The design and discovery of phospholipase A2 inhibitors for the treatment of inflammatory diseases

This review article summarizes the most important synthetic PLA2 inhibitors developed to target each one of the four major types of human PLA2 (cytosolic cPLA2, calcium-independent iPLA2, secreted sPLA2, and lipoprotein-associated Lp-PLA2), discussing their in vitro and in vivo activities as well as their recent applications and therapeutic properties. Recent findings on the role of PLA2 in the pathobiology of COVID-19 are also discussed.Although a number of PLA2 inhibitors have entered clinical trials, none has reached the market yet. Lipoprotein-associated PLA2 is now considered a biomarker of vascular inflammation rather than a therapeutic target for inhibitors like darapladib. Inhibitors of cytosolic PLA2 may find topical applications for diseases like atopic dermatitis and psoriasis. Inhibitors of secreted PLA2, varespladib and varespladib methyl, are under investigation for repositioning in snakebite envenoming. A deeper understanding of PLA2 enzymes is needed for the development of novel selective inhibitors. Lipidomic technologies combined with medicinal chemistry approaches may be useful tools toward this goal.