Phosphatidylinositol inhibits respiratory syncytial virus infection

Area of Science:

• Pulmonary Medicine
• Virology
• Immunology

Background:

• Respiratory syncytial virus (RSV) causes widespread infections, particularly in young children and adults with lung disease.
• Anionic pulmonary surfactant lipids, like phosphatidylglycerol (PG), show antiviral properties against RSV.
• The antiviral potential of phosphatidylinositol (PI), another anionic pulmonary surfactant phospholipid, was unexplored.

Purpose of the Study:

• To investigate the antiviral activity of phosphatidylinositol (PI) against respiratory syncytial virus (RSV).
• To determine PI's mechanism of action, efficacy in vivo, and duration of action in the lungs.

Main Methods:

• In vitro studies using BEAS2B epithelial cells challenged with RSV.
• Assessment of interleukin-8 production and viral infection levels.
• In vivo studies involving intranasal inoculation of PI and RSV in mice.
• Evaluation of viral burden, inflammatory cell influx, and lung histopathology.

Main Results:

• PI liposomes completely suppressed interleukin-8 production in RSV-challenged cells.
• PI reduced RSV infection in vitro by over 1000-fold by preventing viral attachment.
• Intranasal PI in mice reduced viral burden 30-fold, decreased inflammation, and improved lung tissue.
• PI demonstrated a residence time of over 6 hours in the mouse lung and an 85% reduction in viral burden when administered 2 hours prior to infection.

Conclusions:

• Phosphatidylinositol (PI) possesses potent antiviral properties against RSV.
• PI acts as an effective innate immune mediator in the lung with a significant prophylactic window.
• PI and PG have complementary roles in the lung's intrinsic antiviral defense mechanisms.