Sera of patients suffering from inflammatory diseases contain group IIA but not group V phospholipase A(2).

During recent years, the high phospholipase A(2) (PLA(2)) concentrations at sites of inflammation and in circulation in several life-threatening diseases, such as sepsis, multi-organ dysfunction and acute respiratory distress syndrome, has generally been ascribed to the non-pancreatic group IIA PLA(2). Recently the family of secreted low molecular mass PLA(2) enzymes has rapidly expanded. In some cases, a newly described enzyme appeared to be cross-reactive with antibodies against the group IIA enzyme.

Regulation of the expression of group IIA and group V secretory phospholipases A(2) in rat mesangial cells.

Rat mesangial cells synthesize and secrete a secretory phospholipase A(2) upon stimulation of the cells with cytokines, like IL-1beta and TNF and with cAMP elevating agents like forskolin. This enzyme was previously characterized to belong to group IIA sPLA(2). The discovery of several other low molecular weight phospholipases, like group IIC in murine testis and group V in human and rat heart, prompted investigations on the presence of group IIC and group V sPLA(2) in rat mesangial cells.

Half-life of interleukin-1 beta-induced group II phospholipase A2 in rat mesangial cells.

Group II phospholipase A2 (sPLA2) has been implicated as an important agent involved in a number of inflammatory processes. Potent pro-inflammatory cytokines, such as interleukin-1 beta (IL-1 beta) and tumor necrosis factor (TNF) have been found to induce sPLA2 synthesis and release from many cell types among which mesangial cells. Although considerable research has been devoted to unravelling the mechanisms underlying the induction of sPLA2 not much is known about the time scale at which the cytokine elicited signals for sPLA2 induction persist in target cells.

Purification and characterization of Ca(2+)-dependent phospholipases A2 from rat kidney.

Three phospholipase A2 (PLA2) activities were identified in rat kidney. In the particulate fraction a PLA2 activity was present which was cross-reactive with polyclonal antibodies against the 14-kDa group II PLA2. This PLA2 was partially solubilized and purified to near homogeneity.

Catabolism of platelet-activating factor and its acyl analog. Differentiation of the activities of lysophospholipase and platelet-activating-factor acetylhydrolase.

Recent investigations have shown the presence of 1-acyl-2-acetyl-sn-glycero-3-phosphocholine, i.e. the acyl analog of platelet-activating factor (PAF), in unstimulated tissues as well as its formation along with platelet-activating factor upon stimulation of a variety of cells.