The Role of Phospholipase A2 and Lipoxygenases Associated with Arachidonic Acid in Oxidative Stress-Induced Cell Injury

Yoshihiro      Higuchi

Abstract

Phospholipases A2 (PLA2) comprise a set of extracellular and intracellular enzymes that catalyze the hydrolysis of the sn-2 fatty acyl bond of phospholipids to yield fatty acids and lysophospholipids. The PLA2 reaction is the primary pathway through which arachidonic acid (AA) is released from phospholipids. PLA2s have an important role in cellular death that occurs via necrosis or apoptosis. Reactive oxygen species are known to contribute to tissue damage during injury and inflammation. However, the species can also be sensed by the cells and trigger intracellular signaling cascades during cell death. This review examines recent evidence on the involvement of reactive oxygen species in lipid signaling during apoptosis and necrosis. Attention is focused on activation of PLA2s and lipoxygenases, which play important roles in mediating AA release and metabolism. The participation of several types of PLA2s in AA mobilization from phospholipids is discussed. The involvement of alternative routes for AA mobilization under oxidative stress is also considered.

Keywords: phospholipids, membrane permeability, prostaglandins, LOX expression, Reactive oxygen species

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