No abstract

Objective As an extracellular vesicle, exosomes can release from virus‐infected cells containing various viral or host cellular elements and could stimulate recipient's cellular response. Enterovirus 71 (EV71), a single‐strand positive‐sense RNA virus, is known to cause hand, foot, and mouth disease (HFMD) in children and bring about severe clinical diseases. Methods Separated the human oral epithelial cells (OE cells) from normal buccal mucosa through enzyme digestion. Performed a comprehensive miRNA profiling in exosomes from EV71‐infected OE cells through deep small RNA‐seq. Using the Human Antiviral Response RT Profiler PCR Array profiles to explore the interactions of innate immune signaling networks with exosomal miR‐30a. Knocked out the MyD88 gene in macrophages using CRISPR/Cas9‐mediated genome editing method. Results Our study demonstrated that the miR‐30a was preferentially enriched in exosomes that released from EV71‐infected human oral epithelial cells through small RNA‐seq. We found that the transfer of exosomal miR‐30a to macrophages could suppress type Ⅰ interferon response through targeting myeloid differentiation factor 88 (MyD88) and subsequently facilitate the viral replication. Conclusions Exosomes released from EV71‐infected OE cells selectively packaged high level of miR‐30a that can be functionally transferred to the recipient macrophages resulted in targeting MyD88 and subsequently inhibited type I interferon production in receipt cells, thus promoting the EV71 replication.

Effective suicide gene delivery and expression are crucial to achieving successful effects in gene therapy. An ideal tumor-specific promoter expresses therapeutic genes in tumor cells with minimal normal tissue expression. We compared the activity of the FOS (FBJ murine osteosarcoma viral oncogene homolog) promoter with five alternative tumor-specific promoters in glioma cells and non-malignant astrocytes. The FOS promoter caused significantly higher transcriptional activity in glioma cell lines than all alternative promoters with the exception of CMV. The FOS promoter showed 13.9%, 32.4%, and 70.8% of the transcriptional activity of CMV in three glioma cell lines (U87, U251, and U373). Importantly, however, the FOS promoter showed only 1.6% of the transcriptional activity of CMV in normal astrocytes. We also tested the biologic activity of recombinant adenovirus containing the suicide gene herpes simplex virus thymidine kinase (HSV-tk) driven by the FOS promoter, including selective killing efficacy in vitro and tumor inhibition rate in vivo. Adenoviral-mediated delivery of the HSV-tk gene controlled by the FOS promoter conferred a cytotoxic effect on human glioma cells in vitro and in vivo. This study suggests that use of the FOS-tk adenovirus system is a promising strategy for glioma-specific gene therapy but still much left for improvement.

This abstract was not presented at the symposium.