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

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.

Aptamer-based Emerging Tools for Viral Biomarker Detection: A Focus on SARS-CoV-2

Viral infections can cause fatal illnesses to humans as well as animals. Early detection of viruses is therefore crucial to provide effective treatment to patients. Recently, the Covid-19 pandemic has undoubtedly given an alarming call to develop rapid and sensitive detection platforms. The viral diagnostic tools need to be fast, affordable, and easy to operate with high sensitivity and specificity equivalent or superior to the currently used diagnostic methods. The present detection methods include direct detection of viral antigens or measuring the response of antibodies to viral infections. However, the sensitivity and quantification of the virus are still a significant challenge. Detection tools employing synthetic binding molecules like aptamers may provide several advantages over the conventional methods that use antibodies in the assay format. Aptamers are highly stable and tailorable molecules and are therefore ideal for detection and chemical sensing applications. This review article discusses various advances made in aptamer-based viral detection platforms, including electrochemical, optical, and colorimetric methods to detect viruses, specifically SARS-Cov-2. Considering the several advantages, aptamers could be game-changing in designing high-throughput biosensors for viruses and other biomedical applications in the future.

In vitro selection of a single-strand DNA aptamer targeting the receptor-binding domain of SARS-CoV-2 spike protein

Nucleic acid aptamers are developed from a pool of random oligonucleotide libraries with an in vitro selection through systematic evolution of ligands via exponential enrichment (SELEX) process, which are capable of specific and high-affinity molecular binding against targets. The receptor-binding domain (RBD) of spike protein from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is involved in the early stages of viral infection, is a promising target for aptamer selection. Currently, there are no effective approaches to prevent virus from spreading. In this study, a new ssDNA aptamer RBD/S-A1 binding to the RBD of spike protein from SARS-CoV-2 with high affinity (K_d=1.74 ± 0.2 nM) and low cross-binding activity was selected and evaluated. Although aptamers targeting the RBD of spike protein from SARS-CoV-2 have been described in a handful of previous studies, the RBD/S-A1 aptamer identified in this work may be considered as a potential supplementation for the current diagnosis and research of coronavirus SARS-CoV-2.

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.

Aptamers in Virology-A Consolidated Review of the Most Recent Advancements in Diagnosis and Therapy

The use of short oligonucleotide or peptide molecules as target-specific aptamers has recently garnered substantial attention in the field of the detection and treatment of viral infections. Based on their high affinity and high specificity to desired targets, their use is on the rise to replace antibodies for the detection of viruses and viral antigens. Furthermore, aptamers inhibit intracellular viral transcription and translation, in addition to restricting viral entry into host cells. This has opened up a plethora of new targets for the research and development of novel vaccines against viruses. Here, we discuss the advances made in aptamer technology for viral diagnosis and therapy in the past decade.

A human epidermal growth factor receptor 3/heregulin interaction inhibitor aptamer discovered using SELEX

The interaction of human epidermal growth factor receptor 3 (HER3) and heregulin (HRG) is involved in resistance to human epidermal growth factor receptor 2 (HER2)-targeted cancer treatment, such as therapies using anti-HER2 monoclonal antibody. Therefore, inhibition of the HER3/HRG interaction is potentially valuable therapeutic target for cancer treatment. In this study, we used in vitro selection, also known as systematic evolution of ligands by exponential enrichment (SELEX) against the extracellular domain of human HER3, and discovered a novel RNA aptamer. Pull-down and bio-layer interferometry assays showed that RNA aptamer discovered specifically bound to HER3 with a dissociation constant (K_D) of 700 nM. Pull-down assays using chemiluminescence detection also revealed that the HER3-binding RNA aptamer inhibited interactions between HER3 and human HRG. These results indicated that the novel HER3-binding RNA aptamer has potential to be used as basic tool in a range of applications involving HER3/HRG interactions, including research, therapeutic, and diagnostic applications.