The guideline of the design and validation of MiRNA mimics

Phenotypic MicroRNA Microarrays

Microarray technology has become a very popular approach in cases where multiple experiments need to be conducted repeatedly or done with a variety of samples. In our lab, we are applying our high density spots microarray approach to microscopy visualization of the effects of transiently introduced siRNA or cDNA on cellular morphology or phenotype. In this publication, we are discussing the possibility of using this micro-scale high throughput process to study the role of microRNAs in the biology of selected cellular models. After reverse-transfection of microRNAs and siRNA, the cellular phenotype generated by microRNAs regulated NF-κB expression comparably to the siRNA. The ability to print microRNA molecules for reverse transfection into cells is opening up the wide horizon for the phenotypic high content screening of microRNA libraries using cellular disease models.

New role of microRNA: carcinogenesis and clinical application in cancer

MicroRNA (miRNA) is a cluster of small non-encoding RNA molecules of 21-23 nucleotides in length, which controls the expression of target gene at the post-transcriptional level. Recent researches have indicated that miRNA plays an essential role in carcinogenesis, such as affecting the cell growth, differentiation, apoptosis, and cell cycle. Nowadays, multiple promising roles of miRNA involved in carcinogenesis are emerging, and it is shown that miRNA closely relates to the process of epithelial-mesenchymal transition (EMT), the regulation of cancer stem cells (CSCs), the development of tumor invasion and migration. miRNA also acts as a biomarker stably expressed in serum and provides new target for molecular target therapy of various cancers. The aim of this review is to illustrate the new role of miRNA in carcinogenesis and highlight the new prospects of miRNA in cancer clinical application, such as in serological diagnosis and molecular-targeted therapeutics.

Ectopic expression of microRNA-155 enhances innate antiviral immunity against HBV infection in human hepatoma cells

Background

Host innate antiviral immunity is the first line of defense against viral infection, and is precisely regulated by thousands of genes at various stages, including microRNAs. MicroRNA-155 (miR-155) was found to be up-regualted during viral infection, and influence the host immune response. Besides, the expression of miR-155, or its functional orthologs, may also contribute to viral oncogenesis. HBV is known to cause hepatocellular carcinoma, and there is evidence that attenuated intracellular immune response is the main reason for HBV latency. Thus, we assume miR-155 may affect the immune response during HBV infection in human hepatoma cells.

Results

We found that ectopic expression of miR-155 upregulated the expression of several IFN-inducible antiviral genes in human hepatoma cells. And over-expression of miR-155 suppressed suppressor of cytokine signaling 1 (SOCS1) expression and subsequently enhanced signal transducers and activators of transcription1 (STAT1) and signal transducers and activators of transcription3 (STAT3) phosphorylation. We further demonstrate that ectopic expression of miR-155 inhibits HBV X gene expression to some extent in vitro.

Conclusion

MiR-155 enhances innate antiviral immunity through promoting JAK/STAT signaling pathway by targeting SOCS1, and mildly inhibits HBV infection in human hepatoma cells.