EXPRESSION OF ARACHIDONATE PLATELET-TYPE 12-LIPOXYGENASE IN HUMAN RHEUMATOID-ARTHRITIS TYPE-B SYNOVIOCYTES

In the present study, we have demonstrated platelet-type 12-lipoxygena se (12-LOX) expression in human rheumatoid arthritis (RA) type B synov iocytes by reverse-transcription polymerase chain reaction (RT-PCR), T he presence of 12-LOX mRNA in these cells was revealed by classical RT -PCR analysis using platelet-type 12-LOX cDNA primers and the PCR frag ment (246 bp) was purified, amplified and sequenced, By sequence analy sis, this fragment was determined to be 100% identical to that from pl atelet-type 12-LOX cDNA, Immunofluorescence data demonstrate that inte rleukin-1 beta (IL-1 beta) increases cellular 12-LOX protein, Other re sults associate specific inflammatory cytokines with the activity of 1 2-LOX in human RA type B synoviocytes, IL-1 beta increased 12S-hydroxy -5,8,10,14-eicosatetraenoic acid (12-HETE) production (4-fold) and we also observed an increase in 12-HETE production (2.5-fold) after incub ation of human RA type B synoviocytes with TNF alpha. In contrast to t he action of IL-1 beta on 12-HETE synthesis, IL-4 and IL-6 did not enh ance 12-HETE production, This is the first demonstration of platelet-t ype 12-LOX cDNA derived from the mRNA of cultured human RA type B syno viocytes. (C) 1997 Federation of European Biochemical Societies.