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

Abstract

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.