SELEX-discovered aptamer that inhibits cellular interleukin-17/interleukin-17 receptor interaction and antagonizes interleukin-17 signaling.

This research is based on a Systematic Evolution of Ligands by EXponential enrichment, also referred to as in vitro selection against the extracellular domain of human interleukin-17 receptor A (IL-17RA). Pull-down assay via quantitative polymerase chain reaction and chemiluminescence detection showed that the cloned RNA with the enriched sequence bound to human IL-17RA and inhibited the interaction between IL-17RA and human interleukin-17A (IL-17A). We also revealed that the newly discovered IL-17RA-binding RNA aptamer bound to cellular IL-17RA, inhibited the cellular IL-17RA/IL-17A interaction, and antagonized cellular IL-17A signaling.

Artificial aptamer that inhibits interleukin-23/interleukin-23 receptor interaction discovered via SELEX.

Interaction between the pro-inflammatory cytokine interleukin-23 (IL-23) and IL-23 receptor (IL-23R) is related to the development of inflammatory autoimmune diseases such as psoriasis, inflammatory bowel disease, and Crohn's disease. In this study, we conducted systematic evolution of ligands by exponential enrichment (SELEX) for in vitro selection against human IL-23 and observed RNA sequence enrichment in the final SELEX round. IL-23-pull-down assay by chemiluminescence detection and fluorescence imaging demonstrated that SELEX-enriched RNA clone bound to IL-23. Quantitative polymerase chain reaction-based pull-down assay using the IL-23 alpha (IL-23A) subunit, a component of the IL-23 heterodimer, indicated that the RNA clone bound to IL-23A, which is favorable for autoimmune disease treatment. We also observed that the novel IL-23-binding RNA aptamer inhibited interaction between IL-23 and IL-23R. Thus, the novel IL-23-binding RNA aptamer can be used for IL-23 studies and has potential to be used for IL-23 diagnosis and IL-23-related inflammatory autoimmune disease treatment.

In vitro display evolution of the PURE system-expressed TNFα-binding unnatural cyclic peptide containing an N-methyl-d-amino acid.

Tumor necrosis factor-alpha (TNFα) is a multifunctional cytokine associated with inflammation, immune responses, and autoimmune diseases including rheumatoid arthritis, inflammatory bowel disease, and psoriasis. In the present study, we performed in vitro selection, systematic evolution of ligands by exponential enrichment (SELEX) against human TNFα from mRNA-displayed peptide library prepared with Escherichia coli-reconstituted cell-free transcription/translation system (PURE system) and cyclized by N-chloroacetyl-N-methyl-d-phenylalanine incorporated by genetic code expansion (sense suppression). We identified a novel TNFα-binding thioether-cyclized peptide that contains an N-methyl-d-phenylalanine. Since cyclic structure and presence of an N-methyl-d-amino acid can increase proteolytic stability, the TNFα binding peptide has potential to be used for therapeutic, research and diagnostic applications.

In vitro selection of an RNA aptamer yields an interleukin-6/interleukin-6 receptor interaction inhibitor.

Interleukin-6 (IL-6) binds to the IL-6 receptor (IL-6R) subunit, related to autoimmune diseases and cytokine storm in COVID-19. In this study, we performed systematic evolution of ligands by exponential enrichment and identified a novel RNA aptamer. This RNA aptamer not only bound to IL-6R with a dissociation constant of 200 n m, but also inhibited the interaction of IL-6R with IL-6.