A New Transferrin Receptor Aptamer Inhibits New World Hemorrhagic Fever Mammarenavirus Entry

Abstract

Pathogenic New World hemorrhagic fever mammarenaviruses (NWM) utilize Glycoprotein 1 (GP1) to target the apical domain of the human transferrin receptor (hTfR) for facilitating cell entry. However, the conservation between their GP1s is low. Considering this and the slow evolutionary progression of mammals compared to viruses, therapeutic targeting of hTfR provides an attractive avenue for cross-strain inhibition and diminishing the likelihood of escape mutants. Aptamers present unique advantages for the development of inhibitors to vial entry, including ease of synthesis, lack of immunogenicity, and potentially cold-chain breaking solutions to diseases endemic to South America. Here, recognizing that in vivo competition with the natural ligand, transferrin (Tf), likely drove the evolution of GP1 to recognize the apical domain, we performed competitive in vitro selections against hTfR-expressing cells with supplemented Tf. The resultant minimized aptamer, Waz, binds the apical domain of the receptor and inhibits infection of human cells by recombinant NWM in culture (EC50 ~400 nmol/l). Aptamer multimerization further enhanced inhibition >10-fold (EC50 ~30 nmol/l). Together, our results highlight the ability to use a competitor to bias the outcome of a selection and demonstrate how avidity effects can be leveraged to enhance both aptamer binding and the potency of viral inhibition.

A replication-competent vesicular stomatitis virus for studies of SARS-CoV-2 spike-mediated cell entry and its inhibition

“…In contrast to the single-cycle pseudotypes, replication-competent recombinant VSVs (rVSVs) encoding the heterologous virus entry glycoprotein gene(s) in cis as their only entry protein(s) are easier to produce at high yields and also afford forward-genetic studies of viral entry. We and others have generated and used such rVSVs to safely and effectively study entry by lethal viruses that require high biocontainment (Caì et al, 2019;Jae et al, 2013;Jangra et al, 2018;Kleinfelter et al, 2015;Maier et al, 2016;Raaben et al, 2017;Whelan et al, 1995;Wong et al, 2010). Although rVSVs bearing the S glycoprotein from SARS-CoV (Fukushi et al, 2006a(Fukushi et al, , 2006bKapadia et al, 2005Kapadia et al, , 2008 and the Middle East respiratory syndrome coronavirus (MERS-CoV) (Liu et al, 2018) have been developed, no such systems have been described to date for SARS-CoV-2.…”

AptCompare: optimized de novo motif discovery of RNA aptamers via HTS-SELEX

“…We evaluated the performance of AptCompare using the data set from an aptamer selection against the human transferrin receptor (hTfR) previously conducted in our laboratory (Wilner et al, 2012;Maier et al, 2016). The original selection, which did not use HTS, identified three aptamers, all of which share a core motif, characterized by two asymmetric internal loops and a longer motif in one of the loops ( Supplementary Figure S1(a)).…”

A DNA aptamer efficiently inhibits the infectivity of Bovine herpesvirus 1 by blocking viral entry

“…Aptamers are able to form three-dimensional structures and their secondary structures influence their biological properties 30 . Stem-loop patterns in aptamers significantly influence binding affinities 31 .…”