Antibacterial actions of secreted phospholipases A2. Review

Antibacterial properties of secreted phospholipases A2 (PLA2) have emerged gradually. Group (G) IIA PLA2 is the most potent among mammalian secreted (s) PLA2s against Gram-positive bacteria, but additional antibacterial compounds, e.g. the bactericidal/permeability-increasing protein, are needed to kill Gram-negative bacteria. The mechanisms of binding to the bacterial surface and the killing of bacteria by sPLA2s are based on the positive charge of the PLA2 protein and its phospholipolytic enzymatic activity, respectively. The concentration of GIIA PLA2 is highly elevated in serum of patients with bacterial sepsis, and overexpression of GIIA PLA2 protects transgenic mice against experimental Gram-positive infection. The synthesis and secretion of GIIA PLA2 are stimulated by the cytokines TNF-α, IL-1 and IL-6. Secreted PLA2s may be potentially useful new endogenous antibiotics to combat infections including those caused by antibiotic-resistant bacteria such as methicillin-resistant staphylococci and vancomysin-resistant enterococci.