Self-assembling short immunostimulatory duplex RNAs with broad spectrum antiviral activity

Abstract

The current COVID-19 pandemic highlights the need for broad-spectrum antiviral therapeutics. Here we describe a new class of self-assembling immunostimulatory short duplex RNAs that potently induce production of type I and type III interferon (IFN-I and IFN-III), in a wide range of human cell types. These RNAs require a minimum of 20 base pairs, lack any sequence or structural characteristics of known immunostimulatory RNAs, and instead require a unique conserved sequence motif (sense strand: 5’-C, antisense strand: 3’-GGG) that mediates end-to-end dimer self-assembly of these RNAs by Hoogsteen G-G base-pairing. The presence of terminal hydroxyl or monophosphate groups, blunt or overhanging ends, or terminal RNA or DNA bases did not affect their ability to induce IFN. Unlike previously described immunostimulatory siRNAs, their activity is independent of TLR7/8, but requires the RIG-I/IRF3 pathway that induces a more restricted antiviral response with a lower proinflammatory signature compared with poly(I:C). Immune stimulation mediated by these duplex RNAs results in broad spectrum inhibition of infections by many respiratory viruses with pandemic potential, including SARS-CoV-2, SARS-CoV, MERS-CoV, and influenza A, as well as the common cold virus HCoV-NL63 in both cell lines and human Lung Chips that mimic organ-level lung pathophysiology. These short dsRNAs can be manufactured easily, and thus potentially could be harnessed to produce broad-spectrum antiviral therapeutics at low cost.

Human organs-on-chips for disease modelling, drug development and personalized medicine

“…These results were included in a recent submission of a pre-IND (Investigational New Drug) meeting application to the FDA to request initiation of clinical trials to test whether azeliragon can suppress the cytokine storm in patients with COVID-19. Use of lung alveolus and airway chips also led to the discovery of a new class of broad-spectrum RNA therapeutics that induce a potent type I interferon response and inhibit infection by SARS-CoV2, SARS-CoV, MERS-CoV, HCoV-NL63 (a common cold virus) and multiple influenza A virus strains 60 .…”

Revolutionizing drug development: harnessing the potential of organ-on-chip technology for disease modeling and drug discovery

“…The platform was designed to replicate the human lung airway, with a flow rate of 60 μL/h in both endothelial and epithelial channels. These findings suggest that the organ-on-chip platform can be a powerful tool for studying the molecular mechanisms of immune response to viral infections in human lung epithelial cells ( Si et al, 2021b ). Overall, lung-on-chip technology holds great promise for improving our understanding of lung function and disease, and for developing more effective treatments for lung-related illnesses.…”