in-vitro-synthesis-modified-mrna-for-induction-protein-expression

<em>In Vitro</em> Synthesis of Modified mRNA for Induction of Protein Expression in Human Cells

The exogenous delivery of coding synthetic messenger RNA (mRNA) for induction of protein synthesis in desired cells has enormous potential in the fields ...

University Hospital Tuebingen

Target specific short single-stranded DNA (ssDNA) molecules, called aptamers, are auspicious ligands for numerous in vivo applications. However, aptamers are synthetic molecules, which might be recognized by the immune cells in vivo and induce an activation of the innate immune system. Thus, immune activation potential of synthetic ssDNA oligonucleotides (ODNs) was determined using a well established closed-loop circulation model. Fresh human blood was incubated at 37°C for 2 or 4 hours with ssDNA ODNs (SB_ODN) or CpG ODN as positive control. Transcriptional changes were determined by microarray analyses. Blood samples containing SB_ODN demonstrated after 4 hours a significant regulation of 295 transcripts. Amongst others, CCL8, CXCL10, CCL7 and CXCL11 were highest regulated genes. Gene Ontology terms and KEGG pathway analyses exhibited that the differentially expressed genes belong to the transcripts that are regulated during an immune and inflammatory response, and were overrepresented in TLR signaling pathway. This study shows for the first time the potential of aptamers to activate immune system after systemic application into the human blood. Thus, we highly recommend performing of these preclinical tests with potential aptamer-based therapeutics.

Potential capacity of aptamers to trigger immune activation in human blood.

Aptamers are synthetic single-stranded DNA (ssDNA) molecules with the ability to fold into complex three-dimensional structures. They can bind their targets with a high selectivity and affinity, thus they have an enormous potential as therapeutic agents. However, since aptamers are synthetic and especially since certain sequences can increasingly bind to the pattern recognition receptors of the immune cells when applied in vivo, they can induce an immune activation. Here, we established a real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) based assay to evaluate aptamers-induced immune activation prior to in vivo studies. Human whole blood or plasmacytoid dendritic cell line (PMDC05) were incubated with CpG, R10-60 aptamer, start library, or a CpG containing aptamer. After 2 and 4 h, cytokine expression was measured using qRT-PCR to determine immune reaction against different aptamers. CpG containing a phosphorothioate backbone led to a significant up-regulation of CCL-7, IFN-1α, IFN-1β in whole blood after 4 h. Compared to the samples without ssDNA, significantly higher TNF-α expression was detected after the R10-60 aptamer incubation for 4 h. The stimulation of PMDC05 cells with different ssDNA enabled more sensitive detection of aptamer sequence specific immune activation. After 4 h, CpG led to a significantly higher expression of CCL-8, CXCL-10, IL-1β, IL-6, IL-8, IFN-1β, and TNF-α. R10-60 aptamer caused a significant up-regulation of IL-1β, IFN-1β, and TNF-α. Negative control aptamers did not induce an immune activation. The use of this assay before starting with in vivo studies will facilitate the in vitro prediction of immune activation potential of aptamers. Copyright © 2014 John Wiley & Sons, Ltd.

Article	Year
Potential capacity of aptamers to trigger immune activation in human blood. PloS one\| PubMed ID: 23935890	2013
In vitro test system for evaluation of immune activation potential of new single-stranded DNA-based therapeutics. Drug testing and analysis\| PubMed ID: 24817283	2014

Heidrun Steinle

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