A Short Dna Aptamer That Recognizes Tnf Alpha And Blocks Its Activity In Vitro

Tumor necrosis factor-alpha (TNF alpha) is a pivotal component of the cytokine network linked to inflammatory diseases. Protein-based, TNF alpha inhibitors have proven to be clinically valuable. Here, we report the identification of short, single-stranded DNA aptamers that bind specifically to human TNF alpha. One such 25-base long aptamer, termed VR11, was shown to inhibit TNF alpha signaling as measured using NF-kB luciferase reporter assays. This aptamer bound specifically to TNF alpha with a dissociation constant of 7.0 +/- 2.1 nM as measured by surface plasmon resonance (SPR) and showed no binding to TNF beta. Aptamer VR11 was also able to prevent TNF alpha-induced apoptosis as well as reduce nitric oxide (NO) production in cultured cells for up to 24 h. As well, VR11, which contains a GC rich region, did not raise an immune response when injected intraperitoneally into C57BL/6 mice when compared to a CpG oligodeoxynucleotide (ODN) control, a known TLR9 ligand. These studies suggest that VR11 may represent a simpler, synthetic scaffold than antibodies or protein domains upon which to derive nonimmunogenic oligonucleotide-based inhibitors of TNF alpha.