Antisense inhibition of oncogenic or other disease-related miRNAs and miRNA families in vivo may provide novel therapeutic strategies. However, this approach relies on the development of potent miRNA inhibitors and their efficient delivery into cells. Here, we introduce short seed-directed LNA oligonucleotides (12- or 14-mer antiseeds) with a phosphodiester backbone (PO) for efficient miRNA inhibition. We have analyzed such LNA (PO) antiseeds using a let-7a-controlled luciferase reporter assay and identified them as active miRNA inhibitors in vitro. Moreover, LNA (PO) 14-mer antiseeds against ongogenic miR-17-5p and miR-20a derepress endogenous p21 expression more persistently than corresponding miRNA hairpin inhibitors, which are often used to inhibit miRNA function. Further analysis of the antiseed-mediated derepression of p21 in luciferase reporter constructs - containing the 3'-UTR of p21 and harboring two binding sites for miRNAs of the miR-106b family - provided evidence that the LNA antiseeds inhibit miRNA families while hairpin inhibitors act in a miRNA-specific manner. The derepression caused by LNA antiseeds is specific, as demonstrated via seed mutagenesis of the miR-106b target sites. Importantly, we show functional delivery of LNA (PO) 14-mer antiseeds into cells upon complexation with polyethylenimine (PEI F25-LMW), which leads to the formation of polymeric nanoparticles. In contrast, attempts to deliver a functional seed-directed tiny LNA 8-mer with a phosphorothioate backbone (PS) by formulation with PEI F25-LMW remained unsuccessful. In conclusion, LNA (PO) 14-mer antiseeds are attractive miRNA inhibitors, and their PEI-based delivery may represent a promising new strategy for therapeutic applications.
Bacteria adhesion on implant surfaces is the major reason for local and systemic infections after implantation. In order to establish an anti-adhesion material, we constructed self-assembly nanostructured surfaces by wetting of poly(lactic-co-glycolic acid) (PLGA) films in ethyl acetate followed by a next step of dewetting under wet conditions. The resulting films had nanostructured surfaces with pores at nanoscale range between 200 and 500 nm. E. coli adhesion was examined on both flat spin coated and nanostructured PLGA films. The observations revealed that the bacterial adhesion onto the nanostructured surfaces was reduced in compared to the flat surfaces. Pore sizes affected the bacteria adhesion significantly. Due to its high biocompatibility and effectiveness against bacterial adhesion, these surfaces are ideal for biomedical device coatings.
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