TY - JOUR
T1 - Lipoxin and resolvin biosynthesis is dependent on 5-lipoxygenase activating protein
AU - Lehmann, Christoph
AU - Homann, Julia
AU - Ball, Ann Katrin
AU - Blöcher, René
AU - Kleinschmidt, Thea K.
AU - Basavarajappa, Devaraj
AU - Angioni, Carlo
AU - Ferreirós, Nerea
AU - Häfner, Ann Kathrin
AU - Rådmark, Olof
AU - Proschak, Ewgenij
AU - Haeggström, Jesper Z.
AU - Geisslinger, Gerd
AU - Parnham, Michael J.
AU - Steinhilber, Dieter
AU - Kahnt, Astrid Stefanie
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Resolution of acute inflammation is an active process coordinated by proresolving lipid mediators (SPMs) such as lipoxins (LXs) and resolvins (Rvs), which are formed by the concerted action of 2 lipoxygenases (LOs). Because the exact molecular mechanisms of SPM biosynthesis are not completely understood, we aimed to investigate LX and D-type Rv formation in human leukocytes and HEK293T cells overexpressing leukotriene (LT) pathway enzymes. Activity assays in precursor (15-hydroxyeicosatetraenoic acids, 17-HDoHE)-treated granulocytes [polymorphonuclear leukocytes (PMNLs)] showed a strict dependence of LXA4/RvD1 biosynthesis on cell integrity, and incubation with recombinant human 5-LO did not lead to LX or Rv formation. Pharmacologic inhibition of 5-LO activating protein (FLAP) by MK-886 inhibited LXA4/RvD1 biosynthesis in precursor-treated PMNLs (drug concentration causing 50% inhibition ∼0.3/0.2 μM), as did knockdown of the enzyme in MM6 cells, and precursor-treated HEK293T overexpressing 5-LO produced high amounts of LXA4 only in the presence of FLAP. In addition, inhibition of cytosolic phospholipase A2α (cPLA2α) interfered with LXA4/RvD1 formation from exogenous precursors in PMNLs. Furthermore, inhibition of the LT synthases LTA4 hydrolase and LTC4 synthase in PMNL/platelet coincubations augmented LXA4 levels. These findings show that several enzymes known to be involved in the biosynthesis of proinflammatory LTs, such as FLAP and cPLA2α, also contribute to LX and Rv formation.
AB - Resolution of acute inflammation is an active process coordinated by proresolving lipid mediators (SPMs) such as lipoxins (LXs) and resolvins (Rvs), which are formed by the concerted action of 2 lipoxygenases (LOs). Because the exact molecular mechanisms of SPM biosynthesis are not completely understood, we aimed to investigate LX and D-type Rv formation in human leukocytes and HEK293T cells overexpressing leukotriene (LT) pathway enzymes. Activity assays in precursor (15-hydroxyeicosatetraenoic acids, 17-HDoHE)-treated granulocytes [polymorphonuclear leukocytes (PMNLs)] showed a strict dependence of LXA4/RvD1 biosynthesis on cell integrity, and incubation with recombinant human 5-LO did not lead to LX or Rv formation. Pharmacologic inhibition of 5-LO activating protein (FLAP) by MK-886 inhibited LXA4/RvD1 biosynthesis in precursor-treated PMNLs (drug concentration causing 50% inhibition ∼0.3/0.2 μM), as did knockdown of the enzyme in MM6 cells, and precursor-treated HEK293T overexpressing 5-LO produced high amounts of LXA4 only in the presence of FLAP. In addition, inhibition of cytosolic phospholipase A2α (cPLA2α) interfered with LXA4/RvD1 formation from exogenous precursors in PMNLs. Furthermore, inhibition of the LT synthases LTA4 hydrolase and LTC4 synthase in PMNL/platelet coincubations augmented LXA4 levels. These findings show that several enzymes known to be involved in the biosynthesis of proinflammatory LTs, such as FLAP and cPLA2α, also contribute to LX and Rv formation.
KW - Cytosolic phospholipase A2alpha
KW - LTA4 hydrolase
KW - LTC4 synthase
KW - Resolution of inflammation
UR - http://www.scopus.com/inward/record.url?scp=84973432158&partnerID=8YFLogxK
U2 - 10.1096/fj.15-275487
DO - 10.1096/fj.15-275487
M3 - Article
C2 - 26289316
AN - SCOPUS:84973432158
SN - 0892-6638
VL - 29
SP - 5029
EP - 5043
JO - FASEB Journal
JF - FASEB Journal
IS - 12
ER -