinoma (HCC), where their dysfunction is commonly observed. While the association between elevated peroxisome proliferator-activated receptor alpha (PPARα) expression in HCC cells and exosomes and unfavorable prognosis in HCC patients is well-established, the underlying biological mechanisms by which PPARα induces CD8 + T cell exhaustion mediated by HCC exosomes remain poorly understood. METHODS: Bioinformatics analyses and dual-luciferase reporter assays were used to investigate the regulation of microRNA-27b-3p ( miR-27b-3p ) and thymocyte selection-associated high mobility group box ( Tox ) by Pparα . In vitro and in vivo experiments were conducted to validate the effects of HCC-derived exosomes, miR-27b-3p overexpression, and Pparα on T cell function. Exosome characterization was confirmed using transmission electron microscopy, Western blotting, and particle size analysis. Exosome tracing was performed using small animal in vivo imaging and confocal microscopy. The expression levels of miR-27b-3p , Pparα , and T cell exhaustion-related molecules ( Tox , Havcr2 , and Pdcd1 ) were detected using quantitative reverse transcription polymerase chain reaction analysis, Western blotting analysis, immunofluorescence staining, and flow cytometry analysis. RESULTS: Pparα expression was significantly increased in HCC and negatively correlated with prognosis. It showed a positive correlation with Tox and a negative correlation with miR-27b-3p . The overexpressed Pparα from HCC cells was delivered to CD8 + T cells via exosomes, which absorbed miR-27b-3p both in vitro and in vivo , acting as "miRNA sponges". Further experiments demonstrated that Pparα can inhibit the negative regulation of Tox mediated by miR-27b-3p through binding to its 3'untranslated regions. CONCLUSIONS HCC-derived exosomes deliver Pparα to T cells and promote CD8 + T cell exhaustion and malignant progression of HCC via the miR-27b-3p /TOX regulatory axis. The mechanisms underlying T-cell exhaustion in HCC can be utilized for the advancement of anticancer therapies.
MicroRNAs/metabolism* ; PPAR alpha/genetics* ; Carcinoma, Hepatocellular/genetics* ; Humans ; Liver Neoplasms/genetics* ; CD8-Positive T-Lymphocytes/immunology* ; Exosomes/metabolism* ; Animals ; Cell Line, Tumor ; Mice ; High Mobility Group Proteins/genetics* ; Male ; T-Cell Exhaustion

Objective To investigate how culture duration affects the expression of immune membrane proteins in human monocyte-derived dendritic cells (DCs) and their exosomes (DEXs). Methods Human monocytes were induced with recombinant granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4) to differentiate into DCs and were subsequently matured with tumor necrosis factor α(TNF-α). Exosomes were isolated by ultracentrifugation, and DEXs were identified by transmission electron microscopy and Amnis imaging flow cytometry, which were also used to quantify the expression of immune membrane proteins on DCs and DEXs. Results On the 10th day of culture, DCs displayed high surface expression of CD11c, CD80, CD86, major histocompatibility complex class I (MHC-I), and MHC-II. Expression peaked at day 18(CD11c: 78.66%±20.33%, CD80: 76.41%±10.02%, CD86: 96.43%±0.43%, MHC-I: 84.71%±2.96%, MHC-II: 80.01%±7.03%). After day 24, the overall expression showed a declining trend, with statistically significant differences observed for all markers except CD80 and MHC-II. By day 30, 80% of the DCs still expressed CD80, CD86, and MHC-II. The expression of immune membrane proteins on DEX surfaces also reached its peak on day 18, followed by an overall decline with prolonged culture time, with statistically significant differences observed for all markers except CD80. Correlation analysis revealed a significant positive relationship between the expression levels of immune membrane proteins on DC and DEX surfaces (CD11c: r=0.98; CD80: r=0.65; CD86: r=0.82; MHC-I: r=0.86; MHC-II: r=0.93). Conclusion Human monocyte-derived DCs in vitro express high expression of immune membrane proteins and maintain stable expression over a specific period. The exosomes secreted by these cells similarly demonstrate high surface expression of immune membrane proteins, with temporal trends aligned with those of the parent DCs.
Humans ; Dendritic Cells/immunology* ; Exosomes/immunology* ; Monocytes/metabolism* ; Cells, Cultured ; Time Factors ; B7-1 Antigen/metabolism* ; Membrane Proteins/immunology* ; Cell Culture Techniques/methods* ; B7-2 Antigen/metabolism* ; Cell Differentiation ; CD11c Antigen/metabolism* ; Granulocyte-Macrophage Colony-Stimulating Factor/pharmacology*

Exosomes are extracellular vesicles that can be secreted by various cells and widely exist in body fluids such as blood and urine. During the progression of respiratory tract diseases, exosomes derived from epithelial and immune cells can secrete substances such as RNA and proteins, disrupting the respiratory defense system and inducing or exacerbating the disease. Exosomes derived from circulating and lung tissues can be used as potential diagnostic markers for respiratory diseases, which greatly improves the diagnostic sensitivity and specificity for respiratory diseases such as tumors and infections. The treatment of respiratory diseases is also closely related to exosomes. The low immunogenicity and high compatibility of exosomes make them effective tools for delivering molecules and drugs for treatment.
Exosomes/immunology* ; Humans ; Respiratory Tract Diseases/therapy* ; Animals ; Biomarkers

Traumatic brain injury (TBI) remains a major cause of death and disability worldwide. Increasing evidence indicates that TBI is an important risk factor for neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, and chronic traumatic encephalopathy. Despite improved supportive and rehabilitative care of TBI patients, unfortunately, all late phase clinical trials in TBI have yet to yield a safe and effective neuroprotective treatment. The disappointing clinical trials may be attributed to variability in treatment approaches and heterogeneity of the population of TBI patients as well as a race against time to prevent or reduce inexorable cell death. TBI is not just an acute event but a chronic disease. Among many mechanisms involved in secondary injury after TBI, emerging preclinical studies indicate that posttraumatic prolonged and progressive neuroinflammation is associated with neurodegeneration which may be treatable long after the initiating brain injury. This review provides an overview of recent understanding of neuroinflammation in TBI and preclinical cell-based therapies that target neuroinflammation and promote functional recovery after TBI.
Age Factors ; Animals ; Brain ; immunology ; Brain Injuries, Traumatic ; complications ; therapy ; Cell- and Tissue-Based Therapy ; methods ; Exosomes ; Extracellular Vesicles ; physiology ; Female ; Humans ; Inflammation ; etiology ; Lymphatic System ; physiology ; Male ; Neuroprotective Agents ; Sex Characteristics

Mesenchymal stem cell (MSC) transplantation is considered one of the most promising therapeutic strategies for the repair of brain injuries and plays an important role in various links of nerve repair. Recent studies have shown that MSC-derived exosomes may dominate the repair of brain injuries and help to promote angiogenesis, regulate immunity, inhibit apoptosis, and repair the nerves, and therefore, they have a great potential in the treatment of brain injuries in neonates. With reference to these studies, this article reviews the mechanism of action of exosomes in the repair of brain injuries and related prospects and challenges, in order to provide new directions for the treatment of brain injuries in neonates with stem cells.
Apoptosis ; Brain Injuries ; therapy ; Exosomes ; physiology ; Humans ; Inflammation ; prevention & control ; Mesenchymal Stem Cell Transplantation ; Neovascularization, Physiologic ; T-Lymphocytes ; immunology

This study was aimed to explore the immunoregulatory function and capability supporting the angiogenesis of exosomes secreted by bone marrow mesenchymal stem cells (BMMSC) from healthy persons. Supernatant of BMMSC (P4-P6) was collected for exosome purification. Transmission electron microscopy (TEM) and Western blot were used to identify the quality of isolated exosomes. The amount of exosomes was quantified through bicinchoninic acid (BCA) protein assay. Human peripheral blood mononuclear cells (PBMNC) were isolated from healthy donor and added with isolating exosomes. After co-cultured for 72 h, IFN-γ from the co-culture system was detected by ELISA. The expression of miRNA-associated with immunity were detected by real-time reverse transcription polymerase chain reaction (Real-time RT-PCR). The interactions between exosomes and human umbilical vein endothelial cells (HUVEC) were observed with confocal microscopy. Subconfluent HUVEC were harvested and treated with the indicated concentration of exosomes. Nude mice were injected subcutaneously with exosomes or PBS as control to verify the ability of angiogenesis. The results showed that diameter range of exosomes was range from 40 to 160 nm. The isolated exosomes expressed the CD9. There was approximately linear relation between the secretion of exosomes and cell density. The exosomes suppressed the production of IFN-γ from PBMNC, and contained miRNA associated with immune regulation such as miR301, miR22 and miR-let-7a. Exosomes induced vascular tube formation in vitro and vascularization of Matrigel plugs in vivo. It is concluded that the BMMSC-derived exosomes can regulate immunity and support vascularization.
Adult ; Animals ; Bone Marrow Cells ; cytology ; metabolism ; Cells, Cultured ; Exosomes ; immunology ; metabolism ; Female ; Humans ; Interferon-gamma ; metabolism ; Leukocytes, Mononuclear ; cytology ; Male ; Mesenchymal Stromal Cells ; cytology ; metabolism ; Mice, Nude ; Middle Aged ; Neovascularization, Physiologic

OBJECTIVETo isolate exosomes from rabbit aqueous humor and to investigate their immunosuppression function.

METHODSAqueous humor was collected from 40 New Zealand rabbits and exosomes were isolated by fractional separation and ultracentrifugation methods; the morphology was studied with electron microscopy. The immunosuppressive-related proteins of exosomes were detected with Western blotting; their inhibitory effect on ConA-induced proliferation of T lymphocyte was estimation with CCK-8 cells proliferation assay.

RESULTSEight milliliters of aqueous humor were collected from 40 New Zealand rabbits and 200 μg exosomes was yielded. Under electron microscope, the exosomes had typical structure of lipid bi-layer with a diameter of 50-100 nm. The results of Western blotting showed that these exosomes expressed Hsp70, CD9 and Alix but not Grp94, presenting a typical exosomes protein profile. Moreover, exosomes expressed high level of TGF-β and significantly inhibited the proliferation of T lymphocytes.

CONCLUSIONImmunosuppressive exosomes can be isolated from rabbit aqueous humor, which may be involved in immunotolerance of the eye.

Animals ; Aqueous Humor ; immunology ; Cells, Cultured ; Exosomes ; immunology ; metabolism ; ultrastructure ; Female ; Immune Tolerance ; Male ; Rabbits ; T-Lymphocytes ; immunology

OBJECTIVETo investigate the effects of the histone deacetylase inhibitor, MS-275, on the immune molecule content and categories in hepatocarcinoma exosomes.

METHODSExosomes were isolated from the human hepatocarcinoma cell lines, HepG2 and Hep3b, and purified by a combination technique of ultrafiltration centrifugation and sucrose gradient ultracentrifugation. The expressions of heat shock protein (HSP)70, human leukocyte antigen (HLA)-I, HLA-DR, cluster of differentiation (CD) 80 and NY-ESO-1 on exosomes were analyzed with immunoelectron microscopy and Western blotting before and after MS-275 treatment. Intergroup differences were statistically analyzed by the Student's paired t-test.

RESULTSMS-275 treatment of both HepG2 and Hep3b cell types significantly increased the numbers of exosomes, their total protein content, and expression of HSP70, HLA-I and CD80 (per 100 exosomes), as compared to non-treated cells (all, P less than 0.01). MS-275 was also found to induce de novo expression of HLA-DR, but had no significant effect on NY-ESO-1 expression (P more than 0.05). The findings from immunoelectron microscopy confirmed those from Western blotting.

CONCLUSIONThe histone deacetylase inhibitor, MS-275, can significantly alter the immune molecule content and categories in exosomes of hepatocarcinoma cells. The differential expression profile may reflect an anti-cancer immune response and represent molecular targets for novel anti-hepatoma therapeutic or preventative strategies.

Antigens, Neoplasm ; immunology ; metabolism ; Benzamides ; pharmacology ; Carcinoma, Hepatocellular ; immunology ; metabolism ; Exosomes ; immunology ; metabolism ; Hep G2 Cells ; Histocompatibility Antigens Class I ; immunology ; metabolism ; Histone Deacetylase Inhibitors ; pharmacology ; Humans ; Pyridines ; pharmacology

OBJECTIVETo prepare IL-2-anchored and tumor-derived exosomes vaccine, and investigate the antitumor efficiency of the special cytotoxic T-lymphocytes induced by Ex/GPI-IL-2.

METHODSTo construct pEGFP-N1-IL2gpi plasmid coding a fusion gene of a DNA oligo encoding GPI-anchor signal sequence attaching to human IL-2 cDNA. Then T24 cell lines stably expressing GPI-IL-2 proteins (T24/GPI-IL-2) were established. Ex/GPI-IL-2 were isolated and purified by ultrafiltration and sucrose gradient centrifugation, and the morphology and molecule markers were analyzed. The mixed lymphocyte reaction study and cytotoxic study were performed to determine the proliferative effect of T lymphocytes and the cytotoxicity induced by Ex/GPI-IL-2.

RESULTSThe pEGFP-N1-IL2gpi plasmid was successfully constructed, and cell lines stably expressing GPI-IL-2 fusion proteins were established. Ex/GPI-IL-2 were small vesicular and saucer-shaped in diameter of 30-90 nm, containing heat shock protein 70, intercellular adhesion molecule-1, MAGE-1 and GPI-IL-2. Ex/GPI-IL-2-pulsed could dendritic cells induce proliferation of T cells and cytotoxic immune response more efficiently (P<0.05).

CONCLUSIONSGPI-IL-2 gene-modified tumor cells can make the exosomes containing GPI-IL-2 with an increased anti-tumor effect. Our study provides a feasible approach for exosome-based tumor immunotherapy of bladder transitional cell tumors.

Cancer Vaccines ; immunology ; Carcinoma, Transitional Cell ; immunology ; metabolism ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Exosomes ; genetics ; metabolism ; Glycosylphosphatidylinositols ; metabolism ; HSP70 Heat-Shock Proteins ; metabolism ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; Interleukin-2 ; metabolism ; Melanoma-Specific Antigens ; metabolism ; Plasmids ; Recombinant Fusion Proteins ; metabolism ; T-Lymphocytes, Cytotoxic ; immunology ; Transfection ; Urinary Bladder Neoplasms ; immunology ; metabolism ; pathology

Exosomes are small membrane vesicles secreted from various types of cells. Tumor-derived exosomes contain MHC class I molecules and tumor-specific antigens, receiving attention as a potential cancer vaccine. For induction of efficient anti-tumor immunity, CD4+ helper T cells are required, which recognize appropriate MHC class II-peptide complexes. In this study, we have established an MHC class II molecule-expressing B16F1 murine melanoma cell line (B16F1-CIITA) by transduction of the CIITA (Class II transactivator) gene. Exosomes from B16-CII cells (CIITA-Exo) contained a high amount of MHC class II as well as a tumor antigen TRP2. When loaded on dendritic cells (DCs), CIITA-Exo induced the increased expression of MHC class II molecules and CD86 than the exosomes from the parental cells (Exo). In vitro assays using co-culture of immunized splenocytes and exosome-loaded DCs demonstrated that CIITA-Exo enhanced the splenocyte proliferation and IL-2 secretion. Consistently, compared to B16-Exo, CIITA-Exo induced the increased mRNA levels of inflammatory cytokines such as TNF-alpha, chemokine receptor CCR7 and the production of Th1-polarizing cytokine IL-12. A tumor preventive model showed that CIITA-Exo significantly inhibited tumor growth in a dose-dependent manner. Ex vivo assays using immunized mice demonstrated that CIITA-Exo induced a higher amount of Th1-polarized immune responses such as Th1-type IgG2a antibodies and IFN-gamma cytokine as well as TRP2-specific CD8+ T cells. A tumor therapeutic model delayed effects of tumor growth by CIITA-Exo. These findings indicate that CIITA-Exo are more efficient as compared to parental Exo to induce anti-tumor immune responses, suggesting a potential role of MHC class II-containing tumor exosomes as an efficient cancer vaccine.
Animals ; Cancer Vaccines/genetics/immunology ; Cell Line, Tumor ; Cell Proliferation ; Dendritic Cells/immunology ; Exosomes/genetics/*metabolism ; Gene Expression Regulation ; Gene Transfer Techniques ; Immunity, Cellular/immunology ; Immunity, Humoral/immunology ; Immunotherapy ; Lymphocyte Activation/immunology ; Melanoma, Experimental/mortality/pathology/*physiopathology ; Mice ; Mice, Inbred C57BL ; Nuclear Proteins/*genetics/*metabolism ; Survival Analysis ; T-Lymphocytes/immunology/metabolism ; Trans-Activators/*genetics/*metabolism ; Transduction, Genetic