Distribution of the phospholipase A 2 receptor messenger RNA in human gestational tissues

Abstract

Recently, a model has been proposed for the involvement of secretory phospholipase A 2 (sPLA 2) the onset of and/or progression of human labour via the metabolism of cell membrane glycerophospholipids to generate biologically active, phospholipid-derived mediators. The recent molecular cloning and characterization of a cell-surface receptor for sPLA 2) raise the possibility that sPLA 2 enzymes may also affect cell function in intrauterine tissues via a receptor-mediated pathway. The aim of this study was to determine the expression profile of the PLA 2 receptor messenger RNA in human gestational tissues at term. Messenger RNA for the PLA 2 receptor was detected in amnion, choriodecidua and placenta by RT-PCR and transcripts of similar size to the 6.5- and 5.4-kb transcripts previously reported in various other human tissues were detected in choriodecidua by Northern blot analysis. However, smaller transcripts of approximately 4, 2.3 and 1 kb were also detected in choriodecidua by Northern blot analysis and the 2.3-kb transcript and the 1-kb transcript were the only major transcripts detected in amnion and placenta, respectively. The presence of PLA 2 receptor mRNA in human gestational tissues indicates that an alternative non-catalytic pathway may contribute to the regulatory effects of sPLA 2 isozymes in these tissues. While the specificity and affinity of the various transcripts identified in this study have yet to be determined, PLA 2 isozymes released from human gestational tissues during pregnancy and at the time of labour may function as paracrine or autocrine mediators to affect cell function.