Is there an interplay between the SARS-CoV-2 spike protein and Platelet-Activating factor?

Area of Science:

• Immunology
• Hematology
• Virology

Background:

• COVID-19 significantly affects platelet function.
• The SARS-CoV-2 Spike protein enhances platelet aggregation.

Purpose of the Study:

• Evaluate mRNA vaccination effects on human platelet-rich plasma (hPRP) aggregation.
• Assess Spike protein modulation of platelet-activating factor (PAF)-induced aggregation.
• Investigate Spike protein's effect on PAF production in U-937 cells.

Main Methods:

• Ex vivo analysis of hPRP aggregation response to PAF, ADP, and collagen in vaccinated individuals.
• In vitro studies using recombinant Spike protein on hPRP and washed rabbit platelets (WRP).
• Measurement of intracellular PAF production and biosynthetic enzyme activity in U-937 cells.

Main Results:

• Vaccinated individuals' PRP showed lower EC50 values for PAF, ADP, and collagen.
• Spike protein augmented PAF-induced aggregation in non-vaccinated hPRP and WRP.
• Spike protein reduced collagen-induced aggregation and altered PAF-induced aggregation in vaccinated PRP.
• Spike protein stimulation increased PAF production and biosynthetic enzyme activity in U-937 cells.

Conclusions:

• The SARS-CoV-2 Spike protein modulates PAF production and activity.
• PAF inhibitors may be a therapeutic consideration for mild COVID-19 cases.