H₂O₂ renders cells accessible to lysis by exogenous phospholipase A₂: A novel mechanism for cell damage in inflammatory processes

Phospholipase A₂ (PLA₂) and H₂O₂, secreted from activated inflammatory cells, play a central role in the tissue damage occurring in inflammatory processes. However, while exogenous PLA₂ alone does not cause cell lysis, it readily does so when acting with H₂O₂. We have found that H₂O₂ degrades cell surface proteoglycans, thus rendering the membrane PL accessible to hydrolysis by exogenous PLA₂. This novel mechanism introduces a role for cell surface proteoglycans in protection of cells from damage by pro-inflammatory agents, and may assign a central role for the combined action of H₂O₂ and PLA₂ in inflammatory and bacteriocidal processes.