Phospholipase A2 in astrocytes: responses to oxidative stress, inflammation, and G protein-coupled receptor agonists.

Astrocytes comprise the major cell type in the central nervous system (CNS) and they are essential for support of neuronal functions by providing nutrients and regulating cell-to-cell communication. Astrocytes also are immune-like cells that become reactive in response to neuronal injury. Phospholipases A2 (PLA2) are a family of ubiquitous enzymes that degrade membrane phospholipids and produce lipid mediators for regulating cellular functions. Three major classes of PLA2 are expressed in astrocytes: group IV calcium-dependent cytosolic PLA2 (cPLA2), group VI calcium-independent PLA2 (iPLA2), and group II secretory PLA2(sPLA2). Upregulation of PLA2 in reactive astrocytes has been shown to occur in a number of neurodegenerative diseases, including stroke and Alzheimer's disease. This review focuses on describing the effects of oxidative stress, inflammation, and activation of G protein-coupled receptors on PLA2 activation, arachidonic acid (AA) release, and production of prostanoids in astrocytes.