Genistein Targets STING-Driven Antiviral Responses

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• Cytoplasmic DNA sensing by cyclic GMP-AMP (cGAMP) synthase (cGAS) activates the stimulator of interferon (IFN) genes (STING) pathway, crucial for antiviral immunity.
• Intercellular transfer of cGAMP via gap junctions propagates STING-mediated antiviral responses to adjacent cells.

Purpose of the Study:

• To investigate the effect of Genistein, a soy-derived flavonoid, on the cGAS-STING antiviral signaling pathway.
• To elucidate the mechanisms by which Genistein modulates STING activation and intercellular communication.

Main Methods:

• Genistein pretreatment of cells to assess its impact on gap-junction intercellular communication.
• Inhibition assays using a murine agonist (DMXAA) to evaluate direct effects on STING activation.
• Western blotting to analyze the interaction between STING, TBK1, and IKKε.
• Assessment of antiviral activity against Semliki Forest Virus infection.

Main Results:

• Genistein inhibited gap-junction intercellular communication, reducing STING signaling in adjacent cells.
• Genistein directly blocked STING activation by decreasing STING's interaction with TBK1 and IKKε.
• Genistein attenuated STING signaling in human and mouse cells, dampening antiviral activity against Semliki Forest Virus.

Conclusions:

• Genistein exhibits a proviral activity by inhibiting the cGAS-STING pathway at two key levels: cGAMP transfer and STING sensing.
• The findings suggest caution in using Genistein as an antiviral, as it may counteract host-protective STING activation.