Amilorides inhibit SARS-CoV-2 replication in vitro by targeting RNA structures

Area of Science:

• Virology
• Medicinal Chemistry
• Structural Biology

Background:

• Understanding coronavirus (CoV) biology is crucial due to the SARS-CoV-2 pandemic and the threat of future pandemics.
• Small molecules can elucidate virus replication mechanisms and serve as antiviral drug leads.
• Previous work demonstrated amiloride scaffolds targeting viral RNA structures for therapeutic development.

Approach:

• Analyzed CoV RNA genomes for conserved, targetable structures in the 5'-untranslated region (UTR).
• Screened an amiloride-based library against human coronavirus OC43 to identify inhibitory compounds.
• Validated lead amilorides against replication-competent SARS-CoV-2 using viral plaque assays and cell culture supernatant analysis.

Key Points:

• Amilorides demonstrated significant inhibition of OC43 and SARS-CoV-2 replication.
• Reporter assays confirmed the importance of 5'-UTR RNA structures for small molecule efficacy.
• NMR studies pinpointed specific interactions between amilorides and bulge-like structures in CoV 5'-UTR stem loops (4, 5a, and 6).

Conclusions:

• Identified the first small molecules targeting specific RNA structures in the CoV 5'-UTR.
• These amilorides serve as chemical probes for studying CoV RNA biology.
• The findings pave the way for developing novel, RNA-targeted antiviral therapies against coronaviruses.