Objective To characterize the properties of Hepa1-6-derived microparticles (Hepa1-6-MPs), investigate their stimulatory effects on dendritic cells (DCs) and their cellular uptake pathways, and explore the specific cytotoxic effects of CD8⁺ T cells induced by Hepa1-6-MP-loaded DCs on hepatoma cell lines, with the aim of developing a novel immunotherapeutic model for hepatocellular carcinoma (HCC). Methods The isolated Hepa1-6-MPs were identified using Western blotting, transmission electron microscopy (TEM) and dynamic light scattering (DLS). Flow cytometry was used to assess the uptake pathways of Hepa1-6-MPs by DCs. Subsequently, enzyme-linked immunosorbent assay (ELISA) was used to measure the effects of Hepa1-6-MP-loaded DCs on the release levels of tumor necrosis factor α(TNF-α) and interferon γ(IFN-γ) into the supernatant of CD8⁺ T cells. Lactate dehydrogenase (LDH) tests were conducted to evaluate the cytotoxic effects of CD8⁺ T cells stimulated by Hepa1-6-MP-loaded DCs on hepatoma cells. Results The morphology, size and protein markers of Hepa1-6-MPs met the established criteria. Hepa1-6-MPs enhanced the expression of DC maturation markers CD80 and CD86, and were internalized by DCs via clathrin-mediated endocytosis and phagocytosis pathways. Subsequently, Hepa1-6-MP-loaded DCs stimulated CD8⁺ T cells to release high levels of TNF-α and IFN-γ, which induced their specific cytotoxicity against HCC cells. Conclusion These findings suggest that Hepa1-6-MP-loaded DCs may be a promising HCC immunotherapeutic tool.
Carcinoma, Hepatocellular/therapy* ; Liver Neoplasms/therapy* ; Dendritic Cells/immunology* ; Humans ; Cancer Vaccines/immunology* ; CD8-Positive T-Lymphocytes/immunology* ; Cell Line, Tumor ; Tumor Necrosis Factor-alpha/immunology* ; Interferon-gamma/immunology* ; Cell-Derived Microparticles/immunology* ; Animals

BACKGROUNDEndothelial cells derived microRNAs can be detected in plasma and serum and there is evidence that inflammatory disease states may affect the levels of circulating microRNAs. However, there is no direct proof that inflammation induces endothelial cells to release microRNAs into circulation. This study aimed to explore whether inflammation could induce endothelial cells to release microRNAs into circulation and to investigate whether these released microRNAs derived from endothelial cells were transported in microparticles.

METHODSMicroparticles were isolated from human atherosclerotic plaques with an active inflammatory phenotype and normal vascular tissue. Flow cytometry and real-time PCR were used to detect the levels of microparticles and microRNAs. Human umbilical vein endothelial cells (HUVEC) was treated with tumour necrosis factor a (TNF-α, 10 ng/ml) for 24 hours, and then HUVEC and the culture medium were respectively collected.

RESULTSBy comparing microparticles isolated from human atherosclerotic plaques with an active inflammatory phenotype (n = 9) and those from normal vascular tissues (n = 9), we found levels of annexin V(+) microparticles and annexin V(+) CD144(+) microparticles were significantly increased in plaques and angiogenesis associated microRNAs (106b, 25, 92a and 21) were also significantly increased in microparticles from plaques. After exposure to TNF-α at a concentration of 10 ng/ml (TNF-α group, n = 3) or DMEM (control group, n = 3) for 24 hours, counts of microparticles and expressions of microRNAs 106b, 25, 92a and 21 in microparticles isolated from medium significantly increased. However, there were no differences in the intracellular levels of microRNAs 25, 92a or 21 isolated from HUVEC between TNF-α group and control group, while microRNA 106b decreased in TNF-α group.

CONCLUSIONInflammation could induce endothelial cells to release angiogenesis associated microRNAs into circulation, causing higher levels of circulating endothelial cells derived microRNAs in atherosclerosis.

Annexin A5 ; metabolism ; Cell-Derived Microparticles ; metabolism ; Cells, Cultured ; Gene Expression Regulation ; drug effects ; Human Umbilical Vein Endothelial Cells ; drug effects ; metabolism ; Humans ; Inflammation ; genetics ; immunology ; MicroRNAs ; genetics ; metabolism ; Real-Time Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha ; pharmacology