RT Journal Article SR Electronic T1 Expression of members of the phospholipase A2 family of enzymes in human nasal mucosa JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 130 OP 138 DO 10.1183/09031936.01.00054701 VO 18 IS 1 A1 J. Lindbom A1 A.G. Ljungman A1 M. Lindahl A1 C. Tagesson YR 2001 UL http://erj.ersjournals.com/content/18/1/130.abstract AB Phospholipase A2 (PLA2) is a family of enzymes thought to play a key role in inflammation by releasing arachidonic acid for the synthesis of eicosanoids and lysophospholipid for the synthesis of platelet-activating factor. However, the precise contribution of different PLA2 types to the formation of inflammatory lipid mediators in the upper airways is not known and the expression of different PLA2 genes in the human nasal mucosa has not been examined.This study therefore investigated the occurrence of messenger ribonucleic acids (mRNAs) for different PLA2 forms (IB, IIA, IID, IIE, III, IVA, IVB, IVC, V, VI, VII, X, acid calcium-independent (aiPLA2), and calcium-independent membrane bound PLA2, (iPLA2-2)) in the nasal mucosa of five healthy human subjects.Using reversed transcription-polymerase chain reaction (RT-PCR) techniques it was found that all these PLA2 types except PLA2 V were expressed in all subjects, whereas PLA2 V was detected in only one individual on one single occasion. The relative abundance of the different PLA2 transcripts were aiPLA2>X≈IVA>IIA≈IIE≈IVB≈VI>IB≈IID≈III≈IVC≈VII≈iPLA2-2. To further quantify the mRNA-expression of PLA2 X, IVA and IIA, the samples were reanalysed with a quantitative PCR-technique utilizing competitive deoxyribonucleic acid (DNA) mimics as references. The amounts of PLA2 X, IVA and IIA mRNA were then estimated to 0.9±0.2, 1.1±0.7, and 0.0025±0.0021 amol (mean±se), respectively, confirming the relative abundance of these PLA2 transcripts and indicating that the recently described PLA2 X form is relatively strongly expressed.These findings demonstrate that a large number of PLA2 types are expressed in the normal human nasal mucosa. Moreover, this investigation demonstrates, for the first time, the presence of the newly discovered phospholipase A2 forms IID, IIE, III, IVB, IVC, X and calcium-independent membrane bound phospholipase A2 in the human nasal mucosa and raises the possibility that one or several of these may be involved in inflammatory reactions in the nose.This work was supported by the Swedish Medical Research Council (K99-27X-05983-19A), the Swedish Council for Work Life Research (96-0615) and the Vårdal Foundation, Sweden (96/48 A96 027).