15-hydroxy-5-8-11-13-eicosatetraenoic-acid and Arthritis--Rheumatoid

To determine the association of polyunsaturated fatty acid (PUFA)-derived lipid mediators with progression from rheumatoid arthritis (RA)-related autoimmunity to inflammatory arthritis (IA).. We conducted a prospective cohort study using data from the Studies of the Etiology of Rheumatoid Arthritis (SERA). SERA enrolled first-degree relatives (FDRs) of individuals with RA (FDR cohort) and individuals who screened positive for RA-related autoantibodies at health fairs (screened cohort). We followed up 133 anti-cyclic citrullinated peptide 3.1 (anti-CCP3.1)-positive participants, 29 of whom developed IA. Lipid mediators selected a priori were quantified from stored plasma samples using liquid chromatography tandem mass spectrometry. We fit multivariable Cox proportional hazards models for each lipid mediator as a time-varying variable. For lipid mediators found to be significantly associated with IA, we then examined interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor (TNF) as potential statistical mediators.. For every 1 natural log pg/ml increase in the circulating plasma levels of proinflammatory 5-HETE, the risk of developing IA increased by 241% (hazard ratio 2.41 [95% confidence interval 1.43-4.07]) after adjusting for age at baseline, cohort (FDR or screened), and shared epitope status. The models examining 15-HETE and 17-HDHA had the same trend but did not reach significance. We did not find evidence that the association between 5-HETE and IA risk was influenced by the proinflammatory cytokines tested.. In a prospective cohort of anti-CCP-positive individuals, higher levels of 5-HETE, an important precursor to proinflammatory leukotrienes, is associated with subsequent IA. Our findings highlight the potential significance of these PUFA metabolites in pre-RA populations.

Topics: Adult; Aged; Anti-Citrullinated Protein Antibodies; Arthritis, Rheumatoid; Autoimmunity; Cohort Studies; Disease Progression; Docosahexaenoic Acids; Family; Fatty Acids, Unsaturated; Female; Humans; Hydroxyeicosatetraenoic Acids; Incidence; Interleukin-1beta; Interleukin-6; Interleukin-8; Male; Mediation Analysis; Middle Aged; Multivariate Analysis; Proportional Hazards Models; Prospective Studies; Tumor Necrosis Factor-alpha

Metabolites from arachidonic acids play the pivotal roles in inflammatory arthritis. Arachidonic acid could be metabolized by cyclooxygenase (COX) and lipoxygenase (LOX) to produce the bioactive eicosanoids. Although the down-stream products of COX including prostaglandin E2 are well-known inflammatory stimulators, the role of LOX products in inflammatory arthritis is still unclear. Here we found that the downstream product of 15-LOX, 15-S-hydroxyeicosatetraenoic acid (15-(S)-HETE), can enhance the expression of placenta growth factor (PLGF), which is recently considered to play an important role in rheumatoid arthritis. 15-(S)-HETE increased the expression of PLGF in human rheumatoid arthritis synovial fibroblasts in a time-dependent and concentration-dependent manner. PI3K-Akt, NF-κB signaling pathways were involved in the potentiation effects of 15-(S)-HETE. In addition, COX-2 was up-regulated by the treatment of 15-(S)-HETE and the increase of COX-2 expression participated in 15-(S)-HETE-induced PLGF expression, which was confirmed by COX-2 shRNA or pharmacological COX-2 inhibitor. Moreover, it was found that treatment of prostaglandin E2 (PGE2), which was the main down-stream metabolite of COX-2, increased the expression of PLGF. EP1, EP2, EP3 and EP4 agonists could up-regulate PLGF as well. In animal studies, we found that the adjuvant-induced expression of PLGF and COX-2 was inhibited in 15-LOX knockout mice. These results indicated that PLGF up-regulation by 15-LOX downstream product may be involved in inflammatory arthritis.

Topics: Animals; Arachidonate 15-Lipoxygenase; Arthritis, Rheumatoid; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Dinoprostone; Fibroblasts; Gene Knockout Techniques; Humans; Hydroxyeicosatetraenoic Acids; Mice; Mice, Inbred C57BL; NF-kappa B; Phosphatidylinositol 3-Kinases; Placenta Growth Factor; Pregnancy Proteins; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; Synovial Membrane; Up-Regulation

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.. 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).. 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.. 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.

Topics: Arachidonate 15-Lipoxygenase; Arachidonic Acids; Arthritis, Rheumatoid; Cytokines; Humans; Hydroxyeicosatetraenoic Acids; Interleukin-1; Interleukin-4; Reticulocytes; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Synovial Membrane

We have examined the ability of interleukin-4 (IL-4), interleukin-10 (IL-10) and interleukin-1 receptor antagonist protein (IL-1ra) to regulate spontaneous interleukin-8 (IL-8) production in cultured SF mononuclear cells (SFMC) from RA. Furthermore, we examined whether IL-4, IL-10, or IL-1ra could influence the production of the arachidonic acid products leukotriene B4 (LTB4), 12-hydroxy-eicosatetraenoic acid (12-HETE) and 15-hydroxy-eicosatetraenoic acid (15-HETE). IL-4 induced a maximal suppression of 75% in the IL-8 secretion in SFMC from 10.0 ng/ml down to 2.5 ng/ml after 24 h and from 17.2 ng/ml to 4.2 ng/ml after 72 h of culture. IL-10 induced a 55% inhibition of the IL-8 secretion at 24 h and a 40% inhibition at 72 h. IL-1ra did not change the spontaneous IL-8 secretion from rheumatoid SFMC. We also examined, whether addition of IL-4, IL-10 or IL-1ra was able to modulate formation of the arachidonic acid products LTB4, 12-HETE and 15-HETE in cultured SF cells, stimulated with the calcium ionophore A23187. 15-HETE was not detected in untreated cultures, nor in IL-10 or IL-1ra treated cultures. IL-4, however, stimulated the formation of the anti-inflammatory mediator; 15-HETE (23 ng/10(6) cells). These results suggest that IL-4 or IL-10, could have beneficial anti-inflammatory effects in RA.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Arthritis, Rheumatoid; Humans; Hydroxyeicosatetraenoic Acids; Interleukin 1 Receptor Antagonist Protein; Interleukin-10; Interleukin-4; Interleukin-8; Leukotriene B4; Sialoglycoproteins; Synovial Fluid