Metallo-supramolecular complexes enantioselectively target monkeypox virus RNA G-quadruplex and bolster immune responses against MPXV

Abstract

Abstract Mpox viruses (MPXV) has emerged as a formidable orthopoxvirus, posing an immense challenge to global public health. Understanding the regulatory mechanisms of MPXV infection, replication and immune evasion will benefit the development of novel antiviral strategies. Despite the involvement of G-quadruplexes (G4s) in modulating infection and replication processes of multiple viruses, their roles in MPXV life cycle remain largely unknown. Here, we found a highly conservative and stable G4 in MPXV, which acts as a positive regulatory element for viral immunodominant protein expression. Furthermore, by screening 42 optically pure chiral metal complexes, we identified the Λ enantiomer of a pair of chiral helical compounds can selectively target mRNA G4 and enhance expression of the 39-kDa core protein encoded by the MPXV A5L gene. Mechanistically, RNA G4-specific helicase DHX36 inhibits A5L protein expression by unwinding G4. In contrast, MH3 Λ enhanced mRNA stability by specifically targeting G4 structures and subsequently increased protein expression. Furthermore, given the pivotal role of the 39-kDa core protein in activating immune responses and facilitating virion maturation, modulation of MPXV G4 folding by MH3 Λ exhibited inhibitory effects on MPXV replication through enhancing immune response. Our findings underscore the critical involvement of G4 in MPXV life cycle and offer potential avenues for developing antiviral drugs targeting G4.