OBJECTIVE: Lipoxygenases (LOX) are lipid-peroxidating enzymes that are implicated in the pathogenesis of a variety of inflammatory disorders such as arthritis, psoriasis, and asthma. 15-LOX catalyzes the oxygenation of free arachidonic acid to 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE), which is reduced to 15-hydroxyeicosatetraenoic acid (15-HETE). The biological role of 15-HETE is less clear. We sought to determine if cultured human rheumatoid synovial cells were able to express 15-LOX mRNA, leading to the synthesis of 15-HETE, and to examine the effect of different cytokines on 15-LOX activity. METHODS: Adherent synovial cells were obtained by enzymatic digestion of rheumatoid synovium, isolated from patients with rheumatoid arthritis (RA) undergoing hip synovectomy. Between passages 4 and 8, reticulocyte-type 15-LOX expression in these cells was determined by reverse transcription-polymerase chain reaction (RT-PCR) in situ and confirmed by classical RT-PCR analysis followed by enzymatic digestion. The PCR fragment was purified, amplified, and sequenced. Cultured synovial cells were incubated with or without different cytokines and exogenous [1-(14)C] arachidonic acid metabolism of synoviocytes was analyzed by reverse phase high performance liquid chromatography (RP-HPLC). RESULTS: RT-PCR results showed that human RA type B synoviocytes expressed a reticulocyte-type 15-LOX. By sequence analysis, the PCR fragment (474 bp) was determined to be 100% identical to that of reticulocyte-type 15-LOX cDNA. Other results associated specific inflammatory cytokines with the activity of 15-LOX in these cells. RP-HPLC analysis showed that interleukin 4 (IL-4) increased 15-HETE production (2.4-fold); we also observed an increase in 15-HETE production (1.2-fold) after incubation of the cells with IL-1beta. CONCLUSION: Human RA type B synoviocytes are able to express 15-LOX mRNA leading to the synthesis of 15-HETE, which is modulated by various cytokines that play a major role in the pathophysiology of RA, especially IL-4 and IL-1.
OBJECTIVE: Lipoxygenases (LOX) are lipid-peroxidating enzymes that are implicated in the pathogenesis of a variety of inflammatory disorders such as arthritis, psoriasis, and asthma. 15-LOX catalyzes the oxygenation of free arachidonic acid to 15-hydroperoxy-5,8,11,13-eicosatetraenoic acid (15-HPETE), which is reduced to 15-hydroxyeicosatetraenoic acid (15-HETE). The biological role of 15-HETE is less clear. We sought to determine if cultured humanrheumatoid synovial cells were able to express 15-LOX mRNA, leading to the synthesis of 15-HETE, and to examine the effect of different cytokines on 15-LOX activity. METHODS: Adherent synovial cells were obtained by enzymatic digestion of rheumatoid synovium, isolated from patients with rheumatoid arthritis (RA) undergoing hip synovectomy. Between passages 4 and 8, reticulocyte-type 15-LOX expression in these cells was determined by reverse transcription-polymerase chain reaction (RT-PCR) in situ and confirmed by classical RT-PCR analysis followed by enzymatic digestion. The PCR fragment was purified, amplified, and sequenced. Cultured synovial cells were incubated with or without different cytokines and exogenous [1-(14)C] arachidonic acid metabolism of synoviocytes was analyzed by reverse phase high performance liquid chromatography (RP-HPLC). RESULTS: RT-PCR results showed that humanRA type B synoviocytes expressed a reticulocyte-type 15-LOX. By sequence analysis, the PCR fragment (474 bp) was determined to be 100% identical to that of reticulocyte-type 15-LOX cDNA. Other results associated specific inflammatory cytokines with the activity of 15-LOX in these cells. RP-HPLC analysis showed that interleukin 4 (IL-4) increased 15-HETE production (2.4-fold); we also observed an increase in 15-HETE production (1.2-fold) after incubation of the cells with IL-1beta. CONCLUSION:HumanRA type B synoviocytes are able to express 15-LOX mRNA leading to the synthesis of 15-HETE, which is modulated by various cytokines that play a major role in the pathophysiology of RA, especially IL-4 and IL-1.
Authors: Johan Ockinger; Pablo Serrano-Fernández; Steffen Möller; Saleh M Ibrahim; Tomas Olsson; Maja Jagodic Journal: Genetics Date: 2006-04-19 Impact factor: 4.562
Authors: Bertrand Liagre; Pascale Vergne-Salle; Cecile Corbiere; Jean L Charissoux; Jean L Beneytout Journal: Arthritis Res Ther Date: 2004-06-17 Impact factor: 5.156
Authors: M L Kowalski; A Wolska; J Grzegorczyk; J Hilt; M Jarzebska; M Drobniewski; M Synder; M Kurowski Journal: Mediators Inflamm Date: 2008 Impact factor: 4.711