Capacity for repeatable leukotriene generation after transient stimulation of mast cells and macrophages

Brock, G. Thomas; McNISH, W. Robert; Peters‐Golden, Marc

doi:10.1042/bj3290519

Cited by 31 publications

(40 citation statements)

References 25 publications

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“…Similarly, we find that S271A 5-LO is comparable with WT 5-LO in terms of membrane association after cell stimulation (not shown), indicating that phosphorylation of Ser-271 is not necessary for membrane association. When leukocytes are stimulated in a way that activates 5-LO and triggers LT biosynthesis, 5-LO moves to membranes within seconds (54), newly biosynthesized LTs are detectable outside the cell within seconds, and LT production ends after several minutes (55). Contrasting with this are the rates of import and export of 5-LO.…”

Section: Discussionmentioning

confidence: 84%

Phosphorylation of Serine 271 on 5-Lipoxygenase and Its Role in Nuclear Export

Flamand

Luo

Peters‐Golden

et al. 2009

Journal of Biological Chemistry

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The enzyme 5-lipoxygenase (5-LO) initiates the biosynthesis of leukotrienes, inflammatory mediators involved in immune diseases and defense. The subcellular localization of 5-LO is regulated, with nuclear import commonly leading to increased leukotriene production. We report here that 5-LO is constitutively phosphorylated on Ser-271 in transfected NIH 3T3 cells. This residue is nested in a classical nuclear export sequence, and phosphorylated Ser-271 5-LO was exclusively found in the nucleus by immunofluorescence and by fractionation techniques. Mutation of Ser-271 to Ala allowed nuclear export of 5-LO that was blocked by the specific nuclear export inhibitor leptomycin b, suggesting that phosphorylation of Ser-271 serves to interfere with exportin-1-mediated nuclear export. Consistent with previous reports that purified 5-LO can be phosphorylated on Ser-271 in vitro by MAPK-activated protein kinase 2, the nuclear export of 5-LO was increased by either treatment with the p38 inhibitor SB 203,580 or co-expression of a kinasedeficient p38 MAPK. Nuclear export of 5-LO can also be induced by KN-93, an inhibitor of Ca 2؉ /calmodulin-dependent kinase II, and the effects of SB 203,580 plus KN-93 are additive. Finally, HeLa cells, which lack nuclear 5-LO, also lack constitutive phosphorylation of Ser-271. Taken together, these results indicate that the phosphorylation of Ser-271 serves to inhibit the nuclear export of 5-LO. This action works in concert with nuclear import, which is regulated by phosphorylation on Ser-523, to determine the subcellular distribution of 5-LO, which in turn regulates leukotriene biosynthesis. Leukotrienes (LTs)2 are intercellular messengers that play critical roles in inflammatory and allergic diseases (for review, see Ref. 1). In particular, LTB 4 promotes the recruitment and activation of leukocytes, stimulates phagocytosis and killing of pathogens, and promotes the synthesis of proteins involved in the inflammatory process. Through these effects and others, the overproduction of LTB 4 helps drive the chronic inflammation that characterizes asthma (2-4), bronchitis (5-7), and rhinitis (8). On the other hand, the underproduction of LTB 4 represents a form of immune suppression, resulting in impaired host defense against infectious pathogens. Thus, LTB 4 promotes immune defense against pathogenic bacteria (9 -11), fungi (12), viruses (13), and parasites (14 -16). Significantly, reduced LT biosynthesis correlates with increased susceptibility to infectious disease in numerous conditions, including cigarette smoking (17, 18), malnutrition (19 -22), vitamin D deficiency (23), human immunodeficiency virus infection (24, 25), and type II diabetes (26).The enzyme 5-lipoxygenase (5-LO) initiates the biosynthesis of LTs from the polyunsaturated fatty acid arachidonic acid and represents a key point of regulation. In its resting state 5-LO is a soluble enzyme that can reside in either the cytoplasm or the nucleus (27-29). The 5-LO protein has three nuclear import sequences that can be regulated and f...

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Section: Discussionmentioning

confidence: 84%

Phosphorylation of Serine 271 on 5-Lipoxygenase and Its Role in Nuclear Export

Flamand

Luo

Peters‐Golden

et al. 2009

Journal of Biological Chemistry

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“…MK-886 is known to bind to FLAP and prevent the synthesis of LTs from endogenous AA in intact cells, by blocking membrane association of 5-LO (39). However, other reports state that MK-886 may inhibit LT biosynthesis without any effect on membrane association (9,40), suggesting that LT biosynthesis can be a tow-step process consisting of FLAP-independent binding of 5-LO to the membrane of the nuclear envelope, followed by FLAP-dependent activation of the enzyme. In our study, treatment of A-23187-stimulated DC with graded concentrations of MK-886, a FLAP-specific inhibitor (Fig.…”

Section: Role Of Flap In 5-lo Metabolismmentioning

confidence: 98%

Prostaglandins Inhibit 5-Lipoxygenase-Activating Protein Expression and Leukotriene B4 Production from Dendritic Cells Via an IL-10-Dependent Mechanism

Harizi

Juzan

Moreau

et al. 2003

The Journal of Immunology

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PGs produced from arachidonic acid by the action of cyclooxygenase enzymes play a pivotal role in the regulation of both inflammatory and immune responses. Because leukotriene B4 (LTB4), a product of 5-lipoxygenase (5-LO) pathway, can exert numerous immunoregulatory and proinflammatory activities, we examined the effects of PGs on LTB4 release from dendritic cells (DC) and from peritoneal macrophages. In concentration-dependent manner, PGE1 and PGE2 inhibited the production of LTB4 from DC, but not from peritoneal macrophage, with an IC50 of 0.04 μM. The same effect was observed with MK-886, a 5-LO-activating protein (FLAP)-specific inhibitor. The decreased release of LTB4 was associated with an enhanced level of IL-10. Furthermore, the inhibition of LTB4 synthesis by PGs was significantly reversed by anti-IL-10, suggesting the involvement of an IL-10-dependent mechanism. Hence, we examined the effects of exogenous IL-10 on the 5-LO pathway. We demonstrate that IL-10 suppresses the production of LTB4 from DC by inhibiting FLAP protein expression without any effect on 5-LO and cytosolic phospholipase A2. Taken together, our results suggest links between DC cyclooxygenase and 5-LO pathways during the inflammatory response, and FLAP is a key target for the PG-induced IL-10-suppressive effects.

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“…However, in male neutrophils, a substantial part of 5-LO was located at the perinuclear region already in resting cells, 5-LO only marginally redistributed upon stimulation, and less 5-LO products were formed. Previous findings suggest that 5-LO already associated with the nuclear envelope at the time of cell stimulation may be less active and/or display a changed substrate specificity (47,48). Thus, the perinuclear 5-LO localization induced by 5a-DHT may be a regulatory mechanism in males, which attenuates LT formation at sites of inflammation.…”

Section: Gender-specific 5-lo Activity In Human Neutrophilsmentioning

confidence: 99%

5-Lipoxygenase: mechanisms of regulation

Rådmark

Samuelsson

2009

Journal of Lipid Research

143

115

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5-Lipoxygenase (5-LO) catalyzes two steps in biosynthesis of leukotrienes (LTs), a group of lipid mediators of inflammation derived from arachidonic acid (AA). LT antagonists are used in treatment of asthma; more recently a potential role also in atherosclerosis has raised considerable interest. Furthermore, possible effects of 5-LO metabolites in relation to tumorigenesis have emerged. Thus, an understanding of the biochemistry of this lipoxygenase has potential implications for treatment of various diseases.-Rådmark, O., and B. Samuelsson. 5-Lipoxygenase: mechanisms of regulation. J. Lipid Res. 2009. 50: S40-S45.

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Capacity for repeatable leukotriene generation after transient stimulation of mast cells and macrophages

Cited by 31 publications

References 25 publications

Phosphorylation of Serine 271 on 5-Lipoxygenase and Its Role in Nuclear Export

Phosphorylation of Serine 271 on 5-Lipoxygenase and Its Role in Nuclear Export

Prostaglandins Inhibit 5-Lipoxygenase-Activating Protein Expression and Leukotriene B4 Production from Dendritic Cells Via an IL-10-Dependent Mechanism

5-Lipoxygenase: mechanisms of regulation

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