G-quadruplex-forming small RNA inhibits coronavirus and influenza A virus replication

Area of Science:

• Virology
• RNA Therapeutics
• Antiviral Drug Development

Background:

• Future pandemic threats are posed by novel coronaviruses and influenza A viruses.
• Existing antiviral strategies often target viral genome G-quadruplexes.
• A need exists for novel antiviral agents with improved delivery and efficacy.

Purpose of the Study:

• To investigate the antiviral potential of 12mer guanine RNA (G12) and its derivatives (G12(S)) against coronaviruses and influenza A viruses.
• To elucidate the mechanism of action of G12(S) in inhibiting viral replication.
• To assess the therapeutic efficacy and safety of G12(S) in preclinical models.

Main Methods:

• Direct addition of G12 and G12(S) to cell cultures infected with human coronaviruses and influenza A viruses.
• Measurement of viral infectivity and assessment of cellular toxicity and innate immune responses.
• Administration of G12(S) to mice infected with coronavirus to evaluate weight loss alleviation.
• Analysis of G12(S) structure and its interaction with viral components.

Main Results:

• G12 and G12(S) rapidly entered the cytoplasm and significantly suppressed viral propagation (1/100 to 1/1000 of normal infectivity).
• No cellular toxicity or induction of innate immunity was observed.
• G12(S) treatment alleviated weight loss in mice infected with coronavirus.
• G12(S) likely functions by forming G-quadruplex structures that impede viral RNA-nucleoprotein interactions.

Conclusions:

• Exogenous G-quadruplex-forming small RNA, such as G12(S), can effectively inhibit viral replication by displacing genomic RNA from ribonucleoprotein complexes.
• This novel approach offers a versatile strategy for developing middle-molecule antivirals.
• The lipid nanoparticle-free delivery potential of G12(S) makes it a promising candidate for future antiviral therapies.